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llvm-project/clang/lib/CodeGen/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 "CGOpenMPRuntime.h"
#include "CodeGenModule.h"
#include "CodeGenPGO.h"
#include "TargetInfo.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/StmtCXX.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/CodeGen/CGFunctionInfo.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(), llvm::ConstantFolder(),
CGBuilderInserterTy(this)),
CapturedStmtInfo(nullptr), SanOpts(&CGM.getLangOpts().Sanitize),
IsSanitizerScope(false), CurFuncIsThunk(false), AutoreleaseResult(false),
SawAsmBlock(false), BlockInfo(nullptr), BlockPointer(nullptr),
LambdaThisCaptureField(nullptr), NormalCleanupDest(nullptr),
NextCleanupDestIndex(1), FirstBlockInfo(nullptr), EHResumeBlock(nullptr),
ExceptionSlot(nullptr), EHSelectorSlot(nullptr),
DebugInfo(CGM.getModuleDebugInfo()), DisableDebugInfo(false),
DidCallStackSave(false), IndirectBranch(nullptr), PGO(cgm),
SwitchInsn(nullptr), SwitchWeights(nullptr), CaseRangeBlock(nullptr),
UnreachableBlock(nullptr), NumReturnExprs(0), NumSimpleReturnExprs(0),
CXXABIThisDecl(nullptr), CXXABIThisValue(nullptr), CXXThisValue(nullptr),
CXXDefaultInitExprThis(nullptr), CXXStructorImplicitParamDecl(nullptr),
CXXStructorImplicitParamValue(nullptr), OutermostConditional(nullptr),
CurLexicalScope(nullptr), TerminateLandingPad(nullptr),
TerminateHandler(nullptr), TrapBB(nullptr) {
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);
if (getLangOpts().OpenMP) {
CGM.getOpenMPRuntime().FunctionFinished(*this);
}
}
LValue CodeGenFunction::MakeNaturalAlignAddrLValue(llvm::Value *V, QualType T) {
CharUnits Alignment;
if (CGM.getCXXABI().isTypeInfoCalculable(T)) {
Alignment = getContext().getTypeAlignInChars(T);
unsigned MaxAlign = getContext().getLangOpts().MaxTypeAlign;
if (MaxAlign && Alignment.getQuantity() > MaxAlign &&
!getContext().isAlignmentRequired(T))
Alignment = CharUnits::fromQuantity(MaxAlign);
}
return LValue::MakeAddr(V, T, Alignment, getContext(), CGM.getTBAAInfo(T));
}
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()->user_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, EndLoc);
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 = nullptr;
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();
for (SmallVectorImpl<std::pair<llvm::Instruction *, llvm::Value *> >::iterator
I = DeferredReplacements.begin(),
E = DeferredReplacements.end();
I != E; ++I) {
I->first->replaceAllUsesWith(I->second);
I->first->eraseFromParent();
}
}
/// 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.
const PrintingPolicy &Policy = ASTCtx.getPrintingPolicy();
// 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 base type names.
SmallVector<llvm::Value*, 8> argBaseTypeNames;
argBaseTypeNames.push_back(
llvm::MDString::get(Context, "kernel_arg_base_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(Policy) + "*";
// Turn "unsigned type" to "utype"
std::string::size_type pos = typeName.find("unsigned");
if (pointeeTy.isCanonical() && pos != std::string::npos)
typeName.erase(pos+1, 8);
argTypeNames.push_back(llvm::MDString::get(Context, typeName));
std::string baseTypeName =
pointeeTy.getUnqualifiedType().getCanonicalType().getAsString(
Policy) +
"*";
// Turn "unsigned type" to "utype"
pos = baseTypeName.find("unsigned");
if (pos != std::string::npos)
baseTypeName.erase(pos+1, 8);
argBaseTypeNames.push_back(llvm::MDString::get(Context, baseTypeName));
// 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 {
uint32_t AddrSpc = 0;
if (ty->isImageType())
AddrSpc =
CGM.getContext().getTargetAddressSpace(LangAS::opencl_global);
addressQuals.push_back(Builder.getInt32(AddrSpc));
// Get argument type name.
std::string typeName = ty.getUnqualifiedType().getAsString(Policy);
// Turn "unsigned type" to "utype"
std::string::size_type pos = typeName.find("unsigned");
if (ty.isCanonical() && pos != std::string::npos)
typeName.erase(pos+1, 8);
argTypeNames.push_back(llvm::MDString::get(Context, typeName));
std::string baseTypeName =
ty.getUnqualifiedType().getCanonicalType().getAsString(Policy);
// Turn "unsigned type" to "utype"
pos = baseTypeName.find("unsigned");
if (pos != std::string::npos)
baseTypeName.erase(pos+1, 8);
argBaseTypeNames.push_back(llvm::MDString::get(Context, baseTypeName));
// 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()) {
const OpenCLImageAccessAttr *A = parm->getAttr<OpenCLImageAccessAttr>();
if (A && A->isWriteOnly())
accessQuals.push_back(llvm::MDString::get(Context, "write_only"));
else
accessQuals.push_back(llvm::MDString::get(Context, "read_only"));
// FIXME: what about read_write?
} 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, argBaseTypeNames));
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 (const VecTypeHintAttr *A = FD->getAttr<VecTypeHintAttr>()) {
QualType hintQTy = A->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(A->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 (const WorkGroupSizeHintAttr *A = FD->getAttr<WorkGroupSizeHintAttr>()) {
llvm::Value *attrMDArgs[] = {
llvm::MDString::get(Context, "work_group_size_hint"),
Builder.getInt32(A->getXDim()),
Builder.getInt32(A->getYDim()),
Builder.getInt32(A->getZDim())
};
kernelMDArgs.push_back(llvm::MDNode::get(Context, attrMDArgs));
}
if (const ReqdWorkGroupSizeAttr *A = FD->getAttr<ReqdWorkGroupSizeAttr>()) {
llvm::Value *attrMDArgs[] = {
llvm::MDString::get(Context, "reqd_work_group_size"),
Builder.getInt32(A->getXDim()),
Builder.getInt32(A->getYDim()),
Builder.getInt32(A->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);
}
/// Determine whether the function F ends with a return stmt.
static bool endsWithReturn(const Decl* F) {
const Stmt *Body = nullptr;
if (auto *FD = dyn_cast_or_null<FunctionDecl>(F))
Body = FD->getBody();
else if (auto *OMD = dyn_cast_or_null<ObjCMethodDecl>(F))
Body = OMD->getBody();
if (auto *CS = dyn_cast_or_null<CompoundStmt>(Body)) {
auto LastStmt = CS->body_rbegin();
if (LastStmt != CS->body_rend())
return isa<ReturnStmt>(*LastStmt);
}
return false;
}
void CodeGenFunction::StartFunction(GlobalDecl GD,
QualType RetTy,
llvm::Function *Fn,
const CGFunctionInfo &FnInfo,
const FunctionArgList &Args,
SourceLocation Loc,
SourceLocation StartLoc) {
const Decl *D = GD.getDecl();
DidCallStackSave = false;
CurCodeDecl = D;
CurFuncDecl = (D ? D->getNonClosureContext() : nullptr);
FnRetTy = RetTy;
CurFn = Fn;
CurFnInfo = &FnInfo;
assert(CurFn->isDeclaration() && "Function already has body?");
if (CGM.getSanitizerBlacklist().isIn(*Fn))
SanOpts = &SanitizerOptions::Disabled;
// Pass inline keyword to optimizer if it appears explicitly on any
// declaration. Also, in the case of -fno-inline attach NoInline
// attribute to all function that are not marked AlwaysInline.
if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) {
if (!CGM.getCodeGenOpts().NoInline) {
for (auto RI : FD->redecls())
if (RI->isInlineSpecified()) {
Fn->addFnAttr(llvm::Attribute::InlineHint);
break;
}
} else if (!FD->hasAttr<AlwaysInlineAttr>())
Fn->addFnAttr(llvm::Attribute::NoInline);
}
if (getLangOpts().OpenCL) {
// Add metadata for a kernel function.
if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D))
EmitOpenCLKernelMetadata(FD, Fn);
}
// If we are checking function types, emit a function type signature as
// prefix data.
if (getLangOpts().CPlusPlus && SanOpts->Function) {
if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) {
if (llvm::Constant *PrefixSig =
CGM.getTargetCodeGenInfo().getUBSanFunctionSignature(CGM)) {
llvm::Constant *FTRTTIConst =
CGM.GetAddrOfRTTIDescriptor(FD->getType(), /*ForEH=*/true);
llvm::Constant *PrefixStructElems[] = { PrefixSig, FTRTTIConst };
llvm::Constant *PrefixStructConst =
llvm::ConstantStruct::getAnon(PrefixStructElems, /*Packed=*/true);
Fn->setPrefixData(PrefixStructConst);
}
}
}
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->EmitFunctionStart(GD, Loc, StartLoc, FnType, CurFn, Builder);
}
if (ShouldInstrumentFunction())
EmitFunctionInstrumentation("__cyg_profile_func_enter");
if (CGM.getCodeGenOpts().InstrumentForProfiling)
EmitMCountInstrumentation();
if (RetTy->isVoidType()) {
// Void type; nothing to return.
ReturnValue = nullptr;
// Count the implicit return.
if (!endsWithReturn(D))
++NumReturnExprs;
} 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++.
auto AI = CurFn->arg_begin();
if (CurFnInfo->getReturnInfo().isSRetAfterThis())
++AI;
ReturnValue = AI;
} else if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::InAlloca &&
!hasScalarEvaluationKind(CurFnInfo->getReturnType())) {
// Load the sret pointer from the argument struct and return into that.
unsigned Idx = CurFnInfo->getReturnInfo().getInAllocaFieldIndex();
llvm::Function::arg_iterator EI = CurFn->arg_end();
--EI;
llvm::Value *Addr = Builder.CreateStructGEP(EI, Idx);
ReturnValue = Builder.CreateLoad(Addr, "agg.result");
} 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,
SourceLocation()).getScalarVal();
}
for (auto *FD : MD->getParent()->fields()) {
if (FD->hasCapturedVLAType()) {
auto *ExprArg = EmitLoadOfLValue(EmitLValueForLambdaField(FD),
SourceLocation()).getScalarVal();
auto VAT = FD->getCapturedVLAType();
VLASizeMap[VAT->getSizeExpr()] = ExprArg;
}
}
} 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 Stmt *Body) {
RegionCounter Cnt = getPGORegionCounter(Body);
Cnt.beginRegion(Builder);
if (const CompoundStmt *S = dyn_cast<CompoundStmt>(Body))
EmitCompoundStmtWithoutScope(*S);
else
EmitStmt(Body);
}
/// When instrumenting to collect profile data, the counts for some blocks
/// such as switch cases need to not include the fall-through counts, so
/// emit a branch around the instrumentation code. When not instrumenting,
/// this just calls EmitBlock().
void CodeGenFunction::EmitBlockWithFallThrough(llvm::BasicBlock *BB,
RegionCounter &Cnt) {
llvm::BasicBlock *SkipCountBB = nullptr;
if (HaveInsertPoint() && CGM.getCodeGenOpts().ProfileInstrGenerate) {
// When instrumenting for profiling, the fallthrough to certain
// statements needs to skip over the instrumentation code so that we
// get an accurate count.
SkipCountBB = createBasicBlock("skipcount");
EmitBranch(SkipCountBB);
}
EmitBlock(BB);
Cnt.beginRegion(Builder, /*AddIncomingFallThrough=*/true);
if (SkipCountBB)
EmitBlock(SkipCountBB);
}
/// 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();
}
static void EmitSizedDeallocationFunction(CodeGenFunction &CGF,
const FunctionDecl *UnsizedDealloc) {
// This is a weak discardable definition of the sized deallocation function.
CGF.CurFn->setLinkage(llvm::Function::LinkOnceAnyLinkage);
// Call the unsized deallocation function and forward the first argument
// unchanged.
llvm::Constant *Unsized = CGF.CGM.GetAddrOfFunction(UnsizedDealloc);
CGF.Builder.CreateCall(Unsized, &*CGF.CurFn->arg_begin());
}
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>())
DebugInfo = nullptr; // disable debug info indefinitely for this function
FunctionArgList Args;
QualType ResTy = FD->getReturnType();
CurGD = GD;
const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
if (MD && MD->isInstance()) {
if (CGM.getCXXABI().HasThisReturn(GD))
ResTy = MD->getThisType(getContext());
CGM.getCXXABI().buildThisParam(*this, Args);
}
Args.append(FD->param_begin(), FD->param_end());
if (MD && (isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD)))
CGM.getCXXABI().addImplicitStructorParams(*this, ResTy, Args);
SourceRange BodyRange;
if (Stmt *Body = FD->getBody()) BodyRange = Body->getSourceRange();
CurEHLocation = BodyRange.getEnd();
// Use the location of the start of the function to determine where
// the function definition is located. By default use the location
// of the declaration as the location for the subprogram. A function
// may lack a declaration in the source code if it is created by code
// gen. (examples: _GLOBAL__I_a, __cxx_global_array_dtor, thunk).
SourceLocation Loc = FD->getLocation();
// If this is a function specialization then use the pattern body
// as the location for the function.
if (const FunctionDecl *SpecDecl = FD->getTemplateInstantiationPattern())
if (SpecDecl->hasBody(SpecDecl))
Loc = SpecDecl->getLocation();
// Emit the standard function prologue.
StartFunction(GD, ResTy, Fn, FnInfo, Args, Loc, BodyRange.getBegin());
// Generate the body of the function.
PGO.checkGlobalDecl(GD);
PGO.assignRegionCounters(GD.getDecl(), CurFn);
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() ||
cast<CXXMethodDecl>(FD)->isMoveAssignmentOperator())) {
// Implicit copy-assignment gets the same special treatment as implicit
// copy-constructors.
emitImplicitAssignmentOperatorBody(Args);
} else if (Stmt *Body = FD->getBody()) {
EmitFunctionBody(Args, Body);
} else if (FunctionDecl *UnsizedDealloc =
FD->getCorrespondingUnsizedGlobalDeallocationFunction()) {
// Global sized deallocation functions get an implicit weak definition if
// they don't have an explicit definition.
EmitSizedDeallocationFunction(*this, UnsizedDealloc);
} else
llvm_unreachable("no definition for emitted function");
// 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() && !SawAsmBlock &&
!FD->getReturnType()->isVoidType() && Builder.GetInsertBlock()) {
if (SanOpts->Return) {
SanitizerScope SanScope(this);
EmitCheck(Builder.getFalse(), "missing_return",
EmitCheckSourceLocation(FD->getLocation()),
None, 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);
PGO.emitInstrumentationData();
PGO.destroyRegionCounters();
}
/// 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) 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) 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,
uint64_t TrueCount) {
Cond = Cond->IgnoreParens();
if (const BinaryOperator *CondBOp = dyn_cast<BinaryOperator>(Cond)) {
// Handle X && Y in a condition.
if (CondBOp->getOpcode() == BO_LAnd) {
RegionCounter Cnt = getPGORegionCounter(CondBOp);
// 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).
Cnt.beginRegion(Builder);
return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock,
TrueCount);
}
// 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,
TrueCount);
}
// 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");
// The counter tells us how often we evaluate RHS, and all of TrueCount
// can be propagated to that branch.
uint64_t RHSCount = Cnt.getCount();
ConditionalEvaluation eval(*this);
EmitBranchOnBoolExpr(CondBOp->getLHS(), LHSTrue, FalseBlock, RHSCount);
EmitBlock(LHSTrue);
// Any temporaries created here are conditional.
Cnt.beginRegion(Builder);
eval.begin(*this);
EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock, TrueCount);
eval.end(*this);
return;
}
if (CondBOp->getOpcode() == BO_LOr) {
RegionCounter Cnt = getPGORegionCounter(CondBOp);
// 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).
Cnt.beginRegion(Builder);
return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock,
TrueCount);
}
// 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,
TrueCount);
}
// 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");
// We have the count for entry to the RHS and for the whole expression
// being true, so we can divy up True count between the short circuit and
// the RHS.
uint64_t LHSCount = Cnt.getParentCount() - Cnt.getCount();
uint64_t RHSCount = TrueCount - LHSCount;
ConditionalEvaluation eval(*this);
EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, LHSFalse, LHSCount);
EmitBlock(LHSFalse);
// Any temporaries created here are conditional.
Cnt.beginRegion(Builder);
eval.begin(*this);
EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock, RHSCount);
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) {
// Negate the count.
uint64_t FalseCount = PGO.getCurrentRegionCount() - TrueCount;
// Negate the condition and swap the destination blocks.
return EmitBranchOnBoolExpr(CondUOp->getSubExpr(), FalseBlock, TrueBlock,
FalseCount);
}
}
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");
RegionCounter Cnt = getPGORegionCounter(CondOp);
ConditionalEvaluation cond(*this);
EmitBranchOnBoolExpr(CondOp->getCond(), LHSBlock, RHSBlock, Cnt.getCount());
// When computing PGO branch weights, we only know the overall count for
// the true block. This code is essentially doing tail duplication of the
// naive code-gen, introducing new edges for which counts are not
// available. Divide the counts proportionally between the LHS and RHS of
// the conditional operator.
uint64_t LHSScaledTrueCount = 0;
if (TrueCount) {
double LHSRatio = Cnt.getCount() / (double) Cnt.getParentCount();
LHSScaledTrueCount = TrueCount * LHSRatio;
}
cond.begin(*this);
EmitBlock(LHSBlock);
Cnt.beginRegion(Builder);
EmitBranchOnBoolExpr(CondOp->getLHS(), TrueBlock, FalseBlock,
LHSScaledTrueCount);
cond.end(*this);
cond.begin(*this);
EmitBlock(RHSBlock);
EmitBranchOnBoolExpr(CondOp->getRHS(), TrueBlock, FalseBlock,
TrueCount - LHSScaledTrueCount);
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;
}
// Create branch weights based on the number of times we get here and the
// number of times the condition should be true.
uint64_t CurrentCount = std::max(PGO.getCurrentRegionCount(), TrueCount);
llvm::MDNode *Weights = PGO.createBranchWeights(TrueCount,
CurrentCount - TrueCount);
// Emit the code with the fully general case.
llvm::Value *CondV = EvaluateExprAsBool(Cond);
Builder.CreateCondBr(CondV, TrueBlock, FalseBlock, Weights);
}
/// 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");
// Leave if that's the end of the VLA.
llvm::Value *done = Builder.CreateICmpEQ(next, end, "vla-init.isdone");
Builder.CreateCondBr(done, contBB, loopBB);
cur->addIncoming(next, loopBB);
CGF.EmitBlock(contBB);
}
void
CodeGenFunction::EmitNullInitialization(llvm::Value *DestPtr, QualType Ty) {
// Ignore empty classes in C++.
if (getLangOpts().CPlusPlus) {
if (const RecordType *RT = Ty->getAs<RecordType>()) {
if (cast<CXXRecordDecl>(RT->getDecl())->isEmpty())
return;
}
}
// Cast the dest ptr to the appropriate i8 pointer type.
unsigned DestAS =
cast<llvm::PointerType>(DestPtr->getType())->getAddressSpace();
llvm::Type *BP = Builder.getInt8PtrTy(DestAS);
if (DestPtr->getType() != BP)
DestPtr = Builder.CreateBitCast(DestPtr, BP);
// Get size and alignment info for this aggregate.
std::pair<CharUnits, CharUnits> TypeInfo =
getContext().getTypeInfoInChars(Ty);
CharUnits Size = TypeInfo.first;
CharUnits Align = TypeInfo.second;
llvm::Value *SizeVal;
const VariableArrayType *vla;
// Don't bother emitting a zero-byte memset.
if (Size.isZero()) {
// But note that getTypeInfo returns 0 for a VLA.
if (const VariableArrayType *vlaType =
dyn_cast_or_null<VariableArrayType>(
getContext().getAsArrayType(Ty))) {
QualType eltType;
llvm::Value *numElts;
std::tie(numElts, eltType) = getVLASize(vlaType);
SizeVal = numElts;
CharUnits eltSize = getContext().getTypeSizeInChars(eltType);
if (!eltSize.isOne())
SizeVal = Builder.CreateNUWMul(SizeVal, CGM.getSize(eltSize));
vla = vlaType;
} else {
return;
}
} else {
SizeVal = CGM.getSize(Size);
vla = nullptr;
}
// If the type contains a pointer to data member we can't memset it to zero.
// Instead, create a null constant and copy it to the destination.
// TODO: there are other patterns besides zero that we can usefully memset,
// like -1, which happens to be the pattern used by member-pointers.
if (!CGM.getTypes().isZeroInitializable(Ty)) {
// For a VLA, emit a single element, then splat that over the VLA.
if (vla) Ty = getContext().getBaseElementType(vla);
llvm::Constant *NullConstant = CGM.EmitNullConstant(Ty);
llvm::GlobalVariable *NullVariable =
new llvm::GlobalVariable(CGM.getModule(), NullConstant->getType(),
/*isConstant=*/true,
llvm::GlobalVariable::PrivateLinkage,
NullConstant, Twine());
llvm::Value *SrcPtr =
Builder.CreateBitCast(NullVariable, Builder.getInt8PtrTy());
if (vla) return emitNonZeroVLAInit(*this, Ty, DestPtr, SrcPtr, SizeVal);
// Get and call the appropriate llvm.memcpy overload.
Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, Align.getQuantity(), false);
return;
}
// Otherwise, just memset the whole thing to zero. This is legal
// because in LLVM, all default initializers (other than the ones we just
// handled above) are guaranteed to have a bit pattern of all zeros.
Builder.CreateMemSet(DestPtr, Builder.getInt8(0), SizeVal,
Align.getQuantity(), false);
}
llvm::BlockAddress *CodeGenFunction::GetAddrOfLabel(const LabelDecl *L) {
// Make sure that there is a block for the indirect goto.
if (!IndirectBranch)
GetIndirectGotoBlock();
llvm::BasicBlock *BB = getJumpDestForLabel(L).getBlock();
// Make sure the indirect branch includes all of the address-taken blocks.
IndirectBranch->addDestination(BB);
return llvm::BlockAddress::get(CurFn, BB);
}
llvm::BasicBlock *CodeGenFunction::GetIndirectGotoBlock() {
// If we already made the indirect branch for indirect goto, return its block.
if (IndirectBranch) return IndirectBranch->getParent();
CGBuilderTy TmpBuilder(createBasicBlock("indirectgoto"));
// Create the PHI node that indirect gotos will add entries to.
llvm::Value *DestVal = TmpBuilder.CreatePHI(Int8PtrTy, 0,
"indirect.goto.dest");
// Create the indirect branch instruction.
IndirectBranch = TmpBuilder.CreateIndirectBr(DestVal);
return IndirectBranch->getParent();
}
/// Computes the length of an array in elements, as well as the base
/// element type and a properly-typed first element pointer.
llvm::Value *CodeGenFunction::emitArrayLength(const ArrayType *origArrayType,
QualType &baseType,
llvm::Value *&addr) {
const ArrayType *arrayType = origArrayType;
// If it's a VLA, we have to load the stored size. Note that
// this is the size of the VLA in bytes, not its size in elements.
llvm::Value *numVLAElements = nullptr;
if (isa<VariableArrayType>(arrayType)) {
numVLAElements = getVLASize(cast<VariableArrayType>(arrayType)).first;
// Walk into all VLAs. This doesn't require changes to addr,
// which has type T* where T is the first non-VLA element type.
do {
QualType elementType = arrayType->getElementType();
arrayType = getContext().getAsArrayType(elementType);
// If we only have VLA components, 'addr' requires no adjustment.
if (!arrayType) {
baseType = elementType;
return numVLAElements;
}
} while (isa<VariableArrayType>(arrayType));
// We get out here only if we find a constant array type
// inside the VLA.
}
// We have some number of constant-length arrays, so addr should
// have LLVM type [M x [N x [...]]]*. Build a GEP that walks
// down to the first element of addr.
SmallVector<llvm::Value*, 8> gepIndices;
// GEP down to the array type.
llvm::ConstantInt *zero = Builder.getInt32(0);
gepIndices.push_back(zero);
uint64_t countFromCLAs = 1;
QualType eltType;
llvm::ArrayType *llvmArrayType =
dyn_cast<llvm::ArrayType>(
cast<llvm::PointerType>(addr->getType())->getElementType());
while (llvmArrayType) {
assert(isa<ConstantArrayType>(arrayType));
assert(cast<ConstantArrayType>(arrayType)->getSize().getZExtValue()
== llvmArrayType->getNumElements());
gepIndices.push_back(zero);
countFromCLAs *= llvmArrayType->getNumElements();
eltType = arrayType->getElementType();
llvmArrayType =
dyn_cast<llvm::ArrayType>(llvmArrayType->getElementType());
arrayType = getContext().getAsArrayType(arrayType->getElementType());
assert((!llvmArrayType || arrayType) &&
"LLVM and Clang types are out-of-synch");
}
if (arrayType) {
// From this point onwards, the Clang array type has been emitted
// as some other type (probably a packed struct). Compute the array
// size, and just emit the 'begin' expression as a bitcast.
while (arrayType) {
countFromCLAs *=
cast<ConstantArrayType>(arrayType)->getSize().getZExtValue();
eltType = arrayType->getElementType();
arrayType = getContext().getAsArrayType(eltType);
}
unsigned AddressSpace = addr->getType()->getPointerAddressSpace();
llvm::Type *BaseType = ConvertType(eltType)->getPointerTo(AddressSpace);
addr = Builder.CreateBitCast(addr, BaseType, "array.begin");
} else {
// Create the actual GEP.
addr = Builder.CreateInBoundsGEP(addr, gepIndices, "array.begin");
}
baseType = eltType;
llvm::Value *numElements
= llvm::ConstantInt::get(SizeTy, countFromCLAs);
// If we had any VLA dimensions, factor them in.
if (numVLAElements)
numElements = Builder.CreateNUWMul(numVLAElements, numElements);
return numElements;
}
std::pair<llvm::Value*, QualType>
CodeGenFunction::getVLASize(QualType type) {
const VariableArrayType *vla = getContext().getAsVariableArrayType(type);
assert(vla && "type was not a variable array type!");
return getVLASize(vla);
}
std::pair<llvm::Value*, QualType>
CodeGenFunction::getVLASize(const VariableArrayType *type) {
// The number of elements so far; always size_t.
llvm::Value *numElements = nullptr;
QualType elementType;
do {
elementType = type->getElementType();
llvm::Value *vlaSize = VLASizeMap[type->getSizeExpr()];
assert(vlaSize && "no size for VLA!");
assert(vlaSize->getType() == SizeTy);
if (!numElements) {
numElements = vlaSize;
} else {
// It's undefined behavior if this wraps around, so mark it that way.
// FIXME: Teach -fsanitize=undefined to trap this.
numElements = Builder.CreateNUWMul(numElements, vlaSize);
}
} while ((type = getContext().getAsVariableArrayType(elementType)));
return std::pair<llvm::Value*,QualType>(numElements, elementType);
}
void CodeGenFunction::EmitVariablyModifiedType(QualType type) {
assert(type->isVariablyModifiedType() &&
"Must pass variably modified type to EmitVLASizes!");
EnsureInsertPoint();
// We're going to walk down into the type and look for VLA
// expressions.
do {
assert(type->isVariablyModifiedType());
const Type *ty = type.getTypePtr();
switch (ty->getTypeClass()) {
#define TYPE(Class, Base)
#define ABSTRACT_TYPE(Class, Base)
#define NON_CANONICAL_TYPE(Class, Base)
#define DEPENDENT_TYPE(Class, Base) case Type::Class:
#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base)
#include "clang/AST/TypeNodes.def"
llvm_unreachable("unexpected dependent type!");
// These types are never variably-modified.
case Type::Builtin:
case Type::Complex:
case Type::Vector:
case Type::ExtVector:
case Type::Record:
case Type::Enum:
case Type::Elaborated:
case Type::TemplateSpecialization:
case Type::ObjCObject:
case Type::ObjCInterface:
case Type::ObjCObjectPointer:
llvm_unreachable("type class is never variably-modified!");
case Type::Adjusted:
type = cast<AdjustedType>(ty)->getAdjustedType();
break;
case Type::Decayed:
type = cast<DecayedType>(ty)->getPointeeType();
break;
case Type::Pointer:
type = cast<PointerType>(ty)->getPointeeType();
break;
case Type::BlockPointer:
type = cast<BlockPointerType>(ty)->getPointeeType();
break;
case Type::LValueReference:
case Type::RValueReference:
type = cast<ReferenceType>(ty)->getPointeeType();
break;
case Type::MemberPointer:
type = cast<MemberPointerType>(ty)->getPointeeType();
break;
case Type::ConstantArray:
case Type::IncompleteArray:
// Losing element qualification here is fine.
type = cast<ArrayType>(ty)->getElementType();
break;
case Type::VariableArray: {
// Losing element qualification here is fine.
const VariableArrayType *vat = cast<VariableArrayType>(ty);
// Unknown size indication requires no size computation.
// Otherwise, evaluate and record it.
if (const Expr *size = vat->getSizeExpr()) {
// It's possible that we might have emitted this already,
// e.g. with a typedef and a pointer to it.
llvm::Value *&entry = VLASizeMap[size];
if (!entry) {
llvm::Value *Size = EmitScalarExpr(size);
// C11 6.7.6.2p5:
// If the size is an expression that is not an integer constant
// expression [...] each time it is evaluated it shall have a value
// greater than zero.
if (SanOpts->VLABound &&
size->getType()->isSignedIntegerType()) {
SanitizerScope SanScope(this);
llvm::Value *Zero = llvm::Constant::getNullValue(Size->getType());
llvm::Constant *StaticArgs[] = {
EmitCheckSourceLocation(size->getLocStart()),
EmitCheckTypeDescriptor(size->getType())
};
EmitCheck(Builder.CreateICmpSGT(Size, Zero),
"vla_bound_not_positive", StaticArgs, Size,
CRK_Recoverable);
}
// Always zexting here would be wrong if it weren't
// undefined behavior to have a negative bound.
entry = Builder.CreateIntCast(Size, SizeTy, /*signed*/ false);
}
}
type = vat->getElementType();
break;
}
case Type::FunctionProto:
case Type::FunctionNoProto:
type = cast<FunctionType>(ty)->getReturnType();
break;
case Type::Paren:
case Type::TypeOf:
case Type::UnaryTransform:
case Type::Attributed:
case Type::SubstTemplateTypeParm:
case Type::PackExpansion:
// Keep walking after single level desugaring.
type = type.getSingleStepDesugaredType(getContext());
break;
case Type::Typedef:
case Type::Decltype:
case Type::Auto:
// Stop walking: nothing to do.
return;
case Type::TypeOfExpr:
// Stop walking: emit typeof expression.
EmitIgnoredExpr(cast<TypeOfExprType>(ty)->getUnderlyingExpr());
return;
case Type::Atomic:
type = cast<AtomicType>(ty)->getValueType();
break;
}
} while (type->isVariablyModifiedType());
}
llvm::Value* CodeGenFunction::EmitVAListRef(const Expr* E) {
if (getContext().getBuiltinVaListType()->isArrayType())
return EmitScalarExpr(E);
return EmitLValue(E).getAddress();
}
void CodeGenFunction::EmitDeclRefExprDbgValue(const DeclRefExpr *E,
llvm::Constant *Init) {
assert (Init && "Invalid DeclRefExpr initializer!");
if (CGDebugInfo *Dbg = getDebugInfo())
if (CGM.getCodeGenOpts().getDebugInfo() >= CodeGenOptions::LimitedDebugInfo)
Dbg->EmitGlobalVariable(E->getDecl(), Init);
}
CodeGenFunction::PeepholeProtection
CodeGenFunction::protectFromPeepholes(RValue rvalue) {
// At the moment, the only aggressive peephole we do in IR gen
// is trunc(zext) folding, but if we add more, we can easily
// extend this protection.
if (!rvalue.isScalar()) return PeepholeProtection();
llvm::Value *value = rvalue.getScalarVal();
if (!isa<llvm::ZExtInst>(value)) return PeepholeProtection();
// Just make an extra bitcast.
assert(HaveInsertPoint());
llvm::Instruction *inst = new llvm::BitCastInst(value, value->getType(), "",
Builder.GetInsertBlock());
PeepholeProtection protection;
protection.Inst = inst;
return protection;
}
void CodeGenFunction::unprotectFromPeepholes(PeepholeProtection protection) {
if (!protection.Inst) return;
// In theory, we could try to duplicate the peepholes now, but whatever.
protection.Inst->eraseFromParent();
}
llvm::Value *CodeGenFunction::EmitAnnotationCall(llvm::Value *AnnotationFn,
llvm::Value *AnnotatedVal,
StringRef AnnotationStr,
SourceLocation Location) {
llvm::Value *Args[4] = {
AnnotatedVal,
Builder.CreateBitCast(CGM.EmitAnnotationString(AnnotationStr), Int8PtrTy),
Builder.CreateBitCast(CGM.EmitAnnotationUnit(Location), Int8PtrTy),
CGM.EmitAnnotationLineNo(Location)
};
return Builder.CreateCall(AnnotationFn, Args);
}
void CodeGenFunction::EmitVarAnnotations(const VarDecl *D, llvm::Value *V) {
assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute");
// FIXME We create a new bitcast for every annotation because that's what
// llvm-gcc was doing.
for (const auto *I : D->specific_attrs<AnnotateAttr>())
EmitAnnotationCall(CGM.getIntrinsic(llvm::Intrinsic::var_annotation),
Builder.CreateBitCast(V, CGM.Int8PtrTy, V->getName()),
I->getAnnotation(), D->getLocation());
}
llvm::Value *CodeGenFunction::EmitFieldAnnotations(const FieldDecl *D,
llvm::Value *V) {
assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute");
llvm::Type *VTy = V->getType();
llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::ptr_annotation,
CGM.Int8PtrTy);
for (const auto *I : D->specific_attrs<AnnotateAttr>()) {
// FIXME Always emit the cast inst so we can differentiate between
// annotation on the first field of a struct and annotation on the struct
// itself.
if (VTy != CGM.Int8PtrTy)
V = Builder.Insert(new llvm::BitCastInst(V, CGM.Int8PtrTy));
V = EmitAnnotationCall(F, V, I->getAnnotation(), D->getLocation());
V = Builder.CreateBitCast(V, VTy);
}
return V;
}
CodeGenFunction::CGCapturedStmtInfo::~CGCapturedStmtInfo() { }
CodeGenFunction::SanitizerScope::SanitizerScope(CodeGenFunction *CGF)
: CGF(CGF) {
assert(!CGF->IsSanitizerScope);
CGF->IsSanitizerScope = true;
}
CodeGenFunction::SanitizerScope::~SanitizerScope() {
CGF->IsSanitizerScope = false;
}
void CodeGenFunction::InsertHelper(llvm::Instruction *I,
const llvm::Twine &Name,
llvm::BasicBlock *BB,
llvm::BasicBlock::iterator InsertPt) const {
LoopStack.InsertHelper(I);
if (IsSanitizerScope)
CGM.getSanitizerMetadata()->disableSanitizerForInstruction(I);
}
template <bool PreserveNames>
void CGBuilderInserter<PreserveNames>::InsertHelper(
llvm::Instruction *I, const llvm::Twine &Name, llvm::BasicBlock *BB,
llvm::BasicBlock::iterator InsertPt) const {
llvm::IRBuilderDefaultInserter<PreserveNames>::InsertHelper(I, Name, BB,
InsertPt);
if (CGF)
CGF->InsertHelper(I, Name, BB, InsertPt);
}
#ifdef NDEBUG
#define PreserveNames false
#else
#define PreserveNames true
#endif
template void CGBuilderInserter<PreserveNames>::InsertHelper(
llvm::Instruction *I, const llvm::Twine &Name, llvm::BasicBlock *BB,
llvm::BasicBlock::iterator InsertPt) const;
#undef PreserveNames
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