SemaChecking.cpp revision bbb6bb4952b77e57b842b4d3096848123ae690e7
1//===--- SemaChecking.cpp - Extra Semantic Checking -----------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements extra semantic analysis beyond what is enforced 11// by the C type system. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/Sema/Initialization.h" 16#include "clang/Sema/Sema.h" 17#include "clang/Sema/SemaInternal.h" 18#include "clang/Sema/Initialization.h" 19#include "clang/Sema/Lookup.h" 20#include "clang/Sema/ScopeInfo.h" 21#include "clang/Analysis/Analyses/FormatString.h" 22#include "clang/AST/ASTContext.h" 23#include "clang/AST/CharUnits.h" 24#include "clang/AST/DeclCXX.h" 25#include "clang/AST/DeclObjC.h" 26#include "clang/AST/Expr.h" 27#include "clang/AST/ExprCXX.h" 28#include "clang/AST/ExprObjC.h" 29#include "clang/AST/EvaluatedExprVisitor.h" 30#include "clang/AST/DeclObjC.h" 31#include "clang/AST/StmtCXX.h" 32#include "clang/AST/StmtObjC.h" 33#include "clang/Lex/Preprocessor.h" 34#include "llvm/ADT/BitVector.h" 35#include "llvm/ADT/SmallString.h" 36#include "llvm/ADT/STLExtras.h" 37#include "llvm/Support/raw_ostream.h" 38#include "clang/Basic/TargetBuiltins.h" 39#include "clang/Basic/TargetInfo.h" 40#include "clang/Basic/ConvertUTF.h" 41#include <limits> 42using namespace clang; 43using namespace sema; 44 45SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL, 46 unsigned ByteNo) const { 47 return SL->getLocationOfByte(ByteNo, PP.getSourceManager(), 48 PP.getLangOpts(), PP.getTargetInfo()); 49} 50 51/// Checks that a call expression's argument count is the desired number. 52/// This is useful when doing custom type-checking. Returns true on error. 53static bool checkArgCount(Sema &S, CallExpr *call, unsigned desiredArgCount) { 54 unsigned argCount = call->getNumArgs(); 55 if (argCount == desiredArgCount) return false; 56 57 if (argCount < desiredArgCount) 58 return S.Diag(call->getLocEnd(), diag::err_typecheck_call_too_few_args) 59 << 0 /*function call*/ << desiredArgCount << argCount 60 << call->getSourceRange(); 61 62 // Highlight all the excess arguments. 63 SourceRange range(call->getArg(desiredArgCount)->getLocStart(), 64 call->getArg(argCount - 1)->getLocEnd()); 65 66 return S.Diag(range.getBegin(), diag::err_typecheck_call_too_many_args) 67 << 0 /*function call*/ << desiredArgCount << argCount 68 << call->getArg(1)->getSourceRange(); 69} 70 71/// Check that the first argument to __builtin_annotation is an integer 72/// and the second argument is a non-wide string literal. 73static bool SemaBuiltinAnnotation(Sema &S, CallExpr *TheCall) { 74 if (checkArgCount(S, TheCall, 2)) 75 return true; 76 77 // First argument should be an integer. 78 Expr *ValArg = TheCall->getArg(0); 79 QualType Ty = ValArg->getType(); 80 if (!Ty->isIntegerType()) { 81 S.Diag(ValArg->getLocStart(), diag::err_builtin_annotation_first_arg) 82 << ValArg->getSourceRange(); 83 return true; 84 } 85 86 // Second argument should be a constant string. 87 Expr *StrArg = TheCall->getArg(1)->IgnoreParenCasts(); 88 StringLiteral *Literal = dyn_cast<StringLiteral>(StrArg); 89 if (!Literal || !Literal->isAscii()) { 90 S.Diag(StrArg->getLocStart(), diag::err_builtin_annotation_second_arg) 91 << StrArg->getSourceRange(); 92 return true; 93 } 94 95 TheCall->setType(Ty); 96 return false; 97} 98 99ExprResult 100Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 101 ExprResult TheCallResult(Owned(TheCall)); 102 103 // Find out if any arguments are required to be integer constant expressions. 104 unsigned ICEArguments = 0; 105 ASTContext::GetBuiltinTypeError Error; 106 Context.GetBuiltinType(BuiltinID, Error, &ICEArguments); 107 if (Error != ASTContext::GE_None) 108 ICEArguments = 0; // Don't diagnose previously diagnosed errors. 109 110 // If any arguments are required to be ICE's, check and diagnose. 111 for (unsigned ArgNo = 0; ICEArguments != 0; ++ArgNo) { 112 // Skip arguments not required to be ICE's. 113 if ((ICEArguments & (1 << ArgNo)) == 0) continue; 114 115 llvm::APSInt Result; 116 if (SemaBuiltinConstantArg(TheCall, ArgNo, Result)) 117 return true; 118 ICEArguments &= ~(1 << ArgNo); 119 } 120 121 switch (BuiltinID) { 122 case Builtin::BI__builtin___CFStringMakeConstantString: 123 assert(TheCall->getNumArgs() == 1 && 124 "Wrong # arguments to builtin CFStringMakeConstantString"); 125 if (CheckObjCString(TheCall->getArg(0))) 126 return ExprError(); 127 break; 128 case Builtin::BI__builtin_stdarg_start: 129 case Builtin::BI__builtin_va_start: 130 if (SemaBuiltinVAStart(TheCall)) 131 return ExprError(); 132 break; 133 case Builtin::BI__builtin_isgreater: 134 case Builtin::BI__builtin_isgreaterequal: 135 case Builtin::BI__builtin_isless: 136 case Builtin::BI__builtin_islessequal: 137 case Builtin::BI__builtin_islessgreater: 138 case Builtin::BI__builtin_isunordered: 139 if (SemaBuiltinUnorderedCompare(TheCall)) 140 return ExprError(); 141 break; 142 case Builtin::BI__builtin_fpclassify: 143 if (SemaBuiltinFPClassification(TheCall, 6)) 144 return ExprError(); 145 break; 146 case Builtin::BI__builtin_isfinite: 147 case Builtin::BI__builtin_isinf: 148 case Builtin::BI__builtin_isinf_sign: 149 case Builtin::BI__builtin_isnan: 150 case Builtin::BI__builtin_isnormal: 151 if (SemaBuiltinFPClassification(TheCall, 1)) 152 return ExprError(); 153 break; 154 case Builtin::BI__builtin_shufflevector: 155 return SemaBuiltinShuffleVector(TheCall); 156 // TheCall will be freed by the smart pointer here, but that's fine, since 157 // SemaBuiltinShuffleVector guts it, but then doesn't release it. 158 case Builtin::BI__builtin_prefetch: 159 if (SemaBuiltinPrefetch(TheCall)) 160 return ExprError(); 161 break; 162 case Builtin::BI__builtin_object_size: 163 if (SemaBuiltinObjectSize(TheCall)) 164 return ExprError(); 165 break; 166 case Builtin::BI__builtin_longjmp: 167 if (SemaBuiltinLongjmp(TheCall)) 168 return ExprError(); 169 break; 170 171 case Builtin::BI__builtin_classify_type: 172 if (checkArgCount(*this, TheCall, 1)) return true; 173 TheCall->setType(Context.IntTy); 174 break; 175 case Builtin::BI__builtin_constant_p: 176 if (checkArgCount(*this, TheCall, 1)) return true; 177 TheCall->setType(Context.IntTy); 178 break; 179 case Builtin::BI__sync_fetch_and_add: 180 case Builtin::BI__sync_fetch_and_add_1: 181 case Builtin::BI__sync_fetch_and_add_2: 182 case Builtin::BI__sync_fetch_and_add_4: 183 case Builtin::BI__sync_fetch_and_add_8: 184 case Builtin::BI__sync_fetch_and_add_16: 185 case Builtin::BI__sync_fetch_and_sub: 186 case Builtin::BI__sync_fetch_and_sub_1: 187 case Builtin::BI__sync_fetch_and_sub_2: 188 case Builtin::BI__sync_fetch_and_sub_4: 189 case Builtin::BI__sync_fetch_and_sub_8: 190 case Builtin::BI__sync_fetch_and_sub_16: 191 case Builtin::BI__sync_fetch_and_or: 192 case Builtin::BI__sync_fetch_and_or_1: 193 case Builtin::BI__sync_fetch_and_or_2: 194 case Builtin::BI__sync_fetch_and_or_4: 195 case Builtin::BI__sync_fetch_and_or_8: 196 case Builtin::BI__sync_fetch_and_or_16: 197 case Builtin::BI__sync_fetch_and_and: 198 case Builtin::BI__sync_fetch_and_and_1: 199 case Builtin::BI__sync_fetch_and_and_2: 200 case Builtin::BI__sync_fetch_and_and_4: 201 case Builtin::BI__sync_fetch_and_and_8: 202 case Builtin::BI__sync_fetch_and_and_16: 203 case Builtin::BI__sync_fetch_and_xor: 204 case Builtin::BI__sync_fetch_and_xor_1: 205 case Builtin::BI__sync_fetch_and_xor_2: 206 case Builtin::BI__sync_fetch_and_xor_4: 207 case Builtin::BI__sync_fetch_and_xor_8: 208 case Builtin::BI__sync_fetch_and_xor_16: 209 case Builtin::BI__sync_add_and_fetch: 210 case Builtin::BI__sync_add_and_fetch_1: 211 case Builtin::BI__sync_add_and_fetch_2: 212 case Builtin::BI__sync_add_and_fetch_4: 213 case Builtin::BI__sync_add_and_fetch_8: 214 case Builtin::BI__sync_add_and_fetch_16: 215 case Builtin::BI__sync_sub_and_fetch: 216 case Builtin::BI__sync_sub_and_fetch_1: 217 case Builtin::BI__sync_sub_and_fetch_2: 218 case Builtin::BI__sync_sub_and_fetch_4: 219 case Builtin::BI__sync_sub_and_fetch_8: 220 case Builtin::BI__sync_sub_and_fetch_16: 221 case Builtin::BI__sync_and_and_fetch: 222 case Builtin::BI__sync_and_and_fetch_1: 223 case Builtin::BI__sync_and_and_fetch_2: 224 case Builtin::BI__sync_and_and_fetch_4: 225 case Builtin::BI__sync_and_and_fetch_8: 226 case Builtin::BI__sync_and_and_fetch_16: 227 case Builtin::BI__sync_or_and_fetch: 228 case Builtin::BI__sync_or_and_fetch_1: 229 case Builtin::BI__sync_or_and_fetch_2: 230 case Builtin::BI__sync_or_and_fetch_4: 231 case Builtin::BI__sync_or_and_fetch_8: 232 case Builtin::BI__sync_or_and_fetch_16: 233 case Builtin::BI__sync_xor_and_fetch: 234 case Builtin::BI__sync_xor_and_fetch_1: 235 case Builtin::BI__sync_xor_and_fetch_2: 236 case Builtin::BI__sync_xor_and_fetch_4: 237 case Builtin::BI__sync_xor_and_fetch_8: 238 case Builtin::BI__sync_xor_and_fetch_16: 239 case Builtin::BI__sync_val_compare_and_swap: 240 case Builtin::BI__sync_val_compare_and_swap_1: 241 case Builtin::BI__sync_val_compare_and_swap_2: 242 case Builtin::BI__sync_val_compare_and_swap_4: 243 case Builtin::BI__sync_val_compare_and_swap_8: 244 case Builtin::BI__sync_val_compare_and_swap_16: 245 case Builtin::BI__sync_bool_compare_and_swap: 246 case Builtin::BI__sync_bool_compare_and_swap_1: 247 case Builtin::BI__sync_bool_compare_and_swap_2: 248 case Builtin::BI__sync_bool_compare_and_swap_4: 249 case Builtin::BI__sync_bool_compare_and_swap_8: 250 case Builtin::BI__sync_bool_compare_and_swap_16: 251 case Builtin::BI__sync_lock_test_and_set: 252 case Builtin::BI__sync_lock_test_and_set_1: 253 case Builtin::BI__sync_lock_test_and_set_2: 254 case Builtin::BI__sync_lock_test_and_set_4: 255 case Builtin::BI__sync_lock_test_and_set_8: 256 case Builtin::BI__sync_lock_test_and_set_16: 257 case Builtin::BI__sync_lock_release: 258 case Builtin::BI__sync_lock_release_1: 259 case Builtin::BI__sync_lock_release_2: 260 case Builtin::BI__sync_lock_release_4: 261 case Builtin::BI__sync_lock_release_8: 262 case Builtin::BI__sync_lock_release_16: 263 case Builtin::BI__sync_swap: 264 case Builtin::BI__sync_swap_1: 265 case Builtin::BI__sync_swap_2: 266 case Builtin::BI__sync_swap_4: 267 case Builtin::BI__sync_swap_8: 268 case Builtin::BI__sync_swap_16: 269 return SemaBuiltinAtomicOverloaded(TheCallResult); 270#define BUILTIN(ID, TYPE, ATTRS) 271#define ATOMIC_BUILTIN(ID, TYPE, ATTRS) \ 272 case Builtin::BI##ID: \ 273 return SemaAtomicOpsOverloaded(TheCallResult, AtomicExpr::AO##ID); 274#include "clang/Basic/Builtins.def" 275 case Builtin::BI__builtin_annotation: 276 if (SemaBuiltinAnnotation(*this, TheCall)) 277 return ExprError(); 278 break; 279 } 280 281 // Since the target specific builtins for each arch overlap, only check those 282 // of the arch we are compiling for. 283 if (BuiltinID >= Builtin::FirstTSBuiltin) { 284 switch (Context.getTargetInfo().getTriple().getArch()) { 285 case llvm::Triple::arm: 286 case llvm::Triple::thumb: 287 if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall)) 288 return ExprError(); 289 break; 290 case llvm::Triple::mips: 291 case llvm::Triple::mipsel: 292 case llvm::Triple::mips64: 293 case llvm::Triple::mips64el: 294 if (CheckMipsBuiltinFunctionCall(BuiltinID, TheCall)) 295 return ExprError(); 296 break; 297 default: 298 break; 299 } 300 } 301 302 return TheCallResult; 303} 304 305// Get the valid immediate range for the specified NEON type code. 306static unsigned RFT(unsigned t, bool shift = false) { 307 NeonTypeFlags Type(t); 308 int IsQuad = Type.isQuad(); 309 switch (Type.getEltType()) { 310 case NeonTypeFlags::Int8: 311 case NeonTypeFlags::Poly8: 312 return shift ? 7 : (8 << IsQuad) - 1; 313 case NeonTypeFlags::Int16: 314 case NeonTypeFlags::Poly16: 315 return shift ? 15 : (4 << IsQuad) - 1; 316 case NeonTypeFlags::Int32: 317 return shift ? 31 : (2 << IsQuad) - 1; 318 case NeonTypeFlags::Int64: 319 return shift ? 63 : (1 << IsQuad) - 1; 320 case NeonTypeFlags::Float16: 321 assert(!shift && "cannot shift float types!"); 322 return (4 << IsQuad) - 1; 323 case NeonTypeFlags::Float32: 324 assert(!shift && "cannot shift float types!"); 325 return (2 << IsQuad) - 1; 326 } 327 llvm_unreachable("Invalid NeonTypeFlag!"); 328} 329 330/// getNeonEltType - Return the QualType corresponding to the elements of 331/// the vector type specified by the NeonTypeFlags. This is used to check 332/// the pointer arguments for Neon load/store intrinsics. 333static QualType getNeonEltType(NeonTypeFlags Flags, ASTContext &Context) { 334 switch (Flags.getEltType()) { 335 case NeonTypeFlags::Int8: 336 return Flags.isUnsigned() ? Context.UnsignedCharTy : Context.SignedCharTy; 337 case NeonTypeFlags::Int16: 338 return Flags.isUnsigned() ? Context.UnsignedShortTy : Context.ShortTy; 339 case NeonTypeFlags::Int32: 340 return Flags.isUnsigned() ? Context.UnsignedIntTy : Context.IntTy; 341 case NeonTypeFlags::Int64: 342 return Flags.isUnsigned() ? Context.UnsignedLongLongTy : Context.LongLongTy; 343 case NeonTypeFlags::Poly8: 344 return Context.SignedCharTy; 345 case NeonTypeFlags::Poly16: 346 return Context.ShortTy; 347 case NeonTypeFlags::Float16: 348 return Context.UnsignedShortTy; 349 case NeonTypeFlags::Float32: 350 return Context.FloatTy; 351 } 352 llvm_unreachable("Invalid NeonTypeFlag!"); 353} 354 355bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 356 llvm::APSInt Result; 357 358 uint64_t mask = 0; 359 unsigned TV = 0; 360 int PtrArgNum = -1; 361 bool HasConstPtr = false; 362 switch (BuiltinID) { 363#define GET_NEON_OVERLOAD_CHECK 364#include "clang/Basic/arm_neon.inc" 365#undef GET_NEON_OVERLOAD_CHECK 366 } 367 368 // For NEON intrinsics which are overloaded on vector element type, validate 369 // the immediate which specifies which variant to emit. 370 unsigned ImmArg = TheCall->getNumArgs()-1; 371 if (mask) { 372 if (SemaBuiltinConstantArg(TheCall, ImmArg, Result)) 373 return true; 374 375 TV = Result.getLimitedValue(64); 376 if ((TV > 63) || (mask & (1ULL << TV)) == 0) 377 return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code) 378 << TheCall->getArg(ImmArg)->getSourceRange(); 379 } 380 381 if (PtrArgNum >= 0) { 382 // Check that pointer arguments have the specified type. 383 Expr *Arg = TheCall->getArg(PtrArgNum); 384 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) 385 Arg = ICE->getSubExpr(); 386 ExprResult RHS = DefaultFunctionArrayLvalueConversion(Arg); 387 QualType RHSTy = RHS.get()->getType(); 388 QualType EltTy = getNeonEltType(NeonTypeFlags(TV), Context); 389 if (HasConstPtr) 390 EltTy = EltTy.withConst(); 391 QualType LHSTy = Context.getPointerType(EltTy); 392 AssignConvertType ConvTy; 393 ConvTy = CheckSingleAssignmentConstraints(LHSTy, RHS); 394 if (RHS.isInvalid()) 395 return true; 396 if (DiagnoseAssignmentResult(ConvTy, Arg->getLocStart(), LHSTy, RHSTy, 397 RHS.get(), AA_Assigning)) 398 return true; 399 } 400 401 // For NEON intrinsics which take an immediate value as part of the 402 // instruction, range check them here. 403 unsigned i = 0, l = 0, u = 0; 404 switch (BuiltinID) { 405 default: return false; 406 case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break; 407 case ARM::BI__builtin_arm_usat: i = 1; u = 31; break; 408 case ARM::BI__builtin_arm_vcvtr_f: 409 case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break; 410#define GET_NEON_IMMEDIATE_CHECK 411#include "clang/Basic/arm_neon.inc" 412#undef GET_NEON_IMMEDIATE_CHECK 413 }; 414 415 // We can't check the value of a dependent argument. 416 if (TheCall->getArg(i)->isTypeDependent() || 417 TheCall->getArg(i)->isValueDependent()) 418 return false; 419 420 // Check that the immediate argument is actually a constant. 421 if (SemaBuiltinConstantArg(TheCall, i, Result)) 422 return true; 423 424 // Range check against the upper/lower values for this isntruction. 425 unsigned Val = Result.getZExtValue(); 426 if (Val < l || Val > (u + l)) 427 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 428 << l << u+l << TheCall->getArg(i)->getSourceRange(); 429 430 // FIXME: VFP Intrinsics should error if VFP not present. 431 return false; 432} 433 434bool Sema::CheckMipsBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 435 unsigned i = 0, l = 0, u = 0; 436 switch (BuiltinID) { 437 default: return false; 438 case Mips::BI__builtin_mips_wrdsp: i = 1; l = 0; u = 63; break; 439 case Mips::BI__builtin_mips_rddsp: i = 0; l = 0; u = 63; break; 440 case Mips::BI__builtin_mips_append: i = 2; l = 0; u = 31; break; 441 case Mips::BI__builtin_mips_balign: i = 2; l = 0; u = 3; break; 442 case Mips::BI__builtin_mips_precr_sra_ph_w: i = 2; l = 0; u = 31; break; 443 case Mips::BI__builtin_mips_precr_sra_r_ph_w: i = 2; l = 0; u = 31; break; 444 case Mips::BI__builtin_mips_prepend: i = 2; l = 0; u = 31; break; 445 }; 446 447 // We can't check the value of a dependent argument. 448 if (TheCall->getArg(i)->isTypeDependent() || 449 TheCall->getArg(i)->isValueDependent()) 450 return false; 451 452 // Check that the immediate argument is actually a constant. 453 llvm::APSInt Result; 454 if (SemaBuiltinConstantArg(TheCall, i, Result)) 455 return true; 456 457 // Range check against the upper/lower values for this instruction. 458 unsigned Val = Result.getZExtValue(); 459 if (Val < l || Val > u) 460 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 461 << l << u << TheCall->getArg(i)->getSourceRange(); 462 463 return false; 464} 465 466/// Given a FunctionDecl's FormatAttr, attempts to populate the FomatStringInfo 467/// parameter with the FormatAttr's correct format_idx and firstDataArg. 468/// Returns true when the format fits the function and the FormatStringInfo has 469/// been populated. 470bool Sema::getFormatStringInfo(const FormatAttr *Format, bool IsCXXMember, 471 FormatStringInfo *FSI) { 472 FSI->HasVAListArg = Format->getFirstArg() == 0; 473 FSI->FormatIdx = Format->getFormatIdx() - 1; 474 FSI->FirstDataArg = FSI->HasVAListArg ? 0 : Format->getFirstArg() - 1; 475 476 // The way the format attribute works in GCC, the implicit this argument 477 // of member functions is counted. However, it doesn't appear in our own 478 // lists, so decrement format_idx in that case. 479 if (IsCXXMember) { 480 if(FSI->FormatIdx == 0) 481 return false; 482 --FSI->FormatIdx; 483 if (FSI->FirstDataArg != 0) 484 --FSI->FirstDataArg; 485 } 486 return true; 487} 488 489/// Handles the checks for format strings, non-POD arguments to vararg 490/// functions, and NULL arguments passed to non-NULL parameters. 491void Sema::checkCall(NamedDecl *FDecl, Expr **Args, 492 unsigned NumArgs, 493 unsigned NumProtoArgs, 494 bool IsMemberFunction, 495 SourceLocation Loc, 496 SourceRange Range, 497 VariadicCallType CallType) { 498 // FIXME: This mechanism should be abstracted to be less fragile and 499 // more efficient. For example, just map function ids to custom 500 // handlers. 501 502 // Printf and scanf checking. 503 bool HandledFormatString = false; 504 for (specific_attr_iterator<FormatAttr> 505 I = FDecl->specific_attr_begin<FormatAttr>(), 506 E = FDecl->specific_attr_end<FormatAttr>(); I != E ; ++I) 507 if (CheckFormatArguments(*I, Args, NumArgs, IsMemberFunction, CallType, 508 Loc, Range)) 509 HandledFormatString = true; 510 511 // Refuse POD arguments that weren't caught by the format string 512 // checks above. 513 if (!HandledFormatString && CallType != VariadicDoesNotApply) 514 for (unsigned ArgIdx = NumProtoArgs; ArgIdx < NumArgs; ++ArgIdx) 515 variadicArgumentPODCheck(Args[ArgIdx], CallType); 516 517 for (specific_attr_iterator<NonNullAttr> 518 I = FDecl->specific_attr_begin<NonNullAttr>(), 519 E = FDecl->specific_attr_end<NonNullAttr>(); I != E; ++I) 520 CheckNonNullArguments(*I, Args, Loc); 521 522 // Type safety checking. 523 for (specific_attr_iterator<ArgumentWithTypeTagAttr> 524 i = FDecl->specific_attr_begin<ArgumentWithTypeTagAttr>(), 525 e = FDecl->specific_attr_end<ArgumentWithTypeTagAttr>(); i != e; ++i) { 526 CheckArgumentWithTypeTag(*i, Args); 527 } 528} 529 530/// CheckConstructorCall - Check a constructor call for correctness and safety 531/// properties not enforced by the C type system. 532void Sema::CheckConstructorCall(FunctionDecl *FDecl, Expr **Args, 533 unsigned NumArgs, 534 const FunctionProtoType *Proto, 535 SourceLocation Loc) { 536 VariadicCallType CallType = 537 Proto->isVariadic() ? VariadicConstructor : VariadicDoesNotApply; 538 checkCall(FDecl, Args, NumArgs, Proto->getNumArgs(), 539 /*IsMemberFunction=*/true, Loc, SourceRange(), CallType); 540} 541 542/// CheckFunctionCall - Check a direct function call for various correctness 543/// and safety properties not strictly enforced by the C type system. 544bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall, 545 const FunctionProtoType *Proto) { 546 bool IsMemberFunction = isa<CXXMemberCallExpr>(TheCall); 547 VariadicCallType CallType = getVariadicCallType(FDecl, Proto, 548 TheCall->getCallee()); 549 unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0; 550 checkCall(FDecl, TheCall->getArgs(), TheCall->getNumArgs(), NumProtoArgs, 551 IsMemberFunction, TheCall->getRParenLoc(), 552 TheCall->getCallee()->getSourceRange(), CallType); 553 554 IdentifierInfo *FnInfo = FDecl->getIdentifier(); 555 // None of the checks below are needed for functions that don't have 556 // simple names (e.g., C++ conversion functions). 557 if (!FnInfo) 558 return false; 559 560 unsigned CMId = FDecl->getMemoryFunctionKind(); 561 if (CMId == 0) 562 return false; 563 564 // Handle memory setting and copying functions. 565 if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat) 566 CheckStrlcpycatArguments(TheCall, FnInfo); 567 else if (CMId == Builtin::BIstrncat) 568 CheckStrncatArguments(TheCall, FnInfo); 569 else 570 CheckMemaccessArguments(TheCall, CMId, FnInfo); 571 572 return false; 573} 574 575bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac, 576 Expr **Args, unsigned NumArgs) { 577 VariadicCallType CallType = 578 Method->isVariadic() ? VariadicMethod : VariadicDoesNotApply; 579 580 checkCall(Method, Args, NumArgs, Method->param_size(), 581 /*IsMemberFunction=*/false, 582 lbrac, Method->getSourceRange(), CallType); 583 584 return false; 585} 586 587bool Sema::CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall, 588 const FunctionProtoType *Proto) { 589 const VarDecl *V = dyn_cast<VarDecl>(NDecl); 590 if (!V) 591 return false; 592 593 QualType Ty = V->getType(); 594 if (!Ty->isBlockPointerType()) 595 return false; 596 597 VariadicCallType CallType = 598 Proto && Proto->isVariadic() ? VariadicBlock : VariadicDoesNotApply ; 599 unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0; 600 601 checkCall(NDecl, TheCall->getArgs(), TheCall->getNumArgs(), 602 NumProtoArgs, /*IsMemberFunction=*/false, 603 TheCall->getRParenLoc(), 604 TheCall->getCallee()->getSourceRange(), CallType); 605 606 return false; 607} 608 609ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult, 610 AtomicExpr::AtomicOp Op) { 611 CallExpr *TheCall = cast<CallExpr>(TheCallResult.get()); 612 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 613 614 // All these operations take one of the following forms: 615 enum { 616 // C __c11_atomic_init(A *, C) 617 Init, 618 // C __c11_atomic_load(A *, int) 619 Load, 620 // void __atomic_load(A *, CP, int) 621 Copy, 622 // C __c11_atomic_add(A *, M, int) 623 Arithmetic, 624 // C __atomic_exchange_n(A *, CP, int) 625 Xchg, 626 // void __atomic_exchange(A *, C *, CP, int) 627 GNUXchg, 628 // bool __c11_atomic_compare_exchange_strong(A *, C *, CP, int, int) 629 C11CmpXchg, 630 // bool __atomic_compare_exchange(A *, C *, CP, bool, int, int) 631 GNUCmpXchg 632 } Form = Init; 633 const unsigned NumArgs[] = { 2, 2, 3, 3, 3, 4, 5, 6 }; 634 const unsigned NumVals[] = { 1, 0, 1, 1, 1, 2, 2, 3 }; 635 // where: 636 // C is an appropriate type, 637 // A is volatile _Atomic(C) for __c11 builtins and is C for GNU builtins, 638 // CP is C for __c11 builtins and GNU _n builtins and is C * otherwise, 639 // M is C if C is an integer, and ptrdiff_t if C is a pointer, and 640 // the int parameters are for orderings. 641 642 assert(AtomicExpr::AO__c11_atomic_init == 0 && 643 AtomicExpr::AO__c11_atomic_fetch_xor + 1 == AtomicExpr::AO__atomic_load 644 && "need to update code for modified C11 atomics"); 645 bool IsC11 = Op >= AtomicExpr::AO__c11_atomic_init && 646 Op <= AtomicExpr::AO__c11_atomic_fetch_xor; 647 bool IsN = Op == AtomicExpr::AO__atomic_load_n || 648 Op == AtomicExpr::AO__atomic_store_n || 649 Op == AtomicExpr::AO__atomic_exchange_n || 650 Op == AtomicExpr::AO__atomic_compare_exchange_n; 651 bool IsAddSub = false; 652 653 switch (Op) { 654 case AtomicExpr::AO__c11_atomic_init: 655 Form = Init; 656 break; 657 658 case AtomicExpr::AO__c11_atomic_load: 659 case AtomicExpr::AO__atomic_load_n: 660 Form = Load; 661 break; 662 663 case AtomicExpr::AO__c11_atomic_store: 664 case AtomicExpr::AO__atomic_load: 665 case AtomicExpr::AO__atomic_store: 666 case AtomicExpr::AO__atomic_store_n: 667 Form = Copy; 668 break; 669 670 case AtomicExpr::AO__c11_atomic_fetch_add: 671 case AtomicExpr::AO__c11_atomic_fetch_sub: 672 case AtomicExpr::AO__atomic_fetch_add: 673 case AtomicExpr::AO__atomic_fetch_sub: 674 case AtomicExpr::AO__atomic_add_fetch: 675 case AtomicExpr::AO__atomic_sub_fetch: 676 IsAddSub = true; 677 // Fall through. 678 case AtomicExpr::AO__c11_atomic_fetch_and: 679 case AtomicExpr::AO__c11_atomic_fetch_or: 680 case AtomicExpr::AO__c11_atomic_fetch_xor: 681 case AtomicExpr::AO__atomic_fetch_and: 682 case AtomicExpr::AO__atomic_fetch_or: 683 case AtomicExpr::AO__atomic_fetch_xor: 684 case AtomicExpr::AO__atomic_fetch_nand: 685 case AtomicExpr::AO__atomic_and_fetch: 686 case AtomicExpr::AO__atomic_or_fetch: 687 case AtomicExpr::AO__atomic_xor_fetch: 688 case AtomicExpr::AO__atomic_nand_fetch: 689 Form = Arithmetic; 690 break; 691 692 case AtomicExpr::AO__c11_atomic_exchange: 693 case AtomicExpr::AO__atomic_exchange_n: 694 Form = Xchg; 695 break; 696 697 case AtomicExpr::AO__atomic_exchange: 698 Form = GNUXchg; 699 break; 700 701 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 702 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 703 Form = C11CmpXchg; 704 break; 705 706 case AtomicExpr::AO__atomic_compare_exchange: 707 case AtomicExpr::AO__atomic_compare_exchange_n: 708 Form = GNUCmpXchg; 709 break; 710 } 711 712 // Check we have the right number of arguments. 713 if (TheCall->getNumArgs() < NumArgs[Form]) { 714 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 715 << 0 << NumArgs[Form] << TheCall->getNumArgs() 716 << TheCall->getCallee()->getSourceRange(); 717 return ExprError(); 718 } else if (TheCall->getNumArgs() > NumArgs[Form]) { 719 Diag(TheCall->getArg(NumArgs[Form])->getLocStart(), 720 diag::err_typecheck_call_too_many_args) 721 << 0 << NumArgs[Form] << TheCall->getNumArgs() 722 << TheCall->getCallee()->getSourceRange(); 723 return ExprError(); 724 } 725 726 // Inspect the first argument of the atomic operation. 727 Expr *Ptr = TheCall->getArg(0); 728 Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get(); 729 const PointerType *pointerType = Ptr->getType()->getAs<PointerType>(); 730 if (!pointerType) { 731 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 732 << Ptr->getType() << Ptr->getSourceRange(); 733 return ExprError(); 734 } 735 736 // For a __c11 builtin, this should be a pointer to an _Atomic type. 737 QualType AtomTy = pointerType->getPointeeType(); // 'A' 738 QualType ValType = AtomTy; // 'C' 739 if (IsC11) { 740 if (!AtomTy->isAtomicType()) { 741 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic) 742 << Ptr->getType() << Ptr->getSourceRange(); 743 return ExprError(); 744 } 745 ValType = AtomTy->getAs<AtomicType>()->getValueType(); 746 } 747 748 // For an arithmetic operation, the implied arithmetic must be well-formed. 749 if (Form == Arithmetic) { 750 // gcc does not enforce these rules for GNU atomics, but we do so for sanity. 751 if (IsAddSub && !ValType->isIntegerType() && !ValType->isPointerType()) { 752 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 753 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 754 return ExprError(); 755 } 756 if (!IsAddSub && !ValType->isIntegerType()) { 757 Diag(DRE->getLocStart(), diag::err_atomic_op_bitwise_needs_atomic_int) 758 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 759 return ExprError(); 760 } 761 } else if (IsN && !ValType->isIntegerType() && !ValType->isPointerType()) { 762 // For __atomic_*_n operations, the value type must be a scalar integral or 763 // pointer type which is 1, 2, 4, 8 or 16 bytes in length. 764 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 765 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 766 return ExprError(); 767 } 768 769 if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context)) { 770 // For GNU atomics, require a trivially-copyable type. This is not part of 771 // the GNU atomics specification, but we enforce it for sanity. 772 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_trivial_copy) 773 << Ptr->getType() << Ptr->getSourceRange(); 774 return ExprError(); 775 } 776 777 // FIXME: For any builtin other than a load, the ValType must not be 778 // const-qualified. 779 780 switch (ValType.getObjCLifetime()) { 781 case Qualifiers::OCL_None: 782 case Qualifiers::OCL_ExplicitNone: 783 // okay 784 break; 785 786 case Qualifiers::OCL_Weak: 787 case Qualifiers::OCL_Strong: 788 case Qualifiers::OCL_Autoreleasing: 789 // FIXME: Can this happen? By this point, ValType should be known 790 // to be trivially copyable. 791 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 792 << ValType << Ptr->getSourceRange(); 793 return ExprError(); 794 } 795 796 QualType ResultType = ValType; 797 if (Form == Copy || Form == GNUXchg || Form == Init) 798 ResultType = Context.VoidTy; 799 else if (Form == C11CmpXchg || Form == GNUCmpXchg) 800 ResultType = Context.BoolTy; 801 802 // The type of a parameter passed 'by value'. In the GNU atomics, such 803 // arguments are actually passed as pointers. 804 QualType ByValType = ValType; // 'CP' 805 if (!IsC11 && !IsN) 806 ByValType = Ptr->getType(); 807 808 // The first argument --- the pointer --- has a fixed type; we 809 // deduce the types of the rest of the arguments accordingly. Walk 810 // the remaining arguments, converting them to the deduced value type. 811 for (unsigned i = 1; i != NumArgs[Form]; ++i) { 812 QualType Ty; 813 if (i < NumVals[Form] + 1) { 814 switch (i) { 815 case 1: 816 // The second argument is the non-atomic operand. For arithmetic, this 817 // is always passed by value, and for a compare_exchange it is always 818 // passed by address. For the rest, GNU uses by-address and C11 uses 819 // by-value. 820 assert(Form != Load); 821 if (Form == Init || (Form == Arithmetic && ValType->isIntegerType())) 822 Ty = ValType; 823 else if (Form == Copy || Form == Xchg) 824 Ty = ByValType; 825 else if (Form == Arithmetic) 826 Ty = Context.getPointerDiffType(); 827 else 828 Ty = Context.getPointerType(ValType.getUnqualifiedType()); 829 break; 830 case 2: 831 // The third argument to compare_exchange / GNU exchange is a 832 // (pointer to a) desired value. 833 Ty = ByValType; 834 break; 835 case 3: 836 // The fourth argument to GNU compare_exchange is a 'weak' flag. 837 Ty = Context.BoolTy; 838 break; 839 } 840 } else { 841 // The order(s) are always converted to int. 842 Ty = Context.IntTy; 843 } 844 845 InitializedEntity Entity = 846 InitializedEntity::InitializeParameter(Context, Ty, false); 847 ExprResult Arg = TheCall->getArg(i); 848 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 849 if (Arg.isInvalid()) 850 return true; 851 TheCall->setArg(i, Arg.get()); 852 } 853 854 // Permute the arguments into a 'consistent' order. 855 SmallVector<Expr*, 5> SubExprs; 856 SubExprs.push_back(Ptr); 857 switch (Form) { 858 case Init: 859 // Note, AtomicExpr::getVal1() has a special case for this atomic. 860 SubExprs.push_back(TheCall->getArg(1)); // Val1 861 break; 862 case Load: 863 SubExprs.push_back(TheCall->getArg(1)); // Order 864 break; 865 case Copy: 866 case Arithmetic: 867 case Xchg: 868 SubExprs.push_back(TheCall->getArg(2)); // Order 869 SubExprs.push_back(TheCall->getArg(1)); // Val1 870 break; 871 case GNUXchg: 872 // Note, AtomicExpr::getVal2() has a special case for this atomic. 873 SubExprs.push_back(TheCall->getArg(3)); // Order 874 SubExprs.push_back(TheCall->getArg(1)); // Val1 875 SubExprs.push_back(TheCall->getArg(2)); // Val2 876 break; 877 case C11CmpXchg: 878 SubExprs.push_back(TheCall->getArg(3)); // Order 879 SubExprs.push_back(TheCall->getArg(1)); // Val1 880 SubExprs.push_back(TheCall->getArg(4)); // OrderFail 881 SubExprs.push_back(TheCall->getArg(2)); // Val2 882 break; 883 case GNUCmpXchg: 884 SubExprs.push_back(TheCall->getArg(4)); // Order 885 SubExprs.push_back(TheCall->getArg(1)); // Val1 886 SubExprs.push_back(TheCall->getArg(5)); // OrderFail 887 SubExprs.push_back(TheCall->getArg(2)); // Val2 888 SubExprs.push_back(TheCall->getArg(3)); // Weak 889 break; 890 } 891 892 return Owned(new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(), 893 SubExprs, ResultType, Op, 894 TheCall->getRParenLoc())); 895} 896 897 898/// checkBuiltinArgument - Given a call to a builtin function, perform 899/// normal type-checking on the given argument, updating the call in 900/// place. This is useful when a builtin function requires custom 901/// type-checking for some of its arguments but not necessarily all of 902/// them. 903/// 904/// Returns true on error. 905static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) { 906 FunctionDecl *Fn = E->getDirectCallee(); 907 assert(Fn && "builtin call without direct callee!"); 908 909 ParmVarDecl *Param = Fn->getParamDecl(ArgIndex); 910 InitializedEntity Entity = 911 InitializedEntity::InitializeParameter(S.Context, Param); 912 913 ExprResult Arg = E->getArg(0); 914 Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg); 915 if (Arg.isInvalid()) 916 return true; 917 918 E->setArg(ArgIndex, Arg.take()); 919 return false; 920} 921 922/// SemaBuiltinAtomicOverloaded - We have a call to a function like 923/// __sync_fetch_and_add, which is an overloaded function based on the pointer 924/// type of its first argument. The main ActOnCallExpr routines have already 925/// promoted the types of arguments because all of these calls are prototyped as 926/// void(...). 927/// 928/// This function goes through and does final semantic checking for these 929/// builtins, 930ExprResult 931Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) { 932 CallExpr *TheCall = (CallExpr *)TheCallResult.get(); 933 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 934 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 935 936 // Ensure that we have at least one argument to do type inference from. 937 if (TheCall->getNumArgs() < 1) { 938 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 939 << 0 << 1 << TheCall->getNumArgs() 940 << TheCall->getCallee()->getSourceRange(); 941 return ExprError(); 942 } 943 944 // Inspect the first argument of the atomic builtin. This should always be 945 // a pointer type, whose element is an integral scalar or pointer type. 946 // Because it is a pointer type, we don't have to worry about any implicit 947 // casts here. 948 // FIXME: We don't allow floating point scalars as input. 949 Expr *FirstArg = TheCall->getArg(0); 950 ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg); 951 if (FirstArgResult.isInvalid()) 952 return ExprError(); 953 FirstArg = FirstArgResult.take(); 954 TheCall->setArg(0, FirstArg); 955 956 const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>(); 957 if (!pointerType) { 958 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 959 << FirstArg->getType() << FirstArg->getSourceRange(); 960 return ExprError(); 961 } 962 963 QualType ValType = pointerType->getPointeeType(); 964 if (!ValType->isIntegerType() && !ValType->isAnyPointerType() && 965 !ValType->isBlockPointerType()) { 966 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr) 967 << FirstArg->getType() << FirstArg->getSourceRange(); 968 return ExprError(); 969 } 970 971 switch (ValType.getObjCLifetime()) { 972 case Qualifiers::OCL_None: 973 case Qualifiers::OCL_ExplicitNone: 974 // okay 975 break; 976 977 case Qualifiers::OCL_Weak: 978 case Qualifiers::OCL_Strong: 979 case Qualifiers::OCL_Autoreleasing: 980 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 981 << ValType << FirstArg->getSourceRange(); 982 return ExprError(); 983 } 984 985 // Strip any qualifiers off ValType. 986 ValType = ValType.getUnqualifiedType(); 987 988 // The majority of builtins return a value, but a few have special return 989 // types, so allow them to override appropriately below. 990 QualType ResultType = ValType; 991 992 // We need to figure out which concrete builtin this maps onto. For example, 993 // __sync_fetch_and_add with a 2 byte object turns into 994 // __sync_fetch_and_add_2. 995#define BUILTIN_ROW(x) \ 996 { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \ 997 Builtin::BI##x##_8, Builtin::BI##x##_16 } 998 999 static const unsigned BuiltinIndices[][5] = { 1000 BUILTIN_ROW(__sync_fetch_and_add), 1001 BUILTIN_ROW(__sync_fetch_and_sub), 1002 BUILTIN_ROW(__sync_fetch_and_or), 1003 BUILTIN_ROW(__sync_fetch_and_and), 1004 BUILTIN_ROW(__sync_fetch_and_xor), 1005 1006 BUILTIN_ROW(__sync_add_and_fetch), 1007 BUILTIN_ROW(__sync_sub_and_fetch), 1008 BUILTIN_ROW(__sync_and_and_fetch), 1009 BUILTIN_ROW(__sync_or_and_fetch), 1010 BUILTIN_ROW(__sync_xor_and_fetch), 1011 1012 BUILTIN_ROW(__sync_val_compare_and_swap), 1013 BUILTIN_ROW(__sync_bool_compare_and_swap), 1014 BUILTIN_ROW(__sync_lock_test_and_set), 1015 BUILTIN_ROW(__sync_lock_release), 1016 BUILTIN_ROW(__sync_swap) 1017 }; 1018#undef BUILTIN_ROW 1019 1020 // Determine the index of the size. 1021 unsigned SizeIndex; 1022 switch (Context.getTypeSizeInChars(ValType).getQuantity()) { 1023 case 1: SizeIndex = 0; break; 1024 case 2: SizeIndex = 1; break; 1025 case 4: SizeIndex = 2; break; 1026 case 8: SizeIndex = 3; break; 1027 case 16: SizeIndex = 4; break; 1028 default: 1029 Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size) 1030 << FirstArg->getType() << FirstArg->getSourceRange(); 1031 return ExprError(); 1032 } 1033 1034 // Each of these builtins has one pointer argument, followed by some number of 1035 // values (0, 1 or 2) followed by a potentially empty varags list of stuff 1036 // that we ignore. Find out which row of BuiltinIndices to read from as well 1037 // as the number of fixed args. 1038 unsigned BuiltinID = FDecl->getBuiltinID(); 1039 unsigned BuiltinIndex, NumFixed = 1; 1040 switch (BuiltinID) { 1041 default: llvm_unreachable("Unknown overloaded atomic builtin!"); 1042 case Builtin::BI__sync_fetch_and_add: 1043 case Builtin::BI__sync_fetch_and_add_1: 1044 case Builtin::BI__sync_fetch_and_add_2: 1045 case Builtin::BI__sync_fetch_and_add_4: 1046 case Builtin::BI__sync_fetch_and_add_8: 1047 case Builtin::BI__sync_fetch_and_add_16: 1048 BuiltinIndex = 0; 1049 break; 1050 1051 case Builtin::BI__sync_fetch_and_sub: 1052 case Builtin::BI__sync_fetch_and_sub_1: 1053 case Builtin::BI__sync_fetch_and_sub_2: 1054 case Builtin::BI__sync_fetch_and_sub_4: 1055 case Builtin::BI__sync_fetch_and_sub_8: 1056 case Builtin::BI__sync_fetch_and_sub_16: 1057 BuiltinIndex = 1; 1058 break; 1059 1060 case Builtin::BI__sync_fetch_and_or: 1061 case Builtin::BI__sync_fetch_and_or_1: 1062 case Builtin::BI__sync_fetch_and_or_2: 1063 case Builtin::BI__sync_fetch_and_or_4: 1064 case Builtin::BI__sync_fetch_and_or_8: 1065 case Builtin::BI__sync_fetch_and_or_16: 1066 BuiltinIndex = 2; 1067 break; 1068 1069 case Builtin::BI__sync_fetch_and_and: 1070 case Builtin::BI__sync_fetch_and_and_1: 1071 case Builtin::BI__sync_fetch_and_and_2: 1072 case Builtin::BI__sync_fetch_and_and_4: 1073 case Builtin::BI__sync_fetch_and_and_8: 1074 case Builtin::BI__sync_fetch_and_and_16: 1075 BuiltinIndex = 3; 1076 break; 1077 1078 case Builtin::BI__sync_fetch_and_xor: 1079 case Builtin::BI__sync_fetch_and_xor_1: 1080 case Builtin::BI__sync_fetch_and_xor_2: 1081 case Builtin::BI__sync_fetch_and_xor_4: 1082 case Builtin::BI__sync_fetch_and_xor_8: 1083 case Builtin::BI__sync_fetch_and_xor_16: 1084 BuiltinIndex = 4; 1085 break; 1086 1087 case Builtin::BI__sync_add_and_fetch: 1088 case Builtin::BI__sync_add_and_fetch_1: 1089 case Builtin::BI__sync_add_and_fetch_2: 1090 case Builtin::BI__sync_add_and_fetch_4: 1091 case Builtin::BI__sync_add_and_fetch_8: 1092 case Builtin::BI__sync_add_and_fetch_16: 1093 BuiltinIndex = 5; 1094 break; 1095 1096 case Builtin::BI__sync_sub_and_fetch: 1097 case Builtin::BI__sync_sub_and_fetch_1: 1098 case Builtin::BI__sync_sub_and_fetch_2: 1099 case Builtin::BI__sync_sub_and_fetch_4: 1100 case Builtin::BI__sync_sub_and_fetch_8: 1101 case Builtin::BI__sync_sub_and_fetch_16: 1102 BuiltinIndex = 6; 1103 break; 1104 1105 case Builtin::BI__sync_and_and_fetch: 1106 case Builtin::BI__sync_and_and_fetch_1: 1107 case Builtin::BI__sync_and_and_fetch_2: 1108 case Builtin::BI__sync_and_and_fetch_4: 1109 case Builtin::BI__sync_and_and_fetch_8: 1110 case Builtin::BI__sync_and_and_fetch_16: 1111 BuiltinIndex = 7; 1112 break; 1113 1114 case Builtin::BI__sync_or_and_fetch: 1115 case Builtin::BI__sync_or_and_fetch_1: 1116 case Builtin::BI__sync_or_and_fetch_2: 1117 case Builtin::BI__sync_or_and_fetch_4: 1118 case Builtin::BI__sync_or_and_fetch_8: 1119 case Builtin::BI__sync_or_and_fetch_16: 1120 BuiltinIndex = 8; 1121 break; 1122 1123 case Builtin::BI__sync_xor_and_fetch: 1124 case Builtin::BI__sync_xor_and_fetch_1: 1125 case Builtin::BI__sync_xor_and_fetch_2: 1126 case Builtin::BI__sync_xor_and_fetch_4: 1127 case Builtin::BI__sync_xor_and_fetch_8: 1128 case Builtin::BI__sync_xor_and_fetch_16: 1129 BuiltinIndex = 9; 1130 break; 1131 1132 case Builtin::BI__sync_val_compare_and_swap: 1133 case Builtin::BI__sync_val_compare_and_swap_1: 1134 case Builtin::BI__sync_val_compare_and_swap_2: 1135 case Builtin::BI__sync_val_compare_and_swap_4: 1136 case Builtin::BI__sync_val_compare_and_swap_8: 1137 case Builtin::BI__sync_val_compare_and_swap_16: 1138 BuiltinIndex = 10; 1139 NumFixed = 2; 1140 break; 1141 1142 case Builtin::BI__sync_bool_compare_and_swap: 1143 case Builtin::BI__sync_bool_compare_and_swap_1: 1144 case Builtin::BI__sync_bool_compare_and_swap_2: 1145 case Builtin::BI__sync_bool_compare_and_swap_4: 1146 case Builtin::BI__sync_bool_compare_and_swap_8: 1147 case Builtin::BI__sync_bool_compare_and_swap_16: 1148 BuiltinIndex = 11; 1149 NumFixed = 2; 1150 ResultType = Context.BoolTy; 1151 break; 1152 1153 case Builtin::BI__sync_lock_test_and_set: 1154 case Builtin::BI__sync_lock_test_and_set_1: 1155 case Builtin::BI__sync_lock_test_and_set_2: 1156 case Builtin::BI__sync_lock_test_and_set_4: 1157 case Builtin::BI__sync_lock_test_and_set_8: 1158 case Builtin::BI__sync_lock_test_and_set_16: 1159 BuiltinIndex = 12; 1160 break; 1161 1162 case Builtin::BI__sync_lock_release: 1163 case Builtin::BI__sync_lock_release_1: 1164 case Builtin::BI__sync_lock_release_2: 1165 case Builtin::BI__sync_lock_release_4: 1166 case Builtin::BI__sync_lock_release_8: 1167 case Builtin::BI__sync_lock_release_16: 1168 BuiltinIndex = 13; 1169 NumFixed = 0; 1170 ResultType = Context.VoidTy; 1171 break; 1172 1173 case Builtin::BI__sync_swap: 1174 case Builtin::BI__sync_swap_1: 1175 case Builtin::BI__sync_swap_2: 1176 case Builtin::BI__sync_swap_4: 1177 case Builtin::BI__sync_swap_8: 1178 case Builtin::BI__sync_swap_16: 1179 BuiltinIndex = 14; 1180 break; 1181 } 1182 1183 // Now that we know how many fixed arguments we expect, first check that we 1184 // have at least that many. 1185 if (TheCall->getNumArgs() < 1+NumFixed) { 1186 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 1187 << 0 << 1+NumFixed << TheCall->getNumArgs() 1188 << TheCall->getCallee()->getSourceRange(); 1189 return ExprError(); 1190 } 1191 1192 // Get the decl for the concrete builtin from this, we can tell what the 1193 // concrete integer type we should convert to is. 1194 unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex]; 1195 const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID); 1196 IdentifierInfo *NewBuiltinII = PP.getIdentifierInfo(NewBuiltinName); 1197 FunctionDecl *NewBuiltinDecl = 1198 cast<FunctionDecl>(LazilyCreateBuiltin(NewBuiltinII, NewBuiltinID, 1199 TUScope, false, DRE->getLocStart())); 1200 1201 // The first argument --- the pointer --- has a fixed type; we 1202 // deduce the types of the rest of the arguments accordingly. Walk 1203 // the remaining arguments, converting them to the deduced value type. 1204 for (unsigned i = 0; i != NumFixed; ++i) { 1205 ExprResult Arg = TheCall->getArg(i+1); 1206 1207 // GCC does an implicit conversion to the pointer or integer ValType. This 1208 // can fail in some cases (1i -> int**), check for this error case now. 1209 // Initialize the argument. 1210 InitializedEntity Entity = InitializedEntity::InitializeParameter(Context, 1211 ValType, /*consume*/ false); 1212 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 1213 if (Arg.isInvalid()) 1214 return ExprError(); 1215 1216 // Okay, we have something that *can* be converted to the right type. Check 1217 // to see if there is a potentially weird extension going on here. This can 1218 // happen when you do an atomic operation on something like an char* and 1219 // pass in 42. The 42 gets converted to char. This is even more strange 1220 // for things like 45.123 -> char, etc. 1221 // FIXME: Do this check. 1222 TheCall->setArg(i+1, Arg.take()); 1223 } 1224 1225 ASTContext& Context = this->getASTContext(); 1226 1227 // Create a new DeclRefExpr to refer to the new decl. 1228 DeclRefExpr* NewDRE = DeclRefExpr::Create( 1229 Context, 1230 DRE->getQualifierLoc(), 1231 SourceLocation(), 1232 NewBuiltinDecl, 1233 /*enclosing*/ false, 1234 DRE->getLocation(), 1235 Context.BuiltinFnTy, 1236 DRE->getValueKind()); 1237 1238 // Set the callee in the CallExpr. 1239 // FIXME: This loses syntactic information. 1240 QualType CalleePtrTy = Context.getPointerType(NewBuiltinDecl->getType()); 1241 ExprResult PromotedCall = ImpCastExprToType(NewDRE, CalleePtrTy, 1242 CK_BuiltinFnToFnPtr); 1243 TheCall->setCallee(PromotedCall.take()); 1244 1245 // Change the result type of the call to match the original value type. This 1246 // is arbitrary, but the codegen for these builtins ins design to handle it 1247 // gracefully. 1248 TheCall->setType(ResultType); 1249 1250 return TheCallResult; 1251} 1252 1253/// CheckObjCString - Checks that the argument to the builtin 1254/// CFString constructor is correct 1255/// Note: It might also make sense to do the UTF-16 conversion here (would 1256/// simplify the backend). 1257bool Sema::CheckObjCString(Expr *Arg) { 1258 Arg = Arg->IgnoreParenCasts(); 1259 StringLiteral *Literal = dyn_cast<StringLiteral>(Arg); 1260 1261 if (!Literal || !Literal->isAscii()) { 1262 Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant) 1263 << Arg->getSourceRange(); 1264 return true; 1265 } 1266 1267 if (Literal->containsNonAsciiOrNull()) { 1268 StringRef String = Literal->getString(); 1269 unsigned NumBytes = String.size(); 1270 SmallVector<UTF16, 128> ToBuf(NumBytes); 1271 const UTF8 *FromPtr = (const UTF8 *)String.data(); 1272 UTF16 *ToPtr = &ToBuf[0]; 1273 1274 ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, 1275 &ToPtr, ToPtr + NumBytes, 1276 strictConversion); 1277 // Check for conversion failure. 1278 if (Result != conversionOK) 1279 Diag(Arg->getLocStart(), 1280 diag::warn_cfstring_truncated) << Arg->getSourceRange(); 1281 } 1282 return false; 1283} 1284 1285/// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity. 1286/// Emit an error and return true on failure, return false on success. 1287bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) { 1288 Expr *Fn = TheCall->getCallee(); 1289 if (TheCall->getNumArgs() > 2) { 1290 Diag(TheCall->getArg(2)->getLocStart(), 1291 diag::err_typecheck_call_too_many_args) 1292 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1293 << Fn->getSourceRange() 1294 << SourceRange(TheCall->getArg(2)->getLocStart(), 1295 (*(TheCall->arg_end()-1))->getLocEnd()); 1296 return true; 1297 } 1298 1299 if (TheCall->getNumArgs() < 2) { 1300 return Diag(TheCall->getLocEnd(), 1301 diag::err_typecheck_call_too_few_args_at_least) 1302 << 0 /*function call*/ << 2 << TheCall->getNumArgs(); 1303 } 1304 1305 // Type-check the first argument normally. 1306 if (checkBuiltinArgument(*this, TheCall, 0)) 1307 return true; 1308 1309 // Determine whether the current function is variadic or not. 1310 BlockScopeInfo *CurBlock = getCurBlock(); 1311 bool isVariadic; 1312 if (CurBlock) 1313 isVariadic = CurBlock->TheDecl->isVariadic(); 1314 else if (FunctionDecl *FD = getCurFunctionDecl()) 1315 isVariadic = FD->isVariadic(); 1316 else 1317 isVariadic = getCurMethodDecl()->isVariadic(); 1318 1319 if (!isVariadic) { 1320 Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function); 1321 return true; 1322 } 1323 1324 // Verify that the second argument to the builtin is the last argument of the 1325 // current function or method. 1326 bool SecondArgIsLastNamedArgument = false; 1327 const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts(); 1328 1329 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) { 1330 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) { 1331 // FIXME: This isn't correct for methods (results in bogus warning). 1332 // Get the last formal in the current function. 1333 const ParmVarDecl *LastArg; 1334 if (CurBlock) 1335 LastArg = *(CurBlock->TheDecl->param_end()-1); 1336 else if (FunctionDecl *FD = getCurFunctionDecl()) 1337 LastArg = *(FD->param_end()-1); 1338 else 1339 LastArg = *(getCurMethodDecl()->param_end()-1); 1340 SecondArgIsLastNamedArgument = PV == LastArg; 1341 } 1342 } 1343 1344 if (!SecondArgIsLastNamedArgument) 1345 Diag(TheCall->getArg(1)->getLocStart(), 1346 diag::warn_second_parameter_of_va_start_not_last_named_argument); 1347 return false; 1348} 1349 1350/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and 1351/// friends. This is declared to take (...), so we have to check everything. 1352bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) { 1353 if (TheCall->getNumArgs() < 2) 1354 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 1355 << 0 << 2 << TheCall->getNumArgs()/*function call*/; 1356 if (TheCall->getNumArgs() > 2) 1357 return Diag(TheCall->getArg(2)->getLocStart(), 1358 diag::err_typecheck_call_too_many_args) 1359 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1360 << SourceRange(TheCall->getArg(2)->getLocStart(), 1361 (*(TheCall->arg_end()-1))->getLocEnd()); 1362 1363 ExprResult OrigArg0 = TheCall->getArg(0); 1364 ExprResult OrigArg1 = TheCall->getArg(1); 1365 1366 // Do standard promotions between the two arguments, returning their common 1367 // type. 1368 QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false); 1369 if (OrigArg0.isInvalid() || OrigArg1.isInvalid()) 1370 return true; 1371 1372 // Make sure any conversions are pushed back into the call; this is 1373 // type safe since unordered compare builtins are declared as "_Bool 1374 // foo(...)". 1375 TheCall->setArg(0, OrigArg0.get()); 1376 TheCall->setArg(1, OrigArg1.get()); 1377 1378 if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent()) 1379 return false; 1380 1381 // If the common type isn't a real floating type, then the arguments were 1382 // invalid for this operation. 1383 if (Res.isNull() || !Res->isRealFloatingType()) 1384 return Diag(OrigArg0.get()->getLocStart(), 1385 diag::err_typecheck_call_invalid_ordered_compare) 1386 << OrigArg0.get()->getType() << OrigArg1.get()->getType() 1387 << SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd()); 1388 1389 return false; 1390} 1391 1392/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like 1393/// __builtin_isnan and friends. This is declared to take (...), so we have 1394/// to check everything. We expect the last argument to be a floating point 1395/// value. 1396bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) { 1397 if (TheCall->getNumArgs() < NumArgs) 1398 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 1399 << 0 << NumArgs << TheCall->getNumArgs()/*function call*/; 1400 if (TheCall->getNumArgs() > NumArgs) 1401 return Diag(TheCall->getArg(NumArgs)->getLocStart(), 1402 diag::err_typecheck_call_too_many_args) 1403 << 0 /*function call*/ << NumArgs << TheCall->getNumArgs() 1404 << SourceRange(TheCall->getArg(NumArgs)->getLocStart(), 1405 (*(TheCall->arg_end()-1))->getLocEnd()); 1406 1407 Expr *OrigArg = TheCall->getArg(NumArgs-1); 1408 1409 if (OrigArg->isTypeDependent()) 1410 return false; 1411 1412 // This operation requires a non-_Complex floating-point number. 1413 if (!OrigArg->getType()->isRealFloatingType()) 1414 return Diag(OrigArg->getLocStart(), 1415 diag::err_typecheck_call_invalid_unary_fp) 1416 << OrigArg->getType() << OrigArg->getSourceRange(); 1417 1418 // If this is an implicit conversion from float -> double, remove it. 1419 if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) { 1420 Expr *CastArg = Cast->getSubExpr(); 1421 if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) { 1422 assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) && 1423 "promotion from float to double is the only expected cast here"); 1424 Cast->setSubExpr(0); 1425 TheCall->setArg(NumArgs-1, CastArg); 1426 } 1427 } 1428 1429 return false; 1430} 1431 1432/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector. 1433// This is declared to take (...), so we have to check everything. 1434ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) { 1435 if (TheCall->getNumArgs() < 2) 1436 return ExprError(Diag(TheCall->getLocEnd(), 1437 diag::err_typecheck_call_too_few_args_at_least) 1438 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1439 << TheCall->getSourceRange()); 1440 1441 // Determine which of the following types of shufflevector we're checking: 1442 // 1) unary, vector mask: (lhs, mask) 1443 // 2) binary, vector mask: (lhs, rhs, mask) 1444 // 3) binary, scalar mask: (lhs, rhs, index, ..., index) 1445 QualType resType = TheCall->getArg(0)->getType(); 1446 unsigned numElements = 0; 1447 1448 if (!TheCall->getArg(0)->isTypeDependent() && 1449 !TheCall->getArg(1)->isTypeDependent()) { 1450 QualType LHSType = TheCall->getArg(0)->getType(); 1451 QualType RHSType = TheCall->getArg(1)->getType(); 1452 1453 if (!LHSType->isVectorType() || !RHSType->isVectorType()) { 1454 Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector) 1455 << SourceRange(TheCall->getArg(0)->getLocStart(), 1456 TheCall->getArg(1)->getLocEnd()); 1457 return ExprError(); 1458 } 1459 1460 numElements = LHSType->getAs<VectorType>()->getNumElements(); 1461 unsigned numResElements = TheCall->getNumArgs() - 2; 1462 1463 // Check to see if we have a call with 2 vector arguments, the unary shuffle 1464 // with mask. If so, verify that RHS is an integer vector type with the 1465 // same number of elts as lhs. 1466 if (TheCall->getNumArgs() == 2) { 1467 if (!RHSType->hasIntegerRepresentation() || 1468 RHSType->getAs<VectorType>()->getNumElements() != numElements) 1469 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 1470 << SourceRange(TheCall->getArg(1)->getLocStart(), 1471 TheCall->getArg(1)->getLocEnd()); 1472 numResElements = numElements; 1473 } 1474 else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) { 1475 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 1476 << SourceRange(TheCall->getArg(0)->getLocStart(), 1477 TheCall->getArg(1)->getLocEnd()); 1478 return ExprError(); 1479 } else if (numElements != numResElements) { 1480 QualType eltType = LHSType->getAs<VectorType>()->getElementType(); 1481 resType = Context.getVectorType(eltType, numResElements, 1482 VectorType::GenericVector); 1483 } 1484 } 1485 1486 for (unsigned i = 2; i < TheCall->getNumArgs(); i++) { 1487 if (TheCall->getArg(i)->isTypeDependent() || 1488 TheCall->getArg(i)->isValueDependent()) 1489 continue; 1490 1491 llvm::APSInt Result(32); 1492 if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context)) 1493 return ExprError(Diag(TheCall->getLocStart(), 1494 diag::err_shufflevector_nonconstant_argument) 1495 << TheCall->getArg(i)->getSourceRange()); 1496 1497 if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2) 1498 return ExprError(Diag(TheCall->getLocStart(), 1499 diag::err_shufflevector_argument_too_large) 1500 << TheCall->getArg(i)->getSourceRange()); 1501 } 1502 1503 SmallVector<Expr*, 32> exprs; 1504 1505 for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) { 1506 exprs.push_back(TheCall->getArg(i)); 1507 TheCall->setArg(i, 0); 1508 } 1509 1510 return Owned(new (Context) ShuffleVectorExpr(Context, exprs, resType, 1511 TheCall->getCallee()->getLocStart(), 1512 TheCall->getRParenLoc())); 1513} 1514 1515/// SemaBuiltinPrefetch - Handle __builtin_prefetch. 1516// This is declared to take (const void*, ...) and can take two 1517// optional constant int args. 1518bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) { 1519 unsigned NumArgs = TheCall->getNumArgs(); 1520 1521 if (NumArgs > 3) 1522 return Diag(TheCall->getLocEnd(), 1523 diag::err_typecheck_call_too_many_args_at_most) 1524 << 0 /*function call*/ << 3 << NumArgs 1525 << TheCall->getSourceRange(); 1526 1527 // Argument 0 is checked for us and the remaining arguments must be 1528 // constant integers. 1529 for (unsigned i = 1; i != NumArgs; ++i) { 1530 Expr *Arg = TheCall->getArg(i); 1531 1532 // We can't check the value of a dependent argument. 1533 if (Arg->isTypeDependent() || Arg->isValueDependent()) 1534 continue; 1535 1536 llvm::APSInt Result; 1537 if (SemaBuiltinConstantArg(TheCall, i, Result)) 1538 return true; 1539 1540 // FIXME: gcc issues a warning and rewrites these to 0. These 1541 // seems especially odd for the third argument since the default 1542 // is 3. 1543 if (i == 1) { 1544 if (Result.getLimitedValue() > 1) 1545 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1546 << "0" << "1" << Arg->getSourceRange(); 1547 } else { 1548 if (Result.getLimitedValue() > 3) 1549 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1550 << "0" << "3" << Arg->getSourceRange(); 1551 } 1552 } 1553 1554 return false; 1555} 1556 1557/// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr 1558/// TheCall is a constant expression. 1559bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum, 1560 llvm::APSInt &Result) { 1561 Expr *Arg = TheCall->getArg(ArgNum); 1562 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 1563 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 1564 1565 if (Arg->isTypeDependent() || Arg->isValueDependent()) return false; 1566 1567 if (!Arg->isIntegerConstantExpr(Result, Context)) 1568 return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type) 1569 << FDecl->getDeclName() << Arg->getSourceRange(); 1570 1571 return false; 1572} 1573 1574/// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr, 1575/// int type). This simply type checks that type is one of the defined 1576/// constants (0-3). 1577// For compatibility check 0-3, llvm only handles 0 and 2. 1578bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) { 1579 llvm::APSInt Result; 1580 1581 // We can't check the value of a dependent argument. 1582 if (TheCall->getArg(1)->isTypeDependent() || 1583 TheCall->getArg(1)->isValueDependent()) 1584 return false; 1585 1586 // Check constant-ness first. 1587 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 1588 return true; 1589 1590 Expr *Arg = TheCall->getArg(1); 1591 if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) { 1592 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1593 << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 1594 } 1595 1596 return false; 1597} 1598 1599/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val). 1600/// This checks that val is a constant 1. 1601bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) { 1602 Expr *Arg = TheCall->getArg(1); 1603 llvm::APSInt Result; 1604 1605 // TODO: This is less than ideal. Overload this to take a value. 1606 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 1607 return true; 1608 1609 if (Result != 1) 1610 return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val) 1611 << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 1612 1613 return false; 1614} 1615 1616// Determine if an expression is a string literal or constant string. 1617// If this function returns false on the arguments to a function expecting a 1618// format string, we will usually need to emit a warning. 1619// True string literals are then checked by CheckFormatString. 1620Sema::StringLiteralCheckType 1621Sema::checkFormatStringExpr(const Expr *E, Expr **Args, 1622 unsigned NumArgs, bool HasVAListArg, 1623 unsigned format_idx, unsigned firstDataArg, 1624 FormatStringType Type, VariadicCallType CallType, 1625 bool inFunctionCall) { 1626 tryAgain: 1627 if (E->isTypeDependent() || E->isValueDependent()) 1628 return SLCT_NotALiteral; 1629 1630 E = E->IgnoreParenCasts(); 1631 1632 if (E->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull)) 1633 // Technically -Wformat-nonliteral does not warn about this case. 1634 // The behavior of printf and friends in this case is implementation 1635 // dependent. Ideally if the format string cannot be null then 1636 // it should have a 'nonnull' attribute in the function prototype. 1637 return SLCT_CheckedLiteral; 1638 1639 switch (E->getStmtClass()) { 1640 case Stmt::BinaryConditionalOperatorClass: 1641 case Stmt::ConditionalOperatorClass: { 1642 // The expression is a literal if both sub-expressions were, and it was 1643 // completely checked only if both sub-expressions were checked. 1644 const AbstractConditionalOperator *C = 1645 cast<AbstractConditionalOperator>(E); 1646 StringLiteralCheckType Left = 1647 checkFormatStringExpr(C->getTrueExpr(), Args, NumArgs, 1648 HasVAListArg, format_idx, firstDataArg, 1649 Type, CallType, inFunctionCall); 1650 if (Left == SLCT_NotALiteral) 1651 return SLCT_NotALiteral; 1652 StringLiteralCheckType Right = 1653 checkFormatStringExpr(C->getFalseExpr(), Args, NumArgs, 1654 HasVAListArg, format_idx, firstDataArg, 1655 Type, CallType, inFunctionCall); 1656 return Left < Right ? Left : Right; 1657 } 1658 1659 case Stmt::ImplicitCastExprClass: { 1660 E = cast<ImplicitCastExpr>(E)->getSubExpr(); 1661 goto tryAgain; 1662 } 1663 1664 case Stmt::OpaqueValueExprClass: 1665 if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) { 1666 E = src; 1667 goto tryAgain; 1668 } 1669 return SLCT_NotALiteral; 1670 1671 case Stmt::PredefinedExprClass: 1672 // While __func__, etc., are technically not string literals, they 1673 // cannot contain format specifiers and thus are not a security 1674 // liability. 1675 return SLCT_UncheckedLiteral; 1676 1677 case Stmt::DeclRefExprClass: { 1678 const DeclRefExpr *DR = cast<DeclRefExpr>(E); 1679 1680 // As an exception, do not flag errors for variables binding to 1681 // const string literals. 1682 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) { 1683 bool isConstant = false; 1684 QualType T = DR->getType(); 1685 1686 if (const ArrayType *AT = Context.getAsArrayType(T)) { 1687 isConstant = AT->getElementType().isConstant(Context); 1688 } else if (const PointerType *PT = T->getAs<PointerType>()) { 1689 isConstant = T.isConstant(Context) && 1690 PT->getPointeeType().isConstant(Context); 1691 } else if (T->isObjCObjectPointerType()) { 1692 // In ObjC, there is usually no "const ObjectPointer" type, 1693 // so don't check if the pointee type is constant. 1694 isConstant = T.isConstant(Context); 1695 } 1696 1697 if (isConstant) { 1698 if (const Expr *Init = VD->getAnyInitializer()) { 1699 // Look through initializers like const char c[] = { "foo" } 1700 if (const InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) { 1701 if (InitList->isStringLiteralInit()) 1702 Init = InitList->getInit(0)->IgnoreParenImpCasts(); 1703 } 1704 return checkFormatStringExpr(Init, Args, NumArgs, 1705 HasVAListArg, format_idx, 1706 firstDataArg, Type, CallType, 1707 /*inFunctionCall*/false); 1708 } 1709 } 1710 1711 // For vprintf* functions (i.e., HasVAListArg==true), we add a 1712 // special check to see if the format string is a function parameter 1713 // of the function calling the printf function. If the function 1714 // has an attribute indicating it is a printf-like function, then we 1715 // should suppress warnings concerning non-literals being used in a call 1716 // to a vprintf function. For example: 1717 // 1718 // void 1719 // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){ 1720 // va_list ap; 1721 // va_start(ap, fmt); 1722 // vprintf(fmt, ap); // Do NOT emit a warning about "fmt". 1723 // ... 1724 // 1725 if (HasVAListArg) { 1726 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(VD)) { 1727 if (const NamedDecl *ND = dyn_cast<NamedDecl>(PV->getDeclContext())) { 1728 int PVIndex = PV->getFunctionScopeIndex() + 1; 1729 for (specific_attr_iterator<FormatAttr> 1730 i = ND->specific_attr_begin<FormatAttr>(), 1731 e = ND->specific_attr_end<FormatAttr>(); i != e ; ++i) { 1732 FormatAttr *PVFormat = *i; 1733 // adjust for implicit parameter 1734 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 1735 if (MD->isInstance()) 1736 ++PVIndex; 1737 // We also check if the formats are compatible. 1738 // We can't pass a 'scanf' string to a 'printf' function. 1739 if (PVIndex == PVFormat->getFormatIdx() && 1740 Type == GetFormatStringType(PVFormat)) 1741 return SLCT_UncheckedLiteral; 1742 } 1743 } 1744 } 1745 } 1746 } 1747 1748 return SLCT_NotALiteral; 1749 } 1750 1751 case Stmt::CallExprClass: 1752 case Stmt::CXXMemberCallExprClass: { 1753 const CallExpr *CE = cast<CallExpr>(E); 1754 if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) { 1755 if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) { 1756 unsigned ArgIndex = FA->getFormatIdx(); 1757 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 1758 if (MD->isInstance()) 1759 --ArgIndex; 1760 const Expr *Arg = CE->getArg(ArgIndex - 1); 1761 1762 return checkFormatStringExpr(Arg, Args, NumArgs, 1763 HasVAListArg, format_idx, firstDataArg, 1764 Type, CallType, inFunctionCall); 1765 } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) { 1766 unsigned BuiltinID = FD->getBuiltinID(); 1767 if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString || 1768 BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) { 1769 const Expr *Arg = CE->getArg(0); 1770 return checkFormatStringExpr(Arg, Args, NumArgs, 1771 HasVAListArg, format_idx, 1772 firstDataArg, Type, CallType, 1773 inFunctionCall); 1774 } 1775 } 1776 } 1777 1778 return SLCT_NotALiteral; 1779 } 1780 case Stmt::ObjCStringLiteralClass: 1781 case Stmt::StringLiteralClass: { 1782 const StringLiteral *StrE = NULL; 1783 1784 if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E)) 1785 StrE = ObjCFExpr->getString(); 1786 else 1787 StrE = cast<StringLiteral>(E); 1788 1789 if (StrE) { 1790 CheckFormatString(StrE, E, Args, NumArgs, HasVAListArg, format_idx, 1791 firstDataArg, Type, inFunctionCall, CallType); 1792 return SLCT_CheckedLiteral; 1793 } 1794 1795 return SLCT_NotALiteral; 1796 } 1797 1798 default: 1799 return SLCT_NotALiteral; 1800 } 1801} 1802 1803void 1804Sema::CheckNonNullArguments(const NonNullAttr *NonNull, 1805 const Expr * const *ExprArgs, 1806 SourceLocation CallSiteLoc) { 1807 for (NonNullAttr::args_iterator i = NonNull->args_begin(), 1808 e = NonNull->args_end(); 1809 i != e; ++i) { 1810 const Expr *ArgExpr = ExprArgs[*i]; 1811 if (ArgExpr->isNullPointerConstant(Context, 1812 Expr::NPC_ValueDependentIsNotNull)) 1813 Diag(CallSiteLoc, diag::warn_null_arg) << ArgExpr->getSourceRange(); 1814 } 1815} 1816 1817Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) { 1818 return llvm::StringSwitch<FormatStringType>(Format->getType()) 1819 .Case("scanf", FST_Scanf) 1820 .Cases("printf", "printf0", FST_Printf) 1821 .Cases("NSString", "CFString", FST_NSString) 1822 .Case("strftime", FST_Strftime) 1823 .Case("strfmon", FST_Strfmon) 1824 .Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf) 1825 .Default(FST_Unknown); 1826} 1827 1828/// CheckFormatArguments - Check calls to printf and scanf (and similar 1829/// functions) for correct use of format strings. 1830/// Returns true if a format string has been fully checked. 1831bool Sema::CheckFormatArguments(const FormatAttr *Format, Expr **Args, 1832 unsigned NumArgs, bool IsCXXMember, 1833 VariadicCallType CallType, 1834 SourceLocation Loc, SourceRange Range) { 1835 FormatStringInfo FSI; 1836 if (getFormatStringInfo(Format, IsCXXMember, &FSI)) 1837 return CheckFormatArguments(Args, NumArgs, FSI.HasVAListArg, FSI.FormatIdx, 1838 FSI.FirstDataArg, GetFormatStringType(Format), 1839 CallType, Loc, Range); 1840 return false; 1841} 1842 1843bool Sema::CheckFormatArguments(Expr **Args, unsigned NumArgs, 1844 bool HasVAListArg, unsigned format_idx, 1845 unsigned firstDataArg, FormatStringType Type, 1846 VariadicCallType CallType, 1847 SourceLocation Loc, SourceRange Range) { 1848 // CHECK: printf/scanf-like function is called with no format string. 1849 if (format_idx >= NumArgs) { 1850 Diag(Loc, diag::warn_missing_format_string) << Range; 1851 return false; 1852 } 1853 1854 const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts(); 1855 1856 // CHECK: format string is not a string literal. 1857 // 1858 // Dynamically generated format strings are difficult to 1859 // automatically vet at compile time. Requiring that format strings 1860 // are string literals: (1) permits the checking of format strings by 1861 // the compiler and thereby (2) can practically remove the source of 1862 // many format string exploits. 1863 1864 // Format string can be either ObjC string (e.g. @"%d") or 1865 // C string (e.g. "%d") 1866 // ObjC string uses the same format specifiers as C string, so we can use 1867 // the same format string checking logic for both ObjC and C strings. 1868 StringLiteralCheckType CT = 1869 checkFormatStringExpr(OrigFormatExpr, Args, NumArgs, HasVAListArg, 1870 format_idx, firstDataArg, Type, CallType); 1871 if (CT != SLCT_NotALiteral) 1872 // Literal format string found, check done! 1873 return CT == SLCT_CheckedLiteral; 1874 1875 // Strftime is particular as it always uses a single 'time' argument, 1876 // so it is safe to pass a non-literal string. 1877 if (Type == FST_Strftime) 1878 return false; 1879 1880 // Do not emit diag when the string param is a macro expansion and the 1881 // format is either NSString or CFString. This is a hack to prevent 1882 // diag when using the NSLocalizedString and CFCopyLocalizedString macros 1883 // which are usually used in place of NS and CF string literals. 1884 if (Type == FST_NSString && 1885 SourceMgr.isInSystemMacro(Args[format_idx]->getLocStart())) 1886 return false; 1887 1888 // If there are no arguments specified, warn with -Wformat-security, otherwise 1889 // warn only with -Wformat-nonliteral. 1890 if (NumArgs == format_idx+1) 1891 Diag(Args[format_idx]->getLocStart(), 1892 diag::warn_format_nonliteral_noargs) 1893 << OrigFormatExpr->getSourceRange(); 1894 else 1895 Diag(Args[format_idx]->getLocStart(), 1896 diag::warn_format_nonliteral) 1897 << OrigFormatExpr->getSourceRange(); 1898 return false; 1899} 1900 1901namespace { 1902class CheckFormatHandler : public analyze_format_string::FormatStringHandler { 1903protected: 1904 Sema &S; 1905 const StringLiteral *FExpr; 1906 const Expr *OrigFormatExpr; 1907 const unsigned FirstDataArg; 1908 const unsigned NumDataArgs; 1909 const char *Beg; // Start of format string. 1910 const bool HasVAListArg; 1911 const Expr * const *Args; 1912 const unsigned NumArgs; 1913 unsigned FormatIdx; 1914 llvm::BitVector CoveredArgs; 1915 bool usesPositionalArgs; 1916 bool atFirstArg; 1917 bool inFunctionCall; 1918 Sema::VariadicCallType CallType; 1919public: 1920 CheckFormatHandler(Sema &s, const StringLiteral *fexpr, 1921 const Expr *origFormatExpr, unsigned firstDataArg, 1922 unsigned numDataArgs, const char *beg, bool hasVAListArg, 1923 Expr **args, unsigned numArgs, 1924 unsigned formatIdx, bool inFunctionCall, 1925 Sema::VariadicCallType callType) 1926 : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr), 1927 FirstDataArg(firstDataArg), NumDataArgs(numDataArgs), 1928 Beg(beg), HasVAListArg(hasVAListArg), 1929 Args(args), NumArgs(numArgs), FormatIdx(formatIdx), 1930 usesPositionalArgs(false), atFirstArg(true), 1931 inFunctionCall(inFunctionCall), CallType(callType) { 1932 CoveredArgs.resize(numDataArgs); 1933 CoveredArgs.reset(); 1934 } 1935 1936 void DoneProcessing(); 1937 1938 void HandleIncompleteSpecifier(const char *startSpecifier, 1939 unsigned specifierLen); 1940 1941 void HandleInvalidLengthModifier( 1942 const analyze_format_string::FormatSpecifier &FS, 1943 const analyze_format_string::ConversionSpecifier &CS, 1944 const char *startSpecifier, unsigned specifierLen); 1945 1946 void HandleNonStandardLengthModifier( 1947 const analyze_format_string::LengthModifier &LM, 1948 const char *startSpecifier, unsigned specifierLen); 1949 1950 void HandleNonStandardConversionSpecifier( 1951 const analyze_format_string::ConversionSpecifier &CS, 1952 const char *startSpecifier, unsigned specifierLen); 1953 1954 void HandleNonStandardConversionSpecification( 1955 const analyze_format_string::LengthModifier &LM, 1956 const analyze_format_string::ConversionSpecifier &CS, 1957 const char *startSpecifier, unsigned specifierLen); 1958 1959 virtual void HandlePosition(const char *startPos, unsigned posLen); 1960 1961 virtual void HandleInvalidPosition(const char *startSpecifier, 1962 unsigned specifierLen, 1963 analyze_format_string::PositionContext p); 1964 1965 virtual void HandleZeroPosition(const char *startPos, unsigned posLen); 1966 1967 void HandleNullChar(const char *nullCharacter); 1968 1969 template <typename Range> 1970 static void EmitFormatDiagnostic(Sema &S, bool inFunctionCall, 1971 const Expr *ArgumentExpr, 1972 PartialDiagnostic PDiag, 1973 SourceLocation StringLoc, 1974 bool IsStringLocation, Range StringRange, 1975 ArrayRef<FixItHint> Fixit = ArrayRef<FixItHint>()); 1976 1977protected: 1978 bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc, 1979 const char *startSpec, 1980 unsigned specifierLen, 1981 const char *csStart, unsigned csLen); 1982 1983 void HandlePositionalNonpositionalArgs(SourceLocation Loc, 1984 const char *startSpec, 1985 unsigned specifierLen); 1986 1987 SourceRange getFormatStringRange(); 1988 CharSourceRange getSpecifierRange(const char *startSpecifier, 1989 unsigned specifierLen); 1990 SourceLocation getLocationOfByte(const char *x); 1991 1992 const Expr *getDataArg(unsigned i) const; 1993 1994 bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS, 1995 const analyze_format_string::ConversionSpecifier &CS, 1996 const char *startSpecifier, unsigned specifierLen, 1997 unsigned argIndex); 1998 1999 template <typename Range> 2000 void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc, 2001 bool IsStringLocation, Range StringRange, 2002 ArrayRef<FixItHint> Fixit = ArrayRef<FixItHint>()); 2003 2004 void CheckPositionalAndNonpositionalArgs( 2005 const analyze_format_string::FormatSpecifier *FS); 2006}; 2007} 2008 2009SourceRange CheckFormatHandler::getFormatStringRange() { 2010 return OrigFormatExpr->getSourceRange(); 2011} 2012 2013CharSourceRange CheckFormatHandler:: 2014getSpecifierRange(const char *startSpecifier, unsigned specifierLen) { 2015 SourceLocation Start = getLocationOfByte(startSpecifier); 2016 SourceLocation End = getLocationOfByte(startSpecifier + specifierLen - 1); 2017 2018 // Advance the end SourceLocation by one due to half-open ranges. 2019 End = End.getLocWithOffset(1); 2020 2021 return CharSourceRange::getCharRange(Start, End); 2022} 2023 2024SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) { 2025 return S.getLocationOfStringLiteralByte(FExpr, x - Beg); 2026} 2027 2028void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier, 2029 unsigned specifierLen){ 2030 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier), 2031 getLocationOfByte(startSpecifier), 2032 /*IsStringLocation*/true, 2033 getSpecifierRange(startSpecifier, specifierLen)); 2034} 2035 2036void CheckFormatHandler::HandleInvalidLengthModifier( 2037 const analyze_format_string::FormatSpecifier &FS, 2038 const analyze_format_string::ConversionSpecifier &CS, 2039 const char *startSpecifier, unsigned specifierLen) { 2040 using namespace analyze_format_string; 2041 2042 const LengthModifier &LM = FS.getLengthModifier(); 2043 CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength()); 2044 2045 // See if we know how to fix this length modifier. 2046 llvm::Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier(); 2047 if (FixedLM) { 2048 EmitFormatDiagnostic(S.PDiag(diag::warn_format_nonsensical_length) 2049 << LM.toString() << CS.toString(), 2050 getLocationOfByte(LM.getStart()), 2051 /*IsStringLocation*/true, 2052 getSpecifierRange(startSpecifier, specifierLen)); 2053 2054 S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier) 2055 << FixedLM->toString() 2056 << FixItHint::CreateReplacement(LMRange, FixedLM->toString()); 2057 2058 } else { 2059 EmitFormatDiagnostic(S.PDiag(diag::warn_format_nonsensical_length) 2060 << LM.toString() << CS.toString(), 2061 getLocationOfByte(LM.getStart()), 2062 /*IsStringLocation*/true, 2063 getSpecifierRange(startSpecifier, specifierLen), 2064 FixItHint::CreateRemoval(LMRange)); 2065 } 2066} 2067 2068void CheckFormatHandler::HandleNonStandardLengthModifier( 2069 const analyze_format_string::LengthModifier &LM, 2070 const char *startSpecifier, unsigned specifierLen) { 2071 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) << LM.toString() 2072 << 0, 2073 getLocationOfByte(LM.getStart()), 2074 /*IsStringLocation*/true, 2075 getSpecifierRange(startSpecifier, specifierLen)); 2076} 2077 2078void CheckFormatHandler::HandleNonStandardConversionSpecifier( 2079 const analyze_format_string::ConversionSpecifier &CS, 2080 const char *startSpecifier, unsigned specifierLen) { 2081 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) << CS.toString() 2082 << 1, 2083 getLocationOfByte(CS.getStart()), 2084 /*IsStringLocation*/true, 2085 getSpecifierRange(startSpecifier, specifierLen)); 2086} 2087 2088void CheckFormatHandler::HandleNonStandardConversionSpecification( 2089 const analyze_format_string::LengthModifier &LM, 2090 const analyze_format_string::ConversionSpecifier &CS, 2091 const char *startSpecifier, unsigned specifierLen) { 2092 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_conversion_spec) 2093 << LM.toString() << CS.toString(), 2094 getLocationOfByte(LM.getStart()), 2095 /*IsStringLocation*/true, 2096 getSpecifierRange(startSpecifier, specifierLen)); 2097} 2098 2099void CheckFormatHandler::HandlePosition(const char *startPos, 2100 unsigned posLen) { 2101 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg), 2102 getLocationOfByte(startPos), 2103 /*IsStringLocation*/true, 2104 getSpecifierRange(startPos, posLen)); 2105} 2106 2107void 2108CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen, 2109 analyze_format_string::PositionContext p) { 2110 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier) 2111 << (unsigned) p, 2112 getLocationOfByte(startPos), /*IsStringLocation*/true, 2113 getSpecifierRange(startPos, posLen)); 2114} 2115 2116void CheckFormatHandler::HandleZeroPosition(const char *startPos, 2117 unsigned posLen) { 2118 EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier), 2119 getLocationOfByte(startPos), 2120 /*IsStringLocation*/true, 2121 getSpecifierRange(startPos, posLen)); 2122} 2123 2124void CheckFormatHandler::HandleNullChar(const char *nullCharacter) { 2125 if (!isa<ObjCStringLiteral>(OrigFormatExpr)) { 2126 // The presence of a null character is likely an error. 2127 EmitFormatDiagnostic( 2128 S.PDiag(diag::warn_printf_format_string_contains_null_char), 2129 getLocationOfByte(nullCharacter), /*IsStringLocation*/true, 2130 getFormatStringRange()); 2131 } 2132} 2133 2134// Note that this may return NULL if there was an error parsing or building 2135// one of the argument expressions. 2136const Expr *CheckFormatHandler::getDataArg(unsigned i) const { 2137 return Args[FirstDataArg + i]; 2138} 2139 2140void CheckFormatHandler::DoneProcessing() { 2141 // Does the number of data arguments exceed the number of 2142 // format conversions in the format string? 2143 if (!HasVAListArg) { 2144 // Find any arguments that weren't covered. 2145 CoveredArgs.flip(); 2146 signed notCoveredArg = CoveredArgs.find_first(); 2147 if (notCoveredArg >= 0) { 2148 assert((unsigned)notCoveredArg < NumDataArgs); 2149 if (const Expr *E = getDataArg((unsigned) notCoveredArg)) { 2150 SourceLocation Loc = E->getLocStart(); 2151 if (!S.getSourceManager().isInSystemMacro(Loc)) { 2152 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_data_arg_not_used), 2153 Loc, /*IsStringLocation*/false, 2154 getFormatStringRange()); 2155 } 2156 } 2157 } 2158 } 2159} 2160 2161bool 2162CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex, 2163 SourceLocation Loc, 2164 const char *startSpec, 2165 unsigned specifierLen, 2166 const char *csStart, 2167 unsigned csLen) { 2168 2169 bool keepGoing = true; 2170 if (argIndex < NumDataArgs) { 2171 // Consider the argument coverered, even though the specifier doesn't 2172 // make sense. 2173 CoveredArgs.set(argIndex); 2174 } 2175 else { 2176 // If argIndex exceeds the number of data arguments we 2177 // don't issue a warning because that is just a cascade of warnings (and 2178 // they may have intended '%%' anyway). We don't want to continue processing 2179 // the format string after this point, however, as we will like just get 2180 // gibberish when trying to match arguments. 2181 keepGoing = false; 2182 } 2183 2184 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion) 2185 << StringRef(csStart, csLen), 2186 Loc, /*IsStringLocation*/true, 2187 getSpecifierRange(startSpec, specifierLen)); 2188 2189 return keepGoing; 2190} 2191 2192void 2193CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc, 2194 const char *startSpec, 2195 unsigned specifierLen) { 2196 EmitFormatDiagnostic( 2197 S.PDiag(diag::warn_format_mix_positional_nonpositional_args), 2198 Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen)); 2199} 2200 2201bool 2202CheckFormatHandler::CheckNumArgs( 2203 const analyze_format_string::FormatSpecifier &FS, 2204 const analyze_format_string::ConversionSpecifier &CS, 2205 const char *startSpecifier, unsigned specifierLen, unsigned argIndex) { 2206 2207 if (argIndex >= NumDataArgs) { 2208 PartialDiagnostic PDiag = FS.usesPositionalArg() 2209 ? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args) 2210 << (argIndex+1) << NumDataArgs) 2211 : S.PDiag(diag::warn_printf_insufficient_data_args); 2212 EmitFormatDiagnostic( 2213 PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true, 2214 getSpecifierRange(startSpecifier, specifierLen)); 2215 return false; 2216 } 2217 return true; 2218} 2219 2220template<typename Range> 2221void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag, 2222 SourceLocation Loc, 2223 bool IsStringLocation, 2224 Range StringRange, 2225 ArrayRef<FixItHint> FixIt) { 2226 EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag, 2227 Loc, IsStringLocation, StringRange, FixIt); 2228} 2229 2230/// \brief If the format string is not within the funcion call, emit a note 2231/// so that the function call and string are in diagnostic messages. 2232/// 2233/// \param InFunctionCall if true, the format string is within the function 2234/// call and only one diagnostic message will be produced. Otherwise, an 2235/// extra note will be emitted pointing to location of the format string. 2236/// 2237/// \param ArgumentExpr the expression that is passed as the format string 2238/// argument in the function call. Used for getting locations when two 2239/// diagnostics are emitted. 2240/// 2241/// \param PDiag the callee should already have provided any strings for the 2242/// diagnostic message. This function only adds locations and fixits 2243/// to diagnostics. 2244/// 2245/// \param Loc primary location for diagnostic. If two diagnostics are 2246/// required, one will be at Loc and a new SourceLocation will be created for 2247/// the other one. 2248/// 2249/// \param IsStringLocation if true, Loc points to the format string should be 2250/// used for the note. Otherwise, Loc points to the argument list and will 2251/// be used with PDiag. 2252/// 2253/// \param StringRange some or all of the string to highlight. This is 2254/// templated so it can accept either a CharSourceRange or a SourceRange. 2255/// 2256/// \param FixIt optional fix it hint for the format string. 2257template<typename Range> 2258void CheckFormatHandler::EmitFormatDiagnostic(Sema &S, bool InFunctionCall, 2259 const Expr *ArgumentExpr, 2260 PartialDiagnostic PDiag, 2261 SourceLocation Loc, 2262 bool IsStringLocation, 2263 Range StringRange, 2264 ArrayRef<FixItHint> FixIt) { 2265 if (InFunctionCall) { 2266 const Sema::SemaDiagnosticBuilder &D = S.Diag(Loc, PDiag); 2267 D << StringRange; 2268 for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end(); 2269 I != E; ++I) { 2270 D << *I; 2271 } 2272 } else { 2273 S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag) 2274 << ArgumentExpr->getSourceRange(); 2275 2276 const Sema::SemaDiagnosticBuilder &Note = 2277 S.Diag(IsStringLocation ? Loc : StringRange.getBegin(), 2278 diag::note_format_string_defined); 2279 2280 Note << StringRange; 2281 for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end(); 2282 I != E; ++I) { 2283 Note << *I; 2284 } 2285 } 2286} 2287 2288//===--- CHECK: Printf format string checking ------------------------------===// 2289 2290namespace { 2291class CheckPrintfHandler : public CheckFormatHandler { 2292 bool ObjCContext; 2293public: 2294 CheckPrintfHandler(Sema &s, const StringLiteral *fexpr, 2295 const Expr *origFormatExpr, unsigned firstDataArg, 2296 unsigned numDataArgs, bool isObjC, 2297 const char *beg, bool hasVAListArg, 2298 Expr **Args, unsigned NumArgs, 2299 unsigned formatIdx, bool inFunctionCall, 2300 Sema::VariadicCallType CallType) 2301 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 2302 numDataArgs, beg, hasVAListArg, Args, NumArgs, 2303 formatIdx, inFunctionCall, CallType), ObjCContext(isObjC) 2304 {} 2305 2306 2307 bool HandleInvalidPrintfConversionSpecifier( 2308 const analyze_printf::PrintfSpecifier &FS, 2309 const char *startSpecifier, 2310 unsigned specifierLen); 2311 2312 bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS, 2313 const char *startSpecifier, 2314 unsigned specifierLen); 2315 bool checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 2316 const char *StartSpecifier, 2317 unsigned SpecifierLen, 2318 const Expr *E); 2319 2320 bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k, 2321 const char *startSpecifier, unsigned specifierLen); 2322 void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS, 2323 const analyze_printf::OptionalAmount &Amt, 2324 unsigned type, 2325 const char *startSpecifier, unsigned specifierLen); 2326 void HandleFlag(const analyze_printf::PrintfSpecifier &FS, 2327 const analyze_printf::OptionalFlag &flag, 2328 const char *startSpecifier, unsigned specifierLen); 2329 void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS, 2330 const analyze_printf::OptionalFlag &ignoredFlag, 2331 const analyze_printf::OptionalFlag &flag, 2332 const char *startSpecifier, unsigned specifierLen); 2333 bool checkForCStrMembers(const analyze_printf::ArgType &AT, 2334 const Expr *E, const CharSourceRange &CSR); 2335 2336}; 2337} 2338 2339bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier( 2340 const analyze_printf::PrintfSpecifier &FS, 2341 const char *startSpecifier, 2342 unsigned specifierLen) { 2343 const analyze_printf::PrintfConversionSpecifier &CS = 2344 FS.getConversionSpecifier(); 2345 2346 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 2347 getLocationOfByte(CS.getStart()), 2348 startSpecifier, specifierLen, 2349 CS.getStart(), CS.getLength()); 2350} 2351 2352bool CheckPrintfHandler::HandleAmount( 2353 const analyze_format_string::OptionalAmount &Amt, 2354 unsigned k, const char *startSpecifier, 2355 unsigned specifierLen) { 2356 2357 if (Amt.hasDataArgument()) { 2358 if (!HasVAListArg) { 2359 unsigned argIndex = Amt.getArgIndex(); 2360 if (argIndex >= NumDataArgs) { 2361 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg) 2362 << k, 2363 getLocationOfByte(Amt.getStart()), 2364 /*IsStringLocation*/true, 2365 getSpecifierRange(startSpecifier, specifierLen)); 2366 // Don't do any more checking. We will just emit 2367 // spurious errors. 2368 return false; 2369 } 2370 2371 // Type check the data argument. It should be an 'int'. 2372 // Although not in conformance with C99, we also allow the argument to be 2373 // an 'unsigned int' as that is a reasonably safe case. GCC also 2374 // doesn't emit a warning for that case. 2375 CoveredArgs.set(argIndex); 2376 const Expr *Arg = getDataArg(argIndex); 2377 if (!Arg) 2378 return false; 2379 2380 QualType T = Arg->getType(); 2381 2382 const analyze_printf::ArgType &AT = Amt.getArgType(S.Context); 2383 assert(AT.isValid()); 2384 2385 if (!AT.matchesType(S.Context, T)) { 2386 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type) 2387 << k << AT.getRepresentativeTypeName(S.Context) 2388 << T << Arg->getSourceRange(), 2389 getLocationOfByte(Amt.getStart()), 2390 /*IsStringLocation*/true, 2391 getSpecifierRange(startSpecifier, specifierLen)); 2392 // Don't do any more checking. We will just emit 2393 // spurious errors. 2394 return false; 2395 } 2396 } 2397 } 2398 return true; 2399} 2400 2401void CheckPrintfHandler::HandleInvalidAmount( 2402 const analyze_printf::PrintfSpecifier &FS, 2403 const analyze_printf::OptionalAmount &Amt, 2404 unsigned type, 2405 const char *startSpecifier, 2406 unsigned specifierLen) { 2407 const analyze_printf::PrintfConversionSpecifier &CS = 2408 FS.getConversionSpecifier(); 2409 2410 FixItHint fixit = 2411 Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant 2412 ? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(), 2413 Amt.getConstantLength())) 2414 : FixItHint(); 2415 2416 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount) 2417 << type << CS.toString(), 2418 getLocationOfByte(Amt.getStart()), 2419 /*IsStringLocation*/true, 2420 getSpecifierRange(startSpecifier, specifierLen), 2421 fixit); 2422} 2423 2424void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS, 2425 const analyze_printf::OptionalFlag &flag, 2426 const char *startSpecifier, 2427 unsigned specifierLen) { 2428 // Warn about pointless flag with a fixit removal. 2429 const analyze_printf::PrintfConversionSpecifier &CS = 2430 FS.getConversionSpecifier(); 2431 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag) 2432 << flag.toString() << CS.toString(), 2433 getLocationOfByte(flag.getPosition()), 2434 /*IsStringLocation*/true, 2435 getSpecifierRange(startSpecifier, specifierLen), 2436 FixItHint::CreateRemoval( 2437 getSpecifierRange(flag.getPosition(), 1))); 2438} 2439 2440void CheckPrintfHandler::HandleIgnoredFlag( 2441 const analyze_printf::PrintfSpecifier &FS, 2442 const analyze_printf::OptionalFlag &ignoredFlag, 2443 const analyze_printf::OptionalFlag &flag, 2444 const char *startSpecifier, 2445 unsigned specifierLen) { 2446 // Warn about ignored flag with a fixit removal. 2447 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag) 2448 << ignoredFlag.toString() << flag.toString(), 2449 getLocationOfByte(ignoredFlag.getPosition()), 2450 /*IsStringLocation*/true, 2451 getSpecifierRange(startSpecifier, specifierLen), 2452 FixItHint::CreateRemoval( 2453 getSpecifierRange(ignoredFlag.getPosition(), 1))); 2454} 2455 2456// Determines if the specified is a C++ class or struct containing 2457// a member with the specified name and kind (e.g. a CXXMethodDecl named 2458// "c_str()"). 2459template<typename MemberKind> 2460static llvm::SmallPtrSet<MemberKind*, 1> 2461CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) { 2462 const RecordType *RT = Ty->getAs<RecordType>(); 2463 llvm::SmallPtrSet<MemberKind*, 1> Results; 2464 2465 if (!RT) 2466 return Results; 2467 const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()); 2468 if (!RD) 2469 return Results; 2470 2471 LookupResult R(S, &S.PP.getIdentifierTable().get(Name), SourceLocation(), 2472 Sema::LookupMemberName); 2473 2474 // We just need to include all members of the right kind turned up by the 2475 // filter, at this point. 2476 if (S.LookupQualifiedName(R, RT->getDecl())) 2477 for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) { 2478 NamedDecl *decl = (*I)->getUnderlyingDecl(); 2479 if (MemberKind *FK = dyn_cast<MemberKind>(decl)) 2480 Results.insert(FK); 2481 } 2482 return Results; 2483} 2484 2485// Check if a (w)string was passed when a (w)char* was needed, and offer a 2486// better diagnostic if so. AT is assumed to be valid. 2487// Returns true when a c_str() conversion method is found. 2488bool CheckPrintfHandler::checkForCStrMembers( 2489 const analyze_printf::ArgType &AT, const Expr *E, 2490 const CharSourceRange &CSR) { 2491 typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet; 2492 2493 MethodSet Results = 2494 CXXRecordMembersNamed<CXXMethodDecl>("c_str", S, E->getType()); 2495 2496 for (MethodSet::iterator MI = Results.begin(), ME = Results.end(); 2497 MI != ME; ++MI) { 2498 const CXXMethodDecl *Method = *MI; 2499 if (Method->getNumParams() == 0 && 2500 AT.matchesType(S.Context, Method->getResultType())) { 2501 // FIXME: Suggest parens if the expression needs them. 2502 SourceLocation EndLoc = 2503 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()); 2504 S.Diag(E->getLocStart(), diag::note_printf_c_str) 2505 << "c_str()" 2506 << FixItHint::CreateInsertion(EndLoc, ".c_str()"); 2507 return true; 2508 } 2509 } 2510 2511 return false; 2512} 2513 2514bool 2515CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier 2516 &FS, 2517 const char *startSpecifier, 2518 unsigned specifierLen) { 2519 2520 using namespace analyze_format_string; 2521 using namespace analyze_printf; 2522 const PrintfConversionSpecifier &CS = FS.getConversionSpecifier(); 2523 2524 if (FS.consumesDataArgument()) { 2525 if (atFirstArg) { 2526 atFirstArg = false; 2527 usesPositionalArgs = FS.usesPositionalArg(); 2528 } 2529 else if (usesPositionalArgs != FS.usesPositionalArg()) { 2530 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 2531 startSpecifier, specifierLen); 2532 return false; 2533 } 2534 } 2535 2536 // First check if the field width, precision, and conversion specifier 2537 // have matching data arguments. 2538 if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0, 2539 startSpecifier, specifierLen)) { 2540 return false; 2541 } 2542 2543 if (!HandleAmount(FS.getPrecision(), /* precision */ 1, 2544 startSpecifier, specifierLen)) { 2545 return false; 2546 } 2547 2548 if (!CS.consumesDataArgument()) { 2549 // FIXME: Technically specifying a precision or field width here 2550 // makes no sense. Worth issuing a warning at some point. 2551 return true; 2552 } 2553 2554 // Consume the argument. 2555 unsigned argIndex = FS.getArgIndex(); 2556 if (argIndex < NumDataArgs) { 2557 // The check to see if the argIndex is valid will come later. 2558 // We set the bit here because we may exit early from this 2559 // function if we encounter some other error. 2560 CoveredArgs.set(argIndex); 2561 } 2562 2563 // Check for using an Objective-C specific conversion specifier 2564 // in a non-ObjC literal. 2565 if (!ObjCContext && CS.isObjCArg()) { 2566 return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier, 2567 specifierLen); 2568 } 2569 2570 // Check for invalid use of field width 2571 if (!FS.hasValidFieldWidth()) { 2572 HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0, 2573 startSpecifier, specifierLen); 2574 } 2575 2576 // Check for invalid use of precision 2577 if (!FS.hasValidPrecision()) { 2578 HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1, 2579 startSpecifier, specifierLen); 2580 } 2581 2582 // Check each flag does not conflict with any other component. 2583 if (!FS.hasValidThousandsGroupingPrefix()) 2584 HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen); 2585 if (!FS.hasValidLeadingZeros()) 2586 HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen); 2587 if (!FS.hasValidPlusPrefix()) 2588 HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen); 2589 if (!FS.hasValidSpacePrefix()) 2590 HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen); 2591 if (!FS.hasValidAlternativeForm()) 2592 HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen); 2593 if (!FS.hasValidLeftJustified()) 2594 HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen); 2595 2596 // Check that flags are not ignored by another flag 2597 if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+' 2598 HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(), 2599 startSpecifier, specifierLen); 2600 if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-' 2601 HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(), 2602 startSpecifier, specifierLen); 2603 2604 // Check the length modifier is valid with the given conversion specifier. 2605 const LengthModifier &LM = FS.getLengthModifier(); 2606 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 2607 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen); 2608 else if (!FS.hasStandardLengthModifier()) 2609 HandleNonStandardLengthModifier(LM, startSpecifier, specifierLen); 2610 else if (!FS.hasStandardLengthConversionCombination()) 2611 HandleNonStandardConversionSpecification(LM, CS, startSpecifier, 2612 specifierLen); 2613 2614 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 2615 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 2616 2617 // The remaining checks depend on the data arguments. 2618 if (HasVAListArg) 2619 return true; 2620 2621 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 2622 return false; 2623 2624 const Expr *Arg = getDataArg(argIndex); 2625 if (!Arg) 2626 return true; 2627 2628 return checkFormatExpr(FS, startSpecifier, specifierLen, Arg); 2629} 2630 2631static bool requiresParensToAddCast(const Expr *E) { 2632 // FIXME: We should have a general way to reason about operator 2633 // precedence and whether parens are actually needed here. 2634 // Take care of a few common cases where they aren't. 2635 const Expr *Inside = E->IgnoreImpCasts(); 2636 if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Inside)) 2637 Inside = POE->getSyntacticForm()->IgnoreImpCasts(); 2638 2639 switch (Inside->getStmtClass()) { 2640 case Stmt::ArraySubscriptExprClass: 2641 case Stmt::CallExprClass: 2642 case Stmt::DeclRefExprClass: 2643 case Stmt::MemberExprClass: 2644 case Stmt::ObjCIvarRefExprClass: 2645 case Stmt::ObjCMessageExprClass: 2646 case Stmt::ObjCPropertyRefExprClass: 2647 case Stmt::ParenExprClass: 2648 case Stmt::UnaryOperatorClass: 2649 return false; 2650 default: 2651 return true; 2652 } 2653} 2654 2655bool 2656CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 2657 const char *StartSpecifier, 2658 unsigned SpecifierLen, 2659 const Expr *E) { 2660 using namespace analyze_format_string; 2661 using namespace analyze_printf; 2662 // Now type check the data expression that matches the 2663 // format specifier. 2664 const analyze_printf::ArgType &AT = FS.getArgType(S.Context, 2665 ObjCContext); 2666 if (!AT.isValid()) 2667 return true; 2668 2669 QualType IntendedTy = E->getType(); 2670 if (AT.matchesType(S.Context, IntendedTy)) 2671 return true; 2672 2673 // Look through argument promotions for our error message's reported type. 2674 // This includes the integral and floating promotions, but excludes array 2675 // and function pointer decay; seeing that an argument intended to be a 2676 // string has type 'char [6]' is probably more confusing than 'char *'. 2677 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 2678 if (ICE->getCastKind() == CK_IntegralCast || 2679 ICE->getCastKind() == CK_FloatingCast) { 2680 E = ICE->getSubExpr(); 2681 IntendedTy = E->getType(); 2682 2683 // Check if we didn't match because of an implicit cast from a 'char' 2684 // or 'short' to an 'int'. This is done because printf is a varargs 2685 // function. 2686 if (ICE->getType() == S.Context.IntTy || 2687 ICE->getType() == S.Context.UnsignedIntTy) { 2688 // All further checking is done on the subexpression. 2689 if (AT.matchesType(S.Context, IntendedTy)) 2690 return true; 2691 } 2692 } 2693 } 2694 2695 if (S.Context.getTargetInfo().getTriple().isOSDarwin()) { 2696 // Special-case some of Darwin's platform-independence types. 2697 if (const TypedefType *UserTy = IntendedTy->getAs<TypedefType>()) { 2698 StringRef Name = UserTy->getDecl()->getName(); 2699 IntendedTy = llvm::StringSwitch<QualType>(Name) 2700 .Case("NSInteger", S.Context.LongTy) 2701 .Case("NSUInteger", S.Context.UnsignedLongTy) 2702 .Case("SInt32", S.Context.IntTy) 2703 .Case("UInt32", S.Context.UnsignedIntTy) 2704 .Default(IntendedTy); 2705 } 2706 } 2707 2708 // We may be able to offer a FixItHint if it is a supported type. 2709 PrintfSpecifier fixedFS = FS; 2710 bool success = fixedFS.fixType(IntendedTy, S.getLangOpts(), 2711 S.Context, ObjCContext); 2712 2713 if (success) { 2714 // Get the fix string from the fixed format specifier 2715 SmallString<16> buf; 2716 llvm::raw_svector_ostream os(buf); 2717 fixedFS.toString(os); 2718 2719 CharSourceRange SpecRange = getSpecifierRange(StartSpecifier, SpecifierLen); 2720 2721 if (IntendedTy != E->getType()) { 2722 // The canonical type for formatting this value is different from the 2723 // actual type of the expression. (This occurs, for example, with Darwin's 2724 // NSInteger on 32-bit platforms, where it is typedef'd as 'int', but 2725 // should be printed as 'long' for 64-bit compatibility.) 2726 // Rather than emitting a normal format/argument mismatch, we want to 2727 // add a cast to the recommended type (and correct the format string 2728 // if necessary). 2729 SmallString<16> CastBuf; 2730 llvm::raw_svector_ostream CastFix(CastBuf); 2731 CastFix << "("; 2732 IntendedTy.print(CastFix, S.Context.getPrintingPolicy()); 2733 CastFix << ")"; 2734 2735 SmallVector<FixItHint,4> Hints; 2736 if (!AT.matchesType(S.Context, IntendedTy)) 2737 Hints.push_back(FixItHint::CreateReplacement(SpecRange, os.str())); 2738 2739 if (const CStyleCastExpr *CCast = dyn_cast<CStyleCastExpr>(E)) { 2740 // If there's already a cast present, just replace it. 2741 SourceRange CastRange(CCast->getLParenLoc(), CCast->getRParenLoc()); 2742 Hints.push_back(FixItHint::CreateReplacement(CastRange, CastFix.str())); 2743 2744 } else if (!requiresParensToAddCast(E)) { 2745 // If the expression has high enough precedence, 2746 // just write the C-style cast. 2747 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 2748 CastFix.str())); 2749 } else { 2750 // Otherwise, add parens around the expression as well as the cast. 2751 CastFix << "("; 2752 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 2753 CastFix.str())); 2754 2755 SourceLocation After = S.PP.getLocForEndOfToken(E->getLocEnd()); 2756 Hints.push_back(FixItHint::CreateInsertion(After, ")")); 2757 } 2758 2759 // We extract the name from the typedef because we don't want to show 2760 // the underlying type in the diagnostic. 2761 const TypedefType *UserTy = cast<TypedefType>(E->getType()); 2762 StringRef Name = UserTy->getDecl()->getName(); 2763 2764 // Finally, emit the diagnostic. 2765 EmitFormatDiagnostic(S.PDiag(diag::warn_format_argument_needs_cast) 2766 << Name << IntendedTy 2767 << E->getSourceRange(), 2768 E->getLocStart(), /*IsStringLocation=*/false, 2769 SpecRange, Hints); 2770 } else { 2771 EmitFormatDiagnostic( 2772 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2773 << AT.getRepresentativeTypeName(S.Context) << IntendedTy 2774 << E->getSourceRange(), 2775 E->getLocStart(), 2776 /*IsStringLocation*/false, 2777 SpecRange, 2778 FixItHint::CreateReplacement(SpecRange, os.str())); 2779 } 2780 } else { 2781 const CharSourceRange &CSR = getSpecifierRange(StartSpecifier, 2782 SpecifierLen); 2783 // Since the warning for passing non-POD types to variadic functions 2784 // was deferred until now, we emit a warning for non-POD 2785 // arguments here. 2786 if (S.isValidVarArgType(E->getType()) == Sema::VAK_Invalid) { 2787 unsigned DiagKind; 2788 if (E->getType()->isObjCObjectType()) 2789 DiagKind = diag::err_cannot_pass_objc_interface_to_vararg_format; 2790 else 2791 DiagKind = diag::warn_non_pod_vararg_with_format_string; 2792 2793 EmitFormatDiagnostic( 2794 S.PDiag(DiagKind) 2795 << S.getLangOpts().CPlusPlus0x 2796 << E->getType() 2797 << CallType 2798 << AT.getRepresentativeTypeName(S.Context) 2799 << CSR 2800 << E->getSourceRange(), 2801 E->getLocStart(), /*IsStringLocation*/false, CSR); 2802 2803 checkForCStrMembers(AT, E, CSR); 2804 } else 2805 EmitFormatDiagnostic( 2806 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2807 << AT.getRepresentativeTypeName(S.Context) << E->getType() 2808 << CSR 2809 << E->getSourceRange(), 2810 E->getLocStart(), /*IsStringLocation*/false, CSR); 2811 } 2812 2813 return true; 2814} 2815 2816//===--- CHECK: Scanf format string checking ------------------------------===// 2817 2818namespace { 2819class CheckScanfHandler : public CheckFormatHandler { 2820public: 2821 CheckScanfHandler(Sema &s, const StringLiteral *fexpr, 2822 const Expr *origFormatExpr, unsigned firstDataArg, 2823 unsigned numDataArgs, const char *beg, bool hasVAListArg, 2824 Expr **Args, unsigned NumArgs, 2825 unsigned formatIdx, bool inFunctionCall, 2826 Sema::VariadicCallType CallType) 2827 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 2828 numDataArgs, beg, hasVAListArg, 2829 Args, NumArgs, formatIdx, inFunctionCall, CallType) 2830 {} 2831 2832 bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS, 2833 const char *startSpecifier, 2834 unsigned specifierLen); 2835 2836 bool HandleInvalidScanfConversionSpecifier( 2837 const analyze_scanf::ScanfSpecifier &FS, 2838 const char *startSpecifier, 2839 unsigned specifierLen); 2840 2841 void HandleIncompleteScanList(const char *start, const char *end); 2842}; 2843} 2844 2845void CheckScanfHandler::HandleIncompleteScanList(const char *start, 2846 const char *end) { 2847 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete), 2848 getLocationOfByte(end), /*IsStringLocation*/true, 2849 getSpecifierRange(start, end - start)); 2850} 2851 2852bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier( 2853 const analyze_scanf::ScanfSpecifier &FS, 2854 const char *startSpecifier, 2855 unsigned specifierLen) { 2856 2857 const analyze_scanf::ScanfConversionSpecifier &CS = 2858 FS.getConversionSpecifier(); 2859 2860 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 2861 getLocationOfByte(CS.getStart()), 2862 startSpecifier, specifierLen, 2863 CS.getStart(), CS.getLength()); 2864} 2865 2866bool CheckScanfHandler::HandleScanfSpecifier( 2867 const analyze_scanf::ScanfSpecifier &FS, 2868 const char *startSpecifier, 2869 unsigned specifierLen) { 2870 2871 using namespace analyze_scanf; 2872 using namespace analyze_format_string; 2873 2874 const ScanfConversionSpecifier &CS = FS.getConversionSpecifier(); 2875 2876 // Handle case where '%' and '*' don't consume an argument. These shouldn't 2877 // be used to decide if we are using positional arguments consistently. 2878 if (FS.consumesDataArgument()) { 2879 if (atFirstArg) { 2880 atFirstArg = false; 2881 usesPositionalArgs = FS.usesPositionalArg(); 2882 } 2883 else if (usesPositionalArgs != FS.usesPositionalArg()) { 2884 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 2885 startSpecifier, specifierLen); 2886 return false; 2887 } 2888 } 2889 2890 // Check if the field with is non-zero. 2891 const OptionalAmount &Amt = FS.getFieldWidth(); 2892 if (Amt.getHowSpecified() == OptionalAmount::Constant) { 2893 if (Amt.getConstantAmount() == 0) { 2894 const CharSourceRange &R = getSpecifierRange(Amt.getStart(), 2895 Amt.getConstantLength()); 2896 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width), 2897 getLocationOfByte(Amt.getStart()), 2898 /*IsStringLocation*/true, R, 2899 FixItHint::CreateRemoval(R)); 2900 } 2901 } 2902 2903 if (!FS.consumesDataArgument()) { 2904 // FIXME: Technically specifying a precision or field width here 2905 // makes no sense. Worth issuing a warning at some point. 2906 return true; 2907 } 2908 2909 // Consume the argument. 2910 unsigned argIndex = FS.getArgIndex(); 2911 if (argIndex < NumDataArgs) { 2912 // The check to see if the argIndex is valid will come later. 2913 // We set the bit here because we may exit early from this 2914 // function if we encounter some other error. 2915 CoveredArgs.set(argIndex); 2916 } 2917 2918 // Check the length modifier is valid with the given conversion specifier. 2919 const LengthModifier &LM = FS.getLengthModifier(); 2920 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 2921 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen); 2922 else if (!FS.hasStandardLengthModifier()) 2923 HandleNonStandardLengthModifier(LM, startSpecifier, specifierLen); 2924 else if (!FS.hasStandardLengthConversionCombination()) 2925 HandleNonStandardConversionSpecification(LM, CS, startSpecifier, 2926 specifierLen); 2927 2928 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 2929 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 2930 2931 // The remaining checks depend on the data arguments. 2932 if (HasVAListArg) 2933 return true; 2934 2935 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 2936 return false; 2937 2938 // Check that the argument type matches the format specifier. 2939 const Expr *Ex = getDataArg(argIndex); 2940 if (!Ex) 2941 return true; 2942 2943 const analyze_format_string::ArgType &AT = FS.getArgType(S.Context); 2944 if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType())) { 2945 ScanfSpecifier fixedFS = FS; 2946 bool success = fixedFS.fixType(Ex->getType(), S.getLangOpts(), 2947 S.Context); 2948 2949 if (success) { 2950 // Get the fix string from the fixed format specifier. 2951 SmallString<128> buf; 2952 llvm::raw_svector_ostream os(buf); 2953 fixedFS.toString(os); 2954 2955 EmitFormatDiagnostic( 2956 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2957 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() 2958 << Ex->getSourceRange(), 2959 Ex->getLocStart(), 2960 /*IsStringLocation*/false, 2961 getSpecifierRange(startSpecifier, specifierLen), 2962 FixItHint::CreateReplacement( 2963 getSpecifierRange(startSpecifier, specifierLen), 2964 os.str())); 2965 } else { 2966 EmitFormatDiagnostic( 2967 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2968 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() 2969 << Ex->getSourceRange(), 2970 Ex->getLocStart(), 2971 /*IsStringLocation*/false, 2972 getSpecifierRange(startSpecifier, specifierLen)); 2973 } 2974 } 2975 2976 return true; 2977} 2978 2979void Sema::CheckFormatString(const StringLiteral *FExpr, 2980 const Expr *OrigFormatExpr, 2981 Expr **Args, unsigned NumArgs, 2982 bool HasVAListArg, unsigned format_idx, 2983 unsigned firstDataArg, FormatStringType Type, 2984 bool inFunctionCall, VariadicCallType CallType) { 2985 2986 // CHECK: is the format string a wide literal? 2987 if (!FExpr->isAscii() && !FExpr->isUTF8()) { 2988 CheckFormatHandler::EmitFormatDiagnostic( 2989 *this, inFunctionCall, Args[format_idx], 2990 PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(), 2991 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 2992 return; 2993 } 2994 2995 // Str - The format string. NOTE: this is NOT null-terminated! 2996 StringRef StrRef = FExpr->getString(); 2997 const char *Str = StrRef.data(); 2998 unsigned StrLen = StrRef.size(); 2999 const unsigned numDataArgs = NumArgs - firstDataArg; 3000 3001 // CHECK: empty format string? 3002 if (StrLen == 0 && numDataArgs > 0) { 3003 CheckFormatHandler::EmitFormatDiagnostic( 3004 *this, inFunctionCall, Args[format_idx], 3005 PDiag(diag::warn_empty_format_string), FExpr->getLocStart(), 3006 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 3007 return; 3008 } 3009 3010 if (Type == FST_Printf || Type == FST_NSString) { 3011 CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 3012 numDataArgs, (Type == FST_NSString), 3013 Str, HasVAListArg, Args, NumArgs, format_idx, 3014 inFunctionCall, CallType); 3015 3016 if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen, 3017 getLangOpts())) 3018 H.DoneProcessing(); 3019 } else if (Type == FST_Scanf) { 3020 CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, numDataArgs, 3021 Str, HasVAListArg, Args, NumArgs, format_idx, 3022 inFunctionCall, CallType); 3023 3024 if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen, 3025 getLangOpts())) 3026 H.DoneProcessing(); 3027 } // TODO: handle other formats 3028} 3029 3030//===--- CHECK: Standard memory functions ---------------------------------===// 3031 3032/// \brief Determine whether the given type is a dynamic class type (e.g., 3033/// whether it has a vtable). 3034static bool isDynamicClassType(QualType T) { 3035 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) 3036 if (CXXRecordDecl *Definition = Record->getDefinition()) 3037 if (Definition->isDynamicClass()) 3038 return true; 3039 3040 return false; 3041} 3042 3043/// \brief If E is a sizeof expression, returns its argument expression, 3044/// otherwise returns NULL. 3045static const Expr *getSizeOfExprArg(const Expr* E) { 3046 if (const UnaryExprOrTypeTraitExpr *SizeOf = 3047 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 3048 if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType()) 3049 return SizeOf->getArgumentExpr()->IgnoreParenImpCasts(); 3050 3051 return 0; 3052} 3053 3054/// \brief If E is a sizeof expression, returns its argument type. 3055static QualType getSizeOfArgType(const Expr* E) { 3056 if (const UnaryExprOrTypeTraitExpr *SizeOf = 3057 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 3058 if (SizeOf->getKind() == clang::UETT_SizeOf) 3059 return SizeOf->getTypeOfArgument(); 3060 3061 return QualType(); 3062} 3063 3064/// \brief Check for dangerous or invalid arguments to memset(). 3065/// 3066/// This issues warnings on known problematic, dangerous or unspecified 3067/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp' 3068/// function calls. 3069/// 3070/// \param Call The call expression to diagnose. 3071void Sema::CheckMemaccessArguments(const CallExpr *Call, 3072 unsigned BId, 3073 IdentifierInfo *FnName) { 3074 assert(BId != 0); 3075 3076 // It is possible to have a non-standard definition of memset. Validate 3077 // we have enough arguments, and if not, abort further checking. 3078 unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3); 3079 if (Call->getNumArgs() < ExpectedNumArgs) 3080 return; 3081 3082 unsigned LastArg = (BId == Builtin::BImemset || 3083 BId == Builtin::BIstrndup ? 1 : 2); 3084 unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2); 3085 const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts(); 3086 3087 // We have special checking when the length is a sizeof expression. 3088 QualType SizeOfArgTy = getSizeOfArgType(LenExpr); 3089 const Expr *SizeOfArg = getSizeOfExprArg(LenExpr); 3090 llvm::FoldingSetNodeID SizeOfArgID; 3091 3092 for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) { 3093 const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts(); 3094 SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange(); 3095 3096 QualType DestTy = Dest->getType(); 3097 if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) { 3098 QualType PointeeTy = DestPtrTy->getPointeeType(); 3099 3100 // Never warn about void type pointers. This can be used to suppress 3101 // false positives. 3102 if (PointeeTy->isVoidType()) 3103 continue; 3104 3105 // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by 3106 // actually comparing the expressions for equality. Because computing the 3107 // expression IDs can be expensive, we only do this if the diagnostic is 3108 // enabled. 3109 if (SizeOfArg && 3110 Diags.getDiagnosticLevel(diag::warn_sizeof_pointer_expr_memaccess, 3111 SizeOfArg->getExprLoc())) { 3112 // We only compute IDs for expressions if the warning is enabled, and 3113 // cache the sizeof arg's ID. 3114 if (SizeOfArgID == llvm::FoldingSetNodeID()) 3115 SizeOfArg->Profile(SizeOfArgID, Context, true); 3116 llvm::FoldingSetNodeID DestID; 3117 Dest->Profile(DestID, Context, true); 3118 if (DestID == SizeOfArgID) { 3119 // TODO: For strncpy() and friends, this could suggest sizeof(dst) 3120 // over sizeof(src) as well. 3121 unsigned ActionIdx = 0; // Default is to suggest dereferencing. 3122 StringRef ReadableName = FnName->getName(); 3123 3124 if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest)) 3125 if (UnaryOp->getOpcode() == UO_AddrOf) 3126 ActionIdx = 1; // If its an address-of operator, just remove it. 3127 if (Context.getTypeSize(PointeeTy) == Context.getCharWidth()) 3128 ActionIdx = 2; // If the pointee's size is sizeof(char), 3129 // suggest an explicit length. 3130 3131 // If the function is defined as a builtin macro, do not show macro 3132 // expansion. 3133 SourceLocation SL = SizeOfArg->getExprLoc(); 3134 SourceRange DSR = Dest->getSourceRange(); 3135 SourceRange SSR = SizeOfArg->getSourceRange(); 3136 SourceManager &SM = PP.getSourceManager(); 3137 3138 if (SM.isMacroArgExpansion(SL)) { 3139 ReadableName = Lexer::getImmediateMacroName(SL, SM, LangOpts); 3140 SL = SM.getSpellingLoc(SL); 3141 DSR = SourceRange(SM.getSpellingLoc(DSR.getBegin()), 3142 SM.getSpellingLoc(DSR.getEnd())); 3143 SSR = SourceRange(SM.getSpellingLoc(SSR.getBegin()), 3144 SM.getSpellingLoc(SSR.getEnd())); 3145 } 3146 3147 DiagRuntimeBehavior(SL, SizeOfArg, 3148 PDiag(diag::warn_sizeof_pointer_expr_memaccess) 3149 << ReadableName 3150 << PointeeTy 3151 << DestTy 3152 << DSR 3153 << SSR); 3154 DiagRuntimeBehavior(SL, SizeOfArg, 3155 PDiag(diag::warn_sizeof_pointer_expr_memaccess_note) 3156 << ActionIdx 3157 << SSR); 3158 3159 break; 3160 } 3161 } 3162 3163 // Also check for cases where the sizeof argument is the exact same 3164 // type as the memory argument, and where it points to a user-defined 3165 // record type. 3166 if (SizeOfArgTy != QualType()) { 3167 if (PointeeTy->isRecordType() && 3168 Context.typesAreCompatible(SizeOfArgTy, DestTy)) { 3169 DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest, 3170 PDiag(diag::warn_sizeof_pointer_type_memaccess) 3171 << FnName << SizeOfArgTy << ArgIdx 3172 << PointeeTy << Dest->getSourceRange() 3173 << LenExpr->getSourceRange()); 3174 break; 3175 } 3176 } 3177 3178 // Always complain about dynamic classes. 3179 if (isDynamicClassType(PointeeTy)) { 3180 3181 unsigned OperationType = 0; 3182 // "overwritten" if we're warning about the destination for any call 3183 // but memcmp; otherwise a verb appropriate to the call. 3184 if (ArgIdx != 0 || BId == Builtin::BImemcmp) { 3185 if (BId == Builtin::BImemcpy) 3186 OperationType = 1; 3187 else if(BId == Builtin::BImemmove) 3188 OperationType = 2; 3189 else if (BId == Builtin::BImemcmp) 3190 OperationType = 3; 3191 } 3192 3193 DiagRuntimeBehavior( 3194 Dest->getExprLoc(), Dest, 3195 PDiag(diag::warn_dyn_class_memaccess) 3196 << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx) 3197 << FnName << PointeeTy 3198 << OperationType 3199 << Call->getCallee()->getSourceRange()); 3200 } else if (PointeeTy.hasNonTrivialObjCLifetime() && 3201 BId != Builtin::BImemset) 3202 DiagRuntimeBehavior( 3203 Dest->getExprLoc(), Dest, 3204 PDiag(diag::warn_arc_object_memaccess) 3205 << ArgIdx << FnName << PointeeTy 3206 << Call->getCallee()->getSourceRange()); 3207 else 3208 continue; 3209 3210 DiagRuntimeBehavior( 3211 Dest->getExprLoc(), Dest, 3212 PDiag(diag::note_bad_memaccess_silence) 3213 << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)")); 3214 break; 3215 } 3216 } 3217} 3218 3219// A little helper routine: ignore addition and subtraction of integer literals. 3220// This intentionally does not ignore all integer constant expressions because 3221// we don't want to remove sizeof(). 3222static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) { 3223 Ex = Ex->IgnoreParenCasts(); 3224 3225 for (;;) { 3226 const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex); 3227 if (!BO || !BO->isAdditiveOp()) 3228 break; 3229 3230 const Expr *RHS = BO->getRHS()->IgnoreParenCasts(); 3231 const Expr *LHS = BO->getLHS()->IgnoreParenCasts(); 3232 3233 if (isa<IntegerLiteral>(RHS)) 3234 Ex = LHS; 3235 else if (isa<IntegerLiteral>(LHS)) 3236 Ex = RHS; 3237 else 3238 break; 3239 } 3240 3241 return Ex; 3242} 3243 3244static bool isConstantSizeArrayWithMoreThanOneElement(QualType Ty, 3245 ASTContext &Context) { 3246 // Only handle constant-sized or VLAs, but not flexible members. 3247 if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(Ty)) { 3248 // Only issue the FIXIT for arrays of size > 1. 3249 if (CAT->getSize().getSExtValue() <= 1) 3250 return false; 3251 } else if (!Ty->isVariableArrayType()) { 3252 return false; 3253 } 3254 return true; 3255} 3256 3257// Warn if the user has made the 'size' argument to strlcpy or strlcat 3258// be the size of the source, instead of the destination. 3259void Sema::CheckStrlcpycatArguments(const CallExpr *Call, 3260 IdentifierInfo *FnName) { 3261 3262 // Don't crash if the user has the wrong number of arguments 3263 if (Call->getNumArgs() != 3) 3264 return; 3265 3266 const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context); 3267 const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context); 3268 const Expr *CompareWithSrc = NULL; 3269 3270 // Look for 'strlcpy(dst, x, sizeof(x))' 3271 if (const Expr *Ex = getSizeOfExprArg(SizeArg)) 3272 CompareWithSrc = Ex; 3273 else { 3274 // Look for 'strlcpy(dst, x, strlen(x))' 3275 if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) { 3276 if (SizeCall->isBuiltinCall() == Builtin::BIstrlen 3277 && SizeCall->getNumArgs() == 1) 3278 CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context); 3279 } 3280 } 3281 3282 if (!CompareWithSrc) 3283 return; 3284 3285 // Determine if the argument to sizeof/strlen is equal to the source 3286 // argument. In principle there's all kinds of things you could do 3287 // here, for instance creating an == expression and evaluating it with 3288 // EvaluateAsBooleanCondition, but this uses a more direct technique: 3289 const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg); 3290 if (!SrcArgDRE) 3291 return; 3292 3293 const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc); 3294 if (!CompareWithSrcDRE || 3295 SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl()) 3296 return; 3297 3298 const Expr *OriginalSizeArg = Call->getArg(2); 3299 Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size) 3300 << OriginalSizeArg->getSourceRange() << FnName; 3301 3302 // Output a FIXIT hint if the destination is an array (rather than a 3303 // pointer to an array). This could be enhanced to handle some 3304 // pointers if we know the actual size, like if DstArg is 'array+2' 3305 // we could say 'sizeof(array)-2'. 3306 const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts(); 3307 if (!isConstantSizeArrayWithMoreThanOneElement(DstArg->getType(), Context)) 3308 return; 3309 3310 SmallString<128> sizeString; 3311 llvm::raw_svector_ostream OS(sizeString); 3312 OS << "sizeof("; 3313 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3314 OS << ")"; 3315 3316 Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size) 3317 << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(), 3318 OS.str()); 3319} 3320 3321/// Check if two expressions refer to the same declaration. 3322static bool referToTheSameDecl(const Expr *E1, const Expr *E2) { 3323 if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1)) 3324 if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2)) 3325 return D1->getDecl() == D2->getDecl(); 3326 return false; 3327} 3328 3329static const Expr *getStrlenExprArg(const Expr *E) { 3330 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 3331 const FunctionDecl *FD = CE->getDirectCallee(); 3332 if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen) 3333 return 0; 3334 return CE->getArg(0)->IgnoreParenCasts(); 3335 } 3336 return 0; 3337} 3338 3339// Warn on anti-patterns as the 'size' argument to strncat. 3340// The correct size argument should look like following: 3341// strncat(dst, src, sizeof(dst) - strlen(dest) - 1); 3342void Sema::CheckStrncatArguments(const CallExpr *CE, 3343 IdentifierInfo *FnName) { 3344 // Don't crash if the user has the wrong number of arguments. 3345 if (CE->getNumArgs() < 3) 3346 return; 3347 const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts(); 3348 const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts(); 3349 const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts(); 3350 3351 // Identify common expressions, which are wrongly used as the size argument 3352 // to strncat and may lead to buffer overflows. 3353 unsigned PatternType = 0; 3354 if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) { 3355 // - sizeof(dst) 3356 if (referToTheSameDecl(SizeOfArg, DstArg)) 3357 PatternType = 1; 3358 // - sizeof(src) 3359 else if (referToTheSameDecl(SizeOfArg, SrcArg)) 3360 PatternType = 2; 3361 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) { 3362 if (BE->getOpcode() == BO_Sub) { 3363 const Expr *L = BE->getLHS()->IgnoreParenCasts(); 3364 const Expr *R = BE->getRHS()->IgnoreParenCasts(); 3365 // - sizeof(dst) - strlen(dst) 3366 if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) && 3367 referToTheSameDecl(DstArg, getStrlenExprArg(R))) 3368 PatternType = 1; 3369 // - sizeof(src) - (anything) 3370 else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L))) 3371 PatternType = 2; 3372 } 3373 } 3374 3375 if (PatternType == 0) 3376 return; 3377 3378 // Generate the diagnostic. 3379 SourceLocation SL = LenArg->getLocStart(); 3380 SourceRange SR = LenArg->getSourceRange(); 3381 SourceManager &SM = PP.getSourceManager(); 3382 3383 // If the function is defined as a builtin macro, do not show macro expansion. 3384 if (SM.isMacroArgExpansion(SL)) { 3385 SL = SM.getSpellingLoc(SL); 3386 SR = SourceRange(SM.getSpellingLoc(SR.getBegin()), 3387 SM.getSpellingLoc(SR.getEnd())); 3388 } 3389 3390 // Check if the destination is an array (rather than a pointer to an array). 3391 QualType DstTy = DstArg->getType(); 3392 bool isKnownSizeArray = isConstantSizeArrayWithMoreThanOneElement(DstTy, 3393 Context); 3394 if (!isKnownSizeArray) { 3395 if (PatternType == 1) 3396 Diag(SL, diag::warn_strncat_wrong_size) << SR; 3397 else 3398 Diag(SL, diag::warn_strncat_src_size) << SR; 3399 return; 3400 } 3401 3402 if (PatternType == 1) 3403 Diag(SL, diag::warn_strncat_large_size) << SR; 3404 else 3405 Diag(SL, diag::warn_strncat_src_size) << SR; 3406 3407 SmallString<128> sizeString; 3408 llvm::raw_svector_ostream OS(sizeString); 3409 OS << "sizeof("; 3410 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3411 OS << ") - "; 3412 OS << "strlen("; 3413 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3414 OS << ") - 1"; 3415 3416 Diag(SL, diag::note_strncat_wrong_size) 3417 << FixItHint::CreateReplacement(SR, OS.str()); 3418} 3419 3420//===--- CHECK: Return Address of Stack Variable --------------------------===// 3421 3422static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3423 Decl *ParentDecl); 3424static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars, 3425 Decl *ParentDecl); 3426 3427/// CheckReturnStackAddr - Check if a return statement returns the address 3428/// of a stack variable. 3429void 3430Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType, 3431 SourceLocation ReturnLoc) { 3432 3433 Expr *stackE = 0; 3434 SmallVector<DeclRefExpr *, 8> refVars; 3435 3436 // Perform checking for returned stack addresses, local blocks, 3437 // label addresses or references to temporaries. 3438 if (lhsType->isPointerType() || 3439 (!getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) { 3440 stackE = EvalAddr(RetValExp, refVars, /*ParentDecl=*/0); 3441 } else if (lhsType->isReferenceType()) { 3442 stackE = EvalVal(RetValExp, refVars, /*ParentDecl=*/0); 3443 } 3444 3445 if (stackE == 0) 3446 return; // Nothing suspicious was found. 3447 3448 SourceLocation diagLoc; 3449 SourceRange diagRange; 3450 if (refVars.empty()) { 3451 diagLoc = stackE->getLocStart(); 3452 diagRange = stackE->getSourceRange(); 3453 } else { 3454 // We followed through a reference variable. 'stackE' contains the 3455 // problematic expression but we will warn at the return statement pointing 3456 // at the reference variable. We will later display the "trail" of 3457 // reference variables using notes. 3458 diagLoc = refVars[0]->getLocStart(); 3459 diagRange = refVars[0]->getSourceRange(); 3460 } 3461 3462 if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var. 3463 Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref 3464 : diag::warn_ret_stack_addr) 3465 << DR->getDecl()->getDeclName() << diagRange; 3466 } else if (isa<BlockExpr>(stackE)) { // local block. 3467 Diag(diagLoc, diag::err_ret_local_block) << diagRange; 3468 } else if (isa<AddrLabelExpr>(stackE)) { // address of label. 3469 Diag(diagLoc, diag::warn_ret_addr_label) << diagRange; 3470 } else { // local temporary. 3471 Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref 3472 : diag::warn_ret_local_temp_addr) 3473 << diagRange; 3474 } 3475 3476 // Display the "trail" of reference variables that we followed until we 3477 // found the problematic expression using notes. 3478 for (unsigned i = 0, e = refVars.size(); i != e; ++i) { 3479 VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl()); 3480 // If this var binds to another reference var, show the range of the next 3481 // var, otherwise the var binds to the problematic expression, in which case 3482 // show the range of the expression. 3483 SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange() 3484 : stackE->getSourceRange(); 3485 Diag(VD->getLocation(), diag::note_ref_var_local_bind) 3486 << VD->getDeclName() << range; 3487 } 3488} 3489 3490/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that 3491/// check if the expression in a return statement evaluates to an address 3492/// to a location on the stack, a local block, an address of a label, or a 3493/// reference to local temporary. The recursion is used to traverse the 3494/// AST of the return expression, with recursion backtracking when we 3495/// encounter a subexpression that (1) clearly does not lead to one of the 3496/// above problematic expressions (2) is something we cannot determine leads to 3497/// a problematic expression based on such local checking. 3498/// 3499/// Both EvalAddr and EvalVal follow through reference variables to evaluate 3500/// the expression that they point to. Such variables are added to the 3501/// 'refVars' vector so that we know what the reference variable "trail" was. 3502/// 3503/// EvalAddr processes expressions that are pointers that are used as 3504/// references (and not L-values). EvalVal handles all other values. 3505/// At the base case of the recursion is a check for the above problematic 3506/// expressions. 3507/// 3508/// This implementation handles: 3509/// 3510/// * pointer-to-pointer casts 3511/// * implicit conversions from array references to pointers 3512/// * taking the address of fields 3513/// * arbitrary interplay between "&" and "*" operators 3514/// * pointer arithmetic from an address of a stack variable 3515/// * taking the address of an array element where the array is on the stack 3516static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3517 Decl *ParentDecl) { 3518 if (E->isTypeDependent()) 3519 return NULL; 3520 3521 // We should only be called for evaluating pointer expressions. 3522 assert((E->getType()->isAnyPointerType() || 3523 E->getType()->isBlockPointerType() || 3524 E->getType()->isObjCQualifiedIdType()) && 3525 "EvalAddr only works on pointers"); 3526 3527 E = E->IgnoreParens(); 3528 3529 // Our "symbolic interpreter" is just a dispatch off the currently 3530 // viewed AST node. We then recursively traverse the AST by calling 3531 // EvalAddr and EvalVal appropriately. 3532 switch (E->getStmtClass()) { 3533 case Stmt::DeclRefExprClass: { 3534 DeclRefExpr *DR = cast<DeclRefExpr>(E); 3535 3536 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) 3537 // If this is a reference variable, follow through to the expression that 3538 // it points to. 3539 if (V->hasLocalStorage() && 3540 V->getType()->isReferenceType() && V->hasInit()) { 3541 // Add the reference variable to the "trail". 3542 refVars.push_back(DR); 3543 return EvalAddr(V->getInit(), refVars, ParentDecl); 3544 } 3545 3546 return NULL; 3547 } 3548 3549 case Stmt::UnaryOperatorClass: { 3550 // The only unary operator that make sense to handle here 3551 // is AddrOf. All others don't make sense as pointers. 3552 UnaryOperator *U = cast<UnaryOperator>(E); 3553 3554 if (U->getOpcode() == UO_AddrOf) 3555 return EvalVal(U->getSubExpr(), refVars, ParentDecl); 3556 else 3557 return NULL; 3558 } 3559 3560 case Stmt::BinaryOperatorClass: { 3561 // Handle pointer arithmetic. All other binary operators are not valid 3562 // in this context. 3563 BinaryOperator *B = cast<BinaryOperator>(E); 3564 BinaryOperatorKind op = B->getOpcode(); 3565 3566 if (op != BO_Add && op != BO_Sub) 3567 return NULL; 3568 3569 Expr *Base = B->getLHS(); 3570 3571 // Determine which argument is the real pointer base. It could be 3572 // the RHS argument instead of the LHS. 3573 if (!Base->getType()->isPointerType()) Base = B->getRHS(); 3574 3575 assert (Base->getType()->isPointerType()); 3576 return EvalAddr(Base, refVars, ParentDecl); 3577 } 3578 3579 // For conditional operators we need to see if either the LHS or RHS are 3580 // valid DeclRefExpr*s. If one of them is valid, we return it. 3581 case Stmt::ConditionalOperatorClass: { 3582 ConditionalOperator *C = cast<ConditionalOperator>(E); 3583 3584 // Handle the GNU extension for missing LHS. 3585 if (Expr *lhsExpr = C->getLHS()) { 3586 // In C++, we can have a throw-expression, which has 'void' type. 3587 if (!lhsExpr->getType()->isVoidType()) 3588 if (Expr* LHS = EvalAddr(lhsExpr, refVars, ParentDecl)) 3589 return LHS; 3590 } 3591 3592 // In C++, we can have a throw-expression, which has 'void' type. 3593 if (C->getRHS()->getType()->isVoidType()) 3594 return NULL; 3595 3596 return EvalAddr(C->getRHS(), refVars, ParentDecl); 3597 } 3598 3599 case Stmt::BlockExprClass: 3600 if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures()) 3601 return E; // local block. 3602 return NULL; 3603 3604 case Stmt::AddrLabelExprClass: 3605 return E; // address of label. 3606 3607 case Stmt::ExprWithCleanupsClass: 3608 return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars, 3609 ParentDecl); 3610 3611 // For casts, we need to handle conversions from arrays to 3612 // pointer values, and pointer-to-pointer conversions. 3613 case Stmt::ImplicitCastExprClass: 3614 case Stmt::CStyleCastExprClass: 3615 case Stmt::CXXFunctionalCastExprClass: 3616 case Stmt::ObjCBridgedCastExprClass: 3617 case Stmt::CXXStaticCastExprClass: 3618 case Stmt::CXXDynamicCastExprClass: 3619 case Stmt::CXXConstCastExprClass: 3620 case Stmt::CXXReinterpretCastExprClass: { 3621 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr(); 3622 switch (cast<CastExpr>(E)->getCastKind()) { 3623 case CK_BitCast: 3624 case CK_LValueToRValue: 3625 case CK_NoOp: 3626 case CK_BaseToDerived: 3627 case CK_DerivedToBase: 3628 case CK_UncheckedDerivedToBase: 3629 case CK_Dynamic: 3630 case CK_CPointerToObjCPointerCast: 3631 case CK_BlockPointerToObjCPointerCast: 3632 case CK_AnyPointerToBlockPointerCast: 3633 return EvalAddr(SubExpr, refVars, ParentDecl); 3634 3635 case CK_ArrayToPointerDecay: 3636 return EvalVal(SubExpr, refVars, ParentDecl); 3637 3638 default: 3639 return 0; 3640 } 3641 } 3642 3643 case Stmt::MaterializeTemporaryExprClass: 3644 if (Expr *Result = EvalAddr( 3645 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 3646 refVars, ParentDecl)) 3647 return Result; 3648 3649 return E; 3650 3651 // Everything else: we simply don't reason about them. 3652 default: 3653 return NULL; 3654 } 3655} 3656 3657 3658/// EvalVal - This function is complements EvalAddr in the mutual recursion. 3659/// See the comments for EvalAddr for more details. 3660static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3661 Decl *ParentDecl) { 3662do { 3663 // We should only be called for evaluating non-pointer expressions, or 3664 // expressions with a pointer type that are not used as references but instead 3665 // are l-values (e.g., DeclRefExpr with a pointer type). 3666 3667 // Our "symbolic interpreter" is just a dispatch off the currently 3668 // viewed AST node. We then recursively traverse the AST by calling 3669 // EvalAddr and EvalVal appropriately. 3670 3671 E = E->IgnoreParens(); 3672 switch (E->getStmtClass()) { 3673 case Stmt::ImplicitCastExprClass: { 3674 ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E); 3675 if (IE->getValueKind() == VK_LValue) { 3676 E = IE->getSubExpr(); 3677 continue; 3678 } 3679 return NULL; 3680 } 3681 3682 case Stmt::ExprWithCleanupsClass: 3683 return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,ParentDecl); 3684 3685 case Stmt::DeclRefExprClass: { 3686 // When we hit a DeclRefExpr we are looking at code that refers to a 3687 // variable's name. If it's not a reference variable we check if it has 3688 // local storage within the function, and if so, return the expression. 3689 DeclRefExpr *DR = cast<DeclRefExpr>(E); 3690 3691 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) { 3692 // Check if it refers to itself, e.g. "int& i = i;". 3693 if (V == ParentDecl) 3694 return DR; 3695 3696 if (V->hasLocalStorage()) { 3697 if (!V->getType()->isReferenceType()) 3698 return DR; 3699 3700 // Reference variable, follow through to the expression that 3701 // it points to. 3702 if (V->hasInit()) { 3703 // Add the reference variable to the "trail". 3704 refVars.push_back(DR); 3705 return EvalVal(V->getInit(), refVars, V); 3706 } 3707 } 3708 } 3709 3710 return NULL; 3711 } 3712 3713 case Stmt::UnaryOperatorClass: { 3714 // The only unary operator that make sense to handle here 3715 // is Deref. All others don't resolve to a "name." This includes 3716 // handling all sorts of rvalues passed to a unary operator. 3717 UnaryOperator *U = cast<UnaryOperator>(E); 3718 3719 if (U->getOpcode() == UO_Deref) 3720 return EvalAddr(U->getSubExpr(), refVars, ParentDecl); 3721 3722 return NULL; 3723 } 3724 3725 case Stmt::ArraySubscriptExprClass: { 3726 // Array subscripts are potential references to data on the stack. We 3727 // retrieve the DeclRefExpr* for the array variable if it indeed 3728 // has local storage. 3729 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars,ParentDecl); 3730 } 3731 3732 case Stmt::ConditionalOperatorClass: { 3733 // For conditional operators we need to see if either the LHS or RHS are 3734 // non-NULL Expr's. If one is non-NULL, we return it. 3735 ConditionalOperator *C = cast<ConditionalOperator>(E); 3736 3737 // Handle the GNU extension for missing LHS. 3738 if (Expr *lhsExpr = C->getLHS()) 3739 if (Expr *LHS = EvalVal(lhsExpr, refVars, ParentDecl)) 3740 return LHS; 3741 3742 return EvalVal(C->getRHS(), refVars, ParentDecl); 3743 } 3744 3745 // Accesses to members are potential references to data on the stack. 3746 case Stmt::MemberExprClass: { 3747 MemberExpr *M = cast<MemberExpr>(E); 3748 3749 // Check for indirect access. We only want direct field accesses. 3750 if (M->isArrow()) 3751 return NULL; 3752 3753 // Check whether the member type is itself a reference, in which case 3754 // we're not going to refer to the member, but to what the member refers to. 3755 if (M->getMemberDecl()->getType()->isReferenceType()) 3756 return NULL; 3757 3758 return EvalVal(M->getBase(), refVars, ParentDecl); 3759 } 3760 3761 case Stmt::MaterializeTemporaryExprClass: 3762 if (Expr *Result = EvalVal( 3763 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 3764 refVars, ParentDecl)) 3765 return Result; 3766 3767 return E; 3768 3769 default: 3770 // Check that we don't return or take the address of a reference to a 3771 // temporary. This is only useful in C++. 3772 if (!E->isTypeDependent() && E->isRValue()) 3773 return E; 3774 3775 // Everything else: we simply don't reason about them. 3776 return NULL; 3777 } 3778} while (true); 3779} 3780 3781//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===// 3782 3783/// Check for comparisons of floating point operands using != and ==. 3784/// Issue a warning if these are no self-comparisons, as they are not likely 3785/// to do what the programmer intended. 3786void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) { 3787 Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts(); 3788 Expr* RightExprSansParen = RHS->IgnoreParenImpCasts(); 3789 3790 // Special case: check for x == x (which is OK). 3791 // Do not emit warnings for such cases. 3792 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen)) 3793 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen)) 3794 if (DRL->getDecl() == DRR->getDecl()) 3795 return; 3796 3797 3798 // Special case: check for comparisons against literals that can be exactly 3799 // represented by APFloat. In such cases, do not emit a warning. This 3800 // is a heuristic: often comparison against such literals are used to 3801 // detect if a value in a variable has not changed. This clearly can 3802 // lead to false negatives. 3803 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) { 3804 if (FLL->isExact()) 3805 return; 3806 } else 3807 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)) 3808 if (FLR->isExact()) 3809 return; 3810 3811 // Check for comparisons with builtin types. 3812 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen)) 3813 if (CL->isBuiltinCall()) 3814 return; 3815 3816 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen)) 3817 if (CR->isBuiltinCall()) 3818 return; 3819 3820 // Emit the diagnostic. 3821 Diag(Loc, diag::warn_floatingpoint_eq) 3822 << LHS->getSourceRange() << RHS->getSourceRange(); 3823} 3824 3825//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===// 3826//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===// 3827 3828namespace { 3829 3830/// Structure recording the 'active' range of an integer-valued 3831/// expression. 3832struct IntRange { 3833 /// The number of bits active in the int. 3834 unsigned Width; 3835 3836 /// True if the int is known not to have negative values. 3837 bool NonNegative; 3838 3839 IntRange(unsigned Width, bool NonNegative) 3840 : Width(Width), NonNegative(NonNegative) 3841 {} 3842 3843 /// Returns the range of the bool type. 3844 static IntRange forBoolType() { 3845 return IntRange(1, true); 3846 } 3847 3848 /// Returns the range of an opaque value of the given integral type. 3849 static IntRange forValueOfType(ASTContext &C, QualType T) { 3850 return forValueOfCanonicalType(C, 3851 T->getCanonicalTypeInternal().getTypePtr()); 3852 } 3853 3854 /// Returns the range of an opaque value of a canonical integral type. 3855 static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) { 3856 assert(T->isCanonicalUnqualified()); 3857 3858 if (const VectorType *VT = dyn_cast<VectorType>(T)) 3859 T = VT->getElementType().getTypePtr(); 3860 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 3861 T = CT->getElementType().getTypePtr(); 3862 3863 // For enum types, use the known bit width of the enumerators. 3864 if (const EnumType *ET = dyn_cast<EnumType>(T)) { 3865 EnumDecl *Enum = ET->getDecl(); 3866 if (!Enum->isCompleteDefinition()) 3867 return IntRange(C.getIntWidth(QualType(T, 0)), false); 3868 3869 unsigned NumPositive = Enum->getNumPositiveBits(); 3870 unsigned NumNegative = Enum->getNumNegativeBits(); 3871 3872 return IntRange(std::max(NumPositive, NumNegative), NumNegative == 0); 3873 } 3874 3875 const BuiltinType *BT = cast<BuiltinType>(T); 3876 assert(BT->isInteger()); 3877 3878 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 3879 } 3880 3881 /// Returns the "target" range of a canonical integral type, i.e. 3882 /// the range of values expressible in the type. 3883 /// 3884 /// This matches forValueOfCanonicalType except that enums have the 3885 /// full range of their type, not the range of their enumerators. 3886 static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) { 3887 assert(T->isCanonicalUnqualified()); 3888 3889 if (const VectorType *VT = dyn_cast<VectorType>(T)) 3890 T = VT->getElementType().getTypePtr(); 3891 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 3892 T = CT->getElementType().getTypePtr(); 3893 if (const EnumType *ET = dyn_cast<EnumType>(T)) 3894 T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr(); 3895 3896 const BuiltinType *BT = cast<BuiltinType>(T); 3897 assert(BT->isInteger()); 3898 3899 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 3900 } 3901 3902 /// Returns the supremum of two ranges: i.e. their conservative merge. 3903 static IntRange join(IntRange L, IntRange R) { 3904 return IntRange(std::max(L.Width, R.Width), 3905 L.NonNegative && R.NonNegative); 3906 } 3907 3908 /// Returns the infinum of two ranges: i.e. their aggressive merge. 3909 static IntRange meet(IntRange L, IntRange R) { 3910 return IntRange(std::min(L.Width, R.Width), 3911 L.NonNegative || R.NonNegative); 3912 } 3913}; 3914 3915static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, 3916 unsigned MaxWidth) { 3917 if (value.isSigned() && value.isNegative()) 3918 return IntRange(value.getMinSignedBits(), false); 3919 3920 if (value.getBitWidth() > MaxWidth) 3921 value = value.trunc(MaxWidth); 3922 3923 // isNonNegative() just checks the sign bit without considering 3924 // signedness. 3925 return IntRange(value.getActiveBits(), true); 3926} 3927 3928static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty, 3929 unsigned MaxWidth) { 3930 if (result.isInt()) 3931 return GetValueRange(C, result.getInt(), MaxWidth); 3932 3933 if (result.isVector()) { 3934 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth); 3935 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) { 3936 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth); 3937 R = IntRange::join(R, El); 3938 } 3939 return R; 3940 } 3941 3942 if (result.isComplexInt()) { 3943 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth); 3944 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth); 3945 return IntRange::join(R, I); 3946 } 3947 3948 // This can happen with lossless casts to intptr_t of "based" lvalues. 3949 // Assume it might use arbitrary bits. 3950 // FIXME: The only reason we need to pass the type in here is to get 3951 // the sign right on this one case. It would be nice if APValue 3952 // preserved this. 3953 assert(result.isLValue() || result.isAddrLabelDiff()); 3954 return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType()); 3955} 3956 3957/// Pseudo-evaluate the given integer expression, estimating the 3958/// range of values it might take. 3959/// 3960/// \param MaxWidth - the width to which the value will be truncated 3961static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) { 3962 E = E->IgnoreParens(); 3963 3964 // Try a full evaluation first. 3965 Expr::EvalResult result; 3966 if (E->EvaluateAsRValue(result, C)) 3967 return GetValueRange(C, result.Val, E->getType(), MaxWidth); 3968 3969 // I think we only want to look through implicit casts here; if the 3970 // user has an explicit widening cast, we should treat the value as 3971 // being of the new, wider type. 3972 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) { 3973 if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue) 3974 return GetExprRange(C, CE->getSubExpr(), MaxWidth); 3975 3976 IntRange OutputTypeRange = IntRange::forValueOfType(C, CE->getType()); 3977 3978 bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast); 3979 3980 // Assume that non-integer casts can span the full range of the type. 3981 if (!isIntegerCast) 3982 return OutputTypeRange; 3983 3984 IntRange SubRange 3985 = GetExprRange(C, CE->getSubExpr(), 3986 std::min(MaxWidth, OutputTypeRange.Width)); 3987 3988 // Bail out if the subexpr's range is as wide as the cast type. 3989 if (SubRange.Width >= OutputTypeRange.Width) 3990 return OutputTypeRange; 3991 3992 // Otherwise, we take the smaller width, and we're non-negative if 3993 // either the output type or the subexpr is. 3994 return IntRange(SubRange.Width, 3995 SubRange.NonNegative || OutputTypeRange.NonNegative); 3996 } 3997 3998 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 3999 // If we can fold the condition, just take that operand. 4000 bool CondResult; 4001 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C)) 4002 return GetExprRange(C, CondResult ? CO->getTrueExpr() 4003 : CO->getFalseExpr(), 4004 MaxWidth); 4005 4006 // Otherwise, conservatively merge. 4007 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth); 4008 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth); 4009 return IntRange::join(L, R); 4010 } 4011 4012 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 4013 switch (BO->getOpcode()) { 4014 4015 // Boolean-valued operations are single-bit and positive. 4016 case BO_LAnd: 4017 case BO_LOr: 4018 case BO_LT: 4019 case BO_GT: 4020 case BO_LE: 4021 case BO_GE: 4022 case BO_EQ: 4023 case BO_NE: 4024 return IntRange::forBoolType(); 4025 4026 // The type of the assignments is the type of the LHS, so the RHS 4027 // is not necessarily the same type. 4028 case BO_MulAssign: 4029 case BO_DivAssign: 4030 case BO_RemAssign: 4031 case BO_AddAssign: 4032 case BO_SubAssign: 4033 case BO_XorAssign: 4034 case BO_OrAssign: 4035 // TODO: bitfields? 4036 return IntRange::forValueOfType(C, E->getType()); 4037 4038 // Simple assignments just pass through the RHS, which will have 4039 // been coerced to the LHS type. 4040 case BO_Assign: 4041 // TODO: bitfields? 4042 return GetExprRange(C, BO->getRHS(), MaxWidth); 4043 4044 // Operations with opaque sources are black-listed. 4045 case BO_PtrMemD: 4046 case BO_PtrMemI: 4047 return IntRange::forValueOfType(C, E->getType()); 4048 4049 // Bitwise-and uses the *infinum* of the two source ranges. 4050 case BO_And: 4051 case BO_AndAssign: 4052 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth), 4053 GetExprRange(C, BO->getRHS(), MaxWidth)); 4054 4055 // Left shift gets black-listed based on a judgement call. 4056 case BO_Shl: 4057 // ...except that we want to treat '1 << (blah)' as logically 4058 // positive. It's an important idiom. 4059 if (IntegerLiteral *I 4060 = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) { 4061 if (I->getValue() == 1) { 4062 IntRange R = IntRange::forValueOfType(C, E->getType()); 4063 return IntRange(R.Width, /*NonNegative*/ true); 4064 } 4065 } 4066 // fallthrough 4067 4068 case BO_ShlAssign: 4069 return IntRange::forValueOfType(C, E->getType()); 4070 4071 // Right shift by a constant can narrow its left argument. 4072 case BO_Shr: 4073 case BO_ShrAssign: { 4074 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 4075 4076 // If the shift amount is a positive constant, drop the width by 4077 // that much. 4078 llvm::APSInt shift; 4079 if (BO->getRHS()->isIntegerConstantExpr(shift, C) && 4080 shift.isNonNegative()) { 4081 unsigned zext = shift.getZExtValue(); 4082 if (zext >= L.Width) 4083 L.Width = (L.NonNegative ? 0 : 1); 4084 else 4085 L.Width -= zext; 4086 } 4087 4088 return L; 4089 } 4090 4091 // Comma acts as its right operand. 4092 case BO_Comma: 4093 return GetExprRange(C, BO->getRHS(), MaxWidth); 4094 4095 // Black-list pointer subtractions. 4096 case BO_Sub: 4097 if (BO->getLHS()->getType()->isPointerType()) 4098 return IntRange::forValueOfType(C, E->getType()); 4099 break; 4100 4101 // The width of a division result is mostly determined by the size 4102 // of the LHS. 4103 case BO_Div: { 4104 // Don't 'pre-truncate' the operands. 4105 unsigned opWidth = C.getIntWidth(E->getType()); 4106 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 4107 4108 // If the divisor is constant, use that. 4109 llvm::APSInt divisor; 4110 if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) { 4111 unsigned log2 = divisor.logBase2(); // floor(log_2(divisor)) 4112 if (log2 >= L.Width) 4113 L.Width = (L.NonNegative ? 0 : 1); 4114 else 4115 L.Width = std::min(L.Width - log2, MaxWidth); 4116 return L; 4117 } 4118 4119 // Otherwise, just use the LHS's width. 4120 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 4121 return IntRange(L.Width, L.NonNegative && R.NonNegative); 4122 } 4123 4124 // The result of a remainder can't be larger than the result of 4125 // either side. 4126 case BO_Rem: { 4127 // Don't 'pre-truncate' the operands. 4128 unsigned opWidth = C.getIntWidth(E->getType()); 4129 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 4130 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 4131 4132 IntRange meet = IntRange::meet(L, R); 4133 meet.Width = std::min(meet.Width, MaxWidth); 4134 return meet; 4135 } 4136 4137 // The default behavior is okay for these. 4138 case BO_Mul: 4139 case BO_Add: 4140 case BO_Xor: 4141 case BO_Or: 4142 break; 4143 } 4144 4145 // The default case is to treat the operation as if it were closed 4146 // on the narrowest type that encompasses both operands. 4147 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 4148 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth); 4149 return IntRange::join(L, R); 4150 } 4151 4152 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 4153 switch (UO->getOpcode()) { 4154 // Boolean-valued operations are white-listed. 4155 case UO_LNot: 4156 return IntRange::forBoolType(); 4157 4158 // Operations with opaque sources are black-listed. 4159 case UO_Deref: 4160 case UO_AddrOf: // should be impossible 4161 return IntRange::forValueOfType(C, E->getType()); 4162 4163 default: 4164 return GetExprRange(C, UO->getSubExpr(), MaxWidth); 4165 } 4166 } 4167 4168 if (dyn_cast<OffsetOfExpr>(E)) { 4169 IntRange::forValueOfType(C, E->getType()); 4170 } 4171 4172 if (FieldDecl *BitField = E->getBitField()) 4173 return IntRange(BitField->getBitWidthValue(C), 4174 BitField->getType()->isUnsignedIntegerOrEnumerationType()); 4175 4176 return IntRange::forValueOfType(C, E->getType()); 4177} 4178 4179static IntRange GetExprRange(ASTContext &C, Expr *E) { 4180 return GetExprRange(C, E, C.getIntWidth(E->getType())); 4181} 4182 4183/// Checks whether the given value, which currently has the given 4184/// source semantics, has the same value when coerced through the 4185/// target semantics. 4186static bool IsSameFloatAfterCast(const llvm::APFloat &value, 4187 const llvm::fltSemantics &Src, 4188 const llvm::fltSemantics &Tgt) { 4189 llvm::APFloat truncated = value; 4190 4191 bool ignored; 4192 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored); 4193 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored); 4194 4195 return truncated.bitwiseIsEqual(value); 4196} 4197 4198/// Checks whether the given value, which currently has the given 4199/// source semantics, has the same value when coerced through the 4200/// target semantics. 4201/// 4202/// The value might be a vector of floats (or a complex number). 4203static bool IsSameFloatAfterCast(const APValue &value, 4204 const llvm::fltSemantics &Src, 4205 const llvm::fltSemantics &Tgt) { 4206 if (value.isFloat()) 4207 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt); 4208 4209 if (value.isVector()) { 4210 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i) 4211 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt)) 4212 return false; 4213 return true; 4214 } 4215 4216 assert(value.isComplexFloat()); 4217 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) && 4218 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt)); 4219} 4220 4221static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC); 4222 4223static bool IsZero(Sema &S, Expr *E) { 4224 // Suppress cases where we are comparing against an enum constant. 4225 if (const DeclRefExpr *DR = 4226 dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts())) 4227 if (isa<EnumConstantDecl>(DR->getDecl())) 4228 return false; 4229 4230 // Suppress cases where the '0' value is expanded from a macro. 4231 if (E->getLocStart().isMacroID()) 4232 return false; 4233 4234 llvm::APSInt Value; 4235 return E->isIntegerConstantExpr(Value, S.Context) && Value == 0; 4236} 4237 4238static bool HasEnumType(Expr *E) { 4239 // Strip off implicit integral promotions. 4240 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 4241 if (ICE->getCastKind() != CK_IntegralCast && 4242 ICE->getCastKind() != CK_NoOp) 4243 break; 4244 E = ICE->getSubExpr(); 4245 } 4246 4247 return E->getType()->isEnumeralType(); 4248} 4249 4250static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) { 4251 BinaryOperatorKind op = E->getOpcode(); 4252 if (E->isValueDependent()) 4253 return; 4254 4255 if (op == BO_LT && IsZero(S, E->getRHS())) { 4256 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 4257 << "< 0" << "false" << HasEnumType(E->getLHS()) 4258 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4259 } else if (op == BO_GE && IsZero(S, E->getRHS())) { 4260 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 4261 << ">= 0" << "true" << HasEnumType(E->getLHS()) 4262 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4263 } else if (op == BO_GT && IsZero(S, E->getLHS())) { 4264 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 4265 << "0 >" << "false" << HasEnumType(E->getRHS()) 4266 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4267 } else if (op == BO_LE && IsZero(S, E->getLHS())) { 4268 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 4269 << "0 <=" << "true" << HasEnumType(E->getRHS()) 4270 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4271 } 4272} 4273 4274/// Analyze the operands of the given comparison. Implements the 4275/// fallback case from AnalyzeComparison. 4276static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) { 4277 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 4278 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 4279} 4280 4281/// \brief Implements -Wsign-compare. 4282/// 4283/// \param E the binary operator to check for warnings 4284static void AnalyzeComparison(Sema &S, BinaryOperator *E) { 4285 // The type the comparison is being performed in. 4286 QualType T = E->getLHS()->getType(); 4287 assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType()) 4288 && "comparison with mismatched types"); 4289 4290 // We don't do anything special if this isn't an unsigned integral 4291 // comparison: we're only interested in integral comparisons, and 4292 // signed comparisons only happen in cases we don't care to warn about. 4293 // 4294 // We also don't care about value-dependent expressions or expressions 4295 // whose result is a constant. 4296 if (!T->hasUnsignedIntegerRepresentation() 4297 || E->isValueDependent() || E->isIntegerConstantExpr(S.Context)) 4298 return AnalyzeImpConvsInComparison(S, E); 4299 4300 Expr *LHS = E->getLHS()->IgnoreParenImpCasts(); 4301 Expr *RHS = E->getRHS()->IgnoreParenImpCasts(); 4302 4303 // Check to see if one of the (unmodified) operands is of different 4304 // signedness. 4305 Expr *signedOperand, *unsignedOperand; 4306 if (LHS->getType()->hasSignedIntegerRepresentation()) { 4307 assert(!RHS->getType()->hasSignedIntegerRepresentation() && 4308 "unsigned comparison between two signed integer expressions?"); 4309 signedOperand = LHS; 4310 unsignedOperand = RHS; 4311 } else if (RHS->getType()->hasSignedIntegerRepresentation()) { 4312 signedOperand = RHS; 4313 unsignedOperand = LHS; 4314 } else { 4315 CheckTrivialUnsignedComparison(S, E); 4316 return AnalyzeImpConvsInComparison(S, E); 4317 } 4318 4319 // Otherwise, calculate the effective range of the signed operand. 4320 IntRange signedRange = GetExprRange(S.Context, signedOperand); 4321 4322 // Go ahead and analyze implicit conversions in the operands. Note 4323 // that we skip the implicit conversions on both sides. 4324 AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc()); 4325 AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc()); 4326 4327 // If the signed range is non-negative, -Wsign-compare won't fire, 4328 // but we should still check for comparisons which are always true 4329 // or false. 4330 if (signedRange.NonNegative) 4331 return CheckTrivialUnsignedComparison(S, E); 4332 4333 // For (in)equality comparisons, if the unsigned operand is a 4334 // constant which cannot collide with a overflowed signed operand, 4335 // then reinterpreting the signed operand as unsigned will not 4336 // change the result of the comparison. 4337 if (E->isEqualityOp()) { 4338 unsigned comparisonWidth = S.Context.getIntWidth(T); 4339 IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand); 4340 4341 // We should never be unable to prove that the unsigned operand is 4342 // non-negative. 4343 assert(unsignedRange.NonNegative && "unsigned range includes negative?"); 4344 4345 if (unsignedRange.Width < comparisonWidth) 4346 return; 4347 } 4348 4349 S.DiagRuntimeBehavior(E->getOperatorLoc(), E, 4350 S.PDiag(diag::warn_mixed_sign_comparison) 4351 << LHS->getType() << RHS->getType() 4352 << LHS->getSourceRange() << RHS->getSourceRange()); 4353} 4354 4355/// Analyzes an attempt to assign the given value to a bitfield. 4356/// 4357/// Returns true if there was something fishy about the attempt. 4358static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init, 4359 SourceLocation InitLoc) { 4360 assert(Bitfield->isBitField()); 4361 if (Bitfield->isInvalidDecl()) 4362 return false; 4363 4364 // White-list bool bitfields. 4365 if (Bitfield->getType()->isBooleanType()) 4366 return false; 4367 4368 // Ignore value- or type-dependent expressions. 4369 if (Bitfield->getBitWidth()->isValueDependent() || 4370 Bitfield->getBitWidth()->isTypeDependent() || 4371 Init->isValueDependent() || 4372 Init->isTypeDependent()) 4373 return false; 4374 4375 Expr *OriginalInit = Init->IgnoreParenImpCasts(); 4376 4377 llvm::APSInt Value; 4378 if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects)) 4379 return false; 4380 4381 unsigned OriginalWidth = Value.getBitWidth(); 4382 unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context); 4383 4384 if (OriginalWidth <= FieldWidth) 4385 return false; 4386 4387 // Compute the value which the bitfield will contain. 4388 llvm::APSInt TruncatedValue = Value.trunc(FieldWidth); 4389 TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType()); 4390 4391 // Check whether the stored value is equal to the original value. 4392 TruncatedValue = TruncatedValue.extend(OriginalWidth); 4393 if (llvm::APSInt::isSameValue(Value, TruncatedValue)) 4394 return false; 4395 4396 // Special-case bitfields of width 1: booleans are naturally 0/1, and 4397 // therefore don't strictly fit into a signed bitfield of width 1. 4398 if (FieldWidth == 1 && Value == 1) 4399 return false; 4400 4401 std::string PrettyValue = Value.toString(10); 4402 std::string PrettyTrunc = TruncatedValue.toString(10); 4403 4404 S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant) 4405 << PrettyValue << PrettyTrunc << OriginalInit->getType() 4406 << Init->getSourceRange(); 4407 4408 return true; 4409} 4410 4411/// Analyze the given simple or compound assignment for warning-worthy 4412/// operations. 4413static void AnalyzeAssignment(Sema &S, BinaryOperator *E) { 4414 // Just recurse on the LHS. 4415 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 4416 4417 // We want to recurse on the RHS as normal unless we're assigning to 4418 // a bitfield. 4419 if (FieldDecl *Bitfield = E->getLHS()->getBitField()) { 4420 if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(), 4421 E->getOperatorLoc())) { 4422 // Recurse, ignoring any implicit conversions on the RHS. 4423 return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(), 4424 E->getOperatorLoc()); 4425 } 4426 } 4427 4428 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 4429} 4430 4431/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 4432static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T, 4433 SourceLocation CContext, unsigned diag, 4434 bool pruneControlFlow = false) { 4435 if (pruneControlFlow) { 4436 S.DiagRuntimeBehavior(E->getExprLoc(), E, 4437 S.PDiag(diag) 4438 << SourceType << T << E->getSourceRange() 4439 << SourceRange(CContext)); 4440 return; 4441 } 4442 S.Diag(E->getExprLoc(), diag) 4443 << SourceType << T << E->getSourceRange() << SourceRange(CContext); 4444} 4445 4446/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 4447static void DiagnoseImpCast(Sema &S, Expr *E, QualType T, 4448 SourceLocation CContext, unsigned diag, 4449 bool pruneControlFlow = false) { 4450 DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow); 4451} 4452 4453/// Diagnose an implicit cast from a literal expression. Does not warn when the 4454/// cast wouldn't lose information. 4455void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T, 4456 SourceLocation CContext) { 4457 // Try to convert the literal exactly to an integer. If we can, don't warn. 4458 bool isExact = false; 4459 const llvm::APFloat &Value = FL->getValue(); 4460 llvm::APSInt IntegerValue(S.Context.getIntWidth(T), 4461 T->hasUnsignedIntegerRepresentation()); 4462 if (Value.convertToInteger(IntegerValue, 4463 llvm::APFloat::rmTowardZero, &isExact) 4464 == llvm::APFloat::opOK && isExact) 4465 return; 4466 4467 SmallString<16> PrettySourceValue; 4468 Value.toString(PrettySourceValue); 4469 SmallString<16> PrettyTargetValue; 4470 if (T->isSpecificBuiltinType(BuiltinType::Bool)) 4471 PrettyTargetValue = IntegerValue == 0 ? "false" : "true"; 4472 else 4473 IntegerValue.toString(PrettyTargetValue); 4474 4475 S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer) 4476 << FL->getType() << T.getUnqualifiedType() << PrettySourceValue 4477 << PrettyTargetValue << FL->getSourceRange() << SourceRange(CContext); 4478} 4479 4480std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) { 4481 if (!Range.Width) return "0"; 4482 4483 llvm::APSInt ValueInRange = Value; 4484 ValueInRange.setIsSigned(!Range.NonNegative); 4485 ValueInRange = ValueInRange.trunc(Range.Width); 4486 return ValueInRange.toString(10); 4487} 4488 4489static bool IsImplicitBoolFloatConversion(Sema &S, Expr *Ex, bool ToBool) { 4490 if (!isa<ImplicitCastExpr>(Ex)) 4491 return false; 4492 4493 Expr *InnerE = Ex->IgnoreParenImpCasts(); 4494 const Type *Target = S.Context.getCanonicalType(Ex->getType()).getTypePtr(); 4495 const Type *Source = 4496 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 4497 if (Target->isDependentType()) 4498 return false; 4499 4500 const BuiltinType *FloatCandidateBT = 4501 dyn_cast<BuiltinType>(ToBool ? Source : Target); 4502 const Type *BoolCandidateType = ToBool ? Target : Source; 4503 4504 return (BoolCandidateType->isSpecificBuiltinType(BuiltinType::Bool) && 4505 FloatCandidateBT && (FloatCandidateBT->isFloatingPoint())); 4506} 4507 4508void CheckImplicitArgumentConversions(Sema &S, CallExpr *TheCall, 4509 SourceLocation CC) { 4510 unsigned NumArgs = TheCall->getNumArgs(); 4511 for (unsigned i = 0; i < NumArgs; ++i) { 4512 Expr *CurrA = TheCall->getArg(i); 4513 if (!IsImplicitBoolFloatConversion(S, CurrA, true)) 4514 continue; 4515 4516 bool IsSwapped = ((i > 0) && 4517 IsImplicitBoolFloatConversion(S, TheCall->getArg(i - 1), false)); 4518 IsSwapped |= ((i < (NumArgs - 1)) && 4519 IsImplicitBoolFloatConversion(S, TheCall->getArg(i + 1), false)); 4520 if (IsSwapped) { 4521 // Warn on this floating-point to bool conversion. 4522 DiagnoseImpCast(S, CurrA->IgnoreParenImpCasts(), 4523 CurrA->getType(), CC, 4524 diag::warn_impcast_floating_point_to_bool); 4525 } 4526 } 4527} 4528 4529void CheckImplicitConversion(Sema &S, Expr *E, QualType T, 4530 SourceLocation CC, bool *ICContext = 0) { 4531 if (E->isTypeDependent() || E->isValueDependent()) return; 4532 4533 const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr(); 4534 const Type *Target = S.Context.getCanonicalType(T).getTypePtr(); 4535 if (Source == Target) return; 4536 if (Target->isDependentType()) return; 4537 4538 // If the conversion context location is invalid don't complain. We also 4539 // don't want to emit a warning if the issue occurs from the expansion of 4540 // a system macro. The problem is that 'getSpellingLoc()' is slow, so we 4541 // delay this check as long as possible. Once we detect we are in that 4542 // scenario, we just return. 4543 if (CC.isInvalid()) 4544 return; 4545 4546 // Diagnose implicit casts to bool. 4547 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) { 4548 if (isa<StringLiteral>(E)) 4549 // Warn on string literal to bool. Checks for string literals in logical 4550 // expressions, for instances, assert(0 && "error here"), is prevented 4551 // by a check in AnalyzeImplicitConversions(). 4552 return DiagnoseImpCast(S, E, T, CC, 4553 diag::warn_impcast_string_literal_to_bool); 4554 if (Source->isFunctionType()) { 4555 // Warn on function to bool. Checks free functions and static member 4556 // functions. Weakly imported functions are excluded from the check, 4557 // since it's common to test their value to check whether the linker 4558 // found a definition for them. 4559 ValueDecl *D = 0; 4560 if (DeclRefExpr* R = dyn_cast<DeclRefExpr>(E)) { 4561 D = R->getDecl(); 4562 } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) { 4563 D = M->getMemberDecl(); 4564 } 4565 4566 if (D && !D->isWeak()) { 4567 if (FunctionDecl* F = dyn_cast<FunctionDecl>(D)) { 4568 S.Diag(E->getExprLoc(), diag::warn_impcast_function_to_bool) 4569 << F << E->getSourceRange() << SourceRange(CC); 4570 S.Diag(E->getExprLoc(), diag::note_function_to_bool_silence) 4571 << FixItHint::CreateInsertion(E->getExprLoc(), "&"); 4572 QualType ReturnType; 4573 UnresolvedSet<4> NonTemplateOverloads; 4574 S.isExprCallable(*E, ReturnType, NonTemplateOverloads); 4575 if (!ReturnType.isNull() 4576 && ReturnType->isSpecificBuiltinType(BuiltinType::Bool)) 4577 S.Diag(E->getExprLoc(), diag::note_function_to_bool_call) 4578 << FixItHint::CreateInsertion( 4579 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()), "()"); 4580 return; 4581 } 4582 } 4583 } 4584 } 4585 4586 // Strip vector types. 4587 if (isa<VectorType>(Source)) { 4588 if (!isa<VectorType>(Target)) { 4589 if (S.SourceMgr.isInSystemMacro(CC)) 4590 return; 4591 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar); 4592 } 4593 4594 // If the vector cast is cast between two vectors of the same size, it is 4595 // a bitcast, not a conversion. 4596 if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target)) 4597 return; 4598 4599 Source = cast<VectorType>(Source)->getElementType().getTypePtr(); 4600 Target = cast<VectorType>(Target)->getElementType().getTypePtr(); 4601 } 4602 4603 // Strip complex types. 4604 if (isa<ComplexType>(Source)) { 4605 if (!isa<ComplexType>(Target)) { 4606 if (S.SourceMgr.isInSystemMacro(CC)) 4607 return; 4608 4609 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar); 4610 } 4611 4612 Source = cast<ComplexType>(Source)->getElementType().getTypePtr(); 4613 Target = cast<ComplexType>(Target)->getElementType().getTypePtr(); 4614 } 4615 4616 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source); 4617 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target); 4618 4619 // If the source is floating point... 4620 if (SourceBT && SourceBT->isFloatingPoint()) { 4621 // ...and the target is floating point... 4622 if (TargetBT && TargetBT->isFloatingPoint()) { 4623 // ...then warn if we're dropping FP rank. 4624 4625 // Builtin FP kinds are ordered by increasing FP rank. 4626 if (SourceBT->getKind() > TargetBT->getKind()) { 4627 // Don't warn about float constants that are precisely 4628 // representable in the target type. 4629 Expr::EvalResult result; 4630 if (E->EvaluateAsRValue(result, S.Context)) { 4631 // Value might be a float, a float vector, or a float complex. 4632 if (IsSameFloatAfterCast(result.Val, 4633 S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)), 4634 S.Context.getFloatTypeSemantics(QualType(SourceBT, 0)))) 4635 return; 4636 } 4637 4638 if (S.SourceMgr.isInSystemMacro(CC)) 4639 return; 4640 4641 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision); 4642 } 4643 return; 4644 } 4645 4646 // If the target is integral, always warn. 4647 if (TargetBT && TargetBT->isInteger()) { 4648 if (S.SourceMgr.isInSystemMacro(CC)) 4649 return; 4650 4651 Expr *InnerE = E->IgnoreParenImpCasts(); 4652 // We also want to warn on, e.g., "int i = -1.234" 4653 if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE)) 4654 if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus) 4655 InnerE = UOp->getSubExpr()->IgnoreParenImpCasts(); 4656 4657 if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) { 4658 DiagnoseFloatingLiteralImpCast(S, FL, T, CC); 4659 } else { 4660 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer); 4661 } 4662 } 4663 4664 // If the target is bool, warn if expr is a function or method call. 4665 if (Target->isSpecificBuiltinType(BuiltinType::Bool) && 4666 isa<CallExpr>(E)) { 4667 // Check last argument of function call to see if it is an 4668 // implicit cast from a type matching the type the result 4669 // is being cast to. 4670 CallExpr *CEx = cast<CallExpr>(E); 4671 unsigned NumArgs = CEx->getNumArgs(); 4672 if (NumArgs > 0) { 4673 Expr *LastA = CEx->getArg(NumArgs - 1); 4674 Expr *InnerE = LastA->IgnoreParenImpCasts(); 4675 const Type *InnerType = 4676 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 4677 if (isa<ImplicitCastExpr>(LastA) && (InnerType == Target)) { 4678 // Warn on this floating-point to bool conversion 4679 DiagnoseImpCast(S, E, T, CC, 4680 diag::warn_impcast_floating_point_to_bool); 4681 } 4682 } 4683 } 4684 return; 4685 } 4686 4687 if ((E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull) 4688 == Expr::NPCK_GNUNull) && !Target->isAnyPointerType() 4689 && !Target->isBlockPointerType() && !Target->isMemberPointerType()) { 4690 SourceLocation Loc = E->getSourceRange().getBegin(); 4691 if (Loc.isMacroID()) 4692 Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first; 4693 if (!Loc.isMacroID() || CC.isMacroID()) 4694 S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer) 4695 << T << clang::SourceRange(CC) 4696 << FixItHint::CreateReplacement(Loc, S.getFixItZeroLiteralForType(T)); 4697 } 4698 4699 if (!Source->isIntegerType() || !Target->isIntegerType()) 4700 return; 4701 4702 // TODO: remove this early return once the false positives for constant->bool 4703 // in templates, macros, etc, are reduced or removed. 4704 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) 4705 return; 4706 4707 IntRange SourceRange = GetExprRange(S.Context, E); 4708 IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target); 4709 4710 if (SourceRange.Width > TargetRange.Width) { 4711 // If the source is a constant, use a default-on diagnostic. 4712 // TODO: this should happen for bitfield stores, too. 4713 llvm::APSInt Value(32); 4714 if (E->isIntegerConstantExpr(Value, S.Context)) { 4715 if (S.SourceMgr.isInSystemMacro(CC)) 4716 return; 4717 4718 std::string PrettySourceValue = Value.toString(10); 4719 std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange); 4720 4721 S.DiagRuntimeBehavior(E->getExprLoc(), E, 4722 S.PDiag(diag::warn_impcast_integer_precision_constant) 4723 << PrettySourceValue << PrettyTargetValue 4724 << E->getType() << T << E->getSourceRange() 4725 << clang::SourceRange(CC)); 4726 return; 4727 } 4728 4729 // People want to build with -Wshorten-64-to-32 and not -Wconversion. 4730 if (S.SourceMgr.isInSystemMacro(CC)) 4731 return; 4732 4733 if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64) 4734 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32, 4735 /* pruneControlFlow */ true); 4736 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision); 4737 } 4738 4739 if ((TargetRange.NonNegative && !SourceRange.NonNegative) || 4740 (!TargetRange.NonNegative && SourceRange.NonNegative && 4741 SourceRange.Width == TargetRange.Width)) { 4742 4743 if (S.SourceMgr.isInSystemMacro(CC)) 4744 return; 4745 4746 unsigned DiagID = diag::warn_impcast_integer_sign; 4747 4748 // Traditionally, gcc has warned about this under -Wsign-compare. 4749 // We also want to warn about it in -Wconversion. 4750 // So if -Wconversion is off, use a completely identical diagnostic 4751 // in the sign-compare group. 4752 // The conditional-checking code will 4753 if (ICContext) { 4754 DiagID = diag::warn_impcast_integer_sign_conditional; 4755 *ICContext = true; 4756 } 4757 4758 return DiagnoseImpCast(S, E, T, CC, DiagID); 4759 } 4760 4761 // Diagnose conversions between different enumeration types. 4762 // In C, we pretend that the type of an EnumConstantDecl is its enumeration 4763 // type, to give us better diagnostics. 4764 QualType SourceType = E->getType(); 4765 if (!S.getLangOpts().CPlusPlus) { 4766 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 4767 if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) { 4768 EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext()); 4769 SourceType = S.Context.getTypeDeclType(Enum); 4770 Source = S.Context.getCanonicalType(SourceType).getTypePtr(); 4771 } 4772 } 4773 4774 if (const EnumType *SourceEnum = Source->getAs<EnumType>()) 4775 if (const EnumType *TargetEnum = Target->getAs<EnumType>()) 4776 if ((SourceEnum->getDecl()->getIdentifier() || 4777 SourceEnum->getDecl()->getTypedefNameForAnonDecl()) && 4778 (TargetEnum->getDecl()->getIdentifier() || 4779 TargetEnum->getDecl()->getTypedefNameForAnonDecl()) && 4780 SourceEnum != TargetEnum) { 4781 if (S.SourceMgr.isInSystemMacro(CC)) 4782 return; 4783 4784 return DiagnoseImpCast(S, E, SourceType, T, CC, 4785 diag::warn_impcast_different_enum_types); 4786 } 4787 4788 return; 4789} 4790 4791void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 4792 SourceLocation CC, QualType T); 4793 4794void CheckConditionalOperand(Sema &S, Expr *E, QualType T, 4795 SourceLocation CC, bool &ICContext) { 4796 E = E->IgnoreParenImpCasts(); 4797 4798 if (isa<ConditionalOperator>(E)) 4799 return CheckConditionalOperator(S, cast<ConditionalOperator>(E), CC, T); 4800 4801 AnalyzeImplicitConversions(S, E, CC); 4802 if (E->getType() != T) 4803 return CheckImplicitConversion(S, E, T, CC, &ICContext); 4804 return; 4805} 4806 4807void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 4808 SourceLocation CC, QualType T) { 4809 AnalyzeImplicitConversions(S, E->getCond(), CC); 4810 4811 bool Suspicious = false; 4812 CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious); 4813 CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious); 4814 4815 // If -Wconversion would have warned about either of the candidates 4816 // for a signedness conversion to the context type... 4817 if (!Suspicious) return; 4818 4819 // ...but it's currently ignored... 4820 if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional, 4821 CC)) 4822 return; 4823 4824 // ...then check whether it would have warned about either of the 4825 // candidates for a signedness conversion to the condition type. 4826 if (E->getType() == T) return; 4827 4828 Suspicious = false; 4829 CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(), 4830 E->getType(), CC, &Suspicious); 4831 if (!Suspicious) 4832 CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(), 4833 E->getType(), CC, &Suspicious); 4834} 4835 4836/// AnalyzeImplicitConversions - Find and report any interesting 4837/// implicit conversions in the given expression. There are a couple 4838/// of competing diagnostics here, -Wconversion and -Wsign-compare. 4839void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) { 4840 QualType T = OrigE->getType(); 4841 Expr *E = OrigE->IgnoreParenImpCasts(); 4842 4843 if (E->isTypeDependent() || E->isValueDependent()) 4844 return; 4845 4846 // For conditional operators, we analyze the arguments as if they 4847 // were being fed directly into the output. 4848 if (isa<ConditionalOperator>(E)) { 4849 ConditionalOperator *CO = cast<ConditionalOperator>(E); 4850 CheckConditionalOperator(S, CO, CC, T); 4851 return; 4852 } 4853 4854 // Check implicit argument conversions for function calls. 4855 if (CallExpr *Call = dyn_cast<CallExpr>(E)) 4856 CheckImplicitArgumentConversions(S, Call, CC); 4857 4858 // Go ahead and check any implicit conversions we might have skipped. 4859 // The non-canonical typecheck is just an optimization; 4860 // CheckImplicitConversion will filter out dead implicit conversions. 4861 if (E->getType() != T) 4862 CheckImplicitConversion(S, E, T, CC); 4863 4864 // Now continue drilling into this expression. 4865 4866 // Skip past explicit casts. 4867 if (isa<ExplicitCastExpr>(E)) { 4868 E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts(); 4869 return AnalyzeImplicitConversions(S, E, CC); 4870 } 4871 4872 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 4873 // Do a somewhat different check with comparison operators. 4874 if (BO->isComparisonOp()) 4875 return AnalyzeComparison(S, BO); 4876 4877 // And with simple assignments. 4878 if (BO->getOpcode() == BO_Assign) 4879 return AnalyzeAssignment(S, BO); 4880 } 4881 4882 // These break the otherwise-useful invariant below. Fortunately, 4883 // we don't really need to recurse into them, because any internal 4884 // expressions should have been analyzed already when they were 4885 // built into statements. 4886 if (isa<StmtExpr>(E)) return; 4887 4888 // Don't descend into unevaluated contexts. 4889 if (isa<UnaryExprOrTypeTraitExpr>(E)) return; 4890 4891 // Now just recurse over the expression's children. 4892 CC = E->getExprLoc(); 4893 BinaryOperator *BO = dyn_cast<BinaryOperator>(E); 4894 bool IsLogicalOperator = BO && BO->isLogicalOp(); 4895 for (Stmt::child_range I = E->children(); I; ++I) { 4896 Expr *ChildExpr = dyn_cast_or_null<Expr>(*I); 4897 if (!ChildExpr) 4898 continue; 4899 4900 if (IsLogicalOperator && 4901 isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts())) 4902 // Ignore checking string literals that are in logical operators. 4903 continue; 4904 AnalyzeImplicitConversions(S, ChildExpr, CC); 4905 } 4906} 4907 4908} // end anonymous namespace 4909 4910/// Diagnoses "dangerous" implicit conversions within the given 4911/// expression (which is a full expression). Implements -Wconversion 4912/// and -Wsign-compare. 4913/// 4914/// \param CC the "context" location of the implicit conversion, i.e. 4915/// the most location of the syntactic entity requiring the implicit 4916/// conversion 4917void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) { 4918 // Don't diagnose in unevaluated contexts. 4919 if (isUnevaluatedContext()) 4920 return; 4921 4922 // Don't diagnose for value- or type-dependent expressions. 4923 if (E->isTypeDependent() || E->isValueDependent()) 4924 return; 4925 4926 // Check for array bounds violations in cases where the check isn't triggered 4927 // elsewhere for other Expr types (like BinaryOperators), e.g. when an 4928 // ArraySubscriptExpr is on the RHS of a variable initialization. 4929 CheckArrayAccess(E); 4930 4931 // This is not the right CC for (e.g.) a variable initialization. 4932 AnalyzeImplicitConversions(*this, E, CC); 4933} 4934 4935void Sema::CheckBitFieldInitialization(SourceLocation InitLoc, 4936 FieldDecl *BitField, 4937 Expr *Init) { 4938 (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc); 4939} 4940 4941/// CheckParmsForFunctionDef - Check that the parameters of the given 4942/// function are appropriate for the definition of a function. This 4943/// takes care of any checks that cannot be performed on the 4944/// declaration itself, e.g., that the types of each of the function 4945/// parameters are complete. 4946bool Sema::CheckParmsForFunctionDef(ParmVarDecl **P, ParmVarDecl **PEnd, 4947 bool CheckParameterNames) { 4948 bool HasInvalidParm = false; 4949 for (; P != PEnd; ++P) { 4950 ParmVarDecl *Param = *P; 4951 4952 // C99 6.7.5.3p4: the parameters in a parameter type list in a 4953 // function declarator that is part of a function definition of 4954 // that function shall not have incomplete type. 4955 // 4956 // This is also C++ [dcl.fct]p6. 4957 if (!Param->isInvalidDecl() && 4958 RequireCompleteType(Param->getLocation(), Param->getType(), 4959 diag::err_typecheck_decl_incomplete_type)) { 4960 Param->setInvalidDecl(); 4961 HasInvalidParm = true; 4962 } 4963 4964 // C99 6.9.1p5: If the declarator includes a parameter type list, the 4965 // declaration of each parameter shall include an identifier. 4966 if (CheckParameterNames && 4967 Param->getIdentifier() == 0 && 4968 !Param->isImplicit() && 4969 !getLangOpts().CPlusPlus) 4970 Diag(Param->getLocation(), diag::err_parameter_name_omitted); 4971 4972 // C99 6.7.5.3p12: 4973 // If the function declarator is not part of a definition of that 4974 // function, parameters may have incomplete type and may use the [*] 4975 // notation in their sequences of declarator specifiers to specify 4976 // variable length array types. 4977 QualType PType = Param->getOriginalType(); 4978 if (const ArrayType *AT = Context.getAsArrayType(PType)) { 4979 if (AT->getSizeModifier() == ArrayType::Star) { 4980 // FIXME: This diagnosic should point the '[*]' if source-location 4981 // information is added for it. 4982 Diag(Param->getLocation(), diag::err_array_star_in_function_definition); 4983 } 4984 } 4985 } 4986 4987 return HasInvalidParm; 4988} 4989 4990/// CheckCastAlign - Implements -Wcast-align, which warns when a 4991/// pointer cast increases the alignment requirements. 4992void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) { 4993 // This is actually a lot of work to potentially be doing on every 4994 // cast; don't do it if we're ignoring -Wcast_align (as is the default). 4995 if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align, 4996 TRange.getBegin()) 4997 == DiagnosticsEngine::Ignored) 4998 return; 4999 5000 // Ignore dependent types. 5001 if (T->isDependentType() || Op->getType()->isDependentType()) 5002 return; 5003 5004 // Require that the destination be a pointer type. 5005 const PointerType *DestPtr = T->getAs<PointerType>(); 5006 if (!DestPtr) return; 5007 5008 // If the destination has alignment 1, we're done. 5009 QualType DestPointee = DestPtr->getPointeeType(); 5010 if (DestPointee->isIncompleteType()) return; 5011 CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee); 5012 if (DestAlign.isOne()) return; 5013 5014 // Require that the source be a pointer type. 5015 const PointerType *SrcPtr = Op->getType()->getAs<PointerType>(); 5016 if (!SrcPtr) return; 5017 QualType SrcPointee = SrcPtr->getPointeeType(); 5018 5019 // Whitelist casts from cv void*. We already implicitly 5020 // whitelisted casts to cv void*, since they have alignment 1. 5021 // Also whitelist casts involving incomplete types, which implicitly 5022 // includes 'void'. 5023 if (SrcPointee->isIncompleteType()) return; 5024 5025 CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee); 5026 if (SrcAlign >= DestAlign) return; 5027 5028 Diag(TRange.getBegin(), diag::warn_cast_align) 5029 << Op->getType() << T 5030 << static_cast<unsigned>(SrcAlign.getQuantity()) 5031 << static_cast<unsigned>(DestAlign.getQuantity()) 5032 << TRange << Op->getSourceRange(); 5033} 5034 5035static const Type* getElementType(const Expr *BaseExpr) { 5036 const Type* EltType = BaseExpr->getType().getTypePtr(); 5037 if (EltType->isAnyPointerType()) 5038 return EltType->getPointeeType().getTypePtr(); 5039 else if (EltType->isArrayType()) 5040 return EltType->getBaseElementTypeUnsafe(); 5041 return EltType; 5042} 5043 5044/// \brief Check whether this array fits the idiom of a size-one tail padded 5045/// array member of a struct. 5046/// 5047/// We avoid emitting out-of-bounds access warnings for such arrays as they are 5048/// commonly used to emulate flexible arrays in C89 code. 5049static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size, 5050 const NamedDecl *ND) { 5051 if (Size != 1 || !ND) return false; 5052 5053 const FieldDecl *FD = dyn_cast<FieldDecl>(ND); 5054 if (!FD) return false; 5055 5056 // Don't consider sizes resulting from macro expansions or template argument 5057 // substitution to form C89 tail-padded arrays. 5058 5059 TypeSourceInfo *TInfo = FD->getTypeSourceInfo(); 5060 while (TInfo) { 5061 TypeLoc TL = TInfo->getTypeLoc(); 5062 // Look through typedefs. 5063 const TypedefTypeLoc *TTL = dyn_cast<TypedefTypeLoc>(&TL); 5064 if (TTL) { 5065 const TypedefNameDecl *TDL = TTL->getTypedefNameDecl(); 5066 TInfo = TDL->getTypeSourceInfo(); 5067 continue; 5068 } 5069 ConstantArrayTypeLoc CTL = cast<ConstantArrayTypeLoc>(TL); 5070 const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr()); 5071 if (!SizeExpr || SizeExpr->getExprLoc().isMacroID()) 5072 return false; 5073 break; 5074 } 5075 5076 const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext()); 5077 if (!RD) return false; 5078 if (RD->isUnion()) return false; 5079 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) { 5080 if (!CRD->isStandardLayout()) return false; 5081 } 5082 5083 // See if this is the last field decl in the record. 5084 const Decl *D = FD; 5085 while ((D = D->getNextDeclInContext())) 5086 if (isa<FieldDecl>(D)) 5087 return false; 5088 return true; 5089} 5090 5091void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr, 5092 const ArraySubscriptExpr *ASE, 5093 bool AllowOnePastEnd, bool IndexNegated) { 5094 IndexExpr = IndexExpr->IgnoreParenImpCasts(); 5095 if (IndexExpr->isValueDependent()) 5096 return; 5097 5098 const Type *EffectiveType = getElementType(BaseExpr); 5099 BaseExpr = BaseExpr->IgnoreParenCasts(); 5100 const ConstantArrayType *ArrayTy = 5101 Context.getAsConstantArrayType(BaseExpr->getType()); 5102 if (!ArrayTy) 5103 return; 5104 5105 llvm::APSInt index; 5106 if (!IndexExpr->EvaluateAsInt(index, Context)) 5107 return; 5108 if (IndexNegated) 5109 index = -index; 5110 5111 const NamedDecl *ND = NULL; 5112 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 5113 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 5114 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 5115 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 5116 5117 if (index.isUnsigned() || !index.isNegative()) { 5118 llvm::APInt size = ArrayTy->getSize(); 5119 if (!size.isStrictlyPositive()) 5120 return; 5121 5122 const Type* BaseType = getElementType(BaseExpr); 5123 if (BaseType != EffectiveType) { 5124 // Make sure we're comparing apples to apples when comparing index to size 5125 uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType); 5126 uint64_t array_typesize = Context.getTypeSize(BaseType); 5127 // Handle ptrarith_typesize being zero, such as when casting to void* 5128 if (!ptrarith_typesize) ptrarith_typesize = 1; 5129 if (ptrarith_typesize != array_typesize) { 5130 // There's a cast to a different size type involved 5131 uint64_t ratio = array_typesize / ptrarith_typesize; 5132 // TODO: Be smarter about handling cases where array_typesize is not a 5133 // multiple of ptrarith_typesize 5134 if (ptrarith_typesize * ratio == array_typesize) 5135 size *= llvm::APInt(size.getBitWidth(), ratio); 5136 } 5137 } 5138 5139 if (size.getBitWidth() > index.getBitWidth()) 5140 index = index.zext(size.getBitWidth()); 5141 else if (size.getBitWidth() < index.getBitWidth()) 5142 size = size.zext(index.getBitWidth()); 5143 5144 // For array subscripting the index must be less than size, but for pointer 5145 // arithmetic also allow the index (offset) to be equal to size since 5146 // computing the next address after the end of the array is legal and 5147 // commonly done e.g. in C++ iterators and range-based for loops. 5148 if (AllowOnePastEnd ? index.ule(size) : index.ult(size)) 5149 return; 5150 5151 // Also don't warn for arrays of size 1 which are members of some 5152 // structure. These are often used to approximate flexible arrays in C89 5153 // code. 5154 if (IsTailPaddedMemberArray(*this, size, ND)) 5155 return; 5156 5157 // Suppress the warning if the subscript expression (as identified by the 5158 // ']' location) and the index expression are both from macro expansions 5159 // within a system header. 5160 if (ASE) { 5161 SourceLocation RBracketLoc = SourceMgr.getSpellingLoc( 5162 ASE->getRBracketLoc()); 5163 if (SourceMgr.isInSystemHeader(RBracketLoc)) { 5164 SourceLocation IndexLoc = SourceMgr.getSpellingLoc( 5165 IndexExpr->getLocStart()); 5166 if (SourceMgr.isFromSameFile(RBracketLoc, IndexLoc)) 5167 return; 5168 } 5169 } 5170 5171 unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds; 5172 if (ASE) 5173 DiagID = diag::warn_array_index_exceeds_bounds; 5174 5175 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 5176 PDiag(DiagID) << index.toString(10, true) 5177 << size.toString(10, true) 5178 << (unsigned)size.getLimitedValue(~0U) 5179 << IndexExpr->getSourceRange()); 5180 } else { 5181 unsigned DiagID = diag::warn_array_index_precedes_bounds; 5182 if (!ASE) { 5183 DiagID = diag::warn_ptr_arith_precedes_bounds; 5184 if (index.isNegative()) index = -index; 5185 } 5186 5187 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 5188 PDiag(DiagID) << index.toString(10, true) 5189 << IndexExpr->getSourceRange()); 5190 } 5191 5192 if (!ND) { 5193 // Try harder to find a NamedDecl to point at in the note. 5194 while (const ArraySubscriptExpr *ASE = 5195 dyn_cast<ArraySubscriptExpr>(BaseExpr)) 5196 BaseExpr = ASE->getBase()->IgnoreParenCasts(); 5197 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 5198 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 5199 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 5200 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 5201 } 5202 5203 if (ND) 5204 DiagRuntimeBehavior(ND->getLocStart(), BaseExpr, 5205 PDiag(diag::note_array_index_out_of_bounds) 5206 << ND->getDeclName()); 5207} 5208 5209void Sema::CheckArrayAccess(const Expr *expr) { 5210 int AllowOnePastEnd = 0; 5211 while (expr) { 5212 expr = expr->IgnoreParenImpCasts(); 5213 switch (expr->getStmtClass()) { 5214 case Stmt::ArraySubscriptExprClass: { 5215 const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr); 5216 CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE, 5217 AllowOnePastEnd > 0); 5218 return; 5219 } 5220 case Stmt::UnaryOperatorClass: { 5221 // Only unwrap the * and & unary operators 5222 const UnaryOperator *UO = cast<UnaryOperator>(expr); 5223 expr = UO->getSubExpr(); 5224 switch (UO->getOpcode()) { 5225 case UO_AddrOf: 5226 AllowOnePastEnd++; 5227 break; 5228 case UO_Deref: 5229 AllowOnePastEnd--; 5230 break; 5231 default: 5232 return; 5233 } 5234 break; 5235 } 5236 case Stmt::ConditionalOperatorClass: { 5237 const ConditionalOperator *cond = cast<ConditionalOperator>(expr); 5238 if (const Expr *lhs = cond->getLHS()) 5239 CheckArrayAccess(lhs); 5240 if (const Expr *rhs = cond->getRHS()) 5241 CheckArrayAccess(rhs); 5242 return; 5243 } 5244 default: 5245 return; 5246 } 5247 } 5248} 5249 5250//===--- CHECK: Objective-C retain cycles ----------------------------------// 5251 5252namespace { 5253 struct RetainCycleOwner { 5254 RetainCycleOwner() : Variable(0), Indirect(false) {} 5255 VarDecl *Variable; 5256 SourceRange Range; 5257 SourceLocation Loc; 5258 bool Indirect; 5259 5260 void setLocsFrom(Expr *e) { 5261 Loc = e->getExprLoc(); 5262 Range = e->getSourceRange(); 5263 } 5264 }; 5265} 5266 5267/// Consider whether capturing the given variable can possibly lead to 5268/// a retain cycle. 5269static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) { 5270 // In ARC, it's captured strongly iff the variable has __strong 5271 // lifetime. In MRR, it's captured strongly if the variable is 5272 // __block and has an appropriate type. 5273 if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 5274 return false; 5275 5276 owner.Variable = var; 5277 owner.setLocsFrom(ref); 5278 return true; 5279} 5280 5281static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) { 5282 while (true) { 5283 e = e->IgnoreParens(); 5284 if (CastExpr *cast = dyn_cast<CastExpr>(e)) { 5285 switch (cast->getCastKind()) { 5286 case CK_BitCast: 5287 case CK_LValueBitCast: 5288 case CK_LValueToRValue: 5289 case CK_ARCReclaimReturnedObject: 5290 e = cast->getSubExpr(); 5291 continue; 5292 5293 default: 5294 return false; 5295 } 5296 } 5297 5298 if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) { 5299 ObjCIvarDecl *ivar = ref->getDecl(); 5300 if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 5301 return false; 5302 5303 // Try to find a retain cycle in the base. 5304 if (!findRetainCycleOwner(S, ref->getBase(), owner)) 5305 return false; 5306 5307 if (ref->isFreeIvar()) owner.setLocsFrom(ref); 5308 owner.Indirect = true; 5309 return true; 5310 } 5311 5312 if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) { 5313 VarDecl *var = dyn_cast<VarDecl>(ref->getDecl()); 5314 if (!var) return false; 5315 return considerVariable(var, ref, owner); 5316 } 5317 5318 if (MemberExpr *member = dyn_cast<MemberExpr>(e)) { 5319 if (member->isArrow()) return false; 5320 5321 // Don't count this as an indirect ownership. 5322 e = member->getBase(); 5323 continue; 5324 } 5325 5326 if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) { 5327 // Only pay attention to pseudo-objects on property references. 5328 ObjCPropertyRefExpr *pre 5329 = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm() 5330 ->IgnoreParens()); 5331 if (!pre) return false; 5332 if (pre->isImplicitProperty()) return false; 5333 ObjCPropertyDecl *property = pre->getExplicitProperty(); 5334 if (!property->isRetaining() && 5335 !(property->getPropertyIvarDecl() && 5336 property->getPropertyIvarDecl()->getType() 5337 .getObjCLifetime() == Qualifiers::OCL_Strong)) 5338 return false; 5339 5340 owner.Indirect = true; 5341 if (pre->isSuperReceiver()) { 5342 owner.Variable = S.getCurMethodDecl()->getSelfDecl(); 5343 if (!owner.Variable) 5344 return false; 5345 owner.Loc = pre->getLocation(); 5346 owner.Range = pre->getSourceRange(); 5347 return true; 5348 } 5349 e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase()) 5350 ->getSourceExpr()); 5351 continue; 5352 } 5353 5354 // Array ivars? 5355 5356 return false; 5357 } 5358} 5359 5360namespace { 5361 struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> { 5362 FindCaptureVisitor(ASTContext &Context, VarDecl *variable) 5363 : EvaluatedExprVisitor<FindCaptureVisitor>(Context), 5364 Variable(variable), Capturer(0) {} 5365 5366 VarDecl *Variable; 5367 Expr *Capturer; 5368 5369 void VisitDeclRefExpr(DeclRefExpr *ref) { 5370 if (ref->getDecl() == Variable && !Capturer) 5371 Capturer = ref; 5372 } 5373 5374 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) { 5375 if (Capturer) return; 5376 Visit(ref->getBase()); 5377 if (Capturer && ref->isFreeIvar()) 5378 Capturer = ref; 5379 } 5380 5381 void VisitBlockExpr(BlockExpr *block) { 5382 // Look inside nested blocks 5383 if (block->getBlockDecl()->capturesVariable(Variable)) 5384 Visit(block->getBlockDecl()->getBody()); 5385 } 5386 5387 void VisitOpaqueValueExpr(OpaqueValueExpr *OVE) { 5388 if (Capturer) return; 5389 if (OVE->getSourceExpr()) 5390 Visit(OVE->getSourceExpr()); 5391 } 5392 }; 5393} 5394 5395/// Check whether the given argument is a block which captures a 5396/// variable. 5397static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) { 5398 assert(owner.Variable && owner.Loc.isValid()); 5399 5400 e = e->IgnoreParenCasts(); 5401 BlockExpr *block = dyn_cast<BlockExpr>(e); 5402 if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable)) 5403 return 0; 5404 5405 FindCaptureVisitor visitor(S.Context, owner.Variable); 5406 visitor.Visit(block->getBlockDecl()->getBody()); 5407 return visitor.Capturer; 5408} 5409 5410static void diagnoseRetainCycle(Sema &S, Expr *capturer, 5411 RetainCycleOwner &owner) { 5412 assert(capturer); 5413 assert(owner.Variable && owner.Loc.isValid()); 5414 5415 S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle) 5416 << owner.Variable << capturer->getSourceRange(); 5417 S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner) 5418 << owner.Indirect << owner.Range; 5419} 5420 5421/// Check for a keyword selector that starts with the word 'add' or 5422/// 'set'. 5423static bool isSetterLikeSelector(Selector sel) { 5424 if (sel.isUnarySelector()) return false; 5425 5426 StringRef str = sel.getNameForSlot(0); 5427 while (!str.empty() && str.front() == '_') str = str.substr(1); 5428 if (str.startswith("set")) 5429 str = str.substr(3); 5430 else if (str.startswith("add")) { 5431 // Specially whitelist 'addOperationWithBlock:'. 5432 if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock")) 5433 return false; 5434 str = str.substr(3); 5435 } 5436 else 5437 return false; 5438 5439 if (str.empty()) return true; 5440 return !islower(str.front()); 5441} 5442 5443/// Check a message send to see if it's likely to cause a retain cycle. 5444void Sema::checkRetainCycles(ObjCMessageExpr *msg) { 5445 // Only check instance methods whose selector looks like a setter. 5446 if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector())) 5447 return; 5448 5449 // Try to find a variable that the receiver is strongly owned by. 5450 RetainCycleOwner owner; 5451 if (msg->getReceiverKind() == ObjCMessageExpr::Instance) { 5452 if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner)) 5453 return; 5454 } else { 5455 assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance); 5456 owner.Variable = getCurMethodDecl()->getSelfDecl(); 5457 owner.Loc = msg->getSuperLoc(); 5458 owner.Range = msg->getSuperLoc(); 5459 } 5460 5461 // Check whether the receiver is captured by any of the arguments. 5462 for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i) 5463 if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner)) 5464 return diagnoseRetainCycle(*this, capturer, owner); 5465} 5466 5467/// Check a property assign to see if it's likely to cause a retain cycle. 5468void Sema::checkRetainCycles(Expr *receiver, Expr *argument) { 5469 RetainCycleOwner owner; 5470 if (!findRetainCycleOwner(*this, receiver, owner)) 5471 return; 5472 5473 if (Expr *capturer = findCapturingExpr(*this, argument, owner)) 5474 diagnoseRetainCycle(*this, capturer, owner); 5475} 5476 5477bool Sema::checkUnsafeAssigns(SourceLocation Loc, 5478 QualType LHS, Expr *RHS) { 5479 Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime(); 5480 if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone) 5481 return false; 5482 // strip off any implicit cast added to get to the one arc-specific 5483 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 5484 if (cast->getCastKind() == CK_ARCConsumeObject) { 5485 Diag(Loc, diag::warn_arc_retained_assign) 5486 << (LT == Qualifiers::OCL_ExplicitNone) << 1 5487 << RHS->getSourceRange(); 5488 return true; 5489 } 5490 RHS = cast->getSubExpr(); 5491 } 5492 return false; 5493} 5494 5495void Sema::checkUnsafeExprAssigns(SourceLocation Loc, 5496 Expr *LHS, Expr *RHS) { 5497 QualType LHSType; 5498 // PropertyRef on LHS type need be directly obtained from 5499 // its declaration as it has a PsuedoType. 5500 ObjCPropertyRefExpr *PRE 5501 = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens()); 5502 if (PRE && !PRE->isImplicitProperty()) { 5503 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 5504 if (PD) 5505 LHSType = PD->getType(); 5506 } 5507 5508 if (LHSType.isNull()) 5509 LHSType = LHS->getType(); 5510 if (checkUnsafeAssigns(Loc, LHSType, RHS)) 5511 return; 5512 Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime(); 5513 // FIXME. Check for other life times. 5514 if (LT != Qualifiers::OCL_None) 5515 return; 5516 5517 if (PRE) { 5518 if (PRE->isImplicitProperty()) 5519 return; 5520 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 5521 if (!PD) 5522 return; 5523 5524 unsigned Attributes = PD->getPropertyAttributes(); 5525 if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) { 5526 // when 'assign' attribute was not explicitly specified 5527 // by user, ignore it and rely on property type itself 5528 // for lifetime info. 5529 unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten(); 5530 if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) && 5531 LHSType->isObjCRetainableType()) 5532 return; 5533 5534 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 5535 if (cast->getCastKind() == CK_ARCConsumeObject) { 5536 Diag(Loc, diag::warn_arc_retained_property_assign) 5537 << RHS->getSourceRange(); 5538 return; 5539 } 5540 RHS = cast->getSubExpr(); 5541 } 5542 } 5543 else if (Attributes & ObjCPropertyDecl::OBJC_PR_weak) { 5544 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 5545 if (cast->getCastKind() == CK_ARCConsumeObject) { 5546 Diag(Loc, diag::warn_arc_retained_assign) 5547 << 0 << 0<< RHS->getSourceRange(); 5548 return; 5549 } 5550 RHS = cast->getSubExpr(); 5551 } 5552 } 5553 } 5554} 5555 5556//===--- CHECK: Empty statement body (-Wempty-body) ---------------------===// 5557 5558namespace { 5559bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr, 5560 SourceLocation StmtLoc, 5561 const NullStmt *Body) { 5562 // Do not warn if the body is a macro that expands to nothing, e.g: 5563 // 5564 // #define CALL(x) 5565 // if (condition) 5566 // CALL(0); 5567 // 5568 if (Body->hasLeadingEmptyMacro()) 5569 return false; 5570 5571 // Get line numbers of statement and body. 5572 bool StmtLineInvalid; 5573 unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc, 5574 &StmtLineInvalid); 5575 if (StmtLineInvalid) 5576 return false; 5577 5578 bool BodyLineInvalid; 5579 unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(), 5580 &BodyLineInvalid); 5581 if (BodyLineInvalid) 5582 return false; 5583 5584 // Warn if null statement and body are on the same line. 5585 if (StmtLine != BodyLine) 5586 return false; 5587 5588 return true; 5589} 5590} // Unnamed namespace 5591 5592void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc, 5593 const Stmt *Body, 5594 unsigned DiagID) { 5595 // Since this is a syntactic check, don't emit diagnostic for template 5596 // instantiations, this just adds noise. 5597 if (CurrentInstantiationScope) 5598 return; 5599 5600 // The body should be a null statement. 5601 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 5602 if (!NBody) 5603 return; 5604 5605 // Do the usual checks. 5606 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 5607 return; 5608 5609 Diag(NBody->getSemiLoc(), DiagID); 5610 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 5611} 5612 5613void Sema::DiagnoseEmptyLoopBody(const Stmt *S, 5614 const Stmt *PossibleBody) { 5615 assert(!CurrentInstantiationScope); // Ensured by caller 5616 5617 SourceLocation StmtLoc; 5618 const Stmt *Body; 5619 unsigned DiagID; 5620 if (const ForStmt *FS = dyn_cast<ForStmt>(S)) { 5621 StmtLoc = FS->getRParenLoc(); 5622 Body = FS->getBody(); 5623 DiagID = diag::warn_empty_for_body; 5624 } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) { 5625 StmtLoc = WS->getCond()->getSourceRange().getEnd(); 5626 Body = WS->getBody(); 5627 DiagID = diag::warn_empty_while_body; 5628 } else 5629 return; // Neither `for' nor `while'. 5630 5631 // The body should be a null statement. 5632 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 5633 if (!NBody) 5634 return; 5635 5636 // Skip expensive checks if diagnostic is disabled. 5637 if (Diags.getDiagnosticLevel(DiagID, NBody->getSemiLoc()) == 5638 DiagnosticsEngine::Ignored) 5639 return; 5640 5641 // Do the usual checks. 5642 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 5643 return; 5644 5645 // `for(...);' and `while(...);' are popular idioms, so in order to keep 5646 // noise level low, emit diagnostics only if for/while is followed by a 5647 // CompoundStmt, e.g.: 5648 // for (int i = 0; i < n; i++); 5649 // { 5650 // a(i); 5651 // } 5652 // or if for/while is followed by a statement with more indentation 5653 // than for/while itself: 5654 // for (int i = 0; i < n; i++); 5655 // a(i); 5656 bool ProbableTypo = isa<CompoundStmt>(PossibleBody); 5657 if (!ProbableTypo) { 5658 bool BodyColInvalid; 5659 unsigned BodyCol = SourceMgr.getPresumedColumnNumber( 5660 PossibleBody->getLocStart(), 5661 &BodyColInvalid); 5662 if (BodyColInvalid) 5663 return; 5664 5665 bool StmtColInvalid; 5666 unsigned StmtCol = SourceMgr.getPresumedColumnNumber( 5667 S->getLocStart(), 5668 &StmtColInvalid); 5669 if (StmtColInvalid) 5670 return; 5671 5672 if (BodyCol > StmtCol) 5673 ProbableTypo = true; 5674 } 5675 5676 if (ProbableTypo) { 5677 Diag(NBody->getSemiLoc(), DiagID); 5678 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 5679 } 5680} 5681 5682//===--- Layout compatibility ----------------------------------------------// 5683 5684namespace { 5685 5686bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2); 5687 5688/// \brief Check if two enumeration types are layout-compatible. 5689bool isLayoutCompatible(ASTContext &C, EnumDecl *ED1, EnumDecl *ED2) { 5690 // C++11 [dcl.enum] p8: 5691 // Two enumeration types are layout-compatible if they have the same 5692 // underlying type. 5693 return ED1->isComplete() && ED2->isComplete() && 5694 C.hasSameType(ED1->getIntegerType(), ED2->getIntegerType()); 5695} 5696 5697/// \brief Check if two fields are layout-compatible. 5698bool isLayoutCompatible(ASTContext &C, FieldDecl *Field1, FieldDecl *Field2) { 5699 if (!isLayoutCompatible(C, Field1->getType(), Field2->getType())) 5700 return false; 5701 5702 if (Field1->isBitField() != Field2->isBitField()) 5703 return false; 5704 5705 if (Field1->isBitField()) { 5706 // Make sure that the bit-fields are the same length. 5707 unsigned Bits1 = Field1->getBitWidthValue(C); 5708 unsigned Bits2 = Field2->getBitWidthValue(C); 5709 5710 if (Bits1 != Bits2) 5711 return false; 5712 } 5713 5714 return true; 5715} 5716 5717/// \brief Check if two standard-layout structs are layout-compatible. 5718/// (C++11 [class.mem] p17) 5719bool isLayoutCompatibleStruct(ASTContext &C, 5720 RecordDecl *RD1, 5721 RecordDecl *RD2) { 5722 // If both records are C++ classes, check that base classes match. 5723 if (const CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(RD1)) { 5724 // If one of records is a CXXRecordDecl we are in C++ mode, 5725 // thus the other one is a CXXRecordDecl, too. 5726 const CXXRecordDecl *D2CXX = cast<CXXRecordDecl>(RD2); 5727 // Check number of base classes. 5728 if (D1CXX->getNumBases() != D2CXX->getNumBases()) 5729 return false; 5730 5731 // Check the base classes. 5732 for (CXXRecordDecl::base_class_const_iterator 5733 Base1 = D1CXX->bases_begin(), 5734 BaseEnd1 = D1CXX->bases_end(), 5735 Base2 = D2CXX->bases_begin(); 5736 Base1 != BaseEnd1; 5737 ++Base1, ++Base2) { 5738 if (!isLayoutCompatible(C, Base1->getType(), Base2->getType())) 5739 return false; 5740 } 5741 } else if (const CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(RD2)) { 5742 // If only RD2 is a C++ class, it should have zero base classes. 5743 if (D2CXX->getNumBases() > 0) 5744 return false; 5745 } 5746 5747 // Check the fields. 5748 RecordDecl::field_iterator Field2 = RD2->field_begin(), 5749 Field2End = RD2->field_end(), 5750 Field1 = RD1->field_begin(), 5751 Field1End = RD1->field_end(); 5752 for ( ; Field1 != Field1End && Field2 != Field2End; ++Field1, ++Field2) { 5753 if (!isLayoutCompatible(C, *Field1, *Field2)) 5754 return false; 5755 } 5756 if (Field1 != Field1End || Field2 != Field2End) 5757 return false; 5758 5759 return true; 5760} 5761 5762/// \brief Check if two standard-layout unions are layout-compatible. 5763/// (C++11 [class.mem] p18) 5764bool isLayoutCompatibleUnion(ASTContext &C, 5765 RecordDecl *RD1, 5766 RecordDecl *RD2) { 5767 llvm::SmallPtrSet<FieldDecl *, 8> UnmatchedFields; 5768 for (RecordDecl::field_iterator Field2 = RD2->field_begin(), 5769 Field2End = RD2->field_end(); 5770 Field2 != Field2End; ++Field2) { 5771 UnmatchedFields.insert(*Field2); 5772 } 5773 5774 for (RecordDecl::field_iterator Field1 = RD1->field_begin(), 5775 Field1End = RD1->field_end(); 5776 Field1 != Field1End; ++Field1) { 5777 llvm::SmallPtrSet<FieldDecl *, 8>::iterator 5778 I = UnmatchedFields.begin(), 5779 E = UnmatchedFields.end(); 5780 5781 for ( ; I != E; ++I) { 5782 if (isLayoutCompatible(C, *Field1, *I)) { 5783 bool Result = UnmatchedFields.erase(*I); 5784 (void) Result; 5785 assert(Result); 5786 break; 5787 } 5788 } 5789 if (I == E) 5790 return false; 5791 } 5792 5793 return UnmatchedFields.empty(); 5794} 5795 5796bool isLayoutCompatible(ASTContext &C, RecordDecl *RD1, RecordDecl *RD2) { 5797 if (RD1->isUnion() != RD2->isUnion()) 5798 return false; 5799 5800 if (RD1->isUnion()) 5801 return isLayoutCompatibleUnion(C, RD1, RD2); 5802 else 5803 return isLayoutCompatibleStruct(C, RD1, RD2); 5804} 5805 5806/// \brief Check if two types are layout-compatible in C++11 sense. 5807bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2) { 5808 if (T1.isNull() || T2.isNull()) 5809 return false; 5810 5811 // C++11 [basic.types] p11: 5812 // If two types T1 and T2 are the same type, then T1 and T2 are 5813 // layout-compatible types. 5814 if (C.hasSameType(T1, T2)) 5815 return true; 5816 5817 T1 = T1.getCanonicalType().getUnqualifiedType(); 5818 T2 = T2.getCanonicalType().getUnqualifiedType(); 5819 5820 const Type::TypeClass TC1 = T1->getTypeClass(); 5821 const Type::TypeClass TC2 = T2->getTypeClass(); 5822 5823 if (TC1 != TC2) 5824 return false; 5825 5826 if (TC1 == Type::Enum) { 5827 return isLayoutCompatible(C, 5828 cast<EnumType>(T1)->getDecl(), 5829 cast<EnumType>(T2)->getDecl()); 5830 } else if (TC1 == Type::Record) { 5831 if (!T1->isStandardLayoutType() || !T2->isStandardLayoutType()) 5832 return false; 5833 5834 return isLayoutCompatible(C, 5835 cast<RecordType>(T1)->getDecl(), 5836 cast<RecordType>(T2)->getDecl()); 5837 } 5838 5839 return false; 5840} 5841} 5842 5843//===--- CHECK: pointer_with_type_tag attribute: datatypes should match ----// 5844 5845namespace { 5846/// \brief Given a type tag expression find the type tag itself. 5847/// 5848/// \param TypeExpr Type tag expression, as it appears in user's code. 5849/// 5850/// \param VD Declaration of an identifier that appears in a type tag. 5851/// 5852/// \param MagicValue Type tag magic value. 5853bool FindTypeTagExpr(const Expr *TypeExpr, const ASTContext &Ctx, 5854 const ValueDecl **VD, uint64_t *MagicValue) { 5855 while(true) { 5856 if (!TypeExpr) 5857 return false; 5858 5859 TypeExpr = TypeExpr->IgnoreParenImpCasts()->IgnoreParenCasts(); 5860 5861 switch (TypeExpr->getStmtClass()) { 5862 case Stmt::UnaryOperatorClass: { 5863 const UnaryOperator *UO = cast<UnaryOperator>(TypeExpr); 5864 if (UO->getOpcode() == UO_AddrOf || UO->getOpcode() == UO_Deref) { 5865 TypeExpr = UO->getSubExpr(); 5866 continue; 5867 } 5868 return false; 5869 } 5870 5871 case Stmt::DeclRefExprClass: { 5872 const DeclRefExpr *DRE = cast<DeclRefExpr>(TypeExpr); 5873 *VD = DRE->getDecl(); 5874 return true; 5875 } 5876 5877 case Stmt::IntegerLiteralClass: { 5878 const IntegerLiteral *IL = cast<IntegerLiteral>(TypeExpr); 5879 llvm::APInt MagicValueAPInt = IL->getValue(); 5880 if (MagicValueAPInt.getActiveBits() <= 64) { 5881 *MagicValue = MagicValueAPInt.getZExtValue(); 5882 return true; 5883 } else 5884 return false; 5885 } 5886 5887 case Stmt::BinaryConditionalOperatorClass: 5888 case Stmt::ConditionalOperatorClass: { 5889 const AbstractConditionalOperator *ACO = 5890 cast<AbstractConditionalOperator>(TypeExpr); 5891 bool Result; 5892 if (ACO->getCond()->EvaluateAsBooleanCondition(Result, Ctx)) { 5893 if (Result) 5894 TypeExpr = ACO->getTrueExpr(); 5895 else 5896 TypeExpr = ACO->getFalseExpr(); 5897 continue; 5898 } 5899 return false; 5900 } 5901 5902 case Stmt::BinaryOperatorClass: { 5903 const BinaryOperator *BO = cast<BinaryOperator>(TypeExpr); 5904 if (BO->getOpcode() == BO_Comma) { 5905 TypeExpr = BO->getRHS(); 5906 continue; 5907 } 5908 return false; 5909 } 5910 5911 default: 5912 return false; 5913 } 5914 } 5915} 5916 5917/// \brief Retrieve the C type corresponding to type tag TypeExpr. 5918/// 5919/// \param TypeExpr Expression that specifies a type tag. 5920/// 5921/// \param MagicValues Registered magic values. 5922/// 5923/// \param FoundWrongKind Set to true if a type tag was found, but of a wrong 5924/// kind. 5925/// 5926/// \param TypeInfo Information about the corresponding C type. 5927/// 5928/// \returns true if the corresponding C type was found. 5929bool GetMatchingCType( 5930 const IdentifierInfo *ArgumentKind, 5931 const Expr *TypeExpr, const ASTContext &Ctx, 5932 const llvm::DenseMap<Sema::TypeTagMagicValue, 5933 Sema::TypeTagData> *MagicValues, 5934 bool &FoundWrongKind, 5935 Sema::TypeTagData &TypeInfo) { 5936 FoundWrongKind = false; 5937 5938 // Variable declaration that has type_tag_for_datatype attribute. 5939 const ValueDecl *VD = NULL; 5940 5941 uint64_t MagicValue; 5942 5943 if (!FindTypeTagExpr(TypeExpr, Ctx, &VD, &MagicValue)) 5944 return false; 5945 5946 if (VD) { 5947 for (specific_attr_iterator<TypeTagForDatatypeAttr> 5948 I = VD->specific_attr_begin<TypeTagForDatatypeAttr>(), 5949 E = VD->specific_attr_end<TypeTagForDatatypeAttr>(); 5950 I != E; ++I) { 5951 if (I->getArgumentKind() != ArgumentKind) { 5952 FoundWrongKind = true; 5953 return false; 5954 } 5955 TypeInfo.Type = I->getMatchingCType(); 5956 TypeInfo.LayoutCompatible = I->getLayoutCompatible(); 5957 TypeInfo.MustBeNull = I->getMustBeNull(); 5958 return true; 5959 } 5960 return false; 5961 } 5962 5963 if (!MagicValues) 5964 return false; 5965 5966 llvm::DenseMap<Sema::TypeTagMagicValue, 5967 Sema::TypeTagData>::const_iterator I = 5968 MagicValues->find(std::make_pair(ArgumentKind, MagicValue)); 5969 if (I == MagicValues->end()) 5970 return false; 5971 5972 TypeInfo = I->second; 5973 return true; 5974} 5975} // unnamed namespace 5976 5977void Sema::RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind, 5978 uint64_t MagicValue, QualType Type, 5979 bool LayoutCompatible, 5980 bool MustBeNull) { 5981 if (!TypeTagForDatatypeMagicValues) 5982 TypeTagForDatatypeMagicValues.reset( 5983 new llvm::DenseMap<TypeTagMagicValue, TypeTagData>); 5984 5985 TypeTagMagicValue Magic(ArgumentKind, MagicValue); 5986 (*TypeTagForDatatypeMagicValues)[Magic] = 5987 TypeTagData(Type, LayoutCompatible, MustBeNull); 5988} 5989 5990namespace { 5991bool IsSameCharType(QualType T1, QualType T2) { 5992 const BuiltinType *BT1 = T1->getAs<BuiltinType>(); 5993 if (!BT1) 5994 return false; 5995 5996 const BuiltinType *BT2 = T2->getAs<BuiltinType>(); 5997 if (!BT2) 5998 return false; 5999 6000 BuiltinType::Kind T1Kind = BT1->getKind(); 6001 BuiltinType::Kind T2Kind = BT2->getKind(); 6002 6003 return (T1Kind == BuiltinType::SChar && T2Kind == BuiltinType::Char_S) || 6004 (T1Kind == BuiltinType::UChar && T2Kind == BuiltinType::Char_U) || 6005 (T1Kind == BuiltinType::Char_U && T2Kind == BuiltinType::UChar) || 6006 (T1Kind == BuiltinType::Char_S && T2Kind == BuiltinType::SChar); 6007} 6008} // unnamed namespace 6009 6010void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr, 6011 const Expr * const *ExprArgs) { 6012 const IdentifierInfo *ArgumentKind = Attr->getArgumentKind(); 6013 bool IsPointerAttr = Attr->getIsPointer(); 6014 6015 const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()]; 6016 bool FoundWrongKind; 6017 TypeTagData TypeInfo; 6018 if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context, 6019 TypeTagForDatatypeMagicValues.get(), 6020 FoundWrongKind, TypeInfo)) { 6021 if (FoundWrongKind) 6022 Diag(TypeTagExpr->getExprLoc(), 6023 diag::warn_type_tag_for_datatype_wrong_kind) 6024 << TypeTagExpr->getSourceRange(); 6025 return; 6026 } 6027 6028 const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()]; 6029 if (IsPointerAttr) { 6030 // Skip implicit cast of pointer to `void *' (as a function argument). 6031 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr)) 6032 if (ICE->getType()->isVoidPointerType()) 6033 ArgumentExpr = ICE->getSubExpr(); 6034 } 6035 QualType ArgumentType = ArgumentExpr->getType(); 6036 6037 // Passing a `void*' pointer shouldn't trigger a warning. 6038 if (IsPointerAttr && ArgumentType->isVoidPointerType()) 6039 return; 6040 6041 if (TypeInfo.MustBeNull) { 6042 // Type tag with matching void type requires a null pointer. 6043 if (!ArgumentExpr->isNullPointerConstant(Context, 6044 Expr::NPC_ValueDependentIsNotNull)) { 6045 Diag(ArgumentExpr->getExprLoc(), 6046 diag::warn_type_safety_null_pointer_required) 6047 << ArgumentKind->getName() 6048 << ArgumentExpr->getSourceRange() 6049 << TypeTagExpr->getSourceRange(); 6050 } 6051 return; 6052 } 6053 6054 QualType RequiredType = TypeInfo.Type; 6055 if (IsPointerAttr) 6056 RequiredType = Context.getPointerType(RequiredType); 6057 6058 bool mismatch = false; 6059 if (!TypeInfo.LayoutCompatible) { 6060 mismatch = !Context.hasSameType(ArgumentType, RequiredType); 6061 6062 // C++11 [basic.fundamental] p1: 6063 // Plain char, signed char, and unsigned char are three distinct types. 6064 // 6065 // But we treat plain `char' as equivalent to `signed char' or `unsigned 6066 // char' depending on the current char signedness mode. 6067 if (mismatch) 6068 if ((IsPointerAttr && IsSameCharType(ArgumentType->getPointeeType(), 6069 RequiredType->getPointeeType())) || 6070 (!IsPointerAttr && IsSameCharType(ArgumentType, RequiredType))) 6071 mismatch = false; 6072 } else 6073 if (IsPointerAttr) 6074 mismatch = !isLayoutCompatible(Context, 6075 ArgumentType->getPointeeType(), 6076 RequiredType->getPointeeType()); 6077 else 6078 mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType); 6079 6080 if (mismatch) 6081 Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch) 6082 << ArgumentType << ArgumentKind->getName() 6083 << TypeInfo.LayoutCompatible << RequiredType 6084 << ArgumentExpr->getSourceRange() 6085 << TypeTagExpr->getSourceRange(); 6086} 6087 6088