CodeGenFunction.cpp revision 243830
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 "CodeGenModule.h" 16#include "CGCUDARuntime.h" 17#include "CGCXXABI.h" 18#include "CGDebugInfo.h" 19#include "clang/Basic/TargetInfo.h" 20#include "clang/AST/ASTContext.h" 21#include "clang/AST/Decl.h" 22#include "clang/AST/DeclCXX.h" 23#include "clang/AST/StmtCXX.h" 24#include "clang/Frontend/CodeGenOptions.h" 25#include "llvm/Intrinsics.h" 26#include "llvm/MDBuilder.h" 27#include "llvm/DataLayout.h" 28using namespace clang; 29using namespace CodeGen; 30 31CodeGenFunction::CodeGenFunction(CodeGenModule &cgm, bool suppressNewContext) 32 : CodeGenTypeCache(cgm), CGM(cgm), 33 Target(CGM.getContext().getTargetInfo()), 34 Builder(cgm.getModule().getContext()), 35 SanitizePerformTypeCheck(CGM.getLangOpts().SanitizeNull | 36 CGM.getLangOpts().SanitizeAlignment | 37 CGM.getLangOpts().SanitizeObjectSize | 38 CGM.getLangOpts().SanitizeVptr), 39 AutoreleaseResult(false), BlockInfo(0), BlockPointer(0), 40 LambdaThisCaptureField(0), NormalCleanupDest(0), NextCleanupDestIndex(1), 41 FirstBlockInfo(0), EHResumeBlock(0), ExceptionSlot(0), EHSelectorSlot(0), 42 DebugInfo(0), DisableDebugInfo(false), DidCallStackSave(false), 43 IndirectBranch(0), SwitchInsn(0), CaseRangeBlock(0), UnreachableBlock(0), 44 CXXABIThisDecl(0), CXXABIThisValue(0), CXXThisValue(0), CXXVTTDecl(0), 45 CXXVTTValue(0), OutermostConditional(0), TerminateLandingPad(0), 46 TerminateHandler(0), TrapBB(0) { 47 if (!suppressNewContext) 48 CGM.getCXXABI().getMangleContext().startNewFunction(); 49} 50 51CodeGenFunction::~CodeGenFunction() { 52 // If there are any unclaimed block infos, go ahead and destroy them 53 // now. This can happen if IR-gen gets clever and skips evaluating 54 // something. 55 if (FirstBlockInfo) 56 destroyBlockInfos(FirstBlockInfo); 57} 58 59 60llvm::Type *CodeGenFunction::ConvertTypeForMem(QualType T) { 61 return CGM.getTypes().ConvertTypeForMem(T); 62} 63 64llvm::Type *CodeGenFunction::ConvertType(QualType T) { 65 return CGM.getTypes().ConvertType(T); 66} 67 68bool CodeGenFunction::hasAggregateLLVMType(QualType type) { 69 switch (type.getCanonicalType()->getTypeClass()) { 70#define TYPE(name, parent) 71#define ABSTRACT_TYPE(name, parent) 72#define NON_CANONICAL_TYPE(name, parent) case Type::name: 73#define DEPENDENT_TYPE(name, parent) case Type::name: 74#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(name, parent) case Type::name: 75#include "clang/AST/TypeNodes.def" 76 llvm_unreachable("non-canonical or dependent type in IR-generation"); 77 78 case Type::Builtin: 79 case Type::Pointer: 80 case Type::BlockPointer: 81 case Type::LValueReference: 82 case Type::RValueReference: 83 case Type::MemberPointer: 84 case Type::Vector: 85 case Type::ExtVector: 86 case Type::FunctionProto: 87 case Type::FunctionNoProto: 88 case Type::Enum: 89 case Type::ObjCObjectPointer: 90 return false; 91 92 // Complexes, arrays, records, and Objective-C objects. 93 case Type::Complex: 94 case Type::ConstantArray: 95 case Type::IncompleteArray: 96 case Type::VariableArray: 97 case Type::Record: 98 case Type::ObjCObject: 99 case Type::ObjCInterface: 100 return true; 101 102 // In IRGen, atomic types are just the underlying type 103 case Type::Atomic: 104 return hasAggregateLLVMType(type->getAs<AtomicType>()->getValueType()); 105 } 106 llvm_unreachable("unknown type kind!"); 107} 108 109void CodeGenFunction::EmitReturnBlock() { 110 // For cleanliness, we try to avoid emitting the return block for 111 // simple cases. 112 llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); 113 114 if (CurBB) { 115 assert(!CurBB->getTerminator() && "Unexpected terminated block."); 116 117 // We have a valid insert point, reuse it if it is empty or there are no 118 // explicit jumps to the return block. 119 if (CurBB->empty() || ReturnBlock.getBlock()->use_empty()) { 120 ReturnBlock.getBlock()->replaceAllUsesWith(CurBB); 121 delete ReturnBlock.getBlock(); 122 } else 123 EmitBlock(ReturnBlock.getBlock()); 124 return; 125 } 126 127 // Otherwise, if the return block is the target of a single direct 128 // branch then we can just put the code in that block instead. This 129 // cleans up functions which started with a unified return block. 130 if (ReturnBlock.getBlock()->hasOneUse()) { 131 llvm::BranchInst *BI = 132 dyn_cast<llvm::BranchInst>(*ReturnBlock.getBlock()->use_begin()); 133 if (BI && BI->isUnconditional() && 134 BI->getSuccessor(0) == ReturnBlock.getBlock()) { 135 // Reset insertion point, including debug location, and delete the branch. 136 Builder.SetCurrentDebugLocation(BI->getDebugLoc()); 137 Builder.SetInsertPoint(BI->getParent()); 138 BI->eraseFromParent(); 139 delete ReturnBlock.getBlock(); 140 return; 141 } 142 } 143 144 // FIXME: We are at an unreachable point, there is no reason to emit the block 145 // unless it has uses. However, we still need a place to put the debug 146 // region.end for now. 147 148 EmitBlock(ReturnBlock.getBlock()); 149} 150 151static void EmitIfUsed(CodeGenFunction &CGF, llvm::BasicBlock *BB) { 152 if (!BB) return; 153 if (!BB->use_empty()) 154 return CGF.CurFn->getBasicBlockList().push_back(BB); 155 delete BB; 156} 157 158void CodeGenFunction::FinishFunction(SourceLocation EndLoc) { 159 assert(BreakContinueStack.empty() && 160 "mismatched push/pop in break/continue stack!"); 161 162 // Pop any cleanups that might have been associated with the 163 // parameters. Do this in whatever block we're currently in; it's 164 // important to do this before we enter the return block or return 165 // edges will be *really* confused. 166 if (EHStack.stable_begin() != PrologueCleanupDepth) 167 PopCleanupBlocks(PrologueCleanupDepth); 168 169 // Emit function epilog (to return). 170 EmitReturnBlock(); 171 172 if (ShouldInstrumentFunction()) 173 EmitFunctionInstrumentation("__cyg_profile_func_exit"); 174 175 // Emit debug descriptor for function end. 176 if (CGDebugInfo *DI = getDebugInfo()) { 177 DI->setLocation(EndLoc); 178 DI->EmitFunctionEnd(Builder); 179 } 180 181 EmitFunctionEpilog(*CurFnInfo); 182 EmitEndEHSpec(CurCodeDecl); 183 184 assert(EHStack.empty() && 185 "did not remove all scopes from cleanup stack!"); 186 187 // If someone did an indirect goto, emit the indirect goto block at the end of 188 // the function. 189 if (IndirectBranch) { 190 EmitBlock(IndirectBranch->getParent()); 191 Builder.ClearInsertionPoint(); 192 } 193 194 // Remove the AllocaInsertPt instruction, which is just a convenience for us. 195 llvm::Instruction *Ptr = AllocaInsertPt; 196 AllocaInsertPt = 0; 197 Ptr->eraseFromParent(); 198 199 // If someone took the address of a label but never did an indirect goto, we 200 // made a zero entry PHI node, which is illegal, zap it now. 201 if (IndirectBranch) { 202 llvm::PHINode *PN = cast<llvm::PHINode>(IndirectBranch->getAddress()); 203 if (PN->getNumIncomingValues() == 0) { 204 PN->replaceAllUsesWith(llvm::UndefValue::get(PN->getType())); 205 PN->eraseFromParent(); 206 } 207 } 208 209 EmitIfUsed(*this, EHResumeBlock); 210 EmitIfUsed(*this, TerminateLandingPad); 211 EmitIfUsed(*this, TerminateHandler); 212 EmitIfUsed(*this, UnreachableBlock); 213 214 if (CGM.getCodeGenOpts().EmitDeclMetadata) 215 EmitDeclMetadata(); 216} 217 218/// ShouldInstrumentFunction - Return true if the current function should be 219/// instrumented with __cyg_profile_func_* calls 220bool CodeGenFunction::ShouldInstrumentFunction() { 221 if (!CGM.getCodeGenOpts().InstrumentFunctions) 222 return false; 223 if (!CurFuncDecl || CurFuncDecl->hasAttr<NoInstrumentFunctionAttr>()) 224 return false; 225 return true; 226} 227 228/// EmitFunctionInstrumentation - Emit LLVM code to call the specified 229/// instrumentation function with the current function and the call site, if 230/// function instrumentation is enabled. 231void CodeGenFunction::EmitFunctionInstrumentation(const char *Fn) { 232 // void __cyg_profile_func_{enter,exit} (void *this_fn, void *call_site); 233 llvm::PointerType *PointerTy = Int8PtrTy; 234 llvm::Type *ProfileFuncArgs[] = { PointerTy, PointerTy }; 235 llvm::FunctionType *FunctionTy = 236 llvm::FunctionType::get(VoidTy, ProfileFuncArgs, false); 237 238 llvm::Constant *F = CGM.CreateRuntimeFunction(FunctionTy, Fn); 239 llvm::CallInst *CallSite = Builder.CreateCall( 240 CGM.getIntrinsic(llvm::Intrinsic::returnaddress), 241 llvm::ConstantInt::get(Int32Ty, 0), 242 "callsite"); 243 244 Builder.CreateCall2(F, 245 llvm::ConstantExpr::getBitCast(CurFn, PointerTy), 246 CallSite); 247} 248 249void CodeGenFunction::EmitMCountInstrumentation() { 250 llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false); 251 252 llvm::Constant *MCountFn = CGM.CreateRuntimeFunction(FTy, 253 Target.getMCountName()); 254 Builder.CreateCall(MCountFn); 255} 256 257// OpenCL v1.2 s5.6.4.6 allows the compiler to store kernel argument 258// information in the program executable. The argument information stored 259// includes the argument name, its type, the address and access qualifiers used. 260// FIXME: Add type, address, and access qualifiers. 261static void GenOpenCLArgMetadata(const FunctionDecl *FD, llvm::Function *Fn, 262 CodeGenModule &CGM,llvm::LLVMContext &Context, 263 llvm::SmallVector <llvm::Value*, 5> &kernelMDArgs) { 264 265 // Create MDNodes that represents the kernel arg metadata. 266 // Each MDNode is a list in the form of "key", N number of values which is 267 // the same number of values as their are kernel arguments. 268 269 // MDNode for the kernel argument names. 270 SmallVector<llvm::Value*, 8> argNames; 271 argNames.push_back(llvm::MDString::get(Context, "kernel_arg_name")); 272 273 for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i) { 274 const ParmVarDecl *parm = FD->getParamDecl(i); 275 276 // Get argument name. 277 argNames.push_back(llvm::MDString::get(Context, parm->getName())); 278 279 } 280 // Add MDNode to the list of all metadata. 281 kernelMDArgs.push_back(llvm::MDNode::get(Context, argNames)); 282} 283 284void CodeGenFunction::EmitOpenCLKernelMetadata(const FunctionDecl *FD, 285 llvm::Function *Fn) 286{ 287 if (!FD->hasAttr<OpenCLKernelAttr>()) 288 return; 289 290 llvm::LLVMContext &Context = getLLVMContext(); 291 292 llvm::SmallVector <llvm::Value*, 5> kernelMDArgs; 293 kernelMDArgs.push_back(Fn); 294 295 if (CGM.getCodeGenOpts().EmitOpenCLArgMetadata) 296 GenOpenCLArgMetadata(FD, Fn, CGM, Context, kernelMDArgs); 297 298 if (FD->hasAttr<WorkGroupSizeHintAttr>()) { 299 llvm::SmallVector <llvm::Value*, 5> attrMDArgs; 300 attrMDArgs.push_back(llvm::MDString::get(Context, "work_group_size_hint")); 301 WorkGroupSizeHintAttr *attr = FD->getAttr<WorkGroupSizeHintAttr>(); 302 llvm::Type *iTy = llvm::IntegerType::get(Context, 32); 303 attrMDArgs.push_back(llvm::ConstantInt::get(iTy, 304 llvm::APInt(32, (uint64_t)attr->getXDim()))); 305 attrMDArgs.push_back(llvm::ConstantInt::get(iTy, 306 llvm::APInt(32, (uint64_t)attr->getYDim()))); 307 attrMDArgs.push_back(llvm::ConstantInt::get(iTy, 308 llvm::APInt(32, (uint64_t)attr->getZDim()))); 309 kernelMDArgs.push_back(llvm::MDNode::get(Context, attrMDArgs)); 310 } 311 312 if (FD->hasAttr<ReqdWorkGroupSizeAttr>()) { 313 llvm::SmallVector <llvm::Value*, 5> attrMDArgs; 314 attrMDArgs.push_back(llvm::MDString::get(Context, "reqd_work_group_size")); 315 ReqdWorkGroupSizeAttr *attr = FD->getAttr<ReqdWorkGroupSizeAttr>(); 316 llvm::Type *iTy = llvm::IntegerType::get(Context, 32); 317 attrMDArgs.push_back(llvm::ConstantInt::get(iTy, 318 llvm::APInt(32, (uint64_t)attr->getXDim()))); 319 attrMDArgs.push_back(llvm::ConstantInt::get(iTy, 320 llvm::APInt(32, (uint64_t)attr->getYDim()))); 321 attrMDArgs.push_back(llvm::ConstantInt::get(iTy, 322 llvm::APInt(32, (uint64_t)attr->getZDim()))); 323 kernelMDArgs.push_back(llvm::MDNode::get(Context, attrMDArgs)); 324 } 325 326 llvm::MDNode *kernelMDNode = llvm::MDNode::get(Context, kernelMDArgs); 327 llvm::NamedMDNode *OpenCLKernelMetadata = 328 CGM.getModule().getOrInsertNamedMetadata("opencl.kernels"); 329 OpenCLKernelMetadata->addOperand(kernelMDNode); 330} 331 332void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy, 333 llvm::Function *Fn, 334 const CGFunctionInfo &FnInfo, 335 const FunctionArgList &Args, 336 SourceLocation StartLoc) { 337 const Decl *D = GD.getDecl(); 338 339 DidCallStackSave = false; 340 CurCodeDecl = CurFuncDecl = D; 341 FnRetTy = RetTy; 342 CurFn = Fn; 343 CurFnInfo = &FnInfo; 344 assert(CurFn->isDeclaration() && "Function already has body?"); 345 346 // Pass inline keyword to optimizer if it appears explicitly on any 347 // declaration. 348 if (!CGM.getCodeGenOpts().NoInline) 349 if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) 350 for (FunctionDecl::redecl_iterator RI = FD->redecls_begin(), 351 RE = FD->redecls_end(); RI != RE; ++RI) 352 if (RI->isInlineSpecified()) { 353 Fn->addFnAttr(llvm::Attributes::InlineHint); 354 break; 355 } 356 357 if (getLangOpts().OpenCL) { 358 // Add metadata for a kernel function. 359 if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) 360 EmitOpenCLKernelMetadata(FD, Fn); 361 } 362 363 llvm::BasicBlock *EntryBB = createBasicBlock("entry", CurFn); 364 365 // Create a marker to make it easy to insert allocas into the entryblock 366 // later. Don't create this with the builder, because we don't want it 367 // folded. 368 llvm::Value *Undef = llvm::UndefValue::get(Int32Ty); 369 AllocaInsertPt = new llvm::BitCastInst(Undef, Int32Ty, "", EntryBB); 370 if (Builder.isNamePreserving()) 371 AllocaInsertPt->setName("allocapt"); 372 373 ReturnBlock = getJumpDestInCurrentScope("return"); 374 375 Builder.SetInsertPoint(EntryBB); 376 377 // Emit subprogram debug descriptor. 378 if (CGDebugInfo *DI = getDebugInfo()) { 379 unsigned NumArgs = 0; 380 QualType *ArgsArray = new QualType[Args.size()]; 381 for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end(); 382 i != e; ++i) { 383 ArgsArray[NumArgs++] = (*i)->getType(); 384 } 385 386 QualType FnType = 387 getContext().getFunctionType(RetTy, ArgsArray, NumArgs, 388 FunctionProtoType::ExtProtoInfo()); 389 390 delete[] ArgsArray; 391 392 DI->setLocation(StartLoc); 393 DI->EmitFunctionStart(GD, FnType, CurFn, Builder); 394 } 395 396 if (ShouldInstrumentFunction()) 397 EmitFunctionInstrumentation("__cyg_profile_func_enter"); 398 399 if (CGM.getCodeGenOpts().InstrumentForProfiling) 400 EmitMCountInstrumentation(); 401 402 if (RetTy->isVoidType()) { 403 // Void type; nothing to return. 404 ReturnValue = 0; 405 } else if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::Indirect && 406 hasAggregateLLVMType(CurFnInfo->getReturnType())) { 407 // Indirect aggregate return; emit returned value directly into sret slot. 408 // This reduces code size, and affects correctness in C++. 409 ReturnValue = CurFn->arg_begin(); 410 } else { 411 ReturnValue = CreateIRTemp(RetTy, "retval"); 412 413 // Tell the epilog emitter to autorelease the result. We do this 414 // now so that various specialized functions can suppress it 415 // during their IR-generation. 416 if (getLangOpts().ObjCAutoRefCount && 417 !CurFnInfo->isReturnsRetained() && 418 RetTy->isObjCRetainableType()) 419 AutoreleaseResult = true; 420 } 421 422 EmitStartEHSpec(CurCodeDecl); 423 424 PrologueCleanupDepth = EHStack.stable_begin(); 425 EmitFunctionProlog(*CurFnInfo, CurFn, Args); 426 427 if (D && isa<CXXMethodDecl>(D) && cast<CXXMethodDecl>(D)->isInstance()) { 428 CGM.getCXXABI().EmitInstanceFunctionProlog(*this); 429 const CXXMethodDecl *MD = cast<CXXMethodDecl>(D); 430 if (MD->getParent()->isLambda() && 431 MD->getOverloadedOperator() == OO_Call) { 432 // We're in a lambda; figure out the captures. 433 MD->getParent()->getCaptureFields(LambdaCaptureFields, 434 LambdaThisCaptureField); 435 if (LambdaThisCaptureField) { 436 // If this lambda captures this, load it. 437 QualType LambdaTagType = 438 getContext().getTagDeclType(LambdaThisCaptureField->getParent()); 439 LValue LambdaLV = MakeNaturalAlignAddrLValue(CXXABIThisValue, 440 LambdaTagType); 441 LValue ThisLValue = EmitLValueForField(LambdaLV, 442 LambdaThisCaptureField); 443 CXXThisValue = EmitLoadOfLValue(ThisLValue).getScalarVal(); 444 } 445 } else { 446 // Not in a lambda; just use 'this' from the method. 447 // FIXME: Should we generate a new load for each use of 'this'? The 448 // fast register allocator would be happier... 449 CXXThisValue = CXXABIThisValue; 450 } 451 } 452 453 // If any of the arguments have a variably modified type, make sure to 454 // emit the type size. 455 for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end(); 456 i != e; ++i) { 457 QualType Ty = (*i)->getType(); 458 459 if (Ty->isVariablyModifiedType()) 460 EmitVariablyModifiedType(Ty); 461 } 462 // Emit a location at the end of the prologue. 463 if (CGDebugInfo *DI = getDebugInfo()) 464 DI->EmitLocation(Builder, StartLoc); 465} 466 467void CodeGenFunction::EmitFunctionBody(FunctionArgList &Args) { 468 const FunctionDecl *FD = cast<FunctionDecl>(CurGD.getDecl()); 469 assert(FD->getBody()); 470 EmitStmt(FD->getBody()); 471} 472 473/// Tries to mark the given function nounwind based on the 474/// non-existence of any throwing calls within it. We believe this is 475/// lightweight enough to do at -O0. 476static void TryMarkNoThrow(llvm::Function *F) { 477 // LLVM treats 'nounwind' on a function as part of the type, so we 478 // can't do this on functions that can be overwritten. 479 if (F->mayBeOverridden()) return; 480 481 for (llvm::Function::iterator FI = F->begin(), FE = F->end(); FI != FE; ++FI) 482 for (llvm::BasicBlock::iterator 483 BI = FI->begin(), BE = FI->end(); BI != BE; ++BI) 484 if (llvm::CallInst *Call = dyn_cast<llvm::CallInst>(&*BI)) { 485 if (!Call->doesNotThrow()) 486 return; 487 } else if (isa<llvm::ResumeInst>(&*BI)) { 488 return; 489 } 490 F->setDoesNotThrow(); 491} 492 493void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn, 494 const CGFunctionInfo &FnInfo) { 495 const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); 496 497 // Check if we should generate debug info for this function. 498 if (!FD->hasAttr<NoDebugAttr>()) 499 maybeInitializeDebugInfo(); 500 501 FunctionArgList Args; 502 QualType ResTy = FD->getResultType(); 503 504 CurGD = GD; 505 if (isa<CXXMethodDecl>(FD) && cast<CXXMethodDecl>(FD)->isInstance()) 506 CGM.getCXXABI().BuildInstanceFunctionParams(*this, ResTy, Args); 507 508 for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i) 509 Args.push_back(FD->getParamDecl(i)); 510 511 SourceRange BodyRange; 512 if (Stmt *Body = FD->getBody()) BodyRange = Body->getSourceRange(); 513 514 // Emit the standard function prologue. 515 StartFunction(GD, ResTy, Fn, FnInfo, Args, BodyRange.getBegin()); 516 517 // Generate the body of the function. 518 if (isa<CXXDestructorDecl>(FD)) 519 EmitDestructorBody(Args); 520 else if (isa<CXXConstructorDecl>(FD)) 521 EmitConstructorBody(Args); 522 else if (getLangOpts().CUDA && 523 !CGM.getCodeGenOpts().CUDAIsDevice && 524 FD->hasAttr<CUDAGlobalAttr>()) 525 CGM.getCUDARuntime().EmitDeviceStubBody(*this, Args); 526 else if (isa<CXXConversionDecl>(FD) && 527 cast<CXXConversionDecl>(FD)->isLambdaToBlockPointerConversion()) { 528 // The lambda conversion to block pointer is special; the semantics can't be 529 // expressed in the AST, so IRGen needs to special-case it. 530 EmitLambdaToBlockPointerBody(Args); 531 } else if (isa<CXXMethodDecl>(FD) && 532 cast<CXXMethodDecl>(FD)->isLambdaStaticInvoker()) { 533 // The lambda "__invoke" function is special, because it forwards or 534 // clones the body of the function call operator (but is actually static). 535 EmitLambdaStaticInvokeFunction(cast<CXXMethodDecl>(FD)); 536 } 537 else 538 EmitFunctionBody(Args); 539 540 // C++11 [stmt.return]p2: 541 // Flowing off the end of a function [...] results in undefined behavior in 542 // a value-returning function. 543 // C11 6.9.1p12: 544 // If the '}' that terminates a function is reached, and the value of the 545 // function call is used by the caller, the behavior is undefined. 546 if (getLangOpts().CPlusPlus && !FD->hasImplicitReturnZero() && 547 !FD->getResultType()->isVoidType() && Builder.GetInsertBlock()) { 548 if (getLangOpts().SanitizeReturn) 549 EmitCheck(Builder.getFalse(), "missing_return", 550 EmitCheckSourceLocation(FD->getLocation()), 551 llvm::ArrayRef<llvm::Value*>()); 552 else if (CGM.getCodeGenOpts().OptimizationLevel == 0) 553 Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::trap)); 554 Builder.CreateUnreachable(); 555 Builder.ClearInsertionPoint(); 556 } 557 558 // Emit the standard function epilogue. 559 FinishFunction(BodyRange.getEnd()); 560 561 // If we haven't marked the function nothrow through other means, do 562 // a quick pass now to see if we can. 563 if (!CurFn->doesNotThrow()) 564 TryMarkNoThrow(CurFn); 565} 566 567/// ContainsLabel - Return true if the statement contains a label in it. If 568/// this statement is not executed normally, it not containing a label means 569/// that we can just remove the code. 570bool CodeGenFunction::ContainsLabel(const Stmt *S, bool IgnoreCaseStmts) { 571 // Null statement, not a label! 572 if (S == 0) return false; 573 574 // If this is a label, we have to emit the code, consider something like: 575 // if (0) { ... foo: bar(); } goto foo; 576 // 577 // TODO: If anyone cared, we could track __label__'s, since we know that you 578 // can't jump to one from outside their declared region. 579 if (isa<LabelStmt>(S)) 580 return true; 581 582 // If this is a case/default statement, and we haven't seen a switch, we have 583 // to emit the code. 584 if (isa<SwitchCase>(S) && !IgnoreCaseStmts) 585 return true; 586 587 // If this is a switch statement, we want to ignore cases below it. 588 if (isa<SwitchStmt>(S)) 589 IgnoreCaseStmts = true; 590 591 // Scan subexpressions for verboten labels. 592 for (Stmt::const_child_range I = S->children(); I; ++I) 593 if (ContainsLabel(*I, IgnoreCaseStmts)) 594 return true; 595 596 return false; 597} 598 599/// containsBreak - Return true if the statement contains a break out of it. 600/// If the statement (recursively) contains a switch or loop with a break 601/// inside of it, this is fine. 602bool CodeGenFunction::containsBreak(const Stmt *S) { 603 // Null statement, not a label! 604 if (S == 0) return false; 605 606 // If this is a switch or loop that defines its own break scope, then we can 607 // include it and anything inside of it. 608 if (isa<SwitchStmt>(S) || isa<WhileStmt>(S) || isa<DoStmt>(S) || 609 isa<ForStmt>(S)) 610 return false; 611 612 if (isa<BreakStmt>(S)) 613 return true; 614 615 // Scan subexpressions for verboten breaks. 616 for (Stmt::const_child_range I = S->children(); I; ++I) 617 if (containsBreak(*I)) 618 return true; 619 620 return false; 621} 622 623 624/// ConstantFoldsToSimpleInteger - If the specified expression does not fold 625/// to a constant, or if it does but contains a label, return false. If it 626/// constant folds return true and set the boolean result in Result. 627bool CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond, 628 bool &ResultBool) { 629 llvm::APSInt ResultInt; 630 if (!ConstantFoldsToSimpleInteger(Cond, ResultInt)) 631 return false; 632 633 ResultBool = ResultInt.getBoolValue(); 634 return true; 635} 636 637/// ConstantFoldsToSimpleInteger - If the specified expression does not fold 638/// to a constant, or if it does but contains a label, return false. If it 639/// constant folds return true and set the folded value. 640bool CodeGenFunction:: 641ConstantFoldsToSimpleInteger(const Expr *Cond, llvm::APSInt &ResultInt) { 642 // FIXME: Rename and handle conversion of other evaluatable things 643 // to bool. 644 llvm::APSInt Int; 645 if (!Cond->EvaluateAsInt(Int, getContext())) 646 return false; // Not foldable, not integer or not fully evaluatable. 647 648 if (CodeGenFunction::ContainsLabel(Cond)) 649 return false; // Contains a label. 650 651 ResultInt = Int; 652 return true; 653} 654 655 656 657/// EmitBranchOnBoolExpr - Emit a branch on a boolean condition (e.g. for an if 658/// statement) to the specified blocks. Based on the condition, this might try 659/// to simplify the codegen of the conditional based on the branch. 660/// 661void CodeGenFunction::EmitBranchOnBoolExpr(const Expr *Cond, 662 llvm::BasicBlock *TrueBlock, 663 llvm::BasicBlock *FalseBlock) { 664 Cond = Cond->IgnoreParens(); 665 666 if (const BinaryOperator *CondBOp = dyn_cast<BinaryOperator>(Cond)) { 667 // Handle X && Y in a condition. 668 if (CondBOp->getOpcode() == BO_LAnd) { 669 // If we have "1 && X", simplify the code. "0 && X" would have constant 670 // folded if the case was simple enough. 671 bool ConstantBool = false; 672 if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) && 673 ConstantBool) { 674 // br(1 && X) -> br(X). 675 return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); 676 } 677 678 // If we have "X && 1", simplify the code to use an uncond branch. 679 // "X && 0" would have been constant folded to 0. 680 if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) && 681 ConstantBool) { 682 // br(X && 1) -> br(X). 683 return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock); 684 } 685 686 // Emit the LHS as a conditional. If the LHS conditional is false, we 687 // want to jump to the FalseBlock. 688 llvm::BasicBlock *LHSTrue = createBasicBlock("land.lhs.true"); 689 690 ConditionalEvaluation eval(*this); 691 EmitBranchOnBoolExpr(CondBOp->getLHS(), LHSTrue, FalseBlock); 692 EmitBlock(LHSTrue); 693 694 // Any temporaries created here are conditional. 695 eval.begin(*this); 696 EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); 697 eval.end(*this); 698 699 return; 700 } 701 702 if (CondBOp->getOpcode() == BO_LOr) { 703 // If we have "0 || X", simplify the code. "1 || X" would have constant 704 // folded if the case was simple enough. 705 bool ConstantBool = false; 706 if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) && 707 !ConstantBool) { 708 // br(0 || X) -> br(X). 709 return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); 710 } 711 712 // If we have "X || 0", simplify the code to use an uncond branch. 713 // "X || 1" would have been constant folded to 1. 714 if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) && 715 !ConstantBool) { 716 // br(X || 0) -> br(X). 717 return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock); 718 } 719 720 // Emit the LHS as a conditional. If the LHS conditional is true, we 721 // want to jump to the TrueBlock. 722 llvm::BasicBlock *LHSFalse = createBasicBlock("lor.lhs.false"); 723 724 ConditionalEvaluation eval(*this); 725 EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, LHSFalse); 726 EmitBlock(LHSFalse); 727 728 // Any temporaries created here are conditional. 729 eval.begin(*this); 730 EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); 731 eval.end(*this); 732 733 return; 734 } 735 } 736 737 if (const UnaryOperator *CondUOp = dyn_cast<UnaryOperator>(Cond)) { 738 // br(!x, t, f) -> br(x, f, t) 739 if (CondUOp->getOpcode() == UO_LNot) 740 return EmitBranchOnBoolExpr(CondUOp->getSubExpr(), FalseBlock, TrueBlock); 741 } 742 743 if (const ConditionalOperator *CondOp = dyn_cast<ConditionalOperator>(Cond)) { 744 // br(c ? x : y, t, f) -> br(c, br(x, t, f), br(y, t, f)) 745 llvm::BasicBlock *LHSBlock = createBasicBlock("cond.true"); 746 llvm::BasicBlock *RHSBlock = createBasicBlock("cond.false"); 747 748 ConditionalEvaluation cond(*this); 749 EmitBranchOnBoolExpr(CondOp->getCond(), LHSBlock, RHSBlock); 750 751 cond.begin(*this); 752 EmitBlock(LHSBlock); 753 EmitBranchOnBoolExpr(CondOp->getLHS(), TrueBlock, FalseBlock); 754 cond.end(*this); 755 756 cond.begin(*this); 757 EmitBlock(RHSBlock); 758 EmitBranchOnBoolExpr(CondOp->getRHS(), TrueBlock, FalseBlock); 759 cond.end(*this); 760 761 return; 762 } 763 764 // Emit the code with the fully general case. 765 llvm::Value *CondV = EvaluateExprAsBool(Cond); 766 Builder.CreateCondBr(CondV, TrueBlock, FalseBlock); 767} 768 769/// ErrorUnsupported - Print out an error that codegen doesn't support the 770/// specified stmt yet. 771void CodeGenFunction::ErrorUnsupported(const Stmt *S, const char *Type, 772 bool OmitOnError) { 773 CGM.ErrorUnsupported(S, Type, OmitOnError); 774} 775 776/// emitNonZeroVLAInit - Emit the "zero" initialization of a 777/// variable-length array whose elements have a non-zero bit-pattern. 778/// 779/// \param baseType the inner-most element type of the array 780/// \param src - a char* pointing to the bit-pattern for a single 781/// base element of the array 782/// \param sizeInChars - the total size of the VLA, in chars 783static void emitNonZeroVLAInit(CodeGenFunction &CGF, QualType baseType, 784 llvm::Value *dest, llvm::Value *src, 785 llvm::Value *sizeInChars) { 786 std::pair<CharUnits,CharUnits> baseSizeAndAlign 787 = CGF.getContext().getTypeInfoInChars(baseType); 788 789 CGBuilderTy &Builder = CGF.Builder; 790 791 llvm::Value *baseSizeInChars 792 = llvm::ConstantInt::get(CGF.IntPtrTy, baseSizeAndAlign.first.getQuantity()); 793 794 llvm::Type *i8p = Builder.getInt8PtrTy(); 795 796 llvm::Value *begin = Builder.CreateBitCast(dest, i8p, "vla.begin"); 797 llvm::Value *end = Builder.CreateInBoundsGEP(dest, sizeInChars, "vla.end"); 798 799 llvm::BasicBlock *originBB = CGF.Builder.GetInsertBlock(); 800 llvm::BasicBlock *loopBB = CGF.createBasicBlock("vla-init.loop"); 801 llvm::BasicBlock *contBB = CGF.createBasicBlock("vla-init.cont"); 802 803 // Make a loop over the VLA. C99 guarantees that the VLA element 804 // count must be nonzero. 805 CGF.EmitBlock(loopBB); 806 807 llvm::PHINode *cur = Builder.CreatePHI(i8p, 2, "vla.cur"); 808 cur->addIncoming(begin, originBB); 809 810 // memcpy the individual element bit-pattern. 811 Builder.CreateMemCpy(cur, src, baseSizeInChars, 812 baseSizeAndAlign.second.getQuantity(), 813 /*volatile*/ false); 814 815 // Go to the next element. 816 llvm::Value *next = Builder.CreateConstInBoundsGEP1_32(cur, 1, "vla.next"); 817 818 // Leave if that's the end of the VLA. 819 llvm::Value *done = Builder.CreateICmpEQ(next, end, "vla-init.isdone"); 820 Builder.CreateCondBr(done, contBB, loopBB); 821 cur->addIncoming(next, loopBB); 822 823 CGF.EmitBlock(contBB); 824} 825 826void 827CodeGenFunction::EmitNullInitialization(llvm::Value *DestPtr, QualType Ty) { 828 // Ignore empty classes in C++. 829 if (getLangOpts().CPlusPlus) { 830 if (const RecordType *RT = Ty->getAs<RecordType>()) { 831 if (cast<CXXRecordDecl>(RT->getDecl())->isEmpty()) 832 return; 833 } 834 } 835 836 // Cast the dest ptr to the appropriate i8 pointer type. 837 unsigned DestAS = 838 cast<llvm::PointerType>(DestPtr->getType())->getAddressSpace(); 839 llvm::Type *BP = Builder.getInt8PtrTy(DestAS); 840 if (DestPtr->getType() != BP) 841 DestPtr = Builder.CreateBitCast(DestPtr, BP); 842 843 // Get size and alignment info for this aggregate. 844 std::pair<CharUnits, CharUnits> TypeInfo = 845 getContext().getTypeInfoInChars(Ty); 846 CharUnits Size = TypeInfo.first; 847 CharUnits Align = TypeInfo.second; 848 849 llvm::Value *SizeVal; 850 const VariableArrayType *vla; 851 852 // Don't bother emitting a zero-byte memset. 853 if (Size.isZero()) { 854 // But note that getTypeInfo returns 0 for a VLA. 855 if (const VariableArrayType *vlaType = 856 dyn_cast_or_null<VariableArrayType>( 857 getContext().getAsArrayType(Ty))) { 858 QualType eltType; 859 llvm::Value *numElts; 860 llvm::tie(numElts, eltType) = getVLASize(vlaType); 861 862 SizeVal = numElts; 863 CharUnits eltSize = getContext().getTypeSizeInChars(eltType); 864 if (!eltSize.isOne()) 865 SizeVal = Builder.CreateNUWMul(SizeVal, CGM.getSize(eltSize)); 866 vla = vlaType; 867 } else { 868 return; 869 } 870 } else { 871 SizeVal = CGM.getSize(Size); 872 vla = 0; 873 } 874 875 // If the type contains a pointer to data member we can't memset it to zero. 876 // Instead, create a null constant and copy it to the destination. 877 // TODO: there are other patterns besides zero that we can usefully memset, 878 // like -1, which happens to be the pattern used by member-pointers. 879 if (!CGM.getTypes().isZeroInitializable(Ty)) { 880 // For a VLA, emit a single element, then splat that over the VLA. 881 if (vla) Ty = getContext().getBaseElementType(vla); 882 883 llvm::Constant *NullConstant = CGM.EmitNullConstant(Ty); 884 885 llvm::GlobalVariable *NullVariable = 886 new llvm::GlobalVariable(CGM.getModule(), NullConstant->getType(), 887 /*isConstant=*/true, 888 llvm::GlobalVariable::PrivateLinkage, 889 NullConstant, Twine()); 890 llvm::Value *SrcPtr = 891 Builder.CreateBitCast(NullVariable, Builder.getInt8PtrTy()); 892 893 if (vla) return emitNonZeroVLAInit(*this, Ty, DestPtr, SrcPtr, SizeVal); 894 895 // Get and call the appropriate llvm.memcpy overload. 896 Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, Align.getQuantity(), false); 897 return; 898 } 899 900 // Otherwise, just memset the whole thing to zero. This is legal 901 // because in LLVM, all default initializers (other than the ones we just 902 // handled above) are guaranteed to have a bit pattern of all zeros. 903 Builder.CreateMemSet(DestPtr, Builder.getInt8(0), SizeVal, 904 Align.getQuantity(), false); 905} 906 907llvm::BlockAddress *CodeGenFunction::GetAddrOfLabel(const LabelDecl *L) { 908 // Make sure that there is a block for the indirect goto. 909 if (IndirectBranch == 0) 910 GetIndirectGotoBlock(); 911 912 llvm::BasicBlock *BB = getJumpDestForLabel(L).getBlock(); 913 914 // Make sure the indirect branch includes all of the address-taken blocks. 915 IndirectBranch->addDestination(BB); 916 return llvm::BlockAddress::get(CurFn, BB); 917} 918 919llvm::BasicBlock *CodeGenFunction::GetIndirectGotoBlock() { 920 // If we already made the indirect branch for indirect goto, return its block. 921 if (IndirectBranch) return IndirectBranch->getParent(); 922 923 CGBuilderTy TmpBuilder(createBasicBlock("indirectgoto")); 924 925 // Create the PHI node that indirect gotos will add entries to. 926 llvm::Value *DestVal = TmpBuilder.CreatePHI(Int8PtrTy, 0, 927 "indirect.goto.dest"); 928 929 // Create the indirect branch instruction. 930 IndirectBranch = TmpBuilder.CreateIndirectBr(DestVal); 931 return IndirectBranch->getParent(); 932} 933 934/// Computes the length of an array in elements, as well as the base 935/// element type and a properly-typed first element pointer. 936llvm::Value *CodeGenFunction::emitArrayLength(const ArrayType *origArrayType, 937 QualType &baseType, 938 llvm::Value *&addr) { 939 const ArrayType *arrayType = origArrayType; 940 941 // If it's a VLA, we have to load the stored size. Note that 942 // this is the size of the VLA in bytes, not its size in elements. 943 llvm::Value *numVLAElements = 0; 944 if (isa<VariableArrayType>(arrayType)) { 945 numVLAElements = getVLASize(cast<VariableArrayType>(arrayType)).first; 946 947 // Walk into all VLAs. This doesn't require changes to addr, 948 // which has type T* where T is the first non-VLA element type. 949 do { 950 QualType elementType = arrayType->getElementType(); 951 arrayType = getContext().getAsArrayType(elementType); 952 953 // If we only have VLA components, 'addr' requires no adjustment. 954 if (!arrayType) { 955 baseType = elementType; 956 return numVLAElements; 957 } 958 } while (isa<VariableArrayType>(arrayType)); 959 960 // We get out here only if we find a constant array type 961 // inside the VLA. 962 } 963 964 // We have some number of constant-length arrays, so addr should 965 // have LLVM type [M x [N x [...]]]*. Build a GEP that walks 966 // down to the first element of addr. 967 SmallVector<llvm::Value*, 8> gepIndices; 968 969 // GEP down to the array type. 970 llvm::ConstantInt *zero = Builder.getInt32(0); 971 gepIndices.push_back(zero); 972 973 uint64_t countFromCLAs = 1; 974 QualType eltType; 975 976 llvm::ArrayType *llvmArrayType = 977 dyn_cast<llvm::ArrayType>( 978 cast<llvm::PointerType>(addr->getType())->getElementType()); 979 while (llvmArrayType) { 980 assert(isa<ConstantArrayType>(arrayType)); 981 assert(cast<ConstantArrayType>(arrayType)->getSize().getZExtValue() 982 == llvmArrayType->getNumElements()); 983 984 gepIndices.push_back(zero); 985 countFromCLAs *= llvmArrayType->getNumElements(); 986 eltType = arrayType->getElementType(); 987 988 llvmArrayType = 989 dyn_cast<llvm::ArrayType>(llvmArrayType->getElementType()); 990 arrayType = getContext().getAsArrayType(arrayType->getElementType()); 991 assert((!llvmArrayType || arrayType) && 992 "LLVM and Clang types are out-of-synch"); 993 } 994 995 if (arrayType) { 996 // From this point onwards, the Clang array type has been emitted 997 // as some other type (probably a packed struct). Compute the array 998 // size, and just emit the 'begin' expression as a bitcast. 999 while (arrayType) { 1000 countFromCLAs *= 1001 cast<ConstantArrayType>(arrayType)->getSize().getZExtValue(); 1002 eltType = arrayType->getElementType(); 1003 arrayType = getContext().getAsArrayType(eltType); 1004 } 1005 1006 unsigned AddressSpace = addr->getType()->getPointerAddressSpace(); 1007 llvm::Type *BaseType = ConvertType(eltType)->getPointerTo(AddressSpace); 1008 addr = Builder.CreateBitCast(addr, BaseType, "array.begin"); 1009 } else { 1010 // Create the actual GEP. 1011 addr = Builder.CreateInBoundsGEP(addr, gepIndices, "array.begin"); 1012 } 1013 1014 baseType = eltType; 1015 1016 llvm::Value *numElements 1017 = llvm::ConstantInt::get(SizeTy, countFromCLAs); 1018 1019 // If we had any VLA dimensions, factor them in. 1020 if (numVLAElements) 1021 numElements = Builder.CreateNUWMul(numVLAElements, numElements); 1022 1023 return numElements; 1024} 1025 1026std::pair<llvm::Value*, QualType> 1027CodeGenFunction::getVLASize(QualType type) { 1028 const VariableArrayType *vla = getContext().getAsVariableArrayType(type); 1029 assert(vla && "type was not a variable array type!"); 1030 return getVLASize(vla); 1031} 1032 1033std::pair<llvm::Value*, QualType> 1034CodeGenFunction::getVLASize(const VariableArrayType *type) { 1035 // The number of elements so far; always size_t. 1036 llvm::Value *numElements = 0; 1037 1038 QualType elementType; 1039 do { 1040 elementType = type->getElementType(); 1041 llvm::Value *vlaSize = VLASizeMap[type->getSizeExpr()]; 1042 assert(vlaSize && "no size for VLA!"); 1043 assert(vlaSize->getType() == SizeTy); 1044 1045 if (!numElements) { 1046 numElements = vlaSize; 1047 } else { 1048 // It's undefined behavior if this wraps around, so mark it that way. 1049 // FIXME: Teach -fcatch-undefined-behavior to trap this. 1050 numElements = Builder.CreateNUWMul(numElements, vlaSize); 1051 } 1052 } while ((type = getContext().getAsVariableArrayType(elementType))); 1053 1054 return std::pair<llvm::Value*,QualType>(numElements, elementType); 1055} 1056 1057void CodeGenFunction::EmitVariablyModifiedType(QualType type) { 1058 assert(type->isVariablyModifiedType() && 1059 "Must pass variably modified type to EmitVLASizes!"); 1060 1061 EnsureInsertPoint(); 1062 1063 // We're going to walk down into the type and look for VLA 1064 // expressions. 1065 do { 1066 assert(type->isVariablyModifiedType()); 1067 1068 const Type *ty = type.getTypePtr(); 1069 switch (ty->getTypeClass()) { 1070 1071#define TYPE(Class, Base) 1072#define ABSTRACT_TYPE(Class, Base) 1073#define NON_CANONICAL_TYPE(Class, Base) 1074#define DEPENDENT_TYPE(Class, Base) case Type::Class: 1075#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) 1076#include "clang/AST/TypeNodes.def" 1077 llvm_unreachable("unexpected dependent type!"); 1078 1079 // These types are never variably-modified. 1080 case Type::Builtin: 1081 case Type::Complex: 1082 case Type::Vector: 1083 case Type::ExtVector: 1084 case Type::Record: 1085 case Type::Enum: 1086 case Type::Elaborated: 1087 case Type::TemplateSpecialization: 1088 case Type::ObjCObject: 1089 case Type::ObjCInterface: 1090 case Type::ObjCObjectPointer: 1091 llvm_unreachable("type class is never variably-modified!"); 1092 1093 case Type::Pointer: 1094 type = cast<PointerType>(ty)->getPointeeType(); 1095 break; 1096 1097 case Type::BlockPointer: 1098 type = cast<BlockPointerType>(ty)->getPointeeType(); 1099 break; 1100 1101 case Type::LValueReference: 1102 case Type::RValueReference: 1103 type = cast<ReferenceType>(ty)->getPointeeType(); 1104 break; 1105 1106 case Type::MemberPointer: 1107 type = cast<MemberPointerType>(ty)->getPointeeType(); 1108 break; 1109 1110 case Type::ConstantArray: 1111 case Type::IncompleteArray: 1112 // Losing element qualification here is fine. 1113 type = cast<ArrayType>(ty)->getElementType(); 1114 break; 1115 1116 case Type::VariableArray: { 1117 // Losing element qualification here is fine. 1118 const VariableArrayType *vat = cast<VariableArrayType>(ty); 1119 1120 // Unknown size indication requires no size computation. 1121 // Otherwise, evaluate and record it. 1122 if (const Expr *size = vat->getSizeExpr()) { 1123 // It's possible that we might have emitted this already, 1124 // e.g. with a typedef and a pointer to it. 1125 llvm::Value *&entry = VLASizeMap[size]; 1126 if (!entry) { 1127 llvm::Value *Size = EmitScalarExpr(size); 1128 1129 // C11 6.7.6.2p5: 1130 // If the size is an expression that is not an integer constant 1131 // expression [...] each time it is evaluated it shall have a value 1132 // greater than zero. 1133 if (getLangOpts().SanitizeVLABound && 1134 size->getType()->isSignedIntegerType()) { 1135 llvm::Value *Zero = llvm::Constant::getNullValue(Size->getType()); 1136 llvm::Constant *StaticArgs[] = { 1137 EmitCheckSourceLocation(size->getLocStart()), 1138 EmitCheckTypeDescriptor(size->getType()) 1139 }; 1140 EmitCheck(Builder.CreateICmpSGT(Size, Zero), 1141 "vla_bound_not_positive", StaticArgs, Size); 1142 } 1143 1144 // Always zexting here would be wrong if it weren't 1145 // undefined behavior to have a negative bound. 1146 entry = Builder.CreateIntCast(Size, SizeTy, /*signed*/ false); 1147 } 1148 } 1149 type = vat->getElementType(); 1150 break; 1151 } 1152 1153 case Type::FunctionProto: 1154 case Type::FunctionNoProto: 1155 type = cast<FunctionType>(ty)->getResultType(); 1156 break; 1157 1158 case Type::Paren: 1159 case Type::TypeOf: 1160 case Type::UnaryTransform: 1161 case Type::Attributed: 1162 case Type::SubstTemplateTypeParm: 1163 // Keep walking after single level desugaring. 1164 type = type.getSingleStepDesugaredType(getContext()); 1165 break; 1166 1167 case Type::Typedef: 1168 case Type::Decltype: 1169 case Type::Auto: 1170 // Stop walking: nothing to do. 1171 return; 1172 1173 case Type::TypeOfExpr: 1174 // Stop walking: emit typeof expression. 1175 EmitIgnoredExpr(cast<TypeOfExprType>(ty)->getUnderlyingExpr()); 1176 return; 1177 1178 case Type::Atomic: 1179 type = cast<AtomicType>(ty)->getValueType(); 1180 break; 1181 } 1182 } while (type->isVariablyModifiedType()); 1183} 1184 1185llvm::Value* CodeGenFunction::EmitVAListRef(const Expr* E) { 1186 if (getContext().getBuiltinVaListType()->isArrayType()) 1187 return EmitScalarExpr(E); 1188 return EmitLValue(E).getAddress(); 1189} 1190 1191void CodeGenFunction::EmitDeclRefExprDbgValue(const DeclRefExpr *E, 1192 llvm::Constant *Init) { 1193 assert (Init && "Invalid DeclRefExpr initializer!"); 1194 if (CGDebugInfo *Dbg = getDebugInfo()) 1195 if (CGM.getCodeGenOpts().getDebugInfo() >= CodeGenOptions::LimitedDebugInfo) 1196 Dbg->EmitGlobalVariable(E->getDecl(), Init); 1197} 1198 1199CodeGenFunction::PeepholeProtection 1200CodeGenFunction::protectFromPeepholes(RValue rvalue) { 1201 // At the moment, the only aggressive peephole we do in IR gen 1202 // is trunc(zext) folding, but if we add more, we can easily 1203 // extend this protection. 1204 1205 if (!rvalue.isScalar()) return PeepholeProtection(); 1206 llvm::Value *value = rvalue.getScalarVal(); 1207 if (!isa<llvm::ZExtInst>(value)) return PeepholeProtection(); 1208 1209 // Just make an extra bitcast. 1210 assert(HaveInsertPoint()); 1211 llvm::Instruction *inst = new llvm::BitCastInst(value, value->getType(), "", 1212 Builder.GetInsertBlock()); 1213 1214 PeepholeProtection protection; 1215 protection.Inst = inst; 1216 return protection; 1217} 1218 1219void CodeGenFunction::unprotectFromPeepholes(PeepholeProtection protection) { 1220 if (!protection.Inst) return; 1221 1222 // In theory, we could try to duplicate the peepholes now, but whatever. 1223 protection.Inst->eraseFromParent(); 1224} 1225 1226llvm::Value *CodeGenFunction::EmitAnnotationCall(llvm::Value *AnnotationFn, 1227 llvm::Value *AnnotatedVal, 1228 llvm::StringRef AnnotationStr, 1229 SourceLocation Location) { 1230 llvm::Value *Args[4] = { 1231 AnnotatedVal, 1232 Builder.CreateBitCast(CGM.EmitAnnotationString(AnnotationStr), Int8PtrTy), 1233 Builder.CreateBitCast(CGM.EmitAnnotationUnit(Location), Int8PtrTy), 1234 CGM.EmitAnnotationLineNo(Location) 1235 }; 1236 return Builder.CreateCall(AnnotationFn, Args); 1237} 1238 1239void CodeGenFunction::EmitVarAnnotations(const VarDecl *D, llvm::Value *V) { 1240 assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute"); 1241 // FIXME We create a new bitcast for every annotation because that's what 1242 // llvm-gcc was doing. 1243 for (specific_attr_iterator<AnnotateAttr> 1244 ai = D->specific_attr_begin<AnnotateAttr>(), 1245 ae = D->specific_attr_end<AnnotateAttr>(); ai != ae; ++ai) 1246 EmitAnnotationCall(CGM.getIntrinsic(llvm::Intrinsic::var_annotation), 1247 Builder.CreateBitCast(V, CGM.Int8PtrTy, V->getName()), 1248 (*ai)->getAnnotation(), D->getLocation()); 1249} 1250 1251llvm::Value *CodeGenFunction::EmitFieldAnnotations(const FieldDecl *D, 1252 llvm::Value *V) { 1253 assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute"); 1254 llvm::Type *VTy = V->getType(); 1255 llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::ptr_annotation, 1256 CGM.Int8PtrTy); 1257 1258 for (specific_attr_iterator<AnnotateAttr> 1259 ai = D->specific_attr_begin<AnnotateAttr>(), 1260 ae = D->specific_attr_end<AnnotateAttr>(); ai != ae; ++ai) { 1261 // FIXME Always emit the cast inst so we can differentiate between 1262 // annotation on the first field of a struct and annotation on the struct 1263 // itself. 1264 if (VTy != CGM.Int8PtrTy) 1265 V = Builder.Insert(new llvm::BitCastInst(V, CGM.Int8PtrTy)); 1266 V = EmitAnnotationCall(F, V, (*ai)->getAnnotation(), D->getLocation()); 1267 V = Builder.CreateBitCast(V, VTy); 1268 } 1269 1270 return V; 1271} 1272