SemaChecking.cpp revision 3fe198bf0d6118c7b080c17c3bb28d7c84e458b9
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 }; 441 442 // We can't check the value of a dependent argument. 443 if (TheCall->getArg(i)->isTypeDependent() || 444 TheCall->getArg(i)->isValueDependent()) 445 return false; 446 447 // Check that the immediate argument is actually a constant. 448 llvm::APSInt Result; 449 if (SemaBuiltinConstantArg(TheCall, i, Result)) 450 return true; 451 452 // Range check against the upper/lower values for this instruction. 453 unsigned Val = Result.getZExtValue(); 454 if (Val < l || Val > u) 455 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 456 << l << u << TheCall->getArg(i)->getSourceRange(); 457 458 return false; 459} 460 461/// Given a FunctionDecl's FormatAttr, attempts to populate the FomatStringInfo 462/// parameter with the FormatAttr's correct format_idx and firstDataArg. 463/// Returns true when the format fits the function and the FormatStringInfo has 464/// been populated. 465bool Sema::getFormatStringInfo(const FormatAttr *Format, bool IsCXXMember, 466 FormatStringInfo *FSI) { 467 FSI->HasVAListArg = Format->getFirstArg() == 0; 468 FSI->FormatIdx = Format->getFormatIdx() - 1; 469 FSI->FirstDataArg = FSI->HasVAListArg ? 0 : Format->getFirstArg() - 1; 470 471 // The way the format attribute works in GCC, the implicit this argument 472 // of member functions is counted. However, it doesn't appear in our own 473 // lists, so decrement format_idx in that case. 474 if (IsCXXMember) { 475 if(FSI->FormatIdx == 0) 476 return false; 477 --FSI->FormatIdx; 478 if (FSI->FirstDataArg != 0) 479 --FSI->FirstDataArg; 480 } 481 return true; 482} 483 484/// Handles the checks for format strings, non-POD arguments to vararg 485/// functions, and NULL arguments passed to non-NULL parameters. 486void Sema::checkCall(NamedDecl *FDecl, Expr **Args, 487 unsigned NumArgs, 488 unsigned NumProtoArgs, 489 bool IsMemberFunction, 490 SourceLocation Loc, 491 SourceRange Range, 492 VariadicCallType CallType) { 493 // FIXME: This mechanism should be abstracted to be less fragile and 494 // more efficient. For example, just map function ids to custom 495 // handlers. 496 497 // Printf and scanf checking. 498 bool HandledFormatString = false; 499 for (specific_attr_iterator<FormatAttr> 500 I = FDecl->specific_attr_begin<FormatAttr>(), 501 E = FDecl->specific_attr_end<FormatAttr>(); I != E ; ++I) 502 if (CheckFormatArguments(*I, Args, NumArgs, IsMemberFunction, CallType, 503 Loc, Range)) 504 HandledFormatString = true; 505 506 // Refuse POD arguments that weren't caught by the format string 507 // checks above. 508 if (!HandledFormatString && CallType != VariadicDoesNotApply) 509 for (unsigned ArgIdx = NumProtoArgs; ArgIdx < NumArgs; ++ArgIdx) 510 variadicArgumentPODCheck(Args[ArgIdx], CallType); 511 512 for (specific_attr_iterator<NonNullAttr> 513 I = FDecl->specific_attr_begin<NonNullAttr>(), 514 E = FDecl->specific_attr_end<NonNullAttr>(); I != E; ++I) 515 CheckNonNullArguments(*I, Args, Loc); 516 517 // Type safety checking. 518 for (specific_attr_iterator<ArgumentWithTypeTagAttr> 519 i = FDecl->specific_attr_begin<ArgumentWithTypeTagAttr>(), 520 e = FDecl->specific_attr_end<ArgumentWithTypeTagAttr>(); i != e; ++i) { 521 CheckArgumentWithTypeTag(*i, Args); 522 } 523} 524 525/// CheckConstructorCall - Check a constructor call for correctness and safety 526/// properties not enforced by the C type system. 527void Sema::CheckConstructorCall(FunctionDecl *FDecl, Expr **Args, 528 unsigned NumArgs, 529 const FunctionProtoType *Proto, 530 SourceLocation Loc) { 531 VariadicCallType CallType = 532 Proto->isVariadic() ? VariadicConstructor : VariadicDoesNotApply; 533 checkCall(FDecl, Args, NumArgs, Proto->getNumArgs(), 534 /*IsMemberFunction=*/true, Loc, SourceRange(), CallType); 535} 536 537/// CheckFunctionCall - Check a direct function call for various correctness 538/// and safety properties not strictly enforced by the C type system. 539bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall, 540 const FunctionProtoType *Proto) { 541 bool IsMemberFunction = isa<CXXMemberCallExpr>(TheCall); 542 VariadicCallType CallType = getVariadicCallType(FDecl, Proto, 543 TheCall->getCallee()); 544 unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0; 545 checkCall(FDecl, TheCall->getArgs(), TheCall->getNumArgs(), NumProtoArgs, 546 IsMemberFunction, TheCall->getRParenLoc(), 547 TheCall->getCallee()->getSourceRange(), CallType); 548 549 IdentifierInfo *FnInfo = FDecl->getIdentifier(); 550 // None of the checks below are needed for functions that don't have 551 // simple names (e.g., C++ conversion functions). 552 if (!FnInfo) 553 return false; 554 555 unsigned CMId = FDecl->getMemoryFunctionKind(); 556 if (CMId == 0) 557 return false; 558 559 // Handle memory setting and copying functions. 560 if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat) 561 CheckStrlcpycatArguments(TheCall, FnInfo); 562 else if (CMId == Builtin::BIstrncat) 563 CheckStrncatArguments(TheCall, FnInfo); 564 else 565 CheckMemaccessArguments(TheCall, CMId, FnInfo); 566 567 return false; 568} 569 570bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac, 571 Expr **Args, unsigned NumArgs) { 572 VariadicCallType CallType = 573 Method->isVariadic() ? VariadicMethod : VariadicDoesNotApply; 574 575 checkCall(Method, Args, NumArgs, Method->param_size(), 576 /*IsMemberFunction=*/false, 577 lbrac, Method->getSourceRange(), CallType); 578 579 return false; 580} 581 582bool Sema::CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall, 583 const FunctionProtoType *Proto) { 584 const VarDecl *V = dyn_cast<VarDecl>(NDecl); 585 if (!V) 586 return false; 587 588 QualType Ty = V->getType(); 589 if (!Ty->isBlockPointerType()) 590 return false; 591 592 VariadicCallType CallType = 593 Proto && Proto->isVariadic() ? VariadicBlock : VariadicDoesNotApply ; 594 unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0; 595 596 checkCall(NDecl, TheCall->getArgs(), TheCall->getNumArgs(), 597 NumProtoArgs, /*IsMemberFunction=*/false, 598 TheCall->getRParenLoc(), 599 TheCall->getCallee()->getSourceRange(), CallType); 600 601 return false; 602} 603 604ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult, 605 AtomicExpr::AtomicOp Op) { 606 CallExpr *TheCall = cast<CallExpr>(TheCallResult.get()); 607 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 608 609 // All these operations take one of the following forms: 610 enum { 611 // C __c11_atomic_init(A *, C) 612 Init, 613 // C __c11_atomic_load(A *, int) 614 Load, 615 // void __atomic_load(A *, CP, int) 616 Copy, 617 // C __c11_atomic_add(A *, M, int) 618 Arithmetic, 619 // C __atomic_exchange_n(A *, CP, int) 620 Xchg, 621 // void __atomic_exchange(A *, C *, CP, int) 622 GNUXchg, 623 // bool __c11_atomic_compare_exchange_strong(A *, C *, CP, int, int) 624 C11CmpXchg, 625 // bool __atomic_compare_exchange(A *, C *, CP, bool, int, int) 626 GNUCmpXchg 627 } Form = Init; 628 const unsigned NumArgs[] = { 2, 2, 3, 3, 3, 4, 5, 6 }; 629 const unsigned NumVals[] = { 1, 0, 1, 1, 1, 2, 2, 3 }; 630 // where: 631 // C is an appropriate type, 632 // A is volatile _Atomic(C) for __c11 builtins and is C for GNU builtins, 633 // CP is C for __c11 builtins and GNU _n builtins and is C * otherwise, 634 // M is C if C is an integer, and ptrdiff_t if C is a pointer, and 635 // the int parameters are for orderings. 636 637 assert(AtomicExpr::AO__c11_atomic_init == 0 && 638 AtomicExpr::AO__c11_atomic_fetch_xor + 1 == AtomicExpr::AO__atomic_load 639 && "need to update code for modified C11 atomics"); 640 bool IsC11 = Op >= AtomicExpr::AO__c11_atomic_init && 641 Op <= AtomicExpr::AO__c11_atomic_fetch_xor; 642 bool IsN = Op == AtomicExpr::AO__atomic_load_n || 643 Op == AtomicExpr::AO__atomic_store_n || 644 Op == AtomicExpr::AO__atomic_exchange_n || 645 Op == AtomicExpr::AO__atomic_compare_exchange_n; 646 bool IsAddSub = false; 647 648 switch (Op) { 649 case AtomicExpr::AO__c11_atomic_init: 650 Form = Init; 651 break; 652 653 case AtomicExpr::AO__c11_atomic_load: 654 case AtomicExpr::AO__atomic_load_n: 655 Form = Load; 656 break; 657 658 case AtomicExpr::AO__c11_atomic_store: 659 case AtomicExpr::AO__atomic_load: 660 case AtomicExpr::AO__atomic_store: 661 case AtomicExpr::AO__atomic_store_n: 662 Form = Copy; 663 break; 664 665 case AtomicExpr::AO__c11_atomic_fetch_add: 666 case AtomicExpr::AO__c11_atomic_fetch_sub: 667 case AtomicExpr::AO__atomic_fetch_add: 668 case AtomicExpr::AO__atomic_fetch_sub: 669 case AtomicExpr::AO__atomic_add_fetch: 670 case AtomicExpr::AO__atomic_sub_fetch: 671 IsAddSub = true; 672 // Fall through. 673 case AtomicExpr::AO__c11_atomic_fetch_and: 674 case AtomicExpr::AO__c11_atomic_fetch_or: 675 case AtomicExpr::AO__c11_atomic_fetch_xor: 676 case AtomicExpr::AO__atomic_fetch_and: 677 case AtomicExpr::AO__atomic_fetch_or: 678 case AtomicExpr::AO__atomic_fetch_xor: 679 case AtomicExpr::AO__atomic_fetch_nand: 680 case AtomicExpr::AO__atomic_and_fetch: 681 case AtomicExpr::AO__atomic_or_fetch: 682 case AtomicExpr::AO__atomic_xor_fetch: 683 case AtomicExpr::AO__atomic_nand_fetch: 684 Form = Arithmetic; 685 break; 686 687 case AtomicExpr::AO__c11_atomic_exchange: 688 case AtomicExpr::AO__atomic_exchange_n: 689 Form = Xchg; 690 break; 691 692 case AtomicExpr::AO__atomic_exchange: 693 Form = GNUXchg; 694 break; 695 696 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 697 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 698 Form = C11CmpXchg; 699 break; 700 701 case AtomicExpr::AO__atomic_compare_exchange: 702 case AtomicExpr::AO__atomic_compare_exchange_n: 703 Form = GNUCmpXchg; 704 break; 705 } 706 707 // Check we have the right number of arguments. 708 if (TheCall->getNumArgs() < NumArgs[Form]) { 709 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 710 << 0 << NumArgs[Form] << TheCall->getNumArgs() 711 << TheCall->getCallee()->getSourceRange(); 712 return ExprError(); 713 } else if (TheCall->getNumArgs() > NumArgs[Form]) { 714 Diag(TheCall->getArg(NumArgs[Form])->getLocStart(), 715 diag::err_typecheck_call_too_many_args) 716 << 0 << NumArgs[Form] << TheCall->getNumArgs() 717 << TheCall->getCallee()->getSourceRange(); 718 return ExprError(); 719 } 720 721 // Inspect the first argument of the atomic operation. 722 Expr *Ptr = TheCall->getArg(0); 723 Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get(); 724 const PointerType *pointerType = Ptr->getType()->getAs<PointerType>(); 725 if (!pointerType) { 726 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 727 << Ptr->getType() << Ptr->getSourceRange(); 728 return ExprError(); 729 } 730 731 // For a __c11 builtin, this should be a pointer to an _Atomic type. 732 QualType AtomTy = pointerType->getPointeeType(); // 'A' 733 QualType ValType = AtomTy; // 'C' 734 if (IsC11) { 735 if (!AtomTy->isAtomicType()) { 736 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic) 737 << Ptr->getType() << Ptr->getSourceRange(); 738 return ExprError(); 739 } 740 ValType = AtomTy->getAs<AtomicType>()->getValueType(); 741 } 742 743 // For an arithmetic operation, the implied arithmetic must be well-formed. 744 if (Form == Arithmetic) { 745 // gcc does not enforce these rules for GNU atomics, but we do so for sanity. 746 if (IsAddSub && !ValType->isIntegerType() && !ValType->isPointerType()) { 747 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 748 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 749 return ExprError(); 750 } 751 if (!IsAddSub && !ValType->isIntegerType()) { 752 Diag(DRE->getLocStart(), diag::err_atomic_op_bitwise_needs_atomic_int) 753 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 754 return ExprError(); 755 } 756 } else if (IsN && !ValType->isIntegerType() && !ValType->isPointerType()) { 757 // For __atomic_*_n operations, the value type must be a scalar integral or 758 // pointer type which is 1, 2, 4, 8 or 16 bytes in length. 759 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 760 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 761 return ExprError(); 762 } 763 764 if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context)) { 765 // For GNU atomics, require a trivially-copyable type. This is not part of 766 // the GNU atomics specification, but we enforce it for sanity. 767 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_trivial_copy) 768 << Ptr->getType() << Ptr->getSourceRange(); 769 return ExprError(); 770 } 771 772 // FIXME: For any builtin other than a load, the ValType must not be 773 // const-qualified. 774 775 switch (ValType.getObjCLifetime()) { 776 case Qualifiers::OCL_None: 777 case Qualifiers::OCL_ExplicitNone: 778 // okay 779 break; 780 781 case Qualifiers::OCL_Weak: 782 case Qualifiers::OCL_Strong: 783 case Qualifiers::OCL_Autoreleasing: 784 // FIXME: Can this happen? By this point, ValType should be known 785 // to be trivially copyable. 786 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 787 << ValType << Ptr->getSourceRange(); 788 return ExprError(); 789 } 790 791 QualType ResultType = ValType; 792 if (Form == Copy || Form == GNUXchg || Form == Init) 793 ResultType = Context.VoidTy; 794 else if (Form == C11CmpXchg || Form == GNUCmpXchg) 795 ResultType = Context.BoolTy; 796 797 // The type of a parameter passed 'by value'. In the GNU atomics, such 798 // arguments are actually passed as pointers. 799 QualType ByValType = ValType; // 'CP' 800 if (!IsC11 && !IsN) 801 ByValType = Ptr->getType(); 802 803 // The first argument --- the pointer --- has a fixed type; we 804 // deduce the types of the rest of the arguments accordingly. Walk 805 // the remaining arguments, converting them to the deduced value type. 806 for (unsigned i = 1; i != NumArgs[Form]; ++i) { 807 QualType Ty; 808 if (i < NumVals[Form] + 1) { 809 switch (i) { 810 case 1: 811 // The second argument is the non-atomic operand. For arithmetic, this 812 // is always passed by value, and for a compare_exchange it is always 813 // passed by address. For the rest, GNU uses by-address and C11 uses 814 // by-value. 815 assert(Form != Load); 816 if (Form == Init || (Form == Arithmetic && ValType->isIntegerType())) 817 Ty = ValType; 818 else if (Form == Copy || Form == Xchg) 819 Ty = ByValType; 820 else if (Form == Arithmetic) 821 Ty = Context.getPointerDiffType(); 822 else 823 Ty = Context.getPointerType(ValType.getUnqualifiedType()); 824 break; 825 case 2: 826 // The third argument to compare_exchange / GNU exchange is a 827 // (pointer to a) desired value. 828 Ty = ByValType; 829 break; 830 case 3: 831 // The fourth argument to GNU compare_exchange is a 'weak' flag. 832 Ty = Context.BoolTy; 833 break; 834 } 835 } else { 836 // The order(s) are always converted to int. 837 Ty = Context.IntTy; 838 } 839 840 InitializedEntity Entity = 841 InitializedEntity::InitializeParameter(Context, Ty, false); 842 ExprResult Arg = TheCall->getArg(i); 843 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 844 if (Arg.isInvalid()) 845 return true; 846 TheCall->setArg(i, Arg.get()); 847 } 848 849 // Permute the arguments into a 'consistent' order. 850 SmallVector<Expr*, 5> SubExprs; 851 SubExprs.push_back(Ptr); 852 switch (Form) { 853 case Init: 854 // Note, AtomicExpr::getVal1() has a special case for this atomic. 855 SubExprs.push_back(TheCall->getArg(1)); // Val1 856 break; 857 case Load: 858 SubExprs.push_back(TheCall->getArg(1)); // Order 859 break; 860 case Copy: 861 case Arithmetic: 862 case Xchg: 863 SubExprs.push_back(TheCall->getArg(2)); // Order 864 SubExprs.push_back(TheCall->getArg(1)); // Val1 865 break; 866 case GNUXchg: 867 // Note, AtomicExpr::getVal2() has a special case for this atomic. 868 SubExprs.push_back(TheCall->getArg(3)); // Order 869 SubExprs.push_back(TheCall->getArg(1)); // Val1 870 SubExprs.push_back(TheCall->getArg(2)); // Val2 871 break; 872 case C11CmpXchg: 873 SubExprs.push_back(TheCall->getArg(3)); // Order 874 SubExprs.push_back(TheCall->getArg(1)); // Val1 875 SubExprs.push_back(TheCall->getArg(4)); // OrderFail 876 SubExprs.push_back(TheCall->getArg(2)); // Val2 877 break; 878 case GNUCmpXchg: 879 SubExprs.push_back(TheCall->getArg(4)); // Order 880 SubExprs.push_back(TheCall->getArg(1)); // Val1 881 SubExprs.push_back(TheCall->getArg(5)); // OrderFail 882 SubExprs.push_back(TheCall->getArg(2)); // Val2 883 SubExprs.push_back(TheCall->getArg(3)); // Weak 884 break; 885 } 886 887 return Owned(new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(), 888 SubExprs.data(), SubExprs.size(), 889 ResultType, Op, 890 TheCall->getRParenLoc())); 891} 892 893 894/// checkBuiltinArgument - Given a call to a builtin function, perform 895/// normal type-checking on the given argument, updating the call in 896/// place. This is useful when a builtin function requires custom 897/// type-checking for some of its arguments but not necessarily all of 898/// them. 899/// 900/// Returns true on error. 901static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) { 902 FunctionDecl *Fn = E->getDirectCallee(); 903 assert(Fn && "builtin call without direct callee!"); 904 905 ParmVarDecl *Param = Fn->getParamDecl(ArgIndex); 906 InitializedEntity Entity = 907 InitializedEntity::InitializeParameter(S.Context, Param); 908 909 ExprResult Arg = E->getArg(0); 910 Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg); 911 if (Arg.isInvalid()) 912 return true; 913 914 E->setArg(ArgIndex, Arg.take()); 915 return false; 916} 917 918/// SemaBuiltinAtomicOverloaded - We have a call to a function like 919/// __sync_fetch_and_add, which is an overloaded function based on the pointer 920/// type of its first argument. The main ActOnCallExpr routines have already 921/// promoted the types of arguments because all of these calls are prototyped as 922/// void(...). 923/// 924/// This function goes through and does final semantic checking for these 925/// builtins, 926ExprResult 927Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) { 928 CallExpr *TheCall = (CallExpr *)TheCallResult.get(); 929 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 930 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 931 932 // Ensure that we have at least one argument to do type inference from. 933 if (TheCall->getNumArgs() < 1) { 934 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 935 << 0 << 1 << TheCall->getNumArgs() 936 << TheCall->getCallee()->getSourceRange(); 937 return ExprError(); 938 } 939 940 // Inspect the first argument of the atomic builtin. This should always be 941 // a pointer type, whose element is an integral scalar or pointer type. 942 // Because it is a pointer type, we don't have to worry about any implicit 943 // casts here. 944 // FIXME: We don't allow floating point scalars as input. 945 Expr *FirstArg = TheCall->getArg(0); 946 ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg); 947 if (FirstArgResult.isInvalid()) 948 return ExprError(); 949 FirstArg = FirstArgResult.take(); 950 TheCall->setArg(0, FirstArg); 951 952 const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>(); 953 if (!pointerType) { 954 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 955 << FirstArg->getType() << FirstArg->getSourceRange(); 956 return ExprError(); 957 } 958 959 QualType ValType = pointerType->getPointeeType(); 960 if (!ValType->isIntegerType() && !ValType->isAnyPointerType() && 961 !ValType->isBlockPointerType()) { 962 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr) 963 << FirstArg->getType() << FirstArg->getSourceRange(); 964 return ExprError(); 965 } 966 967 switch (ValType.getObjCLifetime()) { 968 case Qualifiers::OCL_None: 969 case Qualifiers::OCL_ExplicitNone: 970 // okay 971 break; 972 973 case Qualifiers::OCL_Weak: 974 case Qualifiers::OCL_Strong: 975 case Qualifiers::OCL_Autoreleasing: 976 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 977 << ValType << FirstArg->getSourceRange(); 978 return ExprError(); 979 } 980 981 // Strip any qualifiers off ValType. 982 ValType = ValType.getUnqualifiedType(); 983 984 // The majority of builtins return a value, but a few have special return 985 // types, so allow them to override appropriately below. 986 QualType ResultType = ValType; 987 988 // We need to figure out which concrete builtin this maps onto. For example, 989 // __sync_fetch_and_add with a 2 byte object turns into 990 // __sync_fetch_and_add_2. 991#define BUILTIN_ROW(x) \ 992 { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \ 993 Builtin::BI##x##_8, Builtin::BI##x##_16 } 994 995 static const unsigned BuiltinIndices[][5] = { 996 BUILTIN_ROW(__sync_fetch_and_add), 997 BUILTIN_ROW(__sync_fetch_and_sub), 998 BUILTIN_ROW(__sync_fetch_and_or), 999 BUILTIN_ROW(__sync_fetch_and_and), 1000 BUILTIN_ROW(__sync_fetch_and_xor), 1001 1002 BUILTIN_ROW(__sync_add_and_fetch), 1003 BUILTIN_ROW(__sync_sub_and_fetch), 1004 BUILTIN_ROW(__sync_and_and_fetch), 1005 BUILTIN_ROW(__sync_or_and_fetch), 1006 BUILTIN_ROW(__sync_xor_and_fetch), 1007 1008 BUILTIN_ROW(__sync_val_compare_and_swap), 1009 BUILTIN_ROW(__sync_bool_compare_and_swap), 1010 BUILTIN_ROW(__sync_lock_test_and_set), 1011 BUILTIN_ROW(__sync_lock_release), 1012 BUILTIN_ROW(__sync_swap) 1013 }; 1014#undef BUILTIN_ROW 1015 1016 // Determine the index of the size. 1017 unsigned SizeIndex; 1018 switch (Context.getTypeSizeInChars(ValType).getQuantity()) { 1019 case 1: SizeIndex = 0; break; 1020 case 2: SizeIndex = 1; break; 1021 case 4: SizeIndex = 2; break; 1022 case 8: SizeIndex = 3; break; 1023 case 16: SizeIndex = 4; break; 1024 default: 1025 Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size) 1026 << FirstArg->getType() << FirstArg->getSourceRange(); 1027 return ExprError(); 1028 } 1029 1030 // Each of these builtins has one pointer argument, followed by some number of 1031 // values (0, 1 or 2) followed by a potentially empty varags list of stuff 1032 // that we ignore. Find out which row of BuiltinIndices to read from as well 1033 // as the number of fixed args. 1034 unsigned BuiltinID = FDecl->getBuiltinID(); 1035 unsigned BuiltinIndex, NumFixed = 1; 1036 switch (BuiltinID) { 1037 default: llvm_unreachable("Unknown overloaded atomic builtin!"); 1038 case Builtin::BI__sync_fetch_and_add: 1039 case Builtin::BI__sync_fetch_and_add_1: 1040 case Builtin::BI__sync_fetch_and_add_2: 1041 case Builtin::BI__sync_fetch_and_add_4: 1042 case Builtin::BI__sync_fetch_and_add_8: 1043 case Builtin::BI__sync_fetch_and_add_16: 1044 BuiltinIndex = 0; 1045 break; 1046 1047 case Builtin::BI__sync_fetch_and_sub: 1048 case Builtin::BI__sync_fetch_and_sub_1: 1049 case Builtin::BI__sync_fetch_and_sub_2: 1050 case Builtin::BI__sync_fetch_and_sub_4: 1051 case Builtin::BI__sync_fetch_and_sub_8: 1052 case Builtin::BI__sync_fetch_and_sub_16: 1053 BuiltinIndex = 1; 1054 break; 1055 1056 case Builtin::BI__sync_fetch_and_or: 1057 case Builtin::BI__sync_fetch_and_or_1: 1058 case Builtin::BI__sync_fetch_and_or_2: 1059 case Builtin::BI__sync_fetch_and_or_4: 1060 case Builtin::BI__sync_fetch_and_or_8: 1061 case Builtin::BI__sync_fetch_and_or_16: 1062 BuiltinIndex = 2; 1063 break; 1064 1065 case Builtin::BI__sync_fetch_and_and: 1066 case Builtin::BI__sync_fetch_and_and_1: 1067 case Builtin::BI__sync_fetch_and_and_2: 1068 case Builtin::BI__sync_fetch_and_and_4: 1069 case Builtin::BI__sync_fetch_and_and_8: 1070 case Builtin::BI__sync_fetch_and_and_16: 1071 BuiltinIndex = 3; 1072 break; 1073 1074 case Builtin::BI__sync_fetch_and_xor: 1075 case Builtin::BI__sync_fetch_and_xor_1: 1076 case Builtin::BI__sync_fetch_and_xor_2: 1077 case Builtin::BI__sync_fetch_and_xor_4: 1078 case Builtin::BI__sync_fetch_and_xor_8: 1079 case Builtin::BI__sync_fetch_and_xor_16: 1080 BuiltinIndex = 4; 1081 break; 1082 1083 case Builtin::BI__sync_add_and_fetch: 1084 case Builtin::BI__sync_add_and_fetch_1: 1085 case Builtin::BI__sync_add_and_fetch_2: 1086 case Builtin::BI__sync_add_and_fetch_4: 1087 case Builtin::BI__sync_add_and_fetch_8: 1088 case Builtin::BI__sync_add_and_fetch_16: 1089 BuiltinIndex = 5; 1090 break; 1091 1092 case Builtin::BI__sync_sub_and_fetch: 1093 case Builtin::BI__sync_sub_and_fetch_1: 1094 case Builtin::BI__sync_sub_and_fetch_2: 1095 case Builtin::BI__sync_sub_and_fetch_4: 1096 case Builtin::BI__sync_sub_and_fetch_8: 1097 case Builtin::BI__sync_sub_and_fetch_16: 1098 BuiltinIndex = 6; 1099 break; 1100 1101 case Builtin::BI__sync_and_and_fetch: 1102 case Builtin::BI__sync_and_and_fetch_1: 1103 case Builtin::BI__sync_and_and_fetch_2: 1104 case Builtin::BI__sync_and_and_fetch_4: 1105 case Builtin::BI__sync_and_and_fetch_8: 1106 case Builtin::BI__sync_and_and_fetch_16: 1107 BuiltinIndex = 7; 1108 break; 1109 1110 case Builtin::BI__sync_or_and_fetch: 1111 case Builtin::BI__sync_or_and_fetch_1: 1112 case Builtin::BI__sync_or_and_fetch_2: 1113 case Builtin::BI__sync_or_and_fetch_4: 1114 case Builtin::BI__sync_or_and_fetch_8: 1115 case Builtin::BI__sync_or_and_fetch_16: 1116 BuiltinIndex = 8; 1117 break; 1118 1119 case Builtin::BI__sync_xor_and_fetch: 1120 case Builtin::BI__sync_xor_and_fetch_1: 1121 case Builtin::BI__sync_xor_and_fetch_2: 1122 case Builtin::BI__sync_xor_and_fetch_4: 1123 case Builtin::BI__sync_xor_and_fetch_8: 1124 case Builtin::BI__sync_xor_and_fetch_16: 1125 BuiltinIndex = 9; 1126 break; 1127 1128 case Builtin::BI__sync_val_compare_and_swap: 1129 case Builtin::BI__sync_val_compare_and_swap_1: 1130 case Builtin::BI__sync_val_compare_and_swap_2: 1131 case Builtin::BI__sync_val_compare_and_swap_4: 1132 case Builtin::BI__sync_val_compare_and_swap_8: 1133 case Builtin::BI__sync_val_compare_and_swap_16: 1134 BuiltinIndex = 10; 1135 NumFixed = 2; 1136 break; 1137 1138 case Builtin::BI__sync_bool_compare_and_swap: 1139 case Builtin::BI__sync_bool_compare_and_swap_1: 1140 case Builtin::BI__sync_bool_compare_and_swap_2: 1141 case Builtin::BI__sync_bool_compare_and_swap_4: 1142 case Builtin::BI__sync_bool_compare_and_swap_8: 1143 case Builtin::BI__sync_bool_compare_and_swap_16: 1144 BuiltinIndex = 11; 1145 NumFixed = 2; 1146 ResultType = Context.BoolTy; 1147 break; 1148 1149 case Builtin::BI__sync_lock_test_and_set: 1150 case Builtin::BI__sync_lock_test_and_set_1: 1151 case Builtin::BI__sync_lock_test_and_set_2: 1152 case Builtin::BI__sync_lock_test_and_set_4: 1153 case Builtin::BI__sync_lock_test_and_set_8: 1154 case Builtin::BI__sync_lock_test_and_set_16: 1155 BuiltinIndex = 12; 1156 break; 1157 1158 case Builtin::BI__sync_lock_release: 1159 case Builtin::BI__sync_lock_release_1: 1160 case Builtin::BI__sync_lock_release_2: 1161 case Builtin::BI__sync_lock_release_4: 1162 case Builtin::BI__sync_lock_release_8: 1163 case Builtin::BI__sync_lock_release_16: 1164 BuiltinIndex = 13; 1165 NumFixed = 0; 1166 ResultType = Context.VoidTy; 1167 break; 1168 1169 case Builtin::BI__sync_swap: 1170 case Builtin::BI__sync_swap_1: 1171 case Builtin::BI__sync_swap_2: 1172 case Builtin::BI__sync_swap_4: 1173 case Builtin::BI__sync_swap_8: 1174 case Builtin::BI__sync_swap_16: 1175 BuiltinIndex = 14; 1176 break; 1177 } 1178 1179 // Now that we know how many fixed arguments we expect, first check that we 1180 // have at least that many. 1181 if (TheCall->getNumArgs() < 1+NumFixed) { 1182 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 1183 << 0 << 1+NumFixed << TheCall->getNumArgs() 1184 << TheCall->getCallee()->getSourceRange(); 1185 return ExprError(); 1186 } 1187 1188 // Get the decl for the concrete builtin from this, we can tell what the 1189 // concrete integer type we should convert to is. 1190 unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex]; 1191 const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID); 1192 IdentifierInfo *NewBuiltinII = PP.getIdentifierInfo(NewBuiltinName); 1193 FunctionDecl *NewBuiltinDecl = 1194 cast<FunctionDecl>(LazilyCreateBuiltin(NewBuiltinII, NewBuiltinID, 1195 TUScope, false, DRE->getLocStart())); 1196 1197 // The first argument --- the pointer --- has a fixed type; we 1198 // deduce the types of the rest of the arguments accordingly. Walk 1199 // the remaining arguments, converting them to the deduced value type. 1200 for (unsigned i = 0; i != NumFixed; ++i) { 1201 ExprResult Arg = TheCall->getArg(i+1); 1202 1203 // GCC does an implicit conversion to the pointer or integer ValType. This 1204 // can fail in some cases (1i -> int**), check for this error case now. 1205 // Initialize the argument. 1206 InitializedEntity Entity = InitializedEntity::InitializeParameter(Context, 1207 ValType, /*consume*/ false); 1208 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 1209 if (Arg.isInvalid()) 1210 return ExprError(); 1211 1212 // Okay, we have something that *can* be converted to the right type. Check 1213 // to see if there is a potentially weird extension going on here. This can 1214 // happen when you do an atomic operation on something like an char* and 1215 // pass in 42. The 42 gets converted to char. This is even more strange 1216 // for things like 45.123 -> char, etc. 1217 // FIXME: Do this check. 1218 TheCall->setArg(i+1, Arg.take()); 1219 } 1220 1221 ASTContext& Context = this->getASTContext(); 1222 1223 // Create a new DeclRefExpr to refer to the new decl. 1224 DeclRefExpr* NewDRE = DeclRefExpr::Create( 1225 Context, 1226 DRE->getQualifierLoc(), 1227 SourceLocation(), 1228 NewBuiltinDecl, 1229 /*enclosing*/ false, 1230 DRE->getLocation(), 1231 NewBuiltinDecl->getType(), 1232 DRE->getValueKind()); 1233 1234 // Set the callee in the CallExpr. 1235 // FIXME: This leaks the original parens and implicit casts. 1236 ExprResult PromotedCall = UsualUnaryConversions(NewDRE); 1237 if (PromotedCall.isInvalid()) 1238 return ExprError(); 1239 TheCall->setCallee(PromotedCall.take()); 1240 1241 // Change the result type of the call to match the original value type. This 1242 // is arbitrary, but the codegen for these builtins ins design to handle it 1243 // gracefully. 1244 TheCall->setType(ResultType); 1245 1246 return TheCallResult; 1247} 1248 1249/// CheckObjCString - Checks that the argument to the builtin 1250/// CFString constructor is correct 1251/// Note: It might also make sense to do the UTF-16 conversion here (would 1252/// simplify the backend). 1253bool Sema::CheckObjCString(Expr *Arg) { 1254 Arg = Arg->IgnoreParenCasts(); 1255 StringLiteral *Literal = dyn_cast<StringLiteral>(Arg); 1256 1257 if (!Literal || !Literal->isAscii()) { 1258 Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant) 1259 << Arg->getSourceRange(); 1260 return true; 1261 } 1262 1263 if (Literal->containsNonAsciiOrNull()) { 1264 StringRef String = Literal->getString(); 1265 unsigned NumBytes = String.size(); 1266 SmallVector<UTF16, 128> ToBuf(NumBytes); 1267 const UTF8 *FromPtr = (UTF8 *)String.data(); 1268 UTF16 *ToPtr = &ToBuf[0]; 1269 1270 ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, 1271 &ToPtr, ToPtr + NumBytes, 1272 strictConversion); 1273 // Check for conversion failure. 1274 if (Result != conversionOK) 1275 Diag(Arg->getLocStart(), 1276 diag::warn_cfstring_truncated) << Arg->getSourceRange(); 1277 } 1278 return false; 1279} 1280 1281/// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity. 1282/// Emit an error and return true on failure, return false on success. 1283bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) { 1284 Expr *Fn = TheCall->getCallee(); 1285 if (TheCall->getNumArgs() > 2) { 1286 Diag(TheCall->getArg(2)->getLocStart(), 1287 diag::err_typecheck_call_too_many_args) 1288 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1289 << Fn->getSourceRange() 1290 << SourceRange(TheCall->getArg(2)->getLocStart(), 1291 (*(TheCall->arg_end()-1))->getLocEnd()); 1292 return true; 1293 } 1294 1295 if (TheCall->getNumArgs() < 2) { 1296 return Diag(TheCall->getLocEnd(), 1297 diag::err_typecheck_call_too_few_args_at_least) 1298 << 0 /*function call*/ << 2 << TheCall->getNumArgs(); 1299 } 1300 1301 // Type-check the first argument normally. 1302 if (checkBuiltinArgument(*this, TheCall, 0)) 1303 return true; 1304 1305 // Determine whether the current function is variadic or not. 1306 BlockScopeInfo *CurBlock = getCurBlock(); 1307 bool isVariadic; 1308 if (CurBlock) 1309 isVariadic = CurBlock->TheDecl->isVariadic(); 1310 else if (FunctionDecl *FD = getCurFunctionDecl()) 1311 isVariadic = FD->isVariadic(); 1312 else 1313 isVariadic = getCurMethodDecl()->isVariadic(); 1314 1315 if (!isVariadic) { 1316 Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function); 1317 return true; 1318 } 1319 1320 // Verify that the second argument to the builtin is the last argument of the 1321 // current function or method. 1322 bool SecondArgIsLastNamedArgument = false; 1323 const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts(); 1324 1325 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) { 1326 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) { 1327 // FIXME: This isn't correct for methods (results in bogus warning). 1328 // Get the last formal in the current function. 1329 const ParmVarDecl *LastArg; 1330 if (CurBlock) 1331 LastArg = *(CurBlock->TheDecl->param_end()-1); 1332 else if (FunctionDecl *FD = getCurFunctionDecl()) 1333 LastArg = *(FD->param_end()-1); 1334 else 1335 LastArg = *(getCurMethodDecl()->param_end()-1); 1336 SecondArgIsLastNamedArgument = PV == LastArg; 1337 } 1338 } 1339 1340 if (!SecondArgIsLastNamedArgument) 1341 Diag(TheCall->getArg(1)->getLocStart(), 1342 diag::warn_second_parameter_of_va_start_not_last_named_argument); 1343 return false; 1344} 1345 1346/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and 1347/// friends. This is declared to take (...), so we have to check everything. 1348bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) { 1349 if (TheCall->getNumArgs() < 2) 1350 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 1351 << 0 << 2 << TheCall->getNumArgs()/*function call*/; 1352 if (TheCall->getNumArgs() > 2) 1353 return Diag(TheCall->getArg(2)->getLocStart(), 1354 diag::err_typecheck_call_too_many_args) 1355 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1356 << SourceRange(TheCall->getArg(2)->getLocStart(), 1357 (*(TheCall->arg_end()-1))->getLocEnd()); 1358 1359 ExprResult OrigArg0 = TheCall->getArg(0); 1360 ExprResult OrigArg1 = TheCall->getArg(1); 1361 1362 // Do standard promotions between the two arguments, returning their common 1363 // type. 1364 QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false); 1365 if (OrigArg0.isInvalid() || OrigArg1.isInvalid()) 1366 return true; 1367 1368 // Make sure any conversions are pushed back into the call; this is 1369 // type safe since unordered compare builtins are declared as "_Bool 1370 // foo(...)". 1371 TheCall->setArg(0, OrigArg0.get()); 1372 TheCall->setArg(1, OrigArg1.get()); 1373 1374 if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent()) 1375 return false; 1376 1377 // If the common type isn't a real floating type, then the arguments were 1378 // invalid for this operation. 1379 if (Res.isNull() || !Res->isRealFloatingType()) 1380 return Diag(OrigArg0.get()->getLocStart(), 1381 diag::err_typecheck_call_invalid_ordered_compare) 1382 << OrigArg0.get()->getType() << OrigArg1.get()->getType() 1383 << SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd()); 1384 1385 return false; 1386} 1387 1388/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like 1389/// __builtin_isnan and friends. This is declared to take (...), so we have 1390/// to check everything. We expect the last argument to be a floating point 1391/// value. 1392bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) { 1393 if (TheCall->getNumArgs() < NumArgs) 1394 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 1395 << 0 << NumArgs << TheCall->getNumArgs()/*function call*/; 1396 if (TheCall->getNumArgs() > NumArgs) 1397 return Diag(TheCall->getArg(NumArgs)->getLocStart(), 1398 diag::err_typecheck_call_too_many_args) 1399 << 0 /*function call*/ << NumArgs << TheCall->getNumArgs() 1400 << SourceRange(TheCall->getArg(NumArgs)->getLocStart(), 1401 (*(TheCall->arg_end()-1))->getLocEnd()); 1402 1403 Expr *OrigArg = TheCall->getArg(NumArgs-1); 1404 1405 if (OrigArg->isTypeDependent()) 1406 return false; 1407 1408 // This operation requires a non-_Complex floating-point number. 1409 if (!OrigArg->getType()->isRealFloatingType()) 1410 return Diag(OrigArg->getLocStart(), 1411 diag::err_typecheck_call_invalid_unary_fp) 1412 << OrigArg->getType() << OrigArg->getSourceRange(); 1413 1414 // If this is an implicit conversion from float -> double, remove it. 1415 if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) { 1416 Expr *CastArg = Cast->getSubExpr(); 1417 if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) { 1418 assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) && 1419 "promotion from float to double is the only expected cast here"); 1420 Cast->setSubExpr(0); 1421 TheCall->setArg(NumArgs-1, CastArg); 1422 } 1423 } 1424 1425 return false; 1426} 1427 1428/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector. 1429// This is declared to take (...), so we have to check everything. 1430ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) { 1431 if (TheCall->getNumArgs() < 2) 1432 return ExprError(Diag(TheCall->getLocEnd(), 1433 diag::err_typecheck_call_too_few_args_at_least) 1434 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1435 << TheCall->getSourceRange()); 1436 1437 // Determine which of the following types of shufflevector we're checking: 1438 // 1) unary, vector mask: (lhs, mask) 1439 // 2) binary, vector mask: (lhs, rhs, mask) 1440 // 3) binary, scalar mask: (lhs, rhs, index, ..., index) 1441 QualType resType = TheCall->getArg(0)->getType(); 1442 unsigned numElements = 0; 1443 1444 if (!TheCall->getArg(0)->isTypeDependent() && 1445 !TheCall->getArg(1)->isTypeDependent()) { 1446 QualType LHSType = TheCall->getArg(0)->getType(); 1447 QualType RHSType = TheCall->getArg(1)->getType(); 1448 1449 if (!LHSType->isVectorType() || !RHSType->isVectorType()) { 1450 Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector) 1451 << SourceRange(TheCall->getArg(0)->getLocStart(), 1452 TheCall->getArg(1)->getLocEnd()); 1453 return ExprError(); 1454 } 1455 1456 numElements = LHSType->getAs<VectorType>()->getNumElements(); 1457 unsigned numResElements = TheCall->getNumArgs() - 2; 1458 1459 // Check to see if we have a call with 2 vector arguments, the unary shuffle 1460 // with mask. If so, verify that RHS is an integer vector type with the 1461 // same number of elts as lhs. 1462 if (TheCall->getNumArgs() == 2) { 1463 if (!RHSType->hasIntegerRepresentation() || 1464 RHSType->getAs<VectorType>()->getNumElements() != numElements) 1465 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 1466 << SourceRange(TheCall->getArg(1)->getLocStart(), 1467 TheCall->getArg(1)->getLocEnd()); 1468 numResElements = numElements; 1469 } 1470 else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) { 1471 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 1472 << SourceRange(TheCall->getArg(0)->getLocStart(), 1473 TheCall->getArg(1)->getLocEnd()); 1474 return ExprError(); 1475 } else if (numElements != numResElements) { 1476 QualType eltType = LHSType->getAs<VectorType>()->getElementType(); 1477 resType = Context.getVectorType(eltType, numResElements, 1478 VectorType::GenericVector); 1479 } 1480 } 1481 1482 for (unsigned i = 2; i < TheCall->getNumArgs(); i++) { 1483 if (TheCall->getArg(i)->isTypeDependent() || 1484 TheCall->getArg(i)->isValueDependent()) 1485 continue; 1486 1487 llvm::APSInt Result(32); 1488 if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context)) 1489 return ExprError(Diag(TheCall->getLocStart(), 1490 diag::err_shufflevector_nonconstant_argument) 1491 << TheCall->getArg(i)->getSourceRange()); 1492 1493 if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2) 1494 return ExprError(Diag(TheCall->getLocStart(), 1495 diag::err_shufflevector_argument_too_large) 1496 << TheCall->getArg(i)->getSourceRange()); 1497 } 1498 1499 SmallVector<Expr*, 32> exprs; 1500 1501 for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) { 1502 exprs.push_back(TheCall->getArg(i)); 1503 TheCall->setArg(i, 0); 1504 } 1505 1506 return Owned(new (Context) ShuffleVectorExpr(Context, exprs.begin(), 1507 exprs.size(), resType, 1508 TheCall->getCallee()->getLocStart(), 1509 TheCall->getRParenLoc())); 1510} 1511 1512/// SemaBuiltinPrefetch - Handle __builtin_prefetch. 1513// This is declared to take (const void*, ...) and can take two 1514// optional constant int args. 1515bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) { 1516 unsigned NumArgs = TheCall->getNumArgs(); 1517 1518 if (NumArgs > 3) 1519 return Diag(TheCall->getLocEnd(), 1520 diag::err_typecheck_call_too_many_args_at_most) 1521 << 0 /*function call*/ << 3 << NumArgs 1522 << TheCall->getSourceRange(); 1523 1524 // Argument 0 is checked for us and the remaining arguments must be 1525 // constant integers. 1526 for (unsigned i = 1; i != NumArgs; ++i) { 1527 Expr *Arg = TheCall->getArg(i); 1528 1529 // We can't check the value of a dependent argument. 1530 if (Arg->isTypeDependent() || Arg->isValueDependent()) 1531 continue; 1532 1533 llvm::APSInt Result; 1534 if (SemaBuiltinConstantArg(TheCall, i, Result)) 1535 return true; 1536 1537 // FIXME: gcc issues a warning and rewrites these to 0. These 1538 // seems especially odd for the third argument since the default 1539 // is 3. 1540 if (i == 1) { 1541 if (Result.getLimitedValue() > 1) 1542 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1543 << "0" << "1" << Arg->getSourceRange(); 1544 } else { 1545 if (Result.getLimitedValue() > 3) 1546 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1547 << "0" << "3" << Arg->getSourceRange(); 1548 } 1549 } 1550 1551 return false; 1552} 1553 1554/// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr 1555/// TheCall is a constant expression. 1556bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum, 1557 llvm::APSInt &Result) { 1558 Expr *Arg = TheCall->getArg(ArgNum); 1559 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 1560 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 1561 1562 if (Arg->isTypeDependent() || Arg->isValueDependent()) return false; 1563 1564 if (!Arg->isIntegerConstantExpr(Result, Context)) 1565 return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type) 1566 << FDecl->getDeclName() << Arg->getSourceRange(); 1567 1568 return false; 1569} 1570 1571/// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr, 1572/// int type). This simply type checks that type is one of the defined 1573/// constants (0-3). 1574// For compatibility check 0-3, llvm only handles 0 and 2. 1575bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) { 1576 llvm::APSInt Result; 1577 1578 // We can't check the value of a dependent argument. 1579 if (TheCall->getArg(1)->isTypeDependent() || 1580 TheCall->getArg(1)->isValueDependent()) 1581 return false; 1582 1583 // Check constant-ness first. 1584 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 1585 return true; 1586 1587 Expr *Arg = TheCall->getArg(1); 1588 if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) { 1589 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1590 << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 1591 } 1592 1593 return false; 1594} 1595 1596/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val). 1597/// This checks that val is a constant 1. 1598bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) { 1599 Expr *Arg = TheCall->getArg(1); 1600 llvm::APSInt Result; 1601 1602 // TODO: This is less than ideal. Overload this to take a value. 1603 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 1604 return true; 1605 1606 if (Result != 1) 1607 return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val) 1608 << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 1609 1610 return false; 1611} 1612 1613// Determine if an expression is a string literal or constant string. 1614// If this function returns false on the arguments to a function expecting a 1615// format string, we will usually need to emit a warning. 1616// True string literals are then checked by CheckFormatString. 1617Sema::StringLiteralCheckType 1618Sema::checkFormatStringExpr(const Expr *E, Expr **Args, 1619 unsigned NumArgs, bool HasVAListArg, 1620 unsigned format_idx, unsigned firstDataArg, 1621 FormatStringType Type, VariadicCallType CallType, 1622 bool inFunctionCall) { 1623 tryAgain: 1624 if (E->isTypeDependent() || E->isValueDependent()) 1625 return SLCT_NotALiteral; 1626 1627 E = E->IgnoreParenCasts(); 1628 1629 if (E->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull)) 1630 // Technically -Wformat-nonliteral does not warn about this case. 1631 // The behavior of printf and friends in this case is implementation 1632 // dependent. Ideally if the format string cannot be null then 1633 // it should have a 'nonnull' attribute in the function prototype. 1634 return SLCT_CheckedLiteral; 1635 1636 switch (E->getStmtClass()) { 1637 case Stmt::BinaryConditionalOperatorClass: 1638 case Stmt::ConditionalOperatorClass: { 1639 // The expression is a literal if both sub-expressions were, and it was 1640 // completely checked only if both sub-expressions were checked. 1641 const AbstractConditionalOperator *C = 1642 cast<AbstractConditionalOperator>(E); 1643 StringLiteralCheckType Left = 1644 checkFormatStringExpr(C->getTrueExpr(), Args, NumArgs, 1645 HasVAListArg, format_idx, firstDataArg, 1646 Type, CallType, inFunctionCall); 1647 if (Left == SLCT_NotALiteral) 1648 return SLCT_NotALiteral; 1649 StringLiteralCheckType Right = 1650 checkFormatStringExpr(C->getFalseExpr(), Args, NumArgs, 1651 HasVAListArg, format_idx, firstDataArg, 1652 Type, CallType, inFunctionCall); 1653 return Left < Right ? Left : Right; 1654 } 1655 1656 case Stmt::ImplicitCastExprClass: { 1657 E = cast<ImplicitCastExpr>(E)->getSubExpr(); 1658 goto tryAgain; 1659 } 1660 1661 case Stmt::OpaqueValueExprClass: 1662 if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) { 1663 E = src; 1664 goto tryAgain; 1665 } 1666 return SLCT_NotALiteral; 1667 1668 case Stmt::PredefinedExprClass: 1669 // While __func__, etc., are technically not string literals, they 1670 // cannot contain format specifiers and thus are not a security 1671 // liability. 1672 return SLCT_UncheckedLiteral; 1673 1674 case Stmt::DeclRefExprClass: { 1675 const DeclRefExpr *DR = cast<DeclRefExpr>(E); 1676 1677 // As an exception, do not flag errors for variables binding to 1678 // const string literals. 1679 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) { 1680 bool isConstant = false; 1681 QualType T = DR->getType(); 1682 1683 if (const ArrayType *AT = Context.getAsArrayType(T)) { 1684 isConstant = AT->getElementType().isConstant(Context); 1685 } else if (const PointerType *PT = T->getAs<PointerType>()) { 1686 isConstant = T.isConstant(Context) && 1687 PT->getPointeeType().isConstant(Context); 1688 } else if (T->isObjCObjectPointerType()) { 1689 // In ObjC, there is usually no "const ObjectPointer" type, 1690 // so don't check if the pointee type is constant. 1691 isConstant = T.isConstant(Context); 1692 } 1693 1694 if (isConstant) { 1695 if (const Expr *Init = VD->getAnyInitializer()) { 1696 // Look through initializers like const char c[] = { "foo" } 1697 if (const InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) { 1698 if (InitList->isStringLiteralInit()) 1699 Init = InitList->getInit(0)->IgnoreParenImpCasts(); 1700 } 1701 return checkFormatStringExpr(Init, Args, NumArgs, 1702 HasVAListArg, format_idx, 1703 firstDataArg, Type, CallType, 1704 /*inFunctionCall*/false); 1705 } 1706 } 1707 1708 // For vprintf* functions (i.e., HasVAListArg==true), we add a 1709 // special check to see if the format string is a function parameter 1710 // of the function calling the printf function. If the function 1711 // has an attribute indicating it is a printf-like function, then we 1712 // should suppress warnings concerning non-literals being used in a call 1713 // to a vprintf function. For example: 1714 // 1715 // void 1716 // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){ 1717 // va_list ap; 1718 // va_start(ap, fmt); 1719 // vprintf(fmt, ap); // Do NOT emit a warning about "fmt". 1720 // ... 1721 // 1722 if (HasVAListArg) { 1723 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(VD)) { 1724 if (const NamedDecl *ND = dyn_cast<NamedDecl>(PV->getDeclContext())) { 1725 int PVIndex = PV->getFunctionScopeIndex() + 1; 1726 for (specific_attr_iterator<FormatAttr> 1727 i = ND->specific_attr_begin<FormatAttr>(), 1728 e = ND->specific_attr_end<FormatAttr>(); i != e ; ++i) { 1729 FormatAttr *PVFormat = *i; 1730 // adjust for implicit parameter 1731 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 1732 if (MD->isInstance()) 1733 ++PVIndex; 1734 // We also check if the formats are compatible. 1735 // We can't pass a 'scanf' string to a 'printf' function. 1736 if (PVIndex == PVFormat->getFormatIdx() && 1737 Type == GetFormatStringType(PVFormat)) 1738 return SLCT_UncheckedLiteral; 1739 } 1740 } 1741 } 1742 } 1743 } 1744 1745 return SLCT_NotALiteral; 1746 } 1747 1748 case Stmt::CallExprClass: 1749 case Stmt::CXXMemberCallExprClass: { 1750 const CallExpr *CE = cast<CallExpr>(E); 1751 if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) { 1752 if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) { 1753 unsigned ArgIndex = FA->getFormatIdx(); 1754 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 1755 if (MD->isInstance()) 1756 --ArgIndex; 1757 const Expr *Arg = CE->getArg(ArgIndex - 1); 1758 1759 return checkFormatStringExpr(Arg, Args, NumArgs, 1760 HasVAListArg, format_idx, firstDataArg, 1761 Type, CallType, inFunctionCall); 1762 } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) { 1763 unsigned BuiltinID = FD->getBuiltinID(); 1764 if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString || 1765 BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) { 1766 const Expr *Arg = CE->getArg(0); 1767 return checkFormatStringExpr(Arg, Args, NumArgs, 1768 HasVAListArg, format_idx, 1769 firstDataArg, Type, CallType, 1770 inFunctionCall); 1771 } 1772 } 1773 } 1774 1775 return SLCT_NotALiteral; 1776 } 1777 case Stmt::ObjCStringLiteralClass: 1778 case Stmt::StringLiteralClass: { 1779 const StringLiteral *StrE = NULL; 1780 1781 if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E)) 1782 StrE = ObjCFExpr->getString(); 1783 else 1784 StrE = cast<StringLiteral>(E); 1785 1786 if (StrE) { 1787 CheckFormatString(StrE, E, Args, NumArgs, HasVAListArg, format_idx, 1788 firstDataArg, Type, inFunctionCall, CallType); 1789 return SLCT_CheckedLiteral; 1790 } 1791 1792 return SLCT_NotALiteral; 1793 } 1794 1795 default: 1796 return SLCT_NotALiteral; 1797 } 1798} 1799 1800void 1801Sema::CheckNonNullArguments(const NonNullAttr *NonNull, 1802 const Expr * const *ExprArgs, 1803 SourceLocation CallSiteLoc) { 1804 for (NonNullAttr::args_iterator i = NonNull->args_begin(), 1805 e = NonNull->args_end(); 1806 i != e; ++i) { 1807 const Expr *ArgExpr = ExprArgs[*i]; 1808 if (ArgExpr->isNullPointerConstant(Context, 1809 Expr::NPC_ValueDependentIsNotNull)) 1810 Diag(CallSiteLoc, diag::warn_null_arg) << ArgExpr->getSourceRange(); 1811 } 1812} 1813 1814Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) { 1815 return llvm::StringSwitch<FormatStringType>(Format->getType()) 1816 .Case("scanf", FST_Scanf) 1817 .Cases("printf", "printf0", FST_Printf) 1818 .Cases("NSString", "CFString", FST_NSString) 1819 .Case("strftime", FST_Strftime) 1820 .Case("strfmon", FST_Strfmon) 1821 .Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf) 1822 .Default(FST_Unknown); 1823} 1824 1825/// CheckFormatArguments - Check calls to printf and scanf (and similar 1826/// functions) for correct use of format strings. 1827/// Returns true if a format string has been fully checked. 1828bool Sema::CheckFormatArguments(const FormatAttr *Format, Expr **Args, 1829 unsigned NumArgs, bool IsCXXMember, 1830 VariadicCallType CallType, 1831 SourceLocation Loc, SourceRange Range) { 1832 FormatStringInfo FSI; 1833 if (getFormatStringInfo(Format, IsCXXMember, &FSI)) 1834 return CheckFormatArguments(Args, NumArgs, FSI.HasVAListArg, FSI.FormatIdx, 1835 FSI.FirstDataArg, GetFormatStringType(Format), 1836 CallType, Loc, Range); 1837 return false; 1838} 1839 1840bool Sema::CheckFormatArguments(Expr **Args, unsigned NumArgs, 1841 bool HasVAListArg, unsigned format_idx, 1842 unsigned firstDataArg, FormatStringType Type, 1843 VariadicCallType CallType, 1844 SourceLocation Loc, SourceRange Range) { 1845 // CHECK: printf/scanf-like function is called with no format string. 1846 if (format_idx >= NumArgs) { 1847 Diag(Loc, diag::warn_missing_format_string) << Range; 1848 return false; 1849 } 1850 1851 const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts(); 1852 1853 // CHECK: format string is not a string literal. 1854 // 1855 // Dynamically generated format strings are difficult to 1856 // automatically vet at compile time. Requiring that format strings 1857 // are string literals: (1) permits the checking of format strings by 1858 // the compiler and thereby (2) can practically remove the source of 1859 // many format string exploits. 1860 1861 // Format string can be either ObjC string (e.g. @"%d") or 1862 // C string (e.g. "%d") 1863 // ObjC string uses the same format specifiers as C string, so we can use 1864 // the same format string checking logic for both ObjC and C strings. 1865 StringLiteralCheckType CT = 1866 checkFormatStringExpr(OrigFormatExpr, Args, NumArgs, HasVAListArg, 1867 format_idx, firstDataArg, Type, CallType); 1868 if (CT != SLCT_NotALiteral) 1869 // Literal format string found, check done! 1870 return CT == SLCT_CheckedLiteral; 1871 1872 // Strftime is particular as it always uses a single 'time' argument, 1873 // so it is safe to pass a non-literal string. 1874 if (Type == FST_Strftime) 1875 return false; 1876 1877 // Do not emit diag when the string param is a macro expansion and the 1878 // format is either NSString or CFString. This is a hack to prevent 1879 // diag when using the NSLocalizedString and CFCopyLocalizedString macros 1880 // which are usually used in place of NS and CF string literals. 1881 if (Type == FST_NSString && 1882 SourceMgr.isInSystemMacro(Args[format_idx]->getLocStart())) 1883 return false; 1884 1885 // If there are no arguments specified, warn with -Wformat-security, otherwise 1886 // warn only with -Wformat-nonliteral. 1887 if (NumArgs == format_idx+1) 1888 Diag(Args[format_idx]->getLocStart(), 1889 diag::warn_format_nonliteral_noargs) 1890 << OrigFormatExpr->getSourceRange(); 1891 else 1892 Diag(Args[format_idx]->getLocStart(), 1893 diag::warn_format_nonliteral) 1894 << OrigFormatExpr->getSourceRange(); 1895 return false; 1896} 1897 1898namespace { 1899class CheckFormatHandler : public analyze_format_string::FormatStringHandler { 1900protected: 1901 Sema &S; 1902 const StringLiteral *FExpr; 1903 const Expr *OrigFormatExpr; 1904 const unsigned FirstDataArg; 1905 const unsigned NumDataArgs; 1906 const char *Beg; // Start of format string. 1907 const bool HasVAListArg; 1908 const Expr * const *Args; 1909 const unsigned NumArgs; 1910 unsigned FormatIdx; 1911 llvm::BitVector CoveredArgs; 1912 bool usesPositionalArgs; 1913 bool atFirstArg; 1914 bool inFunctionCall; 1915 Sema::VariadicCallType CallType; 1916public: 1917 CheckFormatHandler(Sema &s, const StringLiteral *fexpr, 1918 const Expr *origFormatExpr, unsigned firstDataArg, 1919 unsigned numDataArgs, const char *beg, bool hasVAListArg, 1920 Expr **args, unsigned numArgs, 1921 unsigned formatIdx, bool inFunctionCall, 1922 Sema::VariadicCallType callType) 1923 : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr), 1924 FirstDataArg(firstDataArg), NumDataArgs(numDataArgs), 1925 Beg(beg), HasVAListArg(hasVAListArg), 1926 Args(args), NumArgs(numArgs), FormatIdx(formatIdx), 1927 usesPositionalArgs(false), atFirstArg(true), 1928 inFunctionCall(inFunctionCall), CallType(callType) { 1929 CoveredArgs.resize(numDataArgs); 1930 CoveredArgs.reset(); 1931 } 1932 1933 void DoneProcessing(); 1934 1935 void HandleIncompleteSpecifier(const char *startSpecifier, 1936 unsigned specifierLen); 1937 1938 void HandleNonStandardLengthModifier( 1939 const analyze_format_string::LengthModifier &LM, 1940 const char *startSpecifier, unsigned specifierLen); 1941 1942 void HandleNonStandardConversionSpecifier( 1943 const analyze_format_string::ConversionSpecifier &CS, 1944 const char *startSpecifier, unsigned specifierLen); 1945 1946 void HandleNonStandardConversionSpecification( 1947 const analyze_format_string::LengthModifier &LM, 1948 const analyze_format_string::ConversionSpecifier &CS, 1949 const char *startSpecifier, unsigned specifierLen); 1950 1951 virtual void HandlePosition(const char *startPos, unsigned posLen); 1952 1953 virtual void HandleInvalidPosition(const char *startSpecifier, 1954 unsigned specifierLen, 1955 analyze_format_string::PositionContext p); 1956 1957 virtual void HandleZeroPosition(const char *startPos, unsigned posLen); 1958 1959 void HandleNullChar(const char *nullCharacter); 1960 1961 template <typename Range> 1962 static void EmitFormatDiagnostic(Sema &S, bool inFunctionCall, 1963 const Expr *ArgumentExpr, 1964 PartialDiagnostic PDiag, 1965 SourceLocation StringLoc, 1966 bool IsStringLocation, Range StringRange, 1967 FixItHint Fixit = FixItHint()); 1968 1969protected: 1970 bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc, 1971 const char *startSpec, 1972 unsigned specifierLen, 1973 const char *csStart, unsigned csLen); 1974 1975 void HandlePositionalNonpositionalArgs(SourceLocation Loc, 1976 const char *startSpec, 1977 unsigned specifierLen); 1978 1979 SourceRange getFormatStringRange(); 1980 CharSourceRange getSpecifierRange(const char *startSpecifier, 1981 unsigned specifierLen); 1982 SourceLocation getLocationOfByte(const char *x); 1983 1984 const Expr *getDataArg(unsigned i) const; 1985 1986 bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS, 1987 const analyze_format_string::ConversionSpecifier &CS, 1988 const char *startSpecifier, unsigned specifierLen, 1989 unsigned argIndex); 1990 1991 template <typename Range> 1992 void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc, 1993 bool IsStringLocation, Range StringRange, 1994 FixItHint Fixit = FixItHint()); 1995 1996 void CheckPositionalAndNonpositionalArgs( 1997 const analyze_format_string::FormatSpecifier *FS); 1998}; 1999} 2000 2001SourceRange CheckFormatHandler::getFormatStringRange() { 2002 return OrigFormatExpr->getSourceRange(); 2003} 2004 2005CharSourceRange CheckFormatHandler:: 2006getSpecifierRange(const char *startSpecifier, unsigned specifierLen) { 2007 SourceLocation Start = getLocationOfByte(startSpecifier); 2008 SourceLocation End = getLocationOfByte(startSpecifier + specifierLen - 1); 2009 2010 // Advance the end SourceLocation by one due to half-open ranges. 2011 End = End.getLocWithOffset(1); 2012 2013 return CharSourceRange::getCharRange(Start, End); 2014} 2015 2016SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) { 2017 return S.getLocationOfStringLiteralByte(FExpr, x - Beg); 2018} 2019 2020void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier, 2021 unsigned specifierLen){ 2022 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier), 2023 getLocationOfByte(startSpecifier), 2024 /*IsStringLocation*/true, 2025 getSpecifierRange(startSpecifier, specifierLen)); 2026} 2027 2028void CheckFormatHandler::HandleNonStandardLengthModifier( 2029 const analyze_format_string::LengthModifier &LM, 2030 const char *startSpecifier, unsigned specifierLen) { 2031 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) << LM.toString() 2032 << 0, 2033 getLocationOfByte(LM.getStart()), 2034 /*IsStringLocation*/true, 2035 getSpecifierRange(startSpecifier, specifierLen)); 2036} 2037 2038void CheckFormatHandler::HandleNonStandardConversionSpecifier( 2039 const analyze_format_string::ConversionSpecifier &CS, 2040 const char *startSpecifier, unsigned specifierLen) { 2041 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) << CS.toString() 2042 << 1, 2043 getLocationOfByte(CS.getStart()), 2044 /*IsStringLocation*/true, 2045 getSpecifierRange(startSpecifier, specifierLen)); 2046} 2047 2048void CheckFormatHandler::HandleNonStandardConversionSpecification( 2049 const analyze_format_string::LengthModifier &LM, 2050 const analyze_format_string::ConversionSpecifier &CS, 2051 const char *startSpecifier, unsigned specifierLen) { 2052 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_conversion_spec) 2053 << LM.toString() << CS.toString(), 2054 getLocationOfByte(LM.getStart()), 2055 /*IsStringLocation*/true, 2056 getSpecifierRange(startSpecifier, specifierLen)); 2057} 2058 2059void CheckFormatHandler::HandlePosition(const char *startPos, 2060 unsigned posLen) { 2061 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg), 2062 getLocationOfByte(startPos), 2063 /*IsStringLocation*/true, 2064 getSpecifierRange(startPos, posLen)); 2065} 2066 2067void 2068CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen, 2069 analyze_format_string::PositionContext p) { 2070 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier) 2071 << (unsigned) p, 2072 getLocationOfByte(startPos), /*IsStringLocation*/true, 2073 getSpecifierRange(startPos, posLen)); 2074} 2075 2076void CheckFormatHandler::HandleZeroPosition(const char *startPos, 2077 unsigned posLen) { 2078 EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier), 2079 getLocationOfByte(startPos), 2080 /*IsStringLocation*/true, 2081 getSpecifierRange(startPos, posLen)); 2082} 2083 2084void CheckFormatHandler::HandleNullChar(const char *nullCharacter) { 2085 if (!isa<ObjCStringLiteral>(OrigFormatExpr)) { 2086 // The presence of a null character is likely an error. 2087 EmitFormatDiagnostic( 2088 S.PDiag(diag::warn_printf_format_string_contains_null_char), 2089 getLocationOfByte(nullCharacter), /*IsStringLocation*/true, 2090 getFormatStringRange()); 2091 } 2092} 2093 2094// Note that this may return NULL if there was an error parsing or building 2095// one of the argument expressions. 2096const Expr *CheckFormatHandler::getDataArg(unsigned i) const { 2097 return Args[FirstDataArg + i]; 2098} 2099 2100void CheckFormatHandler::DoneProcessing() { 2101 // Does the number of data arguments exceed the number of 2102 // format conversions in the format string? 2103 if (!HasVAListArg) { 2104 // Find any arguments that weren't covered. 2105 CoveredArgs.flip(); 2106 signed notCoveredArg = CoveredArgs.find_first(); 2107 if (notCoveredArg >= 0) { 2108 assert((unsigned)notCoveredArg < NumDataArgs); 2109 if (const Expr *E = getDataArg((unsigned) notCoveredArg)) { 2110 SourceLocation Loc = E->getLocStart(); 2111 if (!S.getSourceManager().isInSystemMacro(Loc)) { 2112 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_data_arg_not_used), 2113 Loc, /*IsStringLocation*/false, 2114 getFormatStringRange()); 2115 } 2116 } 2117 } 2118 } 2119} 2120 2121bool 2122CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex, 2123 SourceLocation Loc, 2124 const char *startSpec, 2125 unsigned specifierLen, 2126 const char *csStart, 2127 unsigned csLen) { 2128 2129 bool keepGoing = true; 2130 if (argIndex < NumDataArgs) { 2131 // Consider the argument coverered, even though the specifier doesn't 2132 // make sense. 2133 CoveredArgs.set(argIndex); 2134 } 2135 else { 2136 // If argIndex exceeds the number of data arguments we 2137 // don't issue a warning because that is just a cascade of warnings (and 2138 // they may have intended '%%' anyway). We don't want to continue processing 2139 // the format string after this point, however, as we will like just get 2140 // gibberish when trying to match arguments. 2141 keepGoing = false; 2142 } 2143 2144 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion) 2145 << StringRef(csStart, csLen), 2146 Loc, /*IsStringLocation*/true, 2147 getSpecifierRange(startSpec, specifierLen)); 2148 2149 return keepGoing; 2150} 2151 2152void 2153CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc, 2154 const char *startSpec, 2155 unsigned specifierLen) { 2156 EmitFormatDiagnostic( 2157 S.PDiag(diag::warn_format_mix_positional_nonpositional_args), 2158 Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen)); 2159} 2160 2161bool 2162CheckFormatHandler::CheckNumArgs( 2163 const analyze_format_string::FormatSpecifier &FS, 2164 const analyze_format_string::ConversionSpecifier &CS, 2165 const char *startSpecifier, unsigned specifierLen, unsigned argIndex) { 2166 2167 if (argIndex >= NumDataArgs) { 2168 PartialDiagnostic PDiag = FS.usesPositionalArg() 2169 ? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args) 2170 << (argIndex+1) << NumDataArgs) 2171 : S.PDiag(diag::warn_printf_insufficient_data_args); 2172 EmitFormatDiagnostic( 2173 PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true, 2174 getSpecifierRange(startSpecifier, specifierLen)); 2175 return false; 2176 } 2177 return true; 2178} 2179 2180template<typename Range> 2181void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag, 2182 SourceLocation Loc, 2183 bool IsStringLocation, 2184 Range StringRange, 2185 FixItHint FixIt) { 2186 EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag, 2187 Loc, IsStringLocation, StringRange, FixIt); 2188} 2189 2190/// \brief If the format string is not within the funcion call, emit a note 2191/// so that the function call and string are in diagnostic messages. 2192/// 2193/// \param InFunctionCall if true, the format string is within the function 2194/// call and only one diagnostic message will be produced. Otherwise, an 2195/// extra note will be emitted pointing to location of the format string. 2196/// 2197/// \param ArgumentExpr the expression that is passed as the format string 2198/// argument in the function call. Used for getting locations when two 2199/// diagnostics are emitted. 2200/// 2201/// \param PDiag the callee should already have provided any strings for the 2202/// diagnostic message. This function only adds locations and fixits 2203/// to diagnostics. 2204/// 2205/// \param Loc primary location for diagnostic. If two diagnostics are 2206/// required, one will be at Loc and a new SourceLocation will be created for 2207/// the other one. 2208/// 2209/// \param IsStringLocation if true, Loc points to the format string should be 2210/// used for the note. Otherwise, Loc points to the argument list and will 2211/// be used with PDiag. 2212/// 2213/// \param StringRange some or all of the string to highlight. This is 2214/// templated so it can accept either a CharSourceRange or a SourceRange. 2215/// 2216/// \param FixIt optional fix it hint for the format string. 2217template<typename Range> 2218void CheckFormatHandler::EmitFormatDiagnostic(Sema &S, bool InFunctionCall, 2219 const Expr *ArgumentExpr, 2220 PartialDiagnostic PDiag, 2221 SourceLocation Loc, 2222 bool IsStringLocation, 2223 Range StringRange, 2224 FixItHint FixIt) { 2225 if (InFunctionCall) 2226 S.Diag(Loc, PDiag) << StringRange << FixIt; 2227 else { 2228 S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag) 2229 << ArgumentExpr->getSourceRange(); 2230 S.Diag(IsStringLocation ? Loc : StringRange.getBegin(), 2231 diag::note_format_string_defined) 2232 << StringRange << FixIt; 2233 } 2234} 2235 2236//===--- CHECK: Printf format string checking ------------------------------===// 2237 2238namespace { 2239class CheckPrintfHandler : public CheckFormatHandler { 2240 bool ObjCContext; 2241public: 2242 CheckPrintfHandler(Sema &s, const StringLiteral *fexpr, 2243 const Expr *origFormatExpr, unsigned firstDataArg, 2244 unsigned numDataArgs, bool isObjC, 2245 const char *beg, bool hasVAListArg, 2246 Expr **Args, unsigned NumArgs, 2247 unsigned formatIdx, bool inFunctionCall, 2248 Sema::VariadicCallType CallType) 2249 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 2250 numDataArgs, beg, hasVAListArg, Args, NumArgs, 2251 formatIdx, inFunctionCall, CallType), ObjCContext(isObjC) 2252 {} 2253 2254 2255 bool HandleInvalidPrintfConversionSpecifier( 2256 const analyze_printf::PrintfSpecifier &FS, 2257 const char *startSpecifier, 2258 unsigned specifierLen); 2259 2260 bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS, 2261 const char *startSpecifier, 2262 unsigned specifierLen); 2263 bool checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 2264 const char *StartSpecifier, 2265 unsigned SpecifierLen, 2266 const Expr *E); 2267 2268 bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k, 2269 const char *startSpecifier, unsigned specifierLen); 2270 void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS, 2271 const analyze_printf::OptionalAmount &Amt, 2272 unsigned type, 2273 const char *startSpecifier, unsigned specifierLen); 2274 void HandleFlag(const analyze_printf::PrintfSpecifier &FS, 2275 const analyze_printf::OptionalFlag &flag, 2276 const char *startSpecifier, unsigned specifierLen); 2277 void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS, 2278 const analyze_printf::OptionalFlag &ignoredFlag, 2279 const analyze_printf::OptionalFlag &flag, 2280 const char *startSpecifier, unsigned specifierLen); 2281 bool checkForCStrMembers(const analyze_printf::ArgType &AT, 2282 const Expr *E, const CharSourceRange &CSR); 2283 2284}; 2285} 2286 2287bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier( 2288 const analyze_printf::PrintfSpecifier &FS, 2289 const char *startSpecifier, 2290 unsigned specifierLen) { 2291 const analyze_printf::PrintfConversionSpecifier &CS = 2292 FS.getConversionSpecifier(); 2293 2294 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 2295 getLocationOfByte(CS.getStart()), 2296 startSpecifier, specifierLen, 2297 CS.getStart(), CS.getLength()); 2298} 2299 2300bool CheckPrintfHandler::HandleAmount( 2301 const analyze_format_string::OptionalAmount &Amt, 2302 unsigned k, const char *startSpecifier, 2303 unsigned specifierLen) { 2304 2305 if (Amt.hasDataArgument()) { 2306 if (!HasVAListArg) { 2307 unsigned argIndex = Amt.getArgIndex(); 2308 if (argIndex >= NumDataArgs) { 2309 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg) 2310 << k, 2311 getLocationOfByte(Amt.getStart()), 2312 /*IsStringLocation*/true, 2313 getSpecifierRange(startSpecifier, specifierLen)); 2314 // Don't do any more checking. We will just emit 2315 // spurious errors. 2316 return false; 2317 } 2318 2319 // Type check the data argument. It should be an 'int'. 2320 // Although not in conformance with C99, we also allow the argument to be 2321 // an 'unsigned int' as that is a reasonably safe case. GCC also 2322 // doesn't emit a warning for that case. 2323 CoveredArgs.set(argIndex); 2324 const Expr *Arg = getDataArg(argIndex); 2325 if (!Arg) 2326 return false; 2327 2328 QualType T = Arg->getType(); 2329 2330 const analyze_printf::ArgType &AT = Amt.getArgType(S.Context); 2331 assert(AT.isValid()); 2332 2333 if (!AT.matchesType(S.Context, T)) { 2334 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type) 2335 << k << AT.getRepresentativeTypeName(S.Context) 2336 << T << Arg->getSourceRange(), 2337 getLocationOfByte(Amt.getStart()), 2338 /*IsStringLocation*/true, 2339 getSpecifierRange(startSpecifier, specifierLen)); 2340 // Don't do any more checking. We will just emit 2341 // spurious errors. 2342 return false; 2343 } 2344 } 2345 } 2346 return true; 2347} 2348 2349void CheckPrintfHandler::HandleInvalidAmount( 2350 const analyze_printf::PrintfSpecifier &FS, 2351 const analyze_printf::OptionalAmount &Amt, 2352 unsigned type, 2353 const char *startSpecifier, 2354 unsigned specifierLen) { 2355 const analyze_printf::PrintfConversionSpecifier &CS = 2356 FS.getConversionSpecifier(); 2357 2358 FixItHint fixit = 2359 Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant 2360 ? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(), 2361 Amt.getConstantLength())) 2362 : FixItHint(); 2363 2364 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount) 2365 << type << CS.toString(), 2366 getLocationOfByte(Amt.getStart()), 2367 /*IsStringLocation*/true, 2368 getSpecifierRange(startSpecifier, specifierLen), 2369 fixit); 2370} 2371 2372void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS, 2373 const analyze_printf::OptionalFlag &flag, 2374 const char *startSpecifier, 2375 unsigned specifierLen) { 2376 // Warn about pointless flag with a fixit removal. 2377 const analyze_printf::PrintfConversionSpecifier &CS = 2378 FS.getConversionSpecifier(); 2379 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag) 2380 << flag.toString() << CS.toString(), 2381 getLocationOfByte(flag.getPosition()), 2382 /*IsStringLocation*/true, 2383 getSpecifierRange(startSpecifier, specifierLen), 2384 FixItHint::CreateRemoval( 2385 getSpecifierRange(flag.getPosition(), 1))); 2386} 2387 2388void CheckPrintfHandler::HandleIgnoredFlag( 2389 const analyze_printf::PrintfSpecifier &FS, 2390 const analyze_printf::OptionalFlag &ignoredFlag, 2391 const analyze_printf::OptionalFlag &flag, 2392 const char *startSpecifier, 2393 unsigned specifierLen) { 2394 // Warn about ignored flag with a fixit removal. 2395 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag) 2396 << ignoredFlag.toString() << flag.toString(), 2397 getLocationOfByte(ignoredFlag.getPosition()), 2398 /*IsStringLocation*/true, 2399 getSpecifierRange(startSpecifier, specifierLen), 2400 FixItHint::CreateRemoval( 2401 getSpecifierRange(ignoredFlag.getPosition(), 1))); 2402} 2403 2404// Determines if the specified is a C++ class or struct containing 2405// a member with the specified name and kind (e.g. a CXXMethodDecl named 2406// "c_str()"). 2407template<typename MemberKind> 2408static llvm::SmallPtrSet<MemberKind*, 1> 2409CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) { 2410 const RecordType *RT = Ty->getAs<RecordType>(); 2411 llvm::SmallPtrSet<MemberKind*, 1> Results; 2412 2413 if (!RT) 2414 return Results; 2415 const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()); 2416 if (!RD) 2417 return Results; 2418 2419 LookupResult R(S, &S.PP.getIdentifierTable().get(Name), SourceLocation(), 2420 Sema::LookupMemberName); 2421 2422 // We just need to include all members of the right kind turned up by the 2423 // filter, at this point. 2424 if (S.LookupQualifiedName(R, RT->getDecl())) 2425 for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) { 2426 NamedDecl *decl = (*I)->getUnderlyingDecl(); 2427 if (MemberKind *FK = dyn_cast<MemberKind>(decl)) 2428 Results.insert(FK); 2429 } 2430 return Results; 2431} 2432 2433// Check if a (w)string was passed when a (w)char* was needed, and offer a 2434// better diagnostic if so. AT is assumed to be valid. 2435// Returns true when a c_str() conversion method is found. 2436bool CheckPrintfHandler::checkForCStrMembers( 2437 const analyze_printf::ArgType &AT, const Expr *E, 2438 const CharSourceRange &CSR) { 2439 typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet; 2440 2441 MethodSet Results = 2442 CXXRecordMembersNamed<CXXMethodDecl>("c_str", S, E->getType()); 2443 2444 for (MethodSet::iterator MI = Results.begin(), ME = Results.end(); 2445 MI != ME; ++MI) { 2446 const CXXMethodDecl *Method = *MI; 2447 if (Method->getNumParams() == 0 && 2448 AT.matchesType(S.Context, Method->getResultType())) { 2449 // FIXME: Suggest parens if the expression needs them. 2450 SourceLocation EndLoc = 2451 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()); 2452 S.Diag(E->getLocStart(), diag::note_printf_c_str) 2453 << "c_str()" 2454 << FixItHint::CreateInsertion(EndLoc, ".c_str()"); 2455 return true; 2456 } 2457 } 2458 2459 return false; 2460} 2461 2462bool 2463CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier 2464 &FS, 2465 const char *startSpecifier, 2466 unsigned specifierLen) { 2467 2468 using namespace analyze_format_string; 2469 using namespace analyze_printf; 2470 const PrintfConversionSpecifier &CS = FS.getConversionSpecifier(); 2471 2472 if (FS.consumesDataArgument()) { 2473 if (atFirstArg) { 2474 atFirstArg = false; 2475 usesPositionalArgs = FS.usesPositionalArg(); 2476 } 2477 else if (usesPositionalArgs != FS.usesPositionalArg()) { 2478 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 2479 startSpecifier, specifierLen); 2480 return false; 2481 } 2482 } 2483 2484 // First check if the field width, precision, and conversion specifier 2485 // have matching data arguments. 2486 if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0, 2487 startSpecifier, specifierLen)) { 2488 return false; 2489 } 2490 2491 if (!HandleAmount(FS.getPrecision(), /* precision */ 1, 2492 startSpecifier, specifierLen)) { 2493 return false; 2494 } 2495 2496 if (!CS.consumesDataArgument()) { 2497 // FIXME: Technically specifying a precision or field width here 2498 // makes no sense. Worth issuing a warning at some point. 2499 return true; 2500 } 2501 2502 // Consume the argument. 2503 unsigned argIndex = FS.getArgIndex(); 2504 if (argIndex < NumDataArgs) { 2505 // The check to see if the argIndex is valid will come later. 2506 // We set the bit here because we may exit early from this 2507 // function if we encounter some other error. 2508 CoveredArgs.set(argIndex); 2509 } 2510 2511 // Check for using an Objective-C specific conversion specifier 2512 // in a non-ObjC literal. 2513 if (!ObjCContext && CS.isObjCArg()) { 2514 return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier, 2515 specifierLen); 2516 } 2517 2518 // Check for invalid use of field width 2519 if (!FS.hasValidFieldWidth()) { 2520 HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0, 2521 startSpecifier, specifierLen); 2522 } 2523 2524 // Check for invalid use of precision 2525 if (!FS.hasValidPrecision()) { 2526 HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1, 2527 startSpecifier, specifierLen); 2528 } 2529 2530 // Check each flag does not conflict with any other component. 2531 if (!FS.hasValidThousandsGroupingPrefix()) 2532 HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen); 2533 if (!FS.hasValidLeadingZeros()) 2534 HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen); 2535 if (!FS.hasValidPlusPrefix()) 2536 HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen); 2537 if (!FS.hasValidSpacePrefix()) 2538 HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen); 2539 if (!FS.hasValidAlternativeForm()) 2540 HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen); 2541 if (!FS.hasValidLeftJustified()) 2542 HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen); 2543 2544 // Check that flags are not ignored by another flag 2545 if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+' 2546 HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(), 2547 startSpecifier, specifierLen); 2548 if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-' 2549 HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(), 2550 startSpecifier, specifierLen); 2551 2552 // Check the length modifier is valid with the given conversion specifier. 2553 const LengthModifier &LM = FS.getLengthModifier(); 2554 if (!FS.hasValidLengthModifier()) 2555 EmitFormatDiagnostic(S.PDiag(diag::warn_format_nonsensical_length) 2556 << LM.toString() << CS.toString(), 2557 getLocationOfByte(LM.getStart()), 2558 /*IsStringLocation*/true, 2559 getSpecifierRange(startSpecifier, specifierLen), 2560 FixItHint::CreateRemoval( 2561 getSpecifierRange(LM.getStart(), 2562 LM.getLength()))); 2563 if (!FS.hasStandardLengthModifier()) 2564 HandleNonStandardLengthModifier(LM, startSpecifier, specifierLen); 2565 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 2566 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 2567 if (!FS.hasStandardLengthConversionCombination()) 2568 HandleNonStandardConversionSpecification(LM, CS, startSpecifier, 2569 specifierLen); 2570 2571 // The remaining checks depend on the data arguments. 2572 if (HasVAListArg) 2573 return true; 2574 2575 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 2576 return false; 2577 2578 const Expr *Arg = getDataArg(argIndex); 2579 if (!Arg) 2580 return true; 2581 2582 return checkFormatExpr(FS, startSpecifier, specifierLen, Arg); 2583} 2584 2585bool 2586CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 2587 const char *StartSpecifier, 2588 unsigned SpecifierLen, 2589 const Expr *E) { 2590 using namespace analyze_format_string; 2591 using namespace analyze_printf; 2592 // Now type check the data expression that matches the 2593 // format specifier. 2594 const analyze_printf::ArgType &AT = FS.getArgType(S.Context, 2595 ObjCContext); 2596 if (AT.isValid() && !AT.matchesType(S.Context, E->getType())) { 2597 // Look through argument promotions for our error message's reported type. 2598 // This includes the integral and floating promotions, but excludes array 2599 // and function pointer decay; seeing that an argument intended to be a 2600 // string has type 'char [6]' is probably more confusing than 'char *'. 2601 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 2602 if (ICE->getCastKind() == CK_IntegralCast || 2603 ICE->getCastKind() == CK_FloatingCast) { 2604 E = ICE->getSubExpr(); 2605 2606 // Check if we didn't match because of an implicit cast from a 'char' 2607 // or 'short' to an 'int'. This is done because printf is a varargs 2608 // function. 2609 if (ICE->getType() == S.Context.IntTy || 2610 ICE->getType() == S.Context.UnsignedIntTy) { 2611 // All further checking is done on the subexpression. 2612 if (AT.matchesType(S.Context, E->getType())) 2613 return true; 2614 } 2615 } 2616 } 2617 2618 // We may be able to offer a FixItHint if it is a supported type. 2619 PrintfSpecifier fixedFS = FS; 2620 bool success = fixedFS.fixType(E->getType(), S.getLangOpts(), 2621 S.Context, ObjCContext); 2622 2623 if (success) { 2624 // Get the fix string from the fixed format specifier 2625 SmallString<16> buf; 2626 llvm::raw_svector_ostream os(buf); 2627 fixedFS.toString(os); 2628 2629 EmitFormatDiagnostic( 2630 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2631 << AT.getRepresentativeTypeName(S.Context) << E->getType() 2632 << E->getSourceRange(), 2633 E->getLocStart(), 2634 /*IsStringLocation*/false, 2635 getSpecifierRange(StartSpecifier, SpecifierLen), 2636 FixItHint::CreateReplacement( 2637 getSpecifierRange(StartSpecifier, SpecifierLen), 2638 os.str())); 2639 } else { 2640 const CharSourceRange &CSR = getSpecifierRange(StartSpecifier, 2641 SpecifierLen); 2642 // Since the warning for passing non-POD types to variadic functions 2643 // was deferred until now, we emit a warning for non-POD 2644 // arguments here. 2645 if (S.isValidVarArgType(E->getType()) == Sema::VAK_Invalid) { 2646 unsigned DiagKind; 2647 if (E->getType()->isObjCObjectType()) 2648 DiagKind = diag::err_cannot_pass_objc_interface_to_vararg_format; 2649 else 2650 DiagKind = diag::warn_non_pod_vararg_with_format_string; 2651 2652 EmitFormatDiagnostic( 2653 S.PDiag(DiagKind) 2654 << S.getLangOpts().CPlusPlus0x 2655 << E->getType() 2656 << CallType 2657 << AT.getRepresentativeTypeName(S.Context) 2658 << CSR 2659 << E->getSourceRange(), 2660 E->getLocStart(), /*IsStringLocation*/false, CSR); 2661 2662 checkForCStrMembers(AT, E, CSR); 2663 } else 2664 EmitFormatDiagnostic( 2665 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2666 << AT.getRepresentativeTypeName(S.Context) << E->getType() 2667 << CSR 2668 << E->getSourceRange(), 2669 E->getLocStart(), /*IsStringLocation*/false, CSR); 2670 } 2671 } 2672 2673 return true; 2674} 2675 2676//===--- CHECK: Scanf format string checking ------------------------------===// 2677 2678namespace { 2679class CheckScanfHandler : public CheckFormatHandler { 2680public: 2681 CheckScanfHandler(Sema &s, const StringLiteral *fexpr, 2682 const Expr *origFormatExpr, unsigned firstDataArg, 2683 unsigned numDataArgs, const char *beg, bool hasVAListArg, 2684 Expr **Args, unsigned NumArgs, 2685 unsigned formatIdx, bool inFunctionCall, 2686 Sema::VariadicCallType CallType) 2687 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 2688 numDataArgs, beg, hasVAListArg, 2689 Args, NumArgs, formatIdx, inFunctionCall, CallType) 2690 {} 2691 2692 bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS, 2693 const char *startSpecifier, 2694 unsigned specifierLen); 2695 2696 bool HandleInvalidScanfConversionSpecifier( 2697 const analyze_scanf::ScanfSpecifier &FS, 2698 const char *startSpecifier, 2699 unsigned specifierLen); 2700 2701 void HandleIncompleteScanList(const char *start, const char *end); 2702}; 2703} 2704 2705void CheckScanfHandler::HandleIncompleteScanList(const char *start, 2706 const char *end) { 2707 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete), 2708 getLocationOfByte(end), /*IsStringLocation*/true, 2709 getSpecifierRange(start, end - start)); 2710} 2711 2712bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier( 2713 const analyze_scanf::ScanfSpecifier &FS, 2714 const char *startSpecifier, 2715 unsigned specifierLen) { 2716 2717 const analyze_scanf::ScanfConversionSpecifier &CS = 2718 FS.getConversionSpecifier(); 2719 2720 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 2721 getLocationOfByte(CS.getStart()), 2722 startSpecifier, specifierLen, 2723 CS.getStart(), CS.getLength()); 2724} 2725 2726bool CheckScanfHandler::HandleScanfSpecifier( 2727 const analyze_scanf::ScanfSpecifier &FS, 2728 const char *startSpecifier, 2729 unsigned specifierLen) { 2730 2731 using namespace analyze_scanf; 2732 using namespace analyze_format_string; 2733 2734 const ScanfConversionSpecifier &CS = FS.getConversionSpecifier(); 2735 2736 // Handle case where '%' and '*' don't consume an argument. These shouldn't 2737 // be used to decide if we are using positional arguments consistently. 2738 if (FS.consumesDataArgument()) { 2739 if (atFirstArg) { 2740 atFirstArg = false; 2741 usesPositionalArgs = FS.usesPositionalArg(); 2742 } 2743 else if (usesPositionalArgs != FS.usesPositionalArg()) { 2744 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 2745 startSpecifier, specifierLen); 2746 return false; 2747 } 2748 } 2749 2750 // Check if the field with is non-zero. 2751 const OptionalAmount &Amt = FS.getFieldWidth(); 2752 if (Amt.getHowSpecified() == OptionalAmount::Constant) { 2753 if (Amt.getConstantAmount() == 0) { 2754 const CharSourceRange &R = getSpecifierRange(Amt.getStart(), 2755 Amt.getConstantLength()); 2756 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width), 2757 getLocationOfByte(Amt.getStart()), 2758 /*IsStringLocation*/true, R, 2759 FixItHint::CreateRemoval(R)); 2760 } 2761 } 2762 2763 if (!FS.consumesDataArgument()) { 2764 // FIXME: Technically specifying a precision or field width here 2765 // makes no sense. Worth issuing a warning at some point. 2766 return true; 2767 } 2768 2769 // Consume the argument. 2770 unsigned argIndex = FS.getArgIndex(); 2771 if (argIndex < NumDataArgs) { 2772 // The check to see if the argIndex is valid will come later. 2773 // We set the bit here because we may exit early from this 2774 // function if we encounter some other error. 2775 CoveredArgs.set(argIndex); 2776 } 2777 2778 // Check the length modifier is valid with the given conversion specifier. 2779 const LengthModifier &LM = FS.getLengthModifier(); 2780 if (!FS.hasValidLengthModifier()) { 2781 const CharSourceRange &R = getSpecifierRange(LM.getStart(), LM.getLength()); 2782 EmitFormatDiagnostic(S.PDiag(diag::warn_format_nonsensical_length) 2783 << LM.toString() << CS.toString() 2784 << getSpecifierRange(startSpecifier, specifierLen), 2785 getLocationOfByte(LM.getStart()), 2786 /*IsStringLocation*/true, R, 2787 FixItHint::CreateRemoval(R)); 2788 } 2789 2790 if (!FS.hasStandardLengthModifier()) 2791 HandleNonStandardLengthModifier(LM, startSpecifier, specifierLen); 2792 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 2793 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 2794 if (!FS.hasStandardLengthConversionCombination()) 2795 HandleNonStandardConversionSpecification(LM, CS, startSpecifier, 2796 specifierLen); 2797 2798 // The remaining checks depend on the data arguments. 2799 if (HasVAListArg) 2800 return true; 2801 2802 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 2803 return false; 2804 2805 // Check that the argument type matches the format specifier. 2806 const Expr *Ex = getDataArg(argIndex); 2807 if (!Ex) 2808 return true; 2809 2810 const analyze_format_string::ArgType &AT = FS.getArgType(S.Context); 2811 if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType())) { 2812 ScanfSpecifier fixedFS = FS; 2813 bool success = fixedFS.fixType(Ex->getType(), S.getLangOpts(), 2814 S.Context); 2815 2816 if (success) { 2817 // Get the fix string from the fixed format specifier. 2818 SmallString<128> buf; 2819 llvm::raw_svector_ostream os(buf); 2820 fixedFS.toString(os); 2821 2822 EmitFormatDiagnostic( 2823 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2824 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() 2825 << Ex->getSourceRange(), 2826 Ex->getLocStart(), 2827 /*IsStringLocation*/false, 2828 getSpecifierRange(startSpecifier, specifierLen), 2829 FixItHint::CreateReplacement( 2830 getSpecifierRange(startSpecifier, specifierLen), 2831 os.str())); 2832 } else { 2833 EmitFormatDiagnostic( 2834 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2835 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() 2836 << Ex->getSourceRange(), 2837 Ex->getLocStart(), 2838 /*IsStringLocation*/false, 2839 getSpecifierRange(startSpecifier, specifierLen)); 2840 } 2841 } 2842 2843 return true; 2844} 2845 2846void Sema::CheckFormatString(const StringLiteral *FExpr, 2847 const Expr *OrigFormatExpr, 2848 Expr **Args, unsigned NumArgs, 2849 bool HasVAListArg, unsigned format_idx, 2850 unsigned firstDataArg, FormatStringType Type, 2851 bool inFunctionCall, VariadicCallType CallType) { 2852 2853 // CHECK: is the format string a wide literal? 2854 if (!FExpr->isAscii() && !FExpr->isUTF8()) { 2855 CheckFormatHandler::EmitFormatDiagnostic( 2856 *this, inFunctionCall, Args[format_idx], 2857 PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(), 2858 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 2859 return; 2860 } 2861 2862 // Str - The format string. NOTE: this is NOT null-terminated! 2863 StringRef StrRef = FExpr->getString(); 2864 const char *Str = StrRef.data(); 2865 unsigned StrLen = StrRef.size(); 2866 const unsigned numDataArgs = NumArgs - firstDataArg; 2867 2868 // CHECK: empty format string? 2869 if (StrLen == 0 && numDataArgs > 0) { 2870 CheckFormatHandler::EmitFormatDiagnostic( 2871 *this, inFunctionCall, Args[format_idx], 2872 PDiag(diag::warn_empty_format_string), FExpr->getLocStart(), 2873 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 2874 return; 2875 } 2876 2877 if (Type == FST_Printf || Type == FST_NSString) { 2878 CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 2879 numDataArgs, (Type == FST_NSString), 2880 Str, HasVAListArg, Args, NumArgs, format_idx, 2881 inFunctionCall, CallType); 2882 2883 if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen, 2884 getLangOpts())) 2885 H.DoneProcessing(); 2886 } else if (Type == FST_Scanf) { 2887 CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, numDataArgs, 2888 Str, HasVAListArg, Args, NumArgs, format_idx, 2889 inFunctionCall, CallType); 2890 2891 if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen, 2892 getLangOpts())) 2893 H.DoneProcessing(); 2894 } // TODO: handle other formats 2895} 2896 2897//===--- CHECK: Standard memory functions ---------------------------------===// 2898 2899/// \brief Determine whether the given type is a dynamic class type (e.g., 2900/// whether it has a vtable). 2901static bool isDynamicClassType(QualType T) { 2902 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) 2903 if (CXXRecordDecl *Definition = Record->getDefinition()) 2904 if (Definition->isDynamicClass()) 2905 return true; 2906 2907 return false; 2908} 2909 2910/// \brief If E is a sizeof expression, returns its argument expression, 2911/// otherwise returns NULL. 2912static const Expr *getSizeOfExprArg(const Expr* E) { 2913 if (const UnaryExprOrTypeTraitExpr *SizeOf = 2914 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 2915 if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType()) 2916 return SizeOf->getArgumentExpr()->IgnoreParenImpCasts(); 2917 2918 return 0; 2919} 2920 2921/// \brief If E is a sizeof expression, returns its argument type. 2922static QualType getSizeOfArgType(const Expr* E) { 2923 if (const UnaryExprOrTypeTraitExpr *SizeOf = 2924 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 2925 if (SizeOf->getKind() == clang::UETT_SizeOf) 2926 return SizeOf->getTypeOfArgument(); 2927 2928 return QualType(); 2929} 2930 2931/// \brief Check for dangerous or invalid arguments to memset(). 2932/// 2933/// This issues warnings on known problematic, dangerous or unspecified 2934/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp' 2935/// function calls. 2936/// 2937/// \param Call The call expression to diagnose. 2938void Sema::CheckMemaccessArguments(const CallExpr *Call, 2939 unsigned BId, 2940 IdentifierInfo *FnName) { 2941 assert(BId != 0); 2942 2943 // It is possible to have a non-standard definition of memset. Validate 2944 // we have enough arguments, and if not, abort further checking. 2945 unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3); 2946 if (Call->getNumArgs() < ExpectedNumArgs) 2947 return; 2948 2949 unsigned LastArg = (BId == Builtin::BImemset || 2950 BId == Builtin::BIstrndup ? 1 : 2); 2951 unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2); 2952 const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts(); 2953 2954 // We have special checking when the length is a sizeof expression. 2955 QualType SizeOfArgTy = getSizeOfArgType(LenExpr); 2956 const Expr *SizeOfArg = getSizeOfExprArg(LenExpr); 2957 llvm::FoldingSetNodeID SizeOfArgID; 2958 2959 for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) { 2960 const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts(); 2961 SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange(); 2962 2963 QualType DestTy = Dest->getType(); 2964 if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) { 2965 QualType PointeeTy = DestPtrTy->getPointeeType(); 2966 2967 // Never warn about void type pointers. This can be used to suppress 2968 // false positives. 2969 if (PointeeTy->isVoidType()) 2970 continue; 2971 2972 // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by 2973 // actually comparing the expressions for equality. Because computing the 2974 // expression IDs can be expensive, we only do this if the diagnostic is 2975 // enabled. 2976 if (SizeOfArg && 2977 Diags.getDiagnosticLevel(diag::warn_sizeof_pointer_expr_memaccess, 2978 SizeOfArg->getExprLoc())) { 2979 // We only compute IDs for expressions if the warning is enabled, and 2980 // cache the sizeof arg's ID. 2981 if (SizeOfArgID == llvm::FoldingSetNodeID()) 2982 SizeOfArg->Profile(SizeOfArgID, Context, true); 2983 llvm::FoldingSetNodeID DestID; 2984 Dest->Profile(DestID, Context, true); 2985 if (DestID == SizeOfArgID) { 2986 // TODO: For strncpy() and friends, this could suggest sizeof(dst) 2987 // over sizeof(src) as well. 2988 unsigned ActionIdx = 0; // Default is to suggest dereferencing. 2989 StringRef ReadableName = FnName->getName(); 2990 2991 if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest)) 2992 if (UnaryOp->getOpcode() == UO_AddrOf) 2993 ActionIdx = 1; // If its an address-of operator, just remove it. 2994 if (Context.getTypeSize(PointeeTy) == Context.getCharWidth()) 2995 ActionIdx = 2; // If the pointee's size is sizeof(char), 2996 // suggest an explicit length. 2997 2998 // If the function is defined as a builtin macro, do not show macro 2999 // expansion. 3000 SourceLocation SL = SizeOfArg->getExprLoc(); 3001 SourceRange DSR = Dest->getSourceRange(); 3002 SourceRange SSR = SizeOfArg->getSourceRange(); 3003 SourceManager &SM = PP.getSourceManager(); 3004 3005 if (SM.isMacroArgExpansion(SL)) { 3006 ReadableName = Lexer::getImmediateMacroName(SL, SM, LangOpts); 3007 SL = SM.getSpellingLoc(SL); 3008 DSR = SourceRange(SM.getSpellingLoc(DSR.getBegin()), 3009 SM.getSpellingLoc(DSR.getEnd())); 3010 SSR = SourceRange(SM.getSpellingLoc(SSR.getBegin()), 3011 SM.getSpellingLoc(SSR.getEnd())); 3012 } 3013 3014 DiagRuntimeBehavior(SL, SizeOfArg, 3015 PDiag(diag::warn_sizeof_pointer_expr_memaccess) 3016 << ReadableName 3017 << PointeeTy 3018 << DestTy 3019 << DSR 3020 << SSR); 3021 DiagRuntimeBehavior(SL, SizeOfArg, 3022 PDiag(diag::warn_sizeof_pointer_expr_memaccess_note) 3023 << ActionIdx 3024 << SSR); 3025 3026 break; 3027 } 3028 } 3029 3030 // Also check for cases where the sizeof argument is the exact same 3031 // type as the memory argument, and where it points to a user-defined 3032 // record type. 3033 if (SizeOfArgTy != QualType()) { 3034 if (PointeeTy->isRecordType() && 3035 Context.typesAreCompatible(SizeOfArgTy, DestTy)) { 3036 DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest, 3037 PDiag(diag::warn_sizeof_pointer_type_memaccess) 3038 << FnName << SizeOfArgTy << ArgIdx 3039 << PointeeTy << Dest->getSourceRange() 3040 << LenExpr->getSourceRange()); 3041 break; 3042 } 3043 } 3044 3045 // Always complain about dynamic classes. 3046 if (isDynamicClassType(PointeeTy)) { 3047 3048 unsigned OperationType = 0; 3049 // "overwritten" if we're warning about the destination for any call 3050 // but memcmp; otherwise a verb appropriate to the call. 3051 if (ArgIdx != 0 || BId == Builtin::BImemcmp) { 3052 if (BId == Builtin::BImemcpy) 3053 OperationType = 1; 3054 else if(BId == Builtin::BImemmove) 3055 OperationType = 2; 3056 else if (BId == Builtin::BImemcmp) 3057 OperationType = 3; 3058 } 3059 3060 DiagRuntimeBehavior( 3061 Dest->getExprLoc(), Dest, 3062 PDiag(diag::warn_dyn_class_memaccess) 3063 << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx) 3064 << FnName << PointeeTy 3065 << OperationType 3066 << Call->getCallee()->getSourceRange()); 3067 } else if (PointeeTy.hasNonTrivialObjCLifetime() && 3068 BId != Builtin::BImemset) 3069 DiagRuntimeBehavior( 3070 Dest->getExprLoc(), Dest, 3071 PDiag(diag::warn_arc_object_memaccess) 3072 << ArgIdx << FnName << PointeeTy 3073 << Call->getCallee()->getSourceRange()); 3074 else 3075 continue; 3076 3077 DiagRuntimeBehavior( 3078 Dest->getExprLoc(), Dest, 3079 PDiag(diag::note_bad_memaccess_silence) 3080 << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)")); 3081 break; 3082 } 3083 } 3084} 3085 3086// A little helper routine: ignore addition and subtraction of integer literals. 3087// This intentionally does not ignore all integer constant expressions because 3088// we don't want to remove sizeof(). 3089static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) { 3090 Ex = Ex->IgnoreParenCasts(); 3091 3092 for (;;) { 3093 const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex); 3094 if (!BO || !BO->isAdditiveOp()) 3095 break; 3096 3097 const Expr *RHS = BO->getRHS()->IgnoreParenCasts(); 3098 const Expr *LHS = BO->getLHS()->IgnoreParenCasts(); 3099 3100 if (isa<IntegerLiteral>(RHS)) 3101 Ex = LHS; 3102 else if (isa<IntegerLiteral>(LHS)) 3103 Ex = RHS; 3104 else 3105 break; 3106 } 3107 3108 return Ex; 3109} 3110 3111static bool isConstantSizeArrayWithMoreThanOneElement(QualType Ty, 3112 ASTContext &Context) { 3113 // Only handle constant-sized or VLAs, but not flexible members. 3114 if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(Ty)) { 3115 // Only issue the FIXIT for arrays of size > 1. 3116 if (CAT->getSize().getSExtValue() <= 1) 3117 return false; 3118 } else if (!Ty->isVariableArrayType()) { 3119 return false; 3120 } 3121 return true; 3122} 3123 3124// Warn if the user has made the 'size' argument to strlcpy or strlcat 3125// be the size of the source, instead of the destination. 3126void Sema::CheckStrlcpycatArguments(const CallExpr *Call, 3127 IdentifierInfo *FnName) { 3128 3129 // Don't crash if the user has the wrong number of arguments 3130 if (Call->getNumArgs() != 3) 3131 return; 3132 3133 const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context); 3134 const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context); 3135 const Expr *CompareWithSrc = NULL; 3136 3137 // Look for 'strlcpy(dst, x, sizeof(x))' 3138 if (const Expr *Ex = getSizeOfExprArg(SizeArg)) 3139 CompareWithSrc = Ex; 3140 else { 3141 // Look for 'strlcpy(dst, x, strlen(x))' 3142 if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) { 3143 if (SizeCall->isBuiltinCall() == Builtin::BIstrlen 3144 && SizeCall->getNumArgs() == 1) 3145 CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context); 3146 } 3147 } 3148 3149 if (!CompareWithSrc) 3150 return; 3151 3152 // Determine if the argument to sizeof/strlen is equal to the source 3153 // argument. In principle there's all kinds of things you could do 3154 // here, for instance creating an == expression and evaluating it with 3155 // EvaluateAsBooleanCondition, but this uses a more direct technique: 3156 const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg); 3157 if (!SrcArgDRE) 3158 return; 3159 3160 const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc); 3161 if (!CompareWithSrcDRE || 3162 SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl()) 3163 return; 3164 3165 const Expr *OriginalSizeArg = Call->getArg(2); 3166 Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size) 3167 << OriginalSizeArg->getSourceRange() << FnName; 3168 3169 // Output a FIXIT hint if the destination is an array (rather than a 3170 // pointer to an array). This could be enhanced to handle some 3171 // pointers if we know the actual size, like if DstArg is 'array+2' 3172 // we could say 'sizeof(array)-2'. 3173 const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts(); 3174 if (!isConstantSizeArrayWithMoreThanOneElement(DstArg->getType(), Context)) 3175 return; 3176 3177 SmallString<128> sizeString; 3178 llvm::raw_svector_ostream OS(sizeString); 3179 OS << "sizeof("; 3180 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3181 OS << ")"; 3182 3183 Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size) 3184 << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(), 3185 OS.str()); 3186} 3187 3188/// Check if two expressions refer to the same declaration. 3189static bool referToTheSameDecl(const Expr *E1, const Expr *E2) { 3190 if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1)) 3191 if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2)) 3192 return D1->getDecl() == D2->getDecl(); 3193 return false; 3194} 3195 3196static const Expr *getStrlenExprArg(const Expr *E) { 3197 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 3198 const FunctionDecl *FD = CE->getDirectCallee(); 3199 if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen) 3200 return 0; 3201 return CE->getArg(0)->IgnoreParenCasts(); 3202 } 3203 return 0; 3204} 3205 3206// Warn on anti-patterns as the 'size' argument to strncat. 3207// The correct size argument should look like following: 3208// strncat(dst, src, sizeof(dst) - strlen(dest) - 1); 3209void Sema::CheckStrncatArguments(const CallExpr *CE, 3210 IdentifierInfo *FnName) { 3211 // Don't crash if the user has the wrong number of arguments. 3212 if (CE->getNumArgs() < 3) 3213 return; 3214 const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts(); 3215 const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts(); 3216 const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts(); 3217 3218 // Identify common expressions, which are wrongly used as the size argument 3219 // to strncat and may lead to buffer overflows. 3220 unsigned PatternType = 0; 3221 if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) { 3222 // - sizeof(dst) 3223 if (referToTheSameDecl(SizeOfArg, DstArg)) 3224 PatternType = 1; 3225 // - sizeof(src) 3226 else if (referToTheSameDecl(SizeOfArg, SrcArg)) 3227 PatternType = 2; 3228 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) { 3229 if (BE->getOpcode() == BO_Sub) { 3230 const Expr *L = BE->getLHS()->IgnoreParenCasts(); 3231 const Expr *R = BE->getRHS()->IgnoreParenCasts(); 3232 // - sizeof(dst) - strlen(dst) 3233 if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) && 3234 referToTheSameDecl(DstArg, getStrlenExprArg(R))) 3235 PatternType = 1; 3236 // - sizeof(src) - (anything) 3237 else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L))) 3238 PatternType = 2; 3239 } 3240 } 3241 3242 if (PatternType == 0) 3243 return; 3244 3245 // Generate the diagnostic. 3246 SourceLocation SL = LenArg->getLocStart(); 3247 SourceRange SR = LenArg->getSourceRange(); 3248 SourceManager &SM = PP.getSourceManager(); 3249 3250 // If the function is defined as a builtin macro, do not show macro expansion. 3251 if (SM.isMacroArgExpansion(SL)) { 3252 SL = SM.getSpellingLoc(SL); 3253 SR = SourceRange(SM.getSpellingLoc(SR.getBegin()), 3254 SM.getSpellingLoc(SR.getEnd())); 3255 } 3256 3257 // Check if the destination is an array (rather than a pointer to an array). 3258 QualType DstTy = DstArg->getType(); 3259 bool isKnownSizeArray = isConstantSizeArrayWithMoreThanOneElement(DstTy, 3260 Context); 3261 if (!isKnownSizeArray) { 3262 if (PatternType == 1) 3263 Diag(SL, diag::warn_strncat_wrong_size) << SR; 3264 else 3265 Diag(SL, diag::warn_strncat_src_size) << SR; 3266 return; 3267 } 3268 3269 if (PatternType == 1) 3270 Diag(SL, diag::warn_strncat_large_size) << SR; 3271 else 3272 Diag(SL, diag::warn_strncat_src_size) << SR; 3273 3274 SmallString<128> sizeString; 3275 llvm::raw_svector_ostream OS(sizeString); 3276 OS << "sizeof("; 3277 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3278 OS << ") - "; 3279 OS << "strlen("; 3280 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3281 OS << ") - 1"; 3282 3283 Diag(SL, diag::note_strncat_wrong_size) 3284 << FixItHint::CreateReplacement(SR, OS.str()); 3285} 3286 3287//===--- CHECK: Return Address of Stack Variable --------------------------===// 3288 3289static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3290 Decl *ParentDecl); 3291static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars, 3292 Decl *ParentDecl); 3293 3294/// CheckReturnStackAddr - Check if a return statement returns the address 3295/// of a stack variable. 3296void 3297Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType, 3298 SourceLocation ReturnLoc) { 3299 3300 Expr *stackE = 0; 3301 SmallVector<DeclRefExpr *, 8> refVars; 3302 3303 // Perform checking for returned stack addresses, local blocks, 3304 // label addresses or references to temporaries. 3305 if (lhsType->isPointerType() || 3306 (!getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) { 3307 stackE = EvalAddr(RetValExp, refVars, /*ParentDecl=*/0); 3308 } else if (lhsType->isReferenceType()) { 3309 stackE = EvalVal(RetValExp, refVars, /*ParentDecl=*/0); 3310 } 3311 3312 if (stackE == 0) 3313 return; // Nothing suspicious was found. 3314 3315 SourceLocation diagLoc; 3316 SourceRange diagRange; 3317 if (refVars.empty()) { 3318 diagLoc = stackE->getLocStart(); 3319 diagRange = stackE->getSourceRange(); 3320 } else { 3321 // We followed through a reference variable. 'stackE' contains the 3322 // problematic expression but we will warn at the return statement pointing 3323 // at the reference variable. We will later display the "trail" of 3324 // reference variables using notes. 3325 diagLoc = refVars[0]->getLocStart(); 3326 diagRange = refVars[0]->getSourceRange(); 3327 } 3328 3329 if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var. 3330 Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref 3331 : diag::warn_ret_stack_addr) 3332 << DR->getDecl()->getDeclName() << diagRange; 3333 } else if (isa<BlockExpr>(stackE)) { // local block. 3334 Diag(diagLoc, diag::err_ret_local_block) << diagRange; 3335 } else if (isa<AddrLabelExpr>(stackE)) { // address of label. 3336 Diag(diagLoc, diag::warn_ret_addr_label) << diagRange; 3337 } else { // local temporary. 3338 Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref 3339 : diag::warn_ret_local_temp_addr) 3340 << diagRange; 3341 } 3342 3343 // Display the "trail" of reference variables that we followed until we 3344 // found the problematic expression using notes. 3345 for (unsigned i = 0, e = refVars.size(); i != e; ++i) { 3346 VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl()); 3347 // If this var binds to another reference var, show the range of the next 3348 // var, otherwise the var binds to the problematic expression, in which case 3349 // show the range of the expression. 3350 SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange() 3351 : stackE->getSourceRange(); 3352 Diag(VD->getLocation(), diag::note_ref_var_local_bind) 3353 << VD->getDeclName() << range; 3354 } 3355} 3356 3357/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that 3358/// check if the expression in a return statement evaluates to an address 3359/// to a location on the stack, a local block, an address of a label, or a 3360/// reference to local temporary. The recursion is used to traverse the 3361/// AST of the return expression, with recursion backtracking when we 3362/// encounter a subexpression that (1) clearly does not lead to one of the 3363/// above problematic expressions (2) is something we cannot determine leads to 3364/// a problematic expression based on such local checking. 3365/// 3366/// Both EvalAddr and EvalVal follow through reference variables to evaluate 3367/// the expression that they point to. Such variables are added to the 3368/// 'refVars' vector so that we know what the reference variable "trail" was. 3369/// 3370/// EvalAddr processes expressions that are pointers that are used as 3371/// references (and not L-values). EvalVal handles all other values. 3372/// At the base case of the recursion is a check for the above problematic 3373/// expressions. 3374/// 3375/// This implementation handles: 3376/// 3377/// * pointer-to-pointer casts 3378/// * implicit conversions from array references to pointers 3379/// * taking the address of fields 3380/// * arbitrary interplay between "&" and "*" operators 3381/// * pointer arithmetic from an address of a stack variable 3382/// * taking the address of an array element where the array is on the stack 3383static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3384 Decl *ParentDecl) { 3385 if (E->isTypeDependent()) 3386 return NULL; 3387 3388 // We should only be called for evaluating pointer expressions. 3389 assert((E->getType()->isAnyPointerType() || 3390 E->getType()->isBlockPointerType() || 3391 E->getType()->isObjCQualifiedIdType()) && 3392 "EvalAddr only works on pointers"); 3393 3394 E = E->IgnoreParens(); 3395 3396 // Our "symbolic interpreter" is just a dispatch off the currently 3397 // viewed AST node. We then recursively traverse the AST by calling 3398 // EvalAddr and EvalVal appropriately. 3399 switch (E->getStmtClass()) { 3400 case Stmt::DeclRefExprClass: { 3401 DeclRefExpr *DR = cast<DeclRefExpr>(E); 3402 3403 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) 3404 // If this is a reference variable, follow through to the expression that 3405 // it points to. 3406 if (V->hasLocalStorage() && 3407 V->getType()->isReferenceType() && V->hasInit()) { 3408 // Add the reference variable to the "trail". 3409 refVars.push_back(DR); 3410 return EvalAddr(V->getInit(), refVars, ParentDecl); 3411 } 3412 3413 return NULL; 3414 } 3415 3416 case Stmt::UnaryOperatorClass: { 3417 // The only unary operator that make sense to handle here 3418 // is AddrOf. All others don't make sense as pointers. 3419 UnaryOperator *U = cast<UnaryOperator>(E); 3420 3421 if (U->getOpcode() == UO_AddrOf) 3422 return EvalVal(U->getSubExpr(), refVars, ParentDecl); 3423 else 3424 return NULL; 3425 } 3426 3427 case Stmt::BinaryOperatorClass: { 3428 // Handle pointer arithmetic. All other binary operators are not valid 3429 // in this context. 3430 BinaryOperator *B = cast<BinaryOperator>(E); 3431 BinaryOperatorKind op = B->getOpcode(); 3432 3433 if (op != BO_Add && op != BO_Sub) 3434 return NULL; 3435 3436 Expr *Base = B->getLHS(); 3437 3438 // Determine which argument is the real pointer base. It could be 3439 // the RHS argument instead of the LHS. 3440 if (!Base->getType()->isPointerType()) Base = B->getRHS(); 3441 3442 assert (Base->getType()->isPointerType()); 3443 return EvalAddr(Base, refVars, ParentDecl); 3444 } 3445 3446 // For conditional operators we need to see if either the LHS or RHS are 3447 // valid DeclRefExpr*s. If one of them is valid, we return it. 3448 case Stmt::ConditionalOperatorClass: { 3449 ConditionalOperator *C = cast<ConditionalOperator>(E); 3450 3451 // Handle the GNU extension for missing LHS. 3452 if (Expr *lhsExpr = C->getLHS()) { 3453 // In C++, we can have a throw-expression, which has 'void' type. 3454 if (!lhsExpr->getType()->isVoidType()) 3455 if (Expr* LHS = EvalAddr(lhsExpr, refVars, ParentDecl)) 3456 return LHS; 3457 } 3458 3459 // In C++, we can have a throw-expression, which has 'void' type. 3460 if (C->getRHS()->getType()->isVoidType()) 3461 return NULL; 3462 3463 return EvalAddr(C->getRHS(), refVars, ParentDecl); 3464 } 3465 3466 case Stmt::BlockExprClass: 3467 if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures()) 3468 return E; // local block. 3469 return NULL; 3470 3471 case Stmt::AddrLabelExprClass: 3472 return E; // address of label. 3473 3474 case Stmt::ExprWithCleanupsClass: 3475 return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars, 3476 ParentDecl); 3477 3478 // For casts, we need to handle conversions from arrays to 3479 // pointer values, and pointer-to-pointer conversions. 3480 case Stmt::ImplicitCastExprClass: 3481 case Stmt::CStyleCastExprClass: 3482 case Stmt::CXXFunctionalCastExprClass: 3483 case Stmt::ObjCBridgedCastExprClass: 3484 case Stmt::CXXStaticCastExprClass: 3485 case Stmt::CXXDynamicCastExprClass: 3486 case Stmt::CXXConstCastExprClass: 3487 case Stmt::CXXReinterpretCastExprClass: { 3488 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr(); 3489 switch (cast<CastExpr>(E)->getCastKind()) { 3490 case CK_BitCast: 3491 case CK_LValueToRValue: 3492 case CK_NoOp: 3493 case CK_BaseToDerived: 3494 case CK_DerivedToBase: 3495 case CK_UncheckedDerivedToBase: 3496 case CK_Dynamic: 3497 case CK_CPointerToObjCPointerCast: 3498 case CK_BlockPointerToObjCPointerCast: 3499 case CK_AnyPointerToBlockPointerCast: 3500 return EvalAddr(SubExpr, refVars, ParentDecl); 3501 3502 case CK_ArrayToPointerDecay: 3503 return EvalVal(SubExpr, refVars, ParentDecl); 3504 3505 default: 3506 return 0; 3507 } 3508 } 3509 3510 case Stmt::MaterializeTemporaryExprClass: 3511 if (Expr *Result = EvalAddr( 3512 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 3513 refVars, ParentDecl)) 3514 return Result; 3515 3516 return E; 3517 3518 // Everything else: we simply don't reason about them. 3519 default: 3520 return NULL; 3521 } 3522} 3523 3524 3525/// EvalVal - This function is complements EvalAddr in the mutual recursion. 3526/// See the comments for EvalAddr for more details. 3527static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3528 Decl *ParentDecl) { 3529do { 3530 // We should only be called for evaluating non-pointer expressions, or 3531 // expressions with a pointer type that are not used as references but instead 3532 // are l-values (e.g., DeclRefExpr with a pointer type). 3533 3534 // Our "symbolic interpreter" is just a dispatch off the currently 3535 // viewed AST node. We then recursively traverse the AST by calling 3536 // EvalAddr and EvalVal appropriately. 3537 3538 E = E->IgnoreParens(); 3539 switch (E->getStmtClass()) { 3540 case Stmt::ImplicitCastExprClass: { 3541 ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E); 3542 if (IE->getValueKind() == VK_LValue) { 3543 E = IE->getSubExpr(); 3544 continue; 3545 } 3546 return NULL; 3547 } 3548 3549 case Stmt::ExprWithCleanupsClass: 3550 return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,ParentDecl); 3551 3552 case Stmt::DeclRefExprClass: { 3553 // When we hit a DeclRefExpr we are looking at code that refers to a 3554 // variable's name. If it's not a reference variable we check if it has 3555 // local storage within the function, and if so, return the expression. 3556 DeclRefExpr *DR = cast<DeclRefExpr>(E); 3557 3558 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) { 3559 // Check if it refers to itself, e.g. "int& i = i;". 3560 if (V == ParentDecl) 3561 return DR; 3562 3563 if (V->hasLocalStorage()) { 3564 if (!V->getType()->isReferenceType()) 3565 return DR; 3566 3567 // Reference variable, follow through to the expression that 3568 // it points to. 3569 if (V->hasInit()) { 3570 // Add the reference variable to the "trail". 3571 refVars.push_back(DR); 3572 return EvalVal(V->getInit(), refVars, V); 3573 } 3574 } 3575 } 3576 3577 return NULL; 3578 } 3579 3580 case Stmt::UnaryOperatorClass: { 3581 // The only unary operator that make sense to handle here 3582 // is Deref. All others don't resolve to a "name." This includes 3583 // handling all sorts of rvalues passed to a unary operator. 3584 UnaryOperator *U = cast<UnaryOperator>(E); 3585 3586 if (U->getOpcode() == UO_Deref) 3587 return EvalAddr(U->getSubExpr(), refVars, ParentDecl); 3588 3589 return NULL; 3590 } 3591 3592 case Stmt::ArraySubscriptExprClass: { 3593 // Array subscripts are potential references to data on the stack. We 3594 // retrieve the DeclRefExpr* for the array variable if it indeed 3595 // has local storage. 3596 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars,ParentDecl); 3597 } 3598 3599 case Stmt::ConditionalOperatorClass: { 3600 // For conditional operators we need to see if either the LHS or RHS are 3601 // non-NULL Expr's. If one is non-NULL, we return it. 3602 ConditionalOperator *C = cast<ConditionalOperator>(E); 3603 3604 // Handle the GNU extension for missing LHS. 3605 if (Expr *lhsExpr = C->getLHS()) 3606 if (Expr *LHS = EvalVal(lhsExpr, refVars, ParentDecl)) 3607 return LHS; 3608 3609 return EvalVal(C->getRHS(), refVars, ParentDecl); 3610 } 3611 3612 // Accesses to members are potential references to data on the stack. 3613 case Stmt::MemberExprClass: { 3614 MemberExpr *M = cast<MemberExpr>(E); 3615 3616 // Check for indirect access. We only want direct field accesses. 3617 if (M->isArrow()) 3618 return NULL; 3619 3620 // Check whether the member type is itself a reference, in which case 3621 // we're not going to refer to the member, but to what the member refers to. 3622 if (M->getMemberDecl()->getType()->isReferenceType()) 3623 return NULL; 3624 3625 return EvalVal(M->getBase(), refVars, ParentDecl); 3626 } 3627 3628 case Stmt::MaterializeTemporaryExprClass: 3629 if (Expr *Result = EvalVal( 3630 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 3631 refVars, ParentDecl)) 3632 return Result; 3633 3634 return E; 3635 3636 default: 3637 // Check that we don't return or take the address of a reference to a 3638 // temporary. This is only useful in C++. 3639 if (!E->isTypeDependent() && E->isRValue()) 3640 return E; 3641 3642 // Everything else: we simply don't reason about them. 3643 return NULL; 3644 } 3645} while (true); 3646} 3647 3648//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===// 3649 3650/// Check for comparisons of floating point operands using != and ==. 3651/// Issue a warning if these are no self-comparisons, as they are not likely 3652/// to do what the programmer intended. 3653void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) { 3654 Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts(); 3655 Expr* RightExprSansParen = RHS->IgnoreParenImpCasts(); 3656 3657 // Special case: check for x == x (which is OK). 3658 // Do not emit warnings for such cases. 3659 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen)) 3660 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen)) 3661 if (DRL->getDecl() == DRR->getDecl()) 3662 return; 3663 3664 3665 // Special case: check for comparisons against literals that can be exactly 3666 // represented by APFloat. In such cases, do not emit a warning. This 3667 // is a heuristic: often comparison against such literals are used to 3668 // detect if a value in a variable has not changed. This clearly can 3669 // lead to false negatives. 3670 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) { 3671 if (FLL->isExact()) 3672 return; 3673 } else 3674 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)) 3675 if (FLR->isExact()) 3676 return; 3677 3678 // Check for comparisons with builtin types. 3679 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen)) 3680 if (CL->isBuiltinCall()) 3681 return; 3682 3683 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen)) 3684 if (CR->isBuiltinCall()) 3685 return; 3686 3687 // Emit the diagnostic. 3688 Diag(Loc, diag::warn_floatingpoint_eq) 3689 << LHS->getSourceRange() << RHS->getSourceRange(); 3690} 3691 3692//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===// 3693//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===// 3694 3695namespace { 3696 3697/// Structure recording the 'active' range of an integer-valued 3698/// expression. 3699struct IntRange { 3700 /// The number of bits active in the int. 3701 unsigned Width; 3702 3703 /// True if the int is known not to have negative values. 3704 bool NonNegative; 3705 3706 IntRange(unsigned Width, bool NonNegative) 3707 : Width(Width), NonNegative(NonNegative) 3708 {} 3709 3710 /// Returns the range of the bool type. 3711 static IntRange forBoolType() { 3712 return IntRange(1, true); 3713 } 3714 3715 /// Returns the range of an opaque value of the given integral type. 3716 static IntRange forValueOfType(ASTContext &C, QualType T) { 3717 return forValueOfCanonicalType(C, 3718 T->getCanonicalTypeInternal().getTypePtr()); 3719 } 3720 3721 /// Returns the range of an opaque value of a canonical integral type. 3722 static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) { 3723 assert(T->isCanonicalUnqualified()); 3724 3725 if (const VectorType *VT = dyn_cast<VectorType>(T)) 3726 T = VT->getElementType().getTypePtr(); 3727 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 3728 T = CT->getElementType().getTypePtr(); 3729 3730 // For enum types, use the known bit width of the enumerators. 3731 if (const EnumType *ET = dyn_cast<EnumType>(T)) { 3732 EnumDecl *Enum = ET->getDecl(); 3733 if (!Enum->isCompleteDefinition()) 3734 return IntRange(C.getIntWidth(QualType(T, 0)), false); 3735 3736 unsigned NumPositive = Enum->getNumPositiveBits(); 3737 unsigned NumNegative = Enum->getNumNegativeBits(); 3738 3739 return IntRange(std::max(NumPositive, NumNegative), NumNegative == 0); 3740 } 3741 3742 const BuiltinType *BT = cast<BuiltinType>(T); 3743 assert(BT->isInteger()); 3744 3745 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 3746 } 3747 3748 /// Returns the "target" range of a canonical integral type, i.e. 3749 /// the range of values expressible in the type. 3750 /// 3751 /// This matches forValueOfCanonicalType except that enums have the 3752 /// full range of their type, not the range of their enumerators. 3753 static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) { 3754 assert(T->isCanonicalUnqualified()); 3755 3756 if (const VectorType *VT = dyn_cast<VectorType>(T)) 3757 T = VT->getElementType().getTypePtr(); 3758 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 3759 T = CT->getElementType().getTypePtr(); 3760 if (const EnumType *ET = dyn_cast<EnumType>(T)) 3761 T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr(); 3762 3763 const BuiltinType *BT = cast<BuiltinType>(T); 3764 assert(BT->isInteger()); 3765 3766 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 3767 } 3768 3769 /// Returns the supremum of two ranges: i.e. their conservative merge. 3770 static IntRange join(IntRange L, IntRange R) { 3771 return IntRange(std::max(L.Width, R.Width), 3772 L.NonNegative && R.NonNegative); 3773 } 3774 3775 /// Returns the infinum of two ranges: i.e. their aggressive merge. 3776 static IntRange meet(IntRange L, IntRange R) { 3777 return IntRange(std::min(L.Width, R.Width), 3778 L.NonNegative || R.NonNegative); 3779 } 3780}; 3781 3782static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, 3783 unsigned MaxWidth) { 3784 if (value.isSigned() && value.isNegative()) 3785 return IntRange(value.getMinSignedBits(), false); 3786 3787 if (value.getBitWidth() > MaxWidth) 3788 value = value.trunc(MaxWidth); 3789 3790 // isNonNegative() just checks the sign bit without considering 3791 // signedness. 3792 return IntRange(value.getActiveBits(), true); 3793} 3794 3795static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty, 3796 unsigned MaxWidth) { 3797 if (result.isInt()) 3798 return GetValueRange(C, result.getInt(), MaxWidth); 3799 3800 if (result.isVector()) { 3801 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth); 3802 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) { 3803 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth); 3804 R = IntRange::join(R, El); 3805 } 3806 return R; 3807 } 3808 3809 if (result.isComplexInt()) { 3810 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth); 3811 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth); 3812 return IntRange::join(R, I); 3813 } 3814 3815 // This can happen with lossless casts to intptr_t of "based" lvalues. 3816 // Assume it might use arbitrary bits. 3817 // FIXME: The only reason we need to pass the type in here is to get 3818 // the sign right on this one case. It would be nice if APValue 3819 // preserved this. 3820 assert(result.isLValue() || result.isAddrLabelDiff()); 3821 return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType()); 3822} 3823 3824/// Pseudo-evaluate the given integer expression, estimating the 3825/// range of values it might take. 3826/// 3827/// \param MaxWidth - the width to which the value will be truncated 3828static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) { 3829 E = E->IgnoreParens(); 3830 3831 // Try a full evaluation first. 3832 Expr::EvalResult result; 3833 if (E->EvaluateAsRValue(result, C)) 3834 return GetValueRange(C, result.Val, E->getType(), MaxWidth); 3835 3836 // I think we only want to look through implicit casts here; if the 3837 // user has an explicit widening cast, we should treat the value as 3838 // being of the new, wider type. 3839 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) { 3840 if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue) 3841 return GetExprRange(C, CE->getSubExpr(), MaxWidth); 3842 3843 IntRange OutputTypeRange = IntRange::forValueOfType(C, CE->getType()); 3844 3845 bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast); 3846 3847 // Assume that non-integer casts can span the full range of the type. 3848 if (!isIntegerCast) 3849 return OutputTypeRange; 3850 3851 IntRange SubRange 3852 = GetExprRange(C, CE->getSubExpr(), 3853 std::min(MaxWidth, OutputTypeRange.Width)); 3854 3855 // Bail out if the subexpr's range is as wide as the cast type. 3856 if (SubRange.Width >= OutputTypeRange.Width) 3857 return OutputTypeRange; 3858 3859 // Otherwise, we take the smaller width, and we're non-negative if 3860 // either the output type or the subexpr is. 3861 return IntRange(SubRange.Width, 3862 SubRange.NonNegative || OutputTypeRange.NonNegative); 3863 } 3864 3865 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 3866 // If we can fold the condition, just take that operand. 3867 bool CondResult; 3868 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C)) 3869 return GetExprRange(C, CondResult ? CO->getTrueExpr() 3870 : CO->getFalseExpr(), 3871 MaxWidth); 3872 3873 // Otherwise, conservatively merge. 3874 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth); 3875 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth); 3876 return IntRange::join(L, R); 3877 } 3878 3879 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 3880 switch (BO->getOpcode()) { 3881 3882 // Boolean-valued operations are single-bit and positive. 3883 case BO_LAnd: 3884 case BO_LOr: 3885 case BO_LT: 3886 case BO_GT: 3887 case BO_LE: 3888 case BO_GE: 3889 case BO_EQ: 3890 case BO_NE: 3891 return IntRange::forBoolType(); 3892 3893 // The type of the assignments is the type of the LHS, so the RHS 3894 // is not necessarily the same type. 3895 case BO_MulAssign: 3896 case BO_DivAssign: 3897 case BO_RemAssign: 3898 case BO_AddAssign: 3899 case BO_SubAssign: 3900 case BO_XorAssign: 3901 case BO_OrAssign: 3902 // TODO: bitfields? 3903 return IntRange::forValueOfType(C, E->getType()); 3904 3905 // Simple assignments just pass through the RHS, which will have 3906 // been coerced to the LHS type. 3907 case BO_Assign: 3908 // TODO: bitfields? 3909 return GetExprRange(C, BO->getRHS(), MaxWidth); 3910 3911 // Operations with opaque sources are black-listed. 3912 case BO_PtrMemD: 3913 case BO_PtrMemI: 3914 return IntRange::forValueOfType(C, E->getType()); 3915 3916 // Bitwise-and uses the *infinum* of the two source ranges. 3917 case BO_And: 3918 case BO_AndAssign: 3919 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth), 3920 GetExprRange(C, BO->getRHS(), MaxWidth)); 3921 3922 // Left shift gets black-listed based on a judgement call. 3923 case BO_Shl: 3924 // ...except that we want to treat '1 << (blah)' as logically 3925 // positive. It's an important idiom. 3926 if (IntegerLiteral *I 3927 = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) { 3928 if (I->getValue() == 1) { 3929 IntRange R = IntRange::forValueOfType(C, E->getType()); 3930 return IntRange(R.Width, /*NonNegative*/ true); 3931 } 3932 } 3933 // fallthrough 3934 3935 case BO_ShlAssign: 3936 return IntRange::forValueOfType(C, E->getType()); 3937 3938 // Right shift by a constant can narrow its left argument. 3939 case BO_Shr: 3940 case BO_ShrAssign: { 3941 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 3942 3943 // If the shift amount is a positive constant, drop the width by 3944 // that much. 3945 llvm::APSInt shift; 3946 if (BO->getRHS()->isIntegerConstantExpr(shift, C) && 3947 shift.isNonNegative()) { 3948 unsigned zext = shift.getZExtValue(); 3949 if (zext >= L.Width) 3950 L.Width = (L.NonNegative ? 0 : 1); 3951 else 3952 L.Width -= zext; 3953 } 3954 3955 return L; 3956 } 3957 3958 // Comma acts as its right operand. 3959 case BO_Comma: 3960 return GetExprRange(C, BO->getRHS(), MaxWidth); 3961 3962 // Black-list pointer subtractions. 3963 case BO_Sub: 3964 if (BO->getLHS()->getType()->isPointerType()) 3965 return IntRange::forValueOfType(C, E->getType()); 3966 break; 3967 3968 // The width of a division result is mostly determined by the size 3969 // of the LHS. 3970 case BO_Div: { 3971 // Don't 'pre-truncate' the operands. 3972 unsigned opWidth = C.getIntWidth(E->getType()); 3973 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 3974 3975 // If the divisor is constant, use that. 3976 llvm::APSInt divisor; 3977 if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) { 3978 unsigned log2 = divisor.logBase2(); // floor(log_2(divisor)) 3979 if (log2 >= L.Width) 3980 L.Width = (L.NonNegative ? 0 : 1); 3981 else 3982 L.Width = std::min(L.Width - log2, MaxWidth); 3983 return L; 3984 } 3985 3986 // Otherwise, just use the LHS's width. 3987 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 3988 return IntRange(L.Width, L.NonNegative && R.NonNegative); 3989 } 3990 3991 // The result of a remainder can't be larger than the result of 3992 // either side. 3993 case BO_Rem: { 3994 // Don't 'pre-truncate' the operands. 3995 unsigned opWidth = C.getIntWidth(E->getType()); 3996 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 3997 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 3998 3999 IntRange meet = IntRange::meet(L, R); 4000 meet.Width = std::min(meet.Width, MaxWidth); 4001 return meet; 4002 } 4003 4004 // The default behavior is okay for these. 4005 case BO_Mul: 4006 case BO_Add: 4007 case BO_Xor: 4008 case BO_Or: 4009 break; 4010 } 4011 4012 // The default case is to treat the operation as if it were closed 4013 // on the narrowest type that encompasses both operands. 4014 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 4015 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth); 4016 return IntRange::join(L, R); 4017 } 4018 4019 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 4020 switch (UO->getOpcode()) { 4021 // Boolean-valued operations are white-listed. 4022 case UO_LNot: 4023 return IntRange::forBoolType(); 4024 4025 // Operations with opaque sources are black-listed. 4026 case UO_Deref: 4027 case UO_AddrOf: // should be impossible 4028 return IntRange::forValueOfType(C, E->getType()); 4029 4030 default: 4031 return GetExprRange(C, UO->getSubExpr(), MaxWidth); 4032 } 4033 } 4034 4035 if (dyn_cast<OffsetOfExpr>(E)) { 4036 IntRange::forValueOfType(C, E->getType()); 4037 } 4038 4039 if (FieldDecl *BitField = E->getBitField()) 4040 return IntRange(BitField->getBitWidthValue(C), 4041 BitField->getType()->isUnsignedIntegerOrEnumerationType()); 4042 4043 return IntRange::forValueOfType(C, E->getType()); 4044} 4045 4046static IntRange GetExprRange(ASTContext &C, Expr *E) { 4047 return GetExprRange(C, E, C.getIntWidth(E->getType())); 4048} 4049 4050/// Checks whether the given value, which currently has the given 4051/// source semantics, has the same value when coerced through the 4052/// target semantics. 4053static bool IsSameFloatAfterCast(const llvm::APFloat &value, 4054 const llvm::fltSemantics &Src, 4055 const llvm::fltSemantics &Tgt) { 4056 llvm::APFloat truncated = value; 4057 4058 bool ignored; 4059 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored); 4060 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored); 4061 4062 return truncated.bitwiseIsEqual(value); 4063} 4064 4065/// Checks whether the given value, which currently has the given 4066/// source semantics, has the same value when coerced through the 4067/// target semantics. 4068/// 4069/// The value might be a vector of floats (or a complex number). 4070static bool IsSameFloatAfterCast(const APValue &value, 4071 const llvm::fltSemantics &Src, 4072 const llvm::fltSemantics &Tgt) { 4073 if (value.isFloat()) 4074 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt); 4075 4076 if (value.isVector()) { 4077 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i) 4078 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt)) 4079 return false; 4080 return true; 4081 } 4082 4083 assert(value.isComplexFloat()); 4084 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) && 4085 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt)); 4086} 4087 4088static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC); 4089 4090static bool IsZero(Sema &S, Expr *E) { 4091 // Suppress cases where we are comparing against an enum constant. 4092 if (const DeclRefExpr *DR = 4093 dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts())) 4094 if (isa<EnumConstantDecl>(DR->getDecl())) 4095 return false; 4096 4097 // Suppress cases where the '0' value is expanded from a macro. 4098 if (E->getLocStart().isMacroID()) 4099 return false; 4100 4101 llvm::APSInt Value; 4102 return E->isIntegerConstantExpr(Value, S.Context) && Value == 0; 4103} 4104 4105static bool HasEnumType(Expr *E) { 4106 // Strip off implicit integral promotions. 4107 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 4108 if (ICE->getCastKind() != CK_IntegralCast && 4109 ICE->getCastKind() != CK_NoOp) 4110 break; 4111 E = ICE->getSubExpr(); 4112 } 4113 4114 return E->getType()->isEnumeralType(); 4115} 4116 4117static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) { 4118 BinaryOperatorKind op = E->getOpcode(); 4119 if (E->isValueDependent()) 4120 return; 4121 4122 if (op == BO_LT && IsZero(S, E->getRHS())) { 4123 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 4124 << "< 0" << "false" << HasEnumType(E->getLHS()) 4125 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4126 } else if (op == BO_GE && IsZero(S, E->getRHS())) { 4127 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 4128 << ">= 0" << "true" << HasEnumType(E->getLHS()) 4129 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4130 } else if (op == BO_GT && IsZero(S, E->getLHS())) { 4131 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 4132 << "0 >" << "false" << HasEnumType(E->getRHS()) 4133 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4134 } else if (op == BO_LE && IsZero(S, E->getLHS())) { 4135 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 4136 << "0 <=" << "true" << HasEnumType(E->getRHS()) 4137 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4138 } 4139} 4140 4141/// Analyze the operands of the given comparison. Implements the 4142/// fallback case from AnalyzeComparison. 4143static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) { 4144 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 4145 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 4146} 4147 4148/// \brief Implements -Wsign-compare. 4149/// 4150/// \param E the binary operator to check for warnings 4151static void AnalyzeComparison(Sema &S, BinaryOperator *E) { 4152 // The type the comparison is being performed in. 4153 QualType T = E->getLHS()->getType(); 4154 assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType()) 4155 && "comparison with mismatched types"); 4156 4157 // We don't do anything special if this isn't an unsigned integral 4158 // comparison: we're only interested in integral comparisons, and 4159 // signed comparisons only happen in cases we don't care to warn about. 4160 // 4161 // We also don't care about value-dependent expressions or expressions 4162 // whose result is a constant. 4163 if (!T->hasUnsignedIntegerRepresentation() 4164 || E->isValueDependent() || E->isIntegerConstantExpr(S.Context)) 4165 return AnalyzeImpConvsInComparison(S, E); 4166 4167 Expr *LHS = E->getLHS()->IgnoreParenImpCasts(); 4168 Expr *RHS = E->getRHS()->IgnoreParenImpCasts(); 4169 4170 // Check to see if one of the (unmodified) operands is of different 4171 // signedness. 4172 Expr *signedOperand, *unsignedOperand; 4173 if (LHS->getType()->hasSignedIntegerRepresentation()) { 4174 assert(!RHS->getType()->hasSignedIntegerRepresentation() && 4175 "unsigned comparison between two signed integer expressions?"); 4176 signedOperand = LHS; 4177 unsignedOperand = RHS; 4178 } else if (RHS->getType()->hasSignedIntegerRepresentation()) { 4179 signedOperand = RHS; 4180 unsignedOperand = LHS; 4181 } else { 4182 CheckTrivialUnsignedComparison(S, E); 4183 return AnalyzeImpConvsInComparison(S, E); 4184 } 4185 4186 // Otherwise, calculate the effective range of the signed operand. 4187 IntRange signedRange = GetExprRange(S.Context, signedOperand); 4188 4189 // Go ahead and analyze implicit conversions in the operands. Note 4190 // that we skip the implicit conversions on both sides. 4191 AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc()); 4192 AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc()); 4193 4194 // If the signed range is non-negative, -Wsign-compare won't fire, 4195 // but we should still check for comparisons which are always true 4196 // or false. 4197 if (signedRange.NonNegative) 4198 return CheckTrivialUnsignedComparison(S, E); 4199 4200 // For (in)equality comparisons, if the unsigned operand is a 4201 // constant which cannot collide with a overflowed signed operand, 4202 // then reinterpreting the signed operand as unsigned will not 4203 // change the result of the comparison. 4204 if (E->isEqualityOp()) { 4205 unsigned comparisonWidth = S.Context.getIntWidth(T); 4206 IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand); 4207 4208 // We should never be unable to prove that the unsigned operand is 4209 // non-negative. 4210 assert(unsignedRange.NonNegative && "unsigned range includes negative?"); 4211 4212 if (unsignedRange.Width < comparisonWidth) 4213 return; 4214 } 4215 4216 S.DiagRuntimeBehavior(E->getOperatorLoc(), E, 4217 S.PDiag(diag::warn_mixed_sign_comparison) 4218 << LHS->getType() << RHS->getType() 4219 << LHS->getSourceRange() << RHS->getSourceRange()); 4220} 4221 4222/// Analyzes an attempt to assign the given value to a bitfield. 4223/// 4224/// Returns true if there was something fishy about the attempt. 4225static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init, 4226 SourceLocation InitLoc) { 4227 assert(Bitfield->isBitField()); 4228 if (Bitfield->isInvalidDecl()) 4229 return false; 4230 4231 // White-list bool bitfields. 4232 if (Bitfield->getType()->isBooleanType()) 4233 return false; 4234 4235 // Ignore value- or type-dependent expressions. 4236 if (Bitfield->getBitWidth()->isValueDependent() || 4237 Bitfield->getBitWidth()->isTypeDependent() || 4238 Init->isValueDependent() || 4239 Init->isTypeDependent()) 4240 return false; 4241 4242 Expr *OriginalInit = Init->IgnoreParenImpCasts(); 4243 4244 llvm::APSInt Value; 4245 if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects)) 4246 return false; 4247 4248 unsigned OriginalWidth = Value.getBitWidth(); 4249 unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context); 4250 4251 if (OriginalWidth <= FieldWidth) 4252 return false; 4253 4254 // Compute the value which the bitfield will contain. 4255 llvm::APSInt TruncatedValue = Value.trunc(FieldWidth); 4256 TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType()); 4257 4258 // Check whether the stored value is equal to the original value. 4259 TruncatedValue = TruncatedValue.extend(OriginalWidth); 4260 if (llvm::APSInt::isSameValue(Value, TruncatedValue)) 4261 return false; 4262 4263 // Special-case bitfields of width 1: booleans are naturally 0/1, and 4264 // therefore don't strictly fit into a signed bitfield of width 1. 4265 if (FieldWidth == 1 && Value == 1) 4266 return false; 4267 4268 std::string PrettyValue = Value.toString(10); 4269 std::string PrettyTrunc = TruncatedValue.toString(10); 4270 4271 S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant) 4272 << PrettyValue << PrettyTrunc << OriginalInit->getType() 4273 << Init->getSourceRange(); 4274 4275 return true; 4276} 4277 4278/// Analyze the given simple or compound assignment for warning-worthy 4279/// operations. 4280static void AnalyzeAssignment(Sema &S, BinaryOperator *E) { 4281 // Just recurse on the LHS. 4282 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 4283 4284 // We want to recurse on the RHS as normal unless we're assigning to 4285 // a bitfield. 4286 if (FieldDecl *Bitfield = E->getLHS()->getBitField()) { 4287 if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(), 4288 E->getOperatorLoc())) { 4289 // Recurse, ignoring any implicit conversions on the RHS. 4290 return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(), 4291 E->getOperatorLoc()); 4292 } 4293 } 4294 4295 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 4296} 4297 4298/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 4299static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T, 4300 SourceLocation CContext, unsigned diag, 4301 bool pruneControlFlow = false) { 4302 if (pruneControlFlow) { 4303 S.DiagRuntimeBehavior(E->getExprLoc(), E, 4304 S.PDiag(diag) 4305 << SourceType << T << E->getSourceRange() 4306 << SourceRange(CContext)); 4307 return; 4308 } 4309 S.Diag(E->getExprLoc(), diag) 4310 << SourceType << T << E->getSourceRange() << SourceRange(CContext); 4311} 4312 4313/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 4314static void DiagnoseImpCast(Sema &S, Expr *E, QualType T, 4315 SourceLocation CContext, unsigned diag, 4316 bool pruneControlFlow = false) { 4317 DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow); 4318} 4319 4320/// Diagnose an implicit cast from a literal expression. Does not warn when the 4321/// cast wouldn't lose information. 4322void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T, 4323 SourceLocation CContext) { 4324 // Try to convert the literal exactly to an integer. If we can, don't warn. 4325 bool isExact = false; 4326 const llvm::APFloat &Value = FL->getValue(); 4327 llvm::APSInt IntegerValue(S.Context.getIntWidth(T), 4328 T->hasUnsignedIntegerRepresentation()); 4329 if (Value.convertToInteger(IntegerValue, 4330 llvm::APFloat::rmTowardZero, &isExact) 4331 == llvm::APFloat::opOK && isExact) 4332 return; 4333 4334 SmallString<16> PrettySourceValue; 4335 Value.toString(PrettySourceValue); 4336 SmallString<16> PrettyTargetValue; 4337 if (T->isSpecificBuiltinType(BuiltinType::Bool)) 4338 PrettyTargetValue = IntegerValue == 0 ? "false" : "true"; 4339 else 4340 IntegerValue.toString(PrettyTargetValue); 4341 4342 S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer) 4343 << FL->getType() << T.getUnqualifiedType() << PrettySourceValue 4344 << PrettyTargetValue << FL->getSourceRange() << SourceRange(CContext); 4345} 4346 4347std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) { 4348 if (!Range.Width) return "0"; 4349 4350 llvm::APSInt ValueInRange = Value; 4351 ValueInRange.setIsSigned(!Range.NonNegative); 4352 ValueInRange = ValueInRange.trunc(Range.Width); 4353 return ValueInRange.toString(10); 4354} 4355 4356void CheckImplicitConversion(Sema &S, Expr *E, QualType T, 4357 SourceLocation CC, bool *ICContext = 0) { 4358 if (E->isTypeDependent() || E->isValueDependent()) return; 4359 4360 const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr(); 4361 const Type *Target = S.Context.getCanonicalType(T).getTypePtr(); 4362 if (Source == Target) return; 4363 if (Target->isDependentType()) return; 4364 4365 // If the conversion context location is invalid don't complain. We also 4366 // don't want to emit a warning if the issue occurs from the expansion of 4367 // a system macro. The problem is that 'getSpellingLoc()' is slow, so we 4368 // delay this check as long as possible. Once we detect we are in that 4369 // scenario, we just return. 4370 if (CC.isInvalid()) 4371 return; 4372 4373 // Diagnose implicit casts to bool. 4374 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) { 4375 if (isa<StringLiteral>(E)) 4376 // Warn on string literal to bool. Checks for string literals in logical 4377 // expressions, for instances, assert(0 && "error here"), is prevented 4378 // by a check in AnalyzeImplicitConversions(). 4379 return DiagnoseImpCast(S, E, T, CC, 4380 diag::warn_impcast_string_literal_to_bool); 4381 if (Source->isFunctionType()) { 4382 // Warn on function to bool. Checks free functions and static member 4383 // functions. Weakly imported functions are excluded from the check, 4384 // since it's common to test their value to check whether the linker 4385 // found a definition for them. 4386 ValueDecl *D = 0; 4387 if (DeclRefExpr* R = dyn_cast<DeclRefExpr>(E)) { 4388 D = R->getDecl(); 4389 } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) { 4390 D = M->getMemberDecl(); 4391 } 4392 4393 if (D && !D->isWeak()) { 4394 if (FunctionDecl* F = dyn_cast<FunctionDecl>(D)) { 4395 S.Diag(E->getExprLoc(), diag::warn_impcast_function_to_bool) 4396 << F << E->getSourceRange() << SourceRange(CC); 4397 S.Diag(E->getExprLoc(), diag::note_function_to_bool_silence) 4398 << FixItHint::CreateInsertion(E->getExprLoc(), "&"); 4399 QualType ReturnType; 4400 UnresolvedSet<4> NonTemplateOverloads; 4401 S.isExprCallable(*E, ReturnType, NonTemplateOverloads); 4402 if (!ReturnType.isNull() 4403 && ReturnType->isSpecificBuiltinType(BuiltinType::Bool)) 4404 S.Diag(E->getExprLoc(), diag::note_function_to_bool_call) 4405 << FixItHint::CreateInsertion( 4406 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()), "()"); 4407 return; 4408 } 4409 } 4410 } 4411 } 4412 4413 // Strip vector types. 4414 if (isa<VectorType>(Source)) { 4415 if (!isa<VectorType>(Target)) { 4416 if (S.SourceMgr.isInSystemMacro(CC)) 4417 return; 4418 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar); 4419 } 4420 4421 // If the vector cast is cast between two vectors of the same size, it is 4422 // a bitcast, not a conversion. 4423 if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target)) 4424 return; 4425 4426 Source = cast<VectorType>(Source)->getElementType().getTypePtr(); 4427 Target = cast<VectorType>(Target)->getElementType().getTypePtr(); 4428 } 4429 4430 // Strip complex types. 4431 if (isa<ComplexType>(Source)) { 4432 if (!isa<ComplexType>(Target)) { 4433 if (S.SourceMgr.isInSystemMacro(CC)) 4434 return; 4435 4436 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar); 4437 } 4438 4439 Source = cast<ComplexType>(Source)->getElementType().getTypePtr(); 4440 Target = cast<ComplexType>(Target)->getElementType().getTypePtr(); 4441 } 4442 4443 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source); 4444 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target); 4445 4446 // If the source is floating point... 4447 if (SourceBT && SourceBT->isFloatingPoint()) { 4448 // ...and the target is floating point... 4449 if (TargetBT && TargetBT->isFloatingPoint()) { 4450 // ...then warn if we're dropping FP rank. 4451 4452 // Builtin FP kinds are ordered by increasing FP rank. 4453 if (SourceBT->getKind() > TargetBT->getKind()) { 4454 // Don't warn about float constants that are precisely 4455 // representable in the target type. 4456 Expr::EvalResult result; 4457 if (E->EvaluateAsRValue(result, S.Context)) { 4458 // Value might be a float, a float vector, or a float complex. 4459 if (IsSameFloatAfterCast(result.Val, 4460 S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)), 4461 S.Context.getFloatTypeSemantics(QualType(SourceBT, 0)))) 4462 return; 4463 } 4464 4465 if (S.SourceMgr.isInSystemMacro(CC)) 4466 return; 4467 4468 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision); 4469 } 4470 return; 4471 } 4472 4473 // If the target is integral, always warn. 4474 if (TargetBT && TargetBT->isInteger()) { 4475 if (S.SourceMgr.isInSystemMacro(CC)) 4476 return; 4477 4478 Expr *InnerE = E->IgnoreParenImpCasts(); 4479 // We also want to warn on, e.g., "int i = -1.234" 4480 if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE)) 4481 if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus) 4482 InnerE = UOp->getSubExpr()->IgnoreParenImpCasts(); 4483 4484 if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) { 4485 DiagnoseFloatingLiteralImpCast(S, FL, T, CC); 4486 } else { 4487 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer); 4488 } 4489 } 4490 4491 return; 4492 } 4493 4494 if ((E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull) 4495 == Expr::NPCK_GNUNull) && !Target->isAnyPointerType() 4496 && !Target->isBlockPointerType() && !Target->isMemberPointerType()) { 4497 SourceLocation Loc = E->getSourceRange().getBegin(); 4498 if (Loc.isMacroID()) 4499 Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first; 4500 if (!Loc.isMacroID() || CC.isMacroID()) 4501 S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer) 4502 << T << clang::SourceRange(CC) 4503 << FixItHint::CreateReplacement(Loc, S.getFixItZeroLiteralForType(T)); 4504 } 4505 4506 if (!Source->isIntegerType() || !Target->isIntegerType()) 4507 return; 4508 4509 // TODO: remove this early return once the false positives for constant->bool 4510 // in templates, macros, etc, are reduced or removed. 4511 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) 4512 return; 4513 4514 IntRange SourceRange = GetExprRange(S.Context, E); 4515 IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target); 4516 4517 if (SourceRange.Width > TargetRange.Width) { 4518 // If the source is a constant, use a default-on diagnostic. 4519 // TODO: this should happen for bitfield stores, too. 4520 llvm::APSInt Value(32); 4521 if (E->isIntegerConstantExpr(Value, S.Context)) { 4522 if (S.SourceMgr.isInSystemMacro(CC)) 4523 return; 4524 4525 std::string PrettySourceValue = Value.toString(10); 4526 std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange); 4527 4528 S.DiagRuntimeBehavior(E->getExprLoc(), E, 4529 S.PDiag(diag::warn_impcast_integer_precision_constant) 4530 << PrettySourceValue << PrettyTargetValue 4531 << E->getType() << T << E->getSourceRange() 4532 << clang::SourceRange(CC)); 4533 return; 4534 } 4535 4536 // People want to build with -Wshorten-64-to-32 and not -Wconversion. 4537 if (S.SourceMgr.isInSystemMacro(CC)) 4538 return; 4539 4540 if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64) 4541 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32, 4542 /* pruneControlFlow */ true); 4543 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision); 4544 } 4545 4546 if ((TargetRange.NonNegative && !SourceRange.NonNegative) || 4547 (!TargetRange.NonNegative && SourceRange.NonNegative && 4548 SourceRange.Width == TargetRange.Width)) { 4549 4550 if (S.SourceMgr.isInSystemMacro(CC)) 4551 return; 4552 4553 unsigned DiagID = diag::warn_impcast_integer_sign; 4554 4555 // Traditionally, gcc has warned about this under -Wsign-compare. 4556 // We also want to warn about it in -Wconversion. 4557 // So if -Wconversion is off, use a completely identical diagnostic 4558 // in the sign-compare group. 4559 // The conditional-checking code will 4560 if (ICContext) { 4561 DiagID = diag::warn_impcast_integer_sign_conditional; 4562 *ICContext = true; 4563 } 4564 4565 return DiagnoseImpCast(S, E, T, CC, DiagID); 4566 } 4567 4568 // Diagnose conversions between different enumeration types. 4569 // In C, we pretend that the type of an EnumConstantDecl is its enumeration 4570 // type, to give us better diagnostics. 4571 QualType SourceType = E->getType(); 4572 if (!S.getLangOpts().CPlusPlus) { 4573 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 4574 if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) { 4575 EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext()); 4576 SourceType = S.Context.getTypeDeclType(Enum); 4577 Source = S.Context.getCanonicalType(SourceType).getTypePtr(); 4578 } 4579 } 4580 4581 if (const EnumType *SourceEnum = Source->getAs<EnumType>()) 4582 if (const EnumType *TargetEnum = Target->getAs<EnumType>()) 4583 if ((SourceEnum->getDecl()->getIdentifier() || 4584 SourceEnum->getDecl()->getTypedefNameForAnonDecl()) && 4585 (TargetEnum->getDecl()->getIdentifier() || 4586 TargetEnum->getDecl()->getTypedefNameForAnonDecl()) && 4587 SourceEnum != TargetEnum) { 4588 if (S.SourceMgr.isInSystemMacro(CC)) 4589 return; 4590 4591 return DiagnoseImpCast(S, E, SourceType, T, CC, 4592 diag::warn_impcast_different_enum_types); 4593 } 4594 4595 return; 4596} 4597 4598void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 4599 SourceLocation CC, QualType T); 4600 4601void CheckConditionalOperand(Sema &S, Expr *E, QualType T, 4602 SourceLocation CC, bool &ICContext) { 4603 E = E->IgnoreParenImpCasts(); 4604 4605 if (isa<ConditionalOperator>(E)) 4606 return CheckConditionalOperator(S, cast<ConditionalOperator>(E), CC, T); 4607 4608 AnalyzeImplicitConversions(S, E, CC); 4609 if (E->getType() != T) 4610 return CheckImplicitConversion(S, E, T, CC, &ICContext); 4611 return; 4612} 4613 4614void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 4615 SourceLocation CC, QualType T) { 4616 AnalyzeImplicitConversions(S, E->getCond(), CC); 4617 4618 bool Suspicious = false; 4619 CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious); 4620 CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious); 4621 4622 // If -Wconversion would have warned about either of the candidates 4623 // for a signedness conversion to the context type... 4624 if (!Suspicious) return; 4625 4626 // ...but it's currently ignored... 4627 if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional, 4628 CC)) 4629 return; 4630 4631 // ...then check whether it would have warned about either of the 4632 // candidates for a signedness conversion to the condition type. 4633 if (E->getType() == T) return; 4634 4635 Suspicious = false; 4636 CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(), 4637 E->getType(), CC, &Suspicious); 4638 if (!Suspicious) 4639 CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(), 4640 E->getType(), CC, &Suspicious); 4641} 4642 4643/// AnalyzeImplicitConversions - Find and report any interesting 4644/// implicit conversions in the given expression. There are a couple 4645/// of competing diagnostics here, -Wconversion and -Wsign-compare. 4646void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) { 4647 QualType T = OrigE->getType(); 4648 Expr *E = OrigE->IgnoreParenImpCasts(); 4649 4650 if (E->isTypeDependent() || E->isValueDependent()) 4651 return; 4652 4653 // For conditional operators, we analyze the arguments as if they 4654 // were being fed directly into the output. 4655 if (isa<ConditionalOperator>(E)) { 4656 ConditionalOperator *CO = cast<ConditionalOperator>(E); 4657 CheckConditionalOperator(S, CO, CC, T); 4658 return; 4659 } 4660 4661 // Go ahead and check any implicit conversions we might have skipped. 4662 // The non-canonical typecheck is just an optimization; 4663 // CheckImplicitConversion will filter out dead implicit conversions. 4664 if (E->getType() != T) 4665 CheckImplicitConversion(S, E, T, CC); 4666 4667 // Now continue drilling into this expression. 4668 4669 // Skip past explicit casts. 4670 if (isa<ExplicitCastExpr>(E)) { 4671 E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts(); 4672 return AnalyzeImplicitConversions(S, E, CC); 4673 } 4674 4675 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 4676 // Do a somewhat different check with comparison operators. 4677 if (BO->isComparisonOp()) 4678 return AnalyzeComparison(S, BO); 4679 4680 // And with simple assignments. 4681 if (BO->getOpcode() == BO_Assign) 4682 return AnalyzeAssignment(S, BO); 4683 } 4684 4685 // These break the otherwise-useful invariant below. Fortunately, 4686 // we don't really need to recurse into them, because any internal 4687 // expressions should have been analyzed already when they were 4688 // built into statements. 4689 if (isa<StmtExpr>(E)) return; 4690 4691 // Don't descend into unevaluated contexts. 4692 if (isa<UnaryExprOrTypeTraitExpr>(E)) return; 4693 4694 // Now just recurse over the expression's children. 4695 CC = E->getExprLoc(); 4696 BinaryOperator *BO = dyn_cast<BinaryOperator>(E); 4697 bool IsLogicalOperator = BO && BO->isLogicalOp(); 4698 for (Stmt::child_range I = E->children(); I; ++I) { 4699 Expr *ChildExpr = dyn_cast_or_null<Expr>(*I); 4700 if (!ChildExpr) 4701 continue; 4702 4703 if (IsLogicalOperator && 4704 isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts())) 4705 // Ignore checking string literals that are in logical operators. 4706 continue; 4707 AnalyzeImplicitConversions(S, ChildExpr, CC); 4708 } 4709} 4710 4711} // end anonymous namespace 4712 4713/// Diagnoses "dangerous" implicit conversions within the given 4714/// expression (which is a full expression). Implements -Wconversion 4715/// and -Wsign-compare. 4716/// 4717/// \param CC the "context" location of the implicit conversion, i.e. 4718/// the most location of the syntactic entity requiring the implicit 4719/// conversion 4720void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) { 4721 // Don't diagnose in unevaluated contexts. 4722 if (isUnevaluatedContext()) 4723 return; 4724 4725 // Don't diagnose for value- or type-dependent expressions. 4726 if (E->isTypeDependent() || E->isValueDependent()) 4727 return; 4728 4729 // Check for array bounds violations in cases where the check isn't triggered 4730 // elsewhere for other Expr types (like BinaryOperators), e.g. when an 4731 // ArraySubscriptExpr is on the RHS of a variable initialization. 4732 CheckArrayAccess(E); 4733 4734 // This is not the right CC for (e.g.) a variable initialization. 4735 AnalyzeImplicitConversions(*this, E, CC); 4736} 4737 4738void Sema::CheckBitFieldInitialization(SourceLocation InitLoc, 4739 FieldDecl *BitField, 4740 Expr *Init) { 4741 (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc); 4742} 4743 4744/// CheckParmsForFunctionDef - Check that the parameters of the given 4745/// function are appropriate for the definition of a function. This 4746/// takes care of any checks that cannot be performed on the 4747/// declaration itself, e.g., that the types of each of the function 4748/// parameters are complete. 4749bool Sema::CheckParmsForFunctionDef(ParmVarDecl **P, ParmVarDecl **PEnd, 4750 bool CheckParameterNames) { 4751 bool HasInvalidParm = false; 4752 for (; P != PEnd; ++P) { 4753 ParmVarDecl *Param = *P; 4754 4755 // C99 6.7.5.3p4: the parameters in a parameter type list in a 4756 // function declarator that is part of a function definition of 4757 // that function shall not have incomplete type. 4758 // 4759 // This is also C++ [dcl.fct]p6. 4760 if (!Param->isInvalidDecl() && 4761 RequireCompleteType(Param->getLocation(), Param->getType(), 4762 diag::err_typecheck_decl_incomplete_type)) { 4763 Param->setInvalidDecl(); 4764 HasInvalidParm = true; 4765 } 4766 4767 // C99 6.9.1p5: If the declarator includes a parameter type list, the 4768 // declaration of each parameter shall include an identifier. 4769 if (CheckParameterNames && 4770 Param->getIdentifier() == 0 && 4771 !Param->isImplicit() && 4772 !getLangOpts().CPlusPlus) 4773 Diag(Param->getLocation(), diag::err_parameter_name_omitted); 4774 4775 // C99 6.7.5.3p12: 4776 // If the function declarator is not part of a definition of that 4777 // function, parameters may have incomplete type and may use the [*] 4778 // notation in their sequences of declarator specifiers to specify 4779 // variable length array types. 4780 QualType PType = Param->getOriginalType(); 4781 if (const ArrayType *AT = Context.getAsArrayType(PType)) { 4782 if (AT->getSizeModifier() == ArrayType::Star) { 4783 // FIXME: This diagnosic should point the '[*]' if source-location 4784 // information is added for it. 4785 Diag(Param->getLocation(), diag::err_array_star_in_function_definition); 4786 } 4787 } 4788 } 4789 4790 return HasInvalidParm; 4791} 4792 4793/// CheckCastAlign - Implements -Wcast-align, which warns when a 4794/// pointer cast increases the alignment requirements. 4795void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) { 4796 // This is actually a lot of work to potentially be doing on every 4797 // cast; don't do it if we're ignoring -Wcast_align (as is the default). 4798 if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align, 4799 TRange.getBegin()) 4800 == DiagnosticsEngine::Ignored) 4801 return; 4802 4803 // Ignore dependent types. 4804 if (T->isDependentType() || Op->getType()->isDependentType()) 4805 return; 4806 4807 // Require that the destination be a pointer type. 4808 const PointerType *DestPtr = T->getAs<PointerType>(); 4809 if (!DestPtr) return; 4810 4811 // If the destination has alignment 1, we're done. 4812 QualType DestPointee = DestPtr->getPointeeType(); 4813 if (DestPointee->isIncompleteType()) return; 4814 CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee); 4815 if (DestAlign.isOne()) return; 4816 4817 // Require that the source be a pointer type. 4818 const PointerType *SrcPtr = Op->getType()->getAs<PointerType>(); 4819 if (!SrcPtr) return; 4820 QualType SrcPointee = SrcPtr->getPointeeType(); 4821 4822 // Whitelist casts from cv void*. We already implicitly 4823 // whitelisted casts to cv void*, since they have alignment 1. 4824 // Also whitelist casts involving incomplete types, which implicitly 4825 // includes 'void'. 4826 if (SrcPointee->isIncompleteType()) return; 4827 4828 CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee); 4829 if (SrcAlign >= DestAlign) return; 4830 4831 Diag(TRange.getBegin(), diag::warn_cast_align) 4832 << Op->getType() << T 4833 << static_cast<unsigned>(SrcAlign.getQuantity()) 4834 << static_cast<unsigned>(DestAlign.getQuantity()) 4835 << TRange << Op->getSourceRange(); 4836} 4837 4838static const Type* getElementType(const Expr *BaseExpr) { 4839 const Type* EltType = BaseExpr->getType().getTypePtr(); 4840 if (EltType->isAnyPointerType()) 4841 return EltType->getPointeeType().getTypePtr(); 4842 else if (EltType->isArrayType()) 4843 return EltType->getBaseElementTypeUnsafe(); 4844 return EltType; 4845} 4846 4847/// \brief Check whether this array fits the idiom of a size-one tail padded 4848/// array member of a struct. 4849/// 4850/// We avoid emitting out-of-bounds access warnings for such arrays as they are 4851/// commonly used to emulate flexible arrays in C89 code. 4852static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size, 4853 const NamedDecl *ND) { 4854 if (Size != 1 || !ND) return false; 4855 4856 const FieldDecl *FD = dyn_cast<FieldDecl>(ND); 4857 if (!FD) return false; 4858 4859 // Don't consider sizes resulting from macro expansions or template argument 4860 // substitution to form C89 tail-padded arrays. 4861 4862 TypeSourceInfo *TInfo = FD->getTypeSourceInfo(); 4863 while (TInfo) { 4864 TypeLoc TL = TInfo->getTypeLoc(); 4865 // Look through typedefs. 4866 const TypedefTypeLoc *TTL = dyn_cast<TypedefTypeLoc>(&TL); 4867 if (TTL) { 4868 const TypedefNameDecl *TDL = TTL->getTypedefNameDecl(); 4869 TInfo = TDL->getTypeSourceInfo(); 4870 continue; 4871 } 4872 ConstantArrayTypeLoc CTL = cast<ConstantArrayTypeLoc>(TL); 4873 const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr()); 4874 if (!SizeExpr || SizeExpr->getExprLoc().isMacroID()) 4875 return false; 4876 break; 4877 } 4878 4879 const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext()); 4880 if (!RD) return false; 4881 if (RD->isUnion()) return false; 4882 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) { 4883 if (!CRD->isStandardLayout()) return false; 4884 } 4885 4886 // See if this is the last field decl in the record. 4887 const Decl *D = FD; 4888 while ((D = D->getNextDeclInContext())) 4889 if (isa<FieldDecl>(D)) 4890 return false; 4891 return true; 4892} 4893 4894void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr, 4895 const ArraySubscriptExpr *ASE, 4896 bool AllowOnePastEnd, bool IndexNegated) { 4897 IndexExpr = IndexExpr->IgnoreParenImpCasts(); 4898 if (IndexExpr->isValueDependent()) 4899 return; 4900 4901 const Type *EffectiveType = getElementType(BaseExpr); 4902 BaseExpr = BaseExpr->IgnoreParenCasts(); 4903 const ConstantArrayType *ArrayTy = 4904 Context.getAsConstantArrayType(BaseExpr->getType()); 4905 if (!ArrayTy) 4906 return; 4907 4908 llvm::APSInt index; 4909 if (!IndexExpr->EvaluateAsInt(index, Context)) 4910 return; 4911 if (IndexNegated) 4912 index = -index; 4913 4914 const NamedDecl *ND = NULL; 4915 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 4916 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 4917 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 4918 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 4919 4920 if (index.isUnsigned() || !index.isNegative()) { 4921 llvm::APInt size = ArrayTy->getSize(); 4922 if (!size.isStrictlyPositive()) 4923 return; 4924 4925 const Type* BaseType = getElementType(BaseExpr); 4926 if (BaseType != EffectiveType) { 4927 // Make sure we're comparing apples to apples when comparing index to size 4928 uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType); 4929 uint64_t array_typesize = Context.getTypeSize(BaseType); 4930 // Handle ptrarith_typesize being zero, such as when casting to void* 4931 if (!ptrarith_typesize) ptrarith_typesize = 1; 4932 if (ptrarith_typesize != array_typesize) { 4933 // There's a cast to a different size type involved 4934 uint64_t ratio = array_typesize / ptrarith_typesize; 4935 // TODO: Be smarter about handling cases where array_typesize is not a 4936 // multiple of ptrarith_typesize 4937 if (ptrarith_typesize * ratio == array_typesize) 4938 size *= llvm::APInt(size.getBitWidth(), ratio); 4939 } 4940 } 4941 4942 if (size.getBitWidth() > index.getBitWidth()) 4943 index = index.zext(size.getBitWidth()); 4944 else if (size.getBitWidth() < index.getBitWidth()) 4945 size = size.zext(index.getBitWidth()); 4946 4947 // For array subscripting the index must be less than size, but for pointer 4948 // arithmetic also allow the index (offset) to be equal to size since 4949 // computing the next address after the end of the array is legal and 4950 // commonly done e.g. in C++ iterators and range-based for loops. 4951 if (AllowOnePastEnd ? index.ule(size) : index.ult(size)) 4952 return; 4953 4954 // Also don't warn for arrays of size 1 which are members of some 4955 // structure. These are often used to approximate flexible arrays in C89 4956 // code. 4957 if (IsTailPaddedMemberArray(*this, size, ND)) 4958 return; 4959 4960 // Suppress the warning if the subscript expression (as identified by the 4961 // ']' location) and the index expression are both from macro expansions 4962 // within a system header. 4963 if (ASE) { 4964 SourceLocation RBracketLoc = SourceMgr.getSpellingLoc( 4965 ASE->getRBracketLoc()); 4966 if (SourceMgr.isInSystemHeader(RBracketLoc)) { 4967 SourceLocation IndexLoc = SourceMgr.getSpellingLoc( 4968 IndexExpr->getLocStart()); 4969 if (SourceMgr.isFromSameFile(RBracketLoc, IndexLoc)) 4970 return; 4971 } 4972 } 4973 4974 unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds; 4975 if (ASE) 4976 DiagID = diag::warn_array_index_exceeds_bounds; 4977 4978 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 4979 PDiag(DiagID) << index.toString(10, true) 4980 << size.toString(10, true) 4981 << (unsigned)size.getLimitedValue(~0U) 4982 << IndexExpr->getSourceRange()); 4983 } else { 4984 unsigned DiagID = diag::warn_array_index_precedes_bounds; 4985 if (!ASE) { 4986 DiagID = diag::warn_ptr_arith_precedes_bounds; 4987 if (index.isNegative()) index = -index; 4988 } 4989 4990 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 4991 PDiag(DiagID) << index.toString(10, true) 4992 << IndexExpr->getSourceRange()); 4993 } 4994 4995 if (!ND) { 4996 // Try harder to find a NamedDecl to point at in the note. 4997 while (const ArraySubscriptExpr *ASE = 4998 dyn_cast<ArraySubscriptExpr>(BaseExpr)) 4999 BaseExpr = ASE->getBase()->IgnoreParenCasts(); 5000 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 5001 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 5002 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 5003 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 5004 } 5005 5006 if (ND) 5007 DiagRuntimeBehavior(ND->getLocStart(), BaseExpr, 5008 PDiag(diag::note_array_index_out_of_bounds) 5009 << ND->getDeclName()); 5010} 5011 5012void Sema::CheckArrayAccess(const Expr *expr) { 5013 int AllowOnePastEnd = 0; 5014 while (expr) { 5015 expr = expr->IgnoreParenImpCasts(); 5016 switch (expr->getStmtClass()) { 5017 case Stmt::ArraySubscriptExprClass: { 5018 const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr); 5019 CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE, 5020 AllowOnePastEnd > 0); 5021 return; 5022 } 5023 case Stmt::UnaryOperatorClass: { 5024 // Only unwrap the * and & unary operators 5025 const UnaryOperator *UO = cast<UnaryOperator>(expr); 5026 expr = UO->getSubExpr(); 5027 switch (UO->getOpcode()) { 5028 case UO_AddrOf: 5029 AllowOnePastEnd++; 5030 break; 5031 case UO_Deref: 5032 AllowOnePastEnd--; 5033 break; 5034 default: 5035 return; 5036 } 5037 break; 5038 } 5039 case Stmt::ConditionalOperatorClass: { 5040 const ConditionalOperator *cond = cast<ConditionalOperator>(expr); 5041 if (const Expr *lhs = cond->getLHS()) 5042 CheckArrayAccess(lhs); 5043 if (const Expr *rhs = cond->getRHS()) 5044 CheckArrayAccess(rhs); 5045 return; 5046 } 5047 default: 5048 return; 5049 } 5050 } 5051} 5052 5053//===--- CHECK: Objective-C retain cycles ----------------------------------// 5054 5055namespace { 5056 struct RetainCycleOwner { 5057 RetainCycleOwner() : Variable(0), Indirect(false) {} 5058 VarDecl *Variable; 5059 SourceRange Range; 5060 SourceLocation Loc; 5061 bool Indirect; 5062 5063 void setLocsFrom(Expr *e) { 5064 Loc = e->getExprLoc(); 5065 Range = e->getSourceRange(); 5066 } 5067 }; 5068} 5069 5070/// Consider whether capturing the given variable can possibly lead to 5071/// a retain cycle. 5072static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) { 5073 // In ARC, it's captured strongly iff the variable has __strong 5074 // lifetime. In MRR, it's captured strongly if the variable is 5075 // __block and has an appropriate type. 5076 if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 5077 return false; 5078 5079 owner.Variable = var; 5080 owner.setLocsFrom(ref); 5081 return true; 5082} 5083 5084static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) { 5085 while (true) { 5086 e = e->IgnoreParens(); 5087 if (CastExpr *cast = dyn_cast<CastExpr>(e)) { 5088 switch (cast->getCastKind()) { 5089 case CK_BitCast: 5090 case CK_LValueBitCast: 5091 case CK_LValueToRValue: 5092 case CK_ARCReclaimReturnedObject: 5093 e = cast->getSubExpr(); 5094 continue; 5095 5096 default: 5097 return false; 5098 } 5099 } 5100 5101 if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) { 5102 ObjCIvarDecl *ivar = ref->getDecl(); 5103 if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 5104 return false; 5105 5106 // Try to find a retain cycle in the base. 5107 if (!findRetainCycleOwner(S, ref->getBase(), owner)) 5108 return false; 5109 5110 if (ref->isFreeIvar()) owner.setLocsFrom(ref); 5111 owner.Indirect = true; 5112 return true; 5113 } 5114 5115 if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) { 5116 VarDecl *var = dyn_cast<VarDecl>(ref->getDecl()); 5117 if (!var) return false; 5118 return considerVariable(var, ref, owner); 5119 } 5120 5121 if (MemberExpr *member = dyn_cast<MemberExpr>(e)) { 5122 if (member->isArrow()) return false; 5123 5124 // Don't count this as an indirect ownership. 5125 e = member->getBase(); 5126 continue; 5127 } 5128 5129 if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) { 5130 // Only pay attention to pseudo-objects on property references. 5131 ObjCPropertyRefExpr *pre 5132 = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm() 5133 ->IgnoreParens()); 5134 if (!pre) return false; 5135 if (pre->isImplicitProperty()) return false; 5136 ObjCPropertyDecl *property = pre->getExplicitProperty(); 5137 if (!property->isRetaining() && 5138 !(property->getPropertyIvarDecl() && 5139 property->getPropertyIvarDecl()->getType() 5140 .getObjCLifetime() == Qualifiers::OCL_Strong)) 5141 return false; 5142 5143 owner.Indirect = true; 5144 if (pre->isSuperReceiver()) { 5145 owner.Variable = S.getCurMethodDecl()->getSelfDecl(); 5146 if (!owner.Variable) 5147 return false; 5148 owner.Loc = pre->getLocation(); 5149 owner.Range = pre->getSourceRange(); 5150 return true; 5151 } 5152 e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase()) 5153 ->getSourceExpr()); 5154 continue; 5155 } 5156 5157 // Array ivars? 5158 5159 return false; 5160 } 5161} 5162 5163namespace { 5164 struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> { 5165 FindCaptureVisitor(ASTContext &Context, VarDecl *variable) 5166 : EvaluatedExprVisitor<FindCaptureVisitor>(Context), 5167 Variable(variable), Capturer(0) {} 5168 5169 VarDecl *Variable; 5170 Expr *Capturer; 5171 5172 void VisitDeclRefExpr(DeclRefExpr *ref) { 5173 if (ref->getDecl() == Variable && !Capturer) 5174 Capturer = ref; 5175 } 5176 5177 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) { 5178 if (Capturer) return; 5179 Visit(ref->getBase()); 5180 if (Capturer && ref->isFreeIvar()) 5181 Capturer = ref; 5182 } 5183 5184 void VisitBlockExpr(BlockExpr *block) { 5185 // Look inside nested blocks 5186 if (block->getBlockDecl()->capturesVariable(Variable)) 5187 Visit(block->getBlockDecl()->getBody()); 5188 } 5189 }; 5190} 5191 5192/// Check whether the given argument is a block which captures a 5193/// variable. 5194static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) { 5195 assert(owner.Variable && owner.Loc.isValid()); 5196 5197 e = e->IgnoreParenCasts(); 5198 BlockExpr *block = dyn_cast<BlockExpr>(e); 5199 if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable)) 5200 return 0; 5201 5202 FindCaptureVisitor visitor(S.Context, owner.Variable); 5203 visitor.Visit(block->getBlockDecl()->getBody()); 5204 return visitor.Capturer; 5205} 5206 5207static void diagnoseRetainCycle(Sema &S, Expr *capturer, 5208 RetainCycleOwner &owner) { 5209 assert(capturer); 5210 assert(owner.Variable && owner.Loc.isValid()); 5211 5212 S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle) 5213 << owner.Variable << capturer->getSourceRange(); 5214 S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner) 5215 << owner.Indirect << owner.Range; 5216} 5217 5218/// Check for a keyword selector that starts with the word 'add' or 5219/// 'set'. 5220static bool isSetterLikeSelector(Selector sel) { 5221 if (sel.isUnarySelector()) return false; 5222 5223 StringRef str = sel.getNameForSlot(0); 5224 while (!str.empty() && str.front() == '_') str = str.substr(1); 5225 if (str.startswith("set")) 5226 str = str.substr(3); 5227 else if (str.startswith("add")) { 5228 // Specially whitelist 'addOperationWithBlock:'. 5229 if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock")) 5230 return false; 5231 str = str.substr(3); 5232 } 5233 else 5234 return false; 5235 5236 if (str.empty()) return true; 5237 return !islower(str.front()); 5238} 5239 5240/// Check a message send to see if it's likely to cause a retain cycle. 5241void Sema::checkRetainCycles(ObjCMessageExpr *msg) { 5242 // Only check instance methods whose selector looks like a setter. 5243 if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector())) 5244 return; 5245 5246 // Try to find a variable that the receiver is strongly owned by. 5247 RetainCycleOwner owner; 5248 if (msg->getReceiverKind() == ObjCMessageExpr::Instance) { 5249 if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner)) 5250 return; 5251 } else { 5252 assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance); 5253 owner.Variable = getCurMethodDecl()->getSelfDecl(); 5254 owner.Loc = msg->getSuperLoc(); 5255 owner.Range = msg->getSuperLoc(); 5256 } 5257 5258 // Check whether the receiver is captured by any of the arguments. 5259 for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i) 5260 if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner)) 5261 return diagnoseRetainCycle(*this, capturer, owner); 5262} 5263 5264/// Check a property assign to see if it's likely to cause a retain cycle. 5265void Sema::checkRetainCycles(Expr *receiver, Expr *argument) { 5266 RetainCycleOwner owner; 5267 if (!findRetainCycleOwner(*this, receiver, owner)) 5268 return; 5269 5270 if (Expr *capturer = findCapturingExpr(*this, argument, owner)) 5271 diagnoseRetainCycle(*this, capturer, owner); 5272} 5273 5274bool Sema::checkUnsafeAssigns(SourceLocation Loc, 5275 QualType LHS, Expr *RHS) { 5276 Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime(); 5277 if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone) 5278 return false; 5279 // strip off any implicit cast added to get to the one arc-specific 5280 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 5281 if (cast->getCastKind() == CK_ARCConsumeObject) { 5282 Diag(Loc, diag::warn_arc_retained_assign) 5283 << (LT == Qualifiers::OCL_ExplicitNone) << 1 5284 << RHS->getSourceRange(); 5285 return true; 5286 } 5287 RHS = cast->getSubExpr(); 5288 } 5289 return false; 5290} 5291 5292void Sema::checkUnsafeExprAssigns(SourceLocation Loc, 5293 Expr *LHS, Expr *RHS) { 5294 QualType LHSType; 5295 // PropertyRef on LHS type need be directly obtained from 5296 // its declaration as it has a PsuedoType. 5297 ObjCPropertyRefExpr *PRE 5298 = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens()); 5299 if (PRE && !PRE->isImplicitProperty()) { 5300 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 5301 if (PD) 5302 LHSType = PD->getType(); 5303 } 5304 5305 if (LHSType.isNull()) 5306 LHSType = LHS->getType(); 5307 if (checkUnsafeAssigns(Loc, LHSType, RHS)) 5308 return; 5309 Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime(); 5310 // FIXME. Check for other life times. 5311 if (LT != Qualifiers::OCL_None) 5312 return; 5313 5314 if (PRE) { 5315 if (PRE->isImplicitProperty()) 5316 return; 5317 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 5318 if (!PD) 5319 return; 5320 5321 unsigned Attributes = PD->getPropertyAttributes(); 5322 if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) { 5323 // when 'assign' attribute was not explicitly specified 5324 // by user, ignore it and rely on property type itself 5325 // for lifetime info. 5326 unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten(); 5327 if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) && 5328 LHSType->isObjCRetainableType()) 5329 return; 5330 5331 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 5332 if (cast->getCastKind() == CK_ARCConsumeObject) { 5333 Diag(Loc, diag::warn_arc_retained_property_assign) 5334 << RHS->getSourceRange(); 5335 return; 5336 } 5337 RHS = cast->getSubExpr(); 5338 } 5339 } 5340 else if (Attributes & ObjCPropertyDecl::OBJC_PR_weak) { 5341 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 5342 if (cast->getCastKind() == CK_ARCConsumeObject) { 5343 Diag(Loc, diag::warn_arc_retained_assign) 5344 << 0 << 0<< RHS->getSourceRange(); 5345 return; 5346 } 5347 RHS = cast->getSubExpr(); 5348 } 5349 } 5350 } 5351} 5352 5353//===--- CHECK: Empty statement body (-Wempty-body) ---------------------===// 5354 5355namespace { 5356bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr, 5357 SourceLocation StmtLoc, 5358 const NullStmt *Body) { 5359 // Do not warn if the body is a macro that expands to nothing, e.g: 5360 // 5361 // #define CALL(x) 5362 // if (condition) 5363 // CALL(0); 5364 // 5365 if (Body->hasLeadingEmptyMacro()) 5366 return false; 5367 5368 // Get line numbers of statement and body. 5369 bool StmtLineInvalid; 5370 unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc, 5371 &StmtLineInvalid); 5372 if (StmtLineInvalid) 5373 return false; 5374 5375 bool BodyLineInvalid; 5376 unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(), 5377 &BodyLineInvalid); 5378 if (BodyLineInvalid) 5379 return false; 5380 5381 // Warn if null statement and body are on the same line. 5382 if (StmtLine != BodyLine) 5383 return false; 5384 5385 return true; 5386} 5387} // Unnamed namespace 5388 5389void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc, 5390 const Stmt *Body, 5391 unsigned DiagID) { 5392 // Since this is a syntactic check, don't emit diagnostic for template 5393 // instantiations, this just adds noise. 5394 if (CurrentInstantiationScope) 5395 return; 5396 5397 // The body should be a null statement. 5398 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 5399 if (!NBody) 5400 return; 5401 5402 // Do the usual checks. 5403 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 5404 return; 5405 5406 Diag(NBody->getSemiLoc(), DiagID); 5407 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 5408} 5409 5410void Sema::DiagnoseEmptyLoopBody(const Stmt *S, 5411 const Stmt *PossibleBody) { 5412 assert(!CurrentInstantiationScope); // Ensured by caller 5413 5414 SourceLocation StmtLoc; 5415 const Stmt *Body; 5416 unsigned DiagID; 5417 if (const ForStmt *FS = dyn_cast<ForStmt>(S)) { 5418 StmtLoc = FS->getRParenLoc(); 5419 Body = FS->getBody(); 5420 DiagID = diag::warn_empty_for_body; 5421 } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) { 5422 StmtLoc = WS->getCond()->getSourceRange().getEnd(); 5423 Body = WS->getBody(); 5424 DiagID = diag::warn_empty_while_body; 5425 } else 5426 return; // Neither `for' nor `while'. 5427 5428 // The body should be a null statement. 5429 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 5430 if (!NBody) 5431 return; 5432 5433 // Skip expensive checks if diagnostic is disabled. 5434 if (Diags.getDiagnosticLevel(DiagID, NBody->getSemiLoc()) == 5435 DiagnosticsEngine::Ignored) 5436 return; 5437 5438 // Do the usual checks. 5439 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 5440 return; 5441 5442 // `for(...);' and `while(...);' are popular idioms, so in order to keep 5443 // noise level low, emit diagnostics only if for/while is followed by a 5444 // CompoundStmt, e.g.: 5445 // for (int i = 0; i < n; i++); 5446 // { 5447 // a(i); 5448 // } 5449 // or if for/while is followed by a statement with more indentation 5450 // than for/while itself: 5451 // for (int i = 0; i < n; i++); 5452 // a(i); 5453 bool ProbableTypo = isa<CompoundStmt>(PossibleBody); 5454 if (!ProbableTypo) { 5455 bool BodyColInvalid; 5456 unsigned BodyCol = SourceMgr.getPresumedColumnNumber( 5457 PossibleBody->getLocStart(), 5458 &BodyColInvalid); 5459 if (BodyColInvalid) 5460 return; 5461 5462 bool StmtColInvalid; 5463 unsigned StmtCol = SourceMgr.getPresumedColumnNumber( 5464 S->getLocStart(), 5465 &StmtColInvalid); 5466 if (StmtColInvalid) 5467 return; 5468 5469 if (BodyCol > StmtCol) 5470 ProbableTypo = true; 5471 } 5472 5473 if (ProbableTypo) { 5474 Diag(NBody->getSemiLoc(), DiagID); 5475 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 5476 } 5477} 5478 5479//===--- Layout compatibility ----------------------------------------------// 5480 5481namespace { 5482 5483bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2); 5484 5485/// \brief Check if two enumeration types are layout-compatible. 5486bool isLayoutCompatible(ASTContext &C, EnumDecl *ED1, EnumDecl *ED2) { 5487 // C++11 [dcl.enum] p8: 5488 // Two enumeration types are layout-compatible if they have the same 5489 // underlying type. 5490 return ED1->isComplete() && ED2->isComplete() && 5491 C.hasSameType(ED1->getIntegerType(), ED2->getIntegerType()); 5492} 5493 5494/// \brief Check if two fields are layout-compatible. 5495bool isLayoutCompatible(ASTContext &C, FieldDecl *Field1, FieldDecl *Field2) { 5496 if (!isLayoutCompatible(C, Field1->getType(), Field2->getType())) 5497 return false; 5498 5499 if (Field1->isBitField() != Field2->isBitField()) 5500 return false; 5501 5502 if (Field1->isBitField()) { 5503 // Make sure that the bit-fields are the same length. 5504 unsigned Bits1 = Field1->getBitWidthValue(C); 5505 unsigned Bits2 = Field2->getBitWidthValue(C); 5506 5507 if (Bits1 != Bits2) 5508 return false; 5509 } 5510 5511 return true; 5512} 5513 5514/// \brief Check if two standard-layout structs are layout-compatible. 5515/// (C++11 [class.mem] p17) 5516bool isLayoutCompatibleStruct(ASTContext &C, 5517 RecordDecl *RD1, 5518 RecordDecl *RD2) { 5519 // If both records are C++ classes, check that base classes match. 5520 if (const CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(RD1)) { 5521 // If one of records is a CXXRecordDecl we are in C++ mode, 5522 // thus the other one is a CXXRecordDecl, too. 5523 const CXXRecordDecl *D2CXX = cast<CXXRecordDecl>(RD2); 5524 // Check number of base classes. 5525 if (D1CXX->getNumBases() != D2CXX->getNumBases()) 5526 return false; 5527 5528 // Check the base classes. 5529 for (CXXRecordDecl::base_class_const_iterator 5530 Base1 = D1CXX->bases_begin(), 5531 BaseEnd1 = D1CXX->bases_end(), 5532 Base2 = D2CXX->bases_begin(); 5533 Base1 != BaseEnd1; 5534 ++Base1, ++Base2) { 5535 if (!isLayoutCompatible(C, Base1->getType(), Base2->getType())) 5536 return false; 5537 } 5538 } else if (const CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(RD2)) { 5539 // If only RD2 is a C++ class, it should have zero base classes. 5540 if (D2CXX->getNumBases() > 0) 5541 return false; 5542 } 5543 5544 // Check the fields. 5545 RecordDecl::field_iterator Field2 = RD2->field_begin(), 5546 Field2End = RD2->field_end(), 5547 Field1 = RD1->field_begin(), 5548 Field1End = RD1->field_end(); 5549 for ( ; Field1 != Field1End && Field2 != Field2End; ++Field1, ++Field2) { 5550 if (!isLayoutCompatible(C, *Field1, *Field2)) 5551 return false; 5552 } 5553 if (Field1 != Field1End || Field2 != Field2End) 5554 return false; 5555 5556 return true; 5557} 5558 5559/// \brief Check if two standard-layout unions are layout-compatible. 5560/// (C++11 [class.mem] p18) 5561bool isLayoutCompatibleUnion(ASTContext &C, 5562 RecordDecl *RD1, 5563 RecordDecl *RD2) { 5564 llvm::SmallPtrSet<FieldDecl *, 8> UnmatchedFields; 5565 for (RecordDecl::field_iterator Field2 = RD2->field_begin(), 5566 Field2End = RD2->field_end(); 5567 Field2 != Field2End; ++Field2) { 5568 UnmatchedFields.insert(*Field2); 5569 } 5570 5571 for (RecordDecl::field_iterator Field1 = RD1->field_begin(), 5572 Field1End = RD1->field_end(); 5573 Field1 != Field1End; ++Field1) { 5574 llvm::SmallPtrSet<FieldDecl *, 8>::iterator 5575 I = UnmatchedFields.begin(), 5576 E = UnmatchedFields.end(); 5577 5578 for ( ; I != E; ++I) { 5579 if (isLayoutCompatible(C, *Field1, *I)) { 5580 bool Result = UnmatchedFields.erase(*I); 5581 (void) Result; 5582 assert(Result); 5583 break; 5584 } 5585 } 5586 if (I == E) 5587 return false; 5588 } 5589 5590 return UnmatchedFields.empty(); 5591} 5592 5593bool isLayoutCompatible(ASTContext &C, RecordDecl *RD1, RecordDecl *RD2) { 5594 if (RD1->isUnion() != RD2->isUnion()) 5595 return false; 5596 5597 if (RD1->isUnion()) 5598 return isLayoutCompatibleUnion(C, RD1, RD2); 5599 else 5600 return isLayoutCompatibleStruct(C, RD1, RD2); 5601} 5602 5603/// \brief Check if two types are layout-compatible in C++11 sense. 5604bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2) { 5605 if (T1.isNull() || T2.isNull()) 5606 return false; 5607 5608 // C++11 [basic.types] p11: 5609 // If two types T1 and T2 are the same type, then T1 and T2 are 5610 // layout-compatible types. 5611 if (C.hasSameType(T1, T2)) 5612 return true; 5613 5614 T1 = T1.getCanonicalType().getUnqualifiedType(); 5615 T2 = T2.getCanonicalType().getUnqualifiedType(); 5616 5617 const Type::TypeClass TC1 = T1->getTypeClass(); 5618 const Type::TypeClass TC2 = T2->getTypeClass(); 5619 5620 if (TC1 != TC2) 5621 return false; 5622 5623 if (TC1 == Type::Enum) { 5624 return isLayoutCompatible(C, 5625 cast<EnumType>(T1)->getDecl(), 5626 cast<EnumType>(T2)->getDecl()); 5627 } else if (TC1 == Type::Record) { 5628 if (!T1->isStandardLayoutType() || !T2->isStandardLayoutType()) 5629 return false; 5630 5631 return isLayoutCompatible(C, 5632 cast<RecordType>(T1)->getDecl(), 5633 cast<RecordType>(T2)->getDecl()); 5634 } 5635 5636 return false; 5637} 5638} 5639 5640//===--- CHECK: pointer_with_type_tag attribute: datatypes should match ----// 5641 5642namespace { 5643/// \brief Given a type tag expression find the type tag itself. 5644/// 5645/// \param TypeExpr Type tag expression, as it appears in user's code. 5646/// 5647/// \param VD Declaration of an identifier that appears in a type tag. 5648/// 5649/// \param MagicValue Type tag magic value. 5650bool FindTypeTagExpr(const Expr *TypeExpr, const ASTContext &Ctx, 5651 const ValueDecl **VD, uint64_t *MagicValue) { 5652 while(true) { 5653 if (!TypeExpr) 5654 return false; 5655 5656 TypeExpr = TypeExpr->IgnoreParenImpCasts()->IgnoreParenCasts(); 5657 5658 switch (TypeExpr->getStmtClass()) { 5659 case Stmt::UnaryOperatorClass: { 5660 const UnaryOperator *UO = cast<UnaryOperator>(TypeExpr); 5661 if (UO->getOpcode() == UO_AddrOf || UO->getOpcode() == UO_Deref) { 5662 TypeExpr = UO->getSubExpr(); 5663 continue; 5664 } 5665 return false; 5666 } 5667 5668 case Stmt::DeclRefExprClass: { 5669 const DeclRefExpr *DRE = cast<DeclRefExpr>(TypeExpr); 5670 *VD = DRE->getDecl(); 5671 return true; 5672 } 5673 5674 case Stmt::IntegerLiteralClass: { 5675 const IntegerLiteral *IL = cast<IntegerLiteral>(TypeExpr); 5676 llvm::APInt MagicValueAPInt = IL->getValue(); 5677 if (MagicValueAPInt.getActiveBits() <= 64) { 5678 *MagicValue = MagicValueAPInt.getZExtValue(); 5679 return true; 5680 } else 5681 return false; 5682 } 5683 5684 case Stmt::BinaryConditionalOperatorClass: 5685 case Stmt::ConditionalOperatorClass: { 5686 const AbstractConditionalOperator *ACO = 5687 cast<AbstractConditionalOperator>(TypeExpr); 5688 bool Result; 5689 if (ACO->getCond()->EvaluateAsBooleanCondition(Result, Ctx)) { 5690 if (Result) 5691 TypeExpr = ACO->getTrueExpr(); 5692 else 5693 TypeExpr = ACO->getFalseExpr(); 5694 continue; 5695 } 5696 return false; 5697 } 5698 5699 case Stmt::BinaryOperatorClass: { 5700 const BinaryOperator *BO = cast<BinaryOperator>(TypeExpr); 5701 if (BO->getOpcode() == BO_Comma) { 5702 TypeExpr = BO->getRHS(); 5703 continue; 5704 } 5705 return false; 5706 } 5707 5708 default: 5709 return false; 5710 } 5711 } 5712} 5713 5714/// \brief Retrieve the C type corresponding to type tag TypeExpr. 5715/// 5716/// \param TypeExpr Expression that specifies a type tag. 5717/// 5718/// \param MagicValues Registered magic values. 5719/// 5720/// \param FoundWrongKind Set to true if a type tag was found, but of a wrong 5721/// kind. 5722/// 5723/// \param TypeInfo Information about the corresponding C type. 5724/// 5725/// \returns true if the corresponding C type was found. 5726bool GetMatchingCType( 5727 const IdentifierInfo *ArgumentKind, 5728 const Expr *TypeExpr, const ASTContext &Ctx, 5729 const llvm::DenseMap<Sema::TypeTagMagicValue, 5730 Sema::TypeTagData> *MagicValues, 5731 bool &FoundWrongKind, 5732 Sema::TypeTagData &TypeInfo) { 5733 FoundWrongKind = false; 5734 5735 // Variable declaration that has type_tag_for_datatype attribute. 5736 const ValueDecl *VD = NULL; 5737 5738 uint64_t MagicValue; 5739 5740 if (!FindTypeTagExpr(TypeExpr, Ctx, &VD, &MagicValue)) 5741 return false; 5742 5743 if (VD) { 5744 for (specific_attr_iterator<TypeTagForDatatypeAttr> 5745 I = VD->specific_attr_begin<TypeTagForDatatypeAttr>(), 5746 E = VD->specific_attr_end<TypeTagForDatatypeAttr>(); 5747 I != E; ++I) { 5748 if (I->getArgumentKind() != ArgumentKind) { 5749 FoundWrongKind = true; 5750 return false; 5751 } 5752 TypeInfo.Type = I->getMatchingCType(); 5753 TypeInfo.LayoutCompatible = I->getLayoutCompatible(); 5754 TypeInfo.MustBeNull = I->getMustBeNull(); 5755 return true; 5756 } 5757 return false; 5758 } 5759 5760 if (!MagicValues) 5761 return false; 5762 5763 llvm::DenseMap<Sema::TypeTagMagicValue, 5764 Sema::TypeTagData>::const_iterator I = 5765 MagicValues->find(std::make_pair(ArgumentKind, MagicValue)); 5766 if (I == MagicValues->end()) 5767 return false; 5768 5769 TypeInfo = I->second; 5770 return true; 5771} 5772} // unnamed namespace 5773 5774void Sema::RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind, 5775 uint64_t MagicValue, QualType Type, 5776 bool LayoutCompatible, 5777 bool MustBeNull) { 5778 if (!TypeTagForDatatypeMagicValues) 5779 TypeTagForDatatypeMagicValues.reset( 5780 new llvm::DenseMap<TypeTagMagicValue, TypeTagData>); 5781 5782 TypeTagMagicValue Magic(ArgumentKind, MagicValue); 5783 (*TypeTagForDatatypeMagicValues)[Magic] = 5784 TypeTagData(Type, LayoutCompatible, MustBeNull); 5785} 5786 5787namespace { 5788bool IsSameCharType(QualType T1, QualType T2) { 5789 const BuiltinType *BT1 = T1->getAs<BuiltinType>(); 5790 if (!BT1) 5791 return false; 5792 5793 const BuiltinType *BT2 = T2->getAs<BuiltinType>(); 5794 if (!BT2) 5795 return false; 5796 5797 BuiltinType::Kind T1Kind = BT1->getKind(); 5798 BuiltinType::Kind T2Kind = BT2->getKind(); 5799 5800 return (T1Kind == BuiltinType::SChar && T2Kind == BuiltinType::Char_S) || 5801 (T1Kind == BuiltinType::UChar && T2Kind == BuiltinType::Char_U) || 5802 (T1Kind == BuiltinType::Char_U && T2Kind == BuiltinType::UChar) || 5803 (T1Kind == BuiltinType::Char_S && T2Kind == BuiltinType::SChar); 5804} 5805} // unnamed namespace 5806 5807void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr, 5808 const Expr * const *ExprArgs) { 5809 const IdentifierInfo *ArgumentKind = Attr->getArgumentKind(); 5810 bool IsPointerAttr = Attr->getIsPointer(); 5811 5812 const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()]; 5813 bool FoundWrongKind; 5814 TypeTagData TypeInfo; 5815 if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context, 5816 TypeTagForDatatypeMagicValues.get(), 5817 FoundWrongKind, TypeInfo)) { 5818 if (FoundWrongKind) 5819 Diag(TypeTagExpr->getExprLoc(), 5820 diag::warn_type_tag_for_datatype_wrong_kind) 5821 << TypeTagExpr->getSourceRange(); 5822 return; 5823 } 5824 5825 const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()]; 5826 if (IsPointerAttr) { 5827 // Skip implicit cast of pointer to `void *' (as a function argument). 5828 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr)) 5829 if (ICE->getType()->isVoidPointerType()) 5830 ArgumentExpr = ICE->getSubExpr(); 5831 } 5832 QualType ArgumentType = ArgumentExpr->getType(); 5833 5834 // Passing a `void*' pointer shouldn't trigger a warning. 5835 if (IsPointerAttr && ArgumentType->isVoidPointerType()) 5836 return; 5837 5838 if (TypeInfo.MustBeNull) { 5839 // Type tag with matching void type requires a null pointer. 5840 if (!ArgumentExpr->isNullPointerConstant(Context, 5841 Expr::NPC_ValueDependentIsNotNull)) { 5842 Diag(ArgumentExpr->getExprLoc(), 5843 diag::warn_type_safety_null_pointer_required) 5844 << ArgumentKind->getName() 5845 << ArgumentExpr->getSourceRange() 5846 << TypeTagExpr->getSourceRange(); 5847 } 5848 return; 5849 } 5850 5851 QualType RequiredType = TypeInfo.Type; 5852 if (IsPointerAttr) 5853 RequiredType = Context.getPointerType(RequiredType); 5854 5855 bool mismatch = false; 5856 if (!TypeInfo.LayoutCompatible) { 5857 mismatch = !Context.hasSameType(ArgumentType, RequiredType); 5858 5859 // C++11 [basic.fundamental] p1: 5860 // Plain char, signed char, and unsigned char are three distinct types. 5861 // 5862 // But we treat plain `char' as equivalent to `signed char' or `unsigned 5863 // char' depending on the current char signedness mode. 5864 if (mismatch) 5865 if ((IsPointerAttr && IsSameCharType(ArgumentType->getPointeeType(), 5866 RequiredType->getPointeeType())) || 5867 (!IsPointerAttr && IsSameCharType(ArgumentType, RequiredType))) 5868 mismatch = false; 5869 } else 5870 if (IsPointerAttr) 5871 mismatch = !isLayoutCompatible(Context, 5872 ArgumentType->getPointeeType(), 5873 RequiredType->getPointeeType()); 5874 else 5875 mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType); 5876 5877 if (mismatch) 5878 Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch) 5879 << ArgumentType << ArgumentKind->getName() 5880 << TypeInfo.LayoutCompatible << RequiredType 5881 << ArgumentExpr->getSourceRange() 5882 << TypeTagExpr->getSourceRange(); 5883} 5884 5885