CodeGenFunction.cpp revision 263508
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 "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/Basic/OpenCL.h" 25#include "clang/Basic/TargetInfo.h" 26#include "clang/CodeGen/CGFunctionInfo.h" 27#include "clang/Frontend/CodeGenOptions.h" 28#include "llvm/IR/DataLayout.h" 29#include "llvm/IR/Intrinsics.h" 30#include "llvm/IR/MDBuilder.h" 31#include "llvm/IR/Operator.h" 32using namespace clang; 33using namespace CodeGen; 34 35CodeGenFunction::CodeGenFunction(CodeGenModule &cgm, bool suppressNewContext) 36 : CodeGenTypeCache(cgm), CGM(cgm), Target(cgm.getTarget()), 37 Builder(cgm.getModule().getContext()), CapturedStmtInfo(0), 38 SanitizePerformTypeCheck(CGM.getSanOpts().Null | 39 CGM.getSanOpts().Alignment | 40 CGM.getSanOpts().ObjectSize | 41 CGM.getSanOpts().Vptr), 42 SanOpts(&CGM.getSanOpts()), AutoreleaseResult(false), BlockInfo(0), 43 BlockPointer(0), LambdaThisCaptureField(0), NormalCleanupDest(0), 44 NextCleanupDestIndex(1), FirstBlockInfo(0), EHResumeBlock(0), 45 ExceptionSlot(0), EHSelectorSlot(0), DebugInfo(CGM.getModuleDebugInfo()), 46 DisableDebugInfo(false), DidCallStackSave(false), IndirectBranch(0), 47 SwitchInsn(0), CaseRangeBlock(0), UnreachableBlock(0), NumReturnExprs(0), 48 NumSimpleReturnExprs(0), CXXABIThisDecl(0), CXXABIThisValue(0), 49 CXXThisValue(0), CXXDefaultInitExprThis(0), 50 CXXStructorImplicitParamDecl(0), CXXStructorImplicitParamValue(0), 51 OutermostConditional(0), CurLexicalScope(0), TerminateLandingPad(0), 52 TerminateHandler(0), TrapBB(0) { 53 if (!suppressNewContext) 54 CGM.getCXXABI().getMangleContext().startNewFunction(); 55 56 llvm::FastMathFlags FMF; 57 if (CGM.getLangOpts().FastMath) 58 FMF.setUnsafeAlgebra(); 59 if (CGM.getLangOpts().FiniteMathOnly) { 60 FMF.setNoNaNs(); 61 FMF.setNoInfs(); 62 } 63 Builder.SetFastMathFlags(FMF); 64} 65 66CodeGenFunction::~CodeGenFunction() { 67 assert(LifetimeExtendedCleanupStack.empty() && "failed to emit a cleanup"); 68 69 // If there are any unclaimed block infos, go ahead and destroy them 70 // now. This can happen if IR-gen gets clever and skips evaluating 71 // something. 72 if (FirstBlockInfo) 73 destroyBlockInfos(FirstBlockInfo); 74} 75 76 77llvm::Type *CodeGenFunction::ConvertTypeForMem(QualType T) { 78 return CGM.getTypes().ConvertTypeForMem(T); 79} 80 81llvm::Type *CodeGenFunction::ConvertType(QualType T) { 82 return CGM.getTypes().ConvertType(T); 83} 84 85TypeEvaluationKind CodeGenFunction::getEvaluationKind(QualType type) { 86 type = type.getCanonicalType(); 87 while (true) { 88 switch (type->getTypeClass()) { 89#define TYPE(name, parent) 90#define ABSTRACT_TYPE(name, parent) 91#define NON_CANONICAL_TYPE(name, parent) case Type::name: 92#define DEPENDENT_TYPE(name, parent) case Type::name: 93#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(name, parent) case Type::name: 94#include "clang/AST/TypeNodes.def" 95 llvm_unreachable("non-canonical or dependent type in IR-generation"); 96 97 case Type::Auto: 98 llvm_unreachable("undeduced auto type in IR-generation"); 99 100 // Various scalar types. 101 case Type::Builtin: 102 case Type::Pointer: 103 case Type::BlockPointer: 104 case Type::LValueReference: 105 case Type::RValueReference: 106 case Type::MemberPointer: 107 case Type::Vector: 108 case Type::ExtVector: 109 case Type::FunctionProto: 110 case Type::FunctionNoProto: 111 case Type::Enum: 112 case Type::ObjCObjectPointer: 113 return TEK_Scalar; 114 115 // Complexes. 116 case Type::Complex: 117 return TEK_Complex; 118 119 // Arrays, records, and Objective-C objects. 120 case Type::ConstantArray: 121 case Type::IncompleteArray: 122 case Type::VariableArray: 123 case Type::Record: 124 case Type::ObjCObject: 125 case Type::ObjCInterface: 126 return TEK_Aggregate; 127 128 // We operate on atomic values according to their underlying type. 129 case Type::Atomic: 130 type = cast<AtomicType>(type)->getValueType(); 131 continue; 132 } 133 llvm_unreachable("unknown type kind!"); 134 } 135} 136 137void CodeGenFunction::EmitReturnBlock() { 138 // For cleanliness, we try to avoid emitting the return block for 139 // simple cases. 140 llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); 141 142 if (CurBB) { 143 assert(!CurBB->getTerminator() && "Unexpected terminated block."); 144 145 // We have a valid insert point, reuse it if it is empty or there are no 146 // explicit jumps to the return block. 147 if (CurBB->empty() || ReturnBlock.getBlock()->use_empty()) { 148 ReturnBlock.getBlock()->replaceAllUsesWith(CurBB); 149 delete ReturnBlock.getBlock(); 150 } else 151 EmitBlock(ReturnBlock.getBlock()); 152 return; 153 } 154 155 // Otherwise, if the return block is the target of a single direct 156 // branch then we can just put the code in that block instead. This 157 // cleans up functions which started with a unified return block. 158 if (ReturnBlock.getBlock()->hasOneUse()) { 159 llvm::BranchInst *BI = 160 dyn_cast<llvm::BranchInst>(*ReturnBlock.getBlock()->use_begin()); 161 if (BI && BI->isUnconditional() && 162 BI->getSuccessor(0) == ReturnBlock.getBlock()) { 163 // Reset insertion point, including debug location, and delete the 164 // branch. This is really subtle and only works because the next change 165 // in location will hit the caching in CGDebugInfo::EmitLocation and not 166 // override this. 167 Builder.SetCurrentDebugLocation(BI->getDebugLoc()); 168 Builder.SetInsertPoint(BI->getParent()); 169 BI->eraseFromParent(); 170 delete ReturnBlock.getBlock(); 171 return; 172 } 173 } 174 175 // FIXME: We are at an unreachable point, there is no reason to emit the block 176 // unless it has uses. However, we still need a place to put the debug 177 // region.end for now. 178 179 EmitBlock(ReturnBlock.getBlock()); 180} 181 182static void EmitIfUsed(CodeGenFunction &CGF, llvm::BasicBlock *BB) { 183 if (!BB) return; 184 if (!BB->use_empty()) 185 return CGF.CurFn->getBasicBlockList().push_back(BB); 186 delete BB; 187} 188 189void CodeGenFunction::FinishFunction(SourceLocation EndLoc) { 190 assert(BreakContinueStack.empty() && 191 "mismatched push/pop in break/continue stack!"); 192 193 bool OnlySimpleReturnStmts = NumSimpleReturnExprs > 0 194 && NumSimpleReturnExprs == NumReturnExprs 195 && ReturnBlock.getBlock()->use_empty(); 196 // Usually the return expression is evaluated before the cleanup 197 // code. If the function contains only a simple return statement, 198 // such as a constant, the location before the cleanup code becomes 199 // the last useful breakpoint in the function, because the simple 200 // return expression will be evaluated after the cleanup code. To be 201 // safe, set the debug location for cleanup code to the location of 202 // the return statement. Otherwise the cleanup code should be at the 203 // end of the function's lexical scope. 204 // 205 // If there are multiple branches to the return block, the branch 206 // instructions will get the location of the return statements and 207 // all will be fine. 208 if (CGDebugInfo *DI = getDebugInfo()) { 209 if (OnlySimpleReturnStmts) 210 DI->EmitLocation(Builder, LastStopPoint); 211 else 212 DI->EmitLocation(Builder, EndLoc); 213 } 214 215 // Pop any cleanups that might have been associated with the 216 // parameters. Do this in whatever block we're currently in; it's 217 // important to do this before we enter the return block or return 218 // edges will be *really* confused. 219 bool EmitRetDbgLoc = true; 220 if (EHStack.stable_begin() != PrologueCleanupDepth) { 221 PopCleanupBlocks(PrologueCleanupDepth); 222 223 // Make sure the line table doesn't jump back into the body for 224 // the ret after it's been at EndLoc. 225 EmitRetDbgLoc = false; 226 227 if (CGDebugInfo *DI = getDebugInfo()) 228 if (OnlySimpleReturnStmts) 229 DI->EmitLocation(Builder, EndLoc); 230 } 231 232 // Emit function epilog (to return). 233 EmitReturnBlock(); 234 235 if (ShouldInstrumentFunction()) 236 EmitFunctionInstrumentation("__cyg_profile_func_exit"); 237 238 // Emit debug descriptor for function end. 239 if (CGDebugInfo *DI = getDebugInfo()) { 240 DI->EmitFunctionEnd(Builder); 241 } 242 243 EmitFunctionEpilog(*CurFnInfo, EmitRetDbgLoc, EndLoc); 244 EmitEndEHSpec(CurCodeDecl); 245 246 assert(EHStack.empty() && 247 "did not remove all scopes from cleanup stack!"); 248 249 // If someone did an indirect goto, emit the indirect goto block at the end of 250 // the function. 251 if (IndirectBranch) { 252 EmitBlock(IndirectBranch->getParent()); 253 Builder.ClearInsertionPoint(); 254 } 255 256 // Remove the AllocaInsertPt instruction, which is just a convenience for us. 257 llvm::Instruction *Ptr = AllocaInsertPt; 258 AllocaInsertPt = 0; 259 Ptr->eraseFromParent(); 260 261 // If someone took the address of a label but never did an indirect goto, we 262 // made a zero entry PHI node, which is illegal, zap it now. 263 if (IndirectBranch) { 264 llvm::PHINode *PN = cast<llvm::PHINode>(IndirectBranch->getAddress()); 265 if (PN->getNumIncomingValues() == 0) { 266 PN->replaceAllUsesWith(llvm::UndefValue::get(PN->getType())); 267 PN->eraseFromParent(); 268 } 269 } 270 271 EmitIfUsed(*this, EHResumeBlock); 272 EmitIfUsed(*this, TerminateLandingPad); 273 EmitIfUsed(*this, TerminateHandler); 274 EmitIfUsed(*this, UnreachableBlock); 275 276 if (CGM.getCodeGenOpts().EmitDeclMetadata) 277 EmitDeclMetadata(); 278} 279 280/// ShouldInstrumentFunction - Return true if the current function should be 281/// instrumented with __cyg_profile_func_* calls 282bool CodeGenFunction::ShouldInstrumentFunction() { 283 if (!CGM.getCodeGenOpts().InstrumentFunctions) 284 return false; 285 if (!CurFuncDecl || CurFuncDecl->hasAttr<NoInstrumentFunctionAttr>()) 286 return false; 287 return true; 288} 289 290/// EmitFunctionInstrumentation - Emit LLVM code to call the specified 291/// instrumentation function with the current function and the call site, if 292/// function instrumentation is enabled. 293void CodeGenFunction::EmitFunctionInstrumentation(const char *Fn) { 294 // void __cyg_profile_func_{enter,exit} (void *this_fn, void *call_site); 295 llvm::PointerType *PointerTy = Int8PtrTy; 296 llvm::Type *ProfileFuncArgs[] = { PointerTy, PointerTy }; 297 llvm::FunctionType *FunctionTy = 298 llvm::FunctionType::get(VoidTy, ProfileFuncArgs, false); 299 300 llvm::Constant *F = CGM.CreateRuntimeFunction(FunctionTy, Fn); 301 llvm::CallInst *CallSite = Builder.CreateCall( 302 CGM.getIntrinsic(llvm::Intrinsic::returnaddress), 303 llvm::ConstantInt::get(Int32Ty, 0), 304 "callsite"); 305 306 llvm::Value *args[] = { 307 llvm::ConstantExpr::getBitCast(CurFn, PointerTy), 308 CallSite 309 }; 310 311 EmitNounwindRuntimeCall(F, args); 312} 313 314void CodeGenFunction::EmitMCountInstrumentation() { 315 llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false); 316 317 llvm::Constant *MCountFn = 318 CGM.CreateRuntimeFunction(FTy, getTarget().getMCountName()); 319 EmitNounwindRuntimeCall(MCountFn); 320} 321 322// OpenCL v1.2 s5.6.4.6 allows the compiler to store kernel argument 323// information in the program executable. The argument information stored 324// includes the argument name, its type, the address and access qualifiers used. 325static void GenOpenCLArgMetadata(const FunctionDecl *FD, llvm::Function *Fn, 326 CodeGenModule &CGM,llvm::LLVMContext &Context, 327 SmallVector <llvm::Value*, 5> &kernelMDArgs, 328 CGBuilderTy& Builder, ASTContext &ASTCtx) { 329 // Create MDNodes that represent the kernel arg metadata. 330 // Each MDNode is a list in the form of "key", N number of values which is 331 // the same number of values as their are kernel arguments. 332 333 // MDNode for the kernel argument address space qualifiers. 334 SmallVector<llvm::Value*, 8> addressQuals; 335 addressQuals.push_back(llvm::MDString::get(Context, "kernel_arg_addr_space")); 336 337 // MDNode for the kernel argument access qualifiers (images only). 338 SmallVector<llvm::Value*, 8> accessQuals; 339 accessQuals.push_back(llvm::MDString::get(Context, "kernel_arg_access_qual")); 340 341 // MDNode for the kernel argument type names. 342 SmallVector<llvm::Value*, 8> argTypeNames; 343 argTypeNames.push_back(llvm::MDString::get(Context, "kernel_arg_type")); 344 345 // MDNode for the kernel argument type qualifiers. 346 SmallVector<llvm::Value*, 8> argTypeQuals; 347 argTypeQuals.push_back(llvm::MDString::get(Context, "kernel_arg_type_qual")); 348 349 // MDNode for the kernel argument names. 350 SmallVector<llvm::Value*, 8> argNames; 351 argNames.push_back(llvm::MDString::get(Context, "kernel_arg_name")); 352 353 for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i) { 354 const ParmVarDecl *parm = FD->getParamDecl(i); 355 QualType ty = parm->getType(); 356 std::string typeQuals; 357 358 if (ty->isPointerType()) { 359 QualType pointeeTy = ty->getPointeeType(); 360 361 // Get address qualifier. 362 addressQuals.push_back(Builder.getInt32(ASTCtx.getTargetAddressSpace( 363 pointeeTy.getAddressSpace()))); 364 365 // Get argument type name. 366 std::string typeName = pointeeTy.getUnqualifiedType().getAsString() + "*"; 367 368 // Turn "unsigned type" to "utype" 369 std::string::size_type pos = typeName.find("unsigned"); 370 if (pos != std::string::npos) 371 typeName.erase(pos+1, 8); 372 373 argTypeNames.push_back(llvm::MDString::get(Context, typeName)); 374 375 // Get argument type qualifiers: 376 if (ty.isRestrictQualified()) 377 typeQuals = "restrict"; 378 if (pointeeTy.isConstQualified() || 379 (pointeeTy.getAddressSpace() == LangAS::opencl_constant)) 380 typeQuals += typeQuals.empty() ? "const" : " const"; 381 if (pointeeTy.isVolatileQualified()) 382 typeQuals += typeQuals.empty() ? "volatile" : " volatile"; 383 } else { 384 addressQuals.push_back(Builder.getInt32(0)); 385 386 // Get argument type name. 387 std::string typeName = ty.getUnqualifiedType().getAsString(); 388 389 // Turn "unsigned type" to "utype" 390 std::string::size_type pos = typeName.find("unsigned"); 391 if (pos != std::string::npos) 392 typeName.erase(pos+1, 8); 393 394 argTypeNames.push_back(llvm::MDString::get(Context, typeName)); 395 396 // Get argument type qualifiers: 397 if (ty.isConstQualified()) 398 typeQuals = "const"; 399 if (ty.isVolatileQualified()) 400 typeQuals += typeQuals.empty() ? "volatile" : " volatile"; 401 } 402 403 argTypeQuals.push_back(llvm::MDString::get(Context, typeQuals)); 404 405 // Get image access qualifier: 406 if (ty->isImageType()) { 407 if (parm->hasAttr<OpenCLImageAccessAttr>() && 408 parm->getAttr<OpenCLImageAccessAttr>()->getAccess() == CLIA_write_only) 409 accessQuals.push_back(llvm::MDString::get(Context, "write_only")); 410 else 411 accessQuals.push_back(llvm::MDString::get(Context, "read_only")); 412 } else 413 accessQuals.push_back(llvm::MDString::get(Context, "none")); 414 415 // Get argument name. 416 argNames.push_back(llvm::MDString::get(Context, parm->getName())); 417 } 418 419 kernelMDArgs.push_back(llvm::MDNode::get(Context, addressQuals)); 420 kernelMDArgs.push_back(llvm::MDNode::get(Context, accessQuals)); 421 kernelMDArgs.push_back(llvm::MDNode::get(Context, argTypeNames)); 422 kernelMDArgs.push_back(llvm::MDNode::get(Context, argTypeQuals)); 423 kernelMDArgs.push_back(llvm::MDNode::get(Context, argNames)); 424} 425 426void CodeGenFunction::EmitOpenCLKernelMetadata(const FunctionDecl *FD, 427 llvm::Function *Fn) 428{ 429 if (!FD->hasAttr<OpenCLKernelAttr>()) 430 return; 431 432 llvm::LLVMContext &Context = getLLVMContext(); 433 434 SmallVector <llvm::Value*, 5> kernelMDArgs; 435 kernelMDArgs.push_back(Fn); 436 437 if (CGM.getCodeGenOpts().EmitOpenCLArgMetadata) 438 GenOpenCLArgMetadata(FD, Fn, CGM, Context, kernelMDArgs, 439 Builder, getContext()); 440 441 if (FD->hasAttr<VecTypeHintAttr>()) { 442 VecTypeHintAttr *attr = FD->getAttr<VecTypeHintAttr>(); 443 QualType hintQTy = attr->getTypeHint(); 444 const ExtVectorType *hintEltQTy = hintQTy->getAs<ExtVectorType>(); 445 bool isSignedInteger = 446 hintQTy->isSignedIntegerType() || 447 (hintEltQTy && hintEltQTy->getElementType()->isSignedIntegerType()); 448 llvm::Value *attrMDArgs[] = { 449 llvm::MDString::get(Context, "vec_type_hint"), 450 llvm::UndefValue::get(CGM.getTypes().ConvertType(attr->getTypeHint())), 451 llvm::ConstantInt::get( 452 llvm::IntegerType::get(Context, 32), 453 llvm::APInt(32, (uint64_t)(isSignedInteger ? 1 : 0))) 454 }; 455 kernelMDArgs.push_back(llvm::MDNode::get(Context, attrMDArgs)); 456 } 457 458 if (FD->hasAttr<WorkGroupSizeHintAttr>()) { 459 WorkGroupSizeHintAttr *attr = FD->getAttr<WorkGroupSizeHintAttr>(); 460 llvm::Value *attrMDArgs[] = { 461 llvm::MDString::get(Context, "work_group_size_hint"), 462 Builder.getInt32(attr->getXDim()), 463 Builder.getInt32(attr->getYDim()), 464 Builder.getInt32(attr->getZDim()) 465 }; 466 kernelMDArgs.push_back(llvm::MDNode::get(Context, attrMDArgs)); 467 } 468 469 if (FD->hasAttr<ReqdWorkGroupSizeAttr>()) { 470 ReqdWorkGroupSizeAttr *attr = FD->getAttr<ReqdWorkGroupSizeAttr>(); 471 llvm::Value *attrMDArgs[] = { 472 llvm::MDString::get(Context, "reqd_work_group_size"), 473 Builder.getInt32(attr->getXDim()), 474 Builder.getInt32(attr->getYDim()), 475 Builder.getInt32(attr->getZDim()) 476 }; 477 kernelMDArgs.push_back(llvm::MDNode::get(Context, attrMDArgs)); 478 } 479 480 llvm::MDNode *kernelMDNode = llvm::MDNode::get(Context, kernelMDArgs); 481 llvm::NamedMDNode *OpenCLKernelMetadata = 482 CGM.getModule().getOrInsertNamedMetadata("opencl.kernels"); 483 OpenCLKernelMetadata->addOperand(kernelMDNode); 484} 485 486void CodeGenFunction::StartFunction(GlobalDecl GD, 487 QualType RetTy, 488 llvm::Function *Fn, 489 const CGFunctionInfo &FnInfo, 490 const FunctionArgList &Args, 491 SourceLocation StartLoc) { 492 const Decl *D = GD.getDecl(); 493 494 DidCallStackSave = false; 495 CurCodeDecl = D; 496 CurFuncDecl = (D ? D->getNonClosureContext() : 0); 497 FnRetTy = RetTy; 498 CurFn = Fn; 499 CurFnInfo = &FnInfo; 500 assert(CurFn->isDeclaration() && "Function already has body?"); 501 502 if (CGM.getSanitizerBlacklist().isIn(*Fn)) { 503 SanOpts = &SanitizerOptions::Disabled; 504 SanitizePerformTypeCheck = false; 505 } 506 507 // Pass inline keyword to optimizer if it appears explicitly on any 508 // declaration. 509 if (!CGM.getCodeGenOpts().NoInline) 510 if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) 511 for (FunctionDecl::redecl_iterator RI = FD->redecls_begin(), 512 RE = FD->redecls_end(); RI != RE; ++RI) 513 if (RI->isInlineSpecified()) { 514 Fn->addFnAttr(llvm::Attribute::InlineHint); 515 break; 516 } 517 518 if (getLangOpts().OpenCL) { 519 // Add metadata for a kernel function. 520 if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) 521 EmitOpenCLKernelMetadata(FD, Fn); 522 } 523 524 // If we are checking function types, emit a function type signature as 525 // prefix data. 526 if (getLangOpts().CPlusPlus && SanOpts->Function) { 527 if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) { 528 if (llvm::Constant *PrefixSig = 529 CGM.getTargetCodeGenInfo().getUBSanFunctionSignature(CGM)) { 530 llvm::Constant *FTRTTIConst = 531 CGM.GetAddrOfRTTIDescriptor(FD->getType(), /*ForEH=*/true); 532 llvm::Constant *PrefixStructElems[] = { PrefixSig, FTRTTIConst }; 533 llvm::Constant *PrefixStructConst = 534 llvm::ConstantStruct::getAnon(PrefixStructElems, /*Packed=*/true); 535 Fn->setPrefixData(PrefixStructConst); 536 } 537 } 538 } 539 540 llvm::BasicBlock *EntryBB = createBasicBlock("entry", CurFn); 541 542 // Create a marker to make it easy to insert allocas into the entryblock 543 // later. Don't create this with the builder, because we don't want it 544 // folded. 545 llvm::Value *Undef = llvm::UndefValue::get(Int32Ty); 546 AllocaInsertPt = new llvm::BitCastInst(Undef, Int32Ty, "", EntryBB); 547 if (Builder.isNamePreserving()) 548 AllocaInsertPt->setName("allocapt"); 549 550 ReturnBlock = getJumpDestInCurrentScope("return"); 551 552 Builder.SetInsertPoint(EntryBB); 553 554 // Emit subprogram debug descriptor. 555 if (CGDebugInfo *DI = getDebugInfo()) { 556 SmallVector<QualType, 16> ArgTypes; 557 for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end(); 558 i != e; ++i) { 559 ArgTypes.push_back((*i)->getType()); 560 } 561 562 QualType FnType = 563 getContext().getFunctionType(RetTy, ArgTypes, 564 FunctionProtoType::ExtProtoInfo()); 565 566 DI->setLocation(StartLoc); 567 DI->EmitFunctionStart(GD, FnType, CurFn, Builder); 568 } 569 570 if (ShouldInstrumentFunction()) 571 EmitFunctionInstrumentation("__cyg_profile_func_enter"); 572 573 if (CGM.getCodeGenOpts().InstrumentForProfiling) 574 EmitMCountInstrumentation(); 575 576 if (RetTy->isVoidType()) { 577 // Void type; nothing to return. 578 ReturnValue = 0; 579 } else if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::Indirect && 580 !hasScalarEvaluationKind(CurFnInfo->getReturnType())) { 581 // Indirect aggregate return; emit returned value directly into sret slot. 582 // This reduces code size, and affects correctness in C++. 583 ReturnValue = CurFn->arg_begin(); 584 } else { 585 ReturnValue = CreateIRTemp(RetTy, "retval"); 586 587 // Tell the epilog emitter to autorelease the result. We do this 588 // now so that various specialized functions can suppress it 589 // during their IR-generation. 590 if (getLangOpts().ObjCAutoRefCount && 591 !CurFnInfo->isReturnsRetained() && 592 RetTy->isObjCRetainableType()) 593 AutoreleaseResult = true; 594 } 595 596 EmitStartEHSpec(CurCodeDecl); 597 598 PrologueCleanupDepth = EHStack.stable_begin(); 599 EmitFunctionProlog(*CurFnInfo, CurFn, Args); 600 601 if (D && isa<CXXMethodDecl>(D) && cast<CXXMethodDecl>(D)->isInstance()) { 602 CGM.getCXXABI().EmitInstanceFunctionProlog(*this); 603 const CXXMethodDecl *MD = cast<CXXMethodDecl>(D); 604 if (MD->getParent()->isLambda() && 605 MD->getOverloadedOperator() == OO_Call) { 606 // We're in a lambda; figure out the captures. 607 MD->getParent()->getCaptureFields(LambdaCaptureFields, 608 LambdaThisCaptureField); 609 if (LambdaThisCaptureField) { 610 // If this lambda captures this, load it. 611 LValue ThisLValue = EmitLValueForLambdaField(LambdaThisCaptureField); 612 CXXThisValue = EmitLoadOfLValue(ThisLValue, 613 SourceLocation()).getScalarVal(); 614 } 615 } else { 616 // Not in a lambda; just use 'this' from the method. 617 // FIXME: Should we generate a new load for each use of 'this'? The 618 // fast register allocator would be happier... 619 CXXThisValue = CXXABIThisValue; 620 } 621 } 622 623 // If any of the arguments have a variably modified type, make sure to 624 // emit the type size. 625 for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end(); 626 i != e; ++i) { 627 const VarDecl *VD = *i; 628 629 // Dig out the type as written from ParmVarDecls; it's unclear whether 630 // the standard (C99 6.9.1p10) requires this, but we're following the 631 // precedent set by gcc. 632 QualType Ty; 633 if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD)) 634 Ty = PVD->getOriginalType(); 635 else 636 Ty = VD->getType(); 637 638 if (Ty->isVariablyModifiedType()) 639 EmitVariablyModifiedType(Ty); 640 } 641 // Emit a location at the end of the prologue. 642 if (CGDebugInfo *DI = getDebugInfo()) 643 DI->EmitLocation(Builder, StartLoc); 644} 645 646void CodeGenFunction::EmitFunctionBody(FunctionArgList &Args, 647 const Stmt *Body) { 648 if (const CompoundStmt *S = dyn_cast<CompoundStmt>(Body)) 649 EmitCompoundStmtWithoutScope(*S); 650 else 651 EmitStmt(Body); 652} 653 654/// Tries to mark the given function nounwind based on the 655/// non-existence of any throwing calls within it. We believe this is 656/// lightweight enough to do at -O0. 657static void TryMarkNoThrow(llvm::Function *F) { 658 // LLVM treats 'nounwind' on a function as part of the type, so we 659 // can't do this on functions that can be overwritten. 660 if (F->mayBeOverridden()) return; 661 662 for (llvm::Function::iterator FI = F->begin(), FE = F->end(); FI != FE; ++FI) 663 for (llvm::BasicBlock::iterator 664 BI = FI->begin(), BE = FI->end(); BI != BE; ++BI) 665 if (llvm::CallInst *Call = dyn_cast<llvm::CallInst>(&*BI)) { 666 if (!Call->doesNotThrow()) 667 return; 668 } else if (isa<llvm::ResumeInst>(&*BI)) { 669 return; 670 } 671 F->setDoesNotThrow(); 672} 673 674static void EmitSizedDeallocationFunction(CodeGenFunction &CGF, 675 const FunctionDecl *UnsizedDealloc) { 676 // This is a weak discardable definition of the sized deallocation function. 677 CGF.CurFn->setLinkage(llvm::Function::LinkOnceAnyLinkage); 678 679 // Call the unsized deallocation function and forward the first argument 680 // unchanged. 681 llvm::Constant *Unsized = CGF.CGM.GetAddrOfFunction(UnsizedDealloc); 682 CGF.Builder.CreateCall(Unsized, &*CGF.CurFn->arg_begin()); 683} 684 685void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn, 686 const CGFunctionInfo &FnInfo) { 687 const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); 688 689 // Check if we should generate debug info for this function. 690 if (FD->hasAttr<NoDebugAttr>()) 691 DebugInfo = NULL; // disable debug info indefinitely for this function 692 693 FunctionArgList Args; 694 QualType ResTy = FD->getResultType(); 695 696 CurGD = GD; 697 const CXXMethodDecl *MD; 698 if ((MD = dyn_cast<CXXMethodDecl>(FD)) && MD->isInstance()) { 699 if (CGM.getCXXABI().HasThisReturn(GD)) 700 ResTy = MD->getThisType(getContext()); 701 CGM.getCXXABI().BuildInstanceFunctionParams(*this, ResTy, Args); 702 } 703 704 for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i) 705 Args.push_back(FD->getParamDecl(i)); 706 707 SourceRange BodyRange; 708 if (Stmt *Body = FD->getBody()) BodyRange = Body->getSourceRange(); 709 CurEHLocation = BodyRange.getEnd(); 710 711 // Emit the standard function prologue. 712 StartFunction(GD, ResTy, Fn, FnInfo, Args, BodyRange.getBegin()); 713 714 // Generate the body of the function. 715 if (isa<CXXDestructorDecl>(FD)) 716 EmitDestructorBody(Args); 717 else if (isa<CXXConstructorDecl>(FD)) 718 EmitConstructorBody(Args); 719 else if (getLangOpts().CUDA && 720 !CGM.getCodeGenOpts().CUDAIsDevice && 721 FD->hasAttr<CUDAGlobalAttr>()) 722 CGM.getCUDARuntime().EmitDeviceStubBody(*this, Args); 723 else if (isa<CXXConversionDecl>(FD) && 724 cast<CXXConversionDecl>(FD)->isLambdaToBlockPointerConversion()) { 725 // The lambda conversion to block pointer is special; the semantics can't be 726 // expressed in the AST, so IRGen needs to special-case it. 727 EmitLambdaToBlockPointerBody(Args); 728 } else if (isa<CXXMethodDecl>(FD) && 729 cast<CXXMethodDecl>(FD)->isLambdaStaticInvoker()) { 730 // The lambda static invoker function is special, because it forwards or 731 // clones the body of the function call operator (but is actually static). 732 EmitLambdaStaticInvokeFunction(cast<CXXMethodDecl>(FD)); 733 } else if (FD->isDefaulted() && isa<CXXMethodDecl>(FD) && 734 (cast<CXXMethodDecl>(FD)->isCopyAssignmentOperator() || 735 cast<CXXMethodDecl>(FD)->isMoveAssignmentOperator())) { 736 // Implicit copy-assignment gets the same special treatment as implicit 737 // copy-constructors. 738 emitImplicitAssignmentOperatorBody(Args); 739 } else if (Stmt *Body = FD->getBody()) { 740 EmitFunctionBody(Args, Body); 741 } else if (FunctionDecl *UnsizedDealloc = 742 FD->getCorrespondingUnsizedGlobalDeallocationFunction()) { 743 // Global sized deallocation functions get an implicit weak definition if 744 // they don't have an explicit definition. 745 EmitSizedDeallocationFunction(*this, UnsizedDealloc); 746 } else 747 llvm_unreachable("no definition for emitted function"); 748 749 // C++11 [stmt.return]p2: 750 // Flowing off the end of a function [...] results in undefined behavior in 751 // a value-returning function. 752 // C11 6.9.1p12: 753 // If the '}' that terminates a function is reached, and the value of the 754 // function call is used by the caller, the behavior is undefined. 755 if (getLangOpts().CPlusPlus && !FD->hasImplicitReturnZero() && 756 !FD->getResultType()->isVoidType() && Builder.GetInsertBlock()) { 757 if (SanOpts->Return) 758 EmitCheck(Builder.getFalse(), "missing_return", 759 EmitCheckSourceLocation(FD->getLocation()), 760 ArrayRef<llvm::Value *>(), CRK_Unrecoverable); 761 else if (CGM.getCodeGenOpts().OptimizationLevel == 0) 762 Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::trap)); 763 Builder.CreateUnreachable(); 764 Builder.ClearInsertionPoint(); 765 } 766 767 // Emit the standard function epilogue. 768 FinishFunction(BodyRange.getEnd()); 769 770 // If we haven't marked the function nothrow through other means, do 771 // a quick pass now to see if we can. 772 if (!CurFn->doesNotThrow()) 773 TryMarkNoThrow(CurFn); 774} 775 776/// ContainsLabel - Return true if the statement contains a label in it. If 777/// this statement is not executed normally, it not containing a label means 778/// that we can just remove the code. 779bool CodeGenFunction::ContainsLabel(const Stmt *S, bool IgnoreCaseStmts) { 780 // Null statement, not a label! 781 if (S == 0) return false; 782 783 // If this is a label, we have to emit the code, consider something like: 784 // if (0) { ... foo: bar(); } goto foo; 785 // 786 // TODO: If anyone cared, we could track __label__'s, since we know that you 787 // can't jump to one from outside their declared region. 788 if (isa<LabelStmt>(S)) 789 return true; 790 791 // If this is a case/default statement, and we haven't seen a switch, we have 792 // to emit the code. 793 if (isa<SwitchCase>(S) && !IgnoreCaseStmts) 794 return true; 795 796 // If this is a switch statement, we want to ignore cases below it. 797 if (isa<SwitchStmt>(S)) 798 IgnoreCaseStmts = true; 799 800 // Scan subexpressions for verboten labels. 801 for (Stmt::const_child_range I = S->children(); I; ++I) 802 if (ContainsLabel(*I, IgnoreCaseStmts)) 803 return true; 804 805 return false; 806} 807 808/// containsBreak - Return true if the statement contains a break out of it. 809/// If the statement (recursively) contains a switch or loop with a break 810/// inside of it, this is fine. 811bool CodeGenFunction::containsBreak(const Stmt *S) { 812 // Null statement, not a label! 813 if (S == 0) return false; 814 815 // If this is a switch or loop that defines its own break scope, then we can 816 // include it and anything inside of it. 817 if (isa<SwitchStmt>(S) || isa<WhileStmt>(S) || isa<DoStmt>(S) || 818 isa<ForStmt>(S)) 819 return false; 820 821 if (isa<BreakStmt>(S)) 822 return true; 823 824 // Scan subexpressions for verboten breaks. 825 for (Stmt::const_child_range I = S->children(); I; ++I) 826 if (containsBreak(*I)) 827 return true; 828 829 return false; 830} 831 832 833/// ConstantFoldsToSimpleInteger - If the specified expression does not fold 834/// to a constant, or if it does but contains a label, return false. If it 835/// constant folds return true and set the boolean result in Result. 836bool CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond, 837 bool &ResultBool) { 838 llvm::APSInt ResultInt; 839 if (!ConstantFoldsToSimpleInteger(Cond, ResultInt)) 840 return false; 841 842 ResultBool = ResultInt.getBoolValue(); 843 return true; 844} 845 846/// ConstantFoldsToSimpleInteger - If the specified expression does not fold 847/// to a constant, or if it does but contains a label, return false. If it 848/// constant folds return true and set the folded value. 849bool CodeGenFunction:: 850ConstantFoldsToSimpleInteger(const Expr *Cond, llvm::APSInt &ResultInt) { 851 // FIXME: Rename and handle conversion of other evaluatable things 852 // to bool. 853 llvm::APSInt Int; 854 if (!Cond->EvaluateAsInt(Int, getContext())) 855 return false; // Not foldable, not integer or not fully evaluatable. 856 857 if (CodeGenFunction::ContainsLabel(Cond)) 858 return false; // Contains a label. 859 860 ResultInt = Int; 861 return true; 862} 863 864 865 866/// EmitBranchOnBoolExpr - Emit a branch on a boolean condition (e.g. for an if 867/// statement) to the specified blocks. Based on the condition, this might try 868/// to simplify the codegen of the conditional based on the branch. 869/// 870void CodeGenFunction::EmitBranchOnBoolExpr(const Expr *Cond, 871 llvm::BasicBlock *TrueBlock, 872 llvm::BasicBlock *FalseBlock) { 873 Cond = Cond->IgnoreParens(); 874 875 if (const BinaryOperator *CondBOp = dyn_cast<BinaryOperator>(Cond)) { 876 // Handle X && Y in a condition. 877 if (CondBOp->getOpcode() == BO_LAnd) { 878 // If we have "1 && X", simplify the code. "0 && X" would have constant 879 // folded if the case was simple enough. 880 bool ConstantBool = false; 881 if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) && 882 ConstantBool) { 883 // br(1 && X) -> br(X). 884 return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); 885 } 886 887 // If we have "X && 1", simplify the code to use an uncond branch. 888 // "X && 0" would have been constant folded to 0. 889 if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) && 890 ConstantBool) { 891 // br(X && 1) -> br(X). 892 return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock); 893 } 894 895 // Emit the LHS as a conditional. If the LHS conditional is false, we 896 // want to jump to the FalseBlock. 897 llvm::BasicBlock *LHSTrue = createBasicBlock("land.lhs.true"); 898 899 ConditionalEvaluation eval(*this); 900 EmitBranchOnBoolExpr(CondBOp->getLHS(), LHSTrue, FalseBlock); 901 EmitBlock(LHSTrue); 902 903 // Any temporaries created here are conditional. 904 eval.begin(*this); 905 EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); 906 eval.end(*this); 907 908 return; 909 } 910 911 if (CondBOp->getOpcode() == BO_LOr) { 912 // If we have "0 || X", simplify the code. "1 || X" would have constant 913 // folded if the case was simple enough. 914 bool ConstantBool = false; 915 if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) && 916 !ConstantBool) { 917 // br(0 || X) -> br(X). 918 return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); 919 } 920 921 // If we have "X || 0", simplify the code to use an uncond branch. 922 // "X || 1" would have been constant folded to 1. 923 if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) && 924 !ConstantBool) { 925 // br(X || 0) -> br(X). 926 return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock); 927 } 928 929 // Emit the LHS as a conditional. If the LHS conditional is true, we 930 // want to jump to the TrueBlock. 931 llvm::BasicBlock *LHSFalse = createBasicBlock("lor.lhs.false"); 932 933 ConditionalEvaluation eval(*this); 934 EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, LHSFalse); 935 EmitBlock(LHSFalse); 936 937 // Any temporaries created here are conditional. 938 eval.begin(*this); 939 EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock); 940 eval.end(*this); 941 942 return; 943 } 944 } 945 946 if (const UnaryOperator *CondUOp = dyn_cast<UnaryOperator>(Cond)) { 947 // br(!x, t, f) -> br(x, f, t) 948 if (CondUOp->getOpcode() == UO_LNot) 949 return EmitBranchOnBoolExpr(CondUOp->getSubExpr(), FalseBlock, TrueBlock); 950 } 951 952 if (const ConditionalOperator *CondOp = dyn_cast<ConditionalOperator>(Cond)) { 953 // br(c ? x : y, t, f) -> br(c, br(x, t, f), br(y, t, f)) 954 llvm::BasicBlock *LHSBlock = createBasicBlock("cond.true"); 955 llvm::BasicBlock *RHSBlock = createBasicBlock("cond.false"); 956 957 ConditionalEvaluation cond(*this); 958 EmitBranchOnBoolExpr(CondOp->getCond(), LHSBlock, RHSBlock); 959 960 cond.begin(*this); 961 EmitBlock(LHSBlock); 962 EmitBranchOnBoolExpr(CondOp->getLHS(), TrueBlock, FalseBlock); 963 cond.end(*this); 964 965 cond.begin(*this); 966 EmitBlock(RHSBlock); 967 EmitBranchOnBoolExpr(CondOp->getRHS(), TrueBlock, FalseBlock); 968 cond.end(*this); 969 970 return; 971 } 972 973 if (const CXXThrowExpr *Throw = dyn_cast<CXXThrowExpr>(Cond)) { 974 // Conditional operator handling can give us a throw expression as a 975 // condition for a case like: 976 // br(c ? throw x : y, t, f) -> br(c, br(throw x, t, f), br(y, t, f) 977 // Fold this to: 978 // br(c, throw x, br(y, t, f)) 979 EmitCXXThrowExpr(Throw, /*KeepInsertionPoint*/false); 980 return; 981 } 982 983 // Emit the code with the fully general case. 984 llvm::Value *CondV = EvaluateExprAsBool(Cond); 985 Builder.CreateCondBr(CondV, TrueBlock, FalseBlock); 986} 987 988/// ErrorUnsupported - Print out an error that codegen doesn't support the 989/// specified stmt yet. 990void CodeGenFunction::ErrorUnsupported(const Stmt *S, const char *Type) { 991 CGM.ErrorUnsupported(S, Type); 992} 993 994/// emitNonZeroVLAInit - Emit the "zero" initialization of a 995/// variable-length array whose elements have a non-zero bit-pattern. 996/// 997/// \param baseType the inner-most element type of the array 998/// \param src - a char* pointing to the bit-pattern for a single 999/// base element of the array 1000/// \param sizeInChars - the total size of the VLA, in chars 1001static void emitNonZeroVLAInit(CodeGenFunction &CGF, QualType baseType, 1002 llvm::Value *dest, llvm::Value *src, 1003 llvm::Value *sizeInChars) { 1004 std::pair<CharUnits,CharUnits> baseSizeAndAlign 1005 = CGF.getContext().getTypeInfoInChars(baseType); 1006 1007 CGBuilderTy &Builder = CGF.Builder; 1008 1009 llvm::Value *baseSizeInChars 1010 = llvm::ConstantInt::get(CGF.IntPtrTy, baseSizeAndAlign.first.getQuantity()); 1011 1012 llvm::Type *i8p = Builder.getInt8PtrTy(); 1013 1014 llvm::Value *begin = Builder.CreateBitCast(dest, i8p, "vla.begin"); 1015 llvm::Value *end = Builder.CreateInBoundsGEP(dest, sizeInChars, "vla.end"); 1016 1017 llvm::BasicBlock *originBB = CGF.Builder.GetInsertBlock(); 1018 llvm::BasicBlock *loopBB = CGF.createBasicBlock("vla-init.loop"); 1019 llvm::BasicBlock *contBB = CGF.createBasicBlock("vla-init.cont"); 1020 1021 // Make a loop over the VLA. C99 guarantees that the VLA element 1022 // count must be nonzero. 1023 CGF.EmitBlock(loopBB); 1024 1025 llvm::PHINode *cur = Builder.CreatePHI(i8p, 2, "vla.cur"); 1026 cur->addIncoming(begin, originBB); 1027 1028 // memcpy the individual element bit-pattern. 1029 Builder.CreateMemCpy(cur, src, baseSizeInChars, 1030 baseSizeAndAlign.second.getQuantity(), 1031 /*volatile*/ false); 1032 1033 // Go to the next element. 1034 llvm::Value *next = Builder.CreateConstInBoundsGEP1_32(cur, 1, "vla.next"); 1035 1036 // Leave if that's the end of the VLA. 1037 llvm::Value *done = Builder.CreateICmpEQ(next, end, "vla-init.isdone"); 1038 Builder.CreateCondBr(done, contBB, loopBB); 1039 cur->addIncoming(next, loopBB); 1040 1041 CGF.EmitBlock(contBB); 1042} 1043 1044void 1045CodeGenFunction::EmitNullInitialization(llvm::Value *DestPtr, QualType Ty) { 1046 // Ignore empty classes in C++. 1047 if (getLangOpts().CPlusPlus) { 1048 if (const RecordType *RT = Ty->getAs<RecordType>()) { 1049 if (cast<CXXRecordDecl>(RT->getDecl())->isEmpty()) 1050 return; 1051 } 1052 } 1053 1054 // Cast the dest ptr to the appropriate i8 pointer type. 1055 unsigned DestAS = 1056 cast<llvm::PointerType>(DestPtr->getType())->getAddressSpace(); 1057 llvm::Type *BP = Builder.getInt8PtrTy(DestAS); 1058 if (DestPtr->getType() != BP) 1059 DestPtr = Builder.CreateBitCast(DestPtr, BP); 1060 1061 // Get size and alignment info for this aggregate. 1062 std::pair<CharUnits, CharUnits> TypeInfo = 1063 getContext().getTypeInfoInChars(Ty); 1064 CharUnits Size = TypeInfo.first; 1065 CharUnits Align = TypeInfo.second; 1066 1067 llvm::Value *SizeVal; 1068 const VariableArrayType *vla; 1069 1070 // Don't bother emitting a zero-byte memset. 1071 if (Size.isZero()) { 1072 // But note that getTypeInfo returns 0 for a VLA. 1073 if (const VariableArrayType *vlaType = 1074 dyn_cast_or_null<VariableArrayType>( 1075 getContext().getAsArrayType(Ty))) { 1076 QualType eltType; 1077 llvm::Value *numElts; 1078 llvm::tie(numElts, eltType) = getVLASize(vlaType); 1079 1080 SizeVal = numElts; 1081 CharUnits eltSize = getContext().getTypeSizeInChars(eltType); 1082 if (!eltSize.isOne()) 1083 SizeVal = Builder.CreateNUWMul(SizeVal, CGM.getSize(eltSize)); 1084 vla = vlaType; 1085 } else { 1086 return; 1087 } 1088 } else { 1089 SizeVal = CGM.getSize(Size); 1090 vla = 0; 1091 } 1092 1093 // If the type contains a pointer to data member we can't memset it to zero. 1094 // Instead, create a null constant and copy it to the destination. 1095 // TODO: there are other patterns besides zero that we can usefully memset, 1096 // like -1, which happens to be the pattern used by member-pointers. 1097 if (!CGM.getTypes().isZeroInitializable(Ty)) { 1098 // For a VLA, emit a single element, then splat that over the VLA. 1099 if (vla) Ty = getContext().getBaseElementType(vla); 1100 1101 llvm::Constant *NullConstant = CGM.EmitNullConstant(Ty); 1102 1103 llvm::GlobalVariable *NullVariable = 1104 new llvm::GlobalVariable(CGM.getModule(), NullConstant->getType(), 1105 /*isConstant=*/true, 1106 llvm::GlobalVariable::PrivateLinkage, 1107 NullConstant, Twine()); 1108 llvm::Value *SrcPtr = 1109 Builder.CreateBitCast(NullVariable, Builder.getInt8PtrTy()); 1110 1111 if (vla) return emitNonZeroVLAInit(*this, Ty, DestPtr, SrcPtr, SizeVal); 1112 1113 // Get and call the appropriate llvm.memcpy overload. 1114 Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, Align.getQuantity(), false); 1115 return; 1116 } 1117 1118 // Otherwise, just memset the whole thing to zero. This is legal 1119 // because in LLVM, all default initializers (other than the ones we just 1120 // handled above) are guaranteed to have a bit pattern of all zeros. 1121 Builder.CreateMemSet(DestPtr, Builder.getInt8(0), SizeVal, 1122 Align.getQuantity(), false); 1123} 1124 1125llvm::BlockAddress *CodeGenFunction::GetAddrOfLabel(const LabelDecl *L) { 1126 // Make sure that there is a block for the indirect goto. 1127 if (IndirectBranch == 0) 1128 GetIndirectGotoBlock(); 1129 1130 llvm::BasicBlock *BB = getJumpDestForLabel(L).getBlock(); 1131 1132 // Make sure the indirect branch includes all of the address-taken blocks. 1133 IndirectBranch->addDestination(BB); 1134 return llvm::BlockAddress::get(CurFn, BB); 1135} 1136 1137llvm::BasicBlock *CodeGenFunction::GetIndirectGotoBlock() { 1138 // If we already made the indirect branch for indirect goto, return its block. 1139 if (IndirectBranch) return IndirectBranch->getParent(); 1140 1141 CGBuilderTy TmpBuilder(createBasicBlock("indirectgoto")); 1142 1143 // Create the PHI node that indirect gotos will add entries to. 1144 llvm::Value *DestVal = TmpBuilder.CreatePHI(Int8PtrTy, 0, 1145 "indirect.goto.dest"); 1146 1147 // Create the indirect branch instruction. 1148 IndirectBranch = TmpBuilder.CreateIndirectBr(DestVal); 1149 return IndirectBranch->getParent(); 1150} 1151 1152/// Computes the length of an array in elements, as well as the base 1153/// element type and a properly-typed first element pointer. 1154llvm::Value *CodeGenFunction::emitArrayLength(const ArrayType *origArrayType, 1155 QualType &baseType, 1156 llvm::Value *&addr) { 1157 const ArrayType *arrayType = origArrayType; 1158 1159 // If it's a VLA, we have to load the stored size. Note that 1160 // this is the size of the VLA in bytes, not its size in elements. 1161 llvm::Value *numVLAElements = 0; 1162 if (isa<VariableArrayType>(arrayType)) { 1163 numVLAElements = getVLASize(cast<VariableArrayType>(arrayType)).first; 1164 1165 // Walk into all VLAs. This doesn't require changes to addr, 1166 // which has type T* where T is the first non-VLA element type. 1167 do { 1168 QualType elementType = arrayType->getElementType(); 1169 arrayType = getContext().getAsArrayType(elementType); 1170 1171 // If we only have VLA components, 'addr' requires no adjustment. 1172 if (!arrayType) { 1173 baseType = elementType; 1174 return numVLAElements; 1175 } 1176 } while (isa<VariableArrayType>(arrayType)); 1177 1178 // We get out here only if we find a constant array type 1179 // inside the VLA. 1180 } 1181 1182 // We have some number of constant-length arrays, so addr should 1183 // have LLVM type [M x [N x [...]]]*. Build a GEP that walks 1184 // down to the first element of addr. 1185 SmallVector<llvm::Value*, 8> gepIndices; 1186 1187 // GEP down to the array type. 1188 llvm::ConstantInt *zero = Builder.getInt32(0); 1189 gepIndices.push_back(zero); 1190 1191 uint64_t countFromCLAs = 1; 1192 QualType eltType; 1193 1194 llvm::ArrayType *llvmArrayType = 1195 dyn_cast<llvm::ArrayType>( 1196 cast<llvm::PointerType>(addr->getType())->getElementType()); 1197 while (llvmArrayType) { 1198 assert(isa<ConstantArrayType>(arrayType)); 1199 assert(cast<ConstantArrayType>(arrayType)->getSize().getZExtValue() 1200 == llvmArrayType->getNumElements()); 1201 1202 gepIndices.push_back(zero); 1203 countFromCLAs *= llvmArrayType->getNumElements(); 1204 eltType = arrayType->getElementType(); 1205 1206 llvmArrayType = 1207 dyn_cast<llvm::ArrayType>(llvmArrayType->getElementType()); 1208 arrayType = getContext().getAsArrayType(arrayType->getElementType()); 1209 assert((!llvmArrayType || arrayType) && 1210 "LLVM and Clang types are out-of-synch"); 1211 } 1212 1213 if (arrayType) { 1214 // From this point onwards, the Clang array type has been emitted 1215 // as some other type (probably a packed struct). Compute the array 1216 // size, and just emit the 'begin' expression as a bitcast. 1217 while (arrayType) { 1218 countFromCLAs *= 1219 cast<ConstantArrayType>(arrayType)->getSize().getZExtValue(); 1220 eltType = arrayType->getElementType(); 1221 arrayType = getContext().getAsArrayType(eltType); 1222 } 1223 1224 unsigned AddressSpace = addr->getType()->getPointerAddressSpace(); 1225 llvm::Type *BaseType = ConvertType(eltType)->getPointerTo(AddressSpace); 1226 addr = Builder.CreateBitCast(addr, BaseType, "array.begin"); 1227 } else { 1228 // Create the actual GEP. 1229 addr = Builder.CreateInBoundsGEP(addr, gepIndices, "array.begin"); 1230 } 1231 1232 baseType = eltType; 1233 1234 llvm::Value *numElements 1235 = llvm::ConstantInt::get(SizeTy, countFromCLAs); 1236 1237 // If we had any VLA dimensions, factor them in. 1238 if (numVLAElements) 1239 numElements = Builder.CreateNUWMul(numVLAElements, numElements); 1240 1241 return numElements; 1242} 1243 1244std::pair<llvm::Value*, QualType> 1245CodeGenFunction::getVLASize(QualType type) { 1246 const VariableArrayType *vla = getContext().getAsVariableArrayType(type); 1247 assert(vla && "type was not a variable array type!"); 1248 return getVLASize(vla); 1249} 1250 1251std::pair<llvm::Value*, QualType> 1252CodeGenFunction::getVLASize(const VariableArrayType *type) { 1253 // The number of elements so far; always size_t. 1254 llvm::Value *numElements = 0; 1255 1256 QualType elementType; 1257 do { 1258 elementType = type->getElementType(); 1259 llvm::Value *vlaSize = VLASizeMap[type->getSizeExpr()]; 1260 assert(vlaSize && "no size for VLA!"); 1261 assert(vlaSize->getType() == SizeTy); 1262 1263 if (!numElements) { 1264 numElements = vlaSize; 1265 } else { 1266 // It's undefined behavior if this wraps around, so mark it that way. 1267 // FIXME: Teach -fcatch-undefined-behavior to trap this. 1268 numElements = Builder.CreateNUWMul(numElements, vlaSize); 1269 } 1270 } while ((type = getContext().getAsVariableArrayType(elementType))); 1271 1272 return std::pair<llvm::Value*,QualType>(numElements, elementType); 1273} 1274 1275void CodeGenFunction::EmitVariablyModifiedType(QualType type) { 1276 assert(type->isVariablyModifiedType() && 1277 "Must pass variably modified type to EmitVLASizes!"); 1278 1279 EnsureInsertPoint(); 1280 1281 // We're going to walk down into the type and look for VLA 1282 // expressions. 1283 do { 1284 assert(type->isVariablyModifiedType()); 1285 1286 const Type *ty = type.getTypePtr(); 1287 switch (ty->getTypeClass()) { 1288 1289#define TYPE(Class, Base) 1290#define ABSTRACT_TYPE(Class, Base) 1291#define NON_CANONICAL_TYPE(Class, Base) 1292#define DEPENDENT_TYPE(Class, Base) case Type::Class: 1293#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) 1294#include "clang/AST/TypeNodes.def" 1295 llvm_unreachable("unexpected dependent type!"); 1296 1297 // These types are never variably-modified. 1298 case Type::Builtin: 1299 case Type::Complex: 1300 case Type::Vector: 1301 case Type::ExtVector: 1302 case Type::Record: 1303 case Type::Enum: 1304 case Type::Elaborated: 1305 case Type::TemplateSpecialization: 1306 case Type::ObjCObject: 1307 case Type::ObjCInterface: 1308 case Type::ObjCObjectPointer: 1309 llvm_unreachable("type class is never variably-modified!"); 1310 1311 case Type::Decayed: 1312 type = cast<DecayedType>(ty)->getPointeeType(); 1313 break; 1314 1315 case Type::Pointer: 1316 type = cast<PointerType>(ty)->getPointeeType(); 1317 break; 1318 1319 case Type::BlockPointer: 1320 type = cast<BlockPointerType>(ty)->getPointeeType(); 1321 break; 1322 1323 case Type::LValueReference: 1324 case Type::RValueReference: 1325 type = cast<ReferenceType>(ty)->getPointeeType(); 1326 break; 1327 1328 case Type::MemberPointer: 1329 type = cast<MemberPointerType>(ty)->getPointeeType(); 1330 break; 1331 1332 case Type::ConstantArray: 1333 case Type::IncompleteArray: 1334 // Losing element qualification here is fine. 1335 type = cast<ArrayType>(ty)->getElementType(); 1336 break; 1337 1338 case Type::VariableArray: { 1339 // Losing element qualification here is fine. 1340 const VariableArrayType *vat = cast<VariableArrayType>(ty); 1341 1342 // Unknown size indication requires no size computation. 1343 // Otherwise, evaluate and record it. 1344 if (const Expr *size = vat->getSizeExpr()) { 1345 // It's possible that we might have emitted this already, 1346 // e.g. with a typedef and a pointer to it. 1347 llvm::Value *&entry = VLASizeMap[size]; 1348 if (!entry) { 1349 llvm::Value *Size = EmitScalarExpr(size); 1350 1351 // C11 6.7.6.2p5: 1352 // If the size is an expression that is not an integer constant 1353 // expression [...] each time it is evaluated it shall have a value 1354 // greater than zero. 1355 if (SanOpts->VLABound && 1356 size->getType()->isSignedIntegerType()) { 1357 llvm::Value *Zero = llvm::Constant::getNullValue(Size->getType()); 1358 llvm::Constant *StaticArgs[] = { 1359 EmitCheckSourceLocation(size->getLocStart()), 1360 EmitCheckTypeDescriptor(size->getType()) 1361 }; 1362 EmitCheck(Builder.CreateICmpSGT(Size, Zero), 1363 "vla_bound_not_positive", StaticArgs, Size, 1364 CRK_Recoverable); 1365 } 1366 1367 // Always zexting here would be wrong if it weren't 1368 // undefined behavior to have a negative bound. 1369 entry = Builder.CreateIntCast(Size, SizeTy, /*signed*/ false); 1370 } 1371 } 1372 type = vat->getElementType(); 1373 break; 1374 } 1375 1376 case Type::FunctionProto: 1377 case Type::FunctionNoProto: 1378 type = cast<FunctionType>(ty)->getResultType(); 1379 break; 1380 1381 case Type::Paren: 1382 case Type::TypeOf: 1383 case Type::UnaryTransform: 1384 case Type::Attributed: 1385 case Type::SubstTemplateTypeParm: 1386 case Type::PackExpansion: 1387 // Keep walking after single level desugaring. 1388 type = type.getSingleStepDesugaredType(getContext()); 1389 break; 1390 1391 case Type::Typedef: 1392 case Type::Decltype: 1393 case Type::Auto: 1394 // Stop walking: nothing to do. 1395 return; 1396 1397 case Type::TypeOfExpr: 1398 // Stop walking: emit typeof expression. 1399 EmitIgnoredExpr(cast<TypeOfExprType>(ty)->getUnderlyingExpr()); 1400 return; 1401 1402 case Type::Atomic: 1403 type = cast<AtomicType>(ty)->getValueType(); 1404 break; 1405 } 1406 } while (type->isVariablyModifiedType()); 1407} 1408 1409llvm::Value* CodeGenFunction::EmitVAListRef(const Expr* E) { 1410 if (getContext().getBuiltinVaListType()->isArrayType()) 1411 return EmitScalarExpr(E); 1412 return EmitLValue(E).getAddress(); 1413} 1414 1415void CodeGenFunction::EmitDeclRefExprDbgValue(const DeclRefExpr *E, 1416 llvm::Constant *Init) { 1417 assert (Init && "Invalid DeclRefExpr initializer!"); 1418 if (CGDebugInfo *Dbg = getDebugInfo()) 1419 if (CGM.getCodeGenOpts().getDebugInfo() >= CodeGenOptions::LimitedDebugInfo) 1420 Dbg->EmitGlobalVariable(E->getDecl(), Init); 1421} 1422 1423CodeGenFunction::PeepholeProtection 1424CodeGenFunction::protectFromPeepholes(RValue rvalue) { 1425 // At the moment, the only aggressive peephole we do in IR gen 1426 // is trunc(zext) folding, but if we add more, we can easily 1427 // extend this protection. 1428 1429 if (!rvalue.isScalar()) return PeepholeProtection(); 1430 llvm::Value *value = rvalue.getScalarVal(); 1431 if (!isa<llvm::ZExtInst>(value)) return PeepholeProtection(); 1432 1433 // Just make an extra bitcast. 1434 assert(HaveInsertPoint()); 1435 llvm::Instruction *inst = new llvm::BitCastInst(value, value->getType(), "", 1436 Builder.GetInsertBlock()); 1437 1438 PeepholeProtection protection; 1439 protection.Inst = inst; 1440 return protection; 1441} 1442 1443void CodeGenFunction::unprotectFromPeepholes(PeepholeProtection protection) { 1444 if (!protection.Inst) return; 1445 1446 // In theory, we could try to duplicate the peepholes now, but whatever. 1447 protection.Inst->eraseFromParent(); 1448} 1449 1450llvm::Value *CodeGenFunction::EmitAnnotationCall(llvm::Value *AnnotationFn, 1451 llvm::Value *AnnotatedVal, 1452 StringRef AnnotationStr, 1453 SourceLocation Location) { 1454 llvm::Value *Args[4] = { 1455 AnnotatedVal, 1456 Builder.CreateBitCast(CGM.EmitAnnotationString(AnnotationStr), Int8PtrTy), 1457 Builder.CreateBitCast(CGM.EmitAnnotationUnit(Location), Int8PtrTy), 1458 CGM.EmitAnnotationLineNo(Location) 1459 }; 1460 return Builder.CreateCall(AnnotationFn, Args); 1461} 1462 1463void CodeGenFunction::EmitVarAnnotations(const VarDecl *D, llvm::Value *V) { 1464 assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute"); 1465 // FIXME We create a new bitcast for every annotation because that's what 1466 // llvm-gcc was doing. 1467 for (specific_attr_iterator<AnnotateAttr> 1468 ai = D->specific_attr_begin<AnnotateAttr>(), 1469 ae = D->specific_attr_end<AnnotateAttr>(); ai != ae; ++ai) 1470 EmitAnnotationCall(CGM.getIntrinsic(llvm::Intrinsic::var_annotation), 1471 Builder.CreateBitCast(V, CGM.Int8PtrTy, V->getName()), 1472 (*ai)->getAnnotation(), D->getLocation()); 1473} 1474 1475llvm::Value *CodeGenFunction::EmitFieldAnnotations(const FieldDecl *D, 1476 llvm::Value *V) { 1477 assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute"); 1478 llvm::Type *VTy = V->getType(); 1479 llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::ptr_annotation, 1480 CGM.Int8PtrTy); 1481 1482 for (specific_attr_iterator<AnnotateAttr> 1483 ai = D->specific_attr_begin<AnnotateAttr>(), 1484 ae = D->specific_attr_end<AnnotateAttr>(); ai != ae; ++ai) { 1485 // FIXME Always emit the cast inst so we can differentiate between 1486 // annotation on the first field of a struct and annotation on the struct 1487 // itself. 1488 if (VTy != CGM.Int8PtrTy) 1489 V = Builder.Insert(new llvm::BitCastInst(V, CGM.Int8PtrTy)); 1490 V = EmitAnnotationCall(F, V, (*ai)->getAnnotation(), D->getLocation()); 1491 V = Builder.CreateBitCast(V, VTy); 1492 } 1493 1494 return V; 1495} 1496 1497CodeGenFunction::CGCapturedStmtInfo::~CGCapturedStmtInfo() { } 1498