SemaChecking.cpp revision 670941c28c0683ecc251dafdf093a71629625dc9
1//===--- SemaChecking.cpp - Extra Semantic Checking -----------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements extra semantic analysis beyond what is enforced 11// by the C type system. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/Sema/Initialization.h" 16#include "clang/Sema/Sema.h" 17#include "clang/Sema/SemaInternal.h" 18#include "clang/Sema/Initialization.h" 19#include "clang/Sema/Lookup.h" 20#include "clang/Sema/ScopeInfo.h" 21#include "clang/Analysis/Analyses/FormatString.h" 22#include "clang/AST/ASTContext.h" 23#include "clang/AST/CharUnits.h" 24#include "clang/AST/DeclCXX.h" 25#include "clang/AST/DeclObjC.h" 26#include "clang/AST/Expr.h" 27#include "clang/AST/ExprCXX.h" 28#include "clang/AST/ExprObjC.h" 29#include "clang/AST/EvaluatedExprVisitor.h" 30#include "clang/AST/DeclObjC.h" 31#include "clang/AST/StmtCXX.h" 32#include "clang/AST/StmtObjC.h" 33#include "clang/Lex/Preprocessor.h" 34#include "llvm/ADT/BitVector.h" 35#include "llvm/ADT/SmallString.h" 36#include "llvm/ADT/STLExtras.h" 37#include "llvm/Support/raw_ostream.h" 38#include "clang/Basic/TargetBuiltins.h" 39#include "clang/Basic/TargetInfo.h" 40#include "clang/Basic/ConvertUTF.h" 41#include <limits> 42using namespace clang; 43using namespace sema; 44 45SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL, 46 unsigned ByteNo) const { 47 return SL->getLocationOfByte(ByteNo, PP.getSourceManager(), 48 PP.getLangOpts(), PP.getTargetInfo()); 49} 50 51/// Checks that a call expression's argument count is the desired number. 52/// This is useful when doing custom type-checking. Returns true on error. 53static bool checkArgCount(Sema &S, CallExpr *call, unsigned desiredArgCount) { 54 unsigned argCount = call->getNumArgs(); 55 if (argCount == desiredArgCount) return false; 56 57 if (argCount < desiredArgCount) 58 return S.Diag(call->getLocEnd(), diag::err_typecheck_call_too_few_args) 59 << 0 /*function call*/ << desiredArgCount << argCount 60 << call->getSourceRange(); 61 62 // Highlight all the excess arguments. 63 SourceRange range(call->getArg(desiredArgCount)->getLocStart(), 64 call->getArg(argCount - 1)->getLocEnd()); 65 66 return S.Diag(range.getBegin(), diag::err_typecheck_call_too_many_args) 67 << 0 /*function call*/ << desiredArgCount << argCount 68 << call->getArg(1)->getSourceRange(); 69} 70 71/// Check that the first argument to __builtin_annotation is an integer 72/// and the second argument is a non-wide string literal. 73static bool SemaBuiltinAnnotation(Sema &S, CallExpr *TheCall) { 74 if (checkArgCount(S, TheCall, 2)) 75 return true; 76 77 // First argument should be an integer. 78 Expr *ValArg = TheCall->getArg(0); 79 QualType Ty = ValArg->getType(); 80 if (!Ty->isIntegerType()) { 81 S.Diag(ValArg->getLocStart(), diag::err_builtin_annotation_first_arg) 82 << ValArg->getSourceRange(); 83 return true; 84 } 85 86 // Second argument should be a constant string. 87 Expr *StrArg = TheCall->getArg(1)->IgnoreParenCasts(); 88 StringLiteral *Literal = dyn_cast<StringLiteral>(StrArg); 89 if (!Literal || !Literal->isAscii()) { 90 S.Diag(StrArg->getLocStart(), diag::err_builtin_annotation_second_arg) 91 << StrArg->getSourceRange(); 92 return true; 93 } 94 95 TheCall->setType(Ty); 96 return false; 97} 98 99ExprResult 100Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 101 ExprResult TheCallResult(Owned(TheCall)); 102 103 // Find out if any arguments are required to be integer constant expressions. 104 unsigned ICEArguments = 0; 105 ASTContext::GetBuiltinTypeError Error; 106 Context.GetBuiltinType(BuiltinID, Error, &ICEArguments); 107 if (Error != ASTContext::GE_None) 108 ICEArguments = 0; // Don't diagnose previously diagnosed errors. 109 110 // If any arguments are required to be ICE's, check and diagnose. 111 for (unsigned ArgNo = 0; ICEArguments != 0; ++ArgNo) { 112 // Skip arguments not required to be ICE's. 113 if ((ICEArguments & (1 << ArgNo)) == 0) continue; 114 115 llvm::APSInt Result; 116 if (SemaBuiltinConstantArg(TheCall, ArgNo, Result)) 117 return true; 118 ICEArguments &= ~(1 << ArgNo); 119 } 120 121 switch (BuiltinID) { 122 case Builtin::BI__builtin___CFStringMakeConstantString: 123 assert(TheCall->getNumArgs() == 1 && 124 "Wrong # arguments to builtin CFStringMakeConstantString"); 125 if (CheckObjCString(TheCall->getArg(0))) 126 return ExprError(); 127 break; 128 case Builtin::BI__builtin_stdarg_start: 129 case Builtin::BI__builtin_va_start: 130 if (SemaBuiltinVAStart(TheCall)) 131 return ExprError(); 132 break; 133 case Builtin::BI__builtin_isgreater: 134 case Builtin::BI__builtin_isgreaterequal: 135 case Builtin::BI__builtin_isless: 136 case Builtin::BI__builtin_islessequal: 137 case Builtin::BI__builtin_islessgreater: 138 case Builtin::BI__builtin_isunordered: 139 if (SemaBuiltinUnorderedCompare(TheCall)) 140 return ExprError(); 141 break; 142 case Builtin::BI__builtin_fpclassify: 143 if (SemaBuiltinFPClassification(TheCall, 6)) 144 return ExprError(); 145 break; 146 case Builtin::BI__builtin_isfinite: 147 case Builtin::BI__builtin_isinf: 148 case Builtin::BI__builtin_isinf_sign: 149 case Builtin::BI__builtin_isnan: 150 case Builtin::BI__builtin_isnormal: 151 if (SemaBuiltinFPClassification(TheCall, 1)) 152 return ExprError(); 153 break; 154 case Builtin::BI__builtin_shufflevector: 155 return SemaBuiltinShuffleVector(TheCall); 156 // TheCall will be freed by the smart pointer here, but that's fine, since 157 // SemaBuiltinShuffleVector guts it, but then doesn't release it. 158 case Builtin::BI__builtin_prefetch: 159 if (SemaBuiltinPrefetch(TheCall)) 160 return ExprError(); 161 break; 162 case Builtin::BI__builtin_object_size: 163 if (SemaBuiltinObjectSize(TheCall)) 164 return ExprError(); 165 break; 166 case Builtin::BI__builtin_longjmp: 167 if (SemaBuiltinLongjmp(TheCall)) 168 return ExprError(); 169 break; 170 171 case Builtin::BI__builtin_classify_type: 172 if (checkArgCount(*this, TheCall, 1)) return true; 173 TheCall->setType(Context.IntTy); 174 break; 175 case Builtin::BI__builtin_constant_p: 176 if (checkArgCount(*this, TheCall, 1)) return true; 177 TheCall->setType(Context.IntTy); 178 break; 179 case Builtin::BI__sync_fetch_and_add: 180 case Builtin::BI__sync_fetch_and_add_1: 181 case Builtin::BI__sync_fetch_and_add_2: 182 case Builtin::BI__sync_fetch_and_add_4: 183 case Builtin::BI__sync_fetch_and_add_8: 184 case Builtin::BI__sync_fetch_and_add_16: 185 case Builtin::BI__sync_fetch_and_sub: 186 case Builtin::BI__sync_fetch_and_sub_1: 187 case Builtin::BI__sync_fetch_and_sub_2: 188 case Builtin::BI__sync_fetch_and_sub_4: 189 case Builtin::BI__sync_fetch_and_sub_8: 190 case Builtin::BI__sync_fetch_and_sub_16: 191 case Builtin::BI__sync_fetch_and_or: 192 case Builtin::BI__sync_fetch_and_or_1: 193 case Builtin::BI__sync_fetch_and_or_2: 194 case Builtin::BI__sync_fetch_and_or_4: 195 case Builtin::BI__sync_fetch_and_or_8: 196 case Builtin::BI__sync_fetch_and_or_16: 197 case Builtin::BI__sync_fetch_and_and: 198 case Builtin::BI__sync_fetch_and_and_1: 199 case Builtin::BI__sync_fetch_and_and_2: 200 case Builtin::BI__sync_fetch_and_and_4: 201 case Builtin::BI__sync_fetch_and_and_8: 202 case Builtin::BI__sync_fetch_and_and_16: 203 case Builtin::BI__sync_fetch_and_xor: 204 case Builtin::BI__sync_fetch_and_xor_1: 205 case Builtin::BI__sync_fetch_and_xor_2: 206 case Builtin::BI__sync_fetch_and_xor_4: 207 case Builtin::BI__sync_fetch_and_xor_8: 208 case Builtin::BI__sync_fetch_and_xor_16: 209 case Builtin::BI__sync_add_and_fetch: 210 case Builtin::BI__sync_add_and_fetch_1: 211 case Builtin::BI__sync_add_and_fetch_2: 212 case Builtin::BI__sync_add_and_fetch_4: 213 case Builtin::BI__sync_add_and_fetch_8: 214 case Builtin::BI__sync_add_and_fetch_16: 215 case Builtin::BI__sync_sub_and_fetch: 216 case Builtin::BI__sync_sub_and_fetch_1: 217 case Builtin::BI__sync_sub_and_fetch_2: 218 case Builtin::BI__sync_sub_and_fetch_4: 219 case Builtin::BI__sync_sub_and_fetch_8: 220 case Builtin::BI__sync_sub_and_fetch_16: 221 case Builtin::BI__sync_and_and_fetch: 222 case Builtin::BI__sync_and_and_fetch_1: 223 case Builtin::BI__sync_and_and_fetch_2: 224 case Builtin::BI__sync_and_and_fetch_4: 225 case Builtin::BI__sync_and_and_fetch_8: 226 case Builtin::BI__sync_and_and_fetch_16: 227 case Builtin::BI__sync_or_and_fetch: 228 case Builtin::BI__sync_or_and_fetch_1: 229 case Builtin::BI__sync_or_and_fetch_2: 230 case Builtin::BI__sync_or_and_fetch_4: 231 case Builtin::BI__sync_or_and_fetch_8: 232 case Builtin::BI__sync_or_and_fetch_16: 233 case Builtin::BI__sync_xor_and_fetch: 234 case Builtin::BI__sync_xor_and_fetch_1: 235 case Builtin::BI__sync_xor_and_fetch_2: 236 case Builtin::BI__sync_xor_and_fetch_4: 237 case Builtin::BI__sync_xor_and_fetch_8: 238 case Builtin::BI__sync_xor_and_fetch_16: 239 case Builtin::BI__sync_val_compare_and_swap: 240 case Builtin::BI__sync_val_compare_and_swap_1: 241 case Builtin::BI__sync_val_compare_and_swap_2: 242 case Builtin::BI__sync_val_compare_and_swap_4: 243 case Builtin::BI__sync_val_compare_and_swap_8: 244 case Builtin::BI__sync_val_compare_and_swap_16: 245 case Builtin::BI__sync_bool_compare_and_swap: 246 case Builtin::BI__sync_bool_compare_and_swap_1: 247 case Builtin::BI__sync_bool_compare_and_swap_2: 248 case Builtin::BI__sync_bool_compare_and_swap_4: 249 case Builtin::BI__sync_bool_compare_and_swap_8: 250 case Builtin::BI__sync_bool_compare_and_swap_16: 251 case Builtin::BI__sync_lock_test_and_set: 252 case Builtin::BI__sync_lock_test_and_set_1: 253 case Builtin::BI__sync_lock_test_and_set_2: 254 case Builtin::BI__sync_lock_test_and_set_4: 255 case Builtin::BI__sync_lock_test_and_set_8: 256 case Builtin::BI__sync_lock_test_and_set_16: 257 case Builtin::BI__sync_lock_release: 258 case Builtin::BI__sync_lock_release_1: 259 case Builtin::BI__sync_lock_release_2: 260 case Builtin::BI__sync_lock_release_4: 261 case Builtin::BI__sync_lock_release_8: 262 case Builtin::BI__sync_lock_release_16: 263 case Builtin::BI__sync_swap: 264 case Builtin::BI__sync_swap_1: 265 case Builtin::BI__sync_swap_2: 266 case Builtin::BI__sync_swap_4: 267 case Builtin::BI__sync_swap_8: 268 case Builtin::BI__sync_swap_16: 269 return SemaBuiltinAtomicOverloaded(TheCallResult); 270#define BUILTIN(ID, TYPE, ATTRS) 271#define ATOMIC_BUILTIN(ID, TYPE, ATTRS) \ 272 case Builtin::BI##ID: \ 273 return SemaAtomicOpsOverloaded(TheCallResult, AtomicExpr::AO##ID); 274#include "clang/Basic/Builtins.def" 275 case Builtin::BI__builtin_annotation: 276 if (SemaBuiltinAnnotation(*this, TheCall)) 277 return ExprError(); 278 break; 279 } 280 281 // Since the target specific builtins for each arch overlap, only check those 282 // of the arch we are compiling for. 283 if (BuiltinID >= Builtin::FirstTSBuiltin) { 284 switch (Context.getTargetInfo().getTriple().getArch()) { 285 case llvm::Triple::arm: 286 case llvm::Triple::thumb: 287 if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall)) 288 return ExprError(); 289 break; 290 case llvm::Triple::mips: 291 case llvm::Triple::mipsel: 292 case llvm::Triple::mips64: 293 case llvm::Triple::mips64el: 294 if (CheckMipsBuiltinFunctionCall(BuiltinID, TheCall)) 295 return ExprError(); 296 break; 297 default: 298 break; 299 } 300 } 301 302 return TheCallResult; 303} 304 305// Get the valid immediate range for the specified NEON type code. 306static unsigned RFT(unsigned t, bool shift = false) { 307 NeonTypeFlags Type(t); 308 int IsQuad = Type.isQuad(); 309 switch (Type.getEltType()) { 310 case NeonTypeFlags::Int8: 311 case NeonTypeFlags::Poly8: 312 return shift ? 7 : (8 << IsQuad) - 1; 313 case NeonTypeFlags::Int16: 314 case NeonTypeFlags::Poly16: 315 return shift ? 15 : (4 << IsQuad) - 1; 316 case NeonTypeFlags::Int32: 317 return shift ? 31 : (2 << IsQuad) - 1; 318 case NeonTypeFlags::Int64: 319 return shift ? 63 : (1 << IsQuad) - 1; 320 case NeonTypeFlags::Float16: 321 assert(!shift && "cannot shift float types!"); 322 return (4 << IsQuad) - 1; 323 case NeonTypeFlags::Float32: 324 assert(!shift && "cannot shift float types!"); 325 return (2 << IsQuad) - 1; 326 } 327 llvm_unreachable("Invalid NeonTypeFlag!"); 328} 329 330/// getNeonEltType - Return the QualType corresponding to the elements of 331/// the vector type specified by the NeonTypeFlags. This is used to check 332/// the pointer arguments for Neon load/store intrinsics. 333static QualType getNeonEltType(NeonTypeFlags Flags, ASTContext &Context) { 334 switch (Flags.getEltType()) { 335 case NeonTypeFlags::Int8: 336 return Flags.isUnsigned() ? Context.UnsignedCharTy : Context.SignedCharTy; 337 case NeonTypeFlags::Int16: 338 return Flags.isUnsigned() ? Context.UnsignedShortTy : Context.ShortTy; 339 case NeonTypeFlags::Int32: 340 return Flags.isUnsigned() ? Context.UnsignedIntTy : Context.IntTy; 341 case NeonTypeFlags::Int64: 342 return Flags.isUnsigned() ? Context.UnsignedLongLongTy : Context.LongLongTy; 343 case NeonTypeFlags::Poly8: 344 return Context.SignedCharTy; 345 case NeonTypeFlags::Poly16: 346 return Context.ShortTy; 347 case NeonTypeFlags::Float16: 348 return Context.UnsignedShortTy; 349 case NeonTypeFlags::Float32: 350 return Context.FloatTy; 351 } 352 llvm_unreachable("Invalid NeonTypeFlag!"); 353} 354 355bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 356 llvm::APSInt Result; 357 358 uint64_t mask = 0; 359 unsigned TV = 0; 360 int PtrArgNum = -1; 361 bool HasConstPtr = false; 362 switch (BuiltinID) { 363#define GET_NEON_OVERLOAD_CHECK 364#include "clang/Basic/arm_neon.inc" 365#undef GET_NEON_OVERLOAD_CHECK 366 } 367 368 // For NEON intrinsics which are overloaded on vector element type, validate 369 // the immediate which specifies which variant to emit. 370 unsigned ImmArg = TheCall->getNumArgs()-1; 371 if (mask) { 372 if (SemaBuiltinConstantArg(TheCall, ImmArg, Result)) 373 return true; 374 375 TV = Result.getLimitedValue(64); 376 if ((TV > 63) || (mask & (1ULL << TV)) == 0) 377 return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code) 378 << TheCall->getArg(ImmArg)->getSourceRange(); 379 } 380 381 if (PtrArgNum >= 0) { 382 // Check that pointer arguments have the specified type. 383 Expr *Arg = TheCall->getArg(PtrArgNum); 384 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) 385 Arg = ICE->getSubExpr(); 386 ExprResult RHS = DefaultFunctionArrayLvalueConversion(Arg); 387 QualType RHSTy = RHS.get()->getType(); 388 QualType EltTy = getNeonEltType(NeonTypeFlags(TV), Context); 389 if (HasConstPtr) 390 EltTy = EltTy.withConst(); 391 QualType LHSTy = Context.getPointerType(EltTy); 392 AssignConvertType ConvTy; 393 ConvTy = CheckSingleAssignmentConstraints(LHSTy, RHS); 394 if (RHS.isInvalid()) 395 return true; 396 if (DiagnoseAssignmentResult(ConvTy, Arg->getLocStart(), LHSTy, RHSTy, 397 RHS.get(), AA_Assigning)) 398 return true; 399 } 400 401 // For NEON intrinsics which take an immediate value as part of the 402 // instruction, range check them here. 403 unsigned i = 0, l = 0, u = 0; 404 switch (BuiltinID) { 405 default: return false; 406 case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break; 407 case ARM::BI__builtin_arm_usat: i = 1; u = 31; break; 408 case ARM::BI__builtin_arm_vcvtr_f: 409 case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break; 410#define GET_NEON_IMMEDIATE_CHECK 411#include "clang/Basic/arm_neon.inc" 412#undef GET_NEON_IMMEDIATE_CHECK 413 }; 414 415 // We can't check the value of a dependent argument. 416 if (TheCall->getArg(i)->isTypeDependent() || 417 TheCall->getArg(i)->isValueDependent()) 418 return false; 419 420 // Check that the immediate argument is actually a constant. 421 if (SemaBuiltinConstantArg(TheCall, i, Result)) 422 return true; 423 424 // Range check against the upper/lower values for this isntruction. 425 unsigned Val = Result.getZExtValue(); 426 if (Val < l || Val > (u + l)) 427 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 428 << l << u+l << TheCall->getArg(i)->getSourceRange(); 429 430 // FIXME: VFP Intrinsics should error if VFP not present. 431 return false; 432} 433 434bool Sema::CheckMipsBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 435 unsigned i = 0, l = 0, u = 0; 436 switch (BuiltinID) { 437 default: return false; 438 case Mips::BI__builtin_mips_wrdsp: i = 1; l = 0; u = 63; break; 439 case Mips::BI__builtin_mips_rddsp: i = 0; l = 0; u = 63; break; 440 case Mips::BI__builtin_mips_append: i = 2; l = 0; u = 31; break; 441 case Mips::BI__builtin_mips_balign: i = 2; l = 0; u = 3; break; 442 case Mips::BI__builtin_mips_precr_sra_ph_w: i = 2; l = 0; u = 31; break; 443 case Mips::BI__builtin_mips_precr_sra_r_ph_w: i = 2; l = 0; u = 31; break; 444 case Mips::BI__builtin_mips_prepend: i = 2; l = 0; u = 31; break; 445 }; 446 447 // We can't check the value of a dependent argument. 448 if (TheCall->getArg(i)->isTypeDependent() || 449 TheCall->getArg(i)->isValueDependent()) 450 return false; 451 452 // Check that the immediate argument is actually a constant. 453 llvm::APSInt Result; 454 if (SemaBuiltinConstantArg(TheCall, i, Result)) 455 return true; 456 457 // Range check against the upper/lower values for this instruction. 458 unsigned Val = Result.getZExtValue(); 459 if (Val < l || Val > u) 460 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 461 << l << u << TheCall->getArg(i)->getSourceRange(); 462 463 return false; 464} 465 466/// Given a FunctionDecl's FormatAttr, attempts to populate the FomatStringInfo 467/// parameter with the FormatAttr's correct format_idx and firstDataArg. 468/// Returns true when the format fits the function and the FormatStringInfo has 469/// been populated. 470bool Sema::getFormatStringInfo(const FormatAttr *Format, bool IsCXXMember, 471 FormatStringInfo *FSI) { 472 FSI->HasVAListArg = Format->getFirstArg() == 0; 473 FSI->FormatIdx = Format->getFormatIdx() - 1; 474 FSI->FirstDataArg = FSI->HasVAListArg ? 0 : Format->getFirstArg() - 1; 475 476 // The way the format attribute works in GCC, the implicit this argument 477 // of member functions is counted. However, it doesn't appear in our own 478 // lists, so decrement format_idx in that case. 479 if (IsCXXMember) { 480 if(FSI->FormatIdx == 0) 481 return false; 482 --FSI->FormatIdx; 483 if (FSI->FirstDataArg != 0) 484 --FSI->FirstDataArg; 485 } 486 return true; 487} 488 489/// Handles the checks for format strings, non-POD arguments to vararg 490/// functions, and NULL arguments passed to non-NULL parameters. 491void Sema::checkCall(NamedDecl *FDecl, Expr **Args, 492 unsigned NumArgs, 493 unsigned NumProtoArgs, 494 bool IsMemberFunction, 495 SourceLocation Loc, 496 SourceRange Range, 497 VariadicCallType CallType) { 498 // FIXME: This mechanism should be abstracted to be less fragile and 499 // more efficient. For example, just map function ids to custom 500 // handlers. 501 502 // Printf and scanf checking. 503 bool HandledFormatString = false; 504 for (specific_attr_iterator<FormatAttr> 505 I = FDecl->specific_attr_begin<FormatAttr>(), 506 E = FDecl->specific_attr_end<FormatAttr>(); I != E ; ++I) 507 if (CheckFormatArguments(*I, Args, NumArgs, IsMemberFunction, CallType, 508 Loc, Range)) 509 HandledFormatString = true; 510 511 // Refuse POD arguments that weren't caught by the format string 512 // checks above. 513 if (!HandledFormatString && CallType != VariadicDoesNotApply) 514 for (unsigned ArgIdx = NumProtoArgs; ArgIdx < NumArgs; ++ArgIdx) 515 variadicArgumentPODCheck(Args[ArgIdx], CallType); 516 517 for (specific_attr_iterator<NonNullAttr> 518 I = FDecl->specific_attr_begin<NonNullAttr>(), 519 E = FDecl->specific_attr_end<NonNullAttr>(); I != E; ++I) 520 CheckNonNullArguments(*I, Args, Loc); 521 522 // Type safety checking. 523 for (specific_attr_iterator<ArgumentWithTypeTagAttr> 524 i = FDecl->specific_attr_begin<ArgumentWithTypeTagAttr>(), 525 e = FDecl->specific_attr_end<ArgumentWithTypeTagAttr>(); i != e; ++i) { 526 CheckArgumentWithTypeTag(*i, Args); 527 } 528} 529 530/// CheckConstructorCall - Check a constructor call for correctness and safety 531/// properties not enforced by the C type system. 532void Sema::CheckConstructorCall(FunctionDecl *FDecl, Expr **Args, 533 unsigned NumArgs, 534 const FunctionProtoType *Proto, 535 SourceLocation Loc) { 536 VariadicCallType CallType = 537 Proto->isVariadic() ? VariadicConstructor : VariadicDoesNotApply; 538 checkCall(FDecl, Args, NumArgs, Proto->getNumArgs(), 539 /*IsMemberFunction=*/true, Loc, SourceRange(), CallType); 540} 541 542/// CheckFunctionCall - Check a direct function call for various correctness 543/// and safety properties not strictly enforced by the C type system. 544bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall, 545 const FunctionProtoType *Proto) { 546 bool IsMemberFunction = isa<CXXMemberCallExpr>(TheCall); 547 VariadicCallType CallType = getVariadicCallType(FDecl, Proto, 548 TheCall->getCallee()); 549 unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0; 550 checkCall(FDecl, TheCall->getArgs(), TheCall->getNumArgs(), NumProtoArgs, 551 IsMemberFunction, TheCall->getRParenLoc(), 552 TheCall->getCallee()->getSourceRange(), CallType); 553 554 IdentifierInfo *FnInfo = FDecl->getIdentifier(); 555 // None of the checks below are needed for functions that don't have 556 // simple names (e.g., C++ conversion functions). 557 if (!FnInfo) 558 return false; 559 560 unsigned CMId = FDecl->getMemoryFunctionKind(); 561 if (CMId == 0) 562 return false; 563 564 // Handle memory setting and copying functions. 565 if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat) 566 CheckStrlcpycatArguments(TheCall, FnInfo); 567 else if (CMId == Builtin::BIstrncat) 568 CheckStrncatArguments(TheCall, FnInfo); 569 else 570 CheckMemaccessArguments(TheCall, CMId, FnInfo); 571 572 return false; 573} 574 575bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac, 576 Expr **Args, unsigned NumArgs) { 577 VariadicCallType CallType = 578 Method->isVariadic() ? VariadicMethod : VariadicDoesNotApply; 579 580 checkCall(Method, Args, NumArgs, Method->param_size(), 581 /*IsMemberFunction=*/false, 582 lbrac, Method->getSourceRange(), CallType); 583 584 return false; 585} 586 587bool Sema::CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall, 588 const FunctionProtoType *Proto) { 589 const VarDecl *V = dyn_cast<VarDecl>(NDecl); 590 if (!V) 591 return false; 592 593 QualType Ty = V->getType(); 594 if (!Ty->isBlockPointerType()) 595 return false; 596 597 VariadicCallType CallType = 598 Proto && Proto->isVariadic() ? VariadicBlock : VariadicDoesNotApply ; 599 unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0; 600 601 checkCall(NDecl, TheCall->getArgs(), TheCall->getNumArgs(), 602 NumProtoArgs, /*IsMemberFunction=*/false, 603 TheCall->getRParenLoc(), 604 TheCall->getCallee()->getSourceRange(), CallType); 605 606 return false; 607} 608 609ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult, 610 AtomicExpr::AtomicOp Op) { 611 CallExpr *TheCall = cast<CallExpr>(TheCallResult.get()); 612 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 613 614 // All these operations take one of the following forms: 615 enum { 616 // C __c11_atomic_init(A *, C) 617 Init, 618 // C __c11_atomic_load(A *, int) 619 Load, 620 // void __atomic_load(A *, CP, int) 621 Copy, 622 // C __c11_atomic_add(A *, M, int) 623 Arithmetic, 624 // C __atomic_exchange_n(A *, CP, int) 625 Xchg, 626 // void __atomic_exchange(A *, C *, CP, int) 627 GNUXchg, 628 // bool __c11_atomic_compare_exchange_strong(A *, C *, CP, int, int) 629 C11CmpXchg, 630 // bool __atomic_compare_exchange(A *, C *, CP, bool, int, int) 631 GNUCmpXchg 632 } Form = Init; 633 const unsigned NumArgs[] = { 2, 2, 3, 3, 3, 4, 5, 6 }; 634 const unsigned NumVals[] = { 1, 0, 1, 1, 1, 2, 2, 3 }; 635 // where: 636 // C is an appropriate type, 637 // A is volatile _Atomic(C) for __c11 builtins and is C for GNU builtins, 638 // CP is C for __c11 builtins and GNU _n builtins and is C * otherwise, 639 // M is C if C is an integer, and ptrdiff_t if C is a pointer, and 640 // the int parameters are for orderings. 641 642 assert(AtomicExpr::AO__c11_atomic_init == 0 && 643 AtomicExpr::AO__c11_atomic_fetch_xor + 1 == AtomicExpr::AO__atomic_load 644 && "need to update code for modified C11 atomics"); 645 bool IsC11 = Op >= AtomicExpr::AO__c11_atomic_init && 646 Op <= AtomicExpr::AO__c11_atomic_fetch_xor; 647 bool IsN = Op == AtomicExpr::AO__atomic_load_n || 648 Op == AtomicExpr::AO__atomic_store_n || 649 Op == AtomicExpr::AO__atomic_exchange_n || 650 Op == AtomicExpr::AO__atomic_compare_exchange_n; 651 bool IsAddSub = false; 652 653 switch (Op) { 654 case AtomicExpr::AO__c11_atomic_init: 655 Form = Init; 656 break; 657 658 case AtomicExpr::AO__c11_atomic_load: 659 case AtomicExpr::AO__atomic_load_n: 660 Form = Load; 661 break; 662 663 case AtomicExpr::AO__c11_atomic_store: 664 case AtomicExpr::AO__atomic_load: 665 case AtomicExpr::AO__atomic_store: 666 case AtomicExpr::AO__atomic_store_n: 667 Form = Copy; 668 break; 669 670 case AtomicExpr::AO__c11_atomic_fetch_add: 671 case AtomicExpr::AO__c11_atomic_fetch_sub: 672 case AtomicExpr::AO__atomic_fetch_add: 673 case AtomicExpr::AO__atomic_fetch_sub: 674 case AtomicExpr::AO__atomic_add_fetch: 675 case AtomicExpr::AO__atomic_sub_fetch: 676 IsAddSub = true; 677 // Fall through. 678 case AtomicExpr::AO__c11_atomic_fetch_and: 679 case AtomicExpr::AO__c11_atomic_fetch_or: 680 case AtomicExpr::AO__c11_atomic_fetch_xor: 681 case AtomicExpr::AO__atomic_fetch_and: 682 case AtomicExpr::AO__atomic_fetch_or: 683 case AtomicExpr::AO__atomic_fetch_xor: 684 case AtomicExpr::AO__atomic_fetch_nand: 685 case AtomicExpr::AO__atomic_and_fetch: 686 case AtomicExpr::AO__atomic_or_fetch: 687 case AtomicExpr::AO__atomic_xor_fetch: 688 case AtomicExpr::AO__atomic_nand_fetch: 689 Form = Arithmetic; 690 break; 691 692 case AtomicExpr::AO__c11_atomic_exchange: 693 case AtomicExpr::AO__atomic_exchange_n: 694 Form = Xchg; 695 break; 696 697 case AtomicExpr::AO__atomic_exchange: 698 Form = GNUXchg; 699 break; 700 701 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 702 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 703 Form = C11CmpXchg; 704 break; 705 706 case AtomicExpr::AO__atomic_compare_exchange: 707 case AtomicExpr::AO__atomic_compare_exchange_n: 708 Form = GNUCmpXchg; 709 break; 710 } 711 712 // Check we have the right number of arguments. 713 if (TheCall->getNumArgs() < NumArgs[Form]) { 714 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 715 << 0 << NumArgs[Form] << TheCall->getNumArgs() 716 << TheCall->getCallee()->getSourceRange(); 717 return ExprError(); 718 } else if (TheCall->getNumArgs() > NumArgs[Form]) { 719 Diag(TheCall->getArg(NumArgs[Form])->getLocStart(), 720 diag::err_typecheck_call_too_many_args) 721 << 0 << NumArgs[Form] << TheCall->getNumArgs() 722 << TheCall->getCallee()->getSourceRange(); 723 return ExprError(); 724 } 725 726 // Inspect the first argument of the atomic operation. 727 Expr *Ptr = TheCall->getArg(0); 728 Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get(); 729 const PointerType *pointerType = Ptr->getType()->getAs<PointerType>(); 730 if (!pointerType) { 731 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 732 << Ptr->getType() << Ptr->getSourceRange(); 733 return ExprError(); 734 } 735 736 // For a __c11 builtin, this should be a pointer to an _Atomic type. 737 QualType AtomTy = pointerType->getPointeeType(); // 'A' 738 QualType ValType = AtomTy; // 'C' 739 if (IsC11) { 740 if (!AtomTy->isAtomicType()) { 741 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic) 742 << Ptr->getType() << Ptr->getSourceRange(); 743 return ExprError(); 744 } 745 ValType = AtomTy->getAs<AtomicType>()->getValueType(); 746 } 747 748 // For an arithmetic operation, the implied arithmetic must be well-formed. 749 if (Form == Arithmetic) { 750 // gcc does not enforce these rules for GNU atomics, but we do so for sanity. 751 if (IsAddSub && !ValType->isIntegerType() && !ValType->isPointerType()) { 752 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 753 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 754 return ExprError(); 755 } 756 if (!IsAddSub && !ValType->isIntegerType()) { 757 Diag(DRE->getLocStart(), diag::err_atomic_op_bitwise_needs_atomic_int) 758 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 759 return ExprError(); 760 } 761 } else if (IsN && !ValType->isIntegerType() && !ValType->isPointerType()) { 762 // For __atomic_*_n operations, the value type must be a scalar integral or 763 // pointer type which is 1, 2, 4, 8 or 16 bytes in length. 764 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 765 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 766 return ExprError(); 767 } 768 769 if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context)) { 770 // For GNU atomics, require a trivially-copyable type. This is not part of 771 // the GNU atomics specification, but we enforce it for sanity. 772 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_trivial_copy) 773 << Ptr->getType() << Ptr->getSourceRange(); 774 return ExprError(); 775 } 776 777 // FIXME: For any builtin other than a load, the ValType must not be 778 // const-qualified. 779 780 switch (ValType.getObjCLifetime()) { 781 case Qualifiers::OCL_None: 782 case Qualifiers::OCL_ExplicitNone: 783 // okay 784 break; 785 786 case Qualifiers::OCL_Weak: 787 case Qualifiers::OCL_Strong: 788 case Qualifiers::OCL_Autoreleasing: 789 // FIXME: Can this happen? By this point, ValType should be known 790 // to be trivially copyable. 791 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 792 << ValType << Ptr->getSourceRange(); 793 return ExprError(); 794 } 795 796 QualType ResultType = ValType; 797 if (Form == Copy || Form == GNUXchg || Form == Init) 798 ResultType = Context.VoidTy; 799 else if (Form == C11CmpXchg || Form == GNUCmpXchg) 800 ResultType = Context.BoolTy; 801 802 // The type of a parameter passed 'by value'. In the GNU atomics, such 803 // arguments are actually passed as pointers. 804 QualType ByValType = ValType; // 'CP' 805 if (!IsC11 && !IsN) 806 ByValType = Ptr->getType(); 807 808 // The first argument --- the pointer --- has a fixed type; we 809 // deduce the types of the rest of the arguments accordingly. Walk 810 // the remaining arguments, converting them to the deduced value type. 811 for (unsigned i = 1; i != NumArgs[Form]; ++i) { 812 QualType Ty; 813 if (i < NumVals[Form] + 1) { 814 switch (i) { 815 case 1: 816 // The second argument is the non-atomic operand. For arithmetic, this 817 // is always passed by value, and for a compare_exchange it is always 818 // passed by address. For the rest, GNU uses by-address and C11 uses 819 // by-value. 820 assert(Form != Load); 821 if (Form == Init || (Form == Arithmetic && ValType->isIntegerType())) 822 Ty = ValType; 823 else if (Form == Copy || Form == Xchg) 824 Ty = ByValType; 825 else if (Form == Arithmetic) 826 Ty = Context.getPointerDiffType(); 827 else 828 Ty = Context.getPointerType(ValType.getUnqualifiedType()); 829 break; 830 case 2: 831 // The third argument to compare_exchange / GNU exchange is a 832 // (pointer to a) desired value. 833 Ty = ByValType; 834 break; 835 case 3: 836 // The fourth argument to GNU compare_exchange is a 'weak' flag. 837 Ty = Context.BoolTy; 838 break; 839 } 840 } else { 841 // The order(s) are always converted to int. 842 Ty = Context.IntTy; 843 } 844 845 InitializedEntity Entity = 846 InitializedEntity::InitializeParameter(Context, Ty, false); 847 ExprResult Arg = TheCall->getArg(i); 848 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 849 if (Arg.isInvalid()) 850 return true; 851 TheCall->setArg(i, Arg.get()); 852 } 853 854 // Permute the arguments into a 'consistent' order. 855 SmallVector<Expr*, 5> SubExprs; 856 SubExprs.push_back(Ptr); 857 switch (Form) { 858 case Init: 859 // Note, AtomicExpr::getVal1() has a special case for this atomic. 860 SubExprs.push_back(TheCall->getArg(1)); // Val1 861 break; 862 case Load: 863 SubExprs.push_back(TheCall->getArg(1)); // Order 864 break; 865 case Copy: 866 case Arithmetic: 867 case Xchg: 868 SubExprs.push_back(TheCall->getArg(2)); // Order 869 SubExprs.push_back(TheCall->getArg(1)); // Val1 870 break; 871 case GNUXchg: 872 // Note, AtomicExpr::getVal2() has a special case for this atomic. 873 SubExprs.push_back(TheCall->getArg(3)); // Order 874 SubExprs.push_back(TheCall->getArg(1)); // Val1 875 SubExprs.push_back(TheCall->getArg(2)); // Val2 876 break; 877 case C11CmpXchg: 878 SubExprs.push_back(TheCall->getArg(3)); // Order 879 SubExprs.push_back(TheCall->getArg(1)); // Val1 880 SubExprs.push_back(TheCall->getArg(4)); // OrderFail 881 SubExprs.push_back(TheCall->getArg(2)); // Val2 882 break; 883 case GNUCmpXchg: 884 SubExprs.push_back(TheCall->getArg(4)); // Order 885 SubExprs.push_back(TheCall->getArg(1)); // Val1 886 SubExprs.push_back(TheCall->getArg(5)); // OrderFail 887 SubExprs.push_back(TheCall->getArg(2)); // Val2 888 SubExprs.push_back(TheCall->getArg(3)); // Weak 889 break; 890 } 891 892 return Owned(new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(), 893 SubExprs, ResultType, Op, 894 TheCall->getRParenLoc())); 895} 896 897 898/// checkBuiltinArgument - Given a call to a builtin function, perform 899/// normal type-checking on the given argument, updating the call in 900/// place. This is useful when a builtin function requires custom 901/// type-checking for some of its arguments but not necessarily all of 902/// them. 903/// 904/// Returns true on error. 905static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) { 906 FunctionDecl *Fn = E->getDirectCallee(); 907 assert(Fn && "builtin call without direct callee!"); 908 909 ParmVarDecl *Param = Fn->getParamDecl(ArgIndex); 910 InitializedEntity Entity = 911 InitializedEntity::InitializeParameter(S.Context, Param); 912 913 ExprResult Arg = E->getArg(0); 914 Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg); 915 if (Arg.isInvalid()) 916 return true; 917 918 E->setArg(ArgIndex, Arg.take()); 919 return false; 920} 921 922/// SemaBuiltinAtomicOverloaded - We have a call to a function like 923/// __sync_fetch_and_add, which is an overloaded function based on the pointer 924/// type of its first argument. The main ActOnCallExpr routines have already 925/// promoted the types of arguments because all of these calls are prototyped as 926/// void(...). 927/// 928/// This function goes through and does final semantic checking for these 929/// builtins, 930ExprResult 931Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) { 932 CallExpr *TheCall = (CallExpr *)TheCallResult.get(); 933 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 934 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 935 936 // Ensure that we have at least one argument to do type inference from. 937 if (TheCall->getNumArgs() < 1) { 938 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 939 << 0 << 1 << TheCall->getNumArgs() 940 << TheCall->getCallee()->getSourceRange(); 941 return ExprError(); 942 } 943 944 // Inspect the first argument of the atomic builtin. This should always be 945 // a pointer type, whose element is an integral scalar or pointer type. 946 // Because it is a pointer type, we don't have to worry about any implicit 947 // casts here. 948 // FIXME: We don't allow floating point scalars as input. 949 Expr *FirstArg = TheCall->getArg(0); 950 ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg); 951 if (FirstArgResult.isInvalid()) 952 return ExprError(); 953 FirstArg = FirstArgResult.take(); 954 TheCall->setArg(0, FirstArg); 955 956 const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>(); 957 if (!pointerType) { 958 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 959 << FirstArg->getType() << FirstArg->getSourceRange(); 960 return ExprError(); 961 } 962 963 QualType ValType = pointerType->getPointeeType(); 964 if (!ValType->isIntegerType() && !ValType->isAnyPointerType() && 965 !ValType->isBlockPointerType()) { 966 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr) 967 << FirstArg->getType() << FirstArg->getSourceRange(); 968 return ExprError(); 969 } 970 971 switch (ValType.getObjCLifetime()) { 972 case Qualifiers::OCL_None: 973 case Qualifiers::OCL_ExplicitNone: 974 // okay 975 break; 976 977 case Qualifiers::OCL_Weak: 978 case Qualifiers::OCL_Strong: 979 case Qualifiers::OCL_Autoreleasing: 980 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 981 << ValType << FirstArg->getSourceRange(); 982 return ExprError(); 983 } 984 985 // Strip any qualifiers off ValType. 986 ValType = ValType.getUnqualifiedType(); 987 988 // The majority of builtins return a value, but a few have special return 989 // types, so allow them to override appropriately below. 990 QualType ResultType = ValType; 991 992 // We need to figure out which concrete builtin this maps onto. For example, 993 // __sync_fetch_and_add with a 2 byte object turns into 994 // __sync_fetch_and_add_2. 995#define BUILTIN_ROW(x) \ 996 { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \ 997 Builtin::BI##x##_8, Builtin::BI##x##_16 } 998 999 static const unsigned BuiltinIndices[][5] = { 1000 BUILTIN_ROW(__sync_fetch_and_add), 1001 BUILTIN_ROW(__sync_fetch_and_sub), 1002 BUILTIN_ROW(__sync_fetch_and_or), 1003 BUILTIN_ROW(__sync_fetch_and_and), 1004 BUILTIN_ROW(__sync_fetch_and_xor), 1005 1006 BUILTIN_ROW(__sync_add_and_fetch), 1007 BUILTIN_ROW(__sync_sub_and_fetch), 1008 BUILTIN_ROW(__sync_and_and_fetch), 1009 BUILTIN_ROW(__sync_or_and_fetch), 1010 BUILTIN_ROW(__sync_xor_and_fetch), 1011 1012 BUILTIN_ROW(__sync_val_compare_and_swap), 1013 BUILTIN_ROW(__sync_bool_compare_and_swap), 1014 BUILTIN_ROW(__sync_lock_test_and_set), 1015 BUILTIN_ROW(__sync_lock_release), 1016 BUILTIN_ROW(__sync_swap) 1017 }; 1018#undef BUILTIN_ROW 1019 1020 // Determine the index of the size. 1021 unsigned SizeIndex; 1022 switch (Context.getTypeSizeInChars(ValType).getQuantity()) { 1023 case 1: SizeIndex = 0; break; 1024 case 2: SizeIndex = 1; break; 1025 case 4: SizeIndex = 2; break; 1026 case 8: SizeIndex = 3; break; 1027 case 16: SizeIndex = 4; break; 1028 default: 1029 Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size) 1030 << FirstArg->getType() << FirstArg->getSourceRange(); 1031 return ExprError(); 1032 } 1033 1034 // Each of these builtins has one pointer argument, followed by some number of 1035 // values (0, 1 or 2) followed by a potentially empty varags list of stuff 1036 // that we ignore. Find out which row of BuiltinIndices to read from as well 1037 // as the number of fixed args. 1038 unsigned BuiltinID = FDecl->getBuiltinID(); 1039 unsigned BuiltinIndex, NumFixed = 1; 1040 switch (BuiltinID) { 1041 default: llvm_unreachable("Unknown overloaded atomic builtin!"); 1042 case Builtin::BI__sync_fetch_and_add: 1043 case Builtin::BI__sync_fetch_and_add_1: 1044 case Builtin::BI__sync_fetch_and_add_2: 1045 case Builtin::BI__sync_fetch_and_add_4: 1046 case Builtin::BI__sync_fetch_and_add_8: 1047 case Builtin::BI__sync_fetch_and_add_16: 1048 BuiltinIndex = 0; 1049 break; 1050 1051 case Builtin::BI__sync_fetch_and_sub: 1052 case Builtin::BI__sync_fetch_and_sub_1: 1053 case Builtin::BI__sync_fetch_and_sub_2: 1054 case Builtin::BI__sync_fetch_and_sub_4: 1055 case Builtin::BI__sync_fetch_and_sub_8: 1056 case Builtin::BI__sync_fetch_and_sub_16: 1057 BuiltinIndex = 1; 1058 break; 1059 1060 case Builtin::BI__sync_fetch_and_or: 1061 case Builtin::BI__sync_fetch_and_or_1: 1062 case Builtin::BI__sync_fetch_and_or_2: 1063 case Builtin::BI__sync_fetch_and_or_4: 1064 case Builtin::BI__sync_fetch_and_or_8: 1065 case Builtin::BI__sync_fetch_and_or_16: 1066 BuiltinIndex = 2; 1067 break; 1068 1069 case Builtin::BI__sync_fetch_and_and: 1070 case Builtin::BI__sync_fetch_and_and_1: 1071 case Builtin::BI__sync_fetch_and_and_2: 1072 case Builtin::BI__sync_fetch_and_and_4: 1073 case Builtin::BI__sync_fetch_and_and_8: 1074 case Builtin::BI__sync_fetch_and_and_16: 1075 BuiltinIndex = 3; 1076 break; 1077 1078 case Builtin::BI__sync_fetch_and_xor: 1079 case Builtin::BI__sync_fetch_and_xor_1: 1080 case Builtin::BI__sync_fetch_and_xor_2: 1081 case Builtin::BI__sync_fetch_and_xor_4: 1082 case Builtin::BI__sync_fetch_and_xor_8: 1083 case Builtin::BI__sync_fetch_and_xor_16: 1084 BuiltinIndex = 4; 1085 break; 1086 1087 case Builtin::BI__sync_add_and_fetch: 1088 case Builtin::BI__sync_add_and_fetch_1: 1089 case Builtin::BI__sync_add_and_fetch_2: 1090 case Builtin::BI__sync_add_and_fetch_4: 1091 case Builtin::BI__sync_add_and_fetch_8: 1092 case Builtin::BI__sync_add_and_fetch_16: 1093 BuiltinIndex = 5; 1094 break; 1095 1096 case Builtin::BI__sync_sub_and_fetch: 1097 case Builtin::BI__sync_sub_and_fetch_1: 1098 case Builtin::BI__sync_sub_and_fetch_2: 1099 case Builtin::BI__sync_sub_and_fetch_4: 1100 case Builtin::BI__sync_sub_and_fetch_8: 1101 case Builtin::BI__sync_sub_and_fetch_16: 1102 BuiltinIndex = 6; 1103 break; 1104 1105 case Builtin::BI__sync_and_and_fetch: 1106 case Builtin::BI__sync_and_and_fetch_1: 1107 case Builtin::BI__sync_and_and_fetch_2: 1108 case Builtin::BI__sync_and_and_fetch_4: 1109 case Builtin::BI__sync_and_and_fetch_8: 1110 case Builtin::BI__sync_and_and_fetch_16: 1111 BuiltinIndex = 7; 1112 break; 1113 1114 case Builtin::BI__sync_or_and_fetch: 1115 case Builtin::BI__sync_or_and_fetch_1: 1116 case Builtin::BI__sync_or_and_fetch_2: 1117 case Builtin::BI__sync_or_and_fetch_4: 1118 case Builtin::BI__sync_or_and_fetch_8: 1119 case Builtin::BI__sync_or_and_fetch_16: 1120 BuiltinIndex = 8; 1121 break; 1122 1123 case Builtin::BI__sync_xor_and_fetch: 1124 case Builtin::BI__sync_xor_and_fetch_1: 1125 case Builtin::BI__sync_xor_and_fetch_2: 1126 case Builtin::BI__sync_xor_and_fetch_4: 1127 case Builtin::BI__sync_xor_and_fetch_8: 1128 case Builtin::BI__sync_xor_and_fetch_16: 1129 BuiltinIndex = 9; 1130 break; 1131 1132 case Builtin::BI__sync_val_compare_and_swap: 1133 case Builtin::BI__sync_val_compare_and_swap_1: 1134 case Builtin::BI__sync_val_compare_and_swap_2: 1135 case Builtin::BI__sync_val_compare_and_swap_4: 1136 case Builtin::BI__sync_val_compare_and_swap_8: 1137 case Builtin::BI__sync_val_compare_and_swap_16: 1138 BuiltinIndex = 10; 1139 NumFixed = 2; 1140 break; 1141 1142 case Builtin::BI__sync_bool_compare_and_swap: 1143 case Builtin::BI__sync_bool_compare_and_swap_1: 1144 case Builtin::BI__sync_bool_compare_and_swap_2: 1145 case Builtin::BI__sync_bool_compare_and_swap_4: 1146 case Builtin::BI__sync_bool_compare_and_swap_8: 1147 case Builtin::BI__sync_bool_compare_and_swap_16: 1148 BuiltinIndex = 11; 1149 NumFixed = 2; 1150 ResultType = Context.BoolTy; 1151 break; 1152 1153 case Builtin::BI__sync_lock_test_and_set: 1154 case Builtin::BI__sync_lock_test_and_set_1: 1155 case Builtin::BI__sync_lock_test_and_set_2: 1156 case Builtin::BI__sync_lock_test_and_set_4: 1157 case Builtin::BI__sync_lock_test_and_set_8: 1158 case Builtin::BI__sync_lock_test_and_set_16: 1159 BuiltinIndex = 12; 1160 break; 1161 1162 case Builtin::BI__sync_lock_release: 1163 case Builtin::BI__sync_lock_release_1: 1164 case Builtin::BI__sync_lock_release_2: 1165 case Builtin::BI__sync_lock_release_4: 1166 case Builtin::BI__sync_lock_release_8: 1167 case Builtin::BI__sync_lock_release_16: 1168 BuiltinIndex = 13; 1169 NumFixed = 0; 1170 ResultType = Context.VoidTy; 1171 break; 1172 1173 case Builtin::BI__sync_swap: 1174 case Builtin::BI__sync_swap_1: 1175 case Builtin::BI__sync_swap_2: 1176 case Builtin::BI__sync_swap_4: 1177 case Builtin::BI__sync_swap_8: 1178 case Builtin::BI__sync_swap_16: 1179 BuiltinIndex = 14; 1180 break; 1181 } 1182 1183 // Now that we know how many fixed arguments we expect, first check that we 1184 // have at least that many. 1185 if (TheCall->getNumArgs() < 1+NumFixed) { 1186 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 1187 << 0 << 1+NumFixed << TheCall->getNumArgs() 1188 << TheCall->getCallee()->getSourceRange(); 1189 return ExprError(); 1190 } 1191 1192 // Get the decl for the concrete builtin from this, we can tell what the 1193 // concrete integer type we should convert to is. 1194 unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex]; 1195 const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID); 1196 IdentifierInfo *NewBuiltinII = PP.getIdentifierInfo(NewBuiltinName); 1197 FunctionDecl *NewBuiltinDecl = 1198 cast<FunctionDecl>(LazilyCreateBuiltin(NewBuiltinII, NewBuiltinID, 1199 TUScope, false, DRE->getLocStart())); 1200 1201 // The first argument --- the pointer --- has a fixed type; we 1202 // deduce the types of the rest of the arguments accordingly. Walk 1203 // the remaining arguments, converting them to the deduced value type. 1204 for (unsigned i = 0; i != NumFixed; ++i) { 1205 ExprResult Arg = TheCall->getArg(i+1); 1206 1207 // GCC does an implicit conversion to the pointer or integer ValType. This 1208 // can fail in some cases (1i -> int**), check for this error case now. 1209 // Initialize the argument. 1210 InitializedEntity Entity = InitializedEntity::InitializeParameter(Context, 1211 ValType, /*consume*/ false); 1212 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 1213 if (Arg.isInvalid()) 1214 return ExprError(); 1215 1216 // Okay, we have something that *can* be converted to the right type. Check 1217 // to see if there is a potentially weird extension going on here. This can 1218 // happen when you do an atomic operation on something like an char* and 1219 // pass in 42. The 42 gets converted to char. This is even more strange 1220 // for things like 45.123 -> char, etc. 1221 // FIXME: Do this check. 1222 TheCall->setArg(i+1, Arg.take()); 1223 } 1224 1225 ASTContext& Context = this->getASTContext(); 1226 1227 // Create a new DeclRefExpr to refer to the new decl. 1228 DeclRefExpr* NewDRE = DeclRefExpr::Create( 1229 Context, 1230 DRE->getQualifierLoc(), 1231 SourceLocation(), 1232 NewBuiltinDecl, 1233 /*enclosing*/ false, 1234 DRE->getLocation(), 1235 Context.BuiltinFnTy, 1236 DRE->getValueKind()); 1237 1238 // Set the callee in the CallExpr. 1239 // FIXME: This loses syntactic information. 1240 QualType CalleePtrTy = Context.getPointerType(NewBuiltinDecl->getType()); 1241 ExprResult PromotedCall = ImpCastExprToType(NewDRE, CalleePtrTy, 1242 CK_BuiltinFnToFnPtr); 1243 TheCall->setCallee(PromotedCall.take()); 1244 1245 // Change the result type of the call to match the original value type. This 1246 // is arbitrary, but the codegen for these builtins ins design to handle it 1247 // gracefully. 1248 TheCall->setType(ResultType); 1249 1250 return TheCallResult; 1251} 1252 1253/// CheckObjCString - Checks that the argument to the builtin 1254/// CFString constructor is correct 1255/// Note: It might also make sense to do the UTF-16 conversion here (would 1256/// simplify the backend). 1257bool Sema::CheckObjCString(Expr *Arg) { 1258 Arg = Arg->IgnoreParenCasts(); 1259 StringLiteral *Literal = dyn_cast<StringLiteral>(Arg); 1260 1261 if (!Literal || !Literal->isAscii()) { 1262 Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant) 1263 << Arg->getSourceRange(); 1264 return true; 1265 } 1266 1267 if (Literal->containsNonAsciiOrNull()) { 1268 StringRef String = Literal->getString(); 1269 unsigned NumBytes = String.size(); 1270 SmallVector<UTF16, 128> ToBuf(NumBytes); 1271 const UTF8 *FromPtr = (const UTF8 *)String.data(); 1272 UTF16 *ToPtr = &ToBuf[0]; 1273 1274 ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, 1275 &ToPtr, ToPtr + NumBytes, 1276 strictConversion); 1277 // Check for conversion failure. 1278 if (Result != conversionOK) 1279 Diag(Arg->getLocStart(), 1280 diag::warn_cfstring_truncated) << Arg->getSourceRange(); 1281 } 1282 return false; 1283} 1284 1285/// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity. 1286/// Emit an error and return true on failure, return false on success. 1287bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) { 1288 Expr *Fn = TheCall->getCallee(); 1289 if (TheCall->getNumArgs() > 2) { 1290 Diag(TheCall->getArg(2)->getLocStart(), 1291 diag::err_typecheck_call_too_many_args) 1292 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1293 << Fn->getSourceRange() 1294 << SourceRange(TheCall->getArg(2)->getLocStart(), 1295 (*(TheCall->arg_end()-1))->getLocEnd()); 1296 return true; 1297 } 1298 1299 if (TheCall->getNumArgs() < 2) { 1300 return Diag(TheCall->getLocEnd(), 1301 diag::err_typecheck_call_too_few_args_at_least) 1302 << 0 /*function call*/ << 2 << TheCall->getNumArgs(); 1303 } 1304 1305 // Type-check the first argument normally. 1306 if (checkBuiltinArgument(*this, TheCall, 0)) 1307 return true; 1308 1309 // Determine whether the current function is variadic or not. 1310 BlockScopeInfo *CurBlock = getCurBlock(); 1311 bool isVariadic; 1312 if (CurBlock) 1313 isVariadic = CurBlock->TheDecl->isVariadic(); 1314 else if (FunctionDecl *FD = getCurFunctionDecl()) 1315 isVariadic = FD->isVariadic(); 1316 else 1317 isVariadic = getCurMethodDecl()->isVariadic(); 1318 1319 if (!isVariadic) { 1320 Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function); 1321 return true; 1322 } 1323 1324 // Verify that the second argument to the builtin is the last argument of the 1325 // current function or method. 1326 bool SecondArgIsLastNamedArgument = false; 1327 const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts(); 1328 1329 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) { 1330 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) { 1331 // FIXME: This isn't correct for methods (results in bogus warning). 1332 // Get the last formal in the current function. 1333 const ParmVarDecl *LastArg; 1334 if (CurBlock) 1335 LastArg = *(CurBlock->TheDecl->param_end()-1); 1336 else if (FunctionDecl *FD = getCurFunctionDecl()) 1337 LastArg = *(FD->param_end()-1); 1338 else 1339 LastArg = *(getCurMethodDecl()->param_end()-1); 1340 SecondArgIsLastNamedArgument = PV == LastArg; 1341 } 1342 } 1343 1344 if (!SecondArgIsLastNamedArgument) 1345 Diag(TheCall->getArg(1)->getLocStart(), 1346 diag::warn_second_parameter_of_va_start_not_last_named_argument); 1347 return false; 1348} 1349 1350/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and 1351/// friends. This is declared to take (...), so we have to check everything. 1352bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) { 1353 if (TheCall->getNumArgs() < 2) 1354 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 1355 << 0 << 2 << TheCall->getNumArgs()/*function call*/; 1356 if (TheCall->getNumArgs() > 2) 1357 return Diag(TheCall->getArg(2)->getLocStart(), 1358 diag::err_typecheck_call_too_many_args) 1359 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1360 << SourceRange(TheCall->getArg(2)->getLocStart(), 1361 (*(TheCall->arg_end()-1))->getLocEnd()); 1362 1363 ExprResult OrigArg0 = TheCall->getArg(0); 1364 ExprResult OrigArg1 = TheCall->getArg(1); 1365 1366 // Do standard promotions between the two arguments, returning their common 1367 // type. 1368 QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false); 1369 if (OrigArg0.isInvalid() || OrigArg1.isInvalid()) 1370 return true; 1371 1372 // Make sure any conversions are pushed back into the call; this is 1373 // type safe since unordered compare builtins are declared as "_Bool 1374 // foo(...)". 1375 TheCall->setArg(0, OrigArg0.get()); 1376 TheCall->setArg(1, OrigArg1.get()); 1377 1378 if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent()) 1379 return false; 1380 1381 // If the common type isn't a real floating type, then the arguments were 1382 // invalid for this operation. 1383 if (Res.isNull() || !Res->isRealFloatingType()) 1384 return Diag(OrigArg0.get()->getLocStart(), 1385 diag::err_typecheck_call_invalid_ordered_compare) 1386 << OrigArg0.get()->getType() << OrigArg1.get()->getType() 1387 << SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd()); 1388 1389 return false; 1390} 1391 1392/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like 1393/// __builtin_isnan and friends. This is declared to take (...), so we have 1394/// to check everything. We expect the last argument to be a floating point 1395/// value. 1396bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) { 1397 if (TheCall->getNumArgs() < NumArgs) 1398 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 1399 << 0 << NumArgs << TheCall->getNumArgs()/*function call*/; 1400 if (TheCall->getNumArgs() > NumArgs) 1401 return Diag(TheCall->getArg(NumArgs)->getLocStart(), 1402 diag::err_typecheck_call_too_many_args) 1403 << 0 /*function call*/ << NumArgs << TheCall->getNumArgs() 1404 << SourceRange(TheCall->getArg(NumArgs)->getLocStart(), 1405 (*(TheCall->arg_end()-1))->getLocEnd()); 1406 1407 Expr *OrigArg = TheCall->getArg(NumArgs-1); 1408 1409 if (OrigArg->isTypeDependent()) 1410 return false; 1411 1412 // This operation requires a non-_Complex floating-point number. 1413 if (!OrigArg->getType()->isRealFloatingType()) 1414 return Diag(OrigArg->getLocStart(), 1415 diag::err_typecheck_call_invalid_unary_fp) 1416 << OrigArg->getType() << OrigArg->getSourceRange(); 1417 1418 // If this is an implicit conversion from float -> double, remove it. 1419 if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) { 1420 Expr *CastArg = Cast->getSubExpr(); 1421 if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) { 1422 assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) && 1423 "promotion from float to double is the only expected cast here"); 1424 Cast->setSubExpr(0); 1425 TheCall->setArg(NumArgs-1, CastArg); 1426 } 1427 } 1428 1429 return false; 1430} 1431 1432/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector. 1433// This is declared to take (...), so we have to check everything. 1434ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) { 1435 if (TheCall->getNumArgs() < 2) 1436 return ExprError(Diag(TheCall->getLocEnd(), 1437 diag::err_typecheck_call_too_few_args_at_least) 1438 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1439 << TheCall->getSourceRange()); 1440 1441 // Determine which of the following types of shufflevector we're checking: 1442 // 1) unary, vector mask: (lhs, mask) 1443 // 2) binary, vector mask: (lhs, rhs, mask) 1444 // 3) binary, scalar mask: (lhs, rhs, index, ..., index) 1445 QualType resType = TheCall->getArg(0)->getType(); 1446 unsigned numElements = 0; 1447 1448 if (!TheCall->getArg(0)->isTypeDependent() && 1449 !TheCall->getArg(1)->isTypeDependent()) { 1450 QualType LHSType = TheCall->getArg(0)->getType(); 1451 QualType RHSType = TheCall->getArg(1)->getType(); 1452 1453 if (!LHSType->isVectorType() || !RHSType->isVectorType()) { 1454 Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector) 1455 << SourceRange(TheCall->getArg(0)->getLocStart(), 1456 TheCall->getArg(1)->getLocEnd()); 1457 return ExprError(); 1458 } 1459 1460 numElements = LHSType->getAs<VectorType>()->getNumElements(); 1461 unsigned numResElements = TheCall->getNumArgs() - 2; 1462 1463 // Check to see if we have a call with 2 vector arguments, the unary shuffle 1464 // with mask. If so, verify that RHS is an integer vector type with the 1465 // same number of elts as lhs. 1466 if (TheCall->getNumArgs() == 2) { 1467 if (!RHSType->hasIntegerRepresentation() || 1468 RHSType->getAs<VectorType>()->getNumElements() != numElements) 1469 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 1470 << SourceRange(TheCall->getArg(1)->getLocStart(), 1471 TheCall->getArg(1)->getLocEnd()); 1472 numResElements = numElements; 1473 } 1474 else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) { 1475 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 1476 << SourceRange(TheCall->getArg(0)->getLocStart(), 1477 TheCall->getArg(1)->getLocEnd()); 1478 return ExprError(); 1479 } else if (numElements != numResElements) { 1480 QualType eltType = LHSType->getAs<VectorType>()->getElementType(); 1481 resType = Context.getVectorType(eltType, numResElements, 1482 VectorType::GenericVector); 1483 } 1484 } 1485 1486 for (unsigned i = 2; i < TheCall->getNumArgs(); i++) { 1487 if (TheCall->getArg(i)->isTypeDependent() || 1488 TheCall->getArg(i)->isValueDependent()) 1489 continue; 1490 1491 llvm::APSInt Result(32); 1492 if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context)) 1493 return ExprError(Diag(TheCall->getLocStart(), 1494 diag::err_shufflevector_nonconstant_argument) 1495 << TheCall->getArg(i)->getSourceRange()); 1496 1497 if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2) 1498 return ExprError(Diag(TheCall->getLocStart(), 1499 diag::err_shufflevector_argument_too_large) 1500 << TheCall->getArg(i)->getSourceRange()); 1501 } 1502 1503 SmallVector<Expr*, 32> exprs; 1504 1505 for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) { 1506 exprs.push_back(TheCall->getArg(i)); 1507 TheCall->setArg(i, 0); 1508 } 1509 1510 return Owned(new (Context) ShuffleVectorExpr(Context, exprs, resType, 1511 TheCall->getCallee()->getLocStart(), 1512 TheCall->getRParenLoc())); 1513} 1514 1515/// SemaBuiltinPrefetch - Handle __builtin_prefetch. 1516// This is declared to take (const void*, ...) and can take two 1517// optional constant int args. 1518bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) { 1519 unsigned NumArgs = TheCall->getNumArgs(); 1520 1521 if (NumArgs > 3) 1522 return Diag(TheCall->getLocEnd(), 1523 diag::err_typecheck_call_too_many_args_at_most) 1524 << 0 /*function call*/ << 3 << NumArgs 1525 << TheCall->getSourceRange(); 1526 1527 // Argument 0 is checked for us and the remaining arguments must be 1528 // constant integers. 1529 for (unsigned i = 1; i != NumArgs; ++i) { 1530 Expr *Arg = TheCall->getArg(i); 1531 1532 // We can't check the value of a dependent argument. 1533 if (Arg->isTypeDependent() || Arg->isValueDependent()) 1534 continue; 1535 1536 llvm::APSInt Result; 1537 if (SemaBuiltinConstantArg(TheCall, i, Result)) 1538 return true; 1539 1540 // FIXME: gcc issues a warning and rewrites these to 0. These 1541 // seems especially odd for the third argument since the default 1542 // is 3. 1543 if (i == 1) { 1544 if (Result.getLimitedValue() > 1) 1545 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1546 << "0" << "1" << Arg->getSourceRange(); 1547 } else { 1548 if (Result.getLimitedValue() > 3) 1549 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1550 << "0" << "3" << Arg->getSourceRange(); 1551 } 1552 } 1553 1554 return false; 1555} 1556 1557/// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr 1558/// TheCall is a constant expression. 1559bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum, 1560 llvm::APSInt &Result) { 1561 Expr *Arg = TheCall->getArg(ArgNum); 1562 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 1563 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 1564 1565 if (Arg->isTypeDependent() || Arg->isValueDependent()) return false; 1566 1567 if (!Arg->isIntegerConstantExpr(Result, Context)) 1568 return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type) 1569 << FDecl->getDeclName() << Arg->getSourceRange(); 1570 1571 return false; 1572} 1573 1574/// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr, 1575/// int type). This simply type checks that type is one of the defined 1576/// constants (0-3). 1577// For compatibility check 0-3, llvm only handles 0 and 2. 1578bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) { 1579 llvm::APSInt Result; 1580 1581 // We can't check the value of a dependent argument. 1582 if (TheCall->getArg(1)->isTypeDependent() || 1583 TheCall->getArg(1)->isValueDependent()) 1584 return false; 1585 1586 // Check constant-ness first. 1587 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 1588 return true; 1589 1590 Expr *Arg = TheCall->getArg(1); 1591 if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) { 1592 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1593 << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 1594 } 1595 1596 return false; 1597} 1598 1599/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val). 1600/// This checks that val is a constant 1. 1601bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) { 1602 Expr *Arg = TheCall->getArg(1); 1603 llvm::APSInt Result; 1604 1605 // TODO: This is less than ideal. Overload this to take a value. 1606 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 1607 return true; 1608 1609 if (Result != 1) 1610 return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val) 1611 << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 1612 1613 return false; 1614} 1615 1616// Determine if an expression is a string literal or constant string. 1617// If this function returns false on the arguments to a function expecting a 1618// format string, we will usually need to emit a warning. 1619// True string literals are then checked by CheckFormatString. 1620Sema::StringLiteralCheckType 1621Sema::checkFormatStringExpr(const Expr *E, Expr **Args, 1622 unsigned NumArgs, bool HasVAListArg, 1623 unsigned format_idx, unsigned firstDataArg, 1624 FormatStringType Type, VariadicCallType CallType, 1625 bool inFunctionCall) { 1626 tryAgain: 1627 if (E->isTypeDependent() || E->isValueDependent()) 1628 return SLCT_NotALiteral; 1629 1630 E = E->IgnoreParenCasts(); 1631 1632 if (E->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull)) 1633 // Technically -Wformat-nonliteral does not warn about this case. 1634 // The behavior of printf and friends in this case is implementation 1635 // dependent. Ideally if the format string cannot be null then 1636 // it should have a 'nonnull' attribute in the function prototype. 1637 return SLCT_CheckedLiteral; 1638 1639 switch (E->getStmtClass()) { 1640 case Stmt::BinaryConditionalOperatorClass: 1641 case Stmt::ConditionalOperatorClass: { 1642 // The expression is a literal if both sub-expressions were, and it was 1643 // completely checked only if both sub-expressions were checked. 1644 const AbstractConditionalOperator *C = 1645 cast<AbstractConditionalOperator>(E); 1646 StringLiteralCheckType Left = 1647 checkFormatStringExpr(C->getTrueExpr(), Args, NumArgs, 1648 HasVAListArg, format_idx, firstDataArg, 1649 Type, CallType, inFunctionCall); 1650 if (Left == SLCT_NotALiteral) 1651 return SLCT_NotALiteral; 1652 StringLiteralCheckType Right = 1653 checkFormatStringExpr(C->getFalseExpr(), Args, NumArgs, 1654 HasVAListArg, format_idx, firstDataArg, 1655 Type, CallType, inFunctionCall); 1656 return Left < Right ? Left : Right; 1657 } 1658 1659 case Stmt::ImplicitCastExprClass: { 1660 E = cast<ImplicitCastExpr>(E)->getSubExpr(); 1661 goto tryAgain; 1662 } 1663 1664 case Stmt::OpaqueValueExprClass: 1665 if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) { 1666 E = src; 1667 goto tryAgain; 1668 } 1669 return SLCT_NotALiteral; 1670 1671 case Stmt::PredefinedExprClass: 1672 // While __func__, etc., are technically not string literals, they 1673 // cannot contain format specifiers and thus are not a security 1674 // liability. 1675 return SLCT_UncheckedLiteral; 1676 1677 case Stmt::DeclRefExprClass: { 1678 const DeclRefExpr *DR = cast<DeclRefExpr>(E); 1679 1680 // As an exception, do not flag errors for variables binding to 1681 // const string literals. 1682 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) { 1683 bool isConstant = false; 1684 QualType T = DR->getType(); 1685 1686 if (const ArrayType *AT = Context.getAsArrayType(T)) { 1687 isConstant = AT->getElementType().isConstant(Context); 1688 } else if (const PointerType *PT = T->getAs<PointerType>()) { 1689 isConstant = T.isConstant(Context) && 1690 PT->getPointeeType().isConstant(Context); 1691 } else if (T->isObjCObjectPointerType()) { 1692 // In ObjC, there is usually no "const ObjectPointer" type, 1693 // so don't check if the pointee type is constant. 1694 isConstant = T.isConstant(Context); 1695 } 1696 1697 if (isConstant) { 1698 if (const Expr *Init = VD->getAnyInitializer()) { 1699 // Look through initializers like const char c[] = { "foo" } 1700 if (const InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) { 1701 if (InitList->isStringLiteralInit()) 1702 Init = InitList->getInit(0)->IgnoreParenImpCasts(); 1703 } 1704 return checkFormatStringExpr(Init, Args, NumArgs, 1705 HasVAListArg, format_idx, 1706 firstDataArg, Type, CallType, 1707 /*inFunctionCall*/false); 1708 } 1709 } 1710 1711 // For vprintf* functions (i.e., HasVAListArg==true), we add a 1712 // special check to see if the format string is a function parameter 1713 // of the function calling the printf function. If the function 1714 // has an attribute indicating it is a printf-like function, then we 1715 // should suppress warnings concerning non-literals being used in a call 1716 // to a vprintf function. For example: 1717 // 1718 // void 1719 // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){ 1720 // va_list ap; 1721 // va_start(ap, fmt); 1722 // vprintf(fmt, ap); // Do NOT emit a warning about "fmt". 1723 // ... 1724 // 1725 if (HasVAListArg) { 1726 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(VD)) { 1727 if (const NamedDecl *ND = dyn_cast<NamedDecl>(PV->getDeclContext())) { 1728 int PVIndex = PV->getFunctionScopeIndex() + 1; 1729 for (specific_attr_iterator<FormatAttr> 1730 i = ND->specific_attr_begin<FormatAttr>(), 1731 e = ND->specific_attr_end<FormatAttr>(); i != e ; ++i) { 1732 FormatAttr *PVFormat = *i; 1733 // adjust for implicit parameter 1734 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 1735 if (MD->isInstance()) 1736 ++PVIndex; 1737 // We also check if the formats are compatible. 1738 // We can't pass a 'scanf' string to a 'printf' function. 1739 if (PVIndex == PVFormat->getFormatIdx() && 1740 Type == GetFormatStringType(PVFormat)) 1741 return SLCT_UncheckedLiteral; 1742 } 1743 } 1744 } 1745 } 1746 } 1747 1748 return SLCT_NotALiteral; 1749 } 1750 1751 case Stmt::CallExprClass: 1752 case Stmt::CXXMemberCallExprClass: { 1753 const CallExpr *CE = cast<CallExpr>(E); 1754 if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) { 1755 if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) { 1756 unsigned ArgIndex = FA->getFormatIdx(); 1757 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 1758 if (MD->isInstance()) 1759 --ArgIndex; 1760 const Expr *Arg = CE->getArg(ArgIndex - 1); 1761 1762 return checkFormatStringExpr(Arg, Args, NumArgs, 1763 HasVAListArg, format_idx, firstDataArg, 1764 Type, CallType, inFunctionCall); 1765 } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) { 1766 unsigned BuiltinID = FD->getBuiltinID(); 1767 if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString || 1768 BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) { 1769 const Expr *Arg = CE->getArg(0); 1770 return checkFormatStringExpr(Arg, Args, NumArgs, 1771 HasVAListArg, format_idx, 1772 firstDataArg, Type, CallType, 1773 inFunctionCall); 1774 } 1775 } 1776 } 1777 1778 return SLCT_NotALiteral; 1779 } 1780 case Stmt::ObjCStringLiteralClass: 1781 case Stmt::StringLiteralClass: { 1782 const StringLiteral *StrE = NULL; 1783 1784 if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E)) 1785 StrE = ObjCFExpr->getString(); 1786 else 1787 StrE = cast<StringLiteral>(E); 1788 1789 if (StrE) { 1790 CheckFormatString(StrE, E, Args, NumArgs, HasVAListArg, format_idx, 1791 firstDataArg, Type, inFunctionCall, CallType); 1792 return SLCT_CheckedLiteral; 1793 } 1794 1795 return SLCT_NotALiteral; 1796 } 1797 1798 default: 1799 return SLCT_NotALiteral; 1800 } 1801} 1802 1803void 1804Sema::CheckNonNullArguments(const NonNullAttr *NonNull, 1805 const Expr * const *ExprArgs, 1806 SourceLocation CallSiteLoc) { 1807 for (NonNullAttr::args_iterator i = NonNull->args_begin(), 1808 e = NonNull->args_end(); 1809 i != e; ++i) { 1810 const Expr *ArgExpr = ExprArgs[*i]; 1811 if (ArgExpr->isNullPointerConstant(Context, 1812 Expr::NPC_ValueDependentIsNotNull)) 1813 Diag(CallSiteLoc, diag::warn_null_arg) << ArgExpr->getSourceRange(); 1814 } 1815} 1816 1817Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) { 1818 return llvm::StringSwitch<FormatStringType>(Format->getType()) 1819 .Case("scanf", FST_Scanf) 1820 .Cases("printf", "printf0", FST_Printf) 1821 .Cases("NSString", "CFString", FST_NSString) 1822 .Case("strftime", FST_Strftime) 1823 .Case("strfmon", FST_Strfmon) 1824 .Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf) 1825 .Default(FST_Unknown); 1826} 1827 1828/// CheckFormatArguments - Check calls to printf and scanf (and similar 1829/// functions) for correct use of format strings. 1830/// Returns true if a format string has been fully checked. 1831bool Sema::CheckFormatArguments(const FormatAttr *Format, Expr **Args, 1832 unsigned NumArgs, bool IsCXXMember, 1833 VariadicCallType CallType, 1834 SourceLocation Loc, SourceRange Range) { 1835 FormatStringInfo FSI; 1836 if (getFormatStringInfo(Format, IsCXXMember, &FSI)) 1837 return CheckFormatArguments(Args, NumArgs, FSI.HasVAListArg, FSI.FormatIdx, 1838 FSI.FirstDataArg, GetFormatStringType(Format), 1839 CallType, Loc, Range); 1840 return false; 1841} 1842 1843bool Sema::CheckFormatArguments(Expr **Args, unsigned NumArgs, 1844 bool HasVAListArg, unsigned format_idx, 1845 unsigned firstDataArg, FormatStringType Type, 1846 VariadicCallType CallType, 1847 SourceLocation Loc, SourceRange Range) { 1848 // CHECK: printf/scanf-like function is called with no format string. 1849 if (format_idx >= NumArgs) { 1850 Diag(Loc, diag::warn_missing_format_string) << Range; 1851 return false; 1852 } 1853 1854 const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts(); 1855 1856 // CHECK: format string is not a string literal. 1857 // 1858 // Dynamically generated format strings are difficult to 1859 // automatically vet at compile time. Requiring that format strings 1860 // are string literals: (1) permits the checking of format strings by 1861 // the compiler and thereby (2) can practically remove the source of 1862 // many format string exploits. 1863 1864 // Format string can be either ObjC string (e.g. @"%d") or 1865 // C string (e.g. "%d") 1866 // ObjC string uses the same format specifiers as C string, so we can use 1867 // the same format string checking logic for both ObjC and C strings. 1868 StringLiteralCheckType CT = 1869 checkFormatStringExpr(OrigFormatExpr, Args, NumArgs, HasVAListArg, 1870 format_idx, firstDataArg, Type, CallType); 1871 if (CT != SLCT_NotALiteral) 1872 // Literal format string found, check done! 1873 return CT == SLCT_CheckedLiteral; 1874 1875 // Strftime is particular as it always uses a single 'time' argument, 1876 // so it is safe to pass a non-literal string. 1877 if (Type == FST_Strftime) 1878 return false; 1879 1880 // Do not emit diag when the string param is a macro expansion and the 1881 // format is either NSString or CFString. This is a hack to prevent 1882 // diag when using the NSLocalizedString and CFCopyLocalizedString macros 1883 // which are usually used in place of NS and CF string literals. 1884 if (Type == FST_NSString && 1885 SourceMgr.isInSystemMacro(Args[format_idx]->getLocStart())) 1886 return false; 1887 1888 // If there are no arguments specified, warn with -Wformat-security, otherwise 1889 // warn only with -Wformat-nonliteral. 1890 if (NumArgs == format_idx+1) 1891 Diag(Args[format_idx]->getLocStart(), 1892 diag::warn_format_nonliteral_noargs) 1893 << OrigFormatExpr->getSourceRange(); 1894 else 1895 Diag(Args[format_idx]->getLocStart(), 1896 diag::warn_format_nonliteral) 1897 << OrigFormatExpr->getSourceRange(); 1898 return false; 1899} 1900 1901namespace { 1902class CheckFormatHandler : public analyze_format_string::FormatStringHandler { 1903protected: 1904 Sema &S; 1905 const StringLiteral *FExpr; 1906 const Expr *OrigFormatExpr; 1907 const unsigned FirstDataArg; 1908 const unsigned NumDataArgs; 1909 const char *Beg; // Start of format string. 1910 const bool HasVAListArg; 1911 const Expr * const *Args; 1912 const unsigned NumArgs; 1913 unsigned FormatIdx; 1914 llvm::BitVector CoveredArgs; 1915 bool usesPositionalArgs; 1916 bool atFirstArg; 1917 bool inFunctionCall; 1918 Sema::VariadicCallType CallType; 1919public: 1920 CheckFormatHandler(Sema &s, const StringLiteral *fexpr, 1921 const Expr *origFormatExpr, unsigned firstDataArg, 1922 unsigned numDataArgs, const char *beg, bool hasVAListArg, 1923 Expr **args, unsigned numArgs, 1924 unsigned formatIdx, bool inFunctionCall, 1925 Sema::VariadicCallType callType) 1926 : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr), 1927 FirstDataArg(firstDataArg), NumDataArgs(numDataArgs), 1928 Beg(beg), HasVAListArg(hasVAListArg), 1929 Args(args), NumArgs(numArgs), FormatIdx(formatIdx), 1930 usesPositionalArgs(false), atFirstArg(true), 1931 inFunctionCall(inFunctionCall), CallType(callType) { 1932 CoveredArgs.resize(numDataArgs); 1933 CoveredArgs.reset(); 1934 } 1935 1936 void DoneProcessing(); 1937 1938 void HandleIncompleteSpecifier(const char *startSpecifier, 1939 unsigned specifierLen); 1940 1941 void HandleInvalidLengthModifier( 1942 const analyze_format_string::FormatSpecifier &FS, 1943 const analyze_format_string::ConversionSpecifier &CS, 1944 const char *startSpecifier, unsigned specifierLen, unsigned DiagID); 1945 1946 void HandleNonStandardLengthModifier( 1947 const analyze_format_string::FormatSpecifier &FS, 1948 const char *startSpecifier, unsigned specifierLen); 1949 1950 void HandleNonStandardConversionSpecifier( 1951 const analyze_format_string::ConversionSpecifier &CS, 1952 const char *startSpecifier, unsigned specifierLen); 1953 1954 virtual void HandlePosition(const char *startPos, unsigned posLen); 1955 1956 virtual void HandleInvalidPosition(const char *startSpecifier, 1957 unsigned specifierLen, 1958 analyze_format_string::PositionContext p); 1959 1960 virtual void HandleZeroPosition(const char *startPos, unsigned posLen); 1961 1962 void HandleNullChar(const char *nullCharacter); 1963 1964 template <typename Range> 1965 static void EmitFormatDiagnostic(Sema &S, bool inFunctionCall, 1966 const Expr *ArgumentExpr, 1967 PartialDiagnostic PDiag, 1968 SourceLocation StringLoc, 1969 bool IsStringLocation, Range StringRange, 1970 ArrayRef<FixItHint> Fixit = ArrayRef<FixItHint>()); 1971 1972protected: 1973 bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc, 1974 const char *startSpec, 1975 unsigned specifierLen, 1976 const char *csStart, unsigned csLen); 1977 1978 void HandlePositionalNonpositionalArgs(SourceLocation Loc, 1979 const char *startSpec, 1980 unsigned specifierLen); 1981 1982 SourceRange getFormatStringRange(); 1983 CharSourceRange getSpecifierRange(const char *startSpecifier, 1984 unsigned specifierLen); 1985 SourceLocation getLocationOfByte(const char *x); 1986 1987 const Expr *getDataArg(unsigned i) const; 1988 1989 bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS, 1990 const analyze_format_string::ConversionSpecifier &CS, 1991 const char *startSpecifier, unsigned specifierLen, 1992 unsigned argIndex); 1993 1994 template <typename Range> 1995 void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc, 1996 bool IsStringLocation, Range StringRange, 1997 ArrayRef<FixItHint> Fixit = ArrayRef<FixItHint>()); 1998 1999 void CheckPositionalAndNonpositionalArgs( 2000 const analyze_format_string::FormatSpecifier *FS); 2001}; 2002} 2003 2004SourceRange CheckFormatHandler::getFormatStringRange() { 2005 return OrigFormatExpr->getSourceRange(); 2006} 2007 2008CharSourceRange CheckFormatHandler:: 2009getSpecifierRange(const char *startSpecifier, unsigned specifierLen) { 2010 SourceLocation Start = getLocationOfByte(startSpecifier); 2011 SourceLocation End = getLocationOfByte(startSpecifier + specifierLen - 1); 2012 2013 // Advance the end SourceLocation by one due to half-open ranges. 2014 End = End.getLocWithOffset(1); 2015 2016 return CharSourceRange::getCharRange(Start, End); 2017} 2018 2019SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) { 2020 return S.getLocationOfStringLiteralByte(FExpr, x - Beg); 2021} 2022 2023void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier, 2024 unsigned specifierLen){ 2025 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier), 2026 getLocationOfByte(startSpecifier), 2027 /*IsStringLocation*/true, 2028 getSpecifierRange(startSpecifier, specifierLen)); 2029} 2030 2031void CheckFormatHandler::HandleInvalidLengthModifier( 2032 const analyze_format_string::FormatSpecifier &FS, 2033 const analyze_format_string::ConversionSpecifier &CS, 2034 const char *startSpecifier, unsigned specifierLen, unsigned DiagID) { 2035 using namespace analyze_format_string; 2036 2037 const LengthModifier &LM = FS.getLengthModifier(); 2038 CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength()); 2039 2040 // See if we know how to fix this length modifier. 2041 llvm::Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier(); 2042 if (FixedLM) { 2043 EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(), 2044 getLocationOfByte(LM.getStart()), 2045 /*IsStringLocation*/true, 2046 getSpecifierRange(startSpecifier, specifierLen)); 2047 2048 S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier) 2049 << FixedLM->toString() 2050 << FixItHint::CreateReplacement(LMRange, FixedLM->toString()); 2051 2052 } else { 2053 FixItHint Hint; 2054 if (DiagID == diag::warn_format_nonsensical_length) 2055 Hint = FixItHint::CreateRemoval(LMRange); 2056 2057 EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(), 2058 getLocationOfByte(LM.getStart()), 2059 /*IsStringLocation*/true, 2060 getSpecifierRange(startSpecifier, specifierLen), 2061 Hint); 2062 } 2063} 2064 2065void CheckFormatHandler::HandleNonStandardLengthModifier( 2066 const analyze_format_string::FormatSpecifier &FS, 2067 const char *startSpecifier, unsigned specifierLen) { 2068 using namespace analyze_format_string; 2069 2070 const LengthModifier &LM = FS.getLengthModifier(); 2071 CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength()); 2072 2073 // See if we know how to fix this length modifier. 2074 llvm::Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier(); 2075 if (FixedLM) { 2076 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2077 << LM.toString() << 0, 2078 getLocationOfByte(LM.getStart()), 2079 /*IsStringLocation*/true, 2080 getSpecifierRange(startSpecifier, specifierLen)); 2081 2082 S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier) 2083 << FixedLM->toString() 2084 << FixItHint::CreateReplacement(LMRange, FixedLM->toString()); 2085 2086 } else { 2087 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2088 << LM.toString() << 0, 2089 getLocationOfByte(LM.getStart()), 2090 /*IsStringLocation*/true, 2091 getSpecifierRange(startSpecifier, specifierLen)); 2092 } 2093} 2094 2095void CheckFormatHandler::HandleNonStandardConversionSpecifier( 2096 const analyze_format_string::ConversionSpecifier &CS, 2097 const char *startSpecifier, unsigned specifierLen) { 2098 using namespace analyze_format_string; 2099 2100 // See if we know how to fix this conversion specifier. 2101 llvm::Optional<ConversionSpecifier> FixedCS = CS.getStandardSpecifier(); 2102 if (FixedCS) { 2103 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2104 << CS.toString() << /*conversion specifier*/1, 2105 getLocationOfByte(CS.getStart()), 2106 /*IsStringLocation*/true, 2107 getSpecifierRange(startSpecifier, specifierLen)); 2108 2109 CharSourceRange CSRange = getSpecifierRange(CS.getStart(), CS.getLength()); 2110 S.Diag(getLocationOfByte(CS.getStart()), diag::note_format_fix_specifier) 2111 << FixedCS->toString() 2112 << FixItHint::CreateReplacement(CSRange, FixedCS->toString()); 2113 } else { 2114 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2115 << CS.toString() << /*conversion specifier*/1, 2116 getLocationOfByte(CS.getStart()), 2117 /*IsStringLocation*/true, 2118 getSpecifierRange(startSpecifier, specifierLen)); 2119 } 2120} 2121 2122void CheckFormatHandler::HandlePosition(const char *startPos, 2123 unsigned posLen) { 2124 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg), 2125 getLocationOfByte(startPos), 2126 /*IsStringLocation*/true, 2127 getSpecifierRange(startPos, posLen)); 2128} 2129 2130void 2131CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen, 2132 analyze_format_string::PositionContext p) { 2133 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier) 2134 << (unsigned) p, 2135 getLocationOfByte(startPos), /*IsStringLocation*/true, 2136 getSpecifierRange(startPos, posLen)); 2137} 2138 2139void CheckFormatHandler::HandleZeroPosition(const char *startPos, 2140 unsigned posLen) { 2141 EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier), 2142 getLocationOfByte(startPos), 2143 /*IsStringLocation*/true, 2144 getSpecifierRange(startPos, posLen)); 2145} 2146 2147void CheckFormatHandler::HandleNullChar(const char *nullCharacter) { 2148 if (!isa<ObjCStringLiteral>(OrigFormatExpr)) { 2149 // The presence of a null character is likely an error. 2150 EmitFormatDiagnostic( 2151 S.PDiag(diag::warn_printf_format_string_contains_null_char), 2152 getLocationOfByte(nullCharacter), /*IsStringLocation*/true, 2153 getFormatStringRange()); 2154 } 2155} 2156 2157// Note that this may return NULL if there was an error parsing or building 2158// one of the argument expressions. 2159const Expr *CheckFormatHandler::getDataArg(unsigned i) const { 2160 return Args[FirstDataArg + i]; 2161} 2162 2163void CheckFormatHandler::DoneProcessing() { 2164 // Does the number of data arguments exceed the number of 2165 // format conversions in the format string? 2166 if (!HasVAListArg) { 2167 // Find any arguments that weren't covered. 2168 CoveredArgs.flip(); 2169 signed notCoveredArg = CoveredArgs.find_first(); 2170 if (notCoveredArg >= 0) { 2171 assert((unsigned)notCoveredArg < NumDataArgs); 2172 if (const Expr *E = getDataArg((unsigned) notCoveredArg)) { 2173 SourceLocation Loc = E->getLocStart(); 2174 if (!S.getSourceManager().isInSystemMacro(Loc)) { 2175 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_data_arg_not_used), 2176 Loc, /*IsStringLocation*/false, 2177 getFormatStringRange()); 2178 } 2179 } 2180 } 2181 } 2182} 2183 2184bool 2185CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex, 2186 SourceLocation Loc, 2187 const char *startSpec, 2188 unsigned specifierLen, 2189 const char *csStart, 2190 unsigned csLen) { 2191 2192 bool keepGoing = true; 2193 if (argIndex < NumDataArgs) { 2194 // Consider the argument coverered, even though the specifier doesn't 2195 // make sense. 2196 CoveredArgs.set(argIndex); 2197 } 2198 else { 2199 // If argIndex exceeds the number of data arguments we 2200 // don't issue a warning because that is just a cascade of warnings (and 2201 // they may have intended '%%' anyway). We don't want to continue processing 2202 // the format string after this point, however, as we will like just get 2203 // gibberish when trying to match arguments. 2204 keepGoing = false; 2205 } 2206 2207 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion) 2208 << StringRef(csStart, csLen), 2209 Loc, /*IsStringLocation*/true, 2210 getSpecifierRange(startSpec, specifierLen)); 2211 2212 return keepGoing; 2213} 2214 2215void 2216CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc, 2217 const char *startSpec, 2218 unsigned specifierLen) { 2219 EmitFormatDiagnostic( 2220 S.PDiag(diag::warn_format_mix_positional_nonpositional_args), 2221 Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen)); 2222} 2223 2224bool 2225CheckFormatHandler::CheckNumArgs( 2226 const analyze_format_string::FormatSpecifier &FS, 2227 const analyze_format_string::ConversionSpecifier &CS, 2228 const char *startSpecifier, unsigned specifierLen, unsigned argIndex) { 2229 2230 if (argIndex >= NumDataArgs) { 2231 PartialDiagnostic PDiag = FS.usesPositionalArg() 2232 ? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args) 2233 << (argIndex+1) << NumDataArgs) 2234 : S.PDiag(diag::warn_printf_insufficient_data_args); 2235 EmitFormatDiagnostic( 2236 PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true, 2237 getSpecifierRange(startSpecifier, specifierLen)); 2238 return false; 2239 } 2240 return true; 2241} 2242 2243template<typename Range> 2244void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag, 2245 SourceLocation Loc, 2246 bool IsStringLocation, 2247 Range StringRange, 2248 ArrayRef<FixItHint> FixIt) { 2249 EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag, 2250 Loc, IsStringLocation, StringRange, FixIt); 2251} 2252 2253/// \brief If the format string is not within the funcion call, emit a note 2254/// so that the function call and string are in diagnostic messages. 2255/// 2256/// \param InFunctionCall if true, the format string is within the function 2257/// call and only one diagnostic message will be produced. Otherwise, an 2258/// extra note will be emitted pointing to location of the format string. 2259/// 2260/// \param ArgumentExpr the expression that is passed as the format string 2261/// argument in the function call. Used for getting locations when two 2262/// diagnostics are emitted. 2263/// 2264/// \param PDiag the callee should already have provided any strings for the 2265/// diagnostic message. This function only adds locations and fixits 2266/// to diagnostics. 2267/// 2268/// \param Loc primary location for diagnostic. If two diagnostics are 2269/// required, one will be at Loc and a new SourceLocation will be created for 2270/// the other one. 2271/// 2272/// \param IsStringLocation if true, Loc points to the format string should be 2273/// used for the note. Otherwise, Loc points to the argument list and will 2274/// be used with PDiag. 2275/// 2276/// \param StringRange some or all of the string to highlight. This is 2277/// templated so it can accept either a CharSourceRange or a SourceRange. 2278/// 2279/// \param FixIt optional fix it hint for the format string. 2280template<typename Range> 2281void CheckFormatHandler::EmitFormatDiagnostic(Sema &S, bool InFunctionCall, 2282 const Expr *ArgumentExpr, 2283 PartialDiagnostic PDiag, 2284 SourceLocation Loc, 2285 bool IsStringLocation, 2286 Range StringRange, 2287 ArrayRef<FixItHint> FixIt) { 2288 if (InFunctionCall) { 2289 const Sema::SemaDiagnosticBuilder &D = S.Diag(Loc, PDiag); 2290 D << StringRange; 2291 for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end(); 2292 I != E; ++I) { 2293 D << *I; 2294 } 2295 } else { 2296 S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag) 2297 << ArgumentExpr->getSourceRange(); 2298 2299 const Sema::SemaDiagnosticBuilder &Note = 2300 S.Diag(IsStringLocation ? Loc : StringRange.getBegin(), 2301 diag::note_format_string_defined); 2302 2303 Note << StringRange; 2304 for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end(); 2305 I != E; ++I) { 2306 Note << *I; 2307 } 2308 } 2309} 2310 2311//===--- CHECK: Printf format string checking ------------------------------===// 2312 2313namespace { 2314class CheckPrintfHandler : public CheckFormatHandler { 2315 bool ObjCContext; 2316public: 2317 CheckPrintfHandler(Sema &s, const StringLiteral *fexpr, 2318 const Expr *origFormatExpr, unsigned firstDataArg, 2319 unsigned numDataArgs, bool isObjC, 2320 const char *beg, bool hasVAListArg, 2321 Expr **Args, unsigned NumArgs, 2322 unsigned formatIdx, bool inFunctionCall, 2323 Sema::VariadicCallType CallType) 2324 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 2325 numDataArgs, beg, hasVAListArg, Args, NumArgs, 2326 formatIdx, inFunctionCall, CallType), ObjCContext(isObjC) 2327 {} 2328 2329 2330 bool HandleInvalidPrintfConversionSpecifier( 2331 const analyze_printf::PrintfSpecifier &FS, 2332 const char *startSpecifier, 2333 unsigned specifierLen); 2334 2335 bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS, 2336 const char *startSpecifier, 2337 unsigned specifierLen); 2338 bool checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 2339 const char *StartSpecifier, 2340 unsigned SpecifierLen, 2341 const Expr *E); 2342 2343 bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k, 2344 const char *startSpecifier, unsigned specifierLen); 2345 void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS, 2346 const analyze_printf::OptionalAmount &Amt, 2347 unsigned type, 2348 const char *startSpecifier, unsigned specifierLen); 2349 void HandleFlag(const analyze_printf::PrintfSpecifier &FS, 2350 const analyze_printf::OptionalFlag &flag, 2351 const char *startSpecifier, unsigned specifierLen); 2352 void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS, 2353 const analyze_printf::OptionalFlag &ignoredFlag, 2354 const analyze_printf::OptionalFlag &flag, 2355 const char *startSpecifier, unsigned specifierLen); 2356 bool checkForCStrMembers(const analyze_printf::ArgType &AT, 2357 const Expr *E, const CharSourceRange &CSR); 2358 2359}; 2360} 2361 2362bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier( 2363 const analyze_printf::PrintfSpecifier &FS, 2364 const char *startSpecifier, 2365 unsigned specifierLen) { 2366 const analyze_printf::PrintfConversionSpecifier &CS = 2367 FS.getConversionSpecifier(); 2368 2369 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 2370 getLocationOfByte(CS.getStart()), 2371 startSpecifier, specifierLen, 2372 CS.getStart(), CS.getLength()); 2373} 2374 2375bool CheckPrintfHandler::HandleAmount( 2376 const analyze_format_string::OptionalAmount &Amt, 2377 unsigned k, const char *startSpecifier, 2378 unsigned specifierLen) { 2379 2380 if (Amt.hasDataArgument()) { 2381 if (!HasVAListArg) { 2382 unsigned argIndex = Amt.getArgIndex(); 2383 if (argIndex >= NumDataArgs) { 2384 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg) 2385 << k, 2386 getLocationOfByte(Amt.getStart()), 2387 /*IsStringLocation*/true, 2388 getSpecifierRange(startSpecifier, specifierLen)); 2389 // Don't do any more checking. We will just emit 2390 // spurious errors. 2391 return false; 2392 } 2393 2394 // Type check the data argument. It should be an 'int'. 2395 // Although not in conformance with C99, we also allow the argument to be 2396 // an 'unsigned int' as that is a reasonably safe case. GCC also 2397 // doesn't emit a warning for that case. 2398 CoveredArgs.set(argIndex); 2399 const Expr *Arg = getDataArg(argIndex); 2400 if (!Arg) 2401 return false; 2402 2403 QualType T = Arg->getType(); 2404 2405 const analyze_printf::ArgType &AT = Amt.getArgType(S.Context); 2406 assert(AT.isValid()); 2407 2408 if (!AT.matchesType(S.Context, T)) { 2409 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type) 2410 << k << AT.getRepresentativeTypeName(S.Context) 2411 << T << Arg->getSourceRange(), 2412 getLocationOfByte(Amt.getStart()), 2413 /*IsStringLocation*/true, 2414 getSpecifierRange(startSpecifier, specifierLen)); 2415 // Don't do any more checking. We will just emit 2416 // spurious errors. 2417 return false; 2418 } 2419 } 2420 } 2421 return true; 2422} 2423 2424void CheckPrintfHandler::HandleInvalidAmount( 2425 const analyze_printf::PrintfSpecifier &FS, 2426 const analyze_printf::OptionalAmount &Amt, 2427 unsigned type, 2428 const char *startSpecifier, 2429 unsigned specifierLen) { 2430 const analyze_printf::PrintfConversionSpecifier &CS = 2431 FS.getConversionSpecifier(); 2432 2433 FixItHint fixit = 2434 Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant 2435 ? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(), 2436 Amt.getConstantLength())) 2437 : FixItHint(); 2438 2439 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount) 2440 << type << CS.toString(), 2441 getLocationOfByte(Amt.getStart()), 2442 /*IsStringLocation*/true, 2443 getSpecifierRange(startSpecifier, specifierLen), 2444 fixit); 2445} 2446 2447void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS, 2448 const analyze_printf::OptionalFlag &flag, 2449 const char *startSpecifier, 2450 unsigned specifierLen) { 2451 // Warn about pointless flag with a fixit removal. 2452 const analyze_printf::PrintfConversionSpecifier &CS = 2453 FS.getConversionSpecifier(); 2454 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag) 2455 << flag.toString() << CS.toString(), 2456 getLocationOfByte(flag.getPosition()), 2457 /*IsStringLocation*/true, 2458 getSpecifierRange(startSpecifier, specifierLen), 2459 FixItHint::CreateRemoval( 2460 getSpecifierRange(flag.getPosition(), 1))); 2461} 2462 2463void CheckPrintfHandler::HandleIgnoredFlag( 2464 const analyze_printf::PrintfSpecifier &FS, 2465 const analyze_printf::OptionalFlag &ignoredFlag, 2466 const analyze_printf::OptionalFlag &flag, 2467 const char *startSpecifier, 2468 unsigned specifierLen) { 2469 // Warn about ignored flag with a fixit removal. 2470 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag) 2471 << ignoredFlag.toString() << flag.toString(), 2472 getLocationOfByte(ignoredFlag.getPosition()), 2473 /*IsStringLocation*/true, 2474 getSpecifierRange(startSpecifier, specifierLen), 2475 FixItHint::CreateRemoval( 2476 getSpecifierRange(ignoredFlag.getPosition(), 1))); 2477} 2478 2479// Determines if the specified is a C++ class or struct containing 2480// a member with the specified name and kind (e.g. a CXXMethodDecl named 2481// "c_str()"). 2482template<typename MemberKind> 2483static llvm::SmallPtrSet<MemberKind*, 1> 2484CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) { 2485 const RecordType *RT = Ty->getAs<RecordType>(); 2486 llvm::SmallPtrSet<MemberKind*, 1> Results; 2487 2488 if (!RT) 2489 return Results; 2490 const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()); 2491 if (!RD) 2492 return Results; 2493 2494 LookupResult R(S, &S.PP.getIdentifierTable().get(Name), SourceLocation(), 2495 Sema::LookupMemberName); 2496 2497 // We just need to include all members of the right kind turned up by the 2498 // filter, at this point. 2499 if (S.LookupQualifiedName(R, RT->getDecl())) 2500 for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) { 2501 NamedDecl *decl = (*I)->getUnderlyingDecl(); 2502 if (MemberKind *FK = dyn_cast<MemberKind>(decl)) 2503 Results.insert(FK); 2504 } 2505 return Results; 2506} 2507 2508// Check if a (w)string was passed when a (w)char* was needed, and offer a 2509// better diagnostic if so. AT is assumed to be valid. 2510// Returns true when a c_str() conversion method is found. 2511bool CheckPrintfHandler::checkForCStrMembers( 2512 const analyze_printf::ArgType &AT, const Expr *E, 2513 const CharSourceRange &CSR) { 2514 typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet; 2515 2516 MethodSet Results = 2517 CXXRecordMembersNamed<CXXMethodDecl>("c_str", S, E->getType()); 2518 2519 for (MethodSet::iterator MI = Results.begin(), ME = Results.end(); 2520 MI != ME; ++MI) { 2521 const CXXMethodDecl *Method = *MI; 2522 if (Method->getNumParams() == 0 && 2523 AT.matchesType(S.Context, Method->getResultType())) { 2524 // FIXME: Suggest parens if the expression needs them. 2525 SourceLocation EndLoc = 2526 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()); 2527 S.Diag(E->getLocStart(), diag::note_printf_c_str) 2528 << "c_str()" 2529 << FixItHint::CreateInsertion(EndLoc, ".c_str()"); 2530 return true; 2531 } 2532 } 2533 2534 return false; 2535} 2536 2537bool 2538CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier 2539 &FS, 2540 const char *startSpecifier, 2541 unsigned specifierLen) { 2542 2543 using namespace analyze_format_string; 2544 using namespace analyze_printf; 2545 const PrintfConversionSpecifier &CS = FS.getConversionSpecifier(); 2546 2547 if (FS.consumesDataArgument()) { 2548 if (atFirstArg) { 2549 atFirstArg = false; 2550 usesPositionalArgs = FS.usesPositionalArg(); 2551 } 2552 else if (usesPositionalArgs != FS.usesPositionalArg()) { 2553 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 2554 startSpecifier, specifierLen); 2555 return false; 2556 } 2557 } 2558 2559 // First check if the field width, precision, and conversion specifier 2560 // have matching data arguments. 2561 if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0, 2562 startSpecifier, specifierLen)) { 2563 return false; 2564 } 2565 2566 if (!HandleAmount(FS.getPrecision(), /* precision */ 1, 2567 startSpecifier, specifierLen)) { 2568 return false; 2569 } 2570 2571 if (!CS.consumesDataArgument()) { 2572 // FIXME: Technically specifying a precision or field width here 2573 // makes no sense. Worth issuing a warning at some point. 2574 return true; 2575 } 2576 2577 // Consume the argument. 2578 unsigned argIndex = FS.getArgIndex(); 2579 if (argIndex < NumDataArgs) { 2580 // The check to see if the argIndex is valid will come later. 2581 // We set the bit here because we may exit early from this 2582 // function if we encounter some other error. 2583 CoveredArgs.set(argIndex); 2584 } 2585 2586 // Check for using an Objective-C specific conversion specifier 2587 // in a non-ObjC literal. 2588 if (!ObjCContext && CS.isObjCArg()) { 2589 return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier, 2590 specifierLen); 2591 } 2592 2593 // Check for invalid use of field width 2594 if (!FS.hasValidFieldWidth()) { 2595 HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0, 2596 startSpecifier, specifierLen); 2597 } 2598 2599 // Check for invalid use of precision 2600 if (!FS.hasValidPrecision()) { 2601 HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1, 2602 startSpecifier, specifierLen); 2603 } 2604 2605 // Check each flag does not conflict with any other component. 2606 if (!FS.hasValidThousandsGroupingPrefix()) 2607 HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen); 2608 if (!FS.hasValidLeadingZeros()) 2609 HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen); 2610 if (!FS.hasValidPlusPrefix()) 2611 HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen); 2612 if (!FS.hasValidSpacePrefix()) 2613 HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen); 2614 if (!FS.hasValidAlternativeForm()) 2615 HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen); 2616 if (!FS.hasValidLeftJustified()) 2617 HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen); 2618 2619 // Check that flags are not ignored by another flag 2620 if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+' 2621 HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(), 2622 startSpecifier, specifierLen); 2623 if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-' 2624 HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(), 2625 startSpecifier, specifierLen); 2626 2627 // Check the length modifier is valid with the given conversion specifier. 2628 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 2629 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 2630 diag::warn_format_nonsensical_length); 2631 else if (!FS.hasStandardLengthModifier()) 2632 HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen); 2633 else if (!FS.hasStandardLengthConversionCombination()) 2634 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 2635 diag::warn_format_non_standard_conversion_spec); 2636 2637 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 2638 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 2639 2640 // The remaining checks depend on the data arguments. 2641 if (HasVAListArg) 2642 return true; 2643 2644 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 2645 return false; 2646 2647 const Expr *Arg = getDataArg(argIndex); 2648 if (!Arg) 2649 return true; 2650 2651 return checkFormatExpr(FS, startSpecifier, specifierLen, Arg); 2652} 2653 2654static bool requiresParensToAddCast(const Expr *E) { 2655 // FIXME: We should have a general way to reason about operator 2656 // precedence and whether parens are actually needed here. 2657 // Take care of a few common cases where they aren't. 2658 const Expr *Inside = E->IgnoreImpCasts(); 2659 if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Inside)) 2660 Inside = POE->getSyntacticForm()->IgnoreImpCasts(); 2661 2662 switch (Inside->getStmtClass()) { 2663 case Stmt::ArraySubscriptExprClass: 2664 case Stmt::CallExprClass: 2665 case Stmt::DeclRefExprClass: 2666 case Stmt::MemberExprClass: 2667 case Stmt::ObjCIvarRefExprClass: 2668 case Stmt::ObjCMessageExprClass: 2669 case Stmt::ObjCPropertyRefExprClass: 2670 case Stmt::ParenExprClass: 2671 case Stmt::UnaryOperatorClass: 2672 return false; 2673 default: 2674 return true; 2675 } 2676} 2677 2678bool 2679CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 2680 const char *StartSpecifier, 2681 unsigned SpecifierLen, 2682 const Expr *E) { 2683 using namespace analyze_format_string; 2684 using namespace analyze_printf; 2685 // Now type check the data expression that matches the 2686 // format specifier. 2687 const analyze_printf::ArgType &AT = FS.getArgType(S.Context, 2688 ObjCContext); 2689 if (!AT.isValid()) 2690 return true; 2691 2692 QualType IntendedTy = E->getType(); 2693 if (AT.matchesType(S.Context, IntendedTy)) 2694 return true; 2695 2696 // Look through argument promotions for our error message's reported type. 2697 // This includes the integral and floating promotions, but excludes array 2698 // and function pointer decay; seeing that an argument intended to be a 2699 // string has type 'char [6]' is probably more confusing than 'char *'. 2700 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 2701 if (ICE->getCastKind() == CK_IntegralCast || 2702 ICE->getCastKind() == CK_FloatingCast) { 2703 E = ICE->getSubExpr(); 2704 IntendedTy = E->getType(); 2705 2706 // Check if we didn't match because of an implicit cast from a 'char' 2707 // or 'short' to an 'int'. This is done because printf is a varargs 2708 // function. 2709 if (ICE->getType() == S.Context.IntTy || 2710 ICE->getType() == S.Context.UnsignedIntTy) { 2711 // All further checking is done on the subexpression. 2712 if (AT.matchesType(S.Context, IntendedTy)) 2713 return true; 2714 } 2715 } 2716 } 2717 2718 if (S.Context.getTargetInfo().getTriple().isOSDarwin()) { 2719 // Special-case some of Darwin's platform-independence types. 2720 if (const TypedefType *UserTy = IntendedTy->getAs<TypedefType>()) { 2721 StringRef Name = UserTy->getDecl()->getName(); 2722 IntendedTy = llvm::StringSwitch<QualType>(Name) 2723 .Case("NSInteger", S.Context.LongTy) 2724 .Case("NSUInteger", S.Context.UnsignedLongTy) 2725 .Case("SInt32", S.Context.IntTy) 2726 .Case("UInt32", S.Context.UnsignedIntTy) 2727 .Default(IntendedTy); 2728 } 2729 } 2730 2731 // We may be able to offer a FixItHint if it is a supported type. 2732 PrintfSpecifier fixedFS = FS; 2733 bool success = fixedFS.fixType(IntendedTy, S.getLangOpts(), 2734 S.Context, ObjCContext); 2735 2736 if (success) { 2737 // Get the fix string from the fixed format specifier 2738 SmallString<16> buf; 2739 llvm::raw_svector_ostream os(buf); 2740 fixedFS.toString(os); 2741 2742 CharSourceRange SpecRange = getSpecifierRange(StartSpecifier, SpecifierLen); 2743 2744 if (IntendedTy != E->getType()) { 2745 // The canonical type for formatting this value is different from the 2746 // actual type of the expression. (This occurs, for example, with Darwin's 2747 // NSInteger on 32-bit platforms, where it is typedef'd as 'int', but 2748 // should be printed as 'long' for 64-bit compatibility.) 2749 // Rather than emitting a normal format/argument mismatch, we want to 2750 // add a cast to the recommended type (and correct the format string 2751 // if necessary). 2752 SmallString<16> CastBuf; 2753 llvm::raw_svector_ostream CastFix(CastBuf); 2754 CastFix << "("; 2755 IntendedTy.print(CastFix, S.Context.getPrintingPolicy()); 2756 CastFix << ")"; 2757 2758 SmallVector<FixItHint,4> Hints; 2759 if (!AT.matchesType(S.Context, IntendedTy)) 2760 Hints.push_back(FixItHint::CreateReplacement(SpecRange, os.str())); 2761 2762 if (const CStyleCastExpr *CCast = dyn_cast<CStyleCastExpr>(E)) { 2763 // If there's already a cast present, just replace it. 2764 SourceRange CastRange(CCast->getLParenLoc(), CCast->getRParenLoc()); 2765 Hints.push_back(FixItHint::CreateReplacement(CastRange, CastFix.str())); 2766 2767 } else if (!requiresParensToAddCast(E)) { 2768 // If the expression has high enough precedence, 2769 // just write the C-style cast. 2770 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 2771 CastFix.str())); 2772 } else { 2773 // Otherwise, add parens around the expression as well as the cast. 2774 CastFix << "("; 2775 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 2776 CastFix.str())); 2777 2778 SourceLocation After = S.PP.getLocForEndOfToken(E->getLocEnd()); 2779 Hints.push_back(FixItHint::CreateInsertion(After, ")")); 2780 } 2781 2782 // We extract the name from the typedef because we don't want to show 2783 // the underlying type in the diagnostic. 2784 const TypedefType *UserTy = cast<TypedefType>(E->getType()); 2785 StringRef Name = UserTy->getDecl()->getName(); 2786 2787 // Finally, emit the diagnostic. 2788 EmitFormatDiagnostic(S.PDiag(diag::warn_format_argument_needs_cast) 2789 << Name << IntendedTy 2790 << E->getSourceRange(), 2791 E->getLocStart(), /*IsStringLocation=*/false, 2792 SpecRange, Hints); 2793 } else { 2794 EmitFormatDiagnostic( 2795 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2796 << AT.getRepresentativeTypeName(S.Context) << IntendedTy 2797 << E->getSourceRange(), 2798 E->getLocStart(), 2799 /*IsStringLocation*/false, 2800 SpecRange, 2801 FixItHint::CreateReplacement(SpecRange, os.str())); 2802 } 2803 } else { 2804 const CharSourceRange &CSR = getSpecifierRange(StartSpecifier, 2805 SpecifierLen); 2806 // Since the warning for passing non-POD types to variadic functions 2807 // was deferred until now, we emit a warning for non-POD 2808 // arguments here. 2809 if (S.isValidVarArgType(E->getType()) == Sema::VAK_Invalid) { 2810 unsigned DiagKind; 2811 if (E->getType()->isObjCObjectType()) 2812 DiagKind = diag::err_cannot_pass_objc_interface_to_vararg_format; 2813 else 2814 DiagKind = diag::warn_non_pod_vararg_with_format_string; 2815 2816 EmitFormatDiagnostic( 2817 S.PDiag(DiagKind) 2818 << S.getLangOpts().CPlusPlus0x 2819 << E->getType() 2820 << CallType 2821 << AT.getRepresentativeTypeName(S.Context) 2822 << CSR 2823 << E->getSourceRange(), 2824 E->getLocStart(), /*IsStringLocation*/false, CSR); 2825 2826 checkForCStrMembers(AT, E, CSR); 2827 } else 2828 EmitFormatDiagnostic( 2829 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2830 << AT.getRepresentativeTypeName(S.Context) << E->getType() 2831 << CSR 2832 << E->getSourceRange(), 2833 E->getLocStart(), /*IsStringLocation*/false, CSR); 2834 } 2835 2836 return true; 2837} 2838 2839//===--- CHECK: Scanf format string checking ------------------------------===// 2840 2841namespace { 2842class CheckScanfHandler : public CheckFormatHandler { 2843public: 2844 CheckScanfHandler(Sema &s, const StringLiteral *fexpr, 2845 const Expr *origFormatExpr, unsigned firstDataArg, 2846 unsigned numDataArgs, const char *beg, bool hasVAListArg, 2847 Expr **Args, unsigned NumArgs, 2848 unsigned formatIdx, bool inFunctionCall, 2849 Sema::VariadicCallType CallType) 2850 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 2851 numDataArgs, beg, hasVAListArg, 2852 Args, NumArgs, formatIdx, inFunctionCall, CallType) 2853 {} 2854 2855 bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS, 2856 const char *startSpecifier, 2857 unsigned specifierLen); 2858 2859 bool HandleInvalidScanfConversionSpecifier( 2860 const analyze_scanf::ScanfSpecifier &FS, 2861 const char *startSpecifier, 2862 unsigned specifierLen); 2863 2864 void HandleIncompleteScanList(const char *start, const char *end); 2865}; 2866} 2867 2868void CheckScanfHandler::HandleIncompleteScanList(const char *start, 2869 const char *end) { 2870 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete), 2871 getLocationOfByte(end), /*IsStringLocation*/true, 2872 getSpecifierRange(start, end - start)); 2873} 2874 2875bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier( 2876 const analyze_scanf::ScanfSpecifier &FS, 2877 const char *startSpecifier, 2878 unsigned specifierLen) { 2879 2880 const analyze_scanf::ScanfConversionSpecifier &CS = 2881 FS.getConversionSpecifier(); 2882 2883 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 2884 getLocationOfByte(CS.getStart()), 2885 startSpecifier, specifierLen, 2886 CS.getStart(), CS.getLength()); 2887} 2888 2889bool CheckScanfHandler::HandleScanfSpecifier( 2890 const analyze_scanf::ScanfSpecifier &FS, 2891 const char *startSpecifier, 2892 unsigned specifierLen) { 2893 2894 using namespace analyze_scanf; 2895 using namespace analyze_format_string; 2896 2897 const ScanfConversionSpecifier &CS = FS.getConversionSpecifier(); 2898 2899 // Handle case where '%' and '*' don't consume an argument. These shouldn't 2900 // be used to decide if we are using positional arguments consistently. 2901 if (FS.consumesDataArgument()) { 2902 if (atFirstArg) { 2903 atFirstArg = false; 2904 usesPositionalArgs = FS.usesPositionalArg(); 2905 } 2906 else if (usesPositionalArgs != FS.usesPositionalArg()) { 2907 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 2908 startSpecifier, specifierLen); 2909 return false; 2910 } 2911 } 2912 2913 // Check if the field with is non-zero. 2914 const OptionalAmount &Amt = FS.getFieldWidth(); 2915 if (Amt.getHowSpecified() == OptionalAmount::Constant) { 2916 if (Amt.getConstantAmount() == 0) { 2917 const CharSourceRange &R = getSpecifierRange(Amt.getStart(), 2918 Amt.getConstantLength()); 2919 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width), 2920 getLocationOfByte(Amt.getStart()), 2921 /*IsStringLocation*/true, R, 2922 FixItHint::CreateRemoval(R)); 2923 } 2924 } 2925 2926 if (!FS.consumesDataArgument()) { 2927 // FIXME: Technically specifying a precision or field width here 2928 // makes no sense. Worth issuing a warning at some point. 2929 return true; 2930 } 2931 2932 // Consume the argument. 2933 unsigned argIndex = FS.getArgIndex(); 2934 if (argIndex < NumDataArgs) { 2935 // The check to see if the argIndex is valid will come later. 2936 // We set the bit here because we may exit early from this 2937 // function if we encounter some other error. 2938 CoveredArgs.set(argIndex); 2939 } 2940 2941 // Check the length modifier is valid with the given conversion specifier. 2942 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 2943 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 2944 diag::warn_format_nonsensical_length); 2945 else if (!FS.hasStandardLengthModifier()) 2946 HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen); 2947 else if (!FS.hasStandardLengthConversionCombination()) 2948 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 2949 diag::warn_format_non_standard_conversion_spec); 2950 2951 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 2952 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 2953 2954 // The remaining checks depend on the data arguments. 2955 if (HasVAListArg) 2956 return true; 2957 2958 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 2959 return false; 2960 2961 // Check that the argument type matches the format specifier. 2962 const Expr *Ex = getDataArg(argIndex); 2963 if (!Ex) 2964 return true; 2965 2966 const analyze_format_string::ArgType &AT = FS.getArgType(S.Context); 2967 if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType())) { 2968 ScanfSpecifier fixedFS = FS; 2969 bool success = fixedFS.fixType(Ex->getType(), S.getLangOpts(), 2970 S.Context); 2971 2972 if (success) { 2973 // Get the fix string from the fixed format specifier. 2974 SmallString<128> buf; 2975 llvm::raw_svector_ostream os(buf); 2976 fixedFS.toString(os); 2977 2978 EmitFormatDiagnostic( 2979 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2980 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() 2981 << Ex->getSourceRange(), 2982 Ex->getLocStart(), 2983 /*IsStringLocation*/false, 2984 getSpecifierRange(startSpecifier, specifierLen), 2985 FixItHint::CreateReplacement( 2986 getSpecifierRange(startSpecifier, specifierLen), 2987 os.str())); 2988 } else { 2989 EmitFormatDiagnostic( 2990 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2991 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() 2992 << Ex->getSourceRange(), 2993 Ex->getLocStart(), 2994 /*IsStringLocation*/false, 2995 getSpecifierRange(startSpecifier, specifierLen)); 2996 } 2997 } 2998 2999 return true; 3000} 3001 3002void Sema::CheckFormatString(const StringLiteral *FExpr, 3003 const Expr *OrigFormatExpr, 3004 Expr **Args, unsigned NumArgs, 3005 bool HasVAListArg, unsigned format_idx, 3006 unsigned firstDataArg, FormatStringType Type, 3007 bool inFunctionCall, VariadicCallType CallType) { 3008 3009 // CHECK: is the format string a wide literal? 3010 if (!FExpr->isAscii() && !FExpr->isUTF8()) { 3011 CheckFormatHandler::EmitFormatDiagnostic( 3012 *this, inFunctionCall, Args[format_idx], 3013 PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(), 3014 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 3015 return; 3016 } 3017 3018 // Str - The format string. NOTE: this is NOT null-terminated! 3019 StringRef StrRef = FExpr->getString(); 3020 const char *Str = StrRef.data(); 3021 unsigned StrLen = StrRef.size(); 3022 const unsigned numDataArgs = NumArgs - firstDataArg; 3023 3024 // CHECK: empty format string? 3025 if (StrLen == 0 && numDataArgs > 0) { 3026 CheckFormatHandler::EmitFormatDiagnostic( 3027 *this, inFunctionCall, Args[format_idx], 3028 PDiag(diag::warn_empty_format_string), FExpr->getLocStart(), 3029 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 3030 return; 3031 } 3032 3033 if (Type == FST_Printf || Type == FST_NSString) { 3034 CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 3035 numDataArgs, (Type == FST_NSString), 3036 Str, HasVAListArg, Args, NumArgs, format_idx, 3037 inFunctionCall, CallType); 3038 3039 if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen, 3040 getLangOpts(), 3041 Context.getTargetInfo())) 3042 H.DoneProcessing(); 3043 } else if (Type == FST_Scanf) { 3044 CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, numDataArgs, 3045 Str, HasVAListArg, Args, NumArgs, format_idx, 3046 inFunctionCall, CallType); 3047 3048 if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen, 3049 getLangOpts(), 3050 Context.getTargetInfo())) 3051 H.DoneProcessing(); 3052 } // TODO: handle other formats 3053} 3054 3055//===--- CHECK: Standard memory functions ---------------------------------===// 3056 3057/// \brief Determine whether the given type is a dynamic class type (e.g., 3058/// whether it has a vtable). 3059static bool isDynamicClassType(QualType T) { 3060 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) 3061 if (CXXRecordDecl *Definition = Record->getDefinition()) 3062 if (Definition->isDynamicClass()) 3063 return true; 3064 3065 return false; 3066} 3067 3068/// \brief If E is a sizeof expression, returns its argument expression, 3069/// otherwise returns NULL. 3070static const Expr *getSizeOfExprArg(const Expr* E) { 3071 if (const UnaryExprOrTypeTraitExpr *SizeOf = 3072 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 3073 if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType()) 3074 return SizeOf->getArgumentExpr()->IgnoreParenImpCasts(); 3075 3076 return 0; 3077} 3078 3079/// \brief If E is a sizeof expression, returns its argument type. 3080static QualType getSizeOfArgType(const Expr* E) { 3081 if (const UnaryExprOrTypeTraitExpr *SizeOf = 3082 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 3083 if (SizeOf->getKind() == clang::UETT_SizeOf) 3084 return SizeOf->getTypeOfArgument(); 3085 3086 return QualType(); 3087} 3088 3089/// \brief Check for dangerous or invalid arguments to memset(). 3090/// 3091/// This issues warnings on known problematic, dangerous or unspecified 3092/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp' 3093/// function calls. 3094/// 3095/// \param Call The call expression to diagnose. 3096void Sema::CheckMemaccessArguments(const CallExpr *Call, 3097 unsigned BId, 3098 IdentifierInfo *FnName) { 3099 assert(BId != 0); 3100 3101 // It is possible to have a non-standard definition of memset. Validate 3102 // we have enough arguments, and if not, abort further checking. 3103 unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3); 3104 if (Call->getNumArgs() < ExpectedNumArgs) 3105 return; 3106 3107 unsigned LastArg = (BId == Builtin::BImemset || 3108 BId == Builtin::BIstrndup ? 1 : 2); 3109 unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2); 3110 const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts(); 3111 3112 // We have special checking when the length is a sizeof expression. 3113 QualType SizeOfArgTy = getSizeOfArgType(LenExpr); 3114 const Expr *SizeOfArg = getSizeOfExprArg(LenExpr); 3115 llvm::FoldingSetNodeID SizeOfArgID; 3116 3117 for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) { 3118 const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts(); 3119 SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange(); 3120 3121 QualType DestTy = Dest->getType(); 3122 if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) { 3123 QualType PointeeTy = DestPtrTy->getPointeeType(); 3124 3125 // Never warn about void type pointers. This can be used to suppress 3126 // false positives. 3127 if (PointeeTy->isVoidType()) 3128 continue; 3129 3130 // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by 3131 // actually comparing the expressions for equality. Because computing the 3132 // expression IDs can be expensive, we only do this if the diagnostic is 3133 // enabled. 3134 if (SizeOfArg && 3135 Diags.getDiagnosticLevel(diag::warn_sizeof_pointer_expr_memaccess, 3136 SizeOfArg->getExprLoc())) { 3137 // We only compute IDs for expressions if the warning is enabled, and 3138 // cache the sizeof arg's ID. 3139 if (SizeOfArgID == llvm::FoldingSetNodeID()) 3140 SizeOfArg->Profile(SizeOfArgID, Context, true); 3141 llvm::FoldingSetNodeID DestID; 3142 Dest->Profile(DestID, Context, true); 3143 if (DestID == SizeOfArgID) { 3144 // TODO: For strncpy() and friends, this could suggest sizeof(dst) 3145 // over sizeof(src) as well. 3146 unsigned ActionIdx = 0; // Default is to suggest dereferencing. 3147 StringRef ReadableName = FnName->getName(); 3148 3149 if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest)) 3150 if (UnaryOp->getOpcode() == UO_AddrOf) 3151 ActionIdx = 1; // If its an address-of operator, just remove it. 3152 if (Context.getTypeSize(PointeeTy) == Context.getCharWidth()) 3153 ActionIdx = 2; // If the pointee's size is sizeof(char), 3154 // suggest an explicit length. 3155 3156 // If the function is defined as a builtin macro, do not show macro 3157 // expansion. 3158 SourceLocation SL = SizeOfArg->getExprLoc(); 3159 SourceRange DSR = Dest->getSourceRange(); 3160 SourceRange SSR = SizeOfArg->getSourceRange(); 3161 SourceManager &SM = PP.getSourceManager(); 3162 3163 if (SM.isMacroArgExpansion(SL)) { 3164 ReadableName = Lexer::getImmediateMacroName(SL, SM, LangOpts); 3165 SL = SM.getSpellingLoc(SL); 3166 DSR = SourceRange(SM.getSpellingLoc(DSR.getBegin()), 3167 SM.getSpellingLoc(DSR.getEnd())); 3168 SSR = SourceRange(SM.getSpellingLoc(SSR.getBegin()), 3169 SM.getSpellingLoc(SSR.getEnd())); 3170 } 3171 3172 DiagRuntimeBehavior(SL, SizeOfArg, 3173 PDiag(diag::warn_sizeof_pointer_expr_memaccess) 3174 << ReadableName 3175 << PointeeTy 3176 << DestTy 3177 << DSR 3178 << SSR); 3179 DiagRuntimeBehavior(SL, SizeOfArg, 3180 PDiag(diag::warn_sizeof_pointer_expr_memaccess_note) 3181 << ActionIdx 3182 << SSR); 3183 3184 break; 3185 } 3186 } 3187 3188 // Also check for cases where the sizeof argument is the exact same 3189 // type as the memory argument, and where it points to a user-defined 3190 // record type. 3191 if (SizeOfArgTy != QualType()) { 3192 if (PointeeTy->isRecordType() && 3193 Context.typesAreCompatible(SizeOfArgTy, DestTy)) { 3194 DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest, 3195 PDiag(diag::warn_sizeof_pointer_type_memaccess) 3196 << FnName << SizeOfArgTy << ArgIdx 3197 << PointeeTy << Dest->getSourceRange() 3198 << LenExpr->getSourceRange()); 3199 break; 3200 } 3201 } 3202 3203 // Always complain about dynamic classes. 3204 if (isDynamicClassType(PointeeTy)) { 3205 3206 unsigned OperationType = 0; 3207 // "overwritten" if we're warning about the destination for any call 3208 // but memcmp; otherwise a verb appropriate to the call. 3209 if (ArgIdx != 0 || BId == Builtin::BImemcmp) { 3210 if (BId == Builtin::BImemcpy) 3211 OperationType = 1; 3212 else if(BId == Builtin::BImemmove) 3213 OperationType = 2; 3214 else if (BId == Builtin::BImemcmp) 3215 OperationType = 3; 3216 } 3217 3218 DiagRuntimeBehavior( 3219 Dest->getExprLoc(), Dest, 3220 PDiag(diag::warn_dyn_class_memaccess) 3221 << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx) 3222 << FnName << PointeeTy 3223 << OperationType 3224 << Call->getCallee()->getSourceRange()); 3225 } else if (PointeeTy.hasNonTrivialObjCLifetime() && 3226 BId != Builtin::BImemset) 3227 DiagRuntimeBehavior( 3228 Dest->getExprLoc(), Dest, 3229 PDiag(diag::warn_arc_object_memaccess) 3230 << ArgIdx << FnName << PointeeTy 3231 << Call->getCallee()->getSourceRange()); 3232 else 3233 continue; 3234 3235 DiagRuntimeBehavior( 3236 Dest->getExprLoc(), Dest, 3237 PDiag(diag::note_bad_memaccess_silence) 3238 << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)")); 3239 break; 3240 } 3241 } 3242} 3243 3244// A little helper routine: ignore addition and subtraction of integer literals. 3245// This intentionally does not ignore all integer constant expressions because 3246// we don't want to remove sizeof(). 3247static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) { 3248 Ex = Ex->IgnoreParenCasts(); 3249 3250 for (;;) { 3251 const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex); 3252 if (!BO || !BO->isAdditiveOp()) 3253 break; 3254 3255 const Expr *RHS = BO->getRHS()->IgnoreParenCasts(); 3256 const Expr *LHS = BO->getLHS()->IgnoreParenCasts(); 3257 3258 if (isa<IntegerLiteral>(RHS)) 3259 Ex = LHS; 3260 else if (isa<IntegerLiteral>(LHS)) 3261 Ex = RHS; 3262 else 3263 break; 3264 } 3265 3266 return Ex; 3267} 3268 3269static bool isConstantSizeArrayWithMoreThanOneElement(QualType Ty, 3270 ASTContext &Context) { 3271 // Only handle constant-sized or VLAs, but not flexible members. 3272 if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(Ty)) { 3273 // Only issue the FIXIT for arrays of size > 1. 3274 if (CAT->getSize().getSExtValue() <= 1) 3275 return false; 3276 } else if (!Ty->isVariableArrayType()) { 3277 return false; 3278 } 3279 return true; 3280} 3281 3282// Warn if the user has made the 'size' argument to strlcpy or strlcat 3283// be the size of the source, instead of the destination. 3284void Sema::CheckStrlcpycatArguments(const CallExpr *Call, 3285 IdentifierInfo *FnName) { 3286 3287 // Don't crash if the user has the wrong number of arguments 3288 if (Call->getNumArgs() != 3) 3289 return; 3290 3291 const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context); 3292 const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context); 3293 const Expr *CompareWithSrc = NULL; 3294 3295 // Look for 'strlcpy(dst, x, sizeof(x))' 3296 if (const Expr *Ex = getSizeOfExprArg(SizeArg)) 3297 CompareWithSrc = Ex; 3298 else { 3299 // Look for 'strlcpy(dst, x, strlen(x))' 3300 if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) { 3301 if (SizeCall->isBuiltinCall() == Builtin::BIstrlen 3302 && SizeCall->getNumArgs() == 1) 3303 CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context); 3304 } 3305 } 3306 3307 if (!CompareWithSrc) 3308 return; 3309 3310 // Determine if the argument to sizeof/strlen is equal to the source 3311 // argument. In principle there's all kinds of things you could do 3312 // here, for instance creating an == expression and evaluating it with 3313 // EvaluateAsBooleanCondition, but this uses a more direct technique: 3314 const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg); 3315 if (!SrcArgDRE) 3316 return; 3317 3318 const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc); 3319 if (!CompareWithSrcDRE || 3320 SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl()) 3321 return; 3322 3323 const Expr *OriginalSizeArg = Call->getArg(2); 3324 Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size) 3325 << OriginalSizeArg->getSourceRange() << FnName; 3326 3327 // Output a FIXIT hint if the destination is an array (rather than a 3328 // pointer to an array). This could be enhanced to handle some 3329 // pointers if we know the actual size, like if DstArg is 'array+2' 3330 // we could say 'sizeof(array)-2'. 3331 const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts(); 3332 if (!isConstantSizeArrayWithMoreThanOneElement(DstArg->getType(), Context)) 3333 return; 3334 3335 SmallString<128> sizeString; 3336 llvm::raw_svector_ostream OS(sizeString); 3337 OS << "sizeof("; 3338 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3339 OS << ")"; 3340 3341 Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size) 3342 << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(), 3343 OS.str()); 3344} 3345 3346/// Check if two expressions refer to the same declaration. 3347static bool referToTheSameDecl(const Expr *E1, const Expr *E2) { 3348 if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1)) 3349 if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2)) 3350 return D1->getDecl() == D2->getDecl(); 3351 return false; 3352} 3353 3354static const Expr *getStrlenExprArg(const Expr *E) { 3355 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 3356 const FunctionDecl *FD = CE->getDirectCallee(); 3357 if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen) 3358 return 0; 3359 return CE->getArg(0)->IgnoreParenCasts(); 3360 } 3361 return 0; 3362} 3363 3364// Warn on anti-patterns as the 'size' argument to strncat. 3365// The correct size argument should look like following: 3366// strncat(dst, src, sizeof(dst) - strlen(dest) - 1); 3367void Sema::CheckStrncatArguments(const CallExpr *CE, 3368 IdentifierInfo *FnName) { 3369 // Don't crash if the user has the wrong number of arguments. 3370 if (CE->getNumArgs() < 3) 3371 return; 3372 const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts(); 3373 const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts(); 3374 const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts(); 3375 3376 // Identify common expressions, which are wrongly used as the size argument 3377 // to strncat and may lead to buffer overflows. 3378 unsigned PatternType = 0; 3379 if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) { 3380 // - sizeof(dst) 3381 if (referToTheSameDecl(SizeOfArg, DstArg)) 3382 PatternType = 1; 3383 // - sizeof(src) 3384 else if (referToTheSameDecl(SizeOfArg, SrcArg)) 3385 PatternType = 2; 3386 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) { 3387 if (BE->getOpcode() == BO_Sub) { 3388 const Expr *L = BE->getLHS()->IgnoreParenCasts(); 3389 const Expr *R = BE->getRHS()->IgnoreParenCasts(); 3390 // - sizeof(dst) - strlen(dst) 3391 if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) && 3392 referToTheSameDecl(DstArg, getStrlenExprArg(R))) 3393 PatternType = 1; 3394 // - sizeof(src) - (anything) 3395 else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L))) 3396 PatternType = 2; 3397 } 3398 } 3399 3400 if (PatternType == 0) 3401 return; 3402 3403 // Generate the diagnostic. 3404 SourceLocation SL = LenArg->getLocStart(); 3405 SourceRange SR = LenArg->getSourceRange(); 3406 SourceManager &SM = PP.getSourceManager(); 3407 3408 // If the function is defined as a builtin macro, do not show macro expansion. 3409 if (SM.isMacroArgExpansion(SL)) { 3410 SL = SM.getSpellingLoc(SL); 3411 SR = SourceRange(SM.getSpellingLoc(SR.getBegin()), 3412 SM.getSpellingLoc(SR.getEnd())); 3413 } 3414 3415 // Check if the destination is an array (rather than a pointer to an array). 3416 QualType DstTy = DstArg->getType(); 3417 bool isKnownSizeArray = isConstantSizeArrayWithMoreThanOneElement(DstTy, 3418 Context); 3419 if (!isKnownSizeArray) { 3420 if (PatternType == 1) 3421 Diag(SL, diag::warn_strncat_wrong_size) << SR; 3422 else 3423 Diag(SL, diag::warn_strncat_src_size) << SR; 3424 return; 3425 } 3426 3427 if (PatternType == 1) 3428 Diag(SL, diag::warn_strncat_large_size) << SR; 3429 else 3430 Diag(SL, diag::warn_strncat_src_size) << SR; 3431 3432 SmallString<128> sizeString; 3433 llvm::raw_svector_ostream OS(sizeString); 3434 OS << "sizeof("; 3435 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3436 OS << ") - "; 3437 OS << "strlen("; 3438 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3439 OS << ") - 1"; 3440 3441 Diag(SL, diag::note_strncat_wrong_size) 3442 << FixItHint::CreateReplacement(SR, OS.str()); 3443} 3444 3445//===--- CHECK: Return Address of Stack Variable --------------------------===// 3446 3447static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3448 Decl *ParentDecl); 3449static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars, 3450 Decl *ParentDecl); 3451 3452/// CheckReturnStackAddr - Check if a return statement returns the address 3453/// of a stack variable. 3454void 3455Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType, 3456 SourceLocation ReturnLoc) { 3457 3458 Expr *stackE = 0; 3459 SmallVector<DeclRefExpr *, 8> refVars; 3460 3461 // Perform checking for returned stack addresses, local blocks, 3462 // label addresses or references to temporaries. 3463 if (lhsType->isPointerType() || 3464 (!getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) { 3465 stackE = EvalAddr(RetValExp, refVars, /*ParentDecl=*/0); 3466 } else if (lhsType->isReferenceType()) { 3467 stackE = EvalVal(RetValExp, refVars, /*ParentDecl=*/0); 3468 } 3469 3470 if (stackE == 0) 3471 return; // Nothing suspicious was found. 3472 3473 SourceLocation diagLoc; 3474 SourceRange diagRange; 3475 if (refVars.empty()) { 3476 diagLoc = stackE->getLocStart(); 3477 diagRange = stackE->getSourceRange(); 3478 } else { 3479 // We followed through a reference variable. 'stackE' contains the 3480 // problematic expression but we will warn at the return statement pointing 3481 // at the reference variable. We will later display the "trail" of 3482 // reference variables using notes. 3483 diagLoc = refVars[0]->getLocStart(); 3484 diagRange = refVars[0]->getSourceRange(); 3485 } 3486 3487 if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var. 3488 Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref 3489 : diag::warn_ret_stack_addr) 3490 << DR->getDecl()->getDeclName() << diagRange; 3491 } else if (isa<BlockExpr>(stackE)) { // local block. 3492 Diag(diagLoc, diag::err_ret_local_block) << diagRange; 3493 } else if (isa<AddrLabelExpr>(stackE)) { // address of label. 3494 Diag(diagLoc, diag::warn_ret_addr_label) << diagRange; 3495 } else { // local temporary. 3496 Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref 3497 : diag::warn_ret_local_temp_addr) 3498 << diagRange; 3499 } 3500 3501 // Display the "trail" of reference variables that we followed until we 3502 // found the problematic expression using notes. 3503 for (unsigned i = 0, e = refVars.size(); i != e; ++i) { 3504 VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl()); 3505 // If this var binds to another reference var, show the range of the next 3506 // var, otherwise the var binds to the problematic expression, in which case 3507 // show the range of the expression. 3508 SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange() 3509 : stackE->getSourceRange(); 3510 Diag(VD->getLocation(), diag::note_ref_var_local_bind) 3511 << VD->getDeclName() << range; 3512 } 3513} 3514 3515/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that 3516/// check if the expression in a return statement evaluates to an address 3517/// to a location on the stack, a local block, an address of a label, or a 3518/// reference to local temporary. The recursion is used to traverse the 3519/// AST of the return expression, with recursion backtracking when we 3520/// encounter a subexpression that (1) clearly does not lead to one of the 3521/// above problematic expressions (2) is something we cannot determine leads to 3522/// a problematic expression based on such local checking. 3523/// 3524/// Both EvalAddr and EvalVal follow through reference variables to evaluate 3525/// the expression that they point to. Such variables are added to the 3526/// 'refVars' vector so that we know what the reference variable "trail" was. 3527/// 3528/// EvalAddr processes expressions that are pointers that are used as 3529/// references (and not L-values). EvalVal handles all other values. 3530/// At the base case of the recursion is a check for the above problematic 3531/// expressions. 3532/// 3533/// This implementation handles: 3534/// 3535/// * pointer-to-pointer casts 3536/// * implicit conversions from array references to pointers 3537/// * taking the address of fields 3538/// * arbitrary interplay between "&" and "*" operators 3539/// * pointer arithmetic from an address of a stack variable 3540/// * taking the address of an array element where the array is on the stack 3541static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3542 Decl *ParentDecl) { 3543 if (E->isTypeDependent()) 3544 return NULL; 3545 3546 // We should only be called for evaluating pointer expressions. 3547 assert((E->getType()->isAnyPointerType() || 3548 E->getType()->isBlockPointerType() || 3549 E->getType()->isObjCQualifiedIdType()) && 3550 "EvalAddr only works on pointers"); 3551 3552 E = E->IgnoreParens(); 3553 3554 // Our "symbolic interpreter" is just a dispatch off the currently 3555 // viewed AST node. We then recursively traverse the AST by calling 3556 // EvalAddr and EvalVal appropriately. 3557 switch (E->getStmtClass()) { 3558 case Stmt::DeclRefExprClass: { 3559 DeclRefExpr *DR = cast<DeclRefExpr>(E); 3560 3561 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) 3562 // If this is a reference variable, follow through to the expression that 3563 // it points to. 3564 if (V->hasLocalStorage() && 3565 V->getType()->isReferenceType() && V->hasInit()) { 3566 // Add the reference variable to the "trail". 3567 refVars.push_back(DR); 3568 return EvalAddr(V->getInit(), refVars, ParentDecl); 3569 } 3570 3571 return NULL; 3572 } 3573 3574 case Stmt::UnaryOperatorClass: { 3575 // The only unary operator that make sense to handle here 3576 // is AddrOf. All others don't make sense as pointers. 3577 UnaryOperator *U = cast<UnaryOperator>(E); 3578 3579 if (U->getOpcode() == UO_AddrOf) 3580 return EvalVal(U->getSubExpr(), refVars, ParentDecl); 3581 else 3582 return NULL; 3583 } 3584 3585 case Stmt::BinaryOperatorClass: { 3586 // Handle pointer arithmetic. All other binary operators are not valid 3587 // in this context. 3588 BinaryOperator *B = cast<BinaryOperator>(E); 3589 BinaryOperatorKind op = B->getOpcode(); 3590 3591 if (op != BO_Add && op != BO_Sub) 3592 return NULL; 3593 3594 Expr *Base = B->getLHS(); 3595 3596 // Determine which argument is the real pointer base. It could be 3597 // the RHS argument instead of the LHS. 3598 if (!Base->getType()->isPointerType()) Base = B->getRHS(); 3599 3600 assert (Base->getType()->isPointerType()); 3601 return EvalAddr(Base, refVars, ParentDecl); 3602 } 3603 3604 // For conditional operators we need to see if either the LHS or RHS are 3605 // valid DeclRefExpr*s. If one of them is valid, we return it. 3606 case Stmt::ConditionalOperatorClass: { 3607 ConditionalOperator *C = cast<ConditionalOperator>(E); 3608 3609 // Handle the GNU extension for missing LHS. 3610 if (Expr *lhsExpr = C->getLHS()) { 3611 // In C++, we can have a throw-expression, which has 'void' type. 3612 if (!lhsExpr->getType()->isVoidType()) 3613 if (Expr* LHS = EvalAddr(lhsExpr, refVars, ParentDecl)) 3614 return LHS; 3615 } 3616 3617 // In C++, we can have a throw-expression, which has 'void' type. 3618 if (C->getRHS()->getType()->isVoidType()) 3619 return NULL; 3620 3621 return EvalAddr(C->getRHS(), refVars, ParentDecl); 3622 } 3623 3624 case Stmt::BlockExprClass: 3625 if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures()) 3626 return E; // local block. 3627 return NULL; 3628 3629 case Stmt::AddrLabelExprClass: 3630 return E; // address of label. 3631 3632 case Stmt::ExprWithCleanupsClass: 3633 return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars, 3634 ParentDecl); 3635 3636 // For casts, we need to handle conversions from arrays to 3637 // pointer values, and pointer-to-pointer conversions. 3638 case Stmt::ImplicitCastExprClass: 3639 case Stmt::CStyleCastExprClass: 3640 case Stmt::CXXFunctionalCastExprClass: 3641 case Stmt::ObjCBridgedCastExprClass: 3642 case Stmt::CXXStaticCastExprClass: 3643 case Stmt::CXXDynamicCastExprClass: 3644 case Stmt::CXXConstCastExprClass: 3645 case Stmt::CXXReinterpretCastExprClass: { 3646 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr(); 3647 switch (cast<CastExpr>(E)->getCastKind()) { 3648 case CK_BitCast: 3649 case CK_LValueToRValue: 3650 case CK_NoOp: 3651 case CK_BaseToDerived: 3652 case CK_DerivedToBase: 3653 case CK_UncheckedDerivedToBase: 3654 case CK_Dynamic: 3655 case CK_CPointerToObjCPointerCast: 3656 case CK_BlockPointerToObjCPointerCast: 3657 case CK_AnyPointerToBlockPointerCast: 3658 return EvalAddr(SubExpr, refVars, ParentDecl); 3659 3660 case CK_ArrayToPointerDecay: 3661 return EvalVal(SubExpr, refVars, ParentDecl); 3662 3663 default: 3664 return 0; 3665 } 3666 } 3667 3668 case Stmt::MaterializeTemporaryExprClass: 3669 if (Expr *Result = EvalAddr( 3670 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 3671 refVars, ParentDecl)) 3672 return Result; 3673 3674 return E; 3675 3676 // Everything else: we simply don't reason about them. 3677 default: 3678 return NULL; 3679 } 3680} 3681 3682 3683/// EvalVal - This function is complements EvalAddr in the mutual recursion. 3684/// See the comments for EvalAddr for more details. 3685static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3686 Decl *ParentDecl) { 3687do { 3688 // We should only be called for evaluating non-pointer expressions, or 3689 // expressions with a pointer type that are not used as references but instead 3690 // are l-values (e.g., DeclRefExpr with a pointer type). 3691 3692 // Our "symbolic interpreter" is just a dispatch off the currently 3693 // viewed AST node. We then recursively traverse the AST by calling 3694 // EvalAddr and EvalVal appropriately. 3695 3696 E = E->IgnoreParens(); 3697 switch (E->getStmtClass()) { 3698 case Stmt::ImplicitCastExprClass: { 3699 ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E); 3700 if (IE->getValueKind() == VK_LValue) { 3701 E = IE->getSubExpr(); 3702 continue; 3703 } 3704 return NULL; 3705 } 3706 3707 case Stmt::ExprWithCleanupsClass: 3708 return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,ParentDecl); 3709 3710 case Stmt::DeclRefExprClass: { 3711 // When we hit a DeclRefExpr we are looking at code that refers to a 3712 // variable's name. If it's not a reference variable we check if it has 3713 // local storage within the function, and if so, return the expression. 3714 DeclRefExpr *DR = cast<DeclRefExpr>(E); 3715 3716 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) { 3717 // Check if it refers to itself, e.g. "int& i = i;". 3718 if (V == ParentDecl) 3719 return DR; 3720 3721 if (V->hasLocalStorage()) { 3722 if (!V->getType()->isReferenceType()) 3723 return DR; 3724 3725 // Reference variable, follow through to the expression that 3726 // it points to. 3727 if (V->hasInit()) { 3728 // Add the reference variable to the "trail". 3729 refVars.push_back(DR); 3730 return EvalVal(V->getInit(), refVars, V); 3731 } 3732 } 3733 } 3734 3735 return NULL; 3736 } 3737 3738 case Stmt::UnaryOperatorClass: { 3739 // The only unary operator that make sense to handle here 3740 // is Deref. All others don't resolve to a "name." This includes 3741 // handling all sorts of rvalues passed to a unary operator. 3742 UnaryOperator *U = cast<UnaryOperator>(E); 3743 3744 if (U->getOpcode() == UO_Deref) 3745 return EvalAddr(U->getSubExpr(), refVars, ParentDecl); 3746 3747 return NULL; 3748 } 3749 3750 case Stmt::ArraySubscriptExprClass: { 3751 // Array subscripts are potential references to data on the stack. We 3752 // retrieve the DeclRefExpr* for the array variable if it indeed 3753 // has local storage. 3754 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars,ParentDecl); 3755 } 3756 3757 case Stmt::ConditionalOperatorClass: { 3758 // For conditional operators we need to see if either the LHS or RHS are 3759 // non-NULL Expr's. If one is non-NULL, we return it. 3760 ConditionalOperator *C = cast<ConditionalOperator>(E); 3761 3762 // Handle the GNU extension for missing LHS. 3763 if (Expr *lhsExpr = C->getLHS()) 3764 if (Expr *LHS = EvalVal(lhsExpr, refVars, ParentDecl)) 3765 return LHS; 3766 3767 return EvalVal(C->getRHS(), refVars, ParentDecl); 3768 } 3769 3770 // Accesses to members are potential references to data on the stack. 3771 case Stmt::MemberExprClass: { 3772 MemberExpr *M = cast<MemberExpr>(E); 3773 3774 // Check for indirect access. We only want direct field accesses. 3775 if (M->isArrow()) 3776 return NULL; 3777 3778 // Check whether the member type is itself a reference, in which case 3779 // we're not going to refer to the member, but to what the member refers to. 3780 if (M->getMemberDecl()->getType()->isReferenceType()) 3781 return NULL; 3782 3783 return EvalVal(M->getBase(), refVars, ParentDecl); 3784 } 3785 3786 case Stmt::MaterializeTemporaryExprClass: 3787 if (Expr *Result = EvalVal( 3788 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 3789 refVars, ParentDecl)) 3790 return Result; 3791 3792 return E; 3793 3794 default: 3795 // Check that we don't return or take the address of a reference to a 3796 // temporary. This is only useful in C++. 3797 if (!E->isTypeDependent() && E->isRValue()) 3798 return E; 3799 3800 // Everything else: we simply don't reason about them. 3801 return NULL; 3802 } 3803} while (true); 3804} 3805 3806//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===// 3807 3808/// Check for comparisons of floating point operands using != and ==. 3809/// Issue a warning if these are no self-comparisons, as they are not likely 3810/// to do what the programmer intended. 3811void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) { 3812 Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts(); 3813 Expr* RightExprSansParen = RHS->IgnoreParenImpCasts(); 3814 3815 // Special case: check for x == x (which is OK). 3816 // Do not emit warnings for such cases. 3817 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen)) 3818 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen)) 3819 if (DRL->getDecl() == DRR->getDecl()) 3820 return; 3821 3822 3823 // Special case: check for comparisons against literals that can be exactly 3824 // represented by APFloat. In such cases, do not emit a warning. This 3825 // is a heuristic: often comparison against such literals are used to 3826 // detect if a value in a variable has not changed. This clearly can 3827 // lead to false negatives. 3828 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) { 3829 if (FLL->isExact()) 3830 return; 3831 } else 3832 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)) 3833 if (FLR->isExact()) 3834 return; 3835 3836 // Check for comparisons with builtin types. 3837 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen)) 3838 if (CL->isBuiltinCall()) 3839 return; 3840 3841 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen)) 3842 if (CR->isBuiltinCall()) 3843 return; 3844 3845 // Emit the diagnostic. 3846 Diag(Loc, diag::warn_floatingpoint_eq) 3847 << LHS->getSourceRange() << RHS->getSourceRange(); 3848} 3849 3850//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===// 3851//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===// 3852 3853namespace { 3854 3855/// Structure recording the 'active' range of an integer-valued 3856/// expression. 3857struct IntRange { 3858 /// The number of bits active in the int. 3859 unsigned Width; 3860 3861 /// True if the int is known not to have negative values. 3862 bool NonNegative; 3863 3864 IntRange(unsigned Width, bool NonNegative) 3865 : Width(Width), NonNegative(NonNegative) 3866 {} 3867 3868 /// Returns the range of the bool type. 3869 static IntRange forBoolType() { 3870 return IntRange(1, true); 3871 } 3872 3873 /// Returns the range of an opaque value of the given integral type. 3874 static IntRange forValueOfType(ASTContext &C, QualType T) { 3875 return forValueOfCanonicalType(C, 3876 T->getCanonicalTypeInternal().getTypePtr()); 3877 } 3878 3879 /// Returns the range of an opaque value of a canonical integral type. 3880 static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) { 3881 assert(T->isCanonicalUnqualified()); 3882 3883 if (const VectorType *VT = dyn_cast<VectorType>(T)) 3884 T = VT->getElementType().getTypePtr(); 3885 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 3886 T = CT->getElementType().getTypePtr(); 3887 3888 // For enum types, use the known bit width of the enumerators. 3889 if (const EnumType *ET = dyn_cast<EnumType>(T)) { 3890 EnumDecl *Enum = ET->getDecl(); 3891 if (!Enum->isCompleteDefinition()) 3892 return IntRange(C.getIntWidth(QualType(T, 0)), false); 3893 3894 unsigned NumPositive = Enum->getNumPositiveBits(); 3895 unsigned NumNegative = Enum->getNumNegativeBits(); 3896 3897 return IntRange(std::max(NumPositive, NumNegative), NumNegative == 0); 3898 } 3899 3900 const BuiltinType *BT = cast<BuiltinType>(T); 3901 assert(BT->isInteger()); 3902 3903 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 3904 } 3905 3906 /// Returns the "target" range of a canonical integral type, i.e. 3907 /// the range of values expressible in the type. 3908 /// 3909 /// This matches forValueOfCanonicalType except that enums have the 3910 /// full range of their type, not the range of their enumerators. 3911 static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) { 3912 assert(T->isCanonicalUnqualified()); 3913 3914 if (const VectorType *VT = dyn_cast<VectorType>(T)) 3915 T = VT->getElementType().getTypePtr(); 3916 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 3917 T = CT->getElementType().getTypePtr(); 3918 if (const EnumType *ET = dyn_cast<EnumType>(T)) 3919 T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr(); 3920 3921 const BuiltinType *BT = cast<BuiltinType>(T); 3922 assert(BT->isInteger()); 3923 3924 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 3925 } 3926 3927 /// Returns the supremum of two ranges: i.e. their conservative merge. 3928 static IntRange join(IntRange L, IntRange R) { 3929 return IntRange(std::max(L.Width, R.Width), 3930 L.NonNegative && R.NonNegative); 3931 } 3932 3933 /// Returns the infinum of two ranges: i.e. their aggressive merge. 3934 static IntRange meet(IntRange L, IntRange R) { 3935 return IntRange(std::min(L.Width, R.Width), 3936 L.NonNegative || R.NonNegative); 3937 } 3938}; 3939 3940static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, 3941 unsigned MaxWidth) { 3942 if (value.isSigned() && value.isNegative()) 3943 return IntRange(value.getMinSignedBits(), false); 3944 3945 if (value.getBitWidth() > MaxWidth) 3946 value = value.trunc(MaxWidth); 3947 3948 // isNonNegative() just checks the sign bit without considering 3949 // signedness. 3950 return IntRange(value.getActiveBits(), true); 3951} 3952 3953static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty, 3954 unsigned MaxWidth) { 3955 if (result.isInt()) 3956 return GetValueRange(C, result.getInt(), MaxWidth); 3957 3958 if (result.isVector()) { 3959 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth); 3960 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) { 3961 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth); 3962 R = IntRange::join(R, El); 3963 } 3964 return R; 3965 } 3966 3967 if (result.isComplexInt()) { 3968 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth); 3969 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth); 3970 return IntRange::join(R, I); 3971 } 3972 3973 // This can happen with lossless casts to intptr_t of "based" lvalues. 3974 // Assume it might use arbitrary bits. 3975 // FIXME: The only reason we need to pass the type in here is to get 3976 // the sign right on this one case. It would be nice if APValue 3977 // preserved this. 3978 assert(result.isLValue() || result.isAddrLabelDiff()); 3979 return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType()); 3980} 3981 3982/// Pseudo-evaluate the given integer expression, estimating the 3983/// range of values it might take. 3984/// 3985/// \param MaxWidth - the width to which the value will be truncated 3986static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) { 3987 E = E->IgnoreParens(); 3988 3989 // Try a full evaluation first. 3990 Expr::EvalResult result; 3991 if (E->EvaluateAsRValue(result, C)) 3992 return GetValueRange(C, result.Val, E->getType(), MaxWidth); 3993 3994 // I think we only want to look through implicit casts here; if the 3995 // user has an explicit widening cast, we should treat the value as 3996 // being of the new, wider type. 3997 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) { 3998 if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue) 3999 return GetExprRange(C, CE->getSubExpr(), MaxWidth); 4000 4001 IntRange OutputTypeRange = IntRange::forValueOfType(C, CE->getType()); 4002 4003 bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast); 4004 4005 // Assume that non-integer casts can span the full range of the type. 4006 if (!isIntegerCast) 4007 return OutputTypeRange; 4008 4009 IntRange SubRange 4010 = GetExprRange(C, CE->getSubExpr(), 4011 std::min(MaxWidth, OutputTypeRange.Width)); 4012 4013 // Bail out if the subexpr's range is as wide as the cast type. 4014 if (SubRange.Width >= OutputTypeRange.Width) 4015 return OutputTypeRange; 4016 4017 // Otherwise, we take the smaller width, and we're non-negative if 4018 // either the output type or the subexpr is. 4019 return IntRange(SubRange.Width, 4020 SubRange.NonNegative || OutputTypeRange.NonNegative); 4021 } 4022 4023 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 4024 // If we can fold the condition, just take that operand. 4025 bool CondResult; 4026 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C)) 4027 return GetExprRange(C, CondResult ? CO->getTrueExpr() 4028 : CO->getFalseExpr(), 4029 MaxWidth); 4030 4031 // Otherwise, conservatively merge. 4032 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth); 4033 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth); 4034 return IntRange::join(L, R); 4035 } 4036 4037 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 4038 switch (BO->getOpcode()) { 4039 4040 // Boolean-valued operations are single-bit and positive. 4041 case BO_LAnd: 4042 case BO_LOr: 4043 case BO_LT: 4044 case BO_GT: 4045 case BO_LE: 4046 case BO_GE: 4047 case BO_EQ: 4048 case BO_NE: 4049 return IntRange::forBoolType(); 4050 4051 // The type of the assignments is the type of the LHS, so the RHS 4052 // is not necessarily the same type. 4053 case BO_MulAssign: 4054 case BO_DivAssign: 4055 case BO_RemAssign: 4056 case BO_AddAssign: 4057 case BO_SubAssign: 4058 case BO_XorAssign: 4059 case BO_OrAssign: 4060 // TODO: bitfields? 4061 return IntRange::forValueOfType(C, E->getType()); 4062 4063 // Simple assignments just pass through the RHS, which will have 4064 // been coerced to the LHS type. 4065 case BO_Assign: 4066 // TODO: bitfields? 4067 return GetExprRange(C, BO->getRHS(), MaxWidth); 4068 4069 // Operations with opaque sources are black-listed. 4070 case BO_PtrMemD: 4071 case BO_PtrMemI: 4072 return IntRange::forValueOfType(C, E->getType()); 4073 4074 // Bitwise-and uses the *infinum* of the two source ranges. 4075 case BO_And: 4076 case BO_AndAssign: 4077 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth), 4078 GetExprRange(C, BO->getRHS(), MaxWidth)); 4079 4080 // Left shift gets black-listed based on a judgement call. 4081 case BO_Shl: 4082 // ...except that we want to treat '1 << (blah)' as logically 4083 // positive. It's an important idiom. 4084 if (IntegerLiteral *I 4085 = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) { 4086 if (I->getValue() == 1) { 4087 IntRange R = IntRange::forValueOfType(C, E->getType()); 4088 return IntRange(R.Width, /*NonNegative*/ true); 4089 } 4090 } 4091 // fallthrough 4092 4093 case BO_ShlAssign: 4094 return IntRange::forValueOfType(C, E->getType()); 4095 4096 // Right shift by a constant can narrow its left argument. 4097 case BO_Shr: 4098 case BO_ShrAssign: { 4099 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 4100 4101 // If the shift amount is a positive constant, drop the width by 4102 // that much. 4103 llvm::APSInt shift; 4104 if (BO->getRHS()->isIntegerConstantExpr(shift, C) && 4105 shift.isNonNegative()) { 4106 unsigned zext = shift.getZExtValue(); 4107 if (zext >= L.Width) 4108 L.Width = (L.NonNegative ? 0 : 1); 4109 else 4110 L.Width -= zext; 4111 } 4112 4113 return L; 4114 } 4115 4116 // Comma acts as its right operand. 4117 case BO_Comma: 4118 return GetExprRange(C, BO->getRHS(), MaxWidth); 4119 4120 // Black-list pointer subtractions. 4121 case BO_Sub: 4122 if (BO->getLHS()->getType()->isPointerType()) 4123 return IntRange::forValueOfType(C, E->getType()); 4124 break; 4125 4126 // The width of a division result is mostly determined by the size 4127 // of the LHS. 4128 case BO_Div: { 4129 // Don't 'pre-truncate' the operands. 4130 unsigned opWidth = C.getIntWidth(E->getType()); 4131 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 4132 4133 // If the divisor is constant, use that. 4134 llvm::APSInt divisor; 4135 if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) { 4136 unsigned log2 = divisor.logBase2(); // floor(log_2(divisor)) 4137 if (log2 >= L.Width) 4138 L.Width = (L.NonNegative ? 0 : 1); 4139 else 4140 L.Width = std::min(L.Width - log2, MaxWidth); 4141 return L; 4142 } 4143 4144 // Otherwise, just use the LHS's width. 4145 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 4146 return IntRange(L.Width, L.NonNegative && R.NonNegative); 4147 } 4148 4149 // The result of a remainder can't be larger than the result of 4150 // either side. 4151 case BO_Rem: { 4152 // Don't 'pre-truncate' the operands. 4153 unsigned opWidth = C.getIntWidth(E->getType()); 4154 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 4155 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 4156 4157 IntRange meet = IntRange::meet(L, R); 4158 meet.Width = std::min(meet.Width, MaxWidth); 4159 return meet; 4160 } 4161 4162 // The default behavior is okay for these. 4163 case BO_Mul: 4164 case BO_Add: 4165 case BO_Xor: 4166 case BO_Or: 4167 break; 4168 } 4169 4170 // The default case is to treat the operation as if it were closed 4171 // on the narrowest type that encompasses both operands. 4172 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 4173 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth); 4174 return IntRange::join(L, R); 4175 } 4176 4177 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 4178 switch (UO->getOpcode()) { 4179 // Boolean-valued operations are white-listed. 4180 case UO_LNot: 4181 return IntRange::forBoolType(); 4182 4183 // Operations with opaque sources are black-listed. 4184 case UO_Deref: 4185 case UO_AddrOf: // should be impossible 4186 return IntRange::forValueOfType(C, E->getType()); 4187 4188 default: 4189 return GetExprRange(C, UO->getSubExpr(), MaxWidth); 4190 } 4191 } 4192 4193 if (dyn_cast<OffsetOfExpr>(E)) { 4194 IntRange::forValueOfType(C, E->getType()); 4195 } 4196 4197 if (FieldDecl *BitField = E->getBitField()) 4198 return IntRange(BitField->getBitWidthValue(C), 4199 BitField->getType()->isUnsignedIntegerOrEnumerationType()); 4200 4201 return IntRange::forValueOfType(C, E->getType()); 4202} 4203 4204static IntRange GetExprRange(ASTContext &C, Expr *E) { 4205 return GetExprRange(C, E, C.getIntWidth(E->getType())); 4206} 4207 4208/// Checks whether the given value, which currently has the given 4209/// source semantics, has the same value when coerced through the 4210/// target semantics. 4211static bool IsSameFloatAfterCast(const llvm::APFloat &value, 4212 const llvm::fltSemantics &Src, 4213 const llvm::fltSemantics &Tgt) { 4214 llvm::APFloat truncated = value; 4215 4216 bool ignored; 4217 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored); 4218 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored); 4219 4220 return truncated.bitwiseIsEqual(value); 4221} 4222 4223/// Checks whether the given value, which currently has the given 4224/// source semantics, has the same value when coerced through the 4225/// target semantics. 4226/// 4227/// The value might be a vector of floats (or a complex number). 4228static bool IsSameFloatAfterCast(const APValue &value, 4229 const llvm::fltSemantics &Src, 4230 const llvm::fltSemantics &Tgt) { 4231 if (value.isFloat()) 4232 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt); 4233 4234 if (value.isVector()) { 4235 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i) 4236 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt)) 4237 return false; 4238 return true; 4239 } 4240 4241 assert(value.isComplexFloat()); 4242 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) && 4243 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt)); 4244} 4245 4246static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC); 4247 4248static bool IsZero(Sema &S, Expr *E) { 4249 // Suppress cases where we are comparing against an enum constant. 4250 if (const DeclRefExpr *DR = 4251 dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts())) 4252 if (isa<EnumConstantDecl>(DR->getDecl())) 4253 return false; 4254 4255 // Suppress cases where the '0' value is expanded from a macro. 4256 if (E->getLocStart().isMacroID()) 4257 return false; 4258 4259 llvm::APSInt Value; 4260 return E->isIntegerConstantExpr(Value, S.Context) && Value == 0; 4261} 4262 4263static bool HasEnumType(Expr *E) { 4264 // Strip off implicit integral promotions. 4265 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 4266 if (ICE->getCastKind() != CK_IntegralCast && 4267 ICE->getCastKind() != CK_NoOp) 4268 break; 4269 E = ICE->getSubExpr(); 4270 } 4271 4272 return E->getType()->isEnumeralType(); 4273} 4274 4275static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) { 4276 BinaryOperatorKind op = E->getOpcode(); 4277 if (E->isValueDependent()) 4278 return; 4279 4280 if (op == BO_LT && IsZero(S, E->getRHS())) { 4281 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 4282 << "< 0" << "false" << HasEnumType(E->getLHS()) 4283 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4284 } else if (op == BO_GE && IsZero(S, E->getRHS())) { 4285 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 4286 << ">= 0" << "true" << HasEnumType(E->getLHS()) 4287 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4288 } else if (op == BO_GT && IsZero(S, E->getLHS())) { 4289 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 4290 << "0 >" << "false" << HasEnumType(E->getRHS()) 4291 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4292 } else if (op == BO_LE && IsZero(S, E->getLHS())) { 4293 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 4294 << "0 <=" << "true" << HasEnumType(E->getRHS()) 4295 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4296 } 4297} 4298 4299/// Analyze the operands of the given comparison. Implements the 4300/// fallback case from AnalyzeComparison. 4301static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) { 4302 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 4303 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 4304} 4305 4306/// \brief Implements -Wsign-compare. 4307/// 4308/// \param E the binary operator to check for warnings 4309static void AnalyzeComparison(Sema &S, BinaryOperator *E) { 4310 // The type the comparison is being performed in. 4311 QualType T = E->getLHS()->getType(); 4312 assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType()) 4313 && "comparison with mismatched types"); 4314 4315 // We don't do anything special if this isn't an unsigned integral 4316 // comparison: we're only interested in integral comparisons, and 4317 // signed comparisons only happen in cases we don't care to warn about. 4318 // 4319 // We also don't care about value-dependent expressions or expressions 4320 // whose result is a constant. 4321 if (!T->hasUnsignedIntegerRepresentation() 4322 || E->isValueDependent() || E->isIntegerConstantExpr(S.Context)) 4323 return AnalyzeImpConvsInComparison(S, E); 4324 4325 Expr *LHS = E->getLHS()->IgnoreParenImpCasts(); 4326 Expr *RHS = E->getRHS()->IgnoreParenImpCasts(); 4327 4328 // Check to see if one of the (unmodified) operands is of different 4329 // signedness. 4330 Expr *signedOperand, *unsignedOperand; 4331 if (LHS->getType()->hasSignedIntegerRepresentation()) { 4332 assert(!RHS->getType()->hasSignedIntegerRepresentation() && 4333 "unsigned comparison between two signed integer expressions?"); 4334 signedOperand = LHS; 4335 unsignedOperand = RHS; 4336 } else if (RHS->getType()->hasSignedIntegerRepresentation()) { 4337 signedOperand = RHS; 4338 unsignedOperand = LHS; 4339 } else { 4340 CheckTrivialUnsignedComparison(S, E); 4341 return AnalyzeImpConvsInComparison(S, E); 4342 } 4343 4344 // Otherwise, calculate the effective range of the signed operand. 4345 IntRange signedRange = GetExprRange(S.Context, signedOperand); 4346 4347 // Go ahead and analyze implicit conversions in the operands. Note 4348 // that we skip the implicit conversions on both sides. 4349 AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc()); 4350 AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc()); 4351 4352 // If the signed range is non-negative, -Wsign-compare won't fire, 4353 // but we should still check for comparisons which are always true 4354 // or false. 4355 if (signedRange.NonNegative) 4356 return CheckTrivialUnsignedComparison(S, E); 4357 4358 // For (in)equality comparisons, if the unsigned operand is a 4359 // constant which cannot collide with a overflowed signed operand, 4360 // then reinterpreting the signed operand as unsigned will not 4361 // change the result of the comparison. 4362 if (E->isEqualityOp()) { 4363 unsigned comparisonWidth = S.Context.getIntWidth(T); 4364 IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand); 4365 4366 // We should never be unable to prove that the unsigned operand is 4367 // non-negative. 4368 assert(unsignedRange.NonNegative && "unsigned range includes negative?"); 4369 4370 if (unsignedRange.Width < comparisonWidth) 4371 return; 4372 } 4373 4374 S.DiagRuntimeBehavior(E->getOperatorLoc(), E, 4375 S.PDiag(diag::warn_mixed_sign_comparison) 4376 << LHS->getType() << RHS->getType() 4377 << LHS->getSourceRange() << RHS->getSourceRange()); 4378} 4379 4380/// Analyzes an attempt to assign the given value to a bitfield. 4381/// 4382/// Returns true if there was something fishy about the attempt. 4383static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init, 4384 SourceLocation InitLoc) { 4385 assert(Bitfield->isBitField()); 4386 if (Bitfield->isInvalidDecl()) 4387 return false; 4388 4389 // White-list bool bitfields. 4390 if (Bitfield->getType()->isBooleanType()) 4391 return false; 4392 4393 // Ignore value- or type-dependent expressions. 4394 if (Bitfield->getBitWidth()->isValueDependent() || 4395 Bitfield->getBitWidth()->isTypeDependent() || 4396 Init->isValueDependent() || 4397 Init->isTypeDependent()) 4398 return false; 4399 4400 Expr *OriginalInit = Init->IgnoreParenImpCasts(); 4401 4402 llvm::APSInt Value; 4403 if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects)) 4404 return false; 4405 4406 unsigned OriginalWidth = Value.getBitWidth(); 4407 unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context); 4408 4409 if (OriginalWidth <= FieldWidth) 4410 return false; 4411 4412 // Compute the value which the bitfield will contain. 4413 llvm::APSInt TruncatedValue = Value.trunc(FieldWidth); 4414 TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType()); 4415 4416 // Check whether the stored value is equal to the original value. 4417 TruncatedValue = TruncatedValue.extend(OriginalWidth); 4418 if (llvm::APSInt::isSameValue(Value, TruncatedValue)) 4419 return false; 4420 4421 // Special-case bitfields of width 1: booleans are naturally 0/1, and 4422 // therefore don't strictly fit into a signed bitfield of width 1. 4423 if (FieldWidth == 1 && Value == 1) 4424 return false; 4425 4426 std::string PrettyValue = Value.toString(10); 4427 std::string PrettyTrunc = TruncatedValue.toString(10); 4428 4429 S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant) 4430 << PrettyValue << PrettyTrunc << OriginalInit->getType() 4431 << Init->getSourceRange(); 4432 4433 return true; 4434} 4435 4436/// Analyze the given simple or compound assignment for warning-worthy 4437/// operations. 4438static void AnalyzeAssignment(Sema &S, BinaryOperator *E) { 4439 // Just recurse on the LHS. 4440 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 4441 4442 // We want to recurse on the RHS as normal unless we're assigning to 4443 // a bitfield. 4444 if (FieldDecl *Bitfield = E->getLHS()->getBitField()) { 4445 if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(), 4446 E->getOperatorLoc())) { 4447 // Recurse, ignoring any implicit conversions on the RHS. 4448 return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(), 4449 E->getOperatorLoc()); 4450 } 4451 } 4452 4453 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 4454} 4455 4456/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 4457static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T, 4458 SourceLocation CContext, unsigned diag, 4459 bool pruneControlFlow = false) { 4460 if (pruneControlFlow) { 4461 S.DiagRuntimeBehavior(E->getExprLoc(), E, 4462 S.PDiag(diag) 4463 << SourceType << T << E->getSourceRange() 4464 << SourceRange(CContext)); 4465 return; 4466 } 4467 S.Diag(E->getExprLoc(), diag) 4468 << SourceType << T << E->getSourceRange() << SourceRange(CContext); 4469} 4470 4471/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 4472static void DiagnoseImpCast(Sema &S, Expr *E, QualType T, 4473 SourceLocation CContext, unsigned diag, 4474 bool pruneControlFlow = false) { 4475 DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow); 4476} 4477 4478/// Diagnose an implicit cast from a literal expression. Does not warn when the 4479/// cast wouldn't lose information. 4480void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T, 4481 SourceLocation CContext) { 4482 // Try to convert the literal exactly to an integer. If we can, don't warn. 4483 bool isExact = false; 4484 const llvm::APFloat &Value = FL->getValue(); 4485 llvm::APSInt IntegerValue(S.Context.getIntWidth(T), 4486 T->hasUnsignedIntegerRepresentation()); 4487 if (Value.convertToInteger(IntegerValue, 4488 llvm::APFloat::rmTowardZero, &isExact) 4489 == llvm::APFloat::opOK && isExact) 4490 return; 4491 4492 SmallString<16> PrettySourceValue; 4493 Value.toString(PrettySourceValue); 4494 SmallString<16> PrettyTargetValue; 4495 if (T->isSpecificBuiltinType(BuiltinType::Bool)) 4496 PrettyTargetValue = IntegerValue == 0 ? "false" : "true"; 4497 else 4498 IntegerValue.toString(PrettyTargetValue); 4499 4500 S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer) 4501 << FL->getType() << T.getUnqualifiedType() << PrettySourceValue 4502 << PrettyTargetValue << FL->getSourceRange() << SourceRange(CContext); 4503} 4504 4505std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) { 4506 if (!Range.Width) return "0"; 4507 4508 llvm::APSInt ValueInRange = Value; 4509 ValueInRange.setIsSigned(!Range.NonNegative); 4510 ValueInRange = ValueInRange.trunc(Range.Width); 4511 return ValueInRange.toString(10); 4512} 4513 4514static bool IsImplicitBoolFloatConversion(Sema &S, Expr *Ex, bool ToBool) { 4515 if (!isa<ImplicitCastExpr>(Ex)) 4516 return false; 4517 4518 Expr *InnerE = Ex->IgnoreParenImpCasts(); 4519 const Type *Target = S.Context.getCanonicalType(Ex->getType()).getTypePtr(); 4520 const Type *Source = 4521 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 4522 if (Target->isDependentType()) 4523 return false; 4524 4525 const BuiltinType *FloatCandidateBT = 4526 dyn_cast<BuiltinType>(ToBool ? Source : Target); 4527 const Type *BoolCandidateType = ToBool ? Target : Source; 4528 4529 return (BoolCandidateType->isSpecificBuiltinType(BuiltinType::Bool) && 4530 FloatCandidateBT && (FloatCandidateBT->isFloatingPoint())); 4531} 4532 4533void CheckImplicitArgumentConversions(Sema &S, CallExpr *TheCall, 4534 SourceLocation CC) { 4535 unsigned NumArgs = TheCall->getNumArgs(); 4536 for (unsigned i = 0; i < NumArgs; ++i) { 4537 Expr *CurrA = TheCall->getArg(i); 4538 if (!IsImplicitBoolFloatConversion(S, CurrA, true)) 4539 continue; 4540 4541 bool IsSwapped = ((i > 0) && 4542 IsImplicitBoolFloatConversion(S, TheCall->getArg(i - 1), false)); 4543 IsSwapped |= ((i < (NumArgs - 1)) && 4544 IsImplicitBoolFloatConversion(S, TheCall->getArg(i + 1), false)); 4545 if (IsSwapped) { 4546 // Warn on this floating-point to bool conversion. 4547 DiagnoseImpCast(S, CurrA->IgnoreParenImpCasts(), 4548 CurrA->getType(), CC, 4549 diag::warn_impcast_floating_point_to_bool); 4550 } 4551 } 4552} 4553 4554void CheckImplicitConversion(Sema &S, Expr *E, QualType T, 4555 SourceLocation CC, bool *ICContext = 0) { 4556 if (E->isTypeDependent() || E->isValueDependent()) return; 4557 4558 const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr(); 4559 const Type *Target = S.Context.getCanonicalType(T).getTypePtr(); 4560 if (Source == Target) return; 4561 if (Target->isDependentType()) return; 4562 4563 // If the conversion context location is invalid don't complain. We also 4564 // don't want to emit a warning if the issue occurs from the expansion of 4565 // a system macro. The problem is that 'getSpellingLoc()' is slow, so we 4566 // delay this check as long as possible. Once we detect we are in that 4567 // scenario, we just return. 4568 if (CC.isInvalid()) 4569 return; 4570 4571 // Diagnose implicit casts to bool. 4572 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) { 4573 if (isa<StringLiteral>(E)) 4574 // Warn on string literal to bool. Checks for string literals in logical 4575 // expressions, for instances, assert(0 && "error here"), is prevented 4576 // by a check in AnalyzeImplicitConversions(). 4577 return DiagnoseImpCast(S, E, T, CC, 4578 diag::warn_impcast_string_literal_to_bool); 4579 if (Source->isFunctionType()) { 4580 // Warn on function to bool. Checks free functions and static member 4581 // functions. Weakly imported functions are excluded from the check, 4582 // since it's common to test their value to check whether the linker 4583 // found a definition for them. 4584 ValueDecl *D = 0; 4585 if (DeclRefExpr* R = dyn_cast<DeclRefExpr>(E)) { 4586 D = R->getDecl(); 4587 } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) { 4588 D = M->getMemberDecl(); 4589 } 4590 4591 if (D && !D->isWeak()) { 4592 if (FunctionDecl* F = dyn_cast<FunctionDecl>(D)) { 4593 S.Diag(E->getExprLoc(), diag::warn_impcast_function_to_bool) 4594 << F << E->getSourceRange() << SourceRange(CC); 4595 S.Diag(E->getExprLoc(), diag::note_function_to_bool_silence) 4596 << FixItHint::CreateInsertion(E->getExprLoc(), "&"); 4597 QualType ReturnType; 4598 UnresolvedSet<4> NonTemplateOverloads; 4599 S.isExprCallable(*E, ReturnType, NonTemplateOverloads); 4600 if (!ReturnType.isNull() 4601 && ReturnType->isSpecificBuiltinType(BuiltinType::Bool)) 4602 S.Diag(E->getExprLoc(), diag::note_function_to_bool_call) 4603 << FixItHint::CreateInsertion( 4604 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()), "()"); 4605 return; 4606 } 4607 } 4608 } 4609 } 4610 4611 // Strip vector types. 4612 if (isa<VectorType>(Source)) { 4613 if (!isa<VectorType>(Target)) { 4614 if (S.SourceMgr.isInSystemMacro(CC)) 4615 return; 4616 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar); 4617 } 4618 4619 // If the vector cast is cast between two vectors of the same size, it is 4620 // a bitcast, not a conversion. 4621 if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target)) 4622 return; 4623 4624 Source = cast<VectorType>(Source)->getElementType().getTypePtr(); 4625 Target = cast<VectorType>(Target)->getElementType().getTypePtr(); 4626 } 4627 4628 // Strip complex types. 4629 if (isa<ComplexType>(Source)) { 4630 if (!isa<ComplexType>(Target)) { 4631 if (S.SourceMgr.isInSystemMacro(CC)) 4632 return; 4633 4634 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar); 4635 } 4636 4637 Source = cast<ComplexType>(Source)->getElementType().getTypePtr(); 4638 Target = cast<ComplexType>(Target)->getElementType().getTypePtr(); 4639 } 4640 4641 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source); 4642 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target); 4643 4644 // If the source is floating point... 4645 if (SourceBT && SourceBT->isFloatingPoint()) { 4646 // ...and the target is floating point... 4647 if (TargetBT && TargetBT->isFloatingPoint()) { 4648 // ...then warn if we're dropping FP rank. 4649 4650 // Builtin FP kinds are ordered by increasing FP rank. 4651 if (SourceBT->getKind() > TargetBT->getKind()) { 4652 // Don't warn about float constants that are precisely 4653 // representable in the target type. 4654 Expr::EvalResult result; 4655 if (E->EvaluateAsRValue(result, S.Context)) { 4656 // Value might be a float, a float vector, or a float complex. 4657 if (IsSameFloatAfterCast(result.Val, 4658 S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)), 4659 S.Context.getFloatTypeSemantics(QualType(SourceBT, 0)))) 4660 return; 4661 } 4662 4663 if (S.SourceMgr.isInSystemMacro(CC)) 4664 return; 4665 4666 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision); 4667 } 4668 return; 4669 } 4670 4671 // If the target is integral, always warn. 4672 if (TargetBT && TargetBT->isInteger()) { 4673 if (S.SourceMgr.isInSystemMacro(CC)) 4674 return; 4675 4676 Expr *InnerE = E->IgnoreParenImpCasts(); 4677 // We also want to warn on, e.g., "int i = -1.234" 4678 if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE)) 4679 if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus) 4680 InnerE = UOp->getSubExpr()->IgnoreParenImpCasts(); 4681 4682 if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) { 4683 DiagnoseFloatingLiteralImpCast(S, FL, T, CC); 4684 } else { 4685 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer); 4686 } 4687 } 4688 4689 // If the target is bool, warn if expr is a function or method call. 4690 if (Target->isSpecificBuiltinType(BuiltinType::Bool) && 4691 isa<CallExpr>(E)) { 4692 // Check last argument of function call to see if it is an 4693 // implicit cast from a type matching the type the result 4694 // is being cast to. 4695 CallExpr *CEx = cast<CallExpr>(E); 4696 unsigned NumArgs = CEx->getNumArgs(); 4697 if (NumArgs > 0) { 4698 Expr *LastA = CEx->getArg(NumArgs - 1); 4699 Expr *InnerE = LastA->IgnoreParenImpCasts(); 4700 const Type *InnerType = 4701 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 4702 if (isa<ImplicitCastExpr>(LastA) && (InnerType == Target)) { 4703 // Warn on this floating-point to bool conversion 4704 DiagnoseImpCast(S, E, T, CC, 4705 diag::warn_impcast_floating_point_to_bool); 4706 } 4707 } 4708 } 4709 return; 4710 } 4711 4712 if ((E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull) 4713 == Expr::NPCK_GNUNull) && !Target->isAnyPointerType() 4714 && !Target->isBlockPointerType() && !Target->isMemberPointerType()) { 4715 SourceLocation Loc = E->getSourceRange().getBegin(); 4716 if (Loc.isMacroID()) 4717 Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first; 4718 if (!Loc.isMacroID() || CC.isMacroID()) 4719 S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer) 4720 << T << clang::SourceRange(CC) 4721 << FixItHint::CreateReplacement(Loc, S.getFixItZeroLiteralForType(T)); 4722 } 4723 4724 if (!Source->isIntegerType() || !Target->isIntegerType()) 4725 return; 4726 4727 // TODO: remove this early return once the false positives for constant->bool 4728 // in templates, macros, etc, are reduced or removed. 4729 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) 4730 return; 4731 4732 IntRange SourceRange = GetExprRange(S.Context, E); 4733 IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target); 4734 4735 if (SourceRange.Width > TargetRange.Width) { 4736 // If the source is a constant, use a default-on diagnostic. 4737 // TODO: this should happen for bitfield stores, too. 4738 llvm::APSInt Value(32); 4739 if (E->isIntegerConstantExpr(Value, S.Context)) { 4740 if (S.SourceMgr.isInSystemMacro(CC)) 4741 return; 4742 4743 std::string PrettySourceValue = Value.toString(10); 4744 std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange); 4745 4746 S.DiagRuntimeBehavior(E->getExprLoc(), E, 4747 S.PDiag(diag::warn_impcast_integer_precision_constant) 4748 << PrettySourceValue << PrettyTargetValue 4749 << E->getType() << T << E->getSourceRange() 4750 << clang::SourceRange(CC)); 4751 return; 4752 } 4753 4754 // People want to build with -Wshorten-64-to-32 and not -Wconversion. 4755 if (S.SourceMgr.isInSystemMacro(CC)) 4756 return; 4757 4758 if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64) 4759 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32, 4760 /* pruneControlFlow */ true); 4761 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision); 4762 } 4763 4764 if ((TargetRange.NonNegative && !SourceRange.NonNegative) || 4765 (!TargetRange.NonNegative && SourceRange.NonNegative && 4766 SourceRange.Width == TargetRange.Width)) { 4767 4768 if (S.SourceMgr.isInSystemMacro(CC)) 4769 return; 4770 4771 unsigned DiagID = diag::warn_impcast_integer_sign; 4772 4773 // Traditionally, gcc has warned about this under -Wsign-compare. 4774 // We also want to warn about it in -Wconversion. 4775 // So if -Wconversion is off, use a completely identical diagnostic 4776 // in the sign-compare group. 4777 // The conditional-checking code will 4778 if (ICContext) { 4779 DiagID = diag::warn_impcast_integer_sign_conditional; 4780 *ICContext = true; 4781 } 4782 4783 return DiagnoseImpCast(S, E, T, CC, DiagID); 4784 } 4785 4786 // Diagnose conversions between different enumeration types. 4787 // In C, we pretend that the type of an EnumConstantDecl is its enumeration 4788 // type, to give us better diagnostics. 4789 QualType SourceType = E->getType(); 4790 if (!S.getLangOpts().CPlusPlus) { 4791 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 4792 if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) { 4793 EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext()); 4794 SourceType = S.Context.getTypeDeclType(Enum); 4795 Source = S.Context.getCanonicalType(SourceType).getTypePtr(); 4796 } 4797 } 4798 4799 if (const EnumType *SourceEnum = Source->getAs<EnumType>()) 4800 if (const EnumType *TargetEnum = Target->getAs<EnumType>()) 4801 if ((SourceEnum->getDecl()->getIdentifier() || 4802 SourceEnum->getDecl()->getTypedefNameForAnonDecl()) && 4803 (TargetEnum->getDecl()->getIdentifier() || 4804 TargetEnum->getDecl()->getTypedefNameForAnonDecl()) && 4805 SourceEnum != TargetEnum) { 4806 if (S.SourceMgr.isInSystemMacro(CC)) 4807 return; 4808 4809 return DiagnoseImpCast(S, E, SourceType, T, CC, 4810 diag::warn_impcast_different_enum_types); 4811 } 4812 4813 return; 4814} 4815 4816void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 4817 SourceLocation CC, QualType T); 4818 4819void CheckConditionalOperand(Sema &S, Expr *E, QualType T, 4820 SourceLocation CC, bool &ICContext) { 4821 E = E->IgnoreParenImpCasts(); 4822 4823 if (isa<ConditionalOperator>(E)) 4824 return CheckConditionalOperator(S, cast<ConditionalOperator>(E), CC, T); 4825 4826 AnalyzeImplicitConversions(S, E, CC); 4827 if (E->getType() != T) 4828 return CheckImplicitConversion(S, E, T, CC, &ICContext); 4829 return; 4830} 4831 4832void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 4833 SourceLocation CC, QualType T) { 4834 AnalyzeImplicitConversions(S, E->getCond(), CC); 4835 4836 bool Suspicious = false; 4837 CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious); 4838 CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious); 4839 4840 // If -Wconversion would have warned about either of the candidates 4841 // for a signedness conversion to the context type... 4842 if (!Suspicious) return; 4843 4844 // ...but it's currently ignored... 4845 if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional, 4846 CC)) 4847 return; 4848 4849 // ...then check whether it would have warned about either of the 4850 // candidates for a signedness conversion to the condition type. 4851 if (E->getType() == T) return; 4852 4853 Suspicious = false; 4854 CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(), 4855 E->getType(), CC, &Suspicious); 4856 if (!Suspicious) 4857 CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(), 4858 E->getType(), CC, &Suspicious); 4859} 4860 4861/// AnalyzeImplicitConversions - Find and report any interesting 4862/// implicit conversions in the given expression. There are a couple 4863/// of competing diagnostics here, -Wconversion and -Wsign-compare. 4864void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) { 4865 QualType T = OrigE->getType(); 4866 Expr *E = OrigE->IgnoreParenImpCasts(); 4867 4868 if (E->isTypeDependent() || E->isValueDependent()) 4869 return; 4870 4871 // For conditional operators, we analyze the arguments as if they 4872 // were being fed directly into the output. 4873 if (isa<ConditionalOperator>(E)) { 4874 ConditionalOperator *CO = cast<ConditionalOperator>(E); 4875 CheckConditionalOperator(S, CO, CC, T); 4876 return; 4877 } 4878 4879 // Check implicit argument conversions for function calls. 4880 if (CallExpr *Call = dyn_cast<CallExpr>(E)) 4881 CheckImplicitArgumentConversions(S, Call, CC); 4882 4883 // Go ahead and check any implicit conversions we might have skipped. 4884 // The non-canonical typecheck is just an optimization; 4885 // CheckImplicitConversion will filter out dead implicit conversions. 4886 if (E->getType() != T) 4887 CheckImplicitConversion(S, E, T, CC); 4888 4889 // Now continue drilling into this expression. 4890 4891 // Skip past explicit casts. 4892 if (isa<ExplicitCastExpr>(E)) { 4893 E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts(); 4894 return AnalyzeImplicitConversions(S, E, CC); 4895 } 4896 4897 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 4898 // Do a somewhat different check with comparison operators. 4899 if (BO->isComparisonOp()) 4900 return AnalyzeComparison(S, BO); 4901 4902 // And with simple assignments. 4903 if (BO->getOpcode() == BO_Assign) 4904 return AnalyzeAssignment(S, BO); 4905 } 4906 4907 // These break the otherwise-useful invariant below. Fortunately, 4908 // we don't really need to recurse into them, because any internal 4909 // expressions should have been analyzed already when they were 4910 // built into statements. 4911 if (isa<StmtExpr>(E)) return; 4912 4913 // Don't descend into unevaluated contexts. 4914 if (isa<UnaryExprOrTypeTraitExpr>(E)) return; 4915 4916 // Now just recurse over the expression's children. 4917 CC = E->getExprLoc(); 4918 BinaryOperator *BO = dyn_cast<BinaryOperator>(E); 4919 bool IsLogicalOperator = BO && BO->isLogicalOp(); 4920 for (Stmt::child_range I = E->children(); I; ++I) { 4921 Expr *ChildExpr = dyn_cast_or_null<Expr>(*I); 4922 if (!ChildExpr) 4923 continue; 4924 4925 if (IsLogicalOperator && 4926 isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts())) 4927 // Ignore checking string literals that are in logical operators. 4928 continue; 4929 AnalyzeImplicitConversions(S, ChildExpr, CC); 4930 } 4931} 4932 4933} // end anonymous namespace 4934 4935/// Diagnoses "dangerous" implicit conversions within the given 4936/// expression (which is a full expression). Implements -Wconversion 4937/// and -Wsign-compare. 4938/// 4939/// \param CC the "context" location of the implicit conversion, i.e. 4940/// the most location of the syntactic entity requiring the implicit 4941/// conversion 4942void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) { 4943 // Don't diagnose in unevaluated contexts. 4944 if (isUnevaluatedContext()) 4945 return; 4946 4947 // Don't diagnose for value- or type-dependent expressions. 4948 if (E->isTypeDependent() || E->isValueDependent()) 4949 return; 4950 4951 // Check for array bounds violations in cases where the check isn't triggered 4952 // elsewhere for other Expr types (like BinaryOperators), e.g. when an 4953 // ArraySubscriptExpr is on the RHS of a variable initialization. 4954 CheckArrayAccess(E); 4955 4956 // This is not the right CC for (e.g.) a variable initialization. 4957 AnalyzeImplicitConversions(*this, E, CC); 4958} 4959 4960void Sema::CheckBitFieldInitialization(SourceLocation InitLoc, 4961 FieldDecl *BitField, 4962 Expr *Init) { 4963 (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc); 4964} 4965 4966/// CheckParmsForFunctionDef - Check that the parameters of the given 4967/// function are appropriate for the definition of a function. This 4968/// takes care of any checks that cannot be performed on the 4969/// declaration itself, e.g., that the types of each of the function 4970/// parameters are complete. 4971bool Sema::CheckParmsForFunctionDef(ParmVarDecl **P, ParmVarDecl **PEnd, 4972 bool CheckParameterNames) { 4973 bool HasInvalidParm = false; 4974 for (; P != PEnd; ++P) { 4975 ParmVarDecl *Param = *P; 4976 4977 // C99 6.7.5.3p4: the parameters in a parameter type list in a 4978 // function declarator that is part of a function definition of 4979 // that function shall not have incomplete type. 4980 // 4981 // This is also C++ [dcl.fct]p6. 4982 if (!Param->isInvalidDecl() && 4983 RequireCompleteType(Param->getLocation(), Param->getType(), 4984 diag::err_typecheck_decl_incomplete_type)) { 4985 Param->setInvalidDecl(); 4986 HasInvalidParm = true; 4987 } 4988 4989 // C99 6.9.1p5: If the declarator includes a parameter type list, the 4990 // declaration of each parameter shall include an identifier. 4991 if (CheckParameterNames && 4992 Param->getIdentifier() == 0 && 4993 !Param->isImplicit() && 4994 !getLangOpts().CPlusPlus) 4995 Diag(Param->getLocation(), diag::err_parameter_name_omitted); 4996 4997 // C99 6.7.5.3p12: 4998 // If the function declarator is not part of a definition of that 4999 // function, parameters may have incomplete type and may use the [*] 5000 // notation in their sequences of declarator specifiers to specify 5001 // variable length array types. 5002 QualType PType = Param->getOriginalType(); 5003 if (const ArrayType *AT = Context.getAsArrayType(PType)) { 5004 if (AT->getSizeModifier() == ArrayType::Star) { 5005 // FIXME: This diagnosic should point the '[*]' if source-location 5006 // information is added for it. 5007 Diag(Param->getLocation(), diag::err_array_star_in_function_definition); 5008 } 5009 } 5010 } 5011 5012 return HasInvalidParm; 5013} 5014 5015/// CheckCastAlign - Implements -Wcast-align, which warns when a 5016/// pointer cast increases the alignment requirements. 5017void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) { 5018 // This is actually a lot of work to potentially be doing on every 5019 // cast; don't do it if we're ignoring -Wcast_align (as is the default). 5020 if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align, 5021 TRange.getBegin()) 5022 == DiagnosticsEngine::Ignored) 5023 return; 5024 5025 // Ignore dependent types. 5026 if (T->isDependentType() || Op->getType()->isDependentType()) 5027 return; 5028 5029 // Require that the destination be a pointer type. 5030 const PointerType *DestPtr = T->getAs<PointerType>(); 5031 if (!DestPtr) return; 5032 5033 // If the destination has alignment 1, we're done. 5034 QualType DestPointee = DestPtr->getPointeeType(); 5035 if (DestPointee->isIncompleteType()) return; 5036 CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee); 5037 if (DestAlign.isOne()) return; 5038 5039 // Require that the source be a pointer type. 5040 const PointerType *SrcPtr = Op->getType()->getAs<PointerType>(); 5041 if (!SrcPtr) return; 5042 QualType SrcPointee = SrcPtr->getPointeeType(); 5043 5044 // Whitelist casts from cv void*. We already implicitly 5045 // whitelisted casts to cv void*, since they have alignment 1. 5046 // Also whitelist casts involving incomplete types, which implicitly 5047 // includes 'void'. 5048 if (SrcPointee->isIncompleteType()) return; 5049 5050 CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee); 5051 if (SrcAlign >= DestAlign) return; 5052 5053 Diag(TRange.getBegin(), diag::warn_cast_align) 5054 << Op->getType() << T 5055 << static_cast<unsigned>(SrcAlign.getQuantity()) 5056 << static_cast<unsigned>(DestAlign.getQuantity()) 5057 << TRange << Op->getSourceRange(); 5058} 5059 5060static const Type* getElementType(const Expr *BaseExpr) { 5061 const Type* EltType = BaseExpr->getType().getTypePtr(); 5062 if (EltType->isAnyPointerType()) 5063 return EltType->getPointeeType().getTypePtr(); 5064 else if (EltType->isArrayType()) 5065 return EltType->getBaseElementTypeUnsafe(); 5066 return EltType; 5067} 5068 5069/// \brief Check whether this array fits the idiom of a size-one tail padded 5070/// array member of a struct. 5071/// 5072/// We avoid emitting out-of-bounds access warnings for such arrays as they are 5073/// commonly used to emulate flexible arrays in C89 code. 5074static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size, 5075 const NamedDecl *ND) { 5076 if (Size != 1 || !ND) return false; 5077 5078 const FieldDecl *FD = dyn_cast<FieldDecl>(ND); 5079 if (!FD) return false; 5080 5081 // Don't consider sizes resulting from macro expansions or template argument 5082 // substitution to form C89 tail-padded arrays. 5083 5084 TypeSourceInfo *TInfo = FD->getTypeSourceInfo(); 5085 while (TInfo) { 5086 TypeLoc TL = TInfo->getTypeLoc(); 5087 // Look through typedefs. 5088 const TypedefTypeLoc *TTL = dyn_cast<TypedefTypeLoc>(&TL); 5089 if (TTL) { 5090 const TypedefNameDecl *TDL = TTL->getTypedefNameDecl(); 5091 TInfo = TDL->getTypeSourceInfo(); 5092 continue; 5093 } 5094 ConstantArrayTypeLoc CTL = cast<ConstantArrayTypeLoc>(TL); 5095 const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr()); 5096 if (!SizeExpr || SizeExpr->getExprLoc().isMacroID()) 5097 return false; 5098 break; 5099 } 5100 5101 const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext()); 5102 if (!RD) return false; 5103 if (RD->isUnion()) return false; 5104 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) { 5105 if (!CRD->isStandardLayout()) return false; 5106 } 5107 5108 // See if this is the last field decl in the record. 5109 const Decl *D = FD; 5110 while ((D = D->getNextDeclInContext())) 5111 if (isa<FieldDecl>(D)) 5112 return false; 5113 return true; 5114} 5115 5116void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr, 5117 const ArraySubscriptExpr *ASE, 5118 bool AllowOnePastEnd, bool IndexNegated) { 5119 IndexExpr = IndexExpr->IgnoreParenImpCasts(); 5120 if (IndexExpr->isValueDependent()) 5121 return; 5122 5123 const Type *EffectiveType = getElementType(BaseExpr); 5124 BaseExpr = BaseExpr->IgnoreParenCasts(); 5125 const ConstantArrayType *ArrayTy = 5126 Context.getAsConstantArrayType(BaseExpr->getType()); 5127 if (!ArrayTy) 5128 return; 5129 5130 llvm::APSInt index; 5131 if (!IndexExpr->EvaluateAsInt(index, Context)) 5132 return; 5133 if (IndexNegated) 5134 index = -index; 5135 5136 const NamedDecl *ND = NULL; 5137 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 5138 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 5139 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 5140 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 5141 5142 if (index.isUnsigned() || !index.isNegative()) { 5143 llvm::APInt size = ArrayTy->getSize(); 5144 if (!size.isStrictlyPositive()) 5145 return; 5146 5147 const Type* BaseType = getElementType(BaseExpr); 5148 if (BaseType != EffectiveType) { 5149 // Make sure we're comparing apples to apples when comparing index to size 5150 uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType); 5151 uint64_t array_typesize = Context.getTypeSize(BaseType); 5152 // Handle ptrarith_typesize being zero, such as when casting to void* 5153 if (!ptrarith_typesize) ptrarith_typesize = 1; 5154 if (ptrarith_typesize != array_typesize) { 5155 // There's a cast to a different size type involved 5156 uint64_t ratio = array_typesize / ptrarith_typesize; 5157 // TODO: Be smarter about handling cases where array_typesize is not a 5158 // multiple of ptrarith_typesize 5159 if (ptrarith_typesize * ratio == array_typesize) 5160 size *= llvm::APInt(size.getBitWidth(), ratio); 5161 } 5162 } 5163 5164 if (size.getBitWidth() > index.getBitWidth()) 5165 index = index.zext(size.getBitWidth()); 5166 else if (size.getBitWidth() < index.getBitWidth()) 5167 size = size.zext(index.getBitWidth()); 5168 5169 // For array subscripting the index must be less than size, but for pointer 5170 // arithmetic also allow the index (offset) to be equal to size since 5171 // computing the next address after the end of the array is legal and 5172 // commonly done e.g. in C++ iterators and range-based for loops. 5173 if (AllowOnePastEnd ? index.ule(size) : index.ult(size)) 5174 return; 5175 5176 // Also don't warn for arrays of size 1 which are members of some 5177 // structure. These are often used to approximate flexible arrays in C89 5178 // code. 5179 if (IsTailPaddedMemberArray(*this, size, ND)) 5180 return; 5181 5182 // Suppress the warning if the subscript expression (as identified by the 5183 // ']' location) and the index expression are both from macro expansions 5184 // within a system header. 5185 if (ASE) { 5186 SourceLocation RBracketLoc = SourceMgr.getSpellingLoc( 5187 ASE->getRBracketLoc()); 5188 if (SourceMgr.isInSystemHeader(RBracketLoc)) { 5189 SourceLocation IndexLoc = SourceMgr.getSpellingLoc( 5190 IndexExpr->getLocStart()); 5191 if (SourceMgr.isFromSameFile(RBracketLoc, IndexLoc)) 5192 return; 5193 } 5194 } 5195 5196 unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds; 5197 if (ASE) 5198 DiagID = diag::warn_array_index_exceeds_bounds; 5199 5200 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 5201 PDiag(DiagID) << index.toString(10, true) 5202 << size.toString(10, true) 5203 << (unsigned)size.getLimitedValue(~0U) 5204 << IndexExpr->getSourceRange()); 5205 } else { 5206 unsigned DiagID = diag::warn_array_index_precedes_bounds; 5207 if (!ASE) { 5208 DiagID = diag::warn_ptr_arith_precedes_bounds; 5209 if (index.isNegative()) index = -index; 5210 } 5211 5212 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 5213 PDiag(DiagID) << index.toString(10, true) 5214 << IndexExpr->getSourceRange()); 5215 } 5216 5217 if (!ND) { 5218 // Try harder to find a NamedDecl to point at in the note. 5219 while (const ArraySubscriptExpr *ASE = 5220 dyn_cast<ArraySubscriptExpr>(BaseExpr)) 5221 BaseExpr = ASE->getBase()->IgnoreParenCasts(); 5222 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 5223 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 5224 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 5225 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 5226 } 5227 5228 if (ND) 5229 DiagRuntimeBehavior(ND->getLocStart(), BaseExpr, 5230 PDiag(diag::note_array_index_out_of_bounds) 5231 << ND->getDeclName()); 5232} 5233 5234void Sema::CheckArrayAccess(const Expr *expr) { 5235 int AllowOnePastEnd = 0; 5236 while (expr) { 5237 expr = expr->IgnoreParenImpCasts(); 5238 switch (expr->getStmtClass()) { 5239 case Stmt::ArraySubscriptExprClass: { 5240 const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr); 5241 CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE, 5242 AllowOnePastEnd > 0); 5243 return; 5244 } 5245 case Stmt::UnaryOperatorClass: { 5246 // Only unwrap the * and & unary operators 5247 const UnaryOperator *UO = cast<UnaryOperator>(expr); 5248 expr = UO->getSubExpr(); 5249 switch (UO->getOpcode()) { 5250 case UO_AddrOf: 5251 AllowOnePastEnd++; 5252 break; 5253 case UO_Deref: 5254 AllowOnePastEnd--; 5255 break; 5256 default: 5257 return; 5258 } 5259 break; 5260 } 5261 case Stmt::ConditionalOperatorClass: { 5262 const ConditionalOperator *cond = cast<ConditionalOperator>(expr); 5263 if (const Expr *lhs = cond->getLHS()) 5264 CheckArrayAccess(lhs); 5265 if (const Expr *rhs = cond->getRHS()) 5266 CheckArrayAccess(rhs); 5267 return; 5268 } 5269 default: 5270 return; 5271 } 5272 } 5273} 5274 5275//===--- CHECK: Objective-C retain cycles ----------------------------------// 5276 5277namespace { 5278 struct RetainCycleOwner { 5279 RetainCycleOwner() : Variable(0), Indirect(false) {} 5280 VarDecl *Variable; 5281 SourceRange Range; 5282 SourceLocation Loc; 5283 bool Indirect; 5284 5285 void setLocsFrom(Expr *e) { 5286 Loc = e->getExprLoc(); 5287 Range = e->getSourceRange(); 5288 } 5289 }; 5290} 5291 5292/// Consider whether capturing the given variable can possibly lead to 5293/// a retain cycle. 5294static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) { 5295 // In ARC, it's captured strongly iff the variable has __strong 5296 // lifetime. In MRR, it's captured strongly if the variable is 5297 // __block and has an appropriate type. 5298 if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 5299 return false; 5300 5301 owner.Variable = var; 5302 owner.setLocsFrom(ref); 5303 return true; 5304} 5305 5306static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) { 5307 while (true) { 5308 e = e->IgnoreParens(); 5309 if (CastExpr *cast = dyn_cast<CastExpr>(e)) { 5310 switch (cast->getCastKind()) { 5311 case CK_BitCast: 5312 case CK_LValueBitCast: 5313 case CK_LValueToRValue: 5314 case CK_ARCReclaimReturnedObject: 5315 e = cast->getSubExpr(); 5316 continue; 5317 5318 default: 5319 return false; 5320 } 5321 } 5322 5323 if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) { 5324 ObjCIvarDecl *ivar = ref->getDecl(); 5325 if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 5326 return false; 5327 5328 // Try to find a retain cycle in the base. 5329 if (!findRetainCycleOwner(S, ref->getBase(), owner)) 5330 return false; 5331 5332 if (ref->isFreeIvar()) owner.setLocsFrom(ref); 5333 owner.Indirect = true; 5334 return true; 5335 } 5336 5337 if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) { 5338 VarDecl *var = dyn_cast<VarDecl>(ref->getDecl()); 5339 if (!var) return false; 5340 return considerVariable(var, ref, owner); 5341 } 5342 5343 if (MemberExpr *member = dyn_cast<MemberExpr>(e)) { 5344 if (member->isArrow()) return false; 5345 5346 // Don't count this as an indirect ownership. 5347 e = member->getBase(); 5348 continue; 5349 } 5350 5351 if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) { 5352 // Only pay attention to pseudo-objects on property references. 5353 ObjCPropertyRefExpr *pre 5354 = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm() 5355 ->IgnoreParens()); 5356 if (!pre) return false; 5357 if (pre->isImplicitProperty()) return false; 5358 ObjCPropertyDecl *property = pre->getExplicitProperty(); 5359 if (!property->isRetaining() && 5360 !(property->getPropertyIvarDecl() && 5361 property->getPropertyIvarDecl()->getType() 5362 .getObjCLifetime() == Qualifiers::OCL_Strong)) 5363 return false; 5364 5365 owner.Indirect = true; 5366 if (pre->isSuperReceiver()) { 5367 owner.Variable = S.getCurMethodDecl()->getSelfDecl(); 5368 if (!owner.Variable) 5369 return false; 5370 owner.Loc = pre->getLocation(); 5371 owner.Range = pre->getSourceRange(); 5372 return true; 5373 } 5374 e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase()) 5375 ->getSourceExpr()); 5376 continue; 5377 } 5378 5379 // Array ivars? 5380 5381 return false; 5382 } 5383} 5384 5385namespace { 5386 struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> { 5387 FindCaptureVisitor(ASTContext &Context, VarDecl *variable) 5388 : EvaluatedExprVisitor<FindCaptureVisitor>(Context), 5389 Variable(variable), Capturer(0) {} 5390 5391 VarDecl *Variable; 5392 Expr *Capturer; 5393 5394 void VisitDeclRefExpr(DeclRefExpr *ref) { 5395 if (ref->getDecl() == Variable && !Capturer) 5396 Capturer = ref; 5397 } 5398 5399 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) { 5400 if (Capturer) return; 5401 Visit(ref->getBase()); 5402 if (Capturer && ref->isFreeIvar()) 5403 Capturer = ref; 5404 } 5405 5406 void VisitBlockExpr(BlockExpr *block) { 5407 // Look inside nested blocks 5408 if (block->getBlockDecl()->capturesVariable(Variable)) 5409 Visit(block->getBlockDecl()->getBody()); 5410 } 5411 5412 void VisitOpaqueValueExpr(OpaqueValueExpr *OVE) { 5413 if (Capturer) return; 5414 if (OVE->getSourceExpr()) 5415 Visit(OVE->getSourceExpr()); 5416 } 5417 }; 5418} 5419 5420/// Check whether the given argument is a block which captures a 5421/// variable. 5422static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) { 5423 assert(owner.Variable && owner.Loc.isValid()); 5424 5425 e = e->IgnoreParenCasts(); 5426 BlockExpr *block = dyn_cast<BlockExpr>(e); 5427 if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable)) 5428 return 0; 5429 5430 FindCaptureVisitor visitor(S.Context, owner.Variable); 5431 visitor.Visit(block->getBlockDecl()->getBody()); 5432 return visitor.Capturer; 5433} 5434 5435static void diagnoseRetainCycle(Sema &S, Expr *capturer, 5436 RetainCycleOwner &owner) { 5437 assert(capturer); 5438 assert(owner.Variable && owner.Loc.isValid()); 5439 5440 S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle) 5441 << owner.Variable << capturer->getSourceRange(); 5442 S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner) 5443 << owner.Indirect << owner.Range; 5444} 5445 5446/// Check for a keyword selector that starts with the word 'add' or 5447/// 'set'. 5448static bool isSetterLikeSelector(Selector sel) { 5449 if (sel.isUnarySelector()) return false; 5450 5451 StringRef str = sel.getNameForSlot(0); 5452 while (!str.empty() && str.front() == '_') str = str.substr(1); 5453 if (str.startswith("set")) 5454 str = str.substr(3); 5455 else if (str.startswith("add")) { 5456 // Specially whitelist 'addOperationWithBlock:'. 5457 if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock")) 5458 return false; 5459 str = str.substr(3); 5460 } 5461 else 5462 return false; 5463 5464 if (str.empty()) return true; 5465 return !islower(str.front()); 5466} 5467 5468/// Check a message send to see if it's likely to cause a retain cycle. 5469void Sema::checkRetainCycles(ObjCMessageExpr *msg) { 5470 // Only check instance methods whose selector looks like a setter. 5471 if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector())) 5472 return; 5473 5474 // Try to find a variable that the receiver is strongly owned by. 5475 RetainCycleOwner owner; 5476 if (msg->getReceiverKind() == ObjCMessageExpr::Instance) { 5477 if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner)) 5478 return; 5479 } else { 5480 assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance); 5481 owner.Variable = getCurMethodDecl()->getSelfDecl(); 5482 owner.Loc = msg->getSuperLoc(); 5483 owner.Range = msg->getSuperLoc(); 5484 } 5485 5486 // Check whether the receiver is captured by any of the arguments. 5487 for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i) 5488 if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner)) 5489 return diagnoseRetainCycle(*this, capturer, owner); 5490} 5491 5492/// Check a property assign to see if it's likely to cause a retain cycle. 5493void Sema::checkRetainCycles(Expr *receiver, Expr *argument) { 5494 RetainCycleOwner owner; 5495 if (!findRetainCycleOwner(*this, receiver, owner)) 5496 return; 5497 5498 if (Expr *capturer = findCapturingExpr(*this, argument, owner)) 5499 diagnoseRetainCycle(*this, capturer, owner); 5500} 5501 5502bool Sema::checkUnsafeAssigns(SourceLocation Loc, 5503 QualType LHS, Expr *RHS) { 5504 Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime(); 5505 if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone) 5506 return false; 5507 // strip off any implicit cast added to get to the one arc-specific 5508 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 5509 if (cast->getCastKind() == CK_ARCConsumeObject) { 5510 Diag(Loc, diag::warn_arc_retained_assign) 5511 << (LT == Qualifiers::OCL_ExplicitNone) << 1 5512 << RHS->getSourceRange(); 5513 return true; 5514 } 5515 RHS = cast->getSubExpr(); 5516 } 5517 return false; 5518} 5519 5520void Sema::checkUnsafeExprAssigns(SourceLocation Loc, 5521 Expr *LHS, Expr *RHS) { 5522 QualType LHSType; 5523 // PropertyRef on LHS type need be directly obtained from 5524 // its declaration as it has a PsuedoType. 5525 ObjCPropertyRefExpr *PRE 5526 = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens()); 5527 if (PRE && !PRE->isImplicitProperty()) { 5528 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 5529 if (PD) 5530 LHSType = PD->getType(); 5531 } 5532 5533 if (LHSType.isNull()) 5534 LHSType = LHS->getType(); 5535 if (checkUnsafeAssigns(Loc, LHSType, RHS)) 5536 return; 5537 Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime(); 5538 // FIXME. Check for other life times. 5539 if (LT != Qualifiers::OCL_None) 5540 return; 5541 5542 if (PRE) { 5543 if (PRE->isImplicitProperty()) 5544 return; 5545 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 5546 if (!PD) 5547 return; 5548 5549 unsigned Attributes = PD->getPropertyAttributes(); 5550 if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) { 5551 // when 'assign' attribute was not explicitly specified 5552 // by user, ignore it and rely on property type itself 5553 // for lifetime info. 5554 unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten(); 5555 if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) && 5556 LHSType->isObjCRetainableType()) 5557 return; 5558 5559 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 5560 if (cast->getCastKind() == CK_ARCConsumeObject) { 5561 Diag(Loc, diag::warn_arc_retained_property_assign) 5562 << RHS->getSourceRange(); 5563 return; 5564 } 5565 RHS = cast->getSubExpr(); 5566 } 5567 } 5568 else if (Attributes & ObjCPropertyDecl::OBJC_PR_weak) { 5569 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 5570 if (cast->getCastKind() == CK_ARCConsumeObject) { 5571 Diag(Loc, diag::warn_arc_retained_assign) 5572 << 0 << 0<< RHS->getSourceRange(); 5573 return; 5574 } 5575 RHS = cast->getSubExpr(); 5576 } 5577 } 5578 } 5579} 5580 5581//===--- CHECK: Empty statement body (-Wempty-body) ---------------------===// 5582 5583namespace { 5584bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr, 5585 SourceLocation StmtLoc, 5586 const NullStmt *Body) { 5587 // Do not warn if the body is a macro that expands to nothing, e.g: 5588 // 5589 // #define CALL(x) 5590 // if (condition) 5591 // CALL(0); 5592 // 5593 if (Body->hasLeadingEmptyMacro()) 5594 return false; 5595 5596 // Get line numbers of statement and body. 5597 bool StmtLineInvalid; 5598 unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc, 5599 &StmtLineInvalid); 5600 if (StmtLineInvalid) 5601 return false; 5602 5603 bool BodyLineInvalid; 5604 unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(), 5605 &BodyLineInvalid); 5606 if (BodyLineInvalid) 5607 return false; 5608 5609 // Warn if null statement and body are on the same line. 5610 if (StmtLine != BodyLine) 5611 return false; 5612 5613 return true; 5614} 5615} // Unnamed namespace 5616 5617void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc, 5618 const Stmt *Body, 5619 unsigned DiagID) { 5620 // Since this is a syntactic check, don't emit diagnostic for template 5621 // instantiations, this just adds noise. 5622 if (CurrentInstantiationScope) 5623 return; 5624 5625 // The body should be a null statement. 5626 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 5627 if (!NBody) 5628 return; 5629 5630 // Do the usual checks. 5631 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 5632 return; 5633 5634 Diag(NBody->getSemiLoc(), DiagID); 5635 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 5636} 5637 5638void Sema::DiagnoseEmptyLoopBody(const Stmt *S, 5639 const Stmt *PossibleBody) { 5640 assert(!CurrentInstantiationScope); // Ensured by caller 5641 5642 SourceLocation StmtLoc; 5643 const Stmt *Body; 5644 unsigned DiagID; 5645 if (const ForStmt *FS = dyn_cast<ForStmt>(S)) { 5646 StmtLoc = FS->getRParenLoc(); 5647 Body = FS->getBody(); 5648 DiagID = diag::warn_empty_for_body; 5649 } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) { 5650 StmtLoc = WS->getCond()->getSourceRange().getEnd(); 5651 Body = WS->getBody(); 5652 DiagID = diag::warn_empty_while_body; 5653 } else 5654 return; // Neither `for' nor `while'. 5655 5656 // The body should be a null statement. 5657 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 5658 if (!NBody) 5659 return; 5660 5661 // Skip expensive checks if diagnostic is disabled. 5662 if (Diags.getDiagnosticLevel(DiagID, NBody->getSemiLoc()) == 5663 DiagnosticsEngine::Ignored) 5664 return; 5665 5666 // Do the usual checks. 5667 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 5668 return; 5669 5670 // `for(...);' and `while(...);' are popular idioms, so in order to keep 5671 // noise level low, emit diagnostics only if for/while is followed by a 5672 // CompoundStmt, e.g.: 5673 // for (int i = 0; i < n; i++); 5674 // { 5675 // a(i); 5676 // } 5677 // or if for/while is followed by a statement with more indentation 5678 // than for/while itself: 5679 // for (int i = 0; i < n; i++); 5680 // a(i); 5681 bool ProbableTypo = isa<CompoundStmt>(PossibleBody); 5682 if (!ProbableTypo) { 5683 bool BodyColInvalid; 5684 unsigned BodyCol = SourceMgr.getPresumedColumnNumber( 5685 PossibleBody->getLocStart(), 5686 &BodyColInvalid); 5687 if (BodyColInvalid) 5688 return; 5689 5690 bool StmtColInvalid; 5691 unsigned StmtCol = SourceMgr.getPresumedColumnNumber( 5692 S->getLocStart(), 5693 &StmtColInvalid); 5694 if (StmtColInvalid) 5695 return; 5696 5697 if (BodyCol > StmtCol) 5698 ProbableTypo = true; 5699 } 5700 5701 if (ProbableTypo) { 5702 Diag(NBody->getSemiLoc(), DiagID); 5703 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 5704 } 5705} 5706 5707//===--- Layout compatibility ----------------------------------------------// 5708 5709namespace { 5710 5711bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2); 5712 5713/// \brief Check if two enumeration types are layout-compatible. 5714bool isLayoutCompatible(ASTContext &C, EnumDecl *ED1, EnumDecl *ED2) { 5715 // C++11 [dcl.enum] p8: 5716 // Two enumeration types are layout-compatible if they have the same 5717 // underlying type. 5718 return ED1->isComplete() && ED2->isComplete() && 5719 C.hasSameType(ED1->getIntegerType(), ED2->getIntegerType()); 5720} 5721 5722/// \brief Check if two fields are layout-compatible. 5723bool isLayoutCompatible(ASTContext &C, FieldDecl *Field1, FieldDecl *Field2) { 5724 if (!isLayoutCompatible(C, Field1->getType(), Field2->getType())) 5725 return false; 5726 5727 if (Field1->isBitField() != Field2->isBitField()) 5728 return false; 5729 5730 if (Field1->isBitField()) { 5731 // Make sure that the bit-fields are the same length. 5732 unsigned Bits1 = Field1->getBitWidthValue(C); 5733 unsigned Bits2 = Field2->getBitWidthValue(C); 5734 5735 if (Bits1 != Bits2) 5736 return false; 5737 } 5738 5739 return true; 5740} 5741 5742/// \brief Check if two standard-layout structs are layout-compatible. 5743/// (C++11 [class.mem] p17) 5744bool isLayoutCompatibleStruct(ASTContext &C, 5745 RecordDecl *RD1, 5746 RecordDecl *RD2) { 5747 // If both records are C++ classes, check that base classes match. 5748 if (const CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(RD1)) { 5749 // If one of records is a CXXRecordDecl we are in C++ mode, 5750 // thus the other one is a CXXRecordDecl, too. 5751 const CXXRecordDecl *D2CXX = cast<CXXRecordDecl>(RD2); 5752 // Check number of base classes. 5753 if (D1CXX->getNumBases() != D2CXX->getNumBases()) 5754 return false; 5755 5756 // Check the base classes. 5757 for (CXXRecordDecl::base_class_const_iterator 5758 Base1 = D1CXX->bases_begin(), 5759 BaseEnd1 = D1CXX->bases_end(), 5760 Base2 = D2CXX->bases_begin(); 5761 Base1 != BaseEnd1; 5762 ++Base1, ++Base2) { 5763 if (!isLayoutCompatible(C, Base1->getType(), Base2->getType())) 5764 return false; 5765 } 5766 } else if (const CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(RD2)) { 5767 // If only RD2 is a C++ class, it should have zero base classes. 5768 if (D2CXX->getNumBases() > 0) 5769 return false; 5770 } 5771 5772 // Check the fields. 5773 RecordDecl::field_iterator Field2 = RD2->field_begin(), 5774 Field2End = RD2->field_end(), 5775 Field1 = RD1->field_begin(), 5776 Field1End = RD1->field_end(); 5777 for ( ; Field1 != Field1End && Field2 != Field2End; ++Field1, ++Field2) { 5778 if (!isLayoutCompatible(C, *Field1, *Field2)) 5779 return false; 5780 } 5781 if (Field1 != Field1End || Field2 != Field2End) 5782 return false; 5783 5784 return true; 5785} 5786 5787/// \brief Check if two standard-layout unions are layout-compatible. 5788/// (C++11 [class.mem] p18) 5789bool isLayoutCompatibleUnion(ASTContext &C, 5790 RecordDecl *RD1, 5791 RecordDecl *RD2) { 5792 llvm::SmallPtrSet<FieldDecl *, 8> UnmatchedFields; 5793 for (RecordDecl::field_iterator Field2 = RD2->field_begin(), 5794 Field2End = RD2->field_end(); 5795 Field2 != Field2End; ++Field2) { 5796 UnmatchedFields.insert(*Field2); 5797 } 5798 5799 for (RecordDecl::field_iterator Field1 = RD1->field_begin(), 5800 Field1End = RD1->field_end(); 5801 Field1 != Field1End; ++Field1) { 5802 llvm::SmallPtrSet<FieldDecl *, 8>::iterator 5803 I = UnmatchedFields.begin(), 5804 E = UnmatchedFields.end(); 5805 5806 for ( ; I != E; ++I) { 5807 if (isLayoutCompatible(C, *Field1, *I)) { 5808 bool Result = UnmatchedFields.erase(*I); 5809 (void) Result; 5810 assert(Result); 5811 break; 5812 } 5813 } 5814 if (I == E) 5815 return false; 5816 } 5817 5818 return UnmatchedFields.empty(); 5819} 5820 5821bool isLayoutCompatible(ASTContext &C, RecordDecl *RD1, RecordDecl *RD2) { 5822 if (RD1->isUnion() != RD2->isUnion()) 5823 return false; 5824 5825 if (RD1->isUnion()) 5826 return isLayoutCompatibleUnion(C, RD1, RD2); 5827 else 5828 return isLayoutCompatibleStruct(C, RD1, RD2); 5829} 5830 5831/// \brief Check if two types are layout-compatible in C++11 sense. 5832bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2) { 5833 if (T1.isNull() || T2.isNull()) 5834 return false; 5835 5836 // C++11 [basic.types] p11: 5837 // If two types T1 and T2 are the same type, then T1 and T2 are 5838 // layout-compatible types. 5839 if (C.hasSameType(T1, T2)) 5840 return true; 5841 5842 T1 = T1.getCanonicalType().getUnqualifiedType(); 5843 T2 = T2.getCanonicalType().getUnqualifiedType(); 5844 5845 const Type::TypeClass TC1 = T1->getTypeClass(); 5846 const Type::TypeClass TC2 = T2->getTypeClass(); 5847 5848 if (TC1 != TC2) 5849 return false; 5850 5851 if (TC1 == Type::Enum) { 5852 return isLayoutCompatible(C, 5853 cast<EnumType>(T1)->getDecl(), 5854 cast<EnumType>(T2)->getDecl()); 5855 } else if (TC1 == Type::Record) { 5856 if (!T1->isStandardLayoutType() || !T2->isStandardLayoutType()) 5857 return false; 5858 5859 return isLayoutCompatible(C, 5860 cast<RecordType>(T1)->getDecl(), 5861 cast<RecordType>(T2)->getDecl()); 5862 } 5863 5864 return false; 5865} 5866} 5867 5868//===--- CHECK: pointer_with_type_tag attribute: datatypes should match ----// 5869 5870namespace { 5871/// \brief Given a type tag expression find the type tag itself. 5872/// 5873/// \param TypeExpr Type tag expression, as it appears in user's code. 5874/// 5875/// \param VD Declaration of an identifier that appears in a type tag. 5876/// 5877/// \param MagicValue Type tag magic value. 5878bool FindTypeTagExpr(const Expr *TypeExpr, const ASTContext &Ctx, 5879 const ValueDecl **VD, uint64_t *MagicValue) { 5880 while(true) { 5881 if (!TypeExpr) 5882 return false; 5883 5884 TypeExpr = TypeExpr->IgnoreParenImpCasts()->IgnoreParenCasts(); 5885 5886 switch (TypeExpr->getStmtClass()) { 5887 case Stmt::UnaryOperatorClass: { 5888 const UnaryOperator *UO = cast<UnaryOperator>(TypeExpr); 5889 if (UO->getOpcode() == UO_AddrOf || UO->getOpcode() == UO_Deref) { 5890 TypeExpr = UO->getSubExpr(); 5891 continue; 5892 } 5893 return false; 5894 } 5895 5896 case Stmt::DeclRefExprClass: { 5897 const DeclRefExpr *DRE = cast<DeclRefExpr>(TypeExpr); 5898 *VD = DRE->getDecl(); 5899 return true; 5900 } 5901 5902 case Stmt::IntegerLiteralClass: { 5903 const IntegerLiteral *IL = cast<IntegerLiteral>(TypeExpr); 5904 llvm::APInt MagicValueAPInt = IL->getValue(); 5905 if (MagicValueAPInt.getActiveBits() <= 64) { 5906 *MagicValue = MagicValueAPInt.getZExtValue(); 5907 return true; 5908 } else 5909 return false; 5910 } 5911 5912 case Stmt::BinaryConditionalOperatorClass: 5913 case Stmt::ConditionalOperatorClass: { 5914 const AbstractConditionalOperator *ACO = 5915 cast<AbstractConditionalOperator>(TypeExpr); 5916 bool Result; 5917 if (ACO->getCond()->EvaluateAsBooleanCondition(Result, Ctx)) { 5918 if (Result) 5919 TypeExpr = ACO->getTrueExpr(); 5920 else 5921 TypeExpr = ACO->getFalseExpr(); 5922 continue; 5923 } 5924 return false; 5925 } 5926 5927 case Stmt::BinaryOperatorClass: { 5928 const BinaryOperator *BO = cast<BinaryOperator>(TypeExpr); 5929 if (BO->getOpcode() == BO_Comma) { 5930 TypeExpr = BO->getRHS(); 5931 continue; 5932 } 5933 return false; 5934 } 5935 5936 default: 5937 return false; 5938 } 5939 } 5940} 5941 5942/// \brief Retrieve the C type corresponding to type tag TypeExpr. 5943/// 5944/// \param TypeExpr Expression that specifies a type tag. 5945/// 5946/// \param MagicValues Registered magic values. 5947/// 5948/// \param FoundWrongKind Set to true if a type tag was found, but of a wrong 5949/// kind. 5950/// 5951/// \param TypeInfo Information about the corresponding C type. 5952/// 5953/// \returns true if the corresponding C type was found. 5954bool GetMatchingCType( 5955 const IdentifierInfo *ArgumentKind, 5956 const Expr *TypeExpr, const ASTContext &Ctx, 5957 const llvm::DenseMap<Sema::TypeTagMagicValue, 5958 Sema::TypeTagData> *MagicValues, 5959 bool &FoundWrongKind, 5960 Sema::TypeTagData &TypeInfo) { 5961 FoundWrongKind = false; 5962 5963 // Variable declaration that has type_tag_for_datatype attribute. 5964 const ValueDecl *VD = NULL; 5965 5966 uint64_t MagicValue; 5967 5968 if (!FindTypeTagExpr(TypeExpr, Ctx, &VD, &MagicValue)) 5969 return false; 5970 5971 if (VD) { 5972 for (specific_attr_iterator<TypeTagForDatatypeAttr> 5973 I = VD->specific_attr_begin<TypeTagForDatatypeAttr>(), 5974 E = VD->specific_attr_end<TypeTagForDatatypeAttr>(); 5975 I != E; ++I) { 5976 if (I->getArgumentKind() != ArgumentKind) { 5977 FoundWrongKind = true; 5978 return false; 5979 } 5980 TypeInfo.Type = I->getMatchingCType(); 5981 TypeInfo.LayoutCompatible = I->getLayoutCompatible(); 5982 TypeInfo.MustBeNull = I->getMustBeNull(); 5983 return true; 5984 } 5985 return false; 5986 } 5987 5988 if (!MagicValues) 5989 return false; 5990 5991 llvm::DenseMap<Sema::TypeTagMagicValue, 5992 Sema::TypeTagData>::const_iterator I = 5993 MagicValues->find(std::make_pair(ArgumentKind, MagicValue)); 5994 if (I == MagicValues->end()) 5995 return false; 5996 5997 TypeInfo = I->second; 5998 return true; 5999} 6000} // unnamed namespace 6001 6002void Sema::RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind, 6003 uint64_t MagicValue, QualType Type, 6004 bool LayoutCompatible, 6005 bool MustBeNull) { 6006 if (!TypeTagForDatatypeMagicValues) 6007 TypeTagForDatatypeMagicValues.reset( 6008 new llvm::DenseMap<TypeTagMagicValue, TypeTagData>); 6009 6010 TypeTagMagicValue Magic(ArgumentKind, MagicValue); 6011 (*TypeTagForDatatypeMagicValues)[Magic] = 6012 TypeTagData(Type, LayoutCompatible, MustBeNull); 6013} 6014 6015namespace { 6016bool IsSameCharType(QualType T1, QualType T2) { 6017 const BuiltinType *BT1 = T1->getAs<BuiltinType>(); 6018 if (!BT1) 6019 return false; 6020 6021 const BuiltinType *BT2 = T2->getAs<BuiltinType>(); 6022 if (!BT2) 6023 return false; 6024 6025 BuiltinType::Kind T1Kind = BT1->getKind(); 6026 BuiltinType::Kind T2Kind = BT2->getKind(); 6027 6028 return (T1Kind == BuiltinType::SChar && T2Kind == BuiltinType::Char_S) || 6029 (T1Kind == BuiltinType::UChar && T2Kind == BuiltinType::Char_U) || 6030 (T1Kind == BuiltinType::Char_U && T2Kind == BuiltinType::UChar) || 6031 (T1Kind == BuiltinType::Char_S && T2Kind == BuiltinType::SChar); 6032} 6033} // unnamed namespace 6034 6035void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr, 6036 const Expr * const *ExprArgs) { 6037 const IdentifierInfo *ArgumentKind = Attr->getArgumentKind(); 6038 bool IsPointerAttr = Attr->getIsPointer(); 6039 6040 const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()]; 6041 bool FoundWrongKind; 6042 TypeTagData TypeInfo; 6043 if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context, 6044 TypeTagForDatatypeMagicValues.get(), 6045 FoundWrongKind, TypeInfo)) { 6046 if (FoundWrongKind) 6047 Diag(TypeTagExpr->getExprLoc(), 6048 diag::warn_type_tag_for_datatype_wrong_kind) 6049 << TypeTagExpr->getSourceRange(); 6050 return; 6051 } 6052 6053 const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()]; 6054 if (IsPointerAttr) { 6055 // Skip implicit cast of pointer to `void *' (as a function argument). 6056 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr)) 6057 if (ICE->getType()->isVoidPointerType()) 6058 ArgumentExpr = ICE->getSubExpr(); 6059 } 6060 QualType ArgumentType = ArgumentExpr->getType(); 6061 6062 // Passing a `void*' pointer shouldn't trigger a warning. 6063 if (IsPointerAttr && ArgumentType->isVoidPointerType()) 6064 return; 6065 6066 if (TypeInfo.MustBeNull) { 6067 // Type tag with matching void type requires a null pointer. 6068 if (!ArgumentExpr->isNullPointerConstant(Context, 6069 Expr::NPC_ValueDependentIsNotNull)) { 6070 Diag(ArgumentExpr->getExprLoc(), 6071 diag::warn_type_safety_null_pointer_required) 6072 << ArgumentKind->getName() 6073 << ArgumentExpr->getSourceRange() 6074 << TypeTagExpr->getSourceRange(); 6075 } 6076 return; 6077 } 6078 6079 QualType RequiredType = TypeInfo.Type; 6080 if (IsPointerAttr) 6081 RequiredType = Context.getPointerType(RequiredType); 6082 6083 bool mismatch = false; 6084 if (!TypeInfo.LayoutCompatible) { 6085 mismatch = !Context.hasSameType(ArgumentType, RequiredType); 6086 6087 // C++11 [basic.fundamental] p1: 6088 // Plain char, signed char, and unsigned char are three distinct types. 6089 // 6090 // But we treat plain `char' as equivalent to `signed char' or `unsigned 6091 // char' depending on the current char signedness mode. 6092 if (mismatch) 6093 if ((IsPointerAttr && IsSameCharType(ArgumentType->getPointeeType(), 6094 RequiredType->getPointeeType())) || 6095 (!IsPointerAttr && IsSameCharType(ArgumentType, RequiredType))) 6096 mismatch = false; 6097 } else 6098 if (IsPointerAttr) 6099 mismatch = !isLayoutCompatible(Context, 6100 ArgumentType->getPointeeType(), 6101 RequiredType->getPointeeType()); 6102 else 6103 mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType); 6104 6105 if (mismatch) 6106 Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch) 6107 << ArgumentType << ArgumentKind->getName() 6108 << TypeInfo.LayoutCompatible << RequiredType 6109 << ArgumentExpr->getSourceRange() 6110 << TypeTagExpr->getSourceRange(); 6111} 6112 6113