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