SemaChecking.cpp revision 9d0840141a0922e2d8b1d322f21ef51803ede23d 
1//===--- SemaChecking.cpp - Extra Semantic Checking -----------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file implements extra semantic analysis beyond what is enforced
11//  by the C type system.
12//
13//===----------------------------------------------------------------------===//
14
15#include "clang/Sema/SemaInternal.h"
16#include "clang/AST/ASTContext.h"
17#include "clang/AST/CharUnits.h"
18#include "clang/AST/DeclCXX.h"
19#include "clang/AST/DeclObjC.h"
20#include "clang/AST/DeclObjC.h"
21#include "clang/AST/EvaluatedExprVisitor.h"
22#include "clang/AST/Expr.h"
23#include "clang/AST/ExprCXX.h"
24#include "clang/AST/ExprObjC.h"
25#include "clang/AST/StmtCXX.h"
26#include "clang/AST/StmtObjC.h"
27#include "clang/Analysis/Analyses/FormatString.h"
28#include "clang/Basic/ConvertUTF.h"
29#include "clang/Basic/TargetBuiltins.h"
30#include "clang/Basic/TargetInfo.h"
31#include "clang/Lex/Preprocessor.h"
32#include "clang/Sema/Initialization.h"
33#include "clang/Sema/Initialization.h"
34#include "clang/Sema/Lookup.h"
35#include "clang/Sema/ScopeInfo.h"
36#include "clang/Sema/Sema.h"
37#include "llvm/ADT/BitVector.h"
38#include "llvm/ADT/STLExtras.h"
39#include "llvm/ADT/SmallString.h"
40#include "llvm/Support/raw_ostream.h"
41#include <limits>
42using namespace clang;
43using namespace sema;
44
45SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL,
46                                                    unsigned ByteNo) const {
47  return SL->getLocationOfByte(ByteNo, PP.getSourceManager(),
48                               PP.getLangOpts(), PP.getTargetInfo());
49}
50
51/// Checks that a call expression's argument count is the desired number.
52/// This is useful when doing custom type-checking.  Returns true on error.
53static bool checkArgCount(Sema &S, CallExpr *call, unsigned desiredArgCount) {
54  unsigned argCount = call->getNumArgs();
55  if (argCount == desiredArgCount) return false;
56
57  if (argCount < desiredArgCount)
58    return S.Diag(call->getLocEnd(), diag::err_typecheck_call_too_few_args)
59        << 0 /*function call*/ << desiredArgCount << argCount
60        << call->getSourceRange();
61
62  // Highlight all the excess arguments.
63  SourceRange range(call->getArg(desiredArgCount)->getLocStart(),
64                    call->getArg(argCount - 1)->getLocEnd());
65
66  return S.Diag(range.getBegin(), diag::err_typecheck_call_too_many_args)
67    << 0 /*function call*/ << desiredArgCount << argCount
68    << call->getArg(1)->getSourceRange();
69}
70
71/// Check that the first argument to __builtin_annotation is an integer
72/// and the second argument is a non-wide string literal.
73static bool SemaBuiltinAnnotation(Sema &S, CallExpr *TheCall) {
74  if (checkArgCount(S, TheCall, 2))
75    return true;
76
77  // First argument should be an integer.
78  Expr *ValArg = TheCall->getArg(0);
79  QualType Ty = ValArg->getType();
80  if (!Ty->isIntegerType()) {
81    S.Diag(ValArg->getLocStart(), diag::err_builtin_annotation_first_arg)
82      << ValArg->getSourceRange();
83    return true;
84  }
85
86  // Second argument should be a constant string.
87  Expr *StrArg = TheCall->getArg(1)->IgnoreParenCasts();
88  StringLiteral *Literal = dyn_cast<StringLiteral>(StrArg);
89  if (!Literal || !Literal->isAscii()) {
90    S.Diag(StrArg->getLocStart(), diag::err_builtin_annotation_second_arg)
91      << StrArg->getSourceRange();
92    return true;
93  }
94
95  TheCall->setType(Ty);
96  return false;
97}
98
99ExprResult
100Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
101  ExprResult TheCallResult(Owned(TheCall));
102
103  // Find out if any arguments are required to be integer constant expressions.
104  unsigned ICEArguments = 0;
105  ASTContext::GetBuiltinTypeError Error;
106  Context.GetBuiltinType(BuiltinID, Error, &ICEArguments);
107  if (Error != ASTContext::GE_None)
108    ICEArguments = 0;  // Don't diagnose previously diagnosed errors.
109
110  // If any arguments are required to be ICE's, check and diagnose.
111  for (unsigned ArgNo = 0; ICEArguments != 0; ++ArgNo) {
112    // Skip arguments not required to be ICE's.
113    if ((ICEArguments & (1 << ArgNo)) == 0) continue;
114
115    llvm::APSInt Result;
116    if (SemaBuiltinConstantArg(TheCall, ArgNo, Result))
117      return true;
118    ICEArguments &= ~(1 << ArgNo);
119  }
120
121  switch (BuiltinID) {
122  case Builtin::BI__builtin___CFStringMakeConstantString:
123    assert(TheCall->getNumArgs() == 1 &&
124           "Wrong # arguments to builtin CFStringMakeConstantString");
125    if (CheckObjCString(TheCall->getArg(0)))
126      return ExprError();
127    break;
128  case Builtin::BI__builtin_stdarg_start:
129  case Builtin::BI__builtin_va_start:
130    if (SemaBuiltinVAStart(TheCall))
131      return ExprError();
132    break;
133  case Builtin::BI__builtin_isgreater:
134  case Builtin::BI__builtin_isgreaterequal:
135  case Builtin::BI__builtin_isless:
136  case Builtin::BI__builtin_islessequal:
137  case Builtin::BI__builtin_islessgreater:
138  case Builtin::BI__builtin_isunordered:
139    if (SemaBuiltinUnorderedCompare(TheCall))
140      return ExprError();
141    break;
142  case Builtin::BI__builtin_fpclassify:
143    if (SemaBuiltinFPClassification(TheCall, 6))
144      return ExprError();
145    break;
146  case Builtin::BI__builtin_isfinite:
147  case Builtin::BI__builtin_isinf:
148  case Builtin::BI__builtin_isinf_sign:
149  case Builtin::BI__builtin_isnan:
150  case Builtin::BI__builtin_isnormal:
151    if (SemaBuiltinFPClassification(TheCall, 1))
152      return ExprError();
153    break;
154  case Builtin::BI__builtin_shufflevector:
155    return SemaBuiltinShuffleVector(TheCall);
156    // TheCall will be freed by the smart pointer here, but that's fine, since
157    // SemaBuiltinShuffleVector guts it, but then doesn't release it.
158  case Builtin::BI__builtin_prefetch:
159    if (SemaBuiltinPrefetch(TheCall))
160      return ExprError();
161    break;
162  case Builtin::BI__builtin_object_size:
163    if (SemaBuiltinObjectSize(TheCall))
164      return ExprError();
165    break;
166  case Builtin::BI__builtin_longjmp:
167    if (SemaBuiltinLongjmp(TheCall))
168      return ExprError();
169    break;
170
171  case Builtin::BI__builtin_classify_type:
172    if (checkArgCount(*this, TheCall, 1)) return true;
173    TheCall->setType(Context.IntTy);
174    break;
175  case Builtin::BI__builtin_constant_p:
176    if (checkArgCount(*this, TheCall, 1)) return true;
177    TheCall->setType(Context.IntTy);
178    break;
179  case Builtin::BI__sync_fetch_and_add:
180  case Builtin::BI__sync_fetch_and_add_1:
181  case Builtin::BI__sync_fetch_and_add_2:
182  case Builtin::BI__sync_fetch_and_add_4:
183  case Builtin::BI__sync_fetch_and_add_8:
184  case Builtin::BI__sync_fetch_and_add_16:
185  case Builtin::BI__sync_fetch_and_sub:
186  case Builtin::BI__sync_fetch_and_sub_1:
187  case Builtin::BI__sync_fetch_and_sub_2:
188  case Builtin::BI__sync_fetch_and_sub_4:
189  case Builtin::BI__sync_fetch_and_sub_8:
190  case Builtin::BI__sync_fetch_and_sub_16:
191  case Builtin::BI__sync_fetch_and_or:
192  case Builtin::BI__sync_fetch_and_or_1:
193  case Builtin::BI__sync_fetch_and_or_2:
194  case Builtin::BI__sync_fetch_and_or_4:
195  case Builtin::BI__sync_fetch_and_or_8:
196  case Builtin::BI__sync_fetch_and_or_16:
197  case Builtin::BI__sync_fetch_and_and:
198  case Builtin::BI__sync_fetch_and_and_1:
199  case Builtin::BI__sync_fetch_and_and_2:
200  case Builtin::BI__sync_fetch_and_and_4:
201  case Builtin::BI__sync_fetch_and_and_8:
202  case Builtin::BI__sync_fetch_and_and_16:
203  case Builtin::BI__sync_fetch_and_xor:
204  case Builtin::BI__sync_fetch_and_xor_1:
205  case Builtin::BI__sync_fetch_and_xor_2:
206  case Builtin::BI__sync_fetch_and_xor_4:
207  case Builtin::BI__sync_fetch_and_xor_8:
208  case Builtin::BI__sync_fetch_and_xor_16:
209  case Builtin::BI__sync_add_and_fetch:
210  case Builtin::BI__sync_add_and_fetch_1:
211  case Builtin::BI__sync_add_and_fetch_2:
212  case Builtin::BI__sync_add_and_fetch_4:
213  case Builtin::BI__sync_add_and_fetch_8:
214  case Builtin::BI__sync_add_and_fetch_16:
215  case Builtin::BI__sync_sub_and_fetch:
216  case Builtin::BI__sync_sub_and_fetch_1:
217  case Builtin::BI__sync_sub_and_fetch_2:
218  case Builtin::BI__sync_sub_and_fetch_4:
219  case Builtin::BI__sync_sub_and_fetch_8:
220  case Builtin::BI__sync_sub_and_fetch_16:
221  case Builtin::BI__sync_and_and_fetch:
222  case Builtin::BI__sync_and_and_fetch_1:
223  case Builtin::BI__sync_and_and_fetch_2:
224  case Builtin::BI__sync_and_and_fetch_4:
225  case Builtin::BI__sync_and_and_fetch_8:
226  case Builtin::BI__sync_and_and_fetch_16:
227  case Builtin::BI__sync_or_and_fetch:
228  case Builtin::BI__sync_or_and_fetch_1:
229  case Builtin::BI__sync_or_and_fetch_2:
230  case Builtin::BI__sync_or_and_fetch_4:
231  case Builtin::BI__sync_or_and_fetch_8:
232  case Builtin::BI__sync_or_and_fetch_16:
233  case Builtin::BI__sync_xor_and_fetch:
234  case Builtin::BI__sync_xor_and_fetch_1:
235  case Builtin::BI__sync_xor_and_fetch_2:
236  case Builtin::BI__sync_xor_and_fetch_4:
237  case Builtin::BI__sync_xor_and_fetch_8:
238  case Builtin::BI__sync_xor_and_fetch_16:
239  case Builtin::BI__sync_val_compare_and_swap:
240  case Builtin::BI__sync_val_compare_and_swap_1:
241  case Builtin::BI__sync_val_compare_and_swap_2:
242  case Builtin::BI__sync_val_compare_and_swap_4:
243  case Builtin::BI__sync_val_compare_and_swap_8:
244  case Builtin::BI__sync_val_compare_and_swap_16:
245  case Builtin::BI__sync_bool_compare_and_swap:
246  case Builtin::BI__sync_bool_compare_and_swap_1:
247  case Builtin::BI__sync_bool_compare_and_swap_2:
248  case Builtin::BI__sync_bool_compare_and_swap_4:
249  case Builtin::BI__sync_bool_compare_and_swap_8:
250  case Builtin::BI__sync_bool_compare_and_swap_16:
251  case Builtin::BI__sync_lock_test_and_set:
252  case Builtin::BI__sync_lock_test_and_set_1:
253  case Builtin::BI__sync_lock_test_and_set_2:
254  case Builtin::BI__sync_lock_test_and_set_4:
255  case Builtin::BI__sync_lock_test_and_set_8:
256  case Builtin::BI__sync_lock_test_and_set_16:
257  case Builtin::BI__sync_lock_release:
258  case Builtin::BI__sync_lock_release_1:
259  case Builtin::BI__sync_lock_release_2:
260  case Builtin::BI__sync_lock_release_4:
261  case Builtin::BI__sync_lock_release_8:
262  case Builtin::BI__sync_lock_release_16:
263  case Builtin::BI__sync_swap:
264  case Builtin::BI__sync_swap_1:
265  case Builtin::BI__sync_swap_2:
266  case Builtin::BI__sync_swap_4:
267  case Builtin::BI__sync_swap_8:
268  case Builtin::BI__sync_swap_16:
269    return SemaBuiltinAtomicOverloaded(TheCallResult);
270#define BUILTIN(ID, TYPE, ATTRS)
271#define ATOMIC_BUILTIN(ID, TYPE, ATTRS) \
272  case Builtin::BI##ID: \
273    return SemaAtomicOpsOverloaded(TheCallResult, AtomicExpr::AO##ID);
274#include "clang/Basic/Builtins.def"
275  case Builtin::BI__builtin_annotation:
276    if (SemaBuiltinAnnotation(*this, TheCall))
277      return ExprError();
278    break;
279  }
280
281  // Since the target specific builtins for each arch overlap, only check those
282  // of the arch we are compiling for.
283  if (BuiltinID >= Builtin::FirstTSBuiltin) {
284    switch (Context.getTargetInfo().getTriple().getArch()) {
285      case llvm::Triple::arm:
286      case llvm::Triple::thumb:
287        if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall))
288          return ExprError();
289        break;
290      case llvm::Triple::mips:
291      case llvm::Triple::mipsel:
292      case llvm::Triple::mips64:
293      case llvm::Triple::mips64el:
294        if (CheckMipsBuiltinFunctionCall(BuiltinID, TheCall))
295          return ExprError();
296        break;
297      default:
298        break;
299    }
300  }
301
302  return TheCallResult;
303}
304
305// Get the valid immediate range for the specified NEON type code.
306static unsigned RFT(unsigned t, bool shift = false) {
307  NeonTypeFlags Type(t);
308  int IsQuad = Type.isQuad();
309  switch (Type.getEltType()) {
310  case NeonTypeFlags::Int8:
311  case NeonTypeFlags::Poly8:
312    return shift ? 7 : (8 << IsQuad) - 1;
313  case NeonTypeFlags::Int16:
314  case NeonTypeFlags::Poly16:
315    return shift ? 15 : (4 << IsQuad) - 1;
316  case NeonTypeFlags::Int32:
317    return shift ? 31 : (2 << IsQuad) - 1;
318  case NeonTypeFlags::Int64:
319    return shift ? 63 : (1 << IsQuad) - 1;
320  case NeonTypeFlags::Float16:
321    assert(!shift && "cannot shift float types!");
322    return (4 << IsQuad) - 1;
323  case NeonTypeFlags::Float32:
324    assert(!shift && "cannot shift float types!");
325    return (2 << IsQuad) - 1;
326  }
327  llvm_unreachable("Invalid NeonTypeFlag!");
328}
329
330/// getNeonEltType - Return the QualType corresponding to the elements of
331/// the vector type specified by the NeonTypeFlags.  This is used to check
332/// the pointer arguments for Neon load/store intrinsics.
333static QualType getNeonEltType(NeonTypeFlags Flags, ASTContext &Context) {
334  switch (Flags.getEltType()) {
335  case NeonTypeFlags::Int8:
336    return Flags.isUnsigned() ? Context.UnsignedCharTy : Context.SignedCharTy;
337  case NeonTypeFlags::Int16:
338    return Flags.isUnsigned() ? Context.UnsignedShortTy : Context.ShortTy;
339  case NeonTypeFlags::Int32:
340    return Flags.isUnsigned() ? Context.UnsignedIntTy : Context.IntTy;
341  case NeonTypeFlags::Int64:
342    return Flags.isUnsigned() ? Context.UnsignedLongLongTy : Context.LongLongTy;
343  case NeonTypeFlags::Poly8:
344    return Context.SignedCharTy;
345  case NeonTypeFlags::Poly16:
346    return Context.ShortTy;
347  case NeonTypeFlags::Float16:
348    return Context.UnsignedShortTy;
349  case NeonTypeFlags::Float32:
350    return Context.FloatTy;
351  }
352  llvm_unreachable("Invalid NeonTypeFlag!");
353}
354
355bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
356  llvm::APSInt Result;
357
358  uint64_t mask = 0;
359  unsigned TV = 0;
360  int PtrArgNum = -1;
361  bool HasConstPtr = false;
362  switch (BuiltinID) {
363#define GET_NEON_OVERLOAD_CHECK
364#include "clang/Basic/arm_neon.inc"
365#undef GET_NEON_OVERLOAD_CHECK
366  }
367
368  // For NEON intrinsics which are overloaded on vector element type, validate
369  // the immediate which specifies which variant to emit.
370  unsigned ImmArg = TheCall->getNumArgs()-1;
371  if (mask) {
372    if (SemaBuiltinConstantArg(TheCall, ImmArg, Result))
373      return true;
374
375    TV = Result.getLimitedValue(64);
376    if ((TV > 63) || (mask & (1ULL << TV)) == 0)
377      return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code)
378        << TheCall->getArg(ImmArg)->getSourceRange();
379  }
380
381  if (PtrArgNum >= 0) {
382    // Check that pointer arguments have the specified type.
383    Expr *Arg = TheCall->getArg(PtrArgNum);
384    if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg))
385      Arg = ICE->getSubExpr();
386    ExprResult RHS = DefaultFunctionArrayLvalueConversion(Arg);
387    QualType RHSTy = RHS.get()->getType();
388    QualType EltTy = getNeonEltType(NeonTypeFlags(TV), Context);
389    if (HasConstPtr)
390      EltTy = EltTy.withConst();
391    QualType LHSTy = Context.getPointerType(EltTy);
392    AssignConvertType ConvTy;
393    ConvTy = CheckSingleAssignmentConstraints(LHSTy, RHS);
394    if (RHS.isInvalid())
395      return true;
396    if (DiagnoseAssignmentResult(ConvTy, Arg->getLocStart(), LHSTy, RHSTy,
397                                 RHS.get(), AA_Assigning))
398      return true;
399  }
400
401  // For NEON intrinsics which take an immediate value as part of the
402  // instruction, range check them here.
403  unsigned i = 0, l = 0, u = 0;
404  switch (BuiltinID) {
405  default: return false;
406  case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break;
407  case ARM::BI__builtin_arm_usat: i = 1; u = 31; break;
408  case ARM::BI__builtin_arm_vcvtr_f:
409  case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break;
410#define GET_NEON_IMMEDIATE_CHECK
411#include "clang/Basic/arm_neon.inc"
412#undef GET_NEON_IMMEDIATE_CHECK
413  };
414
415  // We can't check the value of a dependent argument.
416  if (TheCall->getArg(i)->isTypeDependent() ||
417      TheCall->getArg(i)->isValueDependent())
418    return false;
419
420  // Check that the immediate argument is actually a constant.
421  if (SemaBuiltinConstantArg(TheCall, i, Result))
422    return true;
423
424  // Range check against the upper/lower values for this isntruction.
425  unsigned Val = Result.getZExtValue();
426  if (Val < l || Val > (u + l))
427    return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
428      << l << u+l << TheCall->getArg(i)->getSourceRange();
429
430  // FIXME: VFP Intrinsics should error if VFP not present.
431  return false;
432}
433
434bool Sema::CheckMipsBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
435  unsigned i = 0, l = 0, u = 0;
436  switch (BuiltinID) {
437  default: return false;
438  case Mips::BI__builtin_mips_wrdsp: i = 1; l = 0; u = 63; break;
439  case Mips::BI__builtin_mips_rddsp: i = 0; l = 0; u = 63; break;
440  case Mips::BI__builtin_mips_append: i = 2; l = 0; u = 31; break;
441  case Mips::BI__builtin_mips_balign: i = 2; l = 0; u = 3; break;
442  case Mips::BI__builtin_mips_precr_sra_ph_w: i = 2; l = 0; u = 31; break;
443  case Mips::BI__builtin_mips_precr_sra_r_ph_w: i = 2; l = 0; u = 31; break;
444  case Mips::BI__builtin_mips_prepend: i = 2; l = 0; u = 31; break;
445  };
446
447  // We can't check the value of a dependent argument.
448  if (TheCall->getArg(i)->isTypeDependent() ||
449      TheCall->getArg(i)->isValueDependent())
450    return false;
451
452  // Check that the immediate argument is actually a constant.
453  llvm::APSInt Result;
454  if (SemaBuiltinConstantArg(TheCall, i, Result))
455    return true;
456
457  // Range check against the upper/lower values for this instruction.
458  unsigned Val = Result.getZExtValue();
459  if (Val < l || Val > u)
460    return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
461      << l << u << TheCall->getArg(i)->getSourceRange();
462
463  return false;
464}
465
466/// Given a FunctionDecl's FormatAttr, attempts to populate the FomatStringInfo
467/// parameter with the FormatAttr's correct format_idx and firstDataArg.
468/// Returns true when the format fits the function and the FormatStringInfo has
469/// been populated.
470bool Sema::getFormatStringInfo(const FormatAttr *Format, bool IsCXXMember,
471                               FormatStringInfo *FSI) {
472  FSI->HasVAListArg = Format->getFirstArg() == 0;
473  FSI->FormatIdx = Format->getFormatIdx() - 1;
474  FSI->FirstDataArg = FSI->HasVAListArg ? 0 : Format->getFirstArg() - 1;
475
476  // The way the format attribute works in GCC, the implicit this argument
477  // of member functions is counted. However, it doesn't appear in our own
478  // lists, so decrement format_idx in that case.
479  if (IsCXXMember) {
480    if(FSI->FormatIdx == 0)
481      return false;
482    --FSI->FormatIdx;
483    if (FSI->FirstDataArg != 0)
484      --FSI->FirstDataArg;
485  }
486  return true;
487}
488
489/// Handles the checks for format strings, non-POD arguments to vararg
490/// functions, and NULL arguments passed to non-NULL parameters.
491void Sema::checkCall(NamedDecl *FDecl, Expr **Args,
492                     unsigned NumArgs,
493                     unsigned NumProtoArgs,
494                     bool IsMemberFunction,
495                     SourceLocation Loc,
496                     SourceRange Range,
497                     VariadicCallType CallType) {
498  if (CurContext->isDependentContext())
499    return;
500
501  // Printf and scanf checking.
502  bool HandledFormatString = false;
503  for (specific_attr_iterator<FormatAttr>
504         I = FDecl->specific_attr_begin<FormatAttr>(),
505         E = FDecl->specific_attr_end<FormatAttr>(); I != E ; ++I)
506    if (CheckFormatArguments(*I, Args, NumArgs, IsMemberFunction, CallType,
507                             Loc, Range))
508        HandledFormatString = true;
509
510  // Refuse POD arguments that weren't caught by the format string
511  // checks above.
512  if (!HandledFormatString && CallType != VariadicDoesNotApply)
513    for (unsigned ArgIdx = NumProtoArgs; ArgIdx < NumArgs; ++ArgIdx) {
514      // Args[ArgIdx] can be null in malformed code.
515      if (Expr *Arg = Args[ArgIdx])
516        variadicArgumentPODCheck(Arg, CallType);
517    }
518
519  for (specific_attr_iterator<NonNullAttr>
520         I = FDecl->specific_attr_begin<NonNullAttr>(),
521         E = FDecl->specific_attr_end<NonNullAttr>(); I != E; ++I)
522    CheckNonNullArguments(*I, Args, Loc);
523
524  // Type safety checking.
525  for (specific_attr_iterator<ArgumentWithTypeTagAttr>
526         i = FDecl->specific_attr_begin<ArgumentWithTypeTagAttr>(),
527         e = FDecl->specific_attr_end<ArgumentWithTypeTagAttr>(); i != e; ++i) {
528    CheckArgumentWithTypeTag(*i, Args);
529  }
530}
531
532/// CheckConstructorCall - Check a constructor call for correctness and safety
533/// properties not enforced by the C type system.
534void Sema::CheckConstructorCall(FunctionDecl *FDecl, Expr **Args,
535                                unsigned NumArgs,
536                                const FunctionProtoType *Proto,
537                                SourceLocation Loc) {
538  VariadicCallType CallType =
539    Proto->isVariadic() ? VariadicConstructor : VariadicDoesNotApply;
540  checkCall(FDecl, Args, NumArgs, Proto->getNumArgs(),
541            /*IsMemberFunction=*/true, Loc, SourceRange(), CallType);
542}
543
544/// CheckFunctionCall - Check a direct function call for various correctness
545/// and safety properties not strictly enforced by the C type system.
546bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall,
547                             const FunctionProtoType *Proto) {
548  bool IsMemberOperatorCall = isa<CXXOperatorCallExpr>(TheCall) &&
549                              isa<CXXMethodDecl>(FDecl);
550  bool IsMemberFunction = isa<CXXMemberCallExpr>(TheCall) ||
551                          IsMemberOperatorCall;
552  VariadicCallType CallType = getVariadicCallType(FDecl, Proto,
553                                                  TheCall->getCallee());
554  unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0;
555  Expr** Args = TheCall->getArgs();
556  unsigned NumArgs = TheCall->getNumArgs();
557  if (IsMemberOperatorCall) {
558    // If this is a call to a member operator, hide the first argument
559    // from checkCall.
560    // FIXME: Our choice of AST representation here is less than ideal.
561    ++Args;
562    --NumArgs;
563  }
564  checkCall(FDecl, Args, NumArgs, NumProtoArgs,
565            IsMemberFunction, TheCall->getRParenLoc(),
566            TheCall->getCallee()->getSourceRange(), CallType);
567
568  IdentifierInfo *FnInfo = FDecl->getIdentifier();
569  // None of the checks below are needed for functions that don't have
570  // simple names (e.g., C++ conversion functions).
571  if (!FnInfo)
572    return false;
573
574  unsigned CMId = FDecl->getMemoryFunctionKind();
575  if (CMId == 0)
576    return false;
577
578  // Handle memory setting and copying functions.
579  if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat)
580    CheckStrlcpycatArguments(TheCall, FnInfo);
581  else if (CMId == Builtin::BIstrncat)
582    CheckStrncatArguments(TheCall, FnInfo);
583  else
584    CheckMemaccessArguments(TheCall, CMId, FnInfo);
585
586  return false;
587}
588
589bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac,
590                               Expr **Args, unsigned NumArgs) {
591  VariadicCallType CallType =
592      Method->isVariadic() ? VariadicMethod : VariadicDoesNotApply;
593
594  checkCall(Method, Args, NumArgs, Method->param_size(),
595            /*IsMemberFunction=*/false,
596            lbrac, Method->getSourceRange(), CallType);
597
598  return false;
599}
600
601bool Sema::CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall,
602                          const FunctionProtoType *Proto) {
603  const VarDecl *V = dyn_cast<VarDecl>(NDecl);
604  if (!V)
605    return false;
606
607  QualType Ty = V->getType();
608  if (!Ty->isBlockPointerType())
609    return false;
610
611  VariadicCallType CallType =
612      Proto && Proto->isVariadic() ? VariadicBlock : VariadicDoesNotApply ;
613  unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0;
614
615  checkCall(NDecl, TheCall->getArgs(), TheCall->getNumArgs(),
616            NumProtoArgs, /*IsMemberFunction=*/false,
617            TheCall->getRParenLoc(),
618            TheCall->getCallee()->getSourceRange(), CallType);
619
620  return false;
621}
622
623ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult,
624                                         AtomicExpr::AtomicOp Op) {
625  CallExpr *TheCall = cast<CallExpr>(TheCallResult.get());
626  DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
627
628  // All these operations take one of the following forms:
629  enum {
630    // C    __c11_atomic_init(A *, C)
631    Init,
632    // C    __c11_atomic_load(A *, int)
633    Load,
634    // void __atomic_load(A *, CP, int)
635    Copy,
636    // C    __c11_atomic_add(A *, M, int)
637    Arithmetic,
638    // C    __atomic_exchange_n(A *, CP, int)
639    Xchg,
640    // void __atomic_exchange(A *, C *, CP, int)
641    GNUXchg,
642    // bool __c11_atomic_compare_exchange_strong(A *, C *, CP, int, int)
643    C11CmpXchg,
644    // bool __atomic_compare_exchange(A *, C *, CP, bool, int, int)
645    GNUCmpXchg
646  } Form = Init;
647  const unsigned NumArgs[] = { 2, 2, 3, 3, 3, 4, 5, 6 };
648  const unsigned NumVals[] = { 1, 0, 1, 1, 1, 2, 2, 3 };
649  // where:
650  //   C is an appropriate type,
651  //   A is volatile _Atomic(C) for __c11 builtins and is C for GNU builtins,
652  //   CP is C for __c11 builtins and GNU _n builtins and is C * otherwise,
653  //   M is C if C is an integer, and ptrdiff_t if C is a pointer, and
654  //   the int parameters are for orderings.
655
656  assert(AtomicExpr::AO__c11_atomic_init == 0 &&
657         AtomicExpr::AO__c11_atomic_fetch_xor + 1 == AtomicExpr::AO__atomic_load
658         && "need to update code for modified C11 atomics");
659  bool IsC11 = Op >= AtomicExpr::AO__c11_atomic_init &&
660               Op <= AtomicExpr::AO__c11_atomic_fetch_xor;
661  bool IsN = Op == AtomicExpr::AO__atomic_load_n ||
662             Op == AtomicExpr::AO__atomic_store_n ||
663             Op == AtomicExpr::AO__atomic_exchange_n ||
664             Op == AtomicExpr::AO__atomic_compare_exchange_n;
665  bool IsAddSub = false;
666
667  switch (Op) {
668  case AtomicExpr::AO__c11_atomic_init:
669    Form = Init;
670    break;
671
672  case AtomicExpr::AO__c11_atomic_load:
673  case AtomicExpr::AO__atomic_load_n:
674    Form = Load;
675    break;
676
677  case AtomicExpr::AO__c11_atomic_store:
678  case AtomicExpr::AO__atomic_load:
679  case AtomicExpr::AO__atomic_store:
680  case AtomicExpr::AO__atomic_store_n:
681    Form = Copy;
682    break;
683
684  case AtomicExpr::AO__c11_atomic_fetch_add:
685  case AtomicExpr::AO__c11_atomic_fetch_sub:
686  case AtomicExpr::AO__atomic_fetch_add:
687  case AtomicExpr::AO__atomic_fetch_sub:
688  case AtomicExpr::AO__atomic_add_fetch:
689  case AtomicExpr::AO__atomic_sub_fetch:
690    IsAddSub = true;
691    // Fall through.
692  case AtomicExpr::AO__c11_atomic_fetch_and:
693  case AtomicExpr::AO__c11_atomic_fetch_or:
694  case AtomicExpr::AO__c11_atomic_fetch_xor:
695  case AtomicExpr::AO__atomic_fetch_and:
696  case AtomicExpr::AO__atomic_fetch_or:
697  case AtomicExpr::AO__atomic_fetch_xor:
698  case AtomicExpr::AO__atomic_fetch_nand:
699  case AtomicExpr::AO__atomic_and_fetch:
700  case AtomicExpr::AO__atomic_or_fetch:
701  case AtomicExpr::AO__atomic_xor_fetch:
702  case AtomicExpr::AO__atomic_nand_fetch:
703    Form = Arithmetic;
704    break;
705
706  case AtomicExpr::AO__c11_atomic_exchange:
707  case AtomicExpr::AO__atomic_exchange_n:
708    Form = Xchg;
709    break;
710
711  case AtomicExpr::AO__atomic_exchange:
712    Form = GNUXchg;
713    break;
714
715  case AtomicExpr::AO__c11_atomic_compare_exchange_strong:
716  case AtomicExpr::AO__c11_atomic_compare_exchange_weak:
717    Form = C11CmpXchg;
718    break;
719
720  case AtomicExpr::AO__atomic_compare_exchange:
721  case AtomicExpr::AO__atomic_compare_exchange_n:
722    Form = GNUCmpXchg;
723    break;
724  }
725
726  // Check we have the right number of arguments.
727  if (TheCall->getNumArgs() < NumArgs[Form]) {
728    Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
729      << 0 << NumArgs[Form] << TheCall->getNumArgs()
730      << TheCall->getCallee()->getSourceRange();
731    return ExprError();
732  } else if (TheCall->getNumArgs() > NumArgs[Form]) {
733    Diag(TheCall->getArg(NumArgs[Form])->getLocStart(),
734         diag::err_typecheck_call_too_many_args)
735      << 0 << NumArgs[Form] << TheCall->getNumArgs()
736      << TheCall->getCallee()->getSourceRange();
737    return ExprError();
738  }
739
740  // Inspect the first argument of the atomic operation.
741  Expr *Ptr = TheCall->getArg(0);
742  Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get();
743  const PointerType *pointerType = Ptr->getType()->getAs<PointerType>();
744  if (!pointerType) {
745    Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
746      << Ptr->getType() << Ptr->getSourceRange();
747    return ExprError();
748  }
749
750  // For a __c11 builtin, this should be a pointer to an _Atomic type.
751  QualType AtomTy = pointerType->getPointeeType(); // 'A'
752  QualType ValType = AtomTy; // 'C'
753  if (IsC11) {
754    if (!AtomTy->isAtomicType()) {
755      Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic)
756        << Ptr->getType() << Ptr->getSourceRange();
757      return ExprError();
758    }
759    if (AtomTy.isConstQualified()) {
760      Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_atomic)
761        << Ptr->getType() << Ptr->getSourceRange();
762      return ExprError();
763    }
764    ValType = AtomTy->getAs<AtomicType>()->getValueType();
765  }
766
767  // For an arithmetic operation, the implied arithmetic must be well-formed.
768  if (Form == Arithmetic) {
769    // gcc does not enforce these rules for GNU atomics, but we do so for sanity.
770    if (IsAddSub && !ValType->isIntegerType() && !ValType->isPointerType()) {
771      Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr)
772        << IsC11 << Ptr->getType() << Ptr->getSourceRange();
773      return ExprError();
774    }
775    if (!IsAddSub && !ValType->isIntegerType()) {
776      Diag(DRE->getLocStart(), diag::err_atomic_op_bitwise_needs_atomic_int)
777        << IsC11 << Ptr->getType() << Ptr->getSourceRange();
778      return ExprError();
779    }
780  } else if (IsN && !ValType->isIntegerType() && !ValType->isPointerType()) {
781    // For __atomic_*_n operations, the value type must be a scalar integral or
782    // pointer type which is 1, 2, 4, 8 or 16 bytes in length.
783    Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr)
784      << IsC11 << Ptr->getType() << Ptr->getSourceRange();
785    return ExprError();
786  }
787
788  if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context)) {
789    // For GNU atomics, require a trivially-copyable type. This is not part of
790    // the GNU atomics specification, but we enforce it for sanity.
791    Diag(DRE->getLocStart(), diag::err_atomic_op_needs_trivial_copy)
792      << Ptr->getType() << Ptr->getSourceRange();
793    return ExprError();
794  }
795
796  // FIXME: For any builtin other than a load, the ValType must not be
797  // const-qualified.
798
799  switch (ValType.getObjCLifetime()) {
800  case Qualifiers::OCL_None:
801  case Qualifiers::OCL_ExplicitNone:
802    // okay
803    break;
804
805  case Qualifiers::OCL_Weak:
806  case Qualifiers::OCL_Strong:
807  case Qualifiers::OCL_Autoreleasing:
808    // FIXME: Can this happen? By this point, ValType should be known
809    // to be trivially copyable.
810    Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
811      << ValType << Ptr->getSourceRange();
812    return ExprError();
813  }
814
815  QualType ResultType = ValType;
816  if (Form == Copy || Form == GNUXchg || Form == Init)
817    ResultType = Context.VoidTy;
818  else if (Form == C11CmpXchg || Form == GNUCmpXchg)
819    ResultType = Context.BoolTy;
820
821  // The type of a parameter passed 'by value'. In the GNU atomics, such
822  // arguments are actually passed as pointers.
823  QualType ByValType = ValType; // 'CP'
824  if (!IsC11 && !IsN)
825    ByValType = Ptr->getType();
826
827  // The first argument --- the pointer --- has a fixed type; we
828  // deduce the types of the rest of the arguments accordingly.  Walk
829  // the remaining arguments, converting them to the deduced value type.
830  for (unsigned i = 1; i != NumArgs[Form]; ++i) {
831    QualType Ty;
832    if (i < NumVals[Form] + 1) {
833      switch (i) {
834      case 1:
835        // The second argument is the non-atomic operand. For arithmetic, this
836        // is always passed by value, and for a compare_exchange it is always
837        // passed by address. For the rest, GNU uses by-address and C11 uses
838        // by-value.
839        assert(Form != Load);
840        if (Form == Init || (Form == Arithmetic && ValType->isIntegerType()))
841          Ty = ValType;
842        else if (Form == Copy || Form == Xchg)
843          Ty = ByValType;
844        else if (Form == Arithmetic)
845          Ty = Context.getPointerDiffType();
846        else
847          Ty = Context.getPointerType(ValType.getUnqualifiedType());
848        break;
849      case 2:
850        // The third argument to compare_exchange / GNU exchange is a
851        // (pointer to a) desired value.
852        Ty = ByValType;
853        break;
854      case 3:
855        // The fourth argument to GNU compare_exchange is a 'weak' flag.
856        Ty = Context.BoolTy;
857        break;
858      }
859    } else {
860      // The order(s) are always converted to int.
861      Ty = Context.IntTy;
862    }
863
864    InitializedEntity Entity =
865        InitializedEntity::InitializeParameter(Context, Ty, false);
866    ExprResult Arg = TheCall->getArg(i);
867    Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
868    if (Arg.isInvalid())
869      return true;
870    TheCall->setArg(i, Arg.get());
871  }
872
873  // Permute the arguments into a 'consistent' order.
874  SmallVector<Expr*, 5> SubExprs;
875  SubExprs.push_back(Ptr);
876  switch (Form) {
877  case Init:
878    // Note, AtomicExpr::getVal1() has a special case for this atomic.
879    SubExprs.push_back(TheCall->getArg(1)); // Val1
880    break;
881  case Load:
882    SubExprs.push_back(TheCall->getArg(1)); // Order
883    break;
884  case Copy:
885  case Arithmetic:
886  case Xchg:
887    SubExprs.push_back(TheCall->getArg(2)); // Order
888    SubExprs.push_back(TheCall->getArg(1)); // Val1
889    break;
890  case GNUXchg:
891    // Note, AtomicExpr::getVal2() has a special case for this atomic.
892    SubExprs.push_back(TheCall->getArg(3)); // Order
893    SubExprs.push_back(TheCall->getArg(1)); // Val1
894    SubExprs.push_back(TheCall->getArg(2)); // Val2
895    break;
896  case C11CmpXchg:
897    SubExprs.push_back(TheCall->getArg(3)); // Order
898    SubExprs.push_back(TheCall->getArg(1)); // Val1
899    SubExprs.push_back(TheCall->getArg(4)); // OrderFail
900    SubExprs.push_back(TheCall->getArg(2)); // Val2
901    break;
902  case GNUCmpXchg:
903    SubExprs.push_back(TheCall->getArg(4)); // Order
904    SubExprs.push_back(TheCall->getArg(1)); // Val1
905    SubExprs.push_back(TheCall->getArg(5)); // OrderFail
906    SubExprs.push_back(TheCall->getArg(2)); // Val2
907    SubExprs.push_back(TheCall->getArg(3)); // Weak
908    break;
909  }
910
911  return Owned(new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(),
912                                        SubExprs, ResultType, Op,
913                                        TheCall->getRParenLoc()));
914}
915
916
917/// checkBuiltinArgument - Given a call to a builtin function, perform
918/// normal type-checking on the given argument, updating the call in
919/// place.  This is useful when a builtin function requires custom
920/// type-checking for some of its arguments but not necessarily all of
921/// them.
922///
923/// Returns true on error.
924static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) {
925  FunctionDecl *Fn = E->getDirectCallee();
926  assert(Fn && "builtin call without direct callee!");
927
928  ParmVarDecl *Param = Fn->getParamDecl(ArgIndex);
929  InitializedEntity Entity =
930    InitializedEntity::InitializeParameter(S.Context, Param);
931
932  ExprResult Arg = E->getArg(0);
933  Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg);
934  if (Arg.isInvalid())
935    return true;
936
937  E->setArg(ArgIndex, Arg.take());
938  return false;
939}
940
941/// SemaBuiltinAtomicOverloaded - We have a call to a function like
942/// __sync_fetch_and_add, which is an overloaded function based on the pointer
943/// type of its first argument.  The main ActOnCallExpr routines have already
944/// promoted the types of arguments because all of these calls are prototyped as
945/// void(...).
946///
947/// This function goes through and does final semantic checking for these
948/// builtins,
949ExprResult
950Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) {
951  CallExpr *TheCall = (CallExpr *)TheCallResult.get();
952  DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
953  FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
954
955  // Ensure that we have at least one argument to do type inference from.
956  if (TheCall->getNumArgs() < 1) {
957    Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
958      << 0 << 1 << TheCall->getNumArgs()
959      << TheCall->getCallee()->getSourceRange();
960    return ExprError();
961  }
962
963  // Inspect the first argument of the atomic builtin.  This should always be
964  // a pointer type, whose element is an integral scalar or pointer type.
965  // Because it is a pointer type, we don't have to worry about any implicit
966  // casts here.
967  // FIXME: We don't allow floating point scalars as input.
968  Expr *FirstArg = TheCall->getArg(0);
969  ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg);
970  if (FirstArgResult.isInvalid())
971    return ExprError();
972  FirstArg = FirstArgResult.take();
973  TheCall->setArg(0, FirstArg);
974
975  const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>();
976  if (!pointerType) {
977    Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
978      << FirstArg->getType() << FirstArg->getSourceRange();
979    return ExprError();
980  }
981
982  QualType ValType = pointerType->getPointeeType();
983  if (!ValType->isIntegerType() && !ValType->isAnyPointerType() &&
984      !ValType->isBlockPointerType()) {
985    Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr)
986      << FirstArg->getType() << FirstArg->getSourceRange();
987    return ExprError();
988  }
989
990  switch (ValType.getObjCLifetime()) {
991  case Qualifiers::OCL_None:
992  case Qualifiers::OCL_ExplicitNone:
993    // okay
994    break;
995
996  case Qualifiers::OCL_Weak:
997  case Qualifiers::OCL_Strong:
998  case Qualifiers::OCL_Autoreleasing:
999    Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
1000      << ValType << FirstArg->getSourceRange();
1001    return ExprError();
1002  }
1003
1004  // Strip any qualifiers off ValType.
1005  ValType = ValType.getUnqualifiedType();
1006
1007  // The majority of builtins return a value, but a few have special return
1008  // types, so allow them to override appropriately below.
1009  QualType ResultType = ValType;
1010
1011  // We need to figure out which concrete builtin this maps onto.  For example,
1012  // __sync_fetch_and_add with a 2 byte object turns into
1013  // __sync_fetch_and_add_2.
1014#define BUILTIN_ROW(x) \
1015  { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \
1016    Builtin::BI##x##_8, Builtin::BI##x##_16 }
1017
1018  static const unsigned BuiltinIndices[][5] = {
1019    BUILTIN_ROW(__sync_fetch_and_add),
1020    BUILTIN_ROW(__sync_fetch_and_sub),
1021    BUILTIN_ROW(__sync_fetch_and_or),
1022    BUILTIN_ROW(__sync_fetch_and_and),
1023    BUILTIN_ROW(__sync_fetch_and_xor),
1024
1025    BUILTIN_ROW(__sync_add_and_fetch),
1026    BUILTIN_ROW(__sync_sub_and_fetch),
1027    BUILTIN_ROW(__sync_and_and_fetch),
1028    BUILTIN_ROW(__sync_or_and_fetch),
1029    BUILTIN_ROW(__sync_xor_and_fetch),
1030
1031    BUILTIN_ROW(__sync_val_compare_and_swap),
1032    BUILTIN_ROW(__sync_bool_compare_and_swap),
1033    BUILTIN_ROW(__sync_lock_test_and_set),
1034    BUILTIN_ROW(__sync_lock_release),
1035    BUILTIN_ROW(__sync_swap)
1036  };
1037#undef BUILTIN_ROW
1038
1039  // Determine the index of the size.
1040  unsigned SizeIndex;
1041  switch (Context.getTypeSizeInChars(ValType).getQuantity()) {
1042  case 1: SizeIndex = 0; break;
1043  case 2: SizeIndex = 1; break;
1044  case 4: SizeIndex = 2; break;
1045  case 8: SizeIndex = 3; break;
1046  case 16: SizeIndex = 4; break;
1047  default:
1048    Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size)
1049      << FirstArg->getType() << FirstArg->getSourceRange();
1050    return ExprError();
1051  }
1052
1053  // Each of these builtins has one pointer argument, followed by some number of
1054  // values (0, 1 or 2) followed by a potentially empty varags list of stuff
1055  // that we ignore.  Find out which row of BuiltinIndices to read from as well
1056  // as the number of fixed args.
1057  unsigned BuiltinID = FDecl->getBuiltinID();
1058  unsigned BuiltinIndex, NumFixed = 1;
1059  switch (BuiltinID) {
1060  default: llvm_unreachable("Unknown overloaded atomic builtin!");
1061  case Builtin::BI__sync_fetch_and_add:
1062  case Builtin::BI__sync_fetch_and_add_1:
1063  case Builtin::BI__sync_fetch_and_add_2:
1064  case Builtin::BI__sync_fetch_and_add_4:
1065  case Builtin::BI__sync_fetch_and_add_8:
1066  case Builtin::BI__sync_fetch_and_add_16:
1067    BuiltinIndex = 0;
1068    break;
1069
1070  case Builtin::BI__sync_fetch_and_sub:
1071  case Builtin::BI__sync_fetch_and_sub_1:
1072  case Builtin::BI__sync_fetch_and_sub_2:
1073  case Builtin::BI__sync_fetch_and_sub_4:
1074  case Builtin::BI__sync_fetch_and_sub_8:
1075  case Builtin::BI__sync_fetch_and_sub_16:
1076    BuiltinIndex = 1;
1077    break;
1078
1079  case Builtin::BI__sync_fetch_and_or:
1080  case Builtin::BI__sync_fetch_and_or_1:
1081  case Builtin::BI__sync_fetch_and_or_2:
1082  case Builtin::BI__sync_fetch_and_or_4:
1083  case Builtin::BI__sync_fetch_and_or_8:
1084  case Builtin::BI__sync_fetch_and_or_16:
1085    BuiltinIndex = 2;
1086    break;
1087
1088  case Builtin::BI__sync_fetch_and_and:
1089  case Builtin::BI__sync_fetch_and_and_1:
1090  case Builtin::BI__sync_fetch_and_and_2:
1091  case Builtin::BI__sync_fetch_and_and_4:
1092  case Builtin::BI__sync_fetch_and_and_8:
1093  case Builtin::BI__sync_fetch_and_and_16:
1094    BuiltinIndex = 3;
1095    break;
1096
1097  case Builtin::BI__sync_fetch_and_xor:
1098  case Builtin::BI__sync_fetch_and_xor_1:
1099  case Builtin::BI__sync_fetch_and_xor_2:
1100  case Builtin::BI__sync_fetch_and_xor_4:
1101  case Builtin::BI__sync_fetch_and_xor_8:
1102  case Builtin::BI__sync_fetch_and_xor_16:
1103    BuiltinIndex = 4;
1104    break;
1105
1106  case Builtin::BI__sync_add_and_fetch:
1107  case Builtin::BI__sync_add_and_fetch_1:
1108  case Builtin::BI__sync_add_and_fetch_2:
1109  case Builtin::BI__sync_add_and_fetch_4:
1110  case Builtin::BI__sync_add_and_fetch_8:
1111  case Builtin::BI__sync_add_and_fetch_16:
1112    BuiltinIndex = 5;
1113    break;
1114
1115  case Builtin::BI__sync_sub_and_fetch:
1116  case Builtin::BI__sync_sub_and_fetch_1:
1117  case Builtin::BI__sync_sub_and_fetch_2:
1118  case Builtin::BI__sync_sub_and_fetch_4:
1119  case Builtin::BI__sync_sub_and_fetch_8:
1120  case Builtin::BI__sync_sub_and_fetch_16:
1121    BuiltinIndex = 6;
1122    break;
1123
1124  case Builtin::BI__sync_and_and_fetch:
1125  case Builtin::BI__sync_and_and_fetch_1:
1126  case Builtin::BI__sync_and_and_fetch_2:
1127  case Builtin::BI__sync_and_and_fetch_4:
1128  case Builtin::BI__sync_and_and_fetch_8:
1129  case Builtin::BI__sync_and_and_fetch_16:
1130    BuiltinIndex = 7;
1131    break;
1132
1133  case Builtin::BI__sync_or_and_fetch:
1134  case Builtin::BI__sync_or_and_fetch_1:
1135  case Builtin::BI__sync_or_and_fetch_2:
1136  case Builtin::BI__sync_or_and_fetch_4:
1137  case Builtin::BI__sync_or_and_fetch_8:
1138  case Builtin::BI__sync_or_and_fetch_16:
1139    BuiltinIndex = 8;
1140    break;
1141
1142  case Builtin::BI__sync_xor_and_fetch:
1143  case Builtin::BI__sync_xor_and_fetch_1:
1144  case Builtin::BI__sync_xor_and_fetch_2:
1145  case Builtin::BI__sync_xor_and_fetch_4:
1146  case Builtin::BI__sync_xor_and_fetch_8:
1147  case Builtin::BI__sync_xor_and_fetch_16:
1148    BuiltinIndex = 9;
1149    break;
1150
1151  case Builtin::BI__sync_val_compare_and_swap:
1152  case Builtin::BI__sync_val_compare_and_swap_1:
1153  case Builtin::BI__sync_val_compare_and_swap_2:
1154  case Builtin::BI__sync_val_compare_and_swap_4:
1155  case Builtin::BI__sync_val_compare_and_swap_8:
1156  case Builtin::BI__sync_val_compare_and_swap_16:
1157    BuiltinIndex = 10;
1158    NumFixed = 2;
1159    break;
1160
1161  case Builtin::BI__sync_bool_compare_and_swap:
1162  case Builtin::BI__sync_bool_compare_and_swap_1:
1163  case Builtin::BI__sync_bool_compare_and_swap_2:
1164  case Builtin::BI__sync_bool_compare_and_swap_4:
1165  case Builtin::BI__sync_bool_compare_and_swap_8:
1166  case Builtin::BI__sync_bool_compare_and_swap_16:
1167    BuiltinIndex = 11;
1168    NumFixed = 2;
1169    ResultType = Context.BoolTy;
1170    break;
1171
1172  case Builtin::BI__sync_lock_test_and_set:
1173  case Builtin::BI__sync_lock_test_and_set_1:
1174  case Builtin::BI__sync_lock_test_and_set_2:
1175  case Builtin::BI__sync_lock_test_and_set_4:
1176  case Builtin::BI__sync_lock_test_and_set_8:
1177  case Builtin::BI__sync_lock_test_and_set_16:
1178    BuiltinIndex = 12;
1179    break;
1180
1181  case Builtin::BI__sync_lock_release:
1182  case Builtin::BI__sync_lock_release_1:
1183  case Builtin::BI__sync_lock_release_2:
1184  case Builtin::BI__sync_lock_release_4:
1185  case Builtin::BI__sync_lock_release_8:
1186  case Builtin::BI__sync_lock_release_16:
1187    BuiltinIndex = 13;
1188    NumFixed = 0;
1189    ResultType = Context.VoidTy;
1190    break;
1191
1192  case Builtin::BI__sync_swap:
1193  case Builtin::BI__sync_swap_1:
1194  case Builtin::BI__sync_swap_2:
1195  case Builtin::BI__sync_swap_4:
1196  case Builtin::BI__sync_swap_8:
1197  case Builtin::BI__sync_swap_16:
1198    BuiltinIndex = 14;
1199    break;
1200  }
1201
1202  // Now that we know how many fixed arguments we expect, first check that we
1203  // have at least that many.
1204  if (TheCall->getNumArgs() < 1+NumFixed) {
1205    Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
1206      << 0 << 1+NumFixed << TheCall->getNumArgs()
1207      << TheCall->getCallee()->getSourceRange();
1208    return ExprError();
1209  }
1210
1211  // Get the decl for the concrete builtin from this, we can tell what the
1212  // concrete integer type we should convert to is.
1213  unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex];
1214  const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID);
1215  FunctionDecl *NewBuiltinDecl;
1216  if (NewBuiltinID == BuiltinID)
1217    NewBuiltinDecl = FDecl;
1218  else {
1219    // Perform builtin lookup to avoid redeclaring it.
1220    DeclarationName DN(&Context.Idents.get(NewBuiltinName));
1221    LookupResult Res(*this, DN, DRE->getLocStart(), LookupOrdinaryName);
1222    LookupName(Res, TUScope, /*AllowBuiltinCreation=*/true);
1223    assert(Res.getFoundDecl());
1224    NewBuiltinDecl = dyn_cast<FunctionDecl>(Res.getFoundDecl());
1225    if (NewBuiltinDecl == 0)
1226      return ExprError();
1227  }
1228
1229  // The first argument --- the pointer --- has a fixed type; we
1230  // deduce the types of the rest of the arguments accordingly.  Walk
1231  // the remaining arguments, converting them to the deduced value type.
1232  for (unsigned i = 0; i != NumFixed; ++i) {
1233    ExprResult Arg = TheCall->getArg(i+1);
1234
1235    // GCC does an implicit conversion to the pointer or integer ValType.  This
1236    // can fail in some cases (1i -> int**), check for this error case now.
1237    // Initialize the argument.
1238    InitializedEntity Entity = InitializedEntity::InitializeParameter(Context,
1239                                                   ValType, /*consume*/ false);
1240    Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
1241    if (Arg.isInvalid())
1242      return ExprError();
1243
1244    // Okay, we have something that *can* be converted to the right type.  Check
1245    // to see if there is a potentially weird extension going on here.  This can
1246    // happen when you do an atomic operation on something like an char* and
1247    // pass in 42.  The 42 gets converted to char.  This is even more strange
1248    // for things like 45.123 -> char, etc.
1249    // FIXME: Do this check.
1250    TheCall->setArg(i+1, Arg.take());
1251  }
1252
1253  ASTContext& Context = this->getASTContext();
1254
1255  // Create a new DeclRefExpr to refer to the new decl.
1256  DeclRefExpr* NewDRE = DeclRefExpr::Create(
1257      Context,
1258      DRE->getQualifierLoc(),
1259      SourceLocation(),
1260      NewBuiltinDecl,
1261      /*enclosing*/ false,
1262      DRE->getLocation(),
1263      Context.BuiltinFnTy,
1264      DRE->getValueKind());
1265
1266  // Set the callee in the CallExpr.
1267  // FIXME: This loses syntactic information.
1268  QualType CalleePtrTy = Context.getPointerType(NewBuiltinDecl->getType());
1269  ExprResult PromotedCall = ImpCastExprToType(NewDRE, CalleePtrTy,
1270                                              CK_BuiltinFnToFnPtr);
1271  TheCall->setCallee(PromotedCall.take());
1272
1273  // Change the result type of the call to match the original value type. This
1274  // is arbitrary, but the codegen for these builtins ins design to handle it
1275  // gracefully.
1276  TheCall->setType(ResultType);
1277
1278  return TheCallResult;
1279}
1280
1281/// CheckObjCString - Checks that the argument to the builtin
1282/// CFString constructor is correct
1283/// Note: It might also make sense to do the UTF-16 conversion here (would
1284/// simplify the backend).
1285bool Sema::CheckObjCString(Expr *Arg) {
1286  Arg = Arg->IgnoreParenCasts();
1287  StringLiteral *Literal = dyn_cast<StringLiteral>(Arg);
1288
1289  if (!Literal || !Literal->isAscii()) {
1290    Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant)
1291      << Arg->getSourceRange();
1292    return true;
1293  }
1294
1295  if (Literal->containsNonAsciiOrNull()) {
1296    StringRef String = Literal->getString();
1297    unsigned NumBytes = String.size();
1298    SmallVector<UTF16, 128> ToBuf(NumBytes);
1299    const UTF8 *FromPtr = (const UTF8 *)String.data();
1300    UTF16 *ToPtr = &ToBuf[0];
1301
1302    ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes,
1303                                                 &ToPtr, ToPtr + NumBytes,
1304                                                 strictConversion);
1305    // Check for conversion failure.
1306    if (Result != conversionOK)
1307      Diag(Arg->getLocStart(),
1308           diag::warn_cfstring_truncated) << Arg->getSourceRange();
1309  }
1310  return false;
1311}
1312
1313/// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity.
1314/// Emit an error and return true on failure, return false on success.
1315bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) {
1316  Expr *Fn = TheCall->getCallee();
1317  if (TheCall->getNumArgs() > 2) {
1318    Diag(TheCall->getArg(2)->getLocStart(),
1319         diag::err_typecheck_call_too_many_args)
1320      << 0 /*function call*/ << 2 << TheCall->getNumArgs()
1321      << Fn->getSourceRange()
1322      << SourceRange(TheCall->getArg(2)->getLocStart(),
1323                     (*(TheCall->arg_end()-1))->getLocEnd());
1324    return true;
1325  }
1326
1327  if (TheCall->getNumArgs() < 2) {
1328    return Diag(TheCall->getLocEnd(),
1329      diag::err_typecheck_call_too_few_args_at_least)
1330      << 0 /*function call*/ << 2 << TheCall->getNumArgs();
1331  }
1332
1333  // Type-check the first argument normally.
1334  if (checkBuiltinArgument(*this, TheCall, 0))
1335    return true;
1336
1337  // Determine whether the current function is variadic or not.
1338  BlockScopeInfo *CurBlock = getCurBlock();
1339  bool isVariadic;
1340  if (CurBlock)
1341    isVariadic = CurBlock->TheDecl->isVariadic();
1342  else if (FunctionDecl *FD = getCurFunctionDecl())
1343    isVariadic = FD->isVariadic();
1344  else
1345    isVariadic = getCurMethodDecl()->isVariadic();
1346
1347  if (!isVariadic) {
1348    Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function);
1349    return true;
1350  }
1351
1352  // Verify that the second argument to the builtin is the last argument of the
1353  // current function or method.
1354  bool SecondArgIsLastNamedArgument = false;
1355  const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts();
1356
1357  if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) {
1358    if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) {
1359      // FIXME: This isn't correct for methods (results in bogus warning).
1360      // Get the last formal in the current function.
1361      const ParmVarDecl *LastArg;
1362      if (CurBlock)
1363        LastArg = *(CurBlock->TheDecl->param_end()-1);
1364      else if (FunctionDecl *FD = getCurFunctionDecl())
1365        LastArg = *(FD->param_end()-1);
1366      else
1367        LastArg = *(getCurMethodDecl()->param_end()-1);
1368      SecondArgIsLastNamedArgument = PV == LastArg;
1369    }
1370  }
1371
1372  if (!SecondArgIsLastNamedArgument)
1373    Diag(TheCall->getArg(1)->getLocStart(),
1374         diag::warn_second_parameter_of_va_start_not_last_named_argument);
1375  return false;
1376}
1377
1378/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and
1379/// friends.  This is declared to take (...), so we have to check everything.
1380bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) {
1381  if (TheCall->getNumArgs() < 2)
1382    return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
1383      << 0 << 2 << TheCall->getNumArgs()/*function call*/;
1384  if (TheCall->getNumArgs() > 2)
1385    return Diag(TheCall->getArg(2)->getLocStart(),
1386                diag::err_typecheck_call_too_many_args)
1387      << 0 /*function call*/ << 2 << TheCall->getNumArgs()
1388      << SourceRange(TheCall->getArg(2)->getLocStart(),
1389                     (*(TheCall->arg_end()-1))->getLocEnd());
1390
1391  ExprResult OrigArg0 = TheCall->getArg(0);
1392  ExprResult OrigArg1 = TheCall->getArg(1);
1393
1394  // Do standard promotions between the two arguments, returning their common
1395  // type.
1396  QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false);
1397  if (OrigArg0.isInvalid() || OrigArg1.isInvalid())
1398    return true;
1399
1400  // Make sure any conversions are pushed back into the call; this is
1401  // type safe since unordered compare builtins are declared as "_Bool
1402  // foo(...)".
1403  TheCall->setArg(0, OrigArg0.get());
1404  TheCall->setArg(1, OrigArg1.get());
1405
1406  if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent())
1407    return false;
1408
1409  // If the common type isn't a real floating type, then the arguments were
1410  // invalid for this operation.
1411  if (Res.isNull() || !Res->isRealFloatingType())
1412    return Diag(OrigArg0.get()->getLocStart(),
1413                diag::err_typecheck_call_invalid_ordered_compare)
1414      << OrigArg0.get()->getType() << OrigArg1.get()->getType()
1415      << SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd());
1416
1417  return false;
1418}
1419
1420/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like
1421/// __builtin_isnan and friends.  This is declared to take (...), so we have
1422/// to check everything. We expect the last argument to be a floating point
1423/// value.
1424bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) {
1425  if (TheCall->getNumArgs() < NumArgs)
1426    return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
1427      << 0 << NumArgs << TheCall->getNumArgs()/*function call*/;
1428  if (TheCall->getNumArgs() > NumArgs)
1429    return Diag(TheCall->getArg(NumArgs)->getLocStart(),
1430                diag::err_typecheck_call_too_many_args)
1431      << 0 /*function call*/ << NumArgs << TheCall->getNumArgs()
1432      << SourceRange(TheCall->getArg(NumArgs)->getLocStart(),
1433                     (*(TheCall->arg_end()-1))->getLocEnd());
1434
1435  Expr *OrigArg = TheCall->getArg(NumArgs-1);
1436
1437  if (OrigArg->isTypeDependent())
1438    return false;
1439
1440  // This operation requires a non-_Complex floating-point number.
1441  if (!OrigArg->getType()->isRealFloatingType())
1442    return Diag(OrigArg->getLocStart(),
1443                diag::err_typecheck_call_invalid_unary_fp)
1444      << OrigArg->getType() << OrigArg->getSourceRange();
1445
1446  // If this is an implicit conversion from float -> double, remove it.
1447  if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) {
1448    Expr *CastArg = Cast->getSubExpr();
1449    if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) {
1450      assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) &&
1451             "promotion from float to double is the only expected cast here");
1452      Cast->setSubExpr(0);
1453      TheCall->setArg(NumArgs-1, CastArg);
1454    }
1455  }
1456
1457  return false;
1458}
1459
1460/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector.
1461// This is declared to take (...), so we have to check everything.
1462ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) {
1463  if (TheCall->getNumArgs() < 2)
1464    return ExprError(Diag(TheCall->getLocEnd(),
1465                          diag::err_typecheck_call_too_few_args_at_least)
1466      << 0 /*function call*/ << 2 << TheCall->getNumArgs()
1467      << TheCall->getSourceRange());
1468
1469  // Determine which of the following types of shufflevector we're checking:
1470  // 1) unary, vector mask: (lhs, mask)
1471  // 2) binary, vector mask: (lhs, rhs, mask)
1472  // 3) binary, scalar mask: (lhs, rhs, index, ..., index)
1473  QualType resType = TheCall->getArg(0)->getType();
1474  unsigned numElements = 0;
1475
1476  if (!TheCall->getArg(0)->isTypeDependent() &&
1477      !TheCall->getArg(1)->isTypeDependent()) {
1478    QualType LHSType = TheCall->getArg(0)->getType();
1479    QualType RHSType = TheCall->getArg(1)->getType();
1480
1481    if (!LHSType->isVectorType() || !RHSType->isVectorType()) {
1482      Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector)
1483        << SourceRange(TheCall->getArg(0)->getLocStart(),
1484                       TheCall->getArg(1)->getLocEnd());
1485      return ExprError();
1486    }
1487
1488    numElements = LHSType->getAs<VectorType>()->getNumElements();
1489    unsigned numResElements = TheCall->getNumArgs() - 2;
1490
1491    // Check to see if we have a call with 2 vector arguments, the unary shuffle
1492    // with mask.  If so, verify that RHS is an integer vector type with the
1493    // same number of elts as lhs.
1494    if (TheCall->getNumArgs() == 2) {
1495      if (!RHSType->hasIntegerRepresentation() ||
1496          RHSType->getAs<VectorType>()->getNumElements() != numElements)
1497        Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector)
1498          << SourceRange(TheCall->getArg(1)->getLocStart(),
1499                         TheCall->getArg(1)->getLocEnd());
1500      numResElements = numElements;
1501    }
1502    else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) {
1503      Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector)
1504        << SourceRange(TheCall->getArg(0)->getLocStart(),
1505                       TheCall->getArg(1)->getLocEnd());
1506      return ExprError();
1507    } else if (numElements != numResElements) {
1508      QualType eltType = LHSType->getAs<VectorType>()->getElementType();
1509      resType = Context.getVectorType(eltType, numResElements,
1510                                      VectorType::GenericVector);
1511    }
1512  }
1513
1514  for (unsigned i = 2; i < TheCall->getNumArgs(); i++) {
1515    if (TheCall->getArg(i)->isTypeDependent() ||
1516        TheCall->getArg(i)->isValueDependent())
1517      continue;
1518
1519    llvm::APSInt Result(32);
1520    if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context))
1521      return ExprError(Diag(TheCall->getLocStart(),
1522                  diag::err_shufflevector_nonconstant_argument)
1523                << TheCall->getArg(i)->getSourceRange());
1524
1525    if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2)
1526      return ExprError(Diag(TheCall->getLocStart(),
1527                  diag::err_shufflevector_argument_too_large)
1528               << TheCall->getArg(i)->getSourceRange());
1529  }
1530
1531  SmallVector<Expr*, 32> exprs;
1532
1533  for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) {
1534    exprs.push_back(TheCall->getArg(i));
1535    TheCall->setArg(i, 0);
1536  }
1537
1538  return Owned(new (Context) ShuffleVectorExpr(Context, exprs, resType,
1539                                            TheCall->getCallee()->getLocStart(),
1540                                            TheCall->getRParenLoc()));
1541}
1542
1543/// SemaBuiltinPrefetch - Handle __builtin_prefetch.
1544// This is declared to take (const void*, ...) and can take two
1545// optional constant int args.
1546bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) {
1547  unsigned NumArgs = TheCall->getNumArgs();
1548
1549  if (NumArgs > 3)
1550    return Diag(TheCall->getLocEnd(),
1551             diag::err_typecheck_call_too_many_args_at_most)
1552             << 0 /*function call*/ << 3 << NumArgs
1553             << TheCall->getSourceRange();
1554
1555  // Argument 0 is checked for us and the remaining arguments must be
1556  // constant integers.
1557  for (unsigned i = 1; i != NumArgs; ++i) {
1558    Expr *Arg = TheCall->getArg(i);
1559
1560    // We can't check the value of a dependent argument.
1561    if (Arg->isTypeDependent() || Arg->isValueDependent())
1562      continue;
1563
1564    llvm::APSInt Result;
1565    if (SemaBuiltinConstantArg(TheCall, i, Result))
1566      return true;
1567
1568    // FIXME: gcc issues a warning and rewrites these to 0. These
1569    // seems especially odd for the third argument since the default
1570    // is 3.
1571    if (i == 1) {
1572      if (Result.getLimitedValue() > 1)
1573        return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
1574             << "0" << "1" << Arg->getSourceRange();
1575    } else {
1576      if (Result.getLimitedValue() > 3)
1577        return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
1578            << "0" << "3" << Arg->getSourceRange();
1579    }
1580  }
1581
1582  return false;
1583}
1584
1585/// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr
1586/// TheCall is a constant expression.
1587bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum,
1588                                  llvm::APSInt &Result) {
1589  Expr *Arg = TheCall->getArg(ArgNum);
1590  DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
1591  FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
1592
1593  if (Arg->isTypeDependent() || Arg->isValueDependent()) return false;
1594
1595  if (!Arg->isIntegerConstantExpr(Result, Context))
1596    return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type)
1597                << FDecl->getDeclName() <<  Arg->getSourceRange();
1598
1599  return false;
1600}
1601
1602/// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr,
1603/// int type). This simply type checks that type is one of the defined
1604/// constants (0-3).
1605// For compatibility check 0-3, llvm only handles 0 and 2.
1606bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) {
1607  llvm::APSInt Result;
1608
1609  // We can't check the value of a dependent argument.
1610  if (TheCall->getArg(1)->isTypeDependent() ||
1611      TheCall->getArg(1)->isValueDependent())
1612    return false;
1613
1614  // Check constant-ness first.
1615  if (SemaBuiltinConstantArg(TheCall, 1, Result))
1616    return true;
1617
1618  Expr *Arg = TheCall->getArg(1);
1619  if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) {
1620    return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
1621             << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
1622  }
1623
1624  return false;
1625}
1626
1627/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val).
1628/// This checks that val is a constant 1.
1629bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) {
1630  Expr *Arg = TheCall->getArg(1);
1631  llvm::APSInt Result;
1632
1633  // TODO: This is less than ideal. Overload this to take a value.
1634  if (SemaBuiltinConstantArg(TheCall, 1, Result))
1635    return true;
1636
1637  if (Result != 1)
1638    return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val)
1639             << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
1640
1641  return false;
1642}
1643
1644// Determine if an expression is a string literal or constant string.
1645// If this function returns false on the arguments to a function expecting a
1646// format string, we will usually need to emit a warning.
1647// True string literals are then checked by CheckFormatString.
1648Sema::StringLiteralCheckType
1649Sema::checkFormatStringExpr(const Expr *E, Expr **Args,
1650                            unsigned NumArgs, bool HasVAListArg,
1651                            unsigned format_idx, unsigned firstDataArg,
1652                            FormatStringType Type, VariadicCallType CallType,
1653                            bool inFunctionCall) {
1654 tryAgain:
1655  if (E->isTypeDependent() || E->isValueDependent())
1656    return SLCT_NotALiteral;
1657
1658  E = E->IgnoreParenCasts();
1659
1660  if (E->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull))
1661    // Technically -Wformat-nonliteral does not warn about this case.
1662    // The behavior of printf and friends in this case is implementation
1663    // dependent.  Ideally if the format string cannot be null then
1664    // it should have a 'nonnull' attribute in the function prototype.
1665    return SLCT_CheckedLiteral;
1666
1667  switch (E->getStmtClass()) {
1668  case Stmt::BinaryConditionalOperatorClass:
1669  case Stmt::ConditionalOperatorClass: {
1670    // The expression is a literal if both sub-expressions were, and it was
1671    // completely checked only if both sub-expressions were checked.
1672    const AbstractConditionalOperator *C =
1673        cast<AbstractConditionalOperator>(E);
1674    StringLiteralCheckType Left =
1675        checkFormatStringExpr(C->getTrueExpr(), Args, NumArgs,
1676                              HasVAListArg, format_idx, firstDataArg,
1677                              Type, CallType, inFunctionCall);
1678    if (Left == SLCT_NotALiteral)
1679      return SLCT_NotALiteral;
1680    StringLiteralCheckType Right =
1681        checkFormatStringExpr(C->getFalseExpr(), Args, NumArgs,
1682                              HasVAListArg, format_idx, firstDataArg,
1683                              Type, CallType, inFunctionCall);
1684    return Left < Right ? Left : Right;
1685  }
1686
1687  case Stmt::ImplicitCastExprClass: {
1688    E = cast<ImplicitCastExpr>(E)->getSubExpr();
1689    goto tryAgain;
1690  }
1691
1692  case Stmt::OpaqueValueExprClass:
1693    if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) {
1694      E = src;
1695      goto tryAgain;
1696    }
1697    return SLCT_NotALiteral;
1698
1699  case Stmt::PredefinedExprClass:
1700    // While __func__, etc., are technically not string literals, they
1701    // cannot contain format specifiers and thus are not a security
1702    // liability.
1703    return SLCT_UncheckedLiteral;
1704
1705  case Stmt::DeclRefExprClass: {
1706    const DeclRefExpr *DR = cast<DeclRefExpr>(E);
1707
1708    // As an exception, do not flag errors for variables binding to
1709    // const string literals.
1710    if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
1711      bool isConstant = false;
1712      QualType T = DR->getType();
1713
1714      if (const ArrayType *AT = Context.getAsArrayType(T)) {
1715        isConstant = AT->getElementType().isConstant(Context);
1716      } else if (const PointerType *PT = T->getAs<PointerType>()) {
1717        isConstant = T.isConstant(Context) &&
1718                     PT->getPointeeType().isConstant(Context);
1719      } else if (T->isObjCObjectPointerType()) {
1720        // In ObjC, there is usually no "const ObjectPointer" type,
1721        // so don't check if the pointee type is constant.
1722        isConstant = T.isConstant(Context);
1723      }
1724
1725      if (isConstant) {
1726        if (const Expr *Init = VD->getAnyInitializer()) {
1727          // Look through initializers like const char c[] = { "foo" }
1728          if (const InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) {
1729            if (InitList->isStringLiteralInit())
1730              Init = InitList->getInit(0)->IgnoreParenImpCasts();
1731          }
1732          return checkFormatStringExpr(Init, Args, NumArgs,
1733                                       HasVAListArg, format_idx,
1734                                       firstDataArg, Type, CallType,
1735                                       /*inFunctionCall*/false);
1736        }
1737      }
1738
1739      // For vprintf* functions (i.e., HasVAListArg==true), we add a
1740      // special check to see if the format string is a function parameter
1741      // of the function calling the printf function.  If the function
1742      // has an attribute indicating it is a printf-like function, then we
1743      // should suppress warnings concerning non-literals being used in a call
1744      // to a vprintf function.  For example:
1745      //
1746      // void
1747      // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){
1748      //      va_list ap;
1749      //      va_start(ap, fmt);
1750      //      vprintf(fmt, ap);  // Do NOT emit a warning about "fmt".
1751      //      ...
1752      //
1753      if (HasVAListArg) {
1754        if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(VD)) {
1755          if (const NamedDecl *ND = dyn_cast<NamedDecl>(PV->getDeclContext())) {
1756            int PVIndex = PV->getFunctionScopeIndex() + 1;
1757            for (specific_attr_iterator<FormatAttr>
1758                 i = ND->specific_attr_begin<FormatAttr>(),
1759                 e = ND->specific_attr_end<FormatAttr>(); i != e ; ++i) {
1760              FormatAttr *PVFormat = *i;
1761              // adjust for implicit parameter
1762              if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
1763                if (MD->isInstance())
1764                  ++PVIndex;
1765              // We also check if the formats are compatible.
1766              // We can't pass a 'scanf' string to a 'printf' function.
1767              if (PVIndex == PVFormat->getFormatIdx() &&
1768                  Type == GetFormatStringType(PVFormat))
1769                return SLCT_UncheckedLiteral;
1770            }
1771          }
1772        }
1773      }
1774    }
1775
1776    return SLCT_NotALiteral;
1777  }
1778
1779  case Stmt::CallExprClass:
1780  case Stmt::CXXMemberCallExprClass: {
1781    const CallExpr *CE = cast<CallExpr>(E);
1782    if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) {
1783      if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) {
1784        unsigned ArgIndex = FA->getFormatIdx();
1785        if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
1786          if (MD->isInstance())
1787            --ArgIndex;
1788        const Expr *Arg = CE->getArg(ArgIndex - 1);
1789
1790        return checkFormatStringExpr(Arg, Args, NumArgs,
1791                                     HasVAListArg, format_idx, firstDataArg,
1792                                     Type, CallType, inFunctionCall);
1793      } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
1794        unsigned BuiltinID = FD->getBuiltinID();
1795        if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString ||
1796            BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) {
1797          const Expr *Arg = CE->getArg(0);
1798          return checkFormatStringExpr(Arg, Args, NumArgs,
1799                                       HasVAListArg, format_idx,
1800                                       firstDataArg, Type, CallType,
1801                                       inFunctionCall);
1802        }
1803      }
1804    }
1805
1806    return SLCT_NotALiteral;
1807  }
1808  case Stmt::ObjCStringLiteralClass:
1809  case Stmt::StringLiteralClass: {
1810    const StringLiteral *StrE = NULL;
1811
1812    if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E))
1813      StrE = ObjCFExpr->getString();
1814    else
1815      StrE = cast<StringLiteral>(E);
1816
1817    if (StrE) {
1818      CheckFormatString(StrE, E, Args, NumArgs, HasVAListArg, format_idx,
1819                        firstDataArg, Type, inFunctionCall, CallType);
1820      return SLCT_CheckedLiteral;
1821    }
1822
1823    return SLCT_NotALiteral;
1824  }
1825
1826  default:
1827    return SLCT_NotALiteral;
1828  }
1829}
1830
1831void
1832Sema::CheckNonNullArguments(const NonNullAttr *NonNull,
1833                            const Expr * const *ExprArgs,
1834                            SourceLocation CallSiteLoc) {
1835  for (NonNullAttr::args_iterator i = NonNull->args_begin(),
1836                                  e = NonNull->args_end();
1837       i != e; ++i) {
1838    const Expr *ArgExpr = ExprArgs[*i];
1839    if (ArgExpr->isNullPointerConstant(Context,
1840                                       Expr::NPC_ValueDependentIsNotNull))
1841      Diag(CallSiteLoc, diag::warn_null_arg) << ArgExpr->getSourceRange();
1842  }
1843}
1844
1845Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) {
1846  return llvm::StringSwitch<FormatStringType>(Format->getType())
1847  .Case("scanf", FST_Scanf)
1848  .Cases("printf", "printf0", FST_Printf)
1849  .Cases("NSString", "CFString", FST_NSString)
1850  .Case("strftime", FST_Strftime)
1851  .Case("strfmon", FST_Strfmon)
1852  .Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf)
1853  .Default(FST_Unknown);
1854}
1855
1856/// CheckFormatArguments - Check calls to printf and scanf (and similar
1857/// functions) for correct use of format strings.
1858/// Returns true if a format string has been fully checked.
1859bool Sema::CheckFormatArguments(const FormatAttr *Format, Expr **Args,
1860                                unsigned NumArgs, bool IsCXXMember,
1861                                VariadicCallType CallType,
1862                                SourceLocation Loc, SourceRange Range) {
1863  FormatStringInfo FSI;
1864  if (getFormatStringInfo(Format, IsCXXMember, &FSI))
1865    return CheckFormatArguments(Args, NumArgs, FSI.HasVAListArg, FSI.FormatIdx,
1866                                FSI.FirstDataArg, GetFormatStringType(Format),
1867                                CallType, Loc, Range);
1868  return false;
1869}
1870
1871bool Sema::CheckFormatArguments(Expr **Args, unsigned NumArgs,
1872                                bool HasVAListArg, unsigned format_idx,
1873                                unsigned firstDataArg, FormatStringType Type,
1874                                VariadicCallType CallType,
1875                                SourceLocation Loc, SourceRange Range) {
1876  // CHECK: printf/scanf-like function is called with no format string.
1877  if (format_idx >= NumArgs) {
1878    Diag(Loc, diag::warn_missing_format_string) << Range;
1879    return false;
1880  }
1881
1882  const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts();
1883
1884  // CHECK: format string is not a string literal.
1885  //
1886  // Dynamically generated format strings are difficult to
1887  // automatically vet at compile time.  Requiring that format strings
1888  // are string literals: (1) permits the checking of format strings by
1889  // the compiler and thereby (2) can practically remove the source of
1890  // many format string exploits.
1891
1892  // Format string can be either ObjC string (e.g. @"%d") or
1893  // C string (e.g. "%d")
1894  // ObjC string uses the same format specifiers as C string, so we can use
1895  // the same format string checking logic for both ObjC and C strings.
1896  StringLiteralCheckType CT =
1897      checkFormatStringExpr(OrigFormatExpr, Args, NumArgs, HasVAListArg,
1898                            format_idx, firstDataArg, Type, CallType);
1899  if (CT != SLCT_NotALiteral)
1900    // Literal format string found, check done!
1901    return CT == SLCT_CheckedLiteral;
1902
1903  // Strftime is particular as it always uses a single 'time' argument,
1904  // so it is safe to pass a non-literal string.
1905  if (Type == FST_Strftime)
1906    return false;
1907
1908  // Do not emit diag when the string param is a macro expansion and the
1909  // format is either NSString or CFString. This is a hack to prevent
1910  // diag when using the NSLocalizedString and CFCopyLocalizedString macros
1911  // which are usually used in place of NS and CF string literals.
1912  if (Type == FST_NSString &&
1913      SourceMgr.isInSystemMacro(Args[format_idx]->getLocStart()))
1914    return false;
1915
1916  // If there are no arguments specified, warn with -Wformat-security, otherwise
1917  // warn only with -Wformat-nonliteral.
1918  if (NumArgs == format_idx+1)
1919    Diag(Args[format_idx]->getLocStart(),
1920         diag::warn_format_nonliteral_noargs)
1921      << OrigFormatExpr->getSourceRange();
1922  else
1923    Diag(Args[format_idx]->getLocStart(),
1924         diag::warn_format_nonliteral)
1925           << OrigFormatExpr->getSourceRange();
1926  return false;
1927}
1928
1929namespace {
1930class CheckFormatHandler : public analyze_format_string::FormatStringHandler {
1931protected:
1932  Sema &S;
1933  const StringLiteral *FExpr;
1934  const Expr *OrigFormatExpr;
1935  const unsigned FirstDataArg;
1936  const unsigned NumDataArgs;
1937  const char *Beg; // Start of format string.
1938  const bool HasVAListArg;
1939  const Expr * const *Args;
1940  const unsigned NumArgs;
1941  unsigned FormatIdx;
1942  llvm::BitVector CoveredArgs;
1943  bool usesPositionalArgs;
1944  bool atFirstArg;
1945  bool inFunctionCall;
1946  Sema::VariadicCallType CallType;
1947public:
1948  CheckFormatHandler(Sema &s, const StringLiteral *fexpr,
1949                     const Expr *origFormatExpr, unsigned firstDataArg,
1950                     unsigned numDataArgs, const char *beg, bool hasVAListArg,
1951                     Expr **args, unsigned numArgs,
1952                     unsigned formatIdx, bool inFunctionCall,
1953                     Sema::VariadicCallType callType)
1954    : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr),
1955      FirstDataArg(firstDataArg), NumDataArgs(numDataArgs),
1956      Beg(beg), HasVAListArg(hasVAListArg),
1957      Args(args), NumArgs(numArgs), FormatIdx(formatIdx),
1958      usesPositionalArgs(false), atFirstArg(true),
1959      inFunctionCall(inFunctionCall), CallType(callType) {
1960        CoveredArgs.resize(numDataArgs);
1961        CoveredArgs.reset();
1962      }
1963
1964  void DoneProcessing();
1965
1966  void HandleIncompleteSpecifier(const char *startSpecifier,
1967                                 unsigned specifierLen);
1968
1969  void HandleInvalidLengthModifier(
1970      const analyze_format_string::FormatSpecifier &FS,
1971      const analyze_format_string::ConversionSpecifier &CS,
1972      const char *startSpecifier, unsigned specifierLen, unsigned DiagID);
1973
1974  void HandleNonStandardLengthModifier(
1975      const analyze_format_string::FormatSpecifier &FS,
1976      const char *startSpecifier, unsigned specifierLen);
1977
1978  void HandleNonStandardConversionSpecifier(
1979      const analyze_format_string::ConversionSpecifier &CS,
1980      const char *startSpecifier, unsigned specifierLen);
1981
1982  virtual void HandlePosition(const char *startPos, unsigned posLen);
1983
1984  virtual void HandleInvalidPosition(const char *startSpecifier,
1985                                     unsigned specifierLen,
1986                                     analyze_format_string::PositionContext p);
1987
1988  virtual void HandleZeroPosition(const char *startPos, unsigned posLen);
1989
1990  void HandleNullChar(const char *nullCharacter);
1991
1992  template <typename Range>
1993  static void EmitFormatDiagnostic(Sema &S, bool inFunctionCall,
1994                                   const Expr *ArgumentExpr,
1995                                   PartialDiagnostic PDiag,
1996                                   SourceLocation StringLoc,
1997                                   bool IsStringLocation, Range StringRange,
1998                            ArrayRef<FixItHint> Fixit = ArrayRef<FixItHint>());
1999
2000protected:
2001  bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc,
2002                                        const char *startSpec,
2003                                        unsigned specifierLen,
2004                                        const char *csStart, unsigned csLen);
2005
2006  void HandlePositionalNonpositionalArgs(SourceLocation Loc,
2007                                         const char *startSpec,
2008                                         unsigned specifierLen);
2009
2010  SourceRange getFormatStringRange();
2011  CharSourceRange getSpecifierRange(const char *startSpecifier,
2012                                    unsigned specifierLen);
2013  SourceLocation getLocationOfByte(const char *x);
2014
2015  const Expr *getDataArg(unsigned i) const;
2016
2017  bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS,
2018                    const analyze_format_string::ConversionSpecifier &CS,
2019                    const char *startSpecifier, unsigned specifierLen,
2020                    unsigned argIndex);
2021
2022  template <typename Range>
2023  void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc,
2024                            bool IsStringLocation, Range StringRange,
2025                            ArrayRef<FixItHint> Fixit = ArrayRef<FixItHint>());
2026
2027  void CheckPositionalAndNonpositionalArgs(
2028      const analyze_format_string::FormatSpecifier *FS);
2029};
2030}
2031
2032SourceRange CheckFormatHandler::getFormatStringRange() {
2033  return OrigFormatExpr->getSourceRange();
2034}
2035
2036CharSourceRange CheckFormatHandler::
2037getSpecifierRange(const char *startSpecifier, unsigned specifierLen) {
2038  SourceLocation Start = getLocationOfByte(startSpecifier);
2039  SourceLocation End   = getLocationOfByte(startSpecifier + specifierLen - 1);
2040
2041  // Advance the end SourceLocation by one due to half-open ranges.
2042  End = End.getLocWithOffset(1);
2043
2044  return CharSourceRange::getCharRange(Start, End);
2045}
2046
2047SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) {
2048  return S.getLocationOfStringLiteralByte(FExpr, x - Beg);
2049}
2050
2051void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier,
2052                                                   unsigned specifierLen){
2053  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier),
2054                       getLocationOfByte(startSpecifier),
2055                       /*IsStringLocation*/true,
2056                       getSpecifierRange(startSpecifier, specifierLen));
2057}
2058
2059void CheckFormatHandler::HandleInvalidLengthModifier(
2060    const analyze_format_string::FormatSpecifier &FS,
2061    const analyze_format_string::ConversionSpecifier &CS,
2062    const char *startSpecifier, unsigned specifierLen, unsigned DiagID) {
2063  using namespace analyze_format_string;
2064
2065  const LengthModifier &LM = FS.getLengthModifier();
2066  CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength());
2067
2068  // See if we know how to fix this length modifier.
2069  llvm::Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier();
2070  if (FixedLM) {
2071    EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(),
2072                         getLocationOfByte(LM.getStart()),
2073                         /*IsStringLocation*/true,
2074                         getSpecifierRange(startSpecifier, specifierLen));
2075
2076    S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier)
2077      << FixedLM->toString()
2078      << FixItHint::CreateReplacement(LMRange, FixedLM->toString());
2079
2080  } else {
2081    FixItHint Hint;
2082    if (DiagID == diag::warn_format_nonsensical_length)
2083      Hint = FixItHint::CreateRemoval(LMRange);
2084
2085    EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(),
2086                         getLocationOfByte(LM.getStart()),
2087                         /*IsStringLocation*/true,
2088                         getSpecifierRange(startSpecifier, specifierLen),
2089                         Hint);
2090  }
2091}
2092
2093void CheckFormatHandler::HandleNonStandardLengthModifier(
2094    const analyze_format_string::FormatSpecifier &FS,
2095    const char *startSpecifier, unsigned specifierLen) {
2096  using namespace analyze_format_string;
2097
2098  const LengthModifier &LM = FS.getLengthModifier();
2099  CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength());
2100
2101  // See if we know how to fix this length modifier.
2102  llvm::Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier();
2103  if (FixedLM) {
2104    EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
2105                           << LM.toString() << 0,
2106                         getLocationOfByte(LM.getStart()),
2107                         /*IsStringLocation*/true,
2108                         getSpecifierRange(startSpecifier, specifierLen));
2109
2110    S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier)
2111      << FixedLM->toString()
2112      << FixItHint::CreateReplacement(LMRange, FixedLM->toString());
2113
2114  } else {
2115    EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
2116                           << LM.toString() << 0,
2117                         getLocationOfByte(LM.getStart()),
2118                         /*IsStringLocation*/true,
2119                         getSpecifierRange(startSpecifier, specifierLen));
2120  }
2121}
2122
2123void CheckFormatHandler::HandleNonStandardConversionSpecifier(
2124    const analyze_format_string::ConversionSpecifier &CS,
2125    const char *startSpecifier, unsigned specifierLen) {
2126  using namespace analyze_format_string;
2127
2128  // See if we know how to fix this conversion specifier.
2129  llvm::Optional<ConversionSpecifier> FixedCS = CS.getStandardSpecifier();
2130  if (FixedCS) {
2131    EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
2132                          << CS.toString() << /*conversion specifier*/1,
2133                         getLocationOfByte(CS.getStart()),
2134                         /*IsStringLocation*/true,
2135                         getSpecifierRange(startSpecifier, specifierLen));
2136
2137    CharSourceRange CSRange = getSpecifierRange(CS.getStart(), CS.getLength());
2138    S.Diag(getLocationOfByte(CS.getStart()), diag::note_format_fix_specifier)
2139      << FixedCS->toString()
2140      << FixItHint::CreateReplacement(CSRange, FixedCS->toString());
2141  } else {
2142    EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
2143                          << CS.toString() << /*conversion specifier*/1,
2144                         getLocationOfByte(CS.getStart()),
2145                         /*IsStringLocation*/true,
2146                         getSpecifierRange(startSpecifier, specifierLen));
2147  }
2148}
2149
2150void CheckFormatHandler::HandlePosition(const char *startPos,
2151                                        unsigned posLen) {
2152  EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg),
2153                               getLocationOfByte(startPos),
2154                               /*IsStringLocation*/true,
2155                               getSpecifierRange(startPos, posLen));
2156}
2157
2158void
2159CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen,
2160                                     analyze_format_string::PositionContext p) {
2161  EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier)
2162                         << (unsigned) p,
2163                       getLocationOfByte(startPos), /*IsStringLocation*/true,
2164                       getSpecifierRange(startPos, posLen));
2165}
2166
2167void CheckFormatHandler::HandleZeroPosition(const char *startPos,
2168                                            unsigned posLen) {
2169  EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier),
2170                               getLocationOfByte(startPos),
2171                               /*IsStringLocation*/true,
2172                               getSpecifierRange(startPos, posLen));
2173}
2174
2175void CheckFormatHandler::HandleNullChar(const char *nullCharacter) {
2176  if (!isa<ObjCStringLiteral>(OrigFormatExpr)) {
2177    // The presence of a null character is likely an error.
2178    EmitFormatDiagnostic(
2179      S.PDiag(diag::warn_printf_format_string_contains_null_char),
2180      getLocationOfByte(nullCharacter), /*IsStringLocation*/true,
2181      getFormatStringRange());
2182  }
2183}
2184
2185// Note that this may return NULL if there was an error parsing or building
2186// one of the argument expressions.
2187const Expr *CheckFormatHandler::getDataArg(unsigned i) const {
2188  return Args[FirstDataArg + i];
2189}
2190
2191void CheckFormatHandler::DoneProcessing() {
2192    // Does the number of data arguments exceed the number of
2193    // format conversions in the format string?
2194  if (!HasVAListArg) {
2195      // Find any arguments that weren't covered.
2196    CoveredArgs.flip();
2197    signed notCoveredArg = CoveredArgs.find_first();
2198    if (notCoveredArg >= 0) {
2199      assert((unsigned)notCoveredArg < NumDataArgs);
2200      if (const Expr *E = getDataArg((unsigned) notCoveredArg)) {
2201        SourceLocation Loc = E->getLocStart();
2202        if (!S.getSourceManager().isInSystemMacro(Loc)) {
2203          EmitFormatDiagnostic(S.PDiag(diag::warn_printf_data_arg_not_used),
2204                               Loc, /*IsStringLocation*/false,
2205                               getFormatStringRange());
2206        }
2207      }
2208    }
2209  }
2210}
2211
2212bool
2213CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex,
2214                                                     SourceLocation Loc,
2215                                                     const char *startSpec,
2216                                                     unsigned specifierLen,
2217                                                     const char *csStart,
2218                                                     unsigned csLen) {
2219
2220  bool keepGoing = true;
2221  if (argIndex < NumDataArgs) {
2222    // Consider the argument coverered, even though the specifier doesn't
2223    // make sense.
2224    CoveredArgs.set(argIndex);
2225  }
2226  else {
2227    // If argIndex exceeds the number of data arguments we
2228    // don't issue a warning because that is just a cascade of warnings (and
2229    // they may have intended '%%' anyway). We don't want to continue processing
2230    // the format string after this point, however, as we will like just get
2231    // gibberish when trying to match arguments.
2232    keepGoing = false;
2233  }
2234
2235  EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion)
2236                         << StringRef(csStart, csLen),
2237                       Loc, /*IsStringLocation*/true,
2238                       getSpecifierRange(startSpec, specifierLen));
2239
2240  return keepGoing;
2241}
2242
2243void
2244CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc,
2245                                                      const char *startSpec,
2246                                                      unsigned specifierLen) {
2247  EmitFormatDiagnostic(
2248    S.PDiag(diag::warn_format_mix_positional_nonpositional_args),
2249    Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen));
2250}
2251
2252bool
2253CheckFormatHandler::CheckNumArgs(
2254  const analyze_format_string::FormatSpecifier &FS,
2255  const analyze_format_string::ConversionSpecifier &CS,
2256  const char *startSpecifier, unsigned specifierLen, unsigned argIndex) {
2257
2258  if (argIndex >= NumDataArgs) {
2259    PartialDiagnostic PDiag = FS.usesPositionalArg()
2260      ? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args)
2261           << (argIndex+1) << NumDataArgs)
2262      : S.PDiag(diag::warn_printf_insufficient_data_args);
2263    EmitFormatDiagnostic(
2264      PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true,
2265      getSpecifierRange(startSpecifier, specifierLen));
2266    return false;
2267  }
2268  return true;
2269}
2270
2271template<typename Range>
2272void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag,
2273                                              SourceLocation Loc,
2274                                              bool IsStringLocation,
2275                                              Range StringRange,
2276                                              ArrayRef<FixItHint> FixIt) {
2277  EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag,
2278                       Loc, IsStringLocation, StringRange, FixIt);
2279}
2280
2281/// \brief If the format string is not within the funcion call, emit a note
2282/// so that the function call and string are in diagnostic messages.
2283///
2284/// \param InFunctionCall if true, the format string is within the function
2285/// call and only one diagnostic message will be produced.  Otherwise, an
2286/// extra note will be emitted pointing to location of the format string.
2287///
2288/// \param ArgumentExpr the expression that is passed as the format string
2289/// argument in the function call.  Used for getting locations when two
2290/// diagnostics are emitted.
2291///
2292/// \param PDiag the callee should already have provided any strings for the
2293/// diagnostic message.  This function only adds locations and fixits
2294/// to diagnostics.
2295///
2296/// \param Loc primary location for diagnostic.  If two diagnostics are
2297/// required, one will be at Loc and a new SourceLocation will be created for
2298/// the other one.
2299///
2300/// \param IsStringLocation if true, Loc points to the format string should be
2301/// used for the note.  Otherwise, Loc points to the argument list and will
2302/// be used with PDiag.
2303///
2304/// \param StringRange some or all of the string to highlight.  This is
2305/// templated so it can accept either a CharSourceRange or a SourceRange.
2306///
2307/// \param FixIt optional fix it hint for the format string.
2308template<typename Range>
2309void CheckFormatHandler::EmitFormatDiagnostic(Sema &S, bool InFunctionCall,
2310                                              const Expr *ArgumentExpr,
2311                                              PartialDiagnostic PDiag,
2312                                              SourceLocation Loc,
2313                                              bool IsStringLocation,
2314                                              Range StringRange,
2315                                              ArrayRef<FixItHint> FixIt) {
2316  if (InFunctionCall) {
2317    const Sema::SemaDiagnosticBuilder &D = S.Diag(Loc, PDiag);
2318    D << StringRange;
2319    for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end();
2320         I != E; ++I) {
2321      D << *I;
2322    }
2323  } else {
2324    S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag)
2325      << ArgumentExpr->getSourceRange();
2326
2327    const Sema::SemaDiagnosticBuilder &Note =
2328      S.Diag(IsStringLocation ? Loc : StringRange.getBegin(),
2329             diag::note_format_string_defined);
2330
2331    Note << StringRange;
2332    for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end();
2333         I != E; ++I) {
2334      Note << *I;
2335    }
2336  }
2337}
2338
2339//===--- CHECK: Printf format string checking ------------------------------===//
2340
2341namespace {
2342class CheckPrintfHandler : public CheckFormatHandler {
2343  bool ObjCContext;
2344public:
2345  CheckPrintfHandler(Sema &s, const StringLiteral *fexpr,
2346                     const Expr *origFormatExpr, unsigned firstDataArg,
2347                     unsigned numDataArgs, bool isObjC,
2348                     const char *beg, bool hasVAListArg,
2349                     Expr **Args, unsigned NumArgs,
2350                     unsigned formatIdx, bool inFunctionCall,
2351                     Sema::VariadicCallType CallType)
2352  : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
2353                       numDataArgs, beg, hasVAListArg, Args, NumArgs,
2354                       formatIdx, inFunctionCall, CallType), ObjCContext(isObjC)
2355  {}
2356
2357
2358  bool HandleInvalidPrintfConversionSpecifier(
2359                                      const analyze_printf::PrintfSpecifier &FS,
2360                                      const char *startSpecifier,
2361                                      unsigned specifierLen);
2362
2363  bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS,
2364                             const char *startSpecifier,
2365                             unsigned specifierLen);
2366  bool checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
2367                       const char *StartSpecifier,
2368                       unsigned SpecifierLen,
2369                       const Expr *E);
2370
2371  bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k,
2372                    const char *startSpecifier, unsigned specifierLen);
2373  void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS,
2374                           const analyze_printf::OptionalAmount &Amt,
2375                           unsigned type,
2376                           const char *startSpecifier, unsigned specifierLen);
2377  void HandleFlag(const analyze_printf::PrintfSpecifier &FS,
2378                  const analyze_printf::OptionalFlag &flag,
2379                  const char *startSpecifier, unsigned specifierLen);
2380  void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS,
2381                         const analyze_printf::OptionalFlag &ignoredFlag,
2382                         const analyze_printf::OptionalFlag &flag,
2383                         const char *startSpecifier, unsigned specifierLen);
2384  bool checkForCStrMembers(const analyze_printf::ArgType &AT,
2385                           const Expr *E, const CharSourceRange &CSR);
2386
2387};
2388}
2389
2390bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier(
2391                                      const analyze_printf::PrintfSpecifier &FS,
2392                                      const char *startSpecifier,
2393                                      unsigned specifierLen) {
2394  const analyze_printf::PrintfConversionSpecifier &CS =
2395    FS.getConversionSpecifier();
2396
2397  return HandleInvalidConversionSpecifier(FS.getArgIndex(),
2398                                          getLocationOfByte(CS.getStart()),
2399                                          startSpecifier, specifierLen,
2400                                          CS.getStart(), CS.getLength());
2401}
2402
2403bool CheckPrintfHandler::HandleAmount(
2404                               const analyze_format_string::OptionalAmount &Amt,
2405                               unsigned k, const char *startSpecifier,
2406                               unsigned specifierLen) {
2407
2408  if (Amt.hasDataArgument()) {
2409    if (!HasVAListArg) {
2410      unsigned argIndex = Amt.getArgIndex();
2411      if (argIndex >= NumDataArgs) {
2412        EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg)
2413                               << k,
2414                             getLocationOfByte(Amt.getStart()),
2415                             /*IsStringLocation*/true,
2416                             getSpecifierRange(startSpecifier, specifierLen));
2417        // Don't do any more checking.  We will just emit
2418        // spurious errors.
2419        return false;
2420      }
2421
2422      // Type check the data argument.  It should be an 'int'.
2423      // Although not in conformance with C99, we also allow the argument to be
2424      // an 'unsigned int' as that is a reasonably safe case.  GCC also
2425      // doesn't emit a warning for that case.
2426      CoveredArgs.set(argIndex);
2427      const Expr *Arg = getDataArg(argIndex);
2428      if (!Arg)
2429        return false;
2430
2431      QualType T = Arg->getType();
2432
2433      const analyze_printf::ArgType &AT = Amt.getArgType(S.Context);
2434      assert(AT.isValid());
2435
2436      if (!AT.matchesType(S.Context, T)) {
2437        EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type)
2438                               << k << AT.getRepresentativeTypeName(S.Context)
2439                               << T << Arg->getSourceRange(),
2440                             getLocationOfByte(Amt.getStart()),
2441                             /*IsStringLocation*/true,
2442                             getSpecifierRange(startSpecifier, specifierLen));
2443        // Don't do any more checking.  We will just emit
2444        // spurious errors.
2445        return false;
2446      }
2447    }
2448  }
2449  return true;
2450}
2451
2452void CheckPrintfHandler::HandleInvalidAmount(
2453                                      const analyze_printf::PrintfSpecifier &FS,
2454                                      const analyze_printf::OptionalAmount &Amt,
2455                                      unsigned type,
2456                                      const char *startSpecifier,
2457                                      unsigned specifierLen) {
2458  const analyze_printf::PrintfConversionSpecifier &CS =
2459    FS.getConversionSpecifier();
2460
2461  FixItHint fixit =
2462    Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant
2463      ? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(),
2464                                 Amt.getConstantLength()))
2465      : FixItHint();
2466
2467  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount)
2468                         << type << CS.toString(),
2469                       getLocationOfByte(Amt.getStart()),
2470                       /*IsStringLocation*/true,
2471                       getSpecifierRange(startSpecifier, specifierLen),
2472                       fixit);
2473}
2474
2475void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS,
2476                                    const analyze_printf::OptionalFlag &flag,
2477                                    const char *startSpecifier,
2478                                    unsigned specifierLen) {
2479  // Warn about pointless flag with a fixit removal.
2480  const analyze_printf::PrintfConversionSpecifier &CS =
2481    FS.getConversionSpecifier();
2482  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag)
2483                         << flag.toString() << CS.toString(),
2484                       getLocationOfByte(flag.getPosition()),
2485                       /*IsStringLocation*/true,
2486                       getSpecifierRange(startSpecifier, specifierLen),
2487                       FixItHint::CreateRemoval(
2488                         getSpecifierRange(flag.getPosition(), 1)));
2489}
2490
2491void CheckPrintfHandler::HandleIgnoredFlag(
2492                                const analyze_printf::PrintfSpecifier &FS,
2493                                const analyze_printf::OptionalFlag &ignoredFlag,
2494                                const analyze_printf::OptionalFlag &flag,
2495                                const char *startSpecifier,
2496                                unsigned specifierLen) {
2497  // Warn about ignored flag with a fixit removal.
2498  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag)
2499                         << ignoredFlag.toString() << flag.toString(),
2500                       getLocationOfByte(ignoredFlag.getPosition()),
2501                       /*IsStringLocation*/true,
2502                       getSpecifierRange(startSpecifier, specifierLen),
2503                       FixItHint::CreateRemoval(
2504                         getSpecifierRange(ignoredFlag.getPosition(), 1)));
2505}
2506
2507// Determines if the specified is a C++ class or struct containing
2508// a member with the specified name and kind (e.g. a CXXMethodDecl named
2509// "c_str()").
2510template<typename MemberKind>
2511static llvm::SmallPtrSet<MemberKind*, 1>
2512CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) {
2513  const RecordType *RT = Ty->getAs<RecordType>();
2514  llvm::SmallPtrSet<MemberKind*, 1> Results;
2515
2516  if (!RT)
2517    return Results;
2518  const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl());
2519  if (!RD)
2520    return Results;
2521
2522  LookupResult R(S, &S.PP.getIdentifierTable().get(Name), SourceLocation(),
2523                 Sema::LookupMemberName);
2524
2525  // We just need to include all members of the right kind turned up by the
2526  // filter, at this point.
2527  if (S.LookupQualifiedName(R, RT->getDecl()))
2528    for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) {
2529      NamedDecl *decl = (*I)->getUnderlyingDecl();
2530      if (MemberKind *FK = dyn_cast<MemberKind>(decl))
2531        Results.insert(FK);
2532    }
2533  return Results;
2534}
2535
2536// Check if a (w)string was passed when a (w)char* was needed, and offer a
2537// better diagnostic if so. AT is assumed to be valid.
2538// Returns true when a c_str() conversion method is found.
2539bool CheckPrintfHandler::checkForCStrMembers(
2540    const analyze_printf::ArgType &AT, const Expr *E,
2541    const CharSourceRange &CSR) {
2542  typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet;
2543
2544  MethodSet Results =
2545      CXXRecordMembersNamed<CXXMethodDecl>("c_str", S, E->getType());
2546
2547  for (MethodSet::iterator MI = Results.begin(), ME = Results.end();
2548       MI != ME; ++MI) {
2549    const CXXMethodDecl *Method = *MI;
2550    if (Method->getNumParams() == 0 &&
2551          AT.matchesType(S.Context, Method->getResultType())) {
2552      // FIXME: Suggest parens if the expression needs them.
2553      SourceLocation EndLoc =
2554          S.getPreprocessor().getLocForEndOfToken(E->getLocEnd());
2555      S.Diag(E->getLocStart(), diag::note_printf_c_str)
2556          << "c_str()"
2557          << FixItHint::CreateInsertion(EndLoc, ".c_str()");
2558      return true;
2559    }
2560  }
2561
2562  return false;
2563}
2564
2565bool
2566CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier
2567                                            &FS,
2568                                          const char *startSpecifier,
2569                                          unsigned specifierLen) {
2570
2571  using namespace analyze_format_string;
2572  using namespace analyze_printf;
2573  const PrintfConversionSpecifier &CS = FS.getConversionSpecifier();
2574
2575  if (FS.consumesDataArgument()) {
2576    if (atFirstArg) {
2577        atFirstArg = false;
2578        usesPositionalArgs = FS.usesPositionalArg();
2579    }
2580    else if (usesPositionalArgs != FS.usesPositionalArg()) {
2581      HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()),
2582                                        startSpecifier, specifierLen);
2583      return false;
2584    }
2585  }
2586
2587  // First check if the field width, precision, and conversion specifier
2588  // have matching data arguments.
2589  if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0,
2590                    startSpecifier, specifierLen)) {
2591    return false;
2592  }
2593
2594  if (!HandleAmount(FS.getPrecision(), /* precision */ 1,
2595                    startSpecifier, specifierLen)) {
2596    return false;
2597  }
2598
2599  if (!CS.consumesDataArgument()) {
2600    // FIXME: Technically specifying a precision or field width here
2601    // makes no sense.  Worth issuing a warning at some point.
2602    return true;
2603  }
2604
2605  // Consume the argument.
2606  unsigned argIndex = FS.getArgIndex();
2607  if (argIndex < NumDataArgs) {
2608    // The check to see if the argIndex is valid will come later.
2609    // We set the bit here because we may exit early from this
2610    // function if we encounter some other error.
2611    CoveredArgs.set(argIndex);
2612  }
2613
2614  // Check for using an Objective-C specific conversion specifier
2615  // in a non-ObjC literal.
2616  if (!ObjCContext && CS.isObjCArg()) {
2617    return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier,
2618                                                  specifierLen);
2619  }
2620
2621  // Check for invalid use of field width
2622  if (!FS.hasValidFieldWidth()) {
2623    HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0,
2624        startSpecifier, specifierLen);
2625  }
2626
2627  // Check for invalid use of precision
2628  if (!FS.hasValidPrecision()) {
2629    HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1,
2630        startSpecifier, specifierLen);
2631  }
2632
2633  // Check each flag does not conflict with any other component.
2634  if (!FS.hasValidThousandsGroupingPrefix())
2635    HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen);
2636  if (!FS.hasValidLeadingZeros())
2637    HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen);
2638  if (!FS.hasValidPlusPrefix())
2639    HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen);
2640  if (!FS.hasValidSpacePrefix())
2641    HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen);
2642  if (!FS.hasValidAlternativeForm())
2643    HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen);
2644  if (!FS.hasValidLeftJustified())
2645    HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen);
2646
2647  // Check that flags are not ignored by another flag
2648  if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+'
2649    HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(),
2650        startSpecifier, specifierLen);
2651  if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-'
2652    HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(),
2653            startSpecifier, specifierLen);
2654
2655  // Check the length modifier is valid with the given conversion specifier.
2656  if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo()))
2657    HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
2658                                diag::warn_format_nonsensical_length);
2659  else if (!FS.hasStandardLengthModifier())
2660    HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen);
2661  else if (!FS.hasStandardLengthConversionCombination())
2662    HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
2663                                diag::warn_format_non_standard_conversion_spec);
2664
2665  if (!FS.hasStandardConversionSpecifier(S.getLangOpts()))
2666    HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen);
2667
2668  // The remaining checks depend on the data arguments.
2669  if (HasVAListArg)
2670    return true;
2671
2672  if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
2673    return false;
2674
2675  const Expr *Arg = getDataArg(argIndex);
2676  if (!Arg)
2677    return true;
2678
2679  return checkFormatExpr(FS, startSpecifier, specifierLen, Arg);
2680}
2681
2682static bool requiresParensToAddCast(const Expr *E) {
2683  // FIXME: We should have a general way to reason about operator
2684  // precedence and whether parens are actually needed here.
2685  // Take care of a few common cases where they aren't.
2686  const Expr *Inside = E->IgnoreImpCasts();
2687  if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Inside))
2688    Inside = POE->getSyntacticForm()->IgnoreImpCasts();
2689
2690  switch (Inside->getStmtClass()) {
2691  case Stmt::ArraySubscriptExprClass:
2692  case Stmt::CallExprClass:
2693  case Stmt::CharacterLiteralClass:
2694  case Stmt::CXXBoolLiteralExprClass:
2695  case Stmt::DeclRefExprClass:
2696  case Stmt::FloatingLiteralClass:
2697  case Stmt::IntegerLiteralClass:
2698  case Stmt::MemberExprClass:
2699  case Stmt::ObjCArrayLiteralClass:
2700  case Stmt::ObjCBoolLiteralExprClass:
2701  case Stmt::ObjCBoxedExprClass:
2702  case Stmt::ObjCDictionaryLiteralClass:
2703  case Stmt::ObjCEncodeExprClass:
2704  case Stmt::ObjCIvarRefExprClass:
2705  case Stmt::ObjCMessageExprClass:
2706  case Stmt::ObjCPropertyRefExprClass:
2707  case Stmt::ObjCStringLiteralClass:
2708  case Stmt::ObjCSubscriptRefExprClass:
2709  case Stmt::ParenExprClass:
2710  case Stmt::StringLiteralClass:
2711  case Stmt::UnaryOperatorClass:
2712    return false;
2713  default:
2714    return true;
2715  }
2716}
2717
2718bool
2719CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
2720                                    const char *StartSpecifier,
2721                                    unsigned SpecifierLen,
2722                                    const Expr *E) {
2723  using namespace analyze_format_string;
2724  using namespace analyze_printf;
2725  // Now type check the data expression that matches the
2726  // format specifier.
2727  const analyze_printf::ArgType &AT = FS.getArgType(S.Context,
2728                                                    ObjCContext);
2729  if (!AT.isValid())
2730    return true;
2731
2732  QualType ExprTy = E->getType();
2733  if (AT.matchesType(S.Context, ExprTy))
2734    return true;
2735
2736  // Look through argument promotions for our error message's reported type.
2737  // This includes the integral and floating promotions, but excludes array
2738  // and function pointer decay; seeing that an argument intended to be a
2739  // string has type 'char [6]' is probably more confusing than 'char *'.
2740  if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
2741    if (ICE->getCastKind() == CK_IntegralCast ||
2742        ICE->getCastKind() == CK_FloatingCast) {
2743      E = ICE->getSubExpr();
2744      ExprTy = E->getType();
2745
2746      // Check if we didn't match because of an implicit cast from a 'char'
2747      // or 'short' to an 'int'.  This is done because printf is a varargs
2748      // function.
2749      if (ICE->getType() == S.Context.IntTy ||
2750          ICE->getType() == S.Context.UnsignedIntTy) {
2751        // All further checking is done on the subexpression.
2752        if (AT.matchesType(S.Context, ExprTy))
2753          return true;
2754      }
2755    }
2756  } else if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E)) {
2757    // Special case for 'a', which has type 'int' in C.
2758    // Note, however, that we do /not/ want to treat multibyte constants like
2759    // 'MooV' as characters! This form is deprecated but still exists.
2760    if (ExprTy == S.Context.IntTy)
2761      if (llvm::isUIntN(S.Context.getCharWidth(), CL->getValue()))
2762        ExprTy = S.Context.CharTy;
2763  }
2764
2765  // %C in an Objective-C context prints a unichar, not a wchar_t.
2766  // If the argument is an integer of some kind, believe the %C and suggest
2767  // a cast instead of changing the conversion specifier.
2768  QualType IntendedTy = ExprTy;
2769  if (ObjCContext &&
2770      FS.getConversionSpecifier().getKind() == ConversionSpecifier::CArg) {
2771    if (ExprTy->isIntegralOrUnscopedEnumerationType() &&
2772        !ExprTy->isCharType()) {
2773      // 'unichar' is defined as a typedef of unsigned short, but we should
2774      // prefer using the typedef if it is visible.
2775      IntendedTy = S.Context.UnsignedShortTy;
2776
2777      LookupResult Result(S, &S.Context.Idents.get("unichar"), E->getLocStart(),
2778                          Sema::LookupOrdinaryName);
2779      if (S.LookupName(Result, S.getCurScope())) {
2780        NamedDecl *ND = Result.getFoundDecl();
2781        if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(ND))
2782          if (TD->getUnderlyingType() == IntendedTy)
2783            IntendedTy = S.Context.getTypedefType(TD);
2784      }
2785    }
2786  }
2787
2788  // Special-case some of Darwin's platform-independence types by suggesting
2789  // casts to primitive types that are known to be large enough.
2790  bool ShouldNotPrintDirectly = false;
2791  if (S.Context.getTargetInfo().getTriple().isOSDarwin()) {
2792    if (const TypedefType *UserTy = IntendedTy->getAs<TypedefType>()) {
2793      StringRef Name = UserTy->getDecl()->getName();
2794      QualType CastTy = llvm::StringSwitch<QualType>(Name)
2795        .Case("NSInteger", S.Context.LongTy)
2796        .Case("NSUInteger", S.Context.UnsignedLongTy)
2797        .Case("SInt32", S.Context.IntTy)
2798        .Case("UInt32", S.Context.UnsignedIntTy)
2799        .Default(QualType());
2800
2801      if (!CastTy.isNull()) {
2802        ShouldNotPrintDirectly = true;
2803        IntendedTy = CastTy;
2804      }
2805    }
2806  }
2807
2808  // We may be able to offer a FixItHint if it is a supported type.
2809  PrintfSpecifier fixedFS = FS;
2810  bool success = fixedFS.fixType(IntendedTy, S.getLangOpts(),
2811                                 S.Context, ObjCContext);
2812
2813  if (success) {
2814    // Get the fix string from the fixed format specifier
2815    SmallString<16> buf;
2816    llvm::raw_svector_ostream os(buf);
2817    fixedFS.toString(os);
2818
2819    CharSourceRange SpecRange = getSpecifierRange(StartSpecifier, SpecifierLen);
2820
2821    if (IntendedTy == ExprTy) {
2822      // In this case, the specifier is wrong and should be changed to match
2823      // the argument.
2824      EmitFormatDiagnostic(
2825        S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
2826          << AT.getRepresentativeTypeName(S.Context) << IntendedTy
2827          << E->getSourceRange(),
2828        E->getLocStart(),
2829        /*IsStringLocation*/false,
2830        SpecRange,
2831        FixItHint::CreateReplacement(SpecRange, os.str()));
2832
2833    } else {
2834      // The canonical type for formatting this value is different from the
2835      // actual type of the expression. (This occurs, for example, with Darwin's
2836      // NSInteger on 32-bit platforms, where it is typedef'd as 'int', but
2837      // should be printed as 'long' for 64-bit compatibility.)
2838      // Rather than emitting a normal format/argument mismatch, we want to
2839      // add a cast to the recommended type (and correct the format string
2840      // if necessary).
2841      SmallString<16> CastBuf;
2842      llvm::raw_svector_ostream CastFix(CastBuf);
2843      CastFix << "(";
2844      IntendedTy.print(CastFix, S.Context.getPrintingPolicy());
2845      CastFix << ")";
2846
2847      SmallVector<FixItHint,4> Hints;
2848      if (!AT.matchesType(S.Context, IntendedTy))
2849        Hints.push_back(FixItHint::CreateReplacement(SpecRange, os.str()));
2850
2851      if (const CStyleCastExpr *CCast = dyn_cast<CStyleCastExpr>(E)) {
2852        // If there's already a cast present, just replace it.
2853        SourceRange CastRange(CCast->getLParenLoc(), CCast->getRParenLoc());
2854        Hints.push_back(FixItHint::CreateReplacement(CastRange, CastFix.str()));
2855
2856      } else if (!requiresParensToAddCast(E)) {
2857        // If the expression has high enough precedence,
2858        // just write the C-style cast.
2859        Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(),
2860                                                   CastFix.str()));
2861      } else {
2862        // Otherwise, add parens around the expression as well as the cast.
2863        CastFix << "(";
2864        Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(),
2865                                                   CastFix.str()));
2866
2867        SourceLocation After = S.PP.getLocForEndOfToken(E->getLocEnd());
2868        Hints.push_back(FixItHint::CreateInsertion(After, ")"));
2869      }
2870
2871      if (ShouldNotPrintDirectly) {
2872        // The expression has a type that should not be printed directly.
2873        // We extract the name from the typedef because we don't want to show
2874        // the underlying type in the diagnostic.
2875        StringRef Name = cast<TypedefType>(ExprTy)->getDecl()->getName();
2876
2877        EmitFormatDiagnostic(S.PDiag(diag::warn_format_argument_needs_cast)
2878                               << Name << IntendedTy
2879                               << E->getSourceRange(),
2880                             E->getLocStart(), /*IsStringLocation=*/false,
2881                             SpecRange, Hints);
2882      } else {
2883        // In this case, the expression could be printed using a different
2884        // specifier, but we've decided that the specifier is probably correct
2885        // and we should cast instead. Just use the normal warning message.
2886        EmitFormatDiagnostic(
2887          S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
2888            << AT.getRepresentativeTypeName(S.Context) << ExprTy
2889            << E->getSourceRange(),
2890          E->getLocStart(), /*IsStringLocation*/false,
2891          SpecRange, Hints);
2892      }
2893    }
2894  } else {
2895    const CharSourceRange &CSR = getSpecifierRange(StartSpecifier,
2896                                                   SpecifierLen);
2897    // Since the warning for passing non-POD types to variadic functions
2898    // was deferred until now, we emit a warning for non-POD
2899    // arguments here.
2900    if (S.isValidVarArgType(ExprTy) == Sema::VAK_Invalid) {
2901      unsigned DiagKind;
2902      if (ExprTy->isObjCObjectType())
2903        DiagKind = diag::err_cannot_pass_objc_interface_to_vararg_format;
2904      else
2905        DiagKind = diag::warn_non_pod_vararg_with_format_string;
2906
2907      EmitFormatDiagnostic(
2908        S.PDiag(DiagKind)
2909          << S.getLangOpts().CPlusPlus0x
2910          << ExprTy
2911          << CallType
2912          << AT.getRepresentativeTypeName(S.Context)
2913          << CSR
2914          << E->getSourceRange(),
2915        E->getLocStart(), /*IsStringLocation*/false, CSR);
2916
2917      checkForCStrMembers(AT, E, CSR);
2918    } else
2919      EmitFormatDiagnostic(
2920        S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
2921          << AT.getRepresentativeTypeName(S.Context) << ExprTy
2922          << CSR
2923          << E->getSourceRange(),
2924        E->getLocStart(), /*IsStringLocation*/false, CSR);
2925  }
2926
2927  return true;
2928}
2929
2930//===--- CHECK: Scanf format string checking ------------------------------===//
2931
2932namespace {
2933class CheckScanfHandler : public CheckFormatHandler {
2934public:
2935  CheckScanfHandler(Sema &s, const StringLiteral *fexpr,
2936                    const Expr *origFormatExpr, unsigned firstDataArg,
2937                    unsigned numDataArgs, const char *beg, bool hasVAListArg,
2938                    Expr **Args, unsigned NumArgs,
2939                    unsigned formatIdx, bool inFunctionCall,
2940                    Sema::VariadicCallType CallType)
2941  : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
2942                       numDataArgs, beg, hasVAListArg,
2943                       Args, NumArgs, formatIdx, inFunctionCall, CallType)
2944  {}
2945
2946  bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS,
2947                            const char *startSpecifier,
2948                            unsigned specifierLen);
2949
2950  bool HandleInvalidScanfConversionSpecifier(
2951          const analyze_scanf::ScanfSpecifier &FS,
2952          const char *startSpecifier,
2953          unsigned specifierLen);
2954
2955  void HandleIncompleteScanList(const char *start, const char *end);
2956};
2957}
2958
2959void CheckScanfHandler::HandleIncompleteScanList(const char *start,
2960                                                 const char *end) {
2961  EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete),
2962                       getLocationOfByte(end), /*IsStringLocation*/true,
2963                       getSpecifierRange(start, end - start));
2964}
2965
2966bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier(
2967                                        const analyze_scanf::ScanfSpecifier &FS,
2968                                        const char *startSpecifier,
2969                                        unsigned specifierLen) {
2970
2971  const analyze_scanf::ScanfConversionSpecifier &CS =
2972    FS.getConversionSpecifier();
2973
2974  return HandleInvalidConversionSpecifier(FS.getArgIndex(),
2975                                          getLocationOfByte(CS.getStart()),
2976                                          startSpecifier, specifierLen,
2977                                          CS.getStart(), CS.getLength());
2978}
2979
2980bool CheckScanfHandler::HandleScanfSpecifier(
2981                                       const analyze_scanf::ScanfSpecifier &FS,
2982                                       const char *startSpecifier,
2983                                       unsigned specifierLen) {
2984
2985  using namespace analyze_scanf;
2986  using namespace analyze_format_string;
2987
2988  const ScanfConversionSpecifier &CS = FS.getConversionSpecifier();
2989
2990  // Handle case where '%' and '*' don't consume an argument.  These shouldn't
2991  // be used to decide if we are using positional arguments consistently.
2992  if (FS.consumesDataArgument()) {
2993    if (atFirstArg) {
2994      atFirstArg = false;
2995      usesPositionalArgs = FS.usesPositionalArg();
2996    }
2997    else if (usesPositionalArgs != FS.usesPositionalArg()) {
2998      HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()),
2999                                        startSpecifier, specifierLen);
3000      return false;
3001    }
3002  }
3003
3004  // Check if the field with is non-zero.
3005  const OptionalAmount &Amt = FS.getFieldWidth();
3006  if (Amt.getHowSpecified() == OptionalAmount::Constant) {
3007    if (Amt.getConstantAmount() == 0) {
3008      const CharSourceRange &R = getSpecifierRange(Amt.getStart(),
3009                                                   Amt.getConstantLength());
3010      EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width),
3011                           getLocationOfByte(Amt.getStart()),
3012                           /*IsStringLocation*/true, R,
3013                           FixItHint::CreateRemoval(R));
3014    }
3015  }
3016
3017  if (!FS.consumesDataArgument()) {
3018    // FIXME: Technically specifying a precision or field width here
3019    // makes no sense.  Worth issuing a warning at some point.
3020    return true;
3021  }
3022
3023  // Consume the argument.
3024  unsigned argIndex = FS.getArgIndex();
3025  if (argIndex < NumDataArgs) {
3026      // The check to see if the argIndex is valid will come later.
3027      // We set the bit here because we may exit early from this
3028      // function if we encounter some other error.
3029    CoveredArgs.set(argIndex);
3030  }
3031
3032  // Check the length modifier is valid with the given conversion specifier.
3033  if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo()))
3034    HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
3035                                diag::warn_format_nonsensical_length);
3036  else if (!FS.hasStandardLengthModifier())
3037    HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen);
3038  else if (!FS.hasStandardLengthConversionCombination())
3039    HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
3040                                diag::warn_format_non_standard_conversion_spec);
3041
3042  if (!FS.hasStandardConversionSpecifier(S.getLangOpts()))
3043    HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen);
3044
3045  // The remaining checks depend on the data arguments.
3046  if (HasVAListArg)
3047    return true;
3048
3049  if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
3050    return false;
3051
3052  // Check that the argument type matches the format specifier.
3053  const Expr *Ex = getDataArg(argIndex);
3054  if (!Ex)
3055    return true;
3056
3057  const analyze_format_string::ArgType &AT = FS.getArgType(S.Context);
3058  if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType())) {
3059    ScanfSpecifier fixedFS = FS;
3060    bool success = fixedFS.fixType(Ex->getType(), S.getLangOpts(),
3061                                   S.Context);
3062
3063    if (success) {
3064      // Get the fix string from the fixed format specifier.
3065      SmallString<128> buf;
3066      llvm::raw_svector_ostream os(buf);
3067      fixedFS.toString(os);
3068
3069      EmitFormatDiagnostic(
3070        S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
3071          << AT.getRepresentativeTypeName(S.Context) << Ex->getType()
3072          << Ex->getSourceRange(),
3073        Ex->getLocStart(),
3074        /*IsStringLocation*/false,
3075        getSpecifierRange(startSpecifier, specifierLen),
3076        FixItHint::CreateReplacement(
3077          getSpecifierRange(startSpecifier, specifierLen),
3078          os.str()));
3079    } else {
3080      EmitFormatDiagnostic(
3081        S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
3082          << AT.getRepresentativeTypeName(S.Context) << Ex->getType()
3083          << Ex->getSourceRange(),
3084        Ex->getLocStart(),
3085        /*IsStringLocation*/false,
3086        getSpecifierRange(startSpecifier, specifierLen));
3087    }
3088  }
3089
3090  return true;
3091}
3092
3093void Sema::CheckFormatString(const StringLiteral *FExpr,
3094                             const Expr *OrigFormatExpr,
3095                             Expr **Args, unsigned NumArgs,
3096                             bool HasVAListArg, unsigned format_idx,
3097                             unsigned firstDataArg, FormatStringType Type,
3098                             bool inFunctionCall, VariadicCallType CallType) {
3099
3100  // CHECK: is the format string a wide literal?
3101  if (!FExpr->isAscii() && !FExpr->isUTF8()) {
3102    CheckFormatHandler::EmitFormatDiagnostic(
3103      *this, inFunctionCall, Args[format_idx],
3104      PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(),
3105      /*IsStringLocation*/true, OrigFormatExpr->getSourceRange());
3106    return;
3107  }
3108
3109  // Str - The format string.  NOTE: this is NOT null-terminated!
3110  StringRef StrRef = FExpr->getString();
3111  const char *Str = StrRef.data();
3112  unsigned StrLen = StrRef.size();
3113  const unsigned numDataArgs = NumArgs - firstDataArg;
3114
3115  // CHECK: empty format string?
3116  if (StrLen == 0 && numDataArgs > 0) {
3117    CheckFormatHandler::EmitFormatDiagnostic(
3118      *this, inFunctionCall, Args[format_idx],
3119      PDiag(diag::warn_empty_format_string), FExpr->getLocStart(),
3120      /*IsStringLocation*/true, OrigFormatExpr->getSourceRange());
3121    return;
3122  }
3123
3124  if (Type == FST_Printf || Type == FST_NSString) {
3125    CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg,
3126                         numDataArgs, (Type == FST_NSString),
3127                         Str, HasVAListArg, Args, NumArgs, format_idx,
3128                         inFunctionCall, CallType);
3129
3130    if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen,
3131                                                  getLangOpts(),
3132                                                  Context.getTargetInfo()))
3133      H.DoneProcessing();
3134  } else if (Type == FST_Scanf) {
3135    CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, numDataArgs,
3136                        Str, HasVAListArg, Args, NumArgs, format_idx,
3137                        inFunctionCall, CallType);
3138
3139    if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen,
3140                                                 getLangOpts(),
3141                                                 Context.getTargetInfo()))
3142      H.DoneProcessing();
3143  } // TODO: handle other formats
3144}
3145
3146//===--- CHECK: Standard memory functions ---------------------------------===//
3147
3148/// \brief Determine whether the given type is a dynamic class type (e.g.,
3149/// whether it has a vtable).
3150static bool isDynamicClassType(QualType T) {
3151  if (CXXRecordDecl *Record = T->getAsCXXRecordDecl())
3152    if (CXXRecordDecl *Definition = Record->getDefinition())
3153      if (Definition->isDynamicClass())
3154        return true;
3155
3156  return false;
3157}
3158
3159/// \brief If E is a sizeof expression, returns its argument expression,
3160/// otherwise returns NULL.
3161static const Expr *getSizeOfExprArg(const Expr* E) {
3162  if (const UnaryExprOrTypeTraitExpr *SizeOf =
3163      dyn_cast<UnaryExprOrTypeTraitExpr>(E))
3164    if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType())
3165      return SizeOf->getArgumentExpr()->IgnoreParenImpCasts();
3166
3167  return 0;
3168}
3169
3170/// \brief If E is a sizeof expression, returns its argument type.
3171static QualType getSizeOfArgType(const Expr* E) {
3172  if (const UnaryExprOrTypeTraitExpr *SizeOf =
3173      dyn_cast<UnaryExprOrTypeTraitExpr>(E))
3174    if (SizeOf->getKind() == clang::UETT_SizeOf)
3175      return SizeOf->getTypeOfArgument();
3176
3177  return QualType();
3178}
3179
3180/// \brief Check for dangerous or invalid arguments to memset().
3181///
3182/// This issues warnings on known problematic, dangerous or unspecified
3183/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp'
3184/// function calls.
3185///
3186/// \param Call The call expression to diagnose.
3187void Sema::CheckMemaccessArguments(const CallExpr *Call,
3188                                   unsigned BId,
3189                                   IdentifierInfo *FnName) {
3190  assert(BId != 0);
3191
3192  // It is possible to have a non-standard definition of memset.  Validate
3193  // we have enough arguments, and if not, abort further checking.
3194  unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3);
3195  if (Call->getNumArgs() < ExpectedNumArgs)
3196    return;
3197
3198  unsigned LastArg = (BId == Builtin::BImemset ||
3199                      BId == Builtin::BIstrndup ? 1 : 2);
3200  unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2);
3201  const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts();
3202
3203  // We have special checking when the length is a sizeof expression.
3204  QualType SizeOfArgTy = getSizeOfArgType(LenExpr);
3205  const Expr *SizeOfArg = getSizeOfExprArg(LenExpr);
3206  llvm::FoldingSetNodeID SizeOfArgID;
3207
3208  for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) {
3209    const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts();
3210    SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange();
3211
3212    QualType DestTy = Dest->getType();
3213    if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) {
3214      QualType PointeeTy = DestPtrTy->getPointeeType();
3215
3216      // Never warn about void type pointers. This can be used to suppress
3217      // false positives.
3218      if (PointeeTy->isVoidType())
3219        continue;
3220
3221      // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by
3222      // actually comparing the expressions for equality. Because computing the
3223      // expression IDs can be expensive, we only do this if the diagnostic is
3224      // enabled.
3225      if (SizeOfArg &&
3226          Diags.getDiagnosticLevel(diag::warn_sizeof_pointer_expr_memaccess,
3227                                   SizeOfArg->getExprLoc())) {
3228        // We only compute IDs for expressions if the warning is enabled, and
3229        // cache the sizeof arg's ID.
3230        if (SizeOfArgID == llvm::FoldingSetNodeID())
3231          SizeOfArg->Profile(SizeOfArgID, Context, true);
3232        llvm::FoldingSetNodeID DestID;
3233        Dest->Profile(DestID, Context, true);
3234        if (DestID == SizeOfArgID) {
3235          // TODO: For strncpy() and friends, this could suggest sizeof(dst)
3236          //       over sizeof(src) as well.
3237          unsigned ActionIdx = 0; // Default is to suggest dereferencing.
3238          StringRef ReadableName = FnName->getName();
3239
3240          if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest))
3241            if (UnaryOp->getOpcode() == UO_AddrOf)
3242              ActionIdx = 1; // If its an address-of operator, just remove it.
3243          if (Context.getTypeSize(PointeeTy) == Context.getCharWidth())
3244            ActionIdx = 2; // If the pointee's size is sizeof(char),
3245                           // suggest an explicit length.
3246
3247          // If the function is defined as a builtin macro, do not show macro
3248          // expansion.
3249          SourceLocation SL = SizeOfArg->getExprLoc();
3250          SourceRange DSR = Dest->getSourceRange();
3251          SourceRange SSR = SizeOfArg->getSourceRange();
3252          SourceManager &SM  = PP.getSourceManager();
3253
3254          if (SM.isMacroArgExpansion(SL)) {
3255            ReadableName = Lexer::getImmediateMacroName(SL, SM, LangOpts);
3256            SL = SM.getSpellingLoc(SL);
3257            DSR = SourceRange(SM.getSpellingLoc(DSR.getBegin()),
3258                             SM.getSpellingLoc(DSR.getEnd()));
3259            SSR = SourceRange(SM.getSpellingLoc(SSR.getBegin()),
3260                             SM.getSpellingLoc(SSR.getEnd()));
3261          }
3262
3263          DiagRuntimeBehavior(SL, SizeOfArg,
3264                              PDiag(diag::warn_sizeof_pointer_expr_memaccess)
3265                                << ReadableName
3266                                << PointeeTy
3267                                << DestTy
3268                                << DSR
3269                                << SSR);
3270          DiagRuntimeBehavior(SL, SizeOfArg,
3271                         PDiag(diag::warn_sizeof_pointer_expr_memaccess_note)
3272                                << ActionIdx
3273                                << SSR);
3274
3275          break;
3276        }
3277      }
3278
3279      // Also check for cases where the sizeof argument is the exact same
3280      // type as the memory argument, and where it points to a user-defined
3281      // record type.
3282      if (SizeOfArgTy != QualType()) {
3283        if (PointeeTy->isRecordType() &&
3284            Context.typesAreCompatible(SizeOfArgTy, DestTy)) {
3285          DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest,
3286                              PDiag(diag::warn_sizeof_pointer_type_memaccess)
3287                                << FnName << SizeOfArgTy << ArgIdx
3288                                << PointeeTy << Dest->getSourceRange()
3289                                << LenExpr->getSourceRange());
3290          break;
3291        }
3292      }
3293
3294      // Always complain about dynamic classes.
3295      if (isDynamicClassType(PointeeTy)) {
3296
3297        unsigned OperationType = 0;
3298        // "overwritten" if we're warning about the destination for any call
3299        // but memcmp; otherwise a verb appropriate to the call.
3300        if (ArgIdx != 0 || BId == Builtin::BImemcmp) {
3301          if (BId == Builtin::BImemcpy)
3302            OperationType = 1;
3303          else if(BId == Builtin::BImemmove)
3304            OperationType = 2;
3305          else if (BId == Builtin::BImemcmp)
3306            OperationType = 3;
3307        }
3308
3309        DiagRuntimeBehavior(
3310          Dest->getExprLoc(), Dest,
3311          PDiag(diag::warn_dyn_class_memaccess)
3312            << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx)
3313            << FnName << PointeeTy
3314            << OperationType
3315            << Call->getCallee()->getSourceRange());
3316      } else if (PointeeTy.hasNonTrivialObjCLifetime() &&
3317               BId != Builtin::BImemset)
3318        DiagRuntimeBehavior(
3319          Dest->getExprLoc(), Dest,
3320          PDiag(diag::warn_arc_object_memaccess)
3321            << ArgIdx << FnName << PointeeTy
3322            << Call->getCallee()->getSourceRange());
3323      else
3324        continue;
3325
3326      DiagRuntimeBehavior(
3327        Dest->getExprLoc(), Dest,
3328        PDiag(diag::note_bad_memaccess_silence)
3329          << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)"));
3330      break;
3331    }
3332  }
3333}
3334
3335// A little helper routine: ignore addition and subtraction of integer literals.
3336// This intentionally does not ignore all integer constant expressions because
3337// we don't want to remove sizeof().
3338static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) {
3339  Ex = Ex->IgnoreParenCasts();
3340
3341  for (;;) {
3342    const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex);
3343    if (!BO || !BO->isAdditiveOp())
3344      break;
3345
3346    const Expr *RHS = BO->getRHS()->IgnoreParenCasts();
3347    const Expr *LHS = BO->getLHS()->IgnoreParenCasts();
3348
3349    if (isa<IntegerLiteral>(RHS))
3350      Ex = LHS;
3351    else if (isa<IntegerLiteral>(LHS))
3352      Ex = RHS;
3353    else
3354      break;
3355  }
3356
3357  return Ex;
3358}
3359
3360static bool isConstantSizeArrayWithMoreThanOneElement(QualType Ty,
3361                                                      ASTContext &Context) {
3362  // Only handle constant-sized or VLAs, but not flexible members.
3363  if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(Ty)) {
3364    // Only issue the FIXIT for arrays of size > 1.
3365    if (CAT->getSize().getSExtValue() <= 1)
3366      return false;
3367  } else if (!Ty->isVariableArrayType()) {
3368    return false;
3369  }
3370  return true;
3371}
3372
3373// Warn if the user has made the 'size' argument to strlcpy or strlcat
3374// be the size of the source, instead of the destination.
3375void Sema::CheckStrlcpycatArguments(const CallExpr *Call,
3376                                    IdentifierInfo *FnName) {
3377
3378  // Don't crash if the user has the wrong number of arguments
3379  if (Call->getNumArgs() != 3)
3380    return;
3381
3382  const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context);
3383  const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context);
3384  const Expr *CompareWithSrc = NULL;
3385
3386  // Look for 'strlcpy(dst, x, sizeof(x))'
3387  if (const Expr *Ex = getSizeOfExprArg(SizeArg))
3388    CompareWithSrc = Ex;
3389  else {
3390    // Look for 'strlcpy(dst, x, strlen(x))'
3391    if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) {
3392      if (SizeCall->isBuiltinCall() == Builtin::BIstrlen
3393          && SizeCall->getNumArgs() == 1)
3394        CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context);
3395    }
3396  }
3397
3398  if (!CompareWithSrc)
3399    return;
3400
3401  // Determine if the argument to sizeof/strlen is equal to the source
3402  // argument.  In principle there's all kinds of things you could do
3403  // here, for instance creating an == expression and evaluating it with
3404  // EvaluateAsBooleanCondition, but this uses a more direct technique:
3405  const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg);
3406  if (!SrcArgDRE)
3407    return;
3408
3409  const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc);
3410  if (!CompareWithSrcDRE ||
3411      SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl())
3412    return;
3413
3414  const Expr *OriginalSizeArg = Call->getArg(2);
3415  Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size)
3416    << OriginalSizeArg->getSourceRange() << FnName;
3417
3418  // Output a FIXIT hint if the destination is an array (rather than a
3419  // pointer to an array).  This could be enhanced to handle some
3420  // pointers if we know the actual size, like if DstArg is 'array+2'
3421  // we could say 'sizeof(array)-2'.
3422  const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts();
3423  if (!isConstantSizeArrayWithMoreThanOneElement(DstArg->getType(), Context))
3424    return;
3425
3426  SmallString<128> sizeString;
3427  llvm::raw_svector_ostream OS(sizeString);
3428  OS << "sizeof(";
3429  DstArg->printPretty(OS, 0, getPrintingPolicy());
3430  OS << ")";
3431
3432  Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size)
3433    << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(),
3434                                    OS.str());
3435}
3436
3437/// Check if two expressions refer to the same declaration.
3438static bool referToTheSameDecl(const Expr *E1, const Expr *E2) {
3439  if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1))
3440    if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2))
3441      return D1->getDecl() == D2->getDecl();
3442  return false;
3443}
3444
3445static const Expr *getStrlenExprArg(const Expr *E) {
3446  if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
3447    const FunctionDecl *FD = CE->getDirectCallee();
3448    if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen)
3449      return 0;
3450    return CE->getArg(0)->IgnoreParenCasts();
3451  }
3452  return 0;
3453}
3454
3455// Warn on anti-patterns as the 'size' argument to strncat.
3456// The correct size argument should look like following:
3457//   strncat(dst, src, sizeof(dst) - strlen(dest) - 1);
3458void Sema::CheckStrncatArguments(const CallExpr *CE,
3459                                 IdentifierInfo *FnName) {
3460  // Don't crash if the user has the wrong number of arguments.
3461  if (CE->getNumArgs() < 3)
3462    return;
3463  const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts();
3464  const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts();
3465  const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts();
3466
3467  // Identify common expressions, which are wrongly used as the size argument
3468  // to strncat and may lead to buffer overflows.
3469  unsigned PatternType = 0;
3470  if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) {
3471    // - sizeof(dst)
3472    if (referToTheSameDecl(SizeOfArg, DstArg))
3473      PatternType = 1;
3474    // - sizeof(src)
3475    else if (referToTheSameDecl(SizeOfArg, SrcArg))
3476      PatternType = 2;
3477  } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) {
3478    if (BE->getOpcode() == BO_Sub) {
3479      const Expr *L = BE->getLHS()->IgnoreParenCasts();
3480      const Expr *R = BE->getRHS()->IgnoreParenCasts();
3481      // - sizeof(dst) - strlen(dst)
3482      if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) &&
3483          referToTheSameDecl(DstArg, getStrlenExprArg(R)))
3484        PatternType = 1;
3485      // - sizeof(src) - (anything)
3486      else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L)))
3487        PatternType = 2;
3488    }
3489  }
3490
3491  if (PatternType == 0)
3492    return;
3493
3494  // Generate the diagnostic.
3495  SourceLocation SL = LenArg->getLocStart();
3496  SourceRange SR = LenArg->getSourceRange();
3497  SourceManager &SM  = PP.getSourceManager();
3498
3499  // If the function is defined as a builtin macro, do not show macro expansion.
3500  if (SM.isMacroArgExpansion(SL)) {
3501    SL = SM.getSpellingLoc(SL);
3502    SR = SourceRange(SM.getSpellingLoc(SR.getBegin()),
3503                     SM.getSpellingLoc(SR.getEnd()));
3504  }
3505
3506  // Check if the destination is an array (rather than a pointer to an array).
3507  QualType DstTy = DstArg->getType();
3508  bool isKnownSizeArray = isConstantSizeArrayWithMoreThanOneElement(DstTy,
3509                                                                    Context);
3510  if (!isKnownSizeArray) {
3511    if (PatternType == 1)
3512      Diag(SL, diag::warn_strncat_wrong_size) << SR;
3513    else
3514      Diag(SL, diag::warn_strncat_src_size) << SR;
3515    return;
3516  }
3517
3518  if (PatternType == 1)
3519    Diag(SL, diag::warn_strncat_large_size) << SR;
3520  else
3521    Diag(SL, diag::warn_strncat_src_size) << SR;
3522
3523  SmallString<128> sizeString;
3524  llvm::raw_svector_ostream OS(sizeString);
3525  OS << "sizeof(";
3526  DstArg->printPretty(OS, 0, getPrintingPolicy());
3527  OS << ") - ";
3528  OS << "strlen(";
3529  DstArg->printPretty(OS, 0, getPrintingPolicy());
3530  OS << ") - 1";
3531
3532  Diag(SL, diag::note_strncat_wrong_size)
3533    << FixItHint::CreateReplacement(SR, OS.str());
3534}
3535
3536//===--- CHECK: Return Address of Stack Variable --------------------------===//
3537
3538static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
3539                     Decl *ParentDecl);
3540static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars,
3541                      Decl *ParentDecl);
3542
3543/// CheckReturnStackAddr - Check if a return statement returns the address
3544///   of a stack variable.
3545void
3546Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType,
3547                           SourceLocation ReturnLoc) {
3548
3549  Expr *stackE = 0;
3550  SmallVector<DeclRefExpr *, 8> refVars;
3551
3552  // Perform checking for returned stack addresses, local blocks,
3553  // label addresses or references to temporaries.
3554  if (lhsType->isPointerType() ||
3555      (!getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) {
3556    stackE = EvalAddr(RetValExp, refVars, /*ParentDecl=*/0);
3557  } else if (lhsType->isReferenceType()) {
3558    stackE = EvalVal(RetValExp, refVars, /*ParentDecl=*/0);
3559  }
3560
3561  if (stackE == 0)
3562    return; // Nothing suspicious was found.
3563
3564  SourceLocation diagLoc;
3565  SourceRange diagRange;
3566  if (refVars.empty()) {
3567    diagLoc = stackE->getLocStart();
3568    diagRange = stackE->getSourceRange();
3569  } else {
3570    // We followed through a reference variable. 'stackE' contains the
3571    // problematic expression but we will warn at the return statement pointing
3572    // at the reference variable. We will later display the "trail" of
3573    // reference variables using notes.
3574    diagLoc = refVars[0]->getLocStart();
3575    diagRange = refVars[0]->getSourceRange();
3576  }
3577
3578  if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var.
3579    Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref
3580                                             : diag::warn_ret_stack_addr)
3581     << DR->getDecl()->getDeclName() << diagRange;
3582  } else if (isa<BlockExpr>(stackE)) { // local block.
3583    Diag(diagLoc, diag::err_ret_local_block) << diagRange;
3584  } else if (isa<AddrLabelExpr>(stackE)) { // address of label.
3585    Diag(diagLoc, diag::warn_ret_addr_label) << diagRange;
3586  } else { // local temporary.
3587    Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref
3588                                             : diag::warn_ret_local_temp_addr)
3589     << diagRange;
3590  }
3591
3592  // Display the "trail" of reference variables that we followed until we
3593  // found the problematic expression using notes.
3594  for (unsigned i = 0, e = refVars.size(); i != e; ++i) {
3595    VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl());
3596    // If this var binds to another reference var, show the range of the next
3597    // var, otherwise the var binds to the problematic expression, in which case
3598    // show the range of the expression.
3599    SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange()
3600                                  : stackE->getSourceRange();
3601    Diag(VD->getLocation(), diag::note_ref_var_local_bind)
3602      << VD->getDeclName() << range;
3603  }
3604}
3605
3606/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that
3607///  check if the expression in a return statement evaluates to an address
3608///  to a location on the stack, a local block, an address of a label, or a
3609///  reference to local temporary. The recursion is used to traverse the
3610///  AST of the return expression, with recursion backtracking when we
3611///  encounter a subexpression that (1) clearly does not lead to one of the
3612///  above problematic expressions (2) is something we cannot determine leads to
3613///  a problematic expression based on such local checking.
3614///
3615///  Both EvalAddr and EvalVal follow through reference variables to evaluate
3616///  the expression that they point to. Such variables are added to the
3617///  'refVars' vector so that we know what the reference variable "trail" was.
3618///
3619///  EvalAddr processes expressions that are pointers that are used as
3620///  references (and not L-values).  EvalVal handles all other values.
3621///  At the base case of the recursion is a check for the above problematic
3622///  expressions.
3623///
3624///  This implementation handles:
3625///
3626///   * pointer-to-pointer casts
3627///   * implicit conversions from array references to pointers
3628///   * taking the address of fields
3629///   * arbitrary interplay between "&" and "*" operators
3630///   * pointer arithmetic from an address of a stack variable
3631///   * taking the address of an array element where the array is on the stack
3632static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
3633                      Decl *ParentDecl) {
3634  if (E->isTypeDependent())
3635      return NULL;
3636
3637  // We should only be called for evaluating pointer expressions.
3638  assert((E->getType()->isAnyPointerType() ||
3639          E->getType()->isBlockPointerType() ||
3640          E->getType()->isObjCQualifiedIdType()) &&
3641         "EvalAddr only works on pointers");
3642
3643  E = E->IgnoreParens();
3644
3645  // Our "symbolic interpreter" is just a dispatch off the currently
3646  // viewed AST node.  We then recursively traverse the AST by calling
3647  // EvalAddr and EvalVal appropriately.
3648  switch (E->getStmtClass()) {
3649  case Stmt::DeclRefExprClass: {
3650    DeclRefExpr *DR = cast<DeclRefExpr>(E);
3651
3652    if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl()))
3653      // If this is a reference variable, follow through to the expression that
3654      // it points to.
3655      if (V->hasLocalStorage() &&
3656          V->getType()->isReferenceType() && V->hasInit()) {
3657        // Add the reference variable to the "trail".
3658        refVars.push_back(DR);
3659        return EvalAddr(V->getInit(), refVars, ParentDecl);
3660      }
3661
3662    return NULL;
3663  }
3664
3665  case Stmt::UnaryOperatorClass: {
3666    // The only unary operator that make sense to handle here
3667    // is AddrOf.  All others don't make sense as pointers.
3668    UnaryOperator *U = cast<UnaryOperator>(E);
3669
3670    if (U->getOpcode() == UO_AddrOf)
3671      return EvalVal(U->getSubExpr(), refVars, ParentDecl);
3672    else
3673      return NULL;
3674  }
3675
3676  case Stmt::BinaryOperatorClass: {
3677    // Handle pointer arithmetic.  All other binary operators are not valid
3678    // in this context.
3679    BinaryOperator *B = cast<BinaryOperator>(E);
3680    BinaryOperatorKind op = B->getOpcode();
3681
3682    if (op != BO_Add && op != BO_Sub)
3683      return NULL;
3684
3685    Expr *Base = B->getLHS();
3686
3687    // Determine which argument is the real pointer base.  It could be
3688    // the RHS argument instead of the LHS.
3689    if (!Base->getType()->isPointerType()) Base = B->getRHS();
3690
3691    assert (Base->getType()->isPointerType());
3692    return EvalAddr(Base, refVars, ParentDecl);
3693  }
3694
3695  // For conditional operators we need to see if either the LHS or RHS are
3696  // valid DeclRefExpr*s.  If one of them is valid, we return it.
3697  case Stmt::ConditionalOperatorClass: {
3698    ConditionalOperator *C = cast<ConditionalOperator>(E);
3699
3700    // Handle the GNU extension for missing LHS.
3701    if (Expr *lhsExpr = C->getLHS()) {
3702    // In C++, we can have a throw-expression, which has 'void' type.
3703      if (!lhsExpr->getType()->isVoidType())
3704        if (Expr* LHS = EvalAddr(lhsExpr, refVars, ParentDecl))
3705          return LHS;
3706    }
3707
3708    // In C++, we can have a throw-expression, which has 'void' type.
3709    if (C->getRHS()->getType()->isVoidType())
3710      return NULL;
3711
3712    return EvalAddr(C->getRHS(), refVars, ParentDecl);
3713  }
3714
3715  case Stmt::BlockExprClass:
3716    if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures())
3717      return E; // local block.
3718    return NULL;
3719
3720  case Stmt::AddrLabelExprClass:
3721    return E; // address of label.
3722
3723  case Stmt::ExprWithCleanupsClass:
3724    return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,
3725                    ParentDecl);
3726
3727  // For casts, we need to handle conversions from arrays to
3728  // pointer values, and pointer-to-pointer conversions.
3729  case Stmt::ImplicitCastExprClass:
3730  case Stmt::CStyleCastExprClass:
3731  case Stmt::CXXFunctionalCastExprClass:
3732  case Stmt::ObjCBridgedCastExprClass:
3733  case Stmt::CXXStaticCastExprClass:
3734  case Stmt::CXXDynamicCastExprClass:
3735  case Stmt::CXXConstCastExprClass:
3736  case Stmt::CXXReinterpretCastExprClass: {
3737    Expr* SubExpr = cast<CastExpr>(E)->getSubExpr();
3738    switch (cast<CastExpr>(E)->getCastKind()) {
3739    case CK_BitCast:
3740    case CK_LValueToRValue:
3741    case CK_NoOp:
3742    case CK_BaseToDerived:
3743    case CK_DerivedToBase:
3744    case CK_UncheckedDerivedToBase:
3745    case CK_Dynamic:
3746    case CK_CPointerToObjCPointerCast:
3747    case CK_BlockPointerToObjCPointerCast:
3748    case CK_AnyPointerToBlockPointerCast:
3749      return EvalAddr(SubExpr, refVars, ParentDecl);
3750
3751    case CK_ArrayToPointerDecay:
3752      return EvalVal(SubExpr, refVars, ParentDecl);
3753
3754    default:
3755      return 0;
3756    }
3757  }
3758
3759  case Stmt::MaterializeTemporaryExprClass:
3760    if (Expr *Result = EvalAddr(
3761                         cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
3762                                refVars, ParentDecl))
3763      return Result;
3764
3765    return E;
3766
3767  // Everything else: we simply don't reason about them.
3768  default:
3769    return NULL;
3770  }
3771}
3772
3773
3774///  EvalVal - This function is complements EvalAddr in the mutual recursion.
3775///   See the comments for EvalAddr for more details.
3776static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
3777                     Decl *ParentDecl) {
3778do {
3779  // We should only be called for evaluating non-pointer expressions, or
3780  // expressions with a pointer type that are not used as references but instead
3781  // are l-values (e.g., DeclRefExpr with a pointer type).
3782
3783  // Our "symbolic interpreter" is just a dispatch off the currently
3784  // viewed AST node.  We then recursively traverse the AST by calling
3785  // EvalAddr and EvalVal appropriately.
3786
3787  E = E->IgnoreParens();
3788  switch (E->getStmtClass()) {
3789  case Stmt::ImplicitCastExprClass: {
3790    ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E);
3791    if (IE->getValueKind() == VK_LValue) {
3792      E = IE->getSubExpr();
3793      continue;
3794    }
3795    return NULL;
3796  }
3797
3798  case Stmt::ExprWithCleanupsClass:
3799    return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,ParentDecl);
3800
3801  case Stmt::DeclRefExprClass: {
3802    // When we hit a DeclRefExpr we are looking at code that refers to a
3803    // variable's name. If it's not a reference variable we check if it has
3804    // local storage within the function, and if so, return the expression.
3805    DeclRefExpr *DR = cast<DeclRefExpr>(E);
3806
3807    if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) {
3808      // Check if it refers to itself, e.g. "int& i = i;".
3809      if (V == ParentDecl)
3810        return DR;
3811
3812      if (V->hasLocalStorage()) {
3813        if (!V->getType()->isReferenceType())
3814          return DR;
3815
3816        // Reference variable, follow through to the expression that
3817        // it points to.
3818        if (V->hasInit()) {
3819          // Add the reference variable to the "trail".
3820          refVars.push_back(DR);
3821          return EvalVal(V->getInit(), refVars, V);
3822        }
3823      }
3824    }
3825
3826    return NULL;
3827  }
3828
3829  case Stmt::UnaryOperatorClass: {
3830    // The only unary operator that make sense to handle here
3831    // is Deref.  All others don't resolve to a "name."  This includes
3832    // handling all sorts of rvalues passed to a unary operator.
3833    UnaryOperator *U = cast<UnaryOperator>(E);
3834
3835    if (U->getOpcode() == UO_Deref)
3836      return EvalAddr(U->getSubExpr(), refVars, ParentDecl);
3837
3838    return NULL;
3839  }
3840
3841  case Stmt::ArraySubscriptExprClass: {
3842    // Array subscripts are potential references to data on the stack.  We
3843    // retrieve the DeclRefExpr* for the array variable if it indeed
3844    // has local storage.
3845    return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars,ParentDecl);
3846  }
3847
3848  case Stmt::ConditionalOperatorClass: {
3849    // For conditional operators we need to see if either the LHS or RHS are
3850    // non-NULL Expr's.  If one is non-NULL, we return it.
3851    ConditionalOperator *C = cast<ConditionalOperator>(E);
3852
3853    // Handle the GNU extension for missing LHS.
3854    if (Expr *lhsExpr = C->getLHS())
3855      if (Expr *LHS = EvalVal(lhsExpr, refVars, ParentDecl))
3856        return LHS;
3857
3858    return EvalVal(C->getRHS(), refVars, ParentDecl);
3859  }
3860
3861  // Accesses to members are potential references to data on the stack.
3862  case Stmt::MemberExprClass: {
3863    MemberExpr *M = cast<MemberExpr>(E);
3864
3865    // Check for indirect access.  We only want direct field accesses.
3866    if (M->isArrow())
3867      return NULL;
3868
3869    // Check whether the member type is itself a reference, in which case
3870    // we're not going to refer to the member, but to what the member refers to.
3871    if (M->getMemberDecl()->getType()->isReferenceType())
3872      return NULL;
3873
3874    return EvalVal(M->getBase(), refVars, ParentDecl);
3875  }
3876
3877  case Stmt::MaterializeTemporaryExprClass:
3878    if (Expr *Result = EvalVal(
3879                          cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
3880                               refVars, ParentDecl))
3881      return Result;
3882
3883    return E;
3884
3885  default:
3886    // Check that we don't return or take the address of a reference to a
3887    // temporary. This is only useful in C++.
3888    if (!E->isTypeDependent() && E->isRValue())
3889      return E;
3890
3891    // Everything else: we simply don't reason about them.
3892    return NULL;
3893  }
3894} while (true);
3895}
3896
3897//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===//
3898
3899/// Check for comparisons of floating point operands using != and ==.
3900/// Issue a warning if these are no self-comparisons, as they are not likely
3901/// to do what the programmer intended.
3902void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) {
3903  Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts();
3904  Expr* RightExprSansParen = RHS->IgnoreParenImpCasts();
3905
3906  // Special case: check for x == x (which is OK).
3907  // Do not emit warnings for such cases.
3908  if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen))
3909    if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen))
3910      if (DRL->getDecl() == DRR->getDecl())
3911        return;
3912
3913
3914  // Special case: check for comparisons against literals that can be exactly
3915  //  represented by APFloat.  In such cases, do not emit a warning.  This
3916  //  is a heuristic: often comparison against such literals are used to
3917  //  detect if a value in a variable has not changed.  This clearly can
3918  //  lead to false negatives.
3919  if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) {
3920    if (FLL->isExact())
3921      return;
3922  } else
3923    if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen))
3924      if (FLR->isExact())
3925        return;
3926
3927  // Check for comparisons with builtin types.
3928  if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen))
3929    if (CL->isBuiltinCall())
3930      return;
3931
3932  if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen))
3933    if (CR->isBuiltinCall())
3934      return;
3935
3936  // Emit the diagnostic.
3937  Diag(Loc, diag::warn_floatingpoint_eq)
3938    << LHS->getSourceRange() << RHS->getSourceRange();
3939}
3940
3941//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===//
3942//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===//
3943
3944namespace {
3945
3946/// Structure recording the 'active' range of an integer-valued
3947/// expression.
3948struct IntRange {
3949  /// The number of bits active in the int.
3950  unsigned Width;
3951
3952  /// True if the int is known not to have negative values.
3953  bool NonNegative;
3954
3955  IntRange(unsigned Width, bool NonNegative)
3956    : Width(Width), NonNegative(NonNegative)
3957  {}
3958
3959  /// Returns the range of the bool type.
3960  static IntRange forBoolType() {
3961    return IntRange(1, true);
3962  }
3963
3964  /// Returns the range of an opaque value of the given integral type.
3965  static IntRange forValueOfType(ASTContext &C, QualType T) {
3966    return forValueOfCanonicalType(C,
3967                          T->getCanonicalTypeInternal().getTypePtr());
3968  }
3969
3970  /// Returns the range of an opaque value of a canonical integral type.
3971  static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) {
3972    assert(T->isCanonicalUnqualified());
3973
3974    if (const VectorType *VT = dyn_cast<VectorType>(T))
3975      T = VT->getElementType().getTypePtr();
3976    if (const ComplexType *CT = dyn_cast<ComplexType>(T))
3977      T = CT->getElementType().getTypePtr();
3978
3979    // For enum types, use the known bit width of the enumerators.
3980    if (const EnumType *ET = dyn_cast<EnumType>(T)) {
3981      EnumDecl *Enum = ET->getDecl();
3982      if (!Enum->isCompleteDefinition())
3983        return IntRange(C.getIntWidth(QualType(T, 0)), false);
3984
3985      unsigned NumPositive = Enum->getNumPositiveBits();
3986      unsigned NumNegative = Enum->getNumNegativeBits();
3987
3988      if (NumNegative == 0)
3989        return IntRange(NumPositive, true/*NonNegative*/);
3990      else
3991        return IntRange(std::max(NumPositive + 1, NumNegative),
3992                        false/*NonNegative*/);
3993    }
3994
3995    const BuiltinType *BT = cast<BuiltinType>(T);
3996    assert(BT->isInteger());
3997
3998    return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
3999  }
4000
4001  /// Returns the "target" range of a canonical integral type, i.e.
4002  /// the range of values expressible in the type.
4003  ///
4004  /// This matches forValueOfCanonicalType except that enums have the
4005  /// full range of their type, not the range of their enumerators.
4006  static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) {
4007    assert(T->isCanonicalUnqualified());
4008
4009    if (const VectorType *VT = dyn_cast<VectorType>(T))
4010      T = VT->getElementType().getTypePtr();
4011    if (const ComplexType *CT = dyn_cast<ComplexType>(T))
4012      T = CT->getElementType().getTypePtr();
4013    if (const EnumType *ET = dyn_cast<EnumType>(T))
4014      T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr();
4015
4016    const BuiltinType *BT = cast<BuiltinType>(T);
4017    assert(BT->isInteger());
4018
4019    return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
4020  }
4021
4022  /// Returns the supremum of two ranges: i.e. their conservative merge.
4023  static IntRange join(IntRange L, IntRange R) {
4024    return IntRange(std::max(L.Width, R.Width),
4025                    L.NonNegative && R.NonNegative);
4026  }
4027
4028  /// Returns the infinum of two ranges: i.e. their aggressive merge.
4029  static IntRange meet(IntRange L, IntRange R) {
4030    return IntRange(std::min(L.Width, R.Width),
4031                    L.NonNegative || R.NonNegative);
4032  }
4033};
4034
4035static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value,
4036                              unsigned MaxWidth) {
4037  if (value.isSigned() && value.isNegative())
4038    return IntRange(value.getMinSignedBits(), false);
4039
4040  if (value.getBitWidth() > MaxWidth)
4041    value = value.trunc(MaxWidth);
4042
4043  // isNonNegative() just checks the sign bit without considering
4044  // signedness.
4045  return IntRange(value.getActiveBits(), true);
4046}
4047
4048static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty,
4049                              unsigned MaxWidth) {
4050  if (result.isInt())
4051    return GetValueRange(C, result.getInt(), MaxWidth);
4052
4053  if (result.isVector()) {
4054    IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth);
4055    for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) {
4056      IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth);
4057      R = IntRange::join(R, El);
4058    }
4059    return R;
4060  }
4061
4062  if (result.isComplexInt()) {
4063    IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth);
4064    IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth);
4065    return IntRange::join(R, I);
4066  }
4067
4068  // This can happen with lossless casts to intptr_t of "based" lvalues.
4069  // Assume it might use arbitrary bits.
4070  // FIXME: The only reason we need to pass the type in here is to get
4071  // the sign right on this one case.  It would be nice if APValue
4072  // preserved this.
4073  assert(result.isLValue() || result.isAddrLabelDiff());
4074  return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType());
4075}
4076
4077/// Pseudo-evaluate the given integer expression, estimating the
4078/// range of values it might take.
4079///
4080/// \param MaxWidth - the width to which the value will be truncated
4081static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) {
4082  E = E->IgnoreParens();
4083
4084  // Try a full evaluation first.
4085  Expr::EvalResult result;
4086  if (E->EvaluateAsRValue(result, C))
4087    return GetValueRange(C, result.Val, E->getType(), MaxWidth);
4088
4089  // I think we only want to look through implicit casts here; if the
4090  // user has an explicit widening cast, we should treat the value as
4091  // being of the new, wider type.
4092  if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) {
4093    if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue)
4094      return GetExprRange(C, CE->getSubExpr(), MaxWidth);
4095
4096    IntRange OutputTypeRange = IntRange::forValueOfType(C, CE->getType());
4097
4098    bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast);
4099
4100    // Assume that non-integer casts can span the full range of the type.
4101    if (!isIntegerCast)
4102      return OutputTypeRange;
4103
4104    IntRange SubRange
4105      = GetExprRange(C, CE->getSubExpr(),
4106                     std::min(MaxWidth, OutputTypeRange.Width));
4107
4108    // Bail out if the subexpr's range is as wide as the cast type.
4109    if (SubRange.Width >= OutputTypeRange.Width)
4110      return OutputTypeRange;
4111
4112    // Otherwise, we take the smaller width, and we're non-negative if
4113    // either the output type or the subexpr is.
4114    return IntRange(SubRange.Width,
4115                    SubRange.NonNegative || OutputTypeRange.NonNegative);
4116  }
4117
4118  if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
4119    // If we can fold the condition, just take that operand.
4120    bool CondResult;
4121    if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C))
4122      return GetExprRange(C, CondResult ? CO->getTrueExpr()
4123                                        : CO->getFalseExpr(),
4124                          MaxWidth);
4125
4126    // Otherwise, conservatively merge.
4127    IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth);
4128    IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth);
4129    return IntRange::join(L, R);
4130  }
4131
4132  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
4133    switch (BO->getOpcode()) {
4134
4135    // Boolean-valued operations are single-bit and positive.
4136    case BO_LAnd:
4137    case BO_LOr:
4138    case BO_LT:
4139    case BO_GT:
4140    case BO_LE:
4141    case BO_GE:
4142    case BO_EQ:
4143    case BO_NE:
4144      return IntRange::forBoolType();
4145
4146    // The type of the assignments is the type of the LHS, so the RHS
4147    // is not necessarily the same type.
4148    case BO_MulAssign:
4149    case BO_DivAssign:
4150    case BO_RemAssign:
4151    case BO_AddAssign:
4152    case BO_SubAssign:
4153    case BO_XorAssign:
4154    case BO_OrAssign:
4155      // TODO: bitfields?
4156      return IntRange::forValueOfType(C, E->getType());
4157
4158    // Simple assignments just pass through the RHS, which will have
4159    // been coerced to the LHS type.
4160    case BO_Assign:
4161      // TODO: bitfields?
4162      return GetExprRange(C, BO->getRHS(), MaxWidth);
4163
4164    // Operations with opaque sources are black-listed.
4165    case BO_PtrMemD:
4166    case BO_PtrMemI:
4167      return IntRange::forValueOfType(C, E->getType());
4168
4169    // Bitwise-and uses the *infinum* of the two source ranges.
4170    case BO_And:
4171    case BO_AndAssign:
4172      return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth),
4173                            GetExprRange(C, BO->getRHS(), MaxWidth));
4174
4175    // Left shift gets black-listed based on a judgement call.
4176    case BO_Shl:
4177      // ...except that we want to treat '1 << (blah)' as logically
4178      // positive.  It's an important idiom.
4179      if (IntegerLiteral *I
4180            = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) {
4181        if (I->getValue() == 1) {
4182          IntRange R = IntRange::forValueOfType(C, E->getType());
4183          return IntRange(R.Width, /*NonNegative*/ true);
4184        }
4185      }
4186      // fallthrough
4187
4188    case BO_ShlAssign:
4189      return IntRange::forValueOfType(C, E->getType());
4190
4191    // Right shift by a constant can narrow its left argument.
4192    case BO_Shr:
4193    case BO_ShrAssign: {
4194      IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
4195
4196      // If the shift amount is a positive constant, drop the width by
4197      // that much.
4198      llvm::APSInt shift;
4199      if (BO->getRHS()->isIntegerConstantExpr(shift, C) &&
4200          shift.isNonNegative()) {
4201        unsigned zext = shift.getZExtValue();
4202        if (zext >= L.Width)
4203          L.Width = (L.NonNegative ? 0 : 1);
4204        else
4205          L.Width -= zext;
4206      }
4207
4208      return L;
4209    }
4210
4211    // Comma acts as its right operand.
4212    case BO_Comma:
4213      return GetExprRange(C, BO->getRHS(), MaxWidth);
4214
4215    // Black-list pointer subtractions.
4216    case BO_Sub:
4217      if (BO->getLHS()->getType()->isPointerType())
4218        return IntRange::forValueOfType(C, E->getType());
4219      break;
4220
4221    // The width of a division result is mostly determined by the size
4222    // of the LHS.
4223    case BO_Div: {
4224      // Don't 'pre-truncate' the operands.
4225      unsigned opWidth = C.getIntWidth(E->getType());
4226      IntRange L = GetExprRange(C, BO->getLHS(), opWidth);
4227
4228      // If the divisor is constant, use that.
4229      llvm::APSInt divisor;
4230      if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) {
4231        unsigned log2 = divisor.logBase2(); // floor(log_2(divisor))
4232        if (log2 >= L.Width)
4233          L.Width = (L.NonNegative ? 0 : 1);
4234        else
4235          L.Width = std::min(L.Width - log2, MaxWidth);
4236        return L;
4237      }
4238
4239      // Otherwise, just use the LHS's width.
4240      IntRange R = GetExprRange(C, BO->getRHS(), opWidth);
4241      return IntRange(L.Width, L.NonNegative && R.NonNegative);
4242    }
4243
4244    // The result of a remainder can't be larger than the result of
4245    // either side.
4246    case BO_Rem: {
4247      // Don't 'pre-truncate' the operands.
4248      unsigned opWidth = C.getIntWidth(E->getType());
4249      IntRange L = GetExprRange(C, BO->getLHS(), opWidth);
4250      IntRange R = GetExprRange(C, BO->getRHS(), opWidth);
4251
4252      IntRange meet = IntRange::meet(L, R);
4253      meet.Width = std::min(meet.Width, MaxWidth);
4254      return meet;
4255    }
4256
4257    // The default behavior is okay for these.
4258    case BO_Mul:
4259    case BO_Add:
4260    case BO_Xor:
4261    case BO_Or:
4262      break;
4263    }
4264
4265    // The default case is to treat the operation as if it were closed
4266    // on the narrowest type that encompasses both operands.
4267    IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
4268    IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth);
4269    return IntRange::join(L, R);
4270  }
4271
4272  if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
4273    switch (UO->getOpcode()) {
4274    // Boolean-valued operations are white-listed.
4275    case UO_LNot:
4276      return IntRange::forBoolType();
4277
4278    // Operations with opaque sources are black-listed.
4279    case UO_Deref:
4280    case UO_AddrOf: // should be impossible
4281      return IntRange::forValueOfType(C, E->getType());
4282
4283    default:
4284      return GetExprRange(C, UO->getSubExpr(), MaxWidth);
4285    }
4286  }
4287
4288  if (dyn_cast<OffsetOfExpr>(E)) {
4289    IntRange::forValueOfType(C, E->getType());
4290  }
4291
4292  if (FieldDecl *BitField = E->getBitField())
4293    return IntRange(BitField->getBitWidthValue(C),
4294                    BitField->getType()->isUnsignedIntegerOrEnumerationType());
4295
4296  return IntRange::forValueOfType(C, E->getType());
4297}
4298
4299static IntRange GetExprRange(ASTContext &C, Expr *E) {
4300  return GetExprRange(C, E, C.getIntWidth(E->getType()));
4301}
4302
4303/// Checks whether the given value, which currently has the given
4304/// source semantics, has the same value when coerced through the
4305/// target semantics.
4306static bool IsSameFloatAfterCast(const llvm::APFloat &value,
4307                                 const llvm::fltSemantics &Src,
4308                                 const llvm::fltSemantics &Tgt) {
4309  llvm::APFloat truncated = value;
4310
4311  bool ignored;
4312  truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored);
4313  truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored);
4314
4315  return truncated.bitwiseIsEqual(value);
4316}
4317
4318/// Checks whether the given value, which currently has the given
4319/// source semantics, has the same value when coerced through the
4320/// target semantics.
4321///
4322/// The value might be a vector of floats (or a complex number).
4323static bool IsSameFloatAfterCast(const APValue &value,
4324                                 const llvm::fltSemantics &Src,
4325                                 const llvm::fltSemantics &Tgt) {
4326  if (value.isFloat())
4327    return IsSameFloatAfterCast(value.getFloat(), Src, Tgt);
4328
4329  if (value.isVector()) {
4330    for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i)
4331      if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt))
4332        return false;
4333    return true;
4334  }
4335
4336  assert(value.isComplexFloat());
4337  return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) &&
4338          IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt));
4339}
4340
4341static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC);
4342
4343static bool IsZero(Sema &S, Expr *E) {
4344  // Suppress cases where we are comparing against an enum constant.
4345  if (const DeclRefExpr *DR =
4346      dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
4347    if (isa<EnumConstantDecl>(DR->getDecl()))
4348      return false;
4349
4350  // Suppress cases where the '0' value is expanded from a macro.
4351  if (E->getLocStart().isMacroID())
4352    return false;
4353
4354  llvm::APSInt Value;
4355  return E->isIntegerConstantExpr(Value, S.Context) && Value == 0;
4356}
4357
4358static bool HasEnumType(Expr *E) {
4359  // Strip off implicit integral promotions.
4360  while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
4361    if (ICE->getCastKind() != CK_IntegralCast &&
4362        ICE->getCastKind() != CK_NoOp)
4363      break;
4364    E = ICE->getSubExpr();
4365  }
4366
4367  return E->getType()->isEnumeralType();
4368}
4369
4370static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) {
4371  BinaryOperatorKind op = E->getOpcode();
4372  if (E->isValueDependent())
4373    return;
4374
4375  if (op == BO_LT && IsZero(S, E->getRHS())) {
4376    S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
4377      << "< 0" << "false" << HasEnumType(E->getLHS())
4378      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
4379  } else if (op == BO_GE && IsZero(S, E->getRHS())) {
4380    S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
4381      << ">= 0" << "true" << HasEnumType(E->getLHS())
4382      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
4383  } else if (op == BO_GT && IsZero(S, E->getLHS())) {
4384    S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
4385      << "0 >" << "false" << HasEnumType(E->getRHS())
4386      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
4387  } else if (op == BO_LE && IsZero(S, E->getLHS())) {
4388    S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
4389      << "0 <=" << "true" << HasEnumType(E->getRHS())
4390      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
4391  }
4392}
4393
4394static void DiagnoseOutOfRangeComparison(Sema &S, BinaryOperator *E,
4395                                         Expr *Constant, Expr *Other,
4396                                         llvm::APSInt Value,
4397                                         bool RhsConstant) {
4398  // 0 values are handled later by CheckTrivialUnsignedComparison().
4399  if (Value == 0)
4400    return;
4401
4402  BinaryOperatorKind op = E->getOpcode();
4403  QualType OtherT = Other->getType();
4404  QualType ConstantT = Constant->getType();
4405  QualType CommonT = E->getLHS()->getType();
4406  if (S.Context.hasSameUnqualifiedType(OtherT, ConstantT))
4407    return;
4408  assert((OtherT->isIntegerType() && ConstantT->isIntegerType())
4409         && "comparison with non-integer type");
4410
4411  bool ConstantSigned = ConstantT->isSignedIntegerType();
4412  bool CommonSigned = CommonT->isSignedIntegerType();
4413
4414  bool EqualityOnly = false;
4415
4416  // TODO: Investigate using GetExprRange() to get tighter bounds on
4417  // on the bit ranges.
4418  IntRange OtherRange = IntRange::forValueOfType(S.Context, OtherT);
4419  unsigned OtherWidth = OtherRange.Width;
4420
4421  if (CommonSigned) {
4422    // The common type is signed, therefore no signed to unsigned conversion.
4423    if (!OtherRange.NonNegative) {
4424      // Check that the constant is representable in type OtherT.
4425      if (ConstantSigned) {
4426        if (OtherWidth >= Value.getMinSignedBits())
4427          return;
4428      } else { // !ConstantSigned
4429        if (OtherWidth >= Value.getActiveBits() + 1)
4430          return;
4431      }
4432    } else { // !OtherSigned
4433      // Check that the constant is representable in type OtherT.
4434      // Negative values are out of range.
4435      if (ConstantSigned) {
4436        if (Value.isNonNegative() && OtherWidth >= Value.getActiveBits())
4437          return;
4438      } else { // !ConstantSigned
4439        if (OtherWidth >= Value.getActiveBits())
4440          return;
4441      }
4442    }
4443  } else {  // !CommonSigned
4444    if (OtherRange.NonNegative) {
4445      if (OtherWidth >= Value.getActiveBits())
4446        return;
4447    } else if (!OtherRange.NonNegative && !ConstantSigned) {
4448      // Check to see if the constant is representable in OtherT.
4449      if (OtherWidth > Value.getActiveBits())
4450        return;
4451      // Check to see if the constant is equivalent to a negative value
4452      // cast to CommonT.
4453      if (S.Context.getIntWidth(ConstantT) == S.Context.getIntWidth(CommonT) &&
4454          Value.isNegative() && Value.getMinSignedBits() <= OtherWidth)
4455        return;
4456      // The constant value rests between values that OtherT can represent after
4457      // conversion.  Relational comparison still works, but equality
4458      // comparisons will be tautological.
4459      EqualityOnly = true;
4460    } else { // OtherSigned && ConstantSigned
4461      assert(0 && "Two signed types converted to unsigned types.");
4462    }
4463  }
4464
4465  bool PositiveConstant = !ConstantSigned || Value.isNonNegative();
4466
4467  bool IsTrue = true;
4468  if (op == BO_EQ || op == BO_NE) {
4469    IsTrue = op == BO_NE;
4470  } else if (EqualityOnly) {
4471    return;
4472  } else if (RhsConstant) {
4473    if (op == BO_GT || op == BO_GE)
4474      IsTrue = !PositiveConstant;
4475    else // op == BO_LT || op == BO_LE
4476      IsTrue = PositiveConstant;
4477  } else {
4478    if (op == BO_LT || op == BO_LE)
4479      IsTrue = !PositiveConstant;
4480    else // op == BO_GT || op == BO_GE
4481      IsTrue = PositiveConstant;
4482  }
4483  SmallString<16> PrettySourceValue(Value.toString(10));
4484  S.Diag(E->getOperatorLoc(), diag::warn_out_of_range_compare)
4485      << PrettySourceValue << OtherT << IsTrue
4486      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
4487}
4488
4489/// Analyze the operands of the given comparison.  Implements the
4490/// fallback case from AnalyzeComparison.
4491static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) {
4492  AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
4493  AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
4494}
4495
4496/// \brief Implements -Wsign-compare.
4497///
4498/// \param E the binary operator to check for warnings
4499static void AnalyzeComparison(Sema &S, BinaryOperator *E) {
4500  // The type the comparison is being performed in.
4501  QualType T = E->getLHS()->getType();
4502  assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType())
4503         && "comparison with mismatched types");
4504  if (E->isValueDependent())
4505    return AnalyzeImpConvsInComparison(S, E);
4506
4507  Expr *LHS = E->getLHS()->IgnoreParenImpCasts();
4508  Expr *RHS = E->getRHS()->IgnoreParenImpCasts();
4509
4510  bool IsComparisonConstant = false;
4511
4512  // Check whether an integer constant comparison results in a value
4513  // of 'true' or 'false'.
4514  if (T->isIntegralType(S.Context)) {
4515    llvm::APSInt RHSValue;
4516    bool IsRHSIntegralLiteral =
4517      RHS->isIntegerConstantExpr(RHSValue, S.Context);
4518    llvm::APSInt LHSValue;
4519    bool IsLHSIntegralLiteral =
4520      LHS->isIntegerConstantExpr(LHSValue, S.Context);
4521    if (IsRHSIntegralLiteral && !IsLHSIntegralLiteral)
4522        DiagnoseOutOfRangeComparison(S, E, RHS, LHS, RHSValue, true);
4523    else if (!IsRHSIntegralLiteral && IsLHSIntegralLiteral)
4524      DiagnoseOutOfRangeComparison(S, E, LHS, RHS, LHSValue, false);
4525    else
4526      IsComparisonConstant =
4527        (IsRHSIntegralLiteral && IsLHSIntegralLiteral);
4528  } else if (!T->hasUnsignedIntegerRepresentation())
4529      IsComparisonConstant = E->isIntegerConstantExpr(S.Context);
4530
4531  // We don't do anything special if this isn't an unsigned integral
4532  // comparison:  we're only interested in integral comparisons, and
4533  // signed comparisons only happen in cases we don't care to warn about.
4534  //
4535  // We also don't care about value-dependent expressions or expressions
4536  // whose result is a constant.
4537  if (!T->hasUnsignedIntegerRepresentation() || IsComparisonConstant)
4538    return AnalyzeImpConvsInComparison(S, E);
4539
4540  // Check to see if one of the (unmodified) operands is of different
4541  // signedness.
4542  Expr *signedOperand, *unsignedOperand;
4543  if (LHS->getType()->hasSignedIntegerRepresentation()) {
4544    assert(!RHS->getType()->hasSignedIntegerRepresentation() &&
4545           "unsigned comparison between two signed integer expressions?");
4546    signedOperand = LHS;
4547    unsignedOperand = RHS;
4548  } else if (RHS->getType()->hasSignedIntegerRepresentation()) {
4549    signedOperand = RHS;
4550    unsignedOperand = LHS;
4551  } else {
4552    CheckTrivialUnsignedComparison(S, E);
4553    return AnalyzeImpConvsInComparison(S, E);
4554  }
4555
4556  // Otherwise, calculate the effective range of the signed operand.
4557  IntRange signedRange = GetExprRange(S.Context, signedOperand);
4558
4559  // Go ahead and analyze implicit conversions in the operands.  Note
4560  // that we skip the implicit conversions on both sides.
4561  AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc());
4562  AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc());
4563
4564  // If the signed range is non-negative, -Wsign-compare won't fire,
4565  // but we should still check for comparisons which are always true
4566  // or false.
4567  if (signedRange.NonNegative)
4568    return CheckTrivialUnsignedComparison(S, E);
4569
4570  // For (in)equality comparisons, if the unsigned operand is a
4571  // constant which cannot collide with a overflowed signed operand,
4572  // then reinterpreting the signed operand as unsigned will not
4573  // change the result of the comparison.
4574  if (E->isEqualityOp()) {
4575    unsigned comparisonWidth = S.Context.getIntWidth(T);
4576    IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand);
4577
4578    // We should never be unable to prove that the unsigned operand is
4579    // non-negative.
4580    assert(unsignedRange.NonNegative && "unsigned range includes negative?");
4581
4582    if (unsignedRange.Width < comparisonWidth)
4583      return;
4584  }
4585
4586  S.DiagRuntimeBehavior(E->getOperatorLoc(), E,
4587    S.PDiag(diag::warn_mixed_sign_comparison)
4588      << LHS->getType() << RHS->getType()
4589      << LHS->getSourceRange() << RHS->getSourceRange());
4590}
4591
4592/// Analyzes an attempt to assign the given value to a bitfield.
4593///
4594/// Returns true if there was something fishy about the attempt.
4595static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init,
4596                                      SourceLocation InitLoc) {
4597  assert(Bitfield->isBitField());
4598  if (Bitfield->isInvalidDecl())
4599    return false;
4600
4601  // White-list bool bitfields.
4602  if (Bitfield->getType()->isBooleanType())
4603    return false;
4604
4605  // Ignore value- or type-dependent expressions.
4606  if (Bitfield->getBitWidth()->isValueDependent() ||
4607      Bitfield->getBitWidth()->isTypeDependent() ||
4608      Init->isValueDependent() ||
4609      Init->isTypeDependent())
4610    return false;
4611
4612  Expr *OriginalInit = Init->IgnoreParenImpCasts();
4613
4614  llvm::APSInt Value;
4615  if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects))
4616    return false;
4617
4618  unsigned OriginalWidth = Value.getBitWidth();
4619  unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context);
4620
4621  if (OriginalWidth <= FieldWidth)
4622    return false;
4623
4624  // Compute the value which the bitfield will contain.
4625  llvm::APSInt TruncatedValue = Value.trunc(FieldWidth);
4626  TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType());
4627
4628  // Check whether the stored value is equal to the original value.
4629  TruncatedValue = TruncatedValue.extend(OriginalWidth);
4630  if (llvm::APSInt::isSameValue(Value, TruncatedValue))
4631    return false;
4632
4633  // Special-case bitfields of width 1: booleans are naturally 0/1, and
4634  // therefore don't strictly fit into a signed bitfield of width 1.
4635  if (FieldWidth == 1 && Value == 1)
4636    return false;
4637
4638  std::string PrettyValue = Value.toString(10);
4639  std::string PrettyTrunc = TruncatedValue.toString(10);
4640
4641  S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant)
4642    << PrettyValue << PrettyTrunc << OriginalInit->getType()
4643    << Init->getSourceRange();
4644
4645  return true;
4646}
4647
4648/// Analyze the given simple or compound assignment for warning-worthy
4649/// operations.
4650static void AnalyzeAssignment(Sema &S, BinaryOperator *E) {
4651  // Just recurse on the LHS.
4652  AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
4653
4654  // We want to recurse on the RHS as normal unless we're assigning to
4655  // a bitfield.
4656  if (FieldDecl *Bitfield = E->getLHS()->getBitField()) {
4657    if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(),
4658                                  E->getOperatorLoc())) {
4659      // Recurse, ignoring any implicit conversions on the RHS.
4660      return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(),
4661                                        E->getOperatorLoc());
4662    }
4663  }
4664
4665  AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
4666}
4667
4668/// Diagnose an implicit cast;  purely a helper for CheckImplicitConversion.
4669static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T,
4670                            SourceLocation CContext, unsigned diag,
4671                            bool pruneControlFlow = false) {
4672  if (pruneControlFlow) {
4673    S.DiagRuntimeBehavior(E->getExprLoc(), E,
4674                          S.PDiag(diag)
4675                            << SourceType << T << E->getSourceRange()
4676                            << SourceRange(CContext));
4677    return;
4678  }
4679  S.Diag(E->getExprLoc(), diag)
4680    << SourceType << T << E->getSourceRange() << SourceRange(CContext);
4681}
4682
4683/// Diagnose an implicit cast;  purely a helper for CheckImplicitConversion.
4684static void DiagnoseImpCast(Sema &S, Expr *E, QualType T,
4685                            SourceLocation CContext, unsigned diag,
4686                            bool pruneControlFlow = false) {
4687  DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow);
4688}
4689
4690/// Diagnose an implicit cast from a literal expression. Does not warn when the
4691/// cast wouldn't lose information.
4692void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T,
4693                                    SourceLocation CContext) {
4694  // Try to convert the literal exactly to an integer. If we can, don't warn.
4695  bool isExact = false;
4696  const llvm::APFloat &Value = FL->getValue();
4697  llvm::APSInt IntegerValue(S.Context.getIntWidth(T),
4698                            T->hasUnsignedIntegerRepresentation());
4699  if (Value.convertToInteger(IntegerValue,
4700                             llvm::APFloat::rmTowardZero, &isExact)
4701      == llvm::APFloat::opOK && isExact)
4702    return;
4703
4704  SmallString<16> PrettySourceValue;
4705  Value.toString(PrettySourceValue);
4706  SmallString<16> PrettyTargetValue;
4707  if (T->isSpecificBuiltinType(BuiltinType::Bool))
4708    PrettyTargetValue = IntegerValue == 0 ? "false" : "true";
4709  else
4710    IntegerValue.toString(PrettyTargetValue);
4711
4712  S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer)
4713    << FL->getType() << T.getUnqualifiedType() << PrettySourceValue
4714    << PrettyTargetValue << FL->getSourceRange() << SourceRange(CContext);
4715}
4716
4717std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) {
4718  if (!Range.Width) return "0";
4719
4720  llvm::APSInt ValueInRange = Value;
4721  ValueInRange.setIsSigned(!Range.NonNegative);
4722  ValueInRange = ValueInRange.trunc(Range.Width);
4723  return ValueInRange.toString(10);
4724}
4725
4726static bool IsImplicitBoolFloatConversion(Sema &S, Expr *Ex, bool ToBool) {
4727  if (!isa<ImplicitCastExpr>(Ex))
4728    return false;
4729
4730  Expr *InnerE = Ex->IgnoreParenImpCasts();
4731  const Type *Target = S.Context.getCanonicalType(Ex->getType()).getTypePtr();
4732  const Type *Source =
4733    S.Context.getCanonicalType(InnerE->getType()).getTypePtr();
4734  if (Target->isDependentType())
4735    return false;
4736
4737  const BuiltinType *FloatCandidateBT =
4738    dyn_cast<BuiltinType>(ToBool ? Source : Target);
4739  const Type *BoolCandidateType = ToBool ? Target : Source;
4740
4741  return (BoolCandidateType->isSpecificBuiltinType(BuiltinType::Bool) &&
4742          FloatCandidateBT && (FloatCandidateBT->isFloatingPoint()));
4743}
4744
4745void CheckImplicitArgumentConversions(Sema &S, CallExpr *TheCall,
4746                                      SourceLocation CC) {
4747  unsigned NumArgs = TheCall->getNumArgs();
4748  for (unsigned i = 0; i < NumArgs; ++i) {
4749    Expr *CurrA = TheCall->getArg(i);
4750    if (!IsImplicitBoolFloatConversion(S, CurrA, true))
4751      continue;
4752
4753    bool IsSwapped = ((i > 0) &&
4754        IsImplicitBoolFloatConversion(S, TheCall->getArg(i - 1), false));
4755    IsSwapped |= ((i < (NumArgs - 1)) &&
4756        IsImplicitBoolFloatConversion(S, TheCall->getArg(i + 1), false));
4757    if (IsSwapped) {
4758      // Warn on this floating-point to bool conversion.
4759      DiagnoseImpCast(S, CurrA->IgnoreParenImpCasts(),
4760                      CurrA->getType(), CC,
4761                      diag::warn_impcast_floating_point_to_bool);
4762    }
4763  }
4764}
4765
4766void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
4767                             SourceLocation CC, bool *ICContext = 0) {
4768  if (E->isTypeDependent() || E->isValueDependent()) return;
4769
4770  const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr();
4771  const Type *Target = S.Context.getCanonicalType(T).getTypePtr();
4772  if (Source == Target) return;
4773  if (Target->isDependentType()) return;
4774
4775  // If the conversion context location is invalid don't complain. We also
4776  // don't want to emit a warning if the issue occurs from the expansion of
4777  // a system macro. The problem is that 'getSpellingLoc()' is slow, so we
4778  // delay this check as long as possible. Once we detect we are in that
4779  // scenario, we just return.
4780  if (CC.isInvalid())
4781    return;
4782
4783  // Diagnose implicit casts to bool.
4784  if (Target->isSpecificBuiltinType(BuiltinType::Bool)) {
4785    if (isa<StringLiteral>(E))
4786      // Warn on string literal to bool.  Checks for string literals in logical
4787      // expressions, for instances, assert(0 && "error here"), is prevented
4788      // by a check in AnalyzeImplicitConversions().
4789      return DiagnoseImpCast(S, E, T, CC,
4790                             diag::warn_impcast_string_literal_to_bool);
4791    if (Source->isFunctionType()) {
4792      // Warn on function to bool. Checks free functions and static member
4793      // functions. Weakly imported functions are excluded from the check,
4794      // since it's common to test their value to check whether the linker
4795      // found a definition for them.
4796      ValueDecl *D = 0;
4797      if (DeclRefExpr* R = dyn_cast<DeclRefExpr>(E)) {
4798        D = R->getDecl();
4799      } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) {
4800        D = M->getMemberDecl();
4801      }
4802
4803      if (D && !D->isWeak()) {
4804        if (FunctionDecl* F = dyn_cast<FunctionDecl>(D)) {
4805          S.Diag(E->getExprLoc(), diag::warn_impcast_function_to_bool)
4806            << F << E->getSourceRange() << SourceRange(CC);
4807          S.Diag(E->getExprLoc(), diag::note_function_to_bool_silence)
4808            << FixItHint::CreateInsertion(E->getExprLoc(), "&");
4809          QualType ReturnType;
4810          UnresolvedSet<4> NonTemplateOverloads;
4811          S.isExprCallable(*E, ReturnType, NonTemplateOverloads);
4812          if (!ReturnType.isNull()
4813              && ReturnType->isSpecificBuiltinType(BuiltinType::Bool))
4814            S.Diag(E->getExprLoc(), diag::note_function_to_bool_call)
4815              << FixItHint::CreateInsertion(
4816                 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()), "()");
4817          return;
4818        }
4819      }
4820    }
4821  }
4822
4823  // Strip vector types.
4824  if (isa<VectorType>(Source)) {
4825    if (!isa<VectorType>(Target)) {
4826      if (S.SourceMgr.isInSystemMacro(CC))
4827        return;
4828      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar);
4829    }
4830
4831    // If the vector cast is cast between two vectors of the same size, it is
4832    // a bitcast, not a conversion.
4833    if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target))
4834      return;
4835
4836    Source = cast<VectorType>(Source)->getElementType().getTypePtr();
4837    Target = cast<VectorType>(Target)->getElementType().getTypePtr();
4838  }
4839
4840  // Strip complex types.
4841  if (isa<ComplexType>(Source)) {
4842    if (!isa<ComplexType>(Target)) {
4843      if (S.SourceMgr.isInSystemMacro(CC))
4844        return;
4845
4846      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar);
4847    }
4848
4849    Source = cast<ComplexType>(Source)->getElementType().getTypePtr();
4850    Target = cast<ComplexType>(Target)->getElementType().getTypePtr();
4851  }
4852
4853  const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source);
4854  const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target);
4855
4856  // If the source is floating point...
4857  if (SourceBT && SourceBT->isFloatingPoint()) {
4858    // ...and the target is floating point...
4859    if (TargetBT && TargetBT->isFloatingPoint()) {
4860      // ...then warn if we're dropping FP rank.
4861
4862      // Builtin FP kinds are ordered by increasing FP rank.
4863      if (SourceBT->getKind() > TargetBT->getKind()) {
4864        // Don't warn about float constants that are precisely
4865        // representable in the target type.
4866        Expr::EvalResult result;
4867        if (E->EvaluateAsRValue(result, S.Context)) {
4868          // Value might be a float, a float vector, or a float complex.
4869          if (IsSameFloatAfterCast(result.Val,
4870                   S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)),
4871                   S.Context.getFloatTypeSemantics(QualType(SourceBT, 0))))
4872            return;
4873        }
4874
4875        if (S.SourceMgr.isInSystemMacro(CC))
4876          return;
4877
4878        DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision);
4879      }
4880      return;
4881    }
4882
4883    // If the target is integral, always warn.
4884    if (TargetBT && TargetBT->isInteger()) {
4885      if (S.SourceMgr.isInSystemMacro(CC))
4886        return;
4887
4888      Expr *InnerE = E->IgnoreParenImpCasts();
4889      // We also want to warn on, e.g., "int i = -1.234"
4890      if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE))
4891        if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus)
4892          InnerE = UOp->getSubExpr()->IgnoreParenImpCasts();
4893
4894      if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) {
4895        DiagnoseFloatingLiteralImpCast(S, FL, T, CC);
4896      } else {
4897        DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer);
4898      }
4899    }
4900
4901    // If the target is bool, warn if expr is a function or method call.
4902    if (Target->isSpecificBuiltinType(BuiltinType::Bool) &&
4903        isa<CallExpr>(E)) {
4904      // Check last argument of function call to see if it is an
4905      // implicit cast from a type matching the type the result
4906      // is being cast to.
4907      CallExpr *CEx = cast<CallExpr>(E);
4908      unsigned NumArgs = CEx->getNumArgs();
4909      if (NumArgs > 0) {
4910        Expr *LastA = CEx->getArg(NumArgs - 1);
4911        Expr *InnerE = LastA->IgnoreParenImpCasts();
4912        const Type *InnerType =
4913          S.Context.getCanonicalType(InnerE->getType()).getTypePtr();
4914        if (isa<ImplicitCastExpr>(LastA) && (InnerType == Target)) {
4915          // Warn on this floating-point to bool conversion
4916          DiagnoseImpCast(S, E, T, CC,
4917                          diag::warn_impcast_floating_point_to_bool);
4918        }
4919      }
4920    }
4921    return;
4922  }
4923
4924  if ((E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull)
4925           == Expr::NPCK_GNUNull) && !Target->isAnyPointerType()
4926      && !Target->isBlockPointerType() && !Target->isMemberPointerType()
4927      && Target->isScalarType()) {
4928    SourceLocation Loc = E->getSourceRange().getBegin();
4929    if (Loc.isMacroID())
4930      Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first;
4931    if (!Loc.isMacroID() || CC.isMacroID())
4932      S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer)
4933          << T << clang::SourceRange(CC)
4934          << FixItHint::CreateReplacement(Loc, S.getFixItZeroLiteralForType(T));
4935  }
4936
4937  if (!Source->isIntegerType() || !Target->isIntegerType())
4938    return;
4939
4940  // TODO: remove this early return once the false positives for constant->bool
4941  // in templates, macros, etc, are reduced or removed.
4942  if (Target->isSpecificBuiltinType(BuiltinType::Bool))
4943    return;
4944
4945  IntRange SourceRange = GetExprRange(S.Context, E);
4946  IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target);
4947
4948  if (SourceRange.Width > TargetRange.Width) {
4949    // If the source is a constant, use a default-on diagnostic.
4950    // TODO: this should happen for bitfield stores, too.
4951    llvm::APSInt Value(32);
4952    if (E->isIntegerConstantExpr(Value, S.Context)) {
4953      if (S.SourceMgr.isInSystemMacro(CC))
4954        return;
4955
4956      std::string PrettySourceValue = Value.toString(10);
4957      std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange);
4958
4959      S.DiagRuntimeBehavior(E->getExprLoc(), E,
4960        S.PDiag(diag::warn_impcast_integer_precision_constant)
4961            << PrettySourceValue << PrettyTargetValue
4962            << E->getType() << T << E->getSourceRange()
4963            << clang::SourceRange(CC));
4964      return;
4965    }
4966
4967    // People want to build with -Wshorten-64-to-32 and not -Wconversion.
4968    if (S.SourceMgr.isInSystemMacro(CC))
4969      return;
4970
4971    if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64)
4972      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32,
4973                             /* pruneControlFlow */ true);
4974    return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision);
4975  }
4976
4977  if ((TargetRange.NonNegative && !SourceRange.NonNegative) ||
4978      (!TargetRange.NonNegative && SourceRange.NonNegative &&
4979       SourceRange.Width == TargetRange.Width)) {
4980
4981    if (S.SourceMgr.isInSystemMacro(CC))
4982      return;
4983
4984    unsigned DiagID = diag::warn_impcast_integer_sign;
4985
4986    // Traditionally, gcc has warned about this under -Wsign-compare.
4987    // We also want to warn about it in -Wconversion.
4988    // So if -Wconversion is off, use a completely identical diagnostic
4989    // in the sign-compare group.
4990    // The conditional-checking code will
4991    if (ICContext) {
4992      DiagID = diag::warn_impcast_integer_sign_conditional;
4993      *ICContext = true;
4994    }
4995
4996    return DiagnoseImpCast(S, E, T, CC, DiagID);
4997  }
4998
4999  // Diagnose conversions between different enumeration types.
5000  // In C, we pretend that the type of an EnumConstantDecl is its enumeration
5001  // type, to give us better diagnostics.
5002  QualType SourceType = E->getType();
5003  if (!S.getLangOpts().CPlusPlus) {
5004    if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
5005      if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) {
5006        EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext());
5007        SourceType = S.Context.getTypeDeclType(Enum);
5008        Source = S.Context.getCanonicalType(SourceType).getTypePtr();
5009      }
5010  }
5011
5012  if (const EnumType *SourceEnum = Source->getAs<EnumType>())
5013    if (const EnumType *TargetEnum = Target->getAs<EnumType>())
5014      if ((SourceEnum->getDecl()->getIdentifier() ||
5015           SourceEnum->getDecl()->getTypedefNameForAnonDecl()) &&
5016          (TargetEnum->getDecl()->getIdentifier() ||
5017           TargetEnum->getDecl()->getTypedefNameForAnonDecl()) &&
5018          SourceEnum != TargetEnum) {
5019        if (S.SourceMgr.isInSystemMacro(CC))
5020          return;
5021
5022        return DiagnoseImpCast(S, E, SourceType, T, CC,
5023                               diag::warn_impcast_different_enum_types);
5024      }
5025
5026  return;
5027}
5028
5029void CheckConditionalOperator(Sema &S, ConditionalOperator *E,
5030                              SourceLocation CC, QualType T);
5031
5032void CheckConditionalOperand(Sema &S, Expr *E, QualType T,
5033                             SourceLocation CC, bool &ICContext) {
5034  E = E->IgnoreParenImpCasts();
5035
5036  if (isa<ConditionalOperator>(E))
5037    return CheckConditionalOperator(S, cast<ConditionalOperator>(E), CC, T);
5038
5039  AnalyzeImplicitConversions(S, E, CC);
5040  if (E->getType() != T)
5041    return CheckImplicitConversion(S, E, T, CC, &ICContext);
5042  return;
5043}
5044
5045void CheckConditionalOperator(Sema &S, ConditionalOperator *E,
5046                              SourceLocation CC, QualType T) {
5047  AnalyzeImplicitConversions(S, E->getCond(), CC);
5048
5049  bool Suspicious = false;
5050  CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious);
5051  CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious);
5052
5053  // If -Wconversion would have warned about either of the candidates
5054  // for a signedness conversion to the context type...
5055  if (!Suspicious) return;
5056
5057  // ...but it's currently ignored...
5058  if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional,
5059                                 CC))
5060    return;
5061
5062  // ...then check whether it would have warned about either of the
5063  // candidates for a signedness conversion to the condition type.
5064  if (E->getType() == T) return;
5065
5066  Suspicious = false;
5067  CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(),
5068                          E->getType(), CC, &Suspicious);
5069  if (!Suspicious)
5070    CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(),
5071                            E->getType(), CC, &Suspicious);
5072}
5073
5074/// AnalyzeImplicitConversions - Find and report any interesting
5075/// implicit conversions in the given expression.  There are a couple
5076/// of competing diagnostics here, -Wconversion and -Wsign-compare.
5077void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) {
5078  QualType T = OrigE->getType();
5079  Expr *E = OrigE->IgnoreParenImpCasts();
5080
5081  if (E->isTypeDependent() || E->isValueDependent())
5082    return;
5083
5084  // For conditional operators, we analyze the arguments as if they
5085  // were being fed directly into the output.
5086  if (isa<ConditionalOperator>(E)) {
5087    ConditionalOperator *CO = cast<ConditionalOperator>(E);
5088    CheckConditionalOperator(S, CO, CC, T);
5089    return;
5090  }
5091
5092  // Check implicit argument conversions for function calls.
5093  if (CallExpr *Call = dyn_cast<CallExpr>(E))
5094    CheckImplicitArgumentConversions(S, Call, CC);
5095
5096  // Go ahead and check any implicit conversions we might have skipped.
5097  // The non-canonical typecheck is just an optimization;
5098  // CheckImplicitConversion will filter out dead implicit conversions.
5099  if (E->getType() != T)
5100    CheckImplicitConversion(S, E, T, CC);
5101
5102  // Now continue drilling into this expression.
5103
5104  // Skip past explicit casts.
5105  if (isa<ExplicitCastExpr>(E)) {
5106    E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts();
5107    return AnalyzeImplicitConversions(S, E, CC);
5108  }
5109
5110  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
5111    // Do a somewhat different check with comparison operators.
5112    if (BO->isComparisonOp())
5113      return AnalyzeComparison(S, BO);
5114
5115    // And with simple assignments.
5116    if (BO->getOpcode() == BO_Assign)
5117      return AnalyzeAssignment(S, BO);
5118  }
5119
5120  // These break the otherwise-useful invariant below.  Fortunately,
5121  // we don't really need to recurse into them, because any internal
5122  // expressions should have been analyzed already when they were
5123  // built into statements.
5124  if (isa<StmtExpr>(E)) return;
5125
5126  // Don't descend into unevaluated contexts.
5127  if (isa<UnaryExprOrTypeTraitExpr>(E)) return;
5128
5129  // Now just recurse over the expression's children.
5130  CC = E->getExprLoc();
5131  BinaryOperator *BO = dyn_cast<BinaryOperator>(E);
5132  bool IsLogicalOperator = BO && BO->isLogicalOp();
5133  for (Stmt::child_range I = E->children(); I; ++I) {
5134    Expr *ChildExpr = dyn_cast_or_null<Expr>(*I);
5135    if (!ChildExpr)
5136      continue;
5137
5138    if (IsLogicalOperator &&
5139        isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts()))
5140      // Ignore checking string literals that are in logical operators.
5141      continue;
5142    AnalyzeImplicitConversions(S, ChildExpr, CC);
5143  }
5144}
5145
5146} // end anonymous namespace
5147
5148/// Diagnoses "dangerous" implicit conversions within the given
5149/// expression (which is a full expression).  Implements -Wconversion
5150/// and -Wsign-compare.
5151///
5152/// \param CC the "context" location of the implicit conversion, i.e.
5153///   the most location of the syntactic entity requiring the implicit
5154///   conversion
5155void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) {
5156  // Don't diagnose in unevaluated contexts.
5157  if (isUnevaluatedContext())
5158    return;
5159
5160  // Don't diagnose for value- or type-dependent expressions.
5161  if (E->isTypeDependent() || E->isValueDependent())
5162    return;
5163
5164  // Check for array bounds violations in cases where the check isn't triggered
5165  // elsewhere for other Expr types (like BinaryOperators), e.g. when an
5166  // ArraySubscriptExpr is on the RHS of a variable initialization.
5167  CheckArrayAccess(E);
5168
5169  // This is not the right CC for (e.g.) a variable initialization.
5170  AnalyzeImplicitConversions(*this, E, CC);
5171}
5172
5173void Sema::CheckBitFieldInitialization(SourceLocation InitLoc,
5174                                       FieldDecl *BitField,
5175                                       Expr *Init) {
5176  (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc);
5177}
5178
5179/// CheckParmsForFunctionDef - Check that the parameters of the given
5180/// function are appropriate for the definition of a function. This
5181/// takes care of any checks that cannot be performed on the
5182/// declaration itself, e.g., that the types of each of the function
5183/// parameters are complete.
5184bool Sema::CheckParmsForFunctionDef(ParmVarDecl **P, ParmVarDecl **PEnd,
5185                                    bool CheckParameterNames) {
5186  bool HasInvalidParm = false;
5187  for (; P != PEnd; ++P) {
5188    ParmVarDecl *Param = *P;
5189
5190    // C99 6.7.5.3p4: the parameters in a parameter type list in a
5191    // function declarator that is part of a function definition of
5192    // that function shall not have incomplete type.
5193    //
5194    // This is also C++ [dcl.fct]p6.
5195    if (!Param->isInvalidDecl() &&
5196        RequireCompleteType(Param->getLocation(), Param->getType(),
5197                            diag::err_typecheck_decl_incomplete_type)) {
5198      Param->setInvalidDecl();
5199      HasInvalidParm = true;
5200    }
5201
5202    // C99 6.9.1p5: If the declarator includes a parameter type list, the
5203    // declaration of each parameter shall include an identifier.
5204    if (CheckParameterNames &&
5205        Param->getIdentifier() == 0 &&
5206        !Param->isImplicit() &&
5207        !getLangOpts().CPlusPlus)
5208      Diag(Param->getLocation(), diag::err_parameter_name_omitted);
5209
5210    // C99 6.7.5.3p12:
5211    //   If the function declarator is not part of a definition of that
5212    //   function, parameters may have incomplete type and may use the [*]
5213    //   notation in their sequences of declarator specifiers to specify
5214    //   variable length array types.
5215    QualType PType = Param->getOriginalType();
5216    if (const ArrayType *AT = Context.getAsArrayType(PType)) {
5217      if (AT->getSizeModifier() == ArrayType::Star) {
5218        // FIXME: This diagnosic should point the '[*]' if source-location
5219        // information is added for it.
5220        Diag(Param->getLocation(), diag::err_array_star_in_function_definition);
5221      }
5222    }
5223  }
5224
5225  return HasInvalidParm;
5226}
5227
5228/// CheckCastAlign - Implements -Wcast-align, which warns when a
5229/// pointer cast increases the alignment requirements.
5230void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) {
5231  // This is actually a lot of work to potentially be doing on every
5232  // cast; don't do it if we're ignoring -Wcast_align (as is the default).
5233  if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align,
5234                                          TRange.getBegin())
5235        == DiagnosticsEngine::Ignored)
5236    return;
5237
5238  // Ignore dependent types.
5239  if (T->isDependentType() || Op->getType()->isDependentType())
5240    return;
5241
5242  // Require that the destination be a pointer type.
5243  const PointerType *DestPtr = T->getAs<PointerType>();
5244  if (!DestPtr) return;
5245
5246  // If the destination has alignment 1, we're done.
5247  QualType DestPointee = DestPtr->getPointeeType();
5248  if (DestPointee->isIncompleteType()) return;
5249  CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee);
5250  if (DestAlign.isOne()) return;
5251
5252  // Require that the source be a pointer type.
5253  const PointerType *SrcPtr = Op->getType()->getAs<PointerType>();
5254  if (!SrcPtr) return;
5255  QualType SrcPointee = SrcPtr->getPointeeType();
5256
5257  // Whitelist casts from cv void*.  We already implicitly
5258  // whitelisted casts to cv void*, since they have alignment 1.
5259  // Also whitelist casts involving incomplete types, which implicitly
5260  // includes 'void'.
5261  if (SrcPointee->isIncompleteType()) return;
5262
5263  CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee);
5264  if (SrcAlign >= DestAlign) return;
5265
5266  Diag(TRange.getBegin(), diag::warn_cast_align)
5267    << Op->getType() << T
5268    << static_cast<unsigned>(SrcAlign.getQuantity())
5269    << static_cast<unsigned>(DestAlign.getQuantity())
5270    << TRange << Op->getSourceRange();
5271}
5272
5273static const Type* getElementType(const Expr *BaseExpr) {
5274  const Type* EltType = BaseExpr->getType().getTypePtr();
5275  if (EltType->isAnyPointerType())
5276    return EltType->getPointeeType().getTypePtr();
5277  else if (EltType->isArrayType())
5278    return EltType->getBaseElementTypeUnsafe();
5279  return EltType;
5280}
5281
5282/// \brief Check whether this array fits the idiom of a size-one tail padded
5283/// array member of a struct.
5284///
5285/// We avoid emitting out-of-bounds access warnings for such arrays as they are
5286/// commonly used to emulate flexible arrays in C89 code.
5287static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size,
5288                                    const NamedDecl *ND) {
5289  if (Size != 1 || !ND) return false;
5290
5291  const FieldDecl *FD = dyn_cast<FieldDecl>(ND);
5292  if (!FD) return false;
5293
5294  // Don't consider sizes resulting from macro expansions or template argument
5295  // substitution to form C89 tail-padded arrays.
5296
5297  TypeSourceInfo *TInfo = FD->getTypeSourceInfo();
5298  while (TInfo) {
5299    TypeLoc TL = TInfo->getTypeLoc();
5300    // Look through typedefs.
5301    const TypedefTypeLoc *TTL = dyn_cast<TypedefTypeLoc>(&TL);
5302    if (TTL) {
5303      const TypedefNameDecl *TDL = TTL->getTypedefNameDecl();
5304      TInfo = TDL->getTypeSourceInfo();
5305      continue;
5306    }
5307    ConstantArrayTypeLoc CTL = cast<ConstantArrayTypeLoc>(TL);
5308    const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr());
5309    if (!SizeExpr || SizeExpr->getExprLoc().isMacroID())
5310      return false;
5311    break;
5312  }
5313
5314  const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext());
5315  if (!RD) return false;
5316  if (RD->isUnion()) return false;
5317  if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
5318    if (!CRD->isStandardLayout()) return false;
5319  }
5320
5321  // See if this is the last field decl in the record.
5322  const Decl *D = FD;
5323  while ((D = D->getNextDeclInContext()))
5324    if (isa<FieldDecl>(D))
5325      return false;
5326  return true;
5327}
5328
5329void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr,
5330                            const ArraySubscriptExpr *ASE,
5331                            bool AllowOnePastEnd, bool IndexNegated) {
5332  IndexExpr = IndexExpr->IgnoreParenImpCasts();
5333  if (IndexExpr->isValueDependent())
5334    return;
5335
5336  const Type *EffectiveType = getElementType(BaseExpr);
5337  BaseExpr = BaseExpr->IgnoreParenCasts();
5338  const ConstantArrayType *ArrayTy =
5339    Context.getAsConstantArrayType(BaseExpr->getType());
5340  if (!ArrayTy)
5341    return;
5342
5343  llvm::APSInt index;
5344  if (!IndexExpr->EvaluateAsInt(index, Context))
5345    return;
5346  if (IndexNegated)
5347    index = -index;
5348
5349  const NamedDecl *ND = NULL;
5350  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))
5351    ND = dyn_cast<NamedDecl>(DRE->getDecl());
5352  if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr))
5353    ND = dyn_cast<NamedDecl>(ME->getMemberDecl());
5354
5355  if (index.isUnsigned() || !index.isNegative()) {
5356    llvm::APInt size = ArrayTy->getSize();
5357    if (!size.isStrictlyPositive())
5358      return;
5359
5360    const Type* BaseType = getElementType(BaseExpr);
5361    if (BaseType != EffectiveType) {
5362      // Make sure we're comparing apples to apples when comparing index to size
5363      uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType);
5364      uint64_t array_typesize = Context.getTypeSize(BaseType);
5365      // Handle ptrarith_typesize being zero, such as when casting to void*
5366      if (!ptrarith_typesize) ptrarith_typesize = 1;
5367      if (ptrarith_typesize != array_typesize) {
5368        // There's a cast to a different size type involved
5369        uint64_t ratio = array_typesize / ptrarith_typesize;
5370        // TODO: Be smarter about handling cases where array_typesize is not a
5371        // multiple of ptrarith_typesize
5372        if (ptrarith_typesize * ratio == array_typesize)
5373          size *= llvm::APInt(size.getBitWidth(), ratio);
5374      }
5375    }
5376
5377    if (size.getBitWidth() > index.getBitWidth())
5378      index = index.zext(size.getBitWidth());
5379    else if (size.getBitWidth() < index.getBitWidth())
5380      size = size.zext(index.getBitWidth());
5381
5382    // For array subscripting the index must be less than size, but for pointer
5383    // arithmetic also allow the index (offset) to be equal to size since
5384    // computing the next address after the end of the array is legal and
5385    // commonly done e.g. in C++ iterators and range-based for loops.
5386    if (AllowOnePastEnd ? index.ule(size) : index.ult(size))
5387      return;
5388
5389    // Also don't warn for arrays of size 1 which are members of some
5390    // structure. These are often used to approximate flexible arrays in C89
5391    // code.
5392    if (IsTailPaddedMemberArray(*this, size, ND))
5393      return;
5394
5395    // Suppress the warning if the subscript expression (as identified by the
5396    // ']' location) and the index expression are both from macro expansions
5397    // within a system header.
5398    if (ASE) {
5399      SourceLocation RBracketLoc = SourceMgr.getSpellingLoc(
5400          ASE->getRBracketLoc());
5401      if (SourceMgr.isInSystemHeader(RBracketLoc)) {
5402        SourceLocation IndexLoc = SourceMgr.getSpellingLoc(
5403            IndexExpr->getLocStart());
5404        if (SourceMgr.isFromSameFile(RBracketLoc, IndexLoc))
5405          return;
5406      }
5407    }
5408
5409    unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds;
5410    if (ASE)
5411      DiagID = diag::warn_array_index_exceeds_bounds;
5412
5413    DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr,
5414                        PDiag(DiagID) << index.toString(10, true)
5415                          << size.toString(10, true)
5416                          << (unsigned)size.getLimitedValue(~0U)
5417                          << IndexExpr->getSourceRange());
5418  } else {
5419    unsigned DiagID = diag::warn_array_index_precedes_bounds;
5420    if (!ASE) {
5421      DiagID = diag::warn_ptr_arith_precedes_bounds;
5422      if (index.isNegative()) index = -index;
5423    }
5424
5425    DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr,
5426                        PDiag(DiagID) << index.toString(10, true)
5427                          << IndexExpr->getSourceRange());
5428  }
5429
5430  if (!ND) {
5431    // Try harder to find a NamedDecl to point at in the note.
5432    while (const ArraySubscriptExpr *ASE =
5433           dyn_cast<ArraySubscriptExpr>(BaseExpr))
5434      BaseExpr = ASE->getBase()->IgnoreParenCasts();
5435    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))
5436      ND = dyn_cast<NamedDecl>(DRE->getDecl());
5437    if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr))
5438      ND = dyn_cast<NamedDecl>(ME->getMemberDecl());
5439  }
5440
5441  if (ND)
5442    DiagRuntimeBehavior(ND->getLocStart(), BaseExpr,
5443                        PDiag(diag::note_array_index_out_of_bounds)
5444                          << ND->getDeclName());
5445}
5446
5447void Sema::CheckArrayAccess(const Expr *expr) {
5448  int AllowOnePastEnd = 0;
5449  while (expr) {
5450    expr = expr->IgnoreParenImpCasts();
5451    switch (expr->getStmtClass()) {
5452      case Stmt::ArraySubscriptExprClass: {
5453        const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr);
5454        CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE,
5455                         AllowOnePastEnd > 0);
5456        return;
5457      }
5458      case Stmt::UnaryOperatorClass: {
5459        // Only unwrap the * and & unary operators
5460        const UnaryOperator *UO = cast<UnaryOperator>(expr);
5461        expr = UO->getSubExpr();
5462        switch (UO->getOpcode()) {
5463          case UO_AddrOf:
5464            AllowOnePastEnd++;
5465            break;
5466          case UO_Deref:
5467            AllowOnePastEnd--;
5468            break;
5469          default:
5470            return;
5471        }
5472        break;
5473      }
5474      case Stmt::ConditionalOperatorClass: {
5475        const ConditionalOperator *cond = cast<ConditionalOperator>(expr);
5476        if (const Expr *lhs = cond->getLHS())
5477          CheckArrayAccess(lhs);
5478        if (const Expr *rhs = cond->getRHS())
5479          CheckArrayAccess(rhs);
5480        return;
5481      }
5482      default:
5483        return;
5484    }
5485  }
5486}
5487
5488//===--- CHECK: Objective-C retain cycles ----------------------------------//
5489
5490namespace {
5491  struct RetainCycleOwner {
5492    RetainCycleOwner() : Variable(0), Indirect(false) {}
5493    VarDecl *Variable;
5494    SourceRange Range;
5495    SourceLocation Loc;
5496    bool Indirect;
5497
5498    void setLocsFrom(Expr *e) {
5499      Loc = e->getExprLoc();
5500      Range = e->getSourceRange();
5501    }
5502  };
5503}
5504
5505/// Consider whether capturing the given variable can possibly lead to
5506/// a retain cycle.
5507static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) {
5508  // In ARC, it's captured strongly iff the variable has __strong
5509  // lifetime.  In MRR, it's captured strongly if the variable is
5510  // __block and has an appropriate type.
5511  if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
5512    return false;
5513
5514  owner.Variable = var;
5515  if (ref)
5516    owner.setLocsFrom(ref);
5517  return true;
5518}
5519
5520static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) {
5521  while (true) {
5522    e = e->IgnoreParens();
5523    if (CastExpr *cast = dyn_cast<CastExpr>(e)) {
5524      switch (cast->getCastKind()) {
5525      case CK_BitCast:
5526      case CK_LValueBitCast:
5527      case CK_LValueToRValue:
5528      case CK_ARCReclaimReturnedObject:
5529        e = cast->getSubExpr();
5530        continue;
5531
5532      default:
5533        return false;
5534      }
5535    }
5536
5537    if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) {
5538      ObjCIvarDecl *ivar = ref->getDecl();
5539      if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
5540        return false;
5541
5542      // Try to find a retain cycle in the base.
5543      if (!findRetainCycleOwner(S, ref->getBase(), owner))
5544        return false;
5545
5546      if (ref->isFreeIvar()) owner.setLocsFrom(ref);
5547      owner.Indirect = true;
5548      return true;
5549    }
5550
5551    if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) {
5552      VarDecl *var = dyn_cast<VarDecl>(ref->getDecl());
5553      if (!var) return false;
5554      return considerVariable(var, ref, owner);
5555    }
5556
5557    if (MemberExpr *member = dyn_cast<MemberExpr>(e)) {
5558      if (member->isArrow()) return false;
5559
5560      // Don't count this as an indirect ownership.
5561      e = member->getBase();
5562      continue;
5563    }
5564
5565    if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) {
5566      // Only pay attention to pseudo-objects on property references.
5567      ObjCPropertyRefExpr *pre
5568        = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm()
5569                                              ->IgnoreParens());
5570      if (!pre) return false;
5571      if (pre->isImplicitProperty()) return false;
5572      ObjCPropertyDecl *property = pre->getExplicitProperty();
5573      if (!property->isRetaining() &&
5574          !(property->getPropertyIvarDecl() &&
5575            property->getPropertyIvarDecl()->getType()
5576              .getObjCLifetime() == Qualifiers::OCL_Strong))
5577          return false;
5578
5579      owner.Indirect = true;
5580      if (pre->isSuperReceiver()) {
5581        owner.Variable = S.getCurMethodDecl()->getSelfDecl();
5582        if (!owner.Variable)
5583          return false;
5584        owner.Loc = pre->getLocation();
5585        owner.Range = pre->getSourceRange();
5586        return true;
5587      }
5588      e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase())
5589                              ->getSourceExpr());
5590      continue;
5591    }
5592
5593    // Array ivars?
5594
5595    return false;
5596  }
5597}
5598
5599namespace {
5600  struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> {
5601    FindCaptureVisitor(ASTContext &Context, VarDecl *variable)
5602      : EvaluatedExprVisitor<FindCaptureVisitor>(Context),
5603        Variable(variable), Capturer(0) {}
5604
5605    VarDecl *Variable;
5606    Expr *Capturer;
5607
5608    void VisitDeclRefExpr(DeclRefExpr *ref) {
5609      if (ref->getDecl() == Variable && !Capturer)
5610        Capturer = ref;
5611    }
5612
5613    void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) {
5614      if (Capturer) return;
5615      Visit(ref->getBase());
5616      if (Capturer && ref->isFreeIvar())
5617        Capturer = ref;
5618    }
5619
5620    void VisitBlockExpr(BlockExpr *block) {
5621      // Look inside nested blocks
5622      if (block->getBlockDecl()->capturesVariable(Variable))
5623        Visit(block->getBlockDecl()->getBody());
5624    }
5625
5626    void VisitOpaqueValueExpr(OpaqueValueExpr *OVE) {
5627      if (Capturer) return;
5628      if (OVE->getSourceExpr())
5629        Visit(OVE->getSourceExpr());
5630    }
5631  };
5632}
5633
5634/// Check whether the given argument is a block which captures a
5635/// variable.
5636static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) {
5637  assert(owner.Variable && owner.Loc.isValid());
5638
5639  e = e->IgnoreParenCasts();
5640
5641  // Look through [^{...} copy] and Block_copy(^{...}).
5642  if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(e)) {
5643    Selector Cmd = ME->getSelector();
5644    if (Cmd.isUnarySelector() && Cmd.getNameForSlot(0) == "copy") {
5645      e = ME->getInstanceReceiver();
5646      if (!e)
5647        return 0;
5648      e = e->IgnoreParenCasts();
5649    }
5650  } else if (CallExpr *CE = dyn_cast<CallExpr>(e)) {
5651    if (CE->getNumArgs() == 1) {
5652      FunctionDecl *Fn = dyn_cast_or_null<FunctionDecl>(CE->getCalleeDecl());
5653      if (Fn) {
5654        const IdentifierInfo *FnI = Fn->getIdentifier();
5655        if (FnI && FnI->isStr("_Block_copy")) {
5656          e = CE->getArg(0)->IgnoreParenCasts();
5657        }
5658      }
5659    }
5660  }
5661
5662  BlockExpr *block = dyn_cast<BlockExpr>(e);
5663  if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable))
5664    return 0;
5665
5666  FindCaptureVisitor visitor(S.Context, owner.Variable);
5667  visitor.Visit(block->getBlockDecl()->getBody());
5668  return visitor.Capturer;
5669}
5670
5671static void diagnoseRetainCycle(Sema &S, Expr *capturer,
5672                                RetainCycleOwner &owner) {
5673  assert(capturer);
5674  assert(owner.Variable && owner.Loc.isValid());
5675
5676  S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle)
5677    << owner.Variable << capturer->getSourceRange();
5678  S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner)
5679    << owner.Indirect << owner.Range;
5680}
5681
5682/// Check for a keyword selector that starts with the word 'add' or
5683/// 'set'.
5684static bool isSetterLikeSelector(Selector sel) {
5685  if (sel.isUnarySelector()) return false;
5686
5687  StringRef str = sel.getNameForSlot(0);
5688  while (!str.empty() && str.front() == '_') str = str.substr(1);
5689  if (str.startswith("set"))
5690    str = str.substr(3);
5691  else if (str.startswith("add")) {
5692    // Specially whitelist 'addOperationWithBlock:'.
5693    if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock"))
5694      return false;
5695    str = str.substr(3);
5696  }
5697  else
5698    return false;
5699
5700  if (str.empty()) return true;
5701  return !islower(str.front());
5702}
5703
5704/// Check a message send to see if it's likely to cause a retain cycle.
5705void Sema::checkRetainCycles(ObjCMessageExpr *msg) {
5706  // Only check instance methods whose selector looks like a setter.
5707  if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector()))
5708    return;
5709
5710  // Try to find a variable that the receiver is strongly owned by.
5711  RetainCycleOwner owner;
5712  if (msg->getReceiverKind() == ObjCMessageExpr::Instance) {
5713    if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner))
5714      return;
5715  } else {
5716    assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance);
5717    owner.Variable = getCurMethodDecl()->getSelfDecl();
5718    owner.Loc = msg->getSuperLoc();
5719    owner.Range = msg->getSuperLoc();
5720  }
5721
5722  // Check whether the receiver is captured by any of the arguments.
5723  for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i)
5724    if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner))
5725      return diagnoseRetainCycle(*this, capturer, owner);
5726}
5727
5728/// Check a property assign to see if it's likely to cause a retain cycle.
5729void Sema::checkRetainCycles(Expr *receiver, Expr *argument) {
5730  RetainCycleOwner owner;
5731  if (!findRetainCycleOwner(*this, receiver, owner))
5732    return;
5733
5734  if (Expr *capturer = findCapturingExpr(*this, argument, owner))
5735    diagnoseRetainCycle(*this, capturer, owner);
5736}
5737
5738void Sema::checkRetainCycles(VarDecl *Var, Expr *Init) {
5739  RetainCycleOwner Owner;
5740  if (!considerVariable(Var, /*DeclRefExpr=*/0, Owner))
5741    return;
5742
5743  // Because we don't have an expression for the variable, we have to set the
5744  // location explicitly here.
5745  Owner.Loc = Var->getLocation();
5746  Owner.Range = Var->getSourceRange();
5747
5748  if (Expr *Capturer = findCapturingExpr(*this, Init, Owner))
5749    diagnoseRetainCycle(*this, Capturer, Owner);
5750}
5751
5752static bool checkUnsafeAssignObject(Sema &S, SourceLocation Loc,
5753                                    Qualifiers::ObjCLifetime LT,
5754                                    Expr *RHS, bool isProperty) {
5755  // Strip off any implicit cast added to get to the one ARC-specific.
5756  while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) {
5757    if (cast->getCastKind() == CK_ARCConsumeObject) {
5758      S.Diag(Loc, diag::warn_arc_retained_assign)
5759        << (LT == Qualifiers::OCL_ExplicitNone)
5760        << (isProperty ? 0 : 1)
5761        << RHS->getSourceRange();
5762      return true;
5763    }
5764    RHS = cast->getSubExpr();
5765  }
5766  return false;
5767}
5768
5769static bool checkUnsafeAssignLiteral(Sema &S, SourceLocation Loc,
5770                                     Expr *RHS, bool isProperty) {
5771  // Check if RHS is an Objective-C object literal, which also can get
5772  // immediately zapped in a weak reference.  Note that we explicitly
5773  // allow ObjCStringLiterals, since those are designed to never really die.
5774  RHS = RHS->IgnoreParenImpCasts();
5775  unsigned kind = 4;
5776  switch (RHS->getStmtClass()) {
5777    default:
5778      break;
5779    case Stmt::ObjCDictionaryLiteralClass:
5780      kind = 0;
5781      break;
5782    case Stmt::ObjCArrayLiteralClass:
5783      kind = 1;
5784      break;
5785    case Stmt::BlockExprClass:
5786      kind = 2;
5787      break;
5788    case Stmt::ObjCBoxedExprClass:
5789      kind = 3;
5790      break;
5791  }
5792  if (kind < 4) {
5793    S.Diag(Loc, diag::warn_arc_literal_assign)
5794    << kind
5795    << (isProperty ? 0 : 1)
5796    << RHS->getSourceRange();
5797    return true;
5798  }
5799  return false;
5800}
5801
5802bool Sema::checkUnsafeAssigns(SourceLocation Loc,
5803                              QualType LHS, Expr *RHS) {
5804  Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime();
5805
5806  if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone)
5807    return false;
5808
5809  if (checkUnsafeAssignObject(*this, Loc, LT, RHS, false))
5810    return true;
5811
5812  if (LT == Qualifiers::OCL_Weak &&
5813      checkUnsafeAssignLiteral(*this, Loc, RHS, false))
5814    return true;
5815
5816  return false;
5817}
5818
5819void Sema::checkUnsafeExprAssigns(SourceLocation Loc,
5820                              Expr *LHS, Expr *RHS) {
5821  QualType LHSType;
5822  // PropertyRef on LHS type need be directly obtained from
5823  // its declaration as it has a PsuedoType.
5824  ObjCPropertyRefExpr *PRE
5825    = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens());
5826  if (PRE && !PRE->isImplicitProperty()) {
5827    const ObjCPropertyDecl *PD = PRE->getExplicitProperty();
5828    if (PD)
5829      LHSType = PD->getType();
5830  }
5831
5832  if (LHSType.isNull())
5833    LHSType = LHS->getType();
5834
5835  Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime();
5836
5837  if (LT == Qualifiers::OCL_Weak) {
5838    DiagnosticsEngine::Level Level =
5839      Diags.getDiagnosticLevel(diag::warn_arc_repeated_use_of_weak, Loc);
5840    if (Level != DiagnosticsEngine::Ignored)
5841      getCurFunction()->markSafeWeakUse(LHS);
5842  }
5843
5844  if (checkUnsafeAssigns(Loc, LHSType, RHS))
5845    return;
5846
5847  // FIXME. Check for other life times.
5848  if (LT != Qualifiers::OCL_None)
5849    return;
5850
5851  if (PRE) {
5852    if (PRE->isImplicitProperty())
5853      return;
5854    const ObjCPropertyDecl *PD = PRE->getExplicitProperty();
5855    if (!PD)
5856      return;
5857
5858    unsigned Attributes = PD->getPropertyAttributes();
5859    if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) {
5860      // when 'assign' attribute was not explicitly specified
5861      // by user, ignore it and rely on property type itself
5862      // for lifetime info.
5863      unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten();
5864      if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) &&
5865          LHSType->isObjCRetainableType())
5866        return;
5867
5868      while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) {
5869        if (cast->getCastKind() == CK_ARCConsumeObject) {
5870          Diag(Loc, diag::warn_arc_retained_property_assign)
5871          << RHS->getSourceRange();
5872          return;
5873        }
5874        RHS = cast->getSubExpr();
5875      }
5876    }
5877    else if (Attributes & ObjCPropertyDecl::OBJC_PR_weak) {
5878      if (checkUnsafeAssignObject(*this, Loc, Qualifiers::OCL_Weak, RHS, true))
5879        return;
5880      if (checkUnsafeAssignLiteral(*this, Loc, RHS, true))
5881        return;
5882    }
5883  }
5884}
5885
5886//===--- CHECK: Empty statement body (-Wempty-body) ---------------------===//
5887
5888namespace {
5889bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr,
5890                                 SourceLocation StmtLoc,
5891                                 const NullStmt *Body) {
5892  // Do not warn if the body is a macro that expands to nothing, e.g:
5893  //
5894  // #define CALL(x)
5895  // if (condition)
5896  //   CALL(0);
5897  //
5898  if (Body->hasLeadingEmptyMacro())
5899    return false;
5900
5901  // Get line numbers of statement and body.
5902  bool StmtLineInvalid;
5903  unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc,
5904                                                      &StmtLineInvalid);
5905  if (StmtLineInvalid)
5906    return false;
5907
5908  bool BodyLineInvalid;
5909  unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(),
5910                                                      &BodyLineInvalid);
5911  if (BodyLineInvalid)
5912    return false;
5913
5914  // Warn if null statement and body are on the same line.
5915  if (StmtLine != BodyLine)
5916    return false;
5917
5918  return true;
5919}
5920} // Unnamed namespace
5921
5922void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc,
5923                                 const Stmt *Body,
5924                                 unsigned DiagID) {
5925  // Since this is a syntactic check, don't emit diagnostic for template
5926  // instantiations, this just adds noise.
5927  if (CurrentInstantiationScope)
5928    return;
5929
5930  // The body should be a null statement.
5931  const NullStmt *NBody = dyn_cast<NullStmt>(Body);
5932  if (!NBody)
5933    return;
5934
5935  // Do the usual checks.
5936  if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody))
5937    return;
5938
5939  Diag(NBody->getSemiLoc(), DiagID);
5940  Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line);
5941}
5942
5943void Sema::DiagnoseEmptyLoopBody(const Stmt *S,
5944                                 const Stmt *PossibleBody) {
5945  assert(!CurrentInstantiationScope); // Ensured by caller
5946
5947  SourceLocation StmtLoc;
5948  const Stmt *Body;
5949  unsigned DiagID;
5950  if (const ForStmt *FS = dyn_cast<ForStmt>(S)) {
5951    StmtLoc = FS->getRParenLoc();
5952    Body = FS->getBody();
5953    DiagID = diag::warn_empty_for_body;
5954  } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) {
5955    StmtLoc = WS->getCond()->getSourceRange().getEnd();
5956    Body = WS->getBody();
5957    DiagID = diag::warn_empty_while_body;
5958  } else
5959    return; // Neither `for' nor `while'.
5960
5961  // The body should be a null statement.
5962  const NullStmt *NBody = dyn_cast<NullStmt>(Body);
5963  if (!NBody)
5964    return;
5965
5966  // Skip expensive checks if diagnostic is disabled.
5967  if (Diags.getDiagnosticLevel(DiagID, NBody->getSemiLoc()) ==
5968          DiagnosticsEngine::Ignored)
5969    return;
5970
5971  // Do the usual checks.
5972  if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody))
5973    return;
5974
5975  // `for(...);' and `while(...);' are popular idioms, so in order to keep
5976  // noise level low, emit diagnostics only if for/while is followed by a
5977  // CompoundStmt, e.g.:
5978  //    for (int i = 0; i < n; i++);
5979  //    {
5980  //      a(i);
5981  //    }
5982  // or if for/while is followed by a statement with more indentation
5983  // than for/while itself:
5984  //    for (int i = 0; i < n; i++);
5985  //      a(i);
5986  bool ProbableTypo = isa<CompoundStmt>(PossibleBody);
5987  if (!ProbableTypo) {
5988    bool BodyColInvalid;
5989    unsigned BodyCol = SourceMgr.getPresumedColumnNumber(
5990                             PossibleBody->getLocStart(),
5991                             &BodyColInvalid);
5992    if (BodyColInvalid)
5993      return;
5994
5995    bool StmtColInvalid;
5996    unsigned StmtCol = SourceMgr.getPresumedColumnNumber(
5997                             S->getLocStart(),
5998                             &StmtColInvalid);
5999    if (StmtColInvalid)
6000      return;
6001
6002    if (BodyCol > StmtCol)
6003      ProbableTypo = true;
6004  }
6005
6006  if (ProbableTypo) {
6007    Diag(NBody->getSemiLoc(), DiagID);
6008    Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line);
6009  }
6010}
6011
6012//===--- Layout compatibility ----------------------------------------------//
6013
6014namespace {
6015
6016bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2);
6017
6018/// \brief Check if two enumeration types are layout-compatible.
6019bool isLayoutCompatible(ASTContext &C, EnumDecl *ED1, EnumDecl *ED2) {
6020  // C++11 [dcl.enum] p8:
6021  // Two enumeration types are layout-compatible if they have the same
6022  // underlying type.
6023  return ED1->isComplete() && ED2->isComplete() &&
6024         C.hasSameType(ED1->getIntegerType(), ED2->getIntegerType());
6025}
6026
6027/// \brief Check if two fields are layout-compatible.
6028bool isLayoutCompatible(ASTContext &C, FieldDecl *Field1, FieldDecl *Field2) {
6029  if (!isLayoutCompatible(C, Field1->getType(), Field2->getType()))
6030    return false;
6031
6032  if (Field1->isBitField() != Field2->isBitField())
6033    return false;
6034
6035  if (Field1->isBitField()) {
6036    // Make sure that the bit-fields are the same length.
6037    unsigned Bits1 = Field1->getBitWidthValue(C);
6038    unsigned Bits2 = Field2->getBitWidthValue(C);
6039
6040    if (Bits1 != Bits2)
6041      return false;
6042  }
6043
6044  return true;
6045}
6046
6047/// \brief Check if two standard-layout structs are layout-compatible.
6048/// (C++11 [class.mem] p17)
6049bool isLayoutCompatibleStruct(ASTContext &C,
6050                              RecordDecl *RD1,
6051                              RecordDecl *RD2) {
6052  // If both records are C++ classes, check that base classes match.
6053  if (const CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(RD1)) {
6054    // If one of records is a CXXRecordDecl we are in C++ mode,
6055    // thus the other one is a CXXRecordDecl, too.
6056    const CXXRecordDecl *D2CXX = cast<CXXRecordDecl>(RD2);
6057    // Check number of base classes.
6058    if (D1CXX->getNumBases() != D2CXX->getNumBases())
6059      return false;
6060
6061    // Check the base classes.
6062    for (CXXRecordDecl::base_class_const_iterator
6063               Base1 = D1CXX->bases_begin(),
6064           BaseEnd1 = D1CXX->bases_end(),
6065              Base2 = D2CXX->bases_begin();
6066         Base1 != BaseEnd1;
6067         ++Base1, ++Base2) {
6068      if (!isLayoutCompatible(C, Base1->getType(), Base2->getType()))
6069        return false;
6070    }
6071  } else if (const CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(RD2)) {
6072    // If only RD2 is a C++ class, it should have zero base classes.
6073    if (D2CXX->getNumBases() > 0)
6074      return false;
6075  }
6076
6077  // Check the fields.
6078  RecordDecl::field_iterator Field2 = RD2->field_begin(),
6079                             Field2End = RD2->field_end(),
6080                             Field1 = RD1->field_begin(),
6081                             Field1End = RD1->field_end();
6082  for ( ; Field1 != Field1End && Field2 != Field2End; ++Field1, ++Field2) {
6083    if (!isLayoutCompatible(C, *Field1, *Field2))
6084      return false;
6085  }
6086  if (Field1 != Field1End || Field2 != Field2End)
6087    return false;
6088
6089  return true;
6090}
6091
6092/// \brief Check if two standard-layout unions are layout-compatible.
6093/// (C++11 [class.mem] p18)
6094bool isLayoutCompatibleUnion(ASTContext &C,
6095                             RecordDecl *RD1,
6096                             RecordDecl *RD2) {
6097  llvm::SmallPtrSet<FieldDecl *, 8> UnmatchedFields;
6098  for (RecordDecl::field_iterator Field2 = RD2->field_begin(),
6099                                  Field2End = RD2->field_end();
6100       Field2 != Field2End; ++Field2) {
6101    UnmatchedFields.insert(*Field2);
6102  }
6103
6104  for (RecordDecl::field_iterator Field1 = RD1->field_begin(),
6105                                  Field1End = RD1->field_end();
6106       Field1 != Field1End; ++Field1) {
6107    llvm::SmallPtrSet<FieldDecl *, 8>::iterator
6108        I = UnmatchedFields.begin(),
6109        E = UnmatchedFields.end();
6110
6111    for ( ; I != E; ++I) {
6112      if (isLayoutCompatible(C, *Field1, *I)) {
6113        bool Result = UnmatchedFields.erase(*I);
6114        (void) Result;
6115        assert(Result);
6116        break;
6117      }
6118    }
6119    if (I == E)
6120      return false;
6121  }
6122
6123  return UnmatchedFields.empty();
6124}
6125
6126bool isLayoutCompatible(ASTContext &C, RecordDecl *RD1, RecordDecl *RD2) {
6127  if (RD1->isUnion() != RD2->isUnion())
6128    return false;
6129
6130  if (RD1->isUnion())
6131    return isLayoutCompatibleUnion(C, RD1, RD2);
6132  else
6133    return isLayoutCompatibleStruct(C, RD1, RD2);
6134}
6135
6136/// \brief Check if two types are layout-compatible in C++11 sense.
6137bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2) {
6138  if (T1.isNull() || T2.isNull())
6139    return false;
6140
6141  // C++11 [basic.types] p11:
6142  // If two types T1 and T2 are the same type, then T1 and T2 are
6143  // layout-compatible types.
6144  if (C.hasSameType(T1, T2))
6145    return true;
6146
6147  T1 = T1.getCanonicalType().getUnqualifiedType();
6148  T2 = T2.getCanonicalType().getUnqualifiedType();
6149
6150  const Type::TypeClass TC1 = T1->getTypeClass();
6151  const Type::TypeClass TC2 = T2->getTypeClass();
6152
6153  if (TC1 != TC2)
6154    return false;
6155
6156  if (TC1 == Type::Enum) {
6157    return isLayoutCompatible(C,
6158                              cast<EnumType>(T1)->getDecl(),
6159                              cast<EnumType>(T2)->getDecl());
6160  } else if (TC1 == Type::Record) {
6161    if (!T1->isStandardLayoutType() || !T2->isStandardLayoutType())
6162      return false;
6163
6164    return isLayoutCompatible(C,
6165                              cast<RecordType>(T1)->getDecl(),
6166                              cast<RecordType>(T2)->getDecl());
6167  }
6168
6169  return false;
6170}
6171}
6172
6173//===--- CHECK: pointer_with_type_tag attribute: datatypes should match ----//
6174
6175namespace {
6176/// \brief Given a type tag expression find the type tag itself.
6177///
6178/// \param TypeExpr Type tag expression, as it appears in user's code.
6179///
6180/// \param VD Declaration of an identifier that appears in a type tag.
6181///
6182/// \param MagicValue Type tag magic value.
6183bool FindTypeTagExpr(const Expr *TypeExpr, const ASTContext &Ctx,
6184                     const ValueDecl **VD, uint64_t *MagicValue) {
6185  while(true) {
6186    if (!TypeExpr)
6187      return false;
6188
6189    TypeExpr = TypeExpr->IgnoreParenImpCasts()->IgnoreParenCasts();
6190
6191    switch (TypeExpr->getStmtClass()) {
6192    case Stmt::UnaryOperatorClass: {
6193      const UnaryOperator *UO = cast<UnaryOperator>(TypeExpr);
6194      if (UO->getOpcode() == UO_AddrOf || UO->getOpcode() == UO_Deref) {
6195        TypeExpr = UO->getSubExpr();
6196        continue;
6197      }
6198      return false;
6199    }
6200
6201    case Stmt::DeclRefExprClass: {
6202      const DeclRefExpr *DRE = cast<DeclRefExpr>(TypeExpr);
6203      *VD = DRE->getDecl();
6204      return true;
6205    }
6206
6207    case Stmt::IntegerLiteralClass: {
6208      const IntegerLiteral *IL = cast<IntegerLiteral>(TypeExpr);
6209      llvm::APInt MagicValueAPInt = IL->getValue();
6210      if (MagicValueAPInt.getActiveBits() <= 64) {
6211        *MagicValue = MagicValueAPInt.getZExtValue();
6212        return true;
6213      } else
6214        return false;
6215    }
6216
6217    case Stmt::BinaryConditionalOperatorClass:
6218    case Stmt::ConditionalOperatorClass: {
6219      const AbstractConditionalOperator *ACO =
6220          cast<AbstractConditionalOperator>(TypeExpr);
6221      bool Result;
6222      if (ACO->getCond()->EvaluateAsBooleanCondition(Result, Ctx)) {
6223        if (Result)
6224          TypeExpr = ACO->getTrueExpr();
6225        else
6226          TypeExpr = ACO->getFalseExpr();
6227        continue;
6228      }
6229      return false;
6230    }
6231
6232    case Stmt::BinaryOperatorClass: {
6233      const BinaryOperator *BO = cast<BinaryOperator>(TypeExpr);
6234      if (BO->getOpcode() == BO_Comma) {
6235        TypeExpr = BO->getRHS();
6236        continue;
6237      }
6238      return false;
6239    }
6240
6241    default:
6242      return false;
6243    }
6244  }
6245}
6246
6247/// \brief Retrieve the C type corresponding to type tag TypeExpr.
6248///
6249/// \param TypeExpr Expression that specifies a type tag.
6250///
6251/// \param MagicValues Registered magic values.
6252///
6253/// \param FoundWrongKind Set to true if a type tag was found, but of a wrong
6254///        kind.
6255///
6256/// \param TypeInfo Information about the corresponding C type.
6257///
6258/// \returns true if the corresponding C type was found.
6259bool GetMatchingCType(
6260        const IdentifierInfo *ArgumentKind,
6261        const Expr *TypeExpr, const ASTContext &Ctx,
6262        const llvm::DenseMap<Sema::TypeTagMagicValue,
6263                             Sema::TypeTagData> *MagicValues,
6264        bool &FoundWrongKind,
6265        Sema::TypeTagData &TypeInfo) {
6266  FoundWrongKind = false;
6267
6268  // Variable declaration that has type_tag_for_datatype attribute.
6269  const ValueDecl *VD = NULL;
6270
6271  uint64_t MagicValue;
6272
6273  if (!FindTypeTagExpr(TypeExpr, Ctx, &VD, &MagicValue))
6274    return false;
6275
6276  if (VD) {
6277    for (specific_attr_iterator<TypeTagForDatatypeAttr>
6278             I = VD->specific_attr_begin<TypeTagForDatatypeAttr>(),
6279             E = VD->specific_attr_end<TypeTagForDatatypeAttr>();
6280         I != E; ++I) {
6281      if (I->getArgumentKind() != ArgumentKind) {
6282        FoundWrongKind = true;
6283        return false;
6284      }
6285      TypeInfo.Type = I->getMatchingCType();
6286      TypeInfo.LayoutCompatible = I->getLayoutCompatible();
6287      TypeInfo.MustBeNull = I->getMustBeNull();
6288      return true;
6289    }
6290    return false;
6291  }
6292
6293  if (!MagicValues)
6294    return false;
6295
6296  llvm::DenseMap<Sema::TypeTagMagicValue,
6297                 Sema::TypeTagData>::const_iterator I =
6298      MagicValues->find(std::make_pair(ArgumentKind, MagicValue));
6299  if (I == MagicValues->end())
6300    return false;
6301
6302  TypeInfo = I->second;
6303  return true;
6304}
6305} // unnamed namespace
6306
6307void Sema::RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind,
6308                                      uint64_t MagicValue, QualType Type,
6309                                      bool LayoutCompatible,
6310                                      bool MustBeNull) {
6311  if (!TypeTagForDatatypeMagicValues)
6312    TypeTagForDatatypeMagicValues.reset(
6313        new llvm::DenseMap<TypeTagMagicValue, TypeTagData>);
6314
6315  TypeTagMagicValue Magic(ArgumentKind, MagicValue);
6316  (*TypeTagForDatatypeMagicValues)[Magic] =
6317      TypeTagData(Type, LayoutCompatible, MustBeNull);
6318}
6319
6320namespace {
6321bool IsSameCharType(QualType T1, QualType T2) {
6322  const BuiltinType *BT1 = T1->getAs<BuiltinType>();
6323  if (!BT1)
6324    return false;
6325
6326  const BuiltinType *BT2 = T2->getAs<BuiltinType>();
6327  if (!BT2)
6328    return false;
6329
6330  BuiltinType::Kind T1Kind = BT1->getKind();
6331  BuiltinType::Kind T2Kind = BT2->getKind();
6332
6333  return (T1Kind == BuiltinType::SChar  && T2Kind == BuiltinType::Char_S) ||
6334         (T1Kind == BuiltinType::UChar  && T2Kind == BuiltinType::Char_U) ||
6335         (T1Kind == BuiltinType::Char_U && T2Kind == BuiltinType::UChar) ||
6336         (T1Kind == BuiltinType::Char_S && T2Kind == BuiltinType::SChar);
6337}
6338} // unnamed namespace
6339
6340void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr,
6341                                    const Expr * const *ExprArgs) {
6342  const IdentifierInfo *ArgumentKind = Attr->getArgumentKind();
6343  bool IsPointerAttr = Attr->getIsPointer();
6344
6345  const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()];
6346  bool FoundWrongKind;
6347  TypeTagData TypeInfo;
6348  if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context,
6349                        TypeTagForDatatypeMagicValues.get(),
6350                        FoundWrongKind, TypeInfo)) {
6351    if (FoundWrongKind)
6352      Diag(TypeTagExpr->getExprLoc(),
6353           diag::warn_type_tag_for_datatype_wrong_kind)
6354        << TypeTagExpr->getSourceRange();
6355    return;
6356  }
6357
6358  const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()];
6359  if (IsPointerAttr) {
6360    // Skip implicit cast of pointer to `void *' (as a function argument).
6361    if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr))
6362      if (ICE->getType()->isVoidPointerType() &&
6363          ICE->getCastKind() == CK_BitCast)
6364        ArgumentExpr = ICE->getSubExpr();
6365  }
6366  QualType ArgumentType = ArgumentExpr->getType();
6367
6368  // Passing a `void*' pointer shouldn't trigger a warning.
6369  if (IsPointerAttr && ArgumentType->isVoidPointerType())
6370    return;
6371
6372  if (TypeInfo.MustBeNull) {
6373    // Type tag with matching void type requires a null pointer.
6374    if (!ArgumentExpr->isNullPointerConstant(Context,
6375                                             Expr::NPC_ValueDependentIsNotNull)) {
6376      Diag(ArgumentExpr->getExprLoc(),
6377           diag::warn_type_safety_null_pointer_required)
6378          << ArgumentKind->getName()
6379          << ArgumentExpr->getSourceRange()
6380          << TypeTagExpr->getSourceRange();
6381    }
6382    return;
6383  }
6384
6385  QualType RequiredType = TypeInfo.Type;
6386  if (IsPointerAttr)
6387    RequiredType = Context.getPointerType(RequiredType);
6388
6389  bool mismatch = false;
6390  if (!TypeInfo.LayoutCompatible) {
6391    mismatch = !Context.hasSameType(ArgumentType, RequiredType);
6392
6393    // C++11 [basic.fundamental] p1:
6394    // Plain char, signed char, and unsigned char are three distinct types.
6395    //
6396    // But we treat plain `char' as equivalent to `signed char' or `unsigned
6397    // char' depending on the current char signedness mode.
6398    if (mismatch)
6399      if ((IsPointerAttr && IsSameCharType(ArgumentType->getPointeeType(),
6400                                           RequiredType->getPointeeType())) ||
6401          (!IsPointerAttr && IsSameCharType(ArgumentType, RequiredType)))
6402        mismatch = false;
6403  } else
6404    if (IsPointerAttr)
6405      mismatch = !isLayoutCompatible(Context,
6406                                     ArgumentType->getPointeeType(),
6407                                     RequiredType->getPointeeType());
6408    else
6409      mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType);
6410
6411  if (mismatch)
6412    Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch)
6413        << ArgumentType << ArgumentKind->getName()
6414        << TypeInfo.LayoutCompatible << RequiredType
6415        << ArgumentExpr->getSourceRange()
6416        << TypeTagExpr->getSourceRange();
6417}
6418