SemaChecking.cpp revision 625bb569df0c34feec0d52c0ec5215f21ef2e054 
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/ScopeInfo.h"
20#include "clang/Analysis/Analyses/FormatString.h"
21#include "clang/AST/ASTContext.h"
22#include "clang/AST/CharUnits.h"
23#include "clang/AST/DeclCXX.h"
24#include "clang/AST/DeclObjC.h"
25#include "clang/AST/ExprCXX.h"
26#include "clang/AST/ExprObjC.h"
27#include "clang/AST/EvaluatedExprVisitor.h"
28#include "clang/AST/DeclObjC.h"
29#include "clang/AST/StmtCXX.h"
30#include "clang/AST/StmtObjC.h"
31#include "clang/Lex/Preprocessor.h"
32#include "llvm/ADT/BitVector.h"
33#include "llvm/ADT/SmallString.h"
34#include "llvm/ADT/STLExtras.h"
35#include "llvm/Support/raw_ostream.h"
36#include "clang/Basic/TargetBuiltins.h"
37#include "clang/Basic/TargetInfo.h"
38#include "clang/Basic/ConvertUTF.h"
39#include <limits>
40using namespace clang;
41using namespace sema;
42
43SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL,
44                                                    unsigned ByteNo) const {
45  return SL->getLocationOfByte(ByteNo, PP.getSourceManager(),
46                               PP.getLangOptions(), PP.getTargetInfo());
47}
48
49/// Checks that a call expression's argument count is the desired number.
50/// This is useful when doing custom type-checking.  Returns true on error.
51static bool checkArgCount(Sema &S, CallExpr *call, unsigned desiredArgCount) {
52  unsigned argCount = call->getNumArgs();
53  if (argCount == desiredArgCount) return false;
54
55  if (argCount < desiredArgCount)
56    return S.Diag(call->getLocEnd(), diag::err_typecheck_call_too_few_args)
57        << 0 /*function call*/ << desiredArgCount << argCount
58        << call->getSourceRange();
59
60  // Highlight all the excess arguments.
61  SourceRange range(call->getArg(desiredArgCount)->getLocStart(),
62                    call->getArg(argCount - 1)->getLocEnd());
63
64  return S.Diag(range.getBegin(), diag::err_typecheck_call_too_many_args)
65    << 0 /*function call*/ << desiredArgCount << argCount
66    << call->getArg(1)->getSourceRange();
67}
68
69/// CheckBuiltinAnnotationString - Checks that string argument to the builtin
70/// annotation is a non wide string literal.
71static bool CheckBuiltinAnnotationString(Sema &S, Expr *Arg) {
72  Arg = Arg->IgnoreParenCasts();
73  StringLiteral *Literal = dyn_cast<StringLiteral>(Arg);
74  if (!Literal || !Literal->isAscii()) {
75    S.Diag(Arg->getLocStart(), diag::err_builtin_annotation_not_string_constant)
76      << Arg->getSourceRange();
77    return true;
78  }
79  return false;
80}
81
82ExprResult
83Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
84  ExprResult TheCallResult(Owned(TheCall));
85
86  // Find out if any arguments are required to be integer constant expressions.
87  unsigned ICEArguments = 0;
88  ASTContext::GetBuiltinTypeError Error;
89  Context.GetBuiltinType(BuiltinID, Error, &ICEArguments);
90  if (Error != ASTContext::GE_None)
91    ICEArguments = 0;  // Don't diagnose previously diagnosed errors.
92
93  // If any arguments are required to be ICE's, check and diagnose.
94  for (unsigned ArgNo = 0; ICEArguments != 0; ++ArgNo) {
95    // Skip arguments not required to be ICE's.
96    if ((ICEArguments & (1 << ArgNo)) == 0) continue;
97
98    llvm::APSInt Result;
99    if (SemaBuiltinConstantArg(TheCall, ArgNo, Result))
100      return true;
101    ICEArguments &= ~(1 << ArgNo);
102  }
103
104  switch (BuiltinID) {
105  case Builtin::BI__builtin___CFStringMakeConstantString:
106    assert(TheCall->getNumArgs() == 1 &&
107           "Wrong # arguments to builtin CFStringMakeConstantString");
108    if (CheckObjCString(TheCall->getArg(0)))
109      return ExprError();
110    break;
111  case Builtin::BI__builtin_stdarg_start:
112  case Builtin::BI__builtin_va_start:
113    if (SemaBuiltinVAStart(TheCall))
114      return ExprError();
115    break;
116  case Builtin::BI__builtin_isgreater:
117  case Builtin::BI__builtin_isgreaterequal:
118  case Builtin::BI__builtin_isless:
119  case Builtin::BI__builtin_islessequal:
120  case Builtin::BI__builtin_islessgreater:
121  case Builtin::BI__builtin_isunordered:
122    if (SemaBuiltinUnorderedCompare(TheCall))
123      return ExprError();
124    break;
125  case Builtin::BI__builtin_fpclassify:
126    if (SemaBuiltinFPClassification(TheCall, 6))
127      return ExprError();
128    break;
129  case Builtin::BI__builtin_isfinite:
130  case Builtin::BI__builtin_isinf:
131  case Builtin::BI__builtin_isinf_sign:
132  case Builtin::BI__builtin_isnan:
133  case Builtin::BI__builtin_isnormal:
134    if (SemaBuiltinFPClassification(TheCall, 1))
135      return ExprError();
136    break;
137  case Builtin::BI__builtin_shufflevector:
138    return SemaBuiltinShuffleVector(TheCall);
139    // TheCall will be freed by the smart pointer here, but that's fine, since
140    // SemaBuiltinShuffleVector guts it, but then doesn't release it.
141  case Builtin::BI__builtin_prefetch:
142    if (SemaBuiltinPrefetch(TheCall))
143      return ExprError();
144    break;
145  case Builtin::BI__builtin_object_size:
146    if (SemaBuiltinObjectSize(TheCall))
147      return ExprError();
148    break;
149  case Builtin::BI__builtin_longjmp:
150    if (SemaBuiltinLongjmp(TheCall))
151      return ExprError();
152    break;
153
154  case Builtin::BI__builtin_classify_type:
155    if (checkArgCount(*this, TheCall, 1)) return true;
156    TheCall->setType(Context.IntTy);
157    break;
158  case Builtin::BI__builtin_constant_p:
159    if (checkArgCount(*this, TheCall, 1)) return true;
160    TheCall->setType(Context.IntTy);
161    break;
162  case Builtin::BI__sync_fetch_and_add:
163  case Builtin::BI__sync_fetch_and_add_1:
164  case Builtin::BI__sync_fetch_and_add_2:
165  case Builtin::BI__sync_fetch_and_add_4:
166  case Builtin::BI__sync_fetch_and_add_8:
167  case Builtin::BI__sync_fetch_and_add_16:
168  case Builtin::BI__sync_fetch_and_sub:
169  case Builtin::BI__sync_fetch_and_sub_1:
170  case Builtin::BI__sync_fetch_and_sub_2:
171  case Builtin::BI__sync_fetch_and_sub_4:
172  case Builtin::BI__sync_fetch_and_sub_8:
173  case Builtin::BI__sync_fetch_and_sub_16:
174  case Builtin::BI__sync_fetch_and_or:
175  case Builtin::BI__sync_fetch_and_or_1:
176  case Builtin::BI__sync_fetch_and_or_2:
177  case Builtin::BI__sync_fetch_and_or_4:
178  case Builtin::BI__sync_fetch_and_or_8:
179  case Builtin::BI__sync_fetch_and_or_16:
180  case Builtin::BI__sync_fetch_and_and:
181  case Builtin::BI__sync_fetch_and_and_1:
182  case Builtin::BI__sync_fetch_and_and_2:
183  case Builtin::BI__sync_fetch_and_and_4:
184  case Builtin::BI__sync_fetch_and_and_8:
185  case Builtin::BI__sync_fetch_and_and_16:
186  case Builtin::BI__sync_fetch_and_xor:
187  case Builtin::BI__sync_fetch_and_xor_1:
188  case Builtin::BI__sync_fetch_and_xor_2:
189  case Builtin::BI__sync_fetch_and_xor_4:
190  case Builtin::BI__sync_fetch_and_xor_8:
191  case Builtin::BI__sync_fetch_and_xor_16:
192  case Builtin::BI__sync_add_and_fetch:
193  case Builtin::BI__sync_add_and_fetch_1:
194  case Builtin::BI__sync_add_and_fetch_2:
195  case Builtin::BI__sync_add_and_fetch_4:
196  case Builtin::BI__sync_add_and_fetch_8:
197  case Builtin::BI__sync_add_and_fetch_16:
198  case Builtin::BI__sync_sub_and_fetch:
199  case Builtin::BI__sync_sub_and_fetch_1:
200  case Builtin::BI__sync_sub_and_fetch_2:
201  case Builtin::BI__sync_sub_and_fetch_4:
202  case Builtin::BI__sync_sub_and_fetch_8:
203  case Builtin::BI__sync_sub_and_fetch_16:
204  case Builtin::BI__sync_and_and_fetch:
205  case Builtin::BI__sync_and_and_fetch_1:
206  case Builtin::BI__sync_and_and_fetch_2:
207  case Builtin::BI__sync_and_and_fetch_4:
208  case Builtin::BI__sync_and_and_fetch_8:
209  case Builtin::BI__sync_and_and_fetch_16:
210  case Builtin::BI__sync_or_and_fetch:
211  case Builtin::BI__sync_or_and_fetch_1:
212  case Builtin::BI__sync_or_and_fetch_2:
213  case Builtin::BI__sync_or_and_fetch_4:
214  case Builtin::BI__sync_or_and_fetch_8:
215  case Builtin::BI__sync_or_and_fetch_16:
216  case Builtin::BI__sync_xor_and_fetch:
217  case Builtin::BI__sync_xor_and_fetch_1:
218  case Builtin::BI__sync_xor_and_fetch_2:
219  case Builtin::BI__sync_xor_and_fetch_4:
220  case Builtin::BI__sync_xor_and_fetch_8:
221  case Builtin::BI__sync_xor_and_fetch_16:
222  case Builtin::BI__sync_val_compare_and_swap:
223  case Builtin::BI__sync_val_compare_and_swap_1:
224  case Builtin::BI__sync_val_compare_and_swap_2:
225  case Builtin::BI__sync_val_compare_and_swap_4:
226  case Builtin::BI__sync_val_compare_and_swap_8:
227  case Builtin::BI__sync_val_compare_and_swap_16:
228  case Builtin::BI__sync_bool_compare_and_swap:
229  case Builtin::BI__sync_bool_compare_and_swap_1:
230  case Builtin::BI__sync_bool_compare_and_swap_2:
231  case Builtin::BI__sync_bool_compare_and_swap_4:
232  case Builtin::BI__sync_bool_compare_and_swap_8:
233  case Builtin::BI__sync_bool_compare_and_swap_16:
234  case Builtin::BI__sync_lock_test_and_set:
235  case Builtin::BI__sync_lock_test_and_set_1:
236  case Builtin::BI__sync_lock_test_and_set_2:
237  case Builtin::BI__sync_lock_test_and_set_4:
238  case Builtin::BI__sync_lock_test_and_set_8:
239  case Builtin::BI__sync_lock_test_and_set_16:
240  case Builtin::BI__sync_lock_release:
241  case Builtin::BI__sync_lock_release_1:
242  case Builtin::BI__sync_lock_release_2:
243  case Builtin::BI__sync_lock_release_4:
244  case Builtin::BI__sync_lock_release_8:
245  case Builtin::BI__sync_lock_release_16:
246  case Builtin::BI__sync_swap:
247  case Builtin::BI__sync_swap_1:
248  case Builtin::BI__sync_swap_2:
249  case Builtin::BI__sync_swap_4:
250  case Builtin::BI__sync_swap_8:
251  case Builtin::BI__sync_swap_16:
252    return SemaBuiltinAtomicOverloaded(move(TheCallResult));
253  case Builtin::BI__atomic_load:
254    return SemaAtomicOpsOverloaded(move(TheCallResult), AtomicExpr::Load);
255  case Builtin::BI__atomic_store:
256    return SemaAtomicOpsOverloaded(move(TheCallResult), AtomicExpr::Store);
257  case Builtin::BI__atomic_init:
258    return SemaAtomicOpsOverloaded(move(TheCallResult), AtomicExpr::Init);
259  case Builtin::BI__atomic_exchange:
260    return SemaAtomicOpsOverloaded(move(TheCallResult), AtomicExpr::Xchg);
261  case Builtin::BI__atomic_compare_exchange_strong:
262    return SemaAtomicOpsOverloaded(move(TheCallResult),
263                                   AtomicExpr::CmpXchgStrong);
264  case Builtin::BI__atomic_compare_exchange_weak:
265    return SemaAtomicOpsOverloaded(move(TheCallResult),
266                                   AtomicExpr::CmpXchgWeak);
267  case Builtin::BI__atomic_fetch_add:
268    return SemaAtomicOpsOverloaded(move(TheCallResult), AtomicExpr::Add);
269  case Builtin::BI__atomic_fetch_sub:
270    return SemaAtomicOpsOverloaded(move(TheCallResult), AtomicExpr::Sub);
271  case Builtin::BI__atomic_fetch_and:
272    return SemaAtomicOpsOverloaded(move(TheCallResult), AtomicExpr::And);
273  case Builtin::BI__atomic_fetch_or:
274    return SemaAtomicOpsOverloaded(move(TheCallResult), AtomicExpr::Or);
275  case Builtin::BI__atomic_fetch_xor:
276    return SemaAtomicOpsOverloaded(move(TheCallResult), AtomicExpr::Xor);
277  case Builtin::BI__builtin_annotation:
278    if (CheckBuiltinAnnotationString(*this, TheCall->getArg(1)))
279      return ExprError();
280    break;
281  }
282
283  // Since the target specific builtins for each arch overlap, only check those
284  // of the arch we are compiling for.
285  if (BuiltinID >= Builtin::FirstTSBuiltin) {
286    switch (Context.getTargetInfo().getTriple().getArch()) {
287      case llvm::Triple::arm:
288      case llvm::Triple::thumb:
289        if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall))
290          return ExprError();
291        break;
292      default:
293        break;
294    }
295  }
296
297  return move(TheCallResult);
298}
299
300// Get the valid immediate range for the specified NEON type code.
301static unsigned RFT(unsigned t, bool shift = false) {
302  NeonTypeFlags Type(t);
303  int IsQuad = Type.isQuad();
304  switch (Type.getEltType()) {
305  case NeonTypeFlags::Int8:
306  case NeonTypeFlags::Poly8:
307    return shift ? 7 : (8 << IsQuad) - 1;
308  case NeonTypeFlags::Int16:
309  case NeonTypeFlags::Poly16:
310    return shift ? 15 : (4 << IsQuad) - 1;
311  case NeonTypeFlags::Int32:
312    return shift ? 31 : (2 << IsQuad) - 1;
313  case NeonTypeFlags::Int64:
314    return shift ? 63 : (1 << IsQuad) - 1;
315  case NeonTypeFlags::Float16:
316    assert(!shift && "cannot shift float types!");
317    return (4 << IsQuad) - 1;
318  case NeonTypeFlags::Float32:
319    assert(!shift && "cannot shift float types!");
320    return (2 << IsQuad) - 1;
321  }
322  llvm_unreachable("Invalid NeonTypeFlag!");
323}
324
325/// getNeonEltType - Return the QualType corresponding to the elements of
326/// the vector type specified by the NeonTypeFlags.  This is used to check
327/// the pointer arguments for Neon load/store intrinsics.
328static QualType getNeonEltType(NeonTypeFlags Flags, ASTContext &Context) {
329  switch (Flags.getEltType()) {
330  case NeonTypeFlags::Int8:
331    return Flags.isUnsigned() ? Context.UnsignedCharTy : Context.SignedCharTy;
332  case NeonTypeFlags::Int16:
333    return Flags.isUnsigned() ? Context.UnsignedShortTy : Context.ShortTy;
334  case NeonTypeFlags::Int32:
335    return Flags.isUnsigned() ? Context.UnsignedIntTy : Context.IntTy;
336  case NeonTypeFlags::Int64:
337    return Flags.isUnsigned() ? Context.UnsignedLongLongTy : Context.LongLongTy;
338  case NeonTypeFlags::Poly8:
339    return Context.SignedCharTy;
340  case NeonTypeFlags::Poly16:
341    return Context.ShortTy;
342  case NeonTypeFlags::Float16:
343    return Context.UnsignedShortTy;
344  case NeonTypeFlags::Float32:
345    return Context.FloatTy;
346  }
347  llvm_unreachable("Invalid NeonTypeFlag!");
348}
349
350bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
351  llvm::APSInt Result;
352
353  unsigned mask = 0;
354  unsigned TV = 0;
355  int PtrArgNum = -1;
356  bool HasConstPtr = false;
357  switch (BuiltinID) {
358#define GET_NEON_OVERLOAD_CHECK
359#include "clang/Basic/arm_neon.inc"
360#undef GET_NEON_OVERLOAD_CHECK
361  }
362
363  // For NEON intrinsics which are overloaded on vector element type, validate
364  // the immediate which specifies which variant to emit.
365  unsigned ImmArg = TheCall->getNumArgs()-1;
366  if (mask) {
367    if (SemaBuiltinConstantArg(TheCall, ImmArg, Result))
368      return true;
369
370    TV = Result.getLimitedValue(64);
371    if ((TV > 63) || (mask & (1 << TV)) == 0)
372      return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code)
373        << TheCall->getArg(ImmArg)->getSourceRange();
374  }
375
376  if (PtrArgNum >= 0) {
377    // Check that pointer arguments have the specified type.
378    Expr *Arg = TheCall->getArg(PtrArgNum);
379    if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg))
380      Arg = ICE->getSubExpr();
381    ExprResult RHS = DefaultFunctionArrayLvalueConversion(Arg);
382    QualType RHSTy = RHS.get()->getType();
383    QualType EltTy = getNeonEltType(NeonTypeFlags(TV), Context);
384    if (HasConstPtr)
385      EltTy = EltTy.withConst();
386    QualType LHSTy = Context.getPointerType(EltTy);
387    AssignConvertType ConvTy;
388    ConvTy = CheckSingleAssignmentConstraints(LHSTy, RHS);
389    if (RHS.isInvalid())
390      return true;
391    if (DiagnoseAssignmentResult(ConvTy, Arg->getLocStart(), LHSTy, RHSTy,
392                                 RHS.get(), AA_Assigning))
393      return true;
394  }
395
396  // For NEON intrinsics which take an immediate value as part of the
397  // instruction, range check them here.
398  unsigned i = 0, l = 0, u = 0;
399  switch (BuiltinID) {
400  default: return false;
401  case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break;
402  case ARM::BI__builtin_arm_usat: i = 1; u = 31; break;
403  case ARM::BI__builtin_arm_vcvtr_f:
404  case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break;
405#define GET_NEON_IMMEDIATE_CHECK
406#include "clang/Basic/arm_neon.inc"
407#undef GET_NEON_IMMEDIATE_CHECK
408  };
409
410  // Check that the immediate argument is actually a constant.
411  if (SemaBuiltinConstantArg(TheCall, i, Result))
412    return true;
413
414  // Range check against the upper/lower values for this isntruction.
415  unsigned Val = Result.getZExtValue();
416  if (Val < l || Val > (u + l))
417    return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
418      << l << u+l << TheCall->getArg(i)->getSourceRange();
419
420  // FIXME: VFP Intrinsics should error if VFP not present.
421  return false;
422}
423
424/// CheckFunctionCall - Check a direct function call for various correctness
425/// and safety properties not strictly enforced by the C type system.
426bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall) {
427  // Get the IdentifierInfo* for the called function.
428  IdentifierInfo *FnInfo = FDecl->getIdentifier();
429
430  // None of the checks below are needed for functions that don't have
431  // simple names (e.g., C++ conversion functions).
432  if (!FnInfo)
433    return false;
434
435  // FIXME: This mechanism should be abstracted to be less fragile and
436  // more efficient. For example, just map function ids to custom
437  // handlers.
438
439  // Printf and scanf checking.
440  for (specific_attr_iterator<FormatAttr>
441         i = FDecl->specific_attr_begin<FormatAttr>(),
442         e = FDecl->specific_attr_end<FormatAttr>(); i != e ; ++i) {
443    CheckFormatArguments(*i, TheCall);
444  }
445
446  for (specific_attr_iterator<NonNullAttr>
447         i = FDecl->specific_attr_begin<NonNullAttr>(),
448         e = FDecl->specific_attr_end<NonNullAttr>(); i != e; ++i) {
449    CheckNonNullArguments(*i, TheCall->getArgs(),
450                          TheCall->getCallee()->getLocStart());
451  }
452
453  unsigned CMId = FDecl->getMemoryFunctionKind();
454  if (CMId == 0)
455    return false;
456
457  // Handle memory setting and copying functions.
458  if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat)
459    CheckStrlcpycatArguments(TheCall, FnInfo);
460  else if (CMId == Builtin::BIstrncat)
461    CheckStrncatArguments(TheCall, FnInfo);
462  else
463    CheckMemaccessArguments(TheCall, CMId, FnInfo);
464
465  return false;
466}
467
468bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac,
469                               Expr **Args, unsigned NumArgs) {
470  for (specific_attr_iterator<FormatAttr>
471       i = Method->specific_attr_begin<FormatAttr>(),
472       e = Method->specific_attr_end<FormatAttr>(); i != e ; ++i) {
473
474    CheckFormatArguments(*i, Args, NumArgs, false, lbrac,
475                         Method->getSourceRange());
476  }
477
478  // diagnose nonnull arguments.
479  for (specific_attr_iterator<NonNullAttr>
480       i = Method->specific_attr_begin<NonNullAttr>(),
481       e = Method->specific_attr_end<NonNullAttr>(); i != e; ++i) {
482    CheckNonNullArguments(*i, Args, lbrac);
483  }
484
485  return false;
486}
487
488bool Sema::CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall) {
489  const VarDecl *V = dyn_cast<VarDecl>(NDecl);
490  if (!V)
491    return false;
492
493  QualType Ty = V->getType();
494  if (!Ty->isBlockPointerType())
495    return false;
496
497  // format string checking.
498  for (specific_attr_iterator<FormatAttr>
499       i = NDecl->specific_attr_begin<FormatAttr>(),
500       e = NDecl->specific_attr_end<FormatAttr>(); i != e ; ++i) {
501    CheckFormatArguments(*i, TheCall);
502  }
503
504  return false;
505}
506
507ExprResult
508Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult, AtomicExpr::AtomicOp Op) {
509  CallExpr *TheCall = cast<CallExpr>(TheCallResult.get());
510  DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
511
512  // All these operations take one of the following four forms:
513  // T   __atomic_load(_Atomic(T)*, int)                              (loads)
514  // T*  __atomic_add(_Atomic(T*)*, ptrdiff_t, int)         (pointer add/sub)
515  // int __atomic_compare_exchange_strong(_Atomic(T)*, T*, T, int, int)
516  //                                                                (cmpxchg)
517  // T   __atomic_exchange(_Atomic(T)*, T, int)             (everything else)
518  // where T is an appropriate type, and the int paremeterss are for orderings.
519  unsigned NumVals = 1;
520  unsigned NumOrders = 1;
521  if (Op == AtomicExpr::Load) {
522    NumVals = 0;
523  } else if (Op == AtomicExpr::CmpXchgWeak || Op == AtomicExpr::CmpXchgStrong) {
524    NumVals = 2;
525    NumOrders = 2;
526  }
527  if (Op == AtomicExpr::Init)
528    NumOrders = 0;
529
530  if (TheCall->getNumArgs() < NumVals+NumOrders+1) {
531    Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
532      << 0 << NumVals+NumOrders+1 << TheCall->getNumArgs()
533      << TheCall->getCallee()->getSourceRange();
534    return ExprError();
535  } else if (TheCall->getNumArgs() > NumVals+NumOrders+1) {
536    Diag(TheCall->getArg(NumVals+NumOrders+1)->getLocStart(),
537         diag::err_typecheck_call_too_many_args)
538      << 0 << NumVals+NumOrders+1 << TheCall->getNumArgs()
539      << TheCall->getCallee()->getSourceRange();
540    return ExprError();
541  }
542
543  // Inspect the first argument of the atomic operation.  This should always be
544  // a pointer to an _Atomic type.
545  Expr *Ptr = TheCall->getArg(0);
546  Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get();
547  const PointerType *pointerType = Ptr->getType()->getAs<PointerType>();
548  if (!pointerType) {
549    Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic)
550      << Ptr->getType() << Ptr->getSourceRange();
551    return ExprError();
552  }
553
554  QualType AtomTy = pointerType->getPointeeType();
555  if (!AtomTy->isAtomicType()) {
556    Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic)
557      << Ptr->getType() << Ptr->getSourceRange();
558    return ExprError();
559  }
560  QualType ValType = AtomTy->getAs<AtomicType>()->getValueType();
561
562  if ((Op == AtomicExpr::Add || Op == AtomicExpr::Sub) &&
563      !ValType->isIntegerType() && !ValType->isPointerType()) {
564    Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr)
565      << Ptr->getType() << Ptr->getSourceRange();
566    return ExprError();
567  }
568
569  if (!ValType->isIntegerType() &&
570      (Op == AtomicExpr::And || Op == AtomicExpr::Or || Op == AtomicExpr::Xor)){
571    Diag(DRE->getLocStart(), diag::err_atomic_op_logical_needs_atomic_int)
572      << Ptr->getType() << Ptr->getSourceRange();
573    return ExprError();
574  }
575
576  switch (ValType.getObjCLifetime()) {
577  case Qualifiers::OCL_None:
578  case Qualifiers::OCL_ExplicitNone:
579    // okay
580    break;
581
582  case Qualifiers::OCL_Weak:
583  case Qualifiers::OCL_Strong:
584  case Qualifiers::OCL_Autoreleasing:
585    Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
586      << ValType << Ptr->getSourceRange();
587    return ExprError();
588  }
589
590  QualType ResultType = ValType;
591  if (Op == AtomicExpr::Store || Op == AtomicExpr::Init)
592    ResultType = Context.VoidTy;
593  else if (Op == AtomicExpr::CmpXchgWeak || Op == AtomicExpr::CmpXchgStrong)
594    ResultType = Context.BoolTy;
595
596  // The first argument --- the pointer --- has a fixed type; we
597  // deduce the types of the rest of the arguments accordingly.  Walk
598  // the remaining arguments, converting them to the deduced value type.
599  for (unsigned i = 1; i != NumVals+NumOrders+1; ++i) {
600    ExprResult Arg = TheCall->getArg(i);
601    QualType Ty;
602    if (i < NumVals+1) {
603      // The second argument to a cmpxchg is a pointer to the data which will
604      // be exchanged. The second argument to a pointer add/subtract is the
605      // amount to add/subtract, which must be a ptrdiff_t.  The third
606      // argument to a cmpxchg and the second argument in all other cases
607      // is the type of the value.
608      if (i == 1 && (Op == AtomicExpr::CmpXchgWeak ||
609                     Op == AtomicExpr::CmpXchgStrong))
610         Ty = Context.getPointerType(ValType.getUnqualifiedType());
611      else if (!ValType->isIntegerType() &&
612               (Op == AtomicExpr::Add || Op == AtomicExpr::Sub))
613        Ty = Context.getPointerDiffType();
614      else
615        Ty = ValType;
616    } else {
617      // The order(s) are always converted to int.
618      Ty = Context.IntTy;
619    }
620    InitializedEntity Entity =
621        InitializedEntity::InitializeParameter(Context, Ty, false);
622    Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
623    if (Arg.isInvalid())
624      return true;
625    TheCall->setArg(i, Arg.get());
626  }
627
628  SmallVector<Expr*, 5> SubExprs;
629  SubExprs.push_back(Ptr);
630  if (Op == AtomicExpr::Load) {
631    SubExprs.push_back(TheCall->getArg(1)); // Order
632  } else if (Op == AtomicExpr::Init) {
633    SubExprs.push_back(TheCall->getArg(1)); // Val1
634  } else if (Op != AtomicExpr::CmpXchgWeak && Op != AtomicExpr::CmpXchgStrong) {
635    SubExprs.push_back(TheCall->getArg(2)); // Order
636    SubExprs.push_back(TheCall->getArg(1)); // Val1
637  } else {
638    SubExprs.push_back(TheCall->getArg(3)); // Order
639    SubExprs.push_back(TheCall->getArg(1)); // Val1
640    SubExprs.push_back(TheCall->getArg(2)); // Val2
641    SubExprs.push_back(TheCall->getArg(4)); // OrderFail
642  }
643
644  return Owned(new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(),
645                                        SubExprs.data(), SubExprs.size(),
646                                        ResultType, Op,
647                                        TheCall->getRParenLoc()));
648}
649
650
651/// checkBuiltinArgument - Given a call to a builtin function, perform
652/// normal type-checking on the given argument, updating the call in
653/// place.  This is useful when a builtin function requires custom
654/// type-checking for some of its arguments but not necessarily all of
655/// them.
656///
657/// Returns true on error.
658static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) {
659  FunctionDecl *Fn = E->getDirectCallee();
660  assert(Fn && "builtin call without direct callee!");
661
662  ParmVarDecl *Param = Fn->getParamDecl(ArgIndex);
663  InitializedEntity Entity =
664    InitializedEntity::InitializeParameter(S.Context, Param);
665
666  ExprResult Arg = E->getArg(0);
667  Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg);
668  if (Arg.isInvalid())
669    return true;
670
671  E->setArg(ArgIndex, Arg.take());
672  return false;
673}
674
675/// SemaBuiltinAtomicOverloaded - We have a call to a function like
676/// __sync_fetch_and_add, which is an overloaded function based on the pointer
677/// type of its first argument.  The main ActOnCallExpr routines have already
678/// promoted the types of arguments because all of these calls are prototyped as
679/// void(...).
680///
681/// This function goes through and does final semantic checking for these
682/// builtins,
683ExprResult
684Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) {
685  CallExpr *TheCall = (CallExpr *)TheCallResult.get();
686  DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
687  FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
688
689  // Ensure that we have at least one argument to do type inference from.
690  if (TheCall->getNumArgs() < 1) {
691    Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
692      << 0 << 1 << TheCall->getNumArgs()
693      << TheCall->getCallee()->getSourceRange();
694    return ExprError();
695  }
696
697  // Inspect the first argument of the atomic builtin.  This should always be
698  // a pointer type, whose element is an integral scalar or pointer type.
699  // Because it is a pointer type, we don't have to worry about any implicit
700  // casts here.
701  // FIXME: We don't allow floating point scalars as input.
702  Expr *FirstArg = TheCall->getArg(0);
703  ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg);
704  if (FirstArgResult.isInvalid())
705    return ExprError();
706  FirstArg = FirstArgResult.take();
707  TheCall->setArg(0, FirstArg);
708
709  const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>();
710  if (!pointerType) {
711    Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
712      << FirstArg->getType() << FirstArg->getSourceRange();
713    return ExprError();
714  }
715
716  QualType ValType = pointerType->getPointeeType();
717  if (!ValType->isIntegerType() && !ValType->isAnyPointerType() &&
718      !ValType->isBlockPointerType()) {
719    Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr)
720      << FirstArg->getType() << FirstArg->getSourceRange();
721    return ExprError();
722  }
723
724  switch (ValType.getObjCLifetime()) {
725  case Qualifiers::OCL_None:
726  case Qualifiers::OCL_ExplicitNone:
727    // okay
728    break;
729
730  case Qualifiers::OCL_Weak:
731  case Qualifiers::OCL_Strong:
732  case Qualifiers::OCL_Autoreleasing:
733    Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
734      << ValType << FirstArg->getSourceRange();
735    return ExprError();
736  }
737
738  // Strip any qualifiers off ValType.
739  ValType = ValType.getUnqualifiedType();
740
741  // The majority of builtins return a value, but a few have special return
742  // types, so allow them to override appropriately below.
743  QualType ResultType = ValType;
744
745  // We need to figure out which concrete builtin this maps onto.  For example,
746  // __sync_fetch_and_add with a 2 byte object turns into
747  // __sync_fetch_and_add_2.
748#define BUILTIN_ROW(x) \
749  { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \
750    Builtin::BI##x##_8, Builtin::BI##x##_16 }
751
752  static const unsigned BuiltinIndices[][5] = {
753    BUILTIN_ROW(__sync_fetch_and_add),
754    BUILTIN_ROW(__sync_fetch_and_sub),
755    BUILTIN_ROW(__sync_fetch_and_or),
756    BUILTIN_ROW(__sync_fetch_and_and),
757    BUILTIN_ROW(__sync_fetch_and_xor),
758
759    BUILTIN_ROW(__sync_add_and_fetch),
760    BUILTIN_ROW(__sync_sub_and_fetch),
761    BUILTIN_ROW(__sync_and_and_fetch),
762    BUILTIN_ROW(__sync_or_and_fetch),
763    BUILTIN_ROW(__sync_xor_and_fetch),
764
765    BUILTIN_ROW(__sync_val_compare_and_swap),
766    BUILTIN_ROW(__sync_bool_compare_and_swap),
767    BUILTIN_ROW(__sync_lock_test_and_set),
768    BUILTIN_ROW(__sync_lock_release),
769    BUILTIN_ROW(__sync_swap)
770  };
771#undef BUILTIN_ROW
772
773  // Determine the index of the size.
774  unsigned SizeIndex;
775  switch (Context.getTypeSizeInChars(ValType).getQuantity()) {
776  case 1: SizeIndex = 0; break;
777  case 2: SizeIndex = 1; break;
778  case 4: SizeIndex = 2; break;
779  case 8: SizeIndex = 3; break;
780  case 16: SizeIndex = 4; break;
781  default:
782    Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size)
783      << FirstArg->getType() << FirstArg->getSourceRange();
784    return ExprError();
785  }
786
787  // Each of these builtins has one pointer argument, followed by some number of
788  // values (0, 1 or 2) followed by a potentially empty varags list of stuff
789  // that we ignore.  Find out which row of BuiltinIndices to read from as well
790  // as the number of fixed args.
791  unsigned BuiltinID = FDecl->getBuiltinID();
792  unsigned BuiltinIndex, NumFixed = 1;
793  switch (BuiltinID) {
794  default: llvm_unreachable("Unknown overloaded atomic builtin!");
795  case Builtin::BI__sync_fetch_and_add:
796  case Builtin::BI__sync_fetch_and_add_1:
797  case Builtin::BI__sync_fetch_and_add_2:
798  case Builtin::BI__sync_fetch_and_add_4:
799  case Builtin::BI__sync_fetch_and_add_8:
800  case Builtin::BI__sync_fetch_and_add_16:
801    BuiltinIndex = 0;
802    break;
803
804  case Builtin::BI__sync_fetch_and_sub:
805  case Builtin::BI__sync_fetch_and_sub_1:
806  case Builtin::BI__sync_fetch_and_sub_2:
807  case Builtin::BI__sync_fetch_and_sub_4:
808  case Builtin::BI__sync_fetch_and_sub_8:
809  case Builtin::BI__sync_fetch_and_sub_16:
810    BuiltinIndex = 1;
811    break;
812
813  case Builtin::BI__sync_fetch_and_or:
814  case Builtin::BI__sync_fetch_and_or_1:
815  case Builtin::BI__sync_fetch_and_or_2:
816  case Builtin::BI__sync_fetch_and_or_4:
817  case Builtin::BI__sync_fetch_and_or_8:
818  case Builtin::BI__sync_fetch_and_or_16:
819    BuiltinIndex = 2;
820    break;
821
822  case Builtin::BI__sync_fetch_and_and:
823  case Builtin::BI__sync_fetch_and_and_1:
824  case Builtin::BI__sync_fetch_and_and_2:
825  case Builtin::BI__sync_fetch_and_and_4:
826  case Builtin::BI__sync_fetch_and_and_8:
827  case Builtin::BI__sync_fetch_and_and_16:
828    BuiltinIndex = 3;
829    break;
830
831  case Builtin::BI__sync_fetch_and_xor:
832  case Builtin::BI__sync_fetch_and_xor_1:
833  case Builtin::BI__sync_fetch_and_xor_2:
834  case Builtin::BI__sync_fetch_and_xor_4:
835  case Builtin::BI__sync_fetch_and_xor_8:
836  case Builtin::BI__sync_fetch_and_xor_16:
837    BuiltinIndex = 4;
838    break;
839
840  case Builtin::BI__sync_add_and_fetch:
841  case Builtin::BI__sync_add_and_fetch_1:
842  case Builtin::BI__sync_add_and_fetch_2:
843  case Builtin::BI__sync_add_and_fetch_4:
844  case Builtin::BI__sync_add_and_fetch_8:
845  case Builtin::BI__sync_add_and_fetch_16:
846    BuiltinIndex = 5;
847    break;
848
849  case Builtin::BI__sync_sub_and_fetch:
850  case Builtin::BI__sync_sub_and_fetch_1:
851  case Builtin::BI__sync_sub_and_fetch_2:
852  case Builtin::BI__sync_sub_and_fetch_4:
853  case Builtin::BI__sync_sub_and_fetch_8:
854  case Builtin::BI__sync_sub_and_fetch_16:
855    BuiltinIndex = 6;
856    break;
857
858  case Builtin::BI__sync_and_and_fetch:
859  case Builtin::BI__sync_and_and_fetch_1:
860  case Builtin::BI__sync_and_and_fetch_2:
861  case Builtin::BI__sync_and_and_fetch_4:
862  case Builtin::BI__sync_and_and_fetch_8:
863  case Builtin::BI__sync_and_and_fetch_16:
864    BuiltinIndex = 7;
865    break;
866
867  case Builtin::BI__sync_or_and_fetch:
868  case Builtin::BI__sync_or_and_fetch_1:
869  case Builtin::BI__sync_or_and_fetch_2:
870  case Builtin::BI__sync_or_and_fetch_4:
871  case Builtin::BI__sync_or_and_fetch_8:
872  case Builtin::BI__sync_or_and_fetch_16:
873    BuiltinIndex = 8;
874    break;
875
876  case Builtin::BI__sync_xor_and_fetch:
877  case Builtin::BI__sync_xor_and_fetch_1:
878  case Builtin::BI__sync_xor_and_fetch_2:
879  case Builtin::BI__sync_xor_and_fetch_4:
880  case Builtin::BI__sync_xor_and_fetch_8:
881  case Builtin::BI__sync_xor_and_fetch_16:
882    BuiltinIndex = 9;
883    break;
884
885  case Builtin::BI__sync_val_compare_and_swap:
886  case Builtin::BI__sync_val_compare_and_swap_1:
887  case Builtin::BI__sync_val_compare_and_swap_2:
888  case Builtin::BI__sync_val_compare_and_swap_4:
889  case Builtin::BI__sync_val_compare_and_swap_8:
890  case Builtin::BI__sync_val_compare_and_swap_16:
891    BuiltinIndex = 10;
892    NumFixed = 2;
893    break;
894
895  case Builtin::BI__sync_bool_compare_and_swap:
896  case Builtin::BI__sync_bool_compare_and_swap_1:
897  case Builtin::BI__sync_bool_compare_and_swap_2:
898  case Builtin::BI__sync_bool_compare_and_swap_4:
899  case Builtin::BI__sync_bool_compare_and_swap_8:
900  case Builtin::BI__sync_bool_compare_and_swap_16:
901    BuiltinIndex = 11;
902    NumFixed = 2;
903    ResultType = Context.BoolTy;
904    break;
905
906  case Builtin::BI__sync_lock_test_and_set:
907  case Builtin::BI__sync_lock_test_and_set_1:
908  case Builtin::BI__sync_lock_test_and_set_2:
909  case Builtin::BI__sync_lock_test_and_set_4:
910  case Builtin::BI__sync_lock_test_and_set_8:
911  case Builtin::BI__sync_lock_test_and_set_16:
912    BuiltinIndex = 12;
913    break;
914
915  case Builtin::BI__sync_lock_release:
916  case Builtin::BI__sync_lock_release_1:
917  case Builtin::BI__sync_lock_release_2:
918  case Builtin::BI__sync_lock_release_4:
919  case Builtin::BI__sync_lock_release_8:
920  case Builtin::BI__sync_lock_release_16:
921    BuiltinIndex = 13;
922    NumFixed = 0;
923    ResultType = Context.VoidTy;
924    break;
925
926  case Builtin::BI__sync_swap:
927  case Builtin::BI__sync_swap_1:
928  case Builtin::BI__sync_swap_2:
929  case Builtin::BI__sync_swap_4:
930  case Builtin::BI__sync_swap_8:
931  case Builtin::BI__sync_swap_16:
932    BuiltinIndex = 14;
933    break;
934  }
935
936  // Now that we know how many fixed arguments we expect, first check that we
937  // have at least that many.
938  if (TheCall->getNumArgs() < 1+NumFixed) {
939    Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
940      << 0 << 1+NumFixed << TheCall->getNumArgs()
941      << TheCall->getCallee()->getSourceRange();
942    return ExprError();
943  }
944
945  // Get the decl for the concrete builtin from this, we can tell what the
946  // concrete integer type we should convert to is.
947  unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex];
948  const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID);
949  IdentifierInfo *NewBuiltinII = PP.getIdentifierInfo(NewBuiltinName);
950  FunctionDecl *NewBuiltinDecl =
951    cast<FunctionDecl>(LazilyCreateBuiltin(NewBuiltinII, NewBuiltinID,
952                                           TUScope, false, DRE->getLocStart()));
953
954  // The first argument --- the pointer --- has a fixed type; we
955  // deduce the types of the rest of the arguments accordingly.  Walk
956  // the remaining arguments, converting them to the deduced value type.
957  for (unsigned i = 0; i != NumFixed; ++i) {
958    ExprResult Arg = TheCall->getArg(i+1);
959
960    // GCC does an implicit conversion to the pointer or integer ValType.  This
961    // can fail in some cases (1i -> int**), check for this error case now.
962    // Initialize the argument.
963    InitializedEntity Entity = InitializedEntity::InitializeParameter(Context,
964                                                   ValType, /*consume*/ false);
965    Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
966    if (Arg.isInvalid())
967      return ExprError();
968
969    // Okay, we have something that *can* be converted to the right type.  Check
970    // to see if there is a potentially weird extension going on here.  This can
971    // happen when you do an atomic operation on something like an char* and
972    // pass in 42.  The 42 gets converted to char.  This is even more strange
973    // for things like 45.123 -> char, etc.
974    // FIXME: Do this check.
975    TheCall->setArg(i+1, Arg.take());
976  }
977
978  ASTContext& Context = this->getASTContext();
979
980  // Create a new DeclRefExpr to refer to the new decl.
981  DeclRefExpr* NewDRE = DeclRefExpr::Create(
982      Context,
983      DRE->getQualifierLoc(),
984      SourceLocation(),
985      NewBuiltinDecl,
986      DRE->getLocation(),
987      NewBuiltinDecl->getType(),
988      DRE->getValueKind());
989
990  // Set the callee in the CallExpr.
991  // FIXME: This leaks the original parens and implicit casts.
992  ExprResult PromotedCall = UsualUnaryConversions(NewDRE);
993  if (PromotedCall.isInvalid())
994    return ExprError();
995  TheCall->setCallee(PromotedCall.take());
996
997  // Change the result type of the call to match the original value type. This
998  // is arbitrary, but the codegen for these builtins ins design to handle it
999  // gracefully.
1000  TheCall->setType(ResultType);
1001
1002  return move(TheCallResult);
1003}
1004
1005/// CheckObjCString - Checks that the argument to the builtin
1006/// CFString constructor is correct
1007/// Note: It might also make sense to do the UTF-16 conversion here (would
1008/// simplify the backend).
1009bool Sema::CheckObjCString(Expr *Arg) {
1010  Arg = Arg->IgnoreParenCasts();
1011  StringLiteral *Literal = dyn_cast<StringLiteral>(Arg);
1012
1013  if (!Literal || !Literal->isAscii()) {
1014    Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant)
1015      << Arg->getSourceRange();
1016    return true;
1017  }
1018
1019  if (Literal->containsNonAsciiOrNull()) {
1020    StringRef String = Literal->getString();
1021    unsigned NumBytes = String.size();
1022    SmallVector<UTF16, 128> ToBuf(NumBytes);
1023    const UTF8 *FromPtr = (UTF8 *)String.data();
1024    UTF16 *ToPtr = &ToBuf[0];
1025
1026    ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes,
1027                                                 &ToPtr, ToPtr + NumBytes,
1028                                                 strictConversion);
1029    // Check for conversion failure.
1030    if (Result != conversionOK)
1031      Diag(Arg->getLocStart(),
1032           diag::warn_cfstring_truncated) << Arg->getSourceRange();
1033  }
1034  return false;
1035}
1036
1037/// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity.
1038/// Emit an error and return true on failure, return false on success.
1039bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) {
1040  Expr *Fn = TheCall->getCallee();
1041  if (TheCall->getNumArgs() > 2) {
1042    Diag(TheCall->getArg(2)->getLocStart(),
1043         diag::err_typecheck_call_too_many_args)
1044      << 0 /*function call*/ << 2 << TheCall->getNumArgs()
1045      << Fn->getSourceRange()
1046      << SourceRange(TheCall->getArg(2)->getLocStart(),
1047                     (*(TheCall->arg_end()-1))->getLocEnd());
1048    return true;
1049  }
1050
1051  if (TheCall->getNumArgs() < 2) {
1052    return Diag(TheCall->getLocEnd(),
1053      diag::err_typecheck_call_too_few_args_at_least)
1054      << 0 /*function call*/ << 2 << TheCall->getNumArgs();
1055  }
1056
1057  // Type-check the first argument normally.
1058  if (checkBuiltinArgument(*this, TheCall, 0))
1059    return true;
1060
1061  // Determine whether the current function is variadic or not.
1062  BlockScopeInfo *CurBlock = getCurBlock();
1063  bool isVariadic;
1064  if (CurBlock)
1065    isVariadic = CurBlock->TheDecl->isVariadic();
1066  else if (FunctionDecl *FD = getCurFunctionDecl())
1067    isVariadic = FD->isVariadic();
1068  else
1069    isVariadic = getCurMethodDecl()->isVariadic();
1070
1071  if (!isVariadic) {
1072    Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function);
1073    return true;
1074  }
1075
1076  // Verify that the second argument to the builtin is the last argument of the
1077  // current function or method.
1078  bool SecondArgIsLastNamedArgument = false;
1079  const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts();
1080
1081  if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) {
1082    if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) {
1083      // FIXME: This isn't correct for methods (results in bogus warning).
1084      // Get the last formal in the current function.
1085      const ParmVarDecl *LastArg;
1086      if (CurBlock)
1087        LastArg = *(CurBlock->TheDecl->param_end()-1);
1088      else if (FunctionDecl *FD = getCurFunctionDecl())
1089        LastArg = *(FD->param_end()-1);
1090      else
1091        LastArg = *(getCurMethodDecl()->param_end()-1);
1092      SecondArgIsLastNamedArgument = PV == LastArg;
1093    }
1094  }
1095
1096  if (!SecondArgIsLastNamedArgument)
1097    Diag(TheCall->getArg(1)->getLocStart(),
1098         diag::warn_second_parameter_of_va_start_not_last_named_argument);
1099  return false;
1100}
1101
1102/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and
1103/// friends.  This is declared to take (...), so we have to check everything.
1104bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) {
1105  if (TheCall->getNumArgs() < 2)
1106    return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
1107      << 0 << 2 << TheCall->getNumArgs()/*function call*/;
1108  if (TheCall->getNumArgs() > 2)
1109    return Diag(TheCall->getArg(2)->getLocStart(),
1110                diag::err_typecheck_call_too_many_args)
1111      << 0 /*function call*/ << 2 << TheCall->getNumArgs()
1112      << SourceRange(TheCall->getArg(2)->getLocStart(),
1113                     (*(TheCall->arg_end()-1))->getLocEnd());
1114
1115  ExprResult OrigArg0 = TheCall->getArg(0);
1116  ExprResult OrigArg1 = TheCall->getArg(1);
1117
1118  // Do standard promotions between the two arguments, returning their common
1119  // type.
1120  QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false);
1121  if (OrigArg0.isInvalid() || OrigArg1.isInvalid())
1122    return true;
1123
1124  // Make sure any conversions are pushed back into the call; this is
1125  // type safe since unordered compare builtins are declared as "_Bool
1126  // foo(...)".
1127  TheCall->setArg(0, OrigArg0.get());
1128  TheCall->setArg(1, OrigArg1.get());
1129
1130  if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent())
1131    return false;
1132
1133  // If the common type isn't a real floating type, then the arguments were
1134  // invalid for this operation.
1135  if (!Res->isRealFloatingType())
1136    return Diag(OrigArg0.get()->getLocStart(),
1137                diag::err_typecheck_call_invalid_ordered_compare)
1138      << OrigArg0.get()->getType() << OrigArg1.get()->getType()
1139      << SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd());
1140
1141  return false;
1142}
1143
1144/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like
1145/// __builtin_isnan and friends.  This is declared to take (...), so we have
1146/// to check everything. We expect the last argument to be a floating point
1147/// value.
1148bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) {
1149  if (TheCall->getNumArgs() < NumArgs)
1150    return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
1151      << 0 << NumArgs << TheCall->getNumArgs()/*function call*/;
1152  if (TheCall->getNumArgs() > NumArgs)
1153    return Diag(TheCall->getArg(NumArgs)->getLocStart(),
1154                diag::err_typecheck_call_too_many_args)
1155      << 0 /*function call*/ << NumArgs << TheCall->getNumArgs()
1156      << SourceRange(TheCall->getArg(NumArgs)->getLocStart(),
1157                     (*(TheCall->arg_end()-1))->getLocEnd());
1158
1159  Expr *OrigArg = TheCall->getArg(NumArgs-1);
1160
1161  if (OrigArg->isTypeDependent())
1162    return false;
1163
1164  // This operation requires a non-_Complex floating-point number.
1165  if (!OrigArg->getType()->isRealFloatingType())
1166    return Diag(OrigArg->getLocStart(),
1167                diag::err_typecheck_call_invalid_unary_fp)
1168      << OrigArg->getType() << OrigArg->getSourceRange();
1169
1170  // If this is an implicit conversion from float -> double, remove it.
1171  if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) {
1172    Expr *CastArg = Cast->getSubExpr();
1173    if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) {
1174      assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) &&
1175             "promotion from float to double is the only expected cast here");
1176      Cast->setSubExpr(0);
1177      TheCall->setArg(NumArgs-1, CastArg);
1178      OrigArg = CastArg;
1179    }
1180  }
1181
1182  return false;
1183}
1184
1185/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector.
1186// This is declared to take (...), so we have to check everything.
1187ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) {
1188  if (TheCall->getNumArgs() < 2)
1189    return ExprError(Diag(TheCall->getLocEnd(),
1190                          diag::err_typecheck_call_too_few_args_at_least)
1191      << 0 /*function call*/ << 2 << TheCall->getNumArgs()
1192      << TheCall->getSourceRange());
1193
1194  // Determine which of the following types of shufflevector we're checking:
1195  // 1) unary, vector mask: (lhs, mask)
1196  // 2) binary, vector mask: (lhs, rhs, mask)
1197  // 3) binary, scalar mask: (lhs, rhs, index, ..., index)
1198  QualType resType = TheCall->getArg(0)->getType();
1199  unsigned numElements = 0;
1200
1201  if (!TheCall->getArg(0)->isTypeDependent() &&
1202      !TheCall->getArg(1)->isTypeDependent()) {
1203    QualType LHSType = TheCall->getArg(0)->getType();
1204    QualType RHSType = TheCall->getArg(1)->getType();
1205
1206    if (!LHSType->isVectorType() || !RHSType->isVectorType()) {
1207      Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector)
1208        << SourceRange(TheCall->getArg(0)->getLocStart(),
1209                       TheCall->getArg(1)->getLocEnd());
1210      return ExprError();
1211    }
1212
1213    numElements = LHSType->getAs<VectorType>()->getNumElements();
1214    unsigned numResElements = TheCall->getNumArgs() - 2;
1215
1216    // Check to see if we have a call with 2 vector arguments, the unary shuffle
1217    // with mask.  If so, verify that RHS is an integer vector type with the
1218    // same number of elts as lhs.
1219    if (TheCall->getNumArgs() == 2) {
1220      if (!RHSType->hasIntegerRepresentation() ||
1221          RHSType->getAs<VectorType>()->getNumElements() != numElements)
1222        Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector)
1223          << SourceRange(TheCall->getArg(1)->getLocStart(),
1224                         TheCall->getArg(1)->getLocEnd());
1225      numResElements = numElements;
1226    }
1227    else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) {
1228      Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector)
1229        << SourceRange(TheCall->getArg(0)->getLocStart(),
1230                       TheCall->getArg(1)->getLocEnd());
1231      return ExprError();
1232    } else if (numElements != numResElements) {
1233      QualType eltType = LHSType->getAs<VectorType>()->getElementType();
1234      resType = Context.getVectorType(eltType, numResElements,
1235                                      VectorType::GenericVector);
1236    }
1237  }
1238
1239  for (unsigned i = 2; i < TheCall->getNumArgs(); i++) {
1240    if (TheCall->getArg(i)->isTypeDependent() ||
1241        TheCall->getArg(i)->isValueDependent())
1242      continue;
1243
1244    llvm::APSInt Result(32);
1245    if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context))
1246      return ExprError(Diag(TheCall->getLocStart(),
1247                  diag::err_shufflevector_nonconstant_argument)
1248                << TheCall->getArg(i)->getSourceRange());
1249
1250    if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2)
1251      return ExprError(Diag(TheCall->getLocStart(),
1252                  diag::err_shufflevector_argument_too_large)
1253               << TheCall->getArg(i)->getSourceRange());
1254  }
1255
1256  SmallVector<Expr*, 32> exprs;
1257
1258  for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) {
1259    exprs.push_back(TheCall->getArg(i));
1260    TheCall->setArg(i, 0);
1261  }
1262
1263  return Owned(new (Context) ShuffleVectorExpr(Context, exprs.begin(),
1264                                            exprs.size(), resType,
1265                                            TheCall->getCallee()->getLocStart(),
1266                                            TheCall->getRParenLoc()));
1267}
1268
1269/// SemaBuiltinPrefetch - Handle __builtin_prefetch.
1270// This is declared to take (const void*, ...) and can take two
1271// optional constant int args.
1272bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) {
1273  unsigned NumArgs = TheCall->getNumArgs();
1274
1275  if (NumArgs > 3)
1276    return Diag(TheCall->getLocEnd(),
1277             diag::err_typecheck_call_too_many_args_at_most)
1278             << 0 /*function call*/ << 3 << NumArgs
1279             << TheCall->getSourceRange();
1280
1281  // Argument 0 is checked for us and the remaining arguments must be
1282  // constant integers.
1283  for (unsigned i = 1; i != NumArgs; ++i) {
1284    Expr *Arg = TheCall->getArg(i);
1285
1286    llvm::APSInt Result;
1287    if (SemaBuiltinConstantArg(TheCall, i, Result))
1288      return true;
1289
1290    // FIXME: gcc issues a warning and rewrites these to 0. These
1291    // seems especially odd for the third argument since the default
1292    // is 3.
1293    if (i == 1) {
1294      if (Result.getLimitedValue() > 1)
1295        return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
1296             << "0" << "1" << Arg->getSourceRange();
1297    } else {
1298      if (Result.getLimitedValue() > 3)
1299        return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
1300            << "0" << "3" << Arg->getSourceRange();
1301    }
1302  }
1303
1304  return false;
1305}
1306
1307/// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr
1308/// TheCall is a constant expression.
1309bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum,
1310                                  llvm::APSInt &Result) {
1311  Expr *Arg = TheCall->getArg(ArgNum);
1312  DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
1313  FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
1314
1315  if (Arg->isTypeDependent() || Arg->isValueDependent()) return false;
1316
1317  if (!Arg->isIntegerConstantExpr(Result, Context))
1318    return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type)
1319                << FDecl->getDeclName() <<  Arg->getSourceRange();
1320
1321  return false;
1322}
1323
1324/// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr,
1325/// int type). This simply type checks that type is one of the defined
1326/// constants (0-3).
1327// For compatibility check 0-3, llvm only handles 0 and 2.
1328bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) {
1329  llvm::APSInt Result;
1330
1331  // Check constant-ness first.
1332  if (SemaBuiltinConstantArg(TheCall, 1, Result))
1333    return true;
1334
1335  Expr *Arg = TheCall->getArg(1);
1336  if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) {
1337    return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
1338             << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
1339  }
1340
1341  return false;
1342}
1343
1344/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val).
1345/// This checks that val is a constant 1.
1346bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) {
1347  Expr *Arg = TheCall->getArg(1);
1348  llvm::APSInt Result;
1349
1350  // TODO: This is less than ideal. Overload this to take a value.
1351  if (SemaBuiltinConstantArg(TheCall, 1, Result))
1352    return true;
1353
1354  if (Result != 1)
1355    return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val)
1356             << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
1357
1358  return false;
1359}
1360
1361// Handle i > 1 ? "x" : "y", recursively.
1362bool Sema::SemaCheckStringLiteral(const Expr *E, Expr **Args,
1363                                  unsigned NumArgs, bool HasVAListArg,
1364                                  unsigned format_idx, unsigned firstDataArg,
1365                                  FormatStringType Type, bool inFunctionCall) {
1366 tryAgain:
1367  if (E->isTypeDependent() || E->isValueDependent())
1368    return false;
1369
1370  E = E->IgnoreParenCasts();
1371
1372  if (E->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull))
1373    // Technically -Wformat-nonliteral does not warn about this case.
1374    // The behavior of printf and friends in this case is implementation
1375    // dependent.  Ideally if the format string cannot be null then
1376    // it should have a 'nonnull' attribute in the function prototype.
1377    return true;
1378
1379  switch (E->getStmtClass()) {
1380  case Stmt::BinaryConditionalOperatorClass:
1381  case Stmt::ConditionalOperatorClass: {
1382    const AbstractConditionalOperator *C = cast<AbstractConditionalOperator>(E);
1383    return SemaCheckStringLiteral(C->getTrueExpr(), Args, NumArgs, HasVAListArg,
1384                                  format_idx, firstDataArg, Type,
1385                                  inFunctionCall)
1386       && SemaCheckStringLiteral(C->getFalseExpr(), Args, NumArgs, HasVAListArg,
1387                                 format_idx, firstDataArg, Type,
1388                                 inFunctionCall);
1389  }
1390
1391  case Stmt::ImplicitCastExprClass: {
1392    E = cast<ImplicitCastExpr>(E)->getSubExpr();
1393    goto tryAgain;
1394  }
1395
1396  case Stmt::OpaqueValueExprClass:
1397    if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) {
1398      E = src;
1399      goto tryAgain;
1400    }
1401    return false;
1402
1403  case Stmt::PredefinedExprClass:
1404    // While __func__, etc., are technically not string literals, they
1405    // cannot contain format specifiers and thus are not a security
1406    // liability.
1407    return true;
1408
1409  case Stmt::DeclRefExprClass: {
1410    const DeclRefExpr *DR = cast<DeclRefExpr>(E);
1411
1412    // As an exception, do not flag errors for variables binding to
1413    // const string literals.
1414    if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
1415      bool isConstant = false;
1416      QualType T = DR->getType();
1417
1418      if (const ArrayType *AT = Context.getAsArrayType(T)) {
1419        isConstant = AT->getElementType().isConstant(Context);
1420      } else if (const PointerType *PT = T->getAs<PointerType>()) {
1421        isConstant = T.isConstant(Context) &&
1422                     PT->getPointeeType().isConstant(Context);
1423      } else if (T->isObjCObjectPointerType()) {
1424        // In ObjC, there is usually no "const ObjectPointer" type,
1425        // so don't check if the pointee type is constant.
1426        isConstant = T.isConstant(Context);
1427      }
1428
1429      if (isConstant) {
1430        if (const Expr *Init = VD->getAnyInitializer())
1431          return SemaCheckStringLiteral(Init, Args, NumArgs,
1432                                        HasVAListArg, format_idx, firstDataArg,
1433                                        Type, /*inFunctionCall*/false);
1434      }
1435
1436      // For vprintf* functions (i.e., HasVAListArg==true), we add a
1437      // special check to see if the format string is a function parameter
1438      // of the function calling the printf function.  If the function
1439      // has an attribute indicating it is a printf-like function, then we
1440      // should suppress warnings concerning non-literals being used in a call
1441      // to a vprintf function.  For example:
1442      //
1443      // void
1444      // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){
1445      //      va_list ap;
1446      //      va_start(ap, fmt);
1447      //      vprintf(fmt, ap);  // Do NOT emit a warning about "fmt".
1448      //      ...
1449      //
1450      //
1451      //  FIXME: We don't have full attribute support yet, so just check to see
1452      //    if the argument is a DeclRefExpr that references a parameter.  We'll
1453      //    add proper support for checking the attribute later.
1454      if (HasVAListArg)
1455        if (isa<ParmVarDecl>(VD))
1456          return true;
1457    }
1458
1459    return false;
1460  }
1461
1462  case Stmt::CallExprClass:
1463  case Stmt::CXXMemberCallExprClass: {
1464    const CallExpr *CE = cast<CallExpr>(E);
1465    if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) {
1466      if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) {
1467        unsigned ArgIndex = FA->getFormatIdx();
1468        if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
1469          if (MD->isInstance())
1470            --ArgIndex;
1471        const Expr *Arg = CE->getArg(ArgIndex - 1);
1472
1473        return SemaCheckStringLiteral(Arg, Args, NumArgs, HasVAListArg,
1474                                      format_idx, firstDataArg, Type,
1475                                      inFunctionCall);
1476      }
1477    }
1478
1479    return false;
1480  }
1481  case Stmt::ObjCStringLiteralClass:
1482  case Stmt::StringLiteralClass: {
1483    const StringLiteral *StrE = NULL;
1484
1485    if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E))
1486      StrE = ObjCFExpr->getString();
1487    else
1488      StrE = cast<StringLiteral>(E);
1489
1490    if (StrE) {
1491      CheckFormatString(StrE, E, Args, NumArgs, HasVAListArg, format_idx,
1492                        firstDataArg, Type, inFunctionCall);
1493      return true;
1494    }
1495
1496    return false;
1497  }
1498
1499  default:
1500    return false;
1501  }
1502}
1503
1504void
1505Sema::CheckNonNullArguments(const NonNullAttr *NonNull,
1506                            const Expr * const *ExprArgs,
1507                            SourceLocation CallSiteLoc) {
1508  for (NonNullAttr::args_iterator i = NonNull->args_begin(),
1509                                  e = NonNull->args_end();
1510       i != e; ++i) {
1511    const Expr *ArgExpr = ExprArgs[*i];
1512    if (ArgExpr->isNullPointerConstant(Context,
1513                                       Expr::NPC_ValueDependentIsNotNull))
1514      Diag(CallSiteLoc, diag::warn_null_arg) << ArgExpr->getSourceRange();
1515  }
1516}
1517
1518Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) {
1519  return llvm::StringSwitch<FormatStringType>(Format->getType())
1520  .Case("scanf", FST_Scanf)
1521  .Cases("printf", "printf0", FST_Printf)
1522  .Cases("NSString", "CFString", FST_NSString)
1523  .Case("strftime", FST_Strftime)
1524  .Case("strfmon", FST_Strfmon)
1525  .Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf)
1526  .Default(FST_Unknown);
1527}
1528
1529/// CheckPrintfScanfArguments - Check calls to printf and scanf (and similar
1530/// functions) for correct use of format strings.
1531void Sema::CheckFormatArguments(const FormatAttr *Format, CallExpr *TheCall) {
1532  bool IsCXXMember = false;
1533  // The way the format attribute works in GCC, the implicit this argument
1534  // of member functions is counted. However, it doesn't appear in our own
1535  // lists, so decrement format_idx in that case.
1536  IsCXXMember = isa<CXXMemberCallExpr>(TheCall);
1537  CheckFormatArguments(Format, TheCall->getArgs(), TheCall->getNumArgs(),
1538                       IsCXXMember, TheCall->getRParenLoc(),
1539                       TheCall->getCallee()->getSourceRange());
1540}
1541
1542void Sema::CheckFormatArguments(const FormatAttr *Format, Expr **Args,
1543                                unsigned NumArgs, bool IsCXXMember,
1544                                SourceLocation Loc, SourceRange Range) {
1545  bool HasVAListArg = Format->getFirstArg() == 0;
1546  unsigned format_idx = Format->getFormatIdx() - 1;
1547  unsigned firstDataArg = HasVAListArg ? 0 : Format->getFirstArg() - 1;
1548  if (IsCXXMember) {
1549    if (format_idx == 0)
1550      return;
1551    --format_idx;
1552    if(firstDataArg != 0)
1553      --firstDataArg;
1554  }
1555  CheckFormatArguments(Args, NumArgs, HasVAListArg, format_idx,
1556                       firstDataArg, GetFormatStringType(Format), Loc, Range);
1557}
1558
1559void Sema::CheckFormatArguments(Expr **Args, unsigned NumArgs,
1560                                bool HasVAListArg, unsigned format_idx,
1561                                unsigned firstDataArg, FormatStringType Type,
1562                                SourceLocation Loc, SourceRange Range) {
1563  // CHECK: printf/scanf-like function is called with no format string.
1564  if (format_idx >= NumArgs) {
1565    Diag(Loc, diag::warn_missing_format_string) << Range;
1566    return;
1567  }
1568
1569  const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts();
1570
1571  // CHECK: format string is not a string literal.
1572  //
1573  // Dynamically generated format strings are difficult to
1574  // automatically vet at compile time.  Requiring that format strings
1575  // are string literals: (1) permits the checking of format strings by
1576  // the compiler and thereby (2) can practically remove the source of
1577  // many format string exploits.
1578
1579  // Format string can be either ObjC string (e.g. @"%d") or
1580  // C string (e.g. "%d")
1581  // ObjC string uses the same format specifiers as C string, so we can use
1582  // the same format string checking logic for both ObjC and C strings.
1583  if (SemaCheckStringLiteral(OrigFormatExpr, Args, NumArgs, HasVAListArg,
1584                             format_idx, firstDataArg, Type))
1585    return;  // Literal format string found, check done!
1586
1587  // Strftime is particular as it always uses a single 'time' argument,
1588  // so it is safe to pass a non-literal string.
1589  if (Type == FST_Strftime)
1590    return;
1591
1592  // Do not emit diag when the string param is a macro expansion and the
1593  // format is either NSString or CFString. This is a hack to prevent
1594  // diag when using the NSLocalizedString and CFCopyLocalizedString macros
1595  // which are usually used in place of NS and CF string literals.
1596  if (Type == FST_NSString && Args[format_idx]->getLocStart().isMacroID())
1597    return;
1598
1599  // If there are no arguments specified, warn with -Wformat-security, otherwise
1600  // warn only with -Wformat-nonliteral.
1601  if (NumArgs == format_idx+1)
1602    Diag(Args[format_idx]->getLocStart(),
1603         diag::warn_format_nonliteral_noargs)
1604      << OrigFormatExpr->getSourceRange();
1605  else
1606    Diag(Args[format_idx]->getLocStart(),
1607         diag::warn_format_nonliteral)
1608           << OrigFormatExpr->getSourceRange();
1609}
1610
1611namespace {
1612class CheckFormatHandler : public analyze_format_string::FormatStringHandler {
1613protected:
1614  Sema &S;
1615  const StringLiteral *FExpr;
1616  const Expr *OrigFormatExpr;
1617  const unsigned FirstDataArg;
1618  const unsigned NumDataArgs;
1619  const bool IsObjCLiteral;
1620  const char *Beg; // Start of format string.
1621  const bool HasVAListArg;
1622  const Expr * const *Args;
1623  const unsigned NumArgs;
1624  unsigned FormatIdx;
1625  llvm::BitVector CoveredArgs;
1626  bool usesPositionalArgs;
1627  bool atFirstArg;
1628  bool inFunctionCall;
1629public:
1630  CheckFormatHandler(Sema &s, const StringLiteral *fexpr,
1631                     const Expr *origFormatExpr, unsigned firstDataArg,
1632                     unsigned numDataArgs, bool isObjCLiteral,
1633                     const char *beg, bool hasVAListArg,
1634                     Expr **args, unsigned numArgs,
1635                     unsigned formatIdx, bool inFunctionCall)
1636    : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr),
1637      FirstDataArg(firstDataArg),
1638      NumDataArgs(numDataArgs),
1639      IsObjCLiteral(isObjCLiteral), Beg(beg),
1640      HasVAListArg(hasVAListArg),
1641      Args(args), NumArgs(numArgs), FormatIdx(formatIdx),
1642      usesPositionalArgs(false), atFirstArg(true),
1643      inFunctionCall(inFunctionCall) {
1644        CoveredArgs.resize(numDataArgs);
1645        CoveredArgs.reset();
1646      }
1647
1648  void DoneProcessing();
1649
1650  void HandleIncompleteSpecifier(const char *startSpecifier,
1651                                 unsigned specifierLen);
1652
1653  virtual void HandleInvalidPosition(const char *startSpecifier,
1654                                     unsigned specifierLen,
1655                                     analyze_format_string::PositionContext p);
1656
1657  virtual void HandleZeroPosition(const char *startPos, unsigned posLen);
1658
1659  void HandleNullChar(const char *nullCharacter);
1660
1661  template <typename Range>
1662  static void EmitFormatDiagnostic(Sema &S, bool inFunctionCall,
1663                                   const Expr *ArgumentExpr,
1664                                   PartialDiagnostic PDiag,
1665                                   SourceLocation StringLoc,
1666                                   bool IsStringLocation, Range StringRange,
1667                                   FixItHint Fixit = FixItHint());
1668
1669protected:
1670  bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc,
1671                                        const char *startSpec,
1672                                        unsigned specifierLen,
1673                                        const char *csStart, unsigned csLen);
1674
1675  void HandlePositionalNonpositionalArgs(SourceLocation Loc,
1676                                         const char *startSpec,
1677                                         unsigned specifierLen);
1678
1679  SourceRange getFormatStringRange();
1680  CharSourceRange getSpecifierRange(const char *startSpecifier,
1681                                    unsigned specifierLen);
1682  SourceLocation getLocationOfByte(const char *x);
1683
1684  const Expr *getDataArg(unsigned i) const;
1685
1686  bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS,
1687                    const analyze_format_string::ConversionSpecifier &CS,
1688                    const char *startSpecifier, unsigned specifierLen,
1689                    unsigned argIndex);
1690
1691  template <typename Range>
1692  void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc,
1693                            bool IsStringLocation, Range StringRange,
1694                            FixItHint Fixit = FixItHint());
1695
1696  void CheckPositionalAndNonpositionalArgs(
1697      const analyze_format_string::FormatSpecifier *FS);
1698};
1699}
1700
1701SourceRange CheckFormatHandler::getFormatStringRange() {
1702  return OrigFormatExpr->getSourceRange();
1703}
1704
1705CharSourceRange CheckFormatHandler::
1706getSpecifierRange(const char *startSpecifier, unsigned specifierLen) {
1707  SourceLocation Start = getLocationOfByte(startSpecifier);
1708  SourceLocation End   = getLocationOfByte(startSpecifier + specifierLen - 1);
1709
1710  // Advance the end SourceLocation by one due to half-open ranges.
1711  End = End.getLocWithOffset(1);
1712
1713  return CharSourceRange::getCharRange(Start, End);
1714}
1715
1716SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) {
1717  return S.getLocationOfStringLiteralByte(FExpr, x - Beg);
1718}
1719
1720void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier,
1721                                                   unsigned specifierLen){
1722  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier),
1723                       getLocationOfByte(startSpecifier),
1724                       /*IsStringLocation*/true,
1725                       getSpecifierRange(startSpecifier, specifierLen));
1726}
1727
1728void
1729CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen,
1730                                     analyze_format_string::PositionContext p) {
1731  EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier)
1732                         << (unsigned) p,
1733                       getLocationOfByte(startPos), /*IsStringLocation*/true,
1734                       getSpecifierRange(startPos, posLen));
1735}
1736
1737void CheckFormatHandler::HandleZeroPosition(const char *startPos,
1738                                            unsigned posLen) {
1739  EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier),
1740                               getLocationOfByte(startPos),
1741                               /*IsStringLocation*/true,
1742                               getSpecifierRange(startPos, posLen));
1743}
1744
1745void CheckFormatHandler::HandleNullChar(const char *nullCharacter) {
1746  if (!IsObjCLiteral) {
1747    // The presence of a null character is likely an error.
1748    EmitFormatDiagnostic(
1749      S.PDiag(diag::warn_printf_format_string_contains_null_char),
1750      getLocationOfByte(nullCharacter), /*IsStringLocation*/true,
1751      getFormatStringRange());
1752  }
1753}
1754
1755const Expr *CheckFormatHandler::getDataArg(unsigned i) const {
1756  return Args[FirstDataArg + i];
1757}
1758
1759void CheckFormatHandler::DoneProcessing() {
1760    // Does the number of data arguments exceed the number of
1761    // format conversions in the format string?
1762  if (!HasVAListArg) {
1763      // Find any arguments that weren't covered.
1764    CoveredArgs.flip();
1765    signed notCoveredArg = CoveredArgs.find_first();
1766    if (notCoveredArg >= 0) {
1767      assert((unsigned)notCoveredArg < NumDataArgs);
1768      EmitFormatDiagnostic(S.PDiag(diag::warn_printf_data_arg_not_used),
1769                           getDataArg((unsigned) notCoveredArg)->getLocStart(),
1770                           /*IsStringLocation*/false, getFormatStringRange());
1771    }
1772  }
1773}
1774
1775bool
1776CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex,
1777                                                     SourceLocation Loc,
1778                                                     const char *startSpec,
1779                                                     unsigned specifierLen,
1780                                                     const char *csStart,
1781                                                     unsigned csLen) {
1782
1783  bool keepGoing = true;
1784  if (argIndex < NumDataArgs) {
1785    // Consider the argument coverered, even though the specifier doesn't
1786    // make sense.
1787    CoveredArgs.set(argIndex);
1788  }
1789  else {
1790    // If argIndex exceeds the number of data arguments we
1791    // don't issue a warning because that is just a cascade of warnings (and
1792    // they may have intended '%%' anyway). We don't want to continue processing
1793    // the format string after this point, however, as we will like just get
1794    // gibberish when trying to match arguments.
1795    keepGoing = false;
1796  }
1797
1798  EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion)
1799                         << StringRef(csStart, csLen),
1800                       Loc, /*IsStringLocation*/true,
1801                       getSpecifierRange(startSpec, specifierLen));
1802
1803  return keepGoing;
1804}
1805
1806void
1807CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc,
1808                                                      const char *startSpec,
1809                                                      unsigned specifierLen) {
1810  EmitFormatDiagnostic(
1811    S.PDiag(diag::warn_format_mix_positional_nonpositional_args),
1812    Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen));
1813}
1814
1815bool
1816CheckFormatHandler::CheckNumArgs(
1817  const analyze_format_string::FormatSpecifier &FS,
1818  const analyze_format_string::ConversionSpecifier &CS,
1819  const char *startSpecifier, unsigned specifierLen, unsigned argIndex) {
1820
1821  if (argIndex >= NumDataArgs) {
1822    PartialDiagnostic PDiag = FS.usesPositionalArg()
1823      ? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args)
1824           << (argIndex+1) << NumDataArgs)
1825      : S.PDiag(diag::warn_printf_insufficient_data_args);
1826    EmitFormatDiagnostic(
1827      PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true,
1828      getSpecifierRange(startSpecifier, specifierLen));
1829    return false;
1830  }
1831  return true;
1832}
1833
1834template<typename Range>
1835void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag,
1836                                              SourceLocation Loc,
1837                                              bool IsStringLocation,
1838                                              Range StringRange,
1839                                              FixItHint FixIt) {
1840  EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag,
1841                       Loc, IsStringLocation, StringRange, FixIt);
1842}
1843
1844/// \brief If the format string is not within the funcion call, emit a note
1845/// so that the function call and string are in diagnostic messages.
1846///
1847/// \param inFunctionCall if true, the format string is within the function
1848/// call and only one diagnostic message will be produced.  Otherwise, an
1849/// extra note will be emitted pointing to location of the format string.
1850///
1851/// \param ArgumentExpr the expression that is passed as the format string
1852/// argument in the function call.  Used for getting locations when two
1853/// diagnostics are emitted.
1854///
1855/// \param PDiag the callee should already have provided any strings for the
1856/// diagnostic message.  This function only adds locations and fixits
1857/// to diagnostics.
1858///
1859/// \param Loc primary location for diagnostic.  If two diagnostics are
1860/// required, one will be at Loc and a new SourceLocation will be created for
1861/// the other one.
1862///
1863/// \param IsStringLocation if true, Loc points to the format string should be
1864/// used for the note.  Otherwise, Loc points to the argument list and will
1865/// be used with PDiag.
1866///
1867/// \param StringRange some or all of the string to highlight.  This is
1868/// templated so it can accept either a CharSourceRange or a SourceRange.
1869///
1870/// \param Fixit optional fix it hint for the format string.
1871template<typename Range>
1872void CheckFormatHandler::EmitFormatDiagnostic(Sema &S, bool InFunctionCall,
1873                                              const Expr *ArgumentExpr,
1874                                              PartialDiagnostic PDiag,
1875                                              SourceLocation Loc,
1876                                              bool IsStringLocation,
1877                                              Range StringRange,
1878                                              FixItHint FixIt) {
1879  if (InFunctionCall)
1880    S.Diag(Loc, PDiag) << StringRange << FixIt;
1881  else {
1882    S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag)
1883      << ArgumentExpr->getSourceRange();
1884    S.Diag(IsStringLocation ? Loc : StringRange.getBegin(),
1885           diag::note_format_string_defined)
1886      << StringRange << FixIt;
1887  }
1888}
1889
1890//===--- CHECK: Printf format string checking ------------------------------===//
1891
1892namespace {
1893class CheckPrintfHandler : public CheckFormatHandler {
1894public:
1895  CheckPrintfHandler(Sema &s, const StringLiteral *fexpr,
1896                     const Expr *origFormatExpr, unsigned firstDataArg,
1897                     unsigned numDataArgs, bool isObjCLiteral,
1898                     const char *beg, bool hasVAListArg,
1899                     Expr **Args, unsigned NumArgs,
1900                     unsigned formatIdx, bool inFunctionCall)
1901  : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
1902                       numDataArgs, isObjCLiteral, beg, hasVAListArg,
1903                       Args, NumArgs, formatIdx, inFunctionCall) {}
1904
1905
1906  bool HandleInvalidPrintfConversionSpecifier(
1907                                      const analyze_printf::PrintfSpecifier &FS,
1908                                      const char *startSpecifier,
1909                                      unsigned specifierLen);
1910
1911  bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS,
1912                             const char *startSpecifier,
1913                             unsigned specifierLen);
1914
1915  bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k,
1916                    const char *startSpecifier, unsigned specifierLen);
1917  void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS,
1918                           const analyze_printf::OptionalAmount &Amt,
1919                           unsigned type,
1920                           const char *startSpecifier, unsigned specifierLen);
1921  void HandleFlag(const analyze_printf::PrintfSpecifier &FS,
1922                  const analyze_printf::OptionalFlag &flag,
1923                  const char *startSpecifier, unsigned specifierLen);
1924  void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS,
1925                         const analyze_printf::OptionalFlag &ignoredFlag,
1926                         const analyze_printf::OptionalFlag &flag,
1927                         const char *startSpecifier, unsigned specifierLen);
1928};
1929}
1930
1931bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier(
1932                                      const analyze_printf::PrintfSpecifier &FS,
1933                                      const char *startSpecifier,
1934                                      unsigned specifierLen) {
1935  const analyze_printf::PrintfConversionSpecifier &CS =
1936    FS.getConversionSpecifier();
1937
1938  return HandleInvalidConversionSpecifier(FS.getArgIndex(),
1939                                          getLocationOfByte(CS.getStart()),
1940                                          startSpecifier, specifierLen,
1941                                          CS.getStart(), CS.getLength());
1942}
1943
1944bool CheckPrintfHandler::HandleAmount(
1945                               const analyze_format_string::OptionalAmount &Amt,
1946                               unsigned k, const char *startSpecifier,
1947                               unsigned specifierLen) {
1948
1949  if (Amt.hasDataArgument()) {
1950    if (!HasVAListArg) {
1951      unsigned argIndex = Amt.getArgIndex();
1952      if (argIndex >= NumDataArgs) {
1953        EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg)
1954                               << k,
1955                             getLocationOfByte(Amt.getStart()),
1956                             /*IsStringLocation*/true,
1957                             getSpecifierRange(startSpecifier, specifierLen));
1958        // Don't do any more checking.  We will just emit
1959        // spurious errors.
1960        return false;
1961      }
1962
1963      // Type check the data argument.  It should be an 'int'.
1964      // Although not in conformance with C99, we also allow the argument to be
1965      // an 'unsigned int' as that is a reasonably safe case.  GCC also
1966      // doesn't emit a warning for that case.
1967      CoveredArgs.set(argIndex);
1968      const Expr *Arg = getDataArg(argIndex);
1969      QualType T = Arg->getType();
1970
1971      const analyze_printf::ArgTypeResult &ATR = Amt.getArgType(S.Context);
1972      assert(ATR.isValid());
1973
1974      if (!ATR.matchesType(S.Context, T)) {
1975        EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type)
1976                               << k << ATR.getRepresentativeTypeName(S.Context)
1977                               << T << Arg->getSourceRange(),
1978                             getLocationOfByte(Amt.getStart()),
1979                             /*IsStringLocation*/true,
1980                             getSpecifierRange(startSpecifier, specifierLen));
1981        // Don't do any more checking.  We will just emit
1982        // spurious errors.
1983        return false;
1984      }
1985    }
1986  }
1987  return true;
1988}
1989
1990void CheckPrintfHandler::HandleInvalidAmount(
1991                                      const analyze_printf::PrintfSpecifier &FS,
1992                                      const analyze_printf::OptionalAmount &Amt,
1993                                      unsigned type,
1994                                      const char *startSpecifier,
1995                                      unsigned specifierLen) {
1996  const analyze_printf::PrintfConversionSpecifier &CS =
1997    FS.getConversionSpecifier();
1998
1999  FixItHint fixit =
2000    Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant
2001      ? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(),
2002                                 Amt.getConstantLength()))
2003      : FixItHint();
2004
2005  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount)
2006                         << type << CS.toString(),
2007                       getLocationOfByte(Amt.getStart()),
2008                       /*IsStringLocation*/true,
2009                       getSpecifierRange(startSpecifier, specifierLen),
2010                       fixit);
2011}
2012
2013void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS,
2014                                    const analyze_printf::OptionalFlag &flag,
2015                                    const char *startSpecifier,
2016                                    unsigned specifierLen) {
2017  // Warn about pointless flag with a fixit removal.
2018  const analyze_printf::PrintfConversionSpecifier &CS =
2019    FS.getConversionSpecifier();
2020  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag)
2021                         << flag.toString() << CS.toString(),
2022                       getLocationOfByte(flag.getPosition()),
2023                       /*IsStringLocation*/true,
2024                       getSpecifierRange(startSpecifier, specifierLen),
2025                       FixItHint::CreateRemoval(
2026                         getSpecifierRange(flag.getPosition(), 1)));
2027}
2028
2029void CheckPrintfHandler::HandleIgnoredFlag(
2030                                const analyze_printf::PrintfSpecifier &FS,
2031                                const analyze_printf::OptionalFlag &ignoredFlag,
2032                                const analyze_printf::OptionalFlag &flag,
2033                                const char *startSpecifier,
2034                                unsigned specifierLen) {
2035  // Warn about ignored flag with a fixit removal.
2036  EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag)
2037                         << ignoredFlag.toString() << flag.toString(),
2038                       getLocationOfByte(ignoredFlag.getPosition()),
2039                       /*IsStringLocation*/true,
2040                       getSpecifierRange(startSpecifier, specifierLen),
2041                       FixItHint::CreateRemoval(
2042                         getSpecifierRange(ignoredFlag.getPosition(), 1)));
2043}
2044
2045bool
2046CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier
2047                                            &FS,
2048                                          const char *startSpecifier,
2049                                          unsigned specifierLen) {
2050
2051  using namespace analyze_format_string;
2052  using namespace analyze_printf;
2053  const PrintfConversionSpecifier &CS = FS.getConversionSpecifier();
2054
2055  if (FS.consumesDataArgument()) {
2056    if (atFirstArg) {
2057        atFirstArg = false;
2058        usesPositionalArgs = FS.usesPositionalArg();
2059    }
2060    else if (usesPositionalArgs != FS.usesPositionalArg()) {
2061      HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()),
2062                                        startSpecifier, specifierLen);
2063      return false;
2064    }
2065  }
2066
2067  // First check if the field width, precision, and conversion specifier
2068  // have matching data arguments.
2069  if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0,
2070                    startSpecifier, specifierLen)) {
2071    return false;
2072  }
2073
2074  if (!HandleAmount(FS.getPrecision(), /* precision */ 1,
2075                    startSpecifier, specifierLen)) {
2076    return false;
2077  }
2078
2079  if (!CS.consumesDataArgument()) {
2080    // FIXME: Technically specifying a precision or field width here
2081    // makes no sense.  Worth issuing a warning at some point.
2082    return true;
2083  }
2084
2085  // Consume the argument.
2086  unsigned argIndex = FS.getArgIndex();
2087  if (argIndex < NumDataArgs) {
2088    // The check to see if the argIndex is valid will come later.
2089    // We set the bit here because we may exit early from this
2090    // function if we encounter some other error.
2091    CoveredArgs.set(argIndex);
2092  }
2093
2094  // Check for using an Objective-C specific conversion specifier
2095  // in a non-ObjC literal.
2096  if (!IsObjCLiteral && CS.isObjCArg()) {
2097    return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier,
2098                                                  specifierLen);
2099  }
2100
2101  // Check for invalid use of field width
2102  if (!FS.hasValidFieldWidth()) {
2103    HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0,
2104        startSpecifier, specifierLen);
2105  }
2106
2107  // Check for invalid use of precision
2108  if (!FS.hasValidPrecision()) {
2109    HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1,
2110        startSpecifier, specifierLen);
2111  }
2112
2113  // Check each flag does not conflict with any other component.
2114  if (!FS.hasValidThousandsGroupingPrefix())
2115    HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen);
2116  if (!FS.hasValidLeadingZeros())
2117    HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen);
2118  if (!FS.hasValidPlusPrefix())
2119    HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen);
2120  if (!FS.hasValidSpacePrefix())
2121    HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen);
2122  if (!FS.hasValidAlternativeForm())
2123    HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen);
2124  if (!FS.hasValidLeftJustified())
2125    HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen);
2126
2127  // Check that flags are not ignored by another flag
2128  if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+'
2129    HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(),
2130        startSpecifier, specifierLen);
2131  if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-'
2132    HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(),
2133            startSpecifier, specifierLen);
2134
2135  // Check the length modifier is valid with the given conversion specifier.
2136  const LengthModifier &LM = FS.getLengthModifier();
2137  if (!FS.hasValidLengthModifier())
2138    EmitFormatDiagnostic(S.PDiag(diag::warn_format_nonsensical_length)
2139                           << LM.toString() << CS.toString(),
2140                         getLocationOfByte(LM.getStart()),
2141                         /*IsStringLocation*/true,
2142                         getSpecifierRange(startSpecifier, specifierLen),
2143                         FixItHint::CreateRemoval(
2144                           getSpecifierRange(LM.getStart(),
2145                                             LM.getLength())));
2146
2147  // Are we using '%n'?
2148  if (CS.getKind() == ConversionSpecifier::nArg) {
2149    // Issue a warning about this being a possible security issue.
2150    EmitFormatDiagnostic(S.PDiag(diag::warn_printf_write_back),
2151                         getLocationOfByte(CS.getStart()),
2152                         /*IsStringLocation*/true,
2153                         getSpecifierRange(startSpecifier, specifierLen));
2154    // Continue checking the other format specifiers.
2155    return true;
2156  }
2157
2158  // The remaining checks depend on the data arguments.
2159  if (HasVAListArg)
2160    return true;
2161
2162  if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
2163    return false;
2164
2165  // Now type check the data expression that matches the
2166  // format specifier.
2167  const Expr *Ex = getDataArg(argIndex);
2168  const analyze_printf::ArgTypeResult &ATR = FS.getArgType(S.Context,
2169                                                           IsObjCLiteral);
2170  if (ATR.isValid() && !ATR.matchesType(S.Context, Ex->getType())) {
2171    // Check if we didn't match because of an implicit cast from a 'char'
2172    // or 'short' to an 'int'.  This is done because printf is a varargs
2173    // function.
2174    if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Ex))
2175      if (ICE->getType() == S.Context.IntTy) {
2176        // All further checking is done on the subexpression.
2177        Ex = ICE->getSubExpr();
2178        if (ATR.matchesType(S.Context, Ex->getType()))
2179          return true;
2180      }
2181
2182    // We may be able to offer a FixItHint if it is a supported type.
2183    PrintfSpecifier fixedFS = FS;
2184    bool success = fixedFS.fixType(Ex->getType(), S.getLangOptions());
2185
2186    if (success) {
2187      // Get the fix string from the fixed format specifier
2188      SmallString<128> buf;
2189      llvm::raw_svector_ostream os(buf);
2190      fixedFS.toString(os);
2191
2192      EmitFormatDiagnostic(
2193        S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
2194          << ATR.getRepresentativeTypeName(S.Context) << Ex->getType()
2195          << Ex->getSourceRange(),
2196        getLocationOfByte(CS.getStart()),
2197        /*IsStringLocation*/true,
2198        getSpecifierRange(startSpecifier, specifierLen),
2199        FixItHint::CreateReplacement(
2200          getSpecifierRange(startSpecifier, specifierLen),
2201          os.str()));
2202    }
2203    else {
2204      EmitFormatDiagnostic(
2205        S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
2206          << ATR.getRepresentativeTypeName(S.Context) << Ex->getType()
2207          << getSpecifierRange(startSpecifier, specifierLen)
2208          << Ex->getSourceRange(),
2209        getLocationOfByte(CS.getStart()),
2210        true,
2211        getSpecifierRange(startSpecifier, specifierLen));
2212    }
2213  }
2214
2215  return true;
2216}
2217
2218//===--- CHECK: Scanf format string checking ------------------------------===//
2219
2220namespace {
2221class CheckScanfHandler : public CheckFormatHandler {
2222public:
2223  CheckScanfHandler(Sema &s, const StringLiteral *fexpr,
2224                    const Expr *origFormatExpr, unsigned firstDataArg,
2225                    unsigned numDataArgs, bool isObjCLiteral,
2226                    const char *beg, bool hasVAListArg,
2227                    Expr **Args, unsigned NumArgs,
2228                    unsigned formatIdx, bool inFunctionCall)
2229  : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
2230                       numDataArgs, isObjCLiteral, beg, hasVAListArg,
2231                       Args, NumArgs, formatIdx, inFunctionCall) {}
2232
2233  bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS,
2234                            const char *startSpecifier,
2235                            unsigned specifierLen);
2236
2237  bool HandleInvalidScanfConversionSpecifier(
2238          const analyze_scanf::ScanfSpecifier &FS,
2239          const char *startSpecifier,
2240          unsigned specifierLen);
2241
2242  void HandleIncompleteScanList(const char *start, const char *end);
2243};
2244}
2245
2246void CheckScanfHandler::HandleIncompleteScanList(const char *start,
2247                                                 const char *end) {
2248  EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete),
2249                       getLocationOfByte(end), /*IsStringLocation*/true,
2250                       getSpecifierRange(start, end - start));
2251}
2252
2253bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier(
2254                                        const analyze_scanf::ScanfSpecifier &FS,
2255                                        const char *startSpecifier,
2256                                        unsigned specifierLen) {
2257
2258  const analyze_scanf::ScanfConversionSpecifier &CS =
2259    FS.getConversionSpecifier();
2260
2261  return HandleInvalidConversionSpecifier(FS.getArgIndex(),
2262                                          getLocationOfByte(CS.getStart()),
2263                                          startSpecifier, specifierLen,
2264                                          CS.getStart(), CS.getLength());
2265}
2266
2267bool CheckScanfHandler::HandleScanfSpecifier(
2268                                       const analyze_scanf::ScanfSpecifier &FS,
2269                                       const char *startSpecifier,
2270                                       unsigned specifierLen) {
2271
2272  using namespace analyze_scanf;
2273  using namespace analyze_format_string;
2274
2275  const ScanfConversionSpecifier &CS = FS.getConversionSpecifier();
2276
2277  // Handle case where '%' and '*' don't consume an argument.  These shouldn't
2278  // be used to decide if we are using positional arguments consistently.
2279  if (FS.consumesDataArgument()) {
2280    if (atFirstArg) {
2281      atFirstArg = false;
2282      usesPositionalArgs = FS.usesPositionalArg();
2283    }
2284    else if (usesPositionalArgs != FS.usesPositionalArg()) {
2285      HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()),
2286                                        startSpecifier, specifierLen);
2287      return false;
2288    }
2289  }
2290
2291  // Check if the field with is non-zero.
2292  const OptionalAmount &Amt = FS.getFieldWidth();
2293  if (Amt.getHowSpecified() == OptionalAmount::Constant) {
2294    if (Amt.getConstantAmount() == 0) {
2295      const CharSourceRange &R = getSpecifierRange(Amt.getStart(),
2296                                                   Amt.getConstantLength());
2297      EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width),
2298                           getLocationOfByte(Amt.getStart()),
2299                           /*IsStringLocation*/true, R,
2300                           FixItHint::CreateRemoval(R));
2301    }
2302  }
2303
2304  if (!FS.consumesDataArgument()) {
2305    // FIXME: Technically specifying a precision or field width here
2306    // makes no sense.  Worth issuing a warning at some point.
2307    return true;
2308  }
2309
2310  // Consume the argument.
2311  unsigned argIndex = FS.getArgIndex();
2312  if (argIndex < NumDataArgs) {
2313      // The check to see if the argIndex is valid will come later.
2314      // We set the bit here because we may exit early from this
2315      // function if we encounter some other error.
2316    CoveredArgs.set(argIndex);
2317  }
2318
2319  // Check the length modifier is valid with the given conversion specifier.
2320  const LengthModifier &LM = FS.getLengthModifier();
2321  if (!FS.hasValidLengthModifier()) {
2322    const CharSourceRange &R = getSpecifierRange(LM.getStart(), LM.getLength());
2323    EmitFormatDiagnostic(S.PDiag(diag::warn_format_nonsensical_length)
2324                         << LM.toString() << CS.toString()
2325                         << getSpecifierRange(startSpecifier, specifierLen),
2326                         getLocationOfByte(LM.getStart()),
2327                         /*IsStringLocation*/true, R,
2328                         FixItHint::CreateRemoval(R));
2329  }
2330
2331  // The remaining checks depend on the data arguments.
2332  if (HasVAListArg)
2333    return true;
2334
2335  if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
2336    return false;
2337
2338  // Check that the argument type matches the format specifier.
2339  const Expr *Ex = getDataArg(argIndex);
2340  const analyze_scanf::ScanfArgTypeResult &ATR = FS.getArgType(S.Context);
2341  if (ATR.isValid() && !ATR.matchesType(S.Context, Ex->getType())) {
2342    ScanfSpecifier fixedFS = FS;
2343    bool success = fixedFS.fixType(Ex->getType(), S.getLangOptions());
2344
2345    if (success) {
2346      // Get the fix string from the fixed format specifier.
2347      SmallString<128> buf;
2348      llvm::raw_svector_ostream os(buf);
2349      fixedFS.toString(os);
2350
2351      EmitFormatDiagnostic(
2352        S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
2353          << ATR.getRepresentativeTypeName(S.Context) << Ex->getType()
2354          << Ex->getSourceRange(),
2355        getLocationOfByte(CS.getStart()),
2356        /*IsStringLocation*/true,
2357        getSpecifierRange(startSpecifier, specifierLen),
2358        FixItHint::CreateReplacement(
2359          getSpecifierRange(startSpecifier, specifierLen),
2360          os.str()));
2361    } else {
2362      EmitFormatDiagnostic(
2363        S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
2364          << ATR.getRepresentativeTypeName(S.Context) << Ex->getType()
2365          << Ex->getSourceRange(),
2366        getLocationOfByte(CS.getStart()),
2367        /*IsStringLocation*/true,
2368        getSpecifierRange(startSpecifier, specifierLen));
2369    }
2370  }
2371
2372  return true;
2373}
2374
2375void Sema::CheckFormatString(const StringLiteral *FExpr,
2376                             const Expr *OrigFormatExpr,
2377                             Expr **Args, unsigned NumArgs,
2378                             bool HasVAListArg, unsigned format_idx,
2379                             unsigned firstDataArg, FormatStringType Type,
2380                             bool inFunctionCall) {
2381
2382  // CHECK: is the format string a wide literal?
2383  if (!FExpr->isAscii()) {
2384    CheckFormatHandler::EmitFormatDiagnostic(
2385      *this, inFunctionCall, Args[format_idx],
2386      PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(),
2387      /*IsStringLocation*/true, OrigFormatExpr->getSourceRange());
2388    return;
2389  }
2390
2391  // Str - The format string.  NOTE: this is NOT null-terminated!
2392  StringRef StrRef = FExpr->getString();
2393  const char *Str = StrRef.data();
2394  unsigned StrLen = StrRef.size();
2395  const unsigned numDataArgs = NumArgs - firstDataArg;
2396
2397  // CHECK: empty format string?
2398  if (StrLen == 0 && numDataArgs > 0) {
2399    CheckFormatHandler::EmitFormatDiagnostic(
2400      *this, inFunctionCall, Args[format_idx],
2401      PDiag(diag::warn_empty_format_string), FExpr->getLocStart(),
2402      /*IsStringLocation*/true, OrigFormatExpr->getSourceRange());
2403    return;
2404  }
2405
2406  if (Type == FST_Printf || Type == FST_NSString) {
2407    CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg,
2408                         numDataArgs, isa<ObjCStringLiteral>(OrigFormatExpr),
2409                         Str, HasVAListArg, Args, NumArgs, format_idx,
2410                         inFunctionCall);
2411
2412    if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen,
2413                                                  getLangOptions()))
2414      H.DoneProcessing();
2415  } else if (Type == FST_Scanf) {
2416    CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg,
2417                        numDataArgs, isa<ObjCStringLiteral>(OrigFormatExpr),
2418                        Str, HasVAListArg, Args, NumArgs, format_idx,
2419                        inFunctionCall);
2420
2421    if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen,
2422                                                 getLangOptions()))
2423      H.DoneProcessing();
2424  } // TODO: handle other formats
2425}
2426
2427//===--- CHECK: Standard memory functions ---------------------------------===//
2428
2429/// \brief Determine whether the given type is a dynamic class type (e.g.,
2430/// whether it has a vtable).
2431static bool isDynamicClassType(QualType T) {
2432  if (CXXRecordDecl *Record = T->getAsCXXRecordDecl())
2433    if (CXXRecordDecl *Definition = Record->getDefinition())
2434      if (Definition->isDynamicClass())
2435        return true;
2436
2437  return false;
2438}
2439
2440/// \brief If E is a sizeof expression, returns its argument expression,
2441/// otherwise returns NULL.
2442static const Expr *getSizeOfExprArg(const Expr* E) {
2443  if (const UnaryExprOrTypeTraitExpr *SizeOf =
2444      dyn_cast<UnaryExprOrTypeTraitExpr>(E))
2445    if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType())
2446      return SizeOf->getArgumentExpr()->IgnoreParenImpCasts();
2447
2448  return 0;
2449}
2450
2451/// \brief If E is a sizeof expression, returns its argument type.
2452static QualType getSizeOfArgType(const Expr* E) {
2453  if (const UnaryExprOrTypeTraitExpr *SizeOf =
2454      dyn_cast<UnaryExprOrTypeTraitExpr>(E))
2455    if (SizeOf->getKind() == clang::UETT_SizeOf)
2456      return SizeOf->getTypeOfArgument();
2457
2458  return QualType();
2459}
2460
2461/// \brief Check for dangerous or invalid arguments to memset().
2462///
2463/// This issues warnings on known problematic, dangerous or unspecified
2464/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp'
2465/// function calls.
2466///
2467/// \param Call The call expression to diagnose.
2468void Sema::CheckMemaccessArguments(const CallExpr *Call,
2469                                   unsigned BId,
2470                                   IdentifierInfo *FnName) {
2471  assert(BId != 0);
2472
2473  // It is possible to have a non-standard definition of memset.  Validate
2474  // we have enough arguments, and if not, abort further checking.
2475  unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3);
2476  if (Call->getNumArgs() < ExpectedNumArgs)
2477    return;
2478
2479  unsigned LastArg = (BId == Builtin::BImemset ||
2480                      BId == Builtin::BIstrndup ? 1 : 2);
2481  unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2);
2482  const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts();
2483
2484  // We have special checking when the length is a sizeof expression.
2485  QualType SizeOfArgTy = getSizeOfArgType(LenExpr);
2486  const Expr *SizeOfArg = getSizeOfExprArg(LenExpr);
2487  llvm::FoldingSetNodeID SizeOfArgID;
2488
2489  for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) {
2490    const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts();
2491    SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange();
2492
2493    QualType DestTy = Dest->getType();
2494    if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) {
2495      QualType PointeeTy = DestPtrTy->getPointeeType();
2496
2497      // Never warn about void type pointers. This can be used to suppress
2498      // false positives.
2499      if (PointeeTy->isVoidType())
2500        continue;
2501
2502      // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by
2503      // actually comparing the expressions for equality. Because computing the
2504      // expression IDs can be expensive, we only do this if the diagnostic is
2505      // enabled.
2506      if (SizeOfArg &&
2507          Diags.getDiagnosticLevel(diag::warn_sizeof_pointer_expr_memaccess,
2508                                   SizeOfArg->getExprLoc())) {
2509        // We only compute IDs for expressions if the warning is enabled, and
2510        // cache the sizeof arg's ID.
2511        if (SizeOfArgID == llvm::FoldingSetNodeID())
2512          SizeOfArg->Profile(SizeOfArgID, Context, true);
2513        llvm::FoldingSetNodeID DestID;
2514        Dest->Profile(DestID, Context, true);
2515        if (DestID == SizeOfArgID) {
2516          // TODO: For strncpy() and friends, this could suggest sizeof(dst)
2517          //       over sizeof(src) as well.
2518          unsigned ActionIdx = 0; // Default is to suggest dereferencing.
2519          if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest))
2520            if (UnaryOp->getOpcode() == UO_AddrOf)
2521              ActionIdx = 1; // If its an address-of operator, just remove it.
2522          if (Context.getTypeSize(PointeeTy) == Context.getCharWidth())
2523            ActionIdx = 2; // If the pointee's size is sizeof(char),
2524                           // suggest an explicit length.
2525          unsigned DestSrcSelect =
2526            (BId == Builtin::BIstrndup ? 1 : ArgIdx);
2527          DiagRuntimeBehavior(SizeOfArg->getExprLoc(), Dest,
2528                              PDiag(diag::warn_sizeof_pointer_expr_memaccess)
2529                                << FnName << DestSrcSelect << ActionIdx
2530                                << Dest->getSourceRange()
2531                                << SizeOfArg->getSourceRange());
2532          break;
2533        }
2534      }
2535
2536      // Also check for cases where the sizeof argument is the exact same
2537      // type as the memory argument, and where it points to a user-defined
2538      // record type.
2539      if (SizeOfArgTy != QualType()) {
2540        if (PointeeTy->isRecordType() &&
2541            Context.typesAreCompatible(SizeOfArgTy, DestTy)) {
2542          DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest,
2543                              PDiag(diag::warn_sizeof_pointer_type_memaccess)
2544                                << FnName << SizeOfArgTy << ArgIdx
2545                                << PointeeTy << Dest->getSourceRange()
2546                                << LenExpr->getSourceRange());
2547          break;
2548        }
2549      }
2550
2551      // Always complain about dynamic classes.
2552      if (isDynamicClassType(PointeeTy)) {
2553
2554        unsigned OperationType = 0;
2555        // "overwritten" if we're warning about the destination for any call
2556        // but memcmp; otherwise a verb appropriate to the call.
2557        if (ArgIdx != 0 || BId == Builtin::BImemcmp) {
2558          if (BId == Builtin::BImemcpy)
2559            OperationType = 1;
2560          else if(BId == Builtin::BImemmove)
2561            OperationType = 2;
2562          else if (BId == Builtin::BImemcmp)
2563            OperationType = 3;
2564        }
2565
2566        DiagRuntimeBehavior(
2567          Dest->getExprLoc(), Dest,
2568          PDiag(diag::warn_dyn_class_memaccess)
2569            << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx)
2570            << FnName << PointeeTy
2571            << OperationType
2572            << Call->getCallee()->getSourceRange());
2573      } else if (PointeeTy.hasNonTrivialObjCLifetime() &&
2574               BId != Builtin::BImemset)
2575        DiagRuntimeBehavior(
2576          Dest->getExprLoc(), Dest,
2577          PDiag(diag::warn_arc_object_memaccess)
2578            << ArgIdx << FnName << PointeeTy
2579            << Call->getCallee()->getSourceRange());
2580      else
2581        continue;
2582
2583      DiagRuntimeBehavior(
2584        Dest->getExprLoc(), Dest,
2585        PDiag(diag::note_bad_memaccess_silence)
2586          << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)"));
2587      break;
2588    }
2589  }
2590}
2591
2592// A little helper routine: ignore addition and subtraction of integer literals.
2593// This intentionally does not ignore all integer constant expressions because
2594// we don't want to remove sizeof().
2595static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) {
2596  Ex = Ex->IgnoreParenCasts();
2597
2598  for (;;) {
2599    const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex);
2600    if (!BO || !BO->isAdditiveOp())
2601      break;
2602
2603    const Expr *RHS = BO->getRHS()->IgnoreParenCasts();
2604    const Expr *LHS = BO->getLHS()->IgnoreParenCasts();
2605
2606    if (isa<IntegerLiteral>(RHS))
2607      Ex = LHS;
2608    else if (isa<IntegerLiteral>(LHS))
2609      Ex = RHS;
2610    else
2611      break;
2612  }
2613
2614  return Ex;
2615}
2616
2617// Warn if the user has made the 'size' argument to strlcpy or strlcat
2618// be the size of the source, instead of the destination.
2619void Sema::CheckStrlcpycatArguments(const CallExpr *Call,
2620                                    IdentifierInfo *FnName) {
2621
2622  // Don't crash if the user has the wrong number of arguments
2623  if (Call->getNumArgs() != 3)
2624    return;
2625
2626  const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context);
2627  const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context);
2628  const Expr *CompareWithSrc = NULL;
2629
2630  // Look for 'strlcpy(dst, x, sizeof(x))'
2631  if (const Expr *Ex = getSizeOfExprArg(SizeArg))
2632    CompareWithSrc = Ex;
2633  else {
2634    // Look for 'strlcpy(dst, x, strlen(x))'
2635    if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) {
2636      if (SizeCall->isBuiltinCall() == Builtin::BIstrlen
2637          && SizeCall->getNumArgs() == 1)
2638        CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context);
2639    }
2640  }
2641
2642  if (!CompareWithSrc)
2643    return;
2644
2645  // Determine if the argument to sizeof/strlen is equal to the source
2646  // argument.  In principle there's all kinds of things you could do
2647  // here, for instance creating an == expression and evaluating it with
2648  // EvaluateAsBooleanCondition, but this uses a more direct technique:
2649  const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg);
2650  if (!SrcArgDRE)
2651    return;
2652
2653  const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc);
2654  if (!CompareWithSrcDRE ||
2655      SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl())
2656    return;
2657
2658  const Expr *OriginalSizeArg = Call->getArg(2);
2659  Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size)
2660    << OriginalSizeArg->getSourceRange() << FnName;
2661
2662  // Output a FIXIT hint if the destination is an array (rather than a
2663  // pointer to an array).  This could be enhanced to handle some
2664  // pointers if we know the actual size, like if DstArg is 'array+2'
2665  // we could say 'sizeof(array)-2'.
2666  const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts();
2667  QualType DstArgTy = DstArg->getType();
2668
2669  // Only handle constant-sized or VLAs, but not flexible members.
2670  if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(DstArgTy)) {
2671    // Only issue the FIXIT for arrays of size > 1.
2672    if (CAT->getSize().getSExtValue() <= 1)
2673      return;
2674  } else if (!DstArgTy->isVariableArrayType()) {
2675    return;
2676  }
2677
2678  SmallString<128> sizeString;
2679  llvm::raw_svector_ostream OS(sizeString);
2680  OS << "sizeof(";
2681  DstArg->printPretty(OS, Context, 0, getPrintingPolicy());
2682  OS << ")";
2683
2684  Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size)
2685    << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(),
2686                                    OS.str());
2687}
2688
2689/// Check if two expressions refer to the same declaration.
2690static bool referToTheSameDecl(const Expr *E1, const Expr *E2) {
2691  if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1))
2692    if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2))
2693      return D1->getDecl() == D2->getDecl();
2694  return false;
2695}
2696
2697static const Expr *getStrlenExprArg(const Expr *E) {
2698  if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
2699    const FunctionDecl *FD = CE->getDirectCallee();
2700    if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen)
2701      return 0;
2702    return CE->getArg(0)->IgnoreParenCasts();
2703  }
2704  return 0;
2705}
2706
2707// Warn on anti-patterns as the 'size' argument to strncat.
2708// The correct size argument should look like following:
2709//   strncat(dst, src, sizeof(dst) - strlen(dest) - 1);
2710void Sema::CheckStrncatArguments(const CallExpr *CE,
2711                                 IdentifierInfo *FnName) {
2712  // Don't crash if the user has the wrong number of arguments.
2713  if (CE->getNumArgs() < 3)
2714    return;
2715  const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts();
2716  const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts();
2717  const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts();
2718
2719  // Identify common expressions, which are wrongly used as the size argument
2720  // to strncat and may lead to buffer overflows.
2721  unsigned PatternType = 0;
2722  if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) {
2723    // - sizeof(dst)
2724    if (referToTheSameDecl(SizeOfArg, DstArg))
2725      PatternType = 1;
2726    // - sizeof(src)
2727    else if (referToTheSameDecl(SizeOfArg, SrcArg))
2728      PatternType = 2;
2729  } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) {
2730    if (BE->getOpcode() == BO_Sub) {
2731      const Expr *L = BE->getLHS()->IgnoreParenCasts();
2732      const Expr *R = BE->getRHS()->IgnoreParenCasts();
2733      // - sizeof(dst) - strlen(dst)
2734      if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) &&
2735          referToTheSameDecl(DstArg, getStrlenExprArg(R)))
2736        PatternType = 1;
2737      // - sizeof(src) - (anything)
2738      else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L)))
2739        PatternType = 2;
2740    }
2741  }
2742
2743  if (PatternType == 0)
2744    return;
2745
2746  // Generate the diagnostic.
2747  SourceLocation SL = LenArg->getLocStart();
2748  SourceRange SR = LenArg->getSourceRange();
2749  SourceManager &SM  = PP.getSourceManager();
2750
2751  // If the function is defined as a builtin macro, do not show macro expansion.
2752  if (SM.isMacroArgExpansion(SL)) {
2753    SL = SM.getSpellingLoc(SL);
2754    SR = SourceRange(SM.getSpellingLoc(SR.getBegin()),
2755                     SM.getSpellingLoc(SR.getEnd()));
2756  }
2757
2758  if (PatternType == 1)
2759    Diag(SL, diag::warn_strncat_large_size) << SR;
2760  else
2761    Diag(SL, diag::warn_strncat_src_size) << SR;
2762
2763  // Output a FIXIT hint if the destination is an array (rather than a
2764  // pointer to an array).  This could be enhanced to handle some
2765  // pointers if we know the actual size, like if DstArg is 'array+2'
2766  // we could say 'sizeof(array)-2'.
2767  QualType DstArgTy = DstArg->getType();
2768
2769  // Only handle constant-sized or VLAs, but not flexible members.
2770  if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(DstArgTy)) {
2771    // Only issue the FIXIT for arrays of size > 1.
2772    if (CAT->getSize().getSExtValue() <= 1)
2773      return;
2774  } else if (!DstArgTy->isVariableArrayType()) {
2775    return;
2776  }
2777
2778  SmallString<128> sizeString;
2779  llvm::raw_svector_ostream OS(sizeString);
2780  OS << "sizeof(";
2781  DstArg->printPretty(OS, Context, 0, getPrintingPolicy());
2782  OS << ") - ";
2783  OS << "strlen(";
2784  DstArg->printPretty(OS, Context, 0, getPrintingPolicy());
2785  OS << ") - 1";
2786
2787  Diag(SL, diag::note_strncat_wrong_size)
2788    << FixItHint::CreateReplacement(SR, OS.str());
2789}
2790
2791//===--- CHECK: Return Address of Stack Variable --------------------------===//
2792
2793static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars);
2794static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars);
2795
2796/// CheckReturnStackAddr - Check if a return statement returns the address
2797///   of a stack variable.
2798void
2799Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType,
2800                           SourceLocation ReturnLoc) {
2801
2802  Expr *stackE = 0;
2803  SmallVector<DeclRefExpr *, 8> refVars;
2804
2805  // Perform checking for returned stack addresses, local blocks,
2806  // label addresses or references to temporaries.
2807  if (lhsType->isPointerType() ||
2808      (!getLangOptions().ObjCAutoRefCount && lhsType->isBlockPointerType())) {
2809    stackE = EvalAddr(RetValExp, refVars);
2810  } else if (lhsType->isReferenceType()) {
2811    stackE = EvalVal(RetValExp, refVars);
2812  }
2813
2814  if (stackE == 0)
2815    return; // Nothing suspicious was found.
2816
2817  SourceLocation diagLoc;
2818  SourceRange diagRange;
2819  if (refVars.empty()) {
2820    diagLoc = stackE->getLocStart();
2821    diagRange = stackE->getSourceRange();
2822  } else {
2823    // We followed through a reference variable. 'stackE' contains the
2824    // problematic expression but we will warn at the return statement pointing
2825    // at the reference variable. We will later display the "trail" of
2826    // reference variables using notes.
2827    diagLoc = refVars[0]->getLocStart();
2828    diagRange = refVars[0]->getSourceRange();
2829  }
2830
2831  if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var.
2832    Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref
2833                                             : diag::warn_ret_stack_addr)
2834     << DR->getDecl()->getDeclName() << diagRange;
2835  } else if (isa<BlockExpr>(stackE)) { // local block.
2836    Diag(diagLoc, diag::err_ret_local_block) << diagRange;
2837  } else if (isa<AddrLabelExpr>(stackE)) { // address of label.
2838    Diag(diagLoc, diag::warn_ret_addr_label) << diagRange;
2839  } else { // local temporary.
2840    Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref
2841                                             : diag::warn_ret_local_temp_addr)
2842     << diagRange;
2843  }
2844
2845  // Display the "trail" of reference variables that we followed until we
2846  // found the problematic expression using notes.
2847  for (unsigned i = 0, e = refVars.size(); i != e; ++i) {
2848    VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl());
2849    // If this var binds to another reference var, show the range of the next
2850    // var, otherwise the var binds to the problematic expression, in which case
2851    // show the range of the expression.
2852    SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange()
2853                                  : stackE->getSourceRange();
2854    Diag(VD->getLocation(), diag::note_ref_var_local_bind)
2855      << VD->getDeclName() << range;
2856  }
2857}
2858
2859/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that
2860///  check if the expression in a return statement evaluates to an address
2861///  to a location on the stack, a local block, an address of a label, or a
2862///  reference to local temporary. The recursion is used to traverse the
2863///  AST of the return expression, with recursion backtracking when we
2864///  encounter a subexpression that (1) clearly does not lead to one of the
2865///  above problematic expressions (2) is something we cannot determine leads to
2866///  a problematic expression based on such local checking.
2867///
2868///  Both EvalAddr and EvalVal follow through reference variables to evaluate
2869///  the expression that they point to. Such variables are added to the
2870///  'refVars' vector so that we know what the reference variable "trail" was.
2871///
2872///  EvalAddr processes expressions that are pointers that are used as
2873///  references (and not L-values).  EvalVal handles all other values.
2874///  At the base case of the recursion is a check for the above problematic
2875///  expressions.
2876///
2877///  This implementation handles:
2878///
2879///   * pointer-to-pointer casts
2880///   * implicit conversions from array references to pointers
2881///   * taking the address of fields
2882///   * arbitrary interplay between "&" and "*" operators
2883///   * pointer arithmetic from an address of a stack variable
2884///   * taking the address of an array element where the array is on the stack
2885static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars) {
2886  if (E->isTypeDependent())
2887      return NULL;
2888
2889  // We should only be called for evaluating pointer expressions.
2890  assert((E->getType()->isAnyPointerType() ||
2891          E->getType()->isBlockPointerType() ||
2892          E->getType()->isObjCQualifiedIdType()) &&
2893         "EvalAddr only works on pointers");
2894
2895  E = E->IgnoreParens();
2896
2897  // Our "symbolic interpreter" is just a dispatch off the currently
2898  // viewed AST node.  We then recursively traverse the AST by calling
2899  // EvalAddr and EvalVal appropriately.
2900  switch (E->getStmtClass()) {
2901  case Stmt::DeclRefExprClass: {
2902    DeclRefExpr *DR = cast<DeclRefExpr>(E);
2903
2904    if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl()))
2905      // If this is a reference variable, follow through to the expression that
2906      // it points to.
2907      if (V->hasLocalStorage() &&
2908          V->getType()->isReferenceType() && V->hasInit()) {
2909        // Add the reference variable to the "trail".
2910        refVars.push_back(DR);
2911        return EvalAddr(V->getInit(), refVars);
2912      }
2913
2914    return NULL;
2915  }
2916
2917  case Stmt::UnaryOperatorClass: {
2918    // The only unary operator that make sense to handle here
2919    // is AddrOf.  All others don't make sense as pointers.
2920    UnaryOperator *U = cast<UnaryOperator>(E);
2921
2922    if (U->getOpcode() == UO_AddrOf)
2923      return EvalVal(U->getSubExpr(), refVars);
2924    else
2925      return NULL;
2926  }
2927
2928  case Stmt::BinaryOperatorClass: {
2929    // Handle pointer arithmetic.  All other binary operators are not valid
2930    // in this context.
2931    BinaryOperator *B = cast<BinaryOperator>(E);
2932    BinaryOperatorKind op = B->getOpcode();
2933
2934    if (op != BO_Add && op != BO_Sub)
2935      return NULL;
2936
2937    Expr *Base = B->getLHS();
2938
2939    // Determine which argument is the real pointer base.  It could be
2940    // the RHS argument instead of the LHS.
2941    if (!Base->getType()->isPointerType()) Base = B->getRHS();
2942
2943    assert (Base->getType()->isPointerType());
2944    return EvalAddr(Base, refVars);
2945  }
2946
2947  // For conditional operators we need to see if either the LHS or RHS are
2948  // valid DeclRefExpr*s.  If one of them is valid, we return it.
2949  case Stmt::ConditionalOperatorClass: {
2950    ConditionalOperator *C = cast<ConditionalOperator>(E);
2951
2952    // Handle the GNU extension for missing LHS.
2953    if (Expr *lhsExpr = C->getLHS()) {
2954    // In C++, we can have a throw-expression, which has 'void' type.
2955      if (!lhsExpr->getType()->isVoidType())
2956        if (Expr* LHS = EvalAddr(lhsExpr, refVars))
2957          return LHS;
2958    }
2959
2960    // In C++, we can have a throw-expression, which has 'void' type.
2961    if (C->getRHS()->getType()->isVoidType())
2962      return NULL;
2963
2964    return EvalAddr(C->getRHS(), refVars);
2965  }
2966
2967  case Stmt::BlockExprClass:
2968    if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures())
2969      return E; // local block.
2970    return NULL;
2971
2972  case Stmt::AddrLabelExprClass:
2973    return E; // address of label.
2974
2975  case Stmt::ExprWithCleanupsClass:
2976    return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars);
2977
2978  // For casts, we need to handle conversions from arrays to
2979  // pointer values, and pointer-to-pointer conversions.
2980  case Stmt::ImplicitCastExprClass:
2981  case Stmt::CStyleCastExprClass:
2982  case Stmt::CXXFunctionalCastExprClass:
2983  case Stmt::ObjCBridgedCastExprClass: {
2984    Expr* SubExpr = cast<CastExpr>(E)->getSubExpr();
2985    QualType T = SubExpr->getType();
2986
2987    if (SubExpr->getType()->isPointerType() ||
2988        SubExpr->getType()->isBlockPointerType() ||
2989        SubExpr->getType()->isObjCQualifiedIdType())
2990      return EvalAddr(SubExpr, refVars);
2991    else if (T->isArrayType())
2992      return EvalVal(SubExpr, refVars);
2993    else
2994      return 0;
2995  }
2996
2997  // C++ casts.  For dynamic casts, static casts, and const casts, we
2998  // are always converting from a pointer-to-pointer, so we just blow
2999  // through the cast.  In the case the dynamic cast doesn't fail (and
3000  // return NULL), we take the conservative route and report cases
3001  // where we return the address of a stack variable.  For Reinterpre
3002  // FIXME: The comment about is wrong; we're not always converting
3003  // from pointer to pointer. I'm guessing that this code should also
3004  // handle references to objects.
3005  case Stmt::CXXStaticCastExprClass:
3006  case Stmt::CXXDynamicCastExprClass:
3007  case Stmt::CXXConstCastExprClass:
3008  case Stmt::CXXReinterpretCastExprClass: {
3009      Expr *S = cast<CXXNamedCastExpr>(E)->getSubExpr();
3010      if (S->getType()->isPointerType() || S->getType()->isBlockPointerType())
3011        return EvalAddr(S, refVars);
3012      else
3013        return NULL;
3014  }
3015
3016  case Stmt::MaterializeTemporaryExprClass:
3017    if (Expr *Result = EvalAddr(
3018                         cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
3019                                refVars))
3020      return Result;
3021
3022    return E;
3023
3024  // Everything else: we simply don't reason about them.
3025  default:
3026    return NULL;
3027  }
3028}
3029
3030
3031///  EvalVal - This function is complements EvalAddr in the mutual recursion.
3032///   See the comments for EvalAddr for more details.
3033static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars) {
3034do {
3035  // We should only be called for evaluating non-pointer expressions, or
3036  // expressions with a pointer type that are not used as references but instead
3037  // are l-values (e.g., DeclRefExpr with a pointer type).
3038
3039  // Our "symbolic interpreter" is just a dispatch off the currently
3040  // viewed AST node.  We then recursively traverse the AST by calling
3041  // EvalAddr and EvalVal appropriately.
3042
3043  E = E->IgnoreParens();
3044  switch (E->getStmtClass()) {
3045  case Stmt::ImplicitCastExprClass: {
3046    ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E);
3047    if (IE->getValueKind() == VK_LValue) {
3048      E = IE->getSubExpr();
3049      continue;
3050    }
3051    return NULL;
3052  }
3053
3054  case Stmt::ExprWithCleanupsClass:
3055    return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars);
3056
3057  case Stmt::DeclRefExprClass: {
3058    // When we hit a DeclRefExpr we are looking at code that refers to a
3059    // variable's name. If it's not a reference variable we check if it has
3060    // local storage within the function, and if so, return the expression.
3061    DeclRefExpr *DR = cast<DeclRefExpr>(E);
3062
3063    if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl()))
3064      if (V->hasLocalStorage()) {
3065        if (!V->getType()->isReferenceType())
3066          return DR;
3067
3068        // Reference variable, follow through to the expression that
3069        // it points to.
3070        if (V->hasInit()) {
3071          // Add the reference variable to the "trail".
3072          refVars.push_back(DR);
3073          return EvalVal(V->getInit(), refVars);
3074        }
3075      }
3076
3077    return NULL;
3078  }
3079
3080  case Stmt::UnaryOperatorClass: {
3081    // The only unary operator that make sense to handle here
3082    // is Deref.  All others don't resolve to a "name."  This includes
3083    // handling all sorts of rvalues passed to a unary operator.
3084    UnaryOperator *U = cast<UnaryOperator>(E);
3085
3086    if (U->getOpcode() == UO_Deref)
3087      return EvalAddr(U->getSubExpr(), refVars);
3088
3089    return NULL;
3090  }
3091
3092  case Stmt::ArraySubscriptExprClass: {
3093    // Array subscripts are potential references to data on the stack.  We
3094    // retrieve the DeclRefExpr* for the array variable if it indeed
3095    // has local storage.
3096    return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars);
3097  }
3098
3099  case Stmt::ConditionalOperatorClass: {
3100    // For conditional operators we need to see if either the LHS or RHS are
3101    // non-NULL Expr's.  If one is non-NULL, we return it.
3102    ConditionalOperator *C = cast<ConditionalOperator>(E);
3103
3104    // Handle the GNU extension for missing LHS.
3105    if (Expr *lhsExpr = C->getLHS())
3106      if (Expr *LHS = EvalVal(lhsExpr, refVars))
3107        return LHS;
3108
3109    return EvalVal(C->getRHS(), refVars);
3110  }
3111
3112  // Accesses to members are potential references to data on the stack.
3113  case Stmt::MemberExprClass: {
3114    MemberExpr *M = cast<MemberExpr>(E);
3115
3116    // Check for indirect access.  We only want direct field accesses.
3117    if (M->isArrow())
3118      return NULL;
3119
3120    // Check whether the member type is itself a reference, in which case
3121    // we're not going to refer to the member, but to what the member refers to.
3122    if (M->getMemberDecl()->getType()->isReferenceType())
3123      return NULL;
3124
3125    return EvalVal(M->getBase(), refVars);
3126  }
3127
3128  case Stmt::MaterializeTemporaryExprClass:
3129    if (Expr *Result = EvalVal(
3130                          cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
3131                               refVars))
3132      return Result;
3133
3134    return E;
3135
3136  default:
3137    // Check that we don't return or take the address of a reference to a
3138    // temporary. This is only useful in C++.
3139    if (!E->isTypeDependent() && E->isRValue())
3140      return E;
3141
3142    // Everything else: we simply don't reason about them.
3143    return NULL;
3144  }
3145} while (true);
3146}
3147
3148//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===//
3149
3150/// Check for comparisons of floating point operands using != and ==.
3151/// Issue a warning if these are no self-comparisons, as they are not likely
3152/// to do what the programmer intended.
3153void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) {
3154  bool EmitWarning = true;
3155
3156  Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts();
3157  Expr* RightExprSansParen = RHS->IgnoreParenImpCasts();
3158
3159  // Special case: check for x == x (which is OK).
3160  // Do not emit warnings for such cases.
3161  if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen))
3162    if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen))
3163      if (DRL->getDecl() == DRR->getDecl())
3164        EmitWarning = false;
3165
3166
3167  // Special case: check for comparisons against literals that can be exactly
3168  //  represented by APFloat.  In such cases, do not emit a warning.  This
3169  //  is a heuristic: often comparison against such literals are used to
3170  //  detect if a value in a variable has not changed.  This clearly can
3171  //  lead to false negatives.
3172  if (EmitWarning) {
3173    if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) {
3174      if (FLL->isExact())
3175        EmitWarning = false;
3176    } else
3177      if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)){
3178        if (FLR->isExact())
3179          EmitWarning = false;
3180    }
3181  }
3182
3183  // Check for comparisons with builtin types.
3184  if (EmitWarning)
3185    if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen))
3186      if (CL->isBuiltinCall())
3187        EmitWarning = false;
3188
3189  if (EmitWarning)
3190    if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen))
3191      if (CR->isBuiltinCall())
3192        EmitWarning = false;
3193
3194  // Emit the diagnostic.
3195  if (EmitWarning)
3196    Diag(Loc, diag::warn_floatingpoint_eq)
3197      << LHS->getSourceRange() << RHS->getSourceRange();
3198}
3199
3200//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===//
3201//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===//
3202
3203namespace {
3204
3205/// Structure recording the 'active' range of an integer-valued
3206/// expression.
3207struct IntRange {
3208  /// The number of bits active in the int.
3209  unsigned Width;
3210
3211  /// True if the int is known not to have negative values.
3212  bool NonNegative;
3213
3214  IntRange(unsigned Width, bool NonNegative)
3215    : Width(Width), NonNegative(NonNegative)
3216  {}
3217
3218  /// Returns the range of the bool type.
3219  static IntRange forBoolType() {
3220    return IntRange(1, true);
3221  }
3222
3223  /// Returns the range of an opaque value of the given integral type.
3224  static IntRange forValueOfType(ASTContext &C, QualType T) {
3225    return forValueOfCanonicalType(C,
3226                          T->getCanonicalTypeInternal().getTypePtr());
3227  }
3228
3229  /// Returns the range of an opaque value of a canonical integral type.
3230  static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) {
3231    assert(T->isCanonicalUnqualified());
3232
3233    if (const VectorType *VT = dyn_cast<VectorType>(T))
3234      T = VT->getElementType().getTypePtr();
3235    if (const ComplexType *CT = dyn_cast<ComplexType>(T))
3236      T = CT->getElementType().getTypePtr();
3237
3238    // For enum types, use the known bit width of the enumerators.
3239    if (const EnumType *ET = dyn_cast<EnumType>(T)) {
3240      EnumDecl *Enum = ET->getDecl();
3241      if (!Enum->isCompleteDefinition())
3242        return IntRange(C.getIntWidth(QualType(T, 0)), false);
3243
3244      unsigned NumPositive = Enum->getNumPositiveBits();
3245      unsigned NumNegative = Enum->getNumNegativeBits();
3246
3247      return IntRange(std::max(NumPositive, NumNegative), NumNegative == 0);
3248    }
3249
3250    const BuiltinType *BT = cast<BuiltinType>(T);
3251    assert(BT->isInteger());
3252
3253    return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
3254  }
3255
3256  /// Returns the "target" range of a canonical integral type, i.e.
3257  /// the range of values expressible in the type.
3258  ///
3259  /// This matches forValueOfCanonicalType except that enums have the
3260  /// full range of their type, not the range of their enumerators.
3261  static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) {
3262    assert(T->isCanonicalUnqualified());
3263
3264    if (const VectorType *VT = dyn_cast<VectorType>(T))
3265      T = VT->getElementType().getTypePtr();
3266    if (const ComplexType *CT = dyn_cast<ComplexType>(T))
3267      T = CT->getElementType().getTypePtr();
3268    if (const EnumType *ET = dyn_cast<EnumType>(T))
3269      T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr();
3270
3271    const BuiltinType *BT = cast<BuiltinType>(T);
3272    assert(BT->isInteger());
3273
3274    return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
3275  }
3276
3277  /// Returns the supremum of two ranges: i.e. their conservative merge.
3278  static IntRange join(IntRange L, IntRange R) {
3279    return IntRange(std::max(L.Width, R.Width),
3280                    L.NonNegative && R.NonNegative);
3281  }
3282
3283  /// Returns the infinum of two ranges: i.e. their aggressive merge.
3284  static IntRange meet(IntRange L, IntRange R) {
3285    return IntRange(std::min(L.Width, R.Width),
3286                    L.NonNegative || R.NonNegative);
3287  }
3288};
3289
3290static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value,
3291                              unsigned MaxWidth) {
3292  if (value.isSigned() && value.isNegative())
3293    return IntRange(value.getMinSignedBits(), false);
3294
3295  if (value.getBitWidth() > MaxWidth)
3296    value = value.trunc(MaxWidth);
3297
3298  // isNonNegative() just checks the sign bit without considering
3299  // signedness.
3300  return IntRange(value.getActiveBits(), true);
3301}
3302
3303static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty,
3304                              unsigned MaxWidth) {
3305  if (result.isInt())
3306    return GetValueRange(C, result.getInt(), MaxWidth);
3307
3308  if (result.isVector()) {
3309    IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth);
3310    for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) {
3311      IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth);
3312      R = IntRange::join(R, El);
3313    }
3314    return R;
3315  }
3316
3317  if (result.isComplexInt()) {
3318    IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth);
3319    IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth);
3320    return IntRange::join(R, I);
3321  }
3322
3323  // This can happen with lossless casts to intptr_t of "based" lvalues.
3324  // Assume it might use arbitrary bits.
3325  // FIXME: The only reason we need to pass the type in here is to get
3326  // the sign right on this one case.  It would be nice if APValue
3327  // preserved this.
3328  assert(result.isLValue() || result.isAddrLabelDiff());
3329  return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType());
3330}
3331
3332/// Pseudo-evaluate the given integer expression, estimating the
3333/// range of values it might take.
3334///
3335/// \param MaxWidth - the width to which the value will be truncated
3336static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) {
3337  E = E->IgnoreParens();
3338
3339  // Try a full evaluation first.
3340  Expr::EvalResult result;
3341  if (E->EvaluateAsRValue(result, C))
3342    return GetValueRange(C, result.Val, E->getType(), MaxWidth);
3343
3344  // I think we only want to look through implicit casts here; if the
3345  // user has an explicit widening cast, we should treat the value as
3346  // being of the new, wider type.
3347  if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) {
3348    if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue)
3349      return GetExprRange(C, CE->getSubExpr(), MaxWidth);
3350
3351    IntRange OutputTypeRange = IntRange::forValueOfType(C, CE->getType());
3352
3353    bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast);
3354
3355    // Assume that non-integer casts can span the full range of the type.
3356    if (!isIntegerCast)
3357      return OutputTypeRange;
3358
3359    IntRange SubRange
3360      = GetExprRange(C, CE->getSubExpr(),
3361                     std::min(MaxWidth, OutputTypeRange.Width));
3362
3363    // Bail out if the subexpr's range is as wide as the cast type.
3364    if (SubRange.Width >= OutputTypeRange.Width)
3365      return OutputTypeRange;
3366
3367    // Otherwise, we take the smaller width, and we're non-negative if
3368    // either the output type or the subexpr is.
3369    return IntRange(SubRange.Width,
3370                    SubRange.NonNegative || OutputTypeRange.NonNegative);
3371  }
3372
3373  if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
3374    // If we can fold the condition, just take that operand.
3375    bool CondResult;
3376    if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C))
3377      return GetExprRange(C, CondResult ? CO->getTrueExpr()
3378                                        : CO->getFalseExpr(),
3379                          MaxWidth);
3380
3381    // Otherwise, conservatively merge.
3382    IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth);
3383    IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth);
3384    return IntRange::join(L, R);
3385  }
3386
3387  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
3388    switch (BO->getOpcode()) {
3389
3390    // Boolean-valued operations are single-bit and positive.
3391    case BO_LAnd:
3392    case BO_LOr:
3393    case BO_LT:
3394    case BO_GT:
3395    case BO_LE:
3396    case BO_GE:
3397    case BO_EQ:
3398    case BO_NE:
3399      return IntRange::forBoolType();
3400
3401    // The type of the assignments is the type of the LHS, so the RHS
3402    // is not necessarily the same type.
3403    case BO_MulAssign:
3404    case BO_DivAssign:
3405    case BO_RemAssign:
3406    case BO_AddAssign:
3407    case BO_SubAssign:
3408    case BO_XorAssign:
3409    case BO_OrAssign:
3410      // TODO: bitfields?
3411      return IntRange::forValueOfType(C, E->getType());
3412
3413    // Simple assignments just pass through the RHS, which will have
3414    // been coerced to the LHS type.
3415    case BO_Assign:
3416      // TODO: bitfields?
3417      return GetExprRange(C, BO->getRHS(), MaxWidth);
3418
3419    // Operations with opaque sources are black-listed.
3420    case BO_PtrMemD:
3421    case BO_PtrMemI:
3422      return IntRange::forValueOfType(C, E->getType());
3423
3424    // Bitwise-and uses the *infinum* of the two source ranges.
3425    case BO_And:
3426    case BO_AndAssign:
3427      return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth),
3428                            GetExprRange(C, BO->getRHS(), MaxWidth));
3429
3430    // Left shift gets black-listed based on a judgement call.
3431    case BO_Shl:
3432      // ...except that we want to treat '1 << (blah)' as logically
3433      // positive.  It's an important idiom.
3434      if (IntegerLiteral *I
3435            = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) {
3436        if (I->getValue() == 1) {
3437          IntRange R = IntRange::forValueOfType(C, E->getType());
3438          return IntRange(R.Width, /*NonNegative*/ true);
3439        }
3440      }
3441      // fallthrough
3442
3443    case BO_ShlAssign:
3444      return IntRange::forValueOfType(C, E->getType());
3445
3446    // Right shift by a constant can narrow its left argument.
3447    case BO_Shr:
3448    case BO_ShrAssign: {
3449      IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
3450
3451      // If the shift amount is a positive constant, drop the width by
3452      // that much.
3453      llvm::APSInt shift;
3454      if (BO->getRHS()->isIntegerConstantExpr(shift, C) &&
3455          shift.isNonNegative()) {
3456        unsigned zext = shift.getZExtValue();
3457        if (zext >= L.Width)
3458          L.Width = (L.NonNegative ? 0 : 1);
3459        else
3460          L.Width -= zext;
3461      }
3462
3463      return L;
3464    }
3465
3466    // Comma acts as its right operand.
3467    case BO_Comma:
3468      return GetExprRange(C, BO->getRHS(), MaxWidth);
3469
3470    // Black-list pointer subtractions.
3471    case BO_Sub:
3472      if (BO->getLHS()->getType()->isPointerType())
3473        return IntRange::forValueOfType(C, E->getType());
3474      break;
3475
3476    // The width of a division result is mostly determined by the size
3477    // of the LHS.
3478    case BO_Div: {
3479      // Don't 'pre-truncate' the operands.
3480      unsigned opWidth = C.getIntWidth(E->getType());
3481      IntRange L = GetExprRange(C, BO->getLHS(), opWidth);
3482
3483      // If the divisor is constant, use that.
3484      llvm::APSInt divisor;
3485      if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) {
3486        unsigned log2 = divisor.logBase2(); // floor(log_2(divisor))
3487        if (log2 >= L.Width)
3488          L.Width = (L.NonNegative ? 0 : 1);
3489        else
3490          L.Width = std::min(L.Width - log2, MaxWidth);
3491        return L;
3492      }
3493
3494      // Otherwise, just use the LHS's width.
3495      IntRange R = GetExprRange(C, BO->getRHS(), opWidth);
3496      return IntRange(L.Width, L.NonNegative && R.NonNegative);
3497    }
3498
3499    // The result of a remainder can't be larger than the result of
3500    // either side.
3501    case BO_Rem: {
3502      // Don't 'pre-truncate' the operands.
3503      unsigned opWidth = C.getIntWidth(E->getType());
3504      IntRange L = GetExprRange(C, BO->getLHS(), opWidth);
3505      IntRange R = GetExprRange(C, BO->getRHS(), opWidth);
3506
3507      IntRange meet = IntRange::meet(L, R);
3508      meet.Width = std::min(meet.Width, MaxWidth);
3509      return meet;
3510    }
3511
3512    // The default behavior is okay for these.
3513    case BO_Mul:
3514    case BO_Add:
3515    case BO_Xor:
3516    case BO_Or:
3517      break;
3518    }
3519
3520    // The default case is to treat the operation as if it were closed
3521    // on the narrowest type that encompasses both operands.
3522    IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
3523    IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth);
3524    return IntRange::join(L, R);
3525  }
3526
3527  if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
3528    switch (UO->getOpcode()) {
3529    // Boolean-valued operations are white-listed.
3530    case UO_LNot:
3531      return IntRange::forBoolType();
3532
3533    // Operations with opaque sources are black-listed.
3534    case UO_Deref:
3535    case UO_AddrOf: // should be impossible
3536      return IntRange::forValueOfType(C, E->getType());
3537
3538    default:
3539      return GetExprRange(C, UO->getSubExpr(), MaxWidth);
3540    }
3541  }
3542
3543  if (dyn_cast<OffsetOfExpr>(E)) {
3544    IntRange::forValueOfType(C, E->getType());
3545  }
3546
3547  if (FieldDecl *BitField = E->getBitField())
3548    return IntRange(BitField->getBitWidthValue(C),
3549                    BitField->getType()->isUnsignedIntegerOrEnumerationType());
3550
3551  return IntRange::forValueOfType(C, E->getType());
3552}
3553
3554static IntRange GetExprRange(ASTContext &C, Expr *E) {
3555  return GetExprRange(C, E, C.getIntWidth(E->getType()));
3556}
3557
3558/// Checks whether the given value, which currently has the given
3559/// source semantics, has the same value when coerced through the
3560/// target semantics.
3561static bool IsSameFloatAfterCast(const llvm::APFloat &value,
3562                                 const llvm::fltSemantics &Src,
3563                                 const llvm::fltSemantics &Tgt) {
3564  llvm::APFloat truncated = value;
3565
3566  bool ignored;
3567  truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored);
3568  truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored);
3569
3570  return truncated.bitwiseIsEqual(value);
3571}
3572
3573/// Checks whether the given value, which currently has the given
3574/// source semantics, has the same value when coerced through the
3575/// target semantics.
3576///
3577/// The value might be a vector of floats (or a complex number).
3578static bool IsSameFloatAfterCast(const APValue &value,
3579                                 const llvm::fltSemantics &Src,
3580                                 const llvm::fltSemantics &Tgt) {
3581  if (value.isFloat())
3582    return IsSameFloatAfterCast(value.getFloat(), Src, Tgt);
3583
3584  if (value.isVector()) {
3585    for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i)
3586      if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt))
3587        return false;
3588    return true;
3589  }
3590
3591  assert(value.isComplexFloat());
3592  return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) &&
3593          IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt));
3594}
3595
3596static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC);
3597
3598static bool IsZero(Sema &S, Expr *E) {
3599  // Suppress cases where we are comparing against an enum constant.
3600  if (const DeclRefExpr *DR =
3601      dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
3602    if (isa<EnumConstantDecl>(DR->getDecl()))
3603      return false;
3604
3605  // Suppress cases where the '0' value is expanded from a macro.
3606  if (E->getLocStart().isMacroID())
3607    return false;
3608
3609  llvm::APSInt Value;
3610  return E->isIntegerConstantExpr(Value, S.Context) && Value == 0;
3611}
3612
3613static bool HasEnumType(Expr *E) {
3614  // Strip off implicit integral promotions.
3615  while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
3616    if (ICE->getCastKind() != CK_IntegralCast &&
3617        ICE->getCastKind() != CK_NoOp)
3618      break;
3619    E = ICE->getSubExpr();
3620  }
3621
3622  return E->getType()->isEnumeralType();
3623}
3624
3625static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) {
3626  BinaryOperatorKind op = E->getOpcode();
3627  if (E->isValueDependent())
3628    return;
3629
3630  if (op == BO_LT && IsZero(S, E->getRHS())) {
3631    S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
3632      << "< 0" << "false" << HasEnumType(E->getLHS())
3633      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
3634  } else if (op == BO_GE && IsZero(S, E->getRHS())) {
3635    S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
3636      << ">= 0" << "true" << HasEnumType(E->getLHS())
3637      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
3638  } else if (op == BO_GT && IsZero(S, E->getLHS())) {
3639    S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
3640      << "0 >" << "false" << HasEnumType(E->getRHS())
3641      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
3642  } else if (op == BO_LE && IsZero(S, E->getLHS())) {
3643    S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
3644      << "0 <=" << "true" << HasEnumType(E->getRHS())
3645      << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
3646  }
3647}
3648
3649/// Analyze the operands of the given comparison.  Implements the
3650/// fallback case from AnalyzeComparison.
3651static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) {
3652  AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
3653  AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
3654}
3655
3656/// \brief Implements -Wsign-compare.
3657///
3658/// \param E the binary operator to check for warnings
3659static void AnalyzeComparison(Sema &S, BinaryOperator *E) {
3660  // The type the comparison is being performed in.
3661  QualType T = E->getLHS()->getType();
3662  assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType())
3663         && "comparison with mismatched types");
3664
3665  // We don't do anything special if this isn't an unsigned integral
3666  // comparison:  we're only interested in integral comparisons, and
3667  // signed comparisons only happen in cases we don't care to warn about.
3668  //
3669  // We also don't care about value-dependent expressions or expressions
3670  // whose result is a constant.
3671  if (!T->hasUnsignedIntegerRepresentation()
3672      || E->isValueDependent() || E->isIntegerConstantExpr(S.Context))
3673    return AnalyzeImpConvsInComparison(S, E);
3674
3675  Expr *LHS = E->getLHS()->IgnoreParenImpCasts();
3676  Expr *RHS = E->getRHS()->IgnoreParenImpCasts();
3677
3678  // Check to see if one of the (unmodified) operands is of different
3679  // signedness.
3680  Expr *signedOperand, *unsignedOperand;
3681  if (LHS->getType()->hasSignedIntegerRepresentation()) {
3682    assert(!RHS->getType()->hasSignedIntegerRepresentation() &&
3683           "unsigned comparison between two signed integer expressions?");
3684    signedOperand = LHS;
3685    unsignedOperand = RHS;
3686  } else if (RHS->getType()->hasSignedIntegerRepresentation()) {
3687    signedOperand = RHS;
3688    unsignedOperand = LHS;
3689  } else {
3690    CheckTrivialUnsignedComparison(S, E);
3691    return AnalyzeImpConvsInComparison(S, E);
3692  }
3693
3694  // Otherwise, calculate the effective range of the signed operand.
3695  IntRange signedRange = GetExprRange(S.Context, signedOperand);
3696
3697  // Go ahead and analyze implicit conversions in the operands.  Note
3698  // that we skip the implicit conversions on both sides.
3699  AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc());
3700  AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc());
3701
3702  // If the signed range is non-negative, -Wsign-compare won't fire,
3703  // but we should still check for comparisons which are always true
3704  // or false.
3705  if (signedRange.NonNegative)
3706    return CheckTrivialUnsignedComparison(S, E);
3707
3708  // For (in)equality comparisons, if the unsigned operand is a
3709  // constant which cannot collide with a overflowed signed operand,
3710  // then reinterpreting the signed operand as unsigned will not
3711  // change the result of the comparison.
3712  if (E->isEqualityOp()) {
3713    unsigned comparisonWidth = S.Context.getIntWidth(T);
3714    IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand);
3715
3716    // We should never be unable to prove that the unsigned operand is
3717    // non-negative.
3718    assert(unsignedRange.NonNegative && "unsigned range includes negative?");
3719
3720    if (unsignedRange.Width < comparisonWidth)
3721      return;
3722  }
3723
3724  S.Diag(E->getOperatorLoc(), diag::warn_mixed_sign_comparison)
3725    << LHS->getType() << RHS->getType()
3726    << LHS->getSourceRange() << RHS->getSourceRange();
3727}
3728
3729/// Analyzes an attempt to assign the given value to a bitfield.
3730///
3731/// Returns true if there was something fishy about the attempt.
3732static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init,
3733                                      SourceLocation InitLoc) {
3734  assert(Bitfield->isBitField());
3735  if (Bitfield->isInvalidDecl())
3736    return false;
3737
3738  // White-list bool bitfields.
3739  if (Bitfield->getType()->isBooleanType())
3740    return false;
3741
3742  // Ignore value- or type-dependent expressions.
3743  if (Bitfield->getBitWidth()->isValueDependent() ||
3744      Bitfield->getBitWidth()->isTypeDependent() ||
3745      Init->isValueDependent() ||
3746      Init->isTypeDependent())
3747    return false;
3748
3749  Expr *OriginalInit = Init->IgnoreParenImpCasts();
3750
3751  llvm::APSInt Value;
3752  if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects))
3753    return false;
3754
3755  unsigned OriginalWidth = Value.getBitWidth();
3756  unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context);
3757
3758  if (OriginalWidth <= FieldWidth)
3759    return false;
3760
3761  // Compute the value which the bitfield will contain.
3762  llvm::APSInt TruncatedValue = Value.trunc(FieldWidth);
3763  TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType());
3764
3765  // Check whether the stored value is equal to the original value.
3766  TruncatedValue = TruncatedValue.extend(OriginalWidth);
3767  if (Value == TruncatedValue)
3768    return false;
3769
3770  // Special-case bitfields of width 1: booleans are naturally 0/1, and
3771  // therefore don't strictly fit into a signed bitfield of width 1.
3772  if (FieldWidth == 1 && Value == 1)
3773    return false;
3774
3775  std::string PrettyValue = Value.toString(10);
3776  std::string PrettyTrunc = TruncatedValue.toString(10);
3777
3778  S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant)
3779    << PrettyValue << PrettyTrunc << OriginalInit->getType()
3780    << Init->getSourceRange();
3781
3782  return true;
3783}
3784
3785/// Analyze the given simple or compound assignment for warning-worthy
3786/// operations.
3787static void AnalyzeAssignment(Sema &S, BinaryOperator *E) {
3788  // Just recurse on the LHS.
3789  AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
3790
3791  // We want to recurse on the RHS as normal unless we're assigning to
3792  // a bitfield.
3793  if (FieldDecl *Bitfield = E->getLHS()->getBitField()) {
3794    if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(),
3795                                  E->getOperatorLoc())) {
3796      // Recurse, ignoring any implicit conversions on the RHS.
3797      return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(),
3798                                        E->getOperatorLoc());
3799    }
3800  }
3801
3802  AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
3803}
3804
3805/// Diagnose an implicit cast;  purely a helper for CheckImplicitConversion.
3806static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T,
3807                            SourceLocation CContext, unsigned diag,
3808                            bool pruneControlFlow = false) {
3809  if (pruneControlFlow) {
3810    S.DiagRuntimeBehavior(E->getExprLoc(), E,
3811                          S.PDiag(diag)
3812                            << SourceType << T << E->getSourceRange()
3813                            << SourceRange(CContext));
3814    return;
3815  }
3816  S.Diag(E->getExprLoc(), diag)
3817    << SourceType << T << E->getSourceRange() << SourceRange(CContext);
3818}
3819
3820/// Diagnose an implicit cast;  purely a helper for CheckImplicitConversion.
3821static void DiagnoseImpCast(Sema &S, Expr *E, QualType T,
3822                            SourceLocation CContext, unsigned diag,
3823                            bool pruneControlFlow = false) {
3824  DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow);
3825}
3826
3827/// Diagnose an implicit cast from a literal expression. Does not warn when the
3828/// cast wouldn't lose information.
3829void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T,
3830                                    SourceLocation CContext) {
3831  // Try to convert the literal exactly to an integer. If we can, don't warn.
3832  bool isExact = false;
3833  const llvm::APFloat &Value = FL->getValue();
3834  llvm::APSInt IntegerValue(S.Context.getIntWidth(T),
3835                            T->hasUnsignedIntegerRepresentation());
3836  if (Value.convertToInteger(IntegerValue,
3837                             llvm::APFloat::rmTowardZero, &isExact)
3838      == llvm::APFloat::opOK && isExact)
3839    return;
3840
3841  S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer)
3842    << FL->getType() << T << FL->getSourceRange() << SourceRange(CContext);
3843}
3844
3845std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) {
3846  if (!Range.Width) return "0";
3847
3848  llvm::APSInt ValueInRange = Value;
3849  ValueInRange.setIsSigned(!Range.NonNegative);
3850  ValueInRange = ValueInRange.trunc(Range.Width);
3851  return ValueInRange.toString(10);
3852}
3853
3854void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
3855                             SourceLocation CC, bool *ICContext = 0) {
3856  if (E->isTypeDependent() || E->isValueDependent()) return;
3857
3858  const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr();
3859  const Type *Target = S.Context.getCanonicalType(T).getTypePtr();
3860  if (Source == Target) return;
3861  if (Target->isDependentType()) return;
3862
3863  // If the conversion context location is invalid don't complain. We also
3864  // don't want to emit a warning if the issue occurs from the expansion of
3865  // a system macro. The problem is that 'getSpellingLoc()' is slow, so we
3866  // delay this check as long as possible. Once we detect we are in that
3867  // scenario, we just return.
3868  if (CC.isInvalid())
3869    return;
3870
3871  // Diagnose implicit casts to bool.
3872  if (Target->isSpecificBuiltinType(BuiltinType::Bool)) {
3873    if (isa<StringLiteral>(E))
3874      // Warn on string literal to bool.  Checks for string literals in logical
3875      // expressions, for instances, assert(0 && "error here"), is prevented
3876      // by a check in AnalyzeImplicitConversions().
3877      return DiagnoseImpCast(S, E, T, CC,
3878                             diag::warn_impcast_string_literal_to_bool);
3879    if (Source->isFunctionType()) {
3880      // Warn on function to bool. Checks free functions and static member
3881      // functions. Weakly imported functions are excluded from the check,
3882      // since it's common to test their value to check whether the linker
3883      // found a definition for them.
3884      ValueDecl *D = 0;
3885      if (DeclRefExpr* R = dyn_cast<DeclRefExpr>(E)) {
3886        D = R->getDecl();
3887      } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) {
3888        D = M->getMemberDecl();
3889      }
3890
3891      if (D && !D->isWeak()) {
3892        if (FunctionDecl* F = dyn_cast<FunctionDecl>(D)) {
3893          S.Diag(E->getExprLoc(), diag::warn_impcast_function_to_bool)
3894            << F << E->getSourceRange() << SourceRange(CC);
3895          S.Diag(E->getExprLoc(), diag::note_function_to_bool_silence)
3896            << FixItHint::CreateInsertion(E->getExprLoc(), "&");
3897          QualType ReturnType;
3898          UnresolvedSet<4> NonTemplateOverloads;
3899          S.isExprCallable(*E, ReturnType, NonTemplateOverloads);
3900          if (!ReturnType.isNull()
3901              && ReturnType->isSpecificBuiltinType(BuiltinType::Bool))
3902            S.Diag(E->getExprLoc(), diag::note_function_to_bool_call)
3903              << FixItHint::CreateInsertion(
3904                 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()), "()");
3905          return;
3906        }
3907      }
3908    }
3909    return; // Other casts to bool are not checked.
3910  }
3911
3912  // Strip vector types.
3913  if (isa<VectorType>(Source)) {
3914    if (!isa<VectorType>(Target)) {
3915      if (S.SourceMgr.isInSystemMacro(CC))
3916        return;
3917      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar);
3918    }
3919
3920    // If the vector cast is cast between two vectors of the same size, it is
3921    // a bitcast, not a conversion.
3922    if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target))
3923      return;
3924
3925    Source = cast<VectorType>(Source)->getElementType().getTypePtr();
3926    Target = cast<VectorType>(Target)->getElementType().getTypePtr();
3927  }
3928
3929  // Strip complex types.
3930  if (isa<ComplexType>(Source)) {
3931    if (!isa<ComplexType>(Target)) {
3932      if (S.SourceMgr.isInSystemMacro(CC))
3933        return;
3934
3935      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar);
3936    }
3937
3938    Source = cast<ComplexType>(Source)->getElementType().getTypePtr();
3939    Target = cast<ComplexType>(Target)->getElementType().getTypePtr();
3940  }
3941
3942  const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source);
3943  const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target);
3944
3945  // If the source is floating point...
3946  if (SourceBT && SourceBT->isFloatingPoint()) {
3947    // ...and the target is floating point...
3948    if (TargetBT && TargetBT->isFloatingPoint()) {
3949      // ...then warn if we're dropping FP rank.
3950
3951      // Builtin FP kinds are ordered by increasing FP rank.
3952      if (SourceBT->getKind() > TargetBT->getKind()) {
3953        // Don't warn about float constants that are precisely
3954        // representable in the target type.
3955        Expr::EvalResult result;
3956        if (E->EvaluateAsRValue(result, S.Context)) {
3957          // Value might be a float, a float vector, or a float complex.
3958          if (IsSameFloatAfterCast(result.Val,
3959                   S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)),
3960                   S.Context.getFloatTypeSemantics(QualType(SourceBT, 0))))
3961            return;
3962        }
3963
3964        if (S.SourceMgr.isInSystemMacro(CC))
3965          return;
3966
3967        DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision);
3968      }
3969      return;
3970    }
3971
3972    // If the target is integral, always warn.
3973    if ((TargetBT && TargetBT->isInteger())) {
3974      if (S.SourceMgr.isInSystemMacro(CC))
3975        return;
3976
3977      Expr *InnerE = E->IgnoreParenImpCasts();
3978      // We also want to warn on, e.g., "int i = -1.234"
3979      if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE))
3980        if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus)
3981          InnerE = UOp->getSubExpr()->IgnoreParenImpCasts();
3982
3983      if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) {
3984        DiagnoseFloatingLiteralImpCast(S, FL, T, CC);
3985      } else {
3986        DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer);
3987      }
3988    }
3989
3990    return;
3991  }
3992
3993  if (!Source->isIntegerType() || !Target->isIntegerType())
3994    return;
3995
3996  if ((E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull)
3997           == Expr::NPCK_GNUNull) && Target->isIntegerType()) {
3998    S.Diag(E->getExprLoc(), diag::warn_impcast_null_pointer_to_integer)
3999        << E->getSourceRange() << clang::SourceRange(CC);
4000    return;
4001  }
4002
4003  IntRange SourceRange = GetExprRange(S.Context, E);
4004  IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target);
4005
4006  if (SourceRange.Width > TargetRange.Width) {
4007    // If the source is a constant, use a default-on diagnostic.
4008    // TODO: this should happen for bitfield stores, too.
4009    llvm::APSInt Value(32);
4010    if (E->isIntegerConstantExpr(Value, S.Context)) {
4011      if (S.SourceMgr.isInSystemMacro(CC))
4012        return;
4013
4014      std::string PrettySourceValue = Value.toString(10);
4015      std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange);
4016
4017      S.DiagRuntimeBehavior(E->getExprLoc(), E,
4018        S.PDiag(diag::warn_impcast_integer_precision_constant)
4019            << PrettySourceValue << PrettyTargetValue
4020            << E->getType() << T << E->getSourceRange()
4021            << clang::SourceRange(CC));
4022      return;
4023    }
4024
4025    // People want to build with -Wshorten-64-to-32 and not -Wconversion.
4026    if (S.SourceMgr.isInSystemMacro(CC))
4027      return;
4028
4029    if (SourceRange.Width == 64 && TargetRange.Width == 32)
4030      return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32,
4031                             /* pruneControlFlow */ true);
4032    return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision);
4033  }
4034
4035  if ((TargetRange.NonNegative && !SourceRange.NonNegative) ||
4036      (!TargetRange.NonNegative && SourceRange.NonNegative &&
4037       SourceRange.Width == TargetRange.Width)) {
4038
4039    if (S.SourceMgr.isInSystemMacro(CC))
4040      return;
4041
4042    unsigned DiagID = diag::warn_impcast_integer_sign;
4043
4044    // Traditionally, gcc has warned about this under -Wsign-compare.
4045    // We also want to warn about it in -Wconversion.
4046    // So if -Wconversion is off, use a completely identical diagnostic
4047    // in the sign-compare group.
4048    // The conditional-checking code will
4049    if (ICContext) {
4050      DiagID = diag::warn_impcast_integer_sign_conditional;
4051      *ICContext = true;
4052    }
4053
4054    return DiagnoseImpCast(S, E, T, CC, DiagID);
4055  }
4056
4057  // Diagnose conversions between different enumeration types.
4058  // In C, we pretend that the type of an EnumConstantDecl is its enumeration
4059  // type, to give us better diagnostics.
4060  QualType SourceType = E->getType();
4061  if (!S.getLangOptions().CPlusPlus) {
4062    if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
4063      if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) {
4064        EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext());
4065        SourceType = S.Context.getTypeDeclType(Enum);
4066        Source = S.Context.getCanonicalType(SourceType).getTypePtr();
4067      }
4068  }
4069
4070  if (const EnumType *SourceEnum = Source->getAs<EnumType>())
4071    if (const EnumType *TargetEnum = Target->getAs<EnumType>())
4072      if ((SourceEnum->getDecl()->getIdentifier() ||
4073           SourceEnum->getDecl()->getTypedefNameForAnonDecl()) &&
4074          (TargetEnum->getDecl()->getIdentifier() ||
4075           TargetEnum->getDecl()->getTypedefNameForAnonDecl()) &&
4076          SourceEnum != TargetEnum) {
4077        if (S.SourceMgr.isInSystemMacro(CC))
4078          return;
4079
4080        return DiagnoseImpCast(S, E, SourceType, T, CC,
4081                               diag::warn_impcast_different_enum_types);
4082      }
4083
4084  return;
4085}
4086
4087void CheckConditionalOperator(Sema &S, ConditionalOperator *E, QualType T);
4088
4089void CheckConditionalOperand(Sema &S, Expr *E, QualType T,
4090                             SourceLocation CC, bool &ICContext) {
4091  E = E->IgnoreParenImpCasts();
4092
4093  if (isa<ConditionalOperator>(E))
4094    return CheckConditionalOperator(S, cast<ConditionalOperator>(E), T);
4095
4096  AnalyzeImplicitConversions(S, E, CC);
4097  if (E->getType() != T)
4098    return CheckImplicitConversion(S, E, T, CC, &ICContext);
4099  return;
4100}
4101
4102void CheckConditionalOperator(Sema &S, ConditionalOperator *E, QualType T) {
4103  SourceLocation CC = E->getQuestionLoc();
4104
4105  AnalyzeImplicitConversions(S, E->getCond(), CC);
4106
4107  bool Suspicious = false;
4108  CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious);
4109  CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious);
4110
4111  // If -Wconversion would have warned about either of the candidates
4112  // for a signedness conversion to the context type...
4113  if (!Suspicious) return;
4114
4115  // ...but it's currently ignored...
4116  if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional,
4117                                 CC))
4118    return;
4119
4120  // ...then check whether it would have warned about either of the
4121  // candidates for a signedness conversion to the condition type.
4122  if (E->getType() == T) return;
4123
4124  Suspicious = false;
4125  CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(),
4126                          E->getType(), CC, &Suspicious);
4127  if (!Suspicious)
4128    CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(),
4129                            E->getType(), CC, &Suspicious);
4130}
4131
4132/// AnalyzeImplicitConversions - Find and report any interesting
4133/// implicit conversions in the given expression.  There are a couple
4134/// of competing diagnostics here, -Wconversion and -Wsign-compare.
4135void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) {
4136  QualType T = OrigE->getType();
4137  Expr *E = OrigE->IgnoreParenImpCasts();
4138
4139  if (E->isTypeDependent() || E->isValueDependent())
4140    return;
4141
4142  // For conditional operators, we analyze the arguments as if they
4143  // were being fed directly into the output.
4144  if (isa<ConditionalOperator>(E)) {
4145    ConditionalOperator *CO = cast<ConditionalOperator>(E);
4146    CheckConditionalOperator(S, CO, T);
4147    return;
4148  }
4149
4150  // Go ahead and check any implicit conversions we might have skipped.
4151  // The non-canonical typecheck is just an optimization;
4152  // CheckImplicitConversion will filter out dead implicit conversions.
4153  if (E->getType() != T)
4154    CheckImplicitConversion(S, E, T, CC);
4155
4156  // Now continue drilling into this expression.
4157
4158  // Skip past explicit casts.
4159  if (isa<ExplicitCastExpr>(E)) {
4160    E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts();
4161    return AnalyzeImplicitConversions(S, E, CC);
4162  }
4163
4164  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
4165    // Do a somewhat different check with comparison operators.
4166    if (BO->isComparisonOp())
4167      return AnalyzeComparison(S, BO);
4168
4169    // And with simple assignments.
4170    if (BO->getOpcode() == BO_Assign)
4171      return AnalyzeAssignment(S, BO);
4172  }
4173
4174  // These break the otherwise-useful invariant below.  Fortunately,
4175  // we don't really need to recurse into them, because any internal
4176  // expressions should have been analyzed already when they were
4177  // built into statements.
4178  if (isa<StmtExpr>(E)) return;
4179
4180  // Don't descend into unevaluated contexts.
4181  if (isa<UnaryExprOrTypeTraitExpr>(E)) return;
4182
4183  // Now just recurse over the expression's children.
4184  CC = E->getExprLoc();
4185  BinaryOperator *BO = dyn_cast<BinaryOperator>(E);
4186  bool IsLogicalOperator = BO && BO->isLogicalOp();
4187  for (Stmt::child_range I = E->children(); I; ++I) {
4188    Expr *ChildExpr = dyn_cast_or_null<Expr>(*I);
4189    if (!ChildExpr)
4190      continue;
4191
4192    if (IsLogicalOperator &&
4193        isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts()))
4194      // Ignore checking string literals that are in logical operators.
4195      continue;
4196    AnalyzeImplicitConversions(S, ChildExpr, CC);
4197  }
4198}
4199
4200} // end anonymous namespace
4201
4202/// Diagnoses "dangerous" implicit conversions within the given
4203/// expression (which is a full expression).  Implements -Wconversion
4204/// and -Wsign-compare.
4205///
4206/// \param CC the "context" location of the implicit conversion, i.e.
4207///   the most location of the syntactic entity requiring the implicit
4208///   conversion
4209void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) {
4210  // Don't diagnose in unevaluated contexts.
4211  if (ExprEvalContexts.back().Context == Sema::Unevaluated)
4212    return;
4213
4214  // Don't diagnose for value- or type-dependent expressions.
4215  if (E->isTypeDependent() || E->isValueDependent())
4216    return;
4217
4218  // Check for array bounds violations in cases where the check isn't triggered
4219  // elsewhere for other Expr types (like BinaryOperators), e.g. when an
4220  // ArraySubscriptExpr is on the RHS of a variable initialization.
4221  CheckArrayAccess(E);
4222
4223  // This is not the right CC for (e.g.) a variable initialization.
4224  AnalyzeImplicitConversions(*this, E, CC);
4225}
4226
4227void Sema::CheckBitFieldInitialization(SourceLocation InitLoc,
4228                                       FieldDecl *BitField,
4229                                       Expr *Init) {
4230  (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc);
4231}
4232
4233/// CheckParmsForFunctionDef - Check that the parameters of the given
4234/// function are appropriate for the definition of a function. This
4235/// takes care of any checks that cannot be performed on the
4236/// declaration itself, e.g., that the types of each of the function
4237/// parameters are complete.
4238bool Sema::CheckParmsForFunctionDef(ParmVarDecl **P, ParmVarDecl **PEnd,
4239                                    bool CheckParameterNames) {
4240  bool HasInvalidParm = false;
4241  for (; P != PEnd; ++P) {
4242    ParmVarDecl *Param = *P;
4243
4244    // C99 6.7.5.3p4: the parameters in a parameter type list in a
4245    // function declarator that is part of a function definition of
4246    // that function shall not have incomplete type.
4247    //
4248    // This is also C++ [dcl.fct]p6.
4249    if (!Param->isInvalidDecl() &&
4250        RequireCompleteType(Param->getLocation(), Param->getType(),
4251                               diag::err_typecheck_decl_incomplete_type)) {
4252      Param->setInvalidDecl();
4253      HasInvalidParm = true;
4254    }
4255
4256    // C99 6.9.1p5: If the declarator includes a parameter type list, the
4257    // declaration of each parameter shall include an identifier.
4258    if (CheckParameterNames &&
4259        Param->getIdentifier() == 0 &&
4260        !Param->isImplicit() &&
4261        !getLangOptions().CPlusPlus)
4262      Diag(Param->getLocation(), diag::err_parameter_name_omitted);
4263
4264    // C99 6.7.5.3p12:
4265    //   If the function declarator is not part of a definition of that
4266    //   function, parameters may have incomplete type and may use the [*]
4267    //   notation in their sequences of declarator specifiers to specify
4268    //   variable length array types.
4269    QualType PType = Param->getOriginalType();
4270    if (const ArrayType *AT = Context.getAsArrayType(PType)) {
4271      if (AT->getSizeModifier() == ArrayType::Star) {
4272        // FIXME: This diagnosic should point the the '[*]' if source-location
4273        // information is added for it.
4274        Diag(Param->getLocation(), diag::err_array_star_in_function_definition);
4275      }
4276    }
4277  }
4278
4279  return HasInvalidParm;
4280}
4281
4282/// CheckCastAlign - Implements -Wcast-align, which warns when a
4283/// pointer cast increases the alignment requirements.
4284void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) {
4285  // This is actually a lot of work to potentially be doing on every
4286  // cast; don't do it if we're ignoring -Wcast_align (as is the default).
4287  if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align,
4288                                          TRange.getBegin())
4289        == DiagnosticsEngine::Ignored)
4290    return;
4291
4292  // Ignore dependent types.
4293  if (T->isDependentType() || Op->getType()->isDependentType())
4294    return;
4295
4296  // Require that the destination be a pointer type.
4297  const PointerType *DestPtr = T->getAs<PointerType>();
4298  if (!DestPtr) return;
4299
4300  // If the destination has alignment 1, we're done.
4301  QualType DestPointee = DestPtr->getPointeeType();
4302  if (DestPointee->isIncompleteType()) return;
4303  CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee);
4304  if (DestAlign.isOne()) return;
4305
4306  // Require that the source be a pointer type.
4307  const PointerType *SrcPtr = Op->getType()->getAs<PointerType>();
4308  if (!SrcPtr) return;
4309  QualType SrcPointee = SrcPtr->getPointeeType();
4310
4311  // Whitelist casts from cv void*.  We already implicitly
4312  // whitelisted casts to cv void*, since they have alignment 1.
4313  // Also whitelist casts involving incomplete types, which implicitly
4314  // includes 'void'.
4315  if (SrcPointee->isIncompleteType()) return;
4316
4317  CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee);
4318  if (SrcAlign >= DestAlign) return;
4319
4320  Diag(TRange.getBegin(), diag::warn_cast_align)
4321    << Op->getType() << T
4322    << static_cast<unsigned>(SrcAlign.getQuantity())
4323    << static_cast<unsigned>(DestAlign.getQuantity())
4324    << TRange << Op->getSourceRange();
4325}
4326
4327static const Type* getElementType(const Expr *BaseExpr) {
4328  const Type* EltType = BaseExpr->getType().getTypePtr();
4329  if (EltType->isAnyPointerType())
4330    return EltType->getPointeeType().getTypePtr();
4331  else if (EltType->isArrayType())
4332    return EltType->getBaseElementTypeUnsafe();
4333  return EltType;
4334}
4335
4336/// \brief Check whether this array fits the idiom of a size-one tail padded
4337/// array member of a struct.
4338///
4339/// We avoid emitting out-of-bounds access warnings for such arrays as they are
4340/// commonly used to emulate flexible arrays in C89 code.
4341static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size,
4342                                    const NamedDecl *ND) {
4343  if (Size != 1 || !ND) return false;
4344
4345  const FieldDecl *FD = dyn_cast<FieldDecl>(ND);
4346  if (!FD) return false;
4347
4348  // Don't consider sizes resulting from macro expansions or template argument
4349  // substitution to form C89 tail-padded arrays.
4350  ConstantArrayTypeLoc TL =
4351    cast<ConstantArrayTypeLoc>(FD->getTypeSourceInfo()->getTypeLoc());
4352  const Expr *SizeExpr = dyn_cast<IntegerLiteral>(TL.getSizeExpr());
4353  if (!SizeExpr || SizeExpr->getExprLoc().isMacroID())
4354    return false;
4355
4356  const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext());
4357  if (!RD) return false;
4358  if (RD->isUnion()) return false;
4359  if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
4360    if (!CRD->isStandardLayout()) return false;
4361  }
4362
4363  // See if this is the last field decl in the record.
4364  const Decl *D = FD;
4365  while ((D = D->getNextDeclInContext()))
4366    if (isa<FieldDecl>(D))
4367      return false;
4368  return true;
4369}
4370
4371void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr,
4372                            const ArraySubscriptExpr *ASE,
4373                            bool AllowOnePastEnd, bool IndexNegated) {
4374  IndexExpr = IndexExpr->IgnoreParenCasts();
4375  if (IndexExpr->isValueDependent())
4376    return;
4377
4378  const Type *EffectiveType = getElementType(BaseExpr);
4379  BaseExpr = BaseExpr->IgnoreParenCasts();
4380  const ConstantArrayType *ArrayTy =
4381    Context.getAsConstantArrayType(BaseExpr->getType());
4382  if (!ArrayTy)
4383    return;
4384
4385  llvm::APSInt index;
4386  if (!IndexExpr->EvaluateAsInt(index, Context))
4387    return;
4388  if (IndexNegated)
4389    index = -index;
4390
4391  const NamedDecl *ND = NULL;
4392  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))
4393    ND = dyn_cast<NamedDecl>(DRE->getDecl());
4394  if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr))
4395    ND = dyn_cast<NamedDecl>(ME->getMemberDecl());
4396
4397  if (index.isUnsigned() || !index.isNegative()) {
4398    llvm::APInt size = ArrayTy->getSize();
4399    if (!size.isStrictlyPositive())
4400      return;
4401
4402    const Type* BaseType = getElementType(BaseExpr);
4403    if (BaseType != EffectiveType) {
4404      // Make sure we're comparing apples to apples when comparing index to size
4405      uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType);
4406      uint64_t array_typesize = Context.getTypeSize(BaseType);
4407      // Handle ptrarith_typesize being zero, such as when casting to void*
4408      if (!ptrarith_typesize) ptrarith_typesize = 1;
4409      if (ptrarith_typesize != array_typesize) {
4410        // There's a cast to a different size type involved
4411        uint64_t ratio = array_typesize / ptrarith_typesize;
4412        // TODO: Be smarter about handling cases where array_typesize is not a
4413        // multiple of ptrarith_typesize
4414        if (ptrarith_typesize * ratio == array_typesize)
4415          size *= llvm::APInt(size.getBitWidth(), ratio);
4416      }
4417    }
4418
4419    if (size.getBitWidth() > index.getBitWidth())
4420      index = index.sext(size.getBitWidth());
4421    else if (size.getBitWidth() < index.getBitWidth())
4422      size = size.sext(index.getBitWidth());
4423
4424    // For array subscripting the index must be less than size, but for pointer
4425    // arithmetic also allow the index (offset) to be equal to size since
4426    // computing the next address after the end of the array is legal and
4427    // commonly done e.g. in C++ iterators and range-based for loops.
4428    if (AllowOnePastEnd ? index.sle(size) : index.slt(size))
4429      return;
4430
4431    // Also don't warn for arrays of size 1 which are members of some
4432    // structure. These are often used to approximate flexible arrays in C89
4433    // code.
4434    if (IsTailPaddedMemberArray(*this, size, ND))
4435      return;
4436
4437    // Suppress the warning if the subscript expression (as identified by the
4438    // ']' location) and the index expression are both from macro expansions
4439    // within a system header.
4440    if (ASE) {
4441      SourceLocation RBracketLoc = SourceMgr.getSpellingLoc(
4442          ASE->getRBracketLoc());
4443      if (SourceMgr.isInSystemHeader(RBracketLoc)) {
4444        SourceLocation IndexLoc = SourceMgr.getSpellingLoc(
4445            IndexExpr->getLocStart());
4446        if (SourceMgr.isFromSameFile(RBracketLoc, IndexLoc))
4447          return;
4448      }
4449    }
4450
4451    unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds;
4452    if (ASE)
4453      DiagID = diag::warn_array_index_exceeds_bounds;
4454
4455    DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr,
4456                        PDiag(DiagID) << index.toString(10, true)
4457                          << size.toString(10, true)
4458                          << (unsigned)size.getLimitedValue(~0U)
4459                          << IndexExpr->getSourceRange());
4460  } else {
4461    unsigned DiagID = diag::warn_array_index_precedes_bounds;
4462    if (!ASE) {
4463      DiagID = diag::warn_ptr_arith_precedes_bounds;
4464      if (index.isNegative()) index = -index;
4465    }
4466
4467    DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr,
4468                        PDiag(DiagID) << index.toString(10, true)
4469                          << IndexExpr->getSourceRange());
4470  }
4471
4472  if (!ND) {
4473    // Try harder to find a NamedDecl to point at in the note.
4474    while (const ArraySubscriptExpr *ASE =
4475           dyn_cast<ArraySubscriptExpr>(BaseExpr))
4476      BaseExpr = ASE->getBase()->IgnoreParenCasts();
4477    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))
4478      ND = dyn_cast<NamedDecl>(DRE->getDecl());
4479    if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr))
4480      ND = dyn_cast<NamedDecl>(ME->getMemberDecl());
4481  }
4482
4483  if (ND)
4484    DiagRuntimeBehavior(ND->getLocStart(), BaseExpr,
4485                        PDiag(diag::note_array_index_out_of_bounds)
4486                          << ND->getDeclName());
4487}
4488
4489void Sema::CheckArrayAccess(const Expr *expr) {
4490  int AllowOnePastEnd = 0;
4491  while (expr) {
4492    expr = expr->IgnoreParenImpCasts();
4493    switch (expr->getStmtClass()) {
4494      case Stmt::ArraySubscriptExprClass: {
4495        const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr);
4496        CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE,
4497                         AllowOnePastEnd > 0);
4498        return;
4499      }
4500      case Stmt::UnaryOperatorClass: {
4501        // Only unwrap the * and & unary operators
4502        const UnaryOperator *UO = cast<UnaryOperator>(expr);
4503        expr = UO->getSubExpr();
4504        switch (UO->getOpcode()) {
4505          case UO_AddrOf:
4506            AllowOnePastEnd++;
4507            break;
4508          case UO_Deref:
4509            AllowOnePastEnd--;
4510            break;
4511          default:
4512            return;
4513        }
4514        break;
4515      }
4516      case Stmt::ConditionalOperatorClass: {
4517        const ConditionalOperator *cond = cast<ConditionalOperator>(expr);
4518        if (const Expr *lhs = cond->getLHS())
4519          CheckArrayAccess(lhs);
4520        if (const Expr *rhs = cond->getRHS())
4521          CheckArrayAccess(rhs);
4522        return;
4523      }
4524      default:
4525        return;
4526    }
4527  }
4528}
4529
4530//===--- CHECK: Objective-C retain cycles ----------------------------------//
4531
4532namespace {
4533  struct RetainCycleOwner {
4534    RetainCycleOwner() : Variable(0), Indirect(false) {}
4535    VarDecl *Variable;
4536    SourceRange Range;
4537    SourceLocation Loc;
4538    bool Indirect;
4539
4540    void setLocsFrom(Expr *e) {
4541      Loc = e->getExprLoc();
4542      Range = e->getSourceRange();
4543    }
4544  };
4545}
4546
4547/// Consider whether capturing the given variable can possibly lead to
4548/// a retain cycle.
4549static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) {
4550  // In ARC, it's captured strongly iff the variable has __strong
4551  // lifetime.  In MRR, it's captured strongly if the variable is
4552  // __block and has an appropriate type.
4553  if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
4554    return false;
4555
4556  owner.Variable = var;
4557  owner.setLocsFrom(ref);
4558  return true;
4559}
4560
4561static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) {
4562  while (true) {
4563    e = e->IgnoreParens();
4564    if (CastExpr *cast = dyn_cast<CastExpr>(e)) {
4565      switch (cast->getCastKind()) {
4566      case CK_BitCast:
4567      case CK_LValueBitCast:
4568      case CK_LValueToRValue:
4569      case CK_ARCReclaimReturnedObject:
4570        e = cast->getSubExpr();
4571        continue;
4572
4573      default:
4574        return false;
4575      }
4576    }
4577
4578    if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) {
4579      ObjCIvarDecl *ivar = ref->getDecl();
4580      if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
4581        return false;
4582
4583      // Try to find a retain cycle in the base.
4584      if (!findRetainCycleOwner(S, ref->getBase(), owner))
4585        return false;
4586
4587      if (ref->isFreeIvar()) owner.setLocsFrom(ref);
4588      owner.Indirect = true;
4589      return true;
4590    }
4591
4592    if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) {
4593      VarDecl *var = dyn_cast<VarDecl>(ref->getDecl());
4594      if (!var) return false;
4595      return considerVariable(var, ref, owner);
4596    }
4597
4598    if (BlockDeclRefExpr *ref = dyn_cast<BlockDeclRefExpr>(e)) {
4599      owner.Variable = ref->getDecl();
4600      owner.setLocsFrom(ref);
4601      return true;
4602    }
4603
4604    if (MemberExpr *member = dyn_cast<MemberExpr>(e)) {
4605      if (member->isArrow()) return false;
4606
4607      // Don't count this as an indirect ownership.
4608      e = member->getBase();
4609      continue;
4610    }
4611
4612    if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) {
4613      // Only pay attention to pseudo-objects on property references.
4614      ObjCPropertyRefExpr *pre
4615        = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm()
4616                                              ->IgnoreParens());
4617      if (!pre) return false;
4618      if (pre->isImplicitProperty()) return false;
4619      ObjCPropertyDecl *property = pre->getExplicitProperty();
4620      if (!property->isRetaining() &&
4621          !(property->getPropertyIvarDecl() &&
4622            property->getPropertyIvarDecl()->getType()
4623              .getObjCLifetime() == Qualifiers::OCL_Strong))
4624          return false;
4625
4626      owner.Indirect = true;
4627      if (pre->isSuperReceiver()) {
4628        owner.Variable = S.getCurMethodDecl()->getSelfDecl();
4629        if (!owner.Variable)
4630          return false;
4631        owner.Loc = pre->getLocation();
4632        owner.Range = pre->getSourceRange();
4633        return true;
4634      }
4635      e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase())
4636                              ->getSourceExpr());
4637      continue;
4638    }
4639
4640    // Array ivars?
4641
4642    return false;
4643  }
4644}
4645
4646namespace {
4647  struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> {
4648    FindCaptureVisitor(ASTContext &Context, VarDecl *variable)
4649      : EvaluatedExprVisitor<FindCaptureVisitor>(Context),
4650        Variable(variable), Capturer(0) {}
4651
4652    VarDecl *Variable;
4653    Expr *Capturer;
4654
4655    void VisitDeclRefExpr(DeclRefExpr *ref) {
4656      if (ref->getDecl() == Variable && !Capturer)
4657        Capturer = ref;
4658    }
4659
4660    void VisitBlockDeclRefExpr(BlockDeclRefExpr *ref) {
4661      if (ref->getDecl() == Variable && !Capturer)
4662        Capturer = ref;
4663    }
4664
4665    void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) {
4666      if (Capturer) return;
4667      Visit(ref->getBase());
4668      if (Capturer && ref->isFreeIvar())
4669        Capturer = ref;
4670    }
4671
4672    void VisitBlockExpr(BlockExpr *block) {
4673      // Look inside nested blocks
4674      if (block->getBlockDecl()->capturesVariable(Variable))
4675        Visit(block->getBlockDecl()->getBody());
4676    }
4677  };
4678}
4679
4680/// Check whether the given argument is a block which captures a
4681/// variable.
4682static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) {
4683  assert(owner.Variable && owner.Loc.isValid());
4684
4685  e = e->IgnoreParenCasts();
4686  BlockExpr *block = dyn_cast<BlockExpr>(e);
4687  if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable))
4688    return 0;
4689
4690  FindCaptureVisitor visitor(S.Context, owner.Variable);
4691  visitor.Visit(block->getBlockDecl()->getBody());
4692  return visitor.Capturer;
4693}
4694
4695static void diagnoseRetainCycle(Sema &S, Expr *capturer,
4696                                RetainCycleOwner &owner) {
4697  assert(capturer);
4698  assert(owner.Variable && owner.Loc.isValid());
4699
4700  S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle)
4701    << owner.Variable << capturer->getSourceRange();
4702  S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner)
4703    << owner.Indirect << owner.Range;
4704}
4705
4706/// Check for a keyword selector that starts with the word 'add' or
4707/// 'set'.
4708static bool isSetterLikeSelector(Selector sel) {
4709  if (sel.isUnarySelector()) return false;
4710
4711  StringRef str = sel.getNameForSlot(0);
4712  while (!str.empty() && str.front() == '_') str = str.substr(1);
4713  if (str.startswith("set"))
4714    str = str.substr(3);
4715  else if (str.startswith("add")) {
4716    // Specially whitelist 'addOperationWithBlock:'.
4717    if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock"))
4718      return false;
4719    str = str.substr(3);
4720  }
4721  else
4722    return false;
4723
4724  if (str.empty()) return true;
4725  return !islower(str.front());
4726}
4727
4728/// Check a message send to see if it's likely to cause a retain cycle.
4729void Sema::checkRetainCycles(ObjCMessageExpr *msg) {
4730  // Only check instance methods whose selector looks like a setter.
4731  if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector()))
4732    return;
4733
4734  // Try to find a variable that the receiver is strongly owned by.
4735  RetainCycleOwner owner;
4736  if (msg->getReceiverKind() == ObjCMessageExpr::Instance) {
4737    if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner))
4738      return;
4739  } else {
4740    assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance);
4741    owner.Variable = getCurMethodDecl()->getSelfDecl();
4742    owner.Loc = msg->getSuperLoc();
4743    owner.Range = msg->getSuperLoc();
4744  }
4745
4746  // Check whether the receiver is captured by any of the arguments.
4747  for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i)
4748    if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner))
4749      return diagnoseRetainCycle(*this, capturer, owner);
4750}
4751
4752/// Check a property assign to see if it's likely to cause a retain cycle.
4753void Sema::checkRetainCycles(Expr *receiver, Expr *argument) {
4754  RetainCycleOwner owner;
4755  if (!findRetainCycleOwner(*this, receiver, owner))
4756    return;
4757
4758  if (Expr *capturer = findCapturingExpr(*this, argument, owner))
4759    diagnoseRetainCycle(*this, capturer, owner);
4760}
4761
4762bool Sema::checkUnsafeAssigns(SourceLocation Loc,
4763                              QualType LHS, Expr *RHS) {
4764  Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime();
4765  if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone)
4766    return false;
4767  // strip off any implicit cast added to get to the one arc-specific
4768  while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) {
4769    if (cast->getCastKind() == CK_ARCConsumeObject) {
4770      Diag(Loc, diag::warn_arc_retained_assign)
4771        << (LT == Qualifiers::OCL_ExplicitNone)
4772        << RHS->getSourceRange();
4773      return true;
4774    }
4775    RHS = cast->getSubExpr();
4776  }
4777  return false;
4778}
4779
4780void Sema::checkUnsafeExprAssigns(SourceLocation Loc,
4781                              Expr *LHS, Expr *RHS) {
4782  QualType LHSType;
4783  // PropertyRef on LHS type need be directly obtained from
4784  // its declaration as it has a PsuedoType.
4785  ObjCPropertyRefExpr *PRE
4786    = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens());
4787  if (PRE && !PRE->isImplicitProperty()) {
4788    const ObjCPropertyDecl *PD = PRE->getExplicitProperty();
4789    if (PD)
4790      LHSType = PD->getType();
4791  }
4792
4793  if (LHSType.isNull())
4794    LHSType = LHS->getType();
4795  if (checkUnsafeAssigns(Loc, LHSType, RHS))
4796    return;
4797  Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime();
4798  // FIXME. Check for other life times.
4799  if (LT != Qualifiers::OCL_None)
4800    return;
4801
4802  if (PRE) {
4803    if (PRE->isImplicitProperty())
4804      return;
4805    const ObjCPropertyDecl *PD = PRE->getExplicitProperty();
4806    if (!PD)
4807      return;
4808
4809    unsigned Attributes = PD->getPropertyAttributes();
4810    if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) {
4811      // when 'assign' attribute was not explicitly specified
4812      // by user, ignore it and rely on property type itself
4813      // for lifetime info.
4814      unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten();
4815      if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) &&
4816          LHSType->isObjCRetainableType())
4817        return;
4818
4819      while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) {
4820        if (cast->getCastKind() == CK_ARCConsumeObject) {
4821          Diag(Loc, diag::warn_arc_retained_property_assign)
4822          << RHS->getSourceRange();
4823          return;
4824        }
4825        RHS = cast->getSubExpr();
4826      }
4827    }
4828  }
4829}
4830
4831//===--- CHECK: Empty statement body (-Wempty-body) ---------------------===//
4832
4833namespace {
4834bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr,
4835                                 SourceLocation StmtLoc,
4836                                 const NullStmt *Body) {
4837  // Do not warn if the body is a macro that expands to nothing, e.g:
4838  //
4839  // #define CALL(x)
4840  // if (condition)
4841  //   CALL(0);
4842  //
4843  if (Body->hasLeadingEmptyMacro())
4844    return false;
4845
4846  // Get line numbers of statement and body.
4847  bool StmtLineInvalid;
4848  unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc,
4849                                                      &StmtLineInvalid);
4850  if (StmtLineInvalid)
4851    return false;
4852
4853  bool BodyLineInvalid;
4854  unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(),
4855                                                      &BodyLineInvalid);
4856  if (BodyLineInvalid)
4857    return false;
4858
4859  // Warn if null statement and body are on the same line.
4860  if (StmtLine != BodyLine)
4861    return false;
4862
4863  return true;
4864}
4865} // Unnamed namespace
4866
4867void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc,
4868                                 const Stmt *Body,
4869                                 unsigned DiagID) {
4870  // Since this is a syntactic check, don't emit diagnostic for template
4871  // instantiations, this just adds noise.
4872  if (CurrentInstantiationScope)
4873    return;
4874
4875  // The body should be a null statement.
4876  const NullStmt *NBody = dyn_cast<NullStmt>(Body);
4877  if (!NBody)
4878    return;
4879
4880  // Do the usual checks.
4881  if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody))
4882    return;
4883
4884  Diag(NBody->getSemiLoc(), DiagID);
4885  Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line);
4886}
4887
4888void Sema::DiagnoseEmptyLoopBody(const Stmt *S,
4889                                 const Stmt *PossibleBody) {
4890  assert(!CurrentInstantiationScope); // Ensured by caller
4891
4892  SourceLocation StmtLoc;
4893  const Stmt *Body;
4894  unsigned DiagID;
4895  if (const ForStmt *FS = dyn_cast<ForStmt>(S)) {
4896    StmtLoc = FS->getRParenLoc();
4897    Body = FS->getBody();
4898    DiagID = diag::warn_empty_for_body;
4899  } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) {
4900    StmtLoc = WS->getCond()->getSourceRange().getEnd();
4901    Body = WS->getBody();
4902    DiagID = diag::warn_empty_while_body;
4903  } else
4904    return; // Neither `for' nor `while'.
4905
4906  // The body should be a null statement.
4907  const NullStmt *NBody = dyn_cast<NullStmt>(Body);
4908  if (!NBody)
4909    return;
4910
4911  // Skip expensive checks if diagnostic is disabled.
4912  if (Diags.getDiagnosticLevel(DiagID, NBody->getSemiLoc()) ==
4913          DiagnosticsEngine::Ignored)
4914    return;
4915
4916  // Do the usual checks.
4917  if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody))
4918    return;
4919
4920  // `for(...);' and `while(...);' are popular idioms, so in order to keep
4921  // noise level low, emit diagnostics only if for/while is followed by a
4922  // CompoundStmt, e.g.:
4923  //    for (int i = 0; i < n; i++);
4924  //    {
4925  //      a(i);
4926  //    }
4927  // or if for/while is followed by a statement with more indentation
4928  // than for/while itself:
4929  //    for (int i = 0; i < n; i++);
4930  //      a(i);
4931  bool ProbableTypo = isa<CompoundStmt>(PossibleBody);
4932  if (!ProbableTypo) {
4933    bool BodyColInvalid;
4934    unsigned BodyCol = SourceMgr.getPresumedColumnNumber(
4935                             PossibleBody->getLocStart(),
4936                             &BodyColInvalid);
4937    if (BodyColInvalid)
4938      return;
4939
4940    bool StmtColInvalid;
4941    unsigned StmtCol = SourceMgr.getPresumedColumnNumber(
4942                             S->getLocStart(),
4943                             &StmtColInvalid);
4944    if (StmtColInvalid)
4945      return;
4946
4947    if (BodyCol > StmtCol)
4948      ProbableTypo = true;
4949  }
4950
4951  if (ProbableTypo) {
4952    Diag(NBody->getSemiLoc(), DiagID);
4953    Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line);
4954  }
4955}
4956
4957