1 //===--- CodeGenFunction.cpp - Emit LLVM Code from ASTs for a Function ----===// 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 coordinates the per-function state used while generating code. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "CodeGenFunction.h" 15 #include "CGCUDARuntime.h" 16 #include "CGCXXABI.h" 17 #include "CGDebugInfo.h" 18 #include "CodeGenModule.h" 19 #include "clang/AST/ASTContext.h" 20 #include "clang/AST/Decl.h" 21 #include "clang/AST/DeclCXX.h" 22 #include "clang/AST/StmtCXX.h" 23 #include "clang/Basic/TargetInfo.h" 24 #include "clang/Frontend/CodeGenOptions.h" 25 #include "llvm/IR/DataLayout.h" 26 #include "llvm/IR/Intrinsics.h" 27 #include "llvm/IR/MDBuilder.h" 28 #include "llvm/IR/Operator.h" 29 using namespace clang; 30 using namespace CodeGen; 31 32 CodeGenFunction::CodeGenFunction(CodeGenModule &cgm, bool suppressNewContext) 33 : CodeGenTypeCache(cgm), CGM(cgm), 34 Target(CGM.getContext().getTargetInfo()), 35 Builder(cgm.getModule().getContext()), 36 SanitizePerformTypeCheck(CGM.getSanOpts().Null | 37 CGM.getSanOpts().Alignment | 38 CGM.getSanOpts().ObjectSize | 39 CGM.getSanOpts().Vptr), 40 SanOpts(&CGM.getSanOpts()), 41 AutoreleaseResult(false), BlockInfo(0), BlockPointer(0), 42 LambdaThisCaptureField(0), NormalCleanupDest(0), NextCleanupDestIndex(1), 43 FirstBlockInfo(0), EHResumeBlock(0), ExceptionSlot(0), EHSelectorSlot(0), 44 DebugInfo(0), DisableDebugInfo(false), DidCallStackSave(false), 45 IndirectBranch(0), SwitchInsn(0), CaseRangeBlock(0), UnreachableBlock(0), 46 CXXABIThisDecl(0), CXXABIThisValue(0), CXXThisValue(0), 47 CXXStructorImplicitParamDecl(0), CXXStructorImplicitParamValue(0), 48 OutermostConditional(0), TerminateLandingPad(0), 49 TerminateHandler(0), TrapBB(0) { 50 if (!suppressNewContext) 51 CGM.getCXXABI().getMangleContext().startNewFunction(); 52 53 llvm::FastMathFlags FMF; 54 if (CGM.getLangOpts().FastMath) 55 FMF.setUnsafeAlgebra(); 56 if (CGM.getLangOpts().FiniteMathOnly) { 57 FMF.setNoNaNs(); 58 FMF.setNoInfs(); 59 } 60 Builder.SetFastMathFlags(FMF); 61 } 62 63 CodeGenFunction::~CodeGenFunction() { 64 // If there are any unclaimed block infos, go ahead and destroy them 65 // now. This can happen if IR-gen gets clever and skips evaluating 66 // something. 67 if (FirstBlockInfo) 68 destroyBlockInfos(FirstBlockInfo); 69 } 70 71 72 llvm::Type *CodeGenFunction::ConvertTypeForMem(QualType T) { 73 return CGM.getTypes().ConvertTypeForMem(T); 74 } 75 76 llvm::Type *CodeGenFunction::ConvertType(QualType T) { 77 return CGM.getTypes().ConvertType(T); 78 } 79 80 TypeEvaluationKind CodeGenFunction::getEvaluationKind(QualType type) { 81 type = type.getCanonicalType(); 82 while (true) { 83 switch (type->getTypeClass()) { 84 #define TYPE(name, parent) 85 #define ABSTRACT_TYPE(name, parent) 86 #define NON_CANONICAL_TYPE(name, parent) case Type::name: 87 #define DEPENDENT_TYPE(name, parent) case Type::name: 88 #define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(name, parent) case Type::name: 89 #include "clang/AST/TypeNodes.def" 90 llvm_unreachable("non-canonical or dependent type in IR-generation"); 91 92 // Various scalar types. 93 case Type::Builtin: 94 case Type::Pointer: 95 case Type::BlockPointer: 96 case Type::LValueReference: 97 case Type::RValueReference: 98 case Type::MemberPointer: 99 case Type::Vector: 100 case Type::ExtVector: 101 case Type::FunctionProto: 102 case Type::FunctionNoProto: 103 case Type::Enum: 104 case Type::ObjCObjectPointer: 105 return TEK_Scalar; 106 107 // Complexes. 108 case Type::Complex: 109 return TEK_Complex; 110 111 // Arrays, records, and Objective-C objects. 112 case Type::ConstantArray: 113 case Type::IncompleteArray: 114 case Type::VariableArray: 115 case Type::Record: 116 case Type::ObjCObject: 117 case Type::ObjCInterface: 118 return TEK_Aggregate; 119 120 // We operate on atomic values according to their underlying type. 121 case Type::Atomic: 122 type = cast<AtomicType>(type)->getValueType(); 123 continue; 124 } 125 llvm_unreachable("unknown type kind!"); 126 } 127 } 128 129 void CodeGenFunction::EmitReturnBlock() { 130 // For cleanliness, we try to avoid emitting the return block for 131 // simple cases. 132 llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); 133 134 if (CurBB) { 135 assert(!CurBB->getTerminator() && "Unexpected terminated block."); 136 137 // We have a valid insert point, reuse it if it is empty or there are no 138 // explicit jumps to the return block. 139 if (CurBB->empty() || ReturnBlock.getBlock()->use_empty()) { 140 ReturnBlock.getBlock()->replaceAllUsesWith(CurBB); 141 delete ReturnBlock.getBlock(); 142 } else 143 EmitBlock(ReturnBlock.getBlock()); 144 return; 145 } 146 147 // Otherwise, if the return block is the target of a single direct 148 // branch then we can just put the code in that block instead. This 149 // cleans up functions which started with a unified return block. 150 if (ReturnBlock.getBlock()->hasOneUse()) { 151 llvm::BranchInst *BI = 152 dyn_cast<llvm::BranchInst>(*ReturnBlock.getBlock()->use_begin()); 153 if (BI && BI->isUnconditional() && 154 BI->getSuccessor(0) == ReturnBlock.getBlock()) { 155 // Reset insertion point, including debug location, and delete the 156 // branch. This is really subtle and only works because the next change 157 // in location will hit the caching in CGDebugInfo::EmitLocation and not 158 // override this. 159 Builder.SetCurrentDebugLocation(BI->getDebugLoc()); 160 Builder.SetInsertPoint(BI->getParent()); 161 BI->eraseFromParent(); 162 delete ReturnBlock.getBlock(); 163 return; 164 } 165 } 166 167 // FIXME: We are at an unreachable point, there is no reason to emit the block 168 // unless it has uses. However, we still need a place to put the debug 169 // region.end for now. 170 171 EmitBlock(ReturnBlock.getBlock()); 172 } 173 174 static void EmitIfUsed(CodeGenFunction &CGF, llvm::BasicBlock *BB) { 175 if (!BB) return; 176 if (!BB->use_empty()) 177 return CGF.CurFn->getBasicBlockList().push_back(BB); 178 delete BB; 179 } 180 181 void CodeGenFunction::FinishFunction(SourceLocation EndLoc) { 182 assert(BreakContinueStack.empty() && 183 "mismatched push/pop in break/continue stack!"); 184 185 if (CGDebugInfo *DI = getDebugInfo()) 186 DI->EmitLocation(Builder, EndLoc); 187 188 // Pop any cleanups that might have been associated with the 189 // parameters. Do this in whatever block we're currently in; it's 190 // important to do this before we enter the return block or return 191 // edges will be *really* confused. 192 if (EHStack.stable_begin() != PrologueCleanupDepth) 193 PopCleanupBlocks(PrologueCleanupDepth); 194 195 // Emit function epilog (to return). 196 EmitReturnBlock(); 197 198 if (ShouldInstrumentFunction()) 199 EmitFunctionInstrumentation("__cyg_profile_func_exit"); 200 201 // Emit debug descriptor for function end. 202 if (CGDebugInfo *DI = getDebugInfo()) { 203 DI->EmitFunctionEnd(Builder); 204 } 205 206 EmitFunctionEpilog(*CurFnInfo); 207 EmitEndEHSpec(CurCodeDecl); 208 209 assert(EHStack.empty() && 210 "did not remove all scopes from cleanup stack!"); 211 212 // If someone did an indirect goto, emit the indirect goto block at the end of 213 // the function. 214 if (IndirectBranch) { 215 EmitBlock(IndirectBranch->getParent()); 216 Builder.ClearInsertionPoint(); 217 } 218 219 // Remove the AllocaInsertPt instruction, which is just a convenience for us. 220 llvm::Instruction *Ptr = AllocaInsertPt; 221 AllocaInsertPt = 0; 222 Ptr->eraseFromParent(); 223 224 // If someone took the address of a label but never did an indirect goto, we 225 // made a zero entry PHI node, which is illegal, zap it now. 226 if (IndirectBranch) { 227 llvm::PHINode *PN = cast<llvm::PHINode>(IndirectBranch->getAddress()); 228 if (PN->getNumIncomingValues() == 0) { 229 PN->replaceAllUsesWith(llvm::UndefValue::get(PN->getType())); 230 PN->eraseFromParent(); 231 } 232 } 233 234 EmitIfUsed(*this, EHResumeBlock); 235 EmitIfUsed(*this, TerminateLandingPad); 236 EmitIfUsed(*this, TerminateHandler); 237 EmitIfUsed(*this, UnreachableBlock); 238 239 if (CGM.getCodeGenOpts().EmitDeclMetadata) 240 EmitDeclMetadata(); 241 } 242 243 /// ShouldInstrumentFunction - Return true if the current function should be 244 /// instrumented with __cyg_profile_func_* calls 245 bool CodeGenFunction::ShouldInstrumentFunction() { 246 if (!CGM.getCodeGenOpts().InstrumentFunctions) 247 return false; 248 if (!CurFuncDecl || CurFuncDecl->hasAttr<NoInstrumentFunctionAttr>()) 249 return false; 250 return true; 251 } 252 253 /// EmitFunctionInstrumentation - Emit LLVM code to call the specified 254 /// instrumentation function with the current function and the call site, if 255 /// function instrumentation is enabled. 256 void CodeGenFunction::EmitFunctionInstrumentation(const char *Fn) { 257 // void __cyg_profile_func_{enter,exit} (void *this_fn, void *call_site); 258 llvm::PointerType *PointerTy = Int8PtrTy; 259 llvm::Type *ProfileFuncArgs[] = { PointerTy, PointerTy }; 260 llvm::FunctionType *FunctionTy = 261 llvm::FunctionType::get(VoidTy, ProfileFuncArgs, false); 262 263 llvm::Constant *F = CGM.CreateRuntimeFunction(FunctionTy, Fn); 264 llvm::CallInst *CallSite = Builder.CreateCall( 265 CGM.getIntrinsic(llvm::Intrinsic::returnaddress), 266 llvm::ConstantInt::get(Int32Ty, 0), 267 "callsite"); 268 269 llvm::Value *args[] = { 270 llvm::ConstantExpr::getBitCast(CurFn, PointerTy), 271 CallSite 272 }; 273 274 EmitNounwindRuntimeCall(F, args); 275 } 276 277 void CodeGenFunction::EmitMCountInstrumentation() { 278 llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false); 279 280 llvm::Constant *MCountFn = CGM.CreateRuntimeFunction(FTy, 281 Target.getMCountName()); 282 EmitNounwindRuntimeCall(MCountFn); 283 } 284 285 // OpenCL v1.2 s5.6.4.6 allows the compiler to store kernel argument 286 // information in the program executable. The argument information stored 287 // includes the argument name, its type, the address and access qualifiers used. 288 // FIXME: Add type, address, and access qualifiers. 289 static void GenOpenCLArgMetadata(const FunctionDecl *FD, llvm::Function *Fn, 290 CodeGenModule &CGM,llvm::LLVMContext &Context, 291 SmallVector <llvm::Value*, 5> &kernelMDArgs) { 292 293 // Create MDNodes that represents the kernel arg metadata. 294 // Each MDNode is a list in the form of "key", N number of values which is 295 // the same number of values as their are kernel arguments. 296 297 // MDNode for the kernel argument names. 298 SmallVector<llvm::Value*, 8> argNames; 299 argNames.push_back(llvm::MDString::get(Context, "kernel_arg_name")); 300 301 for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i) { 302 const ParmVarDecl *parm = FD->getParamDecl(i); 303 304 // Get argument name. 305 argNames.push_back(llvm::MDString::get(Context, parm->getName())); 306 307 } 308 // Add MDNode to the list of all metadata. 309 kernelMDArgs.push_back(llvm::MDNode::get(Context, argNames)); 310 } 311 312 void CodeGenFunction::EmitOpenCLKernelMetadata(const FunctionDecl *FD, 313 llvm::Function *Fn) 314 { 315 if (!FD->hasAttr<OpenCLKernelAttr>()) 316 return; 317 318 llvm::LLVMContext &Context = getLLVMContext(); 319 320 SmallVector <llvm::Value*, 5> kernelMDArgs; 321 kernelMDArgs.push_back(Fn); 322 323 if (CGM.getCodeGenOpts().EmitOpenCLArgMetadata) 324 GenOpenCLArgMetadata(FD, Fn, CGM, Context, kernelMDArgs); 325 326 if (FD->hasAttr<VecTypeHintAttr>()) { 327 VecTypeHintAttr *attr = FD->getAttr<VecTypeHintAttr>(); 328 QualType hintQTy = attr->getTypeHint(); 329 const ExtVectorType *hintEltQTy = hintQTy->getAs<ExtVectorType>(); 330 bool isSignedInteger = 331 hintQTy->isSignedIntegerType() || 332 (hintEltQTy && hintEltQTy->getElementType()->isSignedIntegerType()); 333 llvm::Value *attrMDArgs[] = { 334 llvm::MDString::get(Context, "vec_type_hint"), 335 llvm::UndefValue::get(CGM.getTypes().ConvertType(attr->getTypeHint())), 336 llvm::ConstantInt::get( 337 llvm::IntegerType::get(Context, 32), 338 llvm::APInt(32, (uint64_t)(isSignedInteger ? 1 : 0))) 339 }; 340 kernelMDArgs.push_back(llvm::MDNode::get(Context, attrMDArgs)); 341 } 342 343 if (FD->hasAttr<WorkGroupSizeHintAttr>()) { 344 WorkGroupSizeHintAttr *attr = FD->getAttr<WorkGroupSizeHintAttr>(); 345 llvm::Value *attrMDArgs[] = { 346 llvm::MDString::get(Context, "work_group_size_hint"), 347 Builder.getInt32(attr->getXDim()), 348 Builder.getInt32(attr->getYDim()), 349 Builder.getInt32(attr->getZDim()) 350 }; 351 kernelMDArgs.push_back(llvm::MDNode::get(Context, attrMDArgs)); 352 } 353 354 if (FD->hasAttr<ReqdWorkGroupSizeAttr>()) { 355 ReqdWorkGroupSizeAttr *attr = FD->getAttr<ReqdWorkGroupSizeAttr>(); 356 llvm::Value *attrMDArgs[] = { 357 llvm::MDString::get(Context, "reqd_work_group_size"), 358 Builder.getInt32(attr->getXDim()), 359 Builder.getInt32(attr->getYDim()), 360 Builder.getInt32(attr->getZDim()) 361 }; 362 kernelMDArgs.push_back(llvm::MDNode::get(Context, attrMDArgs)); 363 } 364 365 llvm::MDNode *kernelMDNode = llvm::MDNode::get(Context, kernelMDArgs); 366 llvm::NamedMDNode *OpenCLKernelMetadata = 367 CGM.getModule().getOrInsertNamedMetadata("opencl.kernels"); 368 OpenCLKernelMetadata->addOperand(kernelMDNode); 369 } 370 371 void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy, 372 llvm::Function *Fn, 373 const CGFunctionInfo &FnInfo, 374 const FunctionArgList &Args, 375 SourceLocation StartLoc) { 376 const Decl *D = GD.getDecl(); 377 378 DidCallStackSave = false; 379 CurCodeDecl = CurFuncDecl = D; 380 FnRetTy = RetTy; 381 CurFn = Fn; 382 CurFnInfo = &FnInfo; 383 assert(CurFn->isDeclaration() && "Function already has body?"); 384 385 if (CGM.getSanitizerBlacklist().isIn(*Fn)) { 386 SanOpts = &SanitizerOptions::Disabled; 387 SanitizePerformTypeCheck = false; 388 } 389 390 // Pass inline keyword to optimizer if it appears explicitly on any 391 // declaration. 392 if (!CGM.getCodeGenOpts().NoInline) 393 if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) 394 for (FunctionDecl::redecl_iterator RI = FD->redecls_begin(), 395 RE = FD->redecls_end(); RI != RE; ++RI) 396 if (RI->isInlineSpecified()) { 397 Fn->addFnAttr(llvm::Attribute::InlineHint); 398 break; 399 } 400 401 if (getLangOpts().OpenCL) { 402 // Add metadata for a kernel function. 403 if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) 404 EmitOpenCLKernelMetadata(FD, Fn); 405 } 406 407 llvm::BasicBlock *EntryBB = createBasicBlock("entry", CurFn); 408 409 // Create a marker to make it easy to insert allocas into the entryblock 410 // later. Don't create this with the builder, because we don't want it 411 // folded. 412 llvm::Value *Undef = llvm::UndefValue::get(Int32Ty); 413 AllocaInsertPt = new llvm::BitCastInst(Undef, Int32Ty, "", EntryBB); 414 if (Builder.isNamePreserving()) 415 AllocaInsertPt->setName("allocapt"); 416 417 ReturnBlock = getJumpDestInCurrentScope("return"); 418 419 Builder.SetInsertPoint(EntryBB); 420 421 // Emit subprogram debug descriptor. 422 if (CGDebugInfo *DI = getDebugInfo()) { 423 SmallVector<QualType, 16> ArgTypes; 424 for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end(); 425 i != e; ++i) { 426 ArgTypes.push_back((*i)->getType()); 427 } 428 429 QualType FnType = 430 getContext().getFunctionType(RetTy, ArgTypes, 431 FunctionProtoType::ExtProtoInfo()); 432 433 DI->setLocation(StartLoc); 434 DI->EmitFunctionStart(GD, FnType, CurFn, Builder); 435 } 436 437 if (ShouldInstrumentFunction()) 438 EmitFunctionInstrumentation("__cyg_profile_func_enter"); 439 440 if (CGM.getCodeGenOpts().InstrumentForProfiling) 441 EmitMCountInstrumentation(); 442 443 if (RetTy->isVoidType()) { 444 // Void type; nothing to return. 445 ReturnValue = 0; 446 } else if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::Indirect && 447 !hasScalarEvaluationKind(CurFnInfo->getReturnType())) { 448 // Indirect aggregate return; emit returned value directly into sret slot. 449 // This reduces code size, and affects correctness in C++. 450 ReturnValue = CurFn->arg_begin(); 451 } else { 452 ReturnValue = CreateIRTemp(RetTy, "retval"); 453 454 // Tell the epilog emitter to autorelease the result. We do this 455 // now so that various specialized functions can suppress it 456 // during their IR-generation. 457 if (getLangOpts().ObjCAutoRefCount && 458 !CurFnInfo->isReturnsRetained() && 459 RetTy->isObjCRetainableType()) 460 AutoreleaseResult = true; 461 } 462 463 EmitStartEHSpec(CurCodeDecl); 464 465 PrologueCleanupDepth = EHStack.stable_begin(); 466 EmitFunctionProlog(*CurFnInfo, CurFn, Args); 467 468 if (D && isa<CXXMethodDecl>(D) && cast<CXXMethodDecl>(D)->isInstance()) { 469 CGM.getCXXABI().EmitInstanceFunctionProlog(*this); 470 const CXXMethodDecl *MD = cast<CXXMethodDecl>(D); 471 if (MD->getParent()->isLambda() && 472 MD->getOverloadedOperator() == OO_Call) { 473 // We're in a lambda; figure out the captures. 474 MD->getParent()->getCaptureFields(LambdaCaptureFields, 475 LambdaThisCaptureField); 476 if (LambdaThisCaptureField) { 477 // If this lambda captures this, load it. 478 QualType LambdaTagType = 479 getContext().getTagDeclType(LambdaThisCaptureField->getParent()); 480 LValue LambdaLV = MakeNaturalAlignAddrLValue(CXXABIThisValue, 481 LambdaTagType); 482 LValue ThisLValue = EmitLValueForField(LambdaLV, 483 LambdaThisCaptureField); 484 CXXThisValue = EmitLoadOfLValue(ThisLValue).getScalarVal(); 485 } 486 } else { 487 // Not in a lambda; just use 'this' from the method. 488 // FIXME: Should we generate a new load for each use of 'this'? The 489 // fast register allocator would be happier... 490 CXXThisValue = CXXABIThisValue; 491 } 492 } 493 494 // If any of the arguments have a variably modified type, make sure to 495 // emit the type size. 496 for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end(); 497 i != e; ++i) { 498 const VarDecl *VD = *i; 499 500 // Dig out the type as written from ParmVarDecls; it's unclear whether 501 // the standard (C99 6.9.1p10) requires this, but we're following the 502 // precedent set by gcc. 503 QualType Ty; 504 if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD)) 505 Ty = PVD->getOriginalType(); 506 else 507 Ty = VD->getType(); 508 509 if (Ty->isVariablyModifiedType()) 510 EmitVariablyModifiedType(Ty); 511 } 512 // Emit a location at the end of the prologue. 513 if (CGDebugInfo *DI = getDebugInfo()) 514 DI->EmitLocation(Builder, StartLoc); 515 } 516 517 void CodeGenFunction::EmitFunctionBody(FunctionArgList &Args) { 518 const FunctionDecl *FD = cast<FunctionDecl>(CurGD.getDecl()); 519 assert(FD->getBody()); 520 if (const CompoundStmt *S = dyn_cast<CompoundStmt>(FD->getBody())) 521 EmitCompoundStmtWithoutScope(*S); 522 else 523 EmitStmt(FD->getBody()); 524 } 525 526 /// Tries to mark the given function nounwind based on the 527 /// non-existence of any throwing calls within it. We believe this is 528 /// lightweight enough to do at -O0. 529 static void TryMarkNoThrow(llvm::Function *F) { 530 // LLVM treats 'nounwind' on a function as part of the type, so we 531 // can't do this on functions that can be overwritten. 532 if (F->mayBeOverridden()) return; 533 534 for (llvm::Function::iterator FI = F->begin(), FE = F->end(); FI != FE; ++FI) 535 for (llvm::BasicBlock::iterator 536 BI = FI->begin(), BE = FI->end(); BI != BE; ++BI) 537 if (llvm::CallInst *Call = dyn_cast<llvm::CallInst>(&*BI)) { 538 if (!Call->doesNotThrow()) 539 return; 540 } else if (isa<llvm::ResumeInst>(&*BI)) { 541 return; 542 } 543 F->setDoesNotThrow(); 544 } 545 546 void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn, 547 const CGFunctionInfo &FnInfo) { 548 const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); 549 550 // Check if we should generate debug info for this function. 551 if (!FD->hasAttr<NoDebugAttr>()) 552 maybeInitializeDebugInfo(); 553 554 FunctionArgList Args; 555 QualType ResTy = FD->getResultType(); 556 557 CurGD = GD; 558 if (isa<CXXMethodDecl>(FD) && cast<CXXMethodDecl>(FD)->isInstance()) 559 CGM.getCXXABI().BuildInstanceFunctionParams(*this, ResTy, Args); 560 561 for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i) 562 Args.push_back(FD->getParamDecl(i)); 563 564 SourceRange BodyRange; 565 if (Stmt *Body = FD->getBody()) BodyRange = Body->getSourceRange(); 566 567 // Emit the standard function prologue. 568 StartFunction(GD, ResTy, Fn, FnInfo, Args, BodyRange.getBegin()); 569 570 // Generate the body of the function. 571 if (isa<CXXDestructorDecl>(FD)) 572 EmitDestructorBody(Args); 573 else if (isa<CXXConstructorDecl>(FD)) 574 EmitConstructorBody(Args); 575 else if (getLangOpts().CUDA && 576 !CGM.getCodeGenOpts().CUDAIsDevice && 577 FD->hasAttr<CUDAGlobalAttr>()) 578 CGM.getCUDARuntime().EmitDeviceStubBody(*this, Args); 579 else if (isa<CXXConversionDecl>(FD) && 580 cast<CXXConversionDecl>(FD)->isLambdaToBlockPointerConversion()) { 581 // The lambda conversion to block pointer is special; the semantics can't be 582 // expressed in the AST, so IRGen needs to special-case it. 583 EmitLambdaToBlockPointerBody(Args); 584 } else if (isa<CXXMethodDecl>(FD) && 585 cast<CXXMethodDecl>(FD)->isLambdaStaticInvoker()) { 586 // The lambda "__invoke" function is special, because it forwards or 587 // clones the body of the function call operator (but is actually static). 588 EmitLambdaStaticInvokeFunction(cast<CXXMethodDecl>(FD)); 589 } else if (FD->isDefaulted() && isa<CXXMethodDecl>(FD) && 590 cast<CXXMethodDecl>(FD)->isCopyAssignmentOperator()) { 591 // Implicit copy-assignment gets the same special treatment as implicit 592 // copy-constructors. 593 emitImplicitAssignmentOperatorBody(Args); 594 } 595 else 596 EmitFunctionBody(Args); 597 598 // C++11 [stmt.return]p2: 599 // Flowing off the end of a function [...] results in undefined behavior in 600 // a value-returning function. 601 // C11 6.9.1p12: 602 // If the '}' that terminates a function is reached, and the value of the 603 // function call is used by the caller, the behavior is undefined. 604 if (getLangOpts().CPlusPlus && !FD->hasImplicitReturnZero() && 605 !FD->getResultType()->isVoidType() && Builder.GetInsertBlock()) { 606 if (SanOpts->Return) 607 EmitCheck(Builder.getFalse(), "missing_return", 608 EmitCheckSourceLocation(FD->getLocation()), 609 ArrayRef<llvm::Value *>(), CRK_Unrecoverable); 610 else if (CGM.getCodeGenOpts().OptimizationLevel == 0) 611 Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::trap)); 612 Builder.CreateUnreachable(); 613 Builder.ClearInsertionPoint(); 614 } 615 616 // Emit the standard function epilogue. 617 FinishFunction(BodyRange.getEnd()); 618 619 // If we haven't marked the function nothrow through other means, do 620 // a quick pass now to see if we can. 621 if (!CurFn->doesNotThrow()) 622 TryMarkNoThrow(CurFn); 623 } 624 625 /// ContainsLabel - Return true if the statement contains a label in it. If 626 /// this statement is not executed normally, it not containing a label means 627 /// that we can just remove the code. 628 bool CodeGenFunction::ContainsLabel(const Stmt *S, bool IgnoreCaseStmts) { 629 // Null statement, not a label! 630 if (S == 0) return false; 631 632 // If this is a label, we have to emit the code, consider something like: 633 // if (0) { ... foo: bar(); } goto foo; 634 // 635 // TODO: If anyone cared, we could track __label__'s, since we know that you 636 // can't jump to one from outside their declared region. 637 if (isa<LabelStmt>(S)) 638 return true; 639 640 // If this is a case/default statement, and we haven't seen a switch, we have 641 // to emit the code. 642 if (isa<SwitchCase>(S) && !IgnoreCaseStmts) 643 return true; 644 645 // If this is a switch statement, we want to ignore cases below it. 646 if (isa<SwitchStmt>(S)) 647 IgnoreCaseStmts = true; 648 649 // Scan subexpressions for verboten labels. 650 for (Stmt::const_child_range I = S->children(); I; ++I) 651 if (ContainsLabel(*I, IgnoreCaseStmts)) 652 return true; 653 654 return false; 655 } 656 657 /// containsBreak - Return true if the statement contains a break out of it. 658 /// If the statement (recursively) contains a switch or loop with a break 659 /// inside of it, this is fine. 660 bool CodeGenFunction::containsBreak(const Stmt *S) { 661 // Null statement, not a label! 662 if (S == 0) return false; 663 664 // If this is a switch or loop that defines its own break scope, then we can 665 // include it and anything inside of it. 666 if (isa<SwitchStmt>(S) || isa<WhileStmt>(S) || isa<DoStmt>(S) || 667 isa<ForStmt>(S)) 668 return false; 669 670 if (isa<BreakStmt>(S)) 671 return true; 672 673 // Scan subexpressions for verboten breaks. 674 for (Stmt::const_child_range I = S->children(); I; ++I) 675 if (containsBreak(*I)) 676 return true; 677 678 return false; 679 } 680 681 682 /// ConstantFoldsToSimpleInteger - If the specified expression does not fold 683 /// to a constant, or if it does but contains a label, return false. If it 684 /// constant folds return true and set the boolean result in Result. 685 bool CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond, 686 bool &ResultBool) { 687 llvm::APSInt ResultInt; 688 if (!ConstantFoldsToSimpleInteger(Cond, ResultInt)) 689 return false; 690 691 ResultBool = ResultInt.getBoolValue(); 692 return true; 693 } 694 695 /// ConstantFoldsToSimpleInteger - If the specified expression does not fold 696 /// to a constant, or if it does but contains a label, return false. If it 697 /// constant folds return true and set the folded value. 698 bool CodeGenFunction:: 699 ConstantFoldsToSimpleInteger(const Expr *Cond, llvm::APSInt &ResultInt) { 700 // FIXME: Rename and handle conversion of other evaluatable things 701 // to bool. 702 llvm::APSInt Int; 703 if (!Cond->EvaluateAsInt(Int, getContext())) 704 return false; // Not foldable, not integer or not fully evaluatable. 705 706 if (CodeGenFunction::ContainsLabel(Cond)) 707 return false; // Contains a label. 708 709 ResultInt = Int; 710 return true; 711 } 712 713 714 715 /// EmitBranchOnBoolExpr - Emit a branch on a boolean condition (e.g. for an if 716 /// statement) to the specified blocks. Based on the condition, this might try 717 /// to simplify the codegen of the conditional based on the branch. 718 /// 719 void CodeGenFunction::EmitBranchOnBoolExpr(const Expr *Cond, 720 llvm::BasicBlock *TrueBlock, 721 llvm::BasicBlock *FalseBlock) { 722 Cond = Cond->IgnoreParens(); 723 724 if (const BinaryOperator *CondBOp = dyn_cast<BinaryOperator>(Cond)) { 725 // Handle X && Y in a condition. 726 if (CondBOp->getOpcode() == BO_LAnd) { 727 // If we have "1 && X", simplify the code. "0 && X" would have constant 728 // folded if the case was simple enough. 729 bool ConstantBool = false; 730 if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) && 731 ConstantBool) { 732 // br(1 && X) -> br(X). 733 return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); 734 } 735 736 // If we have "X && 1", simplify the code to use an uncond branch. 737 // "X && 0" would have been constant folded to 0. 738 if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) && 739 ConstantBool) { 740 // br(X && 1) -> br(X). 741 return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock); 742 } 743 744 // Emit the LHS as a conditional. If the LHS conditional is false, we 745 // want to jump to the FalseBlock. 746 llvm::BasicBlock *LHSTrue = createBasicBlock("land.lhs.true"); 747 748 ConditionalEvaluation eval(*this); 749 EmitBranchOnBoolExpr(CondBOp->getLHS(), LHSTrue, FalseBlock); 750 EmitBlock(LHSTrue); 751 752 // Any temporaries created here are conditional. 753 eval.begin(*this); 754 EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); 755 eval.end(*this); 756 757 return; 758 } 759 760 if (CondBOp->getOpcode() == BO_LOr) { 761 // If we have "0 || X", simplify the code. "1 || X" would have constant 762 // folded if the case was simple enough. 763 bool ConstantBool = false; 764 if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) && 765 !ConstantBool) { 766 // br(0 || X) -> br(X). 767 return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); 768 } 769 770 // If we have "X || 0", simplify the code to use an uncond branch. 771 // "X || 1" would have been constant folded to 1. 772 if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) && 773 !ConstantBool) { 774 // br(X || 0) -> br(X). 775 return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock); 776 } 777 778 // Emit the LHS as a conditional. If the LHS conditional is true, we 779 // want to jump to the TrueBlock. 780 llvm::BasicBlock *LHSFalse = createBasicBlock("lor.lhs.false"); 781 782 ConditionalEvaluation eval(*this); 783 EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, LHSFalse); 784 EmitBlock(LHSFalse); 785 786 // Any temporaries created here are conditional. 787 eval.begin(*this); 788 EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); 789 eval.end(*this); 790 791 return; 792 } 793 } 794 795 if (const UnaryOperator *CondUOp = dyn_cast<UnaryOperator>(Cond)) { 796 // br(!x, t, f) -> br(x, f, t) 797 if (CondUOp->getOpcode() == UO_LNot) 798 return EmitBranchOnBoolExpr(CondUOp->getSubExpr(), FalseBlock, TrueBlock); 799 } 800 801 if (const ConditionalOperator *CondOp = dyn_cast<ConditionalOperator>(Cond)) { 802 // br(c ? x : y, t, f) -> br(c, br(x, t, f), br(y, t, f)) 803 llvm::BasicBlock *LHSBlock = createBasicBlock("cond.true"); 804 llvm::BasicBlock *RHSBlock = createBasicBlock("cond.false"); 805 806 ConditionalEvaluation cond(*this); 807 EmitBranchOnBoolExpr(CondOp->getCond(), LHSBlock, RHSBlock); 808 809 cond.begin(*this); 810 EmitBlock(LHSBlock); 811 EmitBranchOnBoolExpr(CondOp->getLHS(), TrueBlock, FalseBlock); 812 cond.end(*this); 813 814 cond.begin(*this); 815 EmitBlock(RHSBlock); 816 EmitBranchOnBoolExpr(CondOp->getRHS(), TrueBlock, FalseBlock); 817 cond.end(*this); 818 819 return; 820 } 821 822 // Emit the code with the fully general case. 823 llvm::Value *CondV = EvaluateExprAsBool(Cond); 824 Builder.CreateCondBr(CondV, TrueBlock, FalseBlock); 825 } 826 827 /// ErrorUnsupported - Print out an error that codegen doesn't support the 828 /// specified stmt yet. 829 void CodeGenFunction::ErrorUnsupported(const Stmt *S, const char *Type, 830 bool OmitOnError) { 831 CGM.ErrorUnsupported(S, Type, OmitOnError); 832 } 833 834 /// emitNonZeroVLAInit - Emit the "zero" initialization of a 835 /// variable-length array whose elements have a non-zero bit-pattern. 836 /// 837 /// \param baseType the inner-most element type of the array 838 /// \param src - a char* pointing to the bit-pattern for a single 839 /// base element of the array 840 /// \param sizeInChars - the total size of the VLA, in chars 841 static void emitNonZeroVLAInit(CodeGenFunction &CGF, QualType baseType, 842 llvm::Value *dest, llvm::Value *src, 843 llvm::Value *sizeInChars) { 844 std::pair<CharUnits,CharUnits> baseSizeAndAlign 845 = CGF.getContext().getTypeInfoInChars(baseType); 846 847 CGBuilderTy &Builder = CGF.Builder; 848 849 llvm::Value *baseSizeInChars 850 = llvm::ConstantInt::get(CGF.IntPtrTy, baseSizeAndAlign.first.getQuantity()); 851 852 llvm::Type *i8p = Builder.getInt8PtrTy(); 853 854 llvm::Value *begin = Builder.CreateBitCast(dest, i8p, "vla.begin"); 855 llvm::Value *end = Builder.CreateInBoundsGEP(dest, sizeInChars, "vla.end"); 856 857 llvm::BasicBlock *originBB = CGF.Builder.GetInsertBlock(); 858 llvm::BasicBlock *loopBB = CGF.createBasicBlock("vla-init.loop"); 859 llvm::BasicBlock *contBB = CGF.createBasicBlock("vla-init.cont"); 860 861 // Make a loop over the VLA. C99 guarantees that the VLA element 862 // count must be nonzero. 863 CGF.EmitBlock(loopBB); 864 865 llvm::PHINode *cur = Builder.CreatePHI(i8p, 2, "vla.cur"); 866 cur->addIncoming(begin, originBB); 867 868 // memcpy the individual element bit-pattern. 869 Builder.CreateMemCpy(cur, src, baseSizeInChars, 870 baseSizeAndAlign.second.getQuantity(), 871 /*volatile*/ false); 872 873 // Go to the next element. 874 llvm::Value *next = Builder.CreateConstInBoundsGEP1_32(cur, 1, "vla.next"); 875 876 // Leave if that's the end of the VLA. 877 llvm::Value *done = Builder.CreateICmpEQ(next, end, "vla-init.isdone"); 878 Builder.CreateCondBr(done, contBB, loopBB); 879 cur->addIncoming(next, loopBB); 880 881 CGF.EmitBlock(contBB); 882 } 883 884 void 885 CodeGenFunction::EmitNullInitialization(llvm::Value *DestPtr, QualType Ty) { 886 // Ignore empty classes in C++. 887 if (getLangOpts().CPlusPlus) { 888 if (const RecordType *RT = Ty->getAs<RecordType>()) { 889 if (cast<CXXRecordDecl>(RT->getDecl())->isEmpty()) 890 return; 891 } 892 } 893 894 // Cast the dest ptr to the appropriate i8 pointer type. 895 unsigned DestAS = 896 cast<llvm::PointerType>(DestPtr->getType())->getAddressSpace(); 897 llvm::Type *BP = Builder.getInt8PtrTy(DestAS); 898 if (DestPtr->getType() != BP) 899 DestPtr = Builder.CreateBitCast(DestPtr, BP); 900 901 // Get size and alignment info for this aggregate. 902 std::pair<CharUnits, CharUnits> TypeInfo = 903 getContext().getTypeInfoInChars(Ty); 904 CharUnits Size = TypeInfo.first; 905 CharUnits Align = TypeInfo.second; 906 907 llvm::Value *SizeVal; 908 const VariableArrayType *vla; 909 910 // Don't bother emitting a zero-byte memset. 911 if (Size.isZero()) { 912 // But note that getTypeInfo returns 0 for a VLA. 913 if (const VariableArrayType *vlaType = 914 dyn_cast_or_null<VariableArrayType>( 915 getContext().getAsArrayType(Ty))) { 916 QualType eltType; 917 llvm::Value *numElts; 918 llvm::tie(numElts, eltType) = getVLASize(vlaType); 919 920 SizeVal = numElts; 921 CharUnits eltSize = getContext().getTypeSizeInChars(eltType); 922 if (!eltSize.isOne()) 923 SizeVal = Builder.CreateNUWMul(SizeVal, CGM.getSize(eltSize)); 924 vla = vlaType; 925 } else { 926 return; 927 } 928 } else { 929 SizeVal = CGM.getSize(Size); 930 vla = 0; 931 } 932 933 // If the type contains a pointer to data member we can't memset it to zero. 934 // Instead, create a null constant and copy it to the destination. 935 // TODO: there are other patterns besides zero that we can usefully memset, 936 // like -1, which happens to be the pattern used by member-pointers. 937 if (!CGM.getTypes().isZeroInitializable(Ty)) { 938 // For a VLA, emit a single element, then splat that over the VLA. 939 if (vla) Ty = getContext().getBaseElementType(vla); 940 941 llvm::Constant *NullConstant = CGM.EmitNullConstant(Ty); 942 943 llvm::GlobalVariable *NullVariable = 944 new llvm::GlobalVariable(CGM.getModule(), NullConstant->getType(), 945 /*isConstant=*/true, 946 llvm::GlobalVariable::PrivateLinkage, 947 NullConstant, Twine()); 948 llvm::Value *SrcPtr = 949 Builder.CreateBitCast(NullVariable, Builder.getInt8PtrTy()); 950 951 if (vla) return emitNonZeroVLAInit(*this, Ty, DestPtr, SrcPtr, SizeVal); 952 953 // Get and call the appropriate llvm.memcpy overload. 954 Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, Align.getQuantity(), false); 955 return; 956 } 957 958 // Otherwise, just memset the whole thing to zero. This is legal 959 // because in LLVM, all default initializers (other than the ones we just 960 // handled above) are guaranteed to have a bit pattern of all zeros. 961 Builder.CreateMemSet(DestPtr, Builder.getInt8(0), SizeVal, 962 Align.getQuantity(), false); 963 } 964 965 llvm::BlockAddress *CodeGenFunction::GetAddrOfLabel(const LabelDecl *L) { 966 // Make sure that there is a block for the indirect goto. 967 if (IndirectBranch == 0) 968 GetIndirectGotoBlock(); 969 970 llvm::BasicBlock *BB = getJumpDestForLabel(L).getBlock(); 971 972 // Make sure the indirect branch includes all of the address-taken blocks. 973 IndirectBranch->addDestination(BB); 974 return llvm::BlockAddress::get(CurFn, BB); 975 } 976 977 llvm::BasicBlock *CodeGenFunction::GetIndirectGotoBlock() { 978 // If we already made the indirect branch for indirect goto, return its block. 979 if (IndirectBranch) return IndirectBranch->getParent(); 980 981 CGBuilderTy TmpBuilder(createBasicBlock("indirectgoto")); 982 983 // Create the PHI node that indirect gotos will add entries to. 984 llvm::Value *DestVal = TmpBuilder.CreatePHI(Int8PtrTy, 0, 985 "indirect.goto.dest"); 986 987 // Create the indirect branch instruction. 988 IndirectBranch = TmpBuilder.CreateIndirectBr(DestVal); 989 return IndirectBranch->getParent(); 990 } 991 992 /// Computes the length of an array in elements, as well as the base 993 /// element type and a properly-typed first element pointer. 994 llvm::Value *CodeGenFunction::emitArrayLength(const ArrayType *origArrayType, 995 QualType &baseType, 996 llvm::Value *&addr) { 997 const ArrayType *arrayType = origArrayType; 998 999 // If it's a VLA, we have to load the stored size. Note that 1000 // this is the size of the VLA in bytes, not its size in elements. 1001 llvm::Value *numVLAElements = 0; 1002 if (isa<VariableArrayType>(arrayType)) { 1003 numVLAElements = getVLASize(cast<VariableArrayType>(arrayType)).first; 1004 1005 // Walk into all VLAs. This doesn't require changes to addr, 1006 // which has type T* where T is the first non-VLA element type. 1007 do { 1008 QualType elementType = arrayType->getElementType(); 1009 arrayType = getContext().getAsArrayType(elementType); 1010 1011 // If we only have VLA components, 'addr' requires no adjustment. 1012 if (!arrayType) { 1013 baseType = elementType; 1014 return numVLAElements; 1015 } 1016 } while (isa<VariableArrayType>(arrayType)); 1017 1018 // We get out here only if we find a constant array type 1019 // inside the VLA. 1020 } 1021 1022 // We have some number of constant-length arrays, so addr should 1023 // have LLVM type [M x [N x [...]]]*. Build a GEP that walks 1024 // down to the first element of addr. 1025 SmallVector<llvm::Value*, 8> gepIndices; 1026 1027 // GEP down to the array type. 1028 llvm::ConstantInt *zero = Builder.getInt32(0); 1029 gepIndices.push_back(zero); 1030 1031 uint64_t countFromCLAs = 1; 1032 QualType eltType; 1033 1034 llvm::ArrayType *llvmArrayType = 1035 dyn_cast<llvm::ArrayType>( 1036 cast<llvm::PointerType>(addr->getType())->getElementType()); 1037 while (llvmArrayType) { 1038 assert(isa<ConstantArrayType>(arrayType)); 1039 assert(cast<ConstantArrayType>(arrayType)->getSize().getZExtValue() 1040 == llvmArrayType->getNumElements()); 1041 1042 gepIndices.push_back(zero); 1043 countFromCLAs *= llvmArrayType->getNumElements(); 1044 eltType = arrayType->getElementType(); 1045 1046 llvmArrayType = 1047 dyn_cast<llvm::ArrayType>(llvmArrayType->getElementType()); 1048 arrayType = getContext().getAsArrayType(arrayType->getElementType()); 1049 assert((!llvmArrayType || arrayType) && 1050 "LLVM and Clang types are out-of-synch"); 1051 } 1052 1053 if (arrayType) { 1054 // From this point onwards, the Clang array type has been emitted 1055 // as some other type (probably a packed struct). Compute the array 1056 // size, and just emit the 'begin' expression as a bitcast. 1057 while (arrayType) { 1058 countFromCLAs *= 1059 cast<ConstantArrayType>(arrayType)->getSize().getZExtValue(); 1060 eltType = arrayType->getElementType(); 1061 arrayType = getContext().getAsArrayType(eltType); 1062 } 1063 1064 unsigned AddressSpace = addr->getType()->getPointerAddressSpace(); 1065 llvm::Type *BaseType = ConvertType(eltType)->getPointerTo(AddressSpace); 1066 addr = Builder.CreateBitCast(addr, BaseType, "array.begin"); 1067 } else { 1068 // Create the actual GEP. 1069 addr = Builder.CreateInBoundsGEP(addr, gepIndices, "array.begin"); 1070 } 1071 1072 baseType = eltType; 1073 1074 llvm::Value *numElements 1075 = llvm::ConstantInt::get(SizeTy, countFromCLAs); 1076 1077 // If we had any VLA dimensions, factor them in. 1078 if (numVLAElements) 1079 numElements = Builder.CreateNUWMul(numVLAElements, numElements); 1080 1081 return numElements; 1082 } 1083 1084 std::pair<llvm::Value*, QualType> 1085 CodeGenFunction::getVLASize(QualType type) { 1086 const VariableArrayType *vla = getContext().getAsVariableArrayType(type); 1087 assert(vla && "type was not a variable array type!"); 1088 return getVLASize(vla); 1089 } 1090 1091 std::pair<llvm::Value*, QualType> 1092 CodeGenFunction::getVLASize(const VariableArrayType *type) { 1093 // The number of elements so far; always size_t. 1094 llvm::Value *numElements = 0; 1095 1096 QualType elementType; 1097 do { 1098 elementType = type->getElementType(); 1099 llvm::Value *vlaSize = VLASizeMap[type->getSizeExpr()]; 1100 assert(vlaSize && "no size for VLA!"); 1101 assert(vlaSize->getType() == SizeTy); 1102 1103 if (!numElements) { 1104 numElements = vlaSize; 1105 } else { 1106 // It's undefined behavior if this wraps around, so mark it that way. 1107 // FIXME: Teach -fcatch-undefined-behavior to trap this. 1108 numElements = Builder.CreateNUWMul(numElements, vlaSize); 1109 } 1110 } while ((type = getContext().getAsVariableArrayType(elementType))); 1111 1112 return std::pair<llvm::Value*,QualType>(numElements, elementType); 1113 } 1114 1115 void CodeGenFunction::EmitVariablyModifiedType(QualType type) { 1116 assert(type->isVariablyModifiedType() && 1117 "Must pass variably modified type to EmitVLASizes!"); 1118 1119 EnsureInsertPoint(); 1120 1121 // We're going to walk down into the type and look for VLA 1122 // expressions. 1123 do { 1124 assert(type->isVariablyModifiedType()); 1125 1126 const Type *ty = type.getTypePtr(); 1127 switch (ty->getTypeClass()) { 1128 1129 #define TYPE(Class, Base) 1130 #define ABSTRACT_TYPE(Class, Base) 1131 #define NON_CANONICAL_TYPE(Class, Base) 1132 #define DEPENDENT_TYPE(Class, Base) case Type::Class: 1133 #define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) 1134 #include "clang/AST/TypeNodes.def" 1135 llvm_unreachable("unexpected dependent type!"); 1136 1137 // These types are never variably-modified. 1138 case Type::Builtin: 1139 case Type::Complex: 1140 case Type::Vector: 1141 case Type::ExtVector: 1142 case Type::Record: 1143 case Type::Enum: 1144 case Type::Elaborated: 1145 case Type::TemplateSpecialization: 1146 case Type::ObjCObject: 1147 case Type::ObjCInterface: 1148 case Type::ObjCObjectPointer: 1149 llvm_unreachable("type class is never variably-modified!"); 1150 1151 case Type::Pointer: 1152 type = cast<PointerType>(ty)->getPointeeType(); 1153 break; 1154 1155 case Type::BlockPointer: 1156 type = cast<BlockPointerType>(ty)->getPointeeType(); 1157 break; 1158 1159 case Type::LValueReference: 1160 case Type::RValueReference: 1161 type = cast<ReferenceType>(ty)->getPointeeType(); 1162 break; 1163 1164 case Type::MemberPointer: 1165 type = cast<MemberPointerType>(ty)->getPointeeType(); 1166 break; 1167 1168 case Type::ConstantArray: 1169 case Type::IncompleteArray: 1170 // Losing element qualification here is fine. 1171 type = cast<ArrayType>(ty)->getElementType(); 1172 break; 1173 1174 case Type::VariableArray: { 1175 // Losing element qualification here is fine. 1176 const VariableArrayType *vat = cast<VariableArrayType>(ty); 1177 1178 // Unknown size indication requires no size computation. 1179 // Otherwise, evaluate and record it. 1180 if (const Expr *size = vat->getSizeExpr()) { 1181 // It's possible that we might have emitted this already, 1182 // e.g. with a typedef and a pointer to it. 1183 llvm::Value *&entry = VLASizeMap[size]; 1184 if (!entry) { 1185 llvm::Value *Size = EmitScalarExpr(size); 1186 1187 // C11 6.7.6.2p5: 1188 // If the size is an expression that is not an integer constant 1189 // expression [...] each time it is evaluated it shall have a value 1190 // greater than zero. 1191 if (SanOpts->VLABound && 1192 size->getType()->isSignedIntegerType()) { 1193 llvm::Value *Zero = llvm::Constant::getNullValue(Size->getType()); 1194 llvm::Constant *StaticArgs[] = { 1195 EmitCheckSourceLocation(size->getLocStart()), 1196 EmitCheckTypeDescriptor(size->getType()) 1197 }; 1198 EmitCheck(Builder.CreateICmpSGT(Size, Zero), 1199 "vla_bound_not_positive", StaticArgs, Size, 1200 CRK_Recoverable); 1201 } 1202 1203 // Always zexting here would be wrong if it weren't 1204 // undefined behavior to have a negative bound. 1205 entry = Builder.CreateIntCast(Size, SizeTy, /*signed*/ false); 1206 } 1207 } 1208 type = vat->getElementType(); 1209 break; 1210 } 1211 1212 case Type::FunctionProto: 1213 case Type::FunctionNoProto: 1214 type = cast<FunctionType>(ty)->getResultType(); 1215 break; 1216 1217 case Type::Paren: 1218 case Type::TypeOf: 1219 case Type::UnaryTransform: 1220 case Type::Attributed: 1221 case Type::SubstTemplateTypeParm: 1222 // Keep walking after single level desugaring. 1223 type = type.getSingleStepDesugaredType(getContext()); 1224 break; 1225 1226 case Type::Typedef: 1227 case Type::Decltype: 1228 case Type::Auto: 1229 // Stop walking: nothing to do. 1230 return; 1231 1232 case Type::TypeOfExpr: 1233 // Stop walking: emit typeof expression. 1234 EmitIgnoredExpr(cast<TypeOfExprType>(ty)->getUnderlyingExpr()); 1235 return; 1236 1237 case Type::Atomic: 1238 type = cast<AtomicType>(ty)->getValueType(); 1239 break; 1240 } 1241 } while (type->isVariablyModifiedType()); 1242 } 1243 1244 llvm::Value* CodeGenFunction::EmitVAListRef(const Expr* E) { 1245 if (getContext().getBuiltinVaListType()->isArrayType()) 1246 return EmitScalarExpr(E); 1247 return EmitLValue(E).getAddress(); 1248 } 1249 1250 void CodeGenFunction::EmitDeclRefExprDbgValue(const DeclRefExpr *E, 1251 llvm::Constant *Init) { 1252 assert (Init && "Invalid DeclRefExpr initializer!"); 1253 if (CGDebugInfo *Dbg = getDebugInfo()) 1254 if (CGM.getCodeGenOpts().getDebugInfo() >= CodeGenOptions::LimitedDebugInfo) 1255 Dbg->EmitGlobalVariable(E->getDecl(), Init); 1256 } 1257 1258 CodeGenFunction::PeepholeProtection 1259 CodeGenFunction::protectFromPeepholes(RValue rvalue) { 1260 // At the moment, the only aggressive peephole we do in IR gen 1261 // is trunc(zext) folding, but if we add more, we can easily 1262 // extend this protection. 1263 1264 if (!rvalue.isScalar()) return PeepholeProtection(); 1265 llvm::Value *value = rvalue.getScalarVal(); 1266 if (!isa<llvm::ZExtInst>(value)) return PeepholeProtection(); 1267 1268 // Just make an extra bitcast. 1269 assert(HaveInsertPoint()); 1270 llvm::Instruction *inst = new llvm::BitCastInst(value, value->getType(), "", 1271 Builder.GetInsertBlock()); 1272 1273 PeepholeProtection protection; 1274 protection.Inst = inst; 1275 return protection; 1276 } 1277 1278 void CodeGenFunction::unprotectFromPeepholes(PeepholeProtection protection) { 1279 if (!protection.Inst) return; 1280 1281 // In theory, we could try to duplicate the peepholes now, but whatever. 1282 protection.Inst->eraseFromParent(); 1283 } 1284 1285 llvm::Value *CodeGenFunction::EmitAnnotationCall(llvm::Value *AnnotationFn, 1286 llvm::Value *AnnotatedVal, 1287 StringRef AnnotationStr, 1288 SourceLocation Location) { 1289 llvm::Value *Args[4] = { 1290 AnnotatedVal, 1291 Builder.CreateBitCast(CGM.EmitAnnotationString(AnnotationStr), Int8PtrTy), 1292 Builder.CreateBitCast(CGM.EmitAnnotationUnit(Location), Int8PtrTy), 1293 CGM.EmitAnnotationLineNo(Location) 1294 }; 1295 return Builder.CreateCall(AnnotationFn, Args); 1296 } 1297 1298 void CodeGenFunction::EmitVarAnnotations(const VarDecl *D, llvm::Value *V) { 1299 assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute"); 1300 // FIXME We create a new bitcast for every annotation because that's what 1301 // llvm-gcc was doing. 1302 for (specific_attr_iterator<AnnotateAttr> 1303 ai = D->specific_attr_begin<AnnotateAttr>(), 1304 ae = D->specific_attr_end<AnnotateAttr>(); ai != ae; ++ai) 1305 EmitAnnotationCall(CGM.getIntrinsic(llvm::Intrinsic::var_annotation), 1306 Builder.CreateBitCast(V, CGM.Int8PtrTy, V->getName()), 1307 (*ai)->getAnnotation(), D->getLocation()); 1308 } 1309 1310 llvm::Value *CodeGenFunction::EmitFieldAnnotations(const FieldDecl *D, 1311 llvm::Value *V) { 1312 assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute"); 1313 llvm::Type *VTy = V->getType(); 1314 llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::ptr_annotation, 1315 CGM.Int8PtrTy); 1316 1317 for (specific_attr_iterator<AnnotateAttr> 1318 ai = D->specific_attr_begin<AnnotateAttr>(), 1319 ae = D->specific_attr_end<AnnotateAttr>(); ai != ae; ++ai) { 1320 // FIXME Always emit the cast inst so we can differentiate between 1321 // annotation on the first field of a struct and annotation on the struct 1322 // itself. 1323 if (VTy != CGM.Int8PtrTy) 1324 V = Builder.Insert(new llvm::BitCastInst(V, CGM.Int8PtrTy)); 1325 V = EmitAnnotationCall(F, V, (*ai)->getAnnotation(), D->getLocation()); 1326 V = Builder.CreateBitCast(V, VTy); 1327 } 1328 1329 return V; 1330 } 1331