SemaChecking.cpp revision be6126a2a784e1446460b8d15c2b26f880c871fc
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 S.Context, IsObjCLiteral); 2186 2187 if (success) { 2188 // Get the fix string from the fixed format specifier 2189 SmallString<128> buf; 2190 llvm::raw_svector_ostream os(buf); 2191 fixedFS.toString(os); 2192 2193 EmitFormatDiagnostic( 2194 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2195 << ATR.getRepresentativeTypeName(S.Context) << Ex->getType() 2196 << Ex->getSourceRange(), 2197 getLocationOfByte(CS.getStart()), 2198 /*IsStringLocation*/true, 2199 getSpecifierRange(startSpecifier, specifierLen), 2200 FixItHint::CreateReplacement( 2201 getSpecifierRange(startSpecifier, specifierLen), 2202 os.str())); 2203 } 2204 else { 2205 EmitFormatDiagnostic( 2206 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2207 << ATR.getRepresentativeTypeName(S.Context) << Ex->getType() 2208 << getSpecifierRange(startSpecifier, specifierLen) 2209 << Ex->getSourceRange(), 2210 getLocationOfByte(CS.getStart()), 2211 true, 2212 getSpecifierRange(startSpecifier, specifierLen)); 2213 } 2214 } 2215 2216 return true; 2217} 2218 2219//===--- CHECK: Scanf format string checking ------------------------------===// 2220 2221namespace { 2222class CheckScanfHandler : public CheckFormatHandler { 2223public: 2224 CheckScanfHandler(Sema &s, const StringLiteral *fexpr, 2225 const Expr *origFormatExpr, unsigned firstDataArg, 2226 unsigned numDataArgs, bool isObjCLiteral, 2227 const char *beg, bool hasVAListArg, 2228 Expr **Args, unsigned NumArgs, 2229 unsigned formatIdx, bool inFunctionCall) 2230 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 2231 numDataArgs, isObjCLiteral, beg, hasVAListArg, 2232 Args, NumArgs, formatIdx, inFunctionCall) {} 2233 2234 bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS, 2235 const char *startSpecifier, 2236 unsigned specifierLen); 2237 2238 bool HandleInvalidScanfConversionSpecifier( 2239 const analyze_scanf::ScanfSpecifier &FS, 2240 const char *startSpecifier, 2241 unsigned specifierLen); 2242 2243 void HandleIncompleteScanList(const char *start, const char *end); 2244}; 2245} 2246 2247void CheckScanfHandler::HandleIncompleteScanList(const char *start, 2248 const char *end) { 2249 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete), 2250 getLocationOfByte(end), /*IsStringLocation*/true, 2251 getSpecifierRange(start, end - start)); 2252} 2253 2254bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier( 2255 const analyze_scanf::ScanfSpecifier &FS, 2256 const char *startSpecifier, 2257 unsigned specifierLen) { 2258 2259 const analyze_scanf::ScanfConversionSpecifier &CS = 2260 FS.getConversionSpecifier(); 2261 2262 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 2263 getLocationOfByte(CS.getStart()), 2264 startSpecifier, specifierLen, 2265 CS.getStart(), CS.getLength()); 2266} 2267 2268bool CheckScanfHandler::HandleScanfSpecifier( 2269 const analyze_scanf::ScanfSpecifier &FS, 2270 const char *startSpecifier, 2271 unsigned specifierLen) { 2272 2273 using namespace analyze_scanf; 2274 using namespace analyze_format_string; 2275 2276 const ScanfConversionSpecifier &CS = FS.getConversionSpecifier(); 2277 2278 // Handle case where '%' and '*' don't consume an argument. These shouldn't 2279 // be used to decide if we are using positional arguments consistently. 2280 if (FS.consumesDataArgument()) { 2281 if (atFirstArg) { 2282 atFirstArg = false; 2283 usesPositionalArgs = FS.usesPositionalArg(); 2284 } 2285 else if (usesPositionalArgs != FS.usesPositionalArg()) { 2286 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 2287 startSpecifier, specifierLen); 2288 return false; 2289 } 2290 } 2291 2292 // Check if the field with is non-zero. 2293 const OptionalAmount &Amt = FS.getFieldWidth(); 2294 if (Amt.getHowSpecified() == OptionalAmount::Constant) { 2295 if (Amt.getConstantAmount() == 0) { 2296 const CharSourceRange &R = getSpecifierRange(Amt.getStart(), 2297 Amt.getConstantLength()); 2298 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width), 2299 getLocationOfByte(Amt.getStart()), 2300 /*IsStringLocation*/true, R, 2301 FixItHint::CreateRemoval(R)); 2302 } 2303 } 2304 2305 if (!FS.consumesDataArgument()) { 2306 // FIXME: Technically specifying a precision or field width here 2307 // makes no sense. Worth issuing a warning at some point. 2308 return true; 2309 } 2310 2311 // Consume the argument. 2312 unsigned argIndex = FS.getArgIndex(); 2313 if (argIndex < NumDataArgs) { 2314 // The check to see if the argIndex is valid will come later. 2315 // We set the bit here because we may exit early from this 2316 // function if we encounter some other error. 2317 CoveredArgs.set(argIndex); 2318 } 2319 2320 // Check the length modifier is valid with the given conversion specifier. 2321 const LengthModifier &LM = FS.getLengthModifier(); 2322 if (!FS.hasValidLengthModifier()) { 2323 const CharSourceRange &R = getSpecifierRange(LM.getStart(), LM.getLength()); 2324 EmitFormatDiagnostic(S.PDiag(diag::warn_format_nonsensical_length) 2325 << LM.toString() << CS.toString() 2326 << getSpecifierRange(startSpecifier, specifierLen), 2327 getLocationOfByte(LM.getStart()), 2328 /*IsStringLocation*/true, R, 2329 FixItHint::CreateRemoval(R)); 2330 } 2331 2332 // The remaining checks depend on the data arguments. 2333 if (HasVAListArg) 2334 return true; 2335 2336 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 2337 return false; 2338 2339 // Check that the argument type matches the format specifier. 2340 const Expr *Ex = getDataArg(argIndex); 2341 const analyze_scanf::ScanfArgTypeResult &ATR = FS.getArgType(S.Context); 2342 if (ATR.isValid() && !ATR.matchesType(S.Context, Ex->getType())) { 2343 ScanfSpecifier fixedFS = FS; 2344 bool success = fixedFS.fixType(Ex->getType(), S.getLangOptions(), 2345 S.Context); 2346 2347 if (success) { 2348 // Get the fix string from the fixed format specifier. 2349 SmallString<128> buf; 2350 llvm::raw_svector_ostream os(buf); 2351 fixedFS.toString(os); 2352 2353 EmitFormatDiagnostic( 2354 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2355 << ATR.getRepresentativeTypeName(S.Context) << Ex->getType() 2356 << Ex->getSourceRange(), 2357 getLocationOfByte(CS.getStart()), 2358 /*IsStringLocation*/true, 2359 getSpecifierRange(startSpecifier, specifierLen), 2360 FixItHint::CreateReplacement( 2361 getSpecifierRange(startSpecifier, specifierLen), 2362 os.str())); 2363 } else { 2364 EmitFormatDiagnostic( 2365 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2366 << ATR.getRepresentativeTypeName(S.Context) << Ex->getType() 2367 << Ex->getSourceRange(), 2368 getLocationOfByte(CS.getStart()), 2369 /*IsStringLocation*/true, 2370 getSpecifierRange(startSpecifier, specifierLen)); 2371 } 2372 } 2373 2374 return true; 2375} 2376 2377void Sema::CheckFormatString(const StringLiteral *FExpr, 2378 const Expr *OrigFormatExpr, 2379 Expr **Args, unsigned NumArgs, 2380 bool HasVAListArg, unsigned format_idx, 2381 unsigned firstDataArg, FormatStringType Type, 2382 bool inFunctionCall) { 2383 2384 // CHECK: is the format string a wide literal? 2385 if (!FExpr->isAscii()) { 2386 CheckFormatHandler::EmitFormatDiagnostic( 2387 *this, inFunctionCall, Args[format_idx], 2388 PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(), 2389 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 2390 return; 2391 } 2392 2393 // Str - The format string. NOTE: this is NOT null-terminated! 2394 StringRef StrRef = FExpr->getString(); 2395 const char *Str = StrRef.data(); 2396 unsigned StrLen = StrRef.size(); 2397 const unsigned numDataArgs = NumArgs - firstDataArg; 2398 2399 // CHECK: empty format string? 2400 if (StrLen == 0 && numDataArgs > 0) { 2401 CheckFormatHandler::EmitFormatDiagnostic( 2402 *this, inFunctionCall, Args[format_idx], 2403 PDiag(diag::warn_empty_format_string), FExpr->getLocStart(), 2404 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 2405 return; 2406 } 2407 2408 if (Type == FST_Printf || Type == FST_NSString) { 2409 CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 2410 numDataArgs, isa<ObjCStringLiteral>(OrigFormatExpr), 2411 Str, HasVAListArg, Args, NumArgs, format_idx, 2412 inFunctionCall); 2413 2414 if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen, 2415 getLangOptions())) 2416 H.DoneProcessing(); 2417 } else if (Type == FST_Scanf) { 2418 CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 2419 numDataArgs, isa<ObjCStringLiteral>(OrigFormatExpr), 2420 Str, HasVAListArg, Args, NumArgs, format_idx, 2421 inFunctionCall); 2422 2423 if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen, 2424 getLangOptions())) 2425 H.DoneProcessing(); 2426 } // TODO: handle other formats 2427} 2428 2429//===--- CHECK: Standard memory functions ---------------------------------===// 2430 2431/// \brief Determine whether the given type is a dynamic class type (e.g., 2432/// whether it has a vtable). 2433static bool isDynamicClassType(QualType T) { 2434 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) 2435 if (CXXRecordDecl *Definition = Record->getDefinition()) 2436 if (Definition->isDynamicClass()) 2437 return true; 2438 2439 return false; 2440} 2441 2442/// \brief If E is a sizeof expression, returns its argument expression, 2443/// otherwise returns NULL. 2444static const Expr *getSizeOfExprArg(const Expr* E) { 2445 if (const UnaryExprOrTypeTraitExpr *SizeOf = 2446 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 2447 if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType()) 2448 return SizeOf->getArgumentExpr()->IgnoreParenImpCasts(); 2449 2450 return 0; 2451} 2452 2453/// \brief If E is a sizeof expression, returns its argument type. 2454static QualType getSizeOfArgType(const Expr* E) { 2455 if (const UnaryExprOrTypeTraitExpr *SizeOf = 2456 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 2457 if (SizeOf->getKind() == clang::UETT_SizeOf) 2458 return SizeOf->getTypeOfArgument(); 2459 2460 return QualType(); 2461} 2462 2463/// \brief Check for dangerous or invalid arguments to memset(). 2464/// 2465/// This issues warnings on known problematic, dangerous or unspecified 2466/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp' 2467/// function calls. 2468/// 2469/// \param Call The call expression to diagnose. 2470void Sema::CheckMemaccessArguments(const CallExpr *Call, 2471 unsigned BId, 2472 IdentifierInfo *FnName) { 2473 assert(BId != 0); 2474 2475 // It is possible to have a non-standard definition of memset. Validate 2476 // we have enough arguments, and if not, abort further checking. 2477 unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3); 2478 if (Call->getNumArgs() < ExpectedNumArgs) 2479 return; 2480 2481 unsigned LastArg = (BId == Builtin::BImemset || 2482 BId == Builtin::BIstrndup ? 1 : 2); 2483 unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2); 2484 const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts(); 2485 2486 // We have special checking when the length is a sizeof expression. 2487 QualType SizeOfArgTy = getSizeOfArgType(LenExpr); 2488 const Expr *SizeOfArg = getSizeOfExprArg(LenExpr); 2489 llvm::FoldingSetNodeID SizeOfArgID; 2490 2491 for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) { 2492 const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts(); 2493 SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange(); 2494 2495 QualType DestTy = Dest->getType(); 2496 if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) { 2497 QualType PointeeTy = DestPtrTy->getPointeeType(); 2498 2499 // Never warn about void type pointers. This can be used to suppress 2500 // false positives. 2501 if (PointeeTy->isVoidType()) 2502 continue; 2503 2504 // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by 2505 // actually comparing the expressions for equality. Because computing the 2506 // expression IDs can be expensive, we only do this if the diagnostic is 2507 // enabled. 2508 if (SizeOfArg && 2509 Diags.getDiagnosticLevel(diag::warn_sizeof_pointer_expr_memaccess, 2510 SizeOfArg->getExprLoc())) { 2511 // We only compute IDs for expressions if the warning is enabled, and 2512 // cache the sizeof arg's ID. 2513 if (SizeOfArgID == llvm::FoldingSetNodeID()) 2514 SizeOfArg->Profile(SizeOfArgID, Context, true); 2515 llvm::FoldingSetNodeID DestID; 2516 Dest->Profile(DestID, Context, true); 2517 if (DestID == SizeOfArgID) { 2518 // TODO: For strncpy() and friends, this could suggest sizeof(dst) 2519 // over sizeof(src) as well. 2520 unsigned ActionIdx = 0; // Default is to suggest dereferencing. 2521 if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest)) 2522 if (UnaryOp->getOpcode() == UO_AddrOf) 2523 ActionIdx = 1; // If its an address-of operator, just remove it. 2524 if (Context.getTypeSize(PointeeTy) == Context.getCharWidth()) 2525 ActionIdx = 2; // If the pointee's size is sizeof(char), 2526 // suggest an explicit length. 2527 unsigned DestSrcSelect = 2528 (BId == Builtin::BIstrndup ? 1 : ArgIdx); 2529 DiagRuntimeBehavior(SizeOfArg->getExprLoc(), Dest, 2530 PDiag(diag::warn_sizeof_pointer_expr_memaccess) 2531 << FnName << DestSrcSelect << ActionIdx 2532 << Dest->getSourceRange() 2533 << SizeOfArg->getSourceRange()); 2534 break; 2535 } 2536 } 2537 2538 // Also check for cases where the sizeof argument is the exact same 2539 // type as the memory argument, and where it points to a user-defined 2540 // record type. 2541 if (SizeOfArgTy != QualType()) { 2542 if (PointeeTy->isRecordType() && 2543 Context.typesAreCompatible(SizeOfArgTy, DestTy)) { 2544 DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest, 2545 PDiag(diag::warn_sizeof_pointer_type_memaccess) 2546 << FnName << SizeOfArgTy << ArgIdx 2547 << PointeeTy << Dest->getSourceRange() 2548 << LenExpr->getSourceRange()); 2549 break; 2550 } 2551 } 2552 2553 // Always complain about dynamic classes. 2554 if (isDynamicClassType(PointeeTy)) { 2555 2556 unsigned OperationType = 0; 2557 // "overwritten" if we're warning about the destination for any call 2558 // but memcmp; otherwise a verb appropriate to the call. 2559 if (ArgIdx != 0 || BId == Builtin::BImemcmp) { 2560 if (BId == Builtin::BImemcpy) 2561 OperationType = 1; 2562 else if(BId == Builtin::BImemmove) 2563 OperationType = 2; 2564 else if (BId == Builtin::BImemcmp) 2565 OperationType = 3; 2566 } 2567 2568 DiagRuntimeBehavior( 2569 Dest->getExprLoc(), Dest, 2570 PDiag(diag::warn_dyn_class_memaccess) 2571 << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx) 2572 << FnName << PointeeTy 2573 << OperationType 2574 << Call->getCallee()->getSourceRange()); 2575 } else if (PointeeTy.hasNonTrivialObjCLifetime() && 2576 BId != Builtin::BImemset) 2577 DiagRuntimeBehavior( 2578 Dest->getExprLoc(), Dest, 2579 PDiag(diag::warn_arc_object_memaccess) 2580 << ArgIdx << FnName << PointeeTy 2581 << Call->getCallee()->getSourceRange()); 2582 else 2583 continue; 2584 2585 DiagRuntimeBehavior( 2586 Dest->getExprLoc(), Dest, 2587 PDiag(diag::note_bad_memaccess_silence) 2588 << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)")); 2589 break; 2590 } 2591 } 2592} 2593 2594// A little helper routine: ignore addition and subtraction of integer literals. 2595// This intentionally does not ignore all integer constant expressions because 2596// we don't want to remove sizeof(). 2597static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) { 2598 Ex = Ex->IgnoreParenCasts(); 2599 2600 for (;;) { 2601 const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex); 2602 if (!BO || !BO->isAdditiveOp()) 2603 break; 2604 2605 const Expr *RHS = BO->getRHS()->IgnoreParenCasts(); 2606 const Expr *LHS = BO->getLHS()->IgnoreParenCasts(); 2607 2608 if (isa<IntegerLiteral>(RHS)) 2609 Ex = LHS; 2610 else if (isa<IntegerLiteral>(LHS)) 2611 Ex = RHS; 2612 else 2613 break; 2614 } 2615 2616 return Ex; 2617} 2618 2619// Warn if the user has made the 'size' argument to strlcpy or strlcat 2620// be the size of the source, instead of the destination. 2621void Sema::CheckStrlcpycatArguments(const CallExpr *Call, 2622 IdentifierInfo *FnName) { 2623 2624 // Don't crash if the user has the wrong number of arguments 2625 if (Call->getNumArgs() != 3) 2626 return; 2627 2628 const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context); 2629 const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context); 2630 const Expr *CompareWithSrc = NULL; 2631 2632 // Look for 'strlcpy(dst, x, sizeof(x))' 2633 if (const Expr *Ex = getSizeOfExprArg(SizeArg)) 2634 CompareWithSrc = Ex; 2635 else { 2636 // Look for 'strlcpy(dst, x, strlen(x))' 2637 if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) { 2638 if (SizeCall->isBuiltinCall() == Builtin::BIstrlen 2639 && SizeCall->getNumArgs() == 1) 2640 CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context); 2641 } 2642 } 2643 2644 if (!CompareWithSrc) 2645 return; 2646 2647 // Determine if the argument to sizeof/strlen is equal to the source 2648 // argument. In principle there's all kinds of things you could do 2649 // here, for instance creating an == expression and evaluating it with 2650 // EvaluateAsBooleanCondition, but this uses a more direct technique: 2651 const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg); 2652 if (!SrcArgDRE) 2653 return; 2654 2655 const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc); 2656 if (!CompareWithSrcDRE || 2657 SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl()) 2658 return; 2659 2660 const Expr *OriginalSizeArg = Call->getArg(2); 2661 Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size) 2662 << OriginalSizeArg->getSourceRange() << FnName; 2663 2664 // Output a FIXIT hint if the destination is an array (rather than a 2665 // pointer to an array). This could be enhanced to handle some 2666 // pointers if we know the actual size, like if DstArg is 'array+2' 2667 // we could say 'sizeof(array)-2'. 2668 const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts(); 2669 QualType DstArgTy = DstArg->getType(); 2670 2671 // Only handle constant-sized or VLAs, but not flexible members. 2672 if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(DstArgTy)) { 2673 // Only issue the FIXIT for arrays of size > 1. 2674 if (CAT->getSize().getSExtValue() <= 1) 2675 return; 2676 } else if (!DstArgTy->isVariableArrayType()) { 2677 return; 2678 } 2679 2680 SmallString<128> sizeString; 2681 llvm::raw_svector_ostream OS(sizeString); 2682 OS << "sizeof("; 2683 DstArg->printPretty(OS, Context, 0, getPrintingPolicy()); 2684 OS << ")"; 2685 2686 Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size) 2687 << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(), 2688 OS.str()); 2689} 2690 2691/// Check if two expressions refer to the same declaration. 2692static bool referToTheSameDecl(const Expr *E1, const Expr *E2) { 2693 if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1)) 2694 if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2)) 2695 return D1->getDecl() == D2->getDecl(); 2696 return false; 2697} 2698 2699static const Expr *getStrlenExprArg(const Expr *E) { 2700 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 2701 const FunctionDecl *FD = CE->getDirectCallee(); 2702 if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen) 2703 return 0; 2704 return CE->getArg(0)->IgnoreParenCasts(); 2705 } 2706 return 0; 2707} 2708 2709// Warn on anti-patterns as the 'size' argument to strncat. 2710// The correct size argument should look like following: 2711// strncat(dst, src, sizeof(dst) - strlen(dest) - 1); 2712void Sema::CheckStrncatArguments(const CallExpr *CE, 2713 IdentifierInfo *FnName) { 2714 // Don't crash if the user has the wrong number of arguments. 2715 if (CE->getNumArgs() < 3) 2716 return; 2717 const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts(); 2718 const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts(); 2719 const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts(); 2720 2721 // Identify common expressions, which are wrongly used as the size argument 2722 // to strncat and may lead to buffer overflows. 2723 unsigned PatternType = 0; 2724 if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) { 2725 // - sizeof(dst) 2726 if (referToTheSameDecl(SizeOfArg, DstArg)) 2727 PatternType = 1; 2728 // - sizeof(src) 2729 else if (referToTheSameDecl(SizeOfArg, SrcArg)) 2730 PatternType = 2; 2731 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) { 2732 if (BE->getOpcode() == BO_Sub) { 2733 const Expr *L = BE->getLHS()->IgnoreParenCasts(); 2734 const Expr *R = BE->getRHS()->IgnoreParenCasts(); 2735 // - sizeof(dst) - strlen(dst) 2736 if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) && 2737 referToTheSameDecl(DstArg, getStrlenExprArg(R))) 2738 PatternType = 1; 2739 // - sizeof(src) - (anything) 2740 else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L))) 2741 PatternType = 2; 2742 } 2743 } 2744 2745 if (PatternType == 0) 2746 return; 2747 2748 // Generate the diagnostic. 2749 SourceLocation SL = LenArg->getLocStart(); 2750 SourceRange SR = LenArg->getSourceRange(); 2751 SourceManager &SM = PP.getSourceManager(); 2752 2753 // If the function is defined as a builtin macro, do not show macro expansion. 2754 if (SM.isMacroArgExpansion(SL)) { 2755 SL = SM.getSpellingLoc(SL); 2756 SR = SourceRange(SM.getSpellingLoc(SR.getBegin()), 2757 SM.getSpellingLoc(SR.getEnd())); 2758 } 2759 2760 if (PatternType == 1) 2761 Diag(SL, diag::warn_strncat_large_size) << SR; 2762 else 2763 Diag(SL, diag::warn_strncat_src_size) << SR; 2764 2765 // Output a FIXIT hint if the destination is an array (rather than a 2766 // pointer to an array). This could be enhanced to handle some 2767 // pointers if we know the actual size, like if DstArg is 'array+2' 2768 // we could say 'sizeof(array)-2'. 2769 QualType DstArgTy = DstArg->getType(); 2770 2771 // Only handle constant-sized or VLAs, but not flexible members. 2772 if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(DstArgTy)) { 2773 // Only issue the FIXIT for arrays of size > 1. 2774 if (CAT->getSize().getSExtValue() <= 1) 2775 return; 2776 } else if (!DstArgTy->isVariableArrayType()) { 2777 return; 2778 } 2779 2780 SmallString<128> sizeString; 2781 llvm::raw_svector_ostream OS(sizeString); 2782 OS << "sizeof("; 2783 DstArg->printPretty(OS, Context, 0, getPrintingPolicy()); 2784 OS << ") - "; 2785 OS << "strlen("; 2786 DstArg->printPretty(OS, Context, 0, getPrintingPolicy()); 2787 OS << ") - 1"; 2788 2789 Diag(SL, diag::note_strncat_wrong_size) 2790 << FixItHint::CreateReplacement(SR, OS.str()); 2791} 2792 2793//===--- CHECK: Return Address of Stack Variable --------------------------===// 2794 2795static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars); 2796static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars); 2797 2798/// CheckReturnStackAddr - Check if a return statement returns the address 2799/// of a stack variable. 2800void 2801Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType, 2802 SourceLocation ReturnLoc) { 2803 2804 Expr *stackE = 0; 2805 SmallVector<DeclRefExpr *, 8> refVars; 2806 2807 // Perform checking for returned stack addresses, local blocks, 2808 // label addresses or references to temporaries. 2809 if (lhsType->isPointerType() || 2810 (!getLangOptions().ObjCAutoRefCount && lhsType->isBlockPointerType())) { 2811 stackE = EvalAddr(RetValExp, refVars); 2812 } else if (lhsType->isReferenceType()) { 2813 stackE = EvalVal(RetValExp, refVars); 2814 } 2815 2816 if (stackE == 0) 2817 return; // Nothing suspicious was found. 2818 2819 SourceLocation diagLoc; 2820 SourceRange diagRange; 2821 if (refVars.empty()) { 2822 diagLoc = stackE->getLocStart(); 2823 diagRange = stackE->getSourceRange(); 2824 } else { 2825 // We followed through a reference variable. 'stackE' contains the 2826 // problematic expression but we will warn at the return statement pointing 2827 // at the reference variable. We will later display the "trail" of 2828 // reference variables using notes. 2829 diagLoc = refVars[0]->getLocStart(); 2830 diagRange = refVars[0]->getSourceRange(); 2831 } 2832 2833 if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var. 2834 Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref 2835 : diag::warn_ret_stack_addr) 2836 << DR->getDecl()->getDeclName() << diagRange; 2837 } else if (isa<BlockExpr>(stackE)) { // local block. 2838 Diag(diagLoc, diag::err_ret_local_block) << diagRange; 2839 } else if (isa<AddrLabelExpr>(stackE)) { // address of label. 2840 Diag(diagLoc, diag::warn_ret_addr_label) << diagRange; 2841 } else { // local temporary. 2842 Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref 2843 : diag::warn_ret_local_temp_addr) 2844 << diagRange; 2845 } 2846 2847 // Display the "trail" of reference variables that we followed until we 2848 // found the problematic expression using notes. 2849 for (unsigned i = 0, e = refVars.size(); i != e; ++i) { 2850 VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl()); 2851 // If this var binds to another reference var, show the range of the next 2852 // var, otherwise the var binds to the problematic expression, in which case 2853 // show the range of the expression. 2854 SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange() 2855 : stackE->getSourceRange(); 2856 Diag(VD->getLocation(), diag::note_ref_var_local_bind) 2857 << VD->getDeclName() << range; 2858 } 2859} 2860 2861/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that 2862/// check if the expression in a return statement evaluates to an address 2863/// to a location on the stack, a local block, an address of a label, or a 2864/// reference to local temporary. The recursion is used to traverse the 2865/// AST of the return expression, with recursion backtracking when we 2866/// encounter a subexpression that (1) clearly does not lead to one of the 2867/// above problematic expressions (2) is something we cannot determine leads to 2868/// a problematic expression based on such local checking. 2869/// 2870/// Both EvalAddr and EvalVal follow through reference variables to evaluate 2871/// the expression that they point to. Such variables are added to the 2872/// 'refVars' vector so that we know what the reference variable "trail" was. 2873/// 2874/// EvalAddr processes expressions that are pointers that are used as 2875/// references (and not L-values). EvalVal handles all other values. 2876/// At the base case of the recursion is a check for the above problematic 2877/// expressions. 2878/// 2879/// This implementation handles: 2880/// 2881/// * pointer-to-pointer casts 2882/// * implicit conversions from array references to pointers 2883/// * taking the address of fields 2884/// * arbitrary interplay between "&" and "*" operators 2885/// * pointer arithmetic from an address of a stack variable 2886/// * taking the address of an array element where the array is on the stack 2887static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars) { 2888 if (E->isTypeDependent()) 2889 return NULL; 2890 2891 // We should only be called for evaluating pointer expressions. 2892 assert((E->getType()->isAnyPointerType() || 2893 E->getType()->isBlockPointerType() || 2894 E->getType()->isObjCQualifiedIdType()) && 2895 "EvalAddr only works on pointers"); 2896 2897 E = E->IgnoreParens(); 2898 2899 // Our "symbolic interpreter" is just a dispatch off the currently 2900 // viewed AST node. We then recursively traverse the AST by calling 2901 // EvalAddr and EvalVal appropriately. 2902 switch (E->getStmtClass()) { 2903 case Stmt::DeclRefExprClass: { 2904 DeclRefExpr *DR = cast<DeclRefExpr>(E); 2905 2906 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) 2907 // If this is a reference variable, follow through to the expression that 2908 // it points to. 2909 if (V->hasLocalStorage() && 2910 V->getType()->isReferenceType() && V->hasInit()) { 2911 // Add the reference variable to the "trail". 2912 refVars.push_back(DR); 2913 return EvalAddr(V->getInit(), refVars); 2914 } 2915 2916 return NULL; 2917 } 2918 2919 case Stmt::UnaryOperatorClass: { 2920 // The only unary operator that make sense to handle here 2921 // is AddrOf. All others don't make sense as pointers. 2922 UnaryOperator *U = cast<UnaryOperator>(E); 2923 2924 if (U->getOpcode() == UO_AddrOf) 2925 return EvalVal(U->getSubExpr(), refVars); 2926 else 2927 return NULL; 2928 } 2929 2930 case Stmt::BinaryOperatorClass: { 2931 // Handle pointer arithmetic. All other binary operators are not valid 2932 // in this context. 2933 BinaryOperator *B = cast<BinaryOperator>(E); 2934 BinaryOperatorKind op = B->getOpcode(); 2935 2936 if (op != BO_Add && op != BO_Sub) 2937 return NULL; 2938 2939 Expr *Base = B->getLHS(); 2940 2941 // Determine which argument is the real pointer base. It could be 2942 // the RHS argument instead of the LHS. 2943 if (!Base->getType()->isPointerType()) Base = B->getRHS(); 2944 2945 assert (Base->getType()->isPointerType()); 2946 return EvalAddr(Base, refVars); 2947 } 2948 2949 // For conditional operators we need to see if either the LHS or RHS are 2950 // valid DeclRefExpr*s. If one of them is valid, we return it. 2951 case Stmt::ConditionalOperatorClass: { 2952 ConditionalOperator *C = cast<ConditionalOperator>(E); 2953 2954 // Handle the GNU extension for missing LHS. 2955 if (Expr *lhsExpr = C->getLHS()) { 2956 // In C++, we can have a throw-expression, which has 'void' type. 2957 if (!lhsExpr->getType()->isVoidType()) 2958 if (Expr* LHS = EvalAddr(lhsExpr, refVars)) 2959 return LHS; 2960 } 2961 2962 // In C++, we can have a throw-expression, which has 'void' type. 2963 if (C->getRHS()->getType()->isVoidType()) 2964 return NULL; 2965 2966 return EvalAddr(C->getRHS(), refVars); 2967 } 2968 2969 case Stmt::BlockExprClass: 2970 if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures()) 2971 return E; // local block. 2972 return NULL; 2973 2974 case Stmt::AddrLabelExprClass: 2975 return E; // address of label. 2976 2977 case Stmt::ExprWithCleanupsClass: 2978 return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars); 2979 2980 // For casts, we need to handle conversions from arrays to 2981 // pointer values, and pointer-to-pointer conversions. 2982 case Stmt::ImplicitCastExprClass: 2983 case Stmt::CStyleCastExprClass: 2984 case Stmt::CXXFunctionalCastExprClass: 2985 case Stmt::ObjCBridgedCastExprClass: { 2986 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr(); 2987 QualType T = SubExpr->getType(); 2988 2989 if (SubExpr->getType()->isPointerType() || 2990 SubExpr->getType()->isBlockPointerType() || 2991 SubExpr->getType()->isObjCQualifiedIdType()) 2992 return EvalAddr(SubExpr, refVars); 2993 else if (T->isArrayType()) 2994 return EvalVal(SubExpr, refVars); 2995 else 2996 return 0; 2997 } 2998 2999 // C++ casts. For dynamic casts, static casts, and const casts, we 3000 // are always converting from a pointer-to-pointer, so we just blow 3001 // through the cast. In the case the dynamic cast doesn't fail (and 3002 // return NULL), we take the conservative route and report cases 3003 // where we return the address of a stack variable. For Reinterpre 3004 // FIXME: The comment about is wrong; we're not always converting 3005 // from pointer to pointer. I'm guessing that this code should also 3006 // handle references to objects. 3007 case Stmt::CXXStaticCastExprClass: 3008 case Stmt::CXXDynamicCastExprClass: 3009 case Stmt::CXXConstCastExprClass: 3010 case Stmt::CXXReinterpretCastExprClass: { 3011 Expr *S = cast<CXXNamedCastExpr>(E)->getSubExpr(); 3012 if (S->getType()->isPointerType() || S->getType()->isBlockPointerType()) 3013 return EvalAddr(S, refVars); 3014 else 3015 return NULL; 3016 } 3017 3018 case Stmt::MaterializeTemporaryExprClass: 3019 if (Expr *Result = EvalAddr( 3020 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 3021 refVars)) 3022 return Result; 3023 3024 return E; 3025 3026 // Everything else: we simply don't reason about them. 3027 default: 3028 return NULL; 3029 } 3030} 3031 3032 3033/// EvalVal - This function is complements EvalAddr in the mutual recursion. 3034/// See the comments for EvalAddr for more details. 3035static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars) { 3036do { 3037 // We should only be called for evaluating non-pointer expressions, or 3038 // expressions with a pointer type that are not used as references but instead 3039 // are l-values (e.g., DeclRefExpr with a pointer type). 3040 3041 // Our "symbolic interpreter" is just a dispatch off the currently 3042 // viewed AST node. We then recursively traverse the AST by calling 3043 // EvalAddr and EvalVal appropriately. 3044 3045 E = E->IgnoreParens(); 3046 switch (E->getStmtClass()) { 3047 case Stmt::ImplicitCastExprClass: { 3048 ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E); 3049 if (IE->getValueKind() == VK_LValue) { 3050 E = IE->getSubExpr(); 3051 continue; 3052 } 3053 return NULL; 3054 } 3055 3056 case Stmt::ExprWithCleanupsClass: 3057 return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars); 3058 3059 case Stmt::DeclRefExprClass: { 3060 // When we hit a DeclRefExpr we are looking at code that refers to a 3061 // variable's name. If it's not a reference variable we check if it has 3062 // local storage within the function, and if so, return the expression. 3063 DeclRefExpr *DR = cast<DeclRefExpr>(E); 3064 3065 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) 3066 if (V->hasLocalStorage()) { 3067 if (!V->getType()->isReferenceType()) 3068 return DR; 3069 3070 // Reference variable, follow through to the expression that 3071 // it points to. 3072 if (V->hasInit()) { 3073 // Add the reference variable to the "trail". 3074 refVars.push_back(DR); 3075 return EvalVal(V->getInit(), refVars); 3076 } 3077 } 3078 3079 return NULL; 3080 } 3081 3082 case Stmt::UnaryOperatorClass: { 3083 // The only unary operator that make sense to handle here 3084 // is Deref. All others don't resolve to a "name." This includes 3085 // handling all sorts of rvalues passed to a unary operator. 3086 UnaryOperator *U = cast<UnaryOperator>(E); 3087 3088 if (U->getOpcode() == UO_Deref) 3089 return EvalAddr(U->getSubExpr(), refVars); 3090 3091 return NULL; 3092 } 3093 3094 case Stmt::ArraySubscriptExprClass: { 3095 // Array subscripts are potential references to data on the stack. We 3096 // retrieve the DeclRefExpr* for the array variable if it indeed 3097 // has local storage. 3098 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars); 3099 } 3100 3101 case Stmt::ConditionalOperatorClass: { 3102 // For conditional operators we need to see if either the LHS or RHS are 3103 // non-NULL Expr's. If one is non-NULL, we return it. 3104 ConditionalOperator *C = cast<ConditionalOperator>(E); 3105 3106 // Handle the GNU extension for missing LHS. 3107 if (Expr *lhsExpr = C->getLHS()) 3108 if (Expr *LHS = EvalVal(lhsExpr, refVars)) 3109 return LHS; 3110 3111 return EvalVal(C->getRHS(), refVars); 3112 } 3113 3114 // Accesses to members are potential references to data on the stack. 3115 case Stmt::MemberExprClass: { 3116 MemberExpr *M = cast<MemberExpr>(E); 3117 3118 // Check for indirect access. We only want direct field accesses. 3119 if (M->isArrow()) 3120 return NULL; 3121 3122 // Check whether the member type is itself a reference, in which case 3123 // we're not going to refer to the member, but to what the member refers to. 3124 if (M->getMemberDecl()->getType()->isReferenceType()) 3125 return NULL; 3126 3127 return EvalVal(M->getBase(), refVars); 3128 } 3129 3130 case Stmt::MaterializeTemporaryExprClass: 3131 if (Expr *Result = EvalVal( 3132 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 3133 refVars)) 3134 return Result; 3135 3136 return E; 3137 3138 default: 3139 // Check that we don't return or take the address of a reference to a 3140 // temporary. This is only useful in C++. 3141 if (!E->isTypeDependent() && E->isRValue()) 3142 return E; 3143 3144 // Everything else: we simply don't reason about them. 3145 return NULL; 3146 } 3147} while (true); 3148} 3149 3150//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===// 3151 3152/// Check for comparisons of floating point operands using != and ==. 3153/// Issue a warning if these are no self-comparisons, as they are not likely 3154/// to do what the programmer intended. 3155void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) { 3156 bool EmitWarning = true; 3157 3158 Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts(); 3159 Expr* RightExprSansParen = RHS->IgnoreParenImpCasts(); 3160 3161 // Special case: check for x == x (which is OK). 3162 // Do not emit warnings for such cases. 3163 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen)) 3164 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen)) 3165 if (DRL->getDecl() == DRR->getDecl()) 3166 EmitWarning = false; 3167 3168 3169 // Special case: check for comparisons against literals that can be exactly 3170 // represented by APFloat. In such cases, do not emit a warning. This 3171 // is a heuristic: often comparison against such literals are used to 3172 // detect if a value in a variable has not changed. This clearly can 3173 // lead to false negatives. 3174 if (EmitWarning) { 3175 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) { 3176 if (FLL->isExact()) 3177 EmitWarning = false; 3178 } else 3179 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)){ 3180 if (FLR->isExact()) 3181 EmitWarning = false; 3182 } 3183 } 3184 3185 // Check for comparisons with builtin types. 3186 if (EmitWarning) 3187 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen)) 3188 if (CL->isBuiltinCall()) 3189 EmitWarning = false; 3190 3191 if (EmitWarning) 3192 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen)) 3193 if (CR->isBuiltinCall()) 3194 EmitWarning = false; 3195 3196 // Emit the diagnostic. 3197 if (EmitWarning) 3198 Diag(Loc, diag::warn_floatingpoint_eq) 3199 << LHS->getSourceRange() << RHS->getSourceRange(); 3200} 3201 3202//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===// 3203//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===// 3204 3205namespace { 3206 3207/// Structure recording the 'active' range of an integer-valued 3208/// expression. 3209struct IntRange { 3210 /// The number of bits active in the int. 3211 unsigned Width; 3212 3213 /// True if the int is known not to have negative values. 3214 bool NonNegative; 3215 3216 IntRange(unsigned Width, bool NonNegative) 3217 : Width(Width), NonNegative(NonNegative) 3218 {} 3219 3220 /// Returns the range of the bool type. 3221 static IntRange forBoolType() { 3222 return IntRange(1, true); 3223 } 3224 3225 /// Returns the range of an opaque value of the given integral type. 3226 static IntRange forValueOfType(ASTContext &C, QualType T) { 3227 return forValueOfCanonicalType(C, 3228 T->getCanonicalTypeInternal().getTypePtr()); 3229 } 3230 3231 /// Returns the range of an opaque value of a canonical integral type. 3232 static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) { 3233 assert(T->isCanonicalUnqualified()); 3234 3235 if (const VectorType *VT = dyn_cast<VectorType>(T)) 3236 T = VT->getElementType().getTypePtr(); 3237 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 3238 T = CT->getElementType().getTypePtr(); 3239 3240 // For enum types, use the known bit width of the enumerators. 3241 if (const EnumType *ET = dyn_cast<EnumType>(T)) { 3242 EnumDecl *Enum = ET->getDecl(); 3243 if (!Enum->isCompleteDefinition()) 3244 return IntRange(C.getIntWidth(QualType(T, 0)), false); 3245 3246 unsigned NumPositive = Enum->getNumPositiveBits(); 3247 unsigned NumNegative = Enum->getNumNegativeBits(); 3248 3249 return IntRange(std::max(NumPositive, NumNegative), NumNegative == 0); 3250 } 3251 3252 const BuiltinType *BT = cast<BuiltinType>(T); 3253 assert(BT->isInteger()); 3254 3255 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 3256 } 3257 3258 /// Returns the "target" range of a canonical integral type, i.e. 3259 /// the range of values expressible in the type. 3260 /// 3261 /// This matches forValueOfCanonicalType except that enums have the 3262 /// full range of their type, not the range of their enumerators. 3263 static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) { 3264 assert(T->isCanonicalUnqualified()); 3265 3266 if (const VectorType *VT = dyn_cast<VectorType>(T)) 3267 T = VT->getElementType().getTypePtr(); 3268 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 3269 T = CT->getElementType().getTypePtr(); 3270 if (const EnumType *ET = dyn_cast<EnumType>(T)) 3271 T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr(); 3272 3273 const BuiltinType *BT = cast<BuiltinType>(T); 3274 assert(BT->isInteger()); 3275 3276 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 3277 } 3278 3279 /// Returns the supremum of two ranges: i.e. their conservative merge. 3280 static IntRange join(IntRange L, IntRange R) { 3281 return IntRange(std::max(L.Width, R.Width), 3282 L.NonNegative && R.NonNegative); 3283 } 3284 3285 /// Returns the infinum of two ranges: i.e. their aggressive merge. 3286 static IntRange meet(IntRange L, IntRange R) { 3287 return IntRange(std::min(L.Width, R.Width), 3288 L.NonNegative || R.NonNegative); 3289 } 3290}; 3291 3292static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, 3293 unsigned MaxWidth) { 3294 if (value.isSigned() && value.isNegative()) 3295 return IntRange(value.getMinSignedBits(), false); 3296 3297 if (value.getBitWidth() > MaxWidth) 3298 value = value.trunc(MaxWidth); 3299 3300 // isNonNegative() just checks the sign bit without considering 3301 // signedness. 3302 return IntRange(value.getActiveBits(), true); 3303} 3304 3305static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty, 3306 unsigned MaxWidth) { 3307 if (result.isInt()) 3308 return GetValueRange(C, result.getInt(), MaxWidth); 3309 3310 if (result.isVector()) { 3311 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth); 3312 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) { 3313 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth); 3314 R = IntRange::join(R, El); 3315 } 3316 return R; 3317 } 3318 3319 if (result.isComplexInt()) { 3320 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth); 3321 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth); 3322 return IntRange::join(R, I); 3323 } 3324 3325 // This can happen with lossless casts to intptr_t of "based" lvalues. 3326 // Assume it might use arbitrary bits. 3327 // FIXME: The only reason we need to pass the type in here is to get 3328 // the sign right on this one case. It would be nice if APValue 3329 // preserved this. 3330 assert(result.isLValue() || result.isAddrLabelDiff()); 3331 return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType()); 3332} 3333 3334/// Pseudo-evaluate the given integer expression, estimating the 3335/// range of values it might take. 3336/// 3337/// \param MaxWidth - the width to which the value will be truncated 3338static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) { 3339 E = E->IgnoreParens(); 3340 3341 // Try a full evaluation first. 3342 Expr::EvalResult result; 3343 if (E->EvaluateAsRValue(result, C)) 3344 return GetValueRange(C, result.Val, E->getType(), MaxWidth); 3345 3346 // I think we only want to look through implicit casts here; if the 3347 // user has an explicit widening cast, we should treat the value as 3348 // being of the new, wider type. 3349 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) { 3350 if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue) 3351 return GetExprRange(C, CE->getSubExpr(), MaxWidth); 3352 3353 IntRange OutputTypeRange = IntRange::forValueOfType(C, CE->getType()); 3354 3355 bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast); 3356 3357 // Assume that non-integer casts can span the full range of the type. 3358 if (!isIntegerCast) 3359 return OutputTypeRange; 3360 3361 IntRange SubRange 3362 = GetExprRange(C, CE->getSubExpr(), 3363 std::min(MaxWidth, OutputTypeRange.Width)); 3364 3365 // Bail out if the subexpr's range is as wide as the cast type. 3366 if (SubRange.Width >= OutputTypeRange.Width) 3367 return OutputTypeRange; 3368 3369 // Otherwise, we take the smaller width, and we're non-negative if 3370 // either the output type or the subexpr is. 3371 return IntRange(SubRange.Width, 3372 SubRange.NonNegative || OutputTypeRange.NonNegative); 3373 } 3374 3375 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 3376 // If we can fold the condition, just take that operand. 3377 bool CondResult; 3378 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C)) 3379 return GetExprRange(C, CondResult ? CO->getTrueExpr() 3380 : CO->getFalseExpr(), 3381 MaxWidth); 3382 3383 // Otherwise, conservatively merge. 3384 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth); 3385 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth); 3386 return IntRange::join(L, R); 3387 } 3388 3389 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 3390 switch (BO->getOpcode()) { 3391 3392 // Boolean-valued operations are single-bit and positive. 3393 case BO_LAnd: 3394 case BO_LOr: 3395 case BO_LT: 3396 case BO_GT: 3397 case BO_LE: 3398 case BO_GE: 3399 case BO_EQ: 3400 case BO_NE: 3401 return IntRange::forBoolType(); 3402 3403 // The type of the assignments is the type of the LHS, so the RHS 3404 // is not necessarily the same type. 3405 case BO_MulAssign: 3406 case BO_DivAssign: 3407 case BO_RemAssign: 3408 case BO_AddAssign: 3409 case BO_SubAssign: 3410 case BO_XorAssign: 3411 case BO_OrAssign: 3412 // TODO: bitfields? 3413 return IntRange::forValueOfType(C, E->getType()); 3414 3415 // Simple assignments just pass through the RHS, which will have 3416 // been coerced to the LHS type. 3417 case BO_Assign: 3418 // TODO: bitfields? 3419 return GetExprRange(C, BO->getRHS(), MaxWidth); 3420 3421 // Operations with opaque sources are black-listed. 3422 case BO_PtrMemD: 3423 case BO_PtrMemI: 3424 return IntRange::forValueOfType(C, E->getType()); 3425 3426 // Bitwise-and uses the *infinum* of the two source ranges. 3427 case BO_And: 3428 case BO_AndAssign: 3429 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth), 3430 GetExprRange(C, BO->getRHS(), MaxWidth)); 3431 3432 // Left shift gets black-listed based on a judgement call. 3433 case BO_Shl: 3434 // ...except that we want to treat '1 << (blah)' as logically 3435 // positive. It's an important idiom. 3436 if (IntegerLiteral *I 3437 = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) { 3438 if (I->getValue() == 1) { 3439 IntRange R = IntRange::forValueOfType(C, E->getType()); 3440 return IntRange(R.Width, /*NonNegative*/ true); 3441 } 3442 } 3443 // fallthrough 3444 3445 case BO_ShlAssign: 3446 return IntRange::forValueOfType(C, E->getType()); 3447 3448 // Right shift by a constant can narrow its left argument. 3449 case BO_Shr: 3450 case BO_ShrAssign: { 3451 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 3452 3453 // If the shift amount is a positive constant, drop the width by 3454 // that much. 3455 llvm::APSInt shift; 3456 if (BO->getRHS()->isIntegerConstantExpr(shift, C) && 3457 shift.isNonNegative()) { 3458 unsigned zext = shift.getZExtValue(); 3459 if (zext >= L.Width) 3460 L.Width = (L.NonNegative ? 0 : 1); 3461 else 3462 L.Width -= zext; 3463 } 3464 3465 return L; 3466 } 3467 3468 // Comma acts as its right operand. 3469 case BO_Comma: 3470 return GetExprRange(C, BO->getRHS(), MaxWidth); 3471 3472 // Black-list pointer subtractions. 3473 case BO_Sub: 3474 if (BO->getLHS()->getType()->isPointerType()) 3475 return IntRange::forValueOfType(C, E->getType()); 3476 break; 3477 3478 // The width of a division result is mostly determined by the size 3479 // of the LHS. 3480 case BO_Div: { 3481 // Don't 'pre-truncate' the operands. 3482 unsigned opWidth = C.getIntWidth(E->getType()); 3483 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 3484 3485 // If the divisor is constant, use that. 3486 llvm::APSInt divisor; 3487 if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) { 3488 unsigned log2 = divisor.logBase2(); // floor(log_2(divisor)) 3489 if (log2 >= L.Width) 3490 L.Width = (L.NonNegative ? 0 : 1); 3491 else 3492 L.Width = std::min(L.Width - log2, MaxWidth); 3493 return L; 3494 } 3495 3496 // Otherwise, just use the LHS's width. 3497 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 3498 return IntRange(L.Width, L.NonNegative && R.NonNegative); 3499 } 3500 3501 // The result of a remainder can't be larger than the result of 3502 // either side. 3503 case BO_Rem: { 3504 // Don't 'pre-truncate' the operands. 3505 unsigned opWidth = C.getIntWidth(E->getType()); 3506 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 3507 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 3508 3509 IntRange meet = IntRange::meet(L, R); 3510 meet.Width = std::min(meet.Width, MaxWidth); 3511 return meet; 3512 } 3513 3514 // The default behavior is okay for these. 3515 case BO_Mul: 3516 case BO_Add: 3517 case BO_Xor: 3518 case BO_Or: 3519 break; 3520 } 3521 3522 // The default case is to treat the operation as if it were closed 3523 // on the narrowest type that encompasses both operands. 3524 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 3525 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth); 3526 return IntRange::join(L, R); 3527 } 3528 3529 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 3530 switch (UO->getOpcode()) { 3531 // Boolean-valued operations are white-listed. 3532 case UO_LNot: 3533 return IntRange::forBoolType(); 3534 3535 // Operations with opaque sources are black-listed. 3536 case UO_Deref: 3537 case UO_AddrOf: // should be impossible 3538 return IntRange::forValueOfType(C, E->getType()); 3539 3540 default: 3541 return GetExprRange(C, UO->getSubExpr(), MaxWidth); 3542 } 3543 } 3544 3545 if (dyn_cast<OffsetOfExpr>(E)) { 3546 IntRange::forValueOfType(C, E->getType()); 3547 } 3548 3549 if (FieldDecl *BitField = E->getBitField()) 3550 return IntRange(BitField->getBitWidthValue(C), 3551 BitField->getType()->isUnsignedIntegerOrEnumerationType()); 3552 3553 return IntRange::forValueOfType(C, E->getType()); 3554} 3555 3556static IntRange GetExprRange(ASTContext &C, Expr *E) { 3557 return GetExprRange(C, E, C.getIntWidth(E->getType())); 3558} 3559 3560/// Checks whether the given value, which currently has the given 3561/// source semantics, has the same value when coerced through the 3562/// target semantics. 3563static bool IsSameFloatAfterCast(const llvm::APFloat &value, 3564 const llvm::fltSemantics &Src, 3565 const llvm::fltSemantics &Tgt) { 3566 llvm::APFloat truncated = value; 3567 3568 bool ignored; 3569 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored); 3570 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored); 3571 3572 return truncated.bitwiseIsEqual(value); 3573} 3574 3575/// Checks whether the given value, which currently has the given 3576/// source semantics, has the same value when coerced through the 3577/// target semantics. 3578/// 3579/// The value might be a vector of floats (or a complex number). 3580static bool IsSameFloatAfterCast(const APValue &value, 3581 const llvm::fltSemantics &Src, 3582 const llvm::fltSemantics &Tgt) { 3583 if (value.isFloat()) 3584 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt); 3585 3586 if (value.isVector()) { 3587 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i) 3588 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt)) 3589 return false; 3590 return true; 3591 } 3592 3593 assert(value.isComplexFloat()); 3594 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) && 3595 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt)); 3596} 3597 3598static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC); 3599 3600static bool IsZero(Sema &S, Expr *E) { 3601 // Suppress cases where we are comparing against an enum constant. 3602 if (const DeclRefExpr *DR = 3603 dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts())) 3604 if (isa<EnumConstantDecl>(DR->getDecl())) 3605 return false; 3606 3607 // Suppress cases where the '0' value is expanded from a macro. 3608 if (E->getLocStart().isMacroID()) 3609 return false; 3610 3611 llvm::APSInt Value; 3612 return E->isIntegerConstantExpr(Value, S.Context) && Value == 0; 3613} 3614 3615static bool HasEnumType(Expr *E) { 3616 // Strip off implicit integral promotions. 3617 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 3618 if (ICE->getCastKind() != CK_IntegralCast && 3619 ICE->getCastKind() != CK_NoOp) 3620 break; 3621 E = ICE->getSubExpr(); 3622 } 3623 3624 return E->getType()->isEnumeralType(); 3625} 3626 3627static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) { 3628 BinaryOperatorKind op = E->getOpcode(); 3629 if (E->isValueDependent()) 3630 return; 3631 3632 if (op == BO_LT && IsZero(S, E->getRHS())) { 3633 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 3634 << "< 0" << "false" << HasEnumType(E->getLHS()) 3635 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 3636 } else if (op == BO_GE && IsZero(S, E->getRHS())) { 3637 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 3638 << ">= 0" << "true" << HasEnumType(E->getLHS()) 3639 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 3640 } else if (op == BO_GT && IsZero(S, E->getLHS())) { 3641 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 3642 << "0 >" << "false" << HasEnumType(E->getRHS()) 3643 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 3644 } else if (op == BO_LE && IsZero(S, E->getLHS())) { 3645 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 3646 << "0 <=" << "true" << HasEnumType(E->getRHS()) 3647 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 3648 } 3649} 3650 3651/// Analyze the operands of the given comparison. Implements the 3652/// fallback case from AnalyzeComparison. 3653static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) { 3654 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 3655 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 3656} 3657 3658/// \brief Implements -Wsign-compare. 3659/// 3660/// \param E the binary operator to check for warnings 3661static void AnalyzeComparison(Sema &S, BinaryOperator *E) { 3662 // The type the comparison is being performed in. 3663 QualType T = E->getLHS()->getType(); 3664 assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType()) 3665 && "comparison with mismatched types"); 3666 3667 // We don't do anything special if this isn't an unsigned integral 3668 // comparison: we're only interested in integral comparisons, and 3669 // signed comparisons only happen in cases we don't care to warn about. 3670 // 3671 // We also don't care about value-dependent expressions or expressions 3672 // whose result is a constant. 3673 if (!T->hasUnsignedIntegerRepresentation() 3674 || E->isValueDependent() || E->isIntegerConstantExpr(S.Context)) 3675 return AnalyzeImpConvsInComparison(S, E); 3676 3677 Expr *LHS = E->getLHS()->IgnoreParenImpCasts(); 3678 Expr *RHS = E->getRHS()->IgnoreParenImpCasts(); 3679 3680 // Check to see if one of the (unmodified) operands is of different 3681 // signedness. 3682 Expr *signedOperand, *unsignedOperand; 3683 if (LHS->getType()->hasSignedIntegerRepresentation()) { 3684 assert(!RHS->getType()->hasSignedIntegerRepresentation() && 3685 "unsigned comparison between two signed integer expressions?"); 3686 signedOperand = LHS; 3687 unsignedOperand = RHS; 3688 } else if (RHS->getType()->hasSignedIntegerRepresentation()) { 3689 signedOperand = RHS; 3690 unsignedOperand = LHS; 3691 } else { 3692 CheckTrivialUnsignedComparison(S, E); 3693 return AnalyzeImpConvsInComparison(S, E); 3694 } 3695 3696 // Otherwise, calculate the effective range of the signed operand. 3697 IntRange signedRange = GetExprRange(S.Context, signedOperand); 3698 3699 // Go ahead and analyze implicit conversions in the operands. Note 3700 // that we skip the implicit conversions on both sides. 3701 AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc()); 3702 AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc()); 3703 3704 // If the signed range is non-negative, -Wsign-compare won't fire, 3705 // but we should still check for comparisons which are always true 3706 // or false. 3707 if (signedRange.NonNegative) 3708 return CheckTrivialUnsignedComparison(S, E); 3709 3710 // For (in)equality comparisons, if the unsigned operand is a 3711 // constant which cannot collide with a overflowed signed operand, 3712 // then reinterpreting the signed operand as unsigned will not 3713 // change the result of the comparison. 3714 if (E->isEqualityOp()) { 3715 unsigned comparisonWidth = S.Context.getIntWidth(T); 3716 IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand); 3717 3718 // We should never be unable to prove that the unsigned operand is 3719 // non-negative. 3720 assert(unsignedRange.NonNegative && "unsigned range includes negative?"); 3721 3722 if (unsignedRange.Width < comparisonWidth) 3723 return; 3724 } 3725 3726 S.Diag(E->getOperatorLoc(), diag::warn_mixed_sign_comparison) 3727 << LHS->getType() << RHS->getType() 3728 << LHS->getSourceRange() << RHS->getSourceRange(); 3729} 3730 3731/// Analyzes an attempt to assign the given value to a bitfield. 3732/// 3733/// Returns true if there was something fishy about the attempt. 3734static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init, 3735 SourceLocation InitLoc) { 3736 assert(Bitfield->isBitField()); 3737 if (Bitfield->isInvalidDecl()) 3738 return false; 3739 3740 // White-list bool bitfields. 3741 if (Bitfield->getType()->isBooleanType()) 3742 return false; 3743 3744 // Ignore value- or type-dependent expressions. 3745 if (Bitfield->getBitWidth()->isValueDependent() || 3746 Bitfield->getBitWidth()->isTypeDependent() || 3747 Init->isValueDependent() || 3748 Init->isTypeDependent()) 3749 return false; 3750 3751 Expr *OriginalInit = Init->IgnoreParenImpCasts(); 3752 3753 llvm::APSInt Value; 3754 if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects)) 3755 return false; 3756 3757 unsigned OriginalWidth = Value.getBitWidth(); 3758 unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context); 3759 3760 if (OriginalWidth <= FieldWidth) 3761 return false; 3762 3763 // Compute the value which the bitfield will contain. 3764 llvm::APSInt TruncatedValue = Value.trunc(FieldWidth); 3765 TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType()); 3766 3767 // Check whether the stored value is equal to the original value. 3768 TruncatedValue = TruncatedValue.extend(OriginalWidth); 3769 if (Value == TruncatedValue) 3770 return false; 3771 3772 // Special-case bitfields of width 1: booleans are naturally 0/1, and 3773 // therefore don't strictly fit into a signed bitfield of width 1. 3774 if (FieldWidth == 1 && Value == 1) 3775 return false; 3776 3777 std::string PrettyValue = Value.toString(10); 3778 std::string PrettyTrunc = TruncatedValue.toString(10); 3779 3780 S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant) 3781 << PrettyValue << PrettyTrunc << OriginalInit->getType() 3782 << Init->getSourceRange(); 3783 3784 return true; 3785} 3786 3787/// Analyze the given simple or compound assignment for warning-worthy 3788/// operations. 3789static void AnalyzeAssignment(Sema &S, BinaryOperator *E) { 3790 // Just recurse on the LHS. 3791 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 3792 3793 // We want to recurse on the RHS as normal unless we're assigning to 3794 // a bitfield. 3795 if (FieldDecl *Bitfield = E->getLHS()->getBitField()) { 3796 if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(), 3797 E->getOperatorLoc())) { 3798 // Recurse, ignoring any implicit conversions on the RHS. 3799 return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(), 3800 E->getOperatorLoc()); 3801 } 3802 } 3803 3804 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 3805} 3806 3807/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 3808static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T, 3809 SourceLocation CContext, unsigned diag, 3810 bool pruneControlFlow = false) { 3811 if (pruneControlFlow) { 3812 S.DiagRuntimeBehavior(E->getExprLoc(), E, 3813 S.PDiag(diag) 3814 << SourceType << T << E->getSourceRange() 3815 << SourceRange(CContext)); 3816 return; 3817 } 3818 S.Diag(E->getExprLoc(), diag) 3819 << SourceType << T << E->getSourceRange() << SourceRange(CContext); 3820} 3821 3822/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 3823static void DiagnoseImpCast(Sema &S, Expr *E, QualType T, 3824 SourceLocation CContext, unsigned diag, 3825 bool pruneControlFlow = false) { 3826 DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow); 3827} 3828 3829/// Diagnose an implicit cast from a literal expression. Does not warn when the 3830/// cast wouldn't lose information. 3831void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T, 3832 SourceLocation CContext) { 3833 // Try to convert the literal exactly to an integer. If we can, don't warn. 3834 bool isExact = false; 3835 const llvm::APFloat &Value = FL->getValue(); 3836 llvm::APSInt IntegerValue(S.Context.getIntWidth(T), 3837 T->hasUnsignedIntegerRepresentation()); 3838 if (Value.convertToInteger(IntegerValue, 3839 llvm::APFloat::rmTowardZero, &isExact) 3840 == llvm::APFloat::opOK && isExact) 3841 return; 3842 3843 S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer) 3844 << FL->getType() << T << FL->getSourceRange() << SourceRange(CContext); 3845} 3846 3847std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) { 3848 if (!Range.Width) return "0"; 3849 3850 llvm::APSInt ValueInRange = Value; 3851 ValueInRange.setIsSigned(!Range.NonNegative); 3852 ValueInRange = ValueInRange.trunc(Range.Width); 3853 return ValueInRange.toString(10); 3854} 3855 3856void CheckImplicitConversion(Sema &S, Expr *E, QualType T, 3857 SourceLocation CC, bool *ICContext = 0) { 3858 if (E->isTypeDependent() || E->isValueDependent()) return; 3859 3860 const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr(); 3861 const Type *Target = S.Context.getCanonicalType(T).getTypePtr(); 3862 if (Source == Target) return; 3863 if (Target->isDependentType()) return; 3864 3865 // If the conversion context location is invalid don't complain. We also 3866 // don't want to emit a warning if the issue occurs from the expansion of 3867 // a system macro. The problem is that 'getSpellingLoc()' is slow, so we 3868 // delay this check as long as possible. Once we detect we are in that 3869 // scenario, we just return. 3870 if (CC.isInvalid()) 3871 return; 3872 3873 // Diagnose implicit casts to bool. 3874 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) { 3875 if (isa<StringLiteral>(E)) 3876 // Warn on string literal to bool. Checks for string literals in logical 3877 // expressions, for instances, assert(0 && "error here"), is prevented 3878 // by a check in AnalyzeImplicitConversions(). 3879 return DiagnoseImpCast(S, E, T, CC, 3880 diag::warn_impcast_string_literal_to_bool); 3881 if (Source->isFunctionType()) { 3882 // Warn on function to bool. Checks free functions and static member 3883 // functions. Weakly imported functions are excluded from the check, 3884 // since it's common to test their value to check whether the linker 3885 // found a definition for them. 3886 ValueDecl *D = 0; 3887 if (DeclRefExpr* R = dyn_cast<DeclRefExpr>(E)) { 3888 D = R->getDecl(); 3889 } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) { 3890 D = M->getMemberDecl(); 3891 } 3892 3893 if (D && !D->isWeak()) { 3894 if (FunctionDecl* F = dyn_cast<FunctionDecl>(D)) { 3895 S.Diag(E->getExprLoc(), diag::warn_impcast_function_to_bool) 3896 << F << E->getSourceRange() << SourceRange(CC); 3897 S.Diag(E->getExprLoc(), diag::note_function_to_bool_silence) 3898 << FixItHint::CreateInsertion(E->getExprLoc(), "&"); 3899 QualType ReturnType; 3900 UnresolvedSet<4> NonTemplateOverloads; 3901 S.isExprCallable(*E, ReturnType, NonTemplateOverloads); 3902 if (!ReturnType.isNull() 3903 && ReturnType->isSpecificBuiltinType(BuiltinType::Bool)) 3904 S.Diag(E->getExprLoc(), diag::note_function_to_bool_call) 3905 << FixItHint::CreateInsertion( 3906 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()), "()"); 3907 return; 3908 } 3909 } 3910 } 3911 return; // Other casts to bool are not checked. 3912 } 3913 3914 // Strip vector types. 3915 if (isa<VectorType>(Source)) { 3916 if (!isa<VectorType>(Target)) { 3917 if (S.SourceMgr.isInSystemMacro(CC)) 3918 return; 3919 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar); 3920 } 3921 3922 // If the vector cast is cast between two vectors of the same size, it is 3923 // a bitcast, not a conversion. 3924 if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target)) 3925 return; 3926 3927 Source = cast<VectorType>(Source)->getElementType().getTypePtr(); 3928 Target = cast<VectorType>(Target)->getElementType().getTypePtr(); 3929 } 3930 3931 // Strip complex types. 3932 if (isa<ComplexType>(Source)) { 3933 if (!isa<ComplexType>(Target)) { 3934 if (S.SourceMgr.isInSystemMacro(CC)) 3935 return; 3936 3937 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar); 3938 } 3939 3940 Source = cast<ComplexType>(Source)->getElementType().getTypePtr(); 3941 Target = cast<ComplexType>(Target)->getElementType().getTypePtr(); 3942 } 3943 3944 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source); 3945 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target); 3946 3947 // If the source is floating point... 3948 if (SourceBT && SourceBT->isFloatingPoint()) { 3949 // ...and the target is floating point... 3950 if (TargetBT && TargetBT->isFloatingPoint()) { 3951 // ...then warn if we're dropping FP rank. 3952 3953 // Builtin FP kinds are ordered by increasing FP rank. 3954 if (SourceBT->getKind() > TargetBT->getKind()) { 3955 // Don't warn about float constants that are precisely 3956 // representable in the target type. 3957 Expr::EvalResult result; 3958 if (E->EvaluateAsRValue(result, S.Context)) { 3959 // Value might be a float, a float vector, or a float complex. 3960 if (IsSameFloatAfterCast(result.Val, 3961 S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)), 3962 S.Context.getFloatTypeSemantics(QualType(SourceBT, 0)))) 3963 return; 3964 } 3965 3966 if (S.SourceMgr.isInSystemMacro(CC)) 3967 return; 3968 3969 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision); 3970 } 3971 return; 3972 } 3973 3974 // If the target is integral, always warn. 3975 if ((TargetBT && TargetBT->isInteger())) { 3976 if (S.SourceMgr.isInSystemMacro(CC)) 3977 return; 3978 3979 Expr *InnerE = E->IgnoreParenImpCasts(); 3980 // We also want to warn on, e.g., "int i = -1.234" 3981 if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE)) 3982 if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus) 3983 InnerE = UOp->getSubExpr()->IgnoreParenImpCasts(); 3984 3985 if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) { 3986 DiagnoseFloatingLiteralImpCast(S, FL, T, CC); 3987 } else { 3988 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer); 3989 } 3990 } 3991 3992 return; 3993 } 3994 3995 if (!Source->isIntegerType() || !Target->isIntegerType()) 3996 return; 3997 3998 if ((E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull) 3999 == Expr::NPCK_GNUNull) && Target->isIntegerType()) { 4000 S.Diag(E->getExprLoc(), diag::warn_impcast_null_pointer_to_integer) 4001 << E->getSourceRange() << clang::SourceRange(CC); 4002 return; 4003 } 4004 4005 IntRange SourceRange = GetExprRange(S.Context, E); 4006 IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target); 4007 4008 if (SourceRange.Width > TargetRange.Width) { 4009 // If the source is a constant, use a default-on diagnostic. 4010 // TODO: this should happen for bitfield stores, too. 4011 llvm::APSInt Value(32); 4012 if (E->isIntegerConstantExpr(Value, S.Context)) { 4013 if (S.SourceMgr.isInSystemMacro(CC)) 4014 return; 4015 4016 std::string PrettySourceValue = Value.toString(10); 4017 std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange); 4018 4019 S.DiagRuntimeBehavior(E->getExprLoc(), E, 4020 S.PDiag(diag::warn_impcast_integer_precision_constant) 4021 << PrettySourceValue << PrettyTargetValue 4022 << E->getType() << T << E->getSourceRange() 4023 << clang::SourceRange(CC)); 4024 return; 4025 } 4026 4027 // People want to build with -Wshorten-64-to-32 and not -Wconversion. 4028 if (S.SourceMgr.isInSystemMacro(CC)) 4029 return; 4030 4031 if (SourceRange.Width == 64 && TargetRange.Width == 32) 4032 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32, 4033 /* pruneControlFlow */ true); 4034 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision); 4035 } 4036 4037 if ((TargetRange.NonNegative && !SourceRange.NonNegative) || 4038 (!TargetRange.NonNegative && SourceRange.NonNegative && 4039 SourceRange.Width == TargetRange.Width)) { 4040 4041 if (S.SourceMgr.isInSystemMacro(CC)) 4042 return; 4043 4044 unsigned DiagID = diag::warn_impcast_integer_sign; 4045 4046 // Traditionally, gcc has warned about this under -Wsign-compare. 4047 // We also want to warn about it in -Wconversion. 4048 // So if -Wconversion is off, use a completely identical diagnostic 4049 // in the sign-compare group. 4050 // The conditional-checking code will 4051 if (ICContext) { 4052 DiagID = diag::warn_impcast_integer_sign_conditional; 4053 *ICContext = true; 4054 } 4055 4056 return DiagnoseImpCast(S, E, T, CC, DiagID); 4057 } 4058 4059 // Diagnose conversions between different enumeration types. 4060 // In C, we pretend that the type of an EnumConstantDecl is its enumeration 4061 // type, to give us better diagnostics. 4062 QualType SourceType = E->getType(); 4063 if (!S.getLangOptions().CPlusPlus) { 4064 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 4065 if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) { 4066 EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext()); 4067 SourceType = S.Context.getTypeDeclType(Enum); 4068 Source = S.Context.getCanonicalType(SourceType).getTypePtr(); 4069 } 4070 } 4071 4072 if (const EnumType *SourceEnum = Source->getAs<EnumType>()) 4073 if (const EnumType *TargetEnum = Target->getAs<EnumType>()) 4074 if ((SourceEnum->getDecl()->getIdentifier() || 4075 SourceEnum->getDecl()->getTypedefNameForAnonDecl()) && 4076 (TargetEnum->getDecl()->getIdentifier() || 4077 TargetEnum->getDecl()->getTypedefNameForAnonDecl()) && 4078 SourceEnum != TargetEnum) { 4079 if (S.SourceMgr.isInSystemMacro(CC)) 4080 return; 4081 4082 return DiagnoseImpCast(S, E, SourceType, T, CC, 4083 diag::warn_impcast_different_enum_types); 4084 } 4085 4086 return; 4087} 4088 4089void CheckConditionalOperator(Sema &S, ConditionalOperator *E, QualType T); 4090 4091void CheckConditionalOperand(Sema &S, Expr *E, QualType T, 4092 SourceLocation CC, bool &ICContext) { 4093 E = E->IgnoreParenImpCasts(); 4094 4095 if (isa<ConditionalOperator>(E)) 4096 return CheckConditionalOperator(S, cast<ConditionalOperator>(E), T); 4097 4098 AnalyzeImplicitConversions(S, E, CC); 4099 if (E->getType() != T) 4100 return CheckImplicitConversion(S, E, T, CC, &ICContext); 4101 return; 4102} 4103 4104void CheckConditionalOperator(Sema &S, ConditionalOperator *E, QualType T) { 4105 SourceLocation CC = E->getQuestionLoc(); 4106 4107 AnalyzeImplicitConversions(S, E->getCond(), CC); 4108 4109 bool Suspicious = false; 4110 CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious); 4111 CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious); 4112 4113 // If -Wconversion would have warned about either of the candidates 4114 // for a signedness conversion to the context type... 4115 if (!Suspicious) return; 4116 4117 // ...but it's currently ignored... 4118 if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional, 4119 CC)) 4120 return; 4121 4122 // ...then check whether it would have warned about either of the 4123 // candidates for a signedness conversion to the condition type. 4124 if (E->getType() == T) return; 4125 4126 Suspicious = false; 4127 CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(), 4128 E->getType(), CC, &Suspicious); 4129 if (!Suspicious) 4130 CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(), 4131 E->getType(), CC, &Suspicious); 4132} 4133 4134/// AnalyzeImplicitConversions - Find and report any interesting 4135/// implicit conversions in the given expression. There are a couple 4136/// of competing diagnostics here, -Wconversion and -Wsign-compare. 4137void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) { 4138 QualType T = OrigE->getType(); 4139 Expr *E = OrigE->IgnoreParenImpCasts(); 4140 4141 if (E->isTypeDependent() || E->isValueDependent()) 4142 return; 4143 4144 // For conditional operators, we analyze the arguments as if they 4145 // were being fed directly into the output. 4146 if (isa<ConditionalOperator>(E)) { 4147 ConditionalOperator *CO = cast<ConditionalOperator>(E); 4148 CheckConditionalOperator(S, CO, T); 4149 return; 4150 } 4151 4152 // Go ahead and check any implicit conversions we might have skipped. 4153 // The non-canonical typecheck is just an optimization; 4154 // CheckImplicitConversion will filter out dead implicit conversions. 4155 if (E->getType() != T) 4156 CheckImplicitConversion(S, E, T, CC); 4157 4158 // Now continue drilling into this expression. 4159 4160 // Skip past explicit casts. 4161 if (isa<ExplicitCastExpr>(E)) { 4162 E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts(); 4163 return AnalyzeImplicitConversions(S, E, CC); 4164 } 4165 4166 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 4167 // Do a somewhat different check with comparison operators. 4168 if (BO->isComparisonOp()) 4169 return AnalyzeComparison(S, BO); 4170 4171 // And with simple assignments. 4172 if (BO->getOpcode() == BO_Assign) 4173 return AnalyzeAssignment(S, BO); 4174 } 4175 4176 // These break the otherwise-useful invariant below. Fortunately, 4177 // we don't really need to recurse into them, because any internal 4178 // expressions should have been analyzed already when they were 4179 // built into statements. 4180 if (isa<StmtExpr>(E)) return; 4181 4182 // Don't descend into unevaluated contexts. 4183 if (isa<UnaryExprOrTypeTraitExpr>(E)) return; 4184 4185 // Now just recurse over the expression's children. 4186 CC = E->getExprLoc(); 4187 BinaryOperator *BO = dyn_cast<BinaryOperator>(E); 4188 bool IsLogicalOperator = BO && BO->isLogicalOp(); 4189 for (Stmt::child_range I = E->children(); I; ++I) { 4190 Expr *ChildExpr = dyn_cast_or_null<Expr>(*I); 4191 if (!ChildExpr) 4192 continue; 4193 4194 if (IsLogicalOperator && 4195 isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts())) 4196 // Ignore checking string literals that are in logical operators. 4197 continue; 4198 AnalyzeImplicitConversions(S, ChildExpr, CC); 4199 } 4200} 4201 4202} // end anonymous namespace 4203 4204/// Diagnoses "dangerous" implicit conversions within the given 4205/// expression (which is a full expression). Implements -Wconversion 4206/// and -Wsign-compare. 4207/// 4208/// \param CC the "context" location of the implicit conversion, i.e. 4209/// the most location of the syntactic entity requiring the implicit 4210/// conversion 4211void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) { 4212 // Don't diagnose in unevaluated contexts. 4213 if (ExprEvalContexts.back().Context == Sema::Unevaluated) 4214 return; 4215 4216 // Don't diagnose for value- or type-dependent expressions. 4217 if (E->isTypeDependent() || E->isValueDependent()) 4218 return; 4219 4220 // Check for array bounds violations in cases where the check isn't triggered 4221 // elsewhere for other Expr types (like BinaryOperators), e.g. when an 4222 // ArraySubscriptExpr is on the RHS of a variable initialization. 4223 CheckArrayAccess(E); 4224 4225 // This is not the right CC for (e.g.) a variable initialization. 4226 AnalyzeImplicitConversions(*this, E, CC); 4227} 4228 4229void Sema::CheckBitFieldInitialization(SourceLocation InitLoc, 4230 FieldDecl *BitField, 4231 Expr *Init) { 4232 (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc); 4233} 4234 4235/// CheckParmsForFunctionDef - Check that the parameters of the given 4236/// function are appropriate for the definition of a function. This 4237/// takes care of any checks that cannot be performed on the 4238/// declaration itself, e.g., that the types of each of the function 4239/// parameters are complete. 4240bool Sema::CheckParmsForFunctionDef(ParmVarDecl **P, ParmVarDecl **PEnd, 4241 bool CheckParameterNames) { 4242 bool HasInvalidParm = false; 4243 for (; P != PEnd; ++P) { 4244 ParmVarDecl *Param = *P; 4245 4246 // C99 6.7.5.3p4: the parameters in a parameter type list in a 4247 // function declarator that is part of a function definition of 4248 // that function shall not have incomplete type. 4249 // 4250 // This is also C++ [dcl.fct]p6. 4251 if (!Param->isInvalidDecl() && 4252 RequireCompleteType(Param->getLocation(), Param->getType(), 4253 diag::err_typecheck_decl_incomplete_type)) { 4254 Param->setInvalidDecl(); 4255 HasInvalidParm = true; 4256 } 4257 4258 // C99 6.9.1p5: If the declarator includes a parameter type list, the 4259 // declaration of each parameter shall include an identifier. 4260 if (CheckParameterNames && 4261 Param->getIdentifier() == 0 && 4262 !Param->isImplicit() && 4263 !getLangOptions().CPlusPlus) 4264 Diag(Param->getLocation(), diag::err_parameter_name_omitted); 4265 4266 // C99 6.7.5.3p12: 4267 // If the function declarator is not part of a definition of that 4268 // function, parameters may have incomplete type and may use the [*] 4269 // notation in their sequences of declarator specifiers to specify 4270 // variable length array types. 4271 QualType PType = Param->getOriginalType(); 4272 if (const ArrayType *AT = Context.getAsArrayType(PType)) { 4273 if (AT->getSizeModifier() == ArrayType::Star) { 4274 // FIXME: This diagnosic should point the the '[*]' if source-location 4275 // information is added for it. 4276 Diag(Param->getLocation(), diag::err_array_star_in_function_definition); 4277 } 4278 } 4279 } 4280 4281 return HasInvalidParm; 4282} 4283 4284/// CheckCastAlign - Implements -Wcast-align, which warns when a 4285/// pointer cast increases the alignment requirements. 4286void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) { 4287 // This is actually a lot of work to potentially be doing on every 4288 // cast; don't do it if we're ignoring -Wcast_align (as is the default). 4289 if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align, 4290 TRange.getBegin()) 4291 == DiagnosticsEngine::Ignored) 4292 return; 4293 4294 // Ignore dependent types. 4295 if (T->isDependentType() || Op->getType()->isDependentType()) 4296 return; 4297 4298 // Require that the destination be a pointer type. 4299 const PointerType *DestPtr = T->getAs<PointerType>(); 4300 if (!DestPtr) return; 4301 4302 // If the destination has alignment 1, we're done. 4303 QualType DestPointee = DestPtr->getPointeeType(); 4304 if (DestPointee->isIncompleteType()) return; 4305 CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee); 4306 if (DestAlign.isOne()) return; 4307 4308 // Require that the source be a pointer type. 4309 const PointerType *SrcPtr = Op->getType()->getAs<PointerType>(); 4310 if (!SrcPtr) return; 4311 QualType SrcPointee = SrcPtr->getPointeeType(); 4312 4313 // Whitelist casts from cv void*. We already implicitly 4314 // whitelisted casts to cv void*, since they have alignment 1. 4315 // Also whitelist casts involving incomplete types, which implicitly 4316 // includes 'void'. 4317 if (SrcPointee->isIncompleteType()) return; 4318 4319 CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee); 4320 if (SrcAlign >= DestAlign) return; 4321 4322 Diag(TRange.getBegin(), diag::warn_cast_align) 4323 << Op->getType() << T 4324 << static_cast<unsigned>(SrcAlign.getQuantity()) 4325 << static_cast<unsigned>(DestAlign.getQuantity()) 4326 << TRange << Op->getSourceRange(); 4327} 4328 4329static const Type* getElementType(const Expr *BaseExpr) { 4330 const Type* EltType = BaseExpr->getType().getTypePtr(); 4331 if (EltType->isAnyPointerType()) 4332 return EltType->getPointeeType().getTypePtr(); 4333 else if (EltType->isArrayType()) 4334 return EltType->getBaseElementTypeUnsafe(); 4335 return EltType; 4336} 4337 4338/// \brief Check whether this array fits the idiom of a size-one tail padded 4339/// array member of a struct. 4340/// 4341/// We avoid emitting out-of-bounds access warnings for such arrays as they are 4342/// commonly used to emulate flexible arrays in C89 code. 4343static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size, 4344 const NamedDecl *ND) { 4345 if (Size != 1 || !ND) return false; 4346 4347 const FieldDecl *FD = dyn_cast<FieldDecl>(ND); 4348 if (!FD) return false; 4349 4350 // Don't consider sizes resulting from macro expansions or template argument 4351 // substitution to form C89 tail-padded arrays. 4352 ConstantArrayTypeLoc TL = 4353 cast<ConstantArrayTypeLoc>(FD->getTypeSourceInfo()->getTypeLoc()); 4354 const Expr *SizeExpr = dyn_cast<IntegerLiteral>(TL.getSizeExpr()); 4355 if (!SizeExpr || SizeExpr->getExprLoc().isMacroID()) 4356 return false; 4357 4358 const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext()); 4359 if (!RD) return false; 4360 if (RD->isUnion()) return false; 4361 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) { 4362 if (!CRD->isStandardLayout()) return false; 4363 } 4364 4365 // See if this is the last field decl in the record. 4366 const Decl *D = FD; 4367 while ((D = D->getNextDeclInContext())) 4368 if (isa<FieldDecl>(D)) 4369 return false; 4370 return true; 4371} 4372 4373void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr, 4374 const ArraySubscriptExpr *ASE, 4375 bool AllowOnePastEnd, bool IndexNegated) { 4376 IndexExpr = IndexExpr->IgnoreParenCasts(); 4377 if (IndexExpr->isValueDependent()) 4378 return; 4379 4380 const Type *EffectiveType = getElementType(BaseExpr); 4381 BaseExpr = BaseExpr->IgnoreParenCasts(); 4382 const ConstantArrayType *ArrayTy = 4383 Context.getAsConstantArrayType(BaseExpr->getType()); 4384 if (!ArrayTy) 4385 return; 4386 4387 llvm::APSInt index; 4388 if (!IndexExpr->EvaluateAsInt(index, Context)) 4389 return; 4390 if (IndexNegated) 4391 index = -index; 4392 4393 const NamedDecl *ND = NULL; 4394 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 4395 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 4396 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 4397 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 4398 4399 if (index.isUnsigned() || !index.isNegative()) { 4400 llvm::APInt size = ArrayTy->getSize(); 4401 if (!size.isStrictlyPositive()) 4402 return; 4403 4404 const Type* BaseType = getElementType(BaseExpr); 4405 if (BaseType != EffectiveType) { 4406 // Make sure we're comparing apples to apples when comparing index to size 4407 uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType); 4408 uint64_t array_typesize = Context.getTypeSize(BaseType); 4409 // Handle ptrarith_typesize being zero, such as when casting to void* 4410 if (!ptrarith_typesize) ptrarith_typesize = 1; 4411 if (ptrarith_typesize != array_typesize) { 4412 // There's a cast to a different size type involved 4413 uint64_t ratio = array_typesize / ptrarith_typesize; 4414 // TODO: Be smarter about handling cases where array_typesize is not a 4415 // multiple of ptrarith_typesize 4416 if (ptrarith_typesize * ratio == array_typesize) 4417 size *= llvm::APInt(size.getBitWidth(), ratio); 4418 } 4419 } 4420 4421 if (size.getBitWidth() > index.getBitWidth()) 4422 index = index.sext(size.getBitWidth()); 4423 else if (size.getBitWidth() < index.getBitWidth()) 4424 size = size.sext(index.getBitWidth()); 4425 4426 // For array subscripting the index must be less than size, but for pointer 4427 // arithmetic also allow the index (offset) to be equal to size since 4428 // computing the next address after the end of the array is legal and 4429 // commonly done e.g. in C++ iterators and range-based for loops. 4430 if (AllowOnePastEnd ? index.sle(size) : index.slt(size)) 4431 return; 4432 4433 // Also don't warn for arrays of size 1 which are members of some 4434 // structure. These are often used to approximate flexible arrays in C89 4435 // code. 4436 if (IsTailPaddedMemberArray(*this, size, ND)) 4437 return; 4438 4439 // Suppress the warning if the subscript expression (as identified by the 4440 // ']' location) and the index expression are both from macro expansions 4441 // within a system header. 4442 if (ASE) { 4443 SourceLocation RBracketLoc = SourceMgr.getSpellingLoc( 4444 ASE->getRBracketLoc()); 4445 if (SourceMgr.isInSystemHeader(RBracketLoc)) { 4446 SourceLocation IndexLoc = SourceMgr.getSpellingLoc( 4447 IndexExpr->getLocStart()); 4448 if (SourceMgr.isFromSameFile(RBracketLoc, IndexLoc)) 4449 return; 4450 } 4451 } 4452 4453 unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds; 4454 if (ASE) 4455 DiagID = diag::warn_array_index_exceeds_bounds; 4456 4457 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 4458 PDiag(DiagID) << index.toString(10, true) 4459 << size.toString(10, true) 4460 << (unsigned)size.getLimitedValue(~0U) 4461 << IndexExpr->getSourceRange()); 4462 } else { 4463 unsigned DiagID = diag::warn_array_index_precedes_bounds; 4464 if (!ASE) { 4465 DiagID = diag::warn_ptr_arith_precedes_bounds; 4466 if (index.isNegative()) index = -index; 4467 } 4468 4469 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 4470 PDiag(DiagID) << index.toString(10, true) 4471 << IndexExpr->getSourceRange()); 4472 } 4473 4474 if (!ND) { 4475 // Try harder to find a NamedDecl to point at in the note. 4476 while (const ArraySubscriptExpr *ASE = 4477 dyn_cast<ArraySubscriptExpr>(BaseExpr)) 4478 BaseExpr = ASE->getBase()->IgnoreParenCasts(); 4479 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 4480 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 4481 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 4482 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 4483 } 4484 4485 if (ND) 4486 DiagRuntimeBehavior(ND->getLocStart(), BaseExpr, 4487 PDiag(diag::note_array_index_out_of_bounds) 4488 << ND->getDeclName()); 4489} 4490 4491void Sema::CheckArrayAccess(const Expr *expr) { 4492 int AllowOnePastEnd = 0; 4493 while (expr) { 4494 expr = expr->IgnoreParenImpCasts(); 4495 switch (expr->getStmtClass()) { 4496 case Stmt::ArraySubscriptExprClass: { 4497 const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr); 4498 CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE, 4499 AllowOnePastEnd > 0); 4500 return; 4501 } 4502 case Stmt::UnaryOperatorClass: { 4503 // Only unwrap the * and & unary operators 4504 const UnaryOperator *UO = cast<UnaryOperator>(expr); 4505 expr = UO->getSubExpr(); 4506 switch (UO->getOpcode()) { 4507 case UO_AddrOf: 4508 AllowOnePastEnd++; 4509 break; 4510 case UO_Deref: 4511 AllowOnePastEnd--; 4512 break; 4513 default: 4514 return; 4515 } 4516 break; 4517 } 4518 case Stmt::ConditionalOperatorClass: { 4519 const ConditionalOperator *cond = cast<ConditionalOperator>(expr); 4520 if (const Expr *lhs = cond->getLHS()) 4521 CheckArrayAccess(lhs); 4522 if (const Expr *rhs = cond->getRHS()) 4523 CheckArrayAccess(rhs); 4524 return; 4525 } 4526 default: 4527 return; 4528 } 4529 } 4530} 4531 4532//===--- CHECK: Objective-C retain cycles ----------------------------------// 4533 4534namespace { 4535 struct RetainCycleOwner { 4536 RetainCycleOwner() : Variable(0), Indirect(false) {} 4537 VarDecl *Variable; 4538 SourceRange Range; 4539 SourceLocation Loc; 4540 bool Indirect; 4541 4542 void setLocsFrom(Expr *e) { 4543 Loc = e->getExprLoc(); 4544 Range = e->getSourceRange(); 4545 } 4546 }; 4547} 4548 4549/// Consider whether capturing the given variable can possibly lead to 4550/// a retain cycle. 4551static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) { 4552 // In ARC, it's captured strongly iff the variable has __strong 4553 // lifetime. In MRR, it's captured strongly if the variable is 4554 // __block and has an appropriate type. 4555 if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 4556 return false; 4557 4558 owner.Variable = var; 4559 owner.setLocsFrom(ref); 4560 return true; 4561} 4562 4563static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) { 4564 while (true) { 4565 e = e->IgnoreParens(); 4566 if (CastExpr *cast = dyn_cast<CastExpr>(e)) { 4567 switch (cast->getCastKind()) { 4568 case CK_BitCast: 4569 case CK_LValueBitCast: 4570 case CK_LValueToRValue: 4571 case CK_ARCReclaimReturnedObject: 4572 e = cast->getSubExpr(); 4573 continue; 4574 4575 default: 4576 return false; 4577 } 4578 } 4579 4580 if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) { 4581 ObjCIvarDecl *ivar = ref->getDecl(); 4582 if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 4583 return false; 4584 4585 // Try to find a retain cycle in the base. 4586 if (!findRetainCycleOwner(S, ref->getBase(), owner)) 4587 return false; 4588 4589 if (ref->isFreeIvar()) owner.setLocsFrom(ref); 4590 owner.Indirect = true; 4591 return true; 4592 } 4593 4594 if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) { 4595 VarDecl *var = dyn_cast<VarDecl>(ref->getDecl()); 4596 if (!var) return false; 4597 return considerVariable(var, ref, owner); 4598 } 4599 4600 if (BlockDeclRefExpr *ref = dyn_cast<BlockDeclRefExpr>(e)) { 4601 owner.Variable = ref->getDecl(); 4602 owner.setLocsFrom(ref); 4603 return true; 4604 } 4605 4606 if (MemberExpr *member = dyn_cast<MemberExpr>(e)) { 4607 if (member->isArrow()) return false; 4608 4609 // Don't count this as an indirect ownership. 4610 e = member->getBase(); 4611 continue; 4612 } 4613 4614 if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) { 4615 // Only pay attention to pseudo-objects on property references. 4616 ObjCPropertyRefExpr *pre 4617 = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm() 4618 ->IgnoreParens()); 4619 if (!pre) return false; 4620 if (pre->isImplicitProperty()) return false; 4621 ObjCPropertyDecl *property = pre->getExplicitProperty(); 4622 if (!property->isRetaining() && 4623 !(property->getPropertyIvarDecl() && 4624 property->getPropertyIvarDecl()->getType() 4625 .getObjCLifetime() == Qualifiers::OCL_Strong)) 4626 return false; 4627 4628 owner.Indirect = true; 4629 if (pre->isSuperReceiver()) { 4630 owner.Variable = S.getCurMethodDecl()->getSelfDecl(); 4631 if (!owner.Variable) 4632 return false; 4633 owner.Loc = pre->getLocation(); 4634 owner.Range = pre->getSourceRange(); 4635 return true; 4636 } 4637 e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase()) 4638 ->getSourceExpr()); 4639 continue; 4640 } 4641 4642 // Array ivars? 4643 4644 return false; 4645 } 4646} 4647 4648namespace { 4649 struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> { 4650 FindCaptureVisitor(ASTContext &Context, VarDecl *variable) 4651 : EvaluatedExprVisitor<FindCaptureVisitor>(Context), 4652 Variable(variable), Capturer(0) {} 4653 4654 VarDecl *Variable; 4655 Expr *Capturer; 4656 4657 void VisitDeclRefExpr(DeclRefExpr *ref) { 4658 if (ref->getDecl() == Variable && !Capturer) 4659 Capturer = ref; 4660 } 4661 4662 void VisitBlockDeclRefExpr(BlockDeclRefExpr *ref) { 4663 if (ref->getDecl() == Variable && !Capturer) 4664 Capturer = ref; 4665 } 4666 4667 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) { 4668 if (Capturer) return; 4669 Visit(ref->getBase()); 4670 if (Capturer && ref->isFreeIvar()) 4671 Capturer = ref; 4672 } 4673 4674 void VisitBlockExpr(BlockExpr *block) { 4675 // Look inside nested blocks 4676 if (block->getBlockDecl()->capturesVariable(Variable)) 4677 Visit(block->getBlockDecl()->getBody()); 4678 } 4679 }; 4680} 4681 4682/// Check whether the given argument is a block which captures a 4683/// variable. 4684static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) { 4685 assert(owner.Variable && owner.Loc.isValid()); 4686 4687 e = e->IgnoreParenCasts(); 4688 BlockExpr *block = dyn_cast<BlockExpr>(e); 4689 if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable)) 4690 return 0; 4691 4692 FindCaptureVisitor visitor(S.Context, owner.Variable); 4693 visitor.Visit(block->getBlockDecl()->getBody()); 4694 return visitor.Capturer; 4695} 4696 4697static void diagnoseRetainCycle(Sema &S, Expr *capturer, 4698 RetainCycleOwner &owner) { 4699 assert(capturer); 4700 assert(owner.Variable && owner.Loc.isValid()); 4701 4702 S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle) 4703 << owner.Variable << capturer->getSourceRange(); 4704 S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner) 4705 << owner.Indirect << owner.Range; 4706} 4707 4708/// Check for a keyword selector that starts with the word 'add' or 4709/// 'set'. 4710static bool isSetterLikeSelector(Selector sel) { 4711 if (sel.isUnarySelector()) return false; 4712 4713 StringRef str = sel.getNameForSlot(0); 4714 while (!str.empty() && str.front() == '_') str = str.substr(1); 4715 if (str.startswith("set")) 4716 str = str.substr(3); 4717 else if (str.startswith("add")) { 4718 // Specially whitelist 'addOperationWithBlock:'. 4719 if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock")) 4720 return false; 4721 str = str.substr(3); 4722 } 4723 else 4724 return false; 4725 4726 if (str.empty()) return true; 4727 return !islower(str.front()); 4728} 4729 4730/// Check a message send to see if it's likely to cause a retain cycle. 4731void Sema::checkRetainCycles(ObjCMessageExpr *msg) { 4732 // Only check instance methods whose selector looks like a setter. 4733 if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector())) 4734 return; 4735 4736 // Try to find a variable that the receiver is strongly owned by. 4737 RetainCycleOwner owner; 4738 if (msg->getReceiverKind() == ObjCMessageExpr::Instance) { 4739 if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner)) 4740 return; 4741 } else { 4742 assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance); 4743 owner.Variable = getCurMethodDecl()->getSelfDecl(); 4744 owner.Loc = msg->getSuperLoc(); 4745 owner.Range = msg->getSuperLoc(); 4746 } 4747 4748 // Check whether the receiver is captured by any of the arguments. 4749 for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i) 4750 if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner)) 4751 return diagnoseRetainCycle(*this, capturer, owner); 4752} 4753 4754/// Check a property assign to see if it's likely to cause a retain cycle. 4755void Sema::checkRetainCycles(Expr *receiver, Expr *argument) { 4756 RetainCycleOwner owner; 4757 if (!findRetainCycleOwner(*this, receiver, owner)) 4758 return; 4759 4760 if (Expr *capturer = findCapturingExpr(*this, argument, owner)) 4761 diagnoseRetainCycle(*this, capturer, owner); 4762} 4763 4764bool Sema::checkUnsafeAssigns(SourceLocation Loc, 4765 QualType LHS, Expr *RHS) { 4766 Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime(); 4767 if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone) 4768 return false; 4769 // strip off any implicit cast added to get to the one arc-specific 4770 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 4771 if (cast->getCastKind() == CK_ARCConsumeObject) { 4772 Diag(Loc, diag::warn_arc_retained_assign) 4773 << (LT == Qualifiers::OCL_ExplicitNone) 4774 << RHS->getSourceRange(); 4775 return true; 4776 } 4777 RHS = cast->getSubExpr(); 4778 } 4779 return false; 4780} 4781 4782void Sema::checkUnsafeExprAssigns(SourceLocation Loc, 4783 Expr *LHS, Expr *RHS) { 4784 QualType LHSType; 4785 // PropertyRef on LHS type need be directly obtained from 4786 // its declaration as it has a PsuedoType. 4787 ObjCPropertyRefExpr *PRE 4788 = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens()); 4789 if (PRE && !PRE->isImplicitProperty()) { 4790 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 4791 if (PD) 4792 LHSType = PD->getType(); 4793 } 4794 4795 if (LHSType.isNull()) 4796 LHSType = LHS->getType(); 4797 if (checkUnsafeAssigns(Loc, LHSType, RHS)) 4798 return; 4799 Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime(); 4800 // FIXME. Check for other life times. 4801 if (LT != Qualifiers::OCL_None) 4802 return; 4803 4804 if (PRE) { 4805 if (PRE->isImplicitProperty()) 4806 return; 4807 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 4808 if (!PD) 4809 return; 4810 4811 unsigned Attributes = PD->getPropertyAttributes(); 4812 if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) { 4813 // when 'assign' attribute was not explicitly specified 4814 // by user, ignore it and rely on property type itself 4815 // for lifetime info. 4816 unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten(); 4817 if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) && 4818 LHSType->isObjCRetainableType()) 4819 return; 4820 4821 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 4822 if (cast->getCastKind() == CK_ARCConsumeObject) { 4823 Diag(Loc, diag::warn_arc_retained_property_assign) 4824 << RHS->getSourceRange(); 4825 return; 4826 } 4827 RHS = cast->getSubExpr(); 4828 } 4829 } 4830 } 4831} 4832 4833//===--- CHECK: Empty statement body (-Wempty-body) ---------------------===// 4834 4835namespace { 4836bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr, 4837 SourceLocation StmtLoc, 4838 const NullStmt *Body) { 4839 // Do not warn if the body is a macro that expands to nothing, e.g: 4840 // 4841 // #define CALL(x) 4842 // if (condition) 4843 // CALL(0); 4844 // 4845 if (Body->hasLeadingEmptyMacro()) 4846 return false; 4847 4848 // Get line numbers of statement and body. 4849 bool StmtLineInvalid; 4850 unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc, 4851 &StmtLineInvalid); 4852 if (StmtLineInvalid) 4853 return false; 4854 4855 bool BodyLineInvalid; 4856 unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(), 4857 &BodyLineInvalid); 4858 if (BodyLineInvalid) 4859 return false; 4860 4861 // Warn if null statement and body are on the same line. 4862 if (StmtLine != BodyLine) 4863 return false; 4864 4865 return true; 4866} 4867} // Unnamed namespace 4868 4869void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc, 4870 const Stmt *Body, 4871 unsigned DiagID) { 4872 // Since this is a syntactic check, don't emit diagnostic for template 4873 // instantiations, this just adds noise. 4874 if (CurrentInstantiationScope) 4875 return; 4876 4877 // The body should be a null statement. 4878 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 4879 if (!NBody) 4880 return; 4881 4882 // Do the usual checks. 4883 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 4884 return; 4885 4886 Diag(NBody->getSemiLoc(), DiagID); 4887 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 4888} 4889 4890void Sema::DiagnoseEmptyLoopBody(const Stmt *S, 4891 const Stmt *PossibleBody) { 4892 assert(!CurrentInstantiationScope); // Ensured by caller 4893 4894 SourceLocation StmtLoc; 4895 const Stmt *Body; 4896 unsigned DiagID; 4897 if (const ForStmt *FS = dyn_cast<ForStmt>(S)) { 4898 StmtLoc = FS->getRParenLoc(); 4899 Body = FS->getBody(); 4900 DiagID = diag::warn_empty_for_body; 4901 } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) { 4902 StmtLoc = WS->getCond()->getSourceRange().getEnd(); 4903 Body = WS->getBody(); 4904 DiagID = diag::warn_empty_while_body; 4905 } else 4906 return; // Neither `for' nor `while'. 4907 4908 // The body should be a null statement. 4909 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 4910 if (!NBody) 4911 return; 4912 4913 // Skip expensive checks if diagnostic is disabled. 4914 if (Diags.getDiagnosticLevel(DiagID, NBody->getSemiLoc()) == 4915 DiagnosticsEngine::Ignored) 4916 return; 4917 4918 // Do the usual checks. 4919 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 4920 return; 4921 4922 // `for(...);' and `while(...);' are popular idioms, so in order to keep 4923 // noise level low, emit diagnostics only if for/while is followed by a 4924 // CompoundStmt, e.g.: 4925 // for (int i = 0; i < n; i++); 4926 // { 4927 // a(i); 4928 // } 4929 // or if for/while is followed by a statement with more indentation 4930 // than for/while itself: 4931 // for (int i = 0; i < n; i++); 4932 // a(i); 4933 bool ProbableTypo = isa<CompoundStmt>(PossibleBody); 4934 if (!ProbableTypo) { 4935 bool BodyColInvalid; 4936 unsigned BodyCol = SourceMgr.getPresumedColumnNumber( 4937 PossibleBody->getLocStart(), 4938 &BodyColInvalid); 4939 if (BodyColInvalid) 4940 return; 4941 4942 bool StmtColInvalid; 4943 unsigned StmtCol = SourceMgr.getPresumedColumnNumber( 4944 S->getLocStart(), 4945 &StmtColInvalid); 4946 if (StmtColInvalid) 4947 return; 4948 4949 if (BodyCol > StmtCol) 4950 ProbableTypo = true; 4951 } 4952 4953 if (ProbableTypo) { 4954 Diag(NBody->getSemiLoc(), DiagID); 4955 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 4956 } 4957} 4958 4959