SemaChecking.cpp revision 0538f0e9200df56974b5a71bc276dbce456e9781
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/SemaInternal.h" 16#include "clang/AST/ASTContext.h" 17#include "clang/AST/CharUnits.h" 18#include "clang/AST/DeclCXX.h" 19#include "clang/AST/DeclObjC.h" 20#include "clang/AST/EvaluatedExprVisitor.h" 21#include "clang/AST/Expr.h" 22#include "clang/AST/ExprCXX.h" 23#include "clang/AST/ExprObjC.h" 24#include "clang/AST/StmtCXX.h" 25#include "clang/AST/StmtObjC.h" 26#include "clang/Analysis/Analyses/FormatString.h" 27#include "clang/Basic/CharInfo.h" 28#include "clang/Basic/TargetBuiltins.h" 29#include "clang/Basic/TargetInfo.h" 30#include "clang/Lex/Preprocessor.h" 31#include "clang/Sema/Initialization.h" 32#include "clang/Sema/Lookup.h" 33#include "clang/Sema/ScopeInfo.h" 34#include "clang/Sema/Sema.h" 35#include "llvm/ADT/BitVector.h" 36#include "llvm/ADT/STLExtras.h" 37#include "llvm/ADT/SmallString.h" 38#include "llvm/Support/ConvertUTF.h" 39#include "llvm/Support/raw_ostream.h" 40#include <limits> 41using namespace clang; 42using namespace sema; 43 44SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL, 45 unsigned ByteNo) const { 46 return SL->getLocationOfByte(ByteNo, PP.getSourceManager(), 47 PP.getLangOpts(), PP.getTargetInfo()); 48} 49 50/// Checks that a call expression's argument count is the desired number. 51/// This is useful when doing custom type-checking. Returns true on error. 52static bool checkArgCount(Sema &S, CallExpr *call, unsigned desiredArgCount) { 53 unsigned argCount = call->getNumArgs(); 54 if (argCount == desiredArgCount) return false; 55 56 if (argCount < desiredArgCount) 57 return S.Diag(call->getLocEnd(), diag::err_typecheck_call_too_few_args) 58 << 0 /*function call*/ << desiredArgCount << argCount 59 << call->getSourceRange(); 60 61 // Highlight all the excess arguments. 62 SourceRange range(call->getArg(desiredArgCount)->getLocStart(), 63 call->getArg(argCount - 1)->getLocEnd()); 64 65 return S.Diag(range.getBegin(), diag::err_typecheck_call_too_many_args) 66 << 0 /*function call*/ << desiredArgCount << argCount 67 << call->getArg(1)->getSourceRange(); 68} 69 70/// Check that the first argument to __builtin_annotation is an integer 71/// and the second argument is a non-wide string literal. 72static bool SemaBuiltinAnnotation(Sema &S, CallExpr *TheCall) { 73 if (checkArgCount(S, TheCall, 2)) 74 return true; 75 76 // First argument should be an integer. 77 Expr *ValArg = TheCall->getArg(0); 78 QualType Ty = ValArg->getType(); 79 if (!Ty->isIntegerType()) { 80 S.Diag(ValArg->getLocStart(), diag::err_builtin_annotation_first_arg) 81 << ValArg->getSourceRange(); 82 return true; 83 } 84 85 // Second argument should be a constant string. 86 Expr *StrArg = TheCall->getArg(1)->IgnoreParenCasts(); 87 StringLiteral *Literal = dyn_cast<StringLiteral>(StrArg); 88 if (!Literal || !Literal->isAscii()) { 89 S.Diag(StrArg->getLocStart(), diag::err_builtin_annotation_second_arg) 90 << StrArg->getSourceRange(); 91 return true; 92 } 93 94 TheCall->setType(Ty); 95 return false; 96} 97 98ExprResult 99Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 100 ExprResult TheCallResult(Owned(TheCall)); 101 102 // Find out if any arguments are required to be integer constant expressions. 103 unsigned ICEArguments = 0; 104 ASTContext::GetBuiltinTypeError Error; 105 Context.GetBuiltinType(BuiltinID, Error, &ICEArguments); 106 if (Error != ASTContext::GE_None) 107 ICEArguments = 0; // Don't diagnose previously diagnosed errors. 108 109 // If any arguments are required to be ICE's, check and diagnose. 110 for (unsigned ArgNo = 0; ICEArguments != 0; ++ArgNo) { 111 // Skip arguments not required to be ICE's. 112 if ((ICEArguments & (1 << ArgNo)) == 0) continue; 113 114 llvm::APSInt Result; 115 if (SemaBuiltinConstantArg(TheCall, ArgNo, Result)) 116 return true; 117 ICEArguments &= ~(1 << ArgNo); 118 } 119 120 switch (BuiltinID) { 121 case Builtin::BI__builtin___CFStringMakeConstantString: 122 assert(TheCall->getNumArgs() == 1 && 123 "Wrong # arguments to builtin CFStringMakeConstantString"); 124 if (CheckObjCString(TheCall->getArg(0))) 125 return ExprError(); 126 break; 127 case Builtin::BI__builtin_stdarg_start: 128 case Builtin::BI__builtin_va_start: 129 if (SemaBuiltinVAStart(TheCall)) 130 return ExprError(); 131 break; 132 case Builtin::BI__builtin_isgreater: 133 case Builtin::BI__builtin_isgreaterequal: 134 case Builtin::BI__builtin_isless: 135 case Builtin::BI__builtin_islessequal: 136 case Builtin::BI__builtin_islessgreater: 137 case Builtin::BI__builtin_isunordered: 138 if (SemaBuiltinUnorderedCompare(TheCall)) 139 return ExprError(); 140 break; 141 case Builtin::BI__builtin_fpclassify: 142 if (SemaBuiltinFPClassification(TheCall, 6)) 143 return ExprError(); 144 break; 145 case Builtin::BI__builtin_isfinite: 146 case Builtin::BI__builtin_isinf: 147 case Builtin::BI__builtin_isinf_sign: 148 case Builtin::BI__builtin_isnan: 149 case Builtin::BI__builtin_isnormal: 150 if (SemaBuiltinFPClassification(TheCall, 1)) 151 return ExprError(); 152 break; 153 case Builtin::BI__builtin_shufflevector: 154 return SemaBuiltinShuffleVector(TheCall); 155 // TheCall will be freed by the smart pointer here, but that's fine, since 156 // SemaBuiltinShuffleVector guts it, but then doesn't release it. 157 case Builtin::BI__builtin_prefetch: 158 if (SemaBuiltinPrefetch(TheCall)) 159 return ExprError(); 160 break; 161 case Builtin::BI__builtin_object_size: 162 if (SemaBuiltinObjectSize(TheCall)) 163 return ExprError(); 164 break; 165 case Builtin::BI__builtin_longjmp: 166 if (SemaBuiltinLongjmp(TheCall)) 167 return ExprError(); 168 break; 169 170 case Builtin::BI__builtin_classify_type: 171 if (checkArgCount(*this, TheCall, 1)) return true; 172 TheCall->setType(Context.IntTy); 173 break; 174 case Builtin::BI__builtin_constant_p: 175 if (checkArgCount(*this, TheCall, 1)) return true; 176 TheCall->setType(Context.IntTy); 177 break; 178 case Builtin::BI__sync_fetch_and_add: 179 case Builtin::BI__sync_fetch_and_add_1: 180 case Builtin::BI__sync_fetch_and_add_2: 181 case Builtin::BI__sync_fetch_and_add_4: 182 case Builtin::BI__sync_fetch_and_add_8: 183 case Builtin::BI__sync_fetch_and_add_16: 184 case Builtin::BI__sync_fetch_and_sub: 185 case Builtin::BI__sync_fetch_and_sub_1: 186 case Builtin::BI__sync_fetch_and_sub_2: 187 case Builtin::BI__sync_fetch_and_sub_4: 188 case Builtin::BI__sync_fetch_and_sub_8: 189 case Builtin::BI__sync_fetch_and_sub_16: 190 case Builtin::BI__sync_fetch_and_or: 191 case Builtin::BI__sync_fetch_and_or_1: 192 case Builtin::BI__sync_fetch_and_or_2: 193 case Builtin::BI__sync_fetch_and_or_4: 194 case Builtin::BI__sync_fetch_and_or_8: 195 case Builtin::BI__sync_fetch_and_or_16: 196 case Builtin::BI__sync_fetch_and_and: 197 case Builtin::BI__sync_fetch_and_and_1: 198 case Builtin::BI__sync_fetch_and_and_2: 199 case Builtin::BI__sync_fetch_and_and_4: 200 case Builtin::BI__sync_fetch_and_and_8: 201 case Builtin::BI__sync_fetch_and_and_16: 202 case Builtin::BI__sync_fetch_and_xor: 203 case Builtin::BI__sync_fetch_and_xor_1: 204 case Builtin::BI__sync_fetch_and_xor_2: 205 case Builtin::BI__sync_fetch_and_xor_4: 206 case Builtin::BI__sync_fetch_and_xor_8: 207 case Builtin::BI__sync_fetch_and_xor_16: 208 case Builtin::BI__sync_add_and_fetch: 209 case Builtin::BI__sync_add_and_fetch_1: 210 case Builtin::BI__sync_add_and_fetch_2: 211 case Builtin::BI__sync_add_and_fetch_4: 212 case Builtin::BI__sync_add_and_fetch_8: 213 case Builtin::BI__sync_add_and_fetch_16: 214 case Builtin::BI__sync_sub_and_fetch: 215 case Builtin::BI__sync_sub_and_fetch_1: 216 case Builtin::BI__sync_sub_and_fetch_2: 217 case Builtin::BI__sync_sub_and_fetch_4: 218 case Builtin::BI__sync_sub_and_fetch_8: 219 case Builtin::BI__sync_sub_and_fetch_16: 220 case Builtin::BI__sync_and_and_fetch: 221 case Builtin::BI__sync_and_and_fetch_1: 222 case Builtin::BI__sync_and_and_fetch_2: 223 case Builtin::BI__sync_and_and_fetch_4: 224 case Builtin::BI__sync_and_and_fetch_8: 225 case Builtin::BI__sync_and_and_fetch_16: 226 case Builtin::BI__sync_or_and_fetch: 227 case Builtin::BI__sync_or_and_fetch_1: 228 case Builtin::BI__sync_or_and_fetch_2: 229 case Builtin::BI__sync_or_and_fetch_4: 230 case Builtin::BI__sync_or_and_fetch_8: 231 case Builtin::BI__sync_or_and_fetch_16: 232 case Builtin::BI__sync_xor_and_fetch: 233 case Builtin::BI__sync_xor_and_fetch_1: 234 case Builtin::BI__sync_xor_and_fetch_2: 235 case Builtin::BI__sync_xor_and_fetch_4: 236 case Builtin::BI__sync_xor_and_fetch_8: 237 case Builtin::BI__sync_xor_and_fetch_16: 238 case Builtin::BI__sync_val_compare_and_swap: 239 case Builtin::BI__sync_val_compare_and_swap_1: 240 case Builtin::BI__sync_val_compare_and_swap_2: 241 case Builtin::BI__sync_val_compare_and_swap_4: 242 case Builtin::BI__sync_val_compare_and_swap_8: 243 case Builtin::BI__sync_val_compare_and_swap_16: 244 case Builtin::BI__sync_bool_compare_and_swap: 245 case Builtin::BI__sync_bool_compare_and_swap_1: 246 case Builtin::BI__sync_bool_compare_and_swap_2: 247 case Builtin::BI__sync_bool_compare_and_swap_4: 248 case Builtin::BI__sync_bool_compare_and_swap_8: 249 case Builtin::BI__sync_bool_compare_and_swap_16: 250 case Builtin::BI__sync_lock_test_and_set: 251 case Builtin::BI__sync_lock_test_and_set_1: 252 case Builtin::BI__sync_lock_test_and_set_2: 253 case Builtin::BI__sync_lock_test_and_set_4: 254 case Builtin::BI__sync_lock_test_and_set_8: 255 case Builtin::BI__sync_lock_test_and_set_16: 256 case Builtin::BI__sync_lock_release: 257 case Builtin::BI__sync_lock_release_1: 258 case Builtin::BI__sync_lock_release_2: 259 case Builtin::BI__sync_lock_release_4: 260 case Builtin::BI__sync_lock_release_8: 261 case Builtin::BI__sync_lock_release_16: 262 case Builtin::BI__sync_swap: 263 case Builtin::BI__sync_swap_1: 264 case Builtin::BI__sync_swap_2: 265 case Builtin::BI__sync_swap_4: 266 case Builtin::BI__sync_swap_8: 267 case Builtin::BI__sync_swap_16: 268 return SemaBuiltinAtomicOverloaded(TheCallResult); 269#define BUILTIN(ID, TYPE, ATTRS) 270#define ATOMIC_BUILTIN(ID, TYPE, ATTRS) \ 271 case Builtin::BI##ID: \ 272 return SemaAtomicOpsOverloaded(TheCallResult, AtomicExpr::AO##ID); 273#include "clang/Basic/Builtins.def" 274 case Builtin::BI__builtin_annotation: 275 if (SemaBuiltinAnnotation(*this, TheCall)) 276 return ExprError(); 277 break; 278 } 279 280 // Since the target specific builtins for each arch overlap, only check those 281 // of the arch we are compiling for. 282 if (BuiltinID >= Builtin::FirstTSBuiltin) { 283 switch (Context.getTargetInfo().getTriple().getArch()) { 284 case llvm::Triple::arm: 285 case llvm::Triple::thumb: 286 if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall)) 287 return ExprError(); 288 break; 289 case llvm::Triple::mips: 290 case llvm::Triple::mipsel: 291 case llvm::Triple::mips64: 292 case llvm::Triple::mips64el: 293 if (CheckMipsBuiltinFunctionCall(BuiltinID, TheCall)) 294 return ExprError(); 295 break; 296 default: 297 break; 298 } 299 } 300 301 return TheCallResult; 302} 303 304// Get the valid immediate range for the specified NEON type code. 305static unsigned RFT(unsigned t, bool shift = false) { 306 NeonTypeFlags Type(t); 307 int IsQuad = Type.isQuad(); 308 switch (Type.getEltType()) { 309 case NeonTypeFlags::Int8: 310 case NeonTypeFlags::Poly8: 311 return shift ? 7 : (8 << IsQuad) - 1; 312 case NeonTypeFlags::Int16: 313 case NeonTypeFlags::Poly16: 314 return shift ? 15 : (4 << IsQuad) - 1; 315 case NeonTypeFlags::Int32: 316 return shift ? 31 : (2 << IsQuad) - 1; 317 case NeonTypeFlags::Int64: 318 return shift ? 63 : (1 << IsQuad) - 1; 319 case NeonTypeFlags::Float16: 320 assert(!shift && "cannot shift float types!"); 321 return (4 << IsQuad) - 1; 322 case NeonTypeFlags::Float32: 323 assert(!shift && "cannot shift float types!"); 324 return (2 << IsQuad) - 1; 325 } 326 llvm_unreachable("Invalid NeonTypeFlag!"); 327} 328 329/// getNeonEltType - Return the QualType corresponding to the elements of 330/// the vector type specified by the NeonTypeFlags. This is used to check 331/// the pointer arguments for Neon load/store intrinsics. 332static QualType getNeonEltType(NeonTypeFlags Flags, ASTContext &Context) { 333 switch (Flags.getEltType()) { 334 case NeonTypeFlags::Int8: 335 return Flags.isUnsigned() ? Context.UnsignedCharTy : Context.SignedCharTy; 336 case NeonTypeFlags::Int16: 337 return Flags.isUnsigned() ? Context.UnsignedShortTy : Context.ShortTy; 338 case NeonTypeFlags::Int32: 339 return Flags.isUnsigned() ? Context.UnsignedIntTy : Context.IntTy; 340 case NeonTypeFlags::Int64: 341 return Flags.isUnsigned() ? Context.UnsignedLongLongTy : Context.LongLongTy; 342 case NeonTypeFlags::Poly8: 343 return Context.SignedCharTy; 344 case NeonTypeFlags::Poly16: 345 return Context.ShortTy; 346 case NeonTypeFlags::Float16: 347 return Context.UnsignedShortTy; 348 case NeonTypeFlags::Float32: 349 return Context.FloatTy; 350 } 351 llvm_unreachable("Invalid NeonTypeFlag!"); 352} 353 354bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 355 llvm::APSInt Result; 356 357 uint64_t mask = 0; 358 unsigned TV = 0; 359 int PtrArgNum = -1; 360 bool HasConstPtr = false; 361 switch (BuiltinID) { 362#define GET_NEON_OVERLOAD_CHECK 363#include "clang/Basic/arm_neon.inc" 364#undef GET_NEON_OVERLOAD_CHECK 365 } 366 367 // For NEON intrinsics which are overloaded on vector element type, validate 368 // the immediate which specifies which variant to emit. 369 unsigned ImmArg = TheCall->getNumArgs()-1; 370 if (mask) { 371 if (SemaBuiltinConstantArg(TheCall, ImmArg, Result)) 372 return true; 373 374 TV = Result.getLimitedValue(64); 375 if ((TV > 63) || (mask & (1ULL << TV)) == 0) 376 return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code) 377 << TheCall->getArg(ImmArg)->getSourceRange(); 378 } 379 380 if (PtrArgNum >= 0) { 381 // Check that pointer arguments have the specified type. 382 Expr *Arg = TheCall->getArg(PtrArgNum); 383 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) 384 Arg = ICE->getSubExpr(); 385 ExprResult RHS = DefaultFunctionArrayLvalueConversion(Arg); 386 QualType RHSTy = RHS.get()->getType(); 387 QualType EltTy = getNeonEltType(NeonTypeFlags(TV), Context); 388 if (HasConstPtr) 389 EltTy = EltTy.withConst(); 390 QualType LHSTy = Context.getPointerType(EltTy); 391 AssignConvertType ConvTy; 392 ConvTy = CheckSingleAssignmentConstraints(LHSTy, RHS); 393 if (RHS.isInvalid()) 394 return true; 395 if (DiagnoseAssignmentResult(ConvTy, Arg->getLocStart(), LHSTy, RHSTy, 396 RHS.get(), AA_Assigning)) 397 return true; 398 } 399 400 // For NEON intrinsics which take an immediate value as part of the 401 // instruction, range check them here. 402 unsigned i = 0, l = 0, u = 0; 403 switch (BuiltinID) { 404 default: return false; 405 case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break; 406 case ARM::BI__builtin_arm_usat: i = 1; u = 31; break; 407 case ARM::BI__builtin_arm_vcvtr_f: 408 case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break; 409#define GET_NEON_IMMEDIATE_CHECK 410#include "clang/Basic/arm_neon.inc" 411#undef GET_NEON_IMMEDIATE_CHECK 412 }; 413 414 // We can't check the value of a dependent argument. 415 if (TheCall->getArg(i)->isTypeDependent() || 416 TheCall->getArg(i)->isValueDependent()) 417 return false; 418 419 // Check that the immediate argument is actually a constant. 420 if (SemaBuiltinConstantArg(TheCall, i, Result)) 421 return true; 422 423 // Range check against the upper/lower values for this isntruction. 424 unsigned Val = Result.getZExtValue(); 425 if (Val < l || Val > (u + l)) 426 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 427 << l << u+l << TheCall->getArg(i)->getSourceRange(); 428 429 // FIXME: VFP Intrinsics should error if VFP not present. 430 return false; 431} 432 433bool Sema::CheckMipsBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 434 unsigned i = 0, l = 0, u = 0; 435 switch (BuiltinID) { 436 default: return false; 437 case Mips::BI__builtin_mips_wrdsp: i = 1; l = 0; u = 63; break; 438 case Mips::BI__builtin_mips_rddsp: i = 0; l = 0; u = 63; break; 439 case Mips::BI__builtin_mips_append: i = 2; l = 0; u = 31; break; 440 case Mips::BI__builtin_mips_balign: i = 2; l = 0; u = 3; break; 441 case Mips::BI__builtin_mips_precr_sra_ph_w: i = 2; l = 0; u = 31; break; 442 case Mips::BI__builtin_mips_precr_sra_r_ph_w: i = 2; l = 0; u = 31; break; 443 case Mips::BI__builtin_mips_prepend: i = 2; l = 0; u = 31; break; 444 }; 445 446 // We can't check the value of a dependent argument. 447 if (TheCall->getArg(i)->isTypeDependent() || 448 TheCall->getArg(i)->isValueDependent()) 449 return false; 450 451 // Check that the immediate argument is actually a constant. 452 llvm::APSInt Result; 453 if (SemaBuiltinConstantArg(TheCall, i, Result)) 454 return true; 455 456 // Range check against the upper/lower values for this instruction. 457 unsigned Val = Result.getZExtValue(); 458 if (Val < l || Val > u) 459 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 460 << l << u << TheCall->getArg(i)->getSourceRange(); 461 462 return false; 463} 464 465/// Given a FunctionDecl's FormatAttr, attempts to populate the FomatStringInfo 466/// parameter with the FormatAttr's correct format_idx and firstDataArg. 467/// Returns true when the format fits the function and the FormatStringInfo has 468/// been populated. 469bool Sema::getFormatStringInfo(const FormatAttr *Format, bool IsCXXMember, 470 FormatStringInfo *FSI) { 471 FSI->HasVAListArg = Format->getFirstArg() == 0; 472 FSI->FormatIdx = Format->getFormatIdx() - 1; 473 FSI->FirstDataArg = FSI->HasVAListArg ? 0 : Format->getFirstArg() - 1; 474 475 // The way the format attribute works in GCC, the implicit this argument 476 // of member functions is counted. However, it doesn't appear in our own 477 // lists, so decrement format_idx in that case. 478 if (IsCXXMember) { 479 if(FSI->FormatIdx == 0) 480 return false; 481 --FSI->FormatIdx; 482 if (FSI->FirstDataArg != 0) 483 --FSI->FirstDataArg; 484 } 485 return true; 486} 487 488/// Handles the checks for format strings, non-POD arguments to vararg 489/// functions, and NULL arguments passed to non-NULL parameters. 490void Sema::checkCall(NamedDecl *FDecl, 491 ArrayRef<const Expr *> Args, 492 unsigned NumProtoArgs, 493 bool IsMemberFunction, 494 SourceLocation Loc, 495 SourceRange Range, 496 VariadicCallType CallType) { 497 if (CurContext->isDependentContext()) 498 return; 499 500 // Printf and scanf checking. 501 bool HandledFormatString = false; 502 if (FDecl) 503 for (specific_attr_iterator<FormatAttr> 504 I = FDecl->specific_attr_begin<FormatAttr>(), 505 E = FDecl->specific_attr_end<FormatAttr>(); I != E ; ++I) 506 if (CheckFormatArguments(*I, Args, IsMemberFunction, CallType, Loc, 507 Range)) 508 HandledFormatString = true; 509 510 // Refuse POD arguments that weren't caught by the format string 511 // checks above. 512 if (!HandledFormatString && CallType != VariadicDoesNotApply) 513 for (unsigned ArgIdx = NumProtoArgs; ArgIdx < Args.size(); ++ArgIdx) { 514 // Args[ArgIdx] can be null in malformed code. 515 if (const Expr *Arg = Args[ArgIdx]) 516 variadicArgumentPODCheck(Arg, CallType); 517 } 518 519 if (FDecl) { 520 for (specific_attr_iterator<NonNullAttr> 521 I = FDecl->specific_attr_begin<NonNullAttr>(), 522 E = FDecl->specific_attr_end<NonNullAttr>(); I != E; ++I) 523 CheckNonNullArguments(*I, Args.data(), Loc); 524 525 // Type safety checking. 526 for (specific_attr_iterator<ArgumentWithTypeTagAttr> 527 i = FDecl->specific_attr_begin<ArgumentWithTypeTagAttr>(), 528 e = FDecl->specific_attr_end<ArgumentWithTypeTagAttr>(); 529 i != e; ++i) { 530 CheckArgumentWithTypeTag(*i, Args.data()); 531 } 532 } 533} 534 535/// CheckConstructorCall - Check a constructor call for correctness and safety 536/// properties not enforced by the C type system. 537void Sema::CheckConstructorCall(FunctionDecl *FDecl, 538 ArrayRef<const Expr *> Args, 539 const FunctionProtoType *Proto, 540 SourceLocation Loc) { 541 VariadicCallType CallType = 542 Proto->isVariadic() ? VariadicConstructor : VariadicDoesNotApply; 543 checkCall(FDecl, Args, Proto->getNumArgs(), 544 /*IsMemberFunction=*/true, Loc, SourceRange(), CallType); 545} 546 547/// CheckFunctionCall - Check a direct function call for various correctness 548/// and safety properties not strictly enforced by the C type system. 549bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall, 550 const FunctionProtoType *Proto) { 551 bool IsMemberOperatorCall = isa<CXXOperatorCallExpr>(TheCall) && 552 isa<CXXMethodDecl>(FDecl); 553 bool IsMemberFunction = isa<CXXMemberCallExpr>(TheCall) || 554 IsMemberOperatorCall; 555 VariadicCallType CallType = getVariadicCallType(FDecl, Proto, 556 TheCall->getCallee()); 557 unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0; 558 Expr** Args = TheCall->getArgs(); 559 unsigned NumArgs = TheCall->getNumArgs(); 560 if (IsMemberOperatorCall) { 561 // If this is a call to a member operator, hide the first argument 562 // from checkCall. 563 // FIXME: Our choice of AST representation here is less than ideal. 564 ++Args; 565 --NumArgs; 566 } 567 checkCall(FDecl, llvm::makeArrayRef<const Expr *>(Args, NumArgs), 568 NumProtoArgs, 569 IsMemberFunction, TheCall->getRParenLoc(), 570 TheCall->getCallee()->getSourceRange(), CallType); 571 572 IdentifierInfo *FnInfo = FDecl->getIdentifier(); 573 // None of the checks below are needed for functions that don't have 574 // simple names (e.g., C++ conversion functions). 575 if (!FnInfo) 576 return false; 577 578 unsigned CMId = FDecl->getMemoryFunctionKind(); 579 if (CMId == 0) 580 return false; 581 582 // Handle memory setting and copying functions. 583 if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat) 584 CheckStrlcpycatArguments(TheCall, FnInfo); 585 else if (CMId == Builtin::BIstrncat) 586 CheckStrncatArguments(TheCall, FnInfo); 587 else 588 CheckMemaccessArguments(TheCall, CMId, FnInfo); 589 590 return false; 591} 592 593bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac, 594 ArrayRef<const Expr *> Args) { 595 VariadicCallType CallType = 596 Method->isVariadic() ? VariadicMethod : VariadicDoesNotApply; 597 598 checkCall(Method, Args, Method->param_size(), 599 /*IsMemberFunction=*/false, 600 lbrac, Method->getSourceRange(), CallType); 601 602 return false; 603} 604 605bool Sema::CheckPointerCall(NamedDecl *NDecl, CallExpr *TheCall, 606 const FunctionProtoType *Proto) { 607 const VarDecl *V = dyn_cast<VarDecl>(NDecl); 608 if (!V) 609 return false; 610 611 QualType Ty = V->getType(); 612 if (!Ty->isBlockPointerType() && !Ty->isFunctionPointerType()) 613 return false; 614 615 VariadicCallType CallType; 616 if (!Proto || !Proto->isVariadic()) { 617 CallType = VariadicDoesNotApply; 618 } else if (Ty->isBlockPointerType()) { 619 CallType = VariadicBlock; 620 } else { // Ty->isFunctionPointerType() 621 CallType = VariadicFunction; 622 } 623 unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0; 624 625 checkCall(NDecl, 626 llvm::makeArrayRef<const Expr *>(TheCall->getArgs(), 627 TheCall->getNumArgs()), 628 NumProtoArgs, /*IsMemberFunction=*/false, 629 TheCall->getRParenLoc(), 630 TheCall->getCallee()->getSourceRange(), CallType); 631 632 return false; 633} 634 635/// Checks function calls when a FunctionDecl or a NamedDecl is not available, 636/// such as function pointers returned from functions. 637bool Sema::CheckOtherCall(CallExpr *TheCall, const FunctionProtoType *Proto) { 638 VariadicCallType CallType = getVariadicCallType(/*FDecl=*/0, Proto, 639 TheCall->getCallee()); 640 unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0; 641 642 checkCall(/*FDecl=*/0, 643 llvm::makeArrayRef<const Expr *>(TheCall->getArgs(), 644 TheCall->getNumArgs()), 645 NumProtoArgs, /*IsMemberFunction=*/false, 646 TheCall->getRParenLoc(), 647 TheCall->getCallee()->getSourceRange(), CallType); 648 649 return false; 650} 651 652ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult, 653 AtomicExpr::AtomicOp Op) { 654 CallExpr *TheCall = cast<CallExpr>(TheCallResult.get()); 655 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 656 657 // All these operations take one of the following forms: 658 enum { 659 // C __c11_atomic_init(A *, C) 660 Init, 661 // C __c11_atomic_load(A *, int) 662 Load, 663 // void __atomic_load(A *, CP, int) 664 Copy, 665 // C __c11_atomic_add(A *, M, int) 666 Arithmetic, 667 // C __atomic_exchange_n(A *, CP, int) 668 Xchg, 669 // void __atomic_exchange(A *, C *, CP, int) 670 GNUXchg, 671 // bool __c11_atomic_compare_exchange_strong(A *, C *, CP, int, int) 672 C11CmpXchg, 673 // bool __atomic_compare_exchange(A *, C *, CP, bool, int, int) 674 GNUCmpXchg 675 } Form = Init; 676 const unsigned NumArgs[] = { 2, 2, 3, 3, 3, 4, 5, 6 }; 677 const unsigned NumVals[] = { 1, 0, 1, 1, 1, 2, 2, 3 }; 678 // where: 679 // C is an appropriate type, 680 // A is volatile _Atomic(C) for __c11 builtins and is C for GNU builtins, 681 // CP is C for __c11 builtins and GNU _n builtins and is C * otherwise, 682 // M is C if C is an integer, and ptrdiff_t if C is a pointer, and 683 // the int parameters are for orderings. 684 685 assert(AtomicExpr::AO__c11_atomic_init == 0 && 686 AtomicExpr::AO__c11_atomic_fetch_xor + 1 == AtomicExpr::AO__atomic_load 687 && "need to update code for modified C11 atomics"); 688 bool IsC11 = Op >= AtomicExpr::AO__c11_atomic_init && 689 Op <= AtomicExpr::AO__c11_atomic_fetch_xor; 690 bool IsN = Op == AtomicExpr::AO__atomic_load_n || 691 Op == AtomicExpr::AO__atomic_store_n || 692 Op == AtomicExpr::AO__atomic_exchange_n || 693 Op == AtomicExpr::AO__atomic_compare_exchange_n; 694 bool IsAddSub = false; 695 696 switch (Op) { 697 case AtomicExpr::AO__c11_atomic_init: 698 Form = Init; 699 break; 700 701 case AtomicExpr::AO__c11_atomic_load: 702 case AtomicExpr::AO__atomic_load_n: 703 Form = Load; 704 break; 705 706 case AtomicExpr::AO__c11_atomic_store: 707 case AtomicExpr::AO__atomic_load: 708 case AtomicExpr::AO__atomic_store: 709 case AtomicExpr::AO__atomic_store_n: 710 Form = Copy; 711 break; 712 713 case AtomicExpr::AO__c11_atomic_fetch_add: 714 case AtomicExpr::AO__c11_atomic_fetch_sub: 715 case AtomicExpr::AO__atomic_fetch_add: 716 case AtomicExpr::AO__atomic_fetch_sub: 717 case AtomicExpr::AO__atomic_add_fetch: 718 case AtomicExpr::AO__atomic_sub_fetch: 719 IsAddSub = true; 720 // Fall through. 721 case AtomicExpr::AO__c11_atomic_fetch_and: 722 case AtomicExpr::AO__c11_atomic_fetch_or: 723 case AtomicExpr::AO__c11_atomic_fetch_xor: 724 case AtomicExpr::AO__atomic_fetch_and: 725 case AtomicExpr::AO__atomic_fetch_or: 726 case AtomicExpr::AO__atomic_fetch_xor: 727 case AtomicExpr::AO__atomic_fetch_nand: 728 case AtomicExpr::AO__atomic_and_fetch: 729 case AtomicExpr::AO__atomic_or_fetch: 730 case AtomicExpr::AO__atomic_xor_fetch: 731 case AtomicExpr::AO__atomic_nand_fetch: 732 Form = Arithmetic; 733 break; 734 735 case AtomicExpr::AO__c11_atomic_exchange: 736 case AtomicExpr::AO__atomic_exchange_n: 737 Form = Xchg; 738 break; 739 740 case AtomicExpr::AO__atomic_exchange: 741 Form = GNUXchg; 742 break; 743 744 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 745 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 746 Form = C11CmpXchg; 747 break; 748 749 case AtomicExpr::AO__atomic_compare_exchange: 750 case AtomicExpr::AO__atomic_compare_exchange_n: 751 Form = GNUCmpXchg; 752 break; 753 } 754 755 // Check we have the right number of arguments. 756 if (TheCall->getNumArgs() < NumArgs[Form]) { 757 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 758 << 0 << NumArgs[Form] << TheCall->getNumArgs() 759 << TheCall->getCallee()->getSourceRange(); 760 return ExprError(); 761 } else if (TheCall->getNumArgs() > NumArgs[Form]) { 762 Diag(TheCall->getArg(NumArgs[Form])->getLocStart(), 763 diag::err_typecheck_call_too_many_args) 764 << 0 << NumArgs[Form] << TheCall->getNumArgs() 765 << TheCall->getCallee()->getSourceRange(); 766 return ExprError(); 767 } 768 769 // Inspect the first argument of the atomic operation. 770 Expr *Ptr = TheCall->getArg(0); 771 Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get(); 772 const PointerType *pointerType = Ptr->getType()->getAs<PointerType>(); 773 if (!pointerType) { 774 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 775 << Ptr->getType() << Ptr->getSourceRange(); 776 return ExprError(); 777 } 778 779 // For a __c11 builtin, this should be a pointer to an _Atomic type. 780 QualType AtomTy = pointerType->getPointeeType(); // 'A' 781 QualType ValType = AtomTy; // 'C' 782 if (IsC11) { 783 if (!AtomTy->isAtomicType()) { 784 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic) 785 << Ptr->getType() << Ptr->getSourceRange(); 786 return ExprError(); 787 } 788 if (AtomTy.isConstQualified()) { 789 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_atomic) 790 << Ptr->getType() << Ptr->getSourceRange(); 791 return ExprError(); 792 } 793 ValType = AtomTy->getAs<AtomicType>()->getValueType(); 794 } 795 796 // For an arithmetic operation, the implied arithmetic must be well-formed. 797 if (Form == Arithmetic) { 798 // gcc does not enforce these rules for GNU atomics, but we do so for sanity. 799 if (IsAddSub && !ValType->isIntegerType() && !ValType->isPointerType()) { 800 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 801 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 802 return ExprError(); 803 } 804 if (!IsAddSub && !ValType->isIntegerType()) { 805 Diag(DRE->getLocStart(), diag::err_atomic_op_bitwise_needs_atomic_int) 806 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 807 return ExprError(); 808 } 809 } else if (IsN && !ValType->isIntegerType() && !ValType->isPointerType()) { 810 // For __atomic_*_n operations, the value type must be a scalar integral or 811 // pointer type which is 1, 2, 4, 8 or 16 bytes in length. 812 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 813 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 814 return ExprError(); 815 } 816 817 if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context)) { 818 // For GNU atomics, require a trivially-copyable type. This is not part of 819 // the GNU atomics specification, but we enforce it for sanity. 820 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_trivial_copy) 821 << Ptr->getType() << Ptr->getSourceRange(); 822 return ExprError(); 823 } 824 825 // FIXME: For any builtin other than a load, the ValType must not be 826 // const-qualified. 827 828 switch (ValType.getObjCLifetime()) { 829 case Qualifiers::OCL_None: 830 case Qualifiers::OCL_ExplicitNone: 831 // okay 832 break; 833 834 case Qualifiers::OCL_Weak: 835 case Qualifiers::OCL_Strong: 836 case Qualifiers::OCL_Autoreleasing: 837 // FIXME: Can this happen? By this point, ValType should be known 838 // to be trivially copyable. 839 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 840 << ValType << Ptr->getSourceRange(); 841 return ExprError(); 842 } 843 844 QualType ResultType = ValType; 845 if (Form == Copy || Form == GNUXchg || Form == Init) 846 ResultType = Context.VoidTy; 847 else if (Form == C11CmpXchg || Form == GNUCmpXchg) 848 ResultType = Context.BoolTy; 849 850 // The type of a parameter passed 'by value'. In the GNU atomics, such 851 // arguments are actually passed as pointers. 852 QualType ByValType = ValType; // 'CP' 853 if (!IsC11 && !IsN) 854 ByValType = Ptr->getType(); 855 856 // The first argument --- the pointer --- has a fixed type; we 857 // deduce the types of the rest of the arguments accordingly. Walk 858 // the remaining arguments, converting them to the deduced value type. 859 for (unsigned i = 1; i != NumArgs[Form]; ++i) { 860 QualType Ty; 861 if (i < NumVals[Form] + 1) { 862 switch (i) { 863 case 1: 864 // The second argument is the non-atomic operand. For arithmetic, this 865 // is always passed by value, and for a compare_exchange it is always 866 // passed by address. For the rest, GNU uses by-address and C11 uses 867 // by-value. 868 assert(Form != Load); 869 if (Form == Init || (Form == Arithmetic && ValType->isIntegerType())) 870 Ty = ValType; 871 else if (Form == Copy || Form == Xchg) 872 Ty = ByValType; 873 else if (Form == Arithmetic) 874 Ty = Context.getPointerDiffType(); 875 else 876 Ty = Context.getPointerType(ValType.getUnqualifiedType()); 877 break; 878 case 2: 879 // The third argument to compare_exchange / GNU exchange is a 880 // (pointer to a) desired value. 881 Ty = ByValType; 882 break; 883 case 3: 884 // The fourth argument to GNU compare_exchange is a 'weak' flag. 885 Ty = Context.BoolTy; 886 break; 887 } 888 } else { 889 // The order(s) are always converted to int. 890 Ty = Context.IntTy; 891 } 892 893 InitializedEntity Entity = 894 InitializedEntity::InitializeParameter(Context, Ty, false); 895 ExprResult Arg = TheCall->getArg(i); 896 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 897 if (Arg.isInvalid()) 898 return true; 899 TheCall->setArg(i, Arg.get()); 900 } 901 902 // Permute the arguments into a 'consistent' order. 903 SmallVector<Expr*, 5> SubExprs; 904 SubExprs.push_back(Ptr); 905 switch (Form) { 906 case Init: 907 // Note, AtomicExpr::getVal1() has a special case for this atomic. 908 SubExprs.push_back(TheCall->getArg(1)); // Val1 909 break; 910 case Load: 911 SubExprs.push_back(TheCall->getArg(1)); // Order 912 break; 913 case Copy: 914 case Arithmetic: 915 case Xchg: 916 SubExprs.push_back(TheCall->getArg(2)); // Order 917 SubExprs.push_back(TheCall->getArg(1)); // Val1 918 break; 919 case GNUXchg: 920 // Note, AtomicExpr::getVal2() has a special case for this atomic. 921 SubExprs.push_back(TheCall->getArg(3)); // Order 922 SubExprs.push_back(TheCall->getArg(1)); // Val1 923 SubExprs.push_back(TheCall->getArg(2)); // Val2 924 break; 925 case C11CmpXchg: 926 SubExprs.push_back(TheCall->getArg(3)); // Order 927 SubExprs.push_back(TheCall->getArg(1)); // Val1 928 SubExprs.push_back(TheCall->getArg(4)); // OrderFail 929 SubExprs.push_back(TheCall->getArg(2)); // Val2 930 break; 931 case GNUCmpXchg: 932 SubExprs.push_back(TheCall->getArg(4)); // Order 933 SubExprs.push_back(TheCall->getArg(1)); // Val1 934 SubExprs.push_back(TheCall->getArg(5)); // OrderFail 935 SubExprs.push_back(TheCall->getArg(2)); // Val2 936 SubExprs.push_back(TheCall->getArg(3)); // Weak 937 break; 938 } 939 940 AtomicExpr *AE = new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(), 941 SubExprs, ResultType, Op, 942 TheCall->getRParenLoc()); 943 944 if ((Op == AtomicExpr::AO__c11_atomic_load || 945 (Op == AtomicExpr::AO__c11_atomic_store)) && 946 Context.AtomicUsesUnsupportedLibcall(AE)) 947 Diag(AE->getLocStart(), diag::err_atomic_load_store_uses_lib) << 948 ((Op == AtomicExpr::AO__c11_atomic_load) ? 0 : 1); 949 950 return Owned(AE); 951} 952 953 954/// checkBuiltinArgument - Given a call to a builtin function, perform 955/// normal type-checking on the given argument, updating the call in 956/// place. This is useful when a builtin function requires custom 957/// type-checking for some of its arguments but not necessarily all of 958/// them. 959/// 960/// Returns true on error. 961static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) { 962 FunctionDecl *Fn = E->getDirectCallee(); 963 assert(Fn && "builtin call without direct callee!"); 964 965 ParmVarDecl *Param = Fn->getParamDecl(ArgIndex); 966 InitializedEntity Entity = 967 InitializedEntity::InitializeParameter(S.Context, Param); 968 969 ExprResult Arg = E->getArg(0); 970 Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg); 971 if (Arg.isInvalid()) 972 return true; 973 974 E->setArg(ArgIndex, Arg.take()); 975 return false; 976} 977 978/// SemaBuiltinAtomicOverloaded - We have a call to a function like 979/// __sync_fetch_and_add, which is an overloaded function based on the pointer 980/// type of its first argument. The main ActOnCallExpr routines have already 981/// promoted the types of arguments because all of these calls are prototyped as 982/// void(...). 983/// 984/// This function goes through and does final semantic checking for these 985/// builtins, 986ExprResult 987Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) { 988 CallExpr *TheCall = (CallExpr *)TheCallResult.get(); 989 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 990 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 991 992 // Ensure that we have at least one argument to do type inference from. 993 if (TheCall->getNumArgs() < 1) { 994 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 995 << 0 << 1 << TheCall->getNumArgs() 996 << TheCall->getCallee()->getSourceRange(); 997 return ExprError(); 998 } 999 1000 // Inspect the first argument of the atomic builtin. This should always be 1001 // a pointer type, whose element is an integral scalar or pointer type. 1002 // Because it is a pointer type, we don't have to worry about any implicit 1003 // casts here. 1004 // FIXME: We don't allow floating point scalars as input. 1005 Expr *FirstArg = TheCall->getArg(0); 1006 ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg); 1007 if (FirstArgResult.isInvalid()) 1008 return ExprError(); 1009 FirstArg = FirstArgResult.take(); 1010 TheCall->setArg(0, FirstArg); 1011 1012 const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>(); 1013 if (!pointerType) { 1014 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 1015 << FirstArg->getType() << FirstArg->getSourceRange(); 1016 return ExprError(); 1017 } 1018 1019 QualType ValType = pointerType->getPointeeType(); 1020 if (!ValType->isIntegerType() && !ValType->isAnyPointerType() && 1021 !ValType->isBlockPointerType()) { 1022 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr) 1023 << FirstArg->getType() << FirstArg->getSourceRange(); 1024 return ExprError(); 1025 } 1026 1027 switch (ValType.getObjCLifetime()) { 1028 case Qualifiers::OCL_None: 1029 case Qualifiers::OCL_ExplicitNone: 1030 // okay 1031 break; 1032 1033 case Qualifiers::OCL_Weak: 1034 case Qualifiers::OCL_Strong: 1035 case Qualifiers::OCL_Autoreleasing: 1036 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 1037 << ValType << FirstArg->getSourceRange(); 1038 return ExprError(); 1039 } 1040 1041 // Strip any qualifiers off ValType. 1042 ValType = ValType.getUnqualifiedType(); 1043 1044 // The majority of builtins return a value, but a few have special return 1045 // types, so allow them to override appropriately below. 1046 QualType ResultType = ValType; 1047 1048 // We need to figure out which concrete builtin this maps onto. For example, 1049 // __sync_fetch_and_add with a 2 byte object turns into 1050 // __sync_fetch_and_add_2. 1051#define BUILTIN_ROW(x) \ 1052 { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \ 1053 Builtin::BI##x##_8, Builtin::BI##x##_16 } 1054 1055 static const unsigned BuiltinIndices[][5] = { 1056 BUILTIN_ROW(__sync_fetch_and_add), 1057 BUILTIN_ROW(__sync_fetch_and_sub), 1058 BUILTIN_ROW(__sync_fetch_and_or), 1059 BUILTIN_ROW(__sync_fetch_and_and), 1060 BUILTIN_ROW(__sync_fetch_and_xor), 1061 1062 BUILTIN_ROW(__sync_add_and_fetch), 1063 BUILTIN_ROW(__sync_sub_and_fetch), 1064 BUILTIN_ROW(__sync_and_and_fetch), 1065 BUILTIN_ROW(__sync_or_and_fetch), 1066 BUILTIN_ROW(__sync_xor_and_fetch), 1067 1068 BUILTIN_ROW(__sync_val_compare_and_swap), 1069 BUILTIN_ROW(__sync_bool_compare_and_swap), 1070 BUILTIN_ROW(__sync_lock_test_and_set), 1071 BUILTIN_ROW(__sync_lock_release), 1072 BUILTIN_ROW(__sync_swap) 1073 }; 1074#undef BUILTIN_ROW 1075 1076 // Determine the index of the size. 1077 unsigned SizeIndex; 1078 switch (Context.getTypeSizeInChars(ValType).getQuantity()) { 1079 case 1: SizeIndex = 0; break; 1080 case 2: SizeIndex = 1; break; 1081 case 4: SizeIndex = 2; break; 1082 case 8: SizeIndex = 3; break; 1083 case 16: SizeIndex = 4; break; 1084 default: 1085 Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size) 1086 << FirstArg->getType() << FirstArg->getSourceRange(); 1087 return ExprError(); 1088 } 1089 1090 // Each of these builtins has one pointer argument, followed by some number of 1091 // values (0, 1 or 2) followed by a potentially empty varags list of stuff 1092 // that we ignore. Find out which row of BuiltinIndices to read from as well 1093 // as the number of fixed args. 1094 unsigned BuiltinID = FDecl->getBuiltinID(); 1095 unsigned BuiltinIndex, NumFixed = 1; 1096 switch (BuiltinID) { 1097 default: llvm_unreachable("Unknown overloaded atomic builtin!"); 1098 case Builtin::BI__sync_fetch_and_add: 1099 case Builtin::BI__sync_fetch_and_add_1: 1100 case Builtin::BI__sync_fetch_and_add_2: 1101 case Builtin::BI__sync_fetch_and_add_4: 1102 case Builtin::BI__sync_fetch_and_add_8: 1103 case Builtin::BI__sync_fetch_and_add_16: 1104 BuiltinIndex = 0; 1105 break; 1106 1107 case Builtin::BI__sync_fetch_and_sub: 1108 case Builtin::BI__sync_fetch_and_sub_1: 1109 case Builtin::BI__sync_fetch_and_sub_2: 1110 case Builtin::BI__sync_fetch_and_sub_4: 1111 case Builtin::BI__sync_fetch_and_sub_8: 1112 case Builtin::BI__sync_fetch_and_sub_16: 1113 BuiltinIndex = 1; 1114 break; 1115 1116 case Builtin::BI__sync_fetch_and_or: 1117 case Builtin::BI__sync_fetch_and_or_1: 1118 case Builtin::BI__sync_fetch_and_or_2: 1119 case Builtin::BI__sync_fetch_and_or_4: 1120 case Builtin::BI__sync_fetch_and_or_8: 1121 case Builtin::BI__sync_fetch_and_or_16: 1122 BuiltinIndex = 2; 1123 break; 1124 1125 case Builtin::BI__sync_fetch_and_and: 1126 case Builtin::BI__sync_fetch_and_and_1: 1127 case Builtin::BI__sync_fetch_and_and_2: 1128 case Builtin::BI__sync_fetch_and_and_4: 1129 case Builtin::BI__sync_fetch_and_and_8: 1130 case Builtin::BI__sync_fetch_and_and_16: 1131 BuiltinIndex = 3; 1132 break; 1133 1134 case Builtin::BI__sync_fetch_and_xor: 1135 case Builtin::BI__sync_fetch_and_xor_1: 1136 case Builtin::BI__sync_fetch_and_xor_2: 1137 case Builtin::BI__sync_fetch_and_xor_4: 1138 case Builtin::BI__sync_fetch_and_xor_8: 1139 case Builtin::BI__sync_fetch_and_xor_16: 1140 BuiltinIndex = 4; 1141 break; 1142 1143 case Builtin::BI__sync_add_and_fetch: 1144 case Builtin::BI__sync_add_and_fetch_1: 1145 case Builtin::BI__sync_add_and_fetch_2: 1146 case Builtin::BI__sync_add_and_fetch_4: 1147 case Builtin::BI__sync_add_and_fetch_8: 1148 case Builtin::BI__sync_add_and_fetch_16: 1149 BuiltinIndex = 5; 1150 break; 1151 1152 case Builtin::BI__sync_sub_and_fetch: 1153 case Builtin::BI__sync_sub_and_fetch_1: 1154 case Builtin::BI__sync_sub_and_fetch_2: 1155 case Builtin::BI__sync_sub_and_fetch_4: 1156 case Builtin::BI__sync_sub_and_fetch_8: 1157 case Builtin::BI__sync_sub_and_fetch_16: 1158 BuiltinIndex = 6; 1159 break; 1160 1161 case Builtin::BI__sync_and_and_fetch: 1162 case Builtin::BI__sync_and_and_fetch_1: 1163 case Builtin::BI__sync_and_and_fetch_2: 1164 case Builtin::BI__sync_and_and_fetch_4: 1165 case Builtin::BI__sync_and_and_fetch_8: 1166 case Builtin::BI__sync_and_and_fetch_16: 1167 BuiltinIndex = 7; 1168 break; 1169 1170 case Builtin::BI__sync_or_and_fetch: 1171 case Builtin::BI__sync_or_and_fetch_1: 1172 case Builtin::BI__sync_or_and_fetch_2: 1173 case Builtin::BI__sync_or_and_fetch_4: 1174 case Builtin::BI__sync_or_and_fetch_8: 1175 case Builtin::BI__sync_or_and_fetch_16: 1176 BuiltinIndex = 8; 1177 break; 1178 1179 case Builtin::BI__sync_xor_and_fetch: 1180 case Builtin::BI__sync_xor_and_fetch_1: 1181 case Builtin::BI__sync_xor_and_fetch_2: 1182 case Builtin::BI__sync_xor_and_fetch_4: 1183 case Builtin::BI__sync_xor_and_fetch_8: 1184 case Builtin::BI__sync_xor_and_fetch_16: 1185 BuiltinIndex = 9; 1186 break; 1187 1188 case Builtin::BI__sync_val_compare_and_swap: 1189 case Builtin::BI__sync_val_compare_and_swap_1: 1190 case Builtin::BI__sync_val_compare_and_swap_2: 1191 case Builtin::BI__sync_val_compare_and_swap_4: 1192 case Builtin::BI__sync_val_compare_and_swap_8: 1193 case Builtin::BI__sync_val_compare_and_swap_16: 1194 BuiltinIndex = 10; 1195 NumFixed = 2; 1196 break; 1197 1198 case Builtin::BI__sync_bool_compare_and_swap: 1199 case Builtin::BI__sync_bool_compare_and_swap_1: 1200 case Builtin::BI__sync_bool_compare_and_swap_2: 1201 case Builtin::BI__sync_bool_compare_and_swap_4: 1202 case Builtin::BI__sync_bool_compare_and_swap_8: 1203 case Builtin::BI__sync_bool_compare_and_swap_16: 1204 BuiltinIndex = 11; 1205 NumFixed = 2; 1206 ResultType = Context.BoolTy; 1207 break; 1208 1209 case Builtin::BI__sync_lock_test_and_set: 1210 case Builtin::BI__sync_lock_test_and_set_1: 1211 case Builtin::BI__sync_lock_test_and_set_2: 1212 case Builtin::BI__sync_lock_test_and_set_4: 1213 case Builtin::BI__sync_lock_test_and_set_8: 1214 case Builtin::BI__sync_lock_test_and_set_16: 1215 BuiltinIndex = 12; 1216 break; 1217 1218 case Builtin::BI__sync_lock_release: 1219 case Builtin::BI__sync_lock_release_1: 1220 case Builtin::BI__sync_lock_release_2: 1221 case Builtin::BI__sync_lock_release_4: 1222 case Builtin::BI__sync_lock_release_8: 1223 case Builtin::BI__sync_lock_release_16: 1224 BuiltinIndex = 13; 1225 NumFixed = 0; 1226 ResultType = Context.VoidTy; 1227 break; 1228 1229 case Builtin::BI__sync_swap: 1230 case Builtin::BI__sync_swap_1: 1231 case Builtin::BI__sync_swap_2: 1232 case Builtin::BI__sync_swap_4: 1233 case Builtin::BI__sync_swap_8: 1234 case Builtin::BI__sync_swap_16: 1235 BuiltinIndex = 14; 1236 break; 1237 } 1238 1239 // Now that we know how many fixed arguments we expect, first check that we 1240 // have at least that many. 1241 if (TheCall->getNumArgs() < 1+NumFixed) { 1242 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 1243 << 0 << 1+NumFixed << TheCall->getNumArgs() 1244 << TheCall->getCallee()->getSourceRange(); 1245 return ExprError(); 1246 } 1247 1248 // Get the decl for the concrete builtin from this, we can tell what the 1249 // concrete integer type we should convert to is. 1250 unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex]; 1251 const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID); 1252 FunctionDecl *NewBuiltinDecl; 1253 if (NewBuiltinID == BuiltinID) 1254 NewBuiltinDecl = FDecl; 1255 else { 1256 // Perform builtin lookup to avoid redeclaring it. 1257 DeclarationName DN(&Context.Idents.get(NewBuiltinName)); 1258 LookupResult Res(*this, DN, DRE->getLocStart(), LookupOrdinaryName); 1259 LookupName(Res, TUScope, /*AllowBuiltinCreation=*/true); 1260 assert(Res.getFoundDecl()); 1261 NewBuiltinDecl = dyn_cast<FunctionDecl>(Res.getFoundDecl()); 1262 if (NewBuiltinDecl == 0) 1263 return ExprError(); 1264 } 1265 1266 // The first argument --- the pointer --- has a fixed type; we 1267 // deduce the types of the rest of the arguments accordingly. Walk 1268 // the remaining arguments, converting them to the deduced value type. 1269 for (unsigned i = 0; i != NumFixed; ++i) { 1270 ExprResult Arg = TheCall->getArg(i+1); 1271 1272 // GCC does an implicit conversion to the pointer or integer ValType. This 1273 // can fail in some cases (1i -> int**), check for this error case now. 1274 // Initialize the argument. 1275 InitializedEntity Entity = InitializedEntity::InitializeParameter(Context, 1276 ValType, /*consume*/ false); 1277 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 1278 if (Arg.isInvalid()) 1279 return ExprError(); 1280 1281 // Okay, we have something that *can* be converted to the right type. Check 1282 // to see if there is a potentially weird extension going on here. This can 1283 // happen when you do an atomic operation on something like an char* and 1284 // pass in 42. The 42 gets converted to char. This is even more strange 1285 // for things like 45.123 -> char, etc. 1286 // FIXME: Do this check. 1287 TheCall->setArg(i+1, Arg.take()); 1288 } 1289 1290 ASTContext& Context = this->getASTContext(); 1291 1292 // Create a new DeclRefExpr to refer to the new decl. 1293 DeclRefExpr* NewDRE = DeclRefExpr::Create( 1294 Context, 1295 DRE->getQualifierLoc(), 1296 SourceLocation(), 1297 NewBuiltinDecl, 1298 /*enclosing*/ false, 1299 DRE->getLocation(), 1300 Context.BuiltinFnTy, 1301 DRE->getValueKind()); 1302 1303 // Set the callee in the CallExpr. 1304 // FIXME: This loses syntactic information. 1305 QualType CalleePtrTy = Context.getPointerType(NewBuiltinDecl->getType()); 1306 ExprResult PromotedCall = ImpCastExprToType(NewDRE, CalleePtrTy, 1307 CK_BuiltinFnToFnPtr); 1308 TheCall->setCallee(PromotedCall.take()); 1309 1310 // Change the result type of the call to match the original value type. This 1311 // is arbitrary, but the codegen for these builtins ins design to handle it 1312 // gracefully. 1313 TheCall->setType(ResultType); 1314 1315 return TheCallResult; 1316} 1317 1318/// CheckObjCString - Checks that the argument to the builtin 1319/// CFString constructor is correct 1320/// Note: It might also make sense to do the UTF-16 conversion here (would 1321/// simplify the backend). 1322bool Sema::CheckObjCString(Expr *Arg) { 1323 Arg = Arg->IgnoreParenCasts(); 1324 StringLiteral *Literal = dyn_cast<StringLiteral>(Arg); 1325 1326 if (!Literal || !Literal->isAscii()) { 1327 Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant) 1328 << Arg->getSourceRange(); 1329 return true; 1330 } 1331 1332 if (Literal->containsNonAsciiOrNull()) { 1333 StringRef String = Literal->getString(); 1334 unsigned NumBytes = String.size(); 1335 SmallVector<UTF16, 128> ToBuf(NumBytes); 1336 const UTF8 *FromPtr = (const UTF8 *)String.data(); 1337 UTF16 *ToPtr = &ToBuf[0]; 1338 1339 ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, 1340 &ToPtr, ToPtr + NumBytes, 1341 strictConversion); 1342 // Check for conversion failure. 1343 if (Result != conversionOK) 1344 Diag(Arg->getLocStart(), 1345 diag::warn_cfstring_truncated) << Arg->getSourceRange(); 1346 } 1347 return false; 1348} 1349 1350/// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity. 1351/// Emit an error and return true on failure, return false on success. 1352bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) { 1353 Expr *Fn = TheCall->getCallee(); 1354 if (TheCall->getNumArgs() > 2) { 1355 Diag(TheCall->getArg(2)->getLocStart(), 1356 diag::err_typecheck_call_too_many_args) 1357 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1358 << Fn->getSourceRange() 1359 << SourceRange(TheCall->getArg(2)->getLocStart(), 1360 (*(TheCall->arg_end()-1))->getLocEnd()); 1361 return true; 1362 } 1363 1364 if (TheCall->getNumArgs() < 2) { 1365 return Diag(TheCall->getLocEnd(), 1366 diag::err_typecheck_call_too_few_args_at_least) 1367 << 0 /*function call*/ << 2 << TheCall->getNumArgs(); 1368 } 1369 1370 // Type-check the first argument normally. 1371 if (checkBuiltinArgument(*this, TheCall, 0)) 1372 return true; 1373 1374 // Determine whether the current function is variadic or not. 1375 BlockScopeInfo *CurBlock = getCurBlock(); 1376 bool isVariadic; 1377 if (CurBlock) 1378 isVariadic = CurBlock->TheDecl->isVariadic(); 1379 else if (FunctionDecl *FD = getCurFunctionDecl()) 1380 isVariadic = FD->isVariadic(); 1381 else 1382 isVariadic = getCurMethodDecl()->isVariadic(); 1383 1384 if (!isVariadic) { 1385 Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function); 1386 return true; 1387 } 1388 1389 // Verify that the second argument to the builtin is the last argument of the 1390 // current function or method. 1391 bool SecondArgIsLastNamedArgument = false; 1392 const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts(); 1393 1394 // These are valid if SecondArgIsLastNamedArgument is false after the next 1395 // block. 1396 QualType Type; 1397 SourceLocation ParamLoc; 1398 1399 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) { 1400 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) { 1401 // FIXME: This isn't correct for methods (results in bogus warning). 1402 // Get the last formal in the current function. 1403 const ParmVarDecl *LastArg; 1404 if (CurBlock) 1405 LastArg = *(CurBlock->TheDecl->param_end()-1); 1406 else if (FunctionDecl *FD = getCurFunctionDecl()) 1407 LastArg = *(FD->param_end()-1); 1408 else 1409 LastArg = *(getCurMethodDecl()->param_end()-1); 1410 SecondArgIsLastNamedArgument = PV == LastArg; 1411 1412 Type = PV->getType(); 1413 ParamLoc = PV->getLocation(); 1414 } 1415 } 1416 1417 if (!SecondArgIsLastNamedArgument) 1418 Diag(TheCall->getArg(1)->getLocStart(), 1419 diag::warn_second_parameter_of_va_start_not_last_named_argument); 1420 else if (Type->isReferenceType()) { 1421 Diag(Arg->getLocStart(), 1422 diag::warn_va_start_of_reference_type_is_undefined); 1423 Diag(ParamLoc, diag::note_parameter_type) << Type; 1424 } 1425 1426 return false; 1427} 1428 1429/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and 1430/// friends. This is declared to take (...), so we have to check everything. 1431bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) { 1432 if (TheCall->getNumArgs() < 2) 1433 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 1434 << 0 << 2 << TheCall->getNumArgs()/*function call*/; 1435 if (TheCall->getNumArgs() > 2) 1436 return Diag(TheCall->getArg(2)->getLocStart(), 1437 diag::err_typecheck_call_too_many_args) 1438 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1439 << SourceRange(TheCall->getArg(2)->getLocStart(), 1440 (*(TheCall->arg_end()-1))->getLocEnd()); 1441 1442 ExprResult OrigArg0 = TheCall->getArg(0); 1443 ExprResult OrigArg1 = TheCall->getArg(1); 1444 1445 // Do standard promotions between the two arguments, returning their common 1446 // type. 1447 QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false); 1448 if (OrigArg0.isInvalid() || OrigArg1.isInvalid()) 1449 return true; 1450 1451 // Make sure any conversions are pushed back into the call; this is 1452 // type safe since unordered compare builtins are declared as "_Bool 1453 // foo(...)". 1454 TheCall->setArg(0, OrigArg0.get()); 1455 TheCall->setArg(1, OrigArg1.get()); 1456 1457 if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent()) 1458 return false; 1459 1460 // If the common type isn't a real floating type, then the arguments were 1461 // invalid for this operation. 1462 if (Res.isNull() || !Res->isRealFloatingType()) 1463 return Diag(OrigArg0.get()->getLocStart(), 1464 diag::err_typecheck_call_invalid_ordered_compare) 1465 << OrigArg0.get()->getType() << OrigArg1.get()->getType() 1466 << SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd()); 1467 1468 return false; 1469} 1470 1471/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like 1472/// __builtin_isnan and friends. This is declared to take (...), so we have 1473/// to check everything. We expect the last argument to be a floating point 1474/// value. 1475bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) { 1476 if (TheCall->getNumArgs() < NumArgs) 1477 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 1478 << 0 << NumArgs << TheCall->getNumArgs()/*function call*/; 1479 if (TheCall->getNumArgs() > NumArgs) 1480 return Diag(TheCall->getArg(NumArgs)->getLocStart(), 1481 diag::err_typecheck_call_too_many_args) 1482 << 0 /*function call*/ << NumArgs << TheCall->getNumArgs() 1483 << SourceRange(TheCall->getArg(NumArgs)->getLocStart(), 1484 (*(TheCall->arg_end()-1))->getLocEnd()); 1485 1486 Expr *OrigArg = TheCall->getArg(NumArgs-1); 1487 1488 if (OrigArg->isTypeDependent()) 1489 return false; 1490 1491 // This operation requires a non-_Complex floating-point number. 1492 if (!OrigArg->getType()->isRealFloatingType()) 1493 return Diag(OrigArg->getLocStart(), 1494 diag::err_typecheck_call_invalid_unary_fp) 1495 << OrigArg->getType() << OrigArg->getSourceRange(); 1496 1497 // If this is an implicit conversion from float -> double, remove it. 1498 if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) { 1499 Expr *CastArg = Cast->getSubExpr(); 1500 if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) { 1501 assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) && 1502 "promotion from float to double is the only expected cast here"); 1503 Cast->setSubExpr(0); 1504 TheCall->setArg(NumArgs-1, CastArg); 1505 } 1506 } 1507 1508 return false; 1509} 1510 1511/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector. 1512// This is declared to take (...), so we have to check everything. 1513ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) { 1514 if (TheCall->getNumArgs() < 2) 1515 return ExprError(Diag(TheCall->getLocEnd(), 1516 diag::err_typecheck_call_too_few_args_at_least) 1517 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1518 << TheCall->getSourceRange()); 1519 1520 // Determine which of the following types of shufflevector we're checking: 1521 // 1) unary, vector mask: (lhs, mask) 1522 // 2) binary, vector mask: (lhs, rhs, mask) 1523 // 3) binary, scalar mask: (lhs, rhs, index, ..., index) 1524 QualType resType = TheCall->getArg(0)->getType(); 1525 unsigned numElements = 0; 1526 1527 if (!TheCall->getArg(0)->isTypeDependent() && 1528 !TheCall->getArg(1)->isTypeDependent()) { 1529 QualType LHSType = TheCall->getArg(0)->getType(); 1530 QualType RHSType = TheCall->getArg(1)->getType(); 1531 1532 if (!LHSType->isVectorType() || !RHSType->isVectorType()) { 1533 Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector) 1534 << SourceRange(TheCall->getArg(0)->getLocStart(), 1535 TheCall->getArg(1)->getLocEnd()); 1536 return ExprError(); 1537 } 1538 1539 numElements = LHSType->getAs<VectorType>()->getNumElements(); 1540 unsigned numResElements = TheCall->getNumArgs() - 2; 1541 1542 // Check to see if we have a call with 2 vector arguments, the unary shuffle 1543 // with mask. If so, verify that RHS is an integer vector type with the 1544 // same number of elts as lhs. 1545 if (TheCall->getNumArgs() == 2) { 1546 if (!RHSType->hasIntegerRepresentation() || 1547 RHSType->getAs<VectorType>()->getNumElements() != numElements) 1548 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 1549 << SourceRange(TheCall->getArg(1)->getLocStart(), 1550 TheCall->getArg(1)->getLocEnd()); 1551 numResElements = numElements; 1552 } 1553 else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) { 1554 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 1555 << SourceRange(TheCall->getArg(0)->getLocStart(), 1556 TheCall->getArg(1)->getLocEnd()); 1557 return ExprError(); 1558 } else if (numElements != numResElements) { 1559 QualType eltType = LHSType->getAs<VectorType>()->getElementType(); 1560 resType = Context.getVectorType(eltType, numResElements, 1561 VectorType::GenericVector); 1562 } 1563 } 1564 1565 for (unsigned i = 2; i < TheCall->getNumArgs(); i++) { 1566 if (TheCall->getArg(i)->isTypeDependent() || 1567 TheCall->getArg(i)->isValueDependent()) 1568 continue; 1569 1570 llvm::APSInt Result(32); 1571 if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context)) 1572 return ExprError(Diag(TheCall->getLocStart(), 1573 diag::err_shufflevector_nonconstant_argument) 1574 << TheCall->getArg(i)->getSourceRange()); 1575 1576 if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2) 1577 return ExprError(Diag(TheCall->getLocStart(), 1578 diag::err_shufflevector_argument_too_large) 1579 << TheCall->getArg(i)->getSourceRange()); 1580 } 1581 1582 SmallVector<Expr*, 32> exprs; 1583 1584 for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) { 1585 exprs.push_back(TheCall->getArg(i)); 1586 TheCall->setArg(i, 0); 1587 } 1588 1589 return Owned(new (Context) ShuffleVectorExpr(Context, exprs, resType, 1590 TheCall->getCallee()->getLocStart(), 1591 TheCall->getRParenLoc())); 1592} 1593 1594/// SemaBuiltinPrefetch - Handle __builtin_prefetch. 1595// This is declared to take (const void*, ...) and can take two 1596// optional constant int args. 1597bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) { 1598 unsigned NumArgs = TheCall->getNumArgs(); 1599 1600 if (NumArgs > 3) 1601 return Diag(TheCall->getLocEnd(), 1602 diag::err_typecheck_call_too_many_args_at_most) 1603 << 0 /*function call*/ << 3 << NumArgs 1604 << TheCall->getSourceRange(); 1605 1606 // Argument 0 is checked for us and the remaining arguments must be 1607 // constant integers. 1608 for (unsigned i = 1; i != NumArgs; ++i) { 1609 Expr *Arg = TheCall->getArg(i); 1610 1611 // We can't check the value of a dependent argument. 1612 if (Arg->isTypeDependent() || Arg->isValueDependent()) 1613 continue; 1614 1615 llvm::APSInt Result; 1616 if (SemaBuiltinConstantArg(TheCall, i, Result)) 1617 return true; 1618 1619 // FIXME: gcc issues a warning and rewrites these to 0. These 1620 // seems especially odd for the third argument since the default 1621 // is 3. 1622 if (i == 1) { 1623 if (Result.getLimitedValue() > 1) 1624 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1625 << "0" << "1" << Arg->getSourceRange(); 1626 } else { 1627 if (Result.getLimitedValue() > 3) 1628 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1629 << "0" << "3" << Arg->getSourceRange(); 1630 } 1631 } 1632 1633 return false; 1634} 1635 1636/// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr 1637/// TheCall is a constant expression. 1638bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum, 1639 llvm::APSInt &Result) { 1640 Expr *Arg = TheCall->getArg(ArgNum); 1641 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 1642 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 1643 1644 if (Arg->isTypeDependent() || Arg->isValueDependent()) return false; 1645 1646 if (!Arg->isIntegerConstantExpr(Result, Context)) 1647 return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type) 1648 << FDecl->getDeclName() << Arg->getSourceRange(); 1649 1650 return false; 1651} 1652 1653/// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr, 1654/// int type). This simply type checks that type is one of the defined 1655/// constants (0-3). 1656// For compatibility check 0-3, llvm only handles 0 and 2. 1657bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) { 1658 llvm::APSInt Result; 1659 1660 // We can't check the value of a dependent argument. 1661 if (TheCall->getArg(1)->isTypeDependent() || 1662 TheCall->getArg(1)->isValueDependent()) 1663 return false; 1664 1665 // Check constant-ness first. 1666 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 1667 return true; 1668 1669 Expr *Arg = TheCall->getArg(1); 1670 if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) { 1671 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1672 << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 1673 } 1674 1675 return false; 1676} 1677 1678/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val). 1679/// This checks that val is a constant 1. 1680bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) { 1681 Expr *Arg = TheCall->getArg(1); 1682 llvm::APSInt Result; 1683 1684 // TODO: This is less than ideal. Overload this to take a value. 1685 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 1686 return true; 1687 1688 if (Result != 1) 1689 return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val) 1690 << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 1691 1692 return false; 1693} 1694 1695// Determine if an expression is a string literal or constant string. 1696// If this function returns false on the arguments to a function expecting a 1697// format string, we will usually need to emit a warning. 1698// True string literals are then checked by CheckFormatString. 1699Sema::StringLiteralCheckType 1700Sema::checkFormatStringExpr(const Expr *E, ArrayRef<const Expr *> Args, 1701 bool HasVAListArg, 1702 unsigned format_idx, unsigned firstDataArg, 1703 FormatStringType Type, VariadicCallType CallType, 1704 bool inFunctionCall) { 1705 tryAgain: 1706 if (E->isTypeDependent() || E->isValueDependent()) 1707 return SLCT_NotALiteral; 1708 1709 E = E->IgnoreParenCasts(); 1710 1711 if (E->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull)) 1712 // Technically -Wformat-nonliteral does not warn about this case. 1713 // The behavior of printf and friends in this case is implementation 1714 // dependent. Ideally if the format string cannot be null then 1715 // it should have a 'nonnull' attribute in the function prototype. 1716 return SLCT_CheckedLiteral; 1717 1718 switch (E->getStmtClass()) { 1719 case Stmt::BinaryConditionalOperatorClass: 1720 case Stmt::ConditionalOperatorClass: { 1721 // The expression is a literal if both sub-expressions were, and it was 1722 // completely checked only if both sub-expressions were checked. 1723 const AbstractConditionalOperator *C = 1724 cast<AbstractConditionalOperator>(E); 1725 StringLiteralCheckType Left = 1726 checkFormatStringExpr(C->getTrueExpr(), Args, 1727 HasVAListArg, format_idx, firstDataArg, 1728 Type, CallType, inFunctionCall); 1729 if (Left == SLCT_NotALiteral) 1730 return SLCT_NotALiteral; 1731 StringLiteralCheckType Right = 1732 checkFormatStringExpr(C->getFalseExpr(), Args, 1733 HasVAListArg, format_idx, firstDataArg, 1734 Type, CallType, inFunctionCall); 1735 return Left < Right ? Left : Right; 1736 } 1737 1738 case Stmt::ImplicitCastExprClass: { 1739 E = cast<ImplicitCastExpr>(E)->getSubExpr(); 1740 goto tryAgain; 1741 } 1742 1743 case Stmt::OpaqueValueExprClass: 1744 if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) { 1745 E = src; 1746 goto tryAgain; 1747 } 1748 return SLCT_NotALiteral; 1749 1750 case Stmt::PredefinedExprClass: 1751 // While __func__, etc., are technically not string literals, they 1752 // cannot contain format specifiers and thus are not a security 1753 // liability. 1754 return SLCT_UncheckedLiteral; 1755 1756 case Stmt::DeclRefExprClass: { 1757 const DeclRefExpr *DR = cast<DeclRefExpr>(E); 1758 1759 // As an exception, do not flag errors for variables binding to 1760 // const string literals. 1761 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) { 1762 bool isConstant = false; 1763 QualType T = DR->getType(); 1764 1765 if (const ArrayType *AT = Context.getAsArrayType(T)) { 1766 isConstant = AT->getElementType().isConstant(Context); 1767 } else if (const PointerType *PT = T->getAs<PointerType>()) { 1768 isConstant = T.isConstant(Context) && 1769 PT->getPointeeType().isConstant(Context); 1770 } else if (T->isObjCObjectPointerType()) { 1771 // In ObjC, there is usually no "const ObjectPointer" type, 1772 // so don't check if the pointee type is constant. 1773 isConstant = T.isConstant(Context); 1774 } 1775 1776 if (isConstant) { 1777 if (const Expr *Init = VD->getAnyInitializer()) { 1778 // Look through initializers like const char c[] = { "foo" } 1779 if (const InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) { 1780 if (InitList->isStringLiteralInit()) 1781 Init = InitList->getInit(0)->IgnoreParenImpCasts(); 1782 } 1783 return checkFormatStringExpr(Init, Args, 1784 HasVAListArg, format_idx, 1785 firstDataArg, Type, CallType, 1786 /*inFunctionCall*/false); 1787 } 1788 } 1789 1790 // For vprintf* functions (i.e., HasVAListArg==true), we add a 1791 // special check to see if the format string is a function parameter 1792 // of the function calling the printf function. If the function 1793 // has an attribute indicating it is a printf-like function, then we 1794 // should suppress warnings concerning non-literals being used in a call 1795 // to a vprintf function. For example: 1796 // 1797 // void 1798 // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){ 1799 // va_list ap; 1800 // va_start(ap, fmt); 1801 // vprintf(fmt, ap); // Do NOT emit a warning about "fmt". 1802 // ... 1803 // 1804 if (HasVAListArg) { 1805 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(VD)) { 1806 if (const NamedDecl *ND = dyn_cast<NamedDecl>(PV->getDeclContext())) { 1807 int PVIndex = PV->getFunctionScopeIndex() + 1; 1808 for (specific_attr_iterator<FormatAttr> 1809 i = ND->specific_attr_begin<FormatAttr>(), 1810 e = ND->specific_attr_end<FormatAttr>(); i != e ; ++i) { 1811 FormatAttr *PVFormat = *i; 1812 // adjust for implicit parameter 1813 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 1814 if (MD->isInstance()) 1815 ++PVIndex; 1816 // We also check if the formats are compatible. 1817 // We can't pass a 'scanf' string to a 'printf' function. 1818 if (PVIndex == PVFormat->getFormatIdx() && 1819 Type == GetFormatStringType(PVFormat)) 1820 return SLCT_UncheckedLiteral; 1821 } 1822 } 1823 } 1824 } 1825 } 1826 1827 return SLCT_NotALiteral; 1828 } 1829 1830 case Stmt::CallExprClass: 1831 case Stmt::CXXMemberCallExprClass: { 1832 const CallExpr *CE = cast<CallExpr>(E); 1833 if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) { 1834 if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) { 1835 unsigned ArgIndex = FA->getFormatIdx(); 1836 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 1837 if (MD->isInstance()) 1838 --ArgIndex; 1839 const Expr *Arg = CE->getArg(ArgIndex - 1); 1840 1841 return checkFormatStringExpr(Arg, Args, 1842 HasVAListArg, format_idx, firstDataArg, 1843 Type, CallType, inFunctionCall); 1844 } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) { 1845 unsigned BuiltinID = FD->getBuiltinID(); 1846 if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString || 1847 BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) { 1848 const Expr *Arg = CE->getArg(0); 1849 return checkFormatStringExpr(Arg, Args, 1850 HasVAListArg, format_idx, 1851 firstDataArg, Type, CallType, 1852 inFunctionCall); 1853 } 1854 } 1855 } 1856 1857 return SLCT_NotALiteral; 1858 } 1859 case Stmt::ObjCStringLiteralClass: 1860 case Stmt::StringLiteralClass: { 1861 const StringLiteral *StrE = NULL; 1862 1863 if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E)) 1864 StrE = ObjCFExpr->getString(); 1865 else 1866 StrE = cast<StringLiteral>(E); 1867 1868 if (StrE) { 1869 CheckFormatString(StrE, E, Args, HasVAListArg, format_idx, 1870 firstDataArg, Type, inFunctionCall, CallType); 1871 return SLCT_CheckedLiteral; 1872 } 1873 1874 return SLCT_NotALiteral; 1875 } 1876 1877 default: 1878 return SLCT_NotALiteral; 1879 } 1880} 1881 1882void 1883Sema::CheckNonNullArguments(const NonNullAttr *NonNull, 1884 const Expr * const *ExprArgs, 1885 SourceLocation CallSiteLoc) { 1886 for (NonNullAttr::args_iterator i = NonNull->args_begin(), 1887 e = NonNull->args_end(); 1888 i != e; ++i) { 1889 const Expr *ArgExpr = ExprArgs[*i]; 1890 1891 // As a special case, transparent unions initialized with zero are 1892 // considered null for the purposes of the nonnull attribute. 1893 if (const RecordType *UT = ArgExpr->getType()->getAsUnionType()) { 1894 if (UT->getDecl()->hasAttr<TransparentUnionAttr>()) 1895 if (const CompoundLiteralExpr *CLE = 1896 dyn_cast<CompoundLiteralExpr>(ArgExpr)) 1897 if (const InitListExpr *ILE = 1898 dyn_cast<InitListExpr>(CLE->getInitializer())) 1899 ArgExpr = ILE->getInit(0); 1900 } 1901 1902 bool Result; 1903 if (ArgExpr->EvaluateAsBooleanCondition(Result, Context) && !Result) 1904 Diag(CallSiteLoc, diag::warn_null_arg) << ArgExpr->getSourceRange(); 1905 } 1906} 1907 1908Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) { 1909 return llvm::StringSwitch<FormatStringType>(Format->getType()) 1910 .Case("scanf", FST_Scanf) 1911 .Cases("printf", "printf0", FST_Printf) 1912 .Cases("NSString", "CFString", FST_NSString) 1913 .Case("strftime", FST_Strftime) 1914 .Case("strfmon", FST_Strfmon) 1915 .Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf) 1916 .Default(FST_Unknown); 1917} 1918 1919/// CheckFormatArguments - Check calls to printf and scanf (and similar 1920/// functions) for correct use of format strings. 1921/// Returns true if a format string has been fully checked. 1922bool Sema::CheckFormatArguments(const FormatAttr *Format, 1923 ArrayRef<const Expr *> Args, 1924 bool IsCXXMember, 1925 VariadicCallType CallType, 1926 SourceLocation Loc, SourceRange Range) { 1927 FormatStringInfo FSI; 1928 if (getFormatStringInfo(Format, IsCXXMember, &FSI)) 1929 return CheckFormatArguments(Args, FSI.HasVAListArg, FSI.FormatIdx, 1930 FSI.FirstDataArg, GetFormatStringType(Format), 1931 CallType, Loc, Range); 1932 return false; 1933} 1934 1935bool Sema::CheckFormatArguments(ArrayRef<const Expr *> Args, 1936 bool HasVAListArg, unsigned format_idx, 1937 unsigned firstDataArg, FormatStringType Type, 1938 VariadicCallType CallType, 1939 SourceLocation Loc, SourceRange Range) { 1940 // CHECK: printf/scanf-like function is called with no format string. 1941 if (format_idx >= Args.size()) { 1942 Diag(Loc, diag::warn_missing_format_string) << Range; 1943 return false; 1944 } 1945 1946 const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts(); 1947 1948 // CHECK: format string is not a string literal. 1949 // 1950 // Dynamically generated format strings are difficult to 1951 // automatically vet at compile time. Requiring that format strings 1952 // are string literals: (1) permits the checking of format strings by 1953 // the compiler and thereby (2) can practically remove the source of 1954 // many format string exploits. 1955 1956 // Format string can be either ObjC string (e.g. @"%d") or 1957 // C string (e.g. "%d") 1958 // ObjC string uses the same format specifiers as C string, so we can use 1959 // the same format string checking logic for both ObjC and C strings. 1960 StringLiteralCheckType CT = 1961 checkFormatStringExpr(OrigFormatExpr, Args, HasVAListArg, 1962 format_idx, firstDataArg, Type, CallType); 1963 if (CT != SLCT_NotALiteral) 1964 // Literal format string found, check done! 1965 return CT == SLCT_CheckedLiteral; 1966 1967 // Strftime is particular as it always uses a single 'time' argument, 1968 // so it is safe to pass a non-literal string. 1969 if (Type == FST_Strftime) 1970 return false; 1971 1972 // Do not emit diag when the string param is a macro expansion and the 1973 // format is either NSString or CFString. This is a hack to prevent 1974 // diag when using the NSLocalizedString and CFCopyLocalizedString macros 1975 // which are usually used in place of NS and CF string literals. 1976 if (Type == FST_NSString && 1977 SourceMgr.isInSystemMacro(Args[format_idx]->getLocStart())) 1978 return false; 1979 1980 // If there are no arguments specified, warn with -Wformat-security, otherwise 1981 // warn only with -Wformat-nonliteral. 1982 if (Args.size() == firstDataArg) 1983 Diag(Args[format_idx]->getLocStart(), 1984 diag::warn_format_nonliteral_noargs) 1985 << OrigFormatExpr->getSourceRange(); 1986 else 1987 Diag(Args[format_idx]->getLocStart(), 1988 diag::warn_format_nonliteral) 1989 << OrigFormatExpr->getSourceRange(); 1990 return false; 1991} 1992 1993namespace { 1994class CheckFormatHandler : public analyze_format_string::FormatStringHandler { 1995protected: 1996 Sema &S; 1997 const StringLiteral *FExpr; 1998 const Expr *OrigFormatExpr; 1999 const unsigned FirstDataArg; 2000 const unsigned NumDataArgs; 2001 const char *Beg; // Start of format string. 2002 const bool HasVAListArg; 2003 ArrayRef<const Expr *> Args; 2004 unsigned FormatIdx; 2005 llvm::BitVector CoveredArgs; 2006 bool usesPositionalArgs; 2007 bool atFirstArg; 2008 bool inFunctionCall; 2009 Sema::VariadicCallType CallType; 2010public: 2011 CheckFormatHandler(Sema &s, const StringLiteral *fexpr, 2012 const Expr *origFormatExpr, unsigned firstDataArg, 2013 unsigned numDataArgs, const char *beg, bool hasVAListArg, 2014 ArrayRef<const Expr *> Args, 2015 unsigned formatIdx, bool inFunctionCall, 2016 Sema::VariadicCallType callType) 2017 : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr), 2018 FirstDataArg(firstDataArg), NumDataArgs(numDataArgs), 2019 Beg(beg), HasVAListArg(hasVAListArg), 2020 Args(Args), FormatIdx(formatIdx), 2021 usesPositionalArgs(false), atFirstArg(true), 2022 inFunctionCall(inFunctionCall), CallType(callType) { 2023 CoveredArgs.resize(numDataArgs); 2024 CoveredArgs.reset(); 2025 } 2026 2027 void DoneProcessing(); 2028 2029 void HandleIncompleteSpecifier(const char *startSpecifier, 2030 unsigned specifierLen); 2031 2032 void HandleInvalidLengthModifier( 2033 const analyze_format_string::FormatSpecifier &FS, 2034 const analyze_format_string::ConversionSpecifier &CS, 2035 const char *startSpecifier, unsigned specifierLen, unsigned DiagID); 2036 2037 void HandleNonStandardLengthModifier( 2038 const analyze_format_string::FormatSpecifier &FS, 2039 const char *startSpecifier, unsigned specifierLen); 2040 2041 void HandleNonStandardConversionSpecifier( 2042 const analyze_format_string::ConversionSpecifier &CS, 2043 const char *startSpecifier, unsigned specifierLen); 2044 2045 virtual void HandlePosition(const char *startPos, unsigned posLen); 2046 2047 virtual void HandleInvalidPosition(const char *startSpecifier, 2048 unsigned specifierLen, 2049 analyze_format_string::PositionContext p); 2050 2051 virtual void HandleZeroPosition(const char *startPos, unsigned posLen); 2052 2053 void HandleNullChar(const char *nullCharacter); 2054 2055 template <typename Range> 2056 static void EmitFormatDiagnostic(Sema &S, bool inFunctionCall, 2057 const Expr *ArgumentExpr, 2058 PartialDiagnostic PDiag, 2059 SourceLocation StringLoc, 2060 bool IsStringLocation, Range StringRange, 2061 ArrayRef<FixItHint> Fixit = None); 2062 2063protected: 2064 bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc, 2065 const char *startSpec, 2066 unsigned specifierLen, 2067 const char *csStart, unsigned csLen); 2068 2069 void HandlePositionalNonpositionalArgs(SourceLocation Loc, 2070 const char *startSpec, 2071 unsigned specifierLen); 2072 2073 SourceRange getFormatStringRange(); 2074 CharSourceRange getSpecifierRange(const char *startSpecifier, 2075 unsigned specifierLen); 2076 SourceLocation getLocationOfByte(const char *x); 2077 2078 const Expr *getDataArg(unsigned i) const; 2079 2080 bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS, 2081 const analyze_format_string::ConversionSpecifier &CS, 2082 const char *startSpecifier, unsigned specifierLen, 2083 unsigned argIndex); 2084 2085 template <typename Range> 2086 void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc, 2087 bool IsStringLocation, Range StringRange, 2088 ArrayRef<FixItHint> Fixit = None); 2089 2090 void CheckPositionalAndNonpositionalArgs( 2091 const analyze_format_string::FormatSpecifier *FS); 2092}; 2093} 2094 2095SourceRange CheckFormatHandler::getFormatStringRange() { 2096 return OrigFormatExpr->getSourceRange(); 2097} 2098 2099CharSourceRange CheckFormatHandler:: 2100getSpecifierRange(const char *startSpecifier, unsigned specifierLen) { 2101 SourceLocation Start = getLocationOfByte(startSpecifier); 2102 SourceLocation End = getLocationOfByte(startSpecifier + specifierLen - 1); 2103 2104 // Advance the end SourceLocation by one due to half-open ranges. 2105 End = End.getLocWithOffset(1); 2106 2107 return CharSourceRange::getCharRange(Start, End); 2108} 2109 2110SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) { 2111 return S.getLocationOfStringLiteralByte(FExpr, x - Beg); 2112} 2113 2114void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier, 2115 unsigned specifierLen){ 2116 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier), 2117 getLocationOfByte(startSpecifier), 2118 /*IsStringLocation*/true, 2119 getSpecifierRange(startSpecifier, specifierLen)); 2120} 2121 2122void CheckFormatHandler::HandleInvalidLengthModifier( 2123 const analyze_format_string::FormatSpecifier &FS, 2124 const analyze_format_string::ConversionSpecifier &CS, 2125 const char *startSpecifier, unsigned specifierLen, unsigned DiagID) { 2126 using namespace analyze_format_string; 2127 2128 const LengthModifier &LM = FS.getLengthModifier(); 2129 CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength()); 2130 2131 // See if we know how to fix this length modifier. 2132 Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier(); 2133 if (FixedLM) { 2134 EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(), 2135 getLocationOfByte(LM.getStart()), 2136 /*IsStringLocation*/true, 2137 getSpecifierRange(startSpecifier, specifierLen)); 2138 2139 S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier) 2140 << FixedLM->toString() 2141 << FixItHint::CreateReplacement(LMRange, FixedLM->toString()); 2142 2143 } else { 2144 FixItHint Hint; 2145 if (DiagID == diag::warn_format_nonsensical_length) 2146 Hint = FixItHint::CreateRemoval(LMRange); 2147 2148 EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(), 2149 getLocationOfByte(LM.getStart()), 2150 /*IsStringLocation*/true, 2151 getSpecifierRange(startSpecifier, specifierLen), 2152 Hint); 2153 } 2154} 2155 2156void CheckFormatHandler::HandleNonStandardLengthModifier( 2157 const analyze_format_string::FormatSpecifier &FS, 2158 const char *startSpecifier, unsigned specifierLen) { 2159 using namespace analyze_format_string; 2160 2161 const LengthModifier &LM = FS.getLengthModifier(); 2162 CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength()); 2163 2164 // See if we know how to fix this length modifier. 2165 Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier(); 2166 if (FixedLM) { 2167 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2168 << LM.toString() << 0, 2169 getLocationOfByte(LM.getStart()), 2170 /*IsStringLocation*/true, 2171 getSpecifierRange(startSpecifier, specifierLen)); 2172 2173 S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier) 2174 << FixedLM->toString() 2175 << FixItHint::CreateReplacement(LMRange, FixedLM->toString()); 2176 2177 } else { 2178 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2179 << LM.toString() << 0, 2180 getLocationOfByte(LM.getStart()), 2181 /*IsStringLocation*/true, 2182 getSpecifierRange(startSpecifier, specifierLen)); 2183 } 2184} 2185 2186void CheckFormatHandler::HandleNonStandardConversionSpecifier( 2187 const analyze_format_string::ConversionSpecifier &CS, 2188 const char *startSpecifier, unsigned specifierLen) { 2189 using namespace analyze_format_string; 2190 2191 // See if we know how to fix this conversion specifier. 2192 Optional<ConversionSpecifier> FixedCS = CS.getStandardSpecifier(); 2193 if (FixedCS) { 2194 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2195 << CS.toString() << /*conversion specifier*/1, 2196 getLocationOfByte(CS.getStart()), 2197 /*IsStringLocation*/true, 2198 getSpecifierRange(startSpecifier, specifierLen)); 2199 2200 CharSourceRange CSRange = getSpecifierRange(CS.getStart(), CS.getLength()); 2201 S.Diag(getLocationOfByte(CS.getStart()), diag::note_format_fix_specifier) 2202 << FixedCS->toString() 2203 << FixItHint::CreateReplacement(CSRange, FixedCS->toString()); 2204 } else { 2205 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2206 << CS.toString() << /*conversion specifier*/1, 2207 getLocationOfByte(CS.getStart()), 2208 /*IsStringLocation*/true, 2209 getSpecifierRange(startSpecifier, specifierLen)); 2210 } 2211} 2212 2213void CheckFormatHandler::HandlePosition(const char *startPos, 2214 unsigned posLen) { 2215 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg), 2216 getLocationOfByte(startPos), 2217 /*IsStringLocation*/true, 2218 getSpecifierRange(startPos, posLen)); 2219} 2220 2221void 2222CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen, 2223 analyze_format_string::PositionContext p) { 2224 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier) 2225 << (unsigned) p, 2226 getLocationOfByte(startPos), /*IsStringLocation*/true, 2227 getSpecifierRange(startPos, posLen)); 2228} 2229 2230void CheckFormatHandler::HandleZeroPosition(const char *startPos, 2231 unsigned posLen) { 2232 EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier), 2233 getLocationOfByte(startPos), 2234 /*IsStringLocation*/true, 2235 getSpecifierRange(startPos, posLen)); 2236} 2237 2238void CheckFormatHandler::HandleNullChar(const char *nullCharacter) { 2239 if (!isa<ObjCStringLiteral>(OrigFormatExpr)) { 2240 // The presence of a null character is likely an error. 2241 EmitFormatDiagnostic( 2242 S.PDiag(diag::warn_printf_format_string_contains_null_char), 2243 getLocationOfByte(nullCharacter), /*IsStringLocation*/true, 2244 getFormatStringRange()); 2245 } 2246} 2247 2248// Note that this may return NULL if there was an error parsing or building 2249// one of the argument expressions. 2250const Expr *CheckFormatHandler::getDataArg(unsigned i) const { 2251 return Args[FirstDataArg + i]; 2252} 2253 2254void CheckFormatHandler::DoneProcessing() { 2255 // Does the number of data arguments exceed the number of 2256 // format conversions in the format string? 2257 if (!HasVAListArg) { 2258 // Find any arguments that weren't covered. 2259 CoveredArgs.flip(); 2260 signed notCoveredArg = CoveredArgs.find_first(); 2261 if (notCoveredArg >= 0) { 2262 assert((unsigned)notCoveredArg < NumDataArgs); 2263 if (const Expr *E = getDataArg((unsigned) notCoveredArg)) { 2264 SourceLocation Loc = E->getLocStart(); 2265 if (!S.getSourceManager().isInSystemMacro(Loc)) { 2266 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_data_arg_not_used), 2267 Loc, /*IsStringLocation*/false, 2268 getFormatStringRange()); 2269 } 2270 } 2271 } 2272 } 2273} 2274 2275bool 2276CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex, 2277 SourceLocation Loc, 2278 const char *startSpec, 2279 unsigned specifierLen, 2280 const char *csStart, 2281 unsigned csLen) { 2282 2283 bool keepGoing = true; 2284 if (argIndex < NumDataArgs) { 2285 // Consider the argument coverered, even though the specifier doesn't 2286 // make sense. 2287 CoveredArgs.set(argIndex); 2288 } 2289 else { 2290 // If argIndex exceeds the number of data arguments we 2291 // don't issue a warning because that is just a cascade of warnings (and 2292 // they may have intended '%%' anyway). We don't want to continue processing 2293 // the format string after this point, however, as we will like just get 2294 // gibberish when trying to match arguments. 2295 keepGoing = false; 2296 } 2297 2298 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion) 2299 << StringRef(csStart, csLen), 2300 Loc, /*IsStringLocation*/true, 2301 getSpecifierRange(startSpec, specifierLen)); 2302 2303 return keepGoing; 2304} 2305 2306void 2307CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc, 2308 const char *startSpec, 2309 unsigned specifierLen) { 2310 EmitFormatDiagnostic( 2311 S.PDiag(diag::warn_format_mix_positional_nonpositional_args), 2312 Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen)); 2313} 2314 2315bool 2316CheckFormatHandler::CheckNumArgs( 2317 const analyze_format_string::FormatSpecifier &FS, 2318 const analyze_format_string::ConversionSpecifier &CS, 2319 const char *startSpecifier, unsigned specifierLen, unsigned argIndex) { 2320 2321 if (argIndex >= NumDataArgs) { 2322 PartialDiagnostic PDiag = FS.usesPositionalArg() 2323 ? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args) 2324 << (argIndex+1) << NumDataArgs) 2325 : S.PDiag(diag::warn_printf_insufficient_data_args); 2326 EmitFormatDiagnostic( 2327 PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true, 2328 getSpecifierRange(startSpecifier, specifierLen)); 2329 return false; 2330 } 2331 return true; 2332} 2333 2334template<typename Range> 2335void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag, 2336 SourceLocation Loc, 2337 bool IsStringLocation, 2338 Range StringRange, 2339 ArrayRef<FixItHint> FixIt) { 2340 EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag, 2341 Loc, IsStringLocation, StringRange, FixIt); 2342} 2343 2344/// \brief If the format string is not within the funcion call, emit a note 2345/// so that the function call and string are in diagnostic messages. 2346/// 2347/// \param InFunctionCall if true, the format string is within the function 2348/// call and only one diagnostic message will be produced. Otherwise, an 2349/// extra note will be emitted pointing to location of the format string. 2350/// 2351/// \param ArgumentExpr the expression that is passed as the format string 2352/// argument in the function call. Used for getting locations when two 2353/// diagnostics are emitted. 2354/// 2355/// \param PDiag the callee should already have provided any strings for the 2356/// diagnostic message. This function only adds locations and fixits 2357/// to diagnostics. 2358/// 2359/// \param Loc primary location for diagnostic. If two diagnostics are 2360/// required, one will be at Loc and a new SourceLocation will be created for 2361/// the other one. 2362/// 2363/// \param IsStringLocation if true, Loc points to the format string should be 2364/// used for the note. Otherwise, Loc points to the argument list and will 2365/// be used with PDiag. 2366/// 2367/// \param StringRange some or all of the string to highlight. This is 2368/// templated so it can accept either a CharSourceRange or a SourceRange. 2369/// 2370/// \param FixIt optional fix it hint for the format string. 2371template<typename Range> 2372void CheckFormatHandler::EmitFormatDiagnostic(Sema &S, bool InFunctionCall, 2373 const Expr *ArgumentExpr, 2374 PartialDiagnostic PDiag, 2375 SourceLocation Loc, 2376 bool IsStringLocation, 2377 Range StringRange, 2378 ArrayRef<FixItHint> FixIt) { 2379 if (InFunctionCall) { 2380 const Sema::SemaDiagnosticBuilder &D = S.Diag(Loc, PDiag); 2381 D << StringRange; 2382 for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end(); 2383 I != E; ++I) { 2384 D << *I; 2385 } 2386 } else { 2387 S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag) 2388 << ArgumentExpr->getSourceRange(); 2389 2390 const Sema::SemaDiagnosticBuilder &Note = 2391 S.Diag(IsStringLocation ? Loc : StringRange.getBegin(), 2392 diag::note_format_string_defined); 2393 2394 Note << StringRange; 2395 for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end(); 2396 I != E; ++I) { 2397 Note << *I; 2398 } 2399 } 2400} 2401 2402//===--- CHECK: Printf format string checking ------------------------------===// 2403 2404namespace { 2405class CheckPrintfHandler : public CheckFormatHandler { 2406 bool ObjCContext; 2407public: 2408 CheckPrintfHandler(Sema &s, const StringLiteral *fexpr, 2409 const Expr *origFormatExpr, unsigned firstDataArg, 2410 unsigned numDataArgs, bool isObjC, 2411 const char *beg, bool hasVAListArg, 2412 ArrayRef<const Expr *> Args, 2413 unsigned formatIdx, bool inFunctionCall, 2414 Sema::VariadicCallType CallType) 2415 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 2416 numDataArgs, beg, hasVAListArg, Args, 2417 formatIdx, inFunctionCall, CallType), ObjCContext(isObjC) 2418 {} 2419 2420 2421 bool HandleInvalidPrintfConversionSpecifier( 2422 const analyze_printf::PrintfSpecifier &FS, 2423 const char *startSpecifier, 2424 unsigned specifierLen); 2425 2426 bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS, 2427 const char *startSpecifier, 2428 unsigned specifierLen); 2429 bool checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 2430 const char *StartSpecifier, 2431 unsigned SpecifierLen, 2432 const Expr *E); 2433 2434 bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k, 2435 const char *startSpecifier, unsigned specifierLen); 2436 void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS, 2437 const analyze_printf::OptionalAmount &Amt, 2438 unsigned type, 2439 const char *startSpecifier, unsigned specifierLen); 2440 void HandleFlag(const analyze_printf::PrintfSpecifier &FS, 2441 const analyze_printf::OptionalFlag &flag, 2442 const char *startSpecifier, unsigned specifierLen); 2443 void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS, 2444 const analyze_printf::OptionalFlag &ignoredFlag, 2445 const analyze_printf::OptionalFlag &flag, 2446 const char *startSpecifier, unsigned specifierLen); 2447 bool checkForCStrMembers(const analyze_printf::ArgType &AT, 2448 const Expr *E, const CharSourceRange &CSR); 2449 2450}; 2451} 2452 2453bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier( 2454 const analyze_printf::PrintfSpecifier &FS, 2455 const char *startSpecifier, 2456 unsigned specifierLen) { 2457 const analyze_printf::PrintfConversionSpecifier &CS = 2458 FS.getConversionSpecifier(); 2459 2460 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 2461 getLocationOfByte(CS.getStart()), 2462 startSpecifier, specifierLen, 2463 CS.getStart(), CS.getLength()); 2464} 2465 2466bool CheckPrintfHandler::HandleAmount( 2467 const analyze_format_string::OptionalAmount &Amt, 2468 unsigned k, const char *startSpecifier, 2469 unsigned specifierLen) { 2470 2471 if (Amt.hasDataArgument()) { 2472 if (!HasVAListArg) { 2473 unsigned argIndex = Amt.getArgIndex(); 2474 if (argIndex >= NumDataArgs) { 2475 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg) 2476 << k, 2477 getLocationOfByte(Amt.getStart()), 2478 /*IsStringLocation*/true, 2479 getSpecifierRange(startSpecifier, specifierLen)); 2480 // Don't do any more checking. We will just emit 2481 // spurious errors. 2482 return false; 2483 } 2484 2485 // Type check the data argument. It should be an 'int'. 2486 // Although not in conformance with C99, we also allow the argument to be 2487 // an 'unsigned int' as that is a reasonably safe case. GCC also 2488 // doesn't emit a warning for that case. 2489 CoveredArgs.set(argIndex); 2490 const Expr *Arg = getDataArg(argIndex); 2491 if (!Arg) 2492 return false; 2493 2494 QualType T = Arg->getType(); 2495 2496 const analyze_printf::ArgType &AT = Amt.getArgType(S.Context); 2497 assert(AT.isValid()); 2498 2499 if (!AT.matchesType(S.Context, T)) { 2500 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type) 2501 << k << AT.getRepresentativeTypeName(S.Context) 2502 << T << Arg->getSourceRange(), 2503 getLocationOfByte(Amt.getStart()), 2504 /*IsStringLocation*/true, 2505 getSpecifierRange(startSpecifier, specifierLen)); 2506 // Don't do any more checking. We will just emit 2507 // spurious errors. 2508 return false; 2509 } 2510 } 2511 } 2512 return true; 2513} 2514 2515void CheckPrintfHandler::HandleInvalidAmount( 2516 const analyze_printf::PrintfSpecifier &FS, 2517 const analyze_printf::OptionalAmount &Amt, 2518 unsigned type, 2519 const char *startSpecifier, 2520 unsigned specifierLen) { 2521 const analyze_printf::PrintfConversionSpecifier &CS = 2522 FS.getConversionSpecifier(); 2523 2524 FixItHint fixit = 2525 Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant 2526 ? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(), 2527 Amt.getConstantLength())) 2528 : FixItHint(); 2529 2530 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount) 2531 << type << CS.toString(), 2532 getLocationOfByte(Amt.getStart()), 2533 /*IsStringLocation*/true, 2534 getSpecifierRange(startSpecifier, specifierLen), 2535 fixit); 2536} 2537 2538void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS, 2539 const analyze_printf::OptionalFlag &flag, 2540 const char *startSpecifier, 2541 unsigned specifierLen) { 2542 // Warn about pointless flag with a fixit removal. 2543 const analyze_printf::PrintfConversionSpecifier &CS = 2544 FS.getConversionSpecifier(); 2545 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag) 2546 << flag.toString() << CS.toString(), 2547 getLocationOfByte(flag.getPosition()), 2548 /*IsStringLocation*/true, 2549 getSpecifierRange(startSpecifier, specifierLen), 2550 FixItHint::CreateRemoval( 2551 getSpecifierRange(flag.getPosition(), 1))); 2552} 2553 2554void CheckPrintfHandler::HandleIgnoredFlag( 2555 const analyze_printf::PrintfSpecifier &FS, 2556 const analyze_printf::OptionalFlag &ignoredFlag, 2557 const analyze_printf::OptionalFlag &flag, 2558 const char *startSpecifier, 2559 unsigned specifierLen) { 2560 // Warn about ignored flag with a fixit removal. 2561 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag) 2562 << ignoredFlag.toString() << flag.toString(), 2563 getLocationOfByte(ignoredFlag.getPosition()), 2564 /*IsStringLocation*/true, 2565 getSpecifierRange(startSpecifier, specifierLen), 2566 FixItHint::CreateRemoval( 2567 getSpecifierRange(ignoredFlag.getPosition(), 1))); 2568} 2569 2570// Determines if the specified is a C++ class or struct containing 2571// a member with the specified name and kind (e.g. a CXXMethodDecl named 2572// "c_str()"). 2573template<typename MemberKind> 2574static llvm::SmallPtrSet<MemberKind*, 1> 2575CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) { 2576 const RecordType *RT = Ty->getAs<RecordType>(); 2577 llvm::SmallPtrSet<MemberKind*, 1> Results; 2578 2579 if (!RT) 2580 return Results; 2581 const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()); 2582 if (!RD) 2583 return Results; 2584 2585 LookupResult R(S, &S.PP.getIdentifierTable().get(Name), SourceLocation(), 2586 Sema::LookupMemberName); 2587 2588 // We just need to include all members of the right kind turned up by the 2589 // filter, at this point. 2590 if (S.LookupQualifiedName(R, RT->getDecl())) 2591 for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) { 2592 NamedDecl *decl = (*I)->getUnderlyingDecl(); 2593 if (MemberKind *FK = dyn_cast<MemberKind>(decl)) 2594 Results.insert(FK); 2595 } 2596 return Results; 2597} 2598 2599// Check if a (w)string was passed when a (w)char* was needed, and offer a 2600// better diagnostic if so. AT is assumed to be valid. 2601// Returns true when a c_str() conversion method is found. 2602bool CheckPrintfHandler::checkForCStrMembers( 2603 const analyze_printf::ArgType &AT, const Expr *E, 2604 const CharSourceRange &CSR) { 2605 typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet; 2606 2607 MethodSet Results = 2608 CXXRecordMembersNamed<CXXMethodDecl>("c_str", S, E->getType()); 2609 2610 for (MethodSet::iterator MI = Results.begin(), ME = Results.end(); 2611 MI != ME; ++MI) { 2612 const CXXMethodDecl *Method = *MI; 2613 if (Method->getNumParams() == 0 && 2614 AT.matchesType(S.Context, Method->getResultType())) { 2615 // FIXME: Suggest parens if the expression needs them. 2616 SourceLocation EndLoc = 2617 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()); 2618 S.Diag(E->getLocStart(), diag::note_printf_c_str) 2619 << "c_str()" 2620 << FixItHint::CreateInsertion(EndLoc, ".c_str()"); 2621 return true; 2622 } 2623 } 2624 2625 return false; 2626} 2627 2628bool 2629CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier 2630 &FS, 2631 const char *startSpecifier, 2632 unsigned specifierLen) { 2633 2634 using namespace analyze_format_string; 2635 using namespace analyze_printf; 2636 const PrintfConversionSpecifier &CS = FS.getConversionSpecifier(); 2637 2638 if (FS.consumesDataArgument()) { 2639 if (atFirstArg) { 2640 atFirstArg = false; 2641 usesPositionalArgs = FS.usesPositionalArg(); 2642 } 2643 else if (usesPositionalArgs != FS.usesPositionalArg()) { 2644 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 2645 startSpecifier, specifierLen); 2646 return false; 2647 } 2648 } 2649 2650 // First check if the field width, precision, and conversion specifier 2651 // have matching data arguments. 2652 if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0, 2653 startSpecifier, specifierLen)) { 2654 return false; 2655 } 2656 2657 if (!HandleAmount(FS.getPrecision(), /* precision */ 1, 2658 startSpecifier, specifierLen)) { 2659 return false; 2660 } 2661 2662 if (!CS.consumesDataArgument()) { 2663 // FIXME: Technically specifying a precision or field width here 2664 // makes no sense. Worth issuing a warning at some point. 2665 return true; 2666 } 2667 2668 // Consume the argument. 2669 unsigned argIndex = FS.getArgIndex(); 2670 if (argIndex < NumDataArgs) { 2671 // The check to see if the argIndex is valid will come later. 2672 // We set the bit here because we may exit early from this 2673 // function if we encounter some other error. 2674 CoveredArgs.set(argIndex); 2675 } 2676 2677 // Check for using an Objective-C specific conversion specifier 2678 // in a non-ObjC literal. 2679 if (!ObjCContext && CS.isObjCArg()) { 2680 return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier, 2681 specifierLen); 2682 } 2683 2684 // Check for invalid use of field width 2685 if (!FS.hasValidFieldWidth()) { 2686 HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0, 2687 startSpecifier, specifierLen); 2688 } 2689 2690 // Check for invalid use of precision 2691 if (!FS.hasValidPrecision()) { 2692 HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1, 2693 startSpecifier, specifierLen); 2694 } 2695 2696 // Check each flag does not conflict with any other component. 2697 if (!FS.hasValidThousandsGroupingPrefix()) 2698 HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen); 2699 if (!FS.hasValidLeadingZeros()) 2700 HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen); 2701 if (!FS.hasValidPlusPrefix()) 2702 HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen); 2703 if (!FS.hasValidSpacePrefix()) 2704 HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen); 2705 if (!FS.hasValidAlternativeForm()) 2706 HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen); 2707 if (!FS.hasValidLeftJustified()) 2708 HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen); 2709 2710 // Check that flags are not ignored by another flag 2711 if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+' 2712 HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(), 2713 startSpecifier, specifierLen); 2714 if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-' 2715 HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(), 2716 startSpecifier, specifierLen); 2717 2718 // Check the length modifier is valid with the given conversion specifier. 2719 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 2720 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 2721 diag::warn_format_nonsensical_length); 2722 else if (!FS.hasStandardLengthModifier()) 2723 HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen); 2724 else if (!FS.hasStandardLengthConversionCombination()) 2725 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 2726 diag::warn_format_non_standard_conversion_spec); 2727 2728 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 2729 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 2730 2731 // The remaining checks depend on the data arguments. 2732 if (HasVAListArg) 2733 return true; 2734 2735 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 2736 return false; 2737 2738 const Expr *Arg = getDataArg(argIndex); 2739 if (!Arg) 2740 return true; 2741 2742 return checkFormatExpr(FS, startSpecifier, specifierLen, Arg); 2743} 2744 2745static bool requiresParensToAddCast(const Expr *E) { 2746 // FIXME: We should have a general way to reason about operator 2747 // precedence and whether parens are actually needed here. 2748 // Take care of a few common cases where they aren't. 2749 const Expr *Inside = E->IgnoreImpCasts(); 2750 if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Inside)) 2751 Inside = POE->getSyntacticForm()->IgnoreImpCasts(); 2752 2753 switch (Inside->getStmtClass()) { 2754 case Stmt::ArraySubscriptExprClass: 2755 case Stmt::CallExprClass: 2756 case Stmt::CharacterLiteralClass: 2757 case Stmt::CXXBoolLiteralExprClass: 2758 case Stmt::DeclRefExprClass: 2759 case Stmt::FloatingLiteralClass: 2760 case Stmt::IntegerLiteralClass: 2761 case Stmt::MemberExprClass: 2762 case Stmt::ObjCArrayLiteralClass: 2763 case Stmt::ObjCBoolLiteralExprClass: 2764 case Stmt::ObjCBoxedExprClass: 2765 case Stmt::ObjCDictionaryLiteralClass: 2766 case Stmt::ObjCEncodeExprClass: 2767 case Stmt::ObjCIvarRefExprClass: 2768 case Stmt::ObjCMessageExprClass: 2769 case Stmt::ObjCPropertyRefExprClass: 2770 case Stmt::ObjCStringLiteralClass: 2771 case Stmt::ObjCSubscriptRefExprClass: 2772 case Stmt::ParenExprClass: 2773 case Stmt::StringLiteralClass: 2774 case Stmt::UnaryOperatorClass: 2775 return false; 2776 default: 2777 return true; 2778 } 2779} 2780 2781bool 2782CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 2783 const char *StartSpecifier, 2784 unsigned SpecifierLen, 2785 const Expr *E) { 2786 using namespace analyze_format_string; 2787 using namespace analyze_printf; 2788 // Now type check the data expression that matches the 2789 // format specifier. 2790 const analyze_printf::ArgType &AT = FS.getArgType(S.Context, 2791 ObjCContext); 2792 if (!AT.isValid()) 2793 return true; 2794 2795 QualType ExprTy = E->getType(); 2796 while (const TypeOfExprType *TET = dyn_cast<TypeOfExprType>(ExprTy)) { 2797 ExprTy = TET->getUnderlyingExpr()->getType(); 2798 } 2799 2800 if (AT.matchesType(S.Context, ExprTy)) 2801 return true; 2802 2803 // Look through argument promotions for our error message's reported type. 2804 // This includes the integral and floating promotions, but excludes array 2805 // and function pointer decay; seeing that an argument intended to be a 2806 // string has type 'char [6]' is probably more confusing than 'char *'. 2807 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 2808 if (ICE->getCastKind() == CK_IntegralCast || 2809 ICE->getCastKind() == CK_FloatingCast) { 2810 E = ICE->getSubExpr(); 2811 ExprTy = E->getType(); 2812 2813 // Check if we didn't match because of an implicit cast from a 'char' 2814 // or 'short' to an 'int'. This is done because printf is a varargs 2815 // function. 2816 if (ICE->getType() == S.Context.IntTy || 2817 ICE->getType() == S.Context.UnsignedIntTy) { 2818 // All further checking is done on the subexpression. 2819 if (AT.matchesType(S.Context, ExprTy)) 2820 return true; 2821 } 2822 } 2823 } else if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E)) { 2824 // Special case for 'a', which has type 'int' in C. 2825 // Note, however, that we do /not/ want to treat multibyte constants like 2826 // 'MooV' as characters! This form is deprecated but still exists. 2827 if (ExprTy == S.Context.IntTy) 2828 if (llvm::isUIntN(S.Context.getCharWidth(), CL->getValue())) 2829 ExprTy = S.Context.CharTy; 2830 } 2831 2832 // %C in an Objective-C context prints a unichar, not a wchar_t. 2833 // If the argument is an integer of some kind, believe the %C and suggest 2834 // a cast instead of changing the conversion specifier. 2835 QualType IntendedTy = ExprTy; 2836 if (ObjCContext && 2837 FS.getConversionSpecifier().getKind() == ConversionSpecifier::CArg) { 2838 if (ExprTy->isIntegralOrUnscopedEnumerationType() && 2839 !ExprTy->isCharType()) { 2840 // 'unichar' is defined as a typedef of unsigned short, but we should 2841 // prefer using the typedef if it is visible. 2842 IntendedTy = S.Context.UnsignedShortTy; 2843 2844 LookupResult Result(S, &S.Context.Idents.get("unichar"), E->getLocStart(), 2845 Sema::LookupOrdinaryName); 2846 if (S.LookupName(Result, S.getCurScope())) { 2847 NamedDecl *ND = Result.getFoundDecl(); 2848 if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(ND)) 2849 if (TD->getUnderlyingType() == IntendedTy) 2850 IntendedTy = S.Context.getTypedefType(TD); 2851 } 2852 } 2853 } 2854 2855 // Special-case some of Darwin's platform-independence types by suggesting 2856 // casts to primitive types that are known to be large enough. 2857 bool ShouldNotPrintDirectly = false; 2858 if (S.Context.getTargetInfo().getTriple().isOSDarwin()) { 2859 // Use a 'while' to peel off layers of typedefs. 2860 QualType TyTy = IntendedTy; 2861 while (const TypedefType *UserTy = TyTy->getAs<TypedefType>()) { 2862 StringRef Name = UserTy->getDecl()->getName(); 2863 QualType CastTy = llvm::StringSwitch<QualType>(Name) 2864 .Case("NSInteger", S.Context.LongTy) 2865 .Case("NSUInteger", S.Context.UnsignedLongTy) 2866 .Case("SInt32", S.Context.IntTy) 2867 .Case("UInt32", S.Context.UnsignedIntTy) 2868 .Default(QualType()); 2869 2870 if (!CastTy.isNull()) { 2871 ShouldNotPrintDirectly = true; 2872 IntendedTy = CastTy; 2873 break; 2874 } 2875 TyTy = UserTy->desugar(); 2876 } 2877 } 2878 2879 // We may be able to offer a FixItHint if it is a supported type. 2880 PrintfSpecifier fixedFS = FS; 2881 bool success = fixedFS.fixType(IntendedTy, S.getLangOpts(), 2882 S.Context, ObjCContext); 2883 2884 if (success) { 2885 // Get the fix string from the fixed format specifier 2886 SmallString<16> buf; 2887 llvm::raw_svector_ostream os(buf); 2888 fixedFS.toString(os); 2889 2890 CharSourceRange SpecRange = getSpecifierRange(StartSpecifier, SpecifierLen); 2891 2892 if (IntendedTy == ExprTy) { 2893 // In this case, the specifier is wrong and should be changed to match 2894 // the argument. 2895 EmitFormatDiagnostic( 2896 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2897 << AT.getRepresentativeTypeName(S.Context) << IntendedTy 2898 << E->getSourceRange(), 2899 E->getLocStart(), 2900 /*IsStringLocation*/false, 2901 SpecRange, 2902 FixItHint::CreateReplacement(SpecRange, os.str())); 2903 2904 } else { 2905 // The canonical type for formatting this value is different from the 2906 // actual type of the expression. (This occurs, for example, with Darwin's 2907 // NSInteger on 32-bit platforms, where it is typedef'd as 'int', but 2908 // should be printed as 'long' for 64-bit compatibility.) 2909 // Rather than emitting a normal format/argument mismatch, we want to 2910 // add a cast to the recommended type (and correct the format string 2911 // if necessary). 2912 SmallString<16> CastBuf; 2913 llvm::raw_svector_ostream CastFix(CastBuf); 2914 CastFix << "("; 2915 IntendedTy.print(CastFix, S.Context.getPrintingPolicy()); 2916 CastFix << ")"; 2917 2918 SmallVector<FixItHint,4> Hints; 2919 if (!AT.matchesType(S.Context, IntendedTy)) 2920 Hints.push_back(FixItHint::CreateReplacement(SpecRange, os.str())); 2921 2922 if (const CStyleCastExpr *CCast = dyn_cast<CStyleCastExpr>(E)) { 2923 // If there's already a cast present, just replace it. 2924 SourceRange CastRange(CCast->getLParenLoc(), CCast->getRParenLoc()); 2925 Hints.push_back(FixItHint::CreateReplacement(CastRange, CastFix.str())); 2926 2927 } else if (!requiresParensToAddCast(E)) { 2928 // If the expression has high enough precedence, 2929 // just write the C-style cast. 2930 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 2931 CastFix.str())); 2932 } else { 2933 // Otherwise, add parens around the expression as well as the cast. 2934 CastFix << "("; 2935 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 2936 CastFix.str())); 2937 2938 SourceLocation After = S.PP.getLocForEndOfToken(E->getLocEnd()); 2939 Hints.push_back(FixItHint::CreateInsertion(After, ")")); 2940 } 2941 2942 if (ShouldNotPrintDirectly) { 2943 // The expression has a type that should not be printed directly. 2944 // We extract the name from the typedef because we don't want to show 2945 // the underlying type in the diagnostic. 2946 StringRef Name = cast<TypedefType>(ExprTy)->getDecl()->getName(); 2947 2948 EmitFormatDiagnostic(S.PDiag(diag::warn_format_argument_needs_cast) 2949 << Name << IntendedTy 2950 << E->getSourceRange(), 2951 E->getLocStart(), /*IsStringLocation=*/false, 2952 SpecRange, Hints); 2953 } else { 2954 // In this case, the expression could be printed using a different 2955 // specifier, but we've decided that the specifier is probably correct 2956 // and we should cast instead. Just use the normal warning message. 2957 EmitFormatDiagnostic( 2958 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2959 << AT.getRepresentativeTypeName(S.Context) << ExprTy 2960 << E->getSourceRange(), 2961 E->getLocStart(), /*IsStringLocation*/false, 2962 SpecRange, Hints); 2963 } 2964 } 2965 } else { 2966 const CharSourceRange &CSR = getSpecifierRange(StartSpecifier, 2967 SpecifierLen); 2968 // Since the warning for passing non-POD types to variadic functions 2969 // was deferred until now, we emit a warning for non-POD 2970 // arguments here. 2971 if (S.isValidVarArgType(ExprTy) == Sema::VAK_Invalid) { 2972 unsigned DiagKind; 2973 if (ExprTy->isObjCObjectType()) 2974 DiagKind = diag::err_cannot_pass_objc_interface_to_vararg_format; 2975 else 2976 DiagKind = diag::warn_non_pod_vararg_with_format_string; 2977 2978 EmitFormatDiagnostic( 2979 S.PDiag(DiagKind) 2980 << S.getLangOpts().CPlusPlus11 2981 << ExprTy 2982 << CallType 2983 << AT.getRepresentativeTypeName(S.Context) 2984 << CSR 2985 << E->getSourceRange(), 2986 E->getLocStart(), /*IsStringLocation*/false, CSR); 2987 2988 checkForCStrMembers(AT, E, CSR); 2989 } else 2990 EmitFormatDiagnostic( 2991 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2992 << AT.getRepresentativeTypeName(S.Context) << ExprTy 2993 << CSR 2994 << E->getSourceRange(), 2995 E->getLocStart(), /*IsStringLocation*/false, CSR); 2996 } 2997 2998 return true; 2999} 3000 3001//===--- CHECK: Scanf format string checking ------------------------------===// 3002 3003namespace { 3004class CheckScanfHandler : public CheckFormatHandler { 3005public: 3006 CheckScanfHandler(Sema &s, const StringLiteral *fexpr, 3007 const Expr *origFormatExpr, unsigned firstDataArg, 3008 unsigned numDataArgs, const char *beg, bool hasVAListArg, 3009 ArrayRef<const Expr *> Args, 3010 unsigned formatIdx, bool inFunctionCall, 3011 Sema::VariadicCallType CallType) 3012 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 3013 numDataArgs, beg, hasVAListArg, 3014 Args, formatIdx, inFunctionCall, CallType) 3015 {} 3016 3017 bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS, 3018 const char *startSpecifier, 3019 unsigned specifierLen); 3020 3021 bool HandleInvalidScanfConversionSpecifier( 3022 const analyze_scanf::ScanfSpecifier &FS, 3023 const char *startSpecifier, 3024 unsigned specifierLen); 3025 3026 void HandleIncompleteScanList(const char *start, const char *end); 3027}; 3028} 3029 3030void CheckScanfHandler::HandleIncompleteScanList(const char *start, 3031 const char *end) { 3032 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete), 3033 getLocationOfByte(end), /*IsStringLocation*/true, 3034 getSpecifierRange(start, end - start)); 3035} 3036 3037bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier( 3038 const analyze_scanf::ScanfSpecifier &FS, 3039 const char *startSpecifier, 3040 unsigned specifierLen) { 3041 3042 const analyze_scanf::ScanfConversionSpecifier &CS = 3043 FS.getConversionSpecifier(); 3044 3045 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 3046 getLocationOfByte(CS.getStart()), 3047 startSpecifier, specifierLen, 3048 CS.getStart(), CS.getLength()); 3049} 3050 3051bool CheckScanfHandler::HandleScanfSpecifier( 3052 const analyze_scanf::ScanfSpecifier &FS, 3053 const char *startSpecifier, 3054 unsigned specifierLen) { 3055 3056 using namespace analyze_scanf; 3057 using namespace analyze_format_string; 3058 3059 const ScanfConversionSpecifier &CS = FS.getConversionSpecifier(); 3060 3061 // Handle case where '%' and '*' don't consume an argument. These shouldn't 3062 // be used to decide if we are using positional arguments consistently. 3063 if (FS.consumesDataArgument()) { 3064 if (atFirstArg) { 3065 atFirstArg = false; 3066 usesPositionalArgs = FS.usesPositionalArg(); 3067 } 3068 else if (usesPositionalArgs != FS.usesPositionalArg()) { 3069 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 3070 startSpecifier, specifierLen); 3071 return false; 3072 } 3073 } 3074 3075 // Check if the field with is non-zero. 3076 const OptionalAmount &Amt = FS.getFieldWidth(); 3077 if (Amt.getHowSpecified() == OptionalAmount::Constant) { 3078 if (Amt.getConstantAmount() == 0) { 3079 const CharSourceRange &R = getSpecifierRange(Amt.getStart(), 3080 Amt.getConstantLength()); 3081 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width), 3082 getLocationOfByte(Amt.getStart()), 3083 /*IsStringLocation*/true, R, 3084 FixItHint::CreateRemoval(R)); 3085 } 3086 } 3087 3088 if (!FS.consumesDataArgument()) { 3089 // FIXME: Technically specifying a precision or field width here 3090 // makes no sense. Worth issuing a warning at some point. 3091 return true; 3092 } 3093 3094 // Consume the argument. 3095 unsigned argIndex = FS.getArgIndex(); 3096 if (argIndex < NumDataArgs) { 3097 // The check to see if the argIndex is valid will come later. 3098 // We set the bit here because we may exit early from this 3099 // function if we encounter some other error. 3100 CoveredArgs.set(argIndex); 3101 } 3102 3103 // Check the length modifier is valid with the given conversion specifier. 3104 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 3105 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 3106 diag::warn_format_nonsensical_length); 3107 else if (!FS.hasStandardLengthModifier()) 3108 HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen); 3109 else if (!FS.hasStandardLengthConversionCombination()) 3110 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 3111 diag::warn_format_non_standard_conversion_spec); 3112 3113 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 3114 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 3115 3116 // The remaining checks depend on the data arguments. 3117 if (HasVAListArg) 3118 return true; 3119 3120 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 3121 return false; 3122 3123 // Check that the argument type matches the format specifier. 3124 const Expr *Ex = getDataArg(argIndex); 3125 if (!Ex) 3126 return true; 3127 3128 const analyze_format_string::ArgType &AT = FS.getArgType(S.Context); 3129 if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType())) { 3130 ScanfSpecifier fixedFS = FS; 3131 bool success = fixedFS.fixType(Ex->getType(), S.getLangOpts(), 3132 S.Context); 3133 3134 if (success) { 3135 // Get the fix string from the fixed format specifier. 3136 SmallString<128> buf; 3137 llvm::raw_svector_ostream os(buf); 3138 fixedFS.toString(os); 3139 3140 EmitFormatDiagnostic( 3141 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 3142 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() 3143 << Ex->getSourceRange(), 3144 Ex->getLocStart(), 3145 /*IsStringLocation*/false, 3146 getSpecifierRange(startSpecifier, specifierLen), 3147 FixItHint::CreateReplacement( 3148 getSpecifierRange(startSpecifier, specifierLen), 3149 os.str())); 3150 } else { 3151 EmitFormatDiagnostic( 3152 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 3153 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() 3154 << Ex->getSourceRange(), 3155 Ex->getLocStart(), 3156 /*IsStringLocation*/false, 3157 getSpecifierRange(startSpecifier, specifierLen)); 3158 } 3159 } 3160 3161 return true; 3162} 3163 3164void Sema::CheckFormatString(const StringLiteral *FExpr, 3165 const Expr *OrigFormatExpr, 3166 ArrayRef<const Expr *> Args, 3167 bool HasVAListArg, unsigned format_idx, 3168 unsigned firstDataArg, FormatStringType Type, 3169 bool inFunctionCall, VariadicCallType CallType) { 3170 3171 // CHECK: is the format string a wide literal? 3172 if (!FExpr->isAscii() && !FExpr->isUTF8()) { 3173 CheckFormatHandler::EmitFormatDiagnostic( 3174 *this, inFunctionCall, Args[format_idx], 3175 PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(), 3176 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 3177 return; 3178 } 3179 3180 // Str - The format string. NOTE: this is NOT null-terminated! 3181 StringRef StrRef = FExpr->getString(); 3182 const char *Str = StrRef.data(); 3183 unsigned StrLen = StrRef.size(); 3184 const unsigned numDataArgs = Args.size() - firstDataArg; 3185 3186 // CHECK: empty format string? 3187 if (StrLen == 0 && numDataArgs > 0) { 3188 CheckFormatHandler::EmitFormatDiagnostic( 3189 *this, inFunctionCall, Args[format_idx], 3190 PDiag(diag::warn_empty_format_string), FExpr->getLocStart(), 3191 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 3192 return; 3193 } 3194 3195 if (Type == FST_Printf || Type == FST_NSString) { 3196 CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 3197 numDataArgs, (Type == FST_NSString), 3198 Str, HasVAListArg, Args, format_idx, 3199 inFunctionCall, CallType); 3200 3201 if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen, 3202 getLangOpts(), 3203 Context.getTargetInfo())) 3204 H.DoneProcessing(); 3205 } else if (Type == FST_Scanf) { 3206 CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, numDataArgs, 3207 Str, HasVAListArg, Args, format_idx, 3208 inFunctionCall, CallType); 3209 3210 if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen, 3211 getLangOpts(), 3212 Context.getTargetInfo())) 3213 H.DoneProcessing(); 3214 } // TODO: handle other formats 3215} 3216 3217//===--- CHECK: Standard memory functions ---------------------------------===// 3218 3219/// \brief Determine whether the given type is a dynamic class type (e.g., 3220/// whether it has a vtable). 3221static bool isDynamicClassType(QualType T) { 3222 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) 3223 if (CXXRecordDecl *Definition = Record->getDefinition()) 3224 if (Definition->isDynamicClass()) 3225 return true; 3226 3227 return false; 3228} 3229 3230/// \brief If E is a sizeof expression, returns its argument expression, 3231/// otherwise returns NULL. 3232static const Expr *getSizeOfExprArg(const Expr* E) { 3233 if (const UnaryExprOrTypeTraitExpr *SizeOf = 3234 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 3235 if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType()) 3236 return SizeOf->getArgumentExpr()->IgnoreParenImpCasts(); 3237 3238 return 0; 3239} 3240 3241/// \brief If E is a sizeof expression, returns its argument type. 3242static QualType getSizeOfArgType(const Expr* E) { 3243 if (const UnaryExprOrTypeTraitExpr *SizeOf = 3244 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 3245 if (SizeOf->getKind() == clang::UETT_SizeOf) 3246 return SizeOf->getTypeOfArgument(); 3247 3248 return QualType(); 3249} 3250 3251/// \brief Check for dangerous or invalid arguments to memset(). 3252/// 3253/// This issues warnings on known problematic, dangerous or unspecified 3254/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp' 3255/// function calls. 3256/// 3257/// \param Call The call expression to diagnose. 3258void Sema::CheckMemaccessArguments(const CallExpr *Call, 3259 unsigned BId, 3260 IdentifierInfo *FnName) { 3261 assert(BId != 0); 3262 3263 // It is possible to have a non-standard definition of memset. Validate 3264 // we have enough arguments, and if not, abort further checking. 3265 unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3); 3266 if (Call->getNumArgs() < ExpectedNumArgs) 3267 return; 3268 3269 unsigned LastArg = (BId == Builtin::BImemset || 3270 BId == Builtin::BIstrndup ? 1 : 2); 3271 unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2); 3272 const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts(); 3273 3274 // We have special checking when the length is a sizeof expression. 3275 QualType SizeOfArgTy = getSizeOfArgType(LenExpr); 3276 const Expr *SizeOfArg = getSizeOfExprArg(LenExpr); 3277 llvm::FoldingSetNodeID SizeOfArgID; 3278 3279 for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) { 3280 const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts(); 3281 SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange(); 3282 3283 QualType DestTy = Dest->getType(); 3284 if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) { 3285 QualType PointeeTy = DestPtrTy->getPointeeType(); 3286 3287 // Never warn about void type pointers. This can be used to suppress 3288 // false positives. 3289 if (PointeeTy->isVoidType()) 3290 continue; 3291 3292 // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by 3293 // actually comparing the expressions for equality. Because computing the 3294 // expression IDs can be expensive, we only do this if the diagnostic is 3295 // enabled. 3296 if (SizeOfArg && 3297 Diags.getDiagnosticLevel(diag::warn_sizeof_pointer_expr_memaccess, 3298 SizeOfArg->getExprLoc())) { 3299 // We only compute IDs for expressions if the warning is enabled, and 3300 // cache the sizeof arg's ID. 3301 if (SizeOfArgID == llvm::FoldingSetNodeID()) 3302 SizeOfArg->Profile(SizeOfArgID, Context, true); 3303 llvm::FoldingSetNodeID DestID; 3304 Dest->Profile(DestID, Context, true); 3305 if (DestID == SizeOfArgID) { 3306 // TODO: For strncpy() and friends, this could suggest sizeof(dst) 3307 // over sizeof(src) as well. 3308 unsigned ActionIdx = 0; // Default is to suggest dereferencing. 3309 StringRef ReadableName = FnName->getName(); 3310 3311 if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest)) 3312 if (UnaryOp->getOpcode() == UO_AddrOf) 3313 ActionIdx = 1; // If its an address-of operator, just remove it. 3314 if (!PointeeTy->isIncompleteType() && 3315 (Context.getTypeSize(PointeeTy) == Context.getCharWidth())) 3316 ActionIdx = 2; // If the pointee's size is sizeof(char), 3317 // suggest an explicit length. 3318 3319 // If the function is defined as a builtin macro, do not show macro 3320 // expansion. 3321 SourceLocation SL = SizeOfArg->getExprLoc(); 3322 SourceRange DSR = Dest->getSourceRange(); 3323 SourceRange SSR = SizeOfArg->getSourceRange(); 3324 SourceManager &SM = PP.getSourceManager(); 3325 3326 if (SM.isMacroArgExpansion(SL)) { 3327 ReadableName = Lexer::getImmediateMacroName(SL, SM, LangOpts); 3328 SL = SM.getSpellingLoc(SL); 3329 DSR = SourceRange(SM.getSpellingLoc(DSR.getBegin()), 3330 SM.getSpellingLoc(DSR.getEnd())); 3331 SSR = SourceRange(SM.getSpellingLoc(SSR.getBegin()), 3332 SM.getSpellingLoc(SSR.getEnd())); 3333 } 3334 3335 DiagRuntimeBehavior(SL, SizeOfArg, 3336 PDiag(diag::warn_sizeof_pointer_expr_memaccess) 3337 << ReadableName 3338 << PointeeTy 3339 << DestTy 3340 << DSR 3341 << SSR); 3342 DiagRuntimeBehavior(SL, SizeOfArg, 3343 PDiag(diag::warn_sizeof_pointer_expr_memaccess_note) 3344 << ActionIdx 3345 << SSR); 3346 3347 break; 3348 } 3349 } 3350 3351 // Also check for cases where the sizeof argument is the exact same 3352 // type as the memory argument, and where it points to a user-defined 3353 // record type. 3354 if (SizeOfArgTy != QualType()) { 3355 if (PointeeTy->isRecordType() && 3356 Context.typesAreCompatible(SizeOfArgTy, DestTy)) { 3357 DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest, 3358 PDiag(diag::warn_sizeof_pointer_type_memaccess) 3359 << FnName << SizeOfArgTy << ArgIdx 3360 << PointeeTy << Dest->getSourceRange() 3361 << LenExpr->getSourceRange()); 3362 break; 3363 } 3364 } 3365 3366 // Always complain about dynamic classes. 3367 if (isDynamicClassType(PointeeTy)) { 3368 3369 unsigned OperationType = 0; 3370 // "overwritten" if we're warning about the destination for any call 3371 // but memcmp; otherwise a verb appropriate to the call. 3372 if (ArgIdx != 0 || BId == Builtin::BImemcmp) { 3373 if (BId == Builtin::BImemcpy) 3374 OperationType = 1; 3375 else if(BId == Builtin::BImemmove) 3376 OperationType = 2; 3377 else if (BId == Builtin::BImemcmp) 3378 OperationType = 3; 3379 } 3380 3381 DiagRuntimeBehavior( 3382 Dest->getExprLoc(), Dest, 3383 PDiag(diag::warn_dyn_class_memaccess) 3384 << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx) 3385 << FnName << PointeeTy 3386 << OperationType 3387 << Call->getCallee()->getSourceRange()); 3388 } else if (PointeeTy.hasNonTrivialObjCLifetime() && 3389 BId != Builtin::BImemset) 3390 DiagRuntimeBehavior( 3391 Dest->getExprLoc(), Dest, 3392 PDiag(diag::warn_arc_object_memaccess) 3393 << ArgIdx << FnName << PointeeTy 3394 << Call->getCallee()->getSourceRange()); 3395 else 3396 continue; 3397 3398 DiagRuntimeBehavior( 3399 Dest->getExprLoc(), Dest, 3400 PDiag(diag::note_bad_memaccess_silence) 3401 << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)")); 3402 break; 3403 } 3404 } 3405} 3406 3407// A little helper routine: ignore addition and subtraction of integer literals. 3408// This intentionally does not ignore all integer constant expressions because 3409// we don't want to remove sizeof(). 3410static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) { 3411 Ex = Ex->IgnoreParenCasts(); 3412 3413 for (;;) { 3414 const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex); 3415 if (!BO || !BO->isAdditiveOp()) 3416 break; 3417 3418 const Expr *RHS = BO->getRHS()->IgnoreParenCasts(); 3419 const Expr *LHS = BO->getLHS()->IgnoreParenCasts(); 3420 3421 if (isa<IntegerLiteral>(RHS)) 3422 Ex = LHS; 3423 else if (isa<IntegerLiteral>(LHS)) 3424 Ex = RHS; 3425 else 3426 break; 3427 } 3428 3429 return Ex; 3430} 3431 3432static bool isConstantSizeArrayWithMoreThanOneElement(QualType Ty, 3433 ASTContext &Context) { 3434 // Only handle constant-sized or VLAs, but not flexible members. 3435 if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(Ty)) { 3436 // Only issue the FIXIT for arrays of size > 1. 3437 if (CAT->getSize().getSExtValue() <= 1) 3438 return false; 3439 } else if (!Ty->isVariableArrayType()) { 3440 return false; 3441 } 3442 return true; 3443} 3444 3445// Warn if the user has made the 'size' argument to strlcpy or strlcat 3446// be the size of the source, instead of the destination. 3447void Sema::CheckStrlcpycatArguments(const CallExpr *Call, 3448 IdentifierInfo *FnName) { 3449 3450 // Don't crash if the user has the wrong number of arguments 3451 if (Call->getNumArgs() != 3) 3452 return; 3453 3454 const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context); 3455 const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context); 3456 const Expr *CompareWithSrc = NULL; 3457 3458 // Look for 'strlcpy(dst, x, sizeof(x))' 3459 if (const Expr *Ex = getSizeOfExprArg(SizeArg)) 3460 CompareWithSrc = Ex; 3461 else { 3462 // Look for 'strlcpy(dst, x, strlen(x))' 3463 if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) { 3464 if (SizeCall->isBuiltinCall() == Builtin::BIstrlen 3465 && SizeCall->getNumArgs() == 1) 3466 CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context); 3467 } 3468 } 3469 3470 if (!CompareWithSrc) 3471 return; 3472 3473 // Determine if the argument to sizeof/strlen is equal to the source 3474 // argument. In principle there's all kinds of things you could do 3475 // here, for instance creating an == expression and evaluating it with 3476 // EvaluateAsBooleanCondition, but this uses a more direct technique: 3477 const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg); 3478 if (!SrcArgDRE) 3479 return; 3480 3481 const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc); 3482 if (!CompareWithSrcDRE || 3483 SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl()) 3484 return; 3485 3486 const Expr *OriginalSizeArg = Call->getArg(2); 3487 Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size) 3488 << OriginalSizeArg->getSourceRange() << FnName; 3489 3490 // Output a FIXIT hint if the destination is an array (rather than a 3491 // pointer to an array). This could be enhanced to handle some 3492 // pointers if we know the actual size, like if DstArg is 'array+2' 3493 // we could say 'sizeof(array)-2'. 3494 const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts(); 3495 if (!isConstantSizeArrayWithMoreThanOneElement(DstArg->getType(), Context)) 3496 return; 3497 3498 SmallString<128> sizeString; 3499 llvm::raw_svector_ostream OS(sizeString); 3500 OS << "sizeof("; 3501 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3502 OS << ")"; 3503 3504 Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size) 3505 << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(), 3506 OS.str()); 3507} 3508 3509/// Check if two expressions refer to the same declaration. 3510static bool referToTheSameDecl(const Expr *E1, const Expr *E2) { 3511 if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1)) 3512 if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2)) 3513 return D1->getDecl() == D2->getDecl(); 3514 return false; 3515} 3516 3517static const Expr *getStrlenExprArg(const Expr *E) { 3518 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 3519 const FunctionDecl *FD = CE->getDirectCallee(); 3520 if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen) 3521 return 0; 3522 return CE->getArg(0)->IgnoreParenCasts(); 3523 } 3524 return 0; 3525} 3526 3527// Warn on anti-patterns as the 'size' argument to strncat. 3528// The correct size argument should look like following: 3529// strncat(dst, src, sizeof(dst) - strlen(dest) - 1); 3530void Sema::CheckStrncatArguments(const CallExpr *CE, 3531 IdentifierInfo *FnName) { 3532 // Don't crash if the user has the wrong number of arguments. 3533 if (CE->getNumArgs() < 3) 3534 return; 3535 const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts(); 3536 const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts(); 3537 const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts(); 3538 3539 // Identify common expressions, which are wrongly used as the size argument 3540 // to strncat and may lead to buffer overflows. 3541 unsigned PatternType = 0; 3542 if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) { 3543 // - sizeof(dst) 3544 if (referToTheSameDecl(SizeOfArg, DstArg)) 3545 PatternType = 1; 3546 // - sizeof(src) 3547 else if (referToTheSameDecl(SizeOfArg, SrcArg)) 3548 PatternType = 2; 3549 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) { 3550 if (BE->getOpcode() == BO_Sub) { 3551 const Expr *L = BE->getLHS()->IgnoreParenCasts(); 3552 const Expr *R = BE->getRHS()->IgnoreParenCasts(); 3553 // - sizeof(dst) - strlen(dst) 3554 if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) && 3555 referToTheSameDecl(DstArg, getStrlenExprArg(R))) 3556 PatternType = 1; 3557 // - sizeof(src) - (anything) 3558 else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L))) 3559 PatternType = 2; 3560 } 3561 } 3562 3563 if (PatternType == 0) 3564 return; 3565 3566 // Generate the diagnostic. 3567 SourceLocation SL = LenArg->getLocStart(); 3568 SourceRange SR = LenArg->getSourceRange(); 3569 SourceManager &SM = PP.getSourceManager(); 3570 3571 // If the function is defined as a builtin macro, do not show macro expansion. 3572 if (SM.isMacroArgExpansion(SL)) { 3573 SL = SM.getSpellingLoc(SL); 3574 SR = SourceRange(SM.getSpellingLoc(SR.getBegin()), 3575 SM.getSpellingLoc(SR.getEnd())); 3576 } 3577 3578 // Check if the destination is an array (rather than a pointer to an array). 3579 QualType DstTy = DstArg->getType(); 3580 bool isKnownSizeArray = isConstantSizeArrayWithMoreThanOneElement(DstTy, 3581 Context); 3582 if (!isKnownSizeArray) { 3583 if (PatternType == 1) 3584 Diag(SL, diag::warn_strncat_wrong_size) << SR; 3585 else 3586 Diag(SL, diag::warn_strncat_src_size) << SR; 3587 return; 3588 } 3589 3590 if (PatternType == 1) 3591 Diag(SL, diag::warn_strncat_large_size) << SR; 3592 else 3593 Diag(SL, diag::warn_strncat_src_size) << SR; 3594 3595 SmallString<128> sizeString; 3596 llvm::raw_svector_ostream OS(sizeString); 3597 OS << "sizeof("; 3598 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3599 OS << ") - "; 3600 OS << "strlen("; 3601 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3602 OS << ") - 1"; 3603 3604 Diag(SL, diag::note_strncat_wrong_size) 3605 << FixItHint::CreateReplacement(SR, OS.str()); 3606} 3607 3608//===--- CHECK: Return Address of Stack Variable --------------------------===// 3609 3610static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3611 Decl *ParentDecl); 3612static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars, 3613 Decl *ParentDecl); 3614 3615/// CheckReturnStackAddr - Check if a return statement returns the address 3616/// of a stack variable. 3617void 3618Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType, 3619 SourceLocation ReturnLoc) { 3620 3621 Expr *stackE = 0; 3622 SmallVector<DeclRefExpr *, 8> refVars; 3623 3624 // Perform checking for returned stack addresses, local blocks, 3625 // label addresses or references to temporaries. 3626 if (lhsType->isPointerType() || 3627 (!getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) { 3628 stackE = EvalAddr(RetValExp, refVars, /*ParentDecl=*/0); 3629 } else if (lhsType->isReferenceType()) { 3630 stackE = EvalVal(RetValExp, refVars, /*ParentDecl=*/0); 3631 } 3632 3633 if (stackE == 0) 3634 return; // Nothing suspicious was found. 3635 3636 SourceLocation diagLoc; 3637 SourceRange diagRange; 3638 if (refVars.empty()) { 3639 diagLoc = stackE->getLocStart(); 3640 diagRange = stackE->getSourceRange(); 3641 } else { 3642 // We followed through a reference variable. 'stackE' contains the 3643 // problematic expression but we will warn at the return statement pointing 3644 // at the reference variable. We will later display the "trail" of 3645 // reference variables using notes. 3646 diagLoc = refVars[0]->getLocStart(); 3647 diagRange = refVars[0]->getSourceRange(); 3648 } 3649 3650 if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var. 3651 Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref 3652 : diag::warn_ret_stack_addr) 3653 << DR->getDecl()->getDeclName() << diagRange; 3654 } else if (isa<BlockExpr>(stackE)) { // local block. 3655 Diag(diagLoc, diag::err_ret_local_block) << diagRange; 3656 } else if (isa<AddrLabelExpr>(stackE)) { // address of label. 3657 Diag(diagLoc, diag::warn_ret_addr_label) << diagRange; 3658 } else { // local temporary. 3659 Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref 3660 : diag::warn_ret_local_temp_addr) 3661 << diagRange; 3662 } 3663 3664 // Display the "trail" of reference variables that we followed until we 3665 // found the problematic expression using notes. 3666 for (unsigned i = 0, e = refVars.size(); i != e; ++i) { 3667 VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl()); 3668 // If this var binds to another reference var, show the range of the next 3669 // var, otherwise the var binds to the problematic expression, in which case 3670 // show the range of the expression. 3671 SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange() 3672 : stackE->getSourceRange(); 3673 Diag(VD->getLocation(), diag::note_ref_var_local_bind) 3674 << VD->getDeclName() << range; 3675 } 3676} 3677 3678/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that 3679/// check if the expression in a return statement evaluates to an address 3680/// to a location on the stack, a local block, an address of a label, or a 3681/// reference to local temporary. The recursion is used to traverse the 3682/// AST of the return expression, with recursion backtracking when we 3683/// encounter a subexpression that (1) clearly does not lead to one of the 3684/// above problematic expressions (2) is something we cannot determine leads to 3685/// a problematic expression based on such local checking. 3686/// 3687/// Both EvalAddr and EvalVal follow through reference variables to evaluate 3688/// the expression that they point to. Such variables are added to the 3689/// 'refVars' vector so that we know what the reference variable "trail" was. 3690/// 3691/// EvalAddr processes expressions that are pointers that are used as 3692/// references (and not L-values). EvalVal handles all other values. 3693/// At the base case of the recursion is a check for the above problematic 3694/// expressions. 3695/// 3696/// This implementation handles: 3697/// 3698/// * pointer-to-pointer casts 3699/// * implicit conversions from array references to pointers 3700/// * taking the address of fields 3701/// * arbitrary interplay between "&" and "*" operators 3702/// * pointer arithmetic from an address of a stack variable 3703/// * taking the address of an array element where the array is on the stack 3704static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3705 Decl *ParentDecl) { 3706 if (E->isTypeDependent()) 3707 return NULL; 3708 3709 // We should only be called for evaluating pointer expressions. 3710 assert((E->getType()->isAnyPointerType() || 3711 E->getType()->isBlockPointerType() || 3712 E->getType()->isObjCQualifiedIdType()) && 3713 "EvalAddr only works on pointers"); 3714 3715 E = E->IgnoreParens(); 3716 3717 // Our "symbolic interpreter" is just a dispatch off the currently 3718 // viewed AST node. We then recursively traverse the AST by calling 3719 // EvalAddr and EvalVal appropriately. 3720 switch (E->getStmtClass()) { 3721 case Stmt::DeclRefExprClass: { 3722 DeclRefExpr *DR = cast<DeclRefExpr>(E); 3723 3724 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) 3725 // If this is a reference variable, follow through to the expression that 3726 // it points to. 3727 if (V->hasLocalStorage() && 3728 V->getType()->isReferenceType() && V->hasInit()) { 3729 // Add the reference variable to the "trail". 3730 refVars.push_back(DR); 3731 return EvalAddr(V->getInit(), refVars, ParentDecl); 3732 } 3733 3734 return NULL; 3735 } 3736 3737 case Stmt::UnaryOperatorClass: { 3738 // The only unary operator that make sense to handle here 3739 // is AddrOf. All others don't make sense as pointers. 3740 UnaryOperator *U = cast<UnaryOperator>(E); 3741 3742 if (U->getOpcode() == UO_AddrOf) 3743 return EvalVal(U->getSubExpr(), refVars, ParentDecl); 3744 else 3745 return NULL; 3746 } 3747 3748 case Stmt::BinaryOperatorClass: { 3749 // Handle pointer arithmetic. All other binary operators are not valid 3750 // in this context. 3751 BinaryOperator *B = cast<BinaryOperator>(E); 3752 BinaryOperatorKind op = B->getOpcode(); 3753 3754 if (op != BO_Add && op != BO_Sub) 3755 return NULL; 3756 3757 Expr *Base = B->getLHS(); 3758 3759 // Determine which argument is the real pointer base. It could be 3760 // the RHS argument instead of the LHS. 3761 if (!Base->getType()->isPointerType()) Base = B->getRHS(); 3762 3763 assert (Base->getType()->isPointerType()); 3764 return EvalAddr(Base, refVars, ParentDecl); 3765 } 3766 3767 // For conditional operators we need to see if either the LHS or RHS are 3768 // valid DeclRefExpr*s. If one of them is valid, we return it. 3769 case Stmt::ConditionalOperatorClass: { 3770 ConditionalOperator *C = cast<ConditionalOperator>(E); 3771 3772 // Handle the GNU extension for missing LHS. 3773 if (Expr *lhsExpr = C->getLHS()) { 3774 // In C++, we can have a throw-expression, which has 'void' type. 3775 if (!lhsExpr->getType()->isVoidType()) 3776 if (Expr* LHS = EvalAddr(lhsExpr, refVars, ParentDecl)) 3777 return LHS; 3778 } 3779 3780 // In C++, we can have a throw-expression, which has 'void' type. 3781 if (C->getRHS()->getType()->isVoidType()) 3782 return NULL; 3783 3784 return EvalAddr(C->getRHS(), refVars, ParentDecl); 3785 } 3786 3787 case Stmt::BlockExprClass: 3788 if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures()) 3789 return E; // local block. 3790 return NULL; 3791 3792 case Stmt::AddrLabelExprClass: 3793 return E; // address of label. 3794 3795 case Stmt::ExprWithCleanupsClass: 3796 return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars, 3797 ParentDecl); 3798 3799 // For casts, we need to handle conversions from arrays to 3800 // pointer values, and pointer-to-pointer conversions. 3801 case Stmt::ImplicitCastExprClass: 3802 case Stmt::CStyleCastExprClass: 3803 case Stmt::CXXFunctionalCastExprClass: 3804 case Stmt::ObjCBridgedCastExprClass: 3805 case Stmt::CXXStaticCastExprClass: 3806 case Stmt::CXXDynamicCastExprClass: 3807 case Stmt::CXXConstCastExprClass: 3808 case Stmt::CXXReinterpretCastExprClass: { 3809 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr(); 3810 switch (cast<CastExpr>(E)->getCastKind()) { 3811 case CK_BitCast: 3812 case CK_LValueToRValue: 3813 case CK_NoOp: 3814 case CK_BaseToDerived: 3815 case CK_DerivedToBase: 3816 case CK_UncheckedDerivedToBase: 3817 case CK_Dynamic: 3818 case CK_CPointerToObjCPointerCast: 3819 case CK_BlockPointerToObjCPointerCast: 3820 case CK_AnyPointerToBlockPointerCast: 3821 return EvalAddr(SubExpr, refVars, ParentDecl); 3822 3823 case CK_ArrayToPointerDecay: 3824 return EvalVal(SubExpr, refVars, ParentDecl); 3825 3826 default: 3827 return 0; 3828 } 3829 } 3830 3831 case Stmt::MaterializeTemporaryExprClass: 3832 if (Expr *Result = EvalAddr( 3833 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 3834 refVars, ParentDecl)) 3835 return Result; 3836 3837 return E; 3838 3839 // Everything else: we simply don't reason about them. 3840 default: 3841 return NULL; 3842 } 3843} 3844 3845 3846/// EvalVal - This function is complements EvalAddr in the mutual recursion. 3847/// See the comments for EvalAddr for more details. 3848static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3849 Decl *ParentDecl) { 3850do { 3851 // We should only be called for evaluating non-pointer expressions, or 3852 // expressions with a pointer type that are not used as references but instead 3853 // are l-values (e.g., DeclRefExpr with a pointer type). 3854 3855 // Our "symbolic interpreter" is just a dispatch off the currently 3856 // viewed AST node. We then recursively traverse the AST by calling 3857 // EvalAddr and EvalVal appropriately. 3858 3859 E = E->IgnoreParens(); 3860 switch (E->getStmtClass()) { 3861 case Stmt::ImplicitCastExprClass: { 3862 ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E); 3863 if (IE->getValueKind() == VK_LValue) { 3864 E = IE->getSubExpr(); 3865 continue; 3866 } 3867 return NULL; 3868 } 3869 3870 case Stmt::ExprWithCleanupsClass: 3871 return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,ParentDecl); 3872 3873 case Stmt::DeclRefExprClass: { 3874 // When we hit a DeclRefExpr we are looking at code that refers to a 3875 // variable's name. If it's not a reference variable we check if it has 3876 // local storage within the function, and if so, return the expression. 3877 DeclRefExpr *DR = cast<DeclRefExpr>(E); 3878 3879 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) { 3880 // Check if it refers to itself, e.g. "int& i = i;". 3881 if (V == ParentDecl) 3882 return DR; 3883 3884 if (V->hasLocalStorage()) { 3885 if (!V->getType()->isReferenceType()) 3886 return DR; 3887 3888 // Reference variable, follow through to the expression that 3889 // it points to. 3890 if (V->hasInit()) { 3891 // Add the reference variable to the "trail". 3892 refVars.push_back(DR); 3893 return EvalVal(V->getInit(), refVars, V); 3894 } 3895 } 3896 } 3897 3898 return NULL; 3899 } 3900 3901 case Stmt::UnaryOperatorClass: { 3902 // The only unary operator that make sense to handle here 3903 // is Deref. All others don't resolve to a "name." This includes 3904 // handling all sorts of rvalues passed to a unary operator. 3905 UnaryOperator *U = cast<UnaryOperator>(E); 3906 3907 if (U->getOpcode() == UO_Deref) 3908 return EvalAddr(U->getSubExpr(), refVars, ParentDecl); 3909 3910 return NULL; 3911 } 3912 3913 case Stmt::ArraySubscriptExprClass: { 3914 // Array subscripts are potential references to data on the stack. We 3915 // retrieve the DeclRefExpr* for the array variable if it indeed 3916 // has local storage. 3917 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars,ParentDecl); 3918 } 3919 3920 case Stmt::ConditionalOperatorClass: { 3921 // For conditional operators we need to see if either the LHS or RHS are 3922 // non-NULL Expr's. If one is non-NULL, we return it. 3923 ConditionalOperator *C = cast<ConditionalOperator>(E); 3924 3925 // Handle the GNU extension for missing LHS. 3926 if (Expr *lhsExpr = C->getLHS()) 3927 if (Expr *LHS = EvalVal(lhsExpr, refVars, ParentDecl)) 3928 return LHS; 3929 3930 return EvalVal(C->getRHS(), refVars, ParentDecl); 3931 } 3932 3933 // Accesses to members are potential references to data on the stack. 3934 case Stmt::MemberExprClass: { 3935 MemberExpr *M = cast<MemberExpr>(E); 3936 3937 // Check for indirect access. We only want direct field accesses. 3938 if (M->isArrow()) 3939 return NULL; 3940 3941 // Check whether the member type is itself a reference, in which case 3942 // we're not going to refer to the member, but to what the member refers to. 3943 if (M->getMemberDecl()->getType()->isReferenceType()) 3944 return NULL; 3945 3946 return EvalVal(M->getBase(), refVars, ParentDecl); 3947 } 3948 3949 case Stmt::MaterializeTemporaryExprClass: 3950 if (Expr *Result = EvalVal( 3951 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 3952 refVars, ParentDecl)) 3953 return Result; 3954 3955 return E; 3956 3957 default: 3958 // Check that we don't return or take the address of a reference to a 3959 // temporary. This is only useful in C++. 3960 if (!E->isTypeDependent() && E->isRValue()) 3961 return E; 3962 3963 // Everything else: we simply don't reason about them. 3964 return NULL; 3965 } 3966} while (true); 3967} 3968 3969//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===// 3970 3971/// Check for comparisons of floating point operands using != and ==. 3972/// Issue a warning if these are no self-comparisons, as they are not likely 3973/// to do what the programmer intended. 3974void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) { 3975 Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts(); 3976 Expr* RightExprSansParen = RHS->IgnoreParenImpCasts(); 3977 3978 // Special case: check for x == x (which is OK). 3979 // Do not emit warnings for such cases. 3980 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen)) 3981 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen)) 3982 if (DRL->getDecl() == DRR->getDecl()) 3983 return; 3984 3985 3986 // Special case: check for comparisons against literals that can be exactly 3987 // represented by APFloat. In such cases, do not emit a warning. This 3988 // is a heuristic: often comparison against such literals are used to 3989 // detect if a value in a variable has not changed. This clearly can 3990 // lead to false negatives. 3991 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) { 3992 if (FLL->isExact()) 3993 return; 3994 } else 3995 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)) 3996 if (FLR->isExact()) 3997 return; 3998 3999 // Check for comparisons with builtin types. 4000 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen)) 4001 if (CL->isBuiltinCall()) 4002 return; 4003 4004 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen)) 4005 if (CR->isBuiltinCall()) 4006 return; 4007 4008 // Emit the diagnostic. 4009 Diag(Loc, diag::warn_floatingpoint_eq) 4010 << LHS->getSourceRange() << RHS->getSourceRange(); 4011} 4012 4013//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===// 4014//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===// 4015 4016namespace { 4017 4018/// Structure recording the 'active' range of an integer-valued 4019/// expression. 4020struct IntRange { 4021 /// The number of bits active in the int. 4022 unsigned Width; 4023 4024 /// True if the int is known not to have negative values. 4025 bool NonNegative; 4026 4027 IntRange(unsigned Width, bool NonNegative) 4028 : Width(Width), NonNegative(NonNegative) 4029 {} 4030 4031 /// Returns the range of the bool type. 4032 static IntRange forBoolType() { 4033 return IntRange(1, true); 4034 } 4035 4036 /// Returns the range of an opaque value of the given integral type. 4037 static IntRange forValueOfType(ASTContext &C, QualType T) { 4038 return forValueOfCanonicalType(C, 4039 T->getCanonicalTypeInternal().getTypePtr()); 4040 } 4041 4042 /// Returns the range of an opaque value of a canonical integral type. 4043 static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) { 4044 assert(T->isCanonicalUnqualified()); 4045 4046 if (const VectorType *VT = dyn_cast<VectorType>(T)) 4047 T = VT->getElementType().getTypePtr(); 4048 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 4049 T = CT->getElementType().getTypePtr(); 4050 4051 // For enum types, use the known bit width of the enumerators. 4052 if (const EnumType *ET = dyn_cast<EnumType>(T)) { 4053 EnumDecl *Enum = ET->getDecl(); 4054 if (!Enum->isCompleteDefinition()) 4055 return IntRange(C.getIntWidth(QualType(T, 0)), false); 4056 4057 unsigned NumPositive = Enum->getNumPositiveBits(); 4058 unsigned NumNegative = Enum->getNumNegativeBits(); 4059 4060 if (NumNegative == 0) 4061 return IntRange(NumPositive, true/*NonNegative*/); 4062 else 4063 return IntRange(std::max(NumPositive + 1, NumNegative), 4064 false/*NonNegative*/); 4065 } 4066 4067 const BuiltinType *BT = cast<BuiltinType>(T); 4068 assert(BT->isInteger()); 4069 4070 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 4071 } 4072 4073 /// Returns the "target" range of a canonical integral type, i.e. 4074 /// the range of values expressible in the type. 4075 /// 4076 /// This matches forValueOfCanonicalType except that enums have the 4077 /// full range of their type, not the range of their enumerators. 4078 static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) { 4079 assert(T->isCanonicalUnqualified()); 4080 4081 if (const VectorType *VT = dyn_cast<VectorType>(T)) 4082 T = VT->getElementType().getTypePtr(); 4083 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 4084 T = CT->getElementType().getTypePtr(); 4085 if (const EnumType *ET = dyn_cast<EnumType>(T)) 4086 T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr(); 4087 4088 const BuiltinType *BT = cast<BuiltinType>(T); 4089 assert(BT->isInteger()); 4090 4091 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 4092 } 4093 4094 /// Returns the supremum of two ranges: i.e. their conservative merge. 4095 static IntRange join(IntRange L, IntRange R) { 4096 return IntRange(std::max(L.Width, R.Width), 4097 L.NonNegative && R.NonNegative); 4098 } 4099 4100 /// Returns the infinum of two ranges: i.e. their aggressive merge. 4101 static IntRange meet(IntRange L, IntRange R) { 4102 return IntRange(std::min(L.Width, R.Width), 4103 L.NonNegative || R.NonNegative); 4104 } 4105}; 4106 4107static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, 4108 unsigned MaxWidth) { 4109 if (value.isSigned() && value.isNegative()) 4110 return IntRange(value.getMinSignedBits(), false); 4111 4112 if (value.getBitWidth() > MaxWidth) 4113 value = value.trunc(MaxWidth); 4114 4115 // isNonNegative() just checks the sign bit without considering 4116 // signedness. 4117 return IntRange(value.getActiveBits(), true); 4118} 4119 4120static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty, 4121 unsigned MaxWidth) { 4122 if (result.isInt()) 4123 return GetValueRange(C, result.getInt(), MaxWidth); 4124 4125 if (result.isVector()) { 4126 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth); 4127 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) { 4128 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth); 4129 R = IntRange::join(R, El); 4130 } 4131 return R; 4132 } 4133 4134 if (result.isComplexInt()) { 4135 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth); 4136 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth); 4137 return IntRange::join(R, I); 4138 } 4139 4140 // This can happen with lossless casts to intptr_t of "based" lvalues. 4141 // Assume it might use arbitrary bits. 4142 // FIXME: The only reason we need to pass the type in here is to get 4143 // the sign right on this one case. It would be nice if APValue 4144 // preserved this. 4145 assert(result.isLValue() || result.isAddrLabelDiff()); 4146 return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType()); 4147} 4148 4149/// Pseudo-evaluate the given integer expression, estimating the 4150/// range of values it might take. 4151/// 4152/// \param MaxWidth - the width to which the value will be truncated 4153static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) { 4154 E = E->IgnoreParens(); 4155 4156 // Try a full evaluation first. 4157 Expr::EvalResult result; 4158 if (E->EvaluateAsRValue(result, C)) 4159 return GetValueRange(C, result.Val, E->getType(), MaxWidth); 4160 4161 // I think we only want to look through implicit casts here; if the 4162 // user has an explicit widening cast, we should treat the value as 4163 // being of the new, wider type. 4164 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) { 4165 if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue) 4166 return GetExprRange(C, CE->getSubExpr(), MaxWidth); 4167 4168 IntRange OutputTypeRange = IntRange::forValueOfType(C, CE->getType()); 4169 4170 bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast); 4171 4172 // Assume that non-integer casts can span the full range of the type. 4173 if (!isIntegerCast) 4174 return OutputTypeRange; 4175 4176 IntRange SubRange 4177 = GetExprRange(C, CE->getSubExpr(), 4178 std::min(MaxWidth, OutputTypeRange.Width)); 4179 4180 // Bail out if the subexpr's range is as wide as the cast type. 4181 if (SubRange.Width >= OutputTypeRange.Width) 4182 return OutputTypeRange; 4183 4184 // Otherwise, we take the smaller width, and we're non-negative if 4185 // either the output type or the subexpr is. 4186 return IntRange(SubRange.Width, 4187 SubRange.NonNegative || OutputTypeRange.NonNegative); 4188 } 4189 4190 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 4191 // If we can fold the condition, just take that operand. 4192 bool CondResult; 4193 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C)) 4194 return GetExprRange(C, CondResult ? CO->getTrueExpr() 4195 : CO->getFalseExpr(), 4196 MaxWidth); 4197 4198 // Otherwise, conservatively merge. 4199 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth); 4200 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth); 4201 return IntRange::join(L, R); 4202 } 4203 4204 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 4205 switch (BO->getOpcode()) { 4206 4207 // Boolean-valued operations are single-bit and positive. 4208 case BO_LAnd: 4209 case BO_LOr: 4210 case BO_LT: 4211 case BO_GT: 4212 case BO_LE: 4213 case BO_GE: 4214 case BO_EQ: 4215 case BO_NE: 4216 return IntRange::forBoolType(); 4217 4218 // The type of the assignments is the type of the LHS, so the RHS 4219 // is not necessarily the same type. 4220 case BO_MulAssign: 4221 case BO_DivAssign: 4222 case BO_RemAssign: 4223 case BO_AddAssign: 4224 case BO_SubAssign: 4225 case BO_XorAssign: 4226 case BO_OrAssign: 4227 // TODO: bitfields? 4228 return IntRange::forValueOfType(C, E->getType()); 4229 4230 // Simple assignments just pass through the RHS, which will have 4231 // been coerced to the LHS type. 4232 case BO_Assign: 4233 // TODO: bitfields? 4234 return GetExprRange(C, BO->getRHS(), MaxWidth); 4235 4236 // Operations with opaque sources are black-listed. 4237 case BO_PtrMemD: 4238 case BO_PtrMemI: 4239 return IntRange::forValueOfType(C, E->getType()); 4240 4241 // Bitwise-and uses the *infinum* of the two source ranges. 4242 case BO_And: 4243 case BO_AndAssign: 4244 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth), 4245 GetExprRange(C, BO->getRHS(), MaxWidth)); 4246 4247 // Left shift gets black-listed based on a judgement call. 4248 case BO_Shl: 4249 // ...except that we want to treat '1 << (blah)' as logically 4250 // positive. It's an important idiom. 4251 if (IntegerLiteral *I 4252 = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) { 4253 if (I->getValue() == 1) { 4254 IntRange R = IntRange::forValueOfType(C, E->getType()); 4255 return IntRange(R.Width, /*NonNegative*/ true); 4256 } 4257 } 4258 // fallthrough 4259 4260 case BO_ShlAssign: 4261 return IntRange::forValueOfType(C, E->getType()); 4262 4263 // Right shift by a constant can narrow its left argument. 4264 case BO_Shr: 4265 case BO_ShrAssign: { 4266 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 4267 4268 // If the shift amount is a positive constant, drop the width by 4269 // that much. 4270 llvm::APSInt shift; 4271 if (BO->getRHS()->isIntegerConstantExpr(shift, C) && 4272 shift.isNonNegative()) { 4273 unsigned zext = shift.getZExtValue(); 4274 if (zext >= L.Width) 4275 L.Width = (L.NonNegative ? 0 : 1); 4276 else 4277 L.Width -= zext; 4278 } 4279 4280 return L; 4281 } 4282 4283 // Comma acts as its right operand. 4284 case BO_Comma: 4285 return GetExprRange(C, BO->getRHS(), MaxWidth); 4286 4287 // Black-list pointer subtractions. 4288 case BO_Sub: 4289 if (BO->getLHS()->getType()->isPointerType()) 4290 return IntRange::forValueOfType(C, E->getType()); 4291 break; 4292 4293 // The width of a division result is mostly determined by the size 4294 // of the LHS. 4295 case BO_Div: { 4296 // Don't 'pre-truncate' the operands. 4297 unsigned opWidth = C.getIntWidth(E->getType()); 4298 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 4299 4300 // If the divisor is constant, use that. 4301 llvm::APSInt divisor; 4302 if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) { 4303 unsigned log2 = divisor.logBase2(); // floor(log_2(divisor)) 4304 if (log2 >= L.Width) 4305 L.Width = (L.NonNegative ? 0 : 1); 4306 else 4307 L.Width = std::min(L.Width - log2, MaxWidth); 4308 return L; 4309 } 4310 4311 // Otherwise, just use the LHS's width. 4312 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 4313 return IntRange(L.Width, L.NonNegative && R.NonNegative); 4314 } 4315 4316 // The result of a remainder can't be larger than the result of 4317 // either side. 4318 case BO_Rem: { 4319 // Don't 'pre-truncate' the operands. 4320 unsigned opWidth = C.getIntWidth(E->getType()); 4321 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 4322 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 4323 4324 IntRange meet = IntRange::meet(L, R); 4325 meet.Width = std::min(meet.Width, MaxWidth); 4326 return meet; 4327 } 4328 4329 // The default behavior is okay for these. 4330 case BO_Mul: 4331 case BO_Add: 4332 case BO_Xor: 4333 case BO_Or: 4334 break; 4335 } 4336 4337 // The default case is to treat the operation as if it were closed 4338 // on the narrowest type that encompasses both operands. 4339 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 4340 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth); 4341 return IntRange::join(L, R); 4342 } 4343 4344 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 4345 switch (UO->getOpcode()) { 4346 // Boolean-valued operations are white-listed. 4347 case UO_LNot: 4348 return IntRange::forBoolType(); 4349 4350 // Operations with opaque sources are black-listed. 4351 case UO_Deref: 4352 case UO_AddrOf: // should be impossible 4353 return IntRange::forValueOfType(C, E->getType()); 4354 4355 default: 4356 return GetExprRange(C, UO->getSubExpr(), MaxWidth); 4357 } 4358 } 4359 4360 if (dyn_cast<OffsetOfExpr>(E)) { 4361 IntRange::forValueOfType(C, E->getType()); 4362 } 4363 4364 if (FieldDecl *BitField = E->getSourceBitField()) 4365 return IntRange(BitField->getBitWidthValue(C), 4366 BitField->getType()->isUnsignedIntegerOrEnumerationType()); 4367 4368 return IntRange::forValueOfType(C, E->getType()); 4369} 4370 4371static IntRange GetExprRange(ASTContext &C, Expr *E) { 4372 return GetExprRange(C, E, C.getIntWidth(E->getType())); 4373} 4374 4375/// Checks whether the given value, which currently has the given 4376/// source semantics, has the same value when coerced through the 4377/// target semantics. 4378static bool IsSameFloatAfterCast(const llvm::APFloat &value, 4379 const llvm::fltSemantics &Src, 4380 const llvm::fltSemantics &Tgt) { 4381 llvm::APFloat truncated = value; 4382 4383 bool ignored; 4384 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored); 4385 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored); 4386 4387 return truncated.bitwiseIsEqual(value); 4388} 4389 4390/// Checks whether the given value, which currently has the given 4391/// source semantics, has the same value when coerced through the 4392/// target semantics. 4393/// 4394/// The value might be a vector of floats (or a complex number). 4395static bool IsSameFloatAfterCast(const APValue &value, 4396 const llvm::fltSemantics &Src, 4397 const llvm::fltSemantics &Tgt) { 4398 if (value.isFloat()) 4399 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt); 4400 4401 if (value.isVector()) { 4402 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i) 4403 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt)) 4404 return false; 4405 return true; 4406 } 4407 4408 assert(value.isComplexFloat()); 4409 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) && 4410 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt)); 4411} 4412 4413static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC); 4414 4415static bool IsZero(Sema &S, Expr *E) { 4416 // Suppress cases where we are comparing against an enum constant. 4417 if (const DeclRefExpr *DR = 4418 dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts())) 4419 if (isa<EnumConstantDecl>(DR->getDecl())) 4420 return false; 4421 4422 // Suppress cases where the '0' value is expanded from a macro. 4423 if (E->getLocStart().isMacroID()) 4424 return false; 4425 4426 llvm::APSInt Value; 4427 return E->isIntegerConstantExpr(Value, S.Context) && Value == 0; 4428} 4429 4430static bool HasEnumType(Expr *E) { 4431 // Strip off implicit integral promotions. 4432 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 4433 if (ICE->getCastKind() != CK_IntegralCast && 4434 ICE->getCastKind() != CK_NoOp) 4435 break; 4436 E = ICE->getSubExpr(); 4437 } 4438 4439 return E->getType()->isEnumeralType(); 4440} 4441 4442static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) { 4443 BinaryOperatorKind op = E->getOpcode(); 4444 if (E->isValueDependent()) 4445 return; 4446 4447 if (op == BO_LT && IsZero(S, E->getRHS())) { 4448 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 4449 << "< 0" << "false" << HasEnumType(E->getLHS()) 4450 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4451 } else if (op == BO_GE && IsZero(S, E->getRHS())) { 4452 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 4453 << ">= 0" << "true" << HasEnumType(E->getLHS()) 4454 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4455 } else if (op == BO_GT && IsZero(S, E->getLHS())) { 4456 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 4457 << "0 >" << "false" << HasEnumType(E->getRHS()) 4458 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4459 } else if (op == BO_LE && IsZero(S, E->getLHS())) { 4460 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 4461 << "0 <=" << "true" << HasEnumType(E->getRHS()) 4462 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4463 } 4464} 4465 4466static void DiagnoseOutOfRangeComparison(Sema &S, BinaryOperator *E, 4467 Expr *Constant, Expr *Other, 4468 llvm::APSInt Value, 4469 bool RhsConstant) { 4470 // 0 values are handled later by CheckTrivialUnsignedComparison(). 4471 if (Value == 0) 4472 return; 4473 4474 BinaryOperatorKind op = E->getOpcode(); 4475 QualType OtherT = Other->getType(); 4476 QualType ConstantT = Constant->getType(); 4477 QualType CommonT = E->getLHS()->getType(); 4478 if (S.Context.hasSameUnqualifiedType(OtherT, ConstantT)) 4479 return; 4480 assert((OtherT->isIntegerType() && ConstantT->isIntegerType()) 4481 && "comparison with non-integer type"); 4482 4483 bool ConstantSigned = ConstantT->isSignedIntegerType(); 4484 bool CommonSigned = CommonT->isSignedIntegerType(); 4485 4486 bool EqualityOnly = false; 4487 4488 // TODO: Investigate using GetExprRange() to get tighter bounds on 4489 // on the bit ranges. 4490 IntRange OtherRange = IntRange::forValueOfType(S.Context, OtherT); 4491 unsigned OtherWidth = OtherRange.Width; 4492 4493 if (CommonSigned) { 4494 // The common type is signed, therefore no signed to unsigned conversion. 4495 if (!OtherRange.NonNegative) { 4496 // Check that the constant is representable in type OtherT. 4497 if (ConstantSigned) { 4498 if (OtherWidth >= Value.getMinSignedBits()) 4499 return; 4500 } else { // !ConstantSigned 4501 if (OtherWidth >= Value.getActiveBits() + 1) 4502 return; 4503 } 4504 } else { // !OtherSigned 4505 // Check that the constant is representable in type OtherT. 4506 // Negative values are out of range. 4507 if (ConstantSigned) { 4508 if (Value.isNonNegative() && OtherWidth >= Value.getActiveBits()) 4509 return; 4510 } else { // !ConstantSigned 4511 if (OtherWidth >= Value.getActiveBits()) 4512 return; 4513 } 4514 } 4515 } else { // !CommonSigned 4516 if (OtherRange.NonNegative) { 4517 if (OtherWidth >= Value.getActiveBits()) 4518 return; 4519 } else if (!OtherRange.NonNegative && !ConstantSigned) { 4520 // Check to see if the constant is representable in OtherT. 4521 if (OtherWidth > Value.getActiveBits()) 4522 return; 4523 // Check to see if the constant is equivalent to a negative value 4524 // cast to CommonT. 4525 if (S.Context.getIntWidth(ConstantT) == S.Context.getIntWidth(CommonT) && 4526 Value.isNegative() && Value.getMinSignedBits() <= OtherWidth) 4527 return; 4528 // The constant value rests between values that OtherT can represent after 4529 // conversion. Relational comparison still works, but equality 4530 // comparisons will be tautological. 4531 EqualityOnly = true; 4532 } else { // OtherSigned && ConstantSigned 4533 assert(0 && "Two signed types converted to unsigned types."); 4534 } 4535 } 4536 4537 bool PositiveConstant = !ConstantSigned || Value.isNonNegative(); 4538 4539 bool IsTrue = true; 4540 if (op == BO_EQ || op == BO_NE) { 4541 IsTrue = op == BO_NE; 4542 } else if (EqualityOnly) { 4543 return; 4544 } else if (RhsConstant) { 4545 if (op == BO_GT || op == BO_GE) 4546 IsTrue = !PositiveConstant; 4547 else // op == BO_LT || op == BO_LE 4548 IsTrue = PositiveConstant; 4549 } else { 4550 if (op == BO_LT || op == BO_LE) 4551 IsTrue = !PositiveConstant; 4552 else // op == BO_GT || op == BO_GE 4553 IsTrue = PositiveConstant; 4554 } 4555 4556 // If this is a comparison to an enum constant, include that 4557 // constant in the diagnostic. 4558 const EnumConstantDecl *ED = 0; 4559 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Constant)) 4560 ED = dyn_cast<EnumConstantDecl>(DR->getDecl()); 4561 4562 SmallString<64> PrettySourceValue; 4563 llvm::raw_svector_ostream OS(PrettySourceValue); 4564 if (ED) 4565 OS << '\'' << *ED << "' (" << Value << ")"; 4566 else 4567 OS << Value; 4568 4569 S.Diag(E->getOperatorLoc(), diag::warn_out_of_range_compare) 4570 << OS.str() << OtherT << IsTrue 4571 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4572} 4573 4574/// Analyze the operands of the given comparison. Implements the 4575/// fallback case from AnalyzeComparison. 4576static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) { 4577 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 4578 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 4579} 4580 4581/// \brief Implements -Wsign-compare. 4582/// 4583/// \param E the binary operator to check for warnings 4584static void AnalyzeComparison(Sema &S, BinaryOperator *E) { 4585 // The type the comparison is being performed in. 4586 QualType T = E->getLHS()->getType(); 4587 assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType()) 4588 && "comparison with mismatched types"); 4589 if (E->isValueDependent()) 4590 return AnalyzeImpConvsInComparison(S, E); 4591 4592 Expr *LHS = E->getLHS()->IgnoreParenImpCasts(); 4593 Expr *RHS = E->getRHS()->IgnoreParenImpCasts(); 4594 4595 bool IsComparisonConstant = false; 4596 4597 // Check whether an integer constant comparison results in a value 4598 // of 'true' or 'false'. 4599 if (T->isIntegralType(S.Context)) { 4600 llvm::APSInt RHSValue; 4601 bool IsRHSIntegralLiteral = 4602 RHS->isIntegerConstantExpr(RHSValue, S.Context); 4603 llvm::APSInt LHSValue; 4604 bool IsLHSIntegralLiteral = 4605 LHS->isIntegerConstantExpr(LHSValue, S.Context); 4606 if (IsRHSIntegralLiteral && !IsLHSIntegralLiteral) 4607 DiagnoseOutOfRangeComparison(S, E, RHS, LHS, RHSValue, true); 4608 else if (!IsRHSIntegralLiteral && IsLHSIntegralLiteral) 4609 DiagnoseOutOfRangeComparison(S, E, LHS, RHS, LHSValue, false); 4610 else 4611 IsComparisonConstant = 4612 (IsRHSIntegralLiteral && IsLHSIntegralLiteral); 4613 } else if (!T->hasUnsignedIntegerRepresentation()) 4614 IsComparisonConstant = E->isIntegerConstantExpr(S.Context); 4615 4616 // We don't do anything special if this isn't an unsigned integral 4617 // comparison: we're only interested in integral comparisons, and 4618 // signed comparisons only happen in cases we don't care to warn about. 4619 // 4620 // We also don't care about value-dependent expressions or expressions 4621 // whose result is a constant. 4622 if (!T->hasUnsignedIntegerRepresentation() || IsComparisonConstant) 4623 return AnalyzeImpConvsInComparison(S, E); 4624 4625 // Check to see if one of the (unmodified) operands is of different 4626 // signedness. 4627 Expr *signedOperand, *unsignedOperand; 4628 if (LHS->getType()->hasSignedIntegerRepresentation()) { 4629 assert(!RHS->getType()->hasSignedIntegerRepresentation() && 4630 "unsigned comparison between two signed integer expressions?"); 4631 signedOperand = LHS; 4632 unsignedOperand = RHS; 4633 } else if (RHS->getType()->hasSignedIntegerRepresentation()) { 4634 signedOperand = RHS; 4635 unsignedOperand = LHS; 4636 } else { 4637 CheckTrivialUnsignedComparison(S, E); 4638 return AnalyzeImpConvsInComparison(S, E); 4639 } 4640 4641 // Otherwise, calculate the effective range of the signed operand. 4642 IntRange signedRange = GetExprRange(S.Context, signedOperand); 4643 4644 // Go ahead and analyze implicit conversions in the operands. Note 4645 // that we skip the implicit conversions on both sides. 4646 AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc()); 4647 AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc()); 4648 4649 // If the signed range is non-negative, -Wsign-compare won't fire, 4650 // but we should still check for comparisons which are always true 4651 // or false. 4652 if (signedRange.NonNegative) 4653 return CheckTrivialUnsignedComparison(S, E); 4654 4655 // For (in)equality comparisons, if the unsigned operand is a 4656 // constant which cannot collide with a overflowed signed operand, 4657 // then reinterpreting the signed operand as unsigned will not 4658 // change the result of the comparison. 4659 if (E->isEqualityOp()) { 4660 unsigned comparisonWidth = S.Context.getIntWidth(T); 4661 IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand); 4662 4663 // We should never be unable to prove that the unsigned operand is 4664 // non-negative. 4665 assert(unsignedRange.NonNegative && "unsigned range includes negative?"); 4666 4667 if (unsignedRange.Width < comparisonWidth) 4668 return; 4669 } 4670 4671 S.DiagRuntimeBehavior(E->getOperatorLoc(), E, 4672 S.PDiag(diag::warn_mixed_sign_comparison) 4673 << LHS->getType() << RHS->getType() 4674 << LHS->getSourceRange() << RHS->getSourceRange()); 4675} 4676 4677/// Analyzes an attempt to assign the given value to a bitfield. 4678/// 4679/// Returns true if there was something fishy about the attempt. 4680static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init, 4681 SourceLocation InitLoc) { 4682 assert(Bitfield->isBitField()); 4683 if (Bitfield->isInvalidDecl()) 4684 return false; 4685 4686 // White-list bool bitfields. 4687 if (Bitfield->getType()->isBooleanType()) 4688 return false; 4689 4690 // Ignore value- or type-dependent expressions. 4691 if (Bitfield->getBitWidth()->isValueDependent() || 4692 Bitfield->getBitWidth()->isTypeDependent() || 4693 Init->isValueDependent() || 4694 Init->isTypeDependent()) 4695 return false; 4696 4697 Expr *OriginalInit = Init->IgnoreParenImpCasts(); 4698 4699 llvm::APSInt Value; 4700 if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects)) 4701 return false; 4702 4703 unsigned OriginalWidth = Value.getBitWidth(); 4704 unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context); 4705 4706 if (OriginalWidth <= FieldWidth) 4707 return false; 4708 4709 // Compute the value which the bitfield will contain. 4710 llvm::APSInt TruncatedValue = Value.trunc(FieldWidth); 4711 TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType()); 4712 4713 // Check whether the stored value is equal to the original value. 4714 TruncatedValue = TruncatedValue.extend(OriginalWidth); 4715 if (llvm::APSInt::isSameValue(Value, TruncatedValue)) 4716 return false; 4717 4718 // Special-case bitfields of width 1: booleans are naturally 0/1, and 4719 // therefore don't strictly fit into a signed bitfield of width 1. 4720 if (FieldWidth == 1 && Value == 1) 4721 return false; 4722 4723 std::string PrettyValue = Value.toString(10); 4724 std::string PrettyTrunc = TruncatedValue.toString(10); 4725 4726 S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant) 4727 << PrettyValue << PrettyTrunc << OriginalInit->getType() 4728 << Init->getSourceRange(); 4729 4730 return true; 4731} 4732 4733/// Analyze the given simple or compound assignment for warning-worthy 4734/// operations. 4735static void AnalyzeAssignment(Sema &S, BinaryOperator *E) { 4736 // Just recurse on the LHS. 4737 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 4738 4739 // We want to recurse on the RHS as normal unless we're assigning to 4740 // a bitfield. 4741 if (FieldDecl *Bitfield = E->getLHS()->getSourceBitField()) { 4742 if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(), 4743 E->getOperatorLoc())) { 4744 // Recurse, ignoring any implicit conversions on the RHS. 4745 return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(), 4746 E->getOperatorLoc()); 4747 } 4748 } 4749 4750 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 4751} 4752 4753/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 4754static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T, 4755 SourceLocation CContext, unsigned diag, 4756 bool pruneControlFlow = false) { 4757 if (pruneControlFlow) { 4758 S.DiagRuntimeBehavior(E->getExprLoc(), E, 4759 S.PDiag(diag) 4760 << SourceType << T << E->getSourceRange() 4761 << SourceRange(CContext)); 4762 return; 4763 } 4764 S.Diag(E->getExprLoc(), diag) 4765 << SourceType << T << E->getSourceRange() << SourceRange(CContext); 4766} 4767 4768/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 4769static void DiagnoseImpCast(Sema &S, Expr *E, QualType T, 4770 SourceLocation CContext, unsigned diag, 4771 bool pruneControlFlow = false) { 4772 DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow); 4773} 4774 4775/// Diagnose an implicit cast from a literal expression. Does not warn when the 4776/// cast wouldn't lose information. 4777void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T, 4778 SourceLocation CContext) { 4779 // Try to convert the literal exactly to an integer. If we can, don't warn. 4780 bool isExact = false; 4781 const llvm::APFloat &Value = FL->getValue(); 4782 llvm::APSInt IntegerValue(S.Context.getIntWidth(T), 4783 T->hasUnsignedIntegerRepresentation()); 4784 if (Value.convertToInteger(IntegerValue, 4785 llvm::APFloat::rmTowardZero, &isExact) 4786 == llvm::APFloat::opOK && isExact) 4787 return; 4788 4789 SmallString<16> PrettySourceValue; 4790 Value.toString(PrettySourceValue); 4791 SmallString<16> PrettyTargetValue; 4792 if (T->isSpecificBuiltinType(BuiltinType::Bool)) 4793 PrettyTargetValue = IntegerValue == 0 ? "false" : "true"; 4794 else 4795 IntegerValue.toString(PrettyTargetValue); 4796 4797 S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer) 4798 << FL->getType() << T.getUnqualifiedType() << PrettySourceValue 4799 << PrettyTargetValue << FL->getSourceRange() << SourceRange(CContext); 4800} 4801 4802std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) { 4803 if (!Range.Width) return "0"; 4804 4805 llvm::APSInt ValueInRange = Value; 4806 ValueInRange.setIsSigned(!Range.NonNegative); 4807 ValueInRange = ValueInRange.trunc(Range.Width); 4808 return ValueInRange.toString(10); 4809} 4810 4811static bool IsImplicitBoolFloatConversion(Sema &S, Expr *Ex, bool ToBool) { 4812 if (!isa<ImplicitCastExpr>(Ex)) 4813 return false; 4814 4815 Expr *InnerE = Ex->IgnoreParenImpCasts(); 4816 const Type *Target = S.Context.getCanonicalType(Ex->getType()).getTypePtr(); 4817 const Type *Source = 4818 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 4819 if (Target->isDependentType()) 4820 return false; 4821 4822 const BuiltinType *FloatCandidateBT = 4823 dyn_cast<BuiltinType>(ToBool ? Source : Target); 4824 const Type *BoolCandidateType = ToBool ? Target : Source; 4825 4826 return (BoolCandidateType->isSpecificBuiltinType(BuiltinType::Bool) && 4827 FloatCandidateBT && (FloatCandidateBT->isFloatingPoint())); 4828} 4829 4830void CheckImplicitArgumentConversions(Sema &S, CallExpr *TheCall, 4831 SourceLocation CC) { 4832 unsigned NumArgs = TheCall->getNumArgs(); 4833 for (unsigned i = 0; i < NumArgs; ++i) { 4834 Expr *CurrA = TheCall->getArg(i); 4835 if (!IsImplicitBoolFloatConversion(S, CurrA, true)) 4836 continue; 4837 4838 bool IsSwapped = ((i > 0) && 4839 IsImplicitBoolFloatConversion(S, TheCall->getArg(i - 1), false)); 4840 IsSwapped |= ((i < (NumArgs - 1)) && 4841 IsImplicitBoolFloatConversion(S, TheCall->getArg(i + 1), false)); 4842 if (IsSwapped) { 4843 // Warn on this floating-point to bool conversion. 4844 DiagnoseImpCast(S, CurrA->IgnoreParenImpCasts(), 4845 CurrA->getType(), CC, 4846 diag::warn_impcast_floating_point_to_bool); 4847 } 4848 } 4849} 4850 4851void CheckImplicitConversion(Sema &S, Expr *E, QualType T, 4852 SourceLocation CC, bool *ICContext = 0) { 4853 if (E->isTypeDependent() || E->isValueDependent()) return; 4854 4855 const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr(); 4856 const Type *Target = S.Context.getCanonicalType(T).getTypePtr(); 4857 if (Source == Target) return; 4858 if (Target->isDependentType()) return; 4859 4860 // If the conversion context location is invalid don't complain. We also 4861 // don't want to emit a warning if the issue occurs from the expansion of 4862 // a system macro. The problem is that 'getSpellingLoc()' is slow, so we 4863 // delay this check as long as possible. Once we detect we are in that 4864 // scenario, we just return. 4865 if (CC.isInvalid()) 4866 return; 4867 4868 // Diagnose implicit casts to bool. 4869 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) { 4870 if (isa<StringLiteral>(E)) 4871 // Warn on string literal to bool. Checks for string literals in logical 4872 // expressions, for instances, assert(0 && "error here"), is prevented 4873 // by a check in AnalyzeImplicitConversions(). 4874 return DiagnoseImpCast(S, E, T, CC, 4875 diag::warn_impcast_string_literal_to_bool); 4876 if (Source->isFunctionType()) { 4877 // Warn on function to bool. Checks free functions and static member 4878 // functions. Weakly imported functions are excluded from the check, 4879 // since it's common to test their value to check whether the linker 4880 // found a definition for them. 4881 ValueDecl *D = 0; 4882 if (DeclRefExpr* R = dyn_cast<DeclRefExpr>(E)) { 4883 D = R->getDecl(); 4884 } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) { 4885 D = M->getMemberDecl(); 4886 } 4887 4888 if (D && !D->isWeak()) { 4889 if (FunctionDecl* F = dyn_cast<FunctionDecl>(D)) { 4890 S.Diag(E->getExprLoc(), diag::warn_impcast_function_to_bool) 4891 << F << E->getSourceRange() << SourceRange(CC); 4892 S.Diag(E->getExprLoc(), diag::note_function_to_bool_silence) 4893 << FixItHint::CreateInsertion(E->getExprLoc(), "&"); 4894 QualType ReturnType; 4895 UnresolvedSet<4> NonTemplateOverloads; 4896 S.tryExprAsCall(*E, ReturnType, NonTemplateOverloads); 4897 if (!ReturnType.isNull() 4898 && ReturnType->isSpecificBuiltinType(BuiltinType::Bool)) 4899 S.Diag(E->getExprLoc(), diag::note_function_to_bool_call) 4900 << FixItHint::CreateInsertion( 4901 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()), "()"); 4902 return; 4903 } 4904 } 4905 } 4906 } 4907 4908 // Strip vector types. 4909 if (isa<VectorType>(Source)) { 4910 if (!isa<VectorType>(Target)) { 4911 if (S.SourceMgr.isInSystemMacro(CC)) 4912 return; 4913 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar); 4914 } 4915 4916 // If the vector cast is cast between two vectors of the same size, it is 4917 // a bitcast, not a conversion. 4918 if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target)) 4919 return; 4920 4921 Source = cast<VectorType>(Source)->getElementType().getTypePtr(); 4922 Target = cast<VectorType>(Target)->getElementType().getTypePtr(); 4923 } 4924 4925 // Strip complex types. 4926 if (isa<ComplexType>(Source)) { 4927 if (!isa<ComplexType>(Target)) { 4928 if (S.SourceMgr.isInSystemMacro(CC)) 4929 return; 4930 4931 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar); 4932 } 4933 4934 Source = cast<ComplexType>(Source)->getElementType().getTypePtr(); 4935 Target = cast<ComplexType>(Target)->getElementType().getTypePtr(); 4936 } 4937 4938 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source); 4939 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target); 4940 4941 // If the source is floating point... 4942 if (SourceBT && SourceBT->isFloatingPoint()) { 4943 // ...and the target is floating point... 4944 if (TargetBT && TargetBT->isFloatingPoint()) { 4945 // ...then warn if we're dropping FP rank. 4946 4947 // Builtin FP kinds are ordered by increasing FP rank. 4948 if (SourceBT->getKind() > TargetBT->getKind()) { 4949 // Don't warn about float constants that are precisely 4950 // representable in the target type. 4951 Expr::EvalResult result; 4952 if (E->EvaluateAsRValue(result, S.Context)) { 4953 // Value might be a float, a float vector, or a float complex. 4954 if (IsSameFloatAfterCast(result.Val, 4955 S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)), 4956 S.Context.getFloatTypeSemantics(QualType(SourceBT, 0)))) 4957 return; 4958 } 4959 4960 if (S.SourceMgr.isInSystemMacro(CC)) 4961 return; 4962 4963 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision); 4964 } 4965 return; 4966 } 4967 4968 // If the target is integral, always warn. 4969 if (TargetBT && TargetBT->isInteger()) { 4970 if (S.SourceMgr.isInSystemMacro(CC)) 4971 return; 4972 4973 Expr *InnerE = E->IgnoreParenImpCasts(); 4974 // We also want to warn on, e.g., "int i = -1.234" 4975 if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE)) 4976 if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus) 4977 InnerE = UOp->getSubExpr()->IgnoreParenImpCasts(); 4978 4979 if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) { 4980 DiagnoseFloatingLiteralImpCast(S, FL, T, CC); 4981 } else { 4982 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer); 4983 } 4984 } 4985 4986 // If the target is bool, warn if expr is a function or method call. 4987 if (Target->isSpecificBuiltinType(BuiltinType::Bool) && 4988 isa<CallExpr>(E)) { 4989 // Check last argument of function call to see if it is an 4990 // implicit cast from a type matching the type the result 4991 // is being cast to. 4992 CallExpr *CEx = cast<CallExpr>(E); 4993 unsigned NumArgs = CEx->getNumArgs(); 4994 if (NumArgs > 0) { 4995 Expr *LastA = CEx->getArg(NumArgs - 1); 4996 Expr *InnerE = LastA->IgnoreParenImpCasts(); 4997 const Type *InnerType = 4998 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 4999 if (isa<ImplicitCastExpr>(LastA) && (InnerType == Target)) { 5000 // Warn on this floating-point to bool conversion 5001 DiagnoseImpCast(S, E, T, CC, 5002 diag::warn_impcast_floating_point_to_bool); 5003 } 5004 } 5005 } 5006 return; 5007 } 5008 5009 if ((E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull) 5010 == Expr::NPCK_GNUNull) && !Target->isAnyPointerType() 5011 && !Target->isBlockPointerType() && !Target->isMemberPointerType() 5012 && Target->isScalarType() && !Target->isNullPtrType()) { 5013 SourceLocation Loc = E->getSourceRange().getBegin(); 5014 if (Loc.isMacroID()) 5015 Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first; 5016 if (!Loc.isMacroID() || CC.isMacroID()) 5017 S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer) 5018 << T << clang::SourceRange(CC) 5019 << FixItHint::CreateReplacement(Loc, S.getFixItZeroLiteralForType(T)); 5020 } 5021 5022 if (!Source->isIntegerType() || !Target->isIntegerType()) 5023 return; 5024 5025 // TODO: remove this early return once the false positives for constant->bool 5026 // in templates, macros, etc, are reduced or removed. 5027 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) 5028 return; 5029 5030 IntRange SourceRange = GetExprRange(S.Context, E); 5031 IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target); 5032 5033 if (SourceRange.Width > TargetRange.Width) { 5034 // If the source is a constant, use a default-on diagnostic. 5035 // TODO: this should happen for bitfield stores, too. 5036 llvm::APSInt Value(32); 5037 if (E->isIntegerConstantExpr(Value, S.Context)) { 5038 if (S.SourceMgr.isInSystemMacro(CC)) 5039 return; 5040 5041 std::string PrettySourceValue = Value.toString(10); 5042 std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange); 5043 5044 S.DiagRuntimeBehavior(E->getExprLoc(), E, 5045 S.PDiag(diag::warn_impcast_integer_precision_constant) 5046 << PrettySourceValue << PrettyTargetValue 5047 << E->getType() << T << E->getSourceRange() 5048 << clang::SourceRange(CC)); 5049 return; 5050 } 5051 5052 // People want to build with -Wshorten-64-to-32 and not -Wconversion. 5053 if (S.SourceMgr.isInSystemMacro(CC)) 5054 return; 5055 5056 if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64) 5057 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32, 5058 /* pruneControlFlow */ true); 5059 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision); 5060 } 5061 5062 if ((TargetRange.NonNegative && !SourceRange.NonNegative) || 5063 (!TargetRange.NonNegative && SourceRange.NonNegative && 5064 SourceRange.Width == TargetRange.Width)) { 5065 5066 if (S.SourceMgr.isInSystemMacro(CC)) 5067 return; 5068 5069 unsigned DiagID = diag::warn_impcast_integer_sign; 5070 5071 // Traditionally, gcc has warned about this under -Wsign-compare. 5072 // We also want to warn about it in -Wconversion. 5073 // So if -Wconversion is off, use a completely identical diagnostic 5074 // in the sign-compare group. 5075 // The conditional-checking code will 5076 if (ICContext) { 5077 DiagID = diag::warn_impcast_integer_sign_conditional; 5078 *ICContext = true; 5079 } 5080 5081 return DiagnoseImpCast(S, E, T, CC, DiagID); 5082 } 5083 5084 // Diagnose conversions between different enumeration types. 5085 // In C, we pretend that the type of an EnumConstantDecl is its enumeration 5086 // type, to give us better diagnostics. 5087 QualType SourceType = E->getType(); 5088 if (!S.getLangOpts().CPlusPlus) { 5089 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 5090 if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) { 5091 EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext()); 5092 SourceType = S.Context.getTypeDeclType(Enum); 5093 Source = S.Context.getCanonicalType(SourceType).getTypePtr(); 5094 } 5095 } 5096 5097 if (const EnumType *SourceEnum = Source->getAs<EnumType>()) 5098 if (const EnumType *TargetEnum = Target->getAs<EnumType>()) 5099 if (SourceEnum->getDecl()->hasNameForLinkage() && 5100 TargetEnum->getDecl()->hasNameForLinkage() && 5101 SourceEnum != TargetEnum) { 5102 if (S.SourceMgr.isInSystemMacro(CC)) 5103 return; 5104 5105 return DiagnoseImpCast(S, E, SourceType, T, CC, 5106 diag::warn_impcast_different_enum_types); 5107 } 5108 5109 return; 5110} 5111 5112void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 5113 SourceLocation CC, QualType T); 5114 5115void CheckConditionalOperand(Sema &S, Expr *E, QualType T, 5116 SourceLocation CC, bool &ICContext) { 5117 E = E->IgnoreParenImpCasts(); 5118 5119 if (isa<ConditionalOperator>(E)) 5120 return CheckConditionalOperator(S, cast<ConditionalOperator>(E), CC, T); 5121 5122 AnalyzeImplicitConversions(S, E, CC); 5123 if (E->getType() != T) 5124 return CheckImplicitConversion(S, E, T, CC, &ICContext); 5125 return; 5126} 5127 5128void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 5129 SourceLocation CC, QualType T) { 5130 AnalyzeImplicitConversions(S, E->getCond(), CC); 5131 5132 bool Suspicious = false; 5133 CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious); 5134 CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious); 5135 5136 // If -Wconversion would have warned about either of the candidates 5137 // for a signedness conversion to the context type... 5138 if (!Suspicious) return; 5139 5140 // ...but it's currently ignored... 5141 if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional, 5142 CC)) 5143 return; 5144 5145 // ...then check whether it would have warned about either of the 5146 // candidates for a signedness conversion to the condition type. 5147 if (E->getType() == T) return; 5148 5149 Suspicious = false; 5150 CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(), 5151 E->getType(), CC, &Suspicious); 5152 if (!Suspicious) 5153 CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(), 5154 E->getType(), CC, &Suspicious); 5155} 5156 5157/// AnalyzeImplicitConversions - Find and report any interesting 5158/// implicit conversions in the given expression. There are a couple 5159/// of competing diagnostics here, -Wconversion and -Wsign-compare. 5160void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) { 5161 QualType T = OrigE->getType(); 5162 Expr *E = OrigE->IgnoreParenImpCasts(); 5163 5164 if (E->isTypeDependent() || E->isValueDependent()) 5165 return; 5166 5167 // For conditional operators, we analyze the arguments as if they 5168 // were being fed directly into the output. 5169 if (isa<ConditionalOperator>(E)) { 5170 ConditionalOperator *CO = cast<ConditionalOperator>(E); 5171 CheckConditionalOperator(S, CO, CC, T); 5172 return; 5173 } 5174 5175 // Check implicit argument conversions for function calls. 5176 if (CallExpr *Call = dyn_cast<CallExpr>(E)) 5177 CheckImplicitArgumentConversions(S, Call, CC); 5178 5179 // Go ahead and check any implicit conversions we might have skipped. 5180 // The non-canonical typecheck is just an optimization; 5181 // CheckImplicitConversion will filter out dead implicit conversions. 5182 if (E->getType() != T) 5183 CheckImplicitConversion(S, E, T, CC); 5184 5185 // Now continue drilling into this expression. 5186 5187 if (PseudoObjectExpr * POE = dyn_cast<PseudoObjectExpr>(E)) { 5188 if (POE->getResultExpr()) 5189 E = POE->getResultExpr(); 5190 } 5191 5192 if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) 5193 return AnalyzeImplicitConversions(S, OVE->getSourceExpr(), CC); 5194 5195 // Skip past explicit casts. 5196 if (isa<ExplicitCastExpr>(E)) { 5197 E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts(); 5198 return AnalyzeImplicitConversions(S, E, CC); 5199 } 5200 5201 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 5202 // Do a somewhat different check with comparison operators. 5203 if (BO->isComparisonOp()) 5204 return AnalyzeComparison(S, BO); 5205 5206 // And with simple assignments. 5207 if (BO->getOpcode() == BO_Assign) 5208 return AnalyzeAssignment(S, BO); 5209 } 5210 5211 // These break the otherwise-useful invariant below. Fortunately, 5212 // we don't really need to recurse into them, because any internal 5213 // expressions should have been analyzed already when they were 5214 // built into statements. 5215 if (isa<StmtExpr>(E)) return; 5216 5217 // Don't descend into unevaluated contexts. 5218 if (isa<UnaryExprOrTypeTraitExpr>(E)) return; 5219 5220 // Now just recurse over the expression's children. 5221 CC = E->getExprLoc(); 5222 BinaryOperator *BO = dyn_cast<BinaryOperator>(E); 5223 bool IsLogicalOperator = BO && BO->isLogicalOp(); 5224 for (Stmt::child_range I = E->children(); I; ++I) { 5225 Expr *ChildExpr = dyn_cast_or_null<Expr>(*I); 5226 if (!ChildExpr) 5227 continue; 5228 5229 if (IsLogicalOperator && 5230 isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts())) 5231 // Ignore checking string literals that are in logical operators. 5232 continue; 5233 AnalyzeImplicitConversions(S, ChildExpr, CC); 5234 } 5235} 5236 5237} // end anonymous namespace 5238 5239/// Diagnoses "dangerous" implicit conversions within the given 5240/// expression (which is a full expression). Implements -Wconversion 5241/// and -Wsign-compare. 5242/// 5243/// \param CC the "context" location of the implicit conversion, i.e. 5244/// the most location of the syntactic entity requiring the implicit 5245/// conversion 5246void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) { 5247 // Don't diagnose in unevaluated contexts. 5248 if (isUnevaluatedContext()) 5249 return; 5250 5251 // Don't diagnose for value- or type-dependent expressions. 5252 if (E->isTypeDependent() || E->isValueDependent()) 5253 return; 5254 5255 // Check for array bounds violations in cases where the check isn't triggered 5256 // elsewhere for other Expr types (like BinaryOperators), e.g. when an 5257 // ArraySubscriptExpr is on the RHS of a variable initialization. 5258 CheckArrayAccess(E); 5259 5260 // This is not the right CC for (e.g.) a variable initialization. 5261 AnalyzeImplicitConversions(*this, E, CC); 5262} 5263 5264/// Diagnose when expression is an integer constant expression and its evaluation 5265/// results in integer overflow 5266void Sema::CheckForIntOverflow (Expr *E) { 5267 if (isa<BinaryOperator>(E->IgnoreParens())) { 5268 llvm::SmallVector<PartialDiagnosticAt, 4> Diags; 5269 E->EvaluateForOverflow(Context, &Diags); 5270 } 5271} 5272 5273namespace { 5274/// \brief Visitor for expressions which looks for unsequenced operations on the 5275/// same object. 5276class SequenceChecker : public EvaluatedExprVisitor<SequenceChecker> { 5277 /// \brief A tree of sequenced regions within an expression. Two regions are 5278 /// unsequenced if one is an ancestor or a descendent of the other. When we 5279 /// finish processing an expression with sequencing, such as a comma 5280 /// expression, we fold its tree nodes into its parent, since they are 5281 /// unsequenced with respect to nodes we will visit later. 5282 class SequenceTree { 5283 struct Value { 5284 explicit Value(unsigned Parent) : Parent(Parent), Merged(false) {} 5285 unsigned Parent : 31; 5286 bool Merged : 1; 5287 }; 5288 llvm::SmallVector<Value, 8> Values; 5289 5290 public: 5291 /// \brief A region within an expression which may be sequenced with respect 5292 /// to some other region. 5293 class Seq { 5294 explicit Seq(unsigned N) : Index(N) {} 5295 unsigned Index; 5296 friend class SequenceTree; 5297 public: 5298 Seq() : Index(0) {} 5299 }; 5300 5301 SequenceTree() { Values.push_back(Value(0)); } 5302 Seq root() const { return Seq(0); } 5303 5304 /// \brief Create a new sequence of operations, which is an unsequenced 5305 /// subset of \p Parent. This sequence of operations is sequenced with 5306 /// respect to other children of \p Parent. 5307 Seq allocate(Seq Parent) { 5308 Values.push_back(Value(Parent.Index)); 5309 return Seq(Values.size() - 1); 5310 } 5311 5312 /// \brief Merge a sequence of operations into its parent. 5313 void merge(Seq S) { 5314 Values[S.Index].Merged = true; 5315 } 5316 5317 /// \brief Determine whether two operations are unsequenced. This operation 5318 /// is asymmetric: \p Cur should be the more recent sequence, and \p Old 5319 /// should have been merged into its parent as appropriate. 5320 bool isUnsequenced(Seq Cur, Seq Old) { 5321 unsigned C = representative(Cur.Index); 5322 unsigned Target = representative(Old.Index); 5323 while (C >= Target) { 5324 if (C == Target) 5325 return true; 5326 C = Values[C].Parent; 5327 } 5328 return false; 5329 } 5330 5331 private: 5332 /// \brief Pick a representative for a sequence. 5333 unsigned representative(unsigned K) { 5334 if (Values[K].Merged) 5335 // Perform path compression as we go. 5336 return Values[K].Parent = representative(Values[K].Parent); 5337 return K; 5338 } 5339 }; 5340 5341 /// An object for which we can track unsequenced uses. 5342 typedef NamedDecl *Object; 5343 5344 /// Different flavors of object usage which we track. We only track the 5345 /// least-sequenced usage of each kind. 5346 enum UsageKind { 5347 /// A read of an object. Multiple unsequenced reads are OK. 5348 UK_Use, 5349 /// A modification of an object which is sequenced before the value 5350 /// computation of the expression, such as ++n. 5351 UK_ModAsValue, 5352 /// A modification of an object which is not sequenced before the value 5353 /// computation of the expression, such as n++. 5354 UK_ModAsSideEffect, 5355 5356 UK_Count = UK_ModAsSideEffect + 1 5357 }; 5358 5359 struct Usage { 5360 Usage() : Use(0), Seq() {} 5361 Expr *Use; 5362 SequenceTree::Seq Seq; 5363 }; 5364 5365 struct UsageInfo { 5366 UsageInfo() : Diagnosed(false) {} 5367 Usage Uses[UK_Count]; 5368 /// Have we issued a diagnostic for this variable already? 5369 bool Diagnosed; 5370 }; 5371 typedef llvm::SmallDenseMap<Object, UsageInfo, 16> UsageInfoMap; 5372 5373 Sema &SemaRef; 5374 /// Sequenced regions within the expression. 5375 SequenceTree Tree; 5376 /// Declaration modifications and references which we have seen. 5377 UsageInfoMap UsageMap; 5378 /// The region we are currently within. 5379 SequenceTree::Seq Region; 5380 /// Filled in with declarations which were modified as a side-effect 5381 /// (that is, post-increment operations). 5382 llvm::SmallVectorImpl<std::pair<Object, Usage> > *ModAsSideEffect; 5383 /// Expressions to check later. We defer checking these to reduce 5384 /// stack usage. 5385 llvm::SmallVectorImpl<Expr*> &WorkList; 5386 5387 /// RAII object wrapping the visitation of a sequenced subexpression of an 5388 /// expression. At the end of this process, the side-effects of the evaluation 5389 /// become sequenced with respect to the value computation of the result, so 5390 /// we downgrade any UK_ModAsSideEffect within the evaluation to 5391 /// UK_ModAsValue. 5392 struct SequencedSubexpression { 5393 SequencedSubexpression(SequenceChecker &Self) 5394 : Self(Self), OldModAsSideEffect(Self.ModAsSideEffect) { 5395 Self.ModAsSideEffect = &ModAsSideEffect; 5396 } 5397 ~SequencedSubexpression() { 5398 for (unsigned I = 0, E = ModAsSideEffect.size(); I != E; ++I) { 5399 UsageInfo &U = Self.UsageMap[ModAsSideEffect[I].first]; 5400 U.Uses[UK_ModAsSideEffect] = ModAsSideEffect[I].second; 5401 Self.addUsage(U, ModAsSideEffect[I].first, 5402 ModAsSideEffect[I].second.Use, UK_ModAsValue); 5403 } 5404 Self.ModAsSideEffect = OldModAsSideEffect; 5405 } 5406 5407 SequenceChecker &Self; 5408 llvm::SmallVector<std::pair<Object, Usage>, 4> ModAsSideEffect; 5409 llvm::SmallVectorImpl<std::pair<Object, Usage> > *OldModAsSideEffect; 5410 }; 5411 5412 /// RAII object wrapping the visitation of a subexpression which we might 5413 /// choose to evaluate as a constant. If any subexpression is evaluated and 5414 /// found to be non-constant, this allows us to suppress the evaluation of 5415 /// the outer expression. 5416 class EvaluationTracker { 5417 public: 5418 EvaluationTracker(SequenceChecker &Self) 5419 : Self(Self), Prev(Self.EvalTracker), EvalOK(true) { 5420 Self.EvalTracker = this; 5421 } 5422 ~EvaluationTracker() { 5423 Self.EvalTracker = Prev; 5424 if (Prev) 5425 Prev->EvalOK &= EvalOK; 5426 } 5427 5428 bool evaluate(const Expr *E, bool &Result) { 5429 if (!EvalOK || E->isValueDependent()) 5430 return false; 5431 EvalOK = E->EvaluateAsBooleanCondition(Result, Self.SemaRef.Context); 5432 return EvalOK; 5433 } 5434 5435 private: 5436 SequenceChecker &Self; 5437 EvaluationTracker *Prev; 5438 bool EvalOK; 5439 } *EvalTracker; 5440 5441 /// \brief Find the object which is produced by the specified expression, 5442 /// if any. 5443 Object getObject(Expr *E, bool Mod) const { 5444 E = E->IgnoreParenCasts(); 5445 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 5446 if (Mod && (UO->getOpcode() == UO_PreInc || UO->getOpcode() == UO_PreDec)) 5447 return getObject(UO->getSubExpr(), Mod); 5448 } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 5449 if (BO->getOpcode() == BO_Comma) 5450 return getObject(BO->getRHS(), Mod); 5451 if (Mod && BO->isAssignmentOp()) 5452 return getObject(BO->getLHS(), Mod); 5453 } else if (MemberExpr *ME = dyn_cast<MemberExpr>(E)) { 5454 // FIXME: Check for more interesting cases, like "x.n = ++x.n". 5455 if (isa<CXXThisExpr>(ME->getBase()->IgnoreParenCasts())) 5456 return ME->getMemberDecl(); 5457 } else if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 5458 // FIXME: If this is a reference, map through to its value. 5459 return DRE->getDecl(); 5460 return 0; 5461 } 5462 5463 /// \brief Note that an object was modified or used by an expression. 5464 void addUsage(UsageInfo &UI, Object O, Expr *Ref, UsageKind UK) { 5465 Usage &U = UI.Uses[UK]; 5466 if (!U.Use || !Tree.isUnsequenced(Region, U.Seq)) { 5467 if (UK == UK_ModAsSideEffect && ModAsSideEffect) 5468 ModAsSideEffect->push_back(std::make_pair(O, U)); 5469 U.Use = Ref; 5470 U.Seq = Region; 5471 } 5472 } 5473 /// \brief Check whether a modification or use conflicts with a prior usage. 5474 void checkUsage(Object O, UsageInfo &UI, Expr *Ref, UsageKind OtherKind, 5475 bool IsModMod) { 5476 if (UI.Diagnosed) 5477 return; 5478 5479 const Usage &U = UI.Uses[OtherKind]; 5480 if (!U.Use || !Tree.isUnsequenced(Region, U.Seq)) 5481 return; 5482 5483 Expr *Mod = U.Use; 5484 Expr *ModOrUse = Ref; 5485 if (OtherKind == UK_Use) 5486 std::swap(Mod, ModOrUse); 5487 5488 SemaRef.Diag(Mod->getExprLoc(), 5489 IsModMod ? diag::warn_unsequenced_mod_mod 5490 : diag::warn_unsequenced_mod_use) 5491 << O << SourceRange(ModOrUse->getExprLoc()); 5492 UI.Diagnosed = true; 5493 } 5494 5495 void notePreUse(Object O, Expr *Use) { 5496 UsageInfo &U = UsageMap[O]; 5497 // Uses conflict with other modifications. 5498 checkUsage(O, U, Use, UK_ModAsValue, false); 5499 } 5500 void notePostUse(Object O, Expr *Use) { 5501 UsageInfo &U = UsageMap[O]; 5502 checkUsage(O, U, Use, UK_ModAsSideEffect, false); 5503 addUsage(U, O, Use, UK_Use); 5504 } 5505 5506 void notePreMod(Object O, Expr *Mod) { 5507 UsageInfo &U = UsageMap[O]; 5508 // Modifications conflict with other modifications and with uses. 5509 checkUsage(O, U, Mod, UK_ModAsValue, true); 5510 checkUsage(O, U, Mod, UK_Use, false); 5511 } 5512 void notePostMod(Object O, Expr *Use, UsageKind UK) { 5513 UsageInfo &U = UsageMap[O]; 5514 checkUsage(O, U, Use, UK_ModAsSideEffect, true); 5515 addUsage(U, O, Use, UK); 5516 } 5517 5518public: 5519 SequenceChecker(Sema &S, Expr *E, 5520 llvm::SmallVectorImpl<Expr*> &WorkList) 5521 : EvaluatedExprVisitor<SequenceChecker>(S.Context), SemaRef(S), 5522 Region(Tree.root()), ModAsSideEffect(0), WorkList(WorkList), 5523 EvalTracker(0) { 5524 Visit(E); 5525 } 5526 5527 void VisitStmt(Stmt *S) { 5528 // Skip all statements which aren't expressions for now. 5529 } 5530 5531 void VisitExpr(Expr *E) { 5532 // By default, just recurse to evaluated subexpressions. 5533 EvaluatedExprVisitor<SequenceChecker>::VisitStmt(E); 5534 } 5535 5536 void VisitCastExpr(CastExpr *E) { 5537 Object O = Object(); 5538 if (E->getCastKind() == CK_LValueToRValue) 5539 O = getObject(E->getSubExpr(), false); 5540 5541 if (O) 5542 notePreUse(O, E); 5543 VisitExpr(E); 5544 if (O) 5545 notePostUse(O, E); 5546 } 5547 5548 void VisitBinComma(BinaryOperator *BO) { 5549 // C++11 [expr.comma]p1: 5550 // Every value computation and side effect associated with the left 5551 // expression is sequenced before every value computation and side 5552 // effect associated with the right expression. 5553 SequenceTree::Seq LHS = Tree.allocate(Region); 5554 SequenceTree::Seq RHS = Tree.allocate(Region); 5555 SequenceTree::Seq OldRegion = Region; 5556 5557 { 5558 SequencedSubexpression SeqLHS(*this); 5559 Region = LHS; 5560 Visit(BO->getLHS()); 5561 } 5562 5563 Region = RHS; 5564 Visit(BO->getRHS()); 5565 5566 Region = OldRegion; 5567 5568 // Forget that LHS and RHS are sequenced. They are both unsequenced 5569 // with respect to other stuff. 5570 Tree.merge(LHS); 5571 Tree.merge(RHS); 5572 } 5573 5574 void VisitBinAssign(BinaryOperator *BO) { 5575 // The modification is sequenced after the value computation of the LHS 5576 // and RHS, so check it before inspecting the operands and update the 5577 // map afterwards. 5578 Object O = getObject(BO->getLHS(), true); 5579 if (!O) 5580 return VisitExpr(BO); 5581 5582 notePreMod(O, BO); 5583 5584 // C++11 [expr.ass]p7: 5585 // E1 op= E2 is equivalent to E1 = E1 op E2, except that E1 is evaluated 5586 // only once. 5587 // 5588 // Therefore, for a compound assignment operator, O is considered used 5589 // everywhere except within the evaluation of E1 itself. 5590 if (isa<CompoundAssignOperator>(BO)) 5591 notePreUse(O, BO); 5592 5593 Visit(BO->getLHS()); 5594 5595 if (isa<CompoundAssignOperator>(BO)) 5596 notePostUse(O, BO); 5597 5598 Visit(BO->getRHS()); 5599 5600 notePostMod(O, BO, UK_ModAsValue); 5601 } 5602 void VisitCompoundAssignOperator(CompoundAssignOperator *CAO) { 5603 VisitBinAssign(CAO); 5604 } 5605 5606 void VisitUnaryPreInc(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); } 5607 void VisitUnaryPreDec(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); } 5608 void VisitUnaryPreIncDec(UnaryOperator *UO) { 5609 Object O = getObject(UO->getSubExpr(), true); 5610 if (!O) 5611 return VisitExpr(UO); 5612 5613 notePreMod(O, UO); 5614 Visit(UO->getSubExpr()); 5615 notePostMod(O, UO, UK_ModAsValue); 5616 } 5617 5618 void VisitUnaryPostInc(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); } 5619 void VisitUnaryPostDec(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); } 5620 void VisitUnaryPostIncDec(UnaryOperator *UO) { 5621 Object O = getObject(UO->getSubExpr(), true); 5622 if (!O) 5623 return VisitExpr(UO); 5624 5625 notePreMod(O, UO); 5626 Visit(UO->getSubExpr()); 5627 notePostMod(O, UO, UK_ModAsSideEffect); 5628 } 5629 5630 /// Don't visit the RHS of '&&' or '||' if it might not be evaluated. 5631 void VisitBinLOr(BinaryOperator *BO) { 5632 // The side-effects of the LHS of an '&&' are sequenced before the 5633 // value computation of the RHS, and hence before the value computation 5634 // of the '&&' itself, unless the LHS evaluates to zero. We treat them 5635 // as if they were unconditionally sequenced. 5636 EvaluationTracker Eval(*this); 5637 { 5638 SequencedSubexpression Sequenced(*this); 5639 Visit(BO->getLHS()); 5640 } 5641 5642 bool Result; 5643 if (Eval.evaluate(BO->getLHS(), Result)) { 5644 if (!Result) 5645 Visit(BO->getRHS()); 5646 } else { 5647 // Check for unsequenced operations in the RHS, treating it as an 5648 // entirely separate evaluation. 5649 // 5650 // FIXME: If there are operations in the RHS which are unsequenced 5651 // with respect to operations outside the RHS, and those operations 5652 // are unconditionally evaluated, diagnose them. 5653 WorkList.push_back(BO->getRHS()); 5654 } 5655 } 5656 void VisitBinLAnd(BinaryOperator *BO) { 5657 EvaluationTracker Eval(*this); 5658 { 5659 SequencedSubexpression Sequenced(*this); 5660 Visit(BO->getLHS()); 5661 } 5662 5663 bool Result; 5664 if (Eval.evaluate(BO->getLHS(), Result)) { 5665 if (Result) 5666 Visit(BO->getRHS()); 5667 } else { 5668 WorkList.push_back(BO->getRHS()); 5669 } 5670 } 5671 5672 // Only visit the condition, unless we can be sure which subexpression will 5673 // be chosen. 5674 void VisitAbstractConditionalOperator(AbstractConditionalOperator *CO) { 5675 EvaluationTracker Eval(*this); 5676 SequencedSubexpression Sequenced(*this); 5677 Visit(CO->getCond()); 5678 5679 bool Result; 5680 if (Eval.evaluate(CO->getCond(), Result)) 5681 Visit(Result ? CO->getTrueExpr() : CO->getFalseExpr()); 5682 else { 5683 WorkList.push_back(CO->getTrueExpr()); 5684 WorkList.push_back(CO->getFalseExpr()); 5685 } 5686 } 5687 5688 void VisitCXXConstructExpr(CXXConstructExpr *CCE) { 5689 if (!CCE->isListInitialization()) 5690 return VisitExpr(CCE); 5691 5692 // In C++11, list initializations are sequenced. 5693 llvm::SmallVector<SequenceTree::Seq, 32> Elts; 5694 SequenceTree::Seq Parent = Region; 5695 for (CXXConstructExpr::arg_iterator I = CCE->arg_begin(), 5696 E = CCE->arg_end(); 5697 I != E; ++I) { 5698 Region = Tree.allocate(Parent); 5699 Elts.push_back(Region); 5700 Visit(*I); 5701 } 5702 5703 // Forget that the initializers are sequenced. 5704 Region = Parent; 5705 for (unsigned I = 0; I < Elts.size(); ++I) 5706 Tree.merge(Elts[I]); 5707 } 5708 5709 void VisitInitListExpr(InitListExpr *ILE) { 5710 if (!SemaRef.getLangOpts().CPlusPlus11) 5711 return VisitExpr(ILE); 5712 5713 // In C++11, list initializations are sequenced. 5714 llvm::SmallVector<SequenceTree::Seq, 32> Elts; 5715 SequenceTree::Seq Parent = Region; 5716 for (unsigned I = 0; I < ILE->getNumInits(); ++I) { 5717 Expr *E = ILE->getInit(I); 5718 if (!E) continue; 5719 Region = Tree.allocate(Parent); 5720 Elts.push_back(Region); 5721 Visit(E); 5722 } 5723 5724 // Forget that the initializers are sequenced. 5725 Region = Parent; 5726 for (unsigned I = 0; I < Elts.size(); ++I) 5727 Tree.merge(Elts[I]); 5728 } 5729}; 5730} 5731 5732void Sema::CheckUnsequencedOperations(Expr *E) { 5733 llvm::SmallVector<Expr*, 8> WorkList; 5734 WorkList.push_back(E); 5735 while (!WorkList.empty()) { 5736 Expr *Item = WorkList.back(); 5737 WorkList.pop_back(); 5738 SequenceChecker(*this, Item, WorkList); 5739 } 5740} 5741 5742void Sema::CheckCompletedExpr(Expr *E, SourceLocation CheckLoc, 5743 bool IsConstexpr) { 5744 CheckImplicitConversions(E, CheckLoc); 5745 CheckUnsequencedOperations(E); 5746 if (!IsConstexpr && !E->isValueDependent()) 5747 CheckForIntOverflow(E); 5748} 5749 5750void Sema::CheckBitFieldInitialization(SourceLocation InitLoc, 5751 FieldDecl *BitField, 5752 Expr *Init) { 5753 (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc); 5754} 5755 5756/// CheckParmsForFunctionDef - Check that the parameters of the given 5757/// function are appropriate for the definition of a function. This 5758/// takes care of any checks that cannot be performed on the 5759/// declaration itself, e.g., that the types of each of the function 5760/// parameters are complete. 5761bool Sema::CheckParmsForFunctionDef(ParmVarDecl **P, ParmVarDecl **PEnd, 5762 bool CheckParameterNames) { 5763 bool HasInvalidParm = false; 5764 for (; P != PEnd; ++P) { 5765 ParmVarDecl *Param = *P; 5766 5767 // C99 6.7.5.3p4: the parameters in a parameter type list in a 5768 // function declarator that is part of a function definition of 5769 // that function shall not have incomplete type. 5770 // 5771 // This is also C++ [dcl.fct]p6. 5772 if (!Param->isInvalidDecl() && 5773 RequireCompleteType(Param->getLocation(), Param->getType(), 5774 diag::err_typecheck_decl_incomplete_type)) { 5775 Param->setInvalidDecl(); 5776 HasInvalidParm = true; 5777 } 5778 5779 // C99 6.9.1p5: If the declarator includes a parameter type list, the 5780 // declaration of each parameter shall include an identifier. 5781 if (CheckParameterNames && 5782 Param->getIdentifier() == 0 && 5783 !Param->isImplicit() && 5784 !getLangOpts().CPlusPlus) 5785 Diag(Param->getLocation(), diag::err_parameter_name_omitted); 5786 5787 // C99 6.7.5.3p12: 5788 // If the function declarator is not part of a definition of that 5789 // function, parameters may have incomplete type and may use the [*] 5790 // notation in their sequences of declarator specifiers to specify 5791 // variable length array types. 5792 QualType PType = Param->getOriginalType(); 5793 while (const ArrayType *AT = Context.getAsArrayType(PType)) { 5794 if (AT->getSizeModifier() == ArrayType::Star) { 5795 // FIXME: This diagnostic should point the '[*]' if source-location 5796 // information is added for it. 5797 Diag(Param->getLocation(), diag::err_array_star_in_function_definition); 5798 break; 5799 } 5800 PType= AT->getElementType(); 5801 } 5802 5803 // MSVC destroys objects passed by value in the callee. Therefore a 5804 // function definition which takes such a parameter must be able to call the 5805 // object's destructor. 5806 if (getLangOpts().CPlusPlus && 5807 Context.getTargetInfo().getCXXABI().isArgumentDestroyedByCallee()) { 5808 if (const RecordType *RT = Param->getType()->getAs<RecordType>()) 5809 FinalizeVarWithDestructor(Param, RT); 5810 } 5811 } 5812 5813 return HasInvalidParm; 5814} 5815 5816/// CheckCastAlign - Implements -Wcast-align, which warns when a 5817/// pointer cast increases the alignment requirements. 5818void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) { 5819 // This is actually a lot of work to potentially be doing on every 5820 // cast; don't do it if we're ignoring -Wcast_align (as is the default). 5821 if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align, 5822 TRange.getBegin()) 5823 == DiagnosticsEngine::Ignored) 5824 return; 5825 5826 // Ignore dependent types. 5827 if (T->isDependentType() || Op->getType()->isDependentType()) 5828 return; 5829 5830 // Require that the destination be a pointer type. 5831 const PointerType *DestPtr = T->getAs<PointerType>(); 5832 if (!DestPtr) return; 5833 5834 // If the destination has alignment 1, we're done. 5835 QualType DestPointee = DestPtr->getPointeeType(); 5836 if (DestPointee->isIncompleteType()) return; 5837 CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee); 5838 if (DestAlign.isOne()) return; 5839 5840 // Require that the source be a pointer type. 5841 const PointerType *SrcPtr = Op->getType()->getAs<PointerType>(); 5842 if (!SrcPtr) return; 5843 QualType SrcPointee = SrcPtr->getPointeeType(); 5844 5845 // Whitelist casts from cv void*. We already implicitly 5846 // whitelisted casts to cv void*, since they have alignment 1. 5847 // Also whitelist casts involving incomplete types, which implicitly 5848 // includes 'void'. 5849 if (SrcPointee->isIncompleteType()) return; 5850 5851 CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee); 5852 if (SrcAlign >= DestAlign) return; 5853 5854 Diag(TRange.getBegin(), diag::warn_cast_align) 5855 << Op->getType() << T 5856 << static_cast<unsigned>(SrcAlign.getQuantity()) 5857 << static_cast<unsigned>(DestAlign.getQuantity()) 5858 << TRange << Op->getSourceRange(); 5859} 5860 5861static const Type* getElementType(const Expr *BaseExpr) { 5862 const Type* EltType = BaseExpr->getType().getTypePtr(); 5863 if (EltType->isAnyPointerType()) 5864 return EltType->getPointeeType().getTypePtr(); 5865 else if (EltType->isArrayType()) 5866 return EltType->getBaseElementTypeUnsafe(); 5867 return EltType; 5868} 5869 5870/// \brief Check whether this array fits the idiom of a size-one tail padded 5871/// array member of a struct. 5872/// 5873/// We avoid emitting out-of-bounds access warnings for such arrays as they are 5874/// commonly used to emulate flexible arrays in C89 code. 5875static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size, 5876 const NamedDecl *ND) { 5877 if (Size != 1 || !ND) return false; 5878 5879 const FieldDecl *FD = dyn_cast<FieldDecl>(ND); 5880 if (!FD) return false; 5881 5882 // Don't consider sizes resulting from macro expansions or template argument 5883 // substitution to form C89 tail-padded arrays. 5884 5885 TypeSourceInfo *TInfo = FD->getTypeSourceInfo(); 5886 while (TInfo) { 5887 TypeLoc TL = TInfo->getTypeLoc(); 5888 // Look through typedefs. 5889 if (TypedefTypeLoc TTL = TL.getAs<TypedefTypeLoc>()) { 5890 const TypedefNameDecl *TDL = TTL.getTypedefNameDecl(); 5891 TInfo = TDL->getTypeSourceInfo(); 5892 continue; 5893 } 5894 if (ConstantArrayTypeLoc CTL = TL.getAs<ConstantArrayTypeLoc>()) { 5895 const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr()); 5896 if (!SizeExpr || SizeExpr->getExprLoc().isMacroID()) 5897 return false; 5898 } 5899 break; 5900 } 5901 5902 const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext()); 5903 if (!RD) return false; 5904 if (RD->isUnion()) return false; 5905 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) { 5906 if (!CRD->isStandardLayout()) return false; 5907 } 5908 5909 // See if this is the last field decl in the record. 5910 const Decl *D = FD; 5911 while ((D = D->getNextDeclInContext())) 5912 if (isa<FieldDecl>(D)) 5913 return false; 5914 return true; 5915} 5916 5917void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr, 5918 const ArraySubscriptExpr *ASE, 5919 bool AllowOnePastEnd, bool IndexNegated) { 5920 IndexExpr = IndexExpr->IgnoreParenImpCasts(); 5921 if (IndexExpr->isValueDependent()) 5922 return; 5923 5924 const Type *EffectiveType = getElementType(BaseExpr); 5925 BaseExpr = BaseExpr->IgnoreParenCasts(); 5926 const ConstantArrayType *ArrayTy = 5927 Context.getAsConstantArrayType(BaseExpr->getType()); 5928 if (!ArrayTy) 5929 return; 5930 5931 llvm::APSInt index; 5932 if (!IndexExpr->EvaluateAsInt(index, Context)) 5933 return; 5934 if (IndexNegated) 5935 index = -index; 5936 5937 const NamedDecl *ND = NULL; 5938 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 5939 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 5940 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 5941 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 5942 5943 if (index.isUnsigned() || !index.isNegative()) { 5944 llvm::APInt size = ArrayTy->getSize(); 5945 if (!size.isStrictlyPositive()) 5946 return; 5947 5948 const Type* BaseType = getElementType(BaseExpr); 5949 if (BaseType != EffectiveType) { 5950 // Make sure we're comparing apples to apples when comparing index to size 5951 uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType); 5952 uint64_t array_typesize = Context.getTypeSize(BaseType); 5953 // Handle ptrarith_typesize being zero, such as when casting to void* 5954 if (!ptrarith_typesize) ptrarith_typesize = 1; 5955 if (ptrarith_typesize != array_typesize) { 5956 // There's a cast to a different size type involved 5957 uint64_t ratio = array_typesize / ptrarith_typesize; 5958 // TODO: Be smarter about handling cases where array_typesize is not a 5959 // multiple of ptrarith_typesize 5960 if (ptrarith_typesize * ratio == array_typesize) 5961 size *= llvm::APInt(size.getBitWidth(), ratio); 5962 } 5963 } 5964 5965 if (size.getBitWidth() > index.getBitWidth()) 5966 index = index.zext(size.getBitWidth()); 5967 else if (size.getBitWidth() < index.getBitWidth()) 5968 size = size.zext(index.getBitWidth()); 5969 5970 // For array subscripting the index must be less than size, but for pointer 5971 // arithmetic also allow the index (offset) to be equal to size since 5972 // computing the next address after the end of the array is legal and 5973 // commonly done e.g. in C++ iterators and range-based for loops. 5974 if (AllowOnePastEnd ? index.ule(size) : index.ult(size)) 5975 return; 5976 5977 // Also don't warn for arrays of size 1 which are members of some 5978 // structure. These are often used to approximate flexible arrays in C89 5979 // code. 5980 if (IsTailPaddedMemberArray(*this, size, ND)) 5981 return; 5982 5983 // Suppress the warning if the subscript expression (as identified by the 5984 // ']' location) and the index expression are both from macro expansions 5985 // within a system header. 5986 if (ASE) { 5987 SourceLocation RBracketLoc = SourceMgr.getSpellingLoc( 5988 ASE->getRBracketLoc()); 5989 if (SourceMgr.isInSystemHeader(RBracketLoc)) { 5990 SourceLocation IndexLoc = SourceMgr.getSpellingLoc( 5991 IndexExpr->getLocStart()); 5992 if (SourceMgr.isFromSameFile(RBracketLoc, IndexLoc)) 5993 return; 5994 } 5995 } 5996 5997 unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds; 5998 if (ASE) 5999 DiagID = diag::warn_array_index_exceeds_bounds; 6000 6001 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 6002 PDiag(DiagID) << index.toString(10, true) 6003 << size.toString(10, true) 6004 << (unsigned)size.getLimitedValue(~0U) 6005 << IndexExpr->getSourceRange()); 6006 } else { 6007 unsigned DiagID = diag::warn_array_index_precedes_bounds; 6008 if (!ASE) { 6009 DiagID = diag::warn_ptr_arith_precedes_bounds; 6010 if (index.isNegative()) index = -index; 6011 } 6012 6013 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 6014 PDiag(DiagID) << index.toString(10, true) 6015 << IndexExpr->getSourceRange()); 6016 } 6017 6018 if (!ND) { 6019 // Try harder to find a NamedDecl to point at in the note. 6020 while (const ArraySubscriptExpr *ASE = 6021 dyn_cast<ArraySubscriptExpr>(BaseExpr)) 6022 BaseExpr = ASE->getBase()->IgnoreParenCasts(); 6023 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 6024 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 6025 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 6026 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 6027 } 6028 6029 if (ND) 6030 DiagRuntimeBehavior(ND->getLocStart(), BaseExpr, 6031 PDiag(diag::note_array_index_out_of_bounds) 6032 << ND->getDeclName()); 6033} 6034 6035void Sema::CheckArrayAccess(const Expr *expr) { 6036 int AllowOnePastEnd = 0; 6037 while (expr) { 6038 expr = expr->IgnoreParenImpCasts(); 6039 switch (expr->getStmtClass()) { 6040 case Stmt::ArraySubscriptExprClass: { 6041 const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr); 6042 CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE, 6043 AllowOnePastEnd > 0); 6044 return; 6045 } 6046 case Stmt::UnaryOperatorClass: { 6047 // Only unwrap the * and & unary operators 6048 const UnaryOperator *UO = cast<UnaryOperator>(expr); 6049 expr = UO->getSubExpr(); 6050 switch (UO->getOpcode()) { 6051 case UO_AddrOf: 6052 AllowOnePastEnd++; 6053 break; 6054 case UO_Deref: 6055 AllowOnePastEnd--; 6056 break; 6057 default: 6058 return; 6059 } 6060 break; 6061 } 6062 case Stmt::ConditionalOperatorClass: { 6063 const ConditionalOperator *cond = cast<ConditionalOperator>(expr); 6064 if (const Expr *lhs = cond->getLHS()) 6065 CheckArrayAccess(lhs); 6066 if (const Expr *rhs = cond->getRHS()) 6067 CheckArrayAccess(rhs); 6068 return; 6069 } 6070 default: 6071 return; 6072 } 6073 } 6074} 6075 6076//===--- CHECK: Objective-C retain cycles ----------------------------------// 6077 6078namespace { 6079 struct RetainCycleOwner { 6080 RetainCycleOwner() : Variable(0), Indirect(false) {} 6081 VarDecl *Variable; 6082 SourceRange Range; 6083 SourceLocation Loc; 6084 bool Indirect; 6085 6086 void setLocsFrom(Expr *e) { 6087 Loc = e->getExprLoc(); 6088 Range = e->getSourceRange(); 6089 } 6090 }; 6091} 6092 6093/// Consider whether capturing the given variable can possibly lead to 6094/// a retain cycle. 6095static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) { 6096 // In ARC, it's captured strongly iff the variable has __strong 6097 // lifetime. In MRR, it's captured strongly if the variable is 6098 // __block and has an appropriate type. 6099 if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 6100 return false; 6101 6102 owner.Variable = var; 6103 if (ref) 6104 owner.setLocsFrom(ref); 6105 return true; 6106} 6107 6108static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) { 6109 while (true) { 6110 e = e->IgnoreParens(); 6111 if (CastExpr *cast = dyn_cast<CastExpr>(e)) { 6112 switch (cast->getCastKind()) { 6113 case CK_BitCast: 6114 case CK_LValueBitCast: 6115 case CK_LValueToRValue: 6116 case CK_ARCReclaimReturnedObject: 6117 e = cast->getSubExpr(); 6118 continue; 6119 6120 default: 6121 return false; 6122 } 6123 } 6124 6125 if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) { 6126 ObjCIvarDecl *ivar = ref->getDecl(); 6127 if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 6128 return false; 6129 6130 // Try to find a retain cycle in the base. 6131 if (!findRetainCycleOwner(S, ref->getBase(), owner)) 6132 return false; 6133 6134 if (ref->isFreeIvar()) owner.setLocsFrom(ref); 6135 owner.Indirect = true; 6136 return true; 6137 } 6138 6139 if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) { 6140 VarDecl *var = dyn_cast<VarDecl>(ref->getDecl()); 6141 if (!var) return false; 6142 return considerVariable(var, ref, owner); 6143 } 6144 6145 if (MemberExpr *member = dyn_cast<MemberExpr>(e)) { 6146 if (member->isArrow()) return false; 6147 6148 // Don't count this as an indirect ownership. 6149 e = member->getBase(); 6150 continue; 6151 } 6152 6153 if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) { 6154 // Only pay attention to pseudo-objects on property references. 6155 ObjCPropertyRefExpr *pre 6156 = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm() 6157 ->IgnoreParens()); 6158 if (!pre) return false; 6159 if (pre->isImplicitProperty()) return false; 6160 ObjCPropertyDecl *property = pre->getExplicitProperty(); 6161 if (!property->isRetaining() && 6162 !(property->getPropertyIvarDecl() && 6163 property->getPropertyIvarDecl()->getType() 6164 .getObjCLifetime() == Qualifiers::OCL_Strong)) 6165 return false; 6166 6167 owner.Indirect = true; 6168 if (pre->isSuperReceiver()) { 6169 owner.Variable = S.getCurMethodDecl()->getSelfDecl(); 6170 if (!owner.Variable) 6171 return false; 6172 owner.Loc = pre->getLocation(); 6173 owner.Range = pre->getSourceRange(); 6174 return true; 6175 } 6176 e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase()) 6177 ->getSourceExpr()); 6178 continue; 6179 } 6180 6181 // Array ivars? 6182 6183 return false; 6184 } 6185} 6186 6187namespace { 6188 struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> { 6189 FindCaptureVisitor(ASTContext &Context, VarDecl *variable) 6190 : EvaluatedExprVisitor<FindCaptureVisitor>(Context), 6191 Variable(variable), Capturer(0) {} 6192 6193 VarDecl *Variable; 6194 Expr *Capturer; 6195 6196 void VisitDeclRefExpr(DeclRefExpr *ref) { 6197 if (ref->getDecl() == Variable && !Capturer) 6198 Capturer = ref; 6199 } 6200 6201 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) { 6202 if (Capturer) return; 6203 Visit(ref->getBase()); 6204 if (Capturer && ref->isFreeIvar()) 6205 Capturer = ref; 6206 } 6207 6208 void VisitBlockExpr(BlockExpr *block) { 6209 // Look inside nested blocks 6210 if (block->getBlockDecl()->capturesVariable(Variable)) 6211 Visit(block->getBlockDecl()->getBody()); 6212 } 6213 6214 void VisitOpaqueValueExpr(OpaqueValueExpr *OVE) { 6215 if (Capturer) return; 6216 if (OVE->getSourceExpr()) 6217 Visit(OVE->getSourceExpr()); 6218 } 6219 }; 6220} 6221 6222/// Check whether the given argument is a block which captures a 6223/// variable. 6224static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) { 6225 assert(owner.Variable && owner.Loc.isValid()); 6226 6227 e = e->IgnoreParenCasts(); 6228 6229 // Look through [^{...} copy] and Block_copy(^{...}). 6230 if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(e)) { 6231 Selector Cmd = ME->getSelector(); 6232 if (Cmd.isUnarySelector() && Cmd.getNameForSlot(0) == "copy") { 6233 e = ME->getInstanceReceiver(); 6234 if (!e) 6235 return 0; 6236 e = e->IgnoreParenCasts(); 6237 } 6238 } else if (CallExpr *CE = dyn_cast<CallExpr>(e)) { 6239 if (CE->getNumArgs() == 1) { 6240 FunctionDecl *Fn = dyn_cast_or_null<FunctionDecl>(CE->getCalleeDecl()); 6241 if (Fn) { 6242 const IdentifierInfo *FnI = Fn->getIdentifier(); 6243 if (FnI && FnI->isStr("_Block_copy")) { 6244 e = CE->getArg(0)->IgnoreParenCasts(); 6245 } 6246 } 6247 } 6248 } 6249 6250 BlockExpr *block = dyn_cast<BlockExpr>(e); 6251 if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable)) 6252 return 0; 6253 6254 FindCaptureVisitor visitor(S.Context, owner.Variable); 6255 visitor.Visit(block->getBlockDecl()->getBody()); 6256 return visitor.Capturer; 6257} 6258 6259static void diagnoseRetainCycle(Sema &S, Expr *capturer, 6260 RetainCycleOwner &owner) { 6261 assert(capturer); 6262 assert(owner.Variable && owner.Loc.isValid()); 6263 6264 S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle) 6265 << owner.Variable << capturer->getSourceRange(); 6266 S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner) 6267 << owner.Indirect << owner.Range; 6268} 6269 6270/// Check for a keyword selector that starts with the word 'add' or 6271/// 'set'. 6272static bool isSetterLikeSelector(Selector sel) { 6273 if (sel.isUnarySelector()) return false; 6274 6275 StringRef str = sel.getNameForSlot(0); 6276 while (!str.empty() && str.front() == '_') str = str.substr(1); 6277 if (str.startswith("set")) 6278 str = str.substr(3); 6279 else if (str.startswith("add")) { 6280 // Specially whitelist 'addOperationWithBlock:'. 6281 if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock")) 6282 return false; 6283 str = str.substr(3); 6284 } 6285 else 6286 return false; 6287 6288 if (str.empty()) return true; 6289 return !isLowercase(str.front()); 6290} 6291 6292/// Check a message send to see if it's likely to cause a retain cycle. 6293void Sema::checkRetainCycles(ObjCMessageExpr *msg) { 6294 // Only check instance methods whose selector looks like a setter. 6295 if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector())) 6296 return; 6297 6298 // Try to find a variable that the receiver is strongly owned by. 6299 RetainCycleOwner owner; 6300 if (msg->getReceiverKind() == ObjCMessageExpr::Instance) { 6301 if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner)) 6302 return; 6303 } else { 6304 assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance); 6305 owner.Variable = getCurMethodDecl()->getSelfDecl(); 6306 owner.Loc = msg->getSuperLoc(); 6307 owner.Range = msg->getSuperLoc(); 6308 } 6309 6310 // Check whether the receiver is captured by any of the arguments. 6311 for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i) 6312 if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner)) 6313 return diagnoseRetainCycle(*this, capturer, owner); 6314} 6315 6316/// Check a property assign to see if it's likely to cause a retain cycle. 6317void Sema::checkRetainCycles(Expr *receiver, Expr *argument) { 6318 RetainCycleOwner owner; 6319 if (!findRetainCycleOwner(*this, receiver, owner)) 6320 return; 6321 6322 if (Expr *capturer = findCapturingExpr(*this, argument, owner)) 6323 diagnoseRetainCycle(*this, capturer, owner); 6324} 6325 6326void Sema::checkRetainCycles(VarDecl *Var, Expr *Init) { 6327 RetainCycleOwner Owner; 6328 if (!considerVariable(Var, /*DeclRefExpr=*/0, Owner)) 6329 return; 6330 6331 // Because we don't have an expression for the variable, we have to set the 6332 // location explicitly here. 6333 Owner.Loc = Var->getLocation(); 6334 Owner.Range = Var->getSourceRange(); 6335 6336 if (Expr *Capturer = findCapturingExpr(*this, Init, Owner)) 6337 diagnoseRetainCycle(*this, Capturer, Owner); 6338} 6339 6340static bool checkUnsafeAssignLiteral(Sema &S, SourceLocation Loc, 6341 Expr *RHS, bool isProperty) { 6342 // Check if RHS is an Objective-C object literal, which also can get 6343 // immediately zapped in a weak reference. Note that we explicitly 6344 // allow ObjCStringLiterals, since those are designed to never really die. 6345 RHS = RHS->IgnoreParenImpCasts(); 6346 6347 // This enum needs to match with the 'select' in 6348 // warn_objc_arc_literal_assign (off-by-1). 6349 Sema::ObjCLiteralKind Kind = S.CheckLiteralKind(RHS); 6350 if (Kind == Sema::LK_String || Kind == Sema::LK_None) 6351 return false; 6352 6353 S.Diag(Loc, diag::warn_arc_literal_assign) 6354 << (unsigned) Kind 6355 << (isProperty ? 0 : 1) 6356 << RHS->getSourceRange(); 6357 6358 return true; 6359} 6360 6361static bool checkUnsafeAssignObject(Sema &S, SourceLocation Loc, 6362 Qualifiers::ObjCLifetime LT, 6363 Expr *RHS, bool isProperty) { 6364 // Strip off any implicit cast added to get to the one ARC-specific. 6365 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 6366 if (cast->getCastKind() == CK_ARCConsumeObject) { 6367 S.Diag(Loc, diag::warn_arc_retained_assign) 6368 << (LT == Qualifiers::OCL_ExplicitNone) 6369 << (isProperty ? 0 : 1) 6370 << RHS->getSourceRange(); 6371 return true; 6372 } 6373 RHS = cast->getSubExpr(); 6374 } 6375 6376 if (LT == Qualifiers::OCL_Weak && 6377 checkUnsafeAssignLiteral(S, Loc, RHS, isProperty)) 6378 return true; 6379 6380 return false; 6381} 6382 6383bool Sema::checkUnsafeAssigns(SourceLocation Loc, 6384 QualType LHS, Expr *RHS) { 6385 Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime(); 6386 6387 if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone) 6388 return false; 6389 6390 if (checkUnsafeAssignObject(*this, Loc, LT, RHS, false)) 6391 return true; 6392 6393 return false; 6394} 6395 6396void Sema::checkUnsafeExprAssigns(SourceLocation Loc, 6397 Expr *LHS, Expr *RHS) { 6398 QualType LHSType; 6399 // PropertyRef on LHS type need be directly obtained from 6400 // its declaration as it has a PsuedoType. 6401 ObjCPropertyRefExpr *PRE 6402 = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens()); 6403 if (PRE && !PRE->isImplicitProperty()) { 6404 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 6405 if (PD) 6406 LHSType = PD->getType(); 6407 } 6408 6409 if (LHSType.isNull()) 6410 LHSType = LHS->getType(); 6411 6412 Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime(); 6413 6414 if (LT == Qualifiers::OCL_Weak) { 6415 DiagnosticsEngine::Level Level = 6416 Diags.getDiagnosticLevel(diag::warn_arc_repeated_use_of_weak, Loc); 6417 if (Level != DiagnosticsEngine::Ignored) 6418 getCurFunction()->markSafeWeakUse(LHS); 6419 } 6420 6421 if (checkUnsafeAssigns(Loc, LHSType, RHS)) 6422 return; 6423 6424 // FIXME. Check for other life times. 6425 if (LT != Qualifiers::OCL_None) 6426 return; 6427 6428 if (PRE) { 6429 if (PRE->isImplicitProperty()) 6430 return; 6431 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 6432 if (!PD) 6433 return; 6434 6435 unsigned Attributes = PD->getPropertyAttributes(); 6436 if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) { 6437 // when 'assign' attribute was not explicitly specified 6438 // by user, ignore it and rely on property type itself 6439 // for lifetime info. 6440 unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten(); 6441 if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) && 6442 LHSType->isObjCRetainableType()) 6443 return; 6444 6445 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 6446 if (cast->getCastKind() == CK_ARCConsumeObject) { 6447 Diag(Loc, diag::warn_arc_retained_property_assign) 6448 << RHS->getSourceRange(); 6449 return; 6450 } 6451 RHS = cast->getSubExpr(); 6452 } 6453 } 6454 else if (Attributes & ObjCPropertyDecl::OBJC_PR_weak) { 6455 if (checkUnsafeAssignObject(*this, Loc, Qualifiers::OCL_Weak, RHS, true)) 6456 return; 6457 } 6458 } 6459} 6460 6461//===--- CHECK: Empty statement body (-Wempty-body) ---------------------===// 6462 6463namespace { 6464bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr, 6465 SourceLocation StmtLoc, 6466 const NullStmt *Body) { 6467 // Do not warn if the body is a macro that expands to nothing, e.g: 6468 // 6469 // #define CALL(x) 6470 // if (condition) 6471 // CALL(0); 6472 // 6473 if (Body->hasLeadingEmptyMacro()) 6474 return false; 6475 6476 // Get line numbers of statement and body. 6477 bool StmtLineInvalid; 6478 unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc, 6479 &StmtLineInvalid); 6480 if (StmtLineInvalid) 6481 return false; 6482 6483 bool BodyLineInvalid; 6484 unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(), 6485 &BodyLineInvalid); 6486 if (BodyLineInvalid) 6487 return false; 6488 6489 // Warn if null statement and body are on the same line. 6490 if (StmtLine != BodyLine) 6491 return false; 6492 6493 return true; 6494} 6495} // Unnamed namespace 6496 6497void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc, 6498 const Stmt *Body, 6499 unsigned DiagID) { 6500 // Since this is a syntactic check, don't emit diagnostic for template 6501 // instantiations, this just adds noise. 6502 if (CurrentInstantiationScope) 6503 return; 6504 6505 // The body should be a null statement. 6506 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 6507 if (!NBody) 6508 return; 6509 6510 // Do the usual checks. 6511 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 6512 return; 6513 6514 Diag(NBody->getSemiLoc(), DiagID); 6515 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 6516} 6517 6518void Sema::DiagnoseEmptyLoopBody(const Stmt *S, 6519 const Stmt *PossibleBody) { 6520 assert(!CurrentInstantiationScope); // Ensured by caller 6521 6522 SourceLocation StmtLoc; 6523 const Stmt *Body; 6524 unsigned DiagID; 6525 if (const ForStmt *FS = dyn_cast<ForStmt>(S)) { 6526 StmtLoc = FS->getRParenLoc(); 6527 Body = FS->getBody(); 6528 DiagID = diag::warn_empty_for_body; 6529 } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) { 6530 StmtLoc = WS->getCond()->getSourceRange().getEnd(); 6531 Body = WS->getBody(); 6532 DiagID = diag::warn_empty_while_body; 6533 } else 6534 return; // Neither `for' nor `while'. 6535 6536 // The body should be a null statement. 6537 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 6538 if (!NBody) 6539 return; 6540 6541 // Skip expensive checks if diagnostic is disabled. 6542 if (Diags.getDiagnosticLevel(DiagID, NBody->getSemiLoc()) == 6543 DiagnosticsEngine::Ignored) 6544 return; 6545 6546 // Do the usual checks. 6547 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 6548 return; 6549 6550 // `for(...);' and `while(...);' are popular idioms, so in order to keep 6551 // noise level low, emit diagnostics only if for/while is followed by a 6552 // CompoundStmt, e.g.: 6553 // for (int i = 0; i < n; i++); 6554 // { 6555 // a(i); 6556 // } 6557 // or if for/while is followed by a statement with more indentation 6558 // than for/while itself: 6559 // for (int i = 0; i < n; i++); 6560 // a(i); 6561 bool ProbableTypo = isa<CompoundStmt>(PossibleBody); 6562 if (!ProbableTypo) { 6563 bool BodyColInvalid; 6564 unsigned BodyCol = SourceMgr.getPresumedColumnNumber( 6565 PossibleBody->getLocStart(), 6566 &BodyColInvalid); 6567 if (BodyColInvalid) 6568 return; 6569 6570 bool StmtColInvalid; 6571 unsigned StmtCol = SourceMgr.getPresumedColumnNumber( 6572 S->getLocStart(), 6573 &StmtColInvalid); 6574 if (StmtColInvalid) 6575 return; 6576 6577 if (BodyCol > StmtCol) 6578 ProbableTypo = true; 6579 } 6580 6581 if (ProbableTypo) { 6582 Diag(NBody->getSemiLoc(), DiagID); 6583 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 6584 } 6585} 6586 6587//===--- Layout compatibility ----------------------------------------------// 6588 6589namespace { 6590 6591bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2); 6592 6593/// \brief Check if two enumeration types are layout-compatible. 6594bool isLayoutCompatible(ASTContext &C, EnumDecl *ED1, EnumDecl *ED2) { 6595 // C++11 [dcl.enum] p8: 6596 // Two enumeration types are layout-compatible if they have the same 6597 // underlying type. 6598 return ED1->isComplete() && ED2->isComplete() && 6599 C.hasSameType(ED1->getIntegerType(), ED2->getIntegerType()); 6600} 6601 6602/// \brief Check if two fields are layout-compatible. 6603bool isLayoutCompatible(ASTContext &C, FieldDecl *Field1, FieldDecl *Field2) { 6604 if (!isLayoutCompatible(C, Field1->getType(), Field2->getType())) 6605 return false; 6606 6607 if (Field1->isBitField() != Field2->isBitField()) 6608 return false; 6609 6610 if (Field1->isBitField()) { 6611 // Make sure that the bit-fields are the same length. 6612 unsigned Bits1 = Field1->getBitWidthValue(C); 6613 unsigned Bits2 = Field2->getBitWidthValue(C); 6614 6615 if (Bits1 != Bits2) 6616 return false; 6617 } 6618 6619 return true; 6620} 6621 6622/// \brief Check if two standard-layout structs are layout-compatible. 6623/// (C++11 [class.mem] p17) 6624bool isLayoutCompatibleStruct(ASTContext &C, 6625 RecordDecl *RD1, 6626 RecordDecl *RD2) { 6627 // If both records are C++ classes, check that base classes match. 6628 if (const CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(RD1)) { 6629 // If one of records is a CXXRecordDecl we are in C++ mode, 6630 // thus the other one is a CXXRecordDecl, too. 6631 const CXXRecordDecl *D2CXX = cast<CXXRecordDecl>(RD2); 6632 // Check number of base classes. 6633 if (D1CXX->getNumBases() != D2CXX->getNumBases()) 6634 return false; 6635 6636 // Check the base classes. 6637 for (CXXRecordDecl::base_class_const_iterator 6638 Base1 = D1CXX->bases_begin(), 6639 BaseEnd1 = D1CXX->bases_end(), 6640 Base2 = D2CXX->bases_begin(); 6641 Base1 != BaseEnd1; 6642 ++Base1, ++Base2) { 6643 if (!isLayoutCompatible(C, Base1->getType(), Base2->getType())) 6644 return false; 6645 } 6646 } else if (const CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(RD2)) { 6647 // If only RD2 is a C++ class, it should have zero base classes. 6648 if (D2CXX->getNumBases() > 0) 6649 return false; 6650 } 6651 6652 // Check the fields. 6653 RecordDecl::field_iterator Field2 = RD2->field_begin(), 6654 Field2End = RD2->field_end(), 6655 Field1 = RD1->field_begin(), 6656 Field1End = RD1->field_end(); 6657 for ( ; Field1 != Field1End && Field2 != Field2End; ++Field1, ++Field2) { 6658 if (!isLayoutCompatible(C, *Field1, *Field2)) 6659 return false; 6660 } 6661 if (Field1 != Field1End || Field2 != Field2End) 6662 return false; 6663 6664 return true; 6665} 6666 6667/// \brief Check if two standard-layout unions are layout-compatible. 6668/// (C++11 [class.mem] p18) 6669bool isLayoutCompatibleUnion(ASTContext &C, 6670 RecordDecl *RD1, 6671 RecordDecl *RD2) { 6672 llvm::SmallPtrSet<FieldDecl *, 8> UnmatchedFields; 6673 for (RecordDecl::field_iterator Field2 = RD2->field_begin(), 6674 Field2End = RD2->field_end(); 6675 Field2 != Field2End; ++Field2) { 6676 UnmatchedFields.insert(*Field2); 6677 } 6678 6679 for (RecordDecl::field_iterator Field1 = RD1->field_begin(), 6680 Field1End = RD1->field_end(); 6681 Field1 != Field1End; ++Field1) { 6682 llvm::SmallPtrSet<FieldDecl *, 8>::iterator 6683 I = UnmatchedFields.begin(), 6684 E = UnmatchedFields.end(); 6685 6686 for ( ; I != E; ++I) { 6687 if (isLayoutCompatible(C, *Field1, *I)) { 6688 bool Result = UnmatchedFields.erase(*I); 6689 (void) Result; 6690 assert(Result); 6691 break; 6692 } 6693 } 6694 if (I == E) 6695 return false; 6696 } 6697 6698 return UnmatchedFields.empty(); 6699} 6700 6701bool isLayoutCompatible(ASTContext &C, RecordDecl *RD1, RecordDecl *RD2) { 6702 if (RD1->isUnion() != RD2->isUnion()) 6703 return false; 6704 6705 if (RD1->isUnion()) 6706 return isLayoutCompatibleUnion(C, RD1, RD2); 6707 else 6708 return isLayoutCompatibleStruct(C, RD1, RD2); 6709} 6710 6711/// \brief Check if two types are layout-compatible in C++11 sense. 6712bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2) { 6713 if (T1.isNull() || T2.isNull()) 6714 return false; 6715 6716 // C++11 [basic.types] p11: 6717 // If two types T1 and T2 are the same type, then T1 and T2 are 6718 // layout-compatible types. 6719 if (C.hasSameType(T1, T2)) 6720 return true; 6721 6722 T1 = T1.getCanonicalType().getUnqualifiedType(); 6723 T2 = T2.getCanonicalType().getUnqualifiedType(); 6724 6725 const Type::TypeClass TC1 = T1->getTypeClass(); 6726 const Type::TypeClass TC2 = T2->getTypeClass(); 6727 6728 if (TC1 != TC2) 6729 return false; 6730 6731 if (TC1 == Type::Enum) { 6732 return isLayoutCompatible(C, 6733 cast<EnumType>(T1)->getDecl(), 6734 cast<EnumType>(T2)->getDecl()); 6735 } else if (TC1 == Type::Record) { 6736 if (!T1->isStandardLayoutType() || !T2->isStandardLayoutType()) 6737 return false; 6738 6739 return isLayoutCompatible(C, 6740 cast<RecordType>(T1)->getDecl(), 6741 cast<RecordType>(T2)->getDecl()); 6742 } 6743 6744 return false; 6745} 6746} 6747 6748//===--- CHECK: pointer_with_type_tag attribute: datatypes should match ----// 6749 6750namespace { 6751/// \brief Given a type tag expression find the type tag itself. 6752/// 6753/// \param TypeExpr Type tag expression, as it appears in user's code. 6754/// 6755/// \param VD Declaration of an identifier that appears in a type tag. 6756/// 6757/// \param MagicValue Type tag magic value. 6758bool FindTypeTagExpr(const Expr *TypeExpr, const ASTContext &Ctx, 6759 const ValueDecl **VD, uint64_t *MagicValue) { 6760 while(true) { 6761 if (!TypeExpr) 6762 return false; 6763 6764 TypeExpr = TypeExpr->IgnoreParenImpCasts()->IgnoreParenCasts(); 6765 6766 switch (TypeExpr->getStmtClass()) { 6767 case Stmt::UnaryOperatorClass: { 6768 const UnaryOperator *UO = cast<UnaryOperator>(TypeExpr); 6769 if (UO->getOpcode() == UO_AddrOf || UO->getOpcode() == UO_Deref) { 6770 TypeExpr = UO->getSubExpr(); 6771 continue; 6772 } 6773 return false; 6774 } 6775 6776 case Stmt::DeclRefExprClass: { 6777 const DeclRefExpr *DRE = cast<DeclRefExpr>(TypeExpr); 6778 *VD = DRE->getDecl(); 6779 return true; 6780 } 6781 6782 case Stmt::IntegerLiteralClass: { 6783 const IntegerLiteral *IL = cast<IntegerLiteral>(TypeExpr); 6784 llvm::APInt MagicValueAPInt = IL->getValue(); 6785 if (MagicValueAPInt.getActiveBits() <= 64) { 6786 *MagicValue = MagicValueAPInt.getZExtValue(); 6787 return true; 6788 } else 6789 return false; 6790 } 6791 6792 case Stmt::BinaryConditionalOperatorClass: 6793 case Stmt::ConditionalOperatorClass: { 6794 const AbstractConditionalOperator *ACO = 6795 cast<AbstractConditionalOperator>(TypeExpr); 6796 bool Result; 6797 if (ACO->getCond()->EvaluateAsBooleanCondition(Result, Ctx)) { 6798 if (Result) 6799 TypeExpr = ACO->getTrueExpr(); 6800 else 6801 TypeExpr = ACO->getFalseExpr(); 6802 continue; 6803 } 6804 return false; 6805 } 6806 6807 case Stmt::BinaryOperatorClass: { 6808 const BinaryOperator *BO = cast<BinaryOperator>(TypeExpr); 6809 if (BO->getOpcode() == BO_Comma) { 6810 TypeExpr = BO->getRHS(); 6811 continue; 6812 } 6813 return false; 6814 } 6815 6816 default: 6817 return false; 6818 } 6819 } 6820} 6821 6822/// \brief Retrieve the C type corresponding to type tag TypeExpr. 6823/// 6824/// \param TypeExpr Expression that specifies a type tag. 6825/// 6826/// \param MagicValues Registered magic values. 6827/// 6828/// \param FoundWrongKind Set to true if a type tag was found, but of a wrong 6829/// kind. 6830/// 6831/// \param TypeInfo Information about the corresponding C type. 6832/// 6833/// \returns true if the corresponding C type was found. 6834bool GetMatchingCType( 6835 const IdentifierInfo *ArgumentKind, 6836 const Expr *TypeExpr, const ASTContext &Ctx, 6837 const llvm::DenseMap<Sema::TypeTagMagicValue, 6838 Sema::TypeTagData> *MagicValues, 6839 bool &FoundWrongKind, 6840 Sema::TypeTagData &TypeInfo) { 6841 FoundWrongKind = false; 6842 6843 // Variable declaration that has type_tag_for_datatype attribute. 6844 const ValueDecl *VD = NULL; 6845 6846 uint64_t MagicValue; 6847 6848 if (!FindTypeTagExpr(TypeExpr, Ctx, &VD, &MagicValue)) 6849 return false; 6850 6851 if (VD) { 6852 for (specific_attr_iterator<TypeTagForDatatypeAttr> 6853 I = VD->specific_attr_begin<TypeTagForDatatypeAttr>(), 6854 E = VD->specific_attr_end<TypeTagForDatatypeAttr>(); 6855 I != E; ++I) { 6856 if (I->getArgumentKind() != ArgumentKind) { 6857 FoundWrongKind = true; 6858 return false; 6859 } 6860 TypeInfo.Type = I->getMatchingCType(); 6861 TypeInfo.LayoutCompatible = I->getLayoutCompatible(); 6862 TypeInfo.MustBeNull = I->getMustBeNull(); 6863 return true; 6864 } 6865 return false; 6866 } 6867 6868 if (!MagicValues) 6869 return false; 6870 6871 llvm::DenseMap<Sema::TypeTagMagicValue, 6872 Sema::TypeTagData>::const_iterator I = 6873 MagicValues->find(std::make_pair(ArgumentKind, MagicValue)); 6874 if (I == MagicValues->end()) 6875 return false; 6876 6877 TypeInfo = I->second; 6878 return true; 6879} 6880} // unnamed namespace 6881 6882void Sema::RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind, 6883 uint64_t MagicValue, QualType Type, 6884 bool LayoutCompatible, 6885 bool MustBeNull) { 6886 if (!TypeTagForDatatypeMagicValues) 6887 TypeTagForDatatypeMagicValues.reset( 6888 new llvm::DenseMap<TypeTagMagicValue, TypeTagData>); 6889 6890 TypeTagMagicValue Magic(ArgumentKind, MagicValue); 6891 (*TypeTagForDatatypeMagicValues)[Magic] = 6892 TypeTagData(Type, LayoutCompatible, MustBeNull); 6893} 6894 6895namespace { 6896bool IsSameCharType(QualType T1, QualType T2) { 6897 const BuiltinType *BT1 = T1->getAs<BuiltinType>(); 6898 if (!BT1) 6899 return false; 6900 6901 const BuiltinType *BT2 = T2->getAs<BuiltinType>(); 6902 if (!BT2) 6903 return false; 6904 6905 BuiltinType::Kind T1Kind = BT1->getKind(); 6906 BuiltinType::Kind T2Kind = BT2->getKind(); 6907 6908 return (T1Kind == BuiltinType::SChar && T2Kind == BuiltinType::Char_S) || 6909 (T1Kind == BuiltinType::UChar && T2Kind == BuiltinType::Char_U) || 6910 (T1Kind == BuiltinType::Char_U && T2Kind == BuiltinType::UChar) || 6911 (T1Kind == BuiltinType::Char_S && T2Kind == BuiltinType::SChar); 6912} 6913} // unnamed namespace 6914 6915void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr, 6916 const Expr * const *ExprArgs) { 6917 const IdentifierInfo *ArgumentKind = Attr->getArgumentKind(); 6918 bool IsPointerAttr = Attr->getIsPointer(); 6919 6920 const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()]; 6921 bool FoundWrongKind; 6922 TypeTagData TypeInfo; 6923 if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context, 6924 TypeTagForDatatypeMagicValues.get(), 6925 FoundWrongKind, TypeInfo)) { 6926 if (FoundWrongKind) 6927 Diag(TypeTagExpr->getExprLoc(), 6928 diag::warn_type_tag_for_datatype_wrong_kind) 6929 << TypeTagExpr->getSourceRange(); 6930 return; 6931 } 6932 6933 const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()]; 6934 if (IsPointerAttr) { 6935 // Skip implicit cast of pointer to `void *' (as a function argument). 6936 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr)) 6937 if (ICE->getType()->isVoidPointerType() && 6938 ICE->getCastKind() == CK_BitCast) 6939 ArgumentExpr = ICE->getSubExpr(); 6940 } 6941 QualType ArgumentType = ArgumentExpr->getType(); 6942 6943 // Passing a `void*' pointer shouldn't trigger a warning. 6944 if (IsPointerAttr && ArgumentType->isVoidPointerType()) 6945 return; 6946 6947 if (TypeInfo.MustBeNull) { 6948 // Type tag with matching void type requires a null pointer. 6949 if (!ArgumentExpr->isNullPointerConstant(Context, 6950 Expr::NPC_ValueDependentIsNotNull)) { 6951 Diag(ArgumentExpr->getExprLoc(), 6952 diag::warn_type_safety_null_pointer_required) 6953 << ArgumentKind->getName() 6954 << ArgumentExpr->getSourceRange() 6955 << TypeTagExpr->getSourceRange(); 6956 } 6957 return; 6958 } 6959 6960 QualType RequiredType = TypeInfo.Type; 6961 if (IsPointerAttr) 6962 RequiredType = Context.getPointerType(RequiredType); 6963 6964 bool mismatch = false; 6965 if (!TypeInfo.LayoutCompatible) { 6966 mismatch = !Context.hasSameType(ArgumentType, RequiredType); 6967 6968 // C++11 [basic.fundamental] p1: 6969 // Plain char, signed char, and unsigned char are three distinct types. 6970 // 6971 // But we treat plain `char' as equivalent to `signed char' or `unsigned 6972 // char' depending on the current char signedness mode. 6973 if (mismatch) 6974 if ((IsPointerAttr && IsSameCharType(ArgumentType->getPointeeType(), 6975 RequiredType->getPointeeType())) || 6976 (!IsPointerAttr && IsSameCharType(ArgumentType, RequiredType))) 6977 mismatch = false; 6978 } else 6979 if (IsPointerAttr) 6980 mismatch = !isLayoutCompatible(Context, 6981 ArgumentType->getPointeeType(), 6982 RequiredType->getPointeeType()); 6983 else 6984 mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType); 6985 6986 if (mismatch) 6987 Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch) 6988 << ArgumentType << ArgumentKind->getName() 6989 << TypeInfo.LayoutCompatible << RequiredType 6990 << ArgumentExpr->getSourceRange() 6991 << TypeTagExpr->getSourceRange(); 6992} 6993