SemaChecking.cpp revision 94ff8e1f57c6382d91d0de981a4f311509d83e37 
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/Initialization.h"
16#include "clang/Sema/Sema.h"
17#include "clang/Sema/SemaInternal.h"
18#include "clang/Sema/Initialization.h"
19#include "clang/Sema/Lookup.h"
20#include "clang/Sema/ScopeInfo.h"
21#include "clang/Analysis/Analyses/FormatString.h"
22#include "clang/AST/ASTContext.h"
23#include "clang/AST/CharUnits.h"
24#include "clang/AST/DeclCXX.h"
25#include "clang/AST/DeclObjC.h"
26#include "clang/AST/Expr.h"
27#include "clang/AST/ExprCXX.h"
28#include "clang/AST/ExprObjC.h"
29#include "clang/AST/EvaluatedExprVisitor.h"
30#include "clang/AST/DeclObjC.h"
31#include "clang/AST/StmtCXX.h"
32#include "clang/AST/StmtObjC.h"
33#include "clang/Lex/Preprocessor.h"
34#include "llvm/ADT/BitVector.h"
35#include "llvm/ADT/SmallString.h"
36#include "llvm/ADT/STLExtras.h"
37#include "llvm/Support/raw_ostream.h"
38#include "clang/Basic/TargetBuiltins.h"
39#include "clang/Basic/TargetInfo.h"
40#include "clang/Basic/ConvertUTF.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  // FIXME: This mechanism should be abstracted to be less fragile and
499  // more efficient. For example, just map function ids to custom
500  // handlers.
501
502  // Printf and scanf checking.
503  bool HandledFormatString = false;
504  for (specific_attr_iterator<FormatAttr>
505         I = FDecl->specific_attr_begin<FormatAttr>(),
506         E = FDecl->specific_attr_end<FormatAttr>(); I != E ; ++I)
507    if (CheckFormatArguments(*I, Args, NumArgs, IsMemberFunction, CallType,
508                             Loc, Range))
509        HandledFormatString = true;
510
511  // Refuse POD arguments that weren't caught by the format string
512  // checks above.
513  if (!HandledFormatString && CallType != VariadicDoesNotApply)
514    for (unsigned ArgIdx = NumProtoArgs; ArgIdx < NumArgs; ++ArgIdx)
515      variadicArgumentPODCheck(Args[ArgIdx], CallType);
516
517  for (specific_attr_iterator<NonNullAttr>
518         I = FDecl->specific_attr_begin<NonNullAttr>(),
519         E = FDecl->specific_attr_end<NonNullAttr>(); I != E; ++I)
520    CheckNonNullArguments(*I, Args, Loc);
521
522  // Type safety checking.
523  for (specific_attr_iterator<ArgumentWithTypeTagAttr>
524         i = FDecl->specific_attr_begin<ArgumentWithTypeTagAttr>(),
525         e = FDecl->specific_attr_end<ArgumentWithTypeTagAttr>(); i != e; ++i) {
526    CheckArgumentWithTypeTag(*i, Args);
527  }
528}
529
530/// CheckConstructorCall - Check a constructor call for correctness and safety
531/// properties not enforced by the C type system.
532void Sema::CheckConstructorCall(FunctionDecl *FDecl, Expr **Args,
533                                unsigned NumArgs,
534                                const FunctionProtoType *Proto,
535                                SourceLocation Loc) {
536  VariadicCallType CallType =
537    Proto->isVariadic() ? VariadicConstructor : VariadicDoesNotApply;
538  checkCall(FDecl, Args, NumArgs, Proto->getNumArgs(),
539            /*IsMemberFunction=*/true, Loc, SourceRange(), CallType);
540}
541
542/// CheckFunctionCall - Check a direct function call for various correctness
543/// and safety properties not strictly enforced by the C type system.
544bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall,
545                             const FunctionProtoType *Proto) {
546  bool IsMemberFunction = isa<CXXMemberCallExpr>(TheCall);
547  VariadicCallType CallType = getVariadicCallType(FDecl, Proto,
548                                                  TheCall->getCallee());
549  unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0;
550  checkCall(FDecl, TheCall->getArgs(), TheCall->getNumArgs(), NumProtoArgs,
551            IsMemberFunction, TheCall->getRParenLoc(),
552            TheCall->getCallee()->getSourceRange(), CallType);
553
554  IdentifierInfo *FnInfo = FDecl->getIdentifier();
555  // None of the checks below are needed for functions that don't have
556  // simple names (e.g., C++ conversion functions).
557  if (!FnInfo)
558    return false;
559
560  unsigned CMId = FDecl->getMemoryFunctionKind();
561  if (CMId == 0)
562    return false;
563
564  // Handle memory setting and copying functions.
565  if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat)
566    CheckStrlcpycatArguments(TheCall, FnInfo);
567  else if (CMId == Builtin::BIstrncat)
568    CheckStrncatArguments(TheCall, FnInfo);
569  else
570    CheckMemaccessArguments(TheCall, CMId, FnInfo);
571
572  return false;
573}
574
575bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac,
576                               Expr **Args, unsigned NumArgs) {
577  VariadicCallType CallType =
578      Method->isVariadic() ? VariadicMethod : VariadicDoesNotApply;
579
580  checkCall(Method, Args, NumArgs, Method->param_size(),
581            /*IsMemberFunction=*/false,
582            lbrac, Method->getSourceRange(), CallType);
583
584  return false;
585}
586
587bool Sema::CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall,
588                          const FunctionProtoType *Proto) {
589  const VarDecl *V = dyn_cast<VarDecl>(NDecl);
590  if (!V)
591    return false;
592
593  QualType Ty = V->getType();
594  if (!Ty->isBlockPointerType())
595    return false;
596
597  VariadicCallType CallType =
598      Proto && Proto->isVariadic() ? VariadicBlock : VariadicDoesNotApply ;
599  unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0;
600
601  checkCall(NDecl, TheCall->getArgs(), TheCall->getNumArgs(),
602            NumProtoArgs, /*IsMemberFunction=*/false,
603            TheCall->getRParenLoc(),
604            TheCall->getCallee()->getSourceRange(), CallType);
605
606  return false;
607}
608
609ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult,
610                                         AtomicExpr::AtomicOp Op) {
611  CallExpr *TheCall = cast<CallExpr>(TheCallResult.get());
612  DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
613
614  // All these operations take one of the following forms:
615  enum {
616    // C    __c11_atomic_init(A *, C)
617    Init,
618    // C    __c11_atomic_load(A *, int)
619    Load,
620    // void __atomic_load(A *, CP, int)
621    Copy,
622    // C    __c11_atomic_add(A *, M, int)
623    Arithmetic,
624    // C    __atomic_exchange_n(A *, CP, int)
625    Xchg,
626    // void __atomic_exchange(A *, C *, CP, int)
627    GNUXchg,
628    // bool __c11_atomic_compare_exchange_strong(A *, C *, CP, int, int)
629    C11CmpXchg,
630    // bool __atomic_compare_exchange(A *, C *, CP, bool, int, int)
631    GNUCmpXchg
632  } Form = Init;
633  const unsigned NumArgs[] = { 2, 2, 3, 3, 3, 4, 5, 6 };
634  const unsigned NumVals[] = { 1, 0, 1, 1, 1, 2, 2, 3 };
635  // where:
636  //   C is an appropriate type,
637  //   A is volatile _Atomic(C) for __c11 builtins and is C for GNU builtins,
638  //   CP is C for __c11 builtins and GNU _n builtins and is C * otherwise,
639  //   M is C if C is an integer, and ptrdiff_t if C is a pointer, and
640  //   the int parameters are for orderings.
641
642  assert(AtomicExpr::AO__c11_atomic_init == 0 &&
643         AtomicExpr::AO__c11_atomic_fetch_xor + 1 == AtomicExpr::AO__atomic_load
644         && "need to update code for modified C11 atomics");
645  bool IsC11 = Op >= AtomicExpr::AO__c11_atomic_init &&
646               Op <= AtomicExpr::AO__c11_atomic_fetch_xor;
647  bool IsN = Op == AtomicExpr::AO__atomic_load_n ||
648             Op == AtomicExpr::AO__atomic_store_n ||
649             Op == AtomicExpr::AO__atomic_exchange_n ||
650             Op == AtomicExpr::AO__atomic_compare_exchange_n;
651  bool IsAddSub = false;
652
653  switch (Op) {
654  case AtomicExpr::AO__c11_atomic_init:
655    Form = Init;
656    break;
657
658  case AtomicExpr::AO__c11_atomic_load:
659  case AtomicExpr::AO__atomic_load_n:
660    Form = Load;
661    break;
662
663  case AtomicExpr::AO__c11_atomic_store:
664  case AtomicExpr::AO__atomic_load:
665  case AtomicExpr::AO__atomic_store:
666  case AtomicExpr::AO__atomic_store_n:
667    Form = Copy;
668    break;
669
670  case AtomicExpr::AO__c11_atomic_fetch_add:
671  case AtomicExpr::AO__c11_atomic_fetch_sub:
672  case AtomicExpr::AO__atomic_fetch_add:
673  case AtomicExpr::AO__atomic_fetch_sub:
674  case AtomicExpr::AO__atomic_add_fetch:
675  case AtomicExpr::AO__atomic_sub_fetch:
676    IsAddSub = true;
677    // Fall through.
678  case AtomicExpr::AO__c11_atomic_fetch_and:
679  case AtomicExpr::AO__c11_atomic_fetch_or:
680  case AtomicExpr::AO__c11_atomic_fetch_xor:
681  case AtomicExpr::AO__atomic_fetch_and:
682  case AtomicExpr::AO__atomic_fetch_or:
683  case AtomicExpr::AO__atomic_fetch_xor:
684  case AtomicExpr::AO__atomic_fetch_nand:
685  case AtomicExpr::AO__atomic_and_fetch:
686  case AtomicExpr::AO__atomic_or_fetch:
687  case AtomicExpr::AO__atomic_xor_fetch:
688  case AtomicExpr::AO__atomic_nand_fetch:
689    Form = Arithmetic;
690    break;
691
692  case AtomicExpr::AO__c11_atomic_exchange:
693  case AtomicExpr::AO__atomic_exchange_n:
694    Form = Xchg;
695    break;
696
697  case AtomicExpr::AO__atomic_exchange:
698    Form = GNUXchg;
699    break;
700
701  case AtomicExpr::AO__c11_atomic_compare_exchange_strong:
702  case AtomicExpr::AO__c11_atomic_compare_exchange_weak:
703    Form = C11CmpXchg;
704    break;
705
706  case AtomicExpr::AO__atomic_compare_exchange:
707  case AtomicExpr::AO__atomic_compare_exchange_n:
708    Form = GNUCmpXchg;
709    break;
710  }
711
712  // Check we have the right number of arguments.
713  if (TheCall->getNumArgs() < NumArgs[Form]) {
714    Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
715      << 0 << NumArgs[Form] << TheCall->getNumArgs()
716      << TheCall->getCallee()->getSourceRange();
717    return ExprError();
718  } else if (TheCall->getNumArgs() > NumArgs[Form]) {
719    Diag(TheCall->getArg(NumArgs[Form])->getLocStart(),
720         diag::err_typecheck_call_too_many_args)
721      << 0 << NumArgs[Form] << TheCall->getNumArgs()
722      << TheCall->getCallee()->getSourceRange();
723    return ExprError();
724  }
725
726  // Inspect the first argument of the atomic operation.
727  Expr *Ptr = TheCall->getArg(0);
728  Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get();
729  const PointerType *pointerType = Ptr->getType()->getAs<PointerType>();
730  if (!pointerType) {
731    Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
732      << Ptr->getType() << Ptr->getSourceRange();
733    return ExprError();
734  }
735
736  // For a __c11 builtin, this should be a pointer to an _Atomic type.
737  QualType AtomTy = pointerType->getPointeeType(); // 'A'
738  QualType ValType = AtomTy; // 'C'
739  if (IsC11) {
740    if (!AtomTy->isAtomicType()) {
741      Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic)
742        << Ptr->getType() << Ptr->getSourceRange();
743      return ExprError();
744    }
745    if (AtomTy.isConstQualified()) {
746      Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_atomic)
747        << Ptr->getType() << Ptr->getSourceRange();
748      return ExprError();
749    }
750    ValType = AtomTy->getAs<AtomicType>()->getValueType();
751  }
752
753  // For an arithmetic operation, the implied arithmetic must be well-formed.
754  if (Form == Arithmetic) {
755    // gcc does not enforce these rules for GNU atomics, but we do so for sanity.
756    if (IsAddSub && !ValType->isIntegerType() && !ValType->isPointerType()) {
757      Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr)
758        << IsC11 << Ptr->getType() << Ptr->getSourceRange();
759      return ExprError();
760    }
761    if (!IsAddSub && !ValType->isIntegerType()) {
762      Diag(DRE->getLocStart(), diag::err_atomic_op_bitwise_needs_atomic_int)
763        << IsC11 << Ptr->getType() << Ptr->getSourceRange();
764      return ExprError();
765    }
766  } else if (IsN && !ValType->isIntegerType() && !ValType->isPointerType()) {
767    // For __atomic_*_n operations, the value type must be a scalar integral or
768    // pointer type which is 1, 2, 4, 8 or 16 bytes in length.
769    Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr)
770      << IsC11 << Ptr->getType() << Ptr->getSourceRange();
771    return ExprError();
772  }
773
774  if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context)) {
775    // For GNU atomics, require a trivially-copyable type. This is not part of
776    // the GNU atomics specification, but we enforce it for sanity.
777    Diag(DRE->getLocStart(), diag::err_atomic_op_needs_trivial_copy)
778      << Ptr->getType() << Ptr->getSourceRange();
779    return ExprError();
780  }
781
782  // FIXME: For any builtin other than a load, the ValType must not be
783  // const-qualified.
784
785  switch (ValType.getObjCLifetime()) {
786  case Qualifiers::OCL_None:
787  case Qualifiers::OCL_ExplicitNone:
788    // okay
789    break;
790
791  case Qualifiers::OCL_Weak:
792  case Qualifiers::OCL_Strong:
793  case Qualifiers::OCL_Autoreleasing:
794    // FIXME: Can this happen? By this point, ValType should be known
795    // to be trivially copyable.
796    Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
797      << ValType << Ptr->getSourceRange();
798    return ExprError();
799  }
800
801  QualType ResultType = ValType;
802  if (Form == Copy || Form == GNUXchg || Form == Init)
803    ResultType = Context.VoidTy;
804  else if (Form == C11CmpXchg || Form == GNUCmpXchg)
805    ResultType = Context.BoolTy;
806
807  // The type of a parameter passed 'by value'. In the GNU atomics, such
808  // arguments are actually passed as pointers.
809  QualType ByValType = ValType; // 'CP'
810  if (!IsC11 && !IsN)
811    ByValType = Ptr->getType();
812
813  // The first argument --- the pointer --- has a fixed type; we
814  // deduce the types of the rest of the arguments accordingly.  Walk
815  // the remaining arguments, converting them to the deduced value type.
816  for (unsigned i = 1; i != NumArgs[Form]; ++i) {
817    QualType Ty;
818    if (i < NumVals[Form] + 1) {
819      switch (i) {
820      case 1:
821        // The second argument is the non-atomic operand. For arithmetic, this
822        // is always passed by value, and for a compare_exchange it is always
823        // passed by address. For the rest, GNU uses by-address and C11 uses
824        // by-value.
825        assert(Form != Load);
826        if (Form == Init || (Form == Arithmetic && ValType->isIntegerType()))
827          Ty = ValType;
828        else if (Form == Copy || Form == Xchg)
829          Ty = ByValType;
830        else if (Form == Arithmetic)
831          Ty = Context.getPointerDiffType();
832        else
833          Ty = Context.getPointerType(ValType.getUnqualifiedType());
834        break;
835      case 2:
836        // The third argument to compare_exchange / GNU exchange is a
837        // (pointer to a) desired value.
838        Ty = ByValType;
839        break;
840      case 3:
841        // The fourth argument to GNU compare_exchange is a 'weak' flag.
842        Ty = Context.BoolTy;
843        break;
844      }
845    } else {
846      // The order(s) are always converted to int.
847      Ty = Context.IntTy;
848    }
849
850    InitializedEntity Entity =
851        InitializedEntity::InitializeParameter(Context, Ty, false);
852    ExprResult Arg = TheCall->getArg(i);
853    Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
854    if (Arg.isInvalid())
855      return true;
856    TheCall->setArg(i, Arg.get());
857  }
858
859  // Permute the arguments into a 'consistent' order.
860  SmallVector<Expr*, 5> SubExprs;
861  SubExprs.push_back(Ptr);
862  switch (Form) {
863  case Init:
864    // Note, AtomicExpr::getVal1() has a special case for this atomic.
865    SubExprs.push_back(TheCall->getArg(1)); // Val1
866    break;
867  case Load:
868    SubExprs.push_back(TheCall->getArg(1)); // Order
869    break;
870  case Copy:
871  case Arithmetic:
872  case Xchg:
873    SubExprs.push_back(TheCall->getArg(2)); // Order
874    SubExprs.push_back(TheCall->getArg(1)); // Val1
875    break;
876  case GNUXchg:
877    // Note, AtomicExpr::getVal2() has a special case for this atomic.
878    SubExprs.push_back(TheCall->getArg(3)); // Order
879    SubExprs.push_back(TheCall->getArg(1)); // Val1
880    SubExprs.push_back(TheCall->getArg(2)); // Val2
881    break;
882  case C11CmpXchg:
883    SubExprs.push_back(TheCall->getArg(3)); // Order
884    SubExprs.push_back(TheCall->getArg(1)); // Val1
885    SubExprs.push_back(TheCall->getArg(4)); // OrderFail
886    SubExprs.push_back(TheCall->getArg(2)); // Val2
887    break;
888  case GNUCmpXchg:
889    SubExprs.push_back(TheCall->getArg(4)); // Order
890    SubExprs.push_back(TheCall->getArg(1)); // Val1
891    SubExprs.push_back(TheCall->getArg(5)); // OrderFail
892    SubExprs.push_back(TheCall->getArg(2)); // Val2
893    SubExprs.push_back(TheCall->getArg(3)); // Weak
894    break;
895  }
896
897  return Owned(new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(),
898                                        SubExprs, ResultType, Op,
899                                        TheCall->getRParenLoc()));
900}
901
902
903/// checkBuiltinArgument - Given a call to a builtin function, perform
904/// normal type-checking on the given argument, updating the call in
905/// place.  This is useful when a builtin function requires custom
906/// type-checking for some of its arguments but not necessarily all of
907/// them.
908///
909/// Returns true on error.
910static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) {
911  FunctionDecl *Fn = E->getDirectCallee();
912  assert(Fn && "builtin call without direct callee!");
913
914  ParmVarDecl *Param = Fn->getParamDecl(ArgIndex);
915  InitializedEntity Entity =
916    InitializedEntity::InitializeParameter(S.Context, Param);
917
918  ExprResult Arg = E->getArg(0);
919  Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg);
920  if (Arg.isInvalid())
921    return true;
922
923  E->setArg(ArgIndex, Arg.take());
924  return false;
925}
926
927/// SemaBuiltinAtomicOverloaded - We have a call to a function like
928/// __sync_fetch_and_add, which is an overloaded function based on the pointer
929/// type of its first argument.  The main ActOnCallExpr routines have already
930/// promoted the types of arguments because all of these calls are prototyped as
931/// void(...).
932///
933/// This function goes through and does final semantic checking for these
934/// builtins,
935ExprResult
936Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) {
937  CallExpr *TheCall = (CallExpr *)TheCallResult.get();
938  DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
939  FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
940
941  // Ensure that we have at least one argument to do type inference from.
942  if (TheCall->getNumArgs() < 1) {
943    Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
944      << 0 << 1 << TheCall->getNumArgs()
945      << TheCall->getCallee()->getSourceRange();
946    return ExprError();
947  }
948
949  // Inspect the first argument of the atomic builtin.  This should always be
950  // a pointer type, whose element is an integral scalar or pointer type.
951  // Because it is a pointer type, we don't have to worry about any implicit
952  // casts here.
953  // FIXME: We don't allow floating point scalars as input.
954  Expr *FirstArg = TheCall->getArg(0);
955  ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg);
956  if (FirstArgResult.isInvalid())
957    return ExprError();
958  FirstArg = FirstArgResult.take();
959  TheCall->setArg(0, FirstArg);
960
961  const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>();
962  if (!pointerType) {
963    Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
964      << FirstArg->getType() << FirstArg->getSourceRange();
965    return ExprError();
966  }
967
968  QualType ValType = pointerType->getPointeeType();
969  if (!ValType->isIntegerType() && !ValType->isAnyPointerType() &&
970      !ValType->isBlockPointerType()) {
971    Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr)
972      << FirstArg->getType() << FirstArg->getSourceRange();
973    return ExprError();
974  }
975
976  switch (ValType.getObjCLifetime()) {
977  case Qualifiers::OCL_None:
978  case Qualifiers::OCL_ExplicitNone:
979    // okay
980    break;
981
982  case Qualifiers::OCL_Weak:
983  case Qualifiers::OCL_Strong:
984  case Qualifiers::OCL_Autoreleasing:
985    Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
986      << ValType << FirstArg->getSourceRange();
987    return ExprError();
988  }
989
990  // Strip any qualifiers off ValType.
991  ValType = ValType.getUnqualifiedType();
992
993  // The majority of builtins return a value, but a few have special return
994  // types, so allow them to override appropriately below.
995  QualType ResultType = ValType;
996
997  // We need to figure out which concrete builtin this maps onto.  For example,
998  // __sync_fetch_and_add with a 2 byte object turns into
999  // __sync_fetch_and_add_2.
1000#define BUILTIN_ROW(x) \
1001  { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \
1002    Builtin::BI##x##_8, Builtin::BI##x##_16 }
1003
1004  static const unsigned BuiltinIndices[][5] = {
1005    BUILTIN_ROW(__sync_fetch_and_add),
1006    BUILTIN_ROW(__sync_fetch_and_sub),
1007    BUILTIN_ROW(__sync_fetch_and_or),
1008    BUILTIN_ROW(__sync_fetch_and_and),
1009    BUILTIN_ROW(__sync_fetch_and_xor),
1010
1011    BUILTIN_ROW(__sync_add_and_fetch),
1012    BUILTIN_ROW(__sync_sub_and_fetch),
1013    BUILTIN_ROW(__sync_and_and_fetch),
1014    BUILTIN_ROW(__sync_or_and_fetch),
1015    BUILTIN_ROW(__sync_xor_and_fetch),
1016
1017    BUILTIN_ROW(__sync_val_compare_and_swap),
1018    BUILTIN_ROW(__sync_bool_compare_and_swap),
1019    BUILTIN_ROW(__sync_lock_test_and_set),
1020    BUILTIN_ROW(__sync_lock_release),
1021    BUILTIN_ROW(__sync_swap)
1022  };
1023#undef BUILTIN_ROW
1024
1025  // Determine the index of the size.
1026  unsigned SizeIndex;
1027  switch (Context.getTypeSizeInChars(ValType).getQuantity()) {
1028  case 1: SizeIndex = 0; break;
1029  case 2: SizeIndex = 1; break;
1030  case 4: SizeIndex = 2; break;
1031  case 8: SizeIndex = 3; break;
1032  case 16: SizeIndex = 4; break;
1033  default:
1034    Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size)
1035      << FirstArg->getType() << FirstArg->getSourceRange();
1036    return ExprError();
1037  }
1038
1039  // Each of these builtins has one pointer argument, followed by some number of
1040  // values (0, 1 or 2) followed by a potentially empty varags list of stuff
1041  // that we ignore.  Find out which row of BuiltinIndices to read from as well
1042  // as the number of fixed args.
1043  unsigned BuiltinID = FDecl->getBuiltinID();
1044  unsigned BuiltinIndex, NumFixed = 1;
1045  switch (BuiltinID) {
1046  default: llvm_unreachable("Unknown overloaded atomic builtin!");
1047  case Builtin::BI__sync_fetch_and_add:
1048  case Builtin::BI__sync_fetch_and_add_1:
1049  case Builtin::BI__sync_fetch_and_add_2:
1050  case Builtin::BI__sync_fetch_and_add_4:
1051  case Builtin::BI__sync_fetch_and_add_8:
1052  case Builtin::BI__sync_fetch_and_add_16:
1053    BuiltinIndex = 0;
1054    break;
1055
1056  case Builtin::BI__sync_fetch_and_sub:
1057  case Builtin::BI__sync_fetch_and_sub_1:
1058  case Builtin::BI__sync_fetch_and_sub_2:
1059  case Builtin::BI__sync_fetch_and_sub_4:
1060  case Builtin::BI__sync_fetch_and_sub_8:
1061  case Builtin::BI__sync_fetch_and_sub_16:
1062    BuiltinIndex = 1;
1063    break;
1064
1065  case Builtin::BI__sync_fetch_and_or:
1066  case Builtin::BI__sync_fetch_and_or_1:
1067  case Builtin::BI__sync_fetch_and_or_2:
1068  case Builtin::BI__sync_fetch_and_or_4:
1069  case Builtin::BI__sync_fetch_and_or_8:
1070  case Builtin::BI__sync_fetch_and_or_16:
1071    BuiltinIndex = 2;
1072    break;
1073
1074  case Builtin::BI__sync_fetch_and_and:
1075  case Builtin::BI__sync_fetch_and_and_1:
1076  case Builtin::BI__sync_fetch_and_and_2:
1077  case Builtin::BI__sync_fetch_and_and_4:
1078  case Builtin::BI__sync_fetch_and_and_8:
1079  case Builtin::BI__sync_fetch_and_and_16:
1080    BuiltinIndex = 3;
1081    break;
1082
1083  case Builtin::BI__sync_fetch_and_xor:
1084  case Builtin::BI__sync_fetch_and_xor_1:
1085  case Builtin::BI__sync_fetch_and_xor_2:
1086  case Builtin::BI__sync_fetch_and_xor_4:
1087  case Builtin::BI__sync_fetch_and_xor_8:
1088  case Builtin::BI__sync_fetch_and_xor_16:
1089    BuiltinIndex = 4;
1090    break;
1091
1092  case Builtin::BI__sync_add_and_fetch:
1093  case Builtin::BI__sync_add_and_fetch_1:
1094  case Builtin::BI__sync_add_and_fetch_2:
1095  case Builtin::BI__sync_add_and_fetch_4:
1096  case Builtin::BI__sync_add_and_fetch_8:
1097  case Builtin::BI__sync_add_and_fetch_16:
1098    BuiltinIndex = 5;
1099    break;
1100
1101  case Builtin::BI__sync_sub_and_fetch:
1102  case Builtin::BI__sync_sub_and_fetch_1:
1103  case Builtin::BI__sync_sub_and_fetch_2:
1104  case Builtin::BI__sync_sub_and_fetch_4:
1105  case Builtin::BI__sync_sub_and_fetch_8:
1106  case Builtin::BI__sync_sub_and_fetch_16:
1107    BuiltinIndex = 6;
1108    break;
1109
1110  case Builtin::BI__sync_and_and_fetch:
1111  case Builtin::BI__sync_and_and_fetch_1:
1112  case Builtin::BI__sync_and_and_fetch_2:
1113  case Builtin::BI__sync_and_and_fetch_4:
1114  case Builtin::BI__sync_and_and_fetch_8:
1115  case Builtin::BI__sync_and_and_fetch_16:
1116    BuiltinIndex = 7;
1117    break;
1118
1119  case Builtin::BI__sync_or_and_fetch:
1120  case Builtin::BI__sync_or_and_fetch_1:
1121  case Builtin::BI__sync_or_and_fetch_2:
1122  case Builtin::BI__sync_or_and_fetch_4:
1123  case Builtin::BI__sync_or_and_fetch_8:
1124  case Builtin::BI__sync_or_and_fetch_16:
1125    BuiltinIndex = 8;
1126    break;
1127
1128  case Builtin::BI__sync_xor_and_fetch:
1129  case Builtin::BI__sync_xor_and_fetch_1:
1130  case Builtin::BI__sync_xor_and_fetch_2:
1131  case Builtin::BI__sync_xor_and_fetch_4:
1132  case Builtin::BI__sync_xor_and_fetch_8:
1133  case Builtin::BI__sync_xor_and_fetch_16:
1134    BuiltinIndex = 9;
1135    break;
1136
1137  case Builtin::BI__sync_val_compare_and_swap:
1138  case Builtin::BI__sync_val_compare_and_swap_1:
1139  case Builtin::BI__sync_val_compare_and_swap_2:
1140  case Builtin::BI__sync_val_compare_and_swap_4:
1141  case Builtin::BI__sync_val_compare_and_swap_8:
1142  case Builtin::BI__sync_val_compare_and_swap_16:
1143    BuiltinIndex = 10;
1144    NumFixed = 2;
1145    break;
1146
1147  case Builtin::BI__sync_bool_compare_and_swap:
1148  case Builtin::BI__sync_bool_compare_and_swap_1:
1149  case Builtin::BI__sync_bool_compare_and_swap_2:
1150  case Builtin::BI__sync_bool_compare_and_swap_4:
1151  case Builtin::BI__sync_bool_compare_and_swap_8:
1152  case Builtin::BI__sync_bool_compare_and_swap_16:
1153    BuiltinIndex = 11;
1154    NumFixed = 2;
1155    ResultType = Context.BoolTy;
1156    break;
1157
1158  case Builtin::BI__sync_lock_test_and_set:
1159  case Builtin::BI__sync_lock_test_and_set_1:
1160  case Builtin::BI__sync_lock_test_and_set_2:
1161  case Builtin::BI__sync_lock_test_and_set_4:
1162  case Builtin::BI__sync_lock_test_and_set_8:
1163  case Builtin::BI__sync_lock_test_and_set_16:
1164    BuiltinIndex = 12;
1165    break;
1166
1167  case Builtin::BI__sync_lock_release:
1168  case Builtin::BI__sync_lock_release_1:
1169  case Builtin::BI__sync_lock_release_2:
1170  case Builtin::BI__sync_lock_release_4:
1171  case Builtin::BI__sync_lock_release_8:
1172  case Builtin::BI__sync_lock_release_16:
1173    BuiltinIndex = 13;
1174    NumFixed = 0;
1175    ResultType = Context.VoidTy;
1176    break;
1177
1178  case Builtin::BI__sync_swap:
1179  case Builtin::BI__sync_swap_1:
1180  case Builtin::BI__sync_swap_2:
1181  case Builtin::BI__sync_swap_4:
1182  case Builtin::BI__sync_swap_8:
1183  case Builtin::BI__sync_swap_16:
1184    BuiltinIndex = 14;
1185    break;
1186  }
1187
1188  // Now that we know how many fixed arguments we expect, first check that we
1189  // have at least that many.
1190  if (TheCall->getNumArgs() < 1+NumFixed) {
1191    Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
1192      << 0 << 1+NumFixed << TheCall->getNumArgs()
1193      << TheCall->getCallee()->getSourceRange();
1194    return ExprError();
1195  }
1196
1197  // Get the decl for the concrete builtin from this, we can tell what the
1198  // concrete integer type we should convert to is.
1199  unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex];
1200  const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID);
1201  FunctionDecl *NewBuiltinDecl;
1202  if (NewBuiltinID == BuiltinID)
1203    NewBuiltinDecl = FDecl;
1204  else {
1205    // Perform builtin lookup to avoid redeclaring it.
1206    DeclarationName DN(&Context.Idents.get(NewBuiltinName));
1207    LookupResult Res(*this, DN, DRE->getLocStart(), LookupOrdinaryName);
1208    LookupName(Res, TUScope, /*AllowBuiltinCreation=*/true);
1209    assert(Res.getFoundDecl());
1210    NewBuiltinDecl = dyn_cast<FunctionDecl>(Res.getFoundDecl());
1211    if (NewBuiltinDecl == 0)
1212      return ExprError();
1213  }
1214
1215  // The first argument --- the pointer --- has a fixed type; we
1216  // deduce the types of the rest of the arguments accordingly.  Walk
1217  // the remaining arguments, converting them to the deduced value type.
1218  for (unsigned i = 0; i != NumFixed; ++i) {
1219    ExprResult Arg = TheCall->getArg(i+1);
1220
1221    // GCC does an implicit conversion to the pointer or integer ValType.  This
1222    // can fail in some cases (1i -> int**), check for this error case now.
1223    // Initialize the argument.
1224    InitializedEntity Entity = InitializedEntity::InitializeParameter(Context,
1225                                                   ValType, /*consume*/ false);
1226    Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
1227    if (Arg.isInvalid())
1228      return ExprError();
1229
1230    // Okay, we have something that *can* be converted to the right type.  Check
1231    // to see if there is a potentially weird extension going on here.  This can
1232    // happen when you do an atomic operation on something like an char* and
1233    // pass in 42.  The 42 gets converted to char.  This is even more strange
1234    // for things like 45.123 -> char, etc.
1235    // FIXME: Do this check.
1236    TheCall->setArg(i+1, Arg.take());
1237  }
1238
1239  ASTContext& Context = this->getASTContext();
1240
1241  // Create a new DeclRefExpr to refer to the new decl.
1242  DeclRefExpr* NewDRE = DeclRefExpr::Create(
1243      Context,
1244      DRE->getQualifierLoc(),
1245      SourceLocation(),
1246      NewBuiltinDecl,
1247      /*enclosing*/ false,
1248      DRE->getLocation(),
1249      Context.BuiltinFnTy,
1250      DRE->getValueKind());
1251
1252  // Set the callee in the CallExpr.
1253  // FIXME: This loses syntactic information.
1254  QualType CalleePtrTy = Context.getPointerType(NewBuiltinDecl->getType());
1255  ExprResult PromotedCall = ImpCastExprToType(NewDRE, CalleePtrTy,
1256                                              CK_BuiltinFnToFnPtr);
1257  TheCall->setCallee(PromotedCall.take());
1258
1259  // Change the result type of the call to match the original value type. This
1260  // is arbitrary, but the codegen for these builtins ins design to handle it
1261  // gracefully.
1262  TheCall->setType(ResultType);
1263
1264  return TheCallResult;
1265}
1266
1267/// CheckObjCString - Checks that the argument to the builtin
1268/// CFString constructor is correct
1269/// Note: It might also make sense to do the UTF-16 conversion here (would
1270/// simplify the backend).
1271bool Sema::CheckObjCString(Expr *Arg) {
1272  Arg = Arg->IgnoreParenCasts();
1273  StringLiteral *Literal = dyn_cast<StringLiteral>(Arg);
1274
1275  if (!Literal || !Literal->isAscii()) {
1276    Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant)
1277      << Arg->getSourceRange();
1278    return true;
1279  }
1280
1281  if (Literal->containsNonAsciiOrNull()) {
1282    StringRef String = Literal->getString();
1283    unsigned NumBytes = String.size();
1284    SmallVector<UTF16, 128> ToBuf(NumBytes);
1285    const UTF8 *FromPtr = (const UTF8 *)String.data();
1286    UTF16 *ToPtr = &ToBuf[0];
1287
1288    ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes,
1289                                                 &ToPtr, ToPtr + NumBytes,
1290                                                 strictConversion);
1291    // Check for conversion failure.
1292    if (Result != conversionOK)
1293      Diag(Arg->getLocStart(),
1294           diag::warn_cfstring_truncated) << Arg->getSourceRange();
1295  }
1296  return false;
1297}
1298
1299/// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity.
1300/// Emit an error and return true on failure, return false on success.
1301bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) {
1302  Expr *Fn = TheCall->getCallee();
1303  if (TheCall->getNumArgs() > 2) {
1304    Diag(TheCall->getArg(2)->getLocStart(),
1305         diag::err_typecheck_call_too_many_args)
1306      << 0 /*function call*/ << 2 << TheCall->getNumArgs()
1307      << Fn->getSourceRange()
1308      << SourceRange(TheCall->getArg(2)->getLocStart(),
1309                     (*(TheCall->arg_end()-1))->getLocEnd());
1310    return true;
1311  }
1312
1313  if (TheCall->getNumArgs() < 2) {
1314    return Diag(TheCall->getLocEnd(),
1315      diag::err_typecheck_call_too_few_args_at_least)
1316      << 0 /*function call*/ << 2 << TheCall->getNumArgs();
1317  }
1318
1319  // Type-check the first argument normally.
1320  if (checkBuiltinArgument(*this, TheCall, 0))
1321    return true;
1322
1323  // Determine whether the current function is variadic or not.
1324  BlockScopeInfo *CurBlock = getCurBlock();
1325  bool isVariadic;
1326  if (CurBlock)
1327    isVariadic = CurBlock->TheDecl->isVariadic();
1328  else if (FunctionDecl *FD = getCurFunctionDecl())
1329    isVariadic = FD->isVariadic();
1330  else
1331    isVariadic = getCurMethodDecl()->isVariadic();
1332
1333  if (!isVariadic) {
1334    Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function);
1335    return true;
1336  }
1337
1338  // Verify that the second argument to the builtin is the last argument of the
1339  // current function or method.
1340  bool SecondArgIsLastNamedArgument = false;
1341  const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts();
1342
1343  if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) {
1344    if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) {
1345      // FIXME: This isn't correct for methods (results in bogus warning).
1346      // Get the last formal in the current function.
1347      const ParmVarDecl *LastArg;
1348      if (CurBlock)
1349        LastArg = *(CurBlock->TheDecl->param_end()-1);
1350      else if (FunctionDecl *FD = getCurFunctionDecl())
1351        LastArg = *(FD->param_end()-1);
1352      else
1353        LastArg = *(getCurMethodDecl()->param_end()-1);
1354      SecondArgIsLastNamedArgument = PV == LastArg;
1355    }
1356  }
1357
1358  if (!SecondArgIsLastNamedArgument)
1359    Diag(TheCall->getArg(1)->getLocStart(),
1360         diag::warn_second_parameter_of_va_start_not_last_named_argument);
1361  return false;
1362}
1363
1364/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and
1365/// friends.  This is declared to take (...), so we have to check everything.
1366bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) {
1367  if (TheCall->getNumArgs() < 2)
1368    return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
1369      << 0 << 2 << TheCall->getNumArgs()/*function call*/;
1370  if (TheCall->getNumArgs() > 2)
1371    return Diag(TheCall->getArg(2)->getLocStart(),
1372                diag::err_typecheck_call_too_many_args)
1373      << 0 /*function call*/ << 2 << TheCall->getNumArgs()
1374      << SourceRange(TheCall->getArg(2)->getLocStart(),
1375                     (*(TheCall->arg_end()-1))->getLocEnd());
1376
1377  ExprResult OrigArg0 = TheCall->getArg(0);
1378  ExprResult OrigArg1 = TheCall->getArg(1);
1379
1380  // Do standard promotions between the two arguments, returning their common
1381  // type.
1382  QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false);
1383  if (OrigArg0.isInvalid() || OrigArg1.isInvalid())
1384    return true;
1385
1386  // Make sure any conversions are pushed back into the call; this is
1387  // type safe since unordered compare builtins are declared as "_Bool
1388  // foo(...)".
1389  TheCall->setArg(0, OrigArg0.get());
1390  TheCall->setArg(1, OrigArg1.get());
1391
1392  if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent())
1393    return false;
1394
1395  // If the common type isn't a real floating type, then the arguments were
1396  // invalid for this operation.
1397  if (Res.isNull() || !Res->isRealFloatingType())
1398    return Diag(OrigArg0.get()->getLocStart(),
1399                diag::err_typecheck_call_invalid_ordered_compare)
1400      << OrigArg0.get()->getType() << OrigArg1.get()->getType()
1401      << SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd());
1402
1403  return false;
1404}
1405
1406/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like
1407/// __builtin_isnan and friends.  This is declared to take (...), so we have
1408/// to check everything. We expect the last argument to be a floating point
1409/// value.
1410bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) {
1411  if (TheCall->getNumArgs() < NumArgs)
1412    return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
1413      << 0 << NumArgs << TheCall->getNumArgs()/*function call*/;
1414  if (TheCall->getNumArgs() > NumArgs)
1415    return Diag(TheCall->getArg(NumArgs)->getLocStart(),
1416                diag::err_typecheck_call_too_many_args)
1417      << 0 /*function call*/ << NumArgs << TheCall->getNumArgs()
1418      << SourceRange(TheCall->getArg(NumArgs)->getLocStart(),
1419                     (*(TheCall->arg_end()-1))->getLocEnd());
1420
1421  Expr *OrigArg = TheCall->getArg(NumArgs-1);
1422
1423  if (OrigArg->isTypeDependent())
1424    return false;
1425
1426  // This operation requires a non-_Complex floating-point number.
1427  if (!OrigArg->getType()->isRealFloatingType())
1428    return Diag(OrigArg->getLocStart(),
1429                diag::err_typecheck_call_invalid_unary_fp)
1430      << OrigArg->getType() << OrigArg->getSourceRange();
1431
1432  // If this is an implicit conversion from float -> double, remove it.
1433  if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) {
1434    Expr *CastArg = Cast->getSubExpr();
1435    if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) {
1436      assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) &&
1437             "promotion from float to double is the only expected cast here");
1438      Cast->setSubExpr(0);
1439      TheCall->setArg(NumArgs-1, CastArg);
1440    }
1441  }
1442
1443  return false;
1444}
1445
1446/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector.
1447// This is declared to take (...), so we have to check everything.
1448ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) {
1449  if (TheCall->getNumArgs() < 2)
1450    return ExprError(Diag(TheCall->getLocEnd(),
1451                          diag::err_typecheck_call_too_few_args_at_least)
1452      << 0 /*function call*/ << 2 << TheCall->getNumArgs()
1453      << TheCall->getSourceRange());
1454
1455  // Determine which of the following types of shufflevector we're checking:
1456  // 1) unary, vector mask: (lhs, mask)
1457  // 2) binary, vector mask: (lhs, rhs, mask)
1458  // 3) binary, scalar mask: (lhs, rhs, index, ..., index)
1459  QualType resType = TheCall->getArg(0)->getType();
1460  unsigned numElements = 0;
1461
1462  if (!TheCall->getArg(0)->isTypeDependent() &&
1463      !TheCall->getArg(1)->isTypeDependent()) {
1464    QualType LHSType = TheCall->getArg(0)->getType();
1465    QualType RHSType = TheCall->getArg(1)->getType();
1466
1467    if (!LHSType->isVectorType() || !RHSType->isVectorType()) {
1468      Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector)
1469        << SourceRange(TheCall->getArg(0)->getLocStart(),
1470                       TheCall->getArg(1)->getLocEnd());
1471      return ExprError();
1472    }
1473
1474    numElements = LHSType->getAs<VectorType>()->getNumElements();
1475    unsigned numResElements = TheCall->getNumArgs() - 2;
1476
1477    // Check to see if we have a call with 2 vector arguments, the unary shuffle
1478    // with mask.  If so, verify that RHS is an integer vector type with the
1479    // same number of elts as lhs.
1480    if (TheCall->getNumArgs() == 2) {
1481      if (!RHSType->hasIntegerRepresentation() ||
1482          RHSType->getAs<VectorType>()->getNumElements() != numElements)
1483        Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector)
1484          << SourceRange(TheCall->getArg(1)->getLocStart(),
1485                         TheCall->getArg(1)->getLocEnd());
1486      numResElements = numElements;
1487    }
1488    else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) {
1489      Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector)
1490        << SourceRange(TheCall->getArg(0)->getLocStart(),
1491                       TheCall->getArg(1)->getLocEnd());
1492      return ExprError();
1493    } else if (numElements != numResElements) {
1494      QualType eltType = LHSType->getAs<VectorType>()->getElementType();
1495      resType = Context.getVectorType(eltType, numResElements,
1496                                      VectorType::GenericVector);
1497    }
1498  }
1499
1500  for (unsigned i = 2; i < TheCall->getNumArgs(); i++) {
1501    if (TheCall->getArg(i)->isTypeDependent() ||
1502        TheCall->getArg(i)->isValueDependent())
1503      continue;
1504
1505    llvm::APSInt Result(32);
1506    if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context))
1507      return ExprError(Diag(TheCall->getLocStart(),
1508                  diag::err_shufflevector_nonconstant_argument)
1509                << TheCall->getArg(i)->getSourceRange());
1510
1511    if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2)
1512      return ExprError(Diag(TheCall->getLocStart(),
1513                  diag::err_shufflevector_argument_too_large)
1514               << TheCall->getArg(i)->getSourceRange());
1515  }
1516
1517  SmallVector<Expr*, 32> exprs;
1518
1519  for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) {
1520    exprs.push_back(TheCall->getArg(i));
1521    TheCall->setArg(i, 0);
1522  }
1523
1524  return Owned(new (Context) ShuffleVectorExpr(Context, exprs, resType,
1525                                            TheCall->getCallee()->getLocStart(),
1526                                            TheCall->getRParenLoc()));
1527}
1528
1529/// SemaBuiltinPrefetch - Handle __builtin_prefetch.
1530// This is declared to take (const void*, ...) and can take two
1531// optional constant int args.
1532bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) {
1533  unsigned NumArgs = TheCall->getNumArgs();
1534
1535  if (NumArgs > 3)
1536    return Diag(TheCall->getLocEnd(),
1537             diag::err_typecheck_call_too_many_args_at_most)
1538             << 0 /*function call*/ << 3 << NumArgs
1539             << TheCall->getSourceRange();
1540
1541  // Argument 0 is checked for us and the remaining arguments must be
1542  // constant integers.
1543  for (unsigned i = 1; i != NumArgs; ++i) {
1544    Expr *Arg = TheCall->getArg(i);
1545
1546    // We can't check the value of a dependent argument.
1547    if (Arg->isTypeDependent() || Arg->isValueDependent())
1548      continue;
1549
1550    llvm::APSInt Result;
1551    if (SemaBuiltinConstantArg(TheCall, i, Result))
1552      return true;
1553
1554    // FIXME: gcc issues a warning and rewrites these to 0. These
1555    // seems especially odd for the third argument since the default
1556    // is 3.
1557    if (i == 1) {
1558      if (Result.getLimitedValue() > 1)
1559        return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
1560             << "0" << "1" << Arg->getSourceRange();
1561    } else {
1562      if (Result.getLimitedValue() > 3)
1563        return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
1564            << "0" << "3" << Arg->getSourceRange();
1565    }
1566  }
1567
1568  return false;
1569}
1570
1571/// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr
1572/// TheCall is a constant expression.
1573bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum,
1574                                  llvm::APSInt &Result) {
1575  Expr *Arg = TheCall->getArg(ArgNum);
1576  DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
1577  FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
1578
1579  if (Arg->isTypeDependent() || Arg->isValueDependent()) return false;
1580
1581  if (!Arg->isIntegerConstantExpr(Result, Context))
1582    return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type)
1583                << FDecl->getDeclName() <<  Arg->getSourceRange();
1584
1585  return false;
1586}
1587
1588/// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr,
1589/// int type). This simply type checks that type is one of the defined
1590/// constants (0-3).
1591// For compatibility check 0-3, llvm only handles 0 and 2.
1592bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) {
1593  llvm::APSInt Result;
1594
1595  // We can't check the value of a dependent argument.
1596  if (TheCall->getArg(1)->isTypeDependent() ||
1597      TheCall->getArg(1)->isValueDependent())
1598    return false;
1599
1600  // Check constant-ness first.
1601  if (SemaBuiltinConstantArg(TheCall, 1, Result))
1602    return true;
1603
1604  Expr *Arg = TheCall->getArg(1);
1605  if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) {
1606    return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
1607             << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
1608  }
1609
1610  return false;
1611}
1612
1613/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val).
1614/// This checks that val is a constant 1.
1615bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) {
1616  Expr *Arg = TheCall->getArg(1);
1617  llvm::APSInt Result;
1618
1619  // TODO: This is less than ideal. Overload this to take a value.
1620  if (SemaBuiltinConstantArg(TheCall, 1, Result))
1621    return true;
1622
1623  if (Result != 1)
1624    return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val)
1625             << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
1626
1627  return false;
1628}
1629
1630// Determine if an expression is a string literal or constant string.
1631// If this function returns false on the arguments to a function expecting a
1632// format string, we will usually need to emit a warning.
1633// True string literals are then checked by CheckFormatString.
1634Sema::StringLiteralCheckType
1635Sema::checkFormatStringExpr(const Expr *E, Expr **Args,
1636                            unsigned NumArgs, bool HasVAListArg,
1637                            unsigned format_idx, unsigned firstDataArg,
1638                            FormatStringType Type, VariadicCallType CallType,
1639                            bool inFunctionCall) {
1640 tryAgain:
1641  if (E->isTypeDependent() || E->isValueDependent())
1642    return SLCT_NotALiteral;
1643
1644  E = E->IgnoreParenCasts();
1645
1646  if (E->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull))
1647    // Technically -Wformat-nonliteral does not warn about this case.
1648    // The behavior of printf and friends in this case is implementation
1649    // dependent.  Ideally if the format string cannot be null then
1650    // it should have a 'nonnull' attribute in the function prototype.
1651    return SLCT_CheckedLiteral;
1652
1653  switch (E->getStmtClass()) {
1654  case Stmt::BinaryConditionalOperatorClass:
1655  case Stmt::ConditionalOperatorClass: {
1656    // The expression is a literal if both sub-expressions were, and it was
1657    // completely checked only if both sub-expressions were checked.
1658    const AbstractConditionalOperator *C =
1659        cast<AbstractConditionalOperator>(E);
1660    StringLiteralCheckType Left =
1661        checkFormatStringExpr(C->getTrueExpr(), Args, NumArgs,
1662                              HasVAListArg, format_idx, firstDataArg,
1663                              Type, CallType, inFunctionCall);
1664    if (Left == SLCT_NotALiteral)
1665      return SLCT_NotALiteral;
1666    StringLiteralCheckType Right =
1667        checkFormatStringExpr(C->getFalseExpr(), Args, NumArgs,
1668                              HasVAListArg, format_idx, firstDataArg,
1669                              Type, CallType, inFunctionCall);
1670    return Left < Right ? Left : Right;
1671  }
1672
1673  case Stmt::ImplicitCastExprClass: {
1674    E = cast<ImplicitCastExpr>(E)->getSubExpr();
1675    goto tryAgain;
1676  }
1677
1678  case Stmt::OpaqueValueExprClass:
1679    if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) {
1680      E = src;
1681      goto tryAgain;
1682    }
1683    return SLCT_NotALiteral;
1684
1685  case Stmt::PredefinedExprClass:
1686    // While __func__, etc., are technically not string literals, they
1687    // cannot contain format specifiers and thus are not a security
1688    // liability.
1689    return SLCT_UncheckedLiteral;
1690
1691  case Stmt::DeclRefExprClass: {
1692    const DeclRefExpr *DR = cast<DeclRefExpr>(E);
1693
1694    // As an exception, do not flag errors for variables binding to
1695    // const string literals.
1696    if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
1697      bool isConstant = false;
1698      QualType T = DR->getType();
1699
1700      if (const ArrayType *AT = Context.getAsArrayType(T)) {
1701        isConstant = AT->getElementType().isConstant(Context);
1702      } else if (const PointerType *PT = T->getAs<PointerType>()) {
1703        isConstant = T.isConstant(Context) &&
1704                     PT->getPointeeType().isConstant(Context);
1705      } else if (T->isObjCObjectPointerType()) {
1706        // In ObjC, there is usually no "const ObjectPointer" type,
1707        // so don't check if the pointee type is constant.
1708        isConstant = T.isConstant(Context);
1709      }
1710
1711      if (isConstant) {
1712        if (const Expr *Init = VD->getAnyInitializer()) {
1713          // Look through initializers like const char c[] = { "foo" }
1714          if (const InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) {
1715            if (InitList->isStringLiteralInit())
1716              Init = InitList->getInit(0)->IgnoreParenImpCasts();
1717          }
1718          return checkFormatStringExpr(Init, Args, NumArgs,
1719                                       HasVAListArg, format_idx,
1720                                       firstDataArg, Type, CallType,
1721                                       /*inFunctionCall*/false);
1722        }
1723      }
1724
1725      // For vprintf* functions (i.e., HasVAListArg==true), we add a
1726      // special check to see if the format string is a function parameter
1727      // of the function calling the printf function.  If the function
1728      // has an attribute indicating it is a printf-like function, then we
1729      // should suppress warnings concerning non-literals being used in a call
1730      // to a vprintf function.  For example:
1731      //
1732      // void
1733      // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){
1734      //      va_list ap;
1735      //      va_start(ap, fmt);
1736      //      vprintf(fmt, ap);  // Do NOT emit a warning about "fmt".
1737      //      ...
1738      //
1739      if (HasVAListArg) {
1740        if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(VD)) {
1741          if (const NamedDecl *ND = dyn_cast<NamedDecl>(PV->getDeclContext())) {
1742            int PVIndex = PV->getFunctionScopeIndex() + 1;
1743            for (specific_attr_iterator<FormatAttr>
1744                 i = ND->specific_attr_begin<FormatAttr>(),
1745                 e = ND->specific_attr_end<FormatAttr>(); i != e ; ++i) {
1746              FormatAttr *PVFormat = *i;
1747              // adjust for implicit parameter
1748              if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
1749                if (MD->isInstance())
1750                  ++PVIndex;
1751              // We also check if the formats are compatible.
1752              // We can't pass a 'scanf' string to a 'printf' function.
1753              if (PVIndex == PVFormat->getFormatIdx() &&
1754                  Type == GetFormatStringType(PVFormat))
1755                return SLCT_UncheckedLiteral;
1756            }
1757          }
1758        }
1759      }
1760    }
1761
1762    return SLCT_NotALiteral;
1763  }
1764
1765  case Stmt::CallExprClass:
1766  case Stmt::CXXMemberCallExprClass: {
1767    const CallExpr *CE = cast<CallExpr>(E);
1768    if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) {
1769      if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) {
1770        unsigned ArgIndex = FA->getFormatIdx();
1771        if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
1772          if (MD->isInstance())
1773            --ArgIndex;
1774        const Expr *Arg = CE->getArg(ArgIndex - 1);
1775
1776        return checkFormatStringExpr(Arg, Args, NumArgs,
1777                                     HasVAListArg, format_idx, firstDataArg,
1778                                     Type, CallType, inFunctionCall);
1779      } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
1780        unsigned BuiltinID = FD->getBuiltinID();
1781        if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString ||
1782            BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) {
1783          const Expr *Arg = CE->getArg(0);
1784          return checkFormatStringExpr(Arg, Args, NumArgs,
1785                                       HasVAListArg, format_idx,
1786                                       firstDataArg, Type, CallType,
1787                                       inFunctionCall);
1788        }
1789      }
1790    }
1791
1792    return SLCT_NotALiteral;
1793  }
1794  case Stmt::ObjCStringLiteralClass:
1795  case Stmt::StringLiteralClass: {
1796    const StringLiteral *StrE = NULL;
1797
1798    if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E))
1799      StrE = ObjCFExpr->getString();
1800    else
1801      StrE = cast<StringLiteral>(E);
1802
1803    if (StrE) {
1804      CheckFormatString(StrE, E, Args, NumArgs, HasVAListArg, format_idx,
1805                        firstDataArg, Type, inFunctionCall, CallType);
1806      return SLCT_CheckedLiteral;
1807    }
1808
1809    return SLCT_NotALiteral;
1810  }
1811
1812  default:
1813    return SLCT_NotALiteral;
1814  }
1815}
1816
1817void
1818Sema::CheckNonNullArguments(const NonNullAttr *NonNull,
1819                            const Expr * const *ExprArgs,
1820                            SourceLocation CallSiteLoc) {
1821  for (NonNullAttr::args_iterator i = NonNull->args_begin(),
1822                                  e = NonNull->args_end();
1823       i != e; ++i) {
1824    const Expr *ArgExpr = ExprArgs[*i];
1825    if (ArgExpr->isNullPointerConstant(Context,
1826                                       Expr::NPC_ValueDependentIsNotNull))
1827      Diag(CallSiteLoc, diag::warn_null_arg) << ArgExpr->getSourceRange();
1828  }
1829}
1830
1831Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) {
1832  return llvm::StringSwitch<FormatStringType>(Format->getType())
1833  .Case("scanf", FST_Scanf)
1834  .Cases("printf", "printf0", FST_Printf)
1835  .Cases("NSString", "CFString", FST_NSString)
1836  .Case("strftime", FST_Strftime)
1837  .Case("strfmon", FST_Strfmon)
1838  .Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf)
1839  .Default(FST_Unknown);
1840}
1841
1842/// CheckFormatArguments - Check calls to printf and scanf (and similar
1843/// functions) for correct use of format strings.
1844/// Returns true if a format string has been fully checked.
1845bool Sema::CheckFormatArguments(const FormatAttr *Format, Expr **Args,
1846                                unsigned NumArgs, bool IsCXXMember,
1847                                VariadicCallType CallType,
1848                                SourceLocation Loc, SourceRange Range) {
1849  FormatStringInfo FSI;
1850  if (getFormatStringInfo(Format, IsCXXMember, &FSI))
1851    return CheckFormatArguments(Args, NumArgs, FSI.HasVAListArg, FSI.FormatIdx,
1852                                FSI.FirstDataArg, GetFormatStringType(Format),
1853                                CallType, Loc, Range);
1854  return false;
1855}
1856
1857bool Sema::CheckFormatArguments(Expr **Args, unsigned NumArgs,
1858                                bool HasVAListArg, unsigned format_idx,
1859                                unsigned firstDataArg, FormatStringType Type,
1860                                VariadicCallType CallType,
1861                                SourceLocation Loc, SourceRange Range) {
1862  // CHECK: printf/scanf-like function is called with no format string.
1863  if (format_idx >= NumArgs) {
1864    Diag(Loc, diag::warn_missing_format_string) << Range;
1865    return false;
1866  }
1867
1868  const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts();
1869
1870  // CHECK: format string is not a string literal.
1871  //
1872  // Dynamically generated format strings are difficult to
1873  // automatically vet at compile time.  Requiring that format strings
1874  // are string literals: (1) permits the checking of format strings by
1875  // the compiler and thereby (2) can practically remove the source of
1876  // many format string exploits.
1877
1878  // Format string can be either ObjC string (e.g. @"%d") or
1879  // C string (e.g. "%d")
1880  // ObjC string uses the same format specifiers as C string, so we can use
1881  // the same format string checking logic for both ObjC and C strings.
1882  StringLiteralCheckType CT =
1883      checkFormatStringExpr(OrigFormatExpr, Args, NumArgs, HasVAListArg,
1884                            format_idx, firstDataArg, Type, CallType);
1885  if (CT != SLCT_NotALiteral)
1886    // Literal format string found, check done!
1887    return CT == SLCT_CheckedLiteral;
1888
1889  // Strftime is particular as it always uses a single 'time' argument,
1890  // so it is safe to pass a non-literal string.
1891  if (Type == FST_Strftime)
1892    return false;
1893
1894  // Do not emit diag when the string param is a macro expansion and the
1895  // format is either NSString or CFString. This is a hack to prevent
1896  // diag when using the NSLocalizedString and CFCopyLocalizedString macros
1897  // which are usually used in place of NS and CF string literals.
1898  if (Type == FST_NSString &&
1899      SourceMgr.isInSystemMacro(Args[format_idx]->getLocStart()))
1900    return false;
1901
1902  // If there are no arguments specified, warn with -Wformat-security, otherwise
1903  // warn only with -Wformat-nonliteral.
1904  if (NumArgs == format_idx+1)
1905    Diag(Args[format_idx]->getLocStart(),
1906         diag::warn_format_nonliteral_noargs)
1907      << OrigFormatExpr->getSourceRange();
1908  else
1909    Diag(Args[format_idx]->getLocStart(),
1910         diag::warn_format_nonliteral)
1911           << OrigFormatExpr->getSourceRange();
1912  return false;
1913}
1914
1915namespace {
1916class CheckFormatHandler : public analyze_format_string::FormatStringHandler {
1917protected:
1918  Sema &S;
1919  const StringLiteral *FExpr;
1920  const Expr *OrigFormatExpr;
1921  const unsigned FirstDataArg;
1922  const unsigned NumDataArgs;
1923  const char *Beg; // Start of format string.
1924  const bool HasVAListArg;
1925  const Expr * const *Args;
1926  const unsigned NumArgs;
1927  unsigned FormatIdx;
1928  llvm::BitVector CoveredArgs;
1929  bool usesPositionalArgs;
1930  bool atFirstArg;
1931  bool inFunctionCall;
1932  Sema::VariadicCallType CallType;
1933public:
1934  CheckFormatHandler(Sema &s, const StringLiteral *fexpr,
1935                     const Expr *origFormatExpr, unsigned firstDataArg,
1936                     unsigned numDataArgs, const char *beg, bool hasVAListArg,
1937                     Expr **args, unsigned numArgs,
1938                     unsigned formatIdx, bool inFunctionCall,
1939                     Sema::VariadicCallType callType)
1940    : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr),
1941      FirstDataArg(firstDataArg), NumDataArgs(numDataArgs),
1942      Beg(beg), HasVAListArg(hasVAListArg),
1943      Args(args), NumArgs(numArgs), FormatIdx(formatIdx),
1944      usesPositionalArgs(false), atFirstArg(true),
1945      inFunctionCall(inFunctionCall), CallType(callType) {
1946        CoveredArgs.resize(numDataArgs);
1947        CoveredArgs.reset();
1948      }
1949
1950  void DoneProcessing();
1951
1952  void HandleIncompleteSpecifier(const char *startSpecifier,
1953                                 unsigned specifierLen);
1954
1955  void HandleInvalidLengthModifier(
1956      const analyze_format_string::FormatSpecifier &FS,
1957      const analyze_format_string::ConversionSpecifier &CS,
1958      const char *startSpecifier, unsigned specifierLen, unsigned DiagID);
1959
1960  void HandleNonStandardLengthModifier(
1961      const analyze_format_string::FormatSpecifier &FS,
1962      const char *startSpecifier, unsigned specifierLen);
1963
1964  void HandleNonStandardConversionSpecifier(
1965      const analyze_format_string::ConversionSpecifier &CS,
1966      const char *startSpecifier, unsigned specifierLen);
1967
1968  virtual void HandlePosition(const char *startPos, unsigned posLen);
1969
1970  virtual void HandleInvalidPosition(const char *startSpecifier,
1971                                     unsigned specifierLen,
1972                                     analyze_format_string::PositionContext p);
1973
1974  virtual void HandleZeroPosition(const char *startPos, unsigned posLen);
1975
1976  void HandleNullChar(const char *nullCharacter);
1977
1978  template <typename Range>
1979  static void EmitFormatDiagnostic(Sema &S, bool inFunctionCall,
1980                                   const Expr *ArgumentExpr,
1981                                   PartialDiagnostic PDiag,
1982                                   SourceLocation StringLoc,
1983                                   bool IsStringLocation, Range StringRange,
1984                            ArrayRef<FixItHint> Fixit = ArrayRef<FixItHint>());
1985
1986protected:
1987  bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc,
1988                                        const char *startSpec,
1989                                        unsigned specifierLen,
1990                                        const char *csStart, unsigned csLen);
1991
1992  void HandlePositionalNonpositionalArgs(SourceLocation Loc,
1993                                         const char *startSpec,
1994                                         unsigned specifierLen);
1995
1996  SourceRange getFormatStringRange();
1997  CharSourceRange getSpecifierRange(const char *startSpecifier,
1998                                    unsigned specifierLen);
1999  SourceLocation getLocationOfByte(const char *x);
2000
2001  const Expr *getDataArg(unsigned i) const;
2002
2003  bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS,
2004                    const analyze_format_string::ConversionSpecifier &CS,
2005                    const char *startSpecifier, unsigned specifierLen,
2006                    unsigned argIndex);
2007
2008  template <typename Range>
2009  void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc,
2010                            bool IsStringLocation, Range StringRange,
2011                            ArrayRef<FixItHint> Fixit = ArrayRef<FixItHint>());
2012
2013  void CheckPositionalAndNonpositionalArgs(
2014      const analyze_format_string::FormatSpecifier *FS);
2015};
2016}
2017
2018SourceRange CheckFormatHandler::getFormatStringRange() {
2019  return OrigFormatExpr->getSourceRange();
2020}
2021
2022CharSourceRange CheckFormatHandler::
2023getSpecifierRange(const char *startSpecifier, unsigned specifierLen) {
2024  SourceLocation Start = getLocationOfByte(startSpecifier);
2025  SourceLocation End   = getLocationOfByte(startSpecifier + specifierLen - 1);
2026
2027  // Advance the end SourceLocation by one due to half-open ranges.
2028  End = End.getLocWithOffset(1);
2029
2030  return CharSourceRange::getCharRange(Start, End);
2031}
2032
2033SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) {
2034  return S.getLocationOfStringLiteralByte(FExpr, x - Beg);
2035}
2036
2037void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier,
2038                                                   unsigned specifierLen){
2039  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier),
2040                       getLocationOfByte(startSpecifier),
2041                       /*IsStringLocation*/true,
2042                       getSpecifierRange(startSpecifier, specifierLen));
2043}
2044
2045void CheckFormatHandler::HandleInvalidLengthModifier(
2046    const analyze_format_string::FormatSpecifier &FS,
2047    const analyze_format_string::ConversionSpecifier &CS,
2048    const char *startSpecifier, unsigned specifierLen, unsigned DiagID) {
2049  using namespace analyze_format_string;
2050
2051  const LengthModifier &LM = FS.getLengthModifier();
2052  CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength());
2053
2054  // See if we know how to fix this length modifier.
2055  llvm::Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier();
2056  if (FixedLM) {
2057    EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(),
2058                         getLocationOfByte(LM.getStart()),
2059                         /*IsStringLocation*/true,
2060                         getSpecifierRange(startSpecifier, specifierLen));
2061
2062    S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier)
2063      << FixedLM->toString()
2064      << FixItHint::CreateReplacement(LMRange, FixedLM->toString());
2065
2066  } else {
2067    FixItHint Hint;
2068    if (DiagID == diag::warn_format_nonsensical_length)
2069      Hint = FixItHint::CreateRemoval(LMRange);
2070
2071    EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(),
2072                         getLocationOfByte(LM.getStart()),
2073                         /*IsStringLocation*/true,
2074                         getSpecifierRange(startSpecifier, specifierLen),
2075                         Hint);
2076  }
2077}
2078
2079void CheckFormatHandler::HandleNonStandardLengthModifier(
2080    const analyze_format_string::FormatSpecifier &FS,
2081    const char *startSpecifier, unsigned specifierLen) {
2082  using namespace analyze_format_string;
2083
2084  const LengthModifier &LM = FS.getLengthModifier();
2085  CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength());
2086
2087  // See if we know how to fix this length modifier.
2088  llvm::Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier();
2089  if (FixedLM) {
2090    EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
2091                           << LM.toString() << 0,
2092                         getLocationOfByte(LM.getStart()),
2093                         /*IsStringLocation*/true,
2094                         getSpecifierRange(startSpecifier, specifierLen));
2095
2096    S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier)
2097      << FixedLM->toString()
2098      << FixItHint::CreateReplacement(LMRange, FixedLM->toString());
2099
2100  } else {
2101    EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
2102                           << LM.toString() << 0,
2103                         getLocationOfByte(LM.getStart()),
2104                         /*IsStringLocation*/true,
2105                         getSpecifierRange(startSpecifier, specifierLen));
2106  }
2107}
2108
2109void CheckFormatHandler::HandleNonStandardConversionSpecifier(
2110    const analyze_format_string::ConversionSpecifier &CS,
2111    const char *startSpecifier, unsigned specifierLen) {
2112  using namespace analyze_format_string;
2113
2114  // See if we know how to fix this conversion specifier.
2115  llvm::Optional<ConversionSpecifier> FixedCS = CS.getStandardSpecifier();
2116  if (FixedCS) {
2117    EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
2118                          << CS.toString() << /*conversion specifier*/1,
2119                         getLocationOfByte(CS.getStart()),
2120                         /*IsStringLocation*/true,
2121                         getSpecifierRange(startSpecifier, specifierLen));
2122
2123    CharSourceRange CSRange = getSpecifierRange(CS.getStart(), CS.getLength());
2124    S.Diag(getLocationOfByte(CS.getStart()), diag::note_format_fix_specifier)
2125      << FixedCS->toString()
2126      << FixItHint::CreateReplacement(CSRange, FixedCS->toString());
2127  } else {
2128    EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard)
2129                          << CS.toString() << /*conversion specifier*/1,
2130                         getLocationOfByte(CS.getStart()),
2131                         /*IsStringLocation*/true,
2132                         getSpecifierRange(startSpecifier, specifierLen));
2133  }
2134}
2135
2136void CheckFormatHandler::HandlePosition(const char *startPos,
2137                                        unsigned posLen) {
2138  EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg),
2139                               getLocationOfByte(startPos),
2140                               /*IsStringLocation*/true,
2141                               getSpecifierRange(startPos, posLen));
2142}
2143
2144void
2145CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen,
2146                                     analyze_format_string::PositionContext p) {
2147  EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier)
2148                         << (unsigned) p,
2149                       getLocationOfByte(startPos), /*IsStringLocation*/true,
2150                       getSpecifierRange(startPos, posLen));
2151}
2152
2153void CheckFormatHandler::HandleZeroPosition(const char *startPos,
2154                                            unsigned posLen) {
2155  EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier),
2156                               getLocationOfByte(startPos),
2157                               /*IsStringLocation*/true,
2158                               getSpecifierRange(startPos, posLen));
2159}
2160
2161void CheckFormatHandler::HandleNullChar(const char *nullCharacter) {
2162  if (!isa<ObjCStringLiteral>(OrigFormatExpr)) {
2163    // The presence of a null character is likely an error.
2164    EmitFormatDiagnostic(
2165      S.PDiag(diag::warn_printf_format_string_contains_null_char),
2166      getLocationOfByte(nullCharacter), /*IsStringLocation*/true,
2167      getFormatStringRange());
2168  }
2169}
2170
2171// Note that this may return NULL if there was an error parsing or building
2172// one of the argument expressions.
2173const Expr *CheckFormatHandler::getDataArg(unsigned i) const {
2174  return Args[FirstDataArg + i];
2175}
2176
2177void CheckFormatHandler::DoneProcessing() {
2178    // Does the number of data arguments exceed the number of
2179    // format conversions in the format string?
2180  if (!HasVAListArg) {
2181      // Find any arguments that weren't covered.
2182    CoveredArgs.flip();
2183    signed notCoveredArg = CoveredArgs.find_first();
2184    if (notCoveredArg >= 0) {
2185      assert((unsigned)notCoveredArg < NumDataArgs);
2186      if (const Expr *E = getDataArg((unsigned) notCoveredArg)) {
2187        SourceLocation Loc = E->getLocStart();
2188        if (!S.getSourceManager().isInSystemMacro(Loc)) {
2189          EmitFormatDiagnostic(S.PDiag(diag::warn_printf_data_arg_not_used),
2190                               Loc, /*IsStringLocation*/false,
2191                               getFormatStringRange());
2192        }
2193      }
2194    }
2195  }
2196}
2197
2198bool
2199CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex,
2200                                                     SourceLocation Loc,
2201                                                     const char *startSpec,
2202                                                     unsigned specifierLen,
2203                                                     const char *csStart,
2204                                                     unsigned csLen) {
2205
2206  bool keepGoing = true;
2207  if (argIndex < NumDataArgs) {
2208    // Consider the argument coverered, even though the specifier doesn't
2209    // make sense.
2210    CoveredArgs.set(argIndex);
2211  }
2212  else {
2213    // If argIndex exceeds the number of data arguments we
2214    // don't issue a warning because that is just a cascade of warnings (and
2215    // they may have intended '%%' anyway). We don't want to continue processing
2216    // the format string after this point, however, as we will like just get
2217    // gibberish when trying to match arguments.
2218    keepGoing = false;
2219  }
2220
2221  EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion)
2222                         << StringRef(csStart, csLen),
2223                       Loc, /*IsStringLocation*/true,
2224                       getSpecifierRange(startSpec, specifierLen));
2225
2226  return keepGoing;
2227}
2228
2229void
2230CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc,
2231                                                      const char *startSpec,
2232                                                      unsigned specifierLen) {
2233  EmitFormatDiagnostic(
2234    S.PDiag(diag::warn_format_mix_positional_nonpositional_args),
2235    Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen));
2236}
2237
2238bool
2239CheckFormatHandler::CheckNumArgs(
2240  const analyze_format_string::FormatSpecifier &FS,
2241  const analyze_format_string::ConversionSpecifier &CS,
2242  const char *startSpecifier, unsigned specifierLen, unsigned argIndex) {
2243
2244  if (argIndex >= NumDataArgs) {
2245    PartialDiagnostic PDiag = FS.usesPositionalArg()
2246      ? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args)
2247           << (argIndex+1) << NumDataArgs)
2248      : S.PDiag(diag::warn_printf_insufficient_data_args);
2249    EmitFormatDiagnostic(
2250      PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true,
2251      getSpecifierRange(startSpecifier, specifierLen));
2252    return false;
2253  }
2254  return true;
2255}
2256
2257template<typename Range>
2258void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag,
2259                                              SourceLocation Loc,
2260                                              bool IsStringLocation,
2261                                              Range StringRange,
2262                                              ArrayRef<FixItHint> FixIt) {
2263  EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag,
2264                       Loc, IsStringLocation, StringRange, FixIt);
2265}
2266
2267/// \brief If the format string is not within the funcion call, emit a note
2268/// so that the function call and string are in diagnostic messages.
2269///
2270/// \param InFunctionCall if true, the format string is within the function
2271/// call and only one diagnostic message will be produced.  Otherwise, an
2272/// extra note will be emitted pointing to location of the format string.
2273///
2274/// \param ArgumentExpr the expression that is passed as the format string
2275/// argument in the function call.  Used for getting locations when two
2276/// diagnostics are emitted.
2277///
2278/// \param PDiag the callee should already have provided any strings for the
2279/// diagnostic message.  This function only adds locations and fixits
2280/// to diagnostics.
2281///
2282/// \param Loc primary location for diagnostic.  If two diagnostics are
2283/// required, one will be at Loc and a new SourceLocation will be created for
2284/// the other one.
2285///
2286/// \param IsStringLocation if true, Loc points to the format string should be
2287/// used for the note.  Otherwise, Loc points to the argument list and will
2288/// be used with PDiag.
2289///
2290/// \param StringRange some or all of the string to highlight.  This is
2291/// templated so it can accept either a CharSourceRange or a SourceRange.
2292///
2293/// \param FixIt optional fix it hint for the format string.
2294template<typename Range>
2295void CheckFormatHandler::EmitFormatDiagnostic(Sema &S, bool InFunctionCall,
2296                                              const Expr *ArgumentExpr,
2297                                              PartialDiagnostic PDiag,
2298                                              SourceLocation Loc,
2299                                              bool IsStringLocation,
2300                                              Range StringRange,
2301                                              ArrayRef<FixItHint> FixIt) {
2302  if (InFunctionCall) {
2303    const Sema::SemaDiagnosticBuilder &D = S.Diag(Loc, PDiag);
2304    D << StringRange;
2305    for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end();
2306         I != E; ++I) {
2307      D << *I;
2308    }
2309  } else {
2310    S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag)
2311      << ArgumentExpr->getSourceRange();
2312
2313    const Sema::SemaDiagnosticBuilder &Note =
2314      S.Diag(IsStringLocation ? Loc : StringRange.getBegin(),
2315             diag::note_format_string_defined);
2316
2317    Note << StringRange;
2318    for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end();
2319         I != E; ++I) {
2320      Note << *I;
2321    }
2322  }
2323}
2324
2325//===--- CHECK: Printf format string checking ------------------------------===//
2326
2327namespace {
2328class CheckPrintfHandler : public CheckFormatHandler {
2329  bool ObjCContext;
2330public:
2331  CheckPrintfHandler(Sema &s, const StringLiteral *fexpr,
2332                     const Expr *origFormatExpr, unsigned firstDataArg,
2333                     unsigned numDataArgs, bool isObjC,
2334                     const char *beg, bool hasVAListArg,
2335                     Expr **Args, unsigned NumArgs,
2336                     unsigned formatIdx, bool inFunctionCall,
2337                     Sema::VariadicCallType CallType)
2338  : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
2339                       numDataArgs, beg, hasVAListArg, Args, NumArgs,
2340                       formatIdx, inFunctionCall, CallType), ObjCContext(isObjC)
2341  {}
2342
2343
2344  bool HandleInvalidPrintfConversionSpecifier(
2345                                      const analyze_printf::PrintfSpecifier &FS,
2346                                      const char *startSpecifier,
2347                                      unsigned specifierLen);
2348
2349  bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS,
2350                             const char *startSpecifier,
2351                             unsigned specifierLen);
2352  bool checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
2353                       const char *StartSpecifier,
2354                       unsigned SpecifierLen,
2355                       const Expr *E);
2356
2357  bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k,
2358                    const char *startSpecifier, unsigned specifierLen);
2359  void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS,
2360                           const analyze_printf::OptionalAmount &Amt,
2361                           unsigned type,
2362                           const char *startSpecifier, unsigned specifierLen);
2363  void HandleFlag(const analyze_printf::PrintfSpecifier &FS,
2364                  const analyze_printf::OptionalFlag &flag,
2365                  const char *startSpecifier, unsigned specifierLen);
2366  void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS,
2367                         const analyze_printf::OptionalFlag &ignoredFlag,
2368                         const analyze_printf::OptionalFlag &flag,
2369                         const char *startSpecifier, unsigned specifierLen);
2370  bool checkForCStrMembers(const analyze_printf::ArgType &AT,
2371                           const Expr *E, const CharSourceRange &CSR);
2372
2373};
2374}
2375
2376bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier(
2377                                      const analyze_printf::PrintfSpecifier &FS,
2378                                      const char *startSpecifier,
2379                                      unsigned specifierLen) {
2380  const analyze_printf::PrintfConversionSpecifier &CS =
2381    FS.getConversionSpecifier();
2382
2383  return HandleInvalidConversionSpecifier(FS.getArgIndex(),
2384                                          getLocationOfByte(CS.getStart()),
2385                                          startSpecifier, specifierLen,
2386                                          CS.getStart(), CS.getLength());
2387}
2388
2389bool CheckPrintfHandler::HandleAmount(
2390                               const analyze_format_string::OptionalAmount &Amt,
2391                               unsigned k, const char *startSpecifier,
2392                               unsigned specifierLen) {
2393
2394  if (Amt.hasDataArgument()) {
2395    if (!HasVAListArg) {
2396      unsigned argIndex = Amt.getArgIndex();
2397      if (argIndex >= NumDataArgs) {
2398        EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg)
2399                               << k,
2400                             getLocationOfByte(Amt.getStart()),
2401                             /*IsStringLocation*/true,
2402                             getSpecifierRange(startSpecifier, specifierLen));
2403        // Don't do any more checking.  We will just emit
2404        // spurious errors.
2405        return false;
2406      }
2407
2408      // Type check the data argument.  It should be an 'int'.
2409      // Although not in conformance with C99, we also allow the argument to be
2410      // an 'unsigned int' as that is a reasonably safe case.  GCC also
2411      // doesn't emit a warning for that case.
2412      CoveredArgs.set(argIndex);
2413      const Expr *Arg = getDataArg(argIndex);
2414      if (!Arg)
2415        return false;
2416
2417      QualType T = Arg->getType();
2418
2419      const analyze_printf::ArgType &AT = Amt.getArgType(S.Context);
2420      assert(AT.isValid());
2421
2422      if (!AT.matchesType(S.Context, T)) {
2423        EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type)
2424                               << k << AT.getRepresentativeTypeName(S.Context)
2425                               << T << Arg->getSourceRange(),
2426                             getLocationOfByte(Amt.getStart()),
2427                             /*IsStringLocation*/true,
2428                             getSpecifierRange(startSpecifier, specifierLen));
2429        // Don't do any more checking.  We will just emit
2430        // spurious errors.
2431        return false;
2432      }
2433    }
2434  }
2435  return true;
2436}
2437
2438void CheckPrintfHandler::HandleInvalidAmount(
2439                                      const analyze_printf::PrintfSpecifier &FS,
2440                                      const analyze_printf::OptionalAmount &Amt,
2441                                      unsigned type,
2442                                      const char *startSpecifier,
2443                                      unsigned specifierLen) {
2444  const analyze_printf::PrintfConversionSpecifier &CS =
2445    FS.getConversionSpecifier();
2446
2447  FixItHint fixit =
2448    Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant
2449      ? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(),
2450                                 Amt.getConstantLength()))
2451      : FixItHint();
2452
2453  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount)
2454                         << type << CS.toString(),
2455                       getLocationOfByte(Amt.getStart()),
2456                       /*IsStringLocation*/true,
2457                       getSpecifierRange(startSpecifier, specifierLen),
2458                       fixit);
2459}
2460
2461void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS,
2462                                    const analyze_printf::OptionalFlag &flag,
2463                                    const char *startSpecifier,
2464                                    unsigned specifierLen) {
2465  // Warn about pointless flag with a fixit removal.
2466  const analyze_printf::PrintfConversionSpecifier &CS =
2467    FS.getConversionSpecifier();
2468  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag)
2469                         << flag.toString() << CS.toString(),
2470                       getLocationOfByte(flag.getPosition()),
2471                       /*IsStringLocation*/true,
2472                       getSpecifierRange(startSpecifier, specifierLen),
2473                       FixItHint::CreateRemoval(
2474                         getSpecifierRange(flag.getPosition(), 1)));
2475}
2476
2477void CheckPrintfHandler::HandleIgnoredFlag(
2478                                const analyze_printf::PrintfSpecifier &FS,
2479                                const analyze_printf::OptionalFlag &ignoredFlag,
2480                                const analyze_printf::OptionalFlag &flag,
2481                                const char *startSpecifier,
2482                                unsigned specifierLen) {
2483  // Warn about ignored flag with a fixit removal.
2484  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag)
2485                         << ignoredFlag.toString() << flag.toString(),
2486                       getLocationOfByte(ignoredFlag.getPosition()),
2487                       /*IsStringLocation*/true,
2488                       getSpecifierRange(startSpecifier, specifierLen),
2489                       FixItHint::CreateRemoval(
2490                         getSpecifierRange(ignoredFlag.getPosition(), 1)));
2491}
2492
2493// Determines if the specified is a C++ class or struct containing
2494// a member with the specified name and kind (e.g. a CXXMethodDecl named
2495// "c_str()").
2496template<typename MemberKind>
2497static llvm::SmallPtrSet<MemberKind*, 1>
2498CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) {
2499  const RecordType *RT = Ty->getAs<RecordType>();
2500  llvm::SmallPtrSet<MemberKind*, 1> Results;
2501
2502  if (!RT)
2503    return Results;
2504  const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl());
2505  if (!RD)
2506    return Results;
2507
2508  LookupResult R(S, &S.PP.getIdentifierTable().get(Name), SourceLocation(),
2509                 Sema::LookupMemberName);
2510
2511  // We just need to include all members of the right kind turned up by the
2512  // filter, at this point.
2513  if (S.LookupQualifiedName(R, RT->getDecl()))
2514    for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) {
2515      NamedDecl *decl = (*I)->getUnderlyingDecl();
2516      if (MemberKind *FK = dyn_cast<MemberKind>(decl))
2517        Results.insert(FK);
2518    }
2519  return Results;
2520}
2521
2522// Check if a (w)string was passed when a (w)char* was needed, and offer a
2523// better diagnostic if so. AT is assumed to be valid.
2524// Returns true when a c_str() conversion method is found.
2525bool CheckPrintfHandler::checkForCStrMembers(
2526    const analyze_printf::ArgType &AT, const Expr *E,
2527    const CharSourceRange &CSR) {
2528  typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet;
2529
2530  MethodSet Results =
2531      CXXRecordMembersNamed<CXXMethodDecl>("c_str", S, E->getType());
2532
2533  for (MethodSet::iterator MI = Results.begin(), ME = Results.end();
2534       MI != ME; ++MI) {
2535    const CXXMethodDecl *Method = *MI;
2536    if (Method->getNumParams() == 0 &&
2537          AT.matchesType(S.Context, Method->getResultType())) {
2538      // FIXME: Suggest parens if the expression needs them.
2539      SourceLocation EndLoc =
2540          S.getPreprocessor().getLocForEndOfToken(E->getLocEnd());
2541      S.Diag(E->getLocStart(), diag::note_printf_c_str)
2542          << "c_str()"
2543          << FixItHint::CreateInsertion(EndLoc, ".c_str()");
2544      return true;
2545    }
2546  }
2547
2548  return false;
2549}
2550
2551bool
2552CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier
2553                                            &FS,
2554                                          const char *startSpecifier,
2555                                          unsigned specifierLen) {
2556
2557  using namespace analyze_format_string;
2558  using namespace analyze_printf;
2559  const PrintfConversionSpecifier &CS = FS.getConversionSpecifier();
2560
2561  if (FS.consumesDataArgument()) {
2562    if (atFirstArg) {
2563        atFirstArg = false;
2564        usesPositionalArgs = FS.usesPositionalArg();
2565    }
2566    else if (usesPositionalArgs != FS.usesPositionalArg()) {
2567      HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()),
2568                                        startSpecifier, specifierLen);
2569      return false;
2570    }
2571  }
2572
2573  // First check if the field width, precision, and conversion specifier
2574  // have matching data arguments.
2575  if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0,
2576                    startSpecifier, specifierLen)) {
2577    return false;
2578  }
2579
2580  if (!HandleAmount(FS.getPrecision(), /* precision */ 1,
2581                    startSpecifier, specifierLen)) {
2582    return false;
2583  }
2584
2585  if (!CS.consumesDataArgument()) {
2586    // FIXME: Technically specifying a precision or field width here
2587    // makes no sense.  Worth issuing a warning at some point.
2588    return true;
2589  }
2590
2591  // Consume the argument.
2592  unsigned argIndex = FS.getArgIndex();
2593  if (argIndex < NumDataArgs) {
2594    // The check to see if the argIndex is valid will come later.
2595    // We set the bit here because we may exit early from this
2596    // function if we encounter some other error.
2597    CoveredArgs.set(argIndex);
2598  }
2599
2600  // Check for using an Objective-C specific conversion specifier
2601  // in a non-ObjC literal.
2602  if (!ObjCContext && CS.isObjCArg()) {
2603    return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier,
2604                                                  specifierLen);
2605  }
2606
2607  // Check for invalid use of field width
2608  if (!FS.hasValidFieldWidth()) {
2609    HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0,
2610        startSpecifier, specifierLen);
2611  }
2612
2613  // Check for invalid use of precision
2614  if (!FS.hasValidPrecision()) {
2615    HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1,
2616        startSpecifier, specifierLen);
2617  }
2618
2619  // Check each flag does not conflict with any other component.
2620  if (!FS.hasValidThousandsGroupingPrefix())
2621    HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen);
2622  if (!FS.hasValidLeadingZeros())
2623    HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen);
2624  if (!FS.hasValidPlusPrefix())
2625    HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen);
2626  if (!FS.hasValidSpacePrefix())
2627    HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen);
2628  if (!FS.hasValidAlternativeForm())
2629    HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen);
2630  if (!FS.hasValidLeftJustified())
2631    HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen);
2632
2633  // Check that flags are not ignored by another flag
2634  if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+'
2635    HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(),
2636        startSpecifier, specifierLen);
2637  if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-'
2638    HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(),
2639            startSpecifier, specifierLen);
2640
2641  // Check the length modifier is valid with the given conversion specifier.
2642  if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo()))
2643    HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
2644                                diag::warn_format_nonsensical_length);
2645  else if (!FS.hasStandardLengthModifier())
2646    HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen);
2647  else if (!FS.hasStandardLengthConversionCombination())
2648    HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
2649                                diag::warn_format_non_standard_conversion_spec);
2650
2651  if (!FS.hasStandardConversionSpecifier(S.getLangOpts()))
2652    HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen);
2653
2654  // The remaining checks depend on the data arguments.
2655  if (HasVAListArg)
2656    return true;
2657
2658  if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
2659    return false;
2660
2661  const Expr *Arg = getDataArg(argIndex);
2662  if (!Arg)
2663    return true;
2664
2665  return checkFormatExpr(FS, startSpecifier, specifierLen, Arg);
2666}
2667
2668static bool requiresParensToAddCast(const Expr *E) {
2669  // FIXME: We should have a general way to reason about operator
2670  // precedence and whether parens are actually needed here.
2671  // Take care of a few common cases where they aren't.
2672  const Expr *Inside = E->IgnoreImpCasts();
2673  if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Inside))
2674    Inside = POE->getSyntacticForm()->IgnoreImpCasts();
2675
2676  switch (Inside->getStmtClass()) {
2677  case Stmt::ArraySubscriptExprClass:
2678  case Stmt::CallExprClass:
2679  case Stmt::DeclRefExprClass:
2680  case Stmt::MemberExprClass:
2681  case Stmt::ObjCIvarRefExprClass:
2682  case Stmt::ObjCMessageExprClass:
2683  case Stmt::ObjCPropertyRefExprClass:
2684  case Stmt::ParenExprClass:
2685  case Stmt::UnaryOperatorClass:
2686    return false;
2687  default:
2688    return true;
2689  }
2690}
2691
2692bool
2693CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
2694                                    const char *StartSpecifier,
2695                                    unsigned SpecifierLen,
2696                                    const Expr *E) {
2697  using namespace analyze_format_string;
2698  using namespace analyze_printf;
2699  // Now type check the data expression that matches the
2700  // format specifier.
2701  const analyze_printf::ArgType &AT = FS.getArgType(S.Context,
2702                                                    ObjCContext);
2703  if (!AT.isValid())
2704    return true;
2705
2706  QualType IntendedTy = E->getType();
2707  if (AT.matchesType(S.Context, IntendedTy))
2708    return true;
2709
2710  // Look through argument promotions for our error message's reported type.
2711  // This includes the integral and floating promotions, but excludes array
2712  // and function pointer decay; seeing that an argument intended to be a
2713  // string has type 'char [6]' is probably more confusing than 'char *'.
2714  if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
2715    if (ICE->getCastKind() == CK_IntegralCast ||
2716        ICE->getCastKind() == CK_FloatingCast) {
2717      E = ICE->getSubExpr();
2718      IntendedTy = E->getType();
2719
2720      // Check if we didn't match because of an implicit cast from a 'char'
2721      // or 'short' to an 'int'.  This is done because printf is a varargs
2722      // function.
2723      if (ICE->getType() == S.Context.IntTy ||
2724          ICE->getType() == S.Context.UnsignedIntTy) {
2725        // All further checking is done on the subexpression.
2726        if (AT.matchesType(S.Context, IntendedTy))
2727          return true;
2728      }
2729    }
2730  }
2731
2732  if (S.Context.getTargetInfo().getTriple().isOSDarwin()) {
2733    // Special-case some of Darwin's platform-independence types.
2734    if (const TypedefType *UserTy = IntendedTy->getAs<TypedefType>()) {
2735      StringRef Name = UserTy->getDecl()->getName();
2736      IntendedTy = llvm::StringSwitch<QualType>(Name)
2737        .Case("NSInteger", S.Context.LongTy)
2738        .Case("NSUInteger", S.Context.UnsignedLongTy)
2739        .Case("SInt32", S.Context.IntTy)
2740        .Case("UInt32", S.Context.UnsignedIntTy)
2741        .Default(IntendedTy);
2742    }
2743  }
2744
2745  // We may be able to offer a FixItHint if it is a supported type.
2746  PrintfSpecifier fixedFS = FS;
2747  bool success = fixedFS.fixType(IntendedTy, S.getLangOpts(),
2748                                 S.Context, ObjCContext);
2749
2750  if (success) {
2751    // Get the fix string from the fixed format specifier
2752    SmallString<16> buf;
2753    llvm::raw_svector_ostream os(buf);
2754    fixedFS.toString(os);
2755
2756    CharSourceRange SpecRange = getSpecifierRange(StartSpecifier, SpecifierLen);
2757
2758    if (IntendedTy != E->getType()) {
2759      // The canonical type for formatting this value is different from the
2760      // actual type of the expression. (This occurs, for example, with Darwin's
2761      // NSInteger on 32-bit platforms, where it is typedef'd as 'int', but
2762      // should be printed as 'long' for 64-bit compatibility.)
2763      // Rather than emitting a normal format/argument mismatch, we want to
2764      // add a cast to the recommended type (and correct the format string
2765      // if necessary).
2766      SmallString<16> CastBuf;
2767      llvm::raw_svector_ostream CastFix(CastBuf);
2768      CastFix << "(";
2769      IntendedTy.print(CastFix, S.Context.getPrintingPolicy());
2770      CastFix << ")";
2771
2772      SmallVector<FixItHint,4> Hints;
2773      if (!AT.matchesType(S.Context, IntendedTy))
2774        Hints.push_back(FixItHint::CreateReplacement(SpecRange, os.str()));
2775
2776      if (const CStyleCastExpr *CCast = dyn_cast<CStyleCastExpr>(E)) {
2777        // If there's already a cast present, just replace it.
2778        SourceRange CastRange(CCast->getLParenLoc(), CCast->getRParenLoc());
2779        Hints.push_back(FixItHint::CreateReplacement(CastRange, CastFix.str()));
2780
2781      } else if (!requiresParensToAddCast(E)) {
2782        // If the expression has high enough precedence,
2783        // just write the C-style cast.
2784        Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(),
2785                                                   CastFix.str()));
2786      } else {
2787        // Otherwise, add parens around the expression as well as the cast.
2788        CastFix << "(";
2789        Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(),
2790                                                   CastFix.str()));
2791
2792        SourceLocation After = S.PP.getLocForEndOfToken(E->getLocEnd());
2793        Hints.push_back(FixItHint::CreateInsertion(After, ")"));
2794      }
2795
2796      // We extract the name from the typedef because we don't want to show
2797      // the underlying type in the diagnostic.
2798      const TypedefType *UserTy = cast<TypedefType>(E->getType());
2799      StringRef Name = UserTy->getDecl()->getName();
2800
2801      // Finally, emit the diagnostic.
2802      EmitFormatDiagnostic(S.PDiag(diag::warn_format_argument_needs_cast)
2803                             << Name << IntendedTy
2804                             << E->getSourceRange(),
2805                           E->getLocStart(), /*IsStringLocation=*/false,
2806                           SpecRange, Hints);
2807    } else {
2808      EmitFormatDiagnostic(
2809        S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
2810          << AT.getRepresentativeTypeName(S.Context) << IntendedTy
2811          << E->getSourceRange(),
2812        E->getLocStart(),
2813        /*IsStringLocation*/false,
2814        SpecRange,
2815        FixItHint::CreateReplacement(SpecRange, os.str()));
2816    }
2817  } else {
2818    const CharSourceRange &CSR = getSpecifierRange(StartSpecifier,
2819                                                   SpecifierLen);
2820    // Since the warning for passing non-POD types to variadic functions
2821    // was deferred until now, we emit a warning for non-POD
2822    // arguments here.
2823    if (S.isValidVarArgType(E->getType()) == Sema::VAK_Invalid) {
2824      unsigned DiagKind;
2825      if (E->getType()->isObjCObjectType())
2826        DiagKind = diag::err_cannot_pass_objc_interface_to_vararg_format;
2827      else
2828        DiagKind = diag::warn_non_pod_vararg_with_format_string;
2829
2830      EmitFormatDiagnostic(
2831        S.PDiag(DiagKind)
2832          << S.getLangOpts().CPlusPlus0x
2833          << E->getType()
2834          << CallType
2835          << AT.getRepresentativeTypeName(S.Context)
2836          << CSR
2837          << E->getSourceRange(),
2838        E->getLocStart(), /*IsStringLocation*/false, CSR);
2839
2840      checkForCStrMembers(AT, E, CSR);
2841    } else
2842      EmitFormatDiagnostic(
2843        S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
2844          << AT.getRepresentativeTypeName(S.Context) << E->getType()
2845          << CSR
2846          << E->getSourceRange(),
2847        E->getLocStart(), /*IsStringLocation*/false, CSR);
2848  }
2849
2850  return true;
2851}
2852
2853//===--- CHECK: Scanf format string checking ------------------------------===//
2854
2855namespace {
2856class CheckScanfHandler : public CheckFormatHandler {
2857public:
2858  CheckScanfHandler(Sema &s, const StringLiteral *fexpr,
2859                    const Expr *origFormatExpr, unsigned firstDataArg,
2860                    unsigned numDataArgs, const char *beg, bool hasVAListArg,
2861                    Expr **Args, unsigned NumArgs,
2862                    unsigned formatIdx, bool inFunctionCall,
2863                    Sema::VariadicCallType CallType)
2864  : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
2865                       numDataArgs, beg, hasVAListArg,
2866                       Args, NumArgs, formatIdx, inFunctionCall, CallType)
2867  {}
2868
2869  bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS,
2870                            const char *startSpecifier,
2871                            unsigned specifierLen);
2872
2873  bool HandleInvalidScanfConversionSpecifier(
2874          const analyze_scanf::ScanfSpecifier &FS,
2875          const char *startSpecifier,
2876          unsigned specifierLen);
2877
2878  void HandleIncompleteScanList(const char *start, const char *end);
2879};
2880}
2881
2882void CheckScanfHandler::HandleIncompleteScanList(const char *start,
2883                                                 const char *end) {
2884  EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete),
2885                       getLocationOfByte(end), /*IsStringLocation*/true,
2886                       getSpecifierRange(start, end - start));
2887}
2888
2889bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier(
2890                                        const analyze_scanf::ScanfSpecifier &FS,
2891                                        const char *startSpecifier,
2892                                        unsigned specifierLen) {
2893
2894  const analyze_scanf::ScanfConversionSpecifier &CS =
2895    FS.getConversionSpecifier();
2896
2897  return HandleInvalidConversionSpecifier(FS.getArgIndex(),
2898                                          getLocationOfByte(CS.getStart()),
2899                                          startSpecifier, specifierLen,
2900                                          CS.getStart(), CS.getLength());
2901}
2902
2903bool CheckScanfHandler::HandleScanfSpecifier(
2904                                       const analyze_scanf::ScanfSpecifier &FS,
2905                                       const char *startSpecifier,
2906                                       unsigned specifierLen) {
2907
2908  using namespace analyze_scanf;
2909  using namespace analyze_format_string;
2910
2911  const ScanfConversionSpecifier &CS = FS.getConversionSpecifier();
2912
2913  // Handle case where '%' and '*' don't consume an argument.  These shouldn't
2914  // be used to decide if we are using positional arguments consistently.
2915  if (FS.consumesDataArgument()) {
2916    if (atFirstArg) {
2917      atFirstArg = false;
2918      usesPositionalArgs = FS.usesPositionalArg();
2919    }
2920    else if (usesPositionalArgs != FS.usesPositionalArg()) {
2921      HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()),
2922                                        startSpecifier, specifierLen);
2923      return false;
2924    }
2925  }
2926
2927  // Check if the field with is non-zero.
2928  const OptionalAmount &Amt = FS.getFieldWidth();
2929  if (Amt.getHowSpecified() == OptionalAmount::Constant) {
2930    if (Amt.getConstantAmount() == 0) {
2931      const CharSourceRange &R = getSpecifierRange(Amt.getStart(),
2932                                                   Amt.getConstantLength());
2933      EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width),
2934                           getLocationOfByte(Amt.getStart()),
2935                           /*IsStringLocation*/true, R,
2936                           FixItHint::CreateRemoval(R));
2937    }
2938  }
2939
2940  if (!FS.consumesDataArgument()) {
2941    // FIXME: Technically specifying a precision or field width here
2942    // makes no sense.  Worth issuing a warning at some point.
2943    return true;
2944  }
2945
2946  // Consume the argument.
2947  unsigned argIndex = FS.getArgIndex();
2948  if (argIndex < NumDataArgs) {
2949      // The check to see if the argIndex is valid will come later.
2950      // We set the bit here because we may exit early from this
2951      // function if we encounter some other error.
2952    CoveredArgs.set(argIndex);
2953  }
2954
2955  // Check the length modifier is valid with the given conversion specifier.
2956  if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo()))
2957    HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
2958                                diag::warn_format_nonsensical_length);
2959  else if (!FS.hasStandardLengthModifier())
2960    HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen);
2961  else if (!FS.hasStandardLengthConversionCombination())
2962    HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen,
2963                                diag::warn_format_non_standard_conversion_spec);
2964
2965  if (!FS.hasStandardConversionSpecifier(S.getLangOpts()))
2966    HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen);
2967
2968  // The remaining checks depend on the data arguments.
2969  if (HasVAListArg)
2970    return true;
2971
2972  if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
2973    return false;
2974
2975  // Check that the argument type matches the format specifier.
2976  const Expr *Ex = getDataArg(argIndex);
2977  if (!Ex)
2978    return true;
2979
2980  const analyze_format_string::ArgType &AT = FS.getArgType(S.Context);
2981  if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType())) {
2982    ScanfSpecifier fixedFS = FS;
2983    bool success = fixedFS.fixType(Ex->getType(), S.getLangOpts(),
2984                                   S.Context);
2985
2986    if (success) {
2987      // Get the fix string from the fixed format specifier.
2988      SmallString<128> buf;
2989      llvm::raw_svector_ostream os(buf);
2990      fixedFS.toString(os);
2991
2992      EmitFormatDiagnostic(
2993        S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
2994          << AT.getRepresentativeTypeName(S.Context) << Ex->getType()
2995          << Ex->getSourceRange(),
2996        Ex->getLocStart(),
2997        /*IsStringLocation*/false,
2998        getSpecifierRange(startSpecifier, specifierLen),
2999        FixItHint::CreateReplacement(
3000          getSpecifierRange(startSpecifier, specifierLen),
3001          os.str()));
3002    } else {
3003      EmitFormatDiagnostic(
3004        S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
3005          << AT.getRepresentativeTypeName(S.Context) << Ex->getType()
3006          << Ex->getSourceRange(),
3007        Ex->getLocStart(),
3008        /*IsStringLocation*/false,
3009        getSpecifierRange(startSpecifier, specifierLen));
3010    }
3011  }
3012
3013  return true;
3014}
3015
3016void Sema::CheckFormatString(const StringLiteral *FExpr,
3017                             const Expr *OrigFormatExpr,
3018                             Expr **Args, unsigned NumArgs,
3019                             bool HasVAListArg, unsigned format_idx,
3020                             unsigned firstDataArg, FormatStringType Type,
3021                             bool inFunctionCall, VariadicCallType CallType) {
3022
3023  // CHECK: is the format string a wide literal?
3024  if (!FExpr->isAscii() && !FExpr->isUTF8()) {
3025    CheckFormatHandler::EmitFormatDiagnostic(
3026      *this, inFunctionCall, Args[format_idx],
3027      PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(),
3028      /*IsStringLocation*/true, OrigFormatExpr->getSourceRange());
3029    return;
3030  }
3031
3032  // Str - The format string.  NOTE: this is NOT null-terminated!
3033  StringRef StrRef = FExpr->getString();
3034  const char *Str = StrRef.data();
3035  unsigned StrLen = StrRef.size();
3036  const unsigned numDataArgs = NumArgs - firstDataArg;
3037
3038  // CHECK: empty format string?
3039  if (StrLen == 0 && numDataArgs > 0) {
3040    CheckFormatHandler::EmitFormatDiagnostic(
3041      *this, inFunctionCall, Args[format_idx],
3042      PDiag(diag::warn_empty_format_string), FExpr->getLocStart(),
3043      /*IsStringLocation*/true, OrigFormatExpr->getSourceRange());
3044    return;
3045  }
3046
3047  if (Type == FST_Printf || Type == FST_NSString) {
3048    CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg,
3049                         numDataArgs, (Type == FST_NSString),
3050                         Str, HasVAListArg, Args, NumArgs, format_idx,
3051                         inFunctionCall, CallType);
3052
3053    if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen,
3054                                                  getLangOpts(),
3055                                                  Context.getTargetInfo()))
3056      H.DoneProcessing();
3057  } else if (Type == FST_Scanf) {
3058    CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, numDataArgs,
3059                        Str, HasVAListArg, Args, NumArgs, format_idx,
3060                        inFunctionCall, CallType);
3061
3062    if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen,
3063                                                 getLangOpts(),
3064                                                 Context.getTargetInfo()))
3065      H.DoneProcessing();
3066  } // TODO: handle other formats
3067}
3068
3069//===--- CHECK: Standard memory functions ---------------------------------===//
3070
3071/// \brief Determine whether the given type is a dynamic class type (e.g.,
3072/// whether it has a vtable).
3073static bool isDynamicClassType(QualType T) {
3074  if (CXXRecordDecl *Record = T->getAsCXXRecordDecl())
3075    if (CXXRecordDecl *Definition = Record->getDefinition())
3076      if (Definition->isDynamicClass())
3077        return true;
3078
3079  return false;
3080}
3081
3082/// \brief If E is a sizeof expression, returns its argument expression,
3083/// otherwise returns NULL.
3084static const Expr *getSizeOfExprArg(const Expr* E) {
3085  if (const UnaryExprOrTypeTraitExpr *SizeOf =
3086      dyn_cast<UnaryExprOrTypeTraitExpr>(E))
3087    if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType())
3088      return SizeOf->getArgumentExpr()->IgnoreParenImpCasts();
3089
3090  return 0;
3091}
3092
3093/// \brief If E is a sizeof expression, returns its argument type.
3094static QualType getSizeOfArgType(const Expr* E) {
3095  if (const UnaryExprOrTypeTraitExpr *SizeOf =
3096      dyn_cast<UnaryExprOrTypeTraitExpr>(E))
3097    if (SizeOf->getKind() == clang::UETT_SizeOf)
3098      return SizeOf->getTypeOfArgument();
3099
3100  return QualType();
3101}
3102
3103/// \brief Check for dangerous or invalid arguments to memset().
3104///
3105/// This issues warnings on known problematic, dangerous or unspecified
3106/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp'
3107/// function calls.
3108///
3109/// \param Call The call expression to diagnose.
3110void Sema::CheckMemaccessArguments(const CallExpr *Call,
3111                                   unsigned BId,
3112                                   IdentifierInfo *FnName) {
3113  assert(BId != 0);
3114
3115  // It is possible to have a non-standard definition of memset.  Validate
3116  // we have enough arguments, and if not, abort further checking.
3117  unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3);
3118  if (Call->getNumArgs() < ExpectedNumArgs)
3119    return;
3120
3121  unsigned LastArg = (BId == Builtin::BImemset ||
3122                      BId == Builtin::BIstrndup ? 1 : 2);
3123  unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2);
3124  const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts();
3125
3126  // We have special checking when the length is a sizeof expression.
3127  QualType SizeOfArgTy = getSizeOfArgType(LenExpr);
3128  const Expr *SizeOfArg = getSizeOfExprArg(LenExpr);
3129  llvm::FoldingSetNodeID SizeOfArgID;
3130
3131  for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) {
3132    const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts();
3133    SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange();
3134
3135    QualType DestTy = Dest->getType();
3136    if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) {
3137      QualType PointeeTy = DestPtrTy->getPointeeType();
3138
3139      // Never warn about void type pointers. This can be used to suppress
3140      // false positives.
3141      if (PointeeTy->isVoidType())
3142        continue;
3143
3144      // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by
3145      // actually comparing the expressions for equality. Because computing the
3146      // expression IDs can be expensive, we only do this if the diagnostic is
3147      // enabled.
3148      if (SizeOfArg &&
3149          Diags.getDiagnosticLevel(diag::warn_sizeof_pointer_expr_memaccess,
3150                                   SizeOfArg->getExprLoc())) {
3151        // We only compute IDs for expressions if the warning is enabled, and
3152        // cache the sizeof arg's ID.
3153        if (SizeOfArgID == llvm::FoldingSetNodeID())
3154          SizeOfArg->Profile(SizeOfArgID, Context, true);
3155        llvm::FoldingSetNodeID DestID;
3156        Dest->Profile(DestID, Context, true);
3157        if (DestID == SizeOfArgID) {
3158          // TODO: For strncpy() and friends, this could suggest sizeof(dst)
3159          //       over sizeof(src) as well.
3160          unsigned ActionIdx = 0; // Default is to suggest dereferencing.
3161          StringRef ReadableName = FnName->getName();
3162
3163          if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest))
3164            if (UnaryOp->getOpcode() == UO_AddrOf)
3165              ActionIdx = 1; // If its an address-of operator, just remove it.
3166          if (Context.getTypeSize(PointeeTy) == Context.getCharWidth())
3167            ActionIdx = 2; // If the pointee's size is sizeof(char),
3168                           // suggest an explicit length.
3169
3170          // If the function is defined as a builtin macro, do not show macro
3171          // expansion.
3172          SourceLocation SL = SizeOfArg->getExprLoc();
3173          SourceRange DSR = Dest->getSourceRange();
3174          SourceRange SSR = SizeOfArg->getSourceRange();
3175          SourceManager &SM  = PP.getSourceManager();
3176
3177          if (SM.isMacroArgExpansion(SL)) {
3178            ReadableName = Lexer::getImmediateMacroName(SL, SM, LangOpts);
3179            SL = SM.getSpellingLoc(SL);
3180            DSR = SourceRange(SM.getSpellingLoc(DSR.getBegin()),
3181                             SM.getSpellingLoc(DSR.getEnd()));
3182            SSR = SourceRange(SM.getSpellingLoc(SSR.getBegin()),
3183                             SM.getSpellingLoc(SSR.getEnd()));
3184          }
3185
3186          DiagRuntimeBehavior(SL, SizeOfArg,
3187                              PDiag(diag::warn_sizeof_pointer_expr_memaccess)
3188                                << ReadableName
3189                                << PointeeTy
3190                                << DestTy
3191                                << DSR
3192                                << SSR);
3193          DiagRuntimeBehavior(SL, SizeOfArg,
3194                         PDiag(diag::warn_sizeof_pointer_expr_memaccess_note)
3195                                << ActionIdx
3196                                << SSR);
3197
3198          break;
3199        }
3200      }
3201
3202      // Also check for cases where the sizeof argument is the exact same
3203      // type as the memory argument, and where it points to a user-defined
3204      // record type.
3205      if (SizeOfArgTy != QualType()) {
3206        if (PointeeTy->isRecordType() &&
3207            Context.typesAreCompatible(SizeOfArgTy, DestTy)) {
3208          DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest,
3209                              PDiag(diag::warn_sizeof_pointer_type_memaccess)
3210                                << FnName << SizeOfArgTy << ArgIdx
3211                                << PointeeTy << Dest->getSourceRange()
3212                                << LenExpr->getSourceRange());
3213          break;
3214        }
3215      }
3216
3217      // Always complain about dynamic classes.
3218      if (isDynamicClassType(PointeeTy)) {
3219
3220        unsigned OperationType = 0;
3221        // "overwritten" if we're warning about the destination for any call
3222        // but memcmp; otherwise a verb appropriate to the call.
3223        if (ArgIdx != 0 || BId == Builtin::BImemcmp) {
3224          if (BId == Builtin::BImemcpy)
3225            OperationType = 1;
3226          else if(BId == Builtin::BImemmove)
3227            OperationType = 2;
3228          else if (BId == Builtin::BImemcmp)
3229            OperationType = 3;
3230        }
3231
3232        DiagRuntimeBehavior(
3233          Dest->getExprLoc(), Dest,
3234          PDiag(diag::warn_dyn_class_memaccess)
3235            << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx)
3236            << FnName << PointeeTy
3237            << OperationType
3238            << Call->getCallee()->getSourceRange());
3239      } else if (PointeeTy.hasNonTrivialObjCLifetime() &&
3240               BId != Builtin::BImemset)
3241        DiagRuntimeBehavior(
3242          Dest->getExprLoc(), Dest,
3243          PDiag(diag::warn_arc_object_memaccess)
3244            << ArgIdx << FnName << PointeeTy
3245            << Call->getCallee()->getSourceRange());
3246      else
3247        continue;
3248
3249      DiagRuntimeBehavior(
3250        Dest->getExprLoc(), Dest,
3251        PDiag(diag::note_bad_memaccess_silence)
3252          << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)"));
3253      break;
3254    }
3255  }
3256}
3257
3258// A little helper routine: ignore addition and subtraction of integer literals.
3259// This intentionally does not ignore all integer constant expressions because
3260// we don't want to remove sizeof().
3261static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) {
3262  Ex = Ex->IgnoreParenCasts();
3263
3264  for (;;) {
3265    const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex);
3266    if (!BO || !BO->isAdditiveOp())
3267      break;
3268
3269    const Expr *RHS = BO->getRHS()->IgnoreParenCasts();
3270    const Expr *LHS = BO->getLHS()->IgnoreParenCasts();
3271
3272    if (isa<IntegerLiteral>(RHS))
3273      Ex = LHS;
3274    else if (isa<IntegerLiteral>(LHS))
3275      Ex = RHS;
3276    else
3277      break;
3278  }
3279
3280  return Ex;
3281}
3282
3283static bool isConstantSizeArrayWithMoreThanOneElement(QualType Ty,
3284                                                      ASTContext &Context) {
3285  // Only handle constant-sized or VLAs, but not flexible members.
3286  if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(Ty)) {
3287    // Only issue the FIXIT for arrays of size > 1.
3288    if (CAT->getSize().getSExtValue() <= 1)
3289      return false;
3290  } else if (!Ty->isVariableArrayType()) {
3291    return false;
3292  }
3293  return true;
3294}
3295
3296// Warn if the user has made the 'size' argument to strlcpy or strlcat
3297// be the size of the source, instead of the destination.
3298void Sema::CheckStrlcpycatArguments(const CallExpr *Call,
3299                                    IdentifierInfo *FnName) {
3300
3301  // Don't crash if the user has the wrong number of arguments
3302  if (Call->getNumArgs() != 3)
3303    return;
3304
3305  const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context);
3306  const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context);
3307  const Expr *CompareWithSrc = NULL;
3308
3309  // Look for 'strlcpy(dst, x, sizeof(x))'
3310  if (const Expr *Ex = getSizeOfExprArg(SizeArg))
3311    CompareWithSrc = Ex;
3312  else {
3313    // Look for 'strlcpy(dst, x, strlen(x))'
3314    if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) {
3315      if (SizeCall->isBuiltinCall() == Builtin::BIstrlen
3316          && SizeCall->getNumArgs() == 1)
3317        CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context);
3318    }
3319  }
3320
3321  if (!CompareWithSrc)
3322    return;
3323
3324  // Determine if the argument to sizeof/strlen is equal to the source
3325  // argument.  In principle there's all kinds of things you could do
3326  // here, for instance creating an == expression and evaluating it with
3327  // EvaluateAsBooleanCondition, but this uses a more direct technique:
3328  const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg);
3329  if (!SrcArgDRE)
3330    return;
3331
3332  const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc);
3333  if (!CompareWithSrcDRE ||
3334      SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl())
3335    return;
3336
3337  const Expr *OriginalSizeArg = Call->getArg(2);
3338  Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size)
3339    << OriginalSizeArg->getSourceRange() << FnName;
3340
3341  // Output a FIXIT hint if the destination is an array (rather than a
3342  // pointer to an array).  This could be enhanced to handle some
3343  // pointers if we know the actual size, like if DstArg is 'array+2'
3344  // we could say 'sizeof(array)-2'.
3345  const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts();
3346  if (!isConstantSizeArrayWithMoreThanOneElement(DstArg->getType(), Context))
3347    return;
3348
3349  SmallString<128> sizeString;
3350  llvm::raw_svector_ostream OS(sizeString);
3351  OS << "sizeof(";
3352  DstArg->printPretty(OS, 0, getPrintingPolicy());
3353  OS << ")";
3354
3355  Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size)
3356    << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(),
3357                                    OS.str());
3358}
3359
3360/// Check if two expressions refer to the same declaration.
3361static bool referToTheSameDecl(const Expr *E1, const Expr *E2) {
3362  if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1))
3363    if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2))
3364      return D1->getDecl() == D2->getDecl();
3365  return false;
3366}
3367
3368static const Expr *getStrlenExprArg(const Expr *E) {
3369  if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
3370    const FunctionDecl *FD = CE->getDirectCallee();
3371    if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen)
3372      return 0;
3373    return CE->getArg(0)->IgnoreParenCasts();
3374  }
3375  return 0;
3376}
3377
3378// Warn on anti-patterns as the 'size' argument to strncat.
3379// The correct size argument should look like following:
3380//   strncat(dst, src, sizeof(dst) - strlen(dest) - 1);
3381void Sema::CheckStrncatArguments(const CallExpr *CE,
3382                                 IdentifierInfo *FnName) {
3383  // Don't crash if the user has the wrong number of arguments.
3384  if (CE->getNumArgs() < 3)
3385    return;
3386  const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts();
3387  const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts();
3388  const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts();
3389
3390  // Identify common expressions, which are wrongly used as the size argument
3391  // to strncat and may lead to buffer overflows.
3392  unsigned PatternType = 0;
3393  if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) {
3394    // - sizeof(dst)
3395    if (referToTheSameDecl(SizeOfArg, DstArg))
3396      PatternType = 1;
3397    // - sizeof(src)
3398    else if (referToTheSameDecl(SizeOfArg, SrcArg))
3399      PatternType = 2;
3400  } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) {
3401    if (BE->getOpcode() == BO_Sub) {
3402      const Expr *L = BE->getLHS()->IgnoreParenCasts();
3403      const Expr *R = BE->getRHS()->IgnoreParenCasts();
3404      // - sizeof(dst) - strlen(dst)
3405      if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) &&
3406          referToTheSameDecl(DstArg, getStrlenExprArg(R)))
3407        PatternType = 1;
3408      // - sizeof(src) - (anything)
3409      else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L)))
3410        PatternType = 2;
3411    }
3412  }
3413
3414  if (PatternType == 0)
3415    return;
3416
3417  // Generate the diagnostic.
3418  SourceLocation SL = LenArg->getLocStart();
3419  SourceRange SR = LenArg->getSourceRange();
3420  SourceManager &SM  = PP.getSourceManager();
3421
3422  // If the function is defined as a builtin macro, do not show macro expansion.
3423  if (SM.isMacroArgExpansion(SL)) {
3424    SL = SM.getSpellingLoc(SL);
3425    SR = SourceRange(SM.getSpellingLoc(SR.getBegin()),
3426                     SM.getSpellingLoc(SR.getEnd()));
3427  }
3428
3429  // Check if the destination is an array (rather than a pointer to an array).
3430  QualType DstTy = DstArg->getType();
3431  bool isKnownSizeArray = isConstantSizeArrayWithMoreThanOneElement(DstTy,
3432                                                                    Context);
3433  if (!isKnownSizeArray) {
3434    if (PatternType == 1)
3435      Diag(SL, diag::warn_strncat_wrong_size) << SR;
3436    else
3437      Diag(SL, diag::warn_strncat_src_size) << SR;
3438    return;
3439  }
3440
3441  if (PatternType == 1)
3442    Diag(SL, diag::warn_strncat_large_size) << SR;
3443  else
3444    Diag(SL, diag::warn_strncat_src_size) << SR;
3445
3446  SmallString<128> sizeString;
3447  llvm::raw_svector_ostream OS(sizeString);
3448  OS << "sizeof(";
3449  DstArg->printPretty(OS, 0, getPrintingPolicy());
3450  OS << ") - ";
3451  OS << "strlen(";
3452  DstArg->printPretty(OS, 0, getPrintingPolicy());
3453  OS << ") - 1";
3454
3455  Diag(SL, diag::note_strncat_wrong_size)
3456    << FixItHint::CreateReplacement(SR, OS.str());
3457}
3458
3459//===--- CHECK: Return Address of Stack Variable --------------------------===//
3460
3461static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
3462                     Decl *ParentDecl);
3463static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars,
3464                      Decl *ParentDecl);
3465
3466/// CheckReturnStackAddr - Check if a return statement returns the address
3467///   of a stack variable.
3468void
3469Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType,
3470                           SourceLocation ReturnLoc) {
3471
3472  Expr *stackE = 0;
3473  SmallVector<DeclRefExpr *, 8> refVars;
3474
3475  // Perform checking for returned stack addresses, local blocks,
3476  // label addresses or references to temporaries.
3477  if (lhsType->isPointerType() ||
3478      (!getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) {
3479    stackE = EvalAddr(RetValExp, refVars, /*ParentDecl=*/0);
3480  } else if (lhsType->isReferenceType()) {
3481    stackE = EvalVal(RetValExp, refVars, /*ParentDecl=*/0);
3482  }
3483
3484  if (stackE == 0)
3485    return; // Nothing suspicious was found.
3486
3487  SourceLocation diagLoc;
3488  SourceRange diagRange;
3489  if (refVars.empty()) {
3490    diagLoc = stackE->getLocStart();
3491    diagRange = stackE->getSourceRange();
3492  } else {
3493    // We followed through a reference variable. 'stackE' contains the
3494    // problematic expression but we will warn at the return statement pointing
3495    // at the reference variable. We will later display the "trail" of
3496    // reference variables using notes.
3497    diagLoc = refVars[0]->getLocStart();
3498    diagRange = refVars[0]->getSourceRange();
3499  }
3500
3501  if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var.
3502    Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref
3503                                             : diag::warn_ret_stack_addr)
3504     << DR->getDecl()->getDeclName() << diagRange;
3505  } else if (isa<BlockExpr>(stackE)) { // local block.
3506    Diag(diagLoc, diag::err_ret_local_block) << diagRange;
3507  } else if (isa<AddrLabelExpr>(stackE)) { // address of label.
3508    Diag(diagLoc, diag::warn_ret_addr_label) << diagRange;
3509  } else { // local temporary.
3510    Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref
3511                                             : diag::warn_ret_local_temp_addr)
3512     << diagRange;
3513  }
3514
3515  // Display the "trail" of reference variables that we followed until we
3516  // found the problematic expression using notes.
3517  for (unsigned i = 0, e = refVars.size(); i != e; ++i) {
3518    VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl());
3519    // If this var binds to another reference var, show the range of the next
3520    // var, otherwise the var binds to the problematic expression, in which case
3521    // show the range of the expression.
3522    SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange()
3523                                  : stackE->getSourceRange();
3524    Diag(VD->getLocation(), diag::note_ref_var_local_bind)
3525      << VD->getDeclName() << range;
3526  }
3527}
3528
3529/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that
3530///  check if the expression in a return statement evaluates to an address
3531///  to a location on the stack, a local block, an address of a label, or a
3532///  reference to local temporary. The recursion is used to traverse the
3533///  AST of the return expression, with recursion backtracking when we
3534///  encounter a subexpression that (1) clearly does not lead to one of the
3535///  above problematic expressions (2) is something we cannot determine leads to
3536///  a problematic expression based on such local checking.
3537///
3538///  Both EvalAddr and EvalVal follow through reference variables to evaluate
3539///  the expression that they point to. Such variables are added to the
3540///  'refVars' vector so that we know what the reference variable "trail" was.
3541///
3542///  EvalAddr processes expressions that are pointers that are used as
3543///  references (and not L-values).  EvalVal handles all other values.
3544///  At the base case of the recursion is a check for the above problematic
3545///  expressions.
3546///
3547///  This implementation handles:
3548///
3549///   * pointer-to-pointer casts
3550///   * implicit conversions from array references to pointers
3551///   * taking the address of fields
3552///   * arbitrary interplay between "&" and "*" operators
3553///   * pointer arithmetic from an address of a stack variable
3554///   * taking the address of an array element where the array is on the stack
3555static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
3556                      Decl *ParentDecl) {
3557  if (E->isTypeDependent())
3558      return NULL;
3559
3560  // We should only be called for evaluating pointer expressions.
3561  assert((E->getType()->isAnyPointerType() ||
3562          E->getType()->isBlockPointerType() ||
3563          E->getType()->isObjCQualifiedIdType()) &&
3564         "EvalAddr only works on pointers");
3565
3566  E = E->IgnoreParens();
3567
3568  // Our "symbolic interpreter" is just a dispatch off the currently
3569  // viewed AST node.  We then recursively traverse the AST by calling
3570  // EvalAddr and EvalVal appropriately.
3571  switch (E->getStmtClass()) {
3572  case Stmt::DeclRefExprClass: {
3573    DeclRefExpr *DR = cast<DeclRefExpr>(E);
3574
3575    if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl()))
3576      // If this is a reference variable, follow through to the expression that
3577      // it points to.
3578      if (V->hasLocalStorage() &&
3579          V->getType()->isReferenceType() && V->hasInit()) {
3580        // Add the reference variable to the "trail".
3581        refVars.push_back(DR);
3582        return EvalAddr(V->getInit(), refVars, ParentDecl);
3583      }
3584
3585    return NULL;
3586  }
3587
3588  case Stmt::UnaryOperatorClass: {
3589    // The only unary operator that make sense to handle here
3590    // is AddrOf.  All others don't make sense as pointers.
3591    UnaryOperator *U = cast<UnaryOperator>(E);
3592
3593    if (U->getOpcode() == UO_AddrOf)
3594      return EvalVal(U->getSubExpr(), refVars, ParentDecl);
3595    else
3596      return NULL;
3597  }
3598
3599  case Stmt::BinaryOperatorClass: {
3600    // Handle pointer arithmetic.  All other binary operators are not valid
3601    // in this context.
3602    BinaryOperator *B = cast<BinaryOperator>(E);
3603    BinaryOperatorKind op = B->getOpcode();
3604
3605    if (op != BO_Add && op != BO_Sub)
3606      return NULL;
3607
3608    Expr *Base = B->getLHS();
3609
3610    // Determine which argument is the real pointer base.  It could be
3611    // the RHS argument instead of the LHS.
3612    if (!Base->getType()->isPointerType()) Base = B->getRHS();
3613
3614    assert (Base->getType()->isPointerType());
3615    return EvalAddr(Base, refVars, ParentDecl);
3616  }
3617
3618  // For conditional operators we need to see if either the LHS or RHS are
3619  // valid DeclRefExpr*s.  If one of them is valid, we return it.
3620  case Stmt::ConditionalOperatorClass: {
3621    ConditionalOperator *C = cast<ConditionalOperator>(E);
3622
3623    // Handle the GNU extension for missing LHS.
3624    if (Expr *lhsExpr = C->getLHS()) {
3625    // In C++, we can have a throw-expression, which has 'void' type.
3626      if (!lhsExpr->getType()->isVoidType())
3627        if (Expr* LHS = EvalAddr(lhsExpr, refVars, ParentDecl))
3628          return LHS;
3629    }
3630
3631    // In C++, we can have a throw-expression, which has 'void' type.
3632    if (C->getRHS()->getType()->isVoidType())
3633      return NULL;
3634
3635    return EvalAddr(C->getRHS(), refVars, ParentDecl);
3636  }
3637
3638  case Stmt::BlockExprClass:
3639    if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures())
3640      return E; // local block.
3641    return NULL;
3642
3643  case Stmt::AddrLabelExprClass:
3644    return E; // address of label.
3645
3646  case Stmt::ExprWithCleanupsClass:
3647    return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,
3648                    ParentDecl);
3649
3650  // For casts, we need to handle conversions from arrays to
3651  // pointer values, and pointer-to-pointer conversions.
3652  case Stmt::ImplicitCastExprClass:
3653  case Stmt::CStyleCastExprClass:
3654  case Stmt::CXXFunctionalCastExprClass:
3655  case Stmt::ObjCBridgedCastExprClass:
3656  case Stmt::CXXStaticCastExprClass:
3657  case Stmt::CXXDynamicCastExprClass:
3658  case Stmt::CXXConstCastExprClass:
3659  case Stmt::CXXReinterpretCastExprClass: {
3660    Expr* SubExpr = cast<CastExpr>(E)->getSubExpr();
3661    switch (cast<CastExpr>(E)->getCastKind()) {
3662    case CK_BitCast:
3663    case CK_LValueToRValue:
3664    case CK_NoOp:
3665    case CK_BaseToDerived:
3666    case CK_DerivedToBase:
3667    case CK_UncheckedDerivedToBase:
3668    case CK_Dynamic:
3669    case CK_CPointerToObjCPointerCast:
3670    case CK_BlockPointerToObjCPointerCast:
3671    case CK_AnyPointerToBlockPointerCast:
3672      return EvalAddr(SubExpr, refVars, ParentDecl);
3673
3674    case CK_ArrayToPointerDecay:
3675      return EvalVal(SubExpr, refVars, ParentDecl);
3676
3677    default:
3678      return 0;
3679    }
3680  }
3681
3682  case Stmt::MaterializeTemporaryExprClass:
3683    if (Expr *Result = EvalAddr(
3684                         cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
3685                                refVars, ParentDecl))
3686      return Result;
3687
3688    return E;
3689
3690  // Everything else: we simply don't reason about them.
3691  default:
3692    return NULL;
3693  }
3694}
3695
3696
3697///  EvalVal - This function is complements EvalAddr in the mutual recursion.
3698///   See the comments for EvalAddr for more details.
3699static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
3700                     Decl *ParentDecl) {
3701do {
3702  // We should only be called for evaluating non-pointer expressions, or
3703  // expressions with a pointer type that are not used as references but instead
3704  // are l-values (e.g., DeclRefExpr with a pointer type).
3705
3706  // Our "symbolic interpreter" is just a dispatch off the currently
3707  // viewed AST node.  We then recursively traverse the AST by calling
3708  // EvalAddr and EvalVal appropriately.
3709
3710  E = E->IgnoreParens();
3711  switch (E->getStmtClass()) {
3712  case Stmt::ImplicitCastExprClass: {
3713    ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E);
3714    if (IE->getValueKind() == VK_LValue) {
3715      E = IE->getSubExpr();
3716      continue;
3717    }
3718    return NULL;
3719  }
3720
3721  case Stmt::ExprWithCleanupsClass:
3722    return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,ParentDecl);
3723
3724  case Stmt::DeclRefExprClass: {
3725    // When we hit a DeclRefExpr we are looking at code that refers to a
3726    // variable's name. If it's not a reference variable we check if it has
3727    // local storage within the function, and if so, return the expression.
3728    DeclRefExpr *DR = cast<DeclRefExpr>(E);
3729
3730    if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) {
3731      // Check if it refers to itself, e.g. "int& i = i;".
3732      if (V == ParentDecl)
3733        return DR;
3734
3735      if (V->hasLocalStorage()) {
3736        if (!V->getType()->isReferenceType())
3737          return DR;
3738
3739        // Reference variable, follow through to the expression that
3740        // it points to.
3741        if (V->hasInit()) {
3742          // Add the reference variable to the "trail".
3743          refVars.push_back(DR);
3744          return EvalVal(V->getInit(), refVars, V);
3745        }
3746      }
3747    }
3748
3749    return NULL;
3750  }
3751
3752  case Stmt::UnaryOperatorClass: {
3753    // The only unary operator that make sense to handle here
3754    // is Deref.  All others don't resolve to a "name."  This includes
3755    // handling all sorts of rvalues passed to a unary operator.
3756    UnaryOperator *U = cast<UnaryOperator>(E);
3757
3758    if (U->getOpcode() == UO_Deref)
3759      return EvalAddr(U->getSubExpr(), refVars, ParentDecl);
3760
3761    return NULL;
3762  }
3763
3764  case Stmt::ArraySubscriptExprClass: {
3765    // Array subscripts are potential references to data on the stack.  We
3766    // retrieve the DeclRefExpr* for the array variable if it indeed
3767    // has local storage.
3768    return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars,ParentDecl);
3769  }
3770
3771  case Stmt::ConditionalOperatorClass: {
3772    // For conditional operators we need to see if either the LHS or RHS are
3773    // non-NULL Expr's.  If one is non-NULL, we return it.
3774    ConditionalOperator *C = cast<ConditionalOperator>(E);
3775
3776    // Handle the GNU extension for missing LHS.
3777    if (Expr *lhsExpr = C->getLHS())
3778      if (Expr *LHS = EvalVal(lhsExpr, refVars, ParentDecl))
3779        return LHS;
3780
3781    return EvalVal(C->getRHS(), refVars, ParentDecl);
3782  }
3783
3784  // Accesses to members are potential references to data on the stack.
3785  case Stmt::MemberExprClass: {
3786    MemberExpr *M = cast<MemberExpr>(E);
3787
3788    // Check for indirect access.  We only want direct field accesses.
3789    if (M->isArrow())
3790      return NULL;
3791
3792    // Check whether the member type is itself a reference, in which case
3793    // we're not going to refer to the member, but to what the member refers to.
3794    if (M->getMemberDecl()->getType()->isReferenceType())
3795      return NULL;
3796
3797    return EvalVal(M->getBase(), refVars, ParentDecl);
3798  }
3799
3800  case Stmt::MaterializeTemporaryExprClass:
3801    if (Expr *Result = EvalVal(
3802                          cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
3803                               refVars, ParentDecl))
3804      return Result;
3805
3806    return E;
3807
3808  default:
3809    // Check that we don't return or take the address of a reference to a
3810    // temporary. This is only useful in C++.
3811    if (!E->isTypeDependent() && E->isRValue())
3812      return E;
3813
3814    // Everything else: we simply don't reason about them.
3815    return NULL;
3816  }
3817} while (true);
3818}
3819
3820//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===//
3821
3822/// Check for comparisons of floating point operands using != and ==.
3823/// Issue a warning if these are no self-comparisons, as they are not likely
3824/// to do what the programmer intended.
3825void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) {
3826  Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts();
3827  Expr* RightExprSansParen = RHS->IgnoreParenImpCasts();
3828
3829  // Special case: check for x == x (which is OK).
3830  // Do not emit warnings for such cases.
3831  if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen))
3832    if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen))
3833      if (DRL->getDecl() == DRR->getDecl())
3834        return;
3835
3836
3837  // Special case: check for comparisons against literals that can be exactly
3838  //  represented by APFloat.  In such cases, do not emit a warning.  This
3839  //  is a heuristic: often comparison against such literals are used to
3840  //  detect if a value in a variable has not changed.  This clearly can
3841  //  lead to false negatives.
3842  if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) {
3843    if (FLL->isExact())
3844      return;
3845  } else
3846    if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen))
3847      if (FLR->isExact())
3848        return;
3849
3850  // Check for comparisons with builtin types.
3851  if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen))
3852    if (CL->isBuiltinCall())
3853      return;
3854
3855  if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen))
3856    if (CR->isBuiltinCall())
3857      return;
3858
3859  // Emit the diagnostic.
3860  Diag(Loc, diag::warn_floatingpoint_eq)
3861    << LHS->getSourceRange() << RHS->getSourceRange();
3862}
3863
3864//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===//
3865//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===//
3866
3867namespace {
3868
3869/// Structure recording the 'active' range of an integer-valued
3870/// expression.
3871struct IntRange {
3872  /// The number of bits active in the int.
3873  unsigned Width;
3874
3875  /// True if the int is known not to have negative values.
3876  bool NonNegative;
3877
3878  IntRange(unsigned Width, bool NonNegative)
3879    : Width(Width), NonNegative(NonNegative)
3880  {}
3881
3882  /// Returns the range of the bool type.
3883  static IntRange forBoolType() {
3884    return IntRange(1, true);
3885  }
3886
3887  /// Returns the range of an opaque value of the given integral type.
3888  static IntRange forValueOfType(ASTContext &C, QualType T) {
3889    return forValueOfCanonicalType(C,
3890                          T->getCanonicalTypeInternal().getTypePtr());
3891  }
3892
3893  /// Returns the range of an opaque value of a canonical integral type.
3894  static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) {
3895    assert(T->isCanonicalUnqualified());
3896
3897    if (const VectorType *VT = dyn_cast<VectorType>(T))
3898      T = VT->getElementType().getTypePtr();
3899    if (const ComplexType *CT = dyn_cast<ComplexType>(T))
3900      T = CT->getElementType().getTypePtr();
3901
3902    // For enum types, use the known bit width of the enumerators.
3903    if (const EnumType *ET = dyn_cast<EnumType>(T)) {
3904      EnumDecl *Enum = ET->getDecl();
3905      if (!Enum->isCompleteDefinition())
3906        return IntRange(C.getIntWidth(QualType(T, 0)), false);
3907
3908      unsigned NumPositive = Enum->getNumPositiveBits();
3909      unsigned NumNegative = Enum->getNumNegativeBits();
3910
3911      return IntRange(std::max(NumPositive, NumNegative), NumNegative == 0);
3912    }
3913
3914    const BuiltinType *BT = cast<BuiltinType>(T);
3915    assert(BT->isInteger());
3916
3917    return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
3918  }
3919
3920  /// Returns the "target" range of a canonical integral type, i.e.
3921  /// the range of values expressible in the type.
3922  ///
3923  /// This matches forValueOfCanonicalType except that enums have the
3924  /// full range of their type, not the range of their enumerators.
3925  static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) {
3926    assert(T->isCanonicalUnqualified());
3927
3928    if (const VectorType *VT = dyn_cast<VectorType>(T))
3929      T = VT->getElementType().getTypePtr();
3930    if (const ComplexType *CT = dyn_cast<ComplexType>(T))
3931      T = CT->getElementType().getTypePtr();
3932    if (const EnumType *ET = dyn_cast<EnumType>(T))
3933      T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr();
3934
3935    const BuiltinType *BT = cast<BuiltinType>(T);
3936    assert(BT->isInteger());
3937
3938    return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
3939  }
3940
3941  /// Returns the supremum of two ranges: i.e. their conservative merge.
3942  static IntRange join(IntRange L, IntRange R) {
3943    return IntRange(std::max(L.Width, R.Width),
3944                    L.NonNegative && R.NonNegative);
3945  }
3946
3947  /// Returns the infinum of two ranges: i.e. their aggressive merge.
3948  static IntRange meet(IntRange L, IntRange R) {
3949    return IntRange(std::min(L.Width, R.Width),
3950                    L.NonNegative || R.NonNegative);
3951  }
3952};
3953
3954static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value,
3955                              unsigned MaxWidth) {
3956  if (value.isSigned() && value.isNegative())
3957    return IntRange(value.getMinSignedBits(), false);
3958
3959  if (value.getBitWidth() > MaxWidth)
3960    value = value.trunc(MaxWidth);
3961
3962  // isNonNegative() just checks the sign bit without considering
3963  // signedness.
3964  return IntRange(value.getActiveBits(), true);
3965}
3966
3967static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty,
3968                              unsigned MaxWidth) {
3969  if (result.isInt())
3970    return GetValueRange(C, result.getInt(), MaxWidth);
3971
3972  if (result.isVector()) {
3973    IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth);
3974    for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) {
3975      IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth);
3976      R = IntRange::join(R, El);
3977    }
3978    return R;
3979  }
3980
3981  if (result.isComplexInt()) {
3982    IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth);
3983    IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth);
3984    return IntRange::join(R, I);
3985  }
3986
3987  // This can happen with lossless casts to intptr_t of "based" lvalues.
3988  // Assume it might use arbitrary bits.
3989  // FIXME: The only reason we need to pass the type in here is to get
3990  // the sign right on this one case.  It would be nice if APValue
3991  // preserved this.
3992  assert(result.isLValue() || result.isAddrLabelDiff());
3993  return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType());
3994}
3995
3996/// Pseudo-evaluate the given integer expression, estimating the
3997/// range of values it might take.
3998///
3999/// \param MaxWidth - the width to which the value will be truncated
4000static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) {
4001  E = E->IgnoreParens();
4002
4003  // Try a full evaluation first.
4004  Expr::EvalResult result;
4005  if (E->EvaluateAsRValue(result, C))
4006    return GetValueRange(C, result.Val, E->getType(), MaxWidth);
4007
4008  // I think we only want to look through implicit casts here; if the
4009  // user has an explicit widening cast, we should treat the value as
4010  // being of the new, wider type.
4011  if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) {
4012    if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue)
4013      return GetExprRange(C, CE->getSubExpr(), MaxWidth);
4014
4015    IntRange OutputTypeRange = IntRange::forValueOfType(C, CE->getType());
4016
4017    bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast);
4018
4019    // Assume that non-integer casts can span the full range of the type.
4020    if (!isIntegerCast)
4021      return OutputTypeRange;
4022
4023    IntRange SubRange
4024      = GetExprRange(C, CE->getSubExpr(),
4025                     std::min(MaxWidth, OutputTypeRange.Width));
4026
4027    // Bail out if the subexpr's range is as wide as the cast type.
4028    if (SubRange.Width >= OutputTypeRange.Width)
4029      return OutputTypeRange;
4030
4031    // Otherwise, we take the smaller width, and we're non-negative if
4032    // either the output type or the subexpr is.
4033    return IntRange(SubRange.Width,
4034                    SubRange.NonNegative || OutputTypeRange.NonNegative);
4035  }
4036
4037  if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
4038    // If we can fold the condition, just take that operand.
4039    bool CondResult;
4040    if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C))
4041      return GetExprRange(C, CondResult ? CO->getTrueExpr()
4042                                        : CO->getFalseExpr(),
4043                          MaxWidth);
4044
4045    // Otherwise, conservatively merge.
4046    IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth);
4047    IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth);
4048    return IntRange::join(L, R);
4049  }
4050
4051  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
4052    switch (BO->getOpcode()) {
4053
4054    // Boolean-valued operations are single-bit and positive.
4055    case BO_LAnd:
4056    case BO_LOr:
4057    case BO_LT:
4058    case BO_GT:
4059    case BO_LE:
4060    case BO_GE:
4061    case BO_EQ:
4062    case BO_NE:
4063      return IntRange::forBoolType();
4064
4065    // The type of the assignments is the type of the LHS, so the RHS
4066    // is not necessarily the same type.
4067    case BO_MulAssign:
4068    case BO_DivAssign:
4069    case BO_RemAssign:
4070    case BO_AddAssign:
4071    case BO_SubAssign:
4072    case BO_XorAssign:
4073    case BO_OrAssign:
4074      // TODO: bitfields?
4075      return IntRange::forValueOfType(C, E->getType());
4076
4077    // Simple assignments just pass through the RHS, which will have
4078    // been coerced to the LHS type.
4079    case BO_Assign:
4080      // TODO: bitfields?
4081      return GetExprRange(C, BO->getRHS(), MaxWidth);
4082
4083    // Operations with opaque sources are black-listed.
4084    case BO_PtrMemD:
4085    case BO_PtrMemI:
4086      return IntRange::forValueOfType(C, E->getType());
4087
4088    // Bitwise-and uses the *infinum* of the two source ranges.
4089    case BO_And:
4090    case BO_AndAssign:
4091      return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth),
4092                            GetExprRange(C, BO->getRHS(), MaxWidth));
4093
4094    // Left shift gets black-listed based on a judgement call.
4095    case BO_Shl:
4096      // ...except that we want to treat '1 << (blah)' as logically
4097      // positive.  It's an important idiom.
4098      if (IntegerLiteral *I
4099            = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) {
4100        if (I->getValue() == 1) {
4101          IntRange R = IntRange::forValueOfType(C, E->getType());
4102          return IntRange(R.Width, /*NonNegative*/ true);
4103        }
4104      }
4105      // fallthrough
4106
4107    case BO_ShlAssign:
4108      return IntRange::forValueOfType(C, E->getType());
4109
4110    // Right shift by a constant can narrow its left argument.
4111    case BO_Shr:
4112    case BO_ShrAssign: {
4113      IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
4114
4115      // If the shift amount is a positive constant, drop the width by
4116      // that much.
4117      llvm::APSInt shift;
4118      if (BO->getRHS()->isIntegerConstantExpr(shift, C) &&
4119          shift.isNonNegative()) {
4120        unsigned zext = shift.getZExtValue();
4121        if (zext >= L.Width)
4122          L.Width = (L.NonNegative ? 0 : 1);
4123        else
4124          L.Width -= zext;
4125      }
4126
4127      return L;
4128    }
4129
4130    // Comma acts as its right operand.
4131    case BO_Comma:
4132      return GetExprRange(C, BO->getRHS(), MaxWidth);
4133
4134    // Black-list pointer subtractions.
4135    case BO_Sub:
4136      if (BO->getLHS()->getType()->isPointerType())
4137        return IntRange::forValueOfType(C, E->getType());
4138      break;
4139
4140    // The width of a division result is mostly determined by the size
4141    // of the LHS.
4142    case BO_Div: {
4143      // Don't 'pre-truncate' the operands.
4144      unsigned opWidth = C.getIntWidth(E->getType());
4145      IntRange L = GetExprRange(C, BO->getLHS(), opWidth);
4146
4147      // If the divisor is constant, use that.
4148      llvm::APSInt divisor;
4149      if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) {
4150        unsigned log2 = divisor.logBase2(); // floor(log_2(divisor))
4151        if (log2 >= L.Width)
4152          L.Width = (L.NonNegative ? 0 : 1);
4153        else
4154          L.Width = std::min(L.Width - log2, MaxWidth);
4155        return L;
4156      }
4157
4158      // Otherwise, just use the LHS's width.
4159      IntRange R = GetExprRange(C, BO->getRHS(), opWidth);
4160      return IntRange(L.Width, L.NonNegative && R.NonNegative);
4161    }
4162
4163    // The result of a remainder can't be larger than the result of
4164    // either side.
4165    case BO_Rem: {
4166      // Don't 'pre-truncate' the operands.
4167      unsigned opWidth = C.getIntWidth(E->getType());
4168      IntRange L = GetExprRange(C, BO->getLHS(), opWidth);
4169      IntRange R = GetExprRange(C, BO->getRHS(), opWidth);
4170
4171      IntRange meet = IntRange::meet(L, R);
4172      meet.Width = std::min(meet.Width, MaxWidth);
4173      return meet;
4174    }
4175
4176    // The default behavior is okay for these.
4177    case BO_Mul:
4178    case BO_Add:
4179    case BO_Xor:
4180    case BO_Or:
4181      break;
4182    }
4183
4184    // The default case is to treat the operation as if it were closed
4185    // on the narrowest type that encompasses both operands.
4186    IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
4187    IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth);
4188    return IntRange::join(L, R);
4189  }
4190
4191  if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
4192    switch (UO->getOpcode()) {
4193    // Boolean-valued operations are white-listed.
4194    case UO_LNot:
4195      return IntRange::forBoolType();
4196
4197    // Operations with opaque sources are black-listed.
4198    case UO_Deref:
4199    case UO_AddrOf: // should be impossible
4200      return IntRange::forValueOfType(C, E->getType());
4201
4202    default:
4203      return GetExprRange(C, UO->getSubExpr(), MaxWidth);
4204    }
4205  }
4206
4207  if (dyn_cast<OffsetOfExpr>(E)) {
4208    IntRange::forValueOfType(C, E->getType());
4209  }
4210
4211  if (FieldDecl *BitField = E->getBitField())
4212    return IntRange(BitField->getBitWidthValue(C),
4213                    BitField->getType()->isUnsignedIntegerOrEnumerationType());
4214
4215  return IntRange::forValueOfType(C, E->getType());
4216}
4217
4218static IntRange GetExprRange(ASTContext &C, Expr *E) {
4219  return GetExprRange(C, E, C.getIntWidth(E->getType()));
4220}
4221
4222/// Checks whether the given value, which currently has the given
4223/// source semantics, has the same value when coerced through the
4224/// target semantics.
4225static bool IsSameFloatAfterCast(const llvm::APFloat &value,
4226                                 const llvm::fltSemantics &Src,
4227                                 const llvm::fltSemantics &Tgt) {
4228  llvm::APFloat truncated = value;
4229
4230  bool ignored;
4231  truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored);
4232  truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored);
4233
4234  return truncated.bitwiseIsEqual(value);
4235}
4236
4237/// Checks whether the given value, which currently has the given
4238/// source semantics, has the same value when coerced through the
4239/// target semantics.
4240///
4241/// The value might be a vector of floats (or a complex number).
4242static bool IsSameFloatAfterCast(const APValue &value,
4243                                 const llvm::fltSemantics &Src,
4244                                 const llvm::fltSemantics &Tgt) {
4245  if (value.isFloat())
4246    return IsSameFloatAfterCast(value.getFloat(), Src, Tgt);
4247
4248  if (value.isVector()) {
4249    for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i)
4250      if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt))
4251        return false;
4252    return true;
4253  }
4254
4255  assert(value.isComplexFloat());
4256  return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) &&
4257          IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt));
4258}
4259
4260static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC);
4261
4262static bool IsZero(Sema &S, Expr *E) {
4263  // Suppress cases where we are comparing against an enum constant.
4264  if (const DeclRefExpr *DR =
4265      dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
4266    if (isa<EnumConstantDecl>(DR->getDecl()))
4267      return false;
4268
4269  // Suppress cases where the '0' value is expanded from a macro.
4270  if (E->getLocStart().isMacroID())
4271    return false;
4272
4273  llvm::APSInt Value;
4274  return E->isIntegerConstantExpr(Value, S.Context) && Value == 0;
4275}
4276
4277static bool HasEnumType(Expr *E) {
4278  // Strip off implicit integral promotions.
4279  while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
4280    if (ICE->getCastKind() != CK_IntegralCast &&
4281        ICE->getCastKind() != CK_NoOp)
4282      break;
4283    E = ICE->getSubExpr();
4284  }
4285
4286  return E->getType()->isEnumeralType();
4287}
4288
4289static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) {
4290  BinaryOperatorKind op = E->getOpcode();
4291  if (E->isValueDependent())
4292    return;
4293
4294  if (op == BO_LT && IsZero(S, E->getRHS())) {
4295    S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
4296      << "< 0" << "false" << HasEnumType(E->getLHS())
4297      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
4298  } else if (op == BO_GE && IsZero(S, E->getRHS())) {
4299    S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
4300      << ">= 0" << "true" << HasEnumType(E->getLHS())
4301      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
4302  } else if (op == BO_GT && IsZero(S, E->getLHS())) {
4303    S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
4304      << "0 >" << "false" << HasEnumType(E->getRHS())
4305      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
4306  } else if (op == BO_LE && IsZero(S, E->getLHS())) {
4307    S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
4308      << "0 <=" << "true" << HasEnumType(E->getRHS())
4309      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
4310  }
4311}
4312
4313static void DiagnoseOutOfRangeComparison(Sema &S, BinaryOperator *E,
4314                                         Expr *Constant, Expr *Other,
4315                                         llvm::APSInt Value,
4316                                         bool RhsConstant) {
4317  BinaryOperatorKind op = E->getOpcode();
4318  QualType OtherT = Other->getType();
4319  QualType ConstantT = Constant->getType();
4320  if (S.Context.hasSameUnqualifiedType(OtherT, ConstantT))
4321    return;
4322  assert((OtherT->isIntegerType() && ConstantT->isIntegerType())
4323         && "comparison with non-integer type");
4324  // FIXME. handle cases for signedness to catch (signed char)N == 200
4325  IntRange OtherRange = IntRange::forValueOfType(S.Context, OtherT);
4326  IntRange LitRange = GetValueRange(S.Context, Value, Value.getBitWidth());
4327  if (OtherRange.Width >= LitRange.Width)
4328    return;
4329  bool IsTrue = true;
4330  if (op == BO_EQ)
4331    IsTrue = false;
4332  else if (op == BO_NE)
4333    IsTrue = true;
4334  else if (RhsConstant) {
4335    if (op == BO_GT || op == BO_GE)
4336      IsTrue = !LitRange.NonNegative;
4337    else // op == BO_LT || op == BO_LE
4338      IsTrue = LitRange.NonNegative;
4339  } else {
4340    if (op == BO_LT || op == BO_LE)
4341      IsTrue = !LitRange.NonNegative;
4342    else // op == BO_GT || op == BO_GE
4343      IsTrue = LitRange.NonNegative;
4344  }
4345  SmallString<16> PrettySourceValue(Value.toString(10));
4346  S.Diag(E->getOperatorLoc(), diag::warn_out_of_range_compare)
4347  << PrettySourceValue << OtherT << IsTrue
4348  << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
4349}
4350
4351/// Analyze the operands of the given comparison.  Implements the
4352/// fallback case from AnalyzeComparison.
4353static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) {
4354  AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
4355  AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
4356}
4357
4358/// \brief Implements -Wsign-compare.
4359///
4360/// \param E the binary operator to check for warnings
4361static void AnalyzeComparison(Sema &S, BinaryOperator *E) {
4362  // The type the comparison is being performed in.
4363  QualType T = E->getLHS()->getType();
4364  assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType())
4365         && "comparison with mismatched types");
4366  if (E->isValueDependent())
4367    return AnalyzeImpConvsInComparison(S, E);
4368
4369  Expr *LHS = E->getLHS()->IgnoreParenImpCasts();
4370  Expr *RHS = E->getRHS()->IgnoreParenImpCasts();
4371
4372  bool IsComparisonConstant = false;
4373
4374  // Check whether an integer constant comparison results in a value
4375  // of 'true' or 'false'.
4376  if (T->isIntegralType(S.Context)) {
4377    llvm::APSInt RHSValue;
4378    bool IsRHSIntegralLiteral =
4379      RHS->isIntegerConstantExpr(RHSValue, S.Context);
4380    llvm::APSInt LHSValue;
4381    bool IsLHSIntegralLiteral =
4382      LHS->isIntegerConstantExpr(LHSValue, S.Context);
4383    if (IsRHSIntegralLiteral && !IsLHSIntegralLiteral)
4384        DiagnoseOutOfRangeComparison(S, E, RHS, LHS, RHSValue, true);
4385    else if (!IsRHSIntegralLiteral && IsLHSIntegralLiteral)
4386      DiagnoseOutOfRangeComparison(S, E, LHS, RHS, LHSValue, false);
4387    else
4388      IsComparisonConstant =
4389        (IsRHSIntegralLiteral && IsLHSIntegralLiteral);
4390  } else if (!T->hasUnsignedIntegerRepresentation())
4391      IsComparisonConstant = E->isIntegerConstantExpr(S.Context);
4392
4393  // We don't do anything special if this isn't an unsigned integral
4394  // comparison:  we're only interested in integral comparisons, and
4395  // signed comparisons only happen in cases we don't care to warn about.
4396  //
4397  // We also don't care about value-dependent expressions or expressions
4398  // whose result is a constant.
4399  if (!T->hasUnsignedIntegerRepresentation() || IsComparisonConstant)
4400    return AnalyzeImpConvsInComparison(S, E);
4401
4402  // Check to see if one of the (unmodified) operands is of different
4403  // signedness.
4404  Expr *signedOperand, *unsignedOperand;
4405  if (LHS->getType()->hasSignedIntegerRepresentation()) {
4406    assert(!RHS->getType()->hasSignedIntegerRepresentation() &&
4407           "unsigned comparison between two signed integer expressions?");
4408    signedOperand = LHS;
4409    unsignedOperand = RHS;
4410  } else if (RHS->getType()->hasSignedIntegerRepresentation()) {
4411    signedOperand = RHS;
4412    unsignedOperand = LHS;
4413  } else {
4414    CheckTrivialUnsignedComparison(S, E);
4415    return AnalyzeImpConvsInComparison(S, E);
4416  }
4417
4418  // Otherwise, calculate the effective range of the signed operand.
4419  IntRange signedRange = GetExprRange(S.Context, signedOperand);
4420
4421  // Go ahead and analyze implicit conversions in the operands.  Note
4422  // that we skip the implicit conversions on both sides.
4423  AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc());
4424  AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc());
4425
4426  // If the signed range is non-negative, -Wsign-compare won't fire,
4427  // but we should still check for comparisons which are always true
4428  // or false.
4429  if (signedRange.NonNegative)
4430    return CheckTrivialUnsignedComparison(S, E);
4431
4432  // For (in)equality comparisons, if the unsigned operand is a
4433  // constant which cannot collide with a overflowed signed operand,
4434  // then reinterpreting the signed operand as unsigned will not
4435  // change the result of the comparison.
4436  if (E->isEqualityOp()) {
4437    unsigned comparisonWidth = S.Context.getIntWidth(T);
4438    IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand);
4439
4440    // We should never be unable to prove that the unsigned operand is
4441    // non-negative.
4442    assert(unsignedRange.NonNegative && "unsigned range includes negative?");
4443
4444    if (unsignedRange.Width < comparisonWidth)
4445      return;
4446  }
4447
4448  S.DiagRuntimeBehavior(E->getOperatorLoc(), E,
4449    S.PDiag(diag::warn_mixed_sign_comparison)
4450      << LHS->getType() << RHS->getType()
4451      << LHS->getSourceRange() << RHS->getSourceRange());
4452}
4453
4454/// Analyzes an attempt to assign the given value to a bitfield.
4455///
4456/// Returns true if there was something fishy about the attempt.
4457static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init,
4458                                      SourceLocation InitLoc) {
4459  assert(Bitfield->isBitField());
4460  if (Bitfield->isInvalidDecl())
4461    return false;
4462
4463  // White-list bool bitfields.
4464  if (Bitfield->getType()->isBooleanType())
4465    return false;
4466
4467  // Ignore value- or type-dependent expressions.
4468  if (Bitfield->getBitWidth()->isValueDependent() ||
4469      Bitfield->getBitWidth()->isTypeDependent() ||
4470      Init->isValueDependent() ||
4471      Init->isTypeDependent())
4472    return false;
4473
4474  Expr *OriginalInit = Init->IgnoreParenImpCasts();
4475
4476  llvm::APSInt Value;
4477  if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects))
4478    return false;
4479
4480  unsigned OriginalWidth = Value.getBitWidth();
4481  unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context);
4482
4483  if (OriginalWidth <= FieldWidth)
4484    return false;
4485
4486  // Compute the value which the bitfield will contain.
4487  llvm::APSInt TruncatedValue = Value.trunc(FieldWidth);
4488  TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType());
4489
4490  // Check whether the stored value is equal to the original value.
4491  TruncatedValue = TruncatedValue.extend(OriginalWidth);
4492  if (llvm::APSInt::isSameValue(Value, TruncatedValue))
4493    return false;
4494
4495  // Special-case bitfields of width 1: booleans are naturally 0/1, and
4496  // therefore don't strictly fit into a signed bitfield of width 1.
4497  if (FieldWidth == 1 && Value == 1)
4498    return false;
4499
4500  std::string PrettyValue = Value.toString(10);
4501  std::string PrettyTrunc = TruncatedValue.toString(10);
4502
4503  S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant)
4504    << PrettyValue << PrettyTrunc << OriginalInit->getType()
4505    << Init->getSourceRange();
4506
4507  return true;
4508}
4509
4510/// Analyze the given simple or compound assignment for warning-worthy
4511/// operations.
4512static void AnalyzeAssignment(Sema &S, BinaryOperator *E) {
4513  // Just recurse on the LHS.
4514  AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
4515
4516  // We want to recurse on the RHS as normal unless we're assigning to
4517  // a bitfield.
4518  if (FieldDecl *Bitfield = E->getLHS()->getBitField()) {
4519    if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(),
4520                                  E->getOperatorLoc())) {
4521      // Recurse, ignoring any implicit conversions on the RHS.
4522      return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(),
4523                                        E->getOperatorLoc());
4524    }
4525  }
4526
4527  AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
4528}
4529
4530/// Diagnose an implicit cast;  purely a helper for CheckImplicitConversion.
4531static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T,
4532                            SourceLocation CContext, unsigned diag,
4533                            bool pruneControlFlow = false) {
4534  if (pruneControlFlow) {
4535    S.DiagRuntimeBehavior(E->getExprLoc(), E,
4536                          S.PDiag(diag)
4537                            << SourceType << T << E->getSourceRange()
4538                            << SourceRange(CContext));
4539    return;
4540  }
4541  S.Diag(E->getExprLoc(), diag)
4542    << SourceType << T << E->getSourceRange() << SourceRange(CContext);
4543}
4544
4545/// Diagnose an implicit cast;  purely a helper for CheckImplicitConversion.
4546static void DiagnoseImpCast(Sema &S, Expr *E, QualType T,
4547                            SourceLocation CContext, unsigned diag,
4548                            bool pruneControlFlow = false) {
4549  DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow);
4550}
4551
4552/// Diagnose an implicit cast from a literal expression. Does not warn when the
4553/// cast wouldn't lose information.
4554void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T,
4555                                    SourceLocation CContext) {
4556  // Try to convert the literal exactly to an integer. If we can, don't warn.
4557  bool isExact = false;
4558  const llvm::APFloat &Value = FL->getValue();
4559  llvm::APSInt IntegerValue(S.Context.getIntWidth(T),
4560                            T->hasUnsignedIntegerRepresentation());
4561  if (Value.convertToInteger(IntegerValue,
4562                             llvm::APFloat::rmTowardZero, &isExact)
4563      == llvm::APFloat::opOK && isExact)
4564    return;
4565
4566  SmallString<16> PrettySourceValue;
4567  Value.toString(PrettySourceValue);
4568  SmallString<16> PrettyTargetValue;
4569  if (T->isSpecificBuiltinType(BuiltinType::Bool))
4570    PrettyTargetValue = IntegerValue == 0 ? "false" : "true";
4571  else
4572    IntegerValue.toString(PrettyTargetValue);
4573
4574  S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer)
4575    << FL->getType() << T.getUnqualifiedType() << PrettySourceValue
4576    << PrettyTargetValue << FL->getSourceRange() << SourceRange(CContext);
4577}
4578
4579std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) {
4580  if (!Range.Width) return "0";
4581
4582  llvm::APSInt ValueInRange = Value;
4583  ValueInRange.setIsSigned(!Range.NonNegative);
4584  ValueInRange = ValueInRange.trunc(Range.Width);
4585  return ValueInRange.toString(10);
4586}
4587
4588static bool IsImplicitBoolFloatConversion(Sema &S, Expr *Ex, bool ToBool) {
4589  if (!isa<ImplicitCastExpr>(Ex))
4590    return false;
4591
4592  Expr *InnerE = Ex->IgnoreParenImpCasts();
4593  const Type *Target = S.Context.getCanonicalType(Ex->getType()).getTypePtr();
4594  const Type *Source =
4595    S.Context.getCanonicalType(InnerE->getType()).getTypePtr();
4596  if (Target->isDependentType())
4597    return false;
4598
4599  const BuiltinType *FloatCandidateBT =
4600    dyn_cast<BuiltinType>(ToBool ? Source : Target);
4601  const Type *BoolCandidateType = ToBool ? Target : Source;
4602
4603  return (BoolCandidateType->isSpecificBuiltinType(BuiltinType::Bool) &&
4604          FloatCandidateBT && (FloatCandidateBT->isFloatingPoint()));
4605}
4606
4607void CheckImplicitArgumentConversions(Sema &S, CallExpr *TheCall,
4608                                      SourceLocation CC) {
4609  unsigned NumArgs = TheCall->getNumArgs();
4610  for (unsigned i = 0; i < NumArgs; ++i) {
4611    Expr *CurrA = TheCall->getArg(i);
4612    if (!IsImplicitBoolFloatConversion(S, CurrA, true))
4613      continue;
4614
4615    bool IsSwapped = ((i > 0) &&
4616        IsImplicitBoolFloatConversion(S, TheCall->getArg(i - 1), false));
4617    IsSwapped |= ((i < (NumArgs - 1)) &&
4618        IsImplicitBoolFloatConversion(S, TheCall->getArg(i + 1), false));
4619    if (IsSwapped) {
4620      // Warn on this floating-point to bool conversion.
4621      DiagnoseImpCast(S, CurrA->IgnoreParenImpCasts(),
4622                      CurrA->getType(), CC,
4623                      diag::warn_impcast_floating_point_to_bool);
4624    }
4625  }
4626}
4627
4628void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
4629                             SourceLocation CC, bool *ICContext = 0) {
4630  if (E->isTypeDependent() || E->isValueDependent()) return;
4631
4632  const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr();
4633  const Type *Target = S.Context.getCanonicalType(T).getTypePtr();
4634  if (Source == Target) return;
4635  if (Target->isDependentType()) return;
4636
4637  // If the conversion context location is invalid don't complain. We also
4638  // don't want to emit a warning if the issue occurs from the expansion of
4639  // a system macro. The problem is that 'getSpellingLoc()' is slow, so we
4640  // delay this check as long as possible. Once we detect we are in that
4641  // scenario, we just return.
4642  if (CC.isInvalid())
4643    return;
4644
4645  // Diagnose implicit casts to bool.
4646  if (Target->isSpecificBuiltinType(BuiltinType::Bool)) {
4647    if (isa<StringLiteral>(E))
4648      // Warn on string literal to bool.  Checks for string literals in logical
4649      // expressions, for instances, assert(0 && "error here"), is prevented
4650      // by a check in AnalyzeImplicitConversions().
4651      return DiagnoseImpCast(S, E, T, CC,
4652                             diag::warn_impcast_string_literal_to_bool);
4653    if (Source->isFunctionType()) {
4654      // Warn on function to bool. Checks free functions and static member
4655      // functions. Weakly imported functions are excluded from the check,
4656      // since it's common to test their value to check whether the linker
4657      // found a definition for them.
4658      ValueDecl *D = 0;
4659      if (DeclRefExpr* R = dyn_cast<DeclRefExpr>(E)) {
4660        D = R->getDecl();
4661      } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) {
4662        D = M->getMemberDecl();
4663      }
4664
4665      if (D && !D->isWeak()) {
4666        if (FunctionDecl* F = dyn_cast<FunctionDecl>(D)) {
4667          S.Diag(E->getExprLoc(), diag::warn_impcast_function_to_bool)
4668            << F << E->getSourceRange() << SourceRange(CC);
4669          S.Diag(E->getExprLoc(), diag::note_function_to_bool_silence)
4670            << FixItHint::CreateInsertion(E->getExprLoc(), "&");
4671          QualType ReturnType;
4672          UnresolvedSet<4> NonTemplateOverloads;
4673          S.isExprCallable(*E, ReturnType, NonTemplateOverloads);
4674          if (!ReturnType.isNull()
4675              && ReturnType->isSpecificBuiltinType(BuiltinType::Bool))
4676            S.Diag(E->getExprLoc(), diag::note_function_to_bool_call)
4677              << FixItHint::CreateInsertion(
4678                 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()), "()");
4679          return;
4680        }
4681      }
4682    }
4683  }
4684
4685  // Strip vector types.
4686  if (isa<VectorType>(Source)) {
4687    if (!isa<VectorType>(Target)) {
4688      if (S.SourceMgr.isInSystemMacro(CC))
4689        return;
4690      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar);
4691    }
4692
4693    // If the vector cast is cast between two vectors of the same size, it is
4694    // a bitcast, not a conversion.
4695    if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target))
4696      return;
4697
4698    Source = cast<VectorType>(Source)->getElementType().getTypePtr();
4699    Target = cast<VectorType>(Target)->getElementType().getTypePtr();
4700  }
4701
4702  // Strip complex types.
4703  if (isa<ComplexType>(Source)) {
4704    if (!isa<ComplexType>(Target)) {
4705      if (S.SourceMgr.isInSystemMacro(CC))
4706        return;
4707
4708      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar);
4709    }
4710
4711    Source = cast<ComplexType>(Source)->getElementType().getTypePtr();
4712    Target = cast<ComplexType>(Target)->getElementType().getTypePtr();
4713  }
4714
4715  const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source);
4716  const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target);
4717
4718  // If the source is floating point...
4719  if (SourceBT && SourceBT->isFloatingPoint()) {
4720    // ...and the target is floating point...
4721    if (TargetBT && TargetBT->isFloatingPoint()) {
4722      // ...then warn if we're dropping FP rank.
4723
4724      // Builtin FP kinds are ordered by increasing FP rank.
4725      if (SourceBT->getKind() > TargetBT->getKind()) {
4726        // Don't warn about float constants that are precisely
4727        // representable in the target type.
4728        Expr::EvalResult result;
4729        if (E->EvaluateAsRValue(result, S.Context)) {
4730          // Value might be a float, a float vector, or a float complex.
4731          if (IsSameFloatAfterCast(result.Val,
4732                   S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)),
4733                   S.Context.getFloatTypeSemantics(QualType(SourceBT, 0))))
4734            return;
4735        }
4736
4737        if (S.SourceMgr.isInSystemMacro(CC))
4738          return;
4739
4740        DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision);
4741      }
4742      return;
4743    }
4744
4745    // If the target is integral, always warn.
4746    if (TargetBT && TargetBT->isInteger()) {
4747      if (S.SourceMgr.isInSystemMacro(CC))
4748        return;
4749
4750      Expr *InnerE = E->IgnoreParenImpCasts();
4751      // We also want to warn on, e.g., "int i = -1.234"
4752      if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE))
4753        if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus)
4754          InnerE = UOp->getSubExpr()->IgnoreParenImpCasts();
4755
4756      if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) {
4757        DiagnoseFloatingLiteralImpCast(S, FL, T, CC);
4758      } else {
4759        DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer);
4760      }
4761    }
4762
4763    // If the target is bool, warn if expr is a function or method call.
4764    if (Target->isSpecificBuiltinType(BuiltinType::Bool) &&
4765        isa<CallExpr>(E)) {
4766      // Check last argument of function call to see if it is an
4767      // implicit cast from a type matching the type the result
4768      // is being cast to.
4769      CallExpr *CEx = cast<CallExpr>(E);
4770      unsigned NumArgs = CEx->getNumArgs();
4771      if (NumArgs > 0) {
4772        Expr *LastA = CEx->getArg(NumArgs - 1);
4773        Expr *InnerE = LastA->IgnoreParenImpCasts();
4774        const Type *InnerType =
4775          S.Context.getCanonicalType(InnerE->getType()).getTypePtr();
4776        if (isa<ImplicitCastExpr>(LastA) && (InnerType == Target)) {
4777          // Warn on this floating-point to bool conversion
4778          DiagnoseImpCast(S, E, T, CC,
4779                          diag::warn_impcast_floating_point_to_bool);
4780        }
4781      }
4782    }
4783    return;
4784  }
4785
4786  if ((E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull)
4787           == Expr::NPCK_GNUNull) && !Target->isAnyPointerType()
4788      && !Target->isBlockPointerType() && !Target->isMemberPointerType()) {
4789    SourceLocation Loc = E->getSourceRange().getBegin();
4790    if (Loc.isMacroID())
4791      Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first;
4792    if (!Loc.isMacroID() || CC.isMacroID())
4793      S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer)
4794          << T << clang::SourceRange(CC)
4795          << FixItHint::CreateReplacement(Loc, S.getFixItZeroLiteralForType(T));
4796  }
4797
4798  if (!Source->isIntegerType() || !Target->isIntegerType())
4799    return;
4800
4801  // TODO: remove this early return once the false positives for constant->bool
4802  // in templates, macros, etc, are reduced or removed.
4803  if (Target->isSpecificBuiltinType(BuiltinType::Bool))
4804    return;
4805
4806  IntRange SourceRange = GetExprRange(S.Context, E);
4807  IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target);
4808
4809  if (SourceRange.Width > TargetRange.Width) {
4810    // If the source is a constant, use a default-on diagnostic.
4811    // TODO: this should happen for bitfield stores, too.
4812    llvm::APSInt Value(32);
4813    if (E->isIntegerConstantExpr(Value, S.Context)) {
4814      if (S.SourceMgr.isInSystemMacro(CC))
4815        return;
4816
4817      std::string PrettySourceValue = Value.toString(10);
4818      std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange);
4819
4820      S.DiagRuntimeBehavior(E->getExprLoc(), E,
4821        S.PDiag(diag::warn_impcast_integer_precision_constant)
4822            << PrettySourceValue << PrettyTargetValue
4823            << E->getType() << T << E->getSourceRange()
4824            << clang::SourceRange(CC));
4825      return;
4826    }
4827
4828    // People want to build with -Wshorten-64-to-32 and not -Wconversion.
4829    if (S.SourceMgr.isInSystemMacro(CC))
4830      return;
4831
4832    if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64)
4833      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32,
4834                             /* pruneControlFlow */ true);
4835    return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision);
4836  }
4837
4838  if ((TargetRange.NonNegative && !SourceRange.NonNegative) ||
4839      (!TargetRange.NonNegative && SourceRange.NonNegative &&
4840       SourceRange.Width == TargetRange.Width)) {
4841
4842    if (S.SourceMgr.isInSystemMacro(CC))
4843      return;
4844
4845    unsigned DiagID = diag::warn_impcast_integer_sign;
4846
4847    // Traditionally, gcc has warned about this under -Wsign-compare.
4848    // We also want to warn about it in -Wconversion.
4849    // So if -Wconversion is off, use a completely identical diagnostic
4850    // in the sign-compare group.
4851    // The conditional-checking code will
4852    if (ICContext) {
4853      DiagID = diag::warn_impcast_integer_sign_conditional;
4854      *ICContext = true;
4855    }
4856
4857    return DiagnoseImpCast(S, E, T, CC, DiagID);
4858  }
4859
4860  // Diagnose conversions between different enumeration types.
4861  // In C, we pretend that the type of an EnumConstantDecl is its enumeration
4862  // type, to give us better diagnostics.
4863  QualType SourceType = E->getType();
4864  if (!S.getLangOpts().CPlusPlus) {
4865    if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
4866      if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) {
4867        EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext());
4868        SourceType = S.Context.getTypeDeclType(Enum);
4869        Source = S.Context.getCanonicalType(SourceType).getTypePtr();
4870      }
4871  }
4872
4873  if (const EnumType *SourceEnum = Source->getAs<EnumType>())
4874    if (const EnumType *TargetEnum = Target->getAs<EnumType>())
4875      if ((SourceEnum->getDecl()->getIdentifier() ||
4876           SourceEnum->getDecl()->getTypedefNameForAnonDecl()) &&
4877          (TargetEnum->getDecl()->getIdentifier() ||
4878           TargetEnum->getDecl()->getTypedefNameForAnonDecl()) &&
4879          SourceEnum != TargetEnum) {
4880        if (S.SourceMgr.isInSystemMacro(CC))
4881          return;
4882
4883        return DiagnoseImpCast(S, E, SourceType, T, CC,
4884                               diag::warn_impcast_different_enum_types);
4885      }
4886
4887  return;
4888}
4889
4890void CheckConditionalOperator(Sema &S, ConditionalOperator *E,
4891                              SourceLocation CC, QualType T);
4892
4893void CheckConditionalOperand(Sema &S, Expr *E, QualType T,
4894                             SourceLocation CC, bool &ICContext) {
4895  E = E->IgnoreParenImpCasts();
4896
4897  if (isa<ConditionalOperator>(E))
4898    return CheckConditionalOperator(S, cast<ConditionalOperator>(E), CC, T);
4899
4900  AnalyzeImplicitConversions(S, E, CC);
4901  if (E->getType() != T)
4902    return CheckImplicitConversion(S, E, T, CC, &ICContext);
4903  return;
4904}
4905
4906void CheckConditionalOperator(Sema &S, ConditionalOperator *E,
4907                              SourceLocation CC, QualType T) {
4908  AnalyzeImplicitConversions(S, E->getCond(), CC);
4909
4910  bool Suspicious = false;
4911  CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious);
4912  CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious);
4913
4914  // If -Wconversion would have warned about either of the candidates
4915  // for a signedness conversion to the context type...
4916  if (!Suspicious) return;
4917
4918  // ...but it's currently ignored...
4919  if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional,
4920                                 CC))
4921    return;
4922
4923  // ...then check whether it would have warned about either of the
4924  // candidates for a signedness conversion to the condition type.
4925  if (E->getType() == T) return;
4926
4927  Suspicious = false;
4928  CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(),
4929                          E->getType(), CC, &Suspicious);
4930  if (!Suspicious)
4931    CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(),
4932                            E->getType(), CC, &Suspicious);
4933}
4934
4935/// AnalyzeImplicitConversions - Find and report any interesting
4936/// implicit conversions in the given expression.  There are a couple
4937/// of competing diagnostics here, -Wconversion and -Wsign-compare.
4938void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) {
4939  QualType T = OrigE->getType();
4940  Expr *E = OrigE->IgnoreParenImpCasts();
4941
4942  if (E->isTypeDependent() || E->isValueDependent())
4943    return;
4944
4945  // For conditional operators, we analyze the arguments as if they
4946  // were being fed directly into the output.
4947  if (isa<ConditionalOperator>(E)) {
4948    ConditionalOperator *CO = cast<ConditionalOperator>(E);
4949    CheckConditionalOperator(S, CO, CC, T);
4950    return;
4951  }
4952
4953  // Check implicit argument conversions for function calls.
4954  if (CallExpr *Call = dyn_cast<CallExpr>(E))
4955    CheckImplicitArgumentConversions(S, Call, CC);
4956
4957  // Go ahead and check any implicit conversions we might have skipped.
4958  // The non-canonical typecheck is just an optimization;
4959  // CheckImplicitConversion will filter out dead implicit conversions.
4960  if (E->getType() != T)
4961    CheckImplicitConversion(S, E, T, CC);
4962
4963  // Now continue drilling into this expression.
4964
4965  // Skip past explicit casts.
4966  if (isa<ExplicitCastExpr>(E)) {
4967    E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts();
4968    return AnalyzeImplicitConversions(S, E, CC);
4969  }
4970
4971  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
4972    // Do a somewhat different check with comparison operators.
4973    if (BO->isComparisonOp())
4974      return AnalyzeComparison(S, BO);
4975
4976    // And with simple assignments.
4977    if (BO->getOpcode() == BO_Assign)
4978      return AnalyzeAssignment(S, BO);
4979  }
4980
4981  // These break the otherwise-useful invariant below.  Fortunately,
4982  // we don't really need to recurse into them, because any internal
4983  // expressions should have been analyzed already when they were
4984  // built into statements.
4985  if (isa<StmtExpr>(E)) return;
4986
4987  // Don't descend into unevaluated contexts.
4988  if (isa<UnaryExprOrTypeTraitExpr>(E)) return;
4989
4990  // Now just recurse over the expression's children.
4991  CC = E->getExprLoc();
4992  BinaryOperator *BO = dyn_cast<BinaryOperator>(E);
4993  bool IsLogicalOperator = BO && BO->isLogicalOp();
4994  for (Stmt::child_range I = E->children(); I; ++I) {
4995    Expr *ChildExpr = dyn_cast_or_null<Expr>(*I);
4996    if (!ChildExpr)
4997      continue;
4998
4999    if (IsLogicalOperator &&
5000        isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts()))
5001      // Ignore checking string literals that are in logical operators.
5002      continue;
5003    AnalyzeImplicitConversions(S, ChildExpr, CC);
5004  }
5005}
5006
5007} // end anonymous namespace
5008
5009/// Diagnoses "dangerous" implicit conversions within the given
5010/// expression (which is a full expression).  Implements -Wconversion
5011/// and -Wsign-compare.
5012///
5013/// \param CC the "context" location of the implicit conversion, i.e.
5014///   the most location of the syntactic entity requiring the implicit
5015///   conversion
5016void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) {
5017  // Don't diagnose in unevaluated contexts.
5018  if (isUnevaluatedContext())
5019    return;
5020
5021  // Don't diagnose for value- or type-dependent expressions.
5022  if (E->isTypeDependent() || E->isValueDependent())
5023    return;
5024
5025  // Check for array bounds violations in cases where the check isn't triggered
5026  // elsewhere for other Expr types (like BinaryOperators), e.g. when an
5027  // ArraySubscriptExpr is on the RHS of a variable initialization.
5028  CheckArrayAccess(E);
5029
5030  // This is not the right CC for (e.g.) a variable initialization.
5031  AnalyzeImplicitConversions(*this, E, CC);
5032}
5033
5034void Sema::CheckBitFieldInitialization(SourceLocation InitLoc,
5035                                       FieldDecl *BitField,
5036                                       Expr *Init) {
5037  (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc);
5038}
5039
5040/// CheckParmsForFunctionDef - Check that the parameters of the given
5041/// function are appropriate for the definition of a function. This
5042/// takes care of any checks that cannot be performed on the
5043/// declaration itself, e.g., that the types of each of the function
5044/// parameters are complete.
5045bool Sema::CheckParmsForFunctionDef(ParmVarDecl **P, ParmVarDecl **PEnd,
5046                                    bool CheckParameterNames) {
5047  bool HasInvalidParm = false;
5048  for (; P != PEnd; ++P) {
5049    ParmVarDecl *Param = *P;
5050
5051    // C99 6.7.5.3p4: the parameters in a parameter type list in a
5052    // function declarator that is part of a function definition of
5053    // that function shall not have incomplete type.
5054    //
5055    // This is also C++ [dcl.fct]p6.
5056    if (!Param->isInvalidDecl() &&
5057        RequireCompleteType(Param->getLocation(), Param->getType(),
5058                            diag::err_typecheck_decl_incomplete_type)) {
5059      Param->setInvalidDecl();
5060      HasInvalidParm = true;
5061    }
5062
5063    // C99 6.9.1p5: If the declarator includes a parameter type list, the
5064    // declaration of each parameter shall include an identifier.
5065    if (CheckParameterNames &&
5066        Param->getIdentifier() == 0 &&
5067        !Param->isImplicit() &&
5068        !getLangOpts().CPlusPlus)
5069      Diag(Param->getLocation(), diag::err_parameter_name_omitted);
5070
5071    // C99 6.7.5.3p12:
5072    //   If the function declarator is not part of a definition of that
5073    //   function, parameters may have incomplete type and may use the [*]
5074    //   notation in their sequences of declarator specifiers to specify
5075    //   variable length array types.
5076    QualType PType = Param->getOriginalType();
5077    if (const ArrayType *AT = Context.getAsArrayType(PType)) {
5078      if (AT->getSizeModifier() == ArrayType::Star) {
5079        // FIXME: This diagnosic should point the '[*]' if source-location
5080        // information is added for it.
5081        Diag(Param->getLocation(), diag::err_array_star_in_function_definition);
5082      }
5083    }
5084  }
5085
5086  return HasInvalidParm;
5087}
5088
5089/// CheckCastAlign - Implements -Wcast-align, which warns when a
5090/// pointer cast increases the alignment requirements.
5091void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) {
5092  // This is actually a lot of work to potentially be doing on every
5093  // cast; don't do it if we're ignoring -Wcast_align (as is the default).
5094  if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align,
5095                                          TRange.getBegin())
5096        == DiagnosticsEngine::Ignored)
5097    return;
5098
5099  // Ignore dependent types.
5100  if (T->isDependentType() || Op->getType()->isDependentType())
5101    return;
5102
5103  // Require that the destination be a pointer type.
5104  const PointerType *DestPtr = T->getAs<PointerType>();
5105  if (!DestPtr) return;
5106
5107  // If the destination has alignment 1, we're done.
5108  QualType DestPointee = DestPtr->getPointeeType();
5109  if (DestPointee->isIncompleteType()) return;
5110  CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee);
5111  if (DestAlign.isOne()) return;
5112
5113  // Require that the source be a pointer type.
5114  const PointerType *SrcPtr = Op->getType()->getAs<PointerType>();
5115  if (!SrcPtr) return;
5116  QualType SrcPointee = SrcPtr->getPointeeType();
5117
5118  // Whitelist casts from cv void*.  We already implicitly
5119  // whitelisted casts to cv void*, since they have alignment 1.
5120  // Also whitelist casts involving incomplete types, which implicitly
5121  // includes 'void'.
5122  if (SrcPointee->isIncompleteType()) return;
5123
5124  CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee);
5125  if (SrcAlign >= DestAlign) return;
5126
5127  Diag(TRange.getBegin(), diag::warn_cast_align)
5128    << Op->getType() << T
5129    << static_cast<unsigned>(SrcAlign.getQuantity())
5130    << static_cast<unsigned>(DestAlign.getQuantity())
5131    << TRange << Op->getSourceRange();
5132}
5133
5134static const Type* getElementType(const Expr *BaseExpr) {
5135  const Type* EltType = BaseExpr->getType().getTypePtr();
5136  if (EltType->isAnyPointerType())
5137    return EltType->getPointeeType().getTypePtr();
5138  else if (EltType->isArrayType())
5139    return EltType->getBaseElementTypeUnsafe();
5140  return EltType;
5141}
5142
5143/// \brief Check whether this array fits the idiom of a size-one tail padded
5144/// array member of a struct.
5145///
5146/// We avoid emitting out-of-bounds access warnings for such arrays as they are
5147/// commonly used to emulate flexible arrays in C89 code.
5148static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size,
5149                                    const NamedDecl *ND) {
5150  if (Size != 1 || !ND) return false;
5151
5152  const FieldDecl *FD = dyn_cast<FieldDecl>(ND);
5153  if (!FD) return false;
5154
5155  // Don't consider sizes resulting from macro expansions or template argument
5156  // substitution to form C89 tail-padded arrays.
5157
5158  TypeSourceInfo *TInfo = FD->getTypeSourceInfo();
5159  while (TInfo) {
5160    TypeLoc TL = TInfo->getTypeLoc();
5161    // Look through typedefs.
5162    const TypedefTypeLoc *TTL = dyn_cast<TypedefTypeLoc>(&TL);
5163    if (TTL) {
5164      const TypedefNameDecl *TDL = TTL->getTypedefNameDecl();
5165      TInfo = TDL->getTypeSourceInfo();
5166      continue;
5167    }
5168    ConstantArrayTypeLoc CTL = cast<ConstantArrayTypeLoc>(TL);
5169    const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr());
5170    if (!SizeExpr || SizeExpr->getExprLoc().isMacroID())
5171      return false;
5172    break;
5173  }
5174
5175  const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext());
5176  if (!RD) return false;
5177  if (RD->isUnion()) return false;
5178  if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
5179    if (!CRD->isStandardLayout()) return false;
5180  }
5181
5182  // See if this is the last field decl in the record.
5183  const Decl *D = FD;
5184  while ((D = D->getNextDeclInContext()))
5185    if (isa<FieldDecl>(D))
5186      return false;
5187  return true;
5188}
5189
5190void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr,
5191                            const ArraySubscriptExpr *ASE,
5192                            bool AllowOnePastEnd, bool IndexNegated) {
5193  IndexExpr = IndexExpr->IgnoreParenImpCasts();
5194  if (IndexExpr->isValueDependent())
5195    return;
5196
5197  const Type *EffectiveType = getElementType(BaseExpr);
5198  BaseExpr = BaseExpr->IgnoreParenCasts();
5199  const ConstantArrayType *ArrayTy =
5200    Context.getAsConstantArrayType(BaseExpr->getType());
5201  if (!ArrayTy)
5202    return;
5203
5204  llvm::APSInt index;
5205  if (!IndexExpr->EvaluateAsInt(index, Context))
5206    return;
5207  if (IndexNegated)
5208    index = -index;
5209
5210  const NamedDecl *ND = NULL;
5211  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))
5212    ND = dyn_cast<NamedDecl>(DRE->getDecl());
5213  if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr))
5214    ND = dyn_cast<NamedDecl>(ME->getMemberDecl());
5215
5216  if (index.isUnsigned() || !index.isNegative()) {
5217    llvm::APInt size = ArrayTy->getSize();
5218    if (!size.isStrictlyPositive())
5219      return;
5220
5221    const Type* BaseType = getElementType(BaseExpr);
5222    if (BaseType != EffectiveType) {
5223      // Make sure we're comparing apples to apples when comparing index to size
5224      uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType);
5225      uint64_t array_typesize = Context.getTypeSize(BaseType);
5226      // Handle ptrarith_typesize being zero, such as when casting to void*
5227      if (!ptrarith_typesize) ptrarith_typesize = 1;
5228      if (ptrarith_typesize != array_typesize) {
5229        // There's a cast to a different size type involved
5230        uint64_t ratio = array_typesize / ptrarith_typesize;
5231        // TODO: Be smarter about handling cases where array_typesize is not a
5232        // multiple of ptrarith_typesize
5233        if (ptrarith_typesize * ratio == array_typesize)
5234          size *= llvm::APInt(size.getBitWidth(), ratio);
5235      }
5236    }
5237
5238    if (size.getBitWidth() > index.getBitWidth())
5239      index = index.zext(size.getBitWidth());
5240    else if (size.getBitWidth() < index.getBitWidth())
5241      size = size.zext(index.getBitWidth());
5242
5243    // For array subscripting the index must be less than size, but for pointer
5244    // arithmetic also allow the index (offset) to be equal to size since
5245    // computing the next address after the end of the array is legal and
5246    // commonly done e.g. in C++ iterators and range-based for loops.
5247    if (AllowOnePastEnd ? index.ule(size) : index.ult(size))
5248      return;
5249
5250    // Also don't warn for arrays of size 1 which are members of some
5251    // structure. These are often used to approximate flexible arrays in C89
5252    // code.
5253    if (IsTailPaddedMemberArray(*this, size, ND))
5254      return;
5255
5256    // Suppress the warning if the subscript expression (as identified by the
5257    // ']' location) and the index expression are both from macro expansions
5258    // within a system header.
5259    if (ASE) {
5260      SourceLocation RBracketLoc = SourceMgr.getSpellingLoc(
5261          ASE->getRBracketLoc());
5262      if (SourceMgr.isInSystemHeader(RBracketLoc)) {
5263        SourceLocation IndexLoc = SourceMgr.getSpellingLoc(
5264            IndexExpr->getLocStart());
5265        if (SourceMgr.isFromSameFile(RBracketLoc, IndexLoc))
5266          return;
5267      }
5268    }
5269
5270    unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds;
5271    if (ASE)
5272      DiagID = diag::warn_array_index_exceeds_bounds;
5273
5274    DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr,
5275                        PDiag(DiagID) << index.toString(10, true)
5276                          << size.toString(10, true)
5277                          << (unsigned)size.getLimitedValue(~0U)
5278                          << IndexExpr->getSourceRange());
5279  } else {
5280    unsigned DiagID = diag::warn_array_index_precedes_bounds;
5281    if (!ASE) {
5282      DiagID = diag::warn_ptr_arith_precedes_bounds;
5283      if (index.isNegative()) index = -index;
5284    }
5285
5286    DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr,
5287                        PDiag(DiagID) << index.toString(10, true)
5288                          << IndexExpr->getSourceRange());
5289  }
5290
5291  if (!ND) {
5292    // Try harder to find a NamedDecl to point at in the note.
5293    while (const ArraySubscriptExpr *ASE =
5294           dyn_cast<ArraySubscriptExpr>(BaseExpr))
5295      BaseExpr = ASE->getBase()->IgnoreParenCasts();
5296    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))
5297      ND = dyn_cast<NamedDecl>(DRE->getDecl());
5298    if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr))
5299      ND = dyn_cast<NamedDecl>(ME->getMemberDecl());
5300  }
5301
5302  if (ND)
5303    DiagRuntimeBehavior(ND->getLocStart(), BaseExpr,
5304                        PDiag(diag::note_array_index_out_of_bounds)
5305                          << ND->getDeclName());
5306}
5307
5308void Sema::CheckArrayAccess(const Expr *expr) {
5309  int AllowOnePastEnd = 0;
5310  while (expr) {
5311    expr = expr->IgnoreParenImpCasts();
5312    switch (expr->getStmtClass()) {
5313      case Stmt::ArraySubscriptExprClass: {
5314        const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr);
5315        CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE,
5316                         AllowOnePastEnd > 0);
5317        return;
5318      }
5319      case Stmt::UnaryOperatorClass: {
5320        // Only unwrap the * and & unary operators
5321        const UnaryOperator *UO = cast<UnaryOperator>(expr);
5322        expr = UO->getSubExpr();
5323        switch (UO->getOpcode()) {
5324          case UO_AddrOf:
5325            AllowOnePastEnd++;
5326            break;
5327          case UO_Deref:
5328            AllowOnePastEnd--;
5329            break;
5330          default:
5331            return;
5332        }
5333        break;
5334      }
5335      case Stmt::ConditionalOperatorClass: {
5336        const ConditionalOperator *cond = cast<ConditionalOperator>(expr);
5337        if (const Expr *lhs = cond->getLHS())
5338          CheckArrayAccess(lhs);
5339        if (const Expr *rhs = cond->getRHS())
5340          CheckArrayAccess(rhs);
5341        return;
5342      }
5343      default:
5344        return;
5345    }
5346  }
5347}
5348
5349//===--- CHECK: Objective-C retain cycles ----------------------------------//
5350
5351namespace {
5352  struct RetainCycleOwner {
5353    RetainCycleOwner() : Variable(0), Indirect(false) {}
5354    VarDecl *Variable;
5355    SourceRange Range;
5356    SourceLocation Loc;
5357    bool Indirect;
5358
5359    void setLocsFrom(Expr *e) {
5360      Loc = e->getExprLoc();
5361      Range = e->getSourceRange();
5362    }
5363  };
5364}
5365
5366/// Consider whether capturing the given variable can possibly lead to
5367/// a retain cycle.
5368static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) {
5369  // In ARC, it's captured strongly if the variable has __strong
5370  // lifetime.  In MRR, it's captured strongly if the variable is
5371  // __block and has an appropriate type.
5372  if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
5373    return false;
5374
5375  owner.Variable = var;
5376  if (ref)
5377    owner.setLocsFrom(ref);
5378  return true;
5379}
5380
5381static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) {
5382  while (true) {
5383    e = e->IgnoreParens();
5384    if (CastExpr *cast = dyn_cast<CastExpr>(e)) {
5385      switch (cast->getCastKind()) {
5386      case CK_BitCast:
5387      case CK_LValueBitCast:
5388      case CK_LValueToRValue:
5389      case CK_ARCReclaimReturnedObject:
5390        e = cast->getSubExpr();
5391        continue;
5392
5393      default:
5394        return false;
5395      }
5396    }
5397
5398    if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) {
5399      ObjCIvarDecl *ivar = ref->getDecl();
5400      if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
5401        return false;
5402
5403      // Try to find a retain cycle in the base.
5404      if (!findRetainCycleOwner(S, ref->getBase(), owner))
5405        return false;
5406
5407      if (ref->isFreeIvar()) owner.setLocsFrom(ref);
5408      owner.Indirect = true;
5409      return true;
5410    }
5411
5412    if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) {
5413      VarDecl *var = dyn_cast<VarDecl>(ref->getDecl());
5414      if (!var) return false;
5415      return considerVariable(var, ref, owner);
5416    }
5417
5418    if (MemberExpr *member = dyn_cast<MemberExpr>(e)) {
5419      if (member->isArrow()) return false;
5420
5421      // Don't count this as an indirect ownership.
5422      e = member->getBase();
5423      continue;
5424    }
5425
5426    if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) {
5427      // Only pay attention to pseudo-objects on property references.
5428      ObjCPropertyRefExpr *pre
5429        = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm()
5430                                              ->IgnoreParens());
5431      if (!pre) return false;
5432      if (pre->isImplicitProperty()) return false;
5433      ObjCPropertyDecl *property = pre->getExplicitProperty();
5434      if (!property->isRetaining() &&
5435          !(property->getPropertyIvarDecl() &&
5436            property->getPropertyIvarDecl()->getType()
5437              .getObjCLifetime() == Qualifiers::OCL_Strong))
5438          return false;
5439
5440      owner.Indirect = true;
5441      if (pre->isSuperReceiver()) {
5442        owner.Variable = S.getCurMethodDecl()->getSelfDecl();
5443        if (!owner.Variable)
5444          return false;
5445        owner.Loc = pre->getLocation();
5446        owner.Range = pre->getSourceRange();
5447        return true;
5448      }
5449      e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase())
5450                              ->getSourceExpr());
5451      continue;
5452    }
5453
5454    // Array ivars?
5455
5456    return false;
5457  }
5458}
5459
5460namespace {
5461  struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> {
5462    FindCaptureVisitor(ASTContext &Context, VarDecl *variable)
5463      : EvaluatedExprVisitor<FindCaptureVisitor>(Context),
5464        Variable(variable), Capturer(0) {}
5465
5466    VarDecl *Variable;
5467    Expr *Capturer;
5468
5469    void VisitDeclRefExpr(DeclRefExpr *ref) {
5470      if (ref->getDecl() == Variable && !Capturer)
5471        Capturer = ref;
5472    }
5473
5474    void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) {
5475      if (Capturer) return;
5476      Visit(ref->getBase());
5477      if (Capturer && ref->isFreeIvar())
5478        Capturer = ref;
5479    }
5480
5481    void VisitBlockExpr(BlockExpr *block) {
5482      // Look inside nested blocks
5483      if (block->getBlockDecl()->capturesVariable(Variable))
5484        Visit(block->getBlockDecl()->getBody());
5485    }
5486
5487    void VisitOpaqueValueExpr(OpaqueValueExpr *OVE) {
5488      if (Capturer) return;
5489      if (OVE->getSourceExpr())
5490        Visit(OVE->getSourceExpr());
5491    }
5492  };
5493}
5494
5495/// Check whether the given argument is a block which captures a
5496/// variable.
5497static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) {
5498  assert(owner.Variable && owner.Loc.isValid());
5499
5500  e = e->IgnoreParenCasts();
5501
5502  // Look through [^{...} copy] and Block_copy(^{...}).
5503  if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(e)) {
5504    Selector Cmd = ME->getSelector();
5505    if (Cmd.isUnarySelector() && Cmd.getNameForSlot(0) == "copy") {
5506      e = ME->getInstanceReceiver();
5507      if (!e)
5508        return 0;
5509      e = e->IgnoreParenCasts();
5510    }
5511  } else if (CallExpr *CE = dyn_cast<CallExpr>(e)) {
5512    if (CE->getNumArgs() == 1) {
5513      FunctionDecl *Fn = dyn_cast_or_null<FunctionDecl>(CE->getCalleeDecl());
5514      if (Fn && Fn->getIdentifier()->isStr("_Block_copy"))
5515        e = CE->getArg(0)->IgnoreParenCasts();
5516    }
5517  }
5518
5519  BlockExpr *block = dyn_cast<BlockExpr>(e);
5520  if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable))
5521    return 0;
5522
5523  FindCaptureVisitor visitor(S.Context, owner.Variable);
5524  visitor.Visit(block->getBlockDecl()->getBody());
5525  return visitor.Capturer;
5526}
5527
5528static void diagnoseRetainCycle(Sema &S, Expr *capturer,
5529                                RetainCycleOwner &owner) {
5530  assert(capturer);
5531  assert(owner.Variable && owner.Loc.isValid());
5532
5533  S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle)
5534    << owner.Variable << capturer->getSourceRange();
5535  S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner)
5536    << owner.Indirect << owner.Range;
5537}
5538
5539/// Check for a keyword selector that starts with the word 'add' or
5540/// 'set'.
5541static bool isSetterLikeSelector(Selector sel) {
5542  if (sel.isUnarySelector()) return false;
5543
5544  StringRef str = sel.getNameForSlot(0);
5545  while (!str.empty() && str.front() == '_') str = str.substr(1);
5546  if (str.startswith("set"))
5547    str = str.substr(3);
5548  else if (str.startswith("add")) {
5549    // Specially whitelist 'addOperationWithBlock:'.
5550    if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock"))
5551      return false;
5552    str = str.substr(3);
5553  }
5554  else
5555    return false;
5556
5557  if (str.empty()) return true;
5558  return !islower(str.front());
5559}
5560
5561/// Check a message send to see if it's likely to cause a retain cycle.
5562void Sema::checkRetainCycles(ObjCMessageExpr *msg) {
5563  // Only check instance methods whose selector looks like a setter.
5564  if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector()))
5565    return;
5566
5567  // Try to find a variable that the receiver is strongly owned by.
5568  RetainCycleOwner owner;
5569  if (msg->getReceiverKind() == ObjCMessageExpr::Instance) {
5570    if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner))
5571      return;
5572  } else {
5573    assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance);
5574    owner.Variable = getCurMethodDecl()->getSelfDecl();
5575    owner.Loc = msg->getSuperLoc();
5576    owner.Range = msg->getSuperLoc();
5577  }
5578
5579  // Check whether the receiver is captured by any of the arguments.
5580  for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i)
5581    if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner))
5582      return diagnoseRetainCycle(*this, capturer, owner);
5583}
5584
5585/// Check a property assign to see if it's likely to cause a retain cycle.
5586void Sema::checkRetainCycles(Expr *receiver, Expr *argument) {
5587  RetainCycleOwner owner;
5588  if (!findRetainCycleOwner(*this, receiver, owner))
5589    return;
5590
5591  if (Expr *capturer = findCapturingExpr(*this, argument, owner))
5592    diagnoseRetainCycle(*this, capturer, owner);
5593}
5594
5595void Sema::checkRetainCycles(VarDecl *Var, Expr *Init) {
5596  RetainCycleOwner Owner;
5597  if (!considerVariable(Var, /*DeclRefExpr=*/0, Owner))
5598    return;
5599
5600  // Because we don't have an expression for the variable, we have to set the
5601  // location explicitly here.
5602  Owner.Loc = Var->getLocation();
5603  Owner.Range = Var->getSourceRange();
5604
5605  if (Expr *Capturer = findCapturingExpr(*this, Init, Owner))
5606    diagnoseRetainCycle(*this, Capturer, Owner);
5607}
5608
5609bool Sema::checkUnsafeAssigns(SourceLocation Loc,
5610                              QualType LHS, Expr *RHS) {
5611  Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime();
5612  if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone)
5613    return false;
5614  // strip off any implicit cast added to get to the one arc-specific
5615  while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) {
5616    if (cast->getCastKind() == CK_ARCConsumeObject) {
5617      Diag(Loc, diag::warn_arc_retained_assign)
5618        << (LT == Qualifiers::OCL_ExplicitNone) << 1
5619        << RHS->getSourceRange();
5620      return true;
5621    }
5622    RHS = cast->getSubExpr();
5623  }
5624  return false;
5625}
5626
5627void Sema::checkUnsafeExprAssigns(SourceLocation Loc,
5628                              Expr *LHS, Expr *RHS) {
5629  QualType LHSType;
5630  // PropertyRef on LHS type need be directly obtained from
5631  // its declaration as it has a PsuedoType.
5632  ObjCPropertyRefExpr *PRE
5633    = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens());
5634  if (PRE && !PRE->isImplicitProperty()) {
5635    const ObjCPropertyDecl *PD = PRE->getExplicitProperty();
5636    if (PD)
5637      LHSType = PD->getType();
5638  }
5639
5640  if (LHSType.isNull())
5641    LHSType = LHS->getType();
5642  if (checkUnsafeAssigns(Loc, LHSType, RHS))
5643    return;
5644  Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime();
5645  // FIXME. Check for other life times.
5646  if (LT != Qualifiers::OCL_None)
5647    return;
5648
5649  if (PRE) {
5650    if (PRE->isImplicitProperty())
5651      return;
5652    const ObjCPropertyDecl *PD = PRE->getExplicitProperty();
5653    if (!PD)
5654      return;
5655
5656    unsigned Attributes = PD->getPropertyAttributes();
5657    if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) {
5658      // when 'assign' attribute was not explicitly specified
5659      // by user, ignore it and rely on property type itself
5660      // for lifetime info.
5661      unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten();
5662      if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) &&
5663          LHSType->isObjCRetainableType())
5664        return;
5665
5666      while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) {
5667        if (cast->getCastKind() == CK_ARCConsumeObject) {
5668          Diag(Loc, diag::warn_arc_retained_property_assign)
5669          << RHS->getSourceRange();
5670          return;
5671        }
5672        RHS = cast->getSubExpr();
5673      }
5674    }
5675    else if (Attributes & ObjCPropertyDecl::OBJC_PR_weak) {
5676      while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) {
5677        if (cast->getCastKind() == CK_ARCConsumeObject) {
5678          Diag(Loc, diag::warn_arc_retained_assign)
5679          << 0 << 0<< RHS->getSourceRange();
5680          return;
5681        }
5682        RHS = cast->getSubExpr();
5683      }
5684    }
5685  }
5686}
5687
5688//===--- CHECK: Empty statement body (-Wempty-body) ---------------------===//
5689
5690namespace {
5691bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr,
5692                                 SourceLocation StmtLoc,
5693                                 const NullStmt *Body) {
5694  // Do not warn if the body is a macro that expands to nothing, e.g:
5695  //
5696  // #define CALL(x)
5697  // if (condition)
5698  //   CALL(0);
5699  //
5700  if (Body->hasLeadingEmptyMacro())
5701    return false;
5702
5703  // Get line numbers of statement and body.
5704  bool StmtLineInvalid;
5705  unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc,
5706                                                      &StmtLineInvalid);
5707  if (StmtLineInvalid)
5708    return false;
5709
5710  bool BodyLineInvalid;
5711  unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(),
5712                                                      &BodyLineInvalid);
5713  if (BodyLineInvalid)
5714    return false;
5715
5716  // Warn if null statement and body are on the same line.
5717  if (StmtLine != BodyLine)
5718    return false;
5719
5720  return true;
5721}
5722} // Unnamed namespace
5723
5724void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc,
5725                                 const Stmt *Body,
5726                                 unsigned DiagID) {
5727  // Since this is a syntactic check, don't emit diagnostic for template
5728  // instantiations, this just adds noise.
5729  if (CurrentInstantiationScope)
5730    return;
5731
5732  // The body should be a null statement.
5733  const NullStmt *NBody = dyn_cast<NullStmt>(Body);
5734  if (!NBody)
5735    return;
5736
5737  // Do the usual checks.
5738  if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody))
5739    return;
5740
5741  Diag(NBody->getSemiLoc(), DiagID);
5742  Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line);
5743}
5744
5745void Sema::DiagnoseEmptyLoopBody(const Stmt *S,
5746                                 const Stmt *PossibleBody) {
5747  assert(!CurrentInstantiationScope); // Ensured by caller
5748
5749  SourceLocation StmtLoc;
5750  const Stmt *Body;
5751  unsigned DiagID;
5752  if (const ForStmt *FS = dyn_cast<ForStmt>(S)) {
5753    StmtLoc = FS->getRParenLoc();
5754    Body = FS->getBody();
5755    DiagID = diag::warn_empty_for_body;
5756  } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) {
5757    StmtLoc = WS->getCond()->getSourceRange().getEnd();
5758    Body = WS->getBody();
5759    DiagID = diag::warn_empty_while_body;
5760  } else
5761    return; // Neither `for' nor `while'.
5762
5763  // The body should be a null statement.
5764  const NullStmt *NBody = dyn_cast<NullStmt>(Body);
5765  if (!NBody)
5766    return;
5767
5768  // Skip expensive checks if diagnostic is disabled.
5769  if (Diags.getDiagnosticLevel(DiagID, NBody->getSemiLoc()) ==
5770          DiagnosticsEngine::Ignored)
5771    return;
5772
5773  // Do the usual checks.
5774  if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody))
5775    return;
5776
5777  // `for(...);' and `while(...);' are popular idioms, so in order to keep
5778  // noise level low, emit diagnostics only if for/while is followed by a
5779  // CompoundStmt, e.g.:
5780  //    for (int i = 0; i < n; i++);
5781  //    {
5782  //      a(i);
5783  //    }
5784  // or if for/while is followed by a statement with more indentation
5785  // than for/while itself:
5786  //    for (int i = 0; i < n; i++);
5787  //      a(i);
5788  bool ProbableTypo = isa<CompoundStmt>(PossibleBody);
5789  if (!ProbableTypo) {
5790    bool BodyColInvalid;
5791    unsigned BodyCol = SourceMgr.getPresumedColumnNumber(
5792                             PossibleBody->getLocStart(),
5793                             &BodyColInvalid);
5794    if (BodyColInvalid)
5795      return;
5796
5797    bool StmtColInvalid;
5798    unsigned StmtCol = SourceMgr.getPresumedColumnNumber(
5799                             S->getLocStart(),
5800                             &StmtColInvalid);
5801    if (StmtColInvalid)
5802      return;
5803
5804    if (BodyCol > StmtCol)
5805      ProbableTypo = true;
5806  }
5807
5808  if (ProbableTypo) {
5809    Diag(NBody->getSemiLoc(), DiagID);
5810    Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line);
5811  }
5812}
5813
5814//===--- Layout compatibility ----------------------------------------------//
5815
5816namespace {
5817
5818bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2);
5819
5820/// \brief Check if two enumeration types are layout-compatible.
5821bool isLayoutCompatible(ASTContext &C, EnumDecl *ED1, EnumDecl *ED2) {
5822  // C++11 [dcl.enum] p8:
5823  // Two enumeration types are layout-compatible if they have the same
5824  // underlying type.
5825  return ED1->isComplete() && ED2->isComplete() &&
5826         C.hasSameType(ED1->getIntegerType(), ED2->getIntegerType());
5827}
5828
5829/// \brief Check if two fields are layout-compatible.
5830bool isLayoutCompatible(ASTContext &C, FieldDecl *Field1, FieldDecl *Field2) {
5831  if (!isLayoutCompatible(C, Field1->getType(), Field2->getType()))
5832    return false;
5833
5834  if (Field1->isBitField() != Field2->isBitField())
5835    return false;
5836
5837  if (Field1->isBitField()) {
5838    // Make sure that the bit-fields are the same length.
5839    unsigned Bits1 = Field1->getBitWidthValue(C);
5840    unsigned Bits2 = Field2->getBitWidthValue(C);
5841
5842    if (Bits1 != Bits2)
5843      return false;
5844  }
5845
5846  return true;
5847}
5848
5849/// \brief Check if two standard-layout structs are layout-compatible.
5850/// (C++11 [class.mem] p17)
5851bool isLayoutCompatibleStruct(ASTContext &C,
5852                              RecordDecl *RD1,
5853                              RecordDecl *RD2) {
5854  // If both records are C++ classes, check that base classes match.
5855  if (const CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(RD1)) {
5856    // If one of records is a CXXRecordDecl we are in C++ mode,
5857    // thus the other one is a CXXRecordDecl, too.
5858    const CXXRecordDecl *D2CXX = cast<CXXRecordDecl>(RD2);
5859    // Check number of base classes.
5860    if (D1CXX->getNumBases() != D2CXX->getNumBases())
5861      return false;
5862
5863    // Check the base classes.
5864    for (CXXRecordDecl::base_class_const_iterator
5865               Base1 = D1CXX->bases_begin(),
5866           BaseEnd1 = D1CXX->bases_end(),
5867              Base2 = D2CXX->bases_begin();
5868         Base1 != BaseEnd1;
5869         ++Base1, ++Base2) {
5870      if (!isLayoutCompatible(C, Base1->getType(), Base2->getType()))
5871        return false;
5872    }
5873  } else if (const CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(RD2)) {
5874    // If only RD2 is a C++ class, it should have zero base classes.
5875    if (D2CXX->getNumBases() > 0)
5876      return false;
5877  }
5878
5879  // Check the fields.
5880  RecordDecl::field_iterator Field2 = RD2->field_begin(),
5881                             Field2End = RD2->field_end(),
5882                             Field1 = RD1->field_begin(),
5883                             Field1End = RD1->field_end();
5884  for ( ; Field1 != Field1End && Field2 != Field2End; ++Field1, ++Field2) {
5885    if (!isLayoutCompatible(C, *Field1, *Field2))
5886      return false;
5887  }
5888  if (Field1 != Field1End || Field2 != Field2End)
5889    return false;
5890
5891  return true;
5892}
5893
5894/// \brief Check if two standard-layout unions are layout-compatible.
5895/// (C++11 [class.mem] p18)
5896bool isLayoutCompatibleUnion(ASTContext &C,
5897                             RecordDecl *RD1,
5898                             RecordDecl *RD2) {
5899  llvm::SmallPtrSet<FieldDecl *, 8> UnmatchedFields;
5900  for (RecordDecl::field_iterator Field2 = RD2->field_begin(),
5901                                  Field2End = RD2->field_end();
5902       Field2 != Field2End; ++Field2) {
5903    UnmatchedFields.insert(*Field2);
5904  }
5905
5906  for (RecordDecl::field_iterator Field1 = RD1->field_begin(),
5907                                  Field1End = RD1->field_end();
5908       Field1 != Field1End; ++Field1) {
5909    llvm::SmallPtrSet<FieldDecl *, 8>::iterator
5910        I = UnmatchedFields.begin(),
5911        E = UnmatchedFields.end();
5912
5913    for ( ; I != E; ++I) {
5914      if (isLayoutCompatible(C, *Field1, *I)) {
5915        bool Result = UnmatchedFields.erase(*I);
5916        (void) Result;
5917        assert(Result);
5918        break;
5919      }
5920    }
5921    if (I == E)
5922      return false;
5923  }
5924
5925  return UnmatchedFields.empty();
5926}
5927
5928bool isLayoutCompatible(ASTContext &C, RecordDecl *RD1, RecordDecl *RD2) {
5929  if (RD1->isUnion() != RD2->isUnion())
5930    return false;
5931
5932  if (RD1->isUnion())
5933    return isLayoutCompatibleUnion(C, RD1, RD2);
5934  else
5935    return isLayoutCompatibleStruct(C, RD1, RD2);
5936}
5937
5938/// \brief Check if two types are layout-compatible in C++11 sense.
5939bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2) {
5940  if (T1.isNull() || T2.isNull())
5941    return false;
5942
5943  // C++11 [basic.types] p11:
5944  // If two types T1 and T2 are the same type, then T1 and T2 are
5945  // layout-compatible types.
5946  if (C.hasSameType(T1, T2))
5947    return true;
5948
5949  T1 = T1.getCanonicalType().getUnqualifiedType();
5950  T2 = T2.getCanonicalType().getUnqualifiedType();
5951
5952  const Type::TypeClass TC1 = T1->getTypeClass();
5953  const Type::TypeClass TC2 = T2->getTypeClass();
5954
5955  if (TC1 != TC2)
5956    return false;
5957
5958  if (TC1 == Type::Enum) {
5959    return isLayoutCompatible(C,
5960                              cast<EnumType>(T1)->getDecl(),
5961                              cast<EnumType>(T2)->getDecl());
5962  } else if (TC1 == Type::Record) {
5963    if (!T1->isStandardLayoutType() || !T2->isStandardLayoutType())
5964      return false;
5965
5966    return isLayoutCompatible(C,
5967                              cast<RecordType>(T1)->getDecl(),
5968                              cast<RecordType>(T2)->getDecl());
5969  }
5970
5971  return false;
5972}
5973}
5974
5975//===--- CHECK: pointer_with_type_tag attribute: datatypes should match ----//
5976
5977namespace {
5978/// \brief Given a type tag expression find the type tag itself.
5979///
5980/// \param TypeExpr Type tag expression, as it appears in user's code.
5981///
5982/// \param VD Declaration of an identifier that appears in a type tag.
5983///
5984/// \param MagicValue Type tag magic value.
5985bool FindTypeTagExpr(const Expr *TypeExpr, const ASTContext &Ctx,
5986                     const ValueDecl **VD, uint64_t *MagicValue) {
5987  while(true) {
5988    if (!TypeExpr)
5989      return false;
5990
5991    TypeExpr = TypeExpr->IgnoreParenImpCasts()->IgnoreParenCasts();
5992
5993    switch (TypeExpr->getStmtClass()) {
5994    case Stmt::UnaryOperatorClass: {
5995      const UnaryOperator *UO = cast<UnaryOperator>(TypeExpr);
5996      if (UO->getOpcode() == UO_AddrOf || UO->getOpcode() == UO_Deref) {
5997        TypeExpr = UO->getSubExpr();
5998        continue;
5999      }
6000      return false;
6001    }
6002
6003    case Stmt::DeclRefExprClass: {
6004      const DeclRefExpr *DRE = cast<DeclRefExpr>(TypeExpr);
6005      *VD = DRE->getDecl();
6006      return true;
6007    }
6008
6009    case Stmt::IntegerLiteralClass: {
6010      const IntegerLiteral *IL = cast<IntegerLiteral>(TypeExpr);
6011      llvm::APInt MagicValueAPInt = IL->getValue();
6012      if (MagicValueAPInt.getActiveBits() <= 64) {
6013        *MagicValue = MagicValueAPInt.getZExtValue();
6014        return true;
6015      } else
6016        return false;
6017    }
6018
6019    case Stmt::BinaryConditionalOperatorClass:
6020    case Stmt::ConditionalOperatorClass: {
6021      const AbstractConditionalOperator *ACO =
6022          cast<AbstractConditionalOperator>(TypeExpr);
6023      bool Result;
6024      if (ACO->getCond()->EvaluateAsBooleanCondition(Result, Ctx)) {
6025        if (Result)
6026          TypeExpr = ACO->getTrueExpr();
6027        else
6028          TypeExpr = ACO->getFalseExpr();
6029        continue;
6030      }
6031      return false;
6032    }
6033
6034    case Stmt::BinaryOperatorClass: {
6035      const BinaryOperator *BO = cast<BinaryOperator>(TypeExpr);
6036      if (BO->getOpcode() == BO_Comma) {
6037        TypeExpr = BO->getRHS();
6038        continue;
6039      }
6040      return false;
6041    }
6042
6043    default:
6044      return false;
6045    }
6046  }
6047}
6048
6049/// \brief Retrieve the C type corresponding to type tag TypeExpr.
6050///
6051/// \param TypeExpr Expression that specifies a type tag.
6052///
6053/// \param MagicValues Registered magic values.
6054///
6055/// \param FoundWrongKind Set to true if a type tag was found, but of a wrong
6056///        kind.
6057///
6058/// \param TypeInfo Information about the corresponding C type.
6059///
6060/// \returns true if the corresponding C type was found.
6061bool GetMatchingCType(
6062        const IdentifierInfo *ArgumentKind,
6063        const Expr *TypeExpr, const ASTContext &Ctx,
6064        const llvm::DenseMap<Sema::TypeTagMagicValue,
6065                             Sema::TypeTagData> *MagicValues,
6066        bool &FoundWrongKind,
6067        Sema::TypeTagData &TypeInfo) {
6068  FoundWrongKind = false;
6069
6070  // Variable declaration that has type_tag_for_datatype attribute.
6071  const ValueDecl *VD = NULL;
6072
6073  uint64_t MagicValue;
6074
6075  if (!FindTypeTagExpr(TypeExpr, Ctx, &VD, &MagicValue))
6076    return false;
6077
6078  if (VD) {
6079    for (specific_attr_iterator<TypeTagForDatatypeAttr>
6080             I = VD->specific_attr_begin<TypeTagForDatatypeAttr>(),
6081             E = VD->specific_attr_end<TypeTagForDatatypeAttr>();
6082         I != E; ++I) {
6083      if (I->getArgumentKind() != ArgumentKind) {
6084        FoundWrongKind = true;
6085        return false;
6086      }
6087      TypeInfo.Type = I->getMatchingCType();
6088      TypeInfo.LayoutCompatible = I->getLayoutCompatible();
6089      TypeInfo.MustBeNull = I->getMustBeNull();
6090      return true;
6091    }
6092    return false;
6093  }
6094
6095  if (!MagicValues)
6096    return false;
6097
6098  llvm::DenseMap<Sema::TypeTagMagicValue,
6099                 Sema::TypeTagData>::const_iterator I =
6100      MagicValues->find(std::make_pair(ArgumentKind, MagicValue));
6101  if (I == MagicValues->end())
6102    return false;
6103
6104  TypeInfo = I->second;
6105  return true;
6106}
6107} // unnamed namespace
6108
6109void Sema::RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind,
6110                                      uint64_t MagicValue, QualType Type,
6111                                      bool LayoutCompatible,
6112                                      bool MustBeNull) {
6113  if (!TypeTagForDatatypeMagicValues)
6114    TypeTagForDatatypeMagicValues.reset(
6115        new llvm::DenseMap<TypeTagMagicValue, TypeTagData>);
6116
6117  TypeTagMagicValue Magic(ArgumentKind, MagicValue);
6118  (*TypeTagForDatatypeMagicValues)[Magic] =
6119      TypeTagData(Type, LayoutCompatible, MustBeNull);
6120}
6121
6122namespace {
6123bool IsSameCharType(QualType T1, QualType T2) {
6124  const BuiltinType *BT1 = T1->getAs<BuiltinType>();
6125  if (!BT1)
6126    return false;
6127
6128  const BuiltinType *BT2 = T2->getAs<BuiltinType>();
6129  if (!BT2)
6130    return false;
6131
6132  BuiltinType::Kind T1Kind = BT1->getKind();
6133  BuiltinType::Kind T2Kind = BT2->getKind();
6134
6135  return (T1Kind == BuiltinType::SChar  && T2Kind == BuiltinType::Char_S) ||
6136         (T1Kind == BuiltinType::UChar  && T2Kind == BuiltinType::Char_U) ||
6137         (T1Kind == BuiltinType::Char_U && T2Kind == BuiltinType::UChar) ||
6138         (T1Kind == BuiltinType::Char_S && T2Kind == BuiltinType::SChar);
6139}
6140} // unnamed namespace
6141
6142void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr,
6143                                    const Expr * const *ExprArgs) {
6144  const IdentifierInfo *ArgumentKind = Attr->getArgumentKind();
6145  bool IsPointerAttr = Attr->getIsPointer();
6146
6147  const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()];
6148  bool FoundWrongKind;
6149  TypeTagData TypeInfo;
6150  if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context,
6151                        TypeTagForDatatypeMagicValues.get(),
6152                        FoundWrongKind, TypeInfo)) {
6153    if (FoundWrongKind)
6154      Diag(TypeTagExpr->getExprLoc(),
6155           diag::warn_type_tag_for_datatype_wrong_kind)
6156        << TypeTagExpr->getSourceRange();
6157    return;
6158  }
6159
6160  const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()];
6161  if (IsPointerAttr) {
6162    // Skip implicit cast of pointer to `void *' (as a function argument).
6163    if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr))
6164      if (ICE->getType()->isVoidPointerType())
6165        ArgumentExpr = ICE->getSubExpr();
6166  }
6167  QualType ArgumentType = ArgumentExpr->getType();
6168
6169  // Passing a `void*' pointer shouldn't trigger a warning.
6170  if (IsPointerAttr && ArgumentType->isVoidPointerType())
6171    return;
6172
6173  if (TypeInfo.MustBeNull) {
6174    // Type tag with matching void type requires a null pointer.
6175    if (!ArgumentExpr->isNullPointerConstant(Context,
6176                                             Expr::NPC_ValueDependentIsNotNull)) {
6177      Diag(ArgumentExpr->getExprLoc(),
6178           diag::warn_type_safety_null_pointer_required)
6179          << ArgumentKind->getName()
6180          << ArgumentExpr->getSourceRange()
6181          << TypeTagExpr->getSourceRange();
6182    }
6183    return;
6184  }
6185
6186  QualType RequiredType = TypeInfo.Type;
6187  if (IsPointerAttr)
6188    RequiredType = Context.getPointerType(RequiredType);
6189
6190  bool mismatch = false;
6191  if (!TypeInfo.LayoutCompatible) {
6192    mismatch = !Context.hasSameType(ArgumentType, RequiredType);
6193
6194    // C++11 [basic.fundamental] p1:
6195    // Plain char, signed char, and unsigned char are three distinct types.
6196    //
6197    // But we treat plain `char' as equivalent to `signed char' or `unsigned
6198    // char' depending on the current char signedness mode.
6199    if (mismatch)
6200      if ((IsPointerAttr && IsSameCharType(ArgumentType->getPointeeType(),
6201                                           RequiredType->getPointeeType())) ||
6202          (!IsPointerAttr && IsSameCharType(ArgumentType, RequiredType)))
6203        mismatch = false;
6204  } else
6205    if (IsPointerAttr)
6206      mismatch = !isLayoutCompatible(Context,
6207                                     ArgumentType->getPointeeType(),
6208                                     RequiredType->getPointeeType());
6209    else
6210      mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType);
6211
6212  if (mismatch)
6213    Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch)
6214        << ArgumentType << ArgumentKind->getName()
6215        << TypeInfo.LayoutCompatible << RequiredType
6216        << ArgumentExpr->getSourceRange()
6217        << TypeTagExpr->getSourceRange();
6218}
6219