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CodeGenFunction.cpp
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//===--- CodeGenFunction.cpp - Emit LLVM Code from ASTs for a Function ----===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This coordinates the per-function state used while generating code.
//
//===----------------------------------------------------------------------===//
#include "CodeGenFunction.h"
#include "CGCUDARuntime.h"
#include "CGCXXABI.h"
#include "CGDebugInfo.h"
#include "CodeGenModule.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/StmtCXX.h"
#include "clang/Basic/OpenCL.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Frontend/CodeGenOptions.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Operator.h"
using namespace clang;
using namespace CodeGen;
CodeGenFunction::CodeGenFunction(CodeGenModule &cgm, bool suppressNewContext)
: CodeGenTypeCache(cgm), CGM(cgm), Target(cgm.getTarget()),
Builder(cgm.getModule().getContext()),
CapturedStmtInfo(0),
SanitizePerformTypeCheck(CGM.getSanOpts().Null |
CGM.getSanOpts().Alignment |
CGM.getSanOpts().ObjectSize |
CGM.getSanOpts().Vptr),
SanOpts(&CGM.getSanOpts()),
AutoreleaseResult(false), BlockInfo(0), BlockPointer(0),
LambdaThisCaptureField(0), NormalCleanupDest(0), NextCleanupDestIndex(1),
FirstBlockInfo(0), EHResumeBlock(0), ExceptionSlot(0), EHSelectorSlot(0),
DebugInfo(0), DisableDebugInfo(false), DidCallStackSave(false),
IndirectBranch(0), SwitchInsn(0), CaseRangeBlock(0), UnreachableBlock(0),
NumReturnExprs(0), NumSimpleReturnExprs(0),
CXXABIThisDecl(0), CXXABIThisValue(0), CXXThisValue(0),
CXXDefaultInitExprThis(0),
CXXStructorImplicitParamDecl(0), CXXStructorImplicitParamValue(0),
OutermostConditional(0), CurLexicalScope(0), TerminateLandingPad(0),
TerminateHandler(0), TrapBB(0) {
if (!suppressNewContext)
CGM.getCXXABI().getMangleContext().startNewFunction();
llvm::FastMathFlags FMF;
if (CGM.getLangOpts().FastMath)
FMF.setUnsafeAlgebra();
if (CGM.getLangOpts().FiniteMathOnly) {
FMF.setNoNaNs();
FMF.setNoInfs();
}
Builder.SetFastMathFlags(FMF);
}
CodeGenFunction::~CodeGenFunction() {
assert(LifetimeExtendedCleanupStack.empty() && "failed to emit a cleanup");
// If there are any unclaimed block infos, go ahead and destroy them
// now. This can happen if IR-gen gets clever and skips evaluating
// something.
if (FirstBlockInfo)
destroyBlockInfos(FirstBlockInfo);
}
llvm::Type *CodeGenFunction::ConvertTypeForMem(QualType T) {
return CGM.getTypes().ConvertTypeForMem(T);
}
llvm::Type *CodeGenFunction::ConvertType(QualType T) {
return CGM.getTypes().ConvertType(T);
}
TypeEvaluationKind CodeGenFunction::getEvaluationKind(QualType type) {
type = type.getCanonicalType();
while (true) {
switch (type->getTypeClass()) {
#define TYPE(name, parent)
#define ABSTRACT_TYPE(name, parent)
#define NON_CANONICAL_TYPE(name, parent) case Type::name:
#define DEPENDENT_TYPE(name, parent) case Type::name:
#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(name, parent) case Type::name:
#include "clang/AST/TypeNodes.def"
llvm_unreachable("non-canonical or dependent type in IR-generation");
case Type::Auto:
llvm_unreachable("undeduced auto type in IR-generation");
// Various scalar types.
case Type::Builtin:
case Type::Pointer:
case Type::BlockPointer:
case Type::LValueReference:
case Type::RValueReference:
case Type::MemberPointer:
case Type::Vector:
case Type::ExtVector:
case Type::FunctionProto:
case Type::FunctionNoProto:
case Type::Enum:
case Type::ObjCObjectPointer:
return TEK_Scalar;
// Complexes.
case Type::Complex:
return TEK_Complex;
// Arrays, records, and Objective-C objects.
case Type::ConstantArray:
case Type::IncompleteArray:
case Type::VariableArray:
case Type::Record:
case Type::ObjCObject:
case Type::ObjCInterface:
return TEK_Aggregate;
// We operate on atomic values according to their underlying type.
case Type::Atomic:
type = cast<AtomicType>(type)->getValueType();
continue;
}
llvm_unreachable("unknown type kind!");
}
}
void CodeGenFunction::EmitReturnBlock() {
// For cleanliness, we try to avoid emitting the return block for
// simple cases.
llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
if (CurBB) {
assert(!CurBB->getTerminator() && "Unexpected terminated block.");
// We have a valid insert point, reuse it if it is empty or there are no
// explicit jumps to the return block.
if (CurBB->empty() || ReturnBlock.getBlock()->use_empty()) {
ReturnBlock.getBlock()->replaceAllUsesWith(CurBB);
delete ReturnBlock.getBlock();
} else
EmitBlock(ReturnBlock.getBlock());
return;
}
// Otherwise, if the return block is the target of a single direct
// branch then we can just put the code in that block instead. This
// cleans up functions which started with a unified return block.
if (ReturnBlock.getBlock()->hasOneUse()) {
llvm::BranchInst *BI =
dyn_cast<llvm::BranchInst>(*ReturnBlock.getBlock()->use_begin());
if (BI && BI->isUnconditional() &&
BI->getSuccessor(0) == ReturnBlock.getBlock()) {
// Reset insertion point, including debug location, and delete the
// branch. This is really subtle and only works because the next change
// in location will hit the caching in CGDebugInfo::EmitLocation and not
// override this.
Builder.SetCurrentDebugLocation(BI->getDebugLoc());
Builder.SetInsertPoint(BI->getParent());
BI->eraseFromParent();
delete ReturnBlock.getBlock();
return;
}
}
// FIXME: We are at an unreachable point, there is no reason to emit the block
// unless it has uses. However, we still need a place to put the debug
// region.end for now.
EmitBlock(ReturnBlock.getBlock());
}
static void EmitIfUsed(CodeGenFunction &CGF, llvm::BasicBlock *BB) {
if (!BB) return;
if (!BB->use_empty())
return CGF.CurFn->getBasicBlockList().push_back(BB);
delete BB;
}
void CodeGenFunction::FinishFunction(SourceLocation EndLoc) {
assert(BreakContinueStack.empty() &&
"mismatched push/pop in break/continue stack!");
bool OnlySimpleReturnStmts = NumSimpleReturnExprs > 0
&& NumSimpleReturnExprs == NumReturnExprs
&& ReturnBlock.getBlock()->use_empty();
// Usually the return expression is evaluated before the cleanup
// code. If the function contains only a simple return statement,
// such as a constant, the location before the cleanup code becomes
// the last useful breakpoint in the function, because the simple
// return expression will be evaluated after the cleanup code. To be
// safe, set the debug location for cleanup code to the location of
// the return statement. Otherwise the cleanup code should be at the
// end of the function's lexical scope.
//
// If there are multiple branches to the return block, the branch
// instructions will get the location of the return statements and
// all will be fine.
if (CGDebugInfo *DI = getDebugInfo()) {
if (OnlySimpleReturnStmts)
DI->EmitLocation(Builder, LastStopPoint);
else
DI->EmitLocation(Builder, EndLoc);
}
// Pop any cleanups that might have been associated with the
// parameters. Do this in whatever block we're currently in; it's
// important to do this before we enter the return block or return
// edges will be *really* confused.
bool EmitRetDbgLoc = true;
if (EHStack.stable_begin() != PrologueCleanupDepth) {
PopCleanupBlocks(PrologueCleanupDepth);
// Make sure the line table doesn't jump back into the body for
// the ret after it's been at EndLoc.
EmitRetDbgLoc = false;
if (CGDebugInfo *DI = getDebugInfo())
if (OnlySimpleReturnStmts)
DI->EmitLocation(Builder, EndLoc);
}
// Emit function epilog (to return).
EmitReturnBlock();
if (ShouldInstrumentFunction())
EmitFunctionInstrumentation("__cyg_profile_func_exit");
// Emit debug descriptor for function end.
if (CGDebugInfo *DI = getDebugInfo()) {
DI->EmitFunctionEnd(Builder);
}
EmitFunctionEpilog(*CurFnInfo, EmitRetDbgLoc);
EmitEndEHSpec(CurCodeDecl);
assert(EHStack.empty() &&
"did not remove all scopes from cleanup stack!");
// If someone did an indirect goto, emit the indirect goto block at the end of
// the function.
if (IndirectBranch) {
EmitBlock(IndirectBranch->getParent());
Builder.ClearInsertionPoint();
}
// Remove the AllocaInsertPt instruction, which is just a convenience for us.
llvm::Instruction *Ptr = AllocaInsertPt;
AllocaInsertPt = 0;
Ptr->eraseFromParent();
// If someone took the address of a label but never did an indirect goto, we
// made a zero entry PHI node, which is illegal, zap it now.
if (IndirectBranch) {
llvm::PHINode *PN = cast<llvm::PHINode>(IndirectBranch->getAddress());
if (PN->getNumIncomingValues() == 0) {
PN->replaceAllUsesWith(llvm::UndefValue::get(PN->getType()));
PN->eraseFromParent();
}
}
EmitIfUsed(*this, EHResumeBlock);
EmitIfUsed(*this, TerminateLandingPad);
EmitIfUsed(*this, TerminateHandler);
EmitIfUsed(*this, UnreachableBlock);
if (CGM.getCodeGenOpts().EmitDeclMetadata)
EmitDeclMetadata();
}
/// ShouldInstrumentFunction - Return true if the current function should be
/// instrumented with __cyg_profile_func_* calls
bool CodeGenFunction::ShouldInstrumentFunction() {
if (!CGM.getCodeGenOpts().InstrumentFunctions)
return false;
if (!CurFuncDecl || CurFuncDecl->hasAttr<NoInstrumentFunctionAttr>())
return false;
return true;
}
/// EmitFunctionInstrumentation - Emit LLVM code to call the specified
/// instrumentation function with the current function and the call site, if
/// function instrumentation is enabled.
void CodeGenFunction::EmitFunctionInstrumentation(const char *Fn) {
// void __cyg_profile_func_{enter,exit} (void *this_fn, void *call_site);
llvm::PointerType *PointerTy = Int8PtrTy;
llvm::Type *ProfileFuncArgs[] = { PointerTy, PointerTy };
llvm::FunctionType *FunctionTy =
llvm::FunctionType::get(VoidTy, ProfileFuncArgs, false);
llvm::Constant *F = CGM.CreateRuntimeFunction(FunctionTy, Fn);
llvm::CallInst *CallSite = Builder.CreateCall(
CGM.getIntrinsic(llvm::Intrinsic::returnaddress),
llvm::ConstantInt::get(Int32Ty, 0),
"callsite");
llvm::Value *args[] = {
llvm::ConstantExpr::getBitCast(CurFn, PointerTy),
CallSite
};
EmitNounwindRuntimeCall(F, args);
}
void CodeGenFunction::EmitMCountInstrumentation() {
llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
llvm::Constant *MCountFn =
CGM.CreateRuntimeFunction(FTy, getTarget().getMCountName());
EmitNounwindRuntimeCall(MCountFn);
}
// OpenCL v1.2 s5.6.4.6 allows the compiler to store kernel argument
// information in the program executable. The argument information stored
// includes the argument name, its type, the address and access qualifiers used.
static void GenOpenCLArgMetadata(const FunctionDecl *FD, llvm::Function *Fn,
CodeGenModule &CGM,llvm::LLVMContext &Context,
SmallVector <llvm::Value*, 5> &kernelMDArgs,
CGBuilderTy& Builder, ASTContext &ASTCtx) {
// Create MDNodes that represent the kernel arg metadata.
// Each MDNode is a list in the form of "key", N number of values which is
// the same number of values as their are kernel arguments.
// MDNode for the kernel argument address space qualifiers.
SmallVector<llvm::Value*, 8> addressQuals;
addressQuals.push_back(llvm::MDString::get(Context, "kernel_arg_addr_space"));
// MDNode for the kernel argument access qualifiers (images only).
SmallVector<llvm::Value*, 8> accessQuals;
accessQuals.push_back(llvm::MDString::get(Context, "kernel_arg_access_qual"));
// MDNode for the kernel argument type names.
SmallVector<llvm::Value*, 8> argTypeNames;
argTypeNames.push_back(llvm::MDString::get(Context, "kernel_arg_type"));
// MDNode for the kernel argument type qualifiers.
SmallVector<llvm::Value*, 8> argTypeQuals;
argTypeQuals.push_back(llvm::MDString::get(Context, "kernel_arg_type_qual"));
// MDNode for the kernel argument names.
SmallVector<llvm::Value*, 8> argNames;
argNames.push_back(llvm::MDString::get(Context, "kernel_arg_name"));
for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i) {
const ParmVarDecl *parm = FD->getParamDecl(i);
QualType ty = parm->getType();
std::string typeQuals;
if (ty->isPointerType()) {
QualType pointeeTy = ty->getPointeeType();
// Get address qualifier.
addressQuals.push_back(Builder.getInt32(ASTCtx.getTargetAddressSpace(
pointeeTy.getAddressSpace())));
// Get argument type name.
std::string typeName = pointeeTy.getUnqualifiedType().getAsString() + "*";
// Turn "unsigned type" to "utype"
std::string::size_type pos = typeName.find("unsigned");
if (pos != std::string::npos)
typeName.erase(pos+1, 8);
argTypeNames.push_back(llvm::MDString::get(Context, typeName));
// Get argument type qualifiers:
if (ty.isRestrictQualified())
typeQuals = "restrict";
if (pointeeTy.isConstQualified() ||
(pointeeTy.getAddressSpace() == LangAS::opencl_constant))
typeQuals += typeQuals.empty() ? "const" : " const";
if (pointeeTy.isVolatileQualified())
typeQuals += typeQuals.empty() ? "volatile" : " volatile";
} else {
addressQuals.push_back(Builder.getInt32(0));
// Get argument type name.
std::string typeName = ty.getUnqualifiedType().getAsString();
// Turn "unsigned type" to "utype"
std::string::size_type pos = typeName.find("unsigned");
if (pos != std::string::npos)
typeName.erase(pos+1, 8);
argTypeNames.push_back(llvm::MDString::get(Context, typeName));
// Get argument type qualifiers:
if (ty.isConstQualified())
typeQuals = "const";
if (ty.isVolatileQualified())
typeQuals += typeQuals.empty() ? "volatile" : " volatile";
}
argTypeQuals.push_back(llvm::MDString::get(Context, typeQuals));
// Get image access qualifier:
if (ty->isImageType()) {
if (parm->hasAttr<OpenCLImageAccessAttr>() &&
parm->getAttr<OpenCLImageAccessAttr>()->getAccess() == CLIA_write_only)
accessQuals.push_back(llvm::MDString::get(Context, "write_only"));
else
accessQuals.push_back(llvm::MDString::get(Context, "read_only"));
} else
accessQuals.push_back(llvm::MDString::get(Context, "none"));
// Get argument name.
argNames.push_back(llvm::MDString::get(Context, parm->getName()));
}
kernelMDArgs.push_back(llvm::MDNode::get(Context, addressQuals));
kernelMDArgs.push_back(llvm::MDNode::get(Context, accessQuals));
kernelMDArgs.push_back(llvm::MDNode::get(Context, argTypeNames));
kernelMDArgs.push_back(llvm::MDNode::get(Context, argTypeQuals));
kernelMDArgs.push_back(llvm::MDNode::get(Context, argNames));
}
void CodeGenFunction::EmitOpenCLKernelMetadata(const FunctionDecl *FD,
llvm::Function *Fn)
{
if (!FD->hasAttr<OpenCLKernelAttr>())
return;
llvm::LLVMContext &Context = getLLVMContext();
SmallVector <llvm::Value*, 5> kernelMDArgs;
kernelMDArgs.push_back(Fn);
if (CGM.getCodeGenOpts().EmitOpenCLArgMetadata)
GenOpenCLArgMetadata(FD, Fn, CGM, Context, kernelMDArgs,
Builder, getContext());
if (FD->hasAttr<VecTypeHintAttr>()) {
VecTypeHintAttr *attr = FD->getAttr<VecTypeHintAttr>();
QualType hintQTy = attr->getTypeHint();
const ExtVectorType *hintEltQTy = hintQTy->getAs<ExtVectorType>();
bool isSignedInteger =
hintQTy->isSignedIntegerType() ||
(hintEltQTy && hintEltQTy->getElementType()->isSignedIntegerType());
llvm::Value *attrMDArgs[] = {
llvm::MDString::get(Context, "vec_type_hint"),
llvm::UndefValue::get(CGM.getTypes().ConvertType(attr->getTypeHint())),
llvm::ConstantInt::get(
llvm::IntegerType::get(Context, 32),
llvm::APInt(32, (uint64_t)(isSignedInteger ? 1 : 0)))
};
kernelMDArgs.push_back(llvm::MDNode::get(Context, attrMDArgs));
}
if (FD->hasAttr<WorkGroupSizeHintAttr>()) {
WorkGroupSizeHintAttr *attr = FD->getAttr<WorkGroupSizeHintAttr>();
llvm::Value *attrMDArgs[] = {
llvm::MDString::get(Context, "work_group_size_hint"),
Builder.getInt32(attr->getXDim()),
Builder.getInt32(attr->getYDim()),
Builder.getInt32(attr->getZDim())
};
kernelMDArgs.push_back(llvm::MDNode::get(Context, attrMDArgs));
}
if (FD->hasAttr<ReqdWorkGroupSizeAttr>()) {
ReqdWorkGroupSizeAttr *attr = FD->getAttr<ReqdWorkGroupSizeAttr>();
llvm::Value *attrMDArgs[] = {
llvm::MDString::get(Context, "reqd_work_group_size"),
Builder.getInt32(attr->getXDim()),
Builder.getInt32(attr->getYDim()),
Builder.getInt32(attr->getZDim())
};
kernelMDArgs.push_back(llvm::MDNode::get(Context, attrMDArgs));
}
llvm::MDNode *kernelMDNode = llvm::MDNode::get(Context, kernelMDArgs);
llvm::NamedMDNode *OpenCLKernelMetadata =
CGM.getModule().getOrInsertNamedMetadata("opencl.kernels");
OpenCLKernelMetadata->addOperand(kernelMDNode);
}
void CodeGenFunction::StartFunction(GlobalDecl GD,
QualType RetTy,
llvm::Function *Fn,
const CGFunctionInfo &FnInfo,
const FunctionArgList &Args,
SourceLocation StartLoc) {
const Decl *D = GD.getDecl();
DidCallStackSave = false;
CurCodeDecl = D;
CurFuncDecl = (D ? D->getNonClosureContext() : 0);
FnRetTy = RetTy;
CurFn = Fn;
CurFnInfo = &FnInfo;
assert(CurFn->isDeclaration() && "Function already has body?");
if (CGM.getSanitizerBlacklist().isIn(*Fn)) {
SanOpts = &SanitizerOptions::Disabled;
SanitizePerformTypeCheck = false;
}
// Pass inline keyword to optimizer if it appears explicitly on any
// declaration.
if (!CGM.getCodeGenOpts().NoInline)
if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D))
for (FunctionDecl::redecl_iterator RI = FD->redecls_begin(),
RE = FD->redecls_end(); RI != RE; ++RI)
if (RI->isInlineSpecified()) {
Fn->addFnAttr(llvm::Attribute::InlineHint);
break;
}
if (getLangOpts().OpenCL) {
// Add metadata for a kernel function.
if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D))
EmitOpenCLKernelMetadata(FD, Fn);
}
llvm::BasicBlock *EntryBB = createBasicBlock("entry", CurFn);
// Create a marker to make it easy to insert allocas into the entryblock
// later. Don't create this with the builder, because we don't want it
// folded.
llvm::Value *Undef = llvm::UndefValue::get(Int32Ty);
AllocaInsertPt = new llvm::BitCastInst(Undef, Int32Ty, "", EntryBB);
if (Builder.isNamePreserving())
AllocaInsertPt->setName("allocapt");
ReturnBlock = getJumpDestInCurrentScope("return");
Builder.SetInsertPoint(EntryBB);
// Emit subprogram debug descriptor.
if (CGDebugInfo *DI = getDebugInfo()) {
SmallVector<QualType, 16> ArgTypes;
for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end();
i != e; ++i) {
ArgTypes.push_back((*i)->getType());
}
QualType FnType =
getContext().getFunctionType(RetTy, ArgTypes,
FunctionProtoType::ExtProtoInfo());
DI->setLocation(StartLoc);
DI->EmitFunctionStart(GD, FnType, CurFn, Builder);
}
if (ShouldInstrumentFunction())
EmitFunctionInstrumentation("__cyg_profile_func_enter");
if (CGM.getCodeGenOpts().InstrumentForProfiling)
EmitMCountInstrumentation();
if (RetTy->isVoidType()) {
// Void type; nothing to return.
ReturnValue = 0;
} else if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::Indirect &&
!hasScalarEvaluationKind(CurFnInfo->getReturnType())) {
// Indirect aggregate return; emit returned value directly into sret slot.
// This reduces code size, and affects correctness in C++.
ReturnValue = CurFn->arg_begin();
} else {
ReturnValue = CreateIRTemp(RetTy, "retval");
// Tell the epilog emitter to autorelease the result. We do this
// now so that various specialized functions can suppress it
// during their IR-generation.
if (getLangOpts().ObjCAutoRefCount &&
!CurFnInfo->isReturnsRetained() &&
RetTy->isObjCRetainableType())
AutoreleaseResult = true;
}
EmitStartEHSpec(CurCodeDecl);
PrologueCleanupDepth = EHStack.stable_begin();
EmitFunctionProlog(*CurFnInfo, CurFn, Args);
if (D && isa<CXXMethodDecl>(D) && cast<CXXMethodDecl>(D)->isInstance()) {
CGM.getCXXABI().EmitInstanceFunctionProlog(*this);
const CXXMethodDecl *MD = cast<CXXMethodDecl>(D);
if (MD->getParent()->isLambda() &&
MD->getOverloadedOperator() == OO_Call) {
// We're in a lambda; figure out the captures.
MD->getParent()->getCaptureFields(LambdaCaptureFields,
LambdaThisCaptureField);
if (LambdaThisCaptureField) {
// If this lambda captures this, load it.
LValue ThisLValue = EmitLValueForLambdaField(LambdaThisCaptureField);
CXXThisValue = EmitLoadOfLValue(ThisLValue).getScalarVal();
}
} else {
// Not in a lambda; just use 'this' from the method.
// FIXME: Should we generate a new load for each use of 'this'? The
// fast register allocator would be happier...
CXXThisValue = CXXABIThisValue;
}
}
// If any of the arguments have a variably modified type, make sure to
// emit the type size.
for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end();
i != e; ++i) {
const VarDecl *VD = *i;
// Dig out the type as written from ParmVarDecls; it's unclear whether
// the standard (C99 6.9.1p10) requires this, but we're following the
// precedent set by gcc.
QualType Ty;
if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(VD))
Ty = PVD->getOriginalType();
else
Ty = VD->getType();
if (Ty->isVariablyModifiedType())
EmitVariablyModifiedType(Ty);
}
// Emit a location at the end of the prologue.
if (CGDebugInfo *DI = getDebugInfo())
DI->EmitLocation(Builder, StartLoc);
}
void CodeGenFunction::EmitFunctionBody(FunctionArgList &Args) {
const FunctionDecl *FD = cast<FunctionDecl>(CurGD.getDecl());
assert(FD->getBody());
if (const CompoundStmt *S = dyn_cast<CompoundStmt>(FD->getBody()))
EmitCompoundStmtWithoutScope(*S);
else
EmitStmt(FD->getBody());
}
/// Tries to mark the given function nounwind based on the
/// non-existence of any throwing calls within it. We believe this is
/// lightweight enough to do at -O0.
static void TryMarkNoThrow(llvm::Function *F) {
// LLVM treats 'nounwind' on a function as part of the type, so we
// can't do this on functions that can be overwritten.
if (F->mayBeOverridden()) return;
for (llvm::Function::iterator FI = F->begin(), FE = F->end(); FI != FE; ++FI)
for (llvm::BasicBlock::iterator
BI = FI->begin(), BE = FI->end(); BI != BE; ++BI)
if (llvm::CallInst *Call = dyn_cast<llvm::CallInst>(&*BI)) {
if (!Call->doesNotThrow())
return;
} else if (isa<llvm::ResumeInst>(&*BI)) {
return;
}
F->setDoesNotThrow();
}
void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn,
const CGFunctionInfo &FnInfo) {
const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
// Check if we should generate debug info for this function.
if (!FD->hasAttr<NoDebugAttr>())
maybeInitializeDebugInfo();
FunctionArgList Args;
QualType ResTy = FD->getResultType();
CurGD = GD;
const CXXMethodDecl *MD;
if ((MD = dyn_cast<CXXMethodDecl>(FD)) && MD->isInstance()) {
if (CGM.getCXXABI().HasThisReturn(GD))
ResTy = MD->getThisType(getContext());
CGM.getCXXABI().BuildInstanceFunctionParams(*this, ResTy, Args);
}
for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i)
Args.push_back(FD->getParamDecl(i));
SourceRange BodyRange;
if (Stmt *Body = FD->getBody()) BodyRange = Body->getSourceRange();
CurEHLocation = BodyRange.getEnd();
// Emit the standard function prologue.
StartFunction(GD, ResTy, Fn, FnInfo, Args, BodyRange.getBegin());
// Generate the body of the function.
if (isa<CXXDestructorDecl>(FD))
EmitDestructorBody(Args);
else if (isa<CXXConstructorDecl>(FD))
EmitConstructorBody(Args);
else if (getLangOpts().CUDA &&
!CGM.getCodeGenOpts().CUDAIsDevice &&
FD->hasAttr<CUDAGlobalAttr>())
CGM.getCUDARuntime().EmitDeviceStubBody(*this, Args);
else if (isa<CXXConversionDecl>(FD) &&
cast<CXXConversionDecl>(FD)->isLambdaToBlockPointerConversion()) {
// The lambda conversion to block pointer is special; the semantics can't be
// expressed in the AST, so IRGen needs to special-case it.
EmitLambdaToBlockPointerBody(Args);
} else if (isa<CXXMethodDecl>(FD) &&
cast<CXXMethodDecl>(FD)->isLambdaStaticInvoker()) {
// The lambda static invoker function is special, because it forwards or
// clones the body of the function call operator (but is actually static).
EmitLambdaStaticInvokeFunction(cast<CXXMethodDecl>(FD));
} else if (FD->isDefaulted() && isa<CXXMethodDecl>(FD) &&
cast<CXXMethodDecl>(FD)->isCopyAssignmentOperator()) {
// Implicit copy-assignment gets the same special treatment as implicit
// copy-constructors.
emitImplicitAssignmentOperatorBody(Args);
}
else
EmitFunctionBody(Args);
// C++11 [stmt.return]p2:
// Flowing off the end of a function [...] results in undefined behavior in
// a value-returning function.
// C11 6.9.1p12:
// If the '}' that terminates a function is reached, and the value of the
// function call is used by the caller, the behavior is undefined.
if (getLangOpts().CPlusPlus && !FD->hasImplicitReturnZero() &&
!FD->getResultType()->isVoidType() && Builder.GetInsertBlock()) {
if (SanOpts->Return)
EmitCheck(Builder.getFalse(), "missing_return",
EmitCheckSourceLocation(FD->getLocation()),
ArrayRef<llvm::Value *>(), CRK_Unrecoverable);
else if (CGM.getCodeGenOpts().OptimizationLevel == 0)
Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::trap));
Builder.CreateUnreachable();
Builder.ClearInsertionPoint();
}
// Emit the standard function epilogue.
FinishFunction(BodyRange.getEnd());
// If we haven't marked the function nothrow through other means, do
// a quick pass now to see if we can.
if (!CurFn->doesNotThrow())
TryMarkNoThrow(CurFn);
}
/// ContainsLabel - Return true if the statement contains a label in it. If
/// this statement is not executed normally, it not containing a label means
/// that we can just remove the code.
bool CodeGenFunction::ContainsLabel(const Stmt *S, bool IgnoreCaseStmts) {
// Null statement, not a label!
if (S == 0) return false;
// If this is a label, we have to emit the code, consider something like:
// if (0) { ... foo: bar(); } goto foo;
//
// TODO: If anyone cared, we could track __label__'s, since we know that you
// can't jump to one from outside their declared region.
if (isa<LabelStmt>(S))
return true;
// If this is a case/default statement, and we haven't seen a switch, we have
// to emit the code.
if (isa<SwitchCase>(S) && !IgnoreCaseStmts)
return true;
// If this is a switch statement, we want to ignore cases below it.
if (isa<SwitchStmt>(S))
IgnoreCaseStmts = true;
// Scan subexpressions for verboten labels.
for (Stmt::const_child_range I = S->children(); I; ++I)
if (ContainsLabel(*I, IgnoreCaseStmts))
return true;
return false;
}
/// containsBreak - Return true if the statement contains a break out of it.
/// If the statement (recursively) contains a switch or loop with a break
/// inside of it, this is fine.
bool CodeGenFunction::containsBreak(const Stmt *S) {
// Null statement, not a label!
if (S == 0) return false;
// If this is a switch or loop that defines its own break scope, then we can
// include it and anything inside of it.
if (isa<SwitchStmt>(S) || isa<WhileStmt>(S) || isa<DoStmt>(S) ||
isa<ForStmt>(S))
return false;
if (isa<BreakStmt>(S))
return true;
// Scan subexpressions for verboten breaks.
for (Stmt::const_child_range I = S->children(); I; ++I)
if (containsBreak(*I))
return true;
return false;
}
/// ConstantFoldsToSimpleInteger - If the specified expression does not fold
/// to a constant, or if it does but contains a label, return false. If it
/// constant folds return true and set the boolean result in Result.
bool CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond,
bool &ResultBool) {
llvm::APSInt ResultInt;
if (!ConstantFoldsToSimpleInteger(Cond, ResultInt))
return false;
ResultBool = ResultInt.getBoolValue();
return true;
}
/// ConstantFoldsToSimpleInteger - If the specified expression does not fold
/// to a constant, or if it does but contains a label, return false. If it
/// constant folds return true and set the folded value.
bool CodeGenFunction::
ConstantFoldsToSimpleInteger(const Expr *Cond, llvm::APSInt &ResultInt) {
// FIXME: Rename and handle conversion of other evaluatable things
// to bool.
llvm::APSInt Int;
if (!Cond->EvaluateAsInt(Int, getContext()))
return false; // Not foldable, not integer or not fully evaluatable.
if (CodeGenFunction::ContainsLabel(Cond))
return false; // Contains a label.
ResultInt = Int;
return true;
}
/// EmitBranchOnBoolExpr - Emit a branch on a boolean condition (e.g. for an if
/// statement) to the specified blocks. Based on the condition, this might try
/// to simplify the codegen of the conditional based on the branch.
///
void CodeGenFunction::EmitBranchOnBoolExpr(const Expr *Cond,
llvm::BasicBlock *TrueBlock,
llvm::BasicBlock *FalseBlock) {
Cond = Cond->IgnoreParens();
if (const BinaryOperator *CondBOp = dyn_cast<BinaryOperator>(Cond)) {
// Handle X && Y in a condition.
if (CondBOp->getOpcode() == BO_LAnd) {
// If we have "1 && X", simplify the code. "0 && X" would have constant
// folded if the case was simple enough.
bool ConstantBool = false;
if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) &&
ConstantBool) {
// br(1 && X) -> br(X).
return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock);
}
// If we have "X && 1", simplify the code to use an uncond branch.
// "X && 0" would have been constant folded to 0.
if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) &&
ConstantBool) {
// br(X && 1) -> br(X).
return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock);
}
// Emit the LHS as a conditional. If the LHS conditional is false, we
// want to jump to the FalseBlock.
llvm::BasicBlock *LHSTrue = createBasicBlock("land.lhs.true");
ConditionalEvaluation eval(*this);
EmitBranchOnBoolExpr(CondBOp->getLHS(), LHSTrue, FalseBlock);
EmitBlock(LHSTrue);
// Any temporaries created here are conditional.
eval.begin(*this);
EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock);
eval.end(*this);
return;
}
if (CondBOp->getOpcode() == BO_LOr) {
// If we have "0 || X", simplify the code. "1 || X" would have constant
// folded if the case was simple enough.
bool ConstantBool = false;
if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) &&
!ConstantBool) {
// br(0 || X) -> br(X).
return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock);
}
// If we have "X || 0", simplify the code to use an uncond branch.
// "X || 1" would have been constant folded to 1.
if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) &&
!ConstantBool) {
// br(X || 0) -> br(X).
return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock);
}
// Emit the LHS as a conditional. If the LHS conditional is true, we
// want to jump to the TrueBlock.
llvm::BasicBlock *LHSFalse = createBasicBlock("lor.lhs.false");
ConditionalEvaluation eval(*this);
EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, LHSFalse);
EmitBlock(LHSFalse);
// Any temporaries created here are conditional.
eval.begin(*this);
EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock);
eval.end(*this);
return;
}
}
if (const UnaryOperator *CondUOp = dyn_cast<UnaryOperator>(Cond)) {
// br(!x, t, f) -> br(x, f, t)
if (CondUOp->getOpcode() == UO_LNot)
return EmitBranchOnBoolExpr(CondUOp->getSubExpr(), FalseBlock, TrueBlock);
}
if (const ConditionalOperator *CondOp = dyn_cast<ConditionalOperator>(Cond)) {
// br(c ? x : y, t, f) -> br(c, br(x, t, f), br(y, t, f))
llvm::BasicBlock *LHSBlock = createBasicBlock("cond.true");
llvm::BasicBlock *RHSBlock = createBasicBlock("cond.false");
ConditionalEvaluation cond(*this);
EmitBranchOnBoolExpr(CondOp->getCond(), LHSBlock, RHSBlock);
cond.begin(*this);
EmitBlock(LHSBlock);
EmitBranchOnBoolExpr(CondOp->getLHS(), TrueBlock, FalseBlock);
cond.end(*this);
cond.begin(*this);
EmitBlock(RHSBlock);
EmitBranchOnBoolExpr(CondOp->getRHS(), TrueBlock, FalseBlock);
cond.end(*this);
return;
}
if (const CXXThrowExpr *Throw = dyn_cast<CXXThrowExpr>(Cond)) {
// Conditional operator handling can give us a throw expression as a
// condition for a case like:
// br(c ? throw x : y, t, f) -> br(c, br(throw x, t, f), br(y, t, f)
// Fold this to:
// br(c, throw x, br(y, t, f))
EmitCXXThrowExpr(Throw, /*KeepInsertionPoint*/false);
return;
}
// Emit the code with the fully general case.
llvm::Value *CondV = EvaluateExprAsBool(Cond);
Builder.CreateCondBr(CondV, TrueBlock, FalseBlock);
}
/// ErrorUnsupported - Print out an error that codegen doesn't support the
/// specified stmt yet.
void CodeGenFunction::ErrorUnsupported(const Stmt *S, const char *Type) {
CGM.ErrorUnsupported(S, Type);
}
/// emitNonZeroVLAInit - Emit the "zero" initialization of a
/// variable-length array whose elements have a non-zero bit-pattern.
///
/// \param baseType the inner-most element type of the array
/// \param src - a char* pointing to the bit-pattern for a single
/// base element of the array
/// \param sizeInChars - the total size of the VLA, in chars
static void emitNonZeroVLAInit(CodeGenFunction &CGF, QualType baseType,
llvm::Value *dest, llvm::Value *src,
llvm::Value *sizeInChars) {
std::pair<CharUnits,CharUnits> baseSizeAndAlign
= CGF.getContext().getTypeInfoInChars(baseType);
CGBuilderTy &Builder = CGF.Builder;
llvm::Value *baseSizeInChars
= llvm::ConstantInt::get(CGF.IntPtrTy, baseSizeAndAlign.first.getQuantity());
llvm::Type *i8p = Builder.getInt8PtrTy();
llvm::Value *begin = Builder.CreateBitCast(dest, i8p, "vla.begin");
llvm::Value *end = Builder.CreateInBoundsGEP(dest, sizeInChars, "vla.end");
llvm::BasicBlock *originBB = CGF.Builder.GetInsertBlock();
llvm::BasicBlock *loopBB = CGF.createBasicBlock("vla-init.loop");
llvm::BasicBlock *contBB = CGF.createBasicBlock("vla-init.cont");
// Make a loop over the VLA. C99 guarantees that the VLA element
// count must be nonzero.
CGF.EmitBlock(loopBB);
llvm::PHINode *cur = Builder.CreatePHI(i8p, 2, "vla.cur");
cur->addIncoming(begin, originBB);
// memcpy the individual element bit-pattern.
Builder.CreateMemCpy(cur, src, baseSizeInChars,
baseSizeAndAlign.second.getQuantity(),
/*volatile*/ false);
// Go to the next element.
llvm::Value *next = Builder.CreateConstInBoundsGEP1_32(cur, 1, "vla.next");