SemaChecking.cpp revision 8f50b24c8b17368f68c2e71240d487dde53f6da8
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 if (CurContext->isDependentContext()) 499 return; 500 501 // Printf and scanf checking. 502 bool HandledFormatString = false; 503 for (specific_attr_iterator<FormatAttr> 504 I = FDecl->specific_attr_begin<FormatAttr>(), 505 E = FDecl->specific_attr_end<FormatAttr>(); I != E ; ++I) 506 if (CheckFormatArguments(*I, Args, NumArgs, IsMemberFunction, CallType, 507 Loc, Range)) 508 HandledFormatString = true; 509 510 // Refuse POD arguments that weren't caught by the format string 511 // checks above. 512 if (!HandledFormatString && CallType != VariadicDoesNotApply) 513 for (unsigned ArgIdx = NumProtoArgs; ArgIdx < NumArgs; ++ArgIdx) { 514 // Args[ArgIdx] can be null in malformed code. 515 if (Expr *Arg = Args[ArgIdx]) 516 variadicArgumentPODCheck(Arg, CallType); 517 } 518 519 for (specific_attr_iterator<NonNullAttr> 520 I = FDecl->specific_attr_begin<NonNullAttr>(), 521 E = FDecl->specific_attr_end<NonNullAttr>(); I != E; ++I) 522 CheckNonNullArguments(*I, Args, Loc); 523 524 // Type safety checking. 525 for (specific_attr_iterator<ArgumentWithTypeTagAttr> 526 i = FDecl->specific_attr_begin<ArgumentWithTypeTagAttr>(), 527 e = FDecl->specific_attr_end<ArgumentWithTypeTagAttr>(); i != e; ++i) { 528 CheckArgumentWithTypeTag(*i, Args); 529 } 530} 531 532/// CheckConstructorCall - Check a constructor call for correctness and safety 533/// properties not enforced by the C type system. 534void Sema::CheckConstructorCall(FunctionDecl *FDecl, Expr **Args, 535 unsigned NumArgs, 536 const FunctionProtoType *Proto, 537 SourceLocation Loc) { 538 VariadicCallType CallType = 539 Proto->isVariadic() ? VariadicConstructor : VariadicDoesNotApply; 540 checkCall(FDecl, Args, NumArgs, Proto->getNumArgs(), 541 /*IsMemberFunction=*/true, Loc, SourceRange(), CallType); 542} 543 544/// CheckFunctionCall - Check a direct function call for various correctness 545/// and safety properties not strictly enforced by the C type system. 546bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall, 547 const FunctionProtoType *Proto) { 548 bool IsMemberOperatorCall = isa<CXXOperatorCallExpr>(TheCall) && 549 isa<CXXMethodDecl>(FDecl); 550 bool IsMemberFunction = isa<CXXMemberCallExpr>(TheCall) || 551 IsMemberOperatorCall; 552 VariadicCallType CallType = getVariadicCallType(FDecl, Proto, 553 TheCall->getCallee()); 554 unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0; 555 Expr** Args = TheCall->getArgs(); 556 unsigned NumArgs = TheCall->getNumArgs(); 557 if (IsMemberOperatorCall) { 558 // If this is a call to a member operator, hide the first argument 559 // from checkCall. 560 // FIXME: Our choice of AST representation here is less than ideal. 561 ++Args; 562 --NumArgs; 563 } 564 checkCall(FDecl, Args, NumArgs, NumProtoArgs, 565 IsMemberFunction, TheCall->getRParenLoc(), 566 TheCall->getCallee()->getSourceRange(), CallType); 567 568 IdentifierInfo *FnInfo = FDecl->getIdentifier(); 569 // None of the checks below are needed for functions that don't have 570 // simple names (e.g., C++ conversion functions). 571 if (!FnInfo) 572 return false; 573 574 unsigned CMId = FDecl->getMemoryFunctionKind(); 575 if (CMId == 0) 576 return false; 577 578 // Handle memory setting and copying functions. 579 if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat) 580 CheckStrlcpycatArguments(TheCall, FnInfo); 581 else if (CMId == Builtin::BIstrncat) 582 CheckStrncatArguments(TheCall, FnInfo); 583 else 584 CheckMemaccessArguments(TheCall, CMId, FnInfo); 585 586 return false; 587} 588 589bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac, 590 Expr **Args, unsigned NumArgs) { 591 VariadicCallType CallType = 592 Method->isVariadic() ? VariadicMethod : VariadicDoesNotApply; 593 594 checkCall(Method, Args, NumArgs, Method->param_size(), 595 /*IsMemberFunction=*/false, 596 lbrac, Method->getSourceRange(), CallType); 597 598 return false; 599} 600 601bool Sema::CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall, 602 const FunctionProtoType *Proto) { 603 const VarDecl *V = dyn_cast<VarDecl>(NDecl); 604 if (!V) 605 return false; 606 607 QualType Ty = V->getType(); 608 if (!Ty->isBlockPointerType()) 609 return false; 610 611 VariadicCallType CallType = 612 Proto && Proto->isVariadic() ? VariadicBlock : VariadicDoesNotApply ; 613 unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0; 614 615 checkCall(NDecl, TheCall->getArgs(), TheCall->getNumArgs(), 616 NumProtoArgs, /*IsMemberFunction=*/false, 617 TheCall->getRParenLoc(), 618 TheCall->getCallee()->getSourceRange(), CallType); 619 620 return false; 621} 622 623ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult, 624 AtomicExpr::AtomicOp Op) { 625 CallExpr *TheCall = cast<CallExpr>(TheCallResult.get()); 626 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 627 628 // All these operations take one of the following forms: 629 enum { 630 // C __c11_atomic_init(A *, C) 631 Init, 632 // C __c11_atomic_load(A *, int) 633 Load, 634 // void __atomic_load(A *, CP, int) 635 Copy, 636 // C __c11_atomic_add(A *, M, int) 637 Arithmetic, 638 // C __atomic_exchange_n(A *, CP, int) 639 Xchg, 640 // void __atomic_exchange(A *, C *, CP, int) 641 GNUXchg, 642 // bool __c11_atomic_compare_exchange_strong(A *, C *, CP, int, int) 643 C11CmpXchg, 644 // bool __atomic_compare_exchange(A *, C *, CP, bool, int, int) 645 GNUCmpXchg 646 } Form = Init; 647 const unsigned NumArgs[] = { 2, 2, 3, 3, 3, 4, 5, 6 }; 648 const unsigned NumVals[] = { 1, 0, 1, 1, 1, 2, 2, 3 }; 649 // where: 650 // C is an appropriate type, 651 // A is volatile _Atomic(C) for __c11 builtins and is C for GNU builtins, 652 // CP is C for __c11 builtins and GNU _n builtins and is C * otherwise, 653 // M is C if C is an integer, and ptrdiff_t if C is a pointer, and 654 // the int parameters are for orderings. 655 656 assert(AtomicExpr::AO__c11_atomic_init == 0 && 657 AtomicExpr::AO__c11_atomic_fetch_xor + 1 == AtomicExpr::AO__atomic_load 658 && "need to update code for modified C11 atomics"); 659 bool IsC11 = Op >= AtomicExpr::AO__c11_atomic_init && 660 Op <= AtomicExpr::AO__c11_atomic_fetch_xor; 661 bool IsN = Op == AtomicExpr::AO__atomic_load_n || 662 Op == AtomicExpr::AO__atomic_store_n || 663 Op == AtomicExpr::AO__atomic_exchange_n || 664 Op == AtomicExpr::AO__atomic_compare_exchange_n; 665 bool IsAddSub = false; 666 667 switch (Op) { 668 case AtomicExpr::AO__c11_atomic_init: 669 Form = Init; 670 break; 671 672 case AtomicExpr::AO__c11_atomic_load: 673 case AtomicExpr::AO__atomic_load_n: 674 Form = Load; 675 break; 676 677 case AtomicExpr::AO__c11_atomic_store: 678 case AtomicExpr::AO__atomic_load: 679 case AtomicExpr::AO__atomic_store: 680 case AtomicExpr::AO__atomic_store_n: 681 Form = Copy; 682 break; 683 684 case AtomicExpr::AO__c11_atomic_fetch_add: 685 case AtomicExpr::AO__c11_atomic_fetch_sub: 686 case AtomicExpr::AO__atomic_fetch_add: 687 case AtomicExpr::AO__atomic_fetch_sub: 688 case AtomicExpr::AO__atomic_add_fetch: 689 case AtomicExpr::AO__atomic_sub_fetch: 690 IsAddSub = true; 691 // Fall through. 692 case AtomicExpr::AO__c11_atomic_fetch_and: 693 case AtomicExpr::AO__c11_atomic_fetch_or: 694 case AtomicExpr::AO__c11_atomic_fetch_xor: 695 case AtomicExpr::AO__atomic_fetch_and: 696 case AtomicExpr::AO__atomic_fetch_or: 697 case AtomicExpr::AO__atomic_fetch_xor: 698 case AtomicExpr::AO__atomic_fetch_nand: 699 case AtomicExpr::AO__atomic_and_fetch: 700 case AtomicExpr::AO__atomic_or_fetch: 701 case AtomicExpr::AO__atomic_xor_fetch: 702 case AtomicExpr::AO__atomic_nand_fetch: 703 Form = Arithmetic; 704 break; 705 706 case AtomicExpr::AO__c11_atomic_exchange: 707 case AtomicExpr::AO__atomic_exchange_n: 708 Form = Xchg; 709 break; 710 711 case AtomicExpr::AO__atomic_exchange: 712 Form = GNUXchg; 713 break; 714 715 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 716 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 717 Form = C11CmpXchg; 718 break; 719 720 case AtomicExpr::AO__atomic_compare_exchange: 721 case AtomicExpr::AO__atomic_compare_exchange_n: 722 Form = GNUCmpXchg; 723 break; 724 } 725 726 // Check we have the right number of arguments. 727 if (TheCall->getNumArgs() < NumArgs[Form]) { 728 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 729 << 0 << NumArgs[Form] << TheCall->getNumArgs() 730 << TheCall->getCallee()->getSourceRange(); 731 return ExprError(); 732 } else if (TheCall->getNumArgs() > NumArgs[Form]) { 733 Diag(TheCall->getArg(NumArgs[Form])->getLocStart(), 734 diag::err_typecheck_call_too_many_args) 735 << 0 << NumArgs[Form] << TheCall->getNumArgs() 736 << TheCall->getCallee()->getSourceRange(); 737 return ExprError(); 738 } 739 740 // Inspect the first argument of the atomic operation. 741 Expr *Ptr = TheCall->getArg(0); 742 Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get(); 743 const PointerType *pointerType = Ptr->getType()->getAs<PointerType>(); 744 if (!pointerType) { 745 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 746 << Ptr->getType() << Ptr->getSourceRange(); 747 return ExprError(); 748 } 749 750 // For a __c11 builtin, this should be a pointer to an _Atomic type. 751 QualType AtomTy = pointerType->getPointeeType(); // 'A' 752 QualType ValType = AtomTy; // 'C' 753 if (IsC11) { 754 if (!AtomTy->isAtomicType()) { 755 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic) 756 << Ptr->getType() << Ptr->getSourceRange(); 757 return ExprError(); 758 } 759 if (AtomTy.isConstQualified()) { 760 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_atomic) 761 << Ptr->getType() << Ptr->getSourceRange(); 762 return ExprError(); 763 } 764 ValType = AtomTy->getAs<AtomicType>()->getValueType(); 765 } 766 767 // For an arithmetic operation, the implied arithmetic must be well-formed. 768 if (Form == Arithmetic) { 769 // gcc does not enforce these rules for GNU atomics, but we do so for sanity. 770 if (IsAddSub && !ValType->isIntegerType() && !ValType->isPointerType()) { 771 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 772 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 773 return ExprError(); 774 } 775 if (!IsAddSub && !ValType->isIntegerType()) { 776 Diag(DRE->getLocStart(), diag::err_atomic_op_bitwise_needs_atomic_int) 777 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 778 return ExprError(); 779 } 780 } else if (IsN && !ValType->isIntegerType() && !ValType->isPointerType()) { 781 // For __atomic_*_n operations, the value type must be a scalar integral or 782 // pointer type which is 1, 2, 4, 8 or 16 bytes in length. 783 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 784 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 785 return ExprError(); 786 } 787 788 if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context)) { 789 // For GNU atomics, require a trivially-copyable type. This is not part of 790 // the GNU atomics specification, but we enforce it for sanity. 791 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_trivial_copy) 792 << Ptr->getType() << Ptr->getSourceRange(); 793 return ExprError(); 794 } 795 796 // FIXME: For any builtin other than a load, the ValType must not be 797 // const-qualified. 798 799 switch (ValType.getObjCLifetime()) { 800 case Qualifiers::OCL_None: 801 case Qualifiers::OCL_ExplicitNone: 802 // okay 803 break; 804 805 case Qualifiers::OCL_Weak: 806 case Qualifiers::OCL_Strong: 807 case Qualifiers::OCL_Autoreleasing: 808 // FIXME: Can this happen? By this point, ValType should be known 809 // to be trivially copyable. 810 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 811 << ValType << Ptr->getSourceRange(); 812 return ExprError(); 813 } 814 815 QualType ResultType = ValType; 816 if (Form == Copy || Form == GNUXchg || Form == Init) 817 ResultType = Context.VoidTy; 818 else if (Form == C11CmpXchg || Form == GNUCmpXchg) 819 ResultType = Context.BoolTy; 820 821 // The type of a parameter passed 'by value'. In the GNU atomics, such 822 // arguments are actually passed as pointers. 823 QualType ByValType = ValType; // 'CP' 824 if (!IsC11 && !IsN) 825 ByValType = Ptr->getType(); 826 827 // The first argument --- the pointer --- has a fixed type; we 828 // deduce the types of the rest of the arguments accordingly. Walk 829 // the remaining arguments, converting them to the deduced value type. 830 for (unsigned i = 1; i != NumArgs[Form]; ++i) { 831 QualType Ty; 832 if (i < NumVals[Form] + 1) { 833 switch (i) { 834 case 1: 835 // The second argument is the non-atomic operand. For arithmetic, this 836 // is always passed by value, and for a compare_exchange it is always 837 // passed by address. For the rest, GNU uses by-address and C11 uses 838 // by-value. 839 assert(Form != Load); 840 if (Form == Init || (Form == Arithmetic && ValType->isIntegerType())) 841 Ty = ValType; 842 else if (Form == Copy || Form == Xchg) 843 Ty = ByValType; 844 else if (Form == Arithmetic) 845 Ty = Context.getPointerDiffType(); 846 else 847 Ty = Context.getPointerType(ValType.getUnqualifiedType()); 848 break; 849 case 2: 850 // The third argument to compare_exchange / GNU exchange is a 851 // (pointer to a) desired value. 852 Ty = ByValType; 853 break; 854 case 3: 855 // The fourth argument to GNU compare_exchange is a 'weak' flag. 856 Ty = Context.BoolTy; 857 break; 858 } 859 } else { 860 // The order(s) are always converted to int. 861 Ty = Context.IntTy; 862 } 863 864 InitializedEntity Entity = 865 InitializedEntity::InitializeParameter(Context, Ty, false); 866 ExprResult Arg = TheCall->getArg(i); 867 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 868 if (Arg.isInvalid()) 869 return true; 870 TheCall->setArg(i, Arg.get()); 871 } 872 873 // Permute the arguments into a 'consistent' order. 874 SmallVector<Expr*, 5> SubExprs; 875 SubExprs.push_back(Ptr); 876 switch (Form) { 877 case Init: 878 // Note, AtomicExpr::getVal1() has a special case for this atomic. 879 SubExprs.push_back(TheCall->getArg(1)); // Val1 880 break; 881 case Load: 882 SubExprs.push_back(TheCall->getArg(1)); // Order 883 break; 884 case Copy: 885 case Arithmetic: 886 case Xchg: 887 SubExprs.push_back(TheCall->getArg(2)); // Order 888 SubExprs.push_back(TheCall->getArg(1)); // Val1 889 break; 890 case GNUXchg: 891 // Note, AtomicExpr::getVal2() has a special case for this atomic. 892 SubExprs.push_back(TheCall->getArg(3)); // Order 893 SubExprs.push_back(TheCall->getArg(1)); // Val1 894 SubExprs.push_back(TheCall->getArg(2)); // Val2 895 break; 896 case C11CmpXchg: 897 SubExprs.push_back(TheCall->getArg(3)); // Order 898 SubExprs.push_back(TheCall->getArg(1)); // Val1 899 SubExprs.push_back(TheCall->getArg(4)); // OrderFail 900 SubExprs.push_back(TheCall->getArg(2)); // Val2 901 break; 902 case GNUCmpXchg: 903 SubExprs.push_back(TheCall->getArg(4)); // Order 904 SubExprs.push_back(TheCall->getArg(1)); // Val1 905 SubExprs.push_back(TheCall->getArg(5)); // OrderFail 906 SubExprs.push_back(TheCall->getArg(2)); // Val2 907 SubExprs.push_back(TheCall->getArg(3)); // Weak 908 break; 909 } 910 911 return Owned(new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(), 912 SubExprs, ResultType, Op, 913 TheCall->getRParenLoc())); 914} 915 916 917/// checkBuiltinArgument - Given a call to a builtin function, perform 918/// normal type-checking on the given argument, updating the call in 919/// place. This is useful when a builtin function requires custom 920/// type-checking for some of its arguments but not necessarily all of 921/// them. 922/// 923/// Returns true on error. 924static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) { 925 FunctionDecl *Fn = E->getDirectCallee(); 926 assert(Fn && "builtin call without direct callee!"); 927 928 ParmVarDecl *Param = Fn->getParamDecl(ArgIndex); 929 InitializedEntity Entity = 930 InitializedEntity::InitializeParameter(S.Context, Param); 931 932 ExprResult Arg = E->getArg(0); 933 Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg); 934 if (Arg.isInvalid()) 935 return true; 936 937 E->setArg(ArgIndex, Arg.take()); 938 return false; 939} 940 941/// SemaBuiltinAtomicOverloaded - We have a call to a function like 942/// __sync_fetch_and_add, which is an overloaded function based on the pointer 943/// type of its first argument. The main ActOnCallExpr routines have already 944/// promoted the types of arguments because all of these calls are prototyped as 945/// void(...). 946/// 947/// This function goes through and does final semantic checking for these 948/// builtins, 949ExprResult 950Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) { 951 CallExpr *TheCall = (CallExpr *)TheCallResult.get(); 952 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 953 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 954 955 // Ensure that we have at least one argument to do type inference from. 956 if (TheCall->getNumArgs() < 1) { 957 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 958 << 0 << 1 << TheCall->getNumArgs() 959 << TheCall->getCallee()->getSourceRange(); 960 return ExprError(); 961 } 962 963 // Inspect the first argument of the atomic builtin. This should always be 964 // a pointer type, whose element is an integral scalar or pointer type. 965 // Because it is a pointer type, we don't have to worry about any implicit 966 // casts here. 967 // FIXME: We don't allow floating point scalars as input. 968 Expr *FirstArg = TheCall->getArg(0); 969 ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg); 970 if (FirstArgResult.isInvalid()) 971 return ExprError(); 972 FirstArg = FirstArgResult.take(); 973 TheCall->setArg(0, FirstArg); 974 975 const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>(); 976 if (!pointerType) { 977 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 978 << FirstArg->getType() << FirstArg->getSourceRange(); 979 return ExprError(); 980 } 981 982 QualType ValType = pointerType->getPointeeType(); 983 if (!ValType->isIntegerType() && !ValType->isAnyPointerType() && 984 !ValType->isBlockPointerType()) { 985 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr) 986 << FirstArg->getType() << FirstArg->getSourceRange(); 987 return ExprError(); 988 } 989 990 switch (ValType.getObjCLifetime()) { 991 case Qualifiers::OCL_None: 992 case Qualifiers::OCL_ExplicitNone: 993 // okay 994 break; 995 996 case Qualifiers::OCL_Weak: 997 case Qualifiers::OCL_Strong: 998 case Qualifiers::OCL_Autoreleasing: 999 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 1000 << ValType << FirstArg->getSourceRange(); 1001 return ExprError(); 1002 } 1003 1004 // Strip any qualifiers off ValType. 1005 ValType = ValType.getUnqualifiedType(); 1006 1007 // The majority of builtins return a value, but a few have special return 1008 // types, so allow them to override appropriately below. 1009 QualType ResultType = ValType; 1010 1011 // We need to figure out which concrete builtin this maps onto. For example, 1012 // __sync_fetch_and_add with a 2 byte object turns into 1013 // __sync_fetch_and_add_2. 1014#define BUILTIN_ROW(x) \ 1015 { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \ 1016 Builtin::BI##x##_8, Builtin::BI##x##_16 } 1017 1018 static const unsigned BuiltinIndices[][5] = { 1019 BUILTIN_ROW(__sync_fetch_and_add), 1020 BUILTIN_ROW(__sync_fetch_and_sub), 1021 BUILTIN_ROW(__sync_fetch_and_or), 1022 BUILTIN_ROW(__sync_fetch_and_and), 1023 BUILTIN_ROW(__sync_fetch_and_xor), 1024 1025 BUILTIN_ROW(__sync_add_and_fetch), 1026 BUILTIN_ROW(__sync_sub_and_fetch), 1027 BUILTIN_ROW(__sync_and_and_fetch), 1028 BUILTIN_ROW(__sync_or_and_fetch), 1029 BUILTIN_ROW(__sync_xor_and_fetch), 1030 1031 BUILTIN_ROW(__sync_val_compare_and_swap), 1032 BUILTIN_ROW(__sync_bool_compare_and_swap), 1033 BUILTIN_ROW(__sync_lock_test_and_set), 1034 BUILTIN_ROW(__sync_lock_release), 1035 BUILTIN_ROW(__sync_swap) 1036 }; 1037#undef BUILTIN_ROW 1038 1039 // Determine the index of the size. 1040 unsigned SizeIndex; 1041 switch (Context.getTypeSizeInChars(ValType).getQuantity()) { 1042 case 1: SizeIndex = 0; break; 1043 case 2: SizeIndex = 1; break; 1044 case 4: SizeIndex = 2; break; 1045 case 8: SizeIndex = 3; break; 1046 case 16: SizeIndex = 4; break; 1047 default: 1048 Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size) 1049 << FirstArg->getType() << FirstArg->getSourceRange(); 1050 return ExprError(); 1051 } 1052 1053 // Each of these builtins has one pointer argument, followed by some number of 1054 // values (0, 1 or 2) followed by a potentially empty varags list of stuff 1055 // that we ignore. Find out which row of BuiltinIndices to read from as well 1056 // as the number of fixed args. 1057 unsigned BuiltinID = FDecl->getBuiltinID(); 1058 unsigned BuiltinIndex, NumFixed = 1; 1059 switch (BuiltinID) { 1060 default: llvm_unreachable("Unknown overloaded atomic builtin!"); 1061 case Builtin::BI__sync_fetch_and_add: 1062 case Builtin::BI__sync_fetch_and_add_1: 1063 case Builtin::BI__sync_fetch_and_add_2: 1064 case Builtin::BI__sync_fetch_and_add_4: 1065 case Builtin::BI__sync_fetch_and_add_8: 1066 case Builtin::BI__sync_fetch_and_add_16: 1067 BuiltinIndex = 0; 1068 break; 1069 1070 case Builtin::BI__sync_fetch_and_sub: 1071 case Builtin::BI__sync_fetch_and_sub_1: 1072 case Builtin::BI__sync_fetch_and_sub_2: 1073 case Builtin::BI__sync_fetch_and_sub_4: 1074 case Builtin::BI__sync_fetch_and_sub_8: 1075 case Builtin::BI__sync_fetch_and_sub_16: 1076 BuiltinIndex = 1; 1077 break; 1078 1079 case Builtin::BI__sync_fetch_and_or: 1080 case Builtin::BI__sync_fetch_and_or_1: 1081 case Builtin::BI__sync_fetch_and_or_2: 1082 case Builtin::BI__sync_fetch_and_or_4: 1083 case Builtin::BI__sync_fetch_and_or_8: 1084 case Builtin::BI__sync_fetch_and_or_16: 1085 BuiltinIndex = 2; 1086 break; 1087 1088 case Builtin::BI__sync_fetch_and_and: 1089 case Builtin::BI__sync_fetch_and_and_1: 1090 case Builtin::BI__sync_fetch_and_and_2: 1091 case Builtin::BI__sync_fetch_and_and_4: 1092 case Builtin::BI__sync_fetch_and_and_8: 1093 case Builtin::BI__sync_fetch_and_and_16: 1094 BuiltinIndex = 3; 1095 break; 1096 1097 case Builtin::BI__sync_fetch_and_xor: 1098 case Builtin::BI__sync_fetch_and_xor_1: 1099 case Builtin::BI__sync_fetch_and_xor_2: 1100 case Builtin::BI__sync_fetch_and_xor_4: 1101 case Builtin::BI__sync_fetch_and_xor_8: 1102 case Builtin::BI__sync_fetch_and_xor_16: 1103 BuiltinIndex = 4; 1104 break; 1105 1106 case Builtin::BI__sync_add_and_fetch: 1107 case Builtin::BI__sync_add_and_fetch_1: 1108 case Builtin::BI__sync_add_and_fetch_2: 1109 case Builtin::BI__sync_add_and_fetch_4: 1110 case Builtin::BI__sync_add_and_fetch_8: 1111 case Builtin::BI__sync_add_and_fetch_16: 1112 BuiltinIndex = 5; 1113 break; 1114 1115 case Builtin::BI__sync_sub_and_fetch: 1116 case Builtin::BI__sync_sub_and_fetch_1: 1117 case Builtin::BI__sync_sub_and_fetch_2: 1118 case Builtin::BI__sync_sub_and_fetch_4: 1119 case Builtin::BI__sync_sub_and_fetch_8: 1120 case Builtin::BI__sync_sub_and_fetch_16: 1121 BuiltinIndex = 6; 1122 break; 1123 1124 case Builtin::BI__sync_and_and_fetch: 1125 case Builtin::BI__sync_and_and_fetch_1: 1126 case Builtin::BI__sync_and_and_fetch_2: 1127 case Builtin::BI__sync_and_and_fetch_4: 1128 case Builtin::BI__sync_and_and_fetch_8: 1129 case Builtin::BI__sync_and_and_fetch_16: 1130 BuiltinIndex = 7; 1131 break; 1132 1133 case Builtin::BI__sync_or_and_fetch: 1134 case Builtin::BI__sync_or_and_fetch_1: 1135 case Builtin::BI__sync_or_and_fetch_2: 1136 case Builtin::BI__sync_or_and_fetch_4: 1137 case Builtin::BI__sync_or_and_fetch_8: 1138 case Builtin::BI__sync_or_and_fetch_16: 1139 BuiltinIndex = 8; 1140 break; 1141 1142 case Builtin::BI__sync_xor_and_fetch: 1143 case Builtin::BI__sync_xor_and_fetch_1: 1144 case Builtin::BI__sync_xor_and_fetch_2: 1145 case Builtin::BI__sync_xor_and_fetch_4: 1146 case Builtin::BI__sync_xor_and_fetch_8: 1147 case Builtin::BI__sync_xor_and_fetch_16: 1148 BuiltinIndex = 9; 1149 break; 1150 1151 case Builtin::BI__sync_val_compare_and_swap: 1152 case Builtin::BI__sync_val_compare_and_swap_1: 1153 case Builtin::BI__sync_val_compare_and_swap_2: 1154 case Builtin::BI__sync_val_compare_and_swap_4: 1155 case Builtin::BI__sync_val_compare_and_swap_8: 1156 case Builtin::BI__sync_val_compare_and_swap_16: 1157 BuiltinIndex = 10; 1158 NumFixed = 2; 1159 break; 1160 1161 case Builtin::BI__sync_bool_compare_and_swap: 1162 case Builtin::BI__sync_bool_compare_and_swap_1: 1163 case Builtin::BI__sync_bool_compare_and_swap_2: 1164 case Builtin::BI__sync_bool_compare_and_swap_4: 1165 case Builtin::BI__sync_bool_compare_and_swap_8: 1166 case Builtin::BI__sync_bool_compare_and_swap_16: 1167 BuiltinIndex = 11; 1168 NumFixed = 2; 1169 ResultType = Context.BoolTy; 1170 break; 1171 1172 case Builtin::BI__sync_lock_test_and_set: 1173 case Builtin::BI__sync_lock_test_and_set_1: 1174 case Builtin::BI__sync_lock_test_and_set_2: 1175 case Builtin::BI__sync_lock_test_and_set_4: 1176 case Builtin::BI__sync_lock_test_and_set_8: 1177 case Builtin::BI__sync_lock_test_and_set_16: 1178 BuiltinIndex = 12; 1179 break; 1180 1181 case Builtin::BI__sync_lock_release: 1182 case Builtin::BI__sync_lock_release_1: 1183 case Builtin::BI__sync_lock_release_2: 1184 case Builtin::BI__sync_lock_release_4: 1185 case Builtin::BI__sync_lock_release_8: 1186 case Builtin::BI__sync_lock_release_16: 1187 BuiltinIndex = 13; 1188 NumFixed = 0; 1189 ResultType = Context.VoidTy; 1190 break; 1191 1192 case Builtin::BI__sync_swap: 1193 case Builtin::BI__sync_swap_1: 1194 case Builtin::BI__sync_swap_2: 1195 case Builtin::BI__sync_swap_4: 1196 case Builtin::BI__sync_swap_8: 1197 case Builtin::BI__sync_swap_16: 1198 BuiltinIndex = 14; 1199 break; 1200 } 1201 1202 // Now that we know how many fixed arguments we expect, first check that we 1203 // have at least that many. 1204 if (TheCall->getNumArgs() < 1+NumFixed) { 1205 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 1206 << 0 << 1+NumFixed << TheCall->getNumArgs() 1207 << TheCall->getCallee()->getSourceRange(); 1208 return ExprError(); 1209 } 1210 1211 // Get the decl for the concrete builtin from this, we can tell what the 1212 // concrete integer type we should convert to is. 1213 unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex]; 1214 const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID); 1215 FunctionDecl *NewBuiltinDecl; 1216 if (NewBuiltinID == BuiltinID) 1217 NewBuiltinDecl = FDecl; 1218 else { 1219 // Perform builtin lookup to avoid redeclaring it. 1220 DeclarationName DN(&Context.Idents.get(NewBuiltinName)); 1221 LookupResult Res(*this, DN, DRE->getLocStart(), LookupOrdinaryName); 1222 LookupName(Res, TUScope, /*AllowBuiltinCreation=*/true); 1223 assert(Res.getFoundDecl()); 1224 NewBuiltinDecl = dyn_cast<FunctionDecl>(Res.getFoundDecl()); 1225 if (NewBuiltinDecl == 0) 1226 return ExprError(); 1227 } 1228 1229 // The first argument --- the pointer --- has a fixed type; we 1230 // deduce the types of the rest of the arguments accordingly. Walk 1231 // the remaining arguments, converting them to the deduced value type. 1232 for (unsigned i = 0; i != NumFixed; ++i) { 1233 ExprResult Arg = TheCall->getArg(i+1); 1234 1235 // GCC does an implicit conversion to the pointer or integer ValType. This 1236 // can fail in some cases (1i -> int**), check for this error case now. 1237 // Initialize the argument. 1238 InitializedEntity Entity = InitializedEntity::InitializeParameter(Context, 1239 ValType, /*consume*/ false); 1240 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 1241 if (Arg.isInvalid()) 1242 return ExprError(); 1243 1244 // Okay, we have something that *can* be converted to the right type. Check 1245 // to see if there is a potentially weird extension going on here. This can 1246 // happen when you do an atomic operation on something like an char* and 1247 // pass in 42. The 42 gets converted to char. This is even more strange 1248 // for things like 45.123 -> char, etc. 1249 // FIXME: Do this check. 1250 TheCall->setArg(i+1, Arg.take()); 1251 } 1252 1253 ASTContext& Context = this->getASTContext(); 1254 1255 // Create a new DeclRefExpr to refer to the new decl. 1256 DeclRefExpr* NewDRE = DeclRefExpr::Create( 1257 Context, 1258 DRE->getQualifierLoc(), 1259 SourceLocation(), 1260 NewBuiltinDecl, 1261 /*enclosing*/ false, 1262 DRE->getLocation(), 1263 Context.BuiltinFnTy, 1264 DRE->getValueKind()); 1265 1266 // Set the callee in the CallExpr. 1267 // FIXME: This loses syntactic information. 1268 QualType CalleePtrTy = Context.getPointerType(NewBuiltinDecl->getType()); 1269 ExprResult PromotedCall = ImpCastExprToType(NewDRE, CalleePtrTy, 1270 CK_BuiltinFnToFnPtr); 1271 TheCall->setCallee(PromotedCall.take()); 1272 1273 // Change the result type of the call to match the original value type. This 1274 // is arbitrary, but the codegen for these builtins ins design to handle it 1275 // gracefully. 1276 TheCall->setType(ResultType); 1277 1278 return TheCallResult; 1279} 1280 1281/// CheckObjCString - Checks that the argument to the builtin 1282/// CFString constructor is correct 1283/// Note: It might also make sense to do the UTF-16 conversion here (would 1284/// simplify the backend). 1285bool Sema::CheckObjCString(Expr *Arg) { 1286 Arg = Arg->IgnoreParenCasts(); 1287 StringLiteral *Literal = dyn_cast<StringLiteral>(Arg); 1288 1289 if (!Literal || !Literal->isAscii()) { 1290 Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant) 1291 << Arg->getSourceRange(); 1292 return true; 1293 } 1294 1295 if (Literal->containsNonAsciiOrNull()) { 1296 StringRef String = Literal->getString(); 1297 unsigned NumBytes = String.size(); 1298 SmallVector<UTF16, 128> ToBuf(NumBytes); 1299 const UTF8 *FromPtr = (const UTF8 *)String.data(); 1300 UTF16 *ToPtr = &ToBuf[0]; 1301 1302 ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, 1303 &ToPtr, ToPtr + NumBytes, 1304 strictConversion); 1305 // Check for conversion failure. 1306 if (Result != conversionOK) 1307 Diag(Arg->getLocStart(), 1308 diag::warn_cfstring_truncated) << Arg->getSourceRange(); 1309 } 1310 return false; 1311} 1312 1313/// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity. 1314/// Emit an error and return true on failure, return false on success. 1315bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) { 1316 Expr *Fn = TheCall->getCallee(); 1317 if (TheCall->getNumArgs() > 2) { 1318 Diag(TheCall->getArg(2)->getLocStart(), 1319 diag::err_typecheck_call_too_many_args) 1320 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1321 << Fn->getSourceRange() 1322 << SourceRange(TheCall->getArg(2)->getLocStart(), 1323 (*(TheCall->arg_end()-1))->getLocEnd()); 1324 return true; 1325 } 1326 1327 if (TheCall->getNumArgs() < 2) { 1328 return Diag(TheCall->getLocEnd(), 1329 diag::err_typecheck_call_too_few_args_at_least) 1330 << 0 /*function call*/ << 2 << TheCall->getNumArgs(); 1331 } 1332 1333 // Type-check the first argument normally. 1334 if (checkBuiltinArgument(*this, TheCall, 0)) 1335 return true; 1336 1337 // Determine whether the current function is variadic or not. 1338 BlockScopeInfo *CurBlock = getCurBlock(); 1339 bool isVariadic; 1340 if (CurBlock) 1341 isVariadic = CurBlock->TheDecl->isVariadic(); 1342 else if (FunctionDecl *FD = getCurFunctionDecl()) 1343 isVariadic = FD->isVariadic(); 1344 else 1345 isVariadic = getCurMethodDecl()->isVariadic(); 1346 1347 if (!isVariadic) { 1348 Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function); 1349 return true; 1350 } 1351 1352 // Verify that the second argument to the builtin is the last argument of the 1353 // current function or method. 1354 bool SecondArgIsLastNamedArgument = false; 1355 const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts(); 1356 1357 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) { 1358 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) { 1359 // FIXME: This isn't correct for methods (results in bogus warning). 1360 // Get the last formal in the current function. 1361 const ParmVarDecl *LastArg; 1362 if (CurBlock) 1363 LastArg = *(CurBlock->TheDecl->param_end()-1); 1364 else if (FunctionDecl *FD = getCurFunctionDecl()) 1365 LastArg = *(FD->param_end()-1); 1366 else 1367 LastArg = *(getCurMethodDecl()->param_end()-1); 1368 SecondArgIsLastNamedArgument = PV == LastArg; 1369 } 1370 } 1371 1372 if (!SecondArgIsLastNamedArgument) 1373 Diag(TheCall->getArg(1)->getLocStart(), 1374 diag::warn_second_parameter_of_va_start_not_last_named_argument); 1375 return false; 1376} 1377 1378/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and 1379/// friends. This is declared to take (...), so we have to check everything. 1380bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) { 1381 if (TheCall->getNumArgs() < 2) 1382 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 1383 << 0 << 2 << TheCall->getNumArgs()/*function call*/; 1384 if (TheCall->getNumArgs() > 2) 1385 return Diag(TheCall->getArg(2)->getLocStart(), 1386 diag::err_typecheck_call_too_many_args) 1387 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1388 << SourceRange(TheCall->getArg(2)->getLocStart(), 1389 (*(TheCall->arg_end()-1))->getLocEnd()); 1390 1391 ExprResult OrigArg0 = TheCall->getArg(0); 1392 ExprResult OrigArg1 = TheCall->getArg(1); 1393 1394 // Do standard promotions between the two arguments, returning their common 1395 // type. 1396 QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false); 1397 if (OrigArg0.isInvalid() || OrigArg1.isInvalid()) 1398 return true; 1399 1400 // Make sure any conversions are pushed back into the call; this is 1401 // type safe since unordered compare builtins are declared as "_Bool 1402 // foo(...)". 1403 TheCall->setArg(0, OrigArg0.get()); 1404 TheCall->setArg(1, OrigArg1.get()); 1405 1406 if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent()) 1407 return false; 1408 1409 // If the common type isn't a real floating type, then the arguments were 1410 // invalid for this operation. 1411 if (Res.isNull() || !Res->isRealFloatingType()) 1412 return Diag(OrigArg0.get()->getLocStart(), 1413 diag::err_typecheck_call_invalid_ordered_compare) 1414 << OrigArg0.get()->getType() << OrigArg1.get()->getType() 1415 << SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd()); 1416 1417 return false; 1418} 1419 1420/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like 1421/// __builtin_isnan and friends. This is declared to take (...), so we have 1422/// to check everything. We expect the last argument to be a floating point 1423/// value. 1424bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) { 1425 if (TheCall->getNumArgs() < NumArgs) 1426 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 1427 << 0 << NumArgs << TheCall->getNumArgs()/*function call*/; 1428 if (TheCall->getNumArgs() > NumArgs) 1429 return Diag(TheCall->getArg(NumArgs)->getLocStart(), 1430 diag::err_typecheck_call_too_many_args) 1431 << 0 /*function call*/ << NumArgs << TheCall->getNumArgs() 1432 << SourceRange(TheCall->getArg(NumArgs)->getLocStart(), 1433 (*(TheCall->arg_end()-1))->getLocEnd()); 1434 1435 Expr *OrigArg = TheCall->getArg(NumArgs-1); 1436 1437 if (OrigArg->isTypeDependent()) 1438 return false; 1439 1440 // This operation requires a non-_Complex floating-point number. 1441 if (!OrigArg->getType()->isRealFloatingType()) 1442 return Diag(OrigArg->getLocStart(), 1443 diag::err_typecheck_call_invalid_unary_fp) 1444 << OrigArg->getType() << OrigArg->getSourceRange(); 1445 1446 // If this is an implicit conversion from float -> double, remove it. 1447 if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) { 1448 Expr *CastArg = Cast->getSubExpr(); 1449 if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) { 1450 assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) && 1451 "promotion from float to double is the only expected cast here"); 1452 Cast->setSubExpr(0); 1453 TheCall->setArg(NumArgs-1, CastArg); 1454 } 1455 } 1456 1457 return false; 1458} 1459 1460/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector. 1461// This is declared to take (...), so we have to check everything. 1462ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) { 1463 if (TheCall->getNumArgs() < 2) 1464 return ExprError(Diag(TheCall->getLocEnd(), 1465 diag::err_typecheck_call_too_few_args_at_least) 1466 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1467 << TheCall->getSourceRange()); 1468 1469 // Determine which of the following types of shufflevector we're checking: 1470 // 1) unary, vector mask: (lhs, mask) 1471 // 2) binary, vector mask: (lhs, rhs, mask) 1472 // 3) binary, scalar mask: (lhs, rhs, index, ..., index) 1473 QualType resType = TheCall->getArg(0)->getType(); 1474 unsigned numElements = 0; 1475 1476 if (!TheCall->getArg(0)->isTypeDependent() && 1477 !TheCall->getArg(1)->isTypeDependent()) { 1478 QualType LHSType = TheCall->getArg(0)->getType(); 1479 QualType RHSType = TheCall->getArg(1)->getType(); 1480 1481 if (!LHSType->isVectorType() || !RHSType->isVectorType()) { 1482 Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector) 1483 << SourceRange(TheCall->getArg(0)->getLocStart(), 1484 TheCall->getArg(1)->getLocEnd()); 1485 return ExprError(); 1486 } 1487 1488 numElements = LHSType->getAs<VectorType>()->getNumElements(); 1489 unsigned numResElements = TheCall->getNumArgs() - 2; 1490 1491 // Check to see if we have a call with 2 vector arguments, the unary shuffle 1492 // with mask. If so, verify that RHS is an integer vector type with the 1493 // same number of elts as lhs. 1494 if (TheCall->getNumArgs() == 2) { 1495 if (!RHSType->hasIntegerRepresentation() || 1496 RHSType->getAs<VectorType>()->getNumElements() != numElements) 1497 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 1498 << SourceRange(TheCall->getArg(1)->getLocStart(), 1499 TheCall->getArg(1)->getLocEnd()); 1500 numResElements = numElements; 1501 } 1502 else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) { 1503 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 1504 << SourceRange(TheCall->getArg(0)->getLocStart(), 1505 TheCall->getArg(1)->getLocEnd()); 1506 return ExprError(); 1507 } else if (numElements != numResElements) { 1508 QualType eltType = LHSType->getAs<VectorType>()->getElementType(); 1509 resType = Context.getVectorType(eltType, numResElements, 1510 VectorType::GenericVector); 1511 } 1512 } 1513 1514 for (unsigned i = 2; i < TheCall->getNumArgs(); i++) { 1515 if (TheCall->getArg(i)->isTypeDependent() || 1516 TheCall->getArg(i)->isValueDependent()) 1517 continue; 1518 1519 llvm::APSInt Result(32); 1520 if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context)) 1521 return ExprError(Diag(TheCall->getLocStart(), 1522 diag::err_shufflevector_nonconstant_argument) 1523 << TheCall->getArg(i)->getSourceRange()); 1524 1525 if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2) 1526 return ExprError(Diag(TheCall->getLocStart(), 1527 diag::err_shufflevector_argument_too_large) 1528 << TheCall->getArg(i)->getSourceRange()); 1529 } 1530 1531 SmallVector<Expr*, 32> exprs; 1532 1533 for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) { 1534 exprs.push_back(TheCall->getArg(i)); 1535 TheCall->setArg(i, 0); 1536 } 1537 1538 return Owned(new (Context) ShuffleVectorExpr(Context, exprs, resType, 1539 TheCall->getCallee()->getLocStart(), 1540 TheCall->getRParenLoc())); 1541} 1542 1543/// SemaBuiltinPrefetch - Handle __builtin_prefetch. 1544// This is declared to take (const void*, ...) and can take two 1545// optional constant int args. 1546bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) { 1547 unsigned NumArgs = TheCall->getNumArgs(); 1548 1549 if (NumArgs > 3) 1550 return Diag(TheCall->getLocEnd(), 1551 diag::err_typecheck_call_too_many_args_at_most) 1552 << 0 /*function call*/ << 3 << NumArgs 1553 << TheCall->getSourceRange(); 1554 1555 // Argument 0 is checked for us and the remaining arguments must be 1556 // constant integers. 1557 for (unsigned i = 1; i != NumArgs; ++i) { 1558 Expr *Arg = TheCall->getArg(i); 1559 1560 // We can't check the value of a dependent argument. 1561 if (Arg->isTypeDependent() || Arg->isValueDependent()) 1562 continue; 1563 1564 llvm::APSInt Result; 1565 if (SemaBuiltinConstantArg(TheCall, i, Result)) 1566 return true; 1567 1568 // FIXME: gcc issues a warning and rewrites these to 0. These 1569 // seems especially odd for the third argument since the default 1570 // is 3. 1571 if (i == 1) { 1572 if (Result.getLimitedValue() > 1) 1573 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1574 << "0" << "1" << Arg->getSourceRange(); 1575 } else { 1576 if (Result.getLimitedValue() > 3) 1577 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1578 << "0" << "3" << Arg->getSourceRange(); 1579 } 1580 } 1581 1582 return false; 1583} 1584 1585/// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr 1586/// TheCall is a constant expression. 1587bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum, 1588 llvm::APSInt &Result) { 1589 Expr *Arg = TheCall->getArg(ArgNum); 1590 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 1591 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 1592 1593 if (Arg->isTypeDependent() || Arg->isValueDependent()) return false; 1594 1595 if (!Arg->isIntegerConstantExpr(Result, Context)) 1596 return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type) 1597 << FDecl->getDeclName() << Arg->getSourceRange(); 1598 1599 return false; 1600} 1601 1602/// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr, 1603/// int type). This simply type checks that type is one of the defined 1604/// constants (0-3). 1605// For compatibility check 0-3, llvm only handles 0 and 2. 1606bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) { 1607 llvm::APSInt Result; 1608 1609 // We can't check the value of a dependent argument. 1610 if (TheCall->getArg(1)->isTypeDependent() || 1611 TheCall->getArg(1)->isValueDependent()) 1612 return false; 1613 1614 // Check constant-ness first. 1615 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 1616 return true; 1617 1618 Expr *Arg = TheCall->getArg(1); 1619 if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) { 1620 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1621 << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 1622 } 1623 1624 return false; 1625} 1626 1627/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val). 1628/// This checks that val is a constant 1. 1629bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) { 1630 Expr *Arg = TheCall->getArg(1); 1631 llvm::APSInt Result; 1632 1633 // TODO: This is less than ideal. Overload this to take a value. 1634 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 1635 return true; 1636 1637 if (Result != 1) 1638 return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val) 1639 << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 1640 1641 return false; 1642} 1643 1644// Determine if an expression is a string literal or constant string. 1645// If this function returns false on the arguments to a function expecting a 1646// format string, we will usually need to emit a warning. 1647// True string literals are then checked by CheckFormatString. 1648Sema::StringLiteralCheckType 1649Sema::checkFormatStringExpr(const Expr *E, Expr **Args, 1650 unsigned NumArgs, bool HasVAListArg, 1651 unsigned format_idx, unsigned firstDataArg, 1652 FormatStringType Type, VariadicCallType CallType, 1653 bool inFunctionCall) { 1654 tryAgain: 1655 if (E->isTypeDependent() || E->isValueDependent()) 1656 return SLCT_NotALiteral; 1657 1658 E = E->IgnoreParenCasts(); 1659 1660 if (E->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull)) 1661 // Technically -Wformat-nonliteral does not warn about this case. 1662 // The behavior of printf and friends in this case is implementation 1663 // dependent. Ideally if the format string cannot be null then 1664 // it should have a 'nonnull' attribute in the function prototype. 1665 return SLCT_CheckedLiteral; 1666 1667 switch (E->getStmtClass()) { 1668 case Stmt::BinaryConditionalOperatorClass: 1669 case Stmt::ConditionalOperatorClass: { 1670 // The expression is a literal if both sub-expressions were, and it was 1671 // completely checked only if both sub-expressions were checked. 1672 const AbstractConditionalOperator *C = 1673 cast<AbstractConditionalOperator>(E); 1674 StringLiteralCheckType Left = 1675 checkFormatStringExpr(C->getTrueExpr(), Args, NumArgs, 1676 HasVAListArg, format_idx, firstDataArg, 1677 Type, CallType, inFunctionCall); 1678 if (Left == SLCT_NotALiteral) 1679 return SLCT_NotALiteral; 1680 StringLiteralCheckType Right = 1681 checkFormatStringExpr(C->getFalseExpr(), Args, NumArgs, 1682 HasVAListArg, format_idx, firstDataArg, 1683 Type, CallType, inFunctionCall); 1684 return Left < Right ? Left : Right; 1685 } 1686 1687 case Stmt::ImplicitCastExprClass: { 1688 E = cast<ImplicitCastExpr>(E)->getSubExpr(); 1689 goto tryAgain; 1690 } 1691 1692 case Stmt::OpaqueValueExprClass: 1693 if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) { 1694 E = src; 1695 goto tryAgain; 1696 } 1697 return SLCT_NotALiteral; 1698 1699 case Stmt::PredefinedExprClass: 1700 // While __func__, etc., are technically not string literals, they 1701 // cannot contain format specifiers and thus are not a security 1702 // liability. 1703 return SLCT_UncheckedLiteral; 1704 1705 case Stmt::DeclRefExprClass: { 1706 const DeclRefExpr *DR = cast<DeclRefExpr>(E); 1707 1708 // As an exception, do not flag errors for variables binding to 1709 // const string literals. 1710 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) { 1711 bool isConstant = false; 1712 QualType T = DR->getType(); 1713 1714 if (const ArrayType *AT = Context.getAsArrayType(T)) { 1715 isConstant = AT->getElementType().isConstant(Context); 1716 } else if (const PointerType *PT = T->getAs<PointerType>()) { 1717 isConstant = T.isConstant(Context) && 1718 PT->getPointeeType().isConstant(Context); 1719 } else if (T->isObjCObjectPointerType()) { 1720 // In ObjC, there is usually no "const ObjectPointer" type, 1721 // so don't check if the pointee type is constant. 1722 isConstant = T.isConstant(Context); 1723 } 1724 1725 if (isConstant) { 1726 if (const Expr *Init = VD->getAnyInitializer()) { 1727 // Look through initializers like const char c[] = { "foo" } 1728 if (const InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) { 1729 if (InitList->isStringLiteralInit()) 1730 Init = InitList->getInit(0)->IgnoreParenImpCasts(); 1731 } 1732 return checkFormatStringExpr(Init, Args, NumArgs, 1733 HasVAListArg, format_idx, 1734 firstDataArg, Type, CallType, 1735 /*inFunctionCall*/false); 1736 } 1737 } 1738 1739 // For vprintf* functions (i.e., HasVAListArg==true), we add a 1740 // special check to see if the format string is a function parameter 1741 // of the function calling the printf function. If the function 1742 // has an attribute indicating it is a printf-like function, then we 1743 // should suppress warnings concerning non-literals being used in a call 1744 // to a vprintf function. For example: 1745 // 1746 // void 1747 // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){ 1748 // va_list ap; 1749 // va_start(ap, fmt); 1750 // vprintf(fmt, ap); // Do NOT emit a warning about "fmt". 1751 // ... 1752 // 1753 if (HasVAListArg) { 1754 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(VD)) { 1755 if (const NamedDecl *ND = dyn_cast<NamedDecl>(PV->getDeclContext())) { 1756 int PVIndex = PV->getFunctionScopeIndex() + 1; 1757 for (specific_attr_iterator<FormatAttr> 1758 i = ND->specific_attr_begin<FormatAttr>(), 1759 e = ND->specific_attr_end<FormatAttr>(); i != e ; ++i) { 1760 FormatAttr *PVFormat = *i; 1761 // adjust for implicit parameter 1762 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 1763 if (MD->isInstance()) 1764 ++PVIndex; 1765 // We also check if the formats are compatible. 1766 // We can't pass a 'scanf' string to a 'printf' function. 1767 if (PVIndex == PVFormat->getFormatIdx() && 1768 Type == GetFormatStringType(PVFormat)) 1769 return SLCT_UncheckedLiteral; 1770 } 1771 } 1772 } 1773 } 1774 } 1775 1776 return SLCT_NotALiteral; 1777 } 1778 1779 case Stmt::CallExprClass: 1780 case Stmt::CXXMemberCallExprClass: { 1781 const CallExpr *CE = cast<CallExpr>(E); 1782 if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) { 1783 if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) { 1784 unsigned ArgIndex = FA->getFormatIdx(); 1785 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 1786 if (MD->isInstance()) 1787 --ArgIndex; 1788 const Expr *Arg = CE->getArg(ArgIndex - 1); 1789 1790 return checkFormatStringExpr(Arg, Args, NumArgs, 1791 HasVAListArg, format_idx, firstDataArg, 1792 Type, CallType, inFunctionCall); 1793 } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) { 1794 unsigned BuiltinID = FD->getBuiltinID(); 1795 if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString || 1796 BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) { 1797 const Expr *Arg = CE->getArg(0); 1798 return checkFormatStringExpr(Arg, Args, NumArgs, 1799 HasVAListArg, format_idx, 1800 firstDataArg, Type, CallType, 1801 inFunctionCall); 1802 } 1803 } 1804 } 1805 1806 return SLCT_NotALiteral; 1807 } 1808 case Stmt::ObjCStringLiteralClass: 1809 case Stmt::StringLiteralClass: { 1810 const StringLiteral *StrE = NULL; 1811 1812 if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E)) 1813 StrE = ObjCFExpr->getString(); 1814 else 1815 StrE = cast<StringLiteral>(E); 1816 1817 if (StrE) { 1818 CheckFormatString(StrE, E, Args, NumArgs, HasVAListArg, format_idx, 1819 firstDataArg, Type, inFunctionCall, CallType); 1820 return SLCT_CheckedLiteral; 1821 } 1822 1823 return SLCT_NotALiteral; 1824 } 1825 1826 default: 1827 return SLCT_NotALiteral; 1828 } 1829} 1830 1831void 1832Sema::CheckNonNullArguments(const NonNullAttr *NonNull, 1833 const Expr * const *ExprArgs, 1834 SourceLocation CallSiteLoc) { 1835 for (NonNullAttr::args_iterator i = NonNull->args_begin(), 1836 e = NonNull->args_end(); 1837 i != e; ++i) { 1838 const Expr *ArgExpr = ExprArgs[*i]; 1839 if (ArgExpr->isNullPointerConstant(Context, 1840 Expr::NPC_ValueDependentIsNotNull)) 1841 Diag(CallSiteLoc, diag::warn_null_arg) << ArgExpr->getSourceRange(); 1842 } 1843} 1844 1845Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) { 1846 return llvm::StringSwitch<FormatStringType>(Format->getType()) 1847 .Case("scanf", FST_Scanf) 1848 .Cases("printf", "printf0", FST_Printf) 1849 .Cases("NSString", "CFString", FST_NSString) 1850 .Case("strftime", FST_Strftime) 1851 .Case("strfmon", FST_Strfmon) 1852 .Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf) 1853 .Default(FST_Unknown); 1854} 1855 1856/// CheckFormatArguments - Check calls to printf and scanf (and similar 1857/// functions) for correct use of format strings. 1858/// Returns true if a format string has been fully checked. 1859bool Sema::CheckFormatArguments(const FormatAttr *Format, Expr **Args, 1860 unsigned NumArgs, bool IsCXXMember, 1861 VariadicCallType CallType, 1862 SourceLocation Loc, SourceRange Range) { 1863 FormatStringInfo FSI; 1864 if (getFormatStringInfo(Format, IsCXXMember, &FSI)) 1865 return CheckFormatArguments(Args, NumArgs, FSI.HasVAListArg, FSI.FormatIdx, 1866 FSI.FirstDataArg, GetFormatStringType(Format), 1867 CallType, Loc, Range); 1868 return false; 1869} 1870 1871bool Sema::CheckFormatArguments(Expr **Args, unsigned NumArgs, 1872 bool HasVAListArg, unsigned format_idx, 1873 unsigned firstDataArg, FormatStringType Type, 1874 VariadicCallType CallType, 1875 SourceLocation Loc, SourceRange Range) { 1876 // CHECK: printf/scanf-like function is called with no format string. 1877 if (format_idx >= NumArgs) { 1878 Diag(Loc, diag::warn_missing_format_string) << Range; 1879 return false; 1880 } 1881 1882 const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts(); 1883 1884 // CHECK: format string is not a string literal. 1885 // 1886 // Dynamically generated format strings are difficult to 1887 // automatically vet at compile time. Requiring that format strings 1888 // are string literals: (1) permits the checking of format strings by 1889 // the compiler and thereby (2) can practically remove the source of 1890 // many format string exploits. 1891 1892 // Format string can be either ObjC string (e.g. @"%d") or 1893 // C string (e.g. "%d") 1894 // ObjC string uses the same format specifiers as C string, so we can use 1895 // the same format string checking logic for both ObjC and C strings. 1896 StringLiteralCheckType CT = 1897 checkFormatStringExpr(OrigFormatExpr, Args, NumArgs, HasVAListArg, 1898 format_idx, firstDataArg, Type, CallType); 1899 if (CT != SLCT_NotALiteral) 1900 // Literal format string found, check done! 1901 return CT == SLCT_CheckedLiteral; 1902 1903 // Strftime is particular as it always uses a single 'time' argument, 1904 // so it is safe to pass a non-literal string. 1905 if (Type == FST_Strftime) 1906 return false; 1907 1908 // Do not emit diag when the string param is a macro expansion and the 1909 // format is either NSString or CFString. This is a hack to prevent 1910 // diag when using the NSLocalizedString and CFCopyLocalizedString macros 1911 // which are usually used in place of NS and CF string literals. 1912 if (Type == FST_NSString && 1913 SourceMgr.isInSystemMacro(Args[format_idx]->getLocStart())) 1914 return false; 1915 1916 // If there are no arguments specified, warn with -Wformat-security, otherwise 1917 // warn only with -Wformat-nonliteral. 1918 if (NumArgs == format_idx+1) 1919 Diag(Args[format_idx]->getLocStart(), 1920 diag::warn_format_nonliteral_noargs) 1921 << OrigFormatExpr->getSourceRange(); 1922 else 1923 Diag(Args[format_idx]->getLocStart(), 1924 diag::warn_format_nonliteral) 1925 << OrigFormatExpr->getSourceRange(); 1926 return false; 1927} 1928 1929namespace { 1930class CheckFormatHandler : public analyze_format_string::FormatStringHandler { 1931protected: 1932 Sema &S; 1933 const StringLiteral *FExpr; 1934 const Expr *OrigFormatExpr; 1935 const unsigned FirstDataArg; 1936 const unsigned NumDataArgs; 1937 const char *Beg; // Start of format string. 1938 const bool HasVAListArg; 1939 const Expr * const *Args; 1940 const unsigned NumArgs; 1941 unsigned FormatIdx; 1942 llvm::BitVector CoveredArgs; 1943 bool usesPositionalArgs; 1944 bool atFirstArg; 1945 bool inFunctionCall; 1946 Sema::VariadicCallType CallType; 1947public: 1948 CheckFormatHandler(Sema &s, const StringLiteral *fexpr, 1949 const Expr *origFormatExpr, unsigned firstDataArg, 1950 unsigned numDataArgs, const char *beg, bool hasVAListArg, 1951 Expr **args, unsigned numArgs, 1952 unsigned formatIdx, bool inFunctionCall, 1953 Sema::VariadicCallType callType) 1954 : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr), 1955 FirstDataArg(firstDataArg), NumDataArgs(numDataArgs), 1956 Beg(beg), HasVAListArg(hasVAListArg), 1957 Args(args), NumArgs(numArgs), FormatIdx(formatIdx), 1958 usesPositionalArgs(false), atFirstArg(true), 1959 inFunctionCall(inFunctionCall), CallType(callType) { 1960 CoveredArgs.resize(numDataArgs); 1961 CoveredArgs.reset(); 1962 } 1963 1964 void DoneProcessing(); 1965 1966 void HandleIncompleteSpecifier(const char *startSpecifier, 1967 unsigned specifierLen); 1968 1969 void HandleInvalidLengthModifier( 1970 const analyze_format_string::FormatSpecifier &FS, 1971 const analyze_format_string::ConversionSpecifier &CS, 1972 const char *startSpecifier, unsigned specifierLen, unsigned DiagID); 1973 1974 void HandleNonStandardLengthModifier( 1975 const analyze_format_string::FormatSpecifier &FS, 1976 const char *startSpecifier, unsigned specifierLen); 1977 1978 void HandleNonStandardConversionSpecifier( 1979 const analyze_format_string::ConversionSpecifier &CS, 1980 const char *startSpecifier, unsigned specifierLen); 1981 1982 virtual void HandlePosition(const char *startPos, unsigned posLen); 1983 1984 virtual void HandleInvalidPosition(const char *startSpecifier, 1985 unsigned specifierLen, 1986 analyze_format_string::PositionContext p); 1987 1988 virtual void HandleZeroPosition(const char *startPos, unsigned posLen); 1989 1990 void HandleNullChar(const char *nullCharacter); 1991 1992 template <typename Range> 1993 static void EmitFormatDiagnostic(Sema &S, bool inFunctionCall, 1994 const Expr *ArgumentExpr, 1995 PartialDiagnostic PDiag, 1996 SourceLocation StringLoc, 1997 bool IsStringLocation, Range StringRange, 1998 ArrayRef<FixItHint> Fixit = ArrayRef<FixItHint>()); 1999 2000protected: 2001 bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc, 2002 const char *startSpec, 2003 unsigned specifierLen, 2004 const char *csStart, unsigned csLen); 2005 2006 void HandlePositionalNonpositionalArgs(SourceLocation Loc, 2007 const char *startSpec, 2008 unsigned specifierLen); 2009 2010 SourceRange getFormatStringRange(); 2011 CharSourceRange getSpecifierRange(const char *startSpecifier, 2012 unsigned specifierLen); 2013 SourceLocation getLocationOfByte(const char *x); 2014 2015 const Expr *getDataArg(unsigned i) const; 2016 2017 bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS, 2018 const analyze_format_string::ConversionSpecifier &CS, 2019 const char *startSpecifier, unsigned specifierLen, 2020 unsigned argIndex); 2021 2022 template <typename Range> 2023 void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc, 2024 bool IsStringLocation, Range StringRange, 2025 ArrayRef<FixItHint> Fixit = ArrayRef<FixItHint>()); 2026 2027 void CheckPositionalAndNonpositionalArgs( 2028 const analyze_format_string::FormatSpecifier *FS); 2029}; 2030} 2031 2032SourceRange CheckFormatHandler::getFormatStringRange() { 2033 return OrigFormatExpr->getSourceRange(); 2034} 2035 2036CharSourceRange CheckFormatHandler:: 2037getSpecifierRange(const char *startSpecifier, unsigned specifierLen) { 2038 SourceLocation Start = getLocationOfByte(startSpecifier); 2039 SourceLocation End = getLocationOfByte(startSpecifier + specifierLen - 1); 2040 2041 // Advance the end SourceLocation by one due to half-open ranges. 2042 End = End.getLocWithOffset(1); 2043 2044 return CharSourceRange::getCharRange(Start, End); 2045} 2046 2047SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) { 2048 return S.getLocationOfStringLiteralByte(FExpr, x - Beg); 2049} 2050 2051void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier, 2052 unsigned specifierLen){ 2053 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier), 2054 getLocationOfByte(startSpecifier), 2055 /*IsStringLocation*/true, 2056 getSpecifierRange(startSpecifier, specifierLen)); 2057} 2058 2059void CheckFormatHandler::HandleInvalidLengthModifier( 2060 const analyze_format_string::FormatSpecifier &FS, 2061 const analyze_format_string::ConversionSpecifier &CS, 2062 const char *startSpecifier, unsigned specifierLen, unsigned DiagID) { 2063 using namespace analyze_format_string; 2064 2065 const LengthModifier &LM = FS.getLengthModifier(); 2066 CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength()); 2067 2068 // See if we know how to fix this length modifier. 2069 llvm::Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier(); 2070 if (FixedLM) { 2071 EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(), 2072 getLocationOfByte(LM.getStart()), 2073 /*IsStringLocation*/true, 2074 getSpecifierRange(startSpecifier, specifierLen)); 2075 2076 S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier) 2077 << FixedLM->toString() 2078 << FixItHint::CreateReplacement(LMRange, FixedLM->toString()); 2079 2080 } else { 2081 FixItHint Hint; 2082 if (DiagID == diag::warn_format_nonsensical_length) 2083 Hint = FixItHint::CreateRemoval(LMRange); 2084 2085 EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(), 2086 getLocationOfByte(LM.getStart()), 2087 /*IsStringLocation*/true, 2088 getSpecifierRange(startSpecifier, specifierLen), 2089 Hint); 2090 } 2091} 2092 2093void CheckFormatHandler::HandleNonStandardLengthModifier( 2094 const analyze_format_string::FormatSpecifier &FS, 2095 const char *startSpecifier, unsigned specifierLen) { 2096 using namespace analyze_format_string; 2097 2098 const LengthModifier &LM = FS.getLengthModifier(); 2099 CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength()); 2100 2101 // See if we know how to fix this length modifier. 2102 llvm::Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier(); 2103 if (FixedLM) { 2104 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2105 << LM.toString() << 0, 2106 getLocationOfByte(LM.getStart()), 2107 /*IsStringLocation*/true, 2108 getSpecifierRange(startSpecifier, specifierLen)); 2109 2110 S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier) 2111 << FixedLM->toString() 2112 << FixItHint::CreateReplacement(LMRange, FixedLM->toString()); 2113 2114 } else { 2115 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2116 << LM.toString() << 0, 2117 getLocationOfByte(LM.getStart()), 2118 /*IsStringLocation*/true, 2119 getSpecifierRange(startSpecifier, specifierLen)); 2120 } 2121} 2122 2123void CheckFormatHandler::HandleNonStandardConversionSpecifier( 2124 const analyze_format_string::ConversionSpecifier &CS, 2125 const char *startSpecifier, unsigned specifierLen) { 2126 using namespace analyze_format_string; 2127 2128 // See if we know how to fix this conversion specifier. 2129 llvm::Optional<ConversionSpecifier> FixedCS = CS.getStandardSpecifier(); 2130 if (FixedCS) { 2131 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2132 << CS.toString() << /*conversion specifier*/1, 2133 getLocationOfByte(CS.getStart()), 2134 /*IsStringLocation*/true, 2135 getSpecifierRange(startSpecifier, specifierLen)); 2136 2137 CharSourceRange CSRange = getSpecifierRange(CS.getStart(), CS.getLength()); 2138 S.Diag(getLocationOfByte(CS.getStart()), diag::note_format_fix_specifier) 2139 << FixedCS->toString() 2140 << FixItHint::CreateReplacement(CSRange, FixedCS->toString()); 2141 } else { 2142 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2143 << CS.toString() << /*conversion specifier*/1, 2144 getLocationOfByte(CS.getStart()), 2145 /*IsStringLocation*/true, 2146 getSpecifierRange(startSpecifier, specifierLen)); 2147 } 2148} 2149 2150void CheckFormatHandler::HandlePosition(const char *startPos, 2151 unsigned posLen) { 2152 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg), 2153 getLocationOfByte(startPos), 2154 /*IsStringLocation*/true, 2155 getSpecifierRange(startPos, posLen)); 2156} 2157 2158void 2159CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen, 2160 analyze_format_string::PositionContext p) { 2161 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier) 2162 << (unsigned) p, 2163 getLocationOfByte(startPos), /*IsStringLocation*/true, 2164 getSpecifierRange(startPos, posLen)); 2165} 2166 2167void CheckFormatHandler::HandleZeroPosition(const char *startPos, 2168 unsigned posLen) { 2169 EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier), 2170 getLocationOfByte(startPos), 2171 /*IsStringLocation*/true, 2172 getSpecifierRange(startPos, posLen)); 2173} 2174 2175void CheckFormatHandler::HandleNullChar(const char *nullCharacter) { 2176 if (!isa<ObjCStringLiteral>(OrigFormatExpr)) { 2177 // The presence of a null character is likely an error. 2178 EmitFormatDiagnostic( 2179 S.PDiag(diag::warn_printf_format_string_contains_null_char), 2180 getLocationOfByte(nullCharacter), /*IsStringLocation*/true, 2181 getFormatStringRange()); 2182 } 2183} 2184 2185// Note that this may return NULL if there was an error parsing or building 2186// one of the argument expressions. 2187const Expr *CheckFormatHandler::getDataArg(unsigned i) const { 2188 return Args[FirstDataArg + i]; 2189} 2190 2191void CheckFormatHandler::DoneProcessing() { 2192 // Does the number of data arguments exceed the number of 2193 // format conversions in the format string? 2194 if (!HasVAListArg) { 2195 // Find any arguments that weren't covered. 2196 CoveredArgs.flip(); 2197 signed notCoveredArg = CoveredArgs.find_first(); 2198 if (notCoveredArg >= 0) { 2199 assert((unsigned)notCoveredArg < NumDataArgs); 2200 if (const Expr *E = getDataArg((unsigned) notCoveredArg)) { 2201 SourceLocation Loc = E->getLocStart(); 2202 if (!S.getSourceManager().isInSystemMacro(Loc)) { 2203 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_data_arg_not_used), 2204 Loc, /*IsStringLocation*/false, 2205 getFormatStringRange()); 2206 } 2207 } 2208 } 2209 } 2210} 2211 2212bool 2213CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex, 2214 SourceLocation Loc, 2215 const char *startSpec, 2216 unsigned specifierLen, 2217 const char *csStart, 2218 unsigned csLen) { 2219 2220 bool keepGoing = true; 2221 if (argIndex < NumDataArgs) { 2222 // Consider the argument coverered, even though the specifier doesn't 2223 // make sense. 2224 CoveredArgs.set(argIndex); 2225 } 2226 else { 2227 // If argIndex exceeds the number of data arguments we 2228 // don't issue a warning because that is just a cascade of warnings (and 2229 // they may have intended '%%' anyway). We don't want to continue processing 2230 // the format string after this point, however, as we will like just get 2231 // gibberish when trying to match arguments. 2232 keepGoing = false; 2233 } 2234 2235 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion) 2236 << StringRef(csStart, csLen), 2237 Loc, /*IsStringLocation*/true, 2238 getSpecifierRange(startSpec, specifierLen)); 2239 2240 return keepGoing; 2241} 2242 2243void 2244CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc, 2245 const char *startSpec, 2246 unsigned specifierLen) { 2247 EmitFormatDiagnostic( 2248 S.PDiag(diag::warn_format_mix_positional_nonpositional_args), 2249 Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen)); 2250} 2251 2252bool 2253CheckFormatHandler::CheckNumArgs( 2254 const analyze_format_string::FormatSpecifier &FS, 2255 const analyze_format_string::ConversionSpecifier &CS, 2256 const char *startSpecifier, unsigned specifierLen, unsigned argIndex) { 2257 2258 if (argIndex >= NumDataArgs) { 2259 PartialDiagnostic PDiag = FS.usesPositionalArg() 2260 ? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args) 2261 << (argIndex+1) << NumDataArgs) 2262 : S.PDiag(diag::warn_printf_insufficient_data_args); 2263 EmitFormatDiagnostic( 2264 PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true, 2265 getSpecifierRange(startSpecifier, specifierLen)); 2266 return false; 2267 } 2268 return true; 2269} 2270 2271template<typename Range> 2272void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag, 2273 SourceLocation Loc, 2274 bool IsStringLocation, 2275 Range StringRange, 2276 ArrayRef<FixItHint> FixIt) { 2277 EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag, 2278 Loc, IsStringLocation, StringRange, FixIt); 2279} 2280 2281/// \brief If the format string is not within the funcion call, emit a note 2282/// so that the function call and string are in diagnostic messages. 2283/// 2284/// \param InFunctionCall if true, the format string is within the function 2285/// call and only one diagnostic message will be produced. Otherwise, an 2286/// extra note will be emitted pointing to location of the format string. 2287/// 2288/// \param ArgumentExpr the expression that is passed as the format string 2289/// argument in the function call. Used for getting locations when two 2290/// diagnostics are emitted. 2291/// 2292/// \param PDiag the callee should already have provided any strings for the 2293/// diagnostic message. This function only adds locations and fixits 2294/// to diagnostics. 2295/// 2296/// \param Loc primary location for diagnostic. If two diagnostics are 2297/// required, one will be at Loc and a new SourceLocation will be created for 2298/// the other one. 2299/// 2300/// \param IsStringLocation if true, Loc points to the format string should be 2301/// used for the note. Otherwise, Loc points to the argument list and will 2302/// be used with PDiag. 2303/// 2304/// \param StringRange some or all of the string to highlight. This is 2305/// templated so it can accept either a CharSourceRange or a SourceRange. 2306/// 2307/// \param FixIt optional fix it hint for the format string. 2308template<typename Range> 2309void CheckFormatHandler::EmitFormatDiagnostic(Sema &S, bool InFunctionCall, 2310 const Expr *ArgumentExpr, 2311 PartialDiagnostic PDiag, 2312 SourceLocation Loc, 2313 bool IsStringLocation, 2314 Range StringRange, 2315 ArrayRef<FixItHint> FixIt) { 2316 if (InFunctionCall) { 2317 const Sema::SemaDiagnosticBuilder &D = S.Diag(Loc, PDiag); 2318 D << StringRange; 2319 for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end(); 2320 I != E; ++I) { 2321 D << *I; 2322 } 2323 } else { 2324 S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag) 2325 << ArgumentExpr->getSourceRange(); 2326 2327 const Sema::SemaDiagnosticBuilder &Note = 2328 S.Diag(IsStringLocation ? Loc : StringRange.getBegin(), 2329 diag::note_format_string_defined); 2330 2331 Note << StringRange; 2332 for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end(); 2333 I != E; ++I) { 2334 Note << *I; 2335 } 2336 } 2337} 2338 2339//===--- CHECK: Printf format string checking ------------------------------===// 2340 2341namespace { 2342class CheckPrintfHandler : public CheckFormatHandler { 2343 bool ObjCContext; 2344public: 2345 CheckPrintfHandler(Sema &s, const StringLiteral *fexpr, 2346 const Expr *origFormatExpr, unsigned firstDataArg, 2347 unsigned numDataArgs, bool isObjC, 2348 const char *beg, bool hasVAListArg, 2349 Expr **Args, unsigned NumArgs, 2350 unsigned formatIdx, bool inFunctionCall, 2351 Sema::VariadicCallType CallType) 2352 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 2353 numDataArgs, beg, hasVAListArg, Args, NumArgs, 2354 formatIdx, inFunctionCall, CallType), ObjCContext(isObjC) 2355 {} 2356 2357 2358 bool HandleInvalidPrintfConversionSpecifier( 2359 const analyze_printf::PrintfSpecifier &FS, 2360 const char *startSpecifier, 2361 unsigned specifierLen); 2362 2363 bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS, 2364 const char *startSpecifier, 2365 unsigned specifierLen); 2366 bool checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 2367 const char *StartSpecifier, 2368 unsigned SpecifierLen, 2369 const Expr *E); 2370 2371 bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k, 2372 const char *startSpecifier, unsigned specifierLen); 2373 void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS, 2374 const analyze_printf::OptionalAmount &Amt, 2375 unsigned type, 2376 const char *startSpecifier, unsigned specifierLen); 2377 void HandleFlag(const analyze_printf::PrintfSpecifier &FS, 2378 const analyze_printf::OptionalFlag &flag, 2379 const char *startSpecifier, unsigned specifierLen); 2380 void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS, 2381 const analyze_printf::OptionalFlag &ignoredFlag, 2382 const analyze_printf::OptionalFlag &flag, 2383 const char *startSpecifier, unsigned specifierLen); 2384 bool checkForCStrMembers(const analyze_printf::ArgType &AT, 2385 const Expr *E, const CharSourceRange &CSR); 2386 2387}; 2388} 2389 2390bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier( 2391 const analyze_printf::PrintfSpecifier &FS, 2392 const char *startSpecifier, 2393 unsigned specifierLen) { 2394 const analyze_printf::PrintfConversionSpecifier &CS = 2395 FS.getConversionSpecifier(); 2396 2397 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 2398 getLocationOfByte(CS.getStart()), 2399 startSpecifier, specifierLen, 2400 CS.getStart(), CS.getLength()); 2401} 2402 2403bool CheckPrintfHandler::HandleAmount( 2404 const analyze_format_string::OptionalAmount &Amt, 2405 unsigned k, const char *startSpecifier, 2406 unsigned specifierLen) { 2407 2408 if (Amt.hasDataArgument()) { 2409 if (!HasVAListArg) { 2410 unsigned argIndex = Amt.getArgIndex(); 2411 if (argIndex >= NumDataArgs) { 2412 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg) 2413 << k, 2414 getLocationOfByte(Amt.getStart()), 2415 /*IsStringLocation*/true, 2416 getSpecifierRange(startSpecifier, specifierLen)); 2417 // Don't do any more checking. We will just emit 2418 // spurious errors. 2419 return false; 2420 } 2421 2422 // Type check the data argument. It should be an 'int'. 2423 // Although not in conformance with C99, we also allow the argument to be 2424 // an 'unsigned int' as that is a reasonably safe case. GCC also 2425 // doesn't emit a warning for that case. 2426 CoveredArgs.set(argIndex); 2427 const Expr *Arg = getDataArg(argIndex); 2428 if (!Arg) 2429 return false; 2430 2431 QualType T = Arg->getType(); 2432 2433 const analyze_printf::ArgType &AT = Amt.getArgType(S.Context); 2434 assert(AT.isValid()); 2435 2436 if (!AT.matchesType(S.Context, T)) { 2437 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type) 2438 << k << AT.getRepresentativeTypeName(S.Context) 2439 << T << Arg->getSourceRange(), 2440 getLocationOfByte(Amt.getStart()), 2441 /*IsStringLocation*/true, 2442 getSpecifierRange(startSpecifier, specifierLen)); 2443 // Don't do any more checking. We will just emit 2444 // spurious errors. 2445 return false; 2446 } 2447 } 2448 } 2449 return true; 2450} 2451 2452void CheckPrintfHandler::HandleInvalidAmount( 2453 const analyze_printf::PrintfSpecifier &FS, 2454 const analyze_printf::OptionalAmount &Amt, 2455 unsigned type, 2456 const char *startSpecifier, 2457 unsigned specifierLen) { 2458 const analyze_printf::PrintfConversionSpecifier &CS = 2459 FS.getConversionSpecifier(); 2460 2461 FixItHint fixit = 2462 Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant 2463 ? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(), 2464 Amt.getConstantLength())) 2465 : FixItHint(); 2466 2467 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount) 2468 << type << CS.toString(), 2469 getLocationOfByte(Amt.getStart()), 2470 /*IsStringLocation*/true, 2471 getSpecifierRange(startSpecifier, specifierLen), 2472 fixit); 2473} 2474 2475void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS, 2476 const analyze_printf::OptionalFlag &flag, 2477 const char *startSpecifier, 2478 unsigned specifierLen) { 2479 // Warn about pointless flag with a fixit removal. 2480 const analyze_printf::PrintfConversionSpecifier &CS = 2481 FS.getConversionSpecifier(); 2482 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag) 2483 << flag.toString() << CS.toString(), 2484 getLocationOfByte(flag.getPosition()), 2485 /*IsStringLocation*/true, 2486 getSpecifierRange(startSpecifier, specifierLen), 2487 FixItHint::CreateRemoval( 2488 getSpecifierRange(flag.getPosition(), 1))); 2489} 2490 2491void CheckPrintfHandler::HandleIgnoredFlag( 2492 const analyze_printf::PrintfSpecifier &FS, 2493 const analyze_printf::OptionalFlag &ignoredFlag, 2494 const analyze_printf::OptionalFlag &flag, 2495 const char *startSpecifier, 2496 unsigned specifierLen) { 2497 // Warn about ignored flag with a fixit removal. 2498 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag) 2499 << ignoredFlag.toString() << flag.toString(), 2500 getLocationOfByte(ignoredFlag.getPosition()), 2501 /*IsStringLocation*/true, 2502 getSpecifierRange(startSpecifier, specifierLen), 2503 FixItHint::CreateRemoval( 2504 getSpecifierRange(ignoredFlag.getPosition(), 1))); 2505} 2506 2507// Determines if the specified is a C++ class or struct containing 2508// a member with the specified name and kind (e.g. a CXXMethodDecl named 2509// "c_str()"). 2510template<typename MemberKind> 2511static llvm::SmallPtrSet<MemberKind*, 1> 2512CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) { 2513 const RecordType *RT = Ty->getAs<RecordType>(); 2514 llvm::SmallPtrSet<MemberKind*, 1> Results; 2515 2516 if (!RT) 2517 return Results; 2518 const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()); 2519 if (!RD) 2520 return Results; 2521 2522 LookupResult R(S, &S.PP.getIdentifierTable().get(Name), SourceLocation(), 2523 Sema::LookupMemberName); 2524 2525 // We just need to include all members of the right kind turned up by the 2526 // filter, at this point. 2527 if (S.LookupQualifiedName(R, RT->getDecl())) 2528 for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) { 2529 NamedDecl *decl = (*I)->getUnderlyingDecl(); 2530 if (MemberKind *FK = dyn_cast<MemberKind>(decl)) 2531 Results.insert(FK); 2532 } 2533 return Results; 2534} 2535 2536// Check if a (w)string was passed when a (w)char* was needed, and offer a 2537// better diagnostic if so. AT is assumed to be valid. 2538// Returns true when a c_str() conversion method is found. 2539bool CheckPrintfHandler::checkForCStrMembers( 2540 const analyze_printf::ArgType &AT, const Expr *E, 2541 const CharSourceRange &CSR) { 2542 typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet; 2543 2544 MethodSet Results = 2545 CXXRecordMembersNamed<CXXMethodDecl>("c_str", S, E->getType()); 2546 2547 for (MethodSet::iterator MI = Results.begin(), ME = Results.end(); 2548 MI != ME; ++MI) { 2549 const CXXMethodDecl *Method = *MI; 2550 if (Method->getNumParams() == 0 && 2551 AT.matchesType(S.Context, Method->getResultType())) { 2552 // FIXME: Suggest parens if the expression needs them. 2553 SourceLocation EndLoc = 2554 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()); 2555 S.Diag(E->getLocStart(), diag::note_printf_c_str) 2556 << "c_str()" 2557 << FixItHint::CreateInsertion(EndLoc, ".c_str()"); 2558 return true; 2559 } 2560 } 2561 2562 return false; 2563} 2564 2565bool 2566CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier 2567 &FS, 2568 const char *startSpecifier, 2569 unsigned specifierLen) { 2570 2571 using namespace analyze_format_string; 2572 using namespace analyze_printf; 2573 const PrintfConversionSpecifier &CS = FS.getConversionSpecifier(); 2574 2575 if (FS.consumesDataArgument()) { 2576 if (atFirstArg) { 2577 atFirstArg = false; 2578 usesPositionalArgs = FS.usesPositionalArg(); 2579 } 2580 else if (usesPositionalArgs != FS.usesPositionalArg()) { 2581 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 2582 startSpecifier, specifierLen); 2583 return false; 2584 } 2585 } 2586 2587 // First check if the field width, precision, and conversion specifier 2588 // have matching data arguments. 2589 if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0, 2590 startSpecifier, specifierLen)) { 2591 return false; 2592 } 2593 2594 if (!HandleAmount(FS.getPrecision(), /* precision */ 1, 2595 startSpecifier, specifierLen)) { 2596 return false; 2597 } 2598 2599 if (!CS.consumesDataArgument()) { 2600 // FIXME: Technically specifying a precision or field width here 2601 // makes no sense. Worth issuing a warning at some point. 2602 return true; 2603 } 2604 2605 // Consume the argument. 2606 unsigned argIndex = FS.getArgIndex(); 2607 if (argIndex < NumDataArgs) { 2608 // The check to see if the argIndex is valid will come later. 2609 // We set the bit here because we may exit early from this 2610 // function if we encounter some other error. 2611 CoveredArgs.set(argIndex); 2612 } 2613 2614 // Check for using an Objective-C specific conversion specifier 2615 // in a non-ObjC literal. 2616 if (!ObjCContext && CS.isObjCArg()) { 2617 return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier, 2618 specifierLen); 2619 } 2620 2621 // Check for invalid use of field width 2622 if (!FS.hasValidFieldWidth()) { 2623 HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0, 2624 startSpecifier, specifierLen); 2625 } 2626 2627 // Check for invalid use of precision 2628 if (!FS.hasValidPrecision()) { 2629 HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1, 2630 startSpecifier, specifierLen); 2631 } 2632 2633 // Check each flag does not conflict with any other component. 2634 if (!FS.hasValidThousandsGroupingPrefix()) 2635 HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen); 2636 if (!FS.hasValidLeadingZeros()) 2637 HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen); 2638 if (!FS.hasValidPlusPrefix()) 2639 HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen); 2640 if (!FS.hasValidSpacePrefix()) 2641 HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen); 2642 if (!FS.hasValidAlternativeForm()) 2643 HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen); 2644 if (!FS.hasValidLeftJustified()) 2645 HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen); 2646 2647 // Check that flags are not ignored by another flag 2648 if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+' 2649 HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(), 2650 startSpecifier, specifierLen); 2651 if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-' 2652 HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(), 2653 startSpecifier, specifierLen); 2654 2655 // Check the length modifier is valid with the given conversion specifier. 2656 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 2657 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 2658 diag::warn_format_nonsensical_length); 2659 else if (!FS.hasStandardLengthModifier()) 2660 HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen); 2661 else if (!FS.hasStandardLengthConversionCombination()) 2662 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 2663 diag::warn_format_non_standard_conversion_spec); 2664 2665 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 2666 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 2667 2668 // The remaining checks depend on the data arguments. 2669 if (HasVAListArg) 2670 return true; 2671 2672 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 2673 return false; 2674 2675 const Expr *Arg = getDataArg(argIndex); 2676 if (!Arg) 2677 return true; 2678 2679 return checkFormatExpr(FS, startSpecifier, specifierLen, Arg); 2680} 2681 2682static bool requiresParensToAddCast(const Expr *E) { 2683 // FIXME: We should have a general way to reason about operator 2684 // precedence and whether parens are actually needed here. 2685 // Take care of a few common cases where they aren't. 2686 const Expr *Inside = E->IgnoreImpCasts(); 2687 if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Inside)) 2688 Inside = POE->getSyntacticForm()->IgnoreImpCasts(); 2689 2690 switch (Inside->getStmtClass()) { 2691 case Stmt::ArraySubscriptExprClass: 2692 case Stmt::CallExprClass: 2693 case Stmt::DeclRefExprClass: 2694 case Stmt::MemberExprClass: 2695 case Stmt::ObjCIvarRefExprClass: 2696 case Stmt::ObjCMessageExprClass: 2697 case Stmt::ObjCPropertyRefExprClass: 2698 case Stmt::ParenExprClass: 2699 case Stmt::UnaryOperatorClass: 2700 return false; 2701 default: 2702 return true; 2703 } 2704} 2705 2706bool 2707CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 2708 const char *StartSpecifier, 2709 unsigned SpecifierLen, 2710 const Expr *E) { 2711 using namespace analyze_format_string; 2712 using namespace analyze_printf; 2713 // Now type check the data expression that matches the 2714 // format specifier. 2715 const analyze_printf::ArgType &AT = FS.getArgType(S.Context, 2716 ObjCContext); 2717 if (!AT.isValid()) 2718 return true; 2719 2720 QualType IntendedTy = E->getType(); 2721 if (AT.matchesType(S.Context, IntendedTy)) 2722 return true; 2723 2724 // Look through argument promotions for our error message's reported type. 2725 // This includes the integral and floating promotions, but excludes array 2726 // and function pointer decay; seeing that an argument intended to be a 2727 // string has type 'char [6]' is probably more confusing than 'char *'. 2728 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 2729 if (ICE->getCastKind() == CK_IntegralCast || 2730 ICE->getCastKind() == CK_FloatingCast) { 2731 E = ICE->getSubExpr(); 2732 IntendedTy = E->getType(); 2733 2734 // Check if we didn't match because of an implicit cast from a 'char' 2735 // or 'short' to an 'int'. This is done because printf is a varargs 2736 // function. 2737 if (ICE->getType() == S.Context.IntTy || 2738 ICE->getType() == S.Context.UnsignedIntTy) { 2739 // All further checking is done on the subexpression. 2740 if (AT.matchesType(S.Context, IntendedTy)) 2741 return true; 2742 } 2743 } 2744 } 2745 2746 if (S.Context.getTargetInfo().getTriple().isOSDarwin()) { 2747 // Special-case some of Darwin's platform-independence types. 2748 if (const TypedefType *UserTy = IntendedTy->getAs<TypedefType>()) { 2749 StringRef Name = UserTy->getDecl()->getName(); 2750 IntendedTy = llvm::StringSwitch<QualType>(Name) 2751 .Case("NSInteger", S.Context.LongTy) 2752 .Case("NSUInteger", S.Context.UnsignedLongTy) 2753 .Case("SInt32", S.Context.IntTy) 2754 .Case("UInt32", S.Context.UnsignedIntTy) 2755 .Default(IntendedTy); 2756 } 2757 } 2758 2759 // We may be able to offer a FixItHint if it is a supported type. 2760 PrintfSpecifier fixedFS = FS; 2761 bool success = fixedFS.fixType(IntendedTy, S.getLangOpts(), 2762 S.Context, ObjCContext); 2763 2764 if (success) { 2765 // Get the fix string from the fixed format specifier 2766 SmallString<16> buf; 2767 llvm::raw_svector_ostream os(buf); 2768 fixedFS.toString(os); 2769 2770 CharSourceRange SpecRange = getSpecifierRange(StartSpecifier, SpecifierLen); 2771 2772 if (IntendedTy != E->getType()) { 2773 // The canonical type for formatting this value is different from the 2774 // actual type of the expression. (This occurs, for example, with Darwin's 2775 // NSInteger on 32-bit platforms, where it is typedef'd as 'int', but 2776 // should be printed as 'long' for 64-bit compatibility.) 2777 // Rather than emitting a normal format/argument mismatch, we want to 2778 // add a cast to the recommended type (and correct the format string 2779 // if necessary). 2780 SmallString<16> CastBuf; 2781 llvm::raw_svector_ostream CastFix(CastBuf); 2782 CastFix << "("; 2783 IntendedTy.print(CastFix, S.Context.getPrintingPolicy()); 2784 CastFix << ")"; 2785 2786 SmallVector<FixItHint,4> Hints; 2787 if (!AT.matchesType(S.Context, IntendedTy)) 2788 Hints.push_back(FixItHint::CreateReplacement(SpecRange, os.str())); 2789 2790 if (const CStyleCastExpr *CCast = dyn_cast<CStyleCastExpr>(E)) { 2791 // If there's already a cast present, just replace it. 2792 SourceRange CastRange(CCast->getLParenLoc(), CCast->getRParenLoc()); 2793 Hints.push_back(FixItHint::CreateReplacement(CastRange, CastFix.str())); 2794 2795 } else if (!requiresParensToAddCast(E)) { 2796 // If the expression has high enough precedence, 2797 // just write the C-style cast. 2798 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 2799 CastFix.str())); 2800 } else { 2801 // Otherwise, add parens around the expression as well as the cast. 2802 CastFix << "("; 2803 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 2804 CastFix.str())); 2805 2806 SourceLocation After = S.PP.getLocForEndOfToken(E->getLocEnd()); 2807 Hints.push_back(FixItHint::CreateInsertion(After, ")")); 2808 } 2809 2810 // We extract the name from the typedef because we don't want to show 2811 // the underlying type in the diagnostic. 2812 const TypedefType *UserTy = cast<TypedefType>(E->getType()); 2813 StringRef Name = UserTy->getDecl()->getName(); 2814 2815 // Finally, emit the diagnostic. 2816 EmitFormatDiagnostic(S.PDiag(diag::warn_format_argument_needs_cast) 2817 << Name << IntendedTy 2818 << E->getSourceRange(), 2819 E->getLocStart(), /*IsStringLocation=*/false, 2820 SpecRange, Hints); 2821 } else { 2822 EmitFormatDiagnostic( 2823 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2824 << AT.getRepresentativeTypeName(S.Context) << IntendedTy 2825 << E->getSourceRange(), 2826 E->getLocStart(), 2827 /*IsStringLocation*/false, 2828 SpecRange, 2829 FixItHint::CreateReplacement(SpecRange, os.str())); 2830 } 2831 } else { 2832 const CharSourceRange &CSR = getSpecifierRange(StartSpecifier, 2833 SpecifierLen); 2834 // Since the warning for passing non-POD types to variadic functions 2835 // was deferred until now, we emit a warning for non-POD 2836 // arguments here. 2837 if (S.isValidVarArgType(E->getType()) == Sema::VAK_Invalid) { 2838 unsigned DiagKind; 2839 if (E->getType()->isObjCObjectType()) 2840 DiagKind = diag::err_cannot_pass_objc_interface_to_vararg_format; 2841 else 2842 DiagKind = diag::warn_non_pod_vararg_with_format_string; 2843 2844 EmitFormatDiagnostic( 2845 S.PDiag(DiagKind) 2846 << S.getLangOpts().CPlusPlus0x 2847 << E->getType() 2848 << CallType 2849 << AT.getRepresentativeTypeName(S.Context) 2850 << CSR 2851 << E->getSourceRange(), 2852 E->getLocStart(), /*IsStringLocation*/false, CSR); 2853 2854 checkForCStrMembers(AT, E, CSR); 2855 } else 2856 EmitFormatDiagnostic( 2857 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 2858 << AT.getRepresentativeTypeName(S.Context) << E->getType() 2859 << CSR 2860 << E->getSourceRange(), 2861 E->getLocStart(), /*IsStringLocation*/false, CSR); 2862 } 2863 2864 return true; 2865} 2866 2867//===--- CHECK: Scanf format string checking ------------------------------===// 2868 2869namespace { 2870class CheckScanfHandler : public CheckFormatHandler { 2871public: 2872 CheckScanfHandler(Sema &s, const StringLiteral *fexpr, 2873 const Expr *origFormatExpr, unsigned firstDataArg, 2874 unsigned numDataArgs, const char *beg, bool hasVAListArg, 2875 Expr **Args, unsigned NumArgs, 2876 unsigned formatIdx, bool inFunctionCall, 2877 Sema::VariadicCallType CallType) 2878 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 2879 numDataArgs, beg, hasVAListArg, 2880 Args, NumArgs, formatIdx, inFunctionCall, CallType) 2881 {} 2882 2883 bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS, 2884 const char *startSpecifier, 2885 unsigned specifierLen); 2886 2887 bool HandleInvalidScanfConversionSpecifier( 2888 const analyze_scanf::ScanfSpecifier &FS, 2889 const char *startSpecifier, 2890 unsigned specifierLen); 2891 2892 void HandleIncompleteScanList(const char *start, const char *end); 2893}; 2894} 2895 2896void CheckScanfHandler::HandleIncompleteScanList(const char *start, 2897 const char *end) { 2898 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete), 2899 getLocationOfByte(end), /*IsStringLocation*/true, 2900 getSpecifierRange(start, end - start)); 2901} 2902 2903bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier( 2904 const analyze_scanf::ScanfSpecifier &FS, 2905 const char *startSpecifier, 2906 unsigned specifierLen) { 2907 2908 const analyze_scanf::ScanfConversionSpecifier &CS = 2909 FS.getConversionSpecifier(); 2910 2911 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 2912 getLocationOfByte(CS.getStart()), 2913 startSpecifier, specifierLen, 2914 CS.getStart(), CS.getLength()); 2915} 2916 2917bool CheckScanfHandler::HandleScanfSpecifier( 2918 const analyze_scanf::ScanfSpecifier &FS, 2919 const char *startSpecifier, 2920 unsigned specifierLen) { 2921 2922 using namespace analyze_scanf; 2923 using namespace analyze_format_string; 2924 2925 const ScanfConversionSpecifier &CS = FS.getConversionSpecifier(); 2926 2927 // Handle case where '%' and '*' don't consume an argument. These shouldn't 2928 // be used to decide if we are using positional arguments consistently. 2929 if (FS.consumesDataArgument()) { 2930 if (atFirstArg) { 2931 atFirstArg = false; 2932 usesPositionalArgs = FS.usesPositionalArg(); 2933 } 2934 else if (usesPositionalArgs != FS.usesPositionalArg()) { 2935 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 2936 startSpecifier, specifierLen); 2937 return false; 2938 } 2939 } 2940 2941 // Check if the field with is non-zero. 2942 const OptionalAmount &Amt = FS.getFieldWidth(); 2943 if (Amt.getHowSpecified() == OptionalAmount::Constant) { 2944 if (Amt.getConstantAmount() == 0) { 2945 const CharSourceRange &R = getSpecifierRange(Amt.getStart(), 2946 Amt.getConstantLength()); 2947 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width), 2948 getLocationOfByte(Amt.getStart()), 2949 /*IsStringLocation*/true, R, 2950 FixItHint::CreateRemoval(R)); 2951 } 2952 } 2953 2954 if (!FS.consumesDataArgument()) { 2955 // FIXME: Technically specifying a precision or field width here 2956 // makes no sense. Worth issuing a warning at some point. 2957 return true; 2958 } 2959 2960 // Consume the argument. 2961 unsigned argIndex = FS.getArgIndex(); 2962 if (argIndex < NumDataArgs) { 2963 // The check to see if the argIndex is valid will come later. 2964 // We set the bit here because we may exit early from this 2965 // function if we encounter some other error. 2966 CoveredArgs.set(argIndex); 2967 } 2968 2969 // Check the length modifier is valid with the given conversion specifier. 2970 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 2971 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 2972 diag::warn_format_nonsensical_length); 2973 else if (!FS.hasStandardLengthModifier()) 2974 HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen); 2975 else if (!FS.hasStandardLengthConversionCombination()) 2976 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 2977 diag::warn_format_non_standard_conversion_spec); 2978 2979 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 2980 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 2981 2982 // The remaining checks depend on the data arguments. 2983 if (HasVAListArg) 2984 return true; 2985 2986 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 2987 return false; 2988 2989 // Check that the argument type matches the format specifier. 2990 const Expr *Ex = getDataArg(argIndex); 2991 if (!Ex) 2992 return true; 2993 2994 const analyze_format_string::ArgType &AT = FS.getArgType(S.Context); 2995 if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType())) { 2996 ScanfSpecifier fixedFS = FS; 2997 bool success = fixedFS.fixType(Ex->getType(), S.getLangOpts(), 2998 S.Context); 2999 3000 if (success) { 3001 // Get the fix string from the fixed format specifier. 3002 SmallString<128> buf; 3003 llvm::raw_svector_ostream os(buf); 3004 fixedFS.toString(os); 3005 3006 EmitFormatDiagnostic( 3007 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 3008 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() 3009 << Ex->getSourceRange(), 3010 Ex->getLocStart(), 3011 /*IsStringLocation*/false, 3012 getSpecifierRange(startSpecifier, specifierLen), 3013 FixItHint::CreateReplacement( 3014 getSpecifierRange(startSpecifier, specifierLen), 3015 os.str())); 3016 } else { 3017 EmitFormatDiagnostic( 3018 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 3019 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() 3020 << Ex->getSourceRange(), 3021 Ex->getLocStart(), 3022 /*IsStringLocation*/false, 3023 getSpecifierRange(startSpecifier, specifierLen)); 3024 } 3025 } 3026 3027 return true; 3028} 3029 3030void Sema::CheckFormatString(const StringLiteral *FExpr, 3031 const Expr *OrigFormatExpr, 3032 Expr **Args, unsigned NumArgs, 3033 bool HasVAListArg, unsigned format_idx, 3034 unsigned firstDataArg, FormatStringType Type, 3035 bool inFunctionCall, VariadicCallType CallType) { 3036 3037 // CHECK: is the format string a wide literal? 3038 if (!FExpr->isAscii() && !FExpr->isUTF8()) { 3039 CheckFormatHandler::EmitFormatDiagnostic( 3040 *this, inFunctionCall, Args[format_idx], 3041 PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(), 3042 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 3043 return; 3044 } 3045 3046 // Str - The format string. NOTE: this is NOT null-terminated! 3047 StringRef StrRef = FExpr->getString(); 3048 const char *Str = StrRef.data(); 3049 unsigned StrLen = StrRef.size(); 3050 const unsigned numDataArgs = NumArgs - firstDataArg; 3051 3052 // CHECK: empty format string? 3053 if (StrLen == 0 && numDataArgs > 0) { 3054 CheckFormatHandler::EmitFormatDiagnostic( 3055 *this, inFunctionCall, Args[format_idx], 3056 PDiag(diag::warn_empty_format_string), FExpr->getLocStart(), 3057 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 3058 return; 3059 } 3060 3061 if (Type == FST_Printf || Type == FST_NSString) { 3062 CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 3063 numDataArgs, (Type == FST_NSString), 3064 Str, HasVAListArg, Args, NumArgs, format_idx, 3065 inFunctionCall, CallType); 3066 3067 if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen, 3068 getLangOpts(), 3069 Context.getTargetInfo())) 3070 H.DoneProcessing(); 3071 } else if (Type == FST_Scanf) { 3072 CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, numDataArgs, 3073 Str, HasVAListArg, Args, NumArgs, format_idx, 3074 inFunctionCall, CallType); 3075 3076 if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen, 3077 getLangOpts(), 3078 Context.getTargetInfo())) 3079 H.DoneProcessing(); 3080 } // TODO: handle other formats 3081} 3082 3083//===--- CHECK: Standard memory functions ---------------------------------===// 3084 3085/// \brief Determine whether the given type is a dynamic class type (e.g., 3086/// whether it has a vtable). 3087static bool isDynamicClassType(QualType T) { 3088 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) 3089 if (CXXRecordDecl *Definition = Record->getDefinition()) 3090 if (Definition->isDynamicClass()) 3091 return true; 3092 3093 return false; 3094} 3095 3096/// \brief If E is a sizeof expression, returns its argument expression, 3097/// otherwise returns NULL. 3098static const Expr *getSizeOfExprArg(const Expr* E) { 3099 if (const UnaryExprOrTypeTraitExpr *SizeOf = 3100 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 3101 if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType()) 3102 return SizeOf->getArgumentExpr()->IgnoreParenImpCasts(); 3103 3104 return 0; 3105} 3106 3107/// \brief If E is a sizeof expression, returns its argument type. 3108static QualType getSizeOfArgType(const Expr* E) { 3109 if (const UnaryExprOrTypeTraitExpr *SizeOf = 3110 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 3111 if (SizeOf->getKind() == clang::UETT_SizeOf) 3112 return SizeOf->getTypeOfArgument(); 3113 3114 return QualType(); 3115} 3116 3117/// \brief Check for dangerous or invalid arguments to memset(). 3118/// 3119/// This issues warnings on known problematic, dangerous or unspecified 3120/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp' 3121/// function calls. 3122/// 3123/// \param Call The call expression to diagnose. 3124void Sema::CheckMemaccessArguments(const CallExpr *Call, 3125 unsigned BId, 3126 IdentifierInfo *FnName) { 3127 assert(BId != 0); 3128 3129 // It is possible to have a non-standard definition of memset. Validate 3130 // we have enough arguments, and if not, abort further checking. 3131 unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3); 3132 if (Call->getNumArgs() < ExpectedNumArgs) 3133 return; 3134 3135 unsigned LastArg = (BId == Builtin::BImemset || 3136 BId == Builtin::BIstrndup ? 1 : 2); 3137 unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2); 3138 const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts(); 3139 3140 // We have special checking when the length is a sizeof expression. 3141 QualType SizeOfArgTy = getSizeOfArgType(LenExpr); 3142 const Expr *SizeOfArg = getSizeOfExprArg(LenExpr); 3143 llvm::FoldingSetNodeID SizeOfArgID; 3144 3145 for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) { 3146 const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts(); 3147 SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange(); 3148 3149 QualType DestTy = Dest->getType(); 3150 if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) { 3151 QualType PointeeTy = DestPtrTy->getPointeeType(); 3152 3153 // Never warn about void type pointers. This can be used to suppress 3154 // false positives. 3155 if (PointeeTy->isVoidType()) 3156 continue; 3157 3158 // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by 3159 // actually comparing the expressions for equality. Because computing the 3160 // expression IDs can be expensive, we only do this if the diagnostic is 3161 // enabled. 3162 if (SizeOfArg && 3163 Diags.getDiagnosticLevel(diag::warn_sizeof_pointer_expr_memaccess, 3164 SizeOfArg->getExprLoc())) { 3165 // We only compute IDs for expressions if the warning is enabled, and 3166 // cache the sizeof arg's ID. 3167 if (SizeOfArgID == llvm::FoldingSetNodeID()) 3168 SizeOfArg->Profile(SizeOfArgID, Context, true); 3169 llvm::FoldingSetNodeID DestID; 3170 Dest->Profile(DestID, Context, true); 3171 if (DestID == SizeOfArgID) { 3172 // TODO: For strncpy() and friends, this could suggest sizeof(dst) 3173 // over sizeof(src) as well. 3174 unsigned ActionIdx = 0; // Default is to suggest dereferencing. 3175 StringRef ReadableName = FnName->getName(); 3176 3177 if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest)) 3178 if (UnaryOp->getOpcode() == UO_AddrOf) 3179 ActionIdx = 1; // If its an address-of operator, just remove it. 3180 if (Context.getTypeSize(PointeeTy) == Context.getCharWidth()) 3181 ActionIdx = 2; // If the pointee's size is sizeof(char), 3182 // suggest an explicit length. 3183 3184 // If the function is defined as a builtin macro, do not show macro 3185 // expansion. 3186 SourceLocation SL = SizeOfArg->getExprLoc(); 3187 SourceRange DSR = Dest->getSourceRange(); 3188 SourceRange SSR = SizeOfArg->getSourceRange(); 3189 SourceManager &SM = PP.getSourceManager(); 3190 3191 if (SM.isMacroArgExpansion(SL)) { 3192 ReadableName = Lexer::getImmediateMacroName(SL, SM, LangOpts); 3193 SL = SM.getSpellingLoc(SL); 3194 DSR = SourceRange(SM.getSpellingLoc(DSR.getBegin()), 3195 SM.getSpellingLoc(DSR.getEnd())); 3196 SSR = SourceRange(SM.getSpellingLoc(SSR.getBegin()), 3197 SM.getSpellingLoc(SSR.getEnd())); 3198 } 3199 3200 DiagRuntimeBehavior(SL, SizeOfArg, 3201 PDiag(diag::warn_sizeof_pointer_expr_memaccess) 3202 << ReadableName 3203 << PointeeTy 3204 << DestTy 3205 << DSR 3206 << SSR); 3207 DiagRuntimeBehavior(SL, SizeOfArg, 3208 PDiag(diag::warn_sizeof_pointer_expr_memaccess_note) 3209 << ActionIdx 3210 << SSR); 3211 3212 break; 3213 } 3214 } 3215 3216 // Also check for cases where the sizeof argument is the exact same 3217 // type as the memory argument, and where it points to a user-defined 3218 // record type. 3219 if (SizeOfArgTy != QualType()) { 3220 if (PointeeTy->isRecordType() && 3221 Context.typesAreCompatible(SizeOfArgTy, DestTy)) { 3222 DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest, 3223 PDiag(diag::warn_sizeof_pointer_type_memaccess) 3224 << FnName << SizeOfArgTy << ArgIdx 3225 << PointeeTy << Dest->getSourceRange() 3226 << LenExpr->getSourceRange()); 3227 break; 3228 } 3229 } 3230 3231 // Always complain about dynamic classes. 3232 if (isDynamicClassType(PointeeTy)) { 3233 3234 unsigned OperationType = 0; 3235 // "overwritten" if we're warning about the destination for any call 3236 // but memcmp; otherwise a verb appropriate to the call. 3237 if (ArgIdx != 0 || BId == Builtin::BImemcmp) { 3238 if (BId == Builtin::BImemcpy) 3239 OperationType = 1; 3240 else if(BId == Builtin::BImemmove) 3241 OperationType = 2; 3242 else if (BId == Builtin::BImemcmp) 3243 OperationType = 3; 3244 } 3245 3246 DiagRuntimeBehavior( 3247 Dest->getExprLoc(), Dest, 3248 PDiag(diag::warn_dyn_class_memaccess) 3249 << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx) 3250 << FnName << PointeeTy 3251 << OperationType 3252 << Call->getCallee()->getSourceRange()); 3253 } else if (PointeeTy.hasNonTrivialObjCLifetime() && 3254 BId != Builtin::BImemset) 3255 DiagRuntimeBehavior( 3256 Dest->getExprLoc(), Dest, 3257 PDiag(diag::warn_arc_object_memaccess) 3258 << ArgIdx << FnName << PointeeTy 3259 << Call->getCallee()->getSourceRange()); 3260 else 3261 continue; 3262 3263 DiagRuntimeBehavior( 3264 Dest->getExprLoc(), Dest, 3265 PDiag(diag::note_bad_memaccess_silence) 3266 << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)")); 3267 break; 3268 } 3269 } 3270} 3271 3272// A little helper routine: ignore addition and subtraction of integer literals. 3273// This intentionally does not ignore all integer constant expressions because 3274// we don't want to remove sizeof(). 3275static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) { 3276 Ex = Ex->IgnoreParenCasts(); 3277 3278 for (;;) { 3279 const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex); 3280 if (!BO || !BO->isAdditiveOp()) 3281 break; 3282 3283 const Expr *RHS = BO->getRHS()->IgnoreParenCasts(); 3284 const Expr *LHS = BO->getLHS()->IgnoreParenCasts(); 3285 3286 if (isa<IntegerLiteral>(RHS)) 3287 Ex = LHS; 3288 else if (isa<IntegerLiteral>(LHS)) 3289 Ex = RHS; 3290 else 3291 break; 3292 } 3293 3294 return Ex; 3295} 3296 3297static bool isConstantSizeArrayWithMoreThanOneElement(QualType Ty, 3298 ASTContext &Context) { 3299 // Only handle constant-sized or VLAs, but not flexible members. 3300 if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(Ty)) { 3301 // Only issue the FIXIT for arrays of size > 1. 3302 if (CAT->getSize().getSExtValue() <= 1) 3303 return false; 3304 } else if (!Ty->isVariableArrayType()) { 3305 return false; 3306 } 3307 return true; 3308} 3309 3310// Warn if the user has made the 'size' argument to strlcpy or strlcat 3311// be the size of the source, instead of the destination. 3312void Sema::CheckStrlcpycatArguments(const CallExpr *Call, 3313 IdentifierInfo *FnName) { 3314 3315 // Don't crash if the user has the wrong number of arguments 3316 if (Call->getNumArgs() != 3) 3317 return; 3318 3319 const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context); 3320 const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context); 3321 const Expr *CompareWithSrc = NULL; 3322 3323 // Look for 'strlcpy(dst, x, sizeof(x))' 3324 if (const Expr *Ex = getSizeOfExprArg(SizeArg)) 3325 CompareWithSrc = Ex; 3326 else { 3327 // Look for 'strlcpy(dst, x, strlen(x))' 3328 if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) { 3329 if (SizeCall->isBuiltinCall() == Builtin::BIstrlen 3330 && SizeCall->getNumArgs() == 1) 3331 CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context); 3332 } 3333 } 3334 3335 if (!CompareWithSrc) 3336 return; 3337 3338 // Determine if the argument to sizeof/strlen is equal to the source 3339 // argument. In principle there's all kinds of things you could do 3340 // here, for instance creating an == expression and evaluating it with 3341 // EvaluateAsBooleanCondition, but this uses a more direct technique: 3342 const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg); 3343 if (!SrcArgDRE) 3344 return; 3345 3346 const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc); 3347 if (!CompareWithSrcDRE || 3348 SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl()) 3349 return; 3350 3351 const Expr *OriginalSizeArg = Call->getArg(2); 3352 Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size) 3353 << OriginalSizeArg->getSourceRange() << FnName; 3354 3355 // Output a FIXIT hint if the destination is an array (rather than a 3356 // pointer to an array). This could be enhanced to handle some 3357 // pointers if we know the actual size, like if DstArg is 'array+2' 3358 // we could say 'sizeof(array)-2'. 3359 const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts(); 3360 if (!isConstantSizeArrayWithMoreThanOneElement(DstArg->getType(), Context)) 3361 return; 3362 3363 SmallString<128> sizeString; 3364 llvm::raw_svector_ostream OS(sizeString); 3365 OS << "sizeof("; 3366 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3367 OS << ")"; 3368 3369 Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size) 3370 << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(), 3371 OS.str()); 3372} 3373 3374/// Check if two expressions refer to the same declaration. 3375static bool referToTheSameDecl(const Expr *E1, const Expr *E2) { 3376 if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1)) 3377 if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2)) 3378 return D1->getDecl() == D2->getDecl(); 3379 return false; 3380} 3381 3382static const Expr *getStrlenExprArg(const Expr *E) { 3383 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 3384 const FunctionDecl *FD = CE->getDirectCallee(); 3385 if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen) 3386 return 0; 3387 return CE->getArg(0)->IgnoreParenCasts(); 3388 } 3389 return 0; 3390} 3391 3392// Warn on anti-patterns as the 'size' argument to strncat. 3393// The correct size argument should look like following: 3394// strncat(dst, src, sizeof(dst) - strlen(dest) - 1); 3395void Sema::CheckStrncatArguments(const CallExpr *CE, 3396 IdentifierInfo *FnName) { 3397 // Don't crash if the user has the wrong number of arguments. 3398 if (CE->getNumArgs() < 3) 3399 return; 3400 const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts(); 3401 const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts(); 3402 const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts(); 3403 3404 // Identify common expressions, which are wrongly used as the size argument 3405 // to strncat and may lead to buffer overflows. 3406 unsigned PatternType = 0; 3407 if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) { 3408 // - sizeof(dst) 3409 if (referToTheSameDecl(SizeOfArg, DstArg)) 3410 PatternType = 1; 3411 // - sizeof(src) 3412 else if (referToTheSameDecl(SizeOfArg, SrcArg)) 3413 PatternType = 2; 3414 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) { 3415 if (BE->getOpcode() == BO_Sub) { 3416 const Expr *L = BE->getLHS()->IgnoreParenCasts(); 3417 const Expr *R = BE->getRHS()->IgnoreParenCasts(); 3418 // - sizeof(dst) - strlen(dst) 3419 if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) && 3420 referToTheSameDecl(DstArg, getStrlenExprArg(R))) 3421 PatternType = 1; 3422 // - sizeof(src) - (anything) 3423 else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L))) 3424 PatternType = 2; 3425 } 3426 } 3427 3428 if (PatternType == 0) 3429 return; 3430 3431 // Generate the diagnostic. 3432 SourceLocation SL = LenArg->getLocStart(); 3433 SourceRange SR = LenArg->getSourceRange(); 3434 SourceManager &SM = PP.getSourceManager(); 3435 3436 // If the function is defined as a builtin macro, do not show macro expansion. 3437 if (SM.isMacroArgExpansion(SL)) { 3438 SL = SM.getSpellingLoc(SL); 3439 SR = SourceRange(SM.getSpellingLoc(SR.getBegin()), 3440 SM.getSpellingLoc(SR.getEnd())); 3441 } 3442 3443 // Check if the destination is an array (rather than a pointer to an array). 3444 QualType DstTy = DstArg->getType(); 3445 bool isKnownSizeArray = isConstantSizeArrayWithMoreThanOneElement(DstTy, 3446 Context); 3447 if (!isKnownSizeArray) { 3448 if (PatternType == 1) 3449 Diag(SL, diag::warn_strncat_wrong_size) << SR; 3450 else 3451 Diag(SL, diag::warn_strncat_src_size) << SR; 3452 return; 3453 } 3454 3455 if (PatternType == 1) 3456 Diag(SL, diag::warn_strncat_large_size) << SR; 3457 else 3458 Diag(SL, diag::warn_strncat_src_size) << SR; 3459 3460 SmallString<128> sizeString; 3461 llvm::raw_svector_ostream OS(sizeString); 3462 OS << "sizeof("; 3463 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3464 OS << ") - "; 3465 OS << "strlen("; 3466 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3467 OS << ") - 1"; 3468 3469 Diag(SL, diag::note_strncat_wrong_size) 3470 << FixItHint::CreateReplacement(SR, OS.str()); 3471} 3472 3473//===--- CHECK: Return Address of Stack Variable --------------------------===// 3474 3475static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3476 Decl *ParentDecl); 3477static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars, 3478 Decl *ParentDecl); 3479 3480/// CheckReturnStackAddr - Check if a return statement returns the address 3481/// of a stack variable. 3482void 3483Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType, 3484 SourceLocation ReturnLoc) { 3485 3486 Expr *stackE = 0; 3487 SmallVector<DeclRefExpr *, 8> refVars; 3488 3489 // Perform checking for returned stack addresses, local blocks, 3490 // label addresses or references to temporaries. 3491 if (lhsType->isPointerType() || 3492 (!getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) { 3493 stackE = EvalAddr(RetValExp, refVars, /*ParentDecl=*/0); 3494 } else if (lhsType->isReferenceType()) { 3495 stackE = EvalVal(RetValExp, refVars, /*ParentDecl=*/0); 3496 } 3497 3498 if (stackE == 0) 3499 return; // Nothing suspicious was found. 3500 3501 SourceLocation diagLoc; 3502 SourceRange diagRange; 3503 if (refVars.empty()) { 3504 diagLoc = stackE->getLocStart(); 3505 diagRange = stackE->getSourceRange(); 3506 } else { 3507 // We followed through a reference variable. 'stackE' contains the 3508 // problematic expression but we will warn at the return statement pointing 3509 // at the reference variable. We will later display the "trail" of 3510 // reference variables using notes. 3511 diagLoc = refVars[0]->getLocStart(); 3512 diagRange = refVars[0]->getSourceRange(); 3513 } 3514 3515 if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var. 3516 Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref 3517 : diag::warn_ret_stack_addr) 3518 << DR->getDecl()->getDeclName() << diagRange; 3519 } else if (isa<BlockExpr>(stackE)) { // local block. 3520 Diag(diagLoc, diag::err_ret_local_block) << diagRange; 3521 } else if (isa<AddrLabelExpr>(stackE)) { // address of label. 3522 Diag(diagLoc, diag::warn_ret_addr_label) << diagRange; 3523 } else { // local temporary. 3524 Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref 3525 : diag::warn_ret_local_temp_addr) 3526 << diagRange; 3527 } 3528 3529 // Display the "trail" of reference variables that we followed until we 3530 // found the problematic expression using notes. 3531 for (unsigned i = 0, e = refVars.size(); i != e; ++i) { 3532 VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl()); 3533 // If this var binds to another reference var, show the range of the next 3534 // var, otherwise the var binds to the problematic expression, in which case 3535 // show the range of the expression. 3536 SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange() 3537 : stackE->getSourceRange(); 3538 Diag(VD->getLocation(), diag::note_ref_var_local_bind) 3539 << VD->getDeclName() << range; 3540 } 3541} 3542 3543/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that 3544/// check if the expression in a return statement evaluates to an address 3545/// to a location on the stack, a local block, an address of a label, or a 3546/// reference to local temporary. The recursion is used to traverse the 3547/// AST of the return expression, with recursion backtracking when we 3548/// encounter a subexpression that (1) clearly does not lead to one of the 3549/// above problematic expressions (2) is something we cannot determine leads to 3550/// a problematic expression based on such local checking. 3551/// 3552/// Both EvalAddr and EvalVal follow through reference variables to evaluate 3553/// the expression that they point to. Such variables are added to the 3554/// 'refVars' vector so that we know what the reference variable "trail" was. 3555/// 3556/// EvalAddr processes expressions that are pointers that are used as 3557/// references (and not L-values). EvalVal handles all other values. 3558/// At the base case of the recursion is a check for the above problematic 3559/// expressions. 3560/// 3561/// This implementation handles: 3562/// 3563/// * pointer-to-pointer casts 3564/// * implicit conversions from array references to pointers 3565/// * taking the address of fields 3566/// * arbitrary interplay between "&" and "*" operators 3567/// * pointer arithmetic from an address of a stack variable 3568/// * taking the address of an array element where the array is on the stack 3569static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3570 Decl *ParentDecl) { 3571 if (E->isTypeDependent()) 3572 return NULL; 3573 3574 // We should only be called for evaluating pointer expressions. 3575 assert((E->getType()->isAnyPointerType() || 3576 E->getType()->isBlockPointerType() || 3577 E->getType()->isObjCQualifiedIdType()) && 3578 "EvalAddr only works on pointers"); 3579 3580 E = E->IgnoreParens(); 3581 3582 // Our "symbolic interpreter" is just a dispatch off the currently 3583 // viewed AST node. We then recursively traverse the AST by calling 3584 // EvalAddr and EvalVal appropriately. 3585 switch (E->getStmtClass()) { 3586 case Stmt::DeclRefExprClass: { 3587 DeclRefExpr *DR = cast<DeclRefExpr>(E); 3588 3589 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) 3590 // If this is a reference variable, follow through to the expression that 3591 // it points to. 3592 if (V->hasLocalStorage() && 3593 V->getType()->isReferenceType() && V->hasInit()) { 3594 // Add the reference variable to the "trail". 3595 refVars.push_back(DR); 3596 return EvalAddr(V->getInit(), refVars, ParentDecl); 3597 } 3598 3599 return NULL; 3600 } 3601 3602 case Stmt::UnaryOperatorClass: { 3603 // The only unary operator that make sense to handle here 3604 // is AddrOf. All others don't make sense as pointers. 3605 UnaryOperator *U = cast<UnaryOperator>(E); 3606 3607 if (U->getOpcode() == UO_AddrOf) 3608 return EvalVal(U->getSubExpr(), refVars, ParentDecl); 3609 else 3610 return NULL; 3611 } 3612 3613 case Stmt::BinaryOperatorClass: { 3614 // Handle pointer arithmetic. All other binary operators are not valid 3615 // in this context. 3616 BinaryOperator *B = cast<BinaryOperator>(E); 3617 BinaryOperatorKind op = B->getOpcode(); 3618 3619 if (op != BO_Add && op != BO_Sub) 3620 return NULL; 3621 3622 Expr *Base = B->getLHS(); 3623 3624 // Determine which argument is the real pointer base. It could be 3625 // the RHS argument instead of the LHS. 3626 if (!Base->getType()->isPointerType()) Base = B->getRHS(); 3627 3628 assert (Base->getType()->isPointerType()); 3629 return EvalAddr(Base, refVars, ParentDecl); 3630 } 3631 3632 // For conditional operators we need to see if either the LHS or RHS are 3633 // valid DeclRefExpr*s. If one of them is valid, we return it. 3634 case Stmt::ConditionalOperatorClass: { 3635 ConditionalOperator *C = cast<ConditionalOperator>(E); 3636 3637 // Handle the GNU extension for missing LHS. 3638 if (Expr *lhsExpr = C->getLHS()) { 3639 // In C++, we can have a throw-expression, which has 'void' type. 3640 if (!lhsExpr->getType()->isVoidType()) 3641 if (Expr* LHS = EvalAddr(lhsExpr, refVars, ParentDecl)) 3642 return LHS; 3643 } 3644 3645 // In C++, we can have a throw-expression, which has 'void' type. 3646 if (C->getRHS()->getType()->isVoidType()) 3647 return NULL; 3648 3649 return EvalAddr(C->getRHS(), refVars, ParentDecl); 3650 } 3651 3652 case Stmt::BlockExprClass: 3653 if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures()) 3654 return E; // local block. 3655 return NULL; 3656 3657 case Stmt::AddrLabelExprClass: 3658 return E; // address of label. 3659 3660 case Stmt::ExprWithCleanupsClass: 3661 return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars, 3662 ParentDecl); 3663 3664 // For casts, we need to handle conversions from arrays to 3665 // pointer values, and pointer-to-pointer conversions. 3666 case Stmt::ImplicitCastExprClass: 3667 case Stmt::CStyleCastExprClass: 3668 case Stmt::CXXFunctionalCastExprClass: 3669 case Stmt::ObjCBridgedCastExprClass: 3670 case Stmt::CXXStaticCastExprClass: 3671 case Stmt::CXXDynamicCastExprClass: 3672 case Stmt::CXXConstCastExprClass: 3673 case Stmt::CXXReinterpretCastExprClass: { 3674 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr(); 3675 switch (cast<CastExpr>(E)->getCastKind()) { 3676 case CK_BitCast: 3677 case CK_LValueToRValue: 3678 case CK_NoOp: 3679 case CK_BaseToDerived: 3680 case CK_DerivedToBase: 3681 case CK_UncheckedDerivedToBase: 3682 case CK_Dynamic: 3683 case CK_CPointerToObjCPointerCast: 3684 case CK_BlockPointerToObjCPointerCast: 3685 case CK_AnyPointerToBlockPointerCast: 3686 return EvalAddr(SubExpr, refVars, ParentDecl); 3687 3688 case CK_ArrayToPointerDecay: 3689 return EvalVal(SubExpr, refVars, ParentDecl); 3690 3691 default: 3692 return 0; 3693 } 3694 } 3695 3696 case Stmt::MaterializeTemporaryExprClass: 3697 if (Expr *Result = EvalAddr( 3698 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 3699 refVars, ParentDecl)) 3700 return Result; 3701 3702 return E; 3703 3704 // Everything else: we simply don't reason about them. 3705 default: 3706 return NULL; 3707 } 3708} 3709 3710 3711/// EvalVal - This function is complements EvalAddr in the mutual recursion. 3712/// See the comments for EvalAddr for more details. 3713static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3714 Decl *ParentDecl) { 3715do { 3716 // We should only be called for evaluating non-pointer expressions, or 3717 // expressions with a pointer type that are not used as references but instead 3718 // are l-values (e.g., DeclRefExpr with a pointer type). 3719 3720 // Our "symbolic interpreter" is just a dispatch off the currently 3721 // viewed AST node. We then recursively traverse the AST by calling 3722 // EvalAddr and EvalVal appropriately. 3723 3724 E = E->IgnoreParens(); 3725 switch (E->getStmtClass()) { 3726 case Stmt::ImplicitCastExprClass: { 3727 ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E); 3728 if (IE->getValueKind() == VK_LValue) { 3729 E = IE->getSubExpr(); 3730 continue; 3731 } 3732 return NULL; 3733 } 3734 3735 case Stmt::ExprWithCleanupsClass: 3736 return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,ParentDecl); 3737 3738 case Stmt::DeclRefExprClass: { 3739 // When we hit a DeclRefExpr we are looking at code that refers to a 3740 // variable's name. If it's not a reference variable we check if it has 3741 // local storage within the function, and if so, return the expression. 3742 DeclRefExpr *DR = cast<DeclRefExpr>(E); 3743 3744 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) { 3745 // Check if it refers to itself, e.g. "int& i = i;". 3746 if (V == ParentDecl) 3747 return DR; 3748 3749 if (V->hasLocalStorage()) { 3750 if (!V->getType()->isReferenceType()) 3751 return DR; 3752 3753 // Reference variable, follow through to the expression that 3754 // it points to. 3755 if (V->hasInit()) { 3756 // Add the reference variable to the "trail". 3757 refVars.push_back(DR); 3758 return EvalVal(V->getInit(), refVars, V); 3759 } 3760 } 3761 } 3762 3763 return NULL; 3764 } 3765 3766 case Stmt::UnaryOperatorClass: { 3767 // The only unary operator that make sense to handle here 3768 // is Deref. All others don't resolve to a "name." This includes 3769 // handling all sorts of rvalues passed to a unary operator. 3770 UnaryOperator *U = cast<UnaryOperator>(E); 3771 3772 if (U->getOpcode() == UO_Deref) 3773 return EvalAddr(U->getSubExpr(), refVars, ParentDecl); 3774 3775 return NULL; 3776 } 3777 3778 case Stmt::ArraySubscriptExprClass: { 3779 // Array subscripts are potential references to data on the stack. We 3780 // retrieve the DeclRefExpr* for the array variable if it indeed 3781 // has local storage. 3782 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars,ParentDecl); 3783 } 3784 3785 case Stmt::ConditionalOperatorClass: { 3786 // For conditional operators we need to see if either the LHS or RHS are 3787 // non-NULL Expr's. If one is non-NULL, we return it. 3788 ConditionalOperator *C = cast<ConditionalOperator>(E); 3789 3790 // Handle the GNU extension for missing LHS. 3791 if (Expr *lhsExpr = C->getLHS()) 3792 if (Expr *LHS = EvalVal(lhsExpr, refVars, ParentDecl)) 3793 return LHS; 3794 3795 return EvalVal(C->getRHS(), refVars, ParentDecl); 3796 } 3797 3798 // Accesses to members are potential references to data on the stack. 3799 case Stmt::MemberExprClass: { 3800 MemberExpr *M = cast<MemberExpr>(E); 3801 3802 // Check for indirect access. We only want direct field accesses. 3803 if (M->isArrow()) 3804 return NULL; 3805 3806 // Check whether the member type is itself a reference, in which case 3807 // we're not going to refer to the member, but to what the member refers to. 3808 if (M->getMemberDecl()->getType()->isReferenceType()) 3809 return NULL; 3810 3811 return EvalVal(M->getBase(), refVars, ParentDecl); 3812 } 3813 3814 case Stmt::MaterializeTemporaryExprClass: 3815 if (Expr *Result = EvalVal( 3816 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 3817 refVars, ParentDecl)) 3818 return Result; 3819 3820 return E; 3821 3822 default: 3823 // Check that we don't return or take the address of a reference to a 3824 // temporary. This is only useful in C++. 3825 if (!E->isTypeDependent() && E->isRValue()) 3826 return E; 3827 3828 // Everything else: we simply don't reason about them. 3829 return NULL; 3830 } 3831} while (true); 3832} 3833 3834//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===// 3835 3836/// Check for comparisons of floating point operands using != and ==. 3837/// Issue a warning if these are no self-comparisons, as they are not likely 3838/// to do what the programmer intended. 3839void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) { 3840 Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts(); 3841 Expr* RightExprSansParen = RHS->IgnoreParenImpCasts(); 3842 3843 // Special case: check for x == x (which is OK). 3844 // Do not emit warnings for such cases. 3845 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen)) 3846 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen)) 3847 if (DRL->getDecl() == DRR->getDecl()) 3848 return; 3849 3850 3851 // Special case: check for comparisons against literals that can be exactly 3852 // represented by APFloat. In such cases, do not emit a warning. This 3853 // is a heuristic: often comparison against such literals are used to 3854 // detect if a value in a variable has not changed. This clearly can 3855 // lead to false negatives. 3856 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) { 3857 if (FLL->isExact()) 3858 return; 3859 } else 3860 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)) 3861 if (FLR->isExact()) 3862 return; 3863 3864 // Check for comparisons with builtin types. 3865 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen)) 3866 if (CL->isBuiltinCall()) 3867 return; 3868 3869 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen)) 3870 if (CR->isBuiltinCall()) 3871 return; 3872 3873 // Emit the diagnostic. 3874 Diag(Loc, diag::warn_floatingpoint_eq) 3875 << LHS->getSourceRange() << RHS->getSourceRange(); 3876} 3877 3878//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===// 3879//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===// 3880 3881namespace { 3882 3883/// Structure recording the 'active' range of an integer-valued 3884/// expression. 3885struct IntRange { 3886 /// The number of bits active in the int. 3887 unsigned Width; 3888 3889 /// True if the int is known not to have negative values. 3890 bool NonNegative; 3891 3892 IntRange(unsigned Width, bool NonNegative) 3893 : Width(Width), NonNegative(NonNegative) 3894 {} 3895 3896 /// Returns the range of the bool type. 3897 static IntRange forBoolType() { 3898 return IntRange(1, true); 3899 } 3900 3901 /// Returns the range of an opaque value of the given integral type. 3902 static IntRange forValueOfType(ASTContext &C, QualType T) { 3903 return forValueOfCanonicalType(C, 3904 T->getCanonicalTypeInternal().getTypePtr()); 3905 } 3906 3907 /// Returns the range of an opaque value of a canonical integral type. 3908 static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) { 3909 assert(T->isCanonicalUnqualified()); 3910 3911 if (const VectorType *VT = dyn_cast<VectorType>(T)) 3912 T = VT->getElementType().getTypePtr(); 3913 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 3914 T = CT->getElementType().getTypePtr(); 3915 3916 // For enum types, use the known bit width of the enumerators. 3917 if (const EnumType *ET = dyn_cast<EnumType>(T)) { 3918 EnumDecl *Enum = ET->getDecl(); 3919 if (!Enum->isCompleteDefinition()) 3920 return IntRange(C.getIntWidth(QualType(T, 0)), false); 3921 3922 unsigned NumPositive = Enum->getNumPositiveBits(); 3923 unsigned NumNegative = Enum->getNumNegativeBits(); 3924 3925 if (NumNegative == 0) 3926 return IntRange(NumPositive, true/*NonNegative*/); 3927 else 3928 return IntRange(std::max(NumPositive + 1, NumNegative), 3929 false/*NonNegative*/); 3930 } 3931 3932 const BuiltinType *BT = cast<BuiltinType>(T); 3933 assert(BT->isInteger()); 3934 3935 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 3936 } 3937 3938 /// Returns the "target" range of a canonical integral type, i.e. 3939 /// the range of values expressible in the type. 3940 /// 3941 /// This matches forValueOfCanonicalType except that enums have the 3942 /// full range of their type, not the range of their enumerators. 3943 static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) { 3944 assert(T->isCanonicalUnqualified()); 3945 3946 if (const VectorType *VT = dyn_cast<VectorType>(T)) 3947 T = VT->getElementType().getTypePtr(); 3948 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 3949 T = CT->getElementType().getTypePtr(); 3950 if (const EnumType *ET = dyn_cast<EnumType>(T)) 3951 T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr(); 3952 3953 const BuiltinType *BT = cast<BuiltinType>(T); 3954 assert(BT->isInteger()); 3955 3956 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 3957 } 3958 3959 /// Returns the supremum of two ranges: i.e. their conservative merge. 3960 static IntRange join(IntRange L, IntRange R) { 3961 return IntRange(std::max(L.Width, R.Width), 3962 L.NonNegative && R.NonNegative); 3963 } 3964 3965 /// Returns the infinum of two ranges: i.e. their aggressive merge. 3966 static IntRange meet(IntRange L, IntRange R) { 3967 return IntRange(std::min(L.Width, R.Width), 3968 L.NonNegative || R.NonNegative); 3969 } 3970}; 3971 3972static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, 3973 unsigned MaxWidth) { 3974 if (value.isSigned() && value.isNegative()) 3975 return IntRange(value.getMinSignedBits(), false); 3976 3977 if (value.getBitWidth() > MaxWidth) 3978 value = value.trunc(MaxWidth); 3979 3980 // isNonNegative() just checks the sign bit without considering 3981 // signedness. 3982 return IntRange(value.getActiveBits(), true); 3983} 3984 3985static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty, 3986 unsigned MaxWidth) { 3987 if (result.isInt()) 3988 return GetValueRange(C, result.getInt(), MaxWidth); 3989 3990 if (result.isVector()) { 3991 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth); 3992 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) { 3993 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth); 3994 R = IntRange::join(R, El); 3995 } 3996 return R; 3997 } 3998 3999 if (result.isComplexInt()) { 4000 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth); 4001 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth); 4002 return IntRange::join(R, I); 4003 } 4004 4005 // This can happen with lossless casts to intptr_t of "based" lvalues. 4006 // Assume it might use arbitrary bits. 4007 // FIXME: The only reason we need to pass the type in here is to get 4008 // the sign right on this one case. It would be nice if APValue 4009 // preserved this. 4010 assert(result.isLValue() || result.isAddrLabelDiff()); 4011 return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType()); 4012} 4013 4014/// Pseudo-evaluate the given integer expression, estimating the 4015/// range of values it might take. 4016/// 4017/// \param MaxWidth - the width to which the value will be truncated 4018static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) { 4019 E = E->IgnoreParens(); 4020 4021 // Try a full evaluation first. 4022 Expr::EvalResult result; 4023 if (E->EvaluateAsRValue(result, C)) 4024 return GetValueRange(C, result.Val, E->getType(), MaxWidth); 4025 4026 // I think we only want to look through implicit casts here; if the 4027 // user has an explicit widening cast, we should treat the value as 4028 // being of the new, wider type. 4029 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) { 4030 if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue) 4031 return GetExprRange(C, CE->getSubExpr(), MaxWidth); 4032 4033 IntRange OutputTypeRange = IntRange::forValueOfType(C, CE->getType()); 4034 4035 bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast); 4036 4037 // Assume that non-integer casts can span the full range of the type. 4038 if (!isIntegerCast) 4039 return OutputTypeRange; 4040 4041 IntRange SubRange 4042 = GetExprRange(C, CE->getSubExpr(), 4043 std::min(MaxWidth, OutputTypeRange.Width)); 4044 4045 // Bail out if the subexpr's range is as wide as the cast type. 4046 if (SubRange.Width >= OutputTypeRange.Width) 4047 return OutputTypeRange; 4048 4049 // Otherwise, we take the smaller width, and we're non-negative if 4050 // either the output type or the subexpr is. 4051 return IntRange(SubRange.Width, 4052 SubRange.NonNegative || OutputTypeRange.NonNegative); 4053 } 4054 4055 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 4056 // If we can fold the condition, just take that operand. 4057 bool CondResult; 4058 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C)) 4059 return GetExprRange(C, CondResult ? CO->getTrueExpr() 4060 : CO->getFalseExpr(), 4061 MaxWidth); 4062 4063 // Otherwise, conservatively merge. 4064 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth); 4065 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth); 4066 return IntRange::join(L, R); 4067 } 4068 4069 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 4070 switch (BO->getOpcode()) { 4071 4072 // Boolean-valued operations are single-bit and positive. 4073 case BO_LAnd: 4074 case BO_LOr: 4075 case BO_LT: 4076 case BO_GT: 4077 case BO_LE: 4078 case BO_GE: 4079 case BO_EQ: 4080 case BO_NE: 4081 return IntRange::forBoolType(); 4082 4083 // The type of the assignments is the type of the LHS, so the RHS 4084 // is not necessarily the same type. 4085 case BO_MulAssign: 4086 case BO_DivAssign: 4087 case BO_RemAssign: 4088 case BO_AddAssign: 4089 case BO_SubAssign: 4090 case BO_XorAssign: 4091 case BO_OrAssign: 4092 // TODO: bitfields? 4093 return IntRange::forValueOfType(C, E->getType()); 4094 4095 // Simple assignments just pass through the RHS, which will have 4096 // been coerced to the LHS type. 4097 case BO_Assign: 4098 // TODO: bitfields? 4099 return GetExprRange(C, BO->getRHS(), MaxWidth); 4100 4101 // Operations with opaque sources are black-listed. 4102 case BO_PtrMemD: 4103 case BO_PtrMemI: 4104 return IntRange::forValueOfType(C, E->getType()); 4105 4106 // Bitwise-and uses the *infinum* of the two source ranges. 4107 case BO_And: 4108 case BO_AndAssign: 4109 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth), 4110 GetExprRange(C, BO->getRHS(), MaxWidth)); 4111 4112 // Left shift gets black-listed based on a judgement call. 4113 case BO_Shl: 4114 // ...except that we want to treat '1 << (blah)' as logically 4115 // positive. It's an important idiom. 4116 if (IntegerLiteral *I 4117 = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) { 4118 if (I->getValue() == 1) { 4119 IntRange R = IntRange::forValueOfType(C, E->getType()); 4120 return IntRange(R.Width, /*NonNegative*/ true); 4121 } 4122 } 4123 // fallthrough 4124 4125 case BO_ShlAssign: 4126 return IntRange::forValueOfType(C, E->getType()); 4127 4128 // Right shift by a constant can narrow its left argument. 4129 case BO_Shr: 4130 case BO_ShrAssign: { 4131 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 4132 4133 // If the shift amount is a positive constant, drop the width by 4134 // that much. 4135 llvm::APSInt shift; 4136 if (BO->getRHS()->isIntegerConstantExpr(shift, C) && 4137 shift.isNonNegative()) { 4138 unsigned zext = shift.getZExtValue(); 4139 if (zext >= L.Width) 4140 L.Width = (L.NonNegative ? 0 : 1); 4141 else 4142 L.Width -= zext; 4143 } 4144 4145 return L; 4146 } 4147 4148 // Comma acts as its right operand. 4149 case BO_Comma: 4150 return GetExprRange(C, BO->getRHS(), MaxWidth); 4151 4152 // Black-list pointer subtractions. 4153 case BO_Sub: 4154 if (BO->getLHS()->getType()->isPointerType()) 4155 return IntRange::forValueOfType(C, E->getType()); 4156 break; 4157 4158 // The width of a division result is mostly determined by the size 4159 // of the LHS. 4160 case BO_Div: { 4161 // Don't 'pre-truncate' the operands. 4162 unsigned opWidth = C.getIntWidth(E->getType()); 4163 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 4164 4165 // If the divisor is constant, use that. 4166 llvm::APSInt divisor; 4167 if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) { 4168 unsigned log2 = divisor.logBase2(); // floor(log_2(divisor)) 4169 if (log2 >= L.Width) 4170 L.Width = (L.NonNegative ? 0 : 1); 4171 else 4172 L.Width = std::min(L.Width - log2, MaxWidth); 4173 return L; 4174 } 4175 4176 // Otherwise, just use the LHS's width. 4177 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 4178 return IntRange(L.Width, L.NonNegative && R.NonNegative); 4179 } 4180 4181 // The result of a remainder can't be larger than the result of 4182 // either side. 4183 case BO_Rem: { 4184 // Don't 'pre-truncate' the operands. 4185 unsigned opWidth = C.getIntWidth(E->getType()); 4186 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 4187 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 4188 4189 IntRange meet = IntRange::meet(L, R); 4190 meet.Width = std::min(meet.Width, MaxWidth); 4191 return meet; 4192 } 4193 4194 // The default behavior is okay for these. 4195 case BO_Mul: 4196 case BO_Add: 4197 case BO_Xor: 4198 case BO_Or: 4199 break; 4200 } 4201 4202 // The default case is to treat the operation as if it were closed 4203 // on the narrowest type that encompasses both operands. 4204 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 4205 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth); 4206 return IntRange::join(L, R); 4207 } 4208 4209 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 4210 switch (UO->getOpcode()) { 4211 // Boolean-valued operations are white-listed. 4212 case UO_LNot: 4213 return IntRange::forBoolType(); 4214 4215 // Operations with opaque sources are black-listed. 4216 case UO_Deref: 4217 case UO_AddrOf: // should be impossible 4218 return IntRange::forValueOfType(C, E->getType()); 4219 4220 default: 4221 return GetExprRange(C, UO->getSubExpr(), MaxWidth); 4222 } 4223 } 4224 4225 if (dyn_cast<OffsetOfExpr>(E)) { 4226 IntRange::forValueOfType(C, E->getType()); 4227 } 4228 4229 if (FieldDecl *BitField = E->getBitField()) 4230 return IntRange(BitField->getBitWidthValue(C), 4231 BitField->getType()->isUnsignedIntegerOrEnumerationType()); 4232 4233 return IntRange::forValueOfType(C, E->getType()); 4234} 4235 4236static IntRange GetExprRange(ASTContext &C, Expr *E) { 4237 return GetExprRange(C, E, C.getIntWidth(E->getType())); 4238} 4239 4240/// Checks whether the given value, which currently has the given 4241/// source semantics, has the same value when coerced through the 4242/// target semantics. 4243static bool IsSameFloatAfterCast(const llvm::APFloat &value, 4244 const llvm::fltSemantics &Src, 4245 const llvm::fltSemantics &Tgt) { 4246 llvm::APFloat truncated = value; 4247 4248 bool ignored; 4249 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored); 4250 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored); 4251 4252 return truncated.bitwiseIsEqual(value); 4253} 4254 4255/// Checks whether the given value, which currently has the given 4256/// source semantics, has the same value when coerced through the 4257/// target semantics. 4258/// 4259/// The value might be a vector of floats (or a complex number). 4260static bool IsSameFloatAfterCast(const APValue &value, 4261 const llvm::fltSemantics &Src, 4262 const llvm::fltSemantics &Tgt) { 4263 if (value.isFloat()) 4264 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt); 4265 4266 if (value.isVector()) { 4267 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i) 4268 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt)) 4269 return false; 4270 return true; 4271 } 4272 4273 assert(value.isComplexFloat()); 4274 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) && 4275 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt)); 4276} 4277 4278static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC); 4279 4280static bool IsZero(Sema &S, Expr *E) { 4281 // Suppress cases where we are comparing against an enum constant. 4282 if (const DeclRefExpr *DR = 4283 dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts())) 4284 if (isa<EnumConstantDecl>(DR->getDecl())) 4285 return false; 4286 4287 // Suppress cases where the '0' value is expanded from a macro. 4288 if (E->getLocStart().isMacroID()) 4289 return false; 4290 4291 llvm::APSInt Value; 4292 return E->isIntegerConstantExpr(Value, S.Context) && Value == 0; 4293} 4294 4295static bool HasEnumType(Expr *E) { 4296 // Strip off implicit integral promotions. 4297 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 4298 if (ICE->getCastKind() != CK_IntegralCast && 4299 ICE->getCastKind() != CK_NoOp) 4300 break; 4301 E = ICE->getSubExpr(); 4302 } 4303 4304 return E->getType()->isEnumeralType(); 4305} 4306 4307static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) { 4308 BinaryOperatorKind op = E->getOpcode(); 4309 if (E->isValueDependent()) 4310 return; 4311 4312 if (op == BO_LT && IsZero(S, E->getRHS())) { 4313 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 4314 << "< 0" << "false" << HasEnumType(E->getLHS()) 4315 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4316 } else if (op == BO_GE && IsZero(S, E->getRHS())) { 4317 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 4318 << ">= 0" << "true" << HasEnumType(E->getLHS()) 4319 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4320 } else if (op == BO_GT && IsZero(S, E->getLHS())) { 4321 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 4322 << "0 >" << "false" << HasEnumType(E->getRHS()) 4323 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4324 } else if (op == BO_LE && IsZero(S, E->getLHS())) { 4325 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 4326 << "0 <=" << "true" << HasEnumType(E->getRHS()) 4327 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4328 } 4329} 4330 4331static void DiagnoseOutOfRangeComparison(Sema &S, BinaryOperator *E, 4332 Expr *Constant, Expr *Other, 4333 llvm::APSInt Value, 4334 bool RhsConstant) { 4335 // 0 values are handled later by CheckTrivialUnsignedComparison(). 4336 if (Value == 0) 4337 return; 4338 4339 BinaryOperatorKind op = E->getOpcode(); 4340 QualType OtherT = Other->getType(); 4341 QualType ConstantT = Constant->getType(); 4342 QualType CommonT = E->getLHS()->getType(); 4343 if (S.Context.hasSameUnqualifiedType(OtherT, ConstantT)) 4344 return; 4345 assert((OtherT->isIntegerType() && ConstantT->isIntegerType()) 4346 && "comparison with non-integer type"); 4347 4348 bool ConstantSigned = ConstantT->isSignedIntegerType(); 4349 bool OtherSigned = OtherT->isSignedIntegerType(); 4350 bool CommonSigned = CommonT->isSignedIntegerType(); 4351 4352 bool EqualityOnly = false; 4353 4354 // TODO: Investigate using GetExprRange() to get tighter bounds on 4355 // on the bit ranges. 4356 IntRange OtherRange = IntRange::forValueOfType(S.Context, OtherT); 4357 unsigned OtherWidth = OtherRange.Width; 4358 4359 if (CommonSigned) { 4360 // The common type is signed, therefore no signed to unsigned conversion. 4361 if (OtherSigned) { 4362 // Check that the constant is representable in type OtherT. 4363 if (ConstantSigned) { 4364 if (OtherWidth >= Value.getMinSignedBits()) 4365 return; 4366 } else { // !ConstantSigned 4367 if (OtherWidth >= Value.getActiveBits() + 1) 4368 return; 4369 } 4370 } else { // !OtherSigned 4371 // Check that the constant is representable in type OtherT. 4372 // Negative values are out of range. 4373 if (ConstantSigned) { 4374 if (Value.isNonNegative() && OtherWidth >= Value.getActiveBits()) 4375 return; 4376 } else { // !ConstantSigned 4377 if (OtherWidth >= Value.getActiveBits()) 4378 return; 4379 } 4380 } 4381 } else { // !CommonSigned 4382 if (!OtherSigned) { 4383 if (OtherWidth >= Value.getActiveBits()) 4384 return; 4385 } else if (OtherSigned && !ConstantSigned) { 4386 // Check to see if the constant is representable in OtherT. 4387 if (OtherWidth > Value.getActiveBits()) 4388 return; 4389 // Check to see if the constant is equivalent to a negative value 4390 // cast to CommonT. 4391 if (S.Context.getIntWidth(ConstantT) == S.Context.getIntWidth(CommonT) && 4392 Value.isNegative() && Value.getMinSignedBits() <= OtherWidth) 4393 return; 4394 // The constant value rests between values that OtherT can represent after 4395 // conversion. Relational comparison still works, but equality 4396 // comparisons will be tautological. 4397 EqualityOnly = true; 4398 } else { // OtherSigned && ConstantSigned 4399 assert(0 && "Two signed types converted to unsigned types."); 4400 } 4401 } 4402 4403 bool PositiveConstant = !ConstantSigned || Value.isNonNegative(); 4404 4405 bool IsTrue = true; 4406 if (op == BO_EQ || op == BO_NE) { 4407 IsTrue = op == BO_NE; 4408 } else if (EqualityOnly) { 4409 return; 4410 } else if (RhsConstant) { 4411 if (op == BO_GT || op == BO_GE) 4412 IsTrue = !PositiveConstant; 4413 else // op == BO_LT || op == BO_LE 4414 IsTrue = PositiveConstant; 4415 } else { 4416 if (op == BO_LT || op == BO_LE) 4417 IsTrue = !PositiveConstant; 4418 else // op == BO_GT || op == BO_GE 4419 IsTrue = PositiveConstant; 4420 } 4421 SmallString<16> PrettySourceValue(Value.toString(10)); 4422 S.Diag(E->getOperatorLoc(), diag::warn_out_of_range_compare) 4423 << PrettySourceValue << OtherT << IsTrue 4424 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4425} 4426 4427/// Analyze the operands of the given comparison. Implements the 4428/// fallback case from AnalyzeComparison. 4429static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) { 4430 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 4431 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 4432} 4433 4434/// \brief Implements -Wsign-compare. 4435/// 4436/// \param E the binary operator to check for warnings 4437static void AnalyzeComparison(Sema &S, BinaryOperator *E) { 4438 // The type the comparison is being performed in. 4439 QualType T = E->getLHS()->getType(); 4440 assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType()) 4441 && "comparison with mismatched types"); 4442 if (E->isValueDependent()) 4443 return AnalyzeImpConvsInComparison(S, E); 4444 4445 Expr *LHS = E->getLHS()->IgnoreParenImpCasts(); 4446 Expr *RHS = E->getRHS()->IgnoreParenImpCasts(); 4447 4448 bool IsComparisonConstant = false; 4449 4450 // Check whether an integer constant comparison results in a value 4451 // of 'true' or 'false'. 4452 if (T->isIntegralType(S.Context)) { 4453 llvm::APSInt RHSValue; 4454 bool IsRHSIntegralLiteral = 4455 RHS->isIntegerConstantExpr(RHSValue, S.Context); 4456 llvm::APSInt LHSValue; 4457 bool IsLHSIntegralLiteral = 4458 LHS->isIntegerConstantExpr(LHSValue, S.Context); 4459 if (IsRHSIntegralLiteral && !IsLHSIntegralLiteral) 4460 DiagnoseOutOfRangeComparison(S, E, RHS, LHS, RHSValue, true); 4461 else if (!IsRHSIntegralLiteral && IsLHSIntegralLiteral) 4462 DiagnoseOutOfRangeComparison(S, E, LHS, RHS, LHSValue, false); 4463 else 4464 IsComparisonConstant = 4465 (IsRHSIntegralLiteral && IsLHSIntegralLiteral); 4466 } else if (!T->hasUnsignedIntegerRepresentation()) 4467 IsComparisonConstant = E->isIntegerConstantExpr(S.Context); 4468 4469 // We don't do anything special if this isn't an unsigned integral 4470 // comparison: we're only interested in integral comparisons, and 4471 // signed comparisons only happen in cases we don't care to warn about. 4472 // 4473 // We also don't care about value-dependent expressions or expressions 4474 // whose result is a constant. 4475 if (!T->hasUnsignedIntegerRepresentation() || IsComparisonConstant) 4476 return AnalyzeImpConvsInComparison(S, E); 4477 4478 // Check to see if one of the (unmodified) operands is of different 4479 // signedness. 4480 Expr *signedOperand, *unsignedOperand; 4481 if (LHS->getType()->hasSignedIntegerRepresentation()) { 4482 assert(!RHS->getType()->hasSignedIntegerRepresentation() && 4483 "unsigned comparison between two signed integer expressions?"); 4484 signedOperand = LHS; 4485 unsignedOperand = RHS; 4486 } else if (RHS->getType()->hasSignedIntegerRepresentation()) { 4487 signedOperand = RHS; 4488 unsignedOperand = LHS; 4489 } else { 4490 CheckTrivialUnsignedComparison(S, E); 4491 return AnalyzeImpConvsInComparison(S, E); 4492 } 4493 4494 // Otherwise, calculate the effective range of the signed operand. 4495 IntRange signedRange = GetExprRange(S.Context, signedOperand); 4496 4497 // Go ahead and analyze implicit conversions in the operands. Note 4498 // that we skip the implicit conversions on both sides. 4499 AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc()); 4500 AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc()); 4501 4502 // If the signed range is non-negative, -Wsign-compare won't fire, 4503 // but we should still check for comparisons which are always true 4504 // or false. 4505 if (signedRange.NonNegative) 4506 return CheckTrivialUnsignedComparison(S, E); 4507 4508 // For (in)equality comparisons, if the unsigned operand is a 4509 // constant which cannot collide with a overflowed signed operand, 4510 // then reinterpreting the signed operand as unsigned will not 4511 // change the result of the comparison. 4512 if (E->isEqualityOp()) { 4513 unsigned comparisonWidth = S.Context.getIntWidth(T); 4514 IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand); 4515 4516 // We should never be unable to prove that the unsigned operand is 4517 // non-negative. 4518 assert(unsignedRange.NonNegative && "unsigned range includes negative?"); 4519 4520 if (unsignedRange.Width < comparisonWidth) 4521 return; 4522 } 4523 4524 S.DiagRuntimeBehavior(E->getOperatorLoc(), E, 4525 S.PDiag(diag::warn_mixed_sign_comparison) 4526 << LHS->getType() << RHS->getType() 4527 << LHS->getSourceRange() << RHS->getSourceRange()); 4528} 4529 4530/// Analyzes an attempt to assign the given value to a bitfield. 4531/// 4532/// Returns true if there was something fishy about the attempt. 4533static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init, 4534 SourceLocation InitLoc) { 4535 assert(Bitfield->isBitField()); 4536 if (Bitfield->isInvalidDecl()) 4537 return false; 4538 4539 // White-list bool bitfields. 4540 if (Bitfield->getType()->isBooleanType()) 4541 return false; 4542 4543 // Ignore value- or type-dependent expressions. 4544 if (Bitfield->getBitWidth()->isValueDependent() || 4545 Bitfield->getBitWidth()->isTypeDependent() || 4546 Init->isValueDependent() || 4547 Init->isTypeDependent()) 4548 return false; 4549 4550 Expr *OriginalInit = Init->IgnoreParenImpCasts(); 4551 4552 llvm::APSInt Value; 4553 if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects)) 4554 return false; 4555 4556 unsigned OriginalWidth = Value.getBitWidth(); 4557 unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context); 4558 4559 if (OriginalWidth <= FieldWidth) 4560 return false; 4561 4562 // Compute the value which the bitfield will contain. 4563 llvm::APSInt TruncatedValue = Value.trunc(FieldWidth); 4564 TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType()); 4565 4566 // Check whether the stored value is equal to the original value. 4567 TruncatedValue = TruncatedValue.extend(OriginalWidth); 4568 if (llvm::APSInt::isSameValue(Value, TruncatedValue)) 4569 return false; 4570 4571 // Special-case bitfields of width 1: booleans are naturally 0/1, and 4572 // therefore don't strictly fit into a signed bitfield of width 1. 4573 if (FieldWidth == 1 && Value == 1) 4574 return false; 4575 4576 std::string PrettyValue = Value.toString(10); 4577 std::string PrettyTrunc = TruncatedValue.toString(10); 4578 4579 S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant) 4580 << PrettyValue << PrettyTrunc << OriginalInit->getType() 4581 << Init->getSourceRange(); 4582 4583 return true; 4584} 4585 4586/// Analyze the given simple or compound assignment for warning-worthy 4587/// operations. 4588static void AnalyzeAssignment(Sema &S, BinaryOperator *E) { 4589 // Just recurse on the LHS. 4590 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 4591 4592 // We want to recurse on the RHS as normal unless we're assigning to 4593 // a bitfield. 4594 if (FieldDecl *Bitfield = E->getLHS()->getBitField()) { 4595 if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(), 4596 E->getOperatorLoc())) { 4597 // Recurse, ignoring any implicit conversions on the RHS. 4598 return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(), 4599 E->getOperatorLoc()); 4600 } 4601 } 4602 4603 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 4604} 4605 4606/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 4607static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T, 4608 SourceLocation CContext, unsigned diag, 4609 bool pruneControlFlow = false) { 4610 if (pruneControlFlow) { 4611 S.DiagRuntimeBehavior(E->getExprLoc(), E, 4612 S.PDiag(diag) 4613 << SourceType << T << E->getSourceRange() 4614 << SourceRange(CContext)); 4615 return; 4616 } 4617 S.Diag(E->getExprLoc(), diag) 4618 << SourceType << T << E->getSourceRange() << SourceRange(CContext); 4619} 4620 4621/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 4622static void DiagnoseImpCast(Sema &S, Expr *E, QualType T, 4623 SourceLocation CContext, unsigned diag, 4624 bool pruneControlFlow = false) { 4625 DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow); 4626} 4627 4628/// Diagnose an implicit cast from a literal expression. Does not warn when the 4629/// cast wouldn't lose information. 4630void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T, 4631 SourceLocation CContext) { 4632 // Try to convert the literal exactly to an integer. If we can, don't warn. 4633 bool isExact = false; 4634 const llvm::APFloat &Value = FL->getValue(); 4635 llvm::APSInt IntegerValue(S.Context.getIntWidth(T), 4636 T->hasUnsignedIntegerRepresentation()); 4637 if (Value.convertToInteger(IntegerValue, 4638 llvm::APFloat::rmTowardZero, &isExact) 4639 == llvm::APFloat::opOK && isExact) 4640 return; 4641 4642 SmallString<16> PrettySourceValue; 4643 Value.toString(PrettySourceValue); 4644 SmallString<16> PrettyTargetValue; 4645 if (T->isSpecificBuiltinType(BuiltinType::Bool)) 4646 PrettyTargetValue = IntegerValue == 0 ? "false" : "true"; 4647 else 4648 IntegerValue.toString(PrettyTargetValue); 4649 4650 S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer) 4651 << FL->getType() << T.getUnqualifiedType() << PrettySourceValue 4652 << PrettyTargetValue << FL->getSourceRange() << SourceRange(CContext); 4653} 4654 4655std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) { 4656 if (!Range.Width) return "0"; 4657 4658 llvm::APSInt ValueInRange = Value; 4659 ValueInRange.setIsSigned(!Range.NonNegative); 4660 ValueInRange = ValueInRange.trunc(Range.Width); 4661 return ValueInRange.toString(10); 4662} 4663 4664static bool IsImplicitBoolFloatConversion(Sema &S, Expr *Ex, bool ToBool) { 4665 if (!isa<ImplicitCastExpr>(Ex)) 4666 return false; 4667 4668 Expr *InnerE = Ex->IgnoreParenImpCasts(); 4669 const Type *Target = S.Context.getCanonicalType(Ex->getType()).getTypePtr(); 4670 const Type *Source = 4671 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 4672 if (Target->isDependentType()) 4673 return false; 4674 4675 const BuiltinType *FloatCandidateBT = 4676 dyn_cast<BuiltinType>(ToBool ? Source : Target); 4677 const Type *BoolCandidateType = ToBool ? Target : Source; 4678 4679 return (BoolCandidateType->isSpecificBuiltinType(BuiltinType::Bool) && 4680 FloatCandidateBT && (FloatCandidateBT->isFloatingPoint())); 4681} 4682 4683void CheckImplicitArgumentConversions(Sema &S, CallExpr *TheCall, 4684 SourceLocation CC) { 4685 unsigned NumArgs = TheCall->getNumArgs(); 4686 for (unsigned i = 0; i < NumArgs; ++i) { 4687 Expr *CurrA = TheCall->getArg(i); 4688 if (!IsImplicitBoolFloatConversion(S, CurrA, true)) 4689 continue; 4690 4691 bool IsSwapped = ((i > 0) && 4692 IsImplicitBoolFloatConversion(S, TheCall->getArg(i - 1), false)); 4693 IsSwapped |= ((i < (NumArgs - 1)) && 4694 IsImplicitBoolFloatConversion(S, TheCall->getArg(i + 1), false)); 4695 if (IsSwapped) { 4696 // Warn on this floating-point to bool conversion. 4697 DiagnoseImpCast(S, CurrA->IgnoreParenImpCasts(), 4698 CurrA->getType(), CC, 4699 diag::warn_impcast_floating_point_to_bool); 4700 } 4701 } 4702} 4703 4704void CheckImplicitConversion(Sema &S, Expr *E, QualType T, 4705 SourceLocation CC, bool *ICContext = 0) { 4706 if (E->isTypeDependent() || E->isValueDependent()) return; 4707 4708 const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr(); 4709 const Type *Target = S.Context.getCanonicalType(T).getTypePtr(); 4710 if (Source == Target) return; 4711 if (Target->isDependentType()) return; 4712 4713 // If the conversion context location is invalid don't complain. We also 4714 // don't want to emit a warning if the issue occurs from the expansion of 4715 // a system macro. The problem is that 'getSpellingLoc()' is slow, so we 4716 // delay this check as long as possible. Once we detect we are in that 4717 // scenario, we just return. 4718 if (CC.isInvalid()) 4719 return; 4720 4721 // Diagnose implicit casts to bool. 4722 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) { 4723 if (isa<StringLiteral>(E)) 4724 // Warn on string literal to bool. Checks for string literals in logical 4725 // expressions, for instances, assert(0 && "error here"), is prevented 4726 // by a check in AnalyzeImplicitConversions(). 4727 return DiagnoseImpCast(S, E, T, CC, 4728 diag::warn_impcast_string_literal_to_bool); 4729 if (Source->isFunctionType()) { 4730 // Warn on function to bool. Checks free functions and static member 4731 // functions. Weakly imported functions are excluded from the check, 4732 // since it's common to test their value to check whether the linker 4733 // found a definition for them. 4734 ValueDecl *D = 0; 4735 if (DeclRefExpr* R = dyn_cast<DeclRefExpr>(E)) { 4736 D = R->getDecl(); 4737 } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) { 4738 D = M->getMemberDecl(); 4739 } 4740 4741 if (D && !D->isWeak()) { 4742 if (FunctionDecl* F = dyn_cast<FunctionDecl>(D)) { 4743 S.Diag(E->getExprLoc(), diag::warn_impcast_function_to_bool) 4744 << F << E->getSourceRange() << SourceRange(CC); 4745 S.Diag(E->getExprLoc(), diag::note_function_to_bool_silence) 4746 << FixItHint::CreateInsertion(E->getExprLoc(), "&"); 4747 QualType ReturnType; 4748 UnresolvedSet<4> NonTemplateOverloads; 4749 S.isExprCallable(*E, ReturnType, NonTemplateOverloads); 4750 if (!ReturnType.isNull() 4751 && ReturnType->isSpecificBuiltinType(BuiltinType::Bool)) 4752 S.Diag(E->getExprLoc(), diag::note_function_to_bool_call) 4753 << FixItHint::CreateInsertion( 4754 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()), "()"); 4755 return; 4756 } 4757 } 4758 } 4759 } 4760 4761 // Strip vector types. 4762 if (isa<VectorType>(Source)) { 4763 if (!isa<VectorType>(Target)) { 4764 if (S.SourceMgr.isInSystemMacro(CC)) 4765 return; 4766 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar); 4767 } 4768 4769 // If the vector cast is cast between two vectors of the same size, it is 4770 // a bitcast, not a conversion. 4771 if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target)) 4772 return; 4773 4774 Source = cast<VectorType>(Source)->getElementType().getTypePtr(); 4775 Target = cast<VectorType>(Target)->getElementType().getTypePtr(); 4776 } 4777 4778 // Strip complex types. 4779 if (isa<ComplexType>(Source)) { 4780 if (!isa<ComplexType>(Target)) { 4781 if (S.SourceMgr.isInSystemMacro(CC)) 4782 return; 4783 4784 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar); 4785 } 4786 4787 Source = cast<ComplexType>(Source)->getElementType().getTypePtr(); 4788 Target = cast<ComplexType>(Target)->getElementType().getTypePtr(); 4789 } 4790 4791 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source); 4792 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target); 4793 4794 // If the source is floating point... 4795 if (SourceBT && SourceBT->isFloatingPoint()) { 4796 // ...and the target is floating point... 4797 if (TargetBT && TargetBT->isFloatingPoint()) { 4798 // ...then warn if we're dropping FP rank. 4799 4800 // Builtin FP kinds are ordered by increasing FP rank. 4801 if (SourceBT->getKind() > TargetBT->getKind()) { 4802 // Don't warn about float constants that are precisely 4803 // representable in the target type. 4804 Expr::EvalResult result; 4805 if (E->EvaluateAsRValue(result, S.Context)) { 4806 // Value might be a float, a float vector, or a float complex. 4807 if (IsSameFloatAfterCast(result.Val, 4808 S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)), 4809 S.Context.getFloatTypeSemantics(QualType(SourceBT, 0)))) 4810 return; 4811 } 4812 4813 if (S.SourceMgr.isInSystemMacro(CC)) 4814 return; 4815 4816 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision); 4817 } 4818 return; 4819 } 4820 4821 // If the target is integral, always warn. 4822 if (TargetBT && TargetBT->isInteger()) { 4823 if (S.SourceMgr.isInSystemMacro(CC)) 4824 return; 4825 4826 Expr *InnerE = E->IgnoreParenImpCasts(); 4827 // We also want to warn on, e.g., "int i = -1.234" 4828 if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE)) 4829 if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus) 4830 InnerE = UOp->getSubExpr()->IgnoreParenImpCasts(); 4831 4832 if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) { 4833 DiagnoseFloatingLiteralImpCast(S, FL, T, CC); 4834 } else { 4835 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer); 4836 } 4837 } 4838 4839 // If the target is bool, warn if expr is a function or method call. 4840 if (Target->isSpecificBuiltinType(BuiltinType::Bool) && 4841 isa<CallExpr>(E)) { 4842 // Check last argument of function call to see if it is an 4843 // implicit cast from a type matching the type the result 4844 // is being cast to. 4845 CallExpr *CEx = cast<CallExpr>(E); 4846 unsigned NumArgs = CEx->getNumArgs(); 4847 if (NumArgs > 0) { 4848 Expr *LastA = CEx->getArg(NumArgs - 1); 4849 Expr *InnerE = LastA->IgnoreParenImpCasts(); 4850 const Type *InnerType = 4851 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 4852 if (isa<ImplicitCastExpr>(LastA) && (InnerType == Target)) { 4853 // Warn on this floating-point to bool conversion 4854 DiagnoseImpCast(S, E, T, CC, 4855 diag::warn_impcast_floating_point_to_bool); 4856 } 4857 } 4858 } 4859 return; 4860 } 4861 4862 if ((E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull) 4863 == Expr::NPCK_GNUNull) && !Target->isAnyPointerType() 4864 && !Target->isBlockPointerType() && !Target->isMemberPointerType() 4865 && Target->isScalarType()) { 4866 SourceLocation Loc = E->getSourceRange().getBegin(); 4867 if (Loc.isMacroID()) 4868 Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first; 4869 if (!Loc.isMacroID() || CC.isMacroID()) 4870 S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer) 4871 << T << clang::SourceRange(CC) 4872 << FixItHint::CreateReplacement(Loc, S.getFixItZeroLiteralForType(T)); 4873 } 4874 4875 if (!Source->isIntegerType() || !Target->isIntegerType()) 4876 return; 4877 4878 // TODO: remove this early return once the false positives for constant->bool 4879 // in templates, macros, etc, are reduced or removed. 4880 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) 4881 return; 4882 4883 IntRange SourceRange = GetExprRange(S.Context, E); 4884 IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target); 4885 4886 if (SourceRange.Width > TargetRange.Width) { 4887 // If the source is a constant, use a default-on diagnostic. 4888 // TODO: this should happen for bitfield stores, too. 4889 llvm::APSInt Value(32); 4890 if (E->isIntegerConstantExpr(Value, S.Context)) { 4891 if (S.SourceMgr.isInSystemMacro(CC)) 4892 return; 4893 4894 std::string PrettySourceValue = Value.toString(10); 4895 std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange); 4896 4897 S.DiagRuntimeBehavior(E->getExprLoc(), E, 4898 S.PDiag(diag::warn_impcast_integer_precision_constant) 4899 << PrettySourceValue << PrettyTargetValue 4900 << E->getType() << T << E->getSourceRange() 4901 << clang::SourceRange(CC)); 4902 return; 4903 } 4904 4905 // People want to build with -Wshorten-64-to-32 and not -Wconversion. 4906 if (S.SourceMgr.isInSystemMacro(CC)) 4907 return; 4908 4909 if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64) 4910 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32, 4911 /* pruneControlFlow */ true); 4912 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision); 4913 } 4914 4915 if ((TargetRange.NonNegative && !SourceRange.NonNegative) || 4916 (!TargetRange.NonNegative && SourceRange.NonNegative && 4917 SourceRange.Width == TargetRange.Width)) { 4918 4919 if (S.SourceMgr.isInSystemMacro(CC)) 4920 return; 4921 4922 unsigned DiagID = diag::warn_impcast_integer_sign; 4923 4924 // Traditionally, gcc has warned about this under -Wsign-compare. 4925 // We also want to warn about it in -Wconversion. 4926 // So if -Wconversion is off, use a completely identical diagnostic 4927 // in the sign-compare group. 4928 // The conditional-checking code will 4929 if (ICContext) { 4930 DiagID = diag::warn_impcast_integer_sign_conditional; 4931 *ICContext = true; 4932 } 4933 4934 return DiagnoseImpCast(S, E, T, CC, DiagID); 4935 } 4936 4937 // Diagnose conversions between different enumeration types. 4938 // In C, we pretend that the type of an EnumConstantDecl is its enumeration 4939 // type, to give us better diagnostics. 4940 QualType SourceType = E->getType(); 4941 if (!S.getLangOpts().CPlusPlus) { 4942 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 4943 if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) { 4944 EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext()); 4945 SourceType = S.Context.getTypeDeclType(Enum); 4946 Source = S.Context.getCanonicalType(SourceType).getTypePtr(); 4947 } 4948 } 4949 4950 if (const EnumType *SourceEnum = Source->getAs<EnumType>()) 4951 if (const EnumType *TargetEnum = Target->getAs<EnumType>()) 4952 if ((SourceEnum->getDecl()->getIdentifier() || 4953 SourceEnum->getDecl()->getTypedefNameForAnonDecl()) && 4954 (TargetEnum->getDecl()->getIdentifier() || 4955 TargetEnum->getDecl()->getTypedefNameForAnonDecl()) && 4956 SourceEnum != TargetEnum) { 4957 if (S.SourceMgr.isInSystemMacro(CC)) 4958 return; 4959 4960 return DiagnoseImpCast(S, E, SourceType, T, CC, 4961 diag::warn_impcast_different_enum_types); 4962 } 4963 4964 return; 4965} 4966 4967void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 4968 SourceLocation CC, QualType T); 4969 4970void CheckConditionalOperand(Sema &S, Expr *E, QualType T, 4971 SourceLocation CC, bool &ICContext) { 4972 E = E->IgnoreParenImpCasts(); 4973 4974 if (isa<ConditionalOperator>(E)) 4975 return CheckConditionalOperator(S, cast<ConditionalOperator>(E), CC, T); 4976 4977 AnalyzeImplicitConversions(S, E, CC); 4978 if (E->getType() != T) 4979 return CheckImplicitConversion(S, E, T, CC, &ICContext); 4980 return; 4981} 4982 4983void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 4984 SourceLocation CC, QualType T) { 4985 AnalyzeImplicitConversions(S, E->getCond(), CC); 4986 4987 bool Suspicious = false; 4988 CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious); 4989 CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious); 4990 4991 // If -Wconversion would have warned about either of the candidates 4992 // for a signedness conversion to the context type... 4993 if (!Suspicious) return; 4994 4995 // ...but it's currently ignored... 4996 if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional, 4997 CC)) 4998 return; 4999 5000 // ...then check whether it would have warned about either of the 5001 // candidates for a signedness conversion to the condition type. 5002 if (E->getType() == T) return; 5003 5004 Suspicious = false; 5005 CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(), 5006 E->getType(), CC, &Suspicious); 5007 if (!Suspicious) 5008 CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(), 5009 E->getType(), CC, &Suspicious); 5010} 5011 5012/// AnalyzeImplicitConversions - Find and report any interesting 5013/// implicit conversions in the given expression. There are a couple 5014/// of competing diagnostics here, -Wconversion and -Wsign-compare. 5015void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) { 5016 QualType T = OrigE->getType(); 5017 Expr *E = OrigE->IgnoreParenImpCasts(); 5018 5019 if (E->isTypeDependent() || E->isValueDependent()) 5020 return; 5021 5022 // For conditional operators, we analyze the arguments as if they 5023 // were being fed directly into the output. 5024 if (isa<ConditionalOperator>(E)) { 5025 ConditionalOperator *CO = cast<ConditionalOperator>(E); 5026 CheckConditionalOperator(S, CO, CC, T); 5027 return; 5028 } 5029 5030 // Check implicit argument conversions for function calls. 5031 if (CallExpr *Call = dyn_cast<CallExpr>(E)) 5032 CheckImplicitArgumentConversions(S, Call, CC); 5033 5034 // Go ahead and check any implicit conversions we might have skipped. 5035 // The non-canonical typecheck is just an optimization; 5036 // CheckImplicitConversion will filter out dead implicit conversions. 5037 if (E->getType() != T) 5038 CheckImplicitConversion(S, E, T, CC); 5039 5040 // Now continue drilling into this expression. 5041 5042 // Skip past explicit casts. 5043 if (isa<ExplicitCastExpr>(E)) { 5044 E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts(); 5045 return AnalyzeImplicitConversions(S, E, CC); 5046 } 5047 5048 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 5049 // Do a somewhat different check with comparison operators. 5050 if (BO->isComparisonOp()) 5051 return AnalyzeComparison(S, BO); 5052 5053 // And with simple assignments. 5054 if (BO->getOpcode() == BO_Assign) 5055 return AnalyzeAssignment(S, BO); 5056 } 5057 5058 // These break the otherwise-useful invariant below. Fortunately, 5059 // we don't really need to recurse into them, because any internal 5060 // expressions should have been analyzed already when they were 5061 // built into statements. 5062 if (isa<StmtExpr>(E)) return; 5063 5064 // Don't descend into unevaluated contexts. 5065 if (isa<UnaryExprOrTypeTraitExpr>(E)) return; 5066 5067 // Now just recurse over the expression's children. 5068 CC = E->getExprLoc(); 5069 BinaryOperator *BO = dyn_cast<BinaryOperator>(E); 5070 bool IsLogicalOperator = BO && BO->isLogicalOp(); 5071 for (Stmt::child_range I = E->children(); I; ++I) { 5072 Expr *ChildExpr = dyn_cast_or_null<Expr>(*I); 5073 if (!ChildExpr) 5074 continue; 5075 5076 if (IsLogicalOperator && 5077 isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts())) 5078 // Ignore checking string literals that are in logical operators. 5079 continue; 5080 AnalyzeImplicitConversions(S, ChildExpr, CC); 5081 } 5082} 5083 5084} // end anonymous namespace 5085 5086/// Diagnoses "dangerous" implicit conversions within the given 5087/// expression (which is a full expression). Implements -Wconversion 5088/// and -Wsign-compare. 5089/// 5090/// \param CC the "context" location of the implicit conversion, i.e. 5091/// the most location of the syntactic entity requiring the implicit 5092/// conversion 5093void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) { 5094 // Don't diagnose in unevaluated contexts. 5095 if (isUnevaluatedContext()) 5096 return; 5097 5098 // Don't diagnose for value- or type-dependent expressions. 5099 if (E->isTypeDependent() || E->isValueDependent()) 5100 return; 5101 5102 // Check for array bounds violations in cases where the check isn't triggered 5103 // elsewhere for other Expr types (like BinaryOperators), e.g. when an 5104 // ArraySubscriptExpr is on the RHS of a variable initialization. 5105 CheckArrayAccess(E); 5106 5107 // This is not the right CC for (e.g.) a variable initialization. 5108 AnalyzeImplicitConversions(*this, E, CC); 5109} 5110 5111void Sema::CheckBitFieldInitialization(SourceLocation InitLoc, 5112 FieldDecl *BitField, 5113 Expr *Init) { 5114 (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc); 5115} 5116 5117/// CheckParmsForFunctionDef - Check that the parameters of the given 5118/// function are appropriate for the definition of a function. This 5119/// takes care of any checks that cannot be performed on the 5120/// declaration itself, e.g., that the types of each of the function 5121/// parameters are complete. 5122bool Sema::CheckParmsForFunctionDef(ParmVarDecl **P, ParmVarDecl **PEnd, 5123 bool CheckParameterNames) { 5124 bool HasInvalidParm = false; 5125 for (; P != PEnd; ++P) { 5126 ParmVarDecl *Param = *P; 5127 5128 // C99 6.7.5.3p4: the parameters in a parameter type list in a 5129 // function declarator that is part of a function definition of 5130 // that function shall not have incomplete type. 5131 // 5132 // This is also C++ [dcl.fct]p6. 5133 if (!Param->isInvalidDecl() && 5134 RequireCompleteType(Param->getLocation(), Param->getType(), 5135 diag::err_typecheck_decl_incomplete_type)) { 5136 Param->setInvalidDecl(); 5137 HasInvalidParm = true; 5138 } 5139 5140 // C99 6.9.1p5: If the declarator includes a parameter type list, the 5141 // declaration of each parameter shall include an identifier. 5142 if (CheckParameterNames && 5143 Param->getIdentifier() == 0 && 5144 !Param->isImplicit() && 5145 !getLangOpts().CPlusPlus) 5146 Diag(Param->getLocation(), diag::err_parameter_name_omitted); 5147 5148 // C99 6.7.5.3p12: 5149 // If the function declarator is not part of a definition of that 5150 // function, parameters may have incomplete type and may use the [*] 5151 // notation in their sequences of declarator specifiers to specify 5152 // variable length array types. 5153 QualType PType = Param->getOriginalType(); 5154 if (const ArrayType *AT = Context.getAsArrayType(PType)) { 5155 if (AT->getSizeModifier() == ArrayType::Star) { 5156 // FIXME: This diagnosic should point the '[*]' if source-location 5157 // information is added for it. 5158 Diag(Param->getLocation(), diag::err_array_star_in_function_definition); 5159 } 5160 } 5161 } 5162 5163 return HasInvalidParm; 5164} 5165 5166/// CheckCastAlign - Implements -Wcast-align, which warns when a 5167/// pointer cast increases the alignment requirements. 5168void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) { 5169 // This is actually a lot of work to potentially be doing on every 5170 // cast; don't do it if we're ignoring -Wcast_align (as is the default). 5171 if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align, 5172 TRange.getBegin()) 5173 == DiagnosticsEngine::Ignored) 5174 return; 5175 5176 // Ignore dependent types. 5177 if (T->isDependentType() || Op->getType()->isDependentType()) 5178 return; 5179 5180 // Require that the destination be a pointer type. 5181 const PointerType *DestPtr = T->getAs<PointerType>(); 5182 if (!DestPtr) return; 5183 5184 // If the destination has alignment 1, we're done. 5185 QualType DestPointee = DestPtr->getPointeeType(); 5186 if (DestPointee->isIncompleteType()) return; 5187 CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee); 5188 if (DestAlign.isOne()) return; 5189 5190 // Require that the source be a pointer type. 5191 const PointerType *SrcPtr = Op->getType()->getAs<PointerType>(); 5192 if (!SrcPtr) return; 5193 QualType SrcPointee = SrcPtr->getPointeeType(); 5194 5195 // Whitelist casts from cv void*. We already implicitly 5196 // whitelisted casts to cv void*, since they have alignment 1. 5197 // Also whitelist casts involving incomplete types, which implicitly 5198 // includes 'void'. 5199 if (SrcPointee->isIncompleteType()) return; 5200 5201 CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee); 5202 if (SrcAlign >= DestAlign) return; 5203 5204 Diag(TRange.getBegin(), diag::warn_cast_align) 5205 << Op->getType() << T 5206 << static_cast<unsigned>(SrcAlign.getQuantity()) 5207 << static_cast<unsigned>(DestAlign.getQuantity()) 5208 << TRange << Op->getSourceRange(); 5209} 5210 5211static const Type* getElementType(const Expr *BaseExpr) { 5212 const Type* EltType = BaseExpr->getType().getTypePtr(); 5213 if (EltType->isAnyPointerType()) 5214 return EltType->getPointeeType().getTypePtr(); 5215 else if (EltType->isArrayType()) 5216 return EltType->getBaseElementTypeUnsafe(); 5217 return EltType; 5218} 5219 5220/// \brief Check whether this array fits the idiom of a size-one tail padded 5221/// array member of a struct. 5222/// 5223/// We avoid emitting out-of-bounds access warnings for such arrays as they are 5224/// commonly used to emulate flexible arrays in C89 code. 5225static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size, 5226 const NamedDecl *ND) { 5227 if (Size != 1 || !ND) return false; 5228 5229 const FieldDecl *FD = dyn_cast<FieldDecl>(ND); 5230 if (!FD) return false; 5231 5232 // Don't consider sizes resulting from macro expansions or template argument 5233 // substitution to form C89 tail-padded arrays. 5234 5235 TypeSourceInfo *TInfo = FD->getTypeSourceInfo(); 5236 while (TInfo) { 5237 TypeLoc TL = TInfo->getTypeLoc(); 5238 // Look through typedefs. 5239 const TypedefTypeLoc *TTL = dyn_cast<TypedefTypeLoc>(&TL); 5240 if (TTL) { 5241 const TypedefNameDecl *TDL = TTL->getTypedefNameDecl(); 5242 TInfo = TDL->getTypeSourceInfo(); 5243 continue; 5244 } 5245 ConstantArrayTypeLoc CTL = cast<ConstantArrayTypeLoc>(TL); 5246 const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr()); 5247 if (!SizeExpr || SizeExpr->getExprLoc().isMacroID()) 5248 return false; 5249 break; 5250 } 5251 5252 const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext()); 5253 if (!RD) return false; 5254 if (RD->isUnion()) return false; 5255 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) { 5256 if (!CRD->isStandardLayout()) return false; 5257 } 5258 5259 // See if this is the last field decl in the record. 5260 const Decl *D = FD; 5261 while ((D = D->getNextDeclInContext())) 5262 if (isa<FieldDecl>(D)) 5263 return false; 5264 return true; 5265} 5266 5267void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr, 5268 const ArraySubscriptExpr *ASE, 5269 bool AllowOnePastEnd, bool IndexNegated) { 5270 IndexExpr = IndexExpr->IgnoreParenImpCasts(); 5271 if (IndexExpr->isValueDependent()) 5272 return; 5273 5274 const Type *EffectiveType = getElementType(BaseExpr); 5275 BaseExpr = BaseExpr->IgnoreParenCasts(); 5276 const ConstantArrayType *ArrayTy = 5277 Context.getAsConstantArrayType(BaseExpr->getType()); 5278 if (!ArrayTy) 5279 return; 5280 5281 llvm::APSInt index; 5282 if (!IndexExpr->EvaluateAsInt(index, Context)) 5283 return; 5284 if (IndexNegated) 5285 index = -index; 5286 5287 const NamedDecl *ND = NULL; 5288 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 5289 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 5290 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 5291 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 5292 5293 if (index.isUnsigned() || !index.isNegative()) { 5294 llvm::APInt size = ArrayTy->getSize(); 5295 if (!size.isStrictlyPositive()) 5296 return; 5297 5298 const Type* BaseType = getElementType(BaseExpr); 5299 if (BaseType != EffectiveType) { 5300 // Make sure we're comparing apples to apples when comparing index to size 5301 uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType); 5302 uint64_t array_typesize = Context.getTypeSize(BaseType); 5303 // Handle ptrarith_typesize being zero, such as when casting to void* 5304 if (!ptrarith_typesize) ptrarith_typesize = 1; 5305 if (ptrarith_typesize != array_typesize) { 5306 // There's a cast to a different size type involved 5307 uint64_t ratio = array_typesize / ptrarith_typesize; 5308 // TODO: Be smarter about handling cases where array_typesize is not a 5309 // multiple of ptrarith_typesize 5310 if (ptrarith_typesize * ratio == array_typesize) 5311 size *= llvm::APInt(size.getBitWidth(), ratio); 5312 } 5313 } 5314 5315 if (size.getBitWidth() > index.getBitWidth()) 5316 index = index.zext(size.getBitWidth()); 5317 else if (size.getBitWidth() < index.getBitWidth()) 5318 size = size.zext(index.getBitWidth()); 5319 5320 // For array subscripting the index must be less than size, but for pointer 5321 // arithmetic also allow the index (offset) to be equal to size since 5322 // computing the next address after the end of the array is legal and 5323 // commonly done e.g. in C++ iterators and range-based for loops. 5324 if (AllowOnePastEnd ? index.ule(size) : index.ult(size)) 5325 return; 5326 5327 // Also don't warn for arrays of size 1 which are members of some 5328 // structure. These are often used to approximate flexible arrays in C89 5329 // code. 5330 if (IsTailPaddedMemberArray(*this, size, ND)) 5331 return; 5332 5333 // Suppress the warning if the subscript expression (as identified by the 5334 // ']' location) and the index expression are both from macro expansions 5335 // within a system header. 5336 if (ASE) { 5337 SourceLocation RBracketLoc = SourceMgr.getSpellingLoc( 5338 ASE->getRBracketLoc()); 5339 if (SourceMgr.isInSystemHeader(RBracketLoc)) { 5340 SourceLocation IndexLoc = SourceMgr.getSpellingLoc( 5341 IndexExpr->getLocStart()); 5342 if (SourceMgr.isFromSameFile(RBracketLoc, IndexLoc)) 5343 return; 5344 } 5345 } 5346 5347 unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds; 5348 if (ASE) 5349 DiagID = diag::warn_array_index_exceeds_bounds; 5350 5351 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 5352 PDiag(DiagID) << index.toString(10, true) 5353 << size.toString(10, true) 5354 << (unsigned)size.getLimitedValue(~0U) 5355 << IndexExpr->getSourceRange()); 5356 } else { 5357 unsigned DiagID = diag::warn_array_index_precedes_bounds; 5358 if (!ASE) { 5359 DiagID = diag::warn_ptr_arith_precedes_bounds; 5360 if (index.isNegative()) index = -index; 5361 } 5362 5363 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 5364 PDiag(DiagID) << index.toString(10, true) 5365 << IndexExpr->getSourceRange()); 5366 } 5367 5368 if (!ND) { 5369 // Try harder to find a NamedDecl to point at in the note. 5370 while (const ArraySubscriptExpr *ASE = 5371 dyn_cast<ArraySubscriptExpr>(BaseExpr)) 5372 BaseExpr = ASE->getBase()->IgnoreParenCasts(); 5373 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 5374 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 5375 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 5376 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 5377 } 5378 5379 if (ND) 5380 DiagRuntimeBehavior(ND->getLocStart(), BaseExpr, 5381 PDiag(diag::note_array_index_out_of_bounds) 5382 << ND->getDeclName()); 5383} 5384 5385void Sema::CheckArrayAccess(const Expr *expr) { 5386 int AllowOnePastEnd = 0; 5387 while (expr) { 5388 expr = expr->IgnoreParenImpCasts(); 5389 switch (expr->getStmtClass()) { 5390 case Stmt::ArraySubscriptExprClass: { 5391 const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr); 5392 CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE, 5393 AllowOnePastEnd > 0); 5394 return; 5395 } 5396 case Stmt::UnaryOperatorClass: { 5397 // Only unwrap the * and & unary operators 5398 const UnaryOperator *UO = cast<UnaryOperator>(expr); 5399 expr = UO->getSubExpr(); 5400 switch (UO->getOpcode()) { 5401 case UO_AddrOf: 5402 AllowOnePastEnd++; 5403 break; 5404 case UO_Deref: 5405 AllowOnePastEnd--; 5406 break; 5407 default: 5408 return; 5409 } 5410 break; 5411 } 5412 case Stmt::ConditionalOperatorClass: { 5413 const ConditionalOperator *cond = cast<ConditionalOperator>(expr); 5414 if (const Expr *lhs = cond->getLHS()) 5415 CheckArrayAccess(lhs); 5416 if (const Expr *rhs = cond->getRHS()) 5417 CheckArrayAccess(rhs); 5418 return; 5419 } 5420 default: 5421 return; 5422 } 5423 } 5424} 5425 5426//===--- CHECK: Objective-C retain cycles ----------------------------------// 5427 5428namespace { 5429 struct RetainCycleOwner { 5430 RetainCycleOwner() : Variable(0), Indirect(false) {} 5431 VarDecl *Variable; 5432 SourceRange Range; 5433 SourceLocation Loc; 5434 bool Indirect; 5435 5436 void setLocsFrom(Expr *e) { 5437 Loc = e->getExprLoc(); 5438 Range = e->getSourceRange(); 5439 } 5440 }; 5441} 5442 5443/// Consider whether capturing the given variable can possibly lead to 5444/// a retain cycle. 5445static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) { 5446 // In ARC, it's captured strongly iff the variable has __strong 5447 // lifetime. In MRR, it's captured strongly if the variable is 5448 // __block and has an appropriate type. 5449 if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 5450 return false; 5451 5452 owner.Variable = var; 5453 if (ref) 5454 owner.setLocsFrom(ref); 5455 return true; 5456} 5457 5458static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) { 5459 while (true) { 5460 e = e->IgnoreParens(); 5461 if (CastExpr *cast = dyn_cast<CastExpr>(e)) { 5462 switch (cast->getCastKind()) { 5463 case CK_BitCast: 5464 case CK_LValueBitCast: 5465 case CK_LValueToRValue: 5466 case CK_ARCReclaimReturnedObject: 5467 e = cast->getSubExpr(); 5468 continue; 5469 5470 default: 5471 return false; 5472 } 5473 } 5474 5475 if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) { 5476 ObjCIvarDecl *ivar = ref->getDecl(); 5477 if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 5478 return false; 5479 5480 // Try to find a retain cycle in the base. 5481 if (!findRetainCycleOwner(S, ref->getBase(), owner)) 5482 return false; 5483 5484 if (ref->isFreeIvar()) owner.setLocsFrom(ref); 5485 owner.Indirect = true; 5486 return true; 5487 } 5488 5489 if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) { 5490 VarDecl *var = dyn_cast<VarDecl>(ref->getDecl()); 5491 if (!var) return false; 5492 return considerVariable(var, ref, owner); 5493 } 5494 5495 if (MemberExpr *member = dyn_cast<MemberExpr>(e)) { 5496 if (member->isArrow()) return false; 5497 5498 // Don't count this as an indirect ownership. 5499 e = member->getBase(); 5500 continue; 5501 } 5502 5503 if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) { 5504 // Only pay attention to pseudo-objects on property references. 5505 ObjCPropertyRefExpr *pre 5506 = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm() 5507 ->IgnoreParens()); 5508 if (!pre) return false; 5509 if (pre->isImplicitProperty()) return false; 5510 ObjCPropertyDecl *property = pre->getExplicitProperty(); 5511 if (!property->isRetaining() && 5512 !(property->getPropertyIvarDecl() && 5513 property->getPropertyIvarDecl()->getType() 5514 .getObjCLifetime() == Qualifiers::OCL_Strong)) 5515 return false; 5516 5517 owner.Indirect = true; 5518 if (pre->isSuperReceiver()) { 5519 owner.Variable = S.getCurMethodDecl()->getSelfDecl(); 5520 if (!owner.Variable) 5521 return false; 5522 owner.Loc = pre->getLocation(); 5523 owner.Range = pre->getSourceRange(); 5524 return true; 5525 } 5526 e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase()) 5527 ->getSourceExpr()); 5528 continue; 5529 } 5530 5531 // Array ivars? 5532 5533 return false; 5534 } 5535} 5536 5537namespace { 5538 struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> { 5539 FindCaptureVisitor(ASTContext &Context, VarDecl *variable) 5540 : EvaluatedExprVisitor<FindCaptureVisitor>(Context), 5541 Variable(variable), Capturer(0) {} 5542 5543 VarDecl *Variable; 5544 Expr *Capturer; 5545 5546 void VisitDeclRefExpr(DeclRefExpr *ref) { 5547 if (ref->getDecl() == Variable && !Capturer) 5548 Capturer = ref; 5549 } 5550 5551 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) { 5552 if (Capturer) return; 5553 Visit(ref->getBase()); 5554 if (Capturer && ref->isFreeIvar()) 5555 Capturer = ref; 5556 } 5557 5558 void VisitBlockExpr(BlockExpr *block) { 5559 // Look inside nested blocks 5560 if (block->getBlockDecl()->capturesVariable(Variable)) 5561 Visit(block->getBlockDecl()->getBody()); 5562 } 5563 5564 void VisitOpaqueValueExpr(OpaqueValueExpr *OVE) { 5565 if (Capturer) return; 5566 if (OVE->getSourceExpr()) 5567 Visit(OVE->getSourceExpr()); 5568 } 5569 }; 5570} 5571 5572/// Check whether the given argument is a block which captures a 5573/// variable. 5574static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) { 5575 assert(owner.Variable && owner.Loc.isValid()); 5576 5577 e = e->IgnoreParenCasts(); 5578 5579 // Look through [^{...} copy] and Block_copy(^{...}). 5580 if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(e)) { 5581 Selector Cmd = ME->getSelector(); 5582 if (Cmd.isUnarySelector() && Cmd.getNameForSlot(0) == "copy") { 5583 e = ME->getInstanceReceiver(); 5584 if (!e) 5585 return 0; 5586 e = e->IgnoreParenCasts(); 5587 } 5588 } else if (CallExpr *CE = dyn_cast<CallExpr>(e)) { 5589 if (CE->getNumArgs() == 1) { 5590 FunctionDecl *Fn = dyn_cast_or_null<FunctionDecl>(CE->getCalleeDecl()); 5591 if (Fn) { 5592 const IdentifierInfo *FnI = Fn->getIdentifier(); 5593 if (FnI && FnI->isStr("_Block_copy")) { 5594 e = CE->getArg(0)->IgnoreParenCasts(); 5595 } 5596 } 5597 } 5598 } 5599 5600 BlockExpr *block = dyn_cast<BlockExpr>(e); 5601 if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable)) 5602 return 0; 5603 5604 FindCaptureVisitor visitor(S.Context, owner.Variable); 5605 visitor.Visit(block->getBlockDecl()->getBody()); 5606 return visitor.Capturer; 5607} 5608 5609static void diagnoseRetainCycle(Sema &S, Expr *capturer, 5610 RetainCycleOwner &owner) { 5611 assert(capturer); 5612 assert(owner.Variable && owner.Loc.isValid()); 5613 5614 S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle) 5615 << owner.Variable << capturer->getSourceRange(); 5616 S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner) 5617 << owner.Indirect << owner.Range; 5618} 5619 5620/// Check for a keyword selector that starts with the word 'add' or 5621/// 'set'. 5622static bool isSetterLikeSelector(Selector sel) { 5623 if (sel.isUnarySelector()) return false; 5624 5625 StringRef str = sel.getNameForSlot(0); 5626 while (!str.empty() && str.front() == '_') str = str.substr(1); 5627 if (str.startswith("set")) 5628 str = str.substr(3); 5629 else if (str.startswith("add")) { 5630 // Specially whitelist 'addOperationWithBlock:'. 5631 if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock")) 5632 return false; 5633 str = str.substr(3); 5634 } 5635 else 5636 return false; 5637 5638 if (str.empty()) return true; 5639 return !islower(str.front()); 5640} 5641 5642/// Check a message send to see if it's likely to cause a retain cycle. 5643void Sema::checkRetainCycles(ObjCMessageExpr *msg) { 5644 // Only check instance methods whose selector looks like a setter. 5645 if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector())) 5646 return; 5647 5648 // Try to find a variable that the receiver is strongly owned by. 5649 RetainCycleOwner owner; 5650 if (msg->getReceiverKind() == ObjCMessageExpr::Instance) { 5651 if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner)) 5652 return; 5653 } else { 5654 assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance); 5655 owner.Variable = getCurMethodDecl()->getSelfDecl(); 5656 owner.Loc = msg->getSuperLoc(); 5657 owner.Range = msg->getSuperLoc(); 5658 } 5659 5660 // Check whether the receiver is captured by any of the arguments. 5661 for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i) 5662 if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner)) 5663 return diagnoseRetainCycle(*this, capturer, owner); 5664} 5665 5666/// Check a property assign to see if it's likely to cause a retain cycle. 5667void Sema::checkRetainCycles(Expr *receiver, Expr *argument) { 5668 RetainCycleOwner owner; 5669 if (!findRetainCycleOwner(*this, receiver, owner)) 5670 return; 5671 5672 if (Expr *capturer = findCapturingExpr(*this, argument, owner)) 5673 diagnoseRetainCycle(*this, capturer, owner); 5674} 5675 5676void Sema::checkRetainCycles(VarDecl *Var, Expr *Init) { 5677 RetainCycleOwner Owner; 5678 if (!considerVariable(Var, /*DeclRefExpr=*/0, Owner)) 5679 return; 5680 5681 // Because we don't have an expression for the variable, we have to set the 5682 // location explicitly here. 5683 Owner.Loc = Var->getLocation(); 5684 Owner.Range = Var->getSourceRange(); 5685 5686 if (Expr *Capturer = findCapturingExpr(*this, Init, Owner)) 5687 diagnoseRetainCycle(*this, Capturer, Owner); 5688} 5689 5690bool Sema::checkUnsafeAssigns(SourceLocation Loc, 5691 QualType LHS, Expr *RHS) { 5692 Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime(); 5693 if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone) 5694 return false; 5695 // strip off any implicit cast added to get to the one arc-specific 5696 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 5697 if (cast->getCastKind() == CK_ARCConsumeObject) { 5698 Diag(Loc, diag::warn_arc_retained_assign) 5699 << (LT == Qualifiers::OCL_ExplicitNone) << 1 5700 << RHS->getSourceRange(); 5701 return true; 5702 } 5703 RHS = cast->getSubExpr(); 5704 } 5705 return false; 5706} 5707 5708void Sema::checkUnsafeExprAssigns(SourceLocation Loc, 5709 Expr *LHS, Expr *RHS) { 5710 QualType LHSType; 5711 // PropertyRef on LHS type need be directly obtained from 5712 // its declaration as it has a PsuedoType. 5713 ObjCPropertyRefExpr *PRE 5714 = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens()); 5715 if (PRE && !PRE->isImplicitProperty()) { 5716 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 5717 if (PD) 5718 LHSType = PD->getType(); 5719 } 5720 5721 if (LHSType.isNull()) 5722 LHSType = LHS->getType(); 5723 5724 Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime(); 5725 5726 if (LT == Qualifiers::OCL_Weak) { 5727 DiagnosticsEngine::Level Level = 5728 Diags.getDiagnosticLevel(diag::warn_arc_repeated_use_of_weak, Loc); 5729 if (Level != DiagnosticsEngine::Ignored) 5730 getCurFunction()->markSafeWeakUse(LHS); 5731 } 5732 5733 if (checkUnsafeAssigns(Loc, LHSType, RHS)) 5734 return; 5735 5736 // FIXME. Check for other life times. 5737 if (LT != Qualifiers::OCL_None) 5738 return; 5739 5740 if (PRE) { 5741 if (PRE->isImplicitProperty()) 5742 return; 5743 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 5744 if (!PD) 5745 return; 5746 5747 unsigned Attributes = PD->getPropertyAttributes(); 5748 if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) { 5749 // when 'assign' attribute was not explicitly specified 5750 // by user, ignore it and rely on property type itself 5751 // for lifetime info. 5752 unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten(); 5753 if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) && 5754 LHSType->isObjCRetainableType()) 5755 return; 5756 5757 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 5758 if (cast->getCastKind() == CK_ARCConsumeObject) { 5759 Diag(Loc, diag::warn_arc_retained_property_assign) 5760 << RHS->getSourceRange(); 5761 return; 5762 } 5763 RHS = cast->getSubExpr(); 5764 } 5765 } 5766 else if (Attributes & ObjCPropertyDecl::OBJC_PR_weak) { 5767 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 5768 if (cast->getCastKind() == CK_ARCConsumeObject) { 5769 Diag(Loc, diag::warn_arc_retained_assign) 5770 << 0 << 0<< RHS->getSourceRange(); 5771 return; 5772 } 5773 RHS = cast->getSubExpr(); 5774 } 5775 } 5776 } 5777} 5778 5779//===--- CHECK: Empty statement body (-Wempty-body) ---------------------===// 5780 5781namespace { 5782bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr, 5783 SourceLocation StmtLoc, 5784 const NullStmt *Body) { 5785 // Do not warn if the body is a macro that expands to nothing, e.g: 5786 // 5787 // #define CALL(x) 5788 // if (condition) 5789 // CALL(0); 5790 // 5791 if (Body->hasLeadingEmptyMacro()) 5792 return false; 5793 5794 // Get line numbers of statement and body. 5795 bool StmtLineInvalid; 5796 unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc, 5797 &StmtLineInvalid); 5798 if (StmtLineInvalid) 5799 return false; 5800 5801 bool BodyLineInvalid; 5802 unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(), 5803 &BodyLineInvalid); 5804 if (BodyLineInvalid) 5805 return false; 5806 5807 // Warn if null statement and body are on the same line. 5808 if (StmtLine != BodyLine) 5809 return false; 5810 5811 return true; 5812} 5813} // Unnamed namespace 5814 5815void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc, 5816 const Stmt *Body, 5817 unsigned DiagID) { 5818 // Since this is a syntactic check, don't emit diagnostic for template 5819 // instantiations, this just adds noise. 5820 if (CurrentInstantiationScope) 5821 return; 5822 5823 // The body should be a null statement. 5824 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 5825 if (!NBody) 5826 return; 5827 5828 // Do the usual checks. 5829 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 5830 return; 5831 5832 Diag(NBody->getSemiLoc(), DiagID); 5833 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 5834} 5835 5836void Sema::DiagnoseEmptyLoopBody(const Stmt *S, 5837 const Stmt *PossibleBody) { 5838 assert(!CurrentInstantiationScope); // Ensured by caller 5839 5840 SourceLocation StmtLoc; 5841 const Stmt *Body; 5842 unsigned DiagID; 5843 if (const ForStmt *FS = dyn_cast<ForStmt>(S)) { 5844 StmtLoc = FS->getRParenLoc(); 5845 Body = FS->getBody(); 5846 DiagID = diag::warn_empty_for_body; 5847 } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) { 5848 StmtLoc = WS->getCond()->getSourceRange().getEnd(); 5849 Body = WS->getBody(); 5850 DiagID = diag::warn_empty_while_body; 5851 } else 5852 return; // Neither `for' nor `while'. 5853 5854 // The body should be a null statement. 5855 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 5856 if (!NBody) 5857 return; 5858 5859 // Skip expensive checks if diagnostic is disabled. 5860 if (Diags.getDiagnosticLevel(DiagID, NBody->getSemiLoc()) == 5861 DiagnosticsEngine::Ignored) 5862 return; 5863 5864 // Do the usual checks. 5865 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 5866 return; 5867 5868 // `for(...);' and `while(...);' are popular idioms, so in order to keep 5869 // noise level low, emit diagnostics only if for/while is followed by a 5870 // CompoundStmt, e.g.: 5871 // for (int i = 0; i < n; i++); 5872 // { 5873 // a(i); 5874 // } 5875 // or if for/while is followed by a statement with more indentation 5876 // than for/while itself: 5877 // for (int i = 0; i < n; i++); 5878 // a(i); 5879 bool ProbableTypo = isa<CompoundStmt>(PossibleBody); 5880 if (!ProbableTypo) { 5881 bool BodyColInvalid; 5882 unsigned BodyCol = SourceMgr.getPresumedColumnNumber( 5883 PossibleBody->getLocStart(), 5884 &BodyColInvalid); 5885 if (BodyColInvalid) 5886 return; 5887 5888 bool StmtColInvalid; 5889 unsigned StmtCol = SourceMgr.getPresumedColumnNumber( 5890 S->getLocStart(), 5891 &StmtColInvalid); 5892 if (StmtColInvalid) 5893 return; 5894 5895 if (BodyCol > StmtCol) 5896 ProbableTypo = true; 5897 } 5898 5899 if (ProbableTypo) { 5900 Diag(NBody->getSemiLoc(), DiagID); 5901 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 5902 } 5903} 5904 5905//===--- Layout compatibility ----------------------------------------------// 5906 5907namespace { 5908 5909bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2); 5910 5911/// \brief Check if two enumeration types are layout-compatible. 5912bool isLayoutCompatible(ASTContext &C, EnumDecl *ED1, EnumDecl *ED2) { 5913 // C++11 [dcl.enum] p8: 5914 // Two enumeration types are layout-compatible if they have the same 5915 // underlying type. 5916 return ED1->isComplete() && ED2->isComplete() && 5917 C.hasSameType(ED1->getIntegerType(), ED2->getIntegerType()); 5918} 5919 5920/// \brief Check if two fields are layout-compatible. 5921bool isLayoutCompatible(ASTContext &C, FieldDecl *Field1, FieldDecl *Field2) { 5922 if (!isLayoutCompatible(C, Field1->getType(), Field2->getType())) 5923 return false; 5924 5925 if (Field1->isBitField() != Field2->isBitField()) 5926 return false; 5927 5928 if (Field1->isBitField()) { 5929 // Make sure that the bit-fields are the same length. 5930 unsigned Bits1 = Field1->getBitWidthValue(C); 5931 unsigned Bits2 = Field2->getBitWidthValue(C); 5932 5933 if (Bits1 != Bits2) 5934 return false; 5935 } 5936 5937 return true; 5938} 5939 5940/// \brief Check if two standard-layout structs are layout-compatible. 5941/// (C++11 [class.mem] p17) 5942bool isLayoutCompatibleStruct(ASTContext &C, 5943 RecordDecl *RD1, 5944 RecordDecl *RD2) { 5945 // If both records are C++ classes, check that base classes match. 5946 if (const CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(RD1)) { 5947 // If one of records is a CXXRecordDecl we are in C++ mode, 5948 // thus the other one is a CXXRecordDecl, too. 5949 const CXXRecordDecl *D2CXX = cast<CXXRecordDecl>(RD2); 5950 // Check number of base classes. 5951 if (D1CXX->getNumBases() != D2CXX->getNumBases()) 5952 return false; 5953 5954 // Check the base classes. 5955 for (CXXRecordDecl::base_class_const_iterator 5956 Base1 = D1CXX->bases_begin(), 5957 BaseEnd1 = D1CXX->bases_end(), 5958 Base2 = D2CXX->bases_begin(); 5959 Base1 != BaseEnd1; 5960 ++Base1, ++Base2) { 5961 if (!isLayoutCompatible(C, Base1->getType(), Base2->getType())) 5962 return false; 5963 } 5964 } else if (const CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(RD2)) { 5965 // If only RD2 is a C++ class, it should have zero base classes. 5966 if (D2CXX->getNumBases() > 0) 5967 return false; 5968 } 5969 5970 // Check the fields. 5971 RecordDecl::field_iterator Field2 = RD2->field_begin(), 5972 Field2End = RD2->field_end(), 5973 Field1 = RD1->field_begin(), 5974 Field1End = RD1->field_end(); 5975 for ( ; Field1 != Field1End && Field2 != Field2End; ++Field1, ++Field2) { 5976 if (!isLayoutCompatible(C, *Field1, *Field2)) 5977 return false; 5978 } 5979 if (Field1 != Field1End || Field2 != Field2End) 5980 return false; 5981 5982 return true; 5983} 5984 5985/// \brief Check if two standard-layout unions are layout-compatible. 5986/// (C++11 [class.mem] p18) 5987bool isLayoutCompatibleUnion(ASTContext &C, 5988 RecordDecl *RD1, 5989 RecordDecl *RD2) { 5990 llvm::SmallPtrSet<FieldDecl *, 8> UnmatchedFields; 5991 for (RecordDecl::field_iterator Field2 = RD2->field_begin(), 5992 Field2End = RD2->field_end(); 5993 Field2 != Field2End; ++Field2) { 5994 UnmatchedFields.insert(*Field2); 5995 } 5996 5997 for (RecordDecl::field_iterator Field1 = RD1->field_begin(), 5998 Field1End = RD1->field_end(); 5999 Field1 != Field1End; ++Field1) { 6000 llvm::SmallPtrSet<FieldDecl *, 8>::iterator 6001 I = UnmatchedFields.begin(), 6002 E = UnmatchedFields.end(); 6003 6004 for ( ; I != E; ++I) { 6005 if (isLayoutCompatible(C, *Field1, *I)) { 6006 bool Result = UnmatchedFields.erase(*I); 6007 (void) Result; 6008 assert(Result); 6009 break; 6010 } 6011 } 6012 if (I == E) 6013 return false; 6014 } 6015 6016 return UnmatchedFields.empty(); 6017} 6018 6019bool isLayoutCompatible(ASTContext &C, RecordDecl *RD1, RecordDecl *RD2) { 6020 if (RD1->isUnion() != RD2->isUnion()) 6021 return false; 6022 6023 if (RD1->isUnion()) 6024 return isLayoutCompatibleUnion(C, RD1, RD2); 6025 else 6026 return isLayoutCompatibleStruct(C, RD1, RD2); 6027} 6028 6029/// \brief Check if two types are layout-compatible in C++11 sense. 6030bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2) { 6031 if (T1.isNull() || T2.isNull()) 6032 return false; 6033 6034 // C++11 [basic.types] p11: 6035 // If two types T1 and T2 are the same type, then T1 and T2 are 6036 // layout-compatible types. 6037 if (C.hasSameType(T1, T2)) 6038 return true; 6039 6040 T1 = T1.getCanonicalType().getUnqualifiedType(); 6041 T2 = T2.getCanonicalType().getUnqualifiedType(); 6042 6043 const Type::TypeClass TC1 = T1->getTypeClass(); 6044 const Type::TypeClass TC2 = T2->getTypeClass(); 6045 6046 if (TC1 != TC2) 6047 return false; 6048 6049 if (TC1 == Type::Enum) { 6050 return isLayoutCompatible(C, 6051 cast<EnumType>(T1)->getDecl(), 6052 cast<EnumType>(T2)->getDecl()); 6053 } else if (TC1 == Type::Record) { 6054 if (!T1->isStandardLayoutType() || !T2->isStandardLayoutType()) 6055 return false; 6056 6057 return isLayoutCompatible(C, 6058 cast<RecordType>(T1)->getDecl(), 6059 cast<RecordType>(T2)->getDecl()); 6060 } 6061 6062 return false; 6063} 6064} 6065 6066//===--- CHECK: pointer_with_type_tag attribute: datatypes should match ----// 6067 6068namespace { 6069/// \brief Given a type tag expression find the type tag itself. 6070/// 6071/// \param TypeExpr Type tag expression, as it appears in user's code. 6072/// 6073/// \param VD Declaration of an identifier that appears in a type tag. 6074/// 6075/// \param MagicValue Type tag magic value. 6076bool FindTypeTagExpr(const Expr *TypeExpr, const ASTContext &Ctx, 6077 const ValueDecl **VD, uint64_t *MagicValue) { 6078 while(true) { 6079 if (!TypeExpr) 6080 return false; 6081 6082 TypeExpr = TypeExpr->IgnoreParenImpCasts()->IgnoreParenCasts(); 6083 6084 switch (TypeExpr->getStmtClass()) { 6085 case Stmt::UnaryOperatorClass: { 6086 const UnaryOperator *UO = cast<UnaryOperator>(TypeExpr); 6087 if (UO->getOpcode() == UO_AddrOf || UO->getOpcode() == UO_Deref) { 6088 TypeExpr = UO->getSubExpr(); 6089 continue; 6090 } 6091 return false; 6092 } 6093 6094 case Stmt::DeclRefExprClass: { 6095 const DeclRefExpr *DRE = cast<DeclRefExpr>(TypeExpr); 6096 *VD = DRE->getDecl(); 6097 return true; 6098 } 6099 6100 case Stmt::IntegerLiteralClass: { 6101 const IntegerLiteral *IL = cast<IntegerLiteral>(TypeExpr); 6102 llvm::APInt MagicValueAPInt = IL->getValue(); 6103 if (MagicValueAPInt.getActiveBits() <= 64) { 6104 *MagicValue = MagicValueAPInt.getZExtValue(); 6105 return true; 6106 } else 6107 return false; 6108 } 6109 6110 case Stmt::BinaryConditionalOperatorClass: 6111 case Stmt::ConditionalOperatorClass: { 6112 const AbstractConditionalOperator *ACO = 6113 cast<AbstractConditionalOperator>(TypeExpr); 6114 bool Result; 6115 if (ACO->getCond()->EvaluateAsBooleanCondition(Result, Ctx)) { 6116 if (Result) 6117 TypeExpr = ACO->getTrueExpr(); 6118 else 6119 TypeExpr = ACO->getFalseExpr(); 6120 continue; 6121 } 6122 return false; 6123 } 6124 6125 case Stmt::BinaryOperatorClass: { 6126 const BinaryOperator *BO = cast<BinaryOperator>(TypeExpr); 6127 if (BO->getOpcode() == BO_Comma) { 6128 TypeExpr = BO->getRHS(); 6129 continue; 6130 } 6131 return false; 6132 } 6133 6134 default: 6135 return false; 6136 } 6137 } 6138} 6139 6140/// \brief Retrieve the C type corresponding to type tag TypeExpr. 6141/// 6142/// \param TypeExpr Expression that specifies a type tag. 6143/// 6144/// \param MagicValues Registered magic values. 6145/// 6146/// \param FoundWrongKind Set to true if a type tag was found, but of a wrong 6147/// kind. 6148/// 6149/// \param TypeInfo Information about the corresponding C type. 6150/// 6151/// \returns true if the corresponding C type was found. 6152bool GetMatchingCType( 6153 const IdentifierInfo *ArgumentKind, 6154 const Expr *TypeExpr, const ASTContext &Ctx, 6155 const llvm::DenseMap<Sema::TypeTagMagicValue, 6156 Sema::TypeTagData> *MagicValues, 6157 bool &FoundWrongKind, 6158 Sema::TypeTagData &TypeInfo) { 6159 FoundWrongKind = false; 6160 6161 // Variable declaration that has type_tag_for_datatype attribute. 6162 const ValueDecl *VD = NULL; 6163 6164 uint64_t MagicValue; 6165 6166 if (!FindTypeTagExpr(TypeExpr, Ctx, &VD, &MagicValue)) 6167 return false; 6168 6169 if (VD) { 6170 for (specific_attr_iterator<TypeTagForDatatypeAttr> 6171 I = VD->specific_attr_begin<TypeTagForDatatypeAttr>(), 6172 E = VD->specific_attr_end<TypeTagForDatatypeAttr>(); 6173 I != E; ++I) { 6174 if (I->getArgumentKind() != ArgumentKind) { 6175 FoundWrongKind = true; 6176 return false; 6177 } 6178 TypeInfo.Type = I->getMatchingCType(); 6179 TypeInfo.LayoutCompatible = I->getLayoutCompatible(); 6180 TypeInfo.MustBeNull = I->getMustBeNull(); 6181 return true; 6182 } 6183 return false; 6184 } 6185 6186 if (!MagicValues) 6187 return false; 6188 6189 llvm::DenseMap<Sema::TypeTagMagicValue, 6190 Sema::TypeTagData>::const_iterator I = 6191 MagicValues->find(std::make_pair(ArgumentKind, MagicValue)); 6192 if (I == MagicValues->end()) 6193 return false; 6194 6195 TypeInfo = I->second; 6196 return true; 6197} 6198} // unnamed namespace 6199 6200void Sema::RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind, 6201 uint64_t MagicValue, QualType Type, 6202 bool LayoutCompatible, 6203 bool MustBeNull) { 6204 if (!TypeTagForDatatypeMagicValues) 6205 TypeTagForDatatypeMagicValues.reset( 6206 new llvm::DenseMap<TypeTagMagicValue, TypeTagData>); 6207 6208 TypeTagMagicValue Magic(ArgumentKind, MagicValue); 6209 (*TypeTagForDatatypeMagicValues)[Magic] = 6210 TypeTagData(Type, LayoutCompatible, MustBeNull); 6211} 6212 6213namespace { 6214bool IsSameCharType(QualType T1, QualType T2) { 6215 const BuiltinType *BT1 = T1->getAs<BuiltinType>(); 6216 if (!BT1) 6217 return false; 6218 6219 const BuiltinType *BT2 = T2->getAs<BuiltinType>(); 6220 if (!BT2) 6221 return false; 6222 6223 BuiltinType::Kind T1Kind = BT1->getKind(); 6224 BuiltinType::Kind T2Kind = BT2->getKind(); 6225 6226 return (T1Kind == BuiltinType::SChar && T2Kind == BuiltinType::Char_S) || 6227 (T1Kind == BuiltinType::UChar && T2Kind == BuiltinType::Char_U) || 6228 (T1Kind == BuiltinType::Char_U && T2Kind == BuiltinType::UChar) || 6229 (T1Kind == BuiltinType::Char_S && T2Kind == BuiltinType::SChar); 6230} 6231} // unnamed namespace 6232 6233void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr, 6234 const Expr * const *ExprArgs) { 6235 const IdentifierInfo *ArgumentKind = Attr->getArgumentKind(); 6236 bool IsPointerAttr = Attr->getIsPointer(); 6237 6238 const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()]; 6239 bool FoundWrongKind; 6240 TypeTagData TypeInfo; 6241 if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context, 6242 TypeTagForDatatypeMagicValues.get(), 6243 FoundWrongKind, TypeInfo)) { 6244 if (FoundWrongKind) 6245 Diag(TypeTagExpr->getExprLoc(), 6246 diag::warn_type_tag_for_datatype_wrong_kind) 6247 << TypeTagExpr->getSourceRange(); 6248 return; 6249 } 6250 6251 const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()]; 6252 if (IsPointerAttr) { 6253 // Skip implicit cast of pointer to `void *' (as a function argument). 6254 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr)) 6255 if (ICE->getType()->isVoidPointerType() && 6256 ICE->getCastKind() == CK_BitCast) 6257 ArgumentExpr = ICE->getSubExpr(); 6258 } 6259 QualType ArgumentType = ArgumentExpr->getType(); 6260 6261 // Passing a `void*' pointer shouldn't trigger a warning. 6262 if (IsPointerAttr && ArgumentType->isVoidPointerType()) 6263 return; 6264 6265 if (TypeInfo.MustBeNull) { 6266 // Type tag with matching void type requires a null pointer. 6267 if (!ArgumentExpr->isNullPointerConstant(Context, 6268 Expr::NPC_ValueDependentIsNotNull)) { 6269 Diag(ArgumentExpr->getExprLoc(), 6270 diag::warn_type_safety_null_pointer_required) 6271 << ArgumentKind->getName() 6272 << ArgumentExpr->getSourceRange() 6273 << TypeTagExpr->getSourceRange(); 6274 } 6275 return; 6276 } 6277 6278 QualType RequiredType = TypeInfo.Type; 6279 if (IsPointerAttr) 6280 RequiredType = Context.getPointerType(RequiredType); 6281 6282 bool mismatch = false; 6283 if (!TypeInfo.LayoutCompatible) { 6284 mismatch = !Context.hasSameType(ArgumentType, RequiredType); 6285 6286 // C++11 [basic.fundamental] p1: 6287 // Plain char, signed char, and unsigned char are three distinct types. 6288 // 6289 // But we treat plain `char' as equivalent to `signed char' or `unsigned 6290 // char' depending on the current char signedness mode. 6291 if (mismatch) 6292 if ((IsPointerAttr && IsSameCharType(ArgumentType->getPointeeType(), 6293 RequiredType->getPointeeType())) || 6294 (!IsPointerAttr && IsSameCharType(ArgumentType, RequiredType))) 6295 mismatch = false; 6296 } else 6297 if (IsPointerAttr) 6298 mismatch = !isLayoutCompatible(Context, 6299 ArgumentType->getPointeeType(), 6300 RequiredType->getPointeeType()); 6301 else 6302 mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType); 6303 6304 if (mismatch) 6305 Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch) 6306 << ArgumentType << ArgumentKind->getName() 6307 << TypeInfo.LayoutCompatible << RequiredType 6308 << ArgumentExpr->getSourceRange() 6309 << TypeTagExpr->getSourceRange(); 6310} 6311