SemaChecking.cpp revision 6f2a9fa0f787d3023b643496e8c321bdb7a85fa0
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 for (specific_attr_iterator<FormatAttr> 503 I = FDecl->specific_attr_begin<FormatAttr>(), 504 E = FDecl->specific_attr_end<FormatAttr>(); I != E ; ++I) 505 if (CheckFormatArguments(*I, Args, IsMemberFunction, CallType, Loc, Range)) 506 HandledFormatString = true; 507 508 // Refuse POD arguments that weren't caught by the format string 509 // checks above. 510 if (!HandledFormatString && CallType != VariadicDoesNotApply) 511 for (unsigned ArgIdx = NumProtoArgs; ArgIdx < Args.size(); ++ArgIdx) { 512 // Args[ArgIdx] can be null in malformed code. 513 if (const Expr *Arg = Args[ArgIdx]) 514 variadicArgumentPODCheck(Arg, CallType); 515 } 516 517 for (specific_attr_iterator<NonNullAttr> 518 I = FDecl->specific_attr_begin<NonNullAttr>(), 519 E = FDecl->specific_attr_end<NonNullAttr>(); I != E; ++I) 520 CheckNonNullArguments(*I, Args.data(), Loc); 521 522 // Type safety checking. 523 for (specific_attr_iterator<ArgumentWithTypeTagAttr> 524 i = FDecl->specific_attr_begin<ArgumentWithTypeTagAttr>(), 525 e = FDecl->specific_attr_end<ArgumentWithTypeTagAttr>(); i != e; ++i) { 526 CheckArgumentWithTypeTag(*i, Args.data()); 527 } 528} 529 530/// CheckConstructorCall - Check a constructor call for correctness and safety 531/// properties not enforced by the C type system. 532void Sema::CheckConstructorCall(FunctionDecl *FDecl, 533 ArrayRef<const Expr *> Args, 534 const FunctionProtoType *Proto, 535 SourceLocation Loc) { 536 VariadicCallType CallType = 537 Proto->isVariadic() ? VariadicConstructor : VariadicDoesNotApply; 538 checkCall(FDecl, Args, Proto->getNumArgs(), 539 /*IsMemberFunction=*/true, Loc, SourceRange(), CallType); 540} 541 542/// CheckFunctionCall - Check a direct function call for various correctness 543/// and safety properties not strictly enforced by the C type system. 544bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall, 545 const FunctionProtoType *Proto) { 546 bool IsMemberOperatorCall = isa<CXXOperatorCallExpr>(TheCall) && 547 isa<CXXMethodDecl>(FDecl); 548 bool IsMemberFunction = isa<CXXMemberCallExpr>(TheCall) || 549 IsMemberOperatorCall; 550 VariadicCallType CallType = getVariadicCallType(FDecl, Proto, 551 TheCall->getCallee()); 552 unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0; 553 Expr** Args = TheCall->getArgs(); 554 unsigned NumArgs = TheCall->getNumArgs(); 555 if (IsMemberOperatorCall) { 556 // If this is a call to a member operator, hide the first argument 557 // from checkCall. 558 // FIXME: Our choice of AST representation here is less than ideal. 559 ++Args; 560 --NumArgs; 561 } 562 checkCall(FDecl, llvm::makeArrayRef<const Expr *>(Args, NumArgs), 563 NumProtoArgs, 564 IsMemberFunction, TheCall->getRParenLoc(), 565 TheCall->getCallee()->getSourceRange(), CallType); 566 567 IdentifierInfo *FnInfo = FDecl->getIdentifier(); 568 // None of the checks below are needed for functions that don't have 569 // simple names (e.g., C++ conversion functions). 570 if (!FnInfo) 571 return false; 572 573 unsigned CMId = FDecl->getMemoryFunctionKind(); 574 if (CMId == 0) 575 return false; 576 577 // Handle memory setting and copying functions. 578 if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat) 579 CheckStrlcpycatArguments(TheCall, FnInfo); 580 else if (CMId == Builtin::BIstrncat) 581 CheckStrncatArguments(TheCall, FnInfo); 582 else 583 CheckMemaccessArguments(TheCall, CMId, FnInfo); 584 585 return false; 586} 587 588bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac, 589 ArrayRef<const Expr *> Args) { 590 VariadicCallType CallType = 591 Method->isVariadic() ? VariadicMethod : VariadicDoesNotApply; 592 593 checkCall(Method, Args, Method->param_size(), 594 /*IsMemberFunction=*/false, 595 lbrac, Method->getSourceRange(), CallType); 596 597 return false; 598} 599 600bool Sema::CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall, 601 const FunctionProtoType *Proto) { 602 const VarDecl *V = dyn_cast<VarDecl>(NDecl); 603 if (!V) 604 return false; 605 606 QualType Ty = V->getType(); 607 if (!Ty->isBlockPointerType()) 608 return false; 609 610 VariadicCallType CallType = 611 Proto && Proto->isVariadic() ? VariadicBlock : VariadicDoesNotApply ; 612 unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0; 613 614 checkCall(NDecl, 615 llvm::makeArrayRef<const Expr *>(TheCall->getArgs(), 616 TheCall->getNumArgs()), 617 NumProtoArgs, /*IsMemberFunction=*/false, 618 TheCall->getRParenLoc(), 619 TheCall->getCallee()->getSourceRange(), CallType); 620 621 return false; 622} 623 624ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult, 625 AtomicExpr::AtomicOp Op) { 626 CallExpr *TheCall = cast<CallExpr>(TheCallResult.get()); 627 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 628 629 // All these operations take one of the following forms: 630 enum { 631 // C __c11_atomic_init(A *, C) 632 Init, 633 // C __c11_atomic_load(A *, int) 634 Load, 635 // void __atomic_load(A *, CP, int) 636 Copy, 637 // C __c11_atomic_add(A *, M, int) 638 Arithmetic, 639 // C __atomic_exchange_n(A *, CP, int) 640 Xchg, 641 // void __atomic_exchange(A *, C *, CP, int) 642 GNUXchg, 643 // bool __c11_atomic_compare_exchange_strong(A *, C *, CP, int, int) 644 C11CmpXchg, 645 // bool __atomic_compare_exchange(A *, C *, CP, bool, int, int) 646 GNUCmpXchg 647 } Form = Init; 648 const unsigned NumArgs[] = { 2, 2, 3, 3, 3, 4, 5, 6 }; 649 const unsigned NumVals[] = { 1, 0, 1, 1, 1, 2, 2, 3 }; 650 // where: 651 // C is an appropriate type, 652 // A is volatile _Atomic(C) for __c11 builtins and is C for GNU builtins, 653 // CP is C for __c11 builtins and GNU _n builtins and is C * otherwise, 654 // M is C if C is an integer, and ptrdiff_t if C is a pointer, and 655 // the int parameters are for orderings. 656 657 assert(AtomicExpr::AO__c11_atomic_init == 0 && 658 AtomicExpr::AO__c11_atomic_fetch_xor + 1 == AtomicExpr::AO__atomic_load 659 && "need to update code for modified C11 atomics"); 660 bool IsC11 = Op >= AtomicExpr::AO__c11_atomic_init && 661 Op <= AtomicExpr::AO__c11_atomic_fetch_xor; 662 bool IsN = Op == AtomicExpr::AO__atomic_load_n || 663 Op == AtomicExpr::AO__atomic_store_n || 664 Op == AtomicExpr::AO__atomic_exchange_n || 665 Op == AtomicExpr::AO__atomic_compare_exchange_n; 666 bool IsAddSub = false; 667 668 switch (Op) { 669 case AtomicExpr::AO__c11_atomic_init: 670 Form = Init; 671 break; 672 673 case AtomicExpr::AO__c11_atomic_load: 674 case AtomicExpr::AO__atomic_load_n: 675 Form = Load; 676 break; 677 678 case AtomicExpr::AO__c11_atomic_store: 679 case AtomicExpr::AO__atomic_load: 680 case AtomicExpr::AO__atomic_store: 681 case AtomicExpr::AO__atomic_store_n: 682 Form = Copy; 683 break; 684 685 case AtomicExpr::AO__c11_atomic_fetch_add: 686 case AtomicExpr::AO__c11_atomic_fetch_sub: 687 case AtomicExpr::AO__atomic_fetch_add: 688 case AtomicExpr::AO__atomic_fetch_sub: 689 case AtomicExpr::AO__atomic_add_fetch: 690 case AtomicExpr::AO__atomic_sub_fetch: 691 IsAddSub = true; 692 // Fall through. 693 case AtomicExpr::AO__c11_atomic_fetch_and: 694 case AtomicExpr::AO__c11_atomic_fetch_or: 695 case AtomicExpr::AO__c11_atomic_fetch_xor: 696 case AtomicExpr::AO__atomic_fetch_and: 697 case AtomicExpr::AO__atomic_fetch_or: 698 case AtomicExpr::AO__atomic_fetch_xor: 699 case AtomicExpr::AO__atomic_fetch_nand: 700 case AtomicExpr::AO__atomic_and_fetch: 701 case AtomicExpr::AO__atomic_or_fetch: 702 case AtomicExpr::AO__atomic_xor_fetch: 703 case AtomicExpr::AO__atomic_nand_fetch: 704 Form = Arithmetic; 705 break; 706 707 case AtomicExpr::AO__c11_atomic_exchange: 708 case AtomicExpr::AO__atomic_exchange_n: 709 Form = Xchg; 710 break; 711 712 case AtomicExpr::AO__atomic_exchange: 713 Form = GNUXchg; 714 break; 715 716 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 717 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 718 Form = C11CmpXchg; 719 break; 720 721 case AtomicExpr::AO__atomic_compare_exchange: 722 case AtomicExpr::AO__atomic_compare_exchange_n: 723 Form = GNUCmpXchg; 724 break; 725 } 726 727 // Check we have the right number of arguments. 728 if (TheCall->getNumArgs() < NumArgs[Form]) { 729 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 730 << 0 << NumArgs[Form] << TheCall->getNumArgs() 731 << TheCall->getCallee()->getSourceRange(); 732 return ExprError(); 733 } else if (TheCall->getNumArgs() > NumArgs[Form]) { 734 Diag(TheCall->getArg(NumArgs[Form])->getLocStart(), 735 diag::err_typecheck_call_too_many_args) 736 << 0 << NumArgs[Form] << TheCall->getNumArgs() 737 << TheCall->getCallee()->getSourceRange(); 738 return ExprError(); 739 } 740 741 // Inspect the first argument of the atomic operation. 742 Expr *Ptr = TheCall->getArg(0); 743 Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get(); 744 const PointerType *pointerType = Ptr->getType()->getAs<PointerType>(); 745 if (!pointerType) { 746 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 747 << Ptr->getType() << Ptr->getSourceRange(); 748 return ExprError(); 749 } 750 751 // For a __c11 builtin, this should be a pointer to an _Atomic type. 752 QualType AtomTy = pointerType->getPointeeType(); // 'A' 753 QualType ValType = AtomTy; // 'C' 754 if (IsC11) { 755 if (!AtomTy->isAtomicType()) { 756 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic) 757 << Ptr->getType() << Ptr->getSourceRange(); 758 return ExprError(); 759 } 760 if (AtomTy.isConstQualified()) { 761 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_atomic) 762 << Ptr->getType() << Ptr->getSourceRange(); 763 return ExprError(); 764 } 765 ValType = AtomTy->getAs<AtomicType>()->getValueType(); 766 } 767 768 // For an arithmetic operation, the implied arithmetic must be well-formed. 769 if (Form == Arithmetic) { 770 // gcc does not enforce these rules for GNU atomics, but we do so for sanity. 771 if (IsAddSub && !ValType->isIntegerType() && !ValType->isPointerType()) { 772 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 773 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 774 return ExprError(); 775 } 776 if (!IsAddSub && !ValType->isIntegerType()) { 777 Diag(DRE->getLocStart(), diag::err_atomic_op_bitwise_needs_atomic_int) 778 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 779 return ExprError(); 780 } 781 } else if (IsN && !ValType->isIntegerType() && !ValType->isPointerType()) { 782 // For __atomic_*_n operations, the value type must be a scalar integral or 783 // pointer type which is 1, 2, 4, 8 or 16 bytes in length. 784 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 785 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 786 return ExprError(); 787 } 788 789 if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context)) { 790 // For GNU atomics, require a trivially-copyable type. This is not part of 791 // the GNU atomics specification, but we enforce it for sanity. 792 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_trivial_copy) 793 << Ptr->getType() << Ptr->getSourceRange(); 794 return ExprError(); 795 } 796 797 // FIXME: For any builtin other than a load, the ValType must not be 798 // const-qualified. 799 800 switch (ValType.getObjCLifetime()) { 801 case Qualifiers::OCL_None: 802 case Qualifiers::OCL_ExplicitNone: 803 // okay 804 break; 805 806 case Qualifiers::OCL_Weak: 807 case Qualifiers::OCL_Strong: 808 case Qualifiers::OCL_Autoreleasing: 809 // FIXME: Can this happen? By this point, ValType should be known 810 // to be trivially copyable. 811 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 812 << ValType << Ptr->getSourceRange(); 813 return ExprError(); 814 } 815 816 QualType ResultType = ValType; 817 if (Form == Copy || Form == GNUXchg || Form == Init) 818 ResultType = Context.VoidTy; 819 else if (Form == C11CmpXchg || Form == GNUCmpXchg) 820 ResultType = Context.BoolTy; 821 822 // The type of a parameter passed 'by value'. In the GNU atomics, such 823 // arguments are actually passed as pointers. 824 QualType ByValType = ValType; // 'CP' 825 if (!IsC11 && !IsN) 826 ByValType = Ptr->getType(); 827 828 // The first argument --- the pointer --- has a fixed type; we 829 // deduce the types of the rest of the arguments accordingly. Walk 830 // the remaining arguments, converting them to the deduced value type. 831 for (unsigned i = 1; i != NumArgs[Form]; ++i) { 832 QualType Ty; 833 if (i < NumVals[Form] + 1) { 834 switch (i) { 835 case 1: 836 // The second argument is the non-atomic operand. For arithmetic, this 837 // is always passed by value, and for a compare_exchange it is always 838 // passed by address. For the rest, GNU uses by-address and C11 uses 839 // by-value. 840 assert(Form != Load); 841 if (Form == Init || (Form == Arithmetic && ValType->isIntegerType())) 842 Ty = ValType; 843 else if (Form == Copy || Form == Xchg) 844 Ty = ByValType; 845 else if (Form == Arithmetic) 846 Ty = Context.getPointerDiffType(); 847 else 848 Ty = Context.getPointerType(ValType.getUnqualifiedType()); 849 break; 850 case 2: 851 // The third argument to compare_exchange / GNU exchange is a 852 // (pointer to a) desired value. 853 Ty = ByValType; 854 break; 855 case 3: 856 // The fourth argument to GNU compare_exchange is a 'weak' flag. 857 Ty = Context.BoolTy; 858 break; 859 } 860 } else { 861 // The order(s) are always converted to int. 862 Ty = Context.IntTy; 863 } 864 865 InitializedEntity Entity = 866 InitializedEntity::InitializeParameter(Context, Ty, false); 867 ExprResult Arg = TheCall->getArg(i); 868 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 869 if (Arg.isInvalid()) 870 return true; 871 TheCall->setArg(i, Arg.get()); 872 } 873 874 // Permute the arguments into a 'consistent' order. 875 SmallVector<Expr*, 5> SubExprs; 876 SubExprs.push_back(Ptr); 877 switch (Form) { 878 case Init: 879 // Note, AtomicExpr::getVal1() has a special case for this atomic. 880 SubExprs.push_back(TheCall->getArg(1)); // Val1 881 break; 882 case Load: 883 SubExprs.push_back(TheCall->getArg(1)); // Order 884 break; 885 case Copy: 886 case Arithmetic: 887 case Xchg: 888 SubExprs.push_back(TheCall->getArg(2)); // Order 889 SubExprs.push_back(TheCall->getArg(1)); // Val1 890 break; 891 case GNUXchg: 892 // Note, AtomicExpr::getVal2() has a special case for this atomic. 893 SubExprs.push_back(TheCall->getArg(3)); // Order 894 SubExprs.push_back(TheCall->getArg(1)); // Val1 895 SubExprs.push_back(TheCall->getArg(2)); // Val2 896 break; 897 case C11CmpXchg: 898 SubExprs.push_back(TheCall->getArg(3)); // Order 899 SubExprs.push_back(TheCall->getArg(1)); // Val1 900 SubExprs.push_back(TheCall->getArg(4)); // OrderFail 901 SubExprs.push_back(TheCall->getArg(2)); // Val2 902 break; 903 case GNUCmpXchg: 904 SubExprs.push_back(TheCall->getArg(4)); // Order 905 SubExprs.push_back(TheCall->getArg(1)); // Val1 906 SubExprs.push_back(TheCall->getArg(5)); // OrderFail 907 SubExprs.push_back(TheCall->getArg(2)); // Val2 908 SubExprs.push_back(TheCall->getArg(3)); // Weak 909 break; 910 } 911 912 return Owned(new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(), 913 SubExprs, ResultType, Op, 914 TheCall->getRParenLoc())); 915} 916 917 918/// checkBuiltinArgument - Given a call to a builtin function, perform 919/// normal type-checking on the given argument, updating the call in 920/// place. This is useful when a builtin function requires custom 921/// type-checking for some of its arguments but not necessarily all of 922/// them. 923/// 924/// Returns true on error. 925static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) { 926 FunctionDecl *Fn = E->getDirectCallee(); 927 assert(Fn && "builtin call without direct callee!"); 928 929 ParmVarDecl *Param = Fn->getParamDecl(ArgIndex); 930 InitializedEntity Entity = 931 InitializedEntity::InitializeParameter(S.Context, Param); 932 933 ExprResult Arg = E->getArg(0); 934 Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg); 935 if (Arg.isInvalid()) 936 return true; 937 938 E->setArg(ArgIndex, Arg.take()); 939 return false; 940} 941 942/// SemaBuiltinAtomicOverloaded - We have a call to a function like 943/// __sync_fetch_and_add, which is an overloaded function based on the pointer 944/// type of its first argument. The main ActOnCallExpr routines have already 945/// promoted the types of arguments because all of these calls are prototyped as 946/// void(...). 947/// 948/// This function goes through and does final semantic checking for these 949/// builtins, 950ExprResult 951Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) { 952 CallExpr *TheCall = (CallExpr *)TheCallResult.get(); 953 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 954 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 955 956 // Ensure that we have at least one argument to do type inference from. 957 if (TheCall->getNumArgs() < 1) { 958 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 959 << 0 << 1 << TheCall->getNumArgs() 960 << TheCall->getCallee()->getSourceRange(); 961 return ExprError(); 962 } 963 964 // Inspect the first argument of the atomic builtin. This should always be 965 // a pointer type, whose element is an integral scalar or pointer type. 966 // Because it is a pointer type, we don't have to worry about any implicit 967 // casts here. 968 // FIXME: We don't allow floating point scalars as input. 969 Expr *FirstArg = TheCall->getArg(0); 970 ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg); 971 if (FirstArgResult.isInvalid()) 972 return ExprError(); 973 FirstArg = FirstArgResult.take(); 974 TheCall->setArg(0, FirstArg); 975 976 const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>(); 977 if (!pointerType) { 978 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 979 << FirstArg->getType() << FirstArg->getSourceRange(); 980 return ExprError(); 981 } 982 983 QualType ValType = pointerType->getPointeeType(); 984 if (!ValType->isIntegerType() && !ValType->isAnyPointerType() && 985 !ValType->isBlockPointerType()) { 986 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr) 987 << FirstArg->getType() << FirstArg->getSourceRange(); 988 return ExprError(); 989 } 990 991 switch (ValType.getObjCLifetime()) { 992 case Qualifiers::OCL_None: 993 case Qualifiers::OCL_ExplicitNone: 994 // okay 995 break; 996 997 case Qualifiers::OCL_Weak: 998 case Qualifiers::OCL_Strong: 999 case Qualifiers::OCL_Autoreleasing: 1000 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 1001 << ValType << FirstArg->getSourceRange(); 1002 return ExprError(); 1003 } 1004 1005 // Strip any qualifiers off ValType. 1006 ValType = ValType.getUnqualifiedType(); 1007 1008 // The majority of builtins return a value, but a few have special return 1009 // types, so allow them to override appropriately below. 1010 QualType ResultType = ValType; 1011 1012 // We need to figure out which concrete builtin this maps onto. For example, 1013 // __sync_fetch_and_add with a 2 byte object turns into 1014 // __sync_fetch_and_add_2. 1015#define BUILTIN_ROW(x) \ 1016 { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \ 1017 Builtin::BI##x##_8, Builtin::BI##x##_16 } 1018 1019 static const unsigned BuiltinIndices[][5] = { 1020 BUILTIN_ROW(__sync_fetch_and_add), 1021 BUILTIN_ROW(__sync_fetch_and_sub), 1022 BUILTIN_ROW(__sync_fetch_and_or), 1023 BUILTIN_ROW(__sync_fetch_and_and), 1024 BUILTIN_ROW(__sync_fetch_and_xor), 1025 1026 BUILTIN_ROW(__sync_add_and_fetch), 1027 BUILTIN_ROW(__sync_sub_and_fetch), 1028 BUILTIN_ROW(__sync_and_and_fetch), 1029 BUILTIN_ROW(__sync_or_and_fetch), 1030 BUILTIN_ROW(__sync_xor_and_fetch), 1031 1032 BUILTIN_ROW(__sync_val_compare_and_swap), 1033 BUILTIN_ROW(__sync_bool_compare_and_swap), 1034 BUILTIN_ROW(__sync_lock_test_and_set), 1035 BUILTIN_ROW(__sync_lock_release), 1036 BUILTIN_ROW(__sync_swap) 1037 }; 1038#undef BUILTIN_ROW 1039 1040 // Determine the index of the size. 1041 unsigned SizeIndex; 1042 switch (Context.getTypeSizeInChars(ValType).getQuantity()) { 1043 case 1: SizeIndex = 0; break; 1044 case 2: SizeIndex = 1; break; 1045 case 4: SizeIndex = 2; break; 1046 case 8: SizeIndex = 3; break; 1047 case 16: SizeIndex = 4; break; 1048 default: 1049 Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size) 1050 << FirstArg->getType() << FirstArg->getSourceRange(); 1051 return ExprError(); 1052 } 1053 1054 // Each of these builtins has one pointer argument, followed by some number of 1055 // values (0, 1 or 2) followed by a potentially empty varags list of stuff 1056 // that we ignore. Find out which row of BuiltinIndices to read from as well 1057 // as the number of fixed args. 1058 unsigned BuiltinID = FDecl->getBuiltinID(); 1059 unsigned BuiltinIndex, NumFixed = 1; 1060 switch (BuiltinID) { 1061 default: llvm_unreachable("Unknown overloaded atomic builtin!"); 1062 case Builtin::BI__sync_fetch_and_add: 1063 case Builtin::BI__sync_fetch_and_add_1: 1064 case Builtin::BI__sync_fetch_and_add_2: 1065 case Builtin::BI__sync_fetch_and_add_4: 1066 case Builtin::BI__sync_fetch_and_add_8: 1067 case Builtin::BI__sync_fetch_and_add_16: 1068 BuiltinIndex = 0; 1069 break; 1070 1071 case Builtin::BI__sync_fetch_and_sub: 1072 case Builtin::BI__sync_fetch_and_sub_1: 1073 case Builtin::BI__sync_fetch_and_sub_2: 1074 case Builtin::BI__sync_fetch_and_sub_4: 1075 case Builtin::BI__sync_fetch_and_sub_8: 1076 case Builtin::BI__sync_fetch_and_sub_16: 1077 BuiltinIndex = 1; 1078 break; 1079 1080 case Builtin::BI__sync_fetch_and_or: 1081 case Builtin::BI__sync_fetch_and_or_1: 1082 case Builtin::BI__sync_fetch_and_or_2: 1083 case Builtin::BI__sync_fetch_and_or_4: 1084 case Builtin::BI__sync_fetch_and_or_8: 1085 case Builtin::BI__sync_fetch_and_or_16: 1086 BuiltinIndex = 2; 1087 break; 1088 1089 case Builtin::BI__sync_fetch_and_and: 1090 case Builtin::BI__sync_fetch_and_and_1: 1091 case Builtin::BI__sync_fetch_and_and_2: 1092 case Builtin::BI__sync_fetch_and_and_4: 1093 case Builtin::BI__sync_fetch_and_and_8: 1094 case Builtin::BI__sync_fetch_and_and_16: 1095 BuiltinIndex = 3; 1096 break; 1097 1098 case Builtin::BI__sync_fetch_and_xor: 1099 case Builtin::BI__sync_fetch_and_xor_1: 1100 case Builtin::BI__sync_fetch_and_xor_2: 1101 case Builtin::BI__sync_fetch_and_xor_4: 1102 case Builtin::BI__sync_fetch_and_xor_8: 1103 case Builtin::BI__sync_fetch_and_xor_16: 1104 BuiltinIndex = 4; 1105 break; 1106 1107 case Builtin::BI__sync_add_and_fetch: 1108 case Builtin::BI__sync_add_and_fetch_1: 1109 case Builtin::BI__sync_add_and_fetch_2: 1110 case Builtin::BI__sync_add_and_fetch_4: 1111 case Builtin::BI__sync_add_and_fetch_8: 1112 case Builtin::BI__sync_add_and_fetch_16: 1113 BuiltinIndex = 5; 1114 break; 1115 1116 case Builtin::BI__sync_sub_and_fetch: 1117 case Builtin::BI__sync_sub_and_fetch_1: 1118 case Builtin::BI__sync_sub_and_fetch_2: 1119 case Builtin::BI__sync_sub_and_fetch_4: 1120 case Builtin::BI__sync_sub_and_fetch_8: 1121 case Builtin::BI__sync_sub_and_fetch_16: 1122 BuiltinIndex = 6; 1123 break; 1124 1125 case Builtin::BI__sync_and_and_fetch: 1126 case Builtin::BI__sync_and_and_fetch_1: 1127 case Builtin::BI__sync_and_and_fetch_2: 1128 case Builtin::BI__sync_and_and_fetch_4: 1129 case Builtin::BI__sync_and_and_fetch_8: 1130 case Builtin::BI__sync_and_and_fetch_16: 1131 BuiltinIndex = 7; 1132 break; 1133 1134 case Builtin::BI__sync_or_and_fetch: 1135 case Builtin::BI__sync_or_and_fetch_1: 1136 case Builtin::BI__sync_or_and_fetch_2: 1137 case Builtin::BI__sync_or_and_fetch_4: 1138 case Builtin::BI__sync_or_and_fetch_8: 1139 case Builtin::BI__sync_or_and_fetch_16: 1140 BuiltinIndex = 8; 1141 break; 1142 1143 case Builtin::BI__sync_xor_and_fetch: 1144 case Builtin::BI__sync_xor_and_fetch_1: 1145 case Builtin::BI__sync_xor_and_fetch_2: 1146 case Builtin::BI__sync_xor_and_fetch_4: 1147 case Builtin::BI__sync_xor_and_fetch_8: 1148 case Builtin::BI__sync_xor_and_fetch_16: 1149 BuiltinIndex = 9; 1150 break; 1151 1152 case Builtin::BI__sync_val_compare_and_swap: 1153 case Builtin::BI__sync_val_compare_and_swap_1: 1154 case Builtin::BI__sync_val_compare_and_swap_2: 1155 case Builtin::BI__sync_val_compare_and_swap_4: 1156 case Builtin::BI__sync_val_compare_and_swap_8: 1157 case Builtin::BI__sync_val_compare_and_swap_16: 1158 BuiltinIndex = 10; 1159 NumFixed = 2; 1160 break; 1161 1162 case Builtin::BI__sync_bool_compare_and_swap: 1163 case Builtin::BI__sync_bool_compare_and_swap_1: 1164 case Builtin::BI__sync_bool_compare_and_swap_2: 1165 case Builtin::BI__sync_bool_compare_and_swap_4: 1166 case Builtin::BI__sync_bool_compare_and_swap_8: 1167 case Builtin::BI__sync_bool_compare_and_swap_16: 1168 BuiltinIndex = 11; 1169 NumFixed = 2; 1170 ResultType = Context.BoolTy; 1171 break; 1172 1173 case Builtin::BI__sync_lock_test_and_set: 1174 case Builtin::BI__sync_lock_test_and_set_1: 1175 case Builtin::BI__sync_lock_test_and_set_2: 1176 case Builtin::BI__sync_lock_test_and_set_4: 1177 case Builtin::BI__sync_lock_test_and_set_8: 1178 case Builtin::BI__sync_lock_test_and_set_16: 1179 BuiltinIndex = 12; 1180 break; 1181 1182 case Builtin::BI__sync_lock_release: 1183 case Builtin::BI__sync_lock_release_1: 1184 case Builtin::BI__sync_lock_release_2: 1185 case Builtin::BI__sync_lock_release_4: 1186 case Builtin::BI__sync_lock_release_8: 1187 case Builtin::BI__sync_lock_release_16: 1188 BuiltinIndex = 13; 1189 NumFixed = 0; 1190 ResultType = Context.VoidTy; 1191 break; 1192 1193 case Builtin::BI__sync_swap: 1194 case Builtin::BI__sync_swap_1: 1195 case Builtin::BI__sync_swap_2: 1196 case Builtin::BI__sync_swap_4: 1197 case Builtin::BI__sync_swap_8: 1198 case Builtin::BI__sync_swap_16: 1199 BuiltinIndex = 14; 1200 break; 1201 } 1202 1203 // Now that we know how many fixed arguments we expect, first check that we 1204 // have at least that many. 1205 if (TheCall->getNumArgs() < 1+NumFixed) { 1206 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 1207 << 0 << 1+NumFixed << TheCall->getNumArgs() 1208 << TheCall->getCallee()->getSourceRange(); 1209 return ExprError(); 1210 } 1211 1212 // Get the decl for the concrete builtin from this, we can tell what the 1213 // concrete integer type we should convert to is. 1214 unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex]; 1215 const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID); 1216 FunctionDecl *NewBuiltinDecl; 1217 if (NewBuiltinID == BuiltinID) 1218 NewBuiltinDecl = FDecl; 1219 else { 1220 // Perform builtin lookup to avoid redeclaring it. 1221 DeclarationName DN(&Context.Idents.get(NewBuiltinName)); 1222 LookupResult Res(*this, DN, DRE->getLocStart(), LookupOrdinaryName); 1223 LookupName(Res, TUScope, /*AllowBuiltinCreation=*/true); 1224 assert(Res.getFoundDecl()); 1225 NewBuiltinDecl = dyn_cast<FunctionDecl>(Res.getFoundDecl()); 1226 if (NewBuiltinDecl == 0) 1227 return ExprError(); 1228 } 1229 1230 // The first argument --- the pointer --- has a fixed type; we 1231 // deduce the types of the rest of the arguments accordingly. Walk 1232 // the remaining arguments, converting them to the deduced value type. 1233 for (unsigned i = 0; i != NumFixed; ++i) { 1234 ExprResult Arg = TheCall->getArg(i+1); 1235 1236 // GCC does an implicit conversion to the pointer or integer ValType. This 1237 // can fail in some cases (1i -> int**), check for this error case now. 1238 // Initialize the argument. 1239 InitializedEntity Entity = InitializedEntity::InitializeParameter(Context, 1240 ValType, /*consume*/ false); 1241 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 1242 if (Arg.isInvalid()) 1243 return ExprError(); 1244 1245 // Okay, we have something that *can* be converted to the right type. Check 1246 // to see if there is a potentially weird extension going on here. This can 1247 // happen when you do an atomic operation on something like an char* and 1248 // pass in 42. The 42 gets converted to char. This is even more strange 1249 // for things like 45.123 -> char, etc. 1250 // FIXME: Do this check. 1251 TheCall->setArg(i+1, Arg.take()); 1252 } 1253 1254 ASTContext& Context = this->getASTContext(); 1255 1256 // Create a new DeclRefExpr to refer to the new decl. 1257 DeclRefExpr* NewDRE = DeclRefExpr::Create( 1258 Context, 1259 DRE->getQualifierLoc(), 1260 SourceLocation(), 1261 NewBuiltinDecl, 1262 /*enclosing*/ false, 1263 DRE->getLocation(), 1264 Context.BuiltinFnTy, 1265 DRE->getValueKind()); 1266 1267 // Set the callee in the CallExpr. 1268 // FIXME: This loses syntactic information. 1269 QualType CalleePtrTy = Context.getPointerType(NewBuiltinDecl->getType()); 1270 ExprResult PromotedCall = ImpCastExprToType(NewDRE, CalleePtrTy, 1271 CK_BuiltinFnToFnPtr); 1272 TheCall->setCallee(PromotedCall.take()); 1273 1274 // Change the result type of the call to match the original value type. This 1275 // is arbitrary, but the codegen for these builtins ins design to handle it 1276 // gracefully. 1277 TheCall->setType(ResultType); 1278 1279 return TheCallResult; 1280} 1281 1282/// CheckObjCString - Checks that the argument to the builtin 1283/// CFString constructor is correct 1284/// Note: It might also make sense to do the UTF-16 conversion here (would 1285/// simplify the backend). 1286bool Sema::CheckObjCString(Expr *Arg) { 1287 Arg = Arg->IgnoreParenCasts(); 1288 StringLiteral *Literal = dyn_cast<StringLiteral>(Arg); 1289 1290 if (!Literal || !Literal->isAscii()) { 1291 Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant) 1292 << Arg->getSourceRange(); 1293 return true; 1294 } 1295 1296 if (Literal->containsNonAsciiOrNull()) { 1297 StringRef String = Literal->getString(); 1298 unsigned NumBytes = String.size(); 1299 SmallVector<UTF16, 128> ToBuf(NumBytes); 1300 const UTF8 *FromPtr = (const UTF8 *)String.data(); 1301 UTF16 *ToPtr = &ToBuf[0]; 1302 1303 ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, 1304 &ToPtr, ToPtr + NumBytes, 1305 strictConversion); 1306 // Check for conversion failure. 1307 if (Result != conversionOK) 1308 Diag(Arg->getLocStart(), 1309 diag::warn_cfstring_truncated) << Arg->getSourceRange(); 1310 } 1311 return false; 1312} 1313 1314/// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity. 1315/// Emit an error and return true on failure, return false on success. 1316bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) { 1317 Expr *Fn = TheCall->getCallee(); 1318 if (TheCall->getNumArgs() > 2) { 1319 Diag(TheCall->getArg(2)->getLocStart(), 1320 diag::err_typecheck_call_too_many_args) 1321 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1322 << Fn->getSourceRange() 1323 << SourceRange(TheCall->getArg(2)->getLocStart(), 1324 (*(TheCall->arg_end()-1))->getLocEnd()); 1325 return true; 1326 } 1327 1328 if (TheCall->getNumArgs() < 2) { 1329 return Diag(TheCall->getLocEnd(), 1330 diag::err_typecheck_call_too_few_args_at_least) 1331 << 0 /*function call*/ << 2 << TheCall->getNumArgs(); 1332 } 1333 1334 // Type-check the first argument normally. 1335 if (checkBuiltinArgument(*this, TheCall, 0)) 1336 return true; 1337 1338 // Determine whether the current function is variadic or not. 1339 BlockScopeInfo *CurBlock = getCurBlock(); 1340 bool isVariadic; 1341 if (CurBlock) 1342 isVariadic = CurBlock->TheDecl->isVariadic(); 1343 else if (FunctionDecl *FD = getCurFunctionDecl()) 1344 isVariadic = FD->isVariadic(); 1345 else 1346 isVariadic = getCurMethodDecl()->isVariadic(); 1347 1348 if (!isVariadic) { 1349 Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function); 1350 return true; 1351 } 1352 1353 // Verify that the second argument to the builtin is the last argument of the 1354 // current function or method. 1355 bool SecondArgIsLastNamedArgument = false; 1356 const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts(); 1357 1358 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) { 1359 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) { 1360 // FIXME: This isn't correct for methods (results in bogus warning). 1361 // Get the last formal in the current function. 1362 const ParmVarDecl *LastArg; 1363 if (CurBlock) 1364 LastArg = *(CurBlock->TheDecl->param_end()-1); 1365 else if (FunctionDecl *FD = getCurFunctionDecl()) 1366 LastArg = *(FD->param_end()-1); 1367 else 1368 LastArg = *(getCurMethodDecl()->param_end()-1); 1369 SecondArgIsLastNamedArgument = PV == LastArg; 1370 } 1371 } 1372 1373 if (!SecondArgIsLastNamedArgument) 1374 Diag(TheCall->getArg(1)->getLocStart(), 1375 diag::warn_second_parameter_of_va_start_not_last_named_argument); 1376 return false; 1377} 1378 1379/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and 1380/// friends. This is declared to take (...), so we have to check everything. 1381bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) { 1382 if (TheCall->getNumArgs() < 2) 1383 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 1384 << 0 << 2 << TheCall->getNumArgs()/*function call*/; 1385 if (TheCall->getNumArgs() > 2) 1386 return Diag(TheCall->getArg(2)->getLocStart(), 1387 diag::err_typecheck_call_too_many_args) 1388 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1389 << SourceRange(TheCall->getArg(2)->getLocStart(), 1390 (*(TheCall->arg_end()-1))->getLocEnd()); 1391 1392 ExprResult OrigArg0 = TheCall->getArg(0); 1393 ExprResult OrigArg1 = TheCall->getArg(1); 1394 1395 // Do standard promotions between the two arguments, returning their common 1396 // type. 1397 QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false); 1398 if (OrigArg0.isInvalid() || OrigArg1.isInvalid()) 1399 return true; 1400 1401 // Make sure any conversions are pushed back into the call; this is 1402 // type safe since unordered compare builtins are declared as "_Bool 1403 // foo(...)". 1404 TheCall->setArg(0, OrigArg0.get()); 1405 TheCall->setArg(1, OrigArg1.get()); 1406 1407 if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent()) 1408 return false; 1409 1410 // If the common type isn't a real floating type, then the arguments were 1411 // invalid for this operation. 1412 if (Res.isNull() || !Res->isRealFloatingType()) 1413 return Diag(OrigArg0.get()->getLocStart(), 1414 diag::err_typecheck_call_invalid_ordered_compare) 1415 << OrigArg0.get()->getType() << OrigArg1.get()->getType() 1416 << SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd()); 1417 1418 return false; 1419} 1420 1421/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like 1422/// __builtin_isnan and friends. This is declared to take (...), so we have 1423/// to check everything. We expect the last argument to be a floating point 1424/// value. 1425bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) { 1426 if (TheCall->getNumArgs() < NumArgs) 1427 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 1428 << 0 << NumArgs << TheCall->getNumArgs()/*function call*/; 1429 if (TheCall->getNumArgs() > NumArgs) 1430 return Diag(TheCall->getArg(NumArgs)->getLocStart(), 1431 diag::err_typecheck_call_too_many_args) 1432 << 0 /*function call*/ << NumArgs << TheCall->getNumArgs() 1433 << SourceRange(TheCall->getArg(NumArgs)->getLocStart(), 1434 (*(TheCall->arg_end()-1))->getLocEnd()); 1435 1436 Expr *OrigArg = TheCall->getArg(NumArgs-1); 1437 1438 if (OrigArg->isTypeDependent()) 1439 return false; 1440 1441 // This operation requires a non-_Complex floating-point number. 1442 if (!OrigArg->getType()->isRealFloatingType()) 1443 return Diag(OrigArg->getLocStart(), 1444 diag::err_typecheck_call_invalid_unary_fp) 1445 << OrigArg->getType() << OrigArg->getSourceRange(); 1446 1447 // If this is an implicit conversion from float -> double, remove it. 1448 if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) { 1449 Expr *CastArg = Cast->getSubExpr(); 1450 if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) { 1451 assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) && 1452 "promotion from float to double is the only expected cast here"); 1453 Cast->setSubExpr(0); 1454 TheCall->setArg(NumArgs-1, CastArg); 1455 } 1456 } 1457 1458 return false; 1459} 1460 1461/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector. 1462// This is declared to take (...), so we have to check everything. 1463ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) { 1464 if (TheCall->getNumArgs() < 2) 1465 return ExprError(Diag(TheCall->getLocEnd(), 1466 diag::err_typecheck_call_too_few_args_at_least) 1467 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1468 << TheCall->getSourceRange()); 1469 1470 // Determine which of the following types of shufflevector we're checking: 1471 // 1) unary, vector mask: (lhs, mask) 1472 // 2) binary, vector mask: (lhs, rhs, mask) 1473 // 3) binary, scalar mask: (lhs, rhs, index, ..., index) 1474 QualType resType = TheCall->getArg(0)->getType(); 1475 unsigned numElements = 0; 1476 1477 if (!TheCall->getArg(0)->isTypeDependent() && 1478 !TheCall->getArg(1)->isTypeDependent()) { 1479 QualType LHSType = TheCall->getArg(0)->getType(); 1480 QualType RHSType = TheCall->getArg(1)->getType(); 1481 1482 if (!LHSType->isVectorType() || !RHSType->isVectorType()) { 1483 Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector) 1484 << SourceRange(TheCall->getArg(0)->getLocStart(), 1485 TheCall->getArg(1)->getLocEnd()); 1486 return ExprError(); 1487 } 1488 1489 numElements = LHSType->getAs<VectorType>()->getNumElements(); 1490 unsigned numResElements = TheCall->getNumArgs() - 2; 1491 1492 // Check to see if we have a call with 2 vector arguments, the unary shuffle 1493 // with mask. If so, verify that RHS is an integer vector type with the 1494 // same number of elts as lhs. 1495 if (TheCall->getNumArgs() == 2) { 1496 if (!RHSType->hasIntegerRepresentation() || 1497 RHSType->getAs<VectorType>()->getNumElements() != numElements) 1498 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 1499 << SourceRange(TheCall->getArg(1)->getLocStart(), 1500 TheCall->getArg(1)->getLocEnd()); 1501 numResElements = numElements; 1502 } 1503 else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) { 1504 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 1505 << SourceRange(TheCall->getArg(0)->getLocStart(), 1506 TheCall->getArg(1)->getLocEnd()); 1507 return ExprError(); 1508 } else if (numElements != numResElements) { 1509 QualType eltType = LHSType->getAs<VectorType>()->getElementType(); 1510 resType = Context.getVectorType(eltType, numResElements, 1511 VectorType::GenericVector); 1512 } 1513 } 1514 1515 for (unsigned i = 2; i < TheCall->getNumArgs(); i++) { 1516 if (TheCall->getArg(i)->isTypeDependent() || 1517 TheCall->getArg(i)->isValueDependent()) 1518 continue; 1519 1520 llvm::APSInt Result(32); 1521 if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context)) 1522 return ExprError(Diag(TheCall->getLocStart(), 1523 diag::err_shufflevector_nonconstant_argument) 1524 << TheCall->getArg(i)->getSourceRange()); 1525 1526 if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2) 1527 return ExprError(Diag(TheCall->getLocStart(), 1528 diag::err_shufflevector_argument_too_large) 1529 << TheCall->getArg(i)->getSourceRange()); 1530 } 1531 1532 SmallVector<Expr*, 32> exprs; 1533 1534 for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) { 1535 exprs.push_back(TheCall->getArg(i)); 1536 TheCall->setArg(i, 0); 1537 } 1538 1539 return Owned(new (Context) ShuffleVectorExpr(Context, exprs, resType, 1540 TheCall->getCallee()->getLocStart(), 1541 TheCall->getRParenLoc())); 1542} 1543 1544/// SemaBuiltinPrefetch - Handle __builtin_prefetch. 1545// This is declared to take (const void*, ...) and can take two 1546// optional constant int args. 1547bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) { 1548 unsigned NumArgs = TheCall->getNumArgs(); 1549 1550 if (NumArgs > 3) 1551 return Diag(TheCall->getLocEnd(), 1552 diag::err_typecheck_call_too_many_args_at_most) 1553 << 0 /*function call*/ << 3 << NumArgs 1554 << TheCall->getSourceRange(); 1555 1556 // Argument 0 is checked for us and the remaining arguments must be 1557 // constant integers. 1558 for (unsigned i = 1; i != NumArgs; ++i) { 1559 Expr *Arg = TheCall->getArg(i); 1560 1561 // We can't check the value of a dependent argument. 1562 if (Arg->isTypeDependent() || Arg->isValueDependent()) 1563 continue; 1564 1565 llvm::APSInt Result; 1566 if (SemaBuiltinConstantArg(TheCall, i, Result)) 1567 return true; 1568 1569 // FIXME: gcc issues a warning and rewrites these to 0. These 1570 // seems especially odd for the third argument since the default 1571 // is 3. 1572 if (i == 1) { 1573 if (Result.getLimitedValue() > 1) 1574 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1575 << "0" << "1" << Arg->getSourceRange(); 1576 } else { 1577 if (Result.getLimitedValue() > 3) 1578 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1579 << "0" << "3" << Arg->getSourceRange(); 1580 } 1581 } 1582 1583 return false; 1584} 1585 1586/// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr 1587/// TheCall is a constant expression. 1588bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum, 1589 llvm::APSInt &Result) { 1590 Expr *Arg = TheCall->getArg(ArgNum); 1591 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 1592 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 1593 1594 if (Arg->isTypeDependent() || Arg->isValueDependent()) return false; 1595 1596 if (!Arg->isIntegerConstantExpr(Result, Context)) 1597 return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type) 1598 << FDecl->getDeclName() << Arg->getSourceRange(); 1599 1600 return false; 1601} 1602 1603/// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr, 1604/// int type). This simply type checks that type is one of the defined 1605/// constants (0-3). 1606// For compatibility check 0-3, llvm only handles 0 and 2. 1607bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) { 1608 llvm::APSInt Result; 1609 1610 // We can't check the value of a dependent argument. 1611 if (TheCall->getArg(1)->isTypeDependent() || 1612 TheCall->getArg(1)->isValueDependent()) 1613 return false; 1614 1615 // Check constant-ness first. 1616 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 1617 return true; 1618 1619 Expr *Arg = TheCall->getArg(1); 1620 if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) { 1621 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1622 << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 1623 } 1624 1625 return false; 1626} 1627 1628/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val). 1629/// This checks that val is a constant 1. 1630bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) { 1631 Expr *Arg = TheCall->getArg(1); 1632 llvm::APSInt Result; 1633 1634 // TODO: This is less than ideal. Overload this to take a value. 1635 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 1636 return true; 1637 1638 if (Result != 1) 1639 return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val) 1640 << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 1641 1642 return false; 1643} 1644 1645// Determine if an expression is a string literal or constant string. 1646// If this function returns false on the arguments to a function expecting a 1647// format string, we will usually need to emit a warning. 1648// True string literals are then checked by CheckFormatString. 1649Sema::StringLiteralCheckType 1650Sema::checkFormatStringExpr(const Expr *E, ArrayRef<const Expr *> Args, 1651 bool HasVAListArg, 1652 unsigned format_idx, unsigned firstDataArg, 1653 FormatStringType Type, VariadicCallType CallType, 1654 bool inFunctionCall) { 1655 tryAgain: 1656 if (E->isTypeDependent() || E->isValueDependent()) 1657 return SLCT_NotALiteral; 1658 1659 E = E->IgnoreParenCasts(); 1660 1661 if (E->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull)) 1662 // Technically -Wformat-nonliteral does not warn about this case. 1663 // The behavior of printf and friends in this case is implementation 1664 // dependent. Ideally if the format string cannot be null then 1665 // it should have a 'nonnull' attribute in the function prototype. 1666 return SLCT_CheckedLiteral; 1667 1668 switch (E->getStmtClass()) { 1669 case Stmt::BinaryConditionalOperatorClass: 1670 case Stmt::ConditionalOperatorClass: { 1671 // The expression is a literal if both sub-expressions were, and it was 1672 // completely checked only if both sub-expressions were checked. 1673 const AbstractConditionalOperator *C = 1674 cast<AbstractConditionalOperator>(E); 1675 StringLiteralCheckType Left = 1676 checkFormatStringExpr(C->getTrueExpr(), Args, 1677 HasVAListArg, format_idx, firstDataArg, 1678 Type, CallType, inFunctionCall); 1679 if (Left == SLCT_NotALiteral) 1680 return SLCT_NotALiteral; 1681 StringLiteralCheckType Right = 1682 checkFormatStringExpr(C->getFalseExpr(), Args, 1683 HasVAListArg, format_idx, firstDataArg, 1684 Type, CallType, inFunctionCall); 1685 return Left < Right ? Left : Right; 1686 } 1687 1688 case Stmt::ImplicitCastExprClass: { 1689 E = cast<ImplicitCastExpr>(E)->getSubExpr(); 1690 goto tryAgain; 1691 } 1692 1693 case Stmt::OpaqueValueExprClass: 1694 if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) { 1695 E = src; 1696 goto tryAgain; 1697 } 1698 return SLCT_NotALiteral; 1699 1700 case Stmt::PredefinedExprClass: 1701 // While __func__, etc., are technically not string literals, they 1702 // cannot contain format specifiers and thus are not a security 1703 // liability. 1704 return SLCT_UncheckedLiteral; 1705 1706 case Stmt::DeclRefExprClass: { 1707 const DeclRefExpr *DR = cast<DeclRefExpr>(E); 1708 1709 // As an exception, do not flag errors for variables binding to 1710 // const string literals. 1711 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) { 1712 bool isConstant = false; 1713 QualType T = DR->getType(); 1714 1715 if (const ArrayType *AT = Context.getAsArrayType(T)) { 1716 isConstant = AT->getElementType().isConstant(Context); 1717 } else if (const PointerType *PT = T->getAs<PointerType>()) { 1718 isConstant = T.isConstant(Context) && 1719 PT->getPointeeType().isConstant(Context); 1720 } else if (T->isObjCObjectPointerType()) { 1721 // In ObjC, there is usually no "const ObjectPointer" type, 1722 // so don't check if the pointee type is constant. 1723 isConstant = T.isConstant(Context); 1724 } 1725 1726 if (isConstant) { 1727 if (const Expr *Init = VD->getAnyInitializer()) { 1728 // Look through initializers like const char c[] = { "foo" } 1729 if (const InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) { 1730 if (InitList->isStringLiteralInit()) 1731 Init = InitList->getInit(0)->IgnoreParenImpCasts(); 1732 } 1733 return checkFormatStringExpr(Init, Args, 1734 HasVAListArg, format_idx, 1735 firstDataArg, Type, CallType, 1736 /*inFunctionCall*/false); 1737 } 1738 } 1739 1740 // For vprintf* functions (i.e., HasVAListArg==true), we add a 1741 // special check to see if the format string is a function parameter 1742 // of the function calling the printf function. If the function 1743 // has an attribute indicating it is a printf-like function, then we 1744 // should suppress warnings concerning non-literals being used in a call 1745 // to a vprintf function. For example: 1746 // 1747 // void 1748 // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){ 1749 // va_list ap; 1750 // va_start(ap, fmt); 1751 // vprintf(fmt, ap); // Do NOT emit a warning about "fmt". 1752 // ... 1753 // 1754 if (HasVAListArg) { 1755 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(VD)) { 1756 if (const NamedDecl *ND = dyn_cast<NamedDecl>(PV->getDeclContext())) { 1757 int PVIndex = PV->getFunctionScopeIndex() + 1; 1758 for (specific_attr_iterator<FormatAttr> 1759 i = ND->specific_attr_begin<FormatAttr>(), 1760 e = ND->specific_attr_end<FormatAttr>(); i != e ; ++i) { 1761 FormatAttr *PVFormat = *i; 1762 // adjust for implicit parameter 1763 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 1764 if (MD->isInstance()) 1765 ++PVIndex; 1766 // We also check if the formats are compatible. 1767 // We can't pass a 'scanf' string to a 'printf' function. 1768 if (PVIndex == PVFormat->getFormatIdx() && 1769 Type == GetFormatStringType(PVFormat)) 1770 return SLCT_UncheckedLiteral; 1771 } 1772 } 1773 } 1774 } 1775 } 1776 1777 return SLCT_NotALiteral; 1778 } 1779 1780 case Stmt::CallExprClass: 1781 case Stmt::CXXMemberCallExprClass: { 1782 const CallExpr *CE = cast<CallExpr>(E); 1783 if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) { 1784 if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) { 1785 unsigned ArgIndex = FA->getFormatIdx(); 1786 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 1787 if (MD->isInstance()) 1788 --ArgIndex; 1789 const Expr *Arg = CE->getArg(ArgIndex - 1); 1790 1791 return checkFormatStringExpr(Arg, Args, 1792 HasVAListArg, format_idx, firstDataArg, 1793 Type, CallType, inFunctionCall); 1794 } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) { 1795 unsigned BuiltinID = FD->getBuiltinID(); 1796 if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString || 1797 BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) { 1798 const Expr *Arg = CE->getArg(0); 1799 return checkFormatStringExpr(Arg, Args, 1800 HasVAListArg, format_idx, 1801 firstDataArg, Type, CallType, 1802 inFunctionCall); 1803 } 1804 } 1805 } 1806 1807 return SLCT_NotALiteral; 1808 } 1809 case Stmt::ObjCStringLiteralClass: 1810 case Stmt::StringLiteralClass: { 1811 const StringLiteral *StrE = NULL; 1812 1813 if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E)) 1814 StrE = ObjCFExpr->getString(); 1815 else 1816 StrE = cast<StringLiteral>(E); 1817 1818 if (StrE) { 1819 CheckFormatString(StrE, E, Args, HasVAListArg, format_idx, 1820 firstDataArg, Type, inFunctionCall, CallType); 1821 return SLCT_CheckedLiteral; 1822 } 1823 1824 return SLCT_NotALiteral; 1825 } 1826 1827 default: 1828 return SLCT_NotALiteral; 1829 } 1830} 1831 1832void 1833Sema::CheckNonNullArguments(const NonNullAttr *NonNull, 1834 const Expr * const *ExprArgs, 1835 SourceLocation CallSiteLoc) { 1836 for (NonNullAttr::args_iterator i = NonNull->args_begin(), 1837 e = NonNull->args_end(); 1838 i != e; ++i) { 1839 const Expr *ArgExpr = ExprArgs[*i]; 1840 1841 // As a special case, transparent unions initialized with zero are 1842 // considered null for the purposes of the nonnull attribute. 1843 if (const RecordType *UT = ArgExpr->getType()->getAsUnionType()) { 1844 if (UT->getDecl()->hasAttr<TransparentUnionAttr>()) 1845 if (const CompoundLiteralExpr *CLE = 1846 dyn_cast<CompoundLiteralExpr>(ArgExpr)) 1847 if (const InitListExpr *ILE = 1848 dyn_cast<InitListExpr>(CLE->getInitializer())) 1849 ArgExpr = ILE->getInit(0); 1850 } 1851 1852 bool Result; 1853 if (ArgExpr->EvaluateAsBooleanCondition(Result, Context) && !Result) 1854 Diag(CallSiteLoc, diag::warn_null_arg) << ArgExpr->getSourceRange(); 1855 } 1856} 1857 1858Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) { 1859 return llvm::StringSwitch<FormatStringType>(Format->getType()) 1860 .Case("scanf", FST_Scanf) 1861 .Cases("printf", "printf0", FST_Printf) 1862 .Cases("NSString", "CFString", FST_NSString) 1863 .Case("strftime", FST_Strftime) 1864 .Case("strfmon", FST_Strfmon) 1865 .Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf) 1866 .Default(FST_Unknown); 1867} 1868 1869/// CheckFormatArguments - Check calls to printf and scanf (and similar 1870/// functions) for correct use of format strings. 1871/// Returns true if a format string has been fully checked. 1872bool Sema::CheckFormatArguments(const FormatAttr *Format, 1873 ArrayRef<const Expr *> Args, 1874 bool IsCXXMember, 1875 VariadicCallType CallType, 1876 SourceLocation Loc, SourceRange Range) { 1877 FormatStringInfo FSI; 1878 if (getFormatStringInfo(Format, IsCXXMember, &FSI)) 1879 return CheckFormatArguments(Args, FSI.HasVAListArg, FSI.FormatIdx, 1880 FSI.FirstDataArg, GetFormatStringType(Format), 1881 CallType, Loc, Range); 1882 return false; 1883} 1884 1885bool Sema::CheckFormatArguments(ArrayRef<const Expr *> Args, 1886 bool HasVAListArg, unsigned format_idx, 1887 unsigned firstDataArg, FormatStringType Type, 1888 VariadicCallType CallType, 1889 SourceLocation Loc, SourceRange Range) { 1890 // CHECK: printf/scanf-like function is called with no format string. 1891 if (format_idx >= Args.size()) { 1892 Diag(Loc, diag::warn_missing_format_string) << Range; 1893 return false; 1894 } 1895 1896 const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts(); 1897 1898 // CHECK: format string is not a string literal. 1899 // 1900 // Dynamically generated format strings are difficult to 1901 // automatically vet at compile time. Requiring that format strings 1902 // are string literals: (1) permits the checking of format strings by 1903 // the compiler and thereby (2) can practically remove the source of 1904 // many format string exploits. 1905 1906 // Format string can be either ObjC string (e.g. @"%d") or 1907 // C string (e.g. "%d") 1908 // ObjC string uses the same format specifiers as C string, so we can use 1909 // the same format string checking logic for both ObjC and C strings. 1910 StringLiteralCheckType CT = 1911 checkFormatStringExpr(OrigFormatExpr, Args, HasVAListArg, 1912 format_idx, firstDataArg, Type, CallType); 1913 if (CT != SLCT_NotALiteral) 1914 // Literal format string found, check done! 1915 return CT == SLCT_CheckedLiteral; 1916 1917 // Strftime is particular as it always uses a single 'time' argument, 1918 // so it is safe to pass a non-literal string. 1919 if (Type == FST_Strftime) 1920 return false; 1921 1922 // Do not emit diag when the string param is a macro expansion and the 1923 // format is either NSString or CFString. This is a hack to prevent 1924 // diag when using the NSLocalizedString and CFCopyLocalizedString macros 1925 // which are usually used in place of NS and CF string literals. 1926 if (Type == FST_NSString && 1927 SourceMgr.isInSystemMacro(Args[format_idx]->getLocStart())) 1928 return false; 1929 1930 // If there are no arguments specified, warn with -Wformat-security, otherwise 1931 // warn only with -Wformat-nonliteral. 1932 if (Args.size() == format_idx+1) 1933 Diag(Args[format_idx]->getLocStart(), 1934 diag::warn_format_nonliteral_noargs) 1935 << OrigFormatExpr->getSourceRange(); 1936 else 1937 Diag(Args[format_idx]->getLocStart(), 1938 diag::warn_format_nonliteral) 1939 << OrigFormatExpr->getSourceRange(); 1940 return false; 1941} 1942 1943namespace { 1944class CheckFormatHandler : public analyze_format_string::FormatStringHandler { 1945protected: 1946 Sema &S; 1947 const StringLiteral *FExpr; 1948 const Expr *OrigFormatExpr; 1949 const unsigned FirstDataArg; 1950 const unsigned NumDataArgs; 1951 const char *Beg; // Start of format string. 1952 const bool HasVAListArg; 1953 ArrayRef<const Expr *> Args; 1954 unsigned FormatIdx; 1955 llvm::BitVector CoveredArgs; 1956 bool usesPositionalArgs; 1957 bool atFirstArg; 1958 bool inFunctionCall; 1959 Sema::VariadicCallType CallType; 1960public: 1961 CheckFormatHandler(Sema &s, const StringLiteral *fexpr, 1962 const Expr *origFormatExpr, unsigned firstDataArg, 1963 unsigned numDataArgs, const char *beg, bool hasVAListArg, 1964 ArrayRef<const Expr *> Args, 1965 unsigned formatIdx, bool inFunctionCall, 1966 Sema::VariadicCallType callType) 1967 : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr), 1968 FirstDataArg(firstDataArg), NumDataArgs(numDataArgs), 1969 Beg(beg), HasVAListArg(hasVAListArg), 1970 Args(Args), FormatIdx(formatIdx), 1971 usesPositionalArgs(false), atFirstArg(true), 1972 inFunctionCall(inFunctionCall), CallType(callType) { 1973 CoveredArgs.resize(numDataArgs); 1974 CoveredArgs.reset(); 1975 } 1976 1977 void DoneProcessing(); 1978 1979 void HandleIncompleteSpecifier(const char *startSpecifier, 1980 unsigned specifierLen); 1981 1982 void HandleInvalidLengthModifier( 1983 const analyze_format_string::FormatSpecifier &FS, 1984 const analyze_format_string::ConversionSpecifier &CS, 1985 const char *startSpecifier, unsigned specifierLen, unsigned DiagID); 1986 1987 void HandleNonStandardLengthModifier( 1988 const analyze_format_string::FormatSpecifier &FS, 1989 const char *startSpecifier, unsigned specifierLen); 1990 1991 void HandleNonStandardConversionSpecifier( 1992 const analyze_format_string::ConversionSpecifier &CS, 1993 const char *startSpecifier, unsigned specifierLen); 1994 1995 virtual void HandlePosition(const char *startPos, unsigned posLen); 1996 1997 virtual void HandleInvalidPosition(const char *startSpecifier, 1998 unsigned specifierLen, 1999 analyze_format_string::PositionContext p); 2000 2001 virtual void HandleZeroPosition(const char *startPos, unsigned posLen); 2002 2003 void HandleNullChar(const char *nullCharacter); 2004 2005 template <typename Range> 2006 static void EmitFormatDiagnostic(Sema &S, bool inFunctionCall, 2007 const Expr *ArgumentExpr, 2008 PartialDiagnostic PDiag, 2009 SourceLocation StringLoc, 2010 bool IsStringLocation, Range StringRange, 2011 ArrayRef<FixItHint> Fixit = None); 2012 2013protected: 2014 bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc, 2015 const char *startSpec, 2016 unsigned specifierLen, 2017 const char *csStart, unsigned csLen); 2018 2019 void HandlePositionalNonpositionalArgs(SourceLocation Loc, 2020 const char *startSpec, 2021 unsigned specifierLen); 2022 2023 SourceRange getFormatStringRange(); 2024 CharSourceRange getSpecifierRange(const char *startSpecifier, 2025 unsigned specifierLen); 2026 SourceLocation getLocationOfByte(const char *x); 2027 2028 const Expr *getDataArg(unsigned i) const; 2029 2030 bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS, 2031 const analyze_format_string::ConversionSpecifier &CS, 2032 const char *startSpecifier, unsigned specifierLen, 2033 unsigned argIndex); 2034 2035 template <typename Range> 2036 void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc, 2037 bool IsStringLocation, Range StringRange, 2038 ArrayRef<FixItHint> Fixit = None); 2039 2040 void CheckPositionalAndNonpositionalArgs( 2041 const analyze_format_string::FormatSpecifier *FS); 2042}; 2043} 2044 2045SourceRange CheckFormatHandler::getFormatStringRange() { 2046 return OrigFormatExpr->getSourceRange(); 2047} 2048 2049CharSourceRange CheckFormatHandler:: 2050getSpecifierRange(const char *startSpecifier, unsigned specifierLen) { 2051 SourceLocation Start = getLocationOfByte(startSpecifier); 2052 SourceLocation End = getLocationOfByte(startSpecifier + specifierLen - 1); 2053 2054 // Advance the end SourceLocation by one due to half-open ranges. 2055 End = End.getLocWithOffset(1); 2056 2057 return CharSourceRange::getCharRange(Start, End); 2058} 2059 2060SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) { 2061 return S.getLocationOfStringLiteralByte(FExpr, x - Beg); 2062} 2063 2064void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier, 2065 unsigned specifierLen){ 2066 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier), 2067 getLocationOfByte(startSpecifier), 2068 /*IsStringLocation*/true, 2069 getSpecifierRange(startSpecifier, specifierLen)); 2070} 2071 2072void CheckFormatHandler::HandleInvalidLengthModifier( 2073 const analyze_format_string::FormatSpecifier &FS, 2074 const analyze_format_string::ConversionSpecifier &CS, 2075 const char *startSpecifier, unsigned specifierLen, unsigned DiagID) { 2076 using namespace analyze_format_string; 2077 2078 const LengthModifier &LM = FS.getLengthModifier(); 2079 CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength()); 2080 2081 // See if we know how to fix this length modifier. 2082 Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier(); 2083 if (FixedLM) { 2084 EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(), 2085 getLocationOfByte(LM.getStart()), 2086 /*IsStringLocation*/true, 2087 getSpecifierRange(startSpecifier, specifierLen)); 2088 2089 S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier) 2090 << FixedLM->toString() 2091 << FixItHint::CreateReplacement(LMRange, FixedLM->toString()); 2092 2093 } else { 2094 FixItHint Hint; 2095 if (DiagID == diag::warn_format_nonsensical_length) 2096 Hint = FixItHint::CreateRemoval(LMRange); 2097 2098 EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(), 2099 getLocationOfByte(LM.getStart()), 2100 /*IsStringLocation*/true, 2101 getSpecifierRange(startSpecifier, specifierLen), 2102 Hint); 2103 } 2104} 2105 2106void CheckFormatHandler::HandleNonStandardLengthModifier( 2107 const analyze_format_string::FormatSpecifier &FS, 2108 const char *startSpecifier, unsigned specifierLen) { 2109 using namespace analyze_format_string; 2110 2111 const LengthModifier &LM = FS.getLengthModifier(); 2112 CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength()); 2113 2114 // See if we know how to fix this length modifier. 2115 Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier(); 2116 if (FixedLM) { 2117 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2118 << LM.toString() << 0, 2119 getLocationOfByte(LM.getStart()), 2120 /*IsStringLocation*/true, 2121 getSpecifierRange(startSpecifier, specifierLen)); 2122 2123 S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier) 2124 << FixedLM->toString() 2125 << FixItHint::CreateReplacement(LMRange, FixedLM->toString()); 2126 2127 } else { 2128 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2129 << LM.toString() << 0, 2130 getLocationOfByte(LM.getStart()), 2131 /*IsStringLocation*/true, 2132 getSpecifierRange(startSpecifier, specifierLen)); 2133 } 2134} 2135 2136void CheckFormatHandler::HandleNonStandardConversionSpecifier( 2137 const analyze_format_string::ConversionSpecifier &CS, 2138 const char *startSpecifier, unsigned specifierLen) { 2139 using namespace analyze_format_string; 2140 2141 // See if we know how to fix this conversion specifier. 2142 Optional<ConversionSpecifier> FixedCS = CS.getStandardSpecifier(); 2143 if (FixedCS) { 2144 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2145 << CS.toString() << /*conversion specifier*/1, 2146 getLocationOfByte(CS.getStart()), 2147 /*IsStringLocation*/true, 2148 getSpecifierRange(startSpecifier, specifierLen)); 2149 2150 CharSourceRange CSRange = getSpecifierRange(CS.getStart(), CS.getLength()); 2151 S.Diag(getLocationOfByte(CS.getStart()), diag::note_format_fix_specifier) 2152 << FixedCS->toString() 2153 << FixItHint::CreateReplacement(CSRange, FixedCS->toString()); 2154 } else { 2155 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2156 << CS.toString() << /*conversion specifier*/1, 2157 getLocationOfByte(CS.getStart()), 2158 /*IsStringLocation*/true, 2159 getSpecifierRange(startSpecifier, specifierLen)); 2160 } 2161} 2162 2163void CheckFormatHandler::HandlePosition(const char *startPos, 2164 unsigned posLen) { 2165 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg), 2166 getLocationOfByte(startPos), 2167 /*IsStringLocation*/true, 2168 getSpecifierRange(startPos, posLen)); 2169} 2170 2171void 2172CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen, 2173 analyze_format_string::PositionContext p) { 2174 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier) 2175 << (unsigned) p, 2176 getLocationOfByte(startPos), /*IsStringLocation*/true, 2177 getSpecifierRange(startPos, posLen)); 2178} 2179 2180void CheckFormatHandler::HandleZeroPosition(const char *startPos, 2181 unsigned posLen) { 2182 EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier), 2183 getLocationOfByte(startPos), 2184 /*IsStringLocation*/true, 2185 getSpecifierRange(startPos, posLen)); 2186} 2187 2188void CheckFormatHandler::HandleNullChar(const char *nullCharacter) { 2189 if (!isa<ObjCStringLiteral>(OrigFormatExpr)) { 2190 // The presence of a null character is likely an error. 2191 EmitFormatDiagnostic( 2192 S.PDiag(diag::warn_printf_format_string_contains_null_char), 2193 getLocationOfByte(nullCharacter), /*IsStringLocation*/true, 2194 getFormatStringRange()); 2195 } 2196} 2197 2198// Note that this may return NULL if there was an error parsing or building 2199// one of the argument expressions. 2200const Expr *CheckFormatHandler::getDataArg(unsigned i) const { 2201 return Args[FirstDataArg + i]; 2202} 2203 2204void CheckFormatHandler::DoneProcessing() { 2205 // Does the number of data arguments exceed the number of 2206 // format conversions in the format string? 2207 if (!HasVAListArg) { 2208 // Find any arguments that weren't covered. 2209 CoveredArgs.flip(); 2210 signed notCoveredArg = CoveredArgs.find_first(); 2211 if (notCoveredArg >= 0) { 2212 assert((unsigned)notCoveredArg < NumDataArgs); 2213 if (const Expr *E = getDataArg((unsigned) notCoveredArg)) { 2214 SourceLocation Loc = E->getLocStart(); 2215 if (!S.getSourceManager().isInSystemMacro(Loc)) { 2216 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_data_arg_not_used), 2217 Loc, /*IsStringLocation*/false, 2218 getFormatStringRange()); 2219 } 2220 } 2221 } 2222 } 2223} 2224 2225bool 2226CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex, 2227 SourceLocation Loc, 2228 const char *startSpec, 2229 unsigned specifierLen, 2230 const char *csStart, 2231 unsigned csLen) { 2232 2233 bool keepGoing = true; 2234 if (argIndex < NumDataArgs) { 2235 // Consider the argument coverered, even though the specifier doesn't 2236 // make sense. 2237 CoveredArgs.set(argIndex); 2238 } 2239 else { 2240 // If argIndex exceeds the number of data arguments we 2241 // don't issue a warning because that is just a cascade of warnings (and 2242 // they may have intended '%%' anyway). We don't want to continue processing 2243 // the format string after this point, however, as we will like just get 2244 // gibberish when trying to match arguments. 2245 keepGoing = false; 2246 } 2247 2248 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion) 2249 << StringRef(csStart, csLen), 2250 Loc, /*IsStringLocation*/true, 2251 getSpecifierRange(startSpec, specifierLen)); 2252 2253 return keepGoing; 2254} 2255 2256void 2257CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc, 2258 const char *startSpec, 2259 unsigned specifierLen) { 2260 EmitFormatDiagnostic( 2261 S.PDiag(diag::warn_format_mix_positional_nonpositional_args), 2262 Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen)); 2263} 2264 2265bool 2266CheckFormatHandler::CheckNumArgs( 2267 const analyze_format_string::FormatSpecifier &FS, 2268 const analyze_format_string::ConversionSpecifier &CS, 2269 const char *startSpecifier, unsigned specifierLen, unsigned argIndex) { 2270 2271 if (argIndex >= NumDataArgs) { 2272 PartialDiagnostic PDiag = FS.usesPositionalArg() 2273 ? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args) 2274 << (argIndex+1) << NumDataArgs) 2275 : S.PDiag(diag::warn_printf_insufficient_data_args); 2276 EmitFormatDiagnostic( 2277 PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true, 2278 getSpecifierRange(startSpecifier, specifierLen)); 2279 return false; 2280 } 2281 return true; 2282} 2283 2284template<typename Range> 2285void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag, 2286 SourceLocation Loc, 2287 bool IsStringLocation, 2288 Range StringRange, 2289 ArrayRef<FixItHint> FixIt) { 2290 EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag, 2291 Loc, IsStringLocation, StringRange, FixIt); 2292} 2293 2294/// \brief If the format string is not within the funcion call, emit a note 2295/// so that the function call and string are in diagnostic messages. 2296/// 2297/// \param InFunctionCall if true, the format string is within the function 2298/// call and only one diagnostic message will be produced. Otherwise, an 2299/// extra note will be emitted pointing to location of the format string. 2300/// 2301/// \param ArgumentExpr the expression that is passed as the format string 2302/// argument in the function call. Used for getting locations when two 2303/// diagnostics are emitted. 2304/// 2305/// \param PDiag the callee should already have provided any strings for the 2306/// diagnostic message. This function only adds locations and fixits 2307/// to diagnostics. 2308/// 2309/// \param Loc primary location for diagnostic. If two diagnostics are 2310/// required, one will be at Loc and a new SourceLocation will be created for 2311/// the other one. 2312/// 2313/// \param IsStringLocation if true, Loc points to the format string should be 2314/// used for the note. Otherwise, Loc points to the argument list and will 2315/// be used with PDiag. 2316/// 2317/// \param StringRange some or all of the string to highlight. This is 2318/// templated so it can accept either a CharSourceRange or a SourceRange. 2319/// 2320/// \param FixIt optional fix it hint for the format string. 2321template<typename Range> 2322void CheckFormatHandler::EmitFormatDiagnostic(Sema &S, bool InFunctionCall, 2323 const Expr *ArgumentExpr, 2324 PartialDiagnostic PDiag, 2325 SourceLocation Loc, 2326 bool IsStringLocation, 2327 Range StringRange, 2328 ArrayRef<FixItHint> FixIt) { 2329 if (InFunctionCall) { 2330 const Sema::SemaDiagnosticBuilder &D = S.Diag(Loc, PDiag); 2331 D << StringRange; 2332 for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end(); 2333 I != E; ++I) { 2334 D << *I; 2335 } 2336 } else { 2337 S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag) 2338 << ArgumentExpr->getSourceRange(); 2339 2340 const Sema::SemaDiagnosticBuilder &Note = 2341 S.Diag(IsStringLocation ? Loc : StringRange.getBegin(), 2342 diag::note_format_string_defined); 2343 2344 Note << StringRange; 2345 for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end(); 2346 I != E; ++I) { 2347 Note << *I; 2348 } 2349 } 2350} 2351 2352//===--- CHECK: Printf format string checking ------------------------------===// 2353 2354namespace { 2355class CheckPrintfHandler : public CheckFormatHandler { 2356 bool ObjCContext; 2357public: 2358 CheckPrintfHandler(Sema &s, const StringLiteral *fexpr, 2359 const Expr *origFormatExpr, unsigned firstDataArg, 2360 unsigned numDataArgs, bool isObjC, 2361 const char *beg, bool hasVAListArg, 2362 ArrayRef<const Expr *> Args, 2363 unsigned formatIdx, bool inFunctionCall, 2364 Sema::VariadicCallType CallType) 2365 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 2366 numDataArgs, beg, hasVAListArg, Args, 2367 formatIdx, inFunctionCall, CallType), ObjCContext(isObjC) 2368 {} 2369 2370 2371 bool HandleInvalidPrintfConversionSpecifier( 2372 const analyze_printf::PrintfSpecifier &FS, 2373 const char *startSpecifier, 2374 unsigned specifierLen); 2375 2376 bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS, 2377 const char *startSpecifier, 2378 unsigned specifierLen); 2379 bool checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 2380 const char *StartSpecifier, 2381 unsigned SpecifierLen, 2382 const Expr *E); 2383 2384 bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k, 2385 const char *startSpecifier, unsigned specifierLen); 2386 void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS, 2387 const analyze_printf::OptionalAmount &Amt, 2388 unsigned type, 2389 const char *startSpecifier, unsigned specifierLen); 2390 void HandleFlag(const analyze_printf::PrintfSpecifier &FS, 2391 const analyze_printf::OptionalFlag &flag, 2392 const char *startSpecifier, unsigned specifierLen); 2393 void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS, 2394 const analyze_printf::OptionalFlag &ignoredFlag, 2395 const analyze_printf::OptionalFlag &flag, 2396 const char *startSpecifier, unsigned specifierLen); 2397 bool checkForCStrMembers(const analyze_printf::ArgType &AT, 2398 const Expr *E, const CharSourceRange &CSR); 2399 2400}; 2401} 2402 2403bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier( 2404 const analyze_printf::PrintfSpecifier &FS, 2405 const char *startSpecifier, 2406 unsigned specifierLen) { 2407 const analyze_printf::PrintfConversionSpecifier &CS = 2408 FS.getConversionSpecifier(); 2409 2410 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 2411 getLocationOfByte(CS.getStart()), 2412 startSpecifier, specifierLen, 2413 CS.getStart(), CS.getLength()); 2414} 2415 2416bool CheckPrintfHandler::HandleAmount( 2417 const analyze_format_string::OptionalAmount &Amt, 2418 unsigned k, const char *startSpecifier, 2419 unsigned specifierLen) { 2420 2421 if (Amt.hasDataArgument()) { 2422 if (!HasVAListArg) { 2423 unsigned argIndex = Amt.getArgIndex(); 2424 if (argIndex >= NumDataArgs) { 2425 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg) 2426 << k, 2427 getLocationOfByte(Amt.getStart()), 2428 /*IsStringLocation*/true, 2429 getSpecifierRange(startSpecifier, specifierLen)); 2430 // Don't do any more checking. We will just emit 2431 // spurious errors. 2432 return false; 2433 } 2434 2435 // Type check the data argument. It should be an 'int'. 2436 // Although not in conformance with C99, we also allow the argument to be 2437 // an 'unsigned int' as that is a reasonably safe case. GCC also 2438 // doesn't emit a warning for that case. 2439 CoveredArgs.set(argIndex); 2440 const Expr *Arg = getDataArg(argIndex); 2441 if (!Arg) 2442 return false; 2443 2444 QualType T = Arg->getType(); 2445 2446 const analyze_printf::ArgType &AT = Amt.getArgType(S.Context); 2447 assert(AT.isValid()); 2448 2449 if (!AT.matchesType(S.Context, T)) { 2450 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type) 2451 << k << AT.getRepresentativeTypeName(S.Context) 2452 << T << Arg->getSourceRange(), 2453 getLocationOfByte(Amt.getStart()), 2454 /*IsStringLocation*/true, 2455 getSpecifierRange(startSpecifier, specifierLen)); 2456 // Don't do any more checking. We will just emit 2457 // spurious errors. 2458 return false; 2459 } 2460 } 2461 } 2462 return true; 2463} 2464 2465void CheckPrintfHandler::HandleInvalidAmount( 2466 const analyze_printf::PrintfSpecifier &FS, 2467 const analyze_printf::OptionalAmount &Amt, 2468 unsigned type, 2469 const char *startSpecifier, 2470 unsigned specifierLen) { 2471 const analyze_printf::PrintfConversionSpecifier &CS = 2472 FS.getConversionSpecifier(); 2473 2474 FixItHint fixit = 2475 Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant 2476 ? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(), 2477 Amt.getConstantLength())) 2478 : FixItHint(); 2479 2480 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount) 2481 << type << CS.toString(), 2482 getLocationOfByte(Amt.getStart()), 2483 /*IsStringLocation*/true, 2484 getSpecifierRange(startSpecifier, specifierLen), 2485 fixit); 2486} 2487 2488void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS, 2489 const analyze_printf::OptionalFlag &flag, 2490 const char *startSpecifier, 2491 unsigned specifierLen) { 2492 // Warn about pointless flag with a fixit removal. 2493 const analyze_printf::PrintfConversionSpecifier &CS = 2494 FS.getConversionSpecifier(); 2495 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag) 2496 << flag.toString() << CS.toString(), 2497 getLocationOfByte(flag.getPosition()), 2498 /*IsStringLocation*/true, 2499 getSpecifierRange(startSpecifier, specifierLen), 2500 FixItHint::CreateRemoval( 2501 getSpecifierRange(flag.getPosition(), 1))); 2502} 2503 2504void CheckPrintfHandler::HandleIgnoredFlag( 2505 const analyze_printf::PrintfSpecifier &FS, 2506 const analyze_printf::OptionalFlag &ignoredFlag, 2507 const analyze_printf::OptionalFlag &flag, 2508 const char *startSpecifier, 2509 unsigned specifierLen) { 2510 // Warn about ignored flag with a fixit removal. 2511 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag) 2512 << ignoredFlag.toString() << flag.toString(), 2513 getLocationOfByte(ignoredFlag.getPosition()), 2514 /*IsStringLocation*/true, 2515 getSpecifierRange(startSpecifier, specifierLen), 2516 FixItHint::CreateRemoval( 2517 getSpecifierRange(ignoredFlag.getPosition(), 1))); 2518} 2519 2520// Determines if the specified is a C++ class or struct containing 2521// a member with the specified name and kind (e.g. a CXXMethodDecl named 2522// "c_str()"). 2523template<typename MemberKind> 2524static llvm::SmallPtrSet<MemberKind*, 1> 2525CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) { 2526 const RecordType *RT = Ty->getAs<RecordType>(); 2527 llvm::SmallPtrSet<MemberKind*, 1> Results; 2528 2529 if (!RT) 2530 return Results; 2531 const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()); 2532 if (!RD) 2533 return Results; 2534 2535 LookupResult R(S, &S.PP.getIdentifierTable().get(Name), SourceLocation(), 2536 Sema::LookupMemberName); 2537 2538 // We just need to include all members of the right kind turned up by the 2539 // filter, at this point. 2540 if (S.LookupQualifiedName(R, RT->getDecl())) 2541 for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) { 2542 NamedDecl *decl = (*I)->getUnderlyingDecl(); 2543 if (MemberKind *FK = dyn_cast<MemberKind>(decl)) 2544 Results.insert(FK); 2545 } 2546 return Results; 2547} 2548 2549// Check if a (w)string was passed when a (w)char* was needed, and offer a 2550// better diagnostic if so. AT is assumed to be valid. 2551// Returns true when a c_str() conversion method is found. 2552bool CheckPrintfHandler::checkForCStrMembers( 2553 const analyze_printf::ArgType &AT, const Expr *E, 2554 const CharSourceRange &CSR) { 2555 typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet; 2556 2557 MethodSet Results = 2558 CXXRecordMembersNamed<CXXMethodDecl>("c_str", S, E->getType()); 2559 2560 for (MethodSet::iterator MI = Results.begin(), ME = Results.end(); 2561 MI != ME; ++MI) { 2562 const CXXMethodDecl *Method = *MI; 2563 if (Method->getNumParams() == 0 && 2564 AT.matchesType(S.Context, Method->getResultType())) { 2565 // FIXME: Suggest parens if the expression needs them. 2566 SourceLocation EndLoc = 2567 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()); 2568 S.Diag(E->getLocStart(), diag::note_printf_c_str) 2569 << "c_str()" 2570 << FixItHint::CreateInsertion(EndLoc, ".c_str()"); 2571 return true; 2572 } 2573 } 2574 2575 return false; 2576} 2577 2578bool 2579CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier 2580 &FS, 2581 const char *startSpecifier, 2582 unsigned specifierLen) { 2583 2584 using namespace analyze_format_string; 2585 using namespace analyze_printf; 2586 const PrintfConversionSpecifier &CS = FS.getConversionSpecifier(); 2587 2588 if (FS.consumesDataArgument()) { 2589 if (atFirstArg) { 2590 atFirstArg = false; 2591 usesPositionalArgs = FS.usesPositionalArg(); 2592 } 2593 else if (usesPositionalArgs != FS.usesPositionalArg()) { 2594 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 2595 startSpecifier, specifierLen); 2596 return false; 2597 } 2598 } 2599 2600 // First check if the field width, precision, and conversion specifier 2601 // have matching data arguments. 2602 if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0, 2603 startSpecifier, specifierLen)) { 2604 return false; 2605 } 2606 2607 if (!HandleAmount(FS.getPrecision(), /* precision */ 1, 2608 startSpecifier, specifierLen)) { 2609 return false; 2610 } 2611 2612 if (!CS.consumesDataArgument()) { 2613 // FIXME: Technically specifying a precision or field width here 2614 // makes no sense. Worth issuing a warning at some point. 2615 return true; 2616 } 2617 2618 // Consume the argument. 2619 unsigned argIndex = FS.getArgIndex(); 2620 if (argIndex < NumDataArgs) { 2621 // The check to see if the argIndex is valid will come later. 2622 // We set the bit here because we may exit early from this 2623 // function if we encounter some other error. 2624 CoveredArgs.set(argIndex); 2625 } 2626 2627 // Check for using an Objective-C specific conversion specifier 2628 // in a non-ObjC literal. 2629 if (!ObjCContext && CS.isObjCArg()) { 2630 return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier, 2631 specifierLen); 2632 } 2633 2634 // Check for invalid use of field width 2635 if (!FS.hasValidFieldWidth()) { 2636 HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0, 2637 startSpecifier, specifierLen); 2638 } 2639 2640 // Check for invalid use of precision 2641 if (!FS.hasValidPrecision()) { 2642 HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1, 2643 startSpecifier, specifierLen); 2644 } 2645 2646 // Check each flag does not conflict with any other component. 2647 if (!FS.hasValidThousandsGroupingPrefix()) 2648 HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen); 2649 if (!FS.hasValidLeadingZeros()) 2650 HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen); 2651 if (!FS.hasValidPlusPrefix()) 2652 HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen); 2653 if (!FS.hasValidSpacePrefix()) 2654 HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen); 2655 if (!FS.hasValidAlternativeForm()) 2656 HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen); 2657 if (!FS.hasValidLeftJustified()) 2658 HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen); 2659 2660 // Check that flags are not ignored by another flag 2661 if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+' 2662 HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(), 2663 startSpecifier, specifierLen); 2664 if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-' 2665 HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(), 2666 startSpecifier, specifierLen); 2667 2668 // Check the length modifier is valid with the given conversion specifier. 2669 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 2670 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 2671 diag::warn_format_nonsensical_length); 2672 else if (!FS.hasStandardLengthModifier()) 2673 HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen); 2674 else if (!FS.hasStandardLengthConversionCombination()) 2675 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 2676 diag::warn_format_non_standard_conversion_spec); 2677 2678 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 2679 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 2680 2681 // The remaining checks depend on the data arguments. 2682 if (HasVAListArg) 2683 return true; 2684 2685 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 2686 return false; 2687 2688 const Expr *Arg = getDataArg(argIndex); 2689 if (!Arg) 2690 return true; 2691 2692 return checkFormatExpr(FS, startSpecifier, specifierLen, Arg); 2693} 2694 2695static bool requiresParensToAddCast(const Expr *E) { 2696 // FIXME: We should have a general way to reason about operator 2697 // precedence and whether parens are actually needed here. 2698 // Take care of a few common cases where they aren't. 2699 const Expr *Inside = E->IgnoreImpCasts(); 2700 if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Inside)) 2701 Inside = POE->getSyntacticForm()->IgnoreImpCasts(); 2702 2703 switch (Inside->getStmtClass()) { 2704 case Stmt::ArraySubscriptExprClass: 2705 case Stmt::CallExprClass: 2706 case Stmt::CharacterLiteralClass: 2707 case Stmt::CXXBoolLiteralExprClass: 2708 case Stmt::DeclRefExprClass: 2709 case Stmt::FloatingLiteralClass: 2710 case Stmt::IntegerLiteralClass: 2711 case Stmt::MemberExprClass: 2712 case Stmt::ObjCArrayLiteralClass: 2713 case Stmt::ObjCBoolLiteralExprClass: 2714 case Stmt::ObjCBoxedExprClass: 2715 case Stmt::ObjCDictionaryLiteralClass: 2716 case Stmt::ObjCEncodeExprClass: 2717 case Stmt::ObjCIvarRefExprClass: 2718 case Stmt::ObjCMessageExprClass: 2719 case Stmt::ObjCPropertyRefExprClass: 2720 case Stmt::ObjCStringLiteralClass: 2721 case Stmt::ObjCSubscriptRefExprClass: 2722 case Stmt::ParenExprClass: 2723 case Stmt::StringLiteralClass: 2724 case Stmt::UnaryOperatorClass: 2725 return false; 2726 default: 2727 return true; 2728 } 2729} 2730 2731bool 2732CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 2733 const char *StartSpecifier, 2734 unsigned SpecifierLen, 2735 const Expr *E) { 2736 using namespace analyze_format_string; 2737 using namespace analyze_printf; 2738 // Now type check the data expression that matches the 2739 // format specifier. 2740 const analyze_printf::ArgType &AT = FS.getArgType(S.Context, 2741 ObjCContext); 2742 if (!AT.isValid()) 2743 return true; 2744 2745 QualType ExprTy = E->getType(); 2746 while (const TypeOfExprType *TET = dyn_cast<TypeOfExprType>(ExprTy)) { 2747 ExprTy = TET->getUnderlyingExpr()->getType(); 2748 } 2749 2750 if (AT.matchesType(S.Context, ExprTy)) 2751 return true; 2752 2753 // Look through argument promotions for our error message's reported type. 2754 // This includes the integral and floating promotions, but excludes array 2755 // and function pointer decay; seeing that an argument intended to be a 2756 // string has type 'char [6]' is probably more confusing than 'char *'. 2757 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 2758 if (ICE->getCastKind() == CK_IntegralCast || 2759 ICE->getCastKind() == CK_FloatingCast) { 2760 E = ICE->getSubExpr(); 2761 ExprTy = E->getType(); 2762 2763 // Check if we didn't match because of an implicit cast from a 'char' 2764 // or 'short' to an 'int'. This is done because printf is a varargs 2765 // function. 2766 if (ICE->getType() == S.Context.IntTy || 2767 ICE->getType() == S.Context.UnsignedIntTy) { 2768 // All further checking is done on the subexpression. 2769 if (AT.matchesType(S.Context, ExprTy)) 2770 return true; 2771 } 2772 } 2773 } else if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E)) { 2774 // Special case for 'a', which has type 'int' in C. 2775 // Note, however, that we do /not/ want to treat multibyte constants like 2776 // 'MooV' as characters! This form is deprecated but still exists. 2777 if (ExprTy == S.Context.IntTy) 2778 if (llvm::isUIntN(S.Context.getCharWidth(), CL->getValue())) 2779 ExprTy = S.Context.CharTy; 2780 } 2781 2782 // %C in an Objective-C context prints a unichar, not a wchar_t. 2783 // If the argument is an integer of some kind, believe the %C and suggest 2784 // a cast instead of changing the conversion specifier. 2785 QualType IntendedTy = ExprTy; 2786 if (ObjCContext && 2787 FS.getConversionSpecifier().getKind() == ConversionSpecifier::CArg) { 2788 if (ExprTy->isIntegralOrUnscopedEnumerationType() && 2789 !ExprTy->isCharType()) { 2790 // 'unichar' is defined as a typedef of unsigned short, but we should 2791 // prefer using the typedef if it is visible. 2792 IntendedTy = S.Context.UnsignedShortTy; 2793 2794 LookupResult Result(S, &S.Context.Idents.get("unichar"), E->getLocStart(), 2795 Sema::LookupOrdinaryName); 2796 if (S.LookupName(Result, S.getCurScope())) { 2797 NamedDecl *ND = Result.getFoundDecl(); 2798 if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(ND)) 2799 if (TD->getUnderlyingType() == IntendedTy) 2800 IntendedTy = S.Context.getTypedefType(TD); 2801 } 2802 } 2803 } 2804 2805 // Special-case some of Darwin's platform-independence types by suggesting 2806 // casts to primitive types that are known to be large enough. 2807 bool ShouldNotPrintDirectly = false; 2808 if (S.Context.getTargetInfo().getTriple().isOSDarwin()) { 2809 // Use a 'while' to peel off layers of typedefs. 2810 QualType TyTy = IntendedTy; 2811 while (const TypedefType *UserTy = TyTy->getAs<TypedefType>()) { 2812 StringRef Name = UserTy->getDecl()->getName(); 2813 QualType CastTy = llvm::StringSwitch<QualType>(Name) 2814 .Case("NSInteger", S.Context.LongTy) 2815 .Case("NSUInteger", S.Context.UnsignedLongTy) 2816 .Case("SInt32", S.Context.IntTy) 2817 .Case("UInt32", S.Context.UnsignedIntTy) 2818 .Default(QualType()); 2819 2820 if (!CastTy.isNull()) { 2821 ShouldNotPrintDirectly = true; 2822 IntendedTy = CastTy; 2823 break; 2824 } 2825 TyTy = UserTy->desugar(); 2826 } 2827 } 2828 2829 // We may be able to offer a FixItHint if it is a supported type. 2830 PrintfSpecifier fixedFS = FS; 2831 bool success = fixedFS.fixType(IntendedTy, S.getLangOpts(), 2832 S.Context, ObjCContext); 2833 2834 if (success) { 2835 // Get the fix string from the fixed format specifier 2836 SmallString<16> buf; 2837 llvm::raw_svector_ostream os(buf); 2838 fixedFS.toString(os); 2839 2840 CharSourceRange SpecRange = getSpecifierRange(StartSpecifier, SpecifierLen); 2841 2842 if (IntendedTy == ExprTy) { 2843 // In this case, the specifier is wrong and should be changed to match 2844 // the argument. 2845 EmitFormatDiagnostic( 2846 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2847 << AT.getRepresentativeTypeName(S.Context) << IntendedTy 2848 << E->getSourceRange(), 2849 E->getLocStart(), 2850 /*IsStringLocation*/false, 2851 SpecRange, 2852 FixItHint::CreateReplacement(SpecRange, os.str())); 2853 2854 } else { 2855 // The canonical type for formatting this value is different from the 2856 // actual type of the expression. (This occurs, for example, with Darwin's 2857 // NSInteger on 32-bit platforms, where it is typedef'd as 'int', but 2858 // should be printed as 'long' for 64-bit compatibility.) 2859 // Rather than emitting a normal format/argument mismatch, we want to 2860 // add a cast to the recommended type (and correct the format string 2861 // if necessary). 2862 SmallString<16> CastBuf; 2863 llvm::raw_svector_ostream CastFix(CastBuf); 2864 CastFix << "("; 2865 IntendedTy.print(CastFix, S.Context.getPrintingPolicy()); 2866 CastFix << ")"; 2867 2868 SmallVector<FixItHint,4> Hints; 2869 if (!AT.matchesType(S.Context, IntendedTy)) 2870 Hints.push_back(FixItHint::CreateReplacement(SpecRange, os.str())); 2871 2872 if (const CStyleCastExpr *CCast = dyn_cast<CStyleCastExpr>(E)) { 2873 // If there's already a cast present, just replace it. 2874 SourceRange CastRange(CCast->getLParenLoc(), CCast->getRParenLoc()); 2875 Hints.push_back(FixItHint::CreateReplacement(CastRange, CastFix.str())); 2876 2877 } else if (!requiresParensToAddCast(E)) { 2878 // If the expression has high enough precedence, 2879 // just write the C-style cast. 2880 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 2881 CastFix.str())); 2882 } else { 2883 // Otherwise, add parens around the expression as well as the cast. 2884 CastFix << "("; 2885 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 2886 CastFix.str())); 2887 2888 SourceLocation After = S.PP.getLocForEndOfToken(E->getLocEnd()); 2889 Hints.push_back(FixItHint::CreateInsertion(After, ")")); 2890 } 2891 2892 if (ShouldNotPrintDirectly) { 2893 // The expression has a type that should not be printed directly. 2894 // We extract the name from the typedef because we don't want to show 2895 // the underlying type in the diagnostic. 2896 StringRef Name = cast<TypedefType>(ExprTy)->getDecl()->getName(); 2897 2898 EmitFormatDiagnostic(S.PDiag(diag::warn_format_argument_needs_cast) 2899 << Name << IntendedTy 2900 << E->getSourceRange(), 2901 E->getLocStart(), /*IsStringLocation=*/false, 2902 SpecRange, Hints); 2903 } else { 2904 // In this case, the expression could be printed using a different 2905 // specifier, but we've decided that the specifier is probably correct 2906 // and we should cast instead. Just use the normal warning message. 2907 EmitFormatDiagnostic( 2908 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2909 << AT.getRepresentativeTypeName(S.Context) << ExprTy 2910 << E->getSourceRange(), 2911 E->getLocStart(), /*IsStringLocation*/false, 2912 SpecRange, Hints); 2913 } 2914 } 2915 } else { 2916 const CharSourceRange &CSR = getSpecifierRange(StartSpecifier, 2917 SpecifierLen); 2918 // Since the warning for passing non-POD types to variadic functions 2919 // was deferred until now, we emit a warning for non-POD 2920 // arguments here. 2921 if (S.isValidVarArgType(ExprTy) == Sema::VAK_Invalid) { 2922 unsigned DiagKind; 2923 if (ExprTy->isObjCObjectType()) 2924 DiagKind = diag::err_cannot_pass_objc_interface_to_vararg_format; 2925 else 2926 DiagKind = diag::warn_non_pod_vararg_with_format_string; 2927 2928 EmitFormatDiagnostic( 2929 S.PDiag(DiagKind) 2930 << S.getLangOpts().CPlusPlus11 2931 << ExprTy 2932 << CallType 2933 << AT.getRepresentativeTypeName(S.Context) 2934 << CSR 2935 << E->getSourceRange(), 2936 E->getLocStart(), /*IsStringLocation*/false, CSR); 2937 2938 checkForCStrMembers(AT, E, CSR); 2939 } else 2940 EmitFormatDiagnostic( 2941 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2942 << AT.getRepresentativeTypeName(S.Context) << ExprTy 2943 << CSR 2944 << E->getSourceRange(), 2945 E->getLocStart(), /*IsStringLocation*/false, CSR); 2946 } 2947 2948 return true; 2949} 2950 2951//===--- CHECK: Scanf format string checking ------------------------------===// 2952 2953namespace { 2954class CheckScanfHandler : public CheckFormatHandler { 2955public: 2956 CheckScanfHandler(Sema &s, const StringLiteral *fexpr, 2957 const Expr *origFormatExpr, unsigned firstDataArg, 2958 unsigned numDataArgs, const char *beg, bool hasVAListArg, 2959 ArrayRef<const Expr *> Args, 2960 unsigned formatIdx, bool inFunctionCall, 2961 Sema::VariadicCallType CallType) 2962 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 2963 numDataArgs, beg, hasVAListArg, 2964 Args, formatIdx, inFunctionCall, CallType) 2965 {} 2966 2967 bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS, 2968 const char *startSpecifier, 2969 unsigned specifierLen); 2970 2971 bool HandleInvalidScanfConversionSpecifier( 2972 const analyze_scanf::ScanfSpecifier &FS, 2973 const char *startSpecifier, 2974 unsigned specifierLen); 2975 2976 void HandleIncompleteScanList(const char *start, const char *end); 2977}; 2978} 2979 2980void CheckScanfHandler::HandleIncompleteScanList(const char *start, 2981 const char *end) { 2982 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete), 2983 getLocationOfByte(end), /*IsStringLocation*/true, 2984 getSpecifierRange(start, end - start)); 2985} 2986 2987bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier( 2988 const analyze_scanf::ScanfSpecifier &FS, 2989 const char *startSpecifier, 2990 unsigned specifierLen) { 2991 2992 const analyze_scanf::ScanfConversionSpecifier &CS = 2993 FS.getConversionSpecifier(); 2994 2995 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 2996 getLocationOfByte(CS.getStart()), 2997 startSpecifier, specifierLen, 2998 CS.getStart(), CS.getLength()); 2999} 3000 3001bool CheckScanfHandler::HandleScanfSpecifier( 3002 const analyze_scanf::ScanfSpecifier &FS, 3003 const char *startSpecifier, 3004 unsigned specifierLen) { 3005 3006 using namespace analyze_scanf; 3007 using namespace analyze_format_string; 3008 3009 const ScanfConversionSpecifier &CS = FS.getConversionSpecifier(); 3010 3011 // Handle case where '%' and '*' don't consume an argument. These shouldn't 3012 // be used to decide if we are using positional arguments consistently. 3013 if (FS.consumesDataArgument()) { 3014 if (atFirstArg) { 3015 atFirstArg = false; 3016 usesPositionalArgs = FS.usesPositionalArg(); 3017 } 3018 else if (usesPositionalArgs != FS.usesPositionalArg()) { 3019 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 3020 startSpecifier, specifierLen); 3021 return false; 3022 } 3023 } 3024 3025 // Check if the field with is non-zero. 3026 const OptionalAmount &Amt = FS.getFieldWidth(); 3027 if (Amt.getHowSpecified() == OptionalAmount::Constant) { 3028 if (Amt.getConstantAmount() == 0) { 3029 const CharSourceRange &R = getSpecifierRange(Amt.getStart(), 3030 Amt.getConstantLength()); 3031 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width), 3032 getLocationOfByte(Amt.getStart()), 3033 /*IsStringLocation*/true, R, 3034 FixItHint::CreateRemoval(R)); 3035 } 3036 } 3037 3038 if (!FS.consumesDataArgument()) { 3039 // FIXME: Technically specifying a precision or field width here 3040 // makes no sense. Worth issuing a warning at some point. 3041 return true; 3042 } 3043 3044 // Consume the argument. 3045 unsigned argIndex = FS.getArgIndex(); 3046 if (argIndex < NumDataArgs) { 3047 // The check to see if the argIndex is valid will come later. 3048 // We set the bit here because we may exit early from this 3049 // function if we encounter some other error. 3050 CoveredArgs.set(argIndex); 3051 } 3052 3053 // Check the length modifier is valid with the given conversion specifier. 3054 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 3055 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 3056 diag::warn_format_nonsensical_length); 3057 else if (!FS.hasStandardLengthModifier()) 3058 HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen); 3059 else if (!FS.hasStandardLengthConversionCombination()) 3060 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 3061 diag::warn_format_non_standard_conversion_spec); 3062 3063 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 3064 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 3065 3066 // The remaining checks depend on the data arguments. 3067 if (HasVAListArg) 3068 return true; 3069 3070 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 3071 return false; 3072 3073 // Check that the argument type matches the format specifier. 3074 const Expr *Ex = getDataArg(argIndex); 3075 if (!Ex) 3076 return true; 3077 3078 const analyze_format_string::ArgType &AT = FS.getArgType(S.Context); 3079 if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType())) { 3080 ScanfSpecifier fixedFS = FS; 3081 bool success = fixedFS.fixType(Ex->getType(), S.getLangOpts(), 3082 S.Context); 3083 3084 if (success) { 3085 // Get the fix string from the fixed format specifier. 3086 SmallString<128> buf; 3087 llvm::raw_svector_ostream os(buf); 3088 fixedFS.toString(os); 3089 3090 EmitFormatDiagnostic( 3091 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 3092 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() 3093 << Ex->getSourceRange(), 3094 Ex->getLocStart(), 3095 /*IsStringLocation*/false, 3096 getSpecifierRange(startSpecifier, specifierLen), 3097 FixItHint::CreateReplacement( 3098 getSpecifierRange(startSpecifier, specifierLen), 3099 os.str())); 3100 } else { 3101 EmitFormatDiagnostic( 3102 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 3103 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() 3104 << Ex->getSourceRange(), 3105 Ex->getLocStart(), 3106 /*IsStringLocation*/false, 3107 getSpecifierRange(startSpecifier, specifierLen)); 3108 } 3109 } 3110 3111 return true; 3112} 3113 3114void Sema::CheckFormatString(const StringLiteral *FExpr, 3115 const Expr *OrigFormatExpr, 3116 ArrayRef<const Expr *> Args, 3117 bool HasVAListArg, unsigned format_idx, 3118 unsigned firstDataArg, FormatStringType Type, 3119 bool inFunctionCall, VariadicCallType CallType) { 3120 3121 // CHECK: is the format string a wide literal? 3122 if (!FExpr->isAscii() && !FExpr->isUTF8()) { 3123 CheckFormatHandler::EmitFormatDiagnostic( 3124 *this, inFunctionCall, Args[format_idx], 3125 PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(), 3126 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 3127 return; 3128 } 3129 3130 // Str - The format string. NOTE: this is NOT null-terminated! 3131 StringRef StrRef = FExpr->getString(); 3132 const char *Str = StrRef.data(); 3133 unsigned StrLen = StrRef.size(); 3134 const unsigned numDataArgs = Args.size() - firstDataArg; 3135 3136 // CHECK: empty format string? 3137 if (StrLen == 0 && numDataArgs > 0) { 3138 CheckFormatHandler::EmitFormatDiagnostic( 3139 *this, inFunctionCall, Args[format_idx], 3140 PDiag(diag::warn_empty_format_string), FExpr->getLocStart(), 3141 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 3142 return; 3143 } 3144 3145 if (Type == FST_Printf || Type == FST_NSString) { 3146 CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 3147 numDataArgs, (Type == FST_NSString), 3148 Str, HasVAListArg, Args, format_idx, 3149 inFunctionCall, CallType); 3150 3151 if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen, 3152 getLangOpts(), 3153 Context.getTargetInfo())) 3154 H.DoneProcessing(); 3155 } else if (Type == FST_Scanf) { 3156 CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, numDataArgs, 3157 Str, HasVAListArg, Args, format_idx, 3158 inFunctionCall, CallType); 3159 3160 if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen, 3161 getLangOpts(), 3162 Context.getTargetInfo())) 3163 H.DoneProcessing(); 3164 } // TODO: handle other formats 3165} 3166 3167//===--- CHECK: Standard memory functions ---------------------------------===// 3168 3169/// \brief Determine whether the given type is a dynamic class type (e.g., 3170/// whether it has a vtable). 3171static bool isDynamicClassType(QualType T) { 3172 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) 3173 if (CXXRecordDecl *Definition = Record->getDefinition()) 3174 if (Definition->isDynamicClass()) 3175 return true; 3176 3177 return false; 3178} 3179 3180/// \brief If E is a sizeof expression, returns its argument expression, 3181/// otherwise returns NULL. 3182static const Expr *getSizeOfExprArg(const Expr* E) { 3183 if (const UnaryExprOrTypeTraitExpr *SizeOf = 3184 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 3185 if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType()) 3186 return SizeOf->getArgumentExpr()->IgnoreParenImpCasts(); 3187 3188 return 0; 3189} 3190 3191/// \brief If E is a sizeof expression, returns its argument type. 3192static QualType getSizeOfArgType(const Expr* E) { 3193 if (const UnaryExprOrTypeTraitExpr *SizeOf = 3194 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 3195 if (SizeOf->getKind() == clang::UETT_SizeOf) 3196 return SizeOf->getTypeOfArgument(); 3197 3198 return QualType(); 3199} 3200 3201/// \brief Check for dangerous or invalid arguments to memset(). 3202/// 3203/// This issues warnings on known problematic, dangerous or unspecified 3204/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp' 3205/// function calls. 3206/// 3207/// \param Call The call expression to diagnose. 3208void Sema::CheckMemaccessArguments(const CallExpr *Call, 3209 unsigned BId, 3210 IdentifierInfo *FnName) { 3211 assert(BId != 0); 3212 3213 // It is possible to have a non-standard definition of memset. Validate 3214 // we have enough arguments, and if not, abort further checking. 3215 unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3); 3216 if (Call->getNumArgs() < ExpectedNumArgs) 3217 return; 3218 3219 unsigned LastArg = (BId == Builtin::BImemset || 3220 BId == Builtin::BIstrndup ? 1 : 2); 3221 unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2); 3222 const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts(); 3223 3224 // We have special checking when the length is a sizeof expression. 3225 QualType SizeOfArgTy = getSizeOfArgType(LenExpr); 3226 const Expr *SizeOfArg = getSizeOfExprArg(LenExpr); 3227 llvm::FoldingSetNodeID SizeOfArgID; 3228 3229 for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) { 3230 const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts(); 3231 SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange(); 3232 3233 QualType DestTy = Dest->getType(); 3234 if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) { 3235 QualType PointeeTy = DestPtrTy->getPointeeType(); 3236 3237 // Never warn about void type pointers. This can be used to suppress 3238 // false positives. 3239 if (PointeeTy->isVoidType()) 3240 continue; 3241 3242 // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by 3243 // actually comparing the expressions for equality. Because computing the 3244 // expression IDs can be expensive, we only do this if the diagnostic is 3245 // enabled. 3246 if (SizeOfArg && 3247 Diags.getDiagnosticLevel(diag::warn_sizeof_pointer_expr_memaccess, 3248 SizeOfArg->getExprLoc())) { 3249 // We only compute IDs for expressions if the warning is enabled, and 3250 // cache the sizeof arg's ID. 3251 if (SizeOfArgID == llvm::FoldingSetNodeID()) 3252 SizeOfArg->Profile(SizeOfArgID, Context, true); 3253 llvm::FoldingSetNodeID DestID; 3254 Dest->Profile(DestID, Context, true); 3255 if (DestID == SizeOfArgID) { 3256 // TODO: For strncpy() and friends, this could suggest sizeof(dst) 3257 // over sizeof(src) as well. 3258 unsigned ActionIdx = 0; // Default is to suggest dereferencing. 3259 StringRef ReadableName = FnName->getName(); 3260 3261 if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest)) 3262 if (UnaryOp->getOpcode() == UO_AddrOf) 3263 ActionIdx = 1; // If its an address-of operator, just remove it. 3264 if (!PointeeTy->isIncompleteType() && 3265 (Context.getTypeSize(PointeeTy) == Context.getCharWidth())) 3266 ActionIdx = 2; // If the pointee's size is sizeof(char), 3267 // suggest an explicit length. 3268 3269 // If the function is defined as a builtin macro, do not show macro 3270 // expansion. 3271 SourceLocation SL = SizeOfArg->getExprLoc(); 3272 SourceRange DSR = Dest->getSourceRange(); 3273 SourceRange SSR = SizeOfArg->getSourceRange(); 3274 SourceManager &SM = PP.getSourceManager(); 3275 3276 if (SM.isMacroArgExpansion(SL)) { 3277 ReadableName = Lexer::getImmediateMacroName(SL, SM, LangOpts); 3278 SL = SM.getSpellingLoc(SL); 3279 DSR = SourceRange(SM.getSpellingLoc(DSR.getBegin()), 3280 SM.getSpellingLoc(DSR.getEnd())); 3281 SSR = SourceRange(SM.getSpellingLoc(SSR.getBegin()), 3282 SM.getSpellingLoc(SSR.getEnd())); 3283 } 3284 3285 DiagRuntimeBehavior(SL, SizeOfArg, 3286 PDiag(diag::warn_sizeof_pointer_expr_memaccess) 3287 << ReadableName 3288 << PointeeTy 3289 << DestTy 3290 << DSR 3291 << SSR); 3292 DiagRuntimeBehavior(SL, SizeOfArg, 3293 PDiag(diag::warn_sizeof_pointer_expr_memaccess_note) 3294 << ActionIdx 3295 << SSR); 3296 3297 break; 3298 } 3299 } 3300 3301 // Also check for cases where the sizeof argument is the exact same 3302 // type as the memory argument, and where it points to a user-defined 3303 // record type. 3304 if (SizeOfArgTy != QualType()) { 3305 if (PointeeTy->isRecordType() && 3306 Context.typesAreCompatible(SizeOfArgTy, DestTy)) { 3307 DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest, 3308 PDiag(diag::warn_sizeof_pointer_type_memaccess) 3309 << FnName << SizeOfArgTy << ArgIdx 3310 << PointeeTy << Dest->getSourceRange() 3311 << LenExpr->getSourceRange()); 3312 break; 3313 } 3314 } 3315 3316 // Always complain about dynamic classes. 3317 if (isDynamicClassType(PointeeTy)) { 3318 3319 unsigned OperationType = 0; 3320 // "overwritten" if we're warning about the destination for any call 3321 // but memcmp; otherwise a verb appropriate to the call. 3322 if (ArgIdx != 0 || BId == Builtin::BImemcmp) { 3323 if (BId == Builtin::BImemcpy) 3324 OperationType = 1; 3325 else if(BId == Builtin::BImemmove) 3326 OperationType = 2; 3327 else if (BId == Builtin::BImemcmp) 3328 OperationType = 3; 3329 } 3330 3331 DiagRuntimeBehavior( 3332 Dest->getExprLoc(), Dest, 3333 PDiag(diag::warn_dyn_class_memaccess) 3334 << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx) 3335 << FnName << PointeeTy 3336 << OperationType 3337 << Call->getCallee()->getSourceRange()); 3338 } else if (PointeeTy.hasNonTrivialObjCLifetime() && 3339 BId != Builtin::BImemset) 3340 DiagRuntimeBehavior( 3341 Dest->getExprLoc(), Dest, 3342 PDiag(diag::warn_arc_object_memaccess) 3343 << ArgIdx << FnName << PointeeTy 3344 << Call->getCallee()->getSourceRange()); 3345 else 3346 continue; 3347 3348 DiagRuntimeBehavior( 3349 Dest->getExprLoc(), Dest, 3350 PDiag(diag::note_bad_memaccess_silence) 3351 << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)")); 3352 break; 3353 } 3354 } 3355} 3356 3357// A little helper routine: ignore addition and subtraction of integer literals. 3358// This intentionally does not ignore all integer constant expressions because 3359// we don't want to remove sizeof(). 3360static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) { 3361 Ex = Ex->IgnoreParenCasts(); 3362 3363 for (;;) { 3364 const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex); 3365 if (!BO || !BO->isAdditiveOp()) 3366 break; 3367 3368 const Expr *RHS = BO->getRHS()->IgnoreParenCasts(); 3369 const Expr *LHS = BO->getLHS()->IgnoreParenCasts(); 3370 3371 if (isa<IntegerLiteral>(RHS)) 3372 Ex = LHS; 3373 else if (isa<IntegerLiteral>(LHS)) 3374 Ex = RHS; 3375 else 3376 break; 3377 } 3378 3379 return Ex; 3380} 3381 3382static bool isConstantSizeArrayWithMoreThanOneElement(QualType Ty, 3383 ASTContext &Context) { 3384 // Only handle constant-sized or VLAs, but not flexible members. 3385 if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(Ty)) { 3386 // Only issue the FIXIT for arrays of size > 1. 3387 if (CAT->getSize().getSExtValue() <= 1) 3388 return false; 3389 } else if (!Ty->isVariableArrayType()) { 3390 return false; 3391 } 3392 return true; 3393} 3394 3395// Warn if the user has made the 'size' argument to strlcpy or strlcat 3396// be the size of the source, instead of the destination. 3397void Sema::CheckStrlcpycatArguments(const CallExpr *Call, 3398 IdentifierInfo *FnName) { 3399 3400 // Don't crash if the user has the wrong number of arguments 3401 if (Call->getNumArgs() != 3) 3402 return; 3403 3404 const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context); 3405 const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context); 3406 const Expr *CompareWithSrc = NULL; 3407 3408 // Look for 'strlcpy(dst, x, sizeof(x))' 3409 if (const Expr *Ex = getSizeOfExprArg(SizeArg)) 3410 CompareWithSrc = Ex; 3411 else { 3412 // Look for 'strlcpy(dst, x, strlen(x))' 3413 if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) { 3414 if (SizeCall->isBuiltinCall() == Builtin::BIstrlen 3415 && SizeCall->getNumArgs() == 1) 3416 CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context); 3417 } 3418 } 3419 3420 if (!CompareWithSrc) 3421 return; 3422 3423 // Determine if the argument to sizeof/strlen is equal to the source 3424 // argument. In principle there's all kinds of things you could do 3425 // here, for instance creating an == expression and evaluating it with 3426 // EvaluateAsBooleanCondition, but this uses a more direct technique: 3427 const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg); 3428 if (!SrcArgDRE) 3429 return; 3430 3431 const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc); 3432 if (!CompareWithSrcDRE || 3433 SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl()) 3434 return; 3435 3436 const Expr *OriginalSizeArg = Call->getArg(2); 3437 Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size) 3438 << OriginalSizeArg->getSourceRange() << FnName; 3439 3440 // Output a FIXIT hint if the destination is an array (rather than a 3441 // pointer to an array). This could be enhanced to handle some 3442 // pointers if we know the actual size, like if DstArg is 'array+2' 3443 // we could say 'sizeof(array)-2'. 3444 const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts(); 3445 if (!isConstantSizeArrayWithMoreThanOneElement(DstArg->getType(), Context)) 3446 return; 3447 3448 SmallString<128> sizeString; 3449 llvm::raw_svector_ostream OS(sizeString); 3450 OS << "sizeof("; 3451 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3452 OS << ")"; 3453 3454 Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size) 3455 << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(), 3456 OS.str()); 3457} 3458 3459/// Check if two expressions refer to the same declaration. 3460static bool referToTheSameDecl(const Expr *E1, const Expr *E2) { 3461 if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1)) 3462 if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2)) 3463 return D1->getDecl() == D2->getDecl(); 3464 return false; 3465} 3466 3467static const Expr *getStrlenExprArg(const Expr *E) { 3468 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 3469 const FunctionDecl *FD = CE->getDirectCallee(); 3470 if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen) 3471 return 0; 3472 return CE->getArg(0)->IgnoreParenCasts(); 3473 } 3474 return 0; 3475} 3476 3477// Warn on anti-patterns as the 'size' argument to strncat. 3478// The correct size argument should look like following: 3479// strncat(dst, src, sizeof(dst) - strlen(dest) - 1); 3480void Sema::CheckStrncatArguments(const CallExpr *CE, 3481 IdentifierInfo *FnName) { 3482 // Don't crash if the user has the wrong number of arguments. 3483 if (CE->getNumArgs() < 3) 3484 return; 3485 const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts(); 3486 const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts(); 3487 const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts(); 3488 3489 // Identify common expressions, which are wrongly used as the size argument 3490 // to strncat and may lead to buffer overflows. 3491 unsigned PatternType = 0; 3492 if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) { 3493 // - sizeof(dst) 3494 if (referToTheSameDecl(SizeOfArg, DstArg)) 3495 PatternType = 1; 3496 // - sizeof(src) 3497 else if (referToTheSameDecl(SizeOfArg, SrcArg)) 3498 PatternType = 2; 3499 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) { 3500 if (BE->getOpcode() == BO_Sub) { 3501 const Expr *L = BE->getLHS()->IgnoreParenCasts(); 3502 const Expr *R = BE->getRHS()->IgnoreParenCasts(); 3503 // - sizeof(dst) - strlen(dst) 3504 if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) && 3505 referToTheSameDecl(DstArg, getStrlenExprArg(R))) 3506 PatternType = 1; 3507 // - sizeof(src) - (anything) 3508 else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L))) 3509 PatternType = 2; 3510 } 3511 } 3512 3513 if (PatternType == 0) 3514 return; 3515 3516 // Generate the diagnostic. 3517 SourceLocation SL = LenArg->getLocStart(); 3518 SourceRange SR = LenArg->getSourceRange(); 3519 SourceManager &SM = PP.getSourceManager(); 3520 3521 // If the function is defined as a builtin macro, do not show macro expansion. 3522 if (SM.isMacroArgExpansion(SL)) { 3523 SL = SM.getSpellingLoc(SL); 3524 SR = SourceRange(SM.getSpellingLoc(SR.getBegin()), 3525 SM.getSpellingLoc(SR.getEnd())); 3526 } 3527 3528 // Check if the destination is an array (rather than a pointer to an array). 3529 QualType DstTy = DstArg->getType(); 3530 bool isKnownSizeArray = isConstantSizeArrayWithMoreThanOneElement(DstTy, 3531 Context); 3532 if (!isKnownSizeArray) { 3533 if (PatternType == 1) 3534 Diag(SL, diag::warn_strncat_wrong_size) << SR; 3535 else 3536 Diag(SL, diag::warn_strncat_src_size) << SR; 3537 return; 3538 } 3539 3540 if (PatternType == 1) 3541 Diag(SL, diag::warn_strncat_large_size) << SR; 3542 else 3543 Diag(SL, diag::warn_strncat_src_size) << SR; 3544 3545 SmallString<128> sizeString; 3546 llvm::raw_svector_ostream OS(sizeString); 3547 OS << "sizeof("; 3548 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3549 OS << ") - "; 3550 OS << "strlen("; 3551 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3552 OS << ") - 1"; 3553 3554 Diag(SL, diag::note_strncat_wrong_size) 3555 << FixItHint::CreateReplacement(SR, OS.str()); 3556} 3557 3558//===--- CHECK: Return Address of Stack Variable --------------------------===// 3559 3560static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3561 Decl *ParentDecl); 3562static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars, 3563 Decl *ParentDecl); 3564 3565/// CheckReturnStackAddr - Check if a return statement returns the address 3566/// of a stack variable. 3567void 3568Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType, 3569 SourceLocation ReturnLoc) { 3570 3571 Expr *stackE = 0; 3572 SmallVector<DeclRefExpr *, 8> refVars; 3573 3574 // Perform checking for returned stack addresses, local blocks, 3575 // label addresses or references to temporaries. 3576 if (lhsType->isPointerType() || 3577 (!getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) { 3578 stackE = EvalAddr(RetValExp, refVars, /*ParentDecl=*/0); 3579 } else if (lhsType->isReferenceType()) { 3580 stackE = EvalVal(RetValExp, refVars, /*ParentDecl=*/0); 3581 } 3582 3583 if (stackE == 0) 3584 return; // Nothing suspicious was found. 3585 3586 SourceLocation diagLoc; 3587 SourceRange diagRange; 3588 if (refVars.empty()) { 3589 diagLoc = stackE->getLocStart(); 3590 diagRange = stackE->getSourceRange(); 3591 } else { 3592 // We followed through a reference variable. 'stackE' contains the 3593 // problematic expression but we will warn at the return statement pointing 3594 // at the reference variable. We will later display the "trail" of 3595 // reference variables using notes. 3596 diagLoc = refVars[0]->getLocStart(); 3597 diagRange = refVars[0]->getSourceRange(); 3598 } 3599 3600 if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var. 3601 Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref 3602 : diag::warn_ret_stack_addr) 3603 << DR->getDecl()->getDeclName() << diagRange; 3604 } else if (isa<BlockExpr>(stackE)) { // local block. 3605 Diag(diagLoc, diag::err_ret_local_block) << diagRange; 3606 } else if (isa<AddrLabelExpr>(stackE)) { // address of label. 3607 Diag(diagLoc, diag::warn_ret_addr_label) << diagRange; 3608 } else { // local temporary. 3609 Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref 3610 : diag::warn_ret_local_temp_addr) 3611 << diagRange; 3612 } 3613 3614 // Display the "trail" of reference variables that we followed until we 3615 // found the problematic expression using notes. 3616 for (unsigned i = 0, e = refVars.size(); i != e; ++i) { 3617 VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl()); 3618 // If this var binds to another reference var, show the range of the next 3619 // var, otherwise the var binds to the problematic expression, in which case 3620 // show the range of the expression. 3621 SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange() 3622 : stackE->getSourceRange(); 3623 Diag(VD->getLocation(), diag::note_ref_var_local_bind) 3624 << VD->getDeclName() << range; 3625 } 3626} 3627 3628/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that 3629/// check if the expression in a return statement evaluates to an address 3630/// to a location on the stack, a local block, an address of a label, or a 3631/// reference to local temporary. The recursion is used to traverse the 3632/// AST of the return expression, with recursion backtracking when we 3633/// encounter a subexpression that (1) clearly does not lead to one of the 3634/// above problematic expressions (2) is something we cannot determine leads to 3635/// a problematic expression based on such local checking. 3636/// 3637/// Both EvalAddr and EvalVal follow through reference variables to evaluate 3638/// the expression that they point to. Such variables are added to the 3639/// 'refVars' vector so that we know what the reference variable "trail" was. 3640/// 3641/// EvalAddr processes expressions that are pointers that are used as 3642/// references (and not L-values). EvalVal handles all other values. 3643/// At the base case of the recursion is a check for the above problematic 3644/// expressions. 3645/// 3646/// This implementation handles: 3647/// 3648/// * pointer-to-pointer casts 3649/// * implicit conversions from array references to pointers 3650/// * taking the address of fields 3651/// * arbitrary interplay between "&" and "*" operators 3652/// * pointer arithmetic from an address of a stack variable 3653/// * taking the address of an array element where the array is on the stack 3654static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3655 Decl *ParentDecl) { 3656 if (E->isTypeDependent()) 3657 return NULL; 3658 3659 // We should only be called for evaluating pointer expressions. 3660 assert((E->getType()->isAnyPointerType() || 3661 E->getType()->isBlockPointerType() || 3662 E->getType()->isObjCQualifiedIdType()) && 3663 "EvalAddr only works on pointers"); 3664 3665 E = E->IgnoreParens(); 3666 3667 // Our "symbolic interpreter" is just a dispatch off the currently 3668 // viewed AST node. We then recursively traverse the AST by calling 3669 // EvalAddr and EvalVal appropriately. 3670 switch (E->getStmtClass()) { 3671 case Stmt::DeclRefExprClass: { 3672 DeclRefExpr *DR = cast<DeclRefExpr>(E); 3673 3674 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) 3675 // If this is a reference variable, follow through to the expression that 3676 // it points to. 3677 if (V->hasLocalStorage() && 3678 V->getType()->isReferenceType() && V->hasInit()) { 3679 // Add the reference variable to the "trail". 3680 refVars.push_back(DR); 3681 return EvalAddr(V->getInit(), refVars, ParentDecl); 3682 } 3683 3684 return NULL; 3685 } 3686 3687 case Stmt::UnaryOperatorClass: { 3688 // The only unary operator that make sense to handle here 3689 // is AddrOf. All others don't make sense as pointers. 3690 UnaryOperator *U = cast<UnaryOperator>(E); 3691 3692 if (U->getOpcode() == UO_AddrOf) 3693 return EvalVal(U->getSubExpr(), refVars, ParentDecl); 3694 else 3695 return NULL; 3696 } 3697 3698 case Stmt::BinaryOperatorClass: { 3699 // Handle pointer arithmetic. All other binary operators are not valid 3700 // in this context. 3701 BinaryOperator *B = cast<BinaryOperator>(E); 3702 BinaryOperatorKind op = B->getOpcode(); 3703 3704 if (op != BO_Add && op != BO_Sub) 3705 return NULL; 3706 3707 Expr *Base = B->getLHS(); 3708 3709 // Determine which argument is the real pointer base. It could be 3710 // the RHS argument instead of the LHS. 3711 if (!Base->getType()->isPointerType()) Base = B->getRHS(); 3712 3713 assert (Base->getType()->isPointerType()); 3714 return EvalAddr(Base, refVars, ParentDecl); 3715 } 3716 3717 // For conditional operators we need to see if either the LHS or RHS are 3718 // valid DeclRefExpr*s. If one of them is valid, we return it. 3719 case Stmt::ConditionalOperatorClass: { 3720 ConditionalOperator *C = cast<ConditionalOperator>(E); 3721 3722 // Handle the GNU extension for missing LHS. 3723 if (Expr *lhsExpr = C->getLHS()) { 3724 // In C++, we can have a throw-expression, which has 'void' type. 3725 if (!lhsExpr->getType()->isVoidType()) 3726 if (Expr* LHS = EvalAddr(lhsExpr, refVars, ParentDecl)) 3727 return LHS; 3728 } 3729 3730 // In C++, we can have a throw-expression, which has 'void' type. 3731 if (C->getRHS()->getType()->isVoidType()) 3732 return NULL; 3733 3734 return EvalAddr(C->getRHS(), refVars, ParentDecl); 3735 } 3736 3737 case Stmt::BlockExprClass: 3738 if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures()) 3739 return E; // local block. 3740 return NULL; 3741 3742 case Stmt::AddrLabelExprClass: 3743 return E; // address of label. 3744 3745 case Stmt::ExprWithCleanupsClass: 3746 return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars, 3747 ParentDecl); 3748 3749 // For casts, we need to handle conversions from arrays to 3750 // pointer values, and pointer-to-pointer conversions. 3751 case Stmt::ImplicitCastExprClass: 3752 case Stmt::CStyleCastExprClass: 3753 case Stmt::CXXFunctionalCastExprClass: 3754 case Stmt::ObjCBridgedCastExprClass: 3755 case Stmt::CXXStaticCastExprClass: 3756 case Stmt::CXXDynamicCastExprClass: 3757 case Stmt::CXXConstCastExprClass: 3758 case Stmt::CXXReinterpretCastExprClass: { 3759 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr(); 3760 switch (cast<CastExpr>(E)->getCastKind()) { 3761 case CK_BitCast: 3762 case CK_LValueToRValue: 3763 case CK_NoOp: 3764 case CK_BaseToDerived: 3765 case CK_DerivedToBase: 3766 case CK_UncheckedDerivedToBase: 3767 case CK_Dynamic: 3768 case CK_CPointerToObjCPointerCast: 3769 case CK_BlockPointerToObjCPointerCast: 3770 case CK_AnyPointerToBlockPointerCast: 3771 return EvalAddr(SubExpr, refVars, ParentDecl); 3772 3773 case CK_ArrayToPointerDecay: 3774 return EvalVal(SubExpr, refVars, ParentDecl); 3775 3776 default: 3777 return 0; 3778 } 3779 } 3780 3781 case Stmt::MaterializeTemporaryExprClass: 3782 if (Expr *Result = EvalAddr( 3783 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 3784 refVars, ParentDecl)) 3785 return Result; 3786 3787 return E; 3788 3789 // Everything else: we simply don't reason about them. 3790 default: 3791 return NULL; 3792 } 3793} 3794 3795 3796/// EvalVal - This function is complements EvalAddr in the mutual recursion. 3797/// See the comments for EvalAddr for more details. 3798static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3799 Decl *ParentDecl) { 3800do { 3801 // We should only be called for evaluating non-pointer expressions, or 3802 // expressions with a pointer type that are not used as references but instead 3803 // are l-values (e.g., DeclRefExpr with a pointer type). 3804 3805 // Our "symbolic interpreter" is just a dispatch off the currently 3806 // viewed AST node. We then recursively traverse the AST by calling 3807 // EvalAddr and EvalVal appropriately. 3808 3809 E = E->IgnoreParens(); 3810 switch (E->getStmtClass()) { 3811 case Stmt::ImplicitCastExprClass: { 3812 ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E); 3813 if (IE->getValueKind() == VK_LValue) { 3814 E = IE->getSubExpr(); 3815 continue; 3816 } 3817 return NULL; 3818 } 3819 3820 case Stmt::ExprWithCleanupsClass: 3821 return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,ParentDecl); 3822 3823 case Stmt::DeclRefExprClass: { 3824 // When we hit a DeclRefExpr we are looking at code that refers to a 3825 // variable's name. If it's not a reference variable we check if it has 3826 // local storage within the function, and if so, return the expression. 3827 DeclRefExpr *DR = cast<DeclRefExpr>(E); 3828 3829 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) { 3830 // Check if it refers to itself, e.g. "int& i = i;". 3831 if (V == ParentDecl) 3832 return DR; 3833 3834 if (V->hasLocalStorage()) { 3835 if (!V->getType()->isReferenceType()) 3836 return DR; 3837 3838 // Reference variable, follow through to the expression that 3839 // it points to. 3840 if (V->hasInit()) { 3841 // Add the reference variable to the "trail". 3842 refVars.push_back(DR); 3843 return EvalVal(V->getInit(), refVars, V); 3844 } 3845 } 3846 } 3847 3848 return NULL; 3849 } 3850 3851 case Stmt::UnaryOperatorClass: { 3852 // The only unary operator that make sense to handle here 3853 // is Deref. All others don't resolve to a "name." This includes 3854 // handling all sorts of rvalues passed to a unary operator. 3855 UnaryOperator *U = cast<UnaryOperator>(E); 3856 3857 if (U->getOpcode() == UO_Deref) 3858 return EvalAddr(U->getSubExpr(), refVars, ParentDecl); 3859 3860 return NULL; 3861 } 3862 3863 case Stmt::ArraySubscriptExprClass: { 3864 // Array subscripts are potential references to data on the stack. We 3865 // retrieve the DeclRefExpr* for the array variable if it indeed 3866 // has local storage. 3867 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars,ParentDecl); 3868 } 3869 3870 case Stmt::ConditionalOperatorClass: { 3871 // For conditional operators we need to see if either the LHS or RHS are 3872 // non-NULL Expr's. If one is non-NULL, we return it. 3873 ConditionalOperator *C = cast<ConditionalOperator>(E); 3874 3875 // Handle the GNU extension for missing LHS. 3876 if (Expr *lhsExpr = C->getLHS()) 3877 if (Expr *LHS = EvalVal(lhsExpr, refVars, ParentDecl)) 3878 return LHS; 3879 3880 return EvalVal(C->getRHS(), refVars, ParentDecl); 3881 } 3882 3883 // Accesses to members are potential references to data on the stack. 3884 case Stmt::MemberExprClass: { 3885 MemberExpr *M = cast<MemberExpr>(E); 3886 3887 // Check for indirect access. We only want direct field accesses. 3888 if (M->isArrow()) 3889 return NULL; 3890 3891 // Check whether the member type is itself a reference, in which case 3892 // we're not going to refer to the member, but to what the member refers to. 3893 if (M->getMemberDecl()->getType()->isReferenceType()) 3894 return NULL; 3895 3896 return EvalVal(M->getBase(), refVars, ParentDecl); 3897 } 3898 3899 case Stmt::MaterializeTemporaryExprClass: 3900 if (Expr *Result = EvalVal( 3901 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 3902 refVars, ParentDecl)) 3903 return Result; 3904 3905 return E; 3906 3907 default: 3908 // Check that we don't return or take the address of a reference to a 3909 // temporary. This is only useful in C++. 3910 if (!E->isTypeDependent() && E->isRValue()) 3911 return E; 3912 3913 // Everything else: we simply don't reason about them. 3914 return NULL; 3915 } 3916} while (true); 3917} 3918 3919//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===// 3920 3921/// Check for comparisons of floating point operands using != and ==. 3922/// Issue a warning if these are no self-comparisons, as they are not likely 3923/// to do what the programmer intended. 3924void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) { 3925 Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts(); 3926 Expr* RightExprSansParen = RHS->IgnoreParenImpCasts(); 3927 3928 // Special case: check for x == x (which is OK). 3929 // Do not emit warnings for such cases. 3930 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen)) 3931 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen)) 3932 if (DRL->getDecl() == DRR->getDecl()) 3933 return; 3934 3935 3936 // Special case: check for comparisons against literals that can be exactly 3937 // represented by APFloat. In such cases, do not emit a warning. This 3938 // is a heuristic: often comparison against such literals are used to 3939 // detect if a value in a variable has not changed. This clearly can 3940 // lead to false negatives. 3941 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) { 3942 if (FLL->isExact()) 3943 return; 3944 } else 3945 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)) 3946 if (FLR->isExact()) 3947 return; 3948 3949 // Check for comparisons with builtin types. 3950 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen)) 3951 if (CL->isBuiltinCall()) 3952 return; 3953 3954 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen)) 3955 if (CR->isBuiltinCall()) 3956 return; 3957 3958 // Emit the diagnostic. 3959 Diag(Loc, diag::warn_floatingpoint_eq) 3960 << LHS->getSourceRange() << RHS->getSourceRange(); 3961} 3962 3963//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===// 3964//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===// 3965 3966namespace { 3967 3968/// Structure recording the 'active' range of an integer-valued 3969/// expression. 3970struct IntRange { 3971 /// The number of bits active in the int. 3972 unsigned Width; 3973 3974 /// True if the int is known not to have negative values. 3975 bool NonNegative; 3976 3977 IntRange(unsigned Width, bool NonNegative) 3978 : Width(Width), NonNegative(NonNegative) 3979 {} 3980 3981 /// Returns the range of the bool type. 3982 static IntRange forBoolType() { 3983 return IntRange(1, true); 3984 } 3985 3986 /// Returns the range of an opaque value of the given integral type. 3987 static IntRange forValueOfType(ASTContext &C, QualType T) { 3988 return forValueOfCanonicalType(C, 3989 T->getCanonicalTypeInternal().getTypePtr()); 3990 } 3991 3992 /// Returns the range of an opaque value of a canonical integral type. 3993 static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) { 3994 assert(T->isCanonicalUnqualified()); 3995 3996 if (const VectorType *VT = dyn_cast<VectorType>(T)) 3997 T = VT->getElementType().getTypePtr(); 3998 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 3999 T = CT->getElementType().getTypePtr(); 4000 4001 // For enum types, use the known bit width of the enumerators. 4002 if (const EnumType *ET = dyn_cast<EnumType>(T)) { 4003 EnumDecl *Enum = ET->getDecl(); 4004 if (!Enum->isCompleteDefinition()) 4005 return IntRange(C.getIntWidth(QualType(T, 0)), false); 4006 4007 unsigned NumPositive = Enum->getNumPositiveBits(); 4008 unsigned NumNegative = Enum->getNumNegativeBits(); 4009 4010 if (NumNegative == 0) 4011 return IntRange(NumPositive, true/*NonNegative*/); 4012 else 4013 return IntRange(std::max(NumPositive + 1, NumNegative), 4014 false/*NonNegative*/); 4015 } 4016 4017 const BuiltinType *BT = cast<BuiltinType>(T); 4018 assert(BT->isInteger()); 4019 4020 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 4021 } 4022 4023 /// Returns the "target" range of a canonical integral type, i.e. 4024 /// the range of values expressible in the type. 4025 /// 4026 /// This matches forValueOfCanonicalType except that enums have the 4027 /// full range of their type, not the range of their enumerators. 4028 static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) { 4029 assert(T->isCanonicalUnqualified()); 4030 4031 if (const VectorType *VT = dyn_cast<VectorType>(T)) 4032 T = VT->getElementType().getTypePtr(); 4033 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 4034 T = CT->getElementType().getTypePtr(); 4035 if (const EnumType *ET = dyn_cast<EnumType>(T)) 4036 T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr(); 4037 4038 const BuiltinType *BT = cast<BuiltinType>(T); 4039 assert(BT->isInteger()); 4040 4041 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 4042 } 4043 4044 /// Returns the supremum of two ranges: i.e. their conservative merge. 4045 static IntRange join(IntRange L, IntRange R) { 4046 return IntRange(std::max(L.Width, R.Width), 4047 L.NonNegative && R.NonNegative); 4048 } 4049 4050 /// Returns the infinum of two ranges: i.e. their aggressive merge. 4051 static IntRange meet(IntRange L, IntRange R) { 4052 return IntRange(std::min(L.Width, R.Width), 4053 L.NonNegative || R.NonNegative); 4054 } 4055}; 4056 4057static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, 4058 unsigned MaxWidth) { 4059 if (value.isSigned() && value.isNegative()) 4060 return IntRange(value.getMinSignedBits(), false); 4061 4062 if (value.getBitWidth() > MaxWidth) 4063 value = value.trunc(MaxWidth); 4064 4065 // isNonNegative() just checks the sign bit without considering 4066 // signedness. 4067 return IntRange(value.getActiveBits(), true); 4068} 4069 4070static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty, 4071 unsigned MaxWidth) { 4072 if (result.isInt()) 4073 return GetValueRange(C, result.getInt(), MaxWidth); 4074 4075 if (result.isVector()) { 4076 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth); 4077 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) { 4078 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth); 4079 R = IntRange::join(R, El); 4080 } 4081 return R; 4082 } 4083 4084 if (result.isComplexInt()) { 4085 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth); 4086 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth); 4087 return IntRange::join(R, I); 4088 } 4089 4090 // This can happen with lossless casts to intptr_t of "based" lvalues. 4091 // Assume it might use arbitrary bits. 4092 // FIXME: The only reason we need to pass the type in here is to get 4093 // the sign right on this one case. It would be nice if APValue 4094 // preserved this. 4095 assert(result.isLValue() || result.isAddrLabelDiff()); 4096 return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType()); 4097} 4098 4099/// Pseudo-evaluate the given integer expression, estimating the 4100/// range of values it might take. 4101/// 4102/// \param MaxWidth - the width to which the value will be truncated 4103static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) { 4104 E = E->IgnoreParens(); 4105 4106 // Try a full evaluation first. 4107 Expr::EvalResult result; 4108 if (E->EvaluateAsRValue(result, C)) 4109 return GetValueRange(C, result.Val, E->getType(), MaxWidth); 4110 4111 // I think we only want to look through implicit casts here; if the 4112 // user has an explicit widening cast, we should treat the value as 4113 // being of the new, wider type. 4114 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) { 4115 if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue) 4116 return GetExprRange(C, CE->getSubExpr(), MaxWidth); 4117 4118 IntRange OutputTypeRange = IntRange::forValueOfType(C, CE->getType()); 4119 4120 bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast); 4121 4122 // Assume that non-integer casts can span the full range of the type. 4123 if (!isIntegerCast) 4124 return OutputTypeRange; 4125 4126 IntRange SubRange 4127 = GetExprRange(C, CE->getSubExpr(), 4128 std::min(MaxWidth, OutputTypeRange.Width)); 4129 4130 // Bail out if the subexpr's range is as wide as the cast type. 4131 if (SubRange.Width >= OutputTypeRange.Width) 4132 return OutputTypeRange; 4133 4134 // Otherwise, we take the smaller width, and we're non-negative if 4135 // either the output type or the subexpr is. 4136 return IntRange(SubRange.Width, 4137 SubRange.NonNegative || OutputTypeRange.NonNegative); 4138 } 4139 4140 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 4141 // If we can fold the condition, just take that operand. 4142 bool CondResult; 4143 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C)) 4144 return GetExprRange(C, CondResult ? CO->getTrueExpr() 4145 : CO->getFalseExpr(), 4146 MaxWidth); 4147 4148 // Otherwise, conservatively merge. 4149 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth); 4150 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth); 4151 return IntRange::join(L, R); 4152 } 4153 4154 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 4155 switch (BO->getOpcode()) { 4156 4157 // Boolean-valued operations are single-bit and positive. 4158 case BO_LAnd: 4159 case BO_LOr: 4160 case BO_LT: 4161 case BO_GT: 4162 case BO_LE: 4163 case BO_GE: 4164 case BO_EQ: 4165 case BO_NE: 4166 return IntRange::forBoolType(); 4167 4168 // The type of the assignments is the type of the LHS, so the RHS 4169 // is not necessarily the same type. 4170 case BO_MulAssign: 4171 case BO_DivAssign: 4172 case BO_RemAssign: 4173 case BO_AddAssign: 4174 case BO_SubAssign: 4175 case BO_XorAssign: 4176 case BO_OrAssign: 4177 // TODO: bitfields? 4178 return IntRange::forValueOfType(C, E->getType()); 4179 4180 // Simple assignments just pass through the RHS, which will have 4181 // been coerced to the LHS type. 4182 case BO_Assign: 4183 // TODO: bitfields? 4184 return GetExprRange(C, BO->getRHS(), MaxWidth); 4185 4186 // Operations with opaque sources are black-listed. 4187 case BO_PtrMemD: 4188 case BO_PtrMemI: 4189 return IntRange::forValueOfType(C, E->getType()); 4190 4191 // Bitwise-and uses the *infinum* of the two source ranges. 4192 case BO_And: 4193 case BO_AndAssign: 4194 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth), 4195 GetExprRange(C, BO->getRHS(), MaxWidth)); 4196 4197 // Left shift gets black-listed based on a judgement call. 4198 case BO_Shl: 4199 // ...except that we want to treat '1 << (blah)' as logically 4200 // positive. It's an important idiom. 4201 if (IntegerLiteral *I 4202 = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) { 4203 if (I->getValue() == 1) { 4204 IntRange R = IntRange::forValueOfType(C, E->getType()); 4205 return IntRange(R.Width, /*NonNegative*/ true); 4206 } 4207 } 4208 // fallthrough 4209 4210 case BO_ShlAssign: 4211 return IntRange::forValueOfType(C, E->getType()); 4212 4213 // Right shift by a constant can narrow its left argument. 4214 case BO_Shr: 4215 case BO_ShrAssign: { 4216 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 4217 4218 // If the shift amount is a positive constant, drop the width by 4219 // that much. 4220 llvm::APSInt shift; 4221 if (BO->getRHS()->isIntegerConstantExpr(shift, C) && 4222 shift.isNonNegative()) { 4223 unsigned zext = shift.getZExtValue(); 4224 if (zext >= L.Width) 4225 L.Width = (L.NonNegative ? 0 : 1); 4226 else 4227 L.Width -= zext; 4228 } 4229 4230 return L; 4231 } 4232 4233 // Comma acts as its right operand. 4234 case BO_Comma: 4235 return GetExprRange(C, BO->getRHS(), MaxWidth); 4236 4237 // Black-list pointer subtractions. 4238 case BO_Sub: 4239 if (BO->getLHS()->getType()->isPointerType()) 4240 return IntRange::forValueOfType(C, E->getType()); 4241 break; 4242 4243 // The width of a division result is mostly determined by the size 4244 // of the LHS. 4245 case BO_Div: { 4246 // Don't 'pre-truncate' the operands. 4247 unsigned opWidth = C.getIntWidth(E->getType()); 4248 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 4249 4250 // If the divisor is constant, use that. 4251 llvm::APSInt divisor; 4252 if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) { 4253 unsigned log2 = divisor.logBase2(); // floor(log_2(divisor)) 4254 if (log2 >= L.Width) 4255 L.Width = (L.NonNegative ? 0 : 1); 4256 else 4257 L.Width = std::min(L.Width - log2, MaxWidth); 4258 return L; 4259 } 4260 4261 // Otherwise, just use the LHS's width. 4262 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 4263 return IntRange(L.Width, L.NonNegative && R.NonNegative); 4264 } 4265 4266 // The result of a remainder can't be larger than the result of 4267 // either side. 4268 case BO_Rem: { 4269 // Don't 'pre-truncate' the operands. 4270 unsigned opWidth = C.getIntWidth(E->getType()); 4271 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 4272 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 4273 4274 IntRange meet = IntRange::meet(L, R); 4275 meet.Width = std::min(meet.Width, MaxWidth); 4276 return meet; 4277 } 4278 4279 // The default behavior is okay for these. 4280 case BO_Mul: 4281 case BO_Add: 4282 case BO_Xor: 4283 case BO_Or: 4284 break; 4285 } 4286 4287 // The default case is to treat the operation as if it were closed 4288 // on the narrowest type that encompasses both operands. 4289 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 4290 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth); 4291 return IntRange::join(L, R); 4292 } 4293 4294 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 4295 switch (UO->getOpcode()) { 4296 // Boolean-valued operations are white-listed. 4297 case UO_LNot: 4298 return IntRange::forBoolType(); 4299 4300 // Operations with opaque sources are black-listed. 4301 case UO_Deref: 4302 case UO_AddrOf: // should be impossible 4303 return IntRange::forValueOfType(C, E->getType()); 4304 4305 default: 4306 return GetExprRange(C, UO->getSubExpr(), MaxWidth); 4307 } 4308 } 4309 4310 if (dyn_cast<OffsetOfExpr>(E)) { 4311 IntRange::forValueOfType(C, E->getType()); 4312 } 4313 4314 if (FieldDecl *BitField = E->getSourceBitField()) 4315 return IntRange(BitField->getBitWidthValue(C), 4316 BitField->getType()->isUnsignedIntegerOrEnumerationType()); 4317 4318 return IntRange::forValueOfType(C, E->getType()); 4319} 4320 4321static IntRange GetExprRange(ASTContext &C, Expr *E) { 4322 return GetExprRange(C, E, C.getIntWidth(E->getType())); 4323} 4324 4325/// Checks whether the given value, which currently has the given 4326/// source semantics, has the same value when coerced through the 4327/// target semantics. 4328static bool IsSameFloatAfterCast(const llvm::APFloat &value, 4329 const llvm::fltSemantics &Src, 4330 const llvm::fltSemantics &Tgt) { 4331 llvm::APFloat truncated = value; 4332 4333 bool ignored; 4334 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored); 4335 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored); 4336 4337 return truncated.bitwiseIsEqual(value); 4338} 4339 4340/// Checks whether the given value, which currently has the given 4341/// source semantics, has the same value when coerced through the 4342/// target semantics. 4343/// 4344/// The value might be a vector of floats (or a complex number). 4345static bool IsSameFloatAfterCast(const APValue &value, 4346 const llvm::fltSemantics &Src, 4347 const llvm::fltSemantics &Tgt) { 4348 if (value.isFloat()) 4349 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt); 4350 4351 if (value.isVector()) { 4352 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i) 4353 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt)) 4354 return false; 4355 return true; 4356 } 4357 4358 assert(value.isComplexFloat()); 4359 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) && 4360 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt)); 4361} 4362 4363static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC); 4364 4365static bool IsZero(Sema &S, Expr *E) { 4366 // Suppress cases where we are comparing against an enum constant. 4367 if (const DeclRefExpr *DR = 4368 dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts())) 4369 if (isa<EnumConstantDecl>(DR->getDecl())) 4370 return false; 4371 4372 // Suppress cases where the '0' value is expanded from a macro. 4373 if (E->getLocStart().isMacroID()) 4374 return false; 4375 4376 llvm::APSInt Value; 4377 return E->isIntegerConstantExpr(Value, S.Context) && Value == 0; 4378} 4379 4380static bool HasEnumType(Expr *E) { 4381 // Strip off implicit integral promotions. 4382 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 4383 if (ICE->getCastKind() != CK_IntegralCast && 4384 ICE->getCastKind() != CK_NoOp) 4385 break; 4386 E = ICE->getSubExpr(); 4387 } 4388 4389 return E->getType()->isEnumeralType(); 4390} 4391 4392static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) { 4393 BinaryOperatorKind op = E->getOpcode(); 4394 if (E->isValueDependent()) 4395 return; 4396 4397 if (op == BO_LT && IsZero(S, E->getRHS())) { 4398 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 4399 << "< 0" << "false" << HasEnumType(E->getLHS()) 4400 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4401 } else if (op == BO_GE && IsZero(S, E->getRHS())) { 4402 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 4403 << ">= 0" << "true" << HasEnumType(E->getLHS()) 4404 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4405 } else if (op == BO_GT && IsZero(S, E->getLHS())) { 4406 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 4407 << "0 >" << "false" << HasEnumType(E->getRHS()) 4408 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4409 } else if (op == BO_LE && IsZero(S, E->getLHS())) { 4410 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 4411 << "0 <=" << "true" << HasEnumType(E->getRHS()) 4412 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4413 } 4414} 4415 4416static void DiagnoseOutOfRangeComparison(Sema &S, BinaryOperator *E, 4417 Expr *Constant, Expr *Other, 4418 llvm::APSInt Value, 4419 bool RhsConstant) { 4420 // 0 values are handled later by CheckTrivialUnsignedComparison(). 4421 if (Value == 0) 4422 return; 4423 4424 BinaryOperatorKind op = E->getOpcode(); 4425 QualType OtherT = Other->getType(); 4426 QualType ConstantT = Constant->getType(); 4427 QualType CommonT = E->getLHS()->getType(); 4428 if (S.Context.hasSameUnqualifiedType(OtherT, ConstantT)) 4429 return; 4430 assert((OtherT->isIntegerType() && ConstantT->isIntegerType()) 4431 && "comparison with non-integer type"); 4432 4433 bool ConstantSigned = ConstantT->isSignedIntegerType(); 4434 bool CommonSigned = CommonT->isSignedIntegerType(); 4435 4436 bool EqualityOnly = false; 4437 4438 // TODO: Investigate using GetExprRange() to get tighter bounds on 4439 // on the bit ranges. 4440 IntRange OtherRange = IntRange::forValueOfType(S.Context, OtherT); 4441 unsigned OtherWidth = OtherRange.Width; 4442 4443 if (CommonSigned) { 4444 // The common type is signed, therefore no signed to unsigned conversion. 4445 if (!OtherRange.NonNegative) { 4446 // Check that the constant is representable in type OtherT. 4447 if (ConstantSigned) { 4448 if (OtherWidth >= Value.getMinSignedBits()) 4449 return; 4450 } else { // !ConstantSigned 4451 if (OtherWidth >= Value.getActiveBits() + 1) 4452 return; 4453 } 4454 } else { // !OtherSigned 4455 // Check that the constant is representable in type OtherT. 4456 // Negative values are out of range. 4457 if (ConstantSigned) { 4458 if (Value.isNonNegative() && OtherWidth >= Value.getActiveBits()) 4459 return; 4460 } else { // !ConstantSigned 4461 if (OtherWidth >= Value.getActiveBits()) 4462 return; 4463 } 4464 } 4465 } else { // !CommonSigned 4466 if (OtherRange.NonNegative) { 4467 if (OtherWidth >= Value.getActiveBits()) 4468 return; 4469 } else if (!OtherRange.NonNegative && !ConstantSigned) { 4470 // Check to see if the constant is representable in OtherT. 4471 if (OtherWidth > Value.getActiveBits()) 4472 return; 4473 // Check to see if the constant is equivalent to a negative value 4474 // cast to CommonT. 4475 if (S.Context.getIntWidth(ConstantT) == S.Context.getIntWidth(CommonT) && 4476 Value.isNegative() && Value.getMinSignedBits() <= OtherWidth) 4477 return; 4478 // The constant value rests between values that OtherT can represent after 4479 // conversion. Relational comparison still works, but equality 4480 // comparisons will be tautological. 4481 EqualityOnly = true; 4482 } else { // OtherSigned && ConstantSigned 4483 assert(0 && "Two signed types converted to unsigned types."); 4484 } 4485 } 4486 4487 bool PositiveConstant = !ConstantSigned || Value.isNonNegative(); 4488 4489 bool IsTrue = true; 4490 if (op == BO_EQ || op == BO_NE) { 4491 IsTrue = op == BO_NE; 4492 } else if (EqualityOnly) { 4493 return; 4494 } else if (RhsConstant) { 4495 if (op == BO_GT || op == BO_GE) 4496 IsTrue = !PositiveConstant; 4497 else // op == BO_LT || op == BO_LE 4498 IsTrue = PositiveConstant; 4499 } else { 4500 if (op == BO_LT || op == BO_LE) 4501 IsTrue = !PositiveConstant; 4502 else // op == BO_GT || op == BO_GE 4503 IsTrue = PositiveConstant; 4504 } 4505 4506 // If this is a comparison to an enum constant, include that 4507 // constant in the diagnostic. 4508 const EnumConstantDecl *ED = 0; 4509 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Constant)) 4510 ED = dyn_cast<EnumConstantDecl>(DR->getDecl()); 4511 4512 SmallString<64> PrettySourceValue; 4513 llvm::raw_svector_ostream OS(PrettySourceValue); 4514 if (ED) 4515 OS << '\'' << *ED << "' (" << Value << ")"; 4516 else 4517 OS << Value; 4518 4519 S.Diag(E->getOperatorLoc(), diag::warn_out_of_range_compare) 4520 << OS.str() << OtherT << IsTrue 4521 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4522} 4523 4524/// Analyze the operands of the given comparison. Implements the 4525/// fallback case from AnalyzeComparison. 4526static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) { 4527 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 4528 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 4529} 4530 4531/// \brief Implements -Wsign-compare. 4532/// 4533/// \param E the binary operator to check for warnings 4534static void AnalyzeComparison(Sema &S, BinaryOperator *E) { 4535 // The type the comparison is being performed in. 4536 QualType T = E->getLHS()->getType(); 4537 assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType()) 4538 && "comparison with mismatched types"); 4539 if (E->isValueDependent()) 4540 return AnalyzeImpConvsInComparison(S, E); 4541 4542 Expr *LHS = E->getLHS()->IgnoreParenImpCasts(); 4543 Expr *RHS = E->getRHS()->IgnoreParenImpCasts(); 4544 4545 bool IsComparisonConstant = false; 4546 4547 // Check whether an integer constant comparison results in a value 4548 // of 'true' or 'false'. 4549 if (T->isIntegralType(S.Context)) { 4550 llvm::APSInt RHSValue; 4551 bool IsRHSIntegralLiteral = 4552 RHS->isIntegerConstantExpr(RHSValue, S.Context); 4553 llvm::APSInt LHSValue; 4554 bool IsLHSIntegralLiteral = 4555 LHS->isIntegerConstantExpr(LHSValue, S.Context); 4556 if (IsRHSIntegralLiteral && !IsLHSIntegralLiteral) 4557 DiagnoseOutOfRangeComparison(S, E, RHS, LHS, RHSValue, true); 4558 else if (!IsRHSIntegralLiteral && IsLHSIntegralLiteral) 4559 DiagnoseOutOfRangeComparison(S, E, LHS, RHS, LHSValue, false); 4560 else 4561 IsComparisonConstant = 4562 (IsRHSIntegralLiteral && IsLHSIntegralLiteral); 4563 } else if (!T->hasUnsignedIntegerRepresentation()) 4564 IsComparisonConstant = E->isIntegerConstantExpr(S.Context); 4565 4566 // We don't do anything special if this isn't an unsigned integral 4567 // comparison: we're only interested in integral comparisons, and 4568 // signed comparisons only happen in cases we don't care to warn about. 4569 // 4570 // We also don't care about value-dependent expressions or expressions 4571 // whose result is a constant. 4572 if (!T->hasUnsignedIntegerRepresentation() || IsComparisonConstant) 4573 return AnalyzeImpConvsInComparison(S, E); 4574 4575 // Check to see if one of the (unmodified) operands is of different 4576 // signedness. 4577 Expr *signedOperand, *unsignedOperand; 4578 if (LHS->getType()->hasSignedIntegerRepresentation()) { 4579 assert(!RHS->getType()->hasSignedIntegerRepresentation() && 4580 "unsigned comparison between two signed integer expressions?"); 4581 signedOperand = LHS; 4582 unsignedOperand = RHS; 4583 } else if (RHS->getType()->hasSignedIntegerRepresentation()) { 4584 signedOperand = RHS; 4585 unsignedOperand = LHS; 4586 } else { 4587 CheckTrivialUnsignedComparison(S, E); 4588 return AnalyzeImpConvsInComparison(S, E); 4589 } 4590 4591 // Otherwise, calculate the effective range of the signed operand. 4592 IntRange signedRange = GetExprRange(S.Context, signedOperand); 4593 4594 // Go ahead and analyze implicit conversions in the operands. Note 4595 // that we skip the implicit conversions on both sides. 4596 AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc()); 4597 AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc()); 4598 4599 // If the signed range is non-negative, -Wsign-compare won't fire, 4600 // but we should still check for comparisons which are always true 4601 // or false. 4602 if (signedRange.NonNegative) 4603 return CheckTrivialUnsignedComparison(S, E); 4604 4605 // For (in)equality comparisons, if the unsigned operand is a 4606 // constant which cannot collide with a overflowed signed operand, 4607 // then reinterpreting the signed operand as unsigned will not 4608 // change the result of the comparison. 4609 if (E->isEqualityOp()) { 4610 unsigned comparisonWidth = S.Context.getIntWidth(T); 4611 IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand); 4612 4613 // We should never be unable to prove that the unsigned operand is 4614 // non-negative. 4615 assert(unsignedRange.NonNegative && "unsigned range includes negative?"); 4616 4617 if (unsignedRange.Width < comparisonWidth) 4618 return; 4619 } 4620 4621 S.DiagRuntimeBehavior(E->getOperatorLoc(), E, 4622 S.PDiag(diag::warn_mixed_sign_comparison) 4623 << LHS->getType() << RHS->getType() 4624 << LHS->getSourceRange() << RHS->getSourceRange()); 4625} 4626 4627/// Analyzes an attempt to assign the given value to a bitfield. 4628/// 4629/// Returns true if there was something fishy about the attempt. 4630static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init, 4631 SourceLocation InitLoc) { 4632 assert(Bitfield->isBitField()); 4633 if (Bitfield->isInvalidDecl()) 4634 return false; 4635 4636 // White-list bool bitfields. 4637 if (Bitfield->getType()->isBooleanType()) 4638 return false; 4639 4640 // Ignore value- or type-dependent expressions. 4641 if (Bitfield->getBitWidth()->isValueDependent() || 4642 Bitfield->getBitWidth()->isTypeDependent() || 4643 Init->isValueDependent() || 4644 Init->isTypeDependent()) 4645 return false; 4646 4647 Expr *OriginalInit = Init->IgnoreParenImpCasts(); 4648 4649 llvm::APSInt Value; 4650 if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects)) 4651 return false; 4652 4653 unsigned OriginalWidth = Value.getBitWidth(); 4654 unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context); 4655 4656 if (OriginalWidth <= FieldWidth) 4657 return false; 4658 4659 // Compute the value which the bitfield will contain. 4660 llvm::APSInt TruncatedValue = Value.trunc(FieldWidth); 4661 TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType()); 4662 4663 // Check whether the stored value is equal to the original value. 4664 TruncatedValue = TruncatedValue.extend(OriginalWidth); 4665 if (llvm::APSInt::isSameValue(Value, TruncatedValue)) 4666 return false; 4667 4668 // Special-case bitfields of width 1: booleans are naturally 0/1, and 4669 // therefore don't strictly fit into a signed bitfield of width 1. 4670 if (FieldWidth == 1 && Value == 1) 4671 return false; 4672 4673 std::string PrettyValue = Value.toString(10); 4674 std::string PrettyTrunc = TruncatedValue.toString(10); 4675 4676 S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant) 4677 << PrettyValue << PrettyTrunc << OriginalInit->getType() 4678 << Init->getSourceRange(); 4679 4680 return true; 4681} 4682 4683/// Analyze the given simple or compound assignment for warning-worthy 4684/// operations. 4685static void AnalyzeAssignment(Sema &S, BinaryOperator *E) { 4686 // Just recurse on the LHS. 4687 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 4688 4689 // We want to recurse on the RHS as normal unless we're assigning to 4690 // a bitfield. 4691 if (FieldDecl *Bitfield = E->getLHS()->getSourceBitField()) { 4692 if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(), 4693 E->getOperatorLoc())) { 4694 // Recurse, ignoring any implicit conversions on the RHS. 4695 return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(), 4696 E->getOperatorLoc()); 4697 } 4698 } 4699 4700 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 4701} 4702 4703/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 4704static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T, 4705 SourceLocation CContext, unsigned diag, 4706 bool pruneControlFlow = false) { 4707 if (pruneControlFlow) { 4708 S.DiagRuntimeBehavior(E->getExprLoc(), E, 4709 S.PDiag(diag) 4710 << SourceType << T << E->getSourceRange() 4711 << SourceRange(CContext)); 4712 return; 4713 } 4714 S.Diag(E->getExprLoc(), diag) 4715 << SourceType << T << E->getSourceRange() << SourceRange(CContext); 4716} 4717 4718/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 4719static void DiagnoseImpCast(Sema &S, Expr *E, QualType T, 4720 SourceLocation CContext, unsigned diag, 4721 bool pruneControlFlow = false) { 4722 DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow); 4723} 4724 4725/// Diagnose an implicit cast from a literal expression. Does not warn when the 4726/// cast wouldn't lose information. 4727void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T, 4728 SourceLocation CContext) { 4729 // Try to convert the literal exactly to an integer. If we can, don't warn. 4730 bool isExact = false; 4731 const llvm::APFloat &Value = FL->getValue(); 4732 llvm::APSInt IntegerValue(S.Context.getIntWidth(T), 4733 T->hasUnsignedIntegerRepresentation()); 4734 if (Value.convertToInteger(IntegerValue, 4735 llvm::APFloat::rmTowardZero, &isExact) 4736 == llvm::APFloat::opOK && isExact) 4737 return; 4738 4739 SmallString<16> PrettySourceValue; 4740 Value.toString(PrettySourceValue); 4741 SmallString<16> PrettyTargetValue; 4742 if (T->isSpecificBuiltinType(BuiltinType::Bool)) 4743 PrettyTargetValue = IntegerValue == 0 ? "false" : "true"; 4744 else 4745 IntegerValue.toString(PrettyTargetValue); 4746 4747 S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer) 4748 << FL->getType() << T.getUnqualifiedType() << PrettySourceValue 4749 << PrettyTargetValue << FL->getSourceRange() << SourceRange(CContext); 4750} 4751 4752std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) { 4753 if (!Range.Width) return "0"; 4754 4755 llvm::APSInt ValueInRange = Value; 4756 ValueInRange.setIsSigned(!Range.NonNegative); 4757 ValueInRange = ValueInRange.trunc(Range.Width); 4758 return ValueInRange.toString(10); 4759} 4760 4761static bool IsImplicitBoolFloatConversion(Sema &S, Expr *Ex, bool ToBool) { 4762 if (!isa<ImplicitCastExpr>(Ex)) 4763 return false; 4764 4765 Expr *InnerE = Ex->IgnoreParenImpCasts(); 4766 const Type *Target = S.Context.getCanonicalType(Ex->getType()).getTypePtr(); 4767 const Type *Source = 4768 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 4769 if (Target->isDependentType()) 4770 return false; 4771 4772 const BuiltinType *FloatCandidateBT = 4773 dyn_cast<BuiltinType>(ToBool ? Source : Target); 4774 const Type *BoolCandidateType = ToBool ? Target : Source; 4775 4776 return (BoolCandidateType->isSpecificBuiltinType(BuiltinType::Bool) && 4777 FloatCandidateBT && (FloatCandidateBT->isFloatingPoint())); 4778} 4779 4780void CheckImplicitArgumentConversions(Sema &S, CallExpr *TheCall, 4781 SourceLocation CC) { 4782 unsigned NumArgs = TheCall->getNumArgs(); 4783 for (unsigned i = 0; i < NumArgs; ++i) { 4784 Expr *CurrA = TheCall->getArg(i); 4785 if (!IsImplicitBoolFloatConversion(S, CurrA, true)) 4786 continue; 4787 4788 bool IsSwapped = ((i > 0) && 4789 IsImplicitBoolFloatConversion(S, TheCall->getArg(i - 1), false)); 4790 IsSwapped |= ((i < (NumArgs - 1)) && 4791 IsImplicitBoolFloatConversion(S, TheCall->getArg(i + 1), false)); 4792 if (IsSwapped) { 4793 // Warn on this floating-point to bool conversion. 4794 DiagnoseImpCast(S, CurrA->IgnoreParenImpCasts(), 4795 CurrA->getType(), CC, 4796 diag::warn_impcast_floating_point_to_bool); 4797 } 4798 } 4799} 4800 4801void CheckImplicitConversion(Sema &S, Expr *E, QualType T, 4802 SourceLocation CC, bool *ICContext = 0) { 4803 if (E->isTypeDependent() || E->isValueDependent()) return; 4804 4805 const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr(); 4806 const Type *Target = S.Context.getCanonicalType(T).getTypePtr(); 4807 if (Source == Target) return; 4808 if (Target->isDependentType()) return; 4809 4810 // If the conversion context location is invalid don't complain. We also 4811 // don't want to emit a warning if the issue occurs from the expansion of 4812 // a system macro. The problem is that 'getSpellingLoc()' is slow, so we 4813 // delay this check as long as possible. Once we detect we are in that 4814 // scenario, we just return. 4815 if (CC.isInvalid()) 4816 return; 4817 4818 // Diagnose implicit casts to bool. 4819 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) { 4820 if (isa<StringLiteral>(E)) 4821 // Warn on string literal to bool. Checks for string literals in logical 4822 // expressions, for instances, assert(0 && "error here"), is prevented 4823 // by a check in AnalyzeImplicitConversions(). 4824 return DiagnoseImpCast(S, E, T, CC, 4825 diag::warn_impcast_string_literal_to_bool); 4826 if (Source->isFunctionType()) { 4827 // Warn on function to bool. Checks free functions and static member 4828 // functions. Weakly imported functions are excluded from the check, 4829 // since it's common to test their value to check whether the linker 4830 // found a definition for them. 4831 ValueDecl *D = 0; 4832 if (DeclRefExpr* R = dyn_cast<DeclRefExpr>(E)) { 4833 D = R->getDecl(); 4834 } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) { 4835 D = M->getMemberDecl(); 4836 } 4837 4838 if (D && !D->isWeak()) { 4839 if (FunctionDecl* F = dyn_cast<FunctionDecl>(D)) { 4840 S.Diag(E->getExprLoc(), diag::warn_impcast_function_to_bool) 4841 << F << E->getSourceRange() << SourceRange(CC); 4842 S.Diag(E->getExprLoc(), diag::note_function_to_bool_silence) 4843 << FixItHint::CreateInsertion(E->getExprLoc(), "&"); 4844 QualType ReturnType; 4845 UnresolvedSet<4> NonTemplateOverloads; 4846 S.isExprCallable(*E, ReturnType, NonTemplateOverloads); 4847 if (!ReturnType.isNull() 4848 && ReturnType->isSpecificBuiltinType(BuiltinType::Bool)) 4849 S.Diag(E->getExprLoc(), diag::note_function_to_bool_call) 4850 << FixItHint::CreateInsertion( 4851 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()), "()"); 4852 return; 4853 } 4854 } 4855 } 4856 } 4857 4858 // Strip vector types. 4859 if (isa<VectorType>(Source)) { 4860 if (!isa<VectorType>(Target)) { 4861 if (S.SourceMgr.isInSystemMacro(CC)) 4862 return; 4863 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar); 4864 } 4865 4866 // If the vector cast is cast between two vectors of the same size, it is 4867 // a bitcast, not a conversion. 4868 if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target)) 4869 return; 4870 4871 Source = cast<VectorType>(Source)->getElementType().getTypePtr(); 4872 Target = cast<VectorType>(Target)->getElementType().getTypePtr(); 4873 } 4874 4875 // Strip complex types. 4876 if (isa<ComplexType>(Source)) { 4877 if (!isa<ComplexType>(Target)) { 4878 if (S.SourceMgr.isInSystemMacro(CC)) 4879 return; 4880 4881 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar); 4882 } 4883 4884 Source = cast<ComplexType>(Source)->getElementType().getTypePtr(); 4885 Target = cast<ComplexType>(Target)->getElementType().getTypePtr(); 4886 } 4887 4888 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source); 4889 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target); 4890 4891 // If the source is floating point... 4892 if (SourceBT && SourceBT->isFloatingPoint()) { 4893 // ...and the target is floating point... 4894 if (TargetBT && TargetBT->isFloatingPoint()) { 4895 // ...then warn if we're dropping FP rank. 4896 4897 // Builtin FP kinds are ordered by increasing FP rank. 4898 if (SourceBT->getKind() > TargetBT->getKind()) { 4899 // Don't warn about float constants that are precisely 4900 // representable in the target type. 4901 Expr::EvalResult result; 4902 if (E->EvaluateAsRValue(result, S.Context)) { 4903 // Value might be a float, a float vector, or a float complex. 4904 if (IsSameFloatAfterCast(result.Val, 4905 S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)), 4906 S.Context.getFloatTypeSemantics(QualType(SourceBT, 0)))) 4907 return; 4908 } 4909 4910 if (S.SourceMgr.isInSystemMacro(CC)) 4911 return; 4912 4913 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision); 4914 } 4915 return; 4916 } 4917 4918 // If the target is integral, always warn. 4919 if (TargetBT && TargetBT->isInteger()) { 4920 if (S.SourceMgr.isInSystemMacro(CC)) 4921 return; 4922 4923 Expr *InnerE = E->IgnoreParenImpCasts(); 4924 // We also want to warn on, e.g., "int i = -1.234" 4925 if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE)) 4926 if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus) 4927 InnerE = UOp->getSubExpr()->IgnoreParenImpCasts(); 4928 4929 if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) { 4930 DiagnoseFloatingLiteralImpCast(S, FL, T, CC); 4931 } else { 4932 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer); 4933 } 4934 } 4935 4936 // If the target is bool, warn if expr is a function or method call. 4937 if (Target->isSpecificBuiltinType(BuiltinType::Bool) && 4938 isa<CallExpr>(E)) { 4939 // Check last argument of function call to see if it is an 4940 // implicit cast from a type matching the type the result 4941 // is being cast to. 4942 CallExpr *CEx = cast<CallExpr>(E); 4943 unsigned NumArgs = CEx->getNumArgs(); 4944 if (NumArgs > 0) { 4945 Expr *LastA = CEx->getArg(NumArgs - 1); 4946 Expr *InnerE = LastA->IgnoreParenImpCasts(); 4947 const Type *InnerType = 4948 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 4949 if (isa<ImplicitCastExpr>(LastA) && (InnerType == Target)) { 4950 // Warn on this floating-point to bool conversion 4951 DiagnoseImpCast(S, E, T, CC, 4952 diag::warn_impcast_floating_point_to_bool); 4953 } 4954 } 4955 } 4956 return; 4957 } 4958 4959 if ((E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull) 4960 == Expr::NPCK_GNUNull) && !Target->isAnyPointerType() 4961 && !Target->isBlockPointerType() && !Target->isMemberPointerType() 4962 && Target->isScalarType() && !Target->isNullPtrType()) { 4963 SourceLocation Loc = E->getSourceRange().getBegin(); 4964 if (Loc.isMacroID()) 4965 Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first; 4966 if (!Loc.isMacroID() || CC.isMacroID()) 4967 S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer) 4968 << T << clang::SourceRange(CC) 4969 << FixItHint::CreateReplacement(Loc, S.getFixItZeroLiteralForType(T)); 4970 } 4971 4972 if (!Source->isIntegerType() || !Target->isIntegerType()) 4973 return; 4974 4975 // TODO: remove this early return once the false positives for constant->bool 4976 // in templates, macros, etc, are reduced or removed. 4977 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) 4978 return; 4979 4980 IntRange SourceRange = GetExprRange(S.Context, E); 4981 IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target); 4982 4983 if (SourceRange.Width > TargetRange.Width) { 4984 // If the source is a constant, use a default-on diagnostic. 4985 // TODO: this should happen for bitfield stores, too. 4986 llvm::APSInt Value(32); 4987 if (E->isIntegerConstantExpr(Value, S.Context)) { 4988 if (S.SourceMgr.isInSystemMacro(CC)) 4989 return; 4990 4991 std::string PrettySourceValue = Value.toString(10); 4992 std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange); 4993 4994 S.DiagRuntimeBehavior(E->getExprLoc(), E, 4995 S.PDiag(diag::warn_impcast_integer_precision_constant) 4996 << PrettySourceValue << PrettyTargetValue 4997 << E->getType() << T << E->getSourceRange() 4998 << clang::SourceRange(CC)); 4999 return; 5000 } 5001 5002 // People want to build with -Wshorten-64-to-32 and not -Wconversion. 5003 if (S.SourceMgr.isInSystemMacro(CC)) 5004 return; 5005 5006 if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64) 5007 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32, 5008 /* pruneControlFlow */ true); 5009 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision); 5010 } 5011 5012 if ((TargetRange.NonNegative && !SourceRange.NonNegative) || 5013 (!TargetRange.NonNegative && SourceRange.NonNegative && 5014 SourceRange.Width == TargetRange.Width)) { 5015 5016 if (S.SourceMgr.isInSystemMacro(CC)) 5017 return; 5018 5019 unsigned DiagID = diag::warn_impcast_integer_sign; 5020 5021 // Traditionally, gcc has warned about this under -Wsign-compare. 5022 // We also want to warn about it in -Wconversion. 5023 // So if -Wconversion is off, use a completely identical diagnostic 5024 // in the sign-compare group. 5025 // The conditional-checking code will 5026 if (ICContext) { 5027 DiagID = diag::warn_impcast_integer_sign_conditional; 5028 *ICContext = true; 5029 } 5030 5031 return DiagnoseImpCast(S, E, T, CC, DiagID); 5032 } 5033 5034 // Diagnose conversions between different enumeration types. 5035 // In C, we pretend that the type of an EnumConstantDecl is its enumeration 5036 // type, to give us better diagnostics. 5037 QualType SourceType = E->getType(); 5038 if (!S.getLangOpts().CPlusPlus) { 5039 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 5040 if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) { 5041 EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext()); 5042 SourceType = S.Context.getTypeDeclType(Enum); 5043 Source = S.Context.getCanonicalType(SourceType).getTypePtr(); 5044 } 5045 } 5046 5047 if (const EnumType *SourceEnum = Source->getAs<EnumType>()) 5048 if (const EnumType *TargetEnum = Target->getAs<EnumType>()) 5049 if (SourceEnum->getDecl()->hasNameForLinkage() && 5050 TargetEnum->getDecl()->hasNameForLinkage() && 5051 SourceEnum != TargetEnum) { 5052 if (S.SourceMgr.isInSystemMacro(CC)) 5053 return; 5054 5055 return DiagnoseImpCast(S, E, SourceType, T, CC, 5056 diag::warn_impcast_different_enum_types); 5057 } 5058 5059 return; 5060} 5061 5062void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 5063 SourceLocation CC, QualType T); 5064 5065void CheckConditionalOperand(Sema &S, Expr *E, QualType T, 5066 SourceLocation CC, bool &ICContext) { 5067 E = E->IgnoreParenImpCasts(); 5068 5069 if (isa<ConditionalOperator>(E)) 5070 return CheckConditionalOperator(S, cast<ConditionalOperator>(E), CC, T); 5071 5072 AnalyzeImplicitConversions(S, E, CC); 5073 if (E->getType() != T) 5074 return CheckImplicitConversion(S, E, T, CC, &ICContext); 5075 return; 5076} 5077 5078void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 5079 SourceLocation CC, QualType T) { 5080 AnalyzeImplicitConversions(S, E->getCond(), CC); 5081 5082 bool Suspicious = false; 5083 CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious); 5084 CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious); 5085 5086 // If -Wconversion would have warned about either of the candidates 5087 // for a signedness conversion to the context type... 5088 if (!Suspicious) return; 5089 5090 // ...but it's currently ignored... 5091 if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional, 5092 CC)) 5093 return; 5094 5095 // ...then check whether it would have warned about either of the 5096 // candidates for a signedness conversion to the condition type. 5097 if (E->getType() == T) return; 5098 5099 Suspicious = false; 5100 CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(), 5101 E->getType(), CC, &Suspicious); 5102 if (!Suspicious) 5103 CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(), 5104 E->getType(), CC, &Suspicious); 5105} 5106 5107/// AnalyzeImplicitConversions - Find and report any interesting 5108/// implicit conversions in the given expression. There are a couple 5109/// of competing diagnostics here, -Wconversion and -Wsign-compare. 5110void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) { 5111 QualType T = OrigE->getType(); 5112 Expr *E = OrigE->IgnoreParenImpCasts(); 5113 5114 if (E->isTypeDependent() || E->isValueDependent()) 5115 return; 5116 5117 // For conditional operators, we analyze the arguments as if they 5118 // were being fed directly into the output. 5119 if (isa<ConditionalOperator>(E)) { 5120 ConditionalOperator *CO = cast<ConditionalOperator>(E); 5121 CheckConditionalOperator(S, CO, CC, T); 5122 return; 5123 } 5124 5125 // Check implicit argument conversions for function calls. 5126 if (CallExpr *Call = dyn_cast<CallExpr>(E)) 5127 CheckImplicitArgumentConversions(S, Call, CC); 5128 5129 // Go ahead and check any implicit conversions we might have skipped. 5130 // The non-canonical typecheck is just an optimization; 5131 // CheckImplicitConversion will filter out dead implicit conversions. 5132 if (E->getType() != T) 5133 CheckImplicitConversion(S, E, T, CC); 5134 5135 // Now continue drilling into this expression. 5136 5137 if (PseudoObjectExpr * POE = dyn_cast<PseudoObjectExpr>(E)) { 5138 Expr *Result = POE->getResultExpr(); 5139 if (const OpaqueValueExpr *OVE = dyn_cast_or_null<OpaqueValueExpr>(Result)) 5140 return AnalyzeImplicitConversions(S, OVE->getSourceExpr(), CC); 5141 } 5142 5143 // Skip past explicit casts. 5144 if (isa<ExplicitCastExpr>(E)) { 5145 E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts(); 5146 return AnalyzeImplicitConversions(S, E, CC); 5147 } 5148 5149 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 5150 // Do a somewhat different check with comparison operators. 5151 if (BO->isComparisonOp()) 5152 return AnalyzeComparison(S, BO); 5153 5154 // And with simple assignments. 5155 if (BO->getOpcode() == BO_Assign) 5156 return AnalyzeAssignment(S, BO); 5157 } 5158 5159 // These break the otherwise-useful invariant below. Fortunately, 5160 // we don't really need to recurse into them, because any internal 5161 // expressions should have been analyzed already when they were 5162 // built into statements. 5163 if (isa<StmtExpr>(E)) return; 5164 5165 // Don't descend into unevaluated contexts. 5166 if (isa<UnaryExprOrTypeTraitExpr>(E)) return; 5167 5168 // Now just recurse over the expression's children. 5169 CC = E->getExprLoc(); 5170 BinaryOperator *BO = dyn_cast<BinaryOperator>(E); 5171 bool IsLogicalOperator = BO && BO->isLogicalOp(); 5172 for (Stmt::child_range I = E->children(); I; ++I) { 5173 Expr *ChildExpr = dyn_cast_or_null<Expr>(*I); 5174 if (!ChildExpr) 5175 continue; 5176 5177 if (IsLogicalOperator && 5178 isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts())) 5179 // Ignore checking string literals that are in logical operators. 5180 continue; 5181 AnalyzeImplicitConversions(S, ChildExpr, CC); 5182 } 5183} 5184 5185} // end anonymous namespace 5186 5187/// Diagnoses "dangerous" implicit conversions within the given 5188/// expression (which is a full expression). Implements -Wconversion 5189/// and -Wsign-compare. 5190/// 5191/// \param CC the "context" location of the implicit conversion, i.e. 5192/// the most location of the syntactic entity requiring the implicit 5193/// conversion 5194void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) { 5195 // Don't diagnose in unevaluated contexts. 5196 if (isUnevaluatedContext()) 5197 return; 5198 5199 // Don't diagnose for value- or type-dependent expressions. 5200 if (E->isTypeDependent() || E->isValueDependent()) 5201 return; 5202 5203 // Check for array bounds violations in cases where the check isn't triggered 5204 // elsewhere for other Expr types (like BinaryOperators), e.g. when an 5205 // ArraySubscriptExpr is on the RHS of a variable initialization. 5206 CheckArrayAccess(E); 5207 5208 // This is not the right CC for (e.g.) a variable initialization. 5209 AnalyzeImplicitConversions(*this, E, CC); 5210} 5211 5212/// Diagnose when expression is an integer constant expression and its evaluation 5213/// results in integer overflow 5214void Sema::CheckForIntOverflow (Expr *E) { 5215 if (isa<BinaryOperator>(E->IgnoreParens())) { 5216 llvm::SmallVector<PartialDiagnosticAt, 4> Diags; 5217 E->EvaluateForOverflow(Context, &Diags); 5218 } 5219} 5220 5221namespace { 5222/// \brief Visitor for expressions which looks for unsequenced operations on the 5223/// same object. 5224class SequenceChecker : public EvaluatedExprVisitor<SequenceChecker> { 5225 /// \brief A tree of sequenced regions within an expression. Two regions are 5226 /// unsequenced if one is an ancestor or a descendent of the other. When we 5227 /// finish processing an expression with sequencing, such as a comma 5228 /// expression, we fold its tree nodes into its parent, since they are 5229 /// unsequenced with respect to nodes we will visit later. 5230 class SequenceTree { 5231 struct Value { 5232 explicit Value(unsigned Parent) : Parent(Parent), Merged(false) {} 5233 unsigned Parent : 31; 5234 bool Merged : 1; 5235 }; 5236 llvm::SmallVector<Value, 8> Values; 5237 5238 public: 5239 /// \brief A region within an expression which may be sequenced with respect 5240 /// to some other region. 5241 class Seq { 5242 explicit Seq(unsigned N) : Index(N) {} 5243 unsigned Index; 5244 friend class SequenceTree; 5245 public: 5246 Seq() : Index(0) {} 5247 }; 5248 5249 SequenceTree() { Values.push_back(Value(0)); } 5250 Seq root() const { return Seq(0); } 5251 5252 /// \brief Create a new sequence of operations, which is an unsequenced 5253 /// subset of \p Parent. This sequence of operations is sequenced with 5254 /// respect to other children of \p Parent. 5255 Seq allocate(Seq Parent) { 5256 Values.push_back(Value(Parent.Index)); 5257 return Seq(Values.size() - 1); 5258 } 5259 5260 /// \brief Merge a sequence of operations into its parent. 5261 void merge(Seq S) { 5262 Values[S.Index].Merged = true; 5263 } 5264 5265 /// \brief Determine whether two operations are unsequenced. This operation 5266 /// is asymmetric: \p Cur should be the more recent sequence, and \p Old 5267 /// should have been merged into its parent as appropriate. 5268 bool isUnsequenced(Seq Cur, Seq Old) { 5269 unsigned C = representative(Cur.Index); 5270 unsigned Target = representative(Old.Index); 5271 while (C >= Target) { 5272 if (C == Target) 5273 return true; 5274 C = Values[C].Parent; 5275 } 5276 return false; 5277 } 5278 5279 private: 5280 /// \brief Pick a representative for a sequence. 5281 unsigned representative(unsigned K) { 5282 if (Values[K].Merged) 5283 // Perform path compression as we go. 5284 return Values[K].Parent = representative(Values[K].Parent); 5285 return K; 5286 } 5287 }; 5288 5289 /// An object for which we can track unsequenced uses. 5290 typedef NamedDecl *Object; 5291 5292 /// Different flavors of object usage which we track. We only track the 5293 /// least-sequenced usage of each kind. 5294 enum UsageKind { 5295 /// A read of an object. Multiple unsequenced reads are OK. 5296 UK_Use, 5297 /// A modification of an object which is sequenced before the value 5298 /// computation of the expression, such as ++n. 5299 UK_ModAsValue, 5300 /// A modification of an object which is not sequenced before the value 5301 /// computation of the expression, such as n++. 5302 UK_ModAsSideEffect, 5303 5304 UK_Count = UK_ModAsSideEffect + 1 5305 }; 5306 5307 struct Usage { 5308 Usage() : Use(0), Seq() {} 5309 Expr *Use; 5310 SequenceTree::Seq Seq; 5311 }; 5312 5313 struct UsageInfo { 5314 UsageInfo() : Diagnosed(false) {} 5315 Usage Uses[UK_Count]; 5316 /// Have we issued a diagnostic for this variable already? 5317 bool Diagnosed; 5318 }; 5319 typedef llvm::SmallDenseMap<Object, UsageInfo, 16> UsageInfoMap; 5320 5321 Sema &SemaRef; 5322 /// Sequenced regions within the expression. 5323 SequenceTree Tree; 5324 /// Declaration modifications and references which we have seen. 5325 UsageInfoMap UsageMap; 5326 /// The region we are currently within. 5327 SequenceTree::Seq Region; 5328 /// Filled in with declarations which were modified as a side-effect 5329 /// (that is, post-increment operations). 5330 llvm::SmallVectorImpl<std::pair<Object, Usage> > *ModAsSideEffect; 5331 /// Expressions to check later. We defer checking these to reduce 5332 /// stack usage. 5333 llvm::SmallVectorImpl<Expr*> &WorkList; 5334 5335 /// RAII object wrapping the visitation of a sequenced subexpression of an 5336 /// expression. At the end of this process, the side-effects of the evaluation 5337 /// become sequenced with respect to the value computation of the result, so 5338 /// we downgrade any UK_ModAsSideEffect within the evaluation to 5339 /// UK_ModAsValue. 5340 struct SequencedSubexpression { 5341 SequencedSubexpression(SequenceChecker &Self) 5342 : Self(Self), OldModAsSideEffect(Self.ModAsSideEffect) { 5343 Self.ModAsSideEffect = &ModAsSideEffect; 5344 } 5345 ~SequencedSubexpression() { 5346 for (unsigned I = 0, E = ModAsSideEffect.size(); I != E; ++I) { 5347 UsageInfo &U = Self.UsageMap[ModAsSideEffect[I].first]; 5348 U.Uses[UK_ModAsSideEffect] = ModAsSideEffect[I].second; 5349 Self.addUsage(U, ModAsSideEffect[I].first, 5350 ModAsSideEffect[I].second.Use, UK_ModAsValue); 5351 } 5352 Self.ModAsSideEffect = OldModAsSideEffect; 5353 } 5354 5355 SequenceChecker &Self; 5356 llvm::SmallVector<std::pair<Object, Usage>, 4> ModAsSideEffect; 5357 llvm::SmallVectorImpl<std::pair<Object, Usage> > *OldModAsSideEffect; 5358 }; 5359 5360 /// \brief Find the object which is produced by the specified expression, 5361 /// if any. 5362 Object getObject(Expr *E, bool Mod) const { 5363 E = E->IgnoreParenCasts(); 5364 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 5365 if (Mod && (UO->getOpcode() == UO_PreInc || UO->getOpcode() == UO_PreDec)) 5366 return getObject(UO->getSubExpr(), Mod); 5367 } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 5368 if (BO->getOpcode() == BO_Comma) 5369 return getObject(BO->getRHS(), Mod); 5370 if (Mod && BO->isAssignmentOp()) 5371 return getObject(BO->getLHS(), Mod); 5372 } else if (MemberExpr *ME = dyn_cast<MemberExpr>(E)) { 5373 // FIXME: Check for more interesting cases, like "x.n = ++x.n". 5374 if (isa<CXXThisExpr>(ME->getBase()->IgnoreParenCasts())) 5375 return ME->getMemberDecl(); 5376 } else if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 5377 // FIXME: If this is a reference, map through to its value. 5378 return DRE->getDecl(); 5379 return 0; 5380 } 5381 5382 /// \brief Note that an object was modified or used by an expression. 5383 void addUsage(UsageInfo &UI, Object O, Expr *Ref, UsageKind UK) { 5384 Usage &U = UI.Uses[UK]; 5385 if (!U.Use || !Tree.isUnsequenced(Region, U.Seq)) { 5386 if (UK == UK_ModAsSideEffect && ModAsSideEffect) 5387 ModAsSideEffect->push_back(std::make_pair(O, U)); 5388 U.Use = Ref; 5389 U.Seq = Region; 5390 } 5391 } 5392 /// \brief Check whether a modification or use conflicts with a prior usage. 5393 void checkUsage(Object O, UsageInfo &UI, Expr *Ref, UsageKind OtherKind, 5394 bool IsModMod) { 5395 if (UI.Diagnosed) 5396 return; 5397 5398 const Usage &U = UI.Uses[OtherKind]; 5399 if (!U.Use || !Tree.isUnsequenced(Region, U.Seq)) 5400 return; 5401 5402 Expr *Mod = U.Use; 5403 Expr *ModOrUse = Ref; 5404 if (OtherKind == UK_Use) 5405 std::swap(Mod, ModOrUse); 5406 5407 SemaRef.Diag(Mod->getExprLoc(), 5408 IsModMod ? diag::warn_unsequenced_mod_mod 5409 : diag::warn_unsequenced_mod_use) 5410 << O << SourceRange(ModOrUse->getExprLoc()); 5411 UI.Diagnosed = true; 5412 } 5413 5414 void notePreUse(Object O, Expr *Use) { 5415 UsageInfo &U = UsageMap[O]; 5416 // Uses conflict with other modifications. 5417 checkUsage(O, U, Use, UK_ModAsValue, false); 5418 } 5419 void notePostUse(Object O, Expr *Use) { 5420 UsageInfo &U = UsageMap[O]; 5421 checkUsage(O, U, Use, UK_ModAsSideEffect, false); 5422 addUsage(U, O, Use, UK_Use); 5423 } 5424 5425 void notePreMod(Object O, Expr *Mod) { 5426 UsageInfo &U = UsageMap[O]; 5427 // Modifications conflict with other modifications and with uses. 5428 checkUsage(O, U, Mod, UK_ModAsValue, true); 5429 checkUsage(O, U, Mod, UK_Use, false); 5430 } 5431 void notePostMod(Object O, Expr *Use, UsageKind UK) { 5432 UsageInfo &U = UsageMap[O]; 5433 checkUsage(O, U, Use, UK_ModAsSideEffect, true); 5434 addUsage(U, O, Use, UK); 5435 } 5436 5437public: 5438 SequenceChecker(Sema &S, Expr *E, 5439 llvm::SmallVectorImpl<Expr*> &WorkList) 5440 : EvaluatedExprVisitor<SequenceChecker>(S.Context), SemaRef(S), 5441 Region(Tree.root()), ModAsSideEffect(0), WorkList(WorkList) { 5442 Visit(E); 5443 } 5444 5445 void VisitStmt(Stmt *S) { 5446 // Skip all statements which aren't expressions for now. 5447 } 5448 5449 void VisitExpr(Expr *E) { 5450 // By default, just recurse to evaluated subexpressions. 5451 EvaluatedExprVisitor<SequenceChecker>::VisitStmt(E); 5452 } 5453 5454 void VisitCastExpr(CastExpr *E) { 5455 Object O = Object(); 5456 if (E->getCastKind() == CK_LValueToRValue) 5457 O = getObject(E->getSubExpr(), false); 5458 5459 if (O) 5460 notePreUse(O, E); 5461 VisitExpr(E); 5462 if (O) 5463 notePostUse(O, E); 5464 } 5465 5466 void VisitBinComma(BinaryOperator *BO) { 5467 // C++11 [expr.comma]p1: 5468 // Every value computation and side effect associated with the left 5469 // expression is sequenced before every value computation and side 5470 // effect associated with the right expression. 5471 SequenceTree::Seq LHS = Tree.allocate(Region); 5472 SequenceTree::Seq RHS = Tree.allocate(Region); 5473 SequenceTree::Seq OldRegion = Region; 5474 5475 { 5476 SequencedSubexpression SeqLHS(*this); 5477 Region = LHS; 5478 Visit(BO->getLHS()); 5479 } 5480 5481 Region = RHS; 5482 Visit(BO->getRHS()); 5483 5484 Region = OldRegion; 5485 5486 // Forget that LHS and RHS are sequenced. They are both unsequenced 5487 // with respect to other stuff. 5488 Tree.merge(LHS); 5489 Tree.merge(RHS); 5490 } 5491 5492 void VisitBinAssign(BinaryOperator *BO) { 5493 // The modification is sequenced after the value computation of the LHS 5494 // and RHS, so check it before inspecting the operands and update the 5495 // map afterwards. 5496 Object O = getObject(BO->getLHS(), true); 5497 if (!O) 5498 return VisitExpr(BO); 5499 5500 notePreMod(O, BO); 5501 5502 // C++11 [expr.ass]p7: 5503 // E1 op= E2 is equivalent to E1 = E1 op E2, except that E1 is evaluated 5504 // only once. 5505 // 5506 // Therefore, for a compound assignment operator, O is considered used 5507 // everywhere except within the evaluation of E1 itself. 5508 if (isa<CompoundAssignOperator>(BO)) 5509 notePreUse(O, BO); 5510 5511 Visit(BO->getLHS()); 5512 5513 if (isa<CompoundAssignOperator>(BO)) 5514 notePostUse(O, BO); 5515 5516 Visit(BO->getRHS()); 5517 5518 notePostMod(O, BO, UK_ModAsValue); 5519 } 5520 void VisitCompoundAssignOperator(CompoundAssignOperator *CAO) { 5521 VisitBinAssign(CAO); 5522 } 5523 5524 void VisitUnaryPreInc(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); } 5525 void VisitUnaryPreDec(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); } 5526 void VisitUnaryPreIncDec(UnaryOperator *UO) { 5527 Object O = getObject(UO->getSubExpr(), true); 5528 if (!O) 5529 return VisitExpr(UO); 5530 5531 notePreMod(O, UO); 5532 Visit(UO->getSubExpr()); 5533 notePostMod(O, UO, UK_ModAsValue); 5534 } 5535 5536 void VisitUnaryPostInc(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); } 5537 void VisitUnaryPostDec(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); } 5538 void VisitUnaryPostIncDec(UnaryOperator *UO) { 5539 Object O = getObject(UO->getSubExpr(), true); 5540 if (!O) 5541 return VisitExpr(UO); 5542 5543 notePreMod(O, UO); 5544 Visit(UO->getSubExpr()); 5545 notePostMod(O, UO, UK_ModAsSideEffect); 5546 } 5547 5548 /// Don't visit the RHS of '&&' or '||' if it might not be evaluated. 5549 void VisitBinLOr(BinaryOperator *BO) { 5550 // The side-effects of the LHS of an '&&' are sequenced before the 5551 // value computation of the RHS, and hence before the value computation 5552 // of the '&&' itself, unless the LHS evaluates to zero. We treat them 5553 // as if they were unconditionally sequenced. 5554 { 5555 SequencedSubexpression Sequenced(*this); 5556 Visit(BO->getLHS()); 5557 } 5558 5559 bool Result; 5560 if (!BO->getLHS()->isValueDependent() && 5561 BO->getLHS()->EvaluateAsBooleanCondition(Result, SemaRef.Context)) { 5562 if (!Result) 5563 Visit(BO->getRHS()); 5564 } else { 5565 // Check for unsequenced operations in the RHS, treating it as an 5566 // entirely separate evaluation. 5567 // 5568 // FIXME: If there are operations in the RHS which are unsequenced 5569 // with respect to operations outside the RHS, and those operations 5570 // are unconditionally evaluated, diagnose them. 5571 WorkList.push_back(BO->getRHS()); 5572 } 5573 } 5574 void VisitBinLAnd(BinaryOperator *BO) { 5575 { 5576 SequencedSubexpression Sequenced(*this); 5577 Visit(BO->getLHS()); 5578 } 5579 5580 bool Result; 5581 if (!BO->getLHS()->isValueDependent() && 5582 BO->getLHS()->EvaluateAsBooleanCondition(Result, SemaRef.Context)) { 5583 if (Result) 5584 Visit(BO->getRHS()); 5585 } else { 5586 WorkList.push_back(BO->getRHS()); 5587 } 5588 } 5589 5590 // Only visit the condition, unless we can be sure which subexpression will 5591 // be chosen. 5592 void VisitAbstractConditionalOperator(AbstractConditionalOperator *CO) { 5593 SequencedSubexpression Sequenced(*this); 5594 Visit(CO->getCond()); 5595 5596 bool Result; 5597 if (!CO->getCond()->isValueDependent() && 5598 CO->getCond()->EvaluateAsBooleanCondition(Result, SemaRef.Context)) 5599 Visit(Result ? CO->getTrueExpr() : CO->getFalseExpr()); 5600 else { 5601 WorkList.push_back(CO->getTrueExpr()); 5602 WorkList.push_back(CO->getFalseExpr()); 5603 } 5604 } 5605 5606 void VisitCXXConstructExpr(CXXConstructExpr *CCE) { 5607 if (!CCE->isListInitialization()) 5608 return VisitExpr(CCE); 5609 5610 // In C++11, list initializations are sequenced. 5611 llvm::SmallVector<SequenceTree::Seq, 32> Elts; 5612 SequenceTree::Seq Parent = Region; 5613 for (CXXConstructExpr::arg_iterator I = CCE->arg_begin(), 5614 E = CCE->arg_end(); 5615 I != E; ++I) { 5616 Region = Tree.allocate(Parent); 5617 Elts.push_back(Region); 5618 Visit(*I); 5619 } 5620 5621 // Forget that the initializers are sequenced. 5622 Region = Parent; 5623 for (unsigned I = 0; I < Elts.size(); ++I) 5624 Tree.merge(Elts[I]); 5625 } 5626 5627 void VisitInitListExpr(InitListExpr *ILE) { 5628 if (!SemaRef.getLangOpts().CPlusPlus11) 5629 return VisitExpr(ILE); 5630 5631 // In C++11, list initializations are sequenced. 5632 llvm::SmallVector<SequenceTree::Seq, 32> Elts; 5633 SequenceTree::Seq Parent = Region; 5634 for (unsigned I = 0; I < ILE->getNumInits(); ++I) { 5635 Expr *E = ILE->getInit(I); 5636 if (!E) continue; 5637 Region = Tree.allocate(Parent); 5638 Elts.push_back(Region); 5639 Visit(E); 5640 } 5641 5642 // Forget that the initializers are sequenced. 5643 Region = Parent; 5644 for (unsigned I = 0; I < Elts.size(); ++I) 5645 Tree.merge(Elts[I]); 5646 } 5647}; 5648} 5649 5650void Sema::CheckUnsequencedOperations(Expr *E) { 5651 llvm::SmallVector<Expr*, 8> WorkList; 5652 WorkList.push_back(E); 5653 while (!WorkList.empty()) { 5654 Expr *Item = WorkList.back(); 5655 WorkList.pop_back(); 5656 SequenceChecker(*this, Item, WorkList); 5657 } 5658} 5659 5660void Sema::CheckCompletedExpr(Expr *E, SourceLocation CheckLoc, 5661 bool IsConstexpr) { 5662 CheckImplicitConversions(E, CheckLoc); 5663 CheckUnsequencedOperations(E); 5664 if (!IsConstexpr && !E->isValueDependent()) 5665 CheckForIntOverflow(E); 5666} 5667 5668void Sema::CheckBitFieldInitialization(SourceLocation InitLoc, 5669 FieldDecl *BitField, 5670 Expr *Init) { 5671 (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc); 5672} 5673 5674/// CheckParmsForFunctionDef - Check that the parameters of the given 5675/// function are appropriate for the definition of a function. This 5676/// takes care of any checks that cannot be performed on the 5677/// declaration itself, e.g., that the types of each of the function 5678/// parameters are complete. 5679bool Sema::CheckParmsForFunctionDef(ParmVarDecl **P, ParmVarDecl **PEnd, 5680 bool CheckParameterNames) { 5681 bool HasInvalidParm = false; 5682 for (; P != PEnd; ++P) { 5683 ParmVarDecl *Param = *P; 5684 5685 // C99 6.7.5.3p4: the parameters in a parameter type list in a 5686 // function declarator that is part of a function definition of 5687 // that function shall not have incomplete type. 5688 // 5689 // This is also C++ [dcl.fct]p6. 5690 if (!Param->isInvalidDecl() && 5691 RequireCompleteType(Param->getLocation(), Param->getType(), 5692 diag::err_typecheck_decl_incomplete_type)) { 5693 Param->setInvalidDecl(); 5694 HasInvalidParm = true; 5695 } 5696 5697 // C99 6.9.1p5: If the declarator includes a parameter type list, the 5698 // declaration of each parameter shall include an identifier. 5699 if (CheckParameterNames && 5700 Param->getIdentifier() == 0 && 5701 !Param->isImplicit() && 5702 !getLangOpts().CPlusPlus) 5703 Diag(Param->getLocation(), diag::err_parameter_name_omitted); 5704 5705 // C99 6.7.5.3p12: 5706 // If the function declarator is not part of a definition of that 5707 // function, parameters may have incomplete type and may use the [*] 5708 // notation in their sequences of declarator specifiers to specify 5709 // variable length array types. 5710 QualType PType = Param->getOriginalType(); 5711 while (const ArrayType *AT = Context.getAsArrayType(PType)) { 5712 if (AT->getSizeModifier() == ArrayType::Star) { 5713 // FIXME: This diagnostic should point the '[*]' if source-location 5714 // information is added for it. 5715 Diag(Param->getLocation(), diag::err_array_star_in_function_definition); 5716 break; 5717 } 5718 PType= AT->getElementType(); 5719 } 5720 } 5721 5722 return HasInvalidParm; 5723} 5724 5725/// CheckCastAlign - Implements -Wcast-align, which warns when a 5726/// pointer cast increases the alignment requirements. 5727void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) { 5728 // This is actually a lot of work to potentially be doing on every 5729 // cast; don't do it if we're ignoring -Wcast_align (as is the default). 5730 if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align, 5731 TRange.getBegin()) 5732 == DiagnosticsEngine::Ignored) 5733 return; 5734 5735 // Ignore dependent types. 5736 if (T->isDependentType() || Op->getType()->isDependentType()) 5737 return; 5738 5739 // Require that the destination be a pointer type. 5740 const PointerType *DestPtr = T->getAs<PointerType>(); 5741 if (!DestPtr) return; 5742 5743 // If the destination has alignment 1, we're done. 5744 QualType DestPointee = DestPtr->getPointeeType(); 5745 if (DestPointee->isIncompleteType()) return; 5746 CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee); 5747 if (DestAlign.isOne()) return; 5748 5749 // Require that the source be a pointer type. 5750 const PointerType *SrcPtr = Op->getType()->getAs<PointerType>(); 5751 if (!SrcPtr) return; 5752 QualType SrcPointee = SrcPtr->getPointeeType(); 5753 5754 // Whitelist casts from cv void*. We already implicitly 5755 // whitelisted casts to cv void*, since they have alignment 1. 5756 // Also whitelist casts involving incomplete types, which implicitly 5757 // includes 'void'. 5758 if (SrcPointee->isIncompleteType()) return; 5759 5760 CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee); 5761 if (SrcAlign >= DestAlign) return; 5762 5763 Diag(TRange.getBegin(), diag::warn_cast_align) 5764 << Op->getType() << T 5765 << static_cast<unsigned>(SrcAlign.getQuantity()) 5766 << static_cast<unsigned>(DestAlign.getQuantity()) 5767 << TRange << Op->getSourceRange(); 5768} 5769 5770static const Type* getElementType(const Expr *BaseExpr) { 5771 const Type* EltType = BaseExpr->getType().getTypePtr(); 5772 if (EltType->isAnyPointerType()) 5773 return EltType->getPointeeType().getTypePtr(); 5774 else if (EltType->isArrayType()) 5775 return EltType->getBaseElementTypeUnsafe(); 5776 return EltType; 5777} 5778 5779/// \brief Check whether this array fits the idiom of a size-one tail padded 5780/// array member of a struct. 5781/// 5782/// We avoid emitting out-of-bounds access warnings for such arrays as they are 5783/// commonly used to emulate flexible arrays in C89 code. 5784static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size, 5785 const NamedDecl *ND) { 5786 if (Size != 1 || !ND) return false; 5787 5788 const FieldDecl *FD = dyn_cast<FieldDecl>(ND); 5789 if (!FD) return false; 5790 5791 // Don't consider sizes resulting from macro expansions or template argument 5792 // substitution to form C89 tail-padded arrays. 5793 5794 TypeSourceInfo *TInfo = FD->getTypeSourceInfo(); 5795 while (TInfo) { 5796 TypeLoc TL = TInfo->getTypeLoc(); 5797 // Look through typedefs. 5798 if (TypedefTypeLoc TTL = TL.getAs<TypedefTypeLoc>()) { 5799 const TypedefNameDecl *TDL = TTL.getTypedefNameDecl(); 5800 TInfo = TDL->getTypeSourceInfo(); 5801 continue; 5802 } 5803 if (ConstantArrayTypeLoc CTL = TL.getAs<ConstantArrayTypeLoc>()) { 5804 const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr()); 5805 if (!SizeExpr || SizeExpr->getExprLoc().isMacroID()) 5806 return false; 5807 } 5808 break; 5809 } 5810 5811 const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext()); 5812 if (!RD) return false; 5813 if (RD->isUnion()) return false; 5814 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) { 5815 if (!CRD->isStandardLayout()) return false; 5816 } 5817 5818 // See if this is the last field decl in the record. 5819 const Decl *D = FD; 5820 while ((D = D->getNextDeclInContext())) 5821 if (isa<FieldDecl>(D)) 5822 return false; 5823 return true; 5824} 5825 5826void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr, 5827 const ArraySubscriptExpr *ASE, 5828 bool AllowOnePastEnd, bool IndexNegated) { 5829 IndexExpr = IndexExpr->IgnoreParenImpCasts(); 5830 if (IndexExpr->isValueDependent()) 5831 return; 5832 5833 const Type *EffectiveType = getElementType(BaseExpr); 5834 BaseExpr = BaseExpr->IgnoreParenCasts(); 5835 const ConstantArrayType *ArrayTy = 5836 Context.getAsConstantArrayType(BaseExpr->getType()); 5837 if (!ArrayTy) 5838 return; 5839 5840 llvm::APSInt index; 5841 if (!IndexExpr->EvaluateAsInt(index, Context)) 5842 return; 5843 if (IndexNegated) 5844 index = -index; 5845 5846 const NamedDecl *ND = NULL; 5847 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 5848 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 5849 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 5850 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 5851 5852 if (index.isUnsigned() || !index.isNegative()) { 5853 llvm::APInt size = ArrayTy->getSize(); 5854 if (!size.isStrictlyPositive()) 5855 return; 5856 5857 const Type* BaseType = getElementType(BaseExpr); 5858 if (BaseType != EffectiveType) { 5859 // Make sure we're comparing apples to apples when comparing index to size 5860 uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType); 5861 uint64_t array_typesize = Context.getTypeSize(BaseType); 5862 // Handle ptrarith_typesize being zero, such as when casting to void* 5863 if (!ptrarith_typesize) ptrarith_typesize = 1; 5864 if (ptrarith_typesize != array_typesize) { 5865 // There's a cast to a different size type involved 5866 uint64_t ratio = array_typesize / ptrarith_typesize; 5867 // TODO: Be smarter about handling cases where array_typesize is not a 5868 // multiple of ptrarith_typesize 5869 if (ptrarith_typesize * ratio == array_typesize) 5870 size *= llvm::APInt(size.getBitWidth(), ratio); 5871 } 5872 } 5873 5874 if (size.getBitWidth() > index.getBitWidth()) 5875 index = index.zext(size.getBitWidth()); 5876 else if (size.getBitWidth() < index.getBitWidth()) 5877 size = size.zext(index.getBitWidth()); 5878 5879 // For array subscripting the index must be less than size, but for pointer 5880 // arithmetic also allow the index (offset) to be equal to size since 5881 // computing the next address after the end of the array is legal and 5882 // commonly done e.g. in C++ iterators and range-based for loops. 5883 if (AllowOnePastEnd ? index.ule(size) : index.ult(size)) 5884 return; 5885 5886 // Also don't warn for arrays of size 1 which are members of some 5887 // structure. These are often used to approximate flexible arrays in C89 5888 // code. 5889 if (IsTailPaddedMemberArray(*this, size, ND)) 5890 return; 5891 5892 // Suppress the warning if the subscript expression (as identified by the 5893 // ']' location) and the index expression are both from macro expansions 5894 // within a system header. 5895 if (ASE) { 5896 SourceLocation RBracketLoc = SourceMgr.getSpellingLoc( 5897 ASE->getRBracketLoc()); 5898 if (SourceMgr.isInSystemHeader(RBracketLoc)) { 5899 SourceLocation IndexLoc = SourceMgr.getSpellingLoc( 5900 IndexExpr->getLocStart()); 5901 if (SourceMgr.isFromSameFile(RBracketLoc, IndexLoc)) 5902 return; 5903 } 5904 } 5905 5906 unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds; 5907 if (ASE) 5908 DiagID = diag::warn_array_index_exceeds_bounds; 5909 5910 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 5911 PDiag(DiagID) << index.toString(10, true) 5912 << size.toString(10, true) 5913 << (unsigned)size.getLimitedValue(~0U) 5914 << IndexExpr->getSourceRange()); 5915 } else { 5916 unsigned DiagID = diag::warn_array_index_precedes_bounds; 5917 if (!ASE) { 5918 DiagID = diag::warn_ptr_arith_precedes_bounds; 5919 if (index.isNegative()) index = -index; 5920 } 5921 5922 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 5923 PDiag(DiagID) << index.toString(10, true) 5924 << IndexExpr->getSourceRange()); 5925 } 5926 5927 if (!ND) { 5928 // Try harder to find a NamedDecl to point at in the note. 5929 while (const ArraySubscriptExpr *ASE = 5930 dyn_cast<ArraySubscriptExpr>(BaseExpr)) 5931 BaseExpr = ASE->getBase()->IgnoreParenCasts(); 5932 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 5933 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 5934 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 5935 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 5936 } 5937 5938 if (ND) 5939 DiagRuntimeBehavior(ND->getLocStart(), BaseExpr, 5940 PDiag(diag::note_array_index_out_of_bounds) 5941 << ND->getDeclName()); 5942} 5943 5944void Sema::CheckArrayAccess(const Expr *expr) { 5945 int AllowOnePastEnd = 0; 5946 while (expr) { 5947 expr = expr->IgnoreParenImpCasts(); 5948 switch (expr->getStmtClass()) { 5949 case Stmt::ArraySubscriptExprClass: { 5950 const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr); 5951 CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE, 5952 AllowOnePastEnd > 0); 5953 return; 5954 } 5955 case Stmt::UnaryOperatorClass: { 5956 // Only unwrap the * and & unary operators 5957 const UnaryOperator *UO = cast<UnaryOperator>(expr); 5958 expr = UO->getSubExpr(); 5959 switch (UO->getOpcode()) { 5960 case UO_AddrOf: 5961 AllowOnePastEnd++; 5962 break; 5963 case UO_Deref: 5964 AllowOnePastEnd--; 5965 break; 5966 default: 5967 return; 5968 } 5969 break; 5970 } 5971 case Stmt::ConditionalOperatorClass: { 5972 const ConditionalOperator *cond = cast<ConditionalOperator>(expr); 5973 if (const Expr *lhs = cond->getLHS()) 5974 CheckArrayAccess(lhs); 5975 if (const Expr *rhs = cond->getRHS()) 5976 CheckArrayAccess(rhs); 5977 return; 5978 } 5979 default: 5980 return; 5981 } 5982 } 5983} 5984 5985//===--- CHECK: Objective-C retain cycles ----------------------------------// 5986 5987namespace { 5988 struct RetainCycleOwner { 5989 RetainCycleOwner() : Variable(0), Indirect(false) {} 5990 VarDecl *Variable; 5991 SourceRange Range; 5992 SourceLocation Loc; 5993 bool Indirect; 5994 5995 void setLocsFrom(Expr *e) { 5996 Loc = e->getExprLoc(); 5997 Range = e->getSourceRange(); 5998 } 5999 }; 6000} 6001 6002/// Consider whether capturing the given variable can possibly lead to 6003/// a retain cycle. 6004static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) { 6005 // In ARC, it's captured strongly iff the variable has __strong 6006 // lifetime. In MRR, it's captured strongly if the variable is 6007 // __block and has an appropriate type. 6008 if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 6009 return false; 6010 6011 owner.Variable = var; 6012 if (ref) 6013 owner.setLocsFrom(ref); 6014 return true; 6015} 6016 6017static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) { 6018 while (true) { 6019 e = e->IgnoreParens(); 6020 if (CastExpr *cast = dyn_cast<CastExpr>(e)) { 6021 switch (cast->getCastKind()) { 6022 case CK_BitCast: 6023 case CK_LValueBitCast: 6024 case CK_LValueToRValue: 6025 case CK_ARCReclaimReturnedObject: 6026 e = cast->getSubExpr(); 6027 continue; 6028 6029 default: 6030 return false; 6031 } 6032 } 6033 6034 if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) { 6035 ObjCIvarDecl *ivar = ref->getDecl(); 6036 if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 6037 return false; 6038 6039 // Try to find a retain cycle in the base. 6040 if (!findRetainCycleOwner(S, ref->getBase(), owner)) 6041 return false; 6042 6043 if (ref->isFreeIvar()) owner.setLocsFrom(ref); 6044 owner.Indirect = true; 6045 return true; 6046 } 6047 6048 if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) { 6049 VarDecl *var = dyn_cast<VarDecl>(ref->getDecl()); 6050 if (!var) return false; 6051 return considerVariable(var, ref, owner); 6052 } 6053 6054 if (MemberExpr *member = dyn_cast<MemberExpr>(e)) { 6055 if (member->isArrow()) return false; 6056 6057 // Don't count this as an indirect ownership. 6058 e = member->getBase(); 6059 continue; 6060 } 6061 6062 if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) { 6063 // Only pay attention to pseudo-objects on property references. 6064 ObjCPropertyRefExpr *pre 6065 = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm() 6066 ->IgnoreParens()); 6067 if (!pre) return false; 6068 if (pre->isImplicitProperty()) return false; 6069 ObjCPropertyDecl *property = pre->getExplicitProperty(); 6070 if (!property->isRetaining() && 6071 !(property->getPropertyIvarDecl() && 6072 property->getPropertyIvarDecl()->getType() 6073 .getObjCLifetime() == Qualifiers::OCL_Strong)) 6074 return false; 6075 6076 owner.Indirect = true; 6077 if (pre->isSuperReceiver()) { 6078 owner.Variable = S.getCurMethodDecl()->getSelfDecl(); 6079 if (!owner.Variable) 6080 return false; 6081 owner.Loc = pre->getLocation(); 6082 owner.Range = pre->getSourceRange(); 6083 return true; 6084 } 6085 e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase()) 6086 ->getSourceExpr()); 6087 continue; 6088 } 6089 6090 // Array ivars? 6091 6092 return false; 6093 } 6094} 6095 6096namespace { 6097 struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> { 6098 FindCaptureVisitor(ASTContext &Context, VarDecl *variable) 6099 : EvaluatedExprVisitor<FindCaptureVisitor>(Context), 6100 Variable(variable), Capturer(0) {} 6101 6102 VarDecl *Variable; 6103 Expr *Capturer; 6104 6105 void VisitDeclRefExpr(DeclRefExpr *ref) { 6106 if (ref->getDecl() == Variable && !Capturer) 6107 Capturer = ref; 6108 } 6109 6110 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) { 6111 if (Capturer) return; 6112 Visit(ref->getBase()); 6113 if (Capturer && ref->isFreeIvar()) 6114 Capturer = ref; 6115 } 6116 6117 void VisitBlockExpr(BlockExpr *block) { 6118 // Look inside nested blocks 6119 if (block->getBlockDecl()->capturesVariable(Variable)) 6120 Visit(block->getBlockDecl()->getBody()); 6121 } 6122 6123 void VisitOpaqueValueExpr(OpaqueValueExpr *OVE) { 6124 if (Capturer) return; 6125 if (OVE->getSourceExpr()) 6126 Visit(OVE->getSourceExpr()); 6127 } 6128 }; 6129} 6130 6131/// Check whether the given argument is a block which captures a 6132/// variable. 6133static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) { 6134 assert(owner.Variable && owner.Loc.isValid()); 6135 6136 e = e->IgnoreParenCasts(); 6137 6138 // Look through [^{...} copy] and Block_copy(^{...}). 6139 if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(e)) { 6140 Selector Cmd = ME->getSelector(); 6141 if (Cmd.isUnarySelector() && Cmd.getNameForSlot(0) == "copy") { 6142 e = ME->getInstanceReceiver(); 6143 if (!e) 6144 return 0; 6145 e = e->IgnoreParenCasts(); 6146 } 6147 } else if (CallExpr *CE = dyn_cast<CallExpr>(e)) { 6148 if (CE->getNumArgs() == 1) { 6149 FunctionDecl *Fn = dyn_cast_or_null<FunctionDecl>(CE->getCalleeDecl()); 6150 if (Fn) { 6151 const IdentifierInfo *FnI = Fn->getIdentifier(); 6152 if (FnI && FnI->isStr("_Block_copy")) { 6153 e = CE->getArg(0)->IgnoreParenCasts(); 6154 } 6155 } 6156 } 6157 } 6158 6159 BlockExpr *block = dyn_cast<BlockExpr>(e); 6160 if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable)) 6161 return 0; 6162 6163 FindCaptureVisitor visitor(S.Context, owner.Variable); 6164 visitor.Visit(block->getBlockDecl()->getBody()); 6165 return visitor.Capturer; 6166} 6167 6168static void diagnoseRetainCycle(Sema &S, Expr *capturer, 6169 RetainCycleOwner &owner) { 6170 assert(capturer); 6171 assert(owner.Variable && owner.Loc.isValid()); 6172 6173 S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle) 6174 << owner.Variable << capturer->getSourceRange(); 6175 S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner) 6176 << owner.Indirect << owner.Range; 6177} 6178 6179/// Check for a keyword selector that starts with the word 'add' or 6180/// 'set'. 6181static bool isSetterLikeSelector(Selector sel) { 6182 if (sel.isUnarySelector()) return false; 6183 6184 StringRef str = sel.getNameForSlot(0); 6185 while (!str.empty() && str.front() == '_') str = str.substr(1); 6186 if (str.startswith("set")) 6187 str = str.substr(3); 6188 else if (str.startswith("add")) { 6189 // Specially whitelist 'addOperationWithBlock:'. 6190 if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock")) 6191 return false; 6192 str = str.substr(3); 6193 } 6194 else 6195 return false; 6196 6197 if (str.empty()) return true; 6198 return !isLowercase(str.front()); 6199} 6200 6201/// Check a message send to see if it's likely to cause a retain cycle. 6202void Sema::checkRetainCycles(ObjCMessageExpr *msg) { 6203 // Only check instance methods whose selector looks like a setter. 6204 if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector())) 6205 return; 6206 6207 // Try to find a variable that the receiver is strongly owned by. 6208 RetainCycleOwner owner; 6209 if (msg->getReceiverKind() == ObjCMessageExpr::Instance) { 6210 if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner)) 6211 return; 6212 } else { 6213 assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance); 6214 owner.Variable = getCurMethodDecl()->getSelfDecl(); 6215 owner.Loc = msg->getSuperLoc(); 6216 owner.Range = msg->getSuperLoc(); 6217 } 6218 6219 // Check whether the receiver is captured by any of the arguments. 6220 for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i) 6221 if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner)) 6222 return diagnoseRetainCycle(*this, capturer, owner); 6223} 6224 6225/// Check a property assign to see if it's likely to cause a retain cycle. 6226void Sema::checkRetainCycles(Expr *receiver, Expr *argument) { 6227 RetainCycleOwner owner; 6228 if (!findRetainCycleOwner(*this, receiver, owner)) 6229 return; 6230 6231 if (Expr *capturer = findCapturingExpr(*this, argument, owner)) 6232 diagnoseRetainCycle(*this, capturer, owner); 6233} 6234 6235void Sema::checkRetainCycles(VarDecl *Var, Expr *Init) { 6236 RetainCycleOwner Owner; 6237 if (!considerVariable(Var, /*DeclRefExpr=*/0, Owner)) 6238 return; 6239 6240 // Because we don't have an expression for the variable, we have to set the 6241 // location explicitly here. 6242 Owner.Loc = Var->getLocation(); 6243 Owner.Range = Var->getSourceRange(); 6244 6245 if (Expr *Capturer = findCapturingExpr(*this, Init, Owner)) 6246 diagnoseRetainCycle(*this, Capturer, Owner); 6247} 6248 6249static bool checkUnsafeAssignLiteral(Sema &S, SourceLocation Loc, 6250 Expr *RHS, bool isProperty) { 6251 // Check if RHS is an Objective-C object literal, which also can get 6252 // immediately zapped in a weak reference. Note that we explicitly 6253 // allow ObjCStringLiterals, since those are designed to never really die. 6254 RHS = RHS->IgnoreParenImpCasts(); 6255 6256 // This enum needs to match with the 'select' in 6257 // warn_objc_arc_literal_assign (off-by-1). 6258 Sema::ObjCLiteralKind Kind = S.CheckLiteralKind(RHS); 6259 if (Kind == Sema::LK_String || Kind == Sema::LK_None) 6260 return false; 6261 6262 S.Diag(Loc, diag::warn_arc_literal_assign) 6263 << (unsigned) Kind 6264 << (isProperty ? 0 : 1) 6265 << RHS->getSourceRange(); 6266 6267 return true; 6268} 6269 6270static bool checkUnsafeAssignObject(Sema &S, SourceLocation Loc, 6271 Qualifiers::ObjCLifetime LT, 6272 Expr *RHS, bool isProperty) { 6273 // Strip off any implicit cast added to get to the one ARC-specific. 6274 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 6275 if (cast->getCastKind() == CK_ARCConsumeObject) { 6276 S.Diag(Loc, diag::warn_arc_retained_assign) 6277 << (LT == Qualifiers::OCL_ExplicitNone) 6278 << (isProperty ? 0 : 1) 6279 << RHS->getSourceRange(); 6280 return true; 6281 } 6282 RHS = cast->getSubExpr(); 6283 } 6284 6285 if (LT == Qualifiers::OCL_Weak && 6286 checkUnsafeAssignLiteral(S, Loc, RHS, isProperty)) 6287 return true; 6288 6289 return false; 6290} 6291 6292bool Sema::checkUnsafeAssigns(SourceLocation Loc, 6293 QualType LHS, Expr *RHS) { 6294 Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime(); 6295 6296 if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone) 6297 return false; 6298 6299 if (checkUnsafeAssignObject(*this, Loc, LT, RHS, false)) 6300 return true; 6301 6302 return false; 6303} 6304 6305void Sema::checkUnsafeExprAssigns(SourceLocation Loc, 6306 Expr *LHS, Expr *RHS) { 6307 QualType LHSType; 6308 // PropertyRef on LHS type need be directly obtained from 6309 // its declaration as it has a PsuedoType. 6310 ObjCPropertyRefExpr *PRE 6311 = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens()); 6312 if (PRE && !PRE->isImplicitProperty()) { 6313 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 6314 if (PD) 6315 LHSType = PD->getType(); 6316 } 6317 6318 if (LHSType.isNull()) 6319 LHSType = LHS->getType(); 6320 6321 Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime(); 6322 6323 if (LT == Qualifiers::OCL_Weak) { 6324 DiagnosticsEngine::Level Level = 6325 Diags.getDiagnosticLevel(diag::warn_arc_repeated_use_of_weak, Loc); 6326 if (Level != DiagnosticsEngine::Ignored) 6327 getCurFunction()->markSafeWeakUse(LHS); 6328 } 6329 6330 if (checkUnsafeAssigns(Loc, LHSType, RHS)) 6331 return; 6332 6333 // FIXME. Check for other life times. 6334 if (LT != Qualifiers::OCL_None) 6335 return; 6336 6337 if (PRE) { 6338 if (PRE->isImplicitProperty()) 6339 return; 6340 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 6341 if (!PD) 6342 return; 6343 6344 unsigned Attributes = PD->getPropertyAttributes(); 6345 if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) { 6346 // when 'assign' attribute was not explicitly specified 6347 // by user, ignore it and rely on property type itself 6348 // for lifetime info. 6349 unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten(); 6350 if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) && 6351 LHSType->isObjCRetainableType()) 6352 return; 6353 6354 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 6355 if (cast->getCastKind() == CK_ARCConsumeObject) { 6356 Diag(Loc, diag::warn_arc_retained_property_assign) 6357 << RHS->getSourceRange(); 6358 return; 6359 } 6360 RHS = cast->getSubExpr(); 6361 } 6362 } 6363 else if (Attributes & ObjCPropertyDecl::OBJC_PR_weak) { 6364 if (checkUnsafeAssignObject(*this, Loc, Qualifiers::OCL_Weak, RHS, true)) 6365 return; 6366 } 6367 } 6368} 6369 6370//===--- CHECK: Empty statement body (-Wempty-body) ---------------------===// 6371 6372namespace { 6373bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr, 6374 SourceLocation StmtLoc, 6375 const NullStmt *Body) { 6376 // Do not warn if the body is a macro that expands to nothing, e.g: 6377 // 6378 // #define CALL(x) 6379 // if (condition) 6380 // CALL(0); 6381 // 6382 if (Body->hasLeadingEmptyMacro()) 6383 return false; 6384 6385 // Get line numbers of statement and body. 6386 bool StmtLineInvalid; 6387 unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc, 6388 &StmtLineInvalid); 6389 if (StmtLineInvalid) 6390 return false; 6391 6392 bool BodyLineInvalid; 6393 unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(), 6394 &BodyLineInvalid); 6395 if (BodyLineInvalid) 6396 return false; 6397 6398 // Warn if null statement and body are on the same line. 6399 if (StmtLine != BodyLine) 6400 return false; 6401 6402 return true; 6403} 6404} // Unnamed namespace 6405 6406void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc, 6407 const Stmt *Body, 6408 unsigned DiagID) { 6409 // Since this is a syntactic check, don't emit diagnostic for template 6410 // instantiations, this just adds noise. 6411 if (CurrentInstantiationScope) 6412 return; 6413 6414 // The body should be a null statement. 6415 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 6416 if (!NBody) 6417 return; 6418 6419 // Do the usual checks. 6420 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 6421 return; 6422 6423 Diag(NBody->getSemiLoc(), DiagID); 6424 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 6425} 6426 6427void Sema::DiagnoseEmptyLoopBody(const Stmt *S, 6428 const Stmt *PossibleBody) { 6429 assert(!CurrentInstantiationScope); // Ensured by caller 6430 6431 SourceLocation StmtLoc; 6432 const Stmt *Body; 6433 unsigned DiagID; 6434 if (const ForStmt *FS = dyn_cast<ForStmt>(S)) { 6435 StmtLoc = FS->getRParenLoc(); 6436 Body = FS->getBody(); 6437 DiagID = diag::warn_empty_for_body; 6438 } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) { 6439 StmtLoc = WS->getCond()->getSourceRange().getEnd(); 6440 Body = WS->getBody(); 6441 DiagID = diag::warn_empty_while_body; 6442 } else 6443 return; // Neither `for' nor `while'. 6444 6445 // The body should be a null statement. 6446 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 6447 if (!NBody) 6448 return; 6449 6450 // Skip expensive checks if diagnostic is disabled. 6451 if (Diags.getDiagnosticLevel(DiagID, NBody->getSemiLoc()) == 6452 DiagnosticsEngine::Ignored) 6453 return; 6454 6455 // Do the usual checks. 6456 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 6457 return; 6458 6459 // `for(...);' and `while(...);' are popular idioms, so in order to keep 6460 // noise level low, emit diagnostics only if for/while is followed by a 6461 // CompoundStmt, e.g.: 6462 // for (int i = 0; i < n; i++); 6463 // { 6464 // a(i); 6465 // } 6466 // or if for/while is followed by a statement with more indentation 6467 // than for/while itself: 6468 // for (int i = 0; i < n; i++); 6469 // a(i); 6470 bool ProbableTypo = isa<CompoundStmt>(PossibleBody); 6471 if (!ProbableTypo) { 6472 bool BodyColInvalid; 6473 unsigned BodyCol = SourceMgr.getPresumedColumnNumber( 6474 PossibleBody->getLocStart(), 6475 &BodyColInvalid); 6476 if (BodyColInvalid) 6477 return; 6478 6479 bool StmtColInvalid; 6480 unsigned StmtCol = SourceMgr.getPresumedColumnNumber( 6481 S->getLocStart(), 6482 &StmtColInvalid); 6483 if (StmtColInvalid) 6484 return; 6485 6486 if (BodyCol > StmtCol) 6487 ProbableTypo = true; 6488 } 6489 6490 if (ProbableTypo) { 6491 Diag(NBody->getSemiLoc(), DiagID); 6492 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 6493 } 6494} 6495 6496//===--- Layout compatibility ----------------------------------------------// 6497 6498namespace { 6499 6500bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2); 6501 6502/// \brief Check if two enumeration types are layout-compatible. 6503bool isLayoutCompatible(ASTContext &C, EnumDecl *ED1, EnumDecl *ED2) { 6504 // C++11 [dcl.enum] p8: 6505 // Two enumeration types are layout-compatible if they have the same 6506 // underlying type. 6507 return ED1->isComplete() && ED2->isComplete() && 6508 C.hasSameType(ED1->getIntegerType(), ED2->getIntegerType()); 6509} 6510 6511/// \brief Check if two fields are layout-compatible. 6512bool isLayoutCompatible(ASTContext &C, FieldDecl *Field1, FieldDecl *Field2) { 6513 if (!isLayoutCompatible(C, Field1->getType(), Field2->getType())) 6514 return false; 6515 6516 if (Field1->isBitField() != Field2->isBitField()) 6517 return false; 6518 6519 if (Field1->isBitField()) { 6520 // Make sure that the bit-fields are the same length. 6521 unsigned Bits1 = Field1->getBitWidthValue(C); 6522 unsigned Bits2 = Field2->getBitWidthValue(C); 6523 6524 if (Bits1 != Bits2) 6525 return false; 6526 } 6527 6528 return true; 6529} 6530 6531/// \brief Check if two standard-layout structs are layout-compatible. 6532/// (C++11 [class.mem] p17) 6533bool isLayoutCompatibleStruct(ASTContext &C, 6534 RecordDecl *RD1, 6535 RecordDecl *RD2) { 6536 // If both records are C++ classes, check that base classes match. 6537 if (const CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(RD1)) { 6538 // If one of records is a CXXRecordDecl we are in C++ mode, 6539 // thus the other one is a CXXRecordDecl, too. 6540 const CXXRecordDecl *D2CXX = cast<CXXRecordDecl>(RD2); 6541 // Check number of base classes. 6542 if (D1CXX->getNumBases() != D2CXX->getNumBases()) 6543 return false; 6544 6545 // Check the base classes. 6546 for (CXXRecordDecl::base_class_const_iterator 6547 Base1 = D1CXX->bases_begin(), 6548 BaseEnd1 = D1CXX->bases_end(), 6549 Base2 = D2CXX->bases_begin(); 6550 Base1 != BaseEnd1; 6551 ++Base1, ++Base2) { 6552 if (!isLayoutCompatible(C, Base1->getType(), Base2->getType())) 6553 return false; 6554 } 6555 } else if (const CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(RD2)) { 6556 // If only RD2 is a C++ class, it should have zero base classes. 6557 if (D2CXX->getNumBases() > 0) 6558 return false; 6559 } 6560 6561 // Check the fields. 6562 RecordDecl::field_iterator Field2 = RD2->field_begin(), 6563 Field2End = RD2->field_end(), 6564 Field1 = RD1->field_begin(), 6565 Field1End = RD1->field_end(); 6566 for ( ; Field1 != Field1End && Field2 != Field2End; ++Field1, ++Field2) { 6567 if (!isLayoutCompatible(C, *Field1, *Field2)) 6568 return false; 6569 } 6570 if (Field1 != Field1End || Field2 != Field2End) 6571 return false; 6572 6573 return true; 6574} 6575 6576/// \brief Check if two standard-layout unions are layout-compatible. 6577/// (C++11 [class.mem] p18) 6578bool isLayoutCompatibleUnion(ASTContext &C, 6579 RecordDecl *RD1, 6580 RecordDecl *RD2) { 6581 llvm::SmallPtrSet<FieldDecl *, 8> UnmatchedFields; 6582 for (RecordDecl::field_iterator Field2 = RD2->field_begin(), 6583 Field2End = RD2->field_end(); 6584 Field2 != Field2End; ++Field2) { 6585 UnmatchedFields.insert(*Field2); 6586 } 6587 6588 for (RecordDecl::field_iterator Field1 = RD1->field_begin(), 6589 Field1End = RD1->field_end(); 6590 Field1 != Field1End; ++Field1) { 6591 llvm::SmallPtrSet<FieldDecl *, 8>::iterator 6592 I = UnmatchedFields.begin(), 6593 E = UnmatchedFields.end(); 6594 6595 for ( ; I != E; ++I) { 6596 if (isLayoutCompatible(C, *Field1, *I)) { 6597 bool Result = UnmatchedFields.erase(*I); 6598 (void) Result; 6599 assert(Result); 6600 break; 6601 } 6602 } 6603 if (I == E) 6604 return false; 6605 } 6606 6607 return UnmatchedFields.empty(); 6608} 6609 6610bool isLayoutCompatible(ASTContext &C, RecordDecl *RD1, RecordDecl *RD2) { 6611 if (RD1->isUnion() != RD2->isUnion()) 6612 return false; 6613 6614 if (RD1->isUnion()) 6615 return isLayoutCompatibleUnion(C, RD1, RD2); 6616 else 6617 return isLayoutCompatibleStruct(C, RD1, RD2); 6618} 6619 6620/// \brief Check if two types are layout-compatible in C++11 sense. 6621bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2) { 6622 if (T1.isNull() || T2.isNull()) 6623 return false; 6624 6625 // C++11 [basic.types] p11: 6626 // If two types T1 and T2 are the same type, then T1 and T2 are 6627 // layout-compatible types. 6628 if (C.hasSameType(T1, T2)) 6629 return true; 6630 6631 T1 = T1.getCanonicalType().getUnqualifiedType(); 6632 T2 = T2.getCanonicalType().getUnqualifiedType(); 6633 6634 const Type::TypeClass TC1 = T1->getTypeClass(); 6635 const Type::TypeClass TC2 = T2->getTypeClass(); 6636 6637 if (TC1 != TC2) 6638 return false; 6639 6640 if (TC1 == Type::Enum) { 6641 return isLayoutCompatible(C, 6642 cast<EnumType>(T1)->getDecl(), 6643 cast<EnumType>(T2)->getDecl()); 6644 } else if (TC1 == Type::Record) { 6645 if (!T1->isStandardLayoutType() || !T2->isStandardLayoutType()) 6646 return false; 6647 6648 return isLayoutCompatible(C, 6649 cast<RecordType>(T1)->getDecl(), 6650 cast<RecordType>(T2)->getDecl()); 6651 } 6652 6653 return false; 6654} 6655} 6656 6657//===--- CHECK: pointer_with_type_tag attribute: datatypes should match ----// 6658 6659namespace { 6660/// \brief Given a type tag expression find the type tag itself. 6661/// 6662/// \param TypeExpr Type tag expression, as it appears in user's code. 6663/// 6664/// \param VD Declaration of an identifier that appears in a type tag. 6665/// 6666/// \param MagicValue Type tag magic value. 6667bool FindTypeTagExpr(const Expr *TypeExpr, const ASTContext &Ctx, 6668 const ValueDecl **VD, uint64_t *MagicValue) { 6669 while(true) { 6670 if (!TypeExpr) 6671 return false; 6672 6673 TypeExpr = TypeExpr->IgnoreParenImpCasts()->IgnoreParenCasts(); 6674 6675 switch (TypeExpr->getStmtClass()) { 6676 case Stmt::UnaryOperatorClass: { 6677 const UnaryOperator *UO = cast<UnaryOperator>(TypeExpr); 6678 if (UO->getOpcode() == UO_AddrOf || UO->getOpcode() == UO_Deref) { 6679 TypeExpr = UO->getSubExpr(); 6680 continue; 6681 } 6682 return false; 6683 } 6684 6685 case Stmt::DeclRefExprClass: { 6686 const DeclRefExpr *DRE = cast<DeclRefExpr>(TypeExpr); 6687 *VD = DRE->getDecl(); 6688 return true; 6689 } 6690 6691 case Stmt::IntegerLiteralClass: { 6692 const IntegerLiteral *IL = cast<IntegerLiteral>(TypeExpr); 6693 llvm::APInt MagicValueAPInt = IL->getValue(); 6694 if (MagicValueAPInt.getActiveBits() <= 64) { 6695 *MagicValue = MagicValueAPInt.getZExtValue(); 6696 return true; 6697 } else 6698 return false; 6699 } 6700 6701 case Stmt::BinaryConditionalOperatorClass: 6702 case Stmt::ConditionalOperatorClass: { 6703 const AbstractConditionalOperator *ACO = 6704 cast<AbstractConditionalOperator>(TypeExpr); 6705 bool Result; 6706 if (ACO->getCond()->EvaluateAsBooleanCondition(Result, Ctx)) { 6707 if (Result) 6708 TypeExpr = ACO->getTrueExpr(); 6709 else 6710 TypeExpr = ACO->getFalseExpr(); 6711 continue; 6712 } 6713 return false; 6714 } 6715 6716 case Stmt::BinaryOperatorClass: { 6717 const BinaryOperator *BO = cast<BinaryOperator>(TypeExpr); 6718 if (BO->getOpcode() == BO_Comma) { 6719 TypeExpr = BO->getRHS(); 6720 continue; 6721 } 6722 return false; 6723 } 6724 6725 default: 6726 return false; 6727 } 6728 } 6729} 6730 6731/// \brief Retrieve the C type corresponding to type tag TypeExpr. 6732/// 6733/// \param TypeExpr Expression that specifies a type tag. 6734/// 6735/// \param MagicValues Registered magic values. 6736/// 6737/// \param FoundWrongKind Set to true if a type tag was found, but of a wrong 6738/// kind. 6739/// 6740/// \param TypeInfo Information about the corresponding C type. 6741/// 6742/// \returns true if the corresponding C type was found. 6743bool GetMatchingCType( 6744 const IdentifierInfo *ArgumentKind, 6745 const Expr *TypeExpr, const ASTContext &Ctx, 6746 const llvm::DenseMap<Sema::TypeTagMagicValue, 6747 Sema::TypeTagData> *MagicValues, 6748 bool &FoundWrongKind, 6749 Sema::TypeTagData &TypeInfo) { 6750 FoundWrongKind = false; 6751 6752 // Variable declaration that has type_tag_for_datatype attribute. 6753 const ValueDecl *VD = NULL; 6754 6755 uint64_t MagicValue; 6756 6757 if (!FindTypeTagExpr(TypeExpr, Ctx, &VD, &MagicValue)) 6758 return false; 6759 6760 if (VD) { 6761 for (specific_attr_iterator<TypeTagForDatatypeAttr> 6762 I = VD->specific_attr_begin<TypeTagForDatatypeAttr>(), 6763 E = VD->specific_attr_end<TypeTagForDatatypeAttr>(); 6764 I != E; ++I) { 6765 if (I->getArgumentKind() != ArgumentKind) { 6766 FoundWrongKind = true; 6767 return false; 6768 } 6769 TypeInfo.Type = I->getMatchingCType(); 6770 TypeInfo.LayoutCompatible = I->getLayoutCompatible(); 6771 TypeInfo.MustBeNull = I->getMustBeNull(); 6772 return true; 6773 } 6774 return false; 6775 } 6776 6777 if (!MagicValues) 6778 return false; 6779 6780 llvm::DenseMap<Sema::TypeTagMagicValue, 6781 Sema::TypeTagData>::const_iterator I = 6782 MagicValues->find(std::make_pair(ArgumentKind, MagicValue)); 6783 if (I == MagicValues->end()) 6784 return false; 6785 6786 TypeInfo = I->second; 6787 return true; 6788} 6789} // unnamed namespace 6790 6791void Sema::RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind, 6792 uint64_t MagicValue, QualType Type, 6793 bool LayoutCompatible, 6794 bool MustBeNull) { 6795 if (!TypeTagForDatatypeMagicValues) 6796 TypeTagForDatatypeMagicValues.reset( 6797 new llvm::DenseMap<TypeTagMagicValue, TypeTagData>); 6798 6799 TypeTagMagicValue Magic(ArgumentKind, MagicValue); 6800 (*TypeTagForDatatypeMagicValues)[Magic] = 6801 TypeTagData(Type, LayoutCompatible, MustBeNull); 6802} 6803 6804namespace { 6805bool IsSameCharType(QualType T1, QualType T2) { 6806 const BuiltinType *BT1 = T1->getAs<BuiltinType>(); 6807 if (!BT1) 6808 return false; 6809 6810 const BuiltinType *BT2 = T2->getAs<BuiltinType>(); 6811 if (!BT2) 6812 return false; 6813 6814 BuiltinType::Kind T1Kind = BT1->getKind(); 6815 BuiltinType::Kind T2Kind = BT2->getKind(); 6816 6817 return (T1Kind == BuiltinType::SChar && T2Kind == BuiltinType::Char_S) || 6818 (T1Kind == BuiltinType::UChar && T2Kind == BuiltinType::Char_U) || 6819 (T1Kind == BuiltinType::Char_U && T2Kind == BuiltinType::UChar) || 6820 (T1Kind == BuiltinType::Char_S && T2Kind == BuiltinType::SChar); 6821} 6822} // unnamed namespace 6823 6824void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr, 6825 const Expr * const *ExprArgs) { 6826 const IdentifierInfo *ArgumentKind = Attr->getArgumentKind(); 6827 bool IsPointerAttr = Attr->getIsPointer(); 6828 6829 const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()]; 6830 bool FoundWrongKind; 6831 TypeTagData TypeInfo; 6832 if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context, 6833 TypeTagForDatatypeMagicValues.get(), 6834 FoundWrongKind, TypeInfo)) { 6835 if (FoundWrongKind) 6836 Diag(TypeTagExpr->getExprLoc(), 6837 diag::warn_type_tag_for_datatype_wrong_kind) 6838 << TypeTagExpr->getSourceRange(); 6839 return; 6840 } 6841 6842 const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()]; 6843 if (IsPointerAttr) { 6844 // Skip implicit cast of pointer to `void *' (as a function argument). 6845 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr)) 6846 if (ICE->getType()->isVoidPointerType() && 6847 ICE->getCastKind() == CK_BitCast) 6848 ArgumentExpr = ICE->getSubExpr(); 6849 } 6850 QualType ArgumentType = ArgumentExpr->getType(); 6851 6852 // Passing a `void*' pointer shouldn't trigger a warning. 6853 if (IsPointerAttr && ArgumentType->isVoidPointerType()) 6854 return; 6855 6856 if (TypeInfo.MustBeNull) { 6857 // Type tag with matching void type requires a null pointer. 6858 if (!ArgumentExpr->isNullPointerConstant(Context, 6859 Expr::NPC_ValueDependentIsNotNull)) { 6860 Diag(ArgumentExpr->getExprLoc(), 6861 diag::warn_type_safety_null_pointer_required) 6862 << ArgumentKind->getName() 6863 << ArgumentExpr->getSourceRange() 6864 << TypeTagExpr->getSourceRange(); 6865 } 6866 return; 6867 } 6868 6869 QualType RequiredType = TypeInfo.Type; 6870 if (IsPointerAttr) 6871 RequiredType = Context.getPointerType(RequiredType); 6872 6873 bool mismatch = false; 6874 if (!TypeInfo.LayoutCompatible) { 6875 mismatch = !Context.hasSameType(ArgumentType, RequiredType); 6876 6877 // C++11 [basic.fundamental] p1: 6878 // Plain char, signed char, and unsigned char are three distinct types. 6879 // 6880 // But we treat plain `char' as equivalent to `signed char' or `unsigned 6881 // char' depending on the current char signedness mode. 6882 if (mismatch) 6883 if ((IsPointerAttr && IsSameCharType(ArgumentType->getPointeeType(), 6884 RequiredType->getPointeeType())) || 6885 (!IsPointerAttr && IsSameCharType(ArgumentType, RequiredType))) 6886 mismatch = false; 6887 } else 6888 if (IsPointerAttr) 6889 mismatch = !isLayoutCompatible(Context, 6890 ArgumentType->getPointeeType(), 6891 RequiredType->getPointeeType()); 6892 else 6893 mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType); 6894 6895 if (mismatch) 6896 Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch) 6897 << ArgumentType << ArgumentKind->getName() 6898 << TypeInfo.LayoutCompatible << RequiredType 6899 << ArgumentExpr->getSourceRange() 6900 << TypeTagExpr->getSourceRange(); 6901} 6902