forked from OSchip/llvm-project
452 lines
17 KiB
C++
452 lines
17 KiB
C++
//===--- CGDeclCXX.cpp - Emit LLVM Code for C++ declarations --------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This contains code dealing with code generation of C++ declarations
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "CodeGenFunction.h"
|
|
#include "CGCXXABI.h"
|
|
#include "CGObjCRuntime.h"
|
|
#include "clang/Frontend/CodeGenOptions.h"
|
|
#include "llvm/ADT/StringExtras.h"
|
|
#include "llvm/IR/Intrinsics.h"
|
|
|
|
using namespace clang;
|
|
using namespace CodeGen;
|
|
|
|
static void EmitDeclInit(CodeGenFunction &CGF, const VarDecl &D,
|
|
llvm::Constant *DeclPtr) {
|
|
assert(D.hasGlobalStorage() && "VarDecl must have global storage!");
|
|
assert(!D.getType()->isReferenceType() &&
|
|
"Should not call EmitDeclInit on a reference!");
|
|
|
|
ASTContext &Context = CGF.getContext();
|
|
|
|
CharUnits alignment = Context.getDeclAlign(&D);
|
|
QualType type = D.getType();
|
|
LValue lv = CGF.MakeAddrLValue(DeclPtr, type, alignment);
|
|
|
|
const Expr *Init = D.getInit();
|
|
if (!CGF.hasAggregateLLVMType(type)) {
|
|
CodeGenModule &CGM = CGF.CGM;
|
|
if (lv.isObjCStrong())
|
|
CGM.getObjCRuntime().EmitObjCGlobalAssign(CGF, CGF.EmitScalarExpr(Init),
|
|
DeclPtr, D.isThreadSpecified());
|
|
else if (lv.isObjCWeak())
|
|
CGM.getObjCRuntime().EmitObjCWeakAssign(CGF, CGF.EmitScalarExpr(Init),
|
|
DeclPtr);
|
|
else
|
|
CGF.EmitScalarInit(Init, &D, lv, false);
|
|
} else if (type->isAnyComplexType()) {
|
|
CGF.EmitComplexExprIntoAddr(Init, DeclPtr, lv.isVolatile());
|
|
} else {
|
|
CGF.EmitAggExpr(Init, AggValueSlot::forLValue(lv,AggValueSlot::IsDestructed,
|
|
AggValueSlot::DoesNotNeedGCBarriers,
|
|
AggValueSlot::IsNotAliased));
|
|
}
|
|
}
|
|
|
|
/// Emit code to cause the destruction of the given variable with
|
|
/// static storage duration.
|
|
static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D,
|
|
llvm::Constant *addr) {
|
|
CodeGenModule &CGM = CGF.CGM;
|
|
|
|
// FIXME: __attribute__((cleanup)) ?
|
|
|
|
QualType type = D.getType();
|
|
QualType::DestructionKind dtorKind = type.isDestructedType();
|
|
|
|
switch (dtorKind) {
|
|
case QualType::DK_none:
|
|
return;
|
|
|
|
case QualType::DK_cxx_destructor:
|
|
break;
|
|
|
|
case QualType::DK_objc_strong_lifetime:
|
|
case QualType::DK_objc_weak_lifetime:
|
|
// We don't care about releasing objects during process teardown.
|
|
return;
|
|
}
|
|
|
|
llvm::Constant *function;
|
|
llvm::Constant *argument;
|
|
|
|
// Special-case non-array C++ destructors, where there's a function
|
|
// with the right signature that we can just call.
|
|
const CXXRecordDecl *record = 0;
|
|
if (dtorKind == QualType::DK_cxx_destructor &&
|
|
(record = type->getAsCXXRecordDecl())) {
|
|
assert(!record->hasTrivialDestructor());
|
|
CXXDestructorDecl *dtor = record->getDestructor();
|
|
|
|
function = CGM.GetAddrOfCXXDestructor(dtor, Dtor_Complete);
|
|
argument = addr;
|
|
|
|
// Otherwise, the standard logic requires a helper function.
|
|
} else {
|
|
function = CodeGenFunction(CGM).generateDestroyHelper(addr, type,
|
|
CGF.getDestroyer(dtorKind),
|
|
CGF.needsEHCleanup(dtorKind));
|
|
argument = llvm::Constant::getNullValue(CGF.Int8PtrTy);
|
|
}
|
|
|
|
CGM.getCXXABI().registerGlobalDtor(CGF, function, argument);
|
|
}
|
|
|
|
/// Emit code to cause the variable at the given address to be considered as
|
|
/// constant from this point onwards.
|
|
static void EmitDeclInvariant(CodeGenFunction &CGF, const VarDecl &D,
|
|
llvm::Constant *Addr) {
|
|
// Don't emit the intrinsic if we're not optimizing.
|
|
if (!CGF.CGM.getCodeGenOpts().OptimizationLevel)
|
|
return;
|
|
|
|
// Grab the llvm.invariant.start intrinsic.
|
|
llvm::Intrinsic::ID InvStartID = llvm::Intrinsic::invariant_start;
|
|
llvm::Constant *InvariantStart = CGF.CGM.getIntrinsic(InvStartID);
|
|
|
|
// Emit a call with the size in bytes of the object.
|
|
CharUnits WidthChars = CGF.getContext().getTypeSizeInChars(D.getType());
|
|
uint64_t Width = WidthChars.getQuantity();
|
|
llvm::Value *Args[2] = { llvm::ConstantInt::getSigned(CGF.Int64Ty, Width),
|
|
llvm::ConstantExpr::getBitCast(Addr, CGF.Int8PtrTy)};
|
|
CGF.Builder.CreateCall(InvariantStart, Args);
|
|
}
|
|
|
|
void CodeGenFunction::EmitCXXGlobalVarDeclInit(const VarDecl &D,
|
|
llvm::Constant *DeclPtr,
|
|
bool PerformInit) {
|
|
|
|
const Expr *Init = D.getInit();
|
|
QualType T = D.getType();
|
|
|
|
if (!T->isReferenceType()) {
|
|
if (PerformInit)
|
|
EmitDeclInit(*this, D, DeclPtr);
|
|
if (CGM.isTypeConstant(D.getType(), true))
|
|
EmitDeclInvariant(*this, D, DeclPtr);
|
|
else
|
|
EmitDeclDestroy(*this, D, DeclPtr);
|
|
return;
|
|
}
|
|
|
|
assert(PerformInit && "cannot have constant initializer which needs "
|
|
"destruction for reference");
|
|
unsigned Alignment = getContext().getDeclAlign(&D).getQuantity();
|
|
RValue RV = EmitReferenceBindingToExpr(Init, &D);
|
|
EmitStoreOfScalar(RV.getScalarVal(), DeclPtr, false, Alignment, T);
|
|
}
|
|
|
|
static llvm::Function *
|
|
CreateGlobalInitOrDestructFunction(CodeGenModule &CGM,
|
|
llvm::FunctionType *ty,
|
|
const Twine &name);
|
|
|
|
/// Create a stub function, suitable for being passed to atexit,
|
|
/// which passes the given address to the given destructor function.
|
|
static llvm::Constant *createAtExitStub(CodeGenModule &CGM,
|
|
llvm::Constant *dtor,
|
|
llvm::Constant *addr) {
|
|
// Get the destructor function type, void(*)(void).
|
|
llvm::FunctionType *ty = llvm::FunctionType::get(CGM.VoidTy, false);
|
|
llvm::Function *fn =
|
|
CreateGlobalInitOrDestructFunction(CGM, ty,
|
|
Twine("__dtor_", addr->getName()));
|
|
|
|
CodeGenFunction CGF(CGM);
|
|
|
|
// Initialize debug info if needed.
|
|
CGF.maybeInitializeDebugInfo();
|
|
|
|
CGF.StartFunction(GlobalDecl(), CGM.getContext().VoidTy, fn,
|
|
CGM.getTypes().arrangeNullaryFunction(),
|
|
FunctionArgList(), SourceLocation());
|
|
|
|
llvm::CallInst *call = CGF.Builder.CreateCall(dtor, addr);
|
|
|
|
// Make sure the call and the callee agree on calling convention.
|
|
if (llvm::Function *dtorFn =
|
|
dyn_cast<llvm::Function>(dtor->stripPointerCasts()))
|
|
call->setCallingConv(dtorFn->getCallingConv());
|
|
|
|
CGF.FinishFunction();
|
|
|
|
return fn;
|
|
}
|
|
|
|
/// Register a global destructor using the C atexit runtime function.
|
|
void CodeGenFunction::registerGlobalDtorWithAtExit(llvm::Constant *dtor,
|
|
llvm::Constant *addr) {
|
|
// Create a function which calls the destructor.
|
|
llvm::Constant *dtorStub = createAtExitStub(CGM, dtor, addr);
|
|
|
|
// extern "C" int atexit(void (*f)(void));
|
|
llvm::FunctionType *atexitTy =
|
|
llvm::FunctionType::get(IntTy, dtorStub->getType(), false);
|
|
|
|
llvm::Constant *atexit =
|
|
CGM.CreateRuntimeFunction(atexitTy, "atexit");
|
|
if (llvm::Function *atexitFn = dyn_cast<llvm::Function>(atexit))
|
|
atexitFn->setDoesNotThrow();
|
|
|
|
Builder.CreateCall(atexit, dtorStub)->setDoesNotThrow();
|
|
}
|
|
|
|
void CodeGenFunction::EmitCXXGuardedInit(const VarDecl &D,
|
|
llvm::GlobalVariable *DeclPtr,
|
|
bool PerformInit) {
|
|
// If we've been asked to forbid guard variables, emit an error now.
|
|
// This diagnostic is hard-coded for Darwin's use case; we can find
|
|
// better phrasing if someone else needs it.
|
|
if (CGM.getCodeGenOpts().ForbidGuardVariables)
|
|
CGM.Error(D.getLocation(),
|
|
"this initialization requires a guard variable, which "
|
|
"the kernel does not support");
|
|
|
|
CGM.getCXXABI().EmitGuardedInit(*this, D, DeclPtr, PerformInit);
|
|
}
|
|
|
|
static llvm::Function *
|
|
CreateGlobalInitOrDestructFunction(CodeGenModule &CGM,
|
|
llvm::FunctionType *FTy,
|
|
const Twine &Name) {
|
|
llvm::Function *Fn =
|
|
llvm::Function::Create(FTy, llvm::GlobalValue::InternalLinkage,
|
|
Name, &CGM.getModule());
|
|
if (!CGM.getLangOpts().AppleKext) {
|
|
// Set the section if needed.
|
|
if (const char *Section =
|
|
CGM.getContext().getTargetInfo().getStaticInitSectionSpecifier())
|
|
Fn->setSection(Section);
|
|
}
|
|
|
|
if (!CGM.getLangOpts().Exceptions)
|
|
Fn->setDoesNotThrow();
|
|
|
|
if (CGM.getLangOpts().SanitizeAddress)
|
|
Fn->addFnAttr(llvm::Attribute::AddressSafety);
|
|
|
|
return Fn;
|
|
}
|
|
|
|
void
|
|
CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
|
|
llvm::GlobalVariable *Addr,
|
|
bool PerformInit) {
|
|
llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
|
|
|
|
// Create a variable initialization function.
|
|
llvm::Function *Fn =
|
|
CreateGlobalInitOrDestructFunction(*this, FTy, "__cxx_global_var_init");
|
|
|
|
CodeGenFunction(*this).GenerateCXXGlobalVarDeclInitFunc(Fn, D, Addr,
|
|
PerformInit);
|
|
|
|
if (D->hasAttr<InitPriorityAttr>()) {
|
|
unsigned int order = D->getAttr<InitPriorityAttr>()->getPriority();
|
|
OrderGlobalInits Key(order, PrioritizedCXXGlobalInits.size());
|
|
PrioritizedCXXGlobalInits.push_back(std::make_pair(Key, Fn));
|
|
DelayedCXXInitPosition.erase(D);
|
|
} else {
|
|
llvm::DenseMap<const Decl *, unsigned>::iterator I =
|
|
DelayedCXXInitPosition.find(D);
|
|
if (I == DelayedCXXInitPosition.end()) {
|
|
CXXGlobalInits.push_back(Fn);
|
|
} else {
|
|
assert(CXXGlobalInits[I->second] == 0);
|
|
CXXGlobalInits[I->second] = Fn;
|
|
DelayedCXXInitPosition.erase(I);
|
|
}
|
|
}
|
|
}
|
|
|
|
void
|
|
CodeGenModule::EmitCXXGlobalInitFunc() {
|
|
while (!CXXGlobalInits.empty() && !CXXGlobalInits.back())
|
|
CXXGlobalInits.pop_back();
|
|
|
|
if (CXXGlobalInits.empty() && PrioritizedCXXGlobalInits.empty())
|
|
return;
|
|
|
|
llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
|
|
|
|
|
|
// Create our global initialization function.
|
|
if (!PrioritizedCXXGlobalInits.empty()) {
|
|
SmallVector<llvm::Constant*, 8> LocalCXXGlobalInits;
|
|
llvm::array_pod_sort(PrioritizedCXXGlobalInits.begin(),
|
|
PrioritizedCXXGlobalInits.end());
|
|
// Iterate over "chunks" of ctors with same priority and emit each chunk
|
|
// into separate function. Note - everything is sorted first by priority,
|
|
// second - by lex order, so we emit ctor functions in proper order.
|
|
for (SmallVectorImpl<GlobalInitData >::iterator
|
|
I = PrioritizedCXXGlobalInits.begin(),
|
|
E = PrioritizedCXXGlobalInits.end(); I != E; ) {
|
|
SmallVectorImpl<GlobalInitData >::iterator
|
|
PrioE = std::upper_bound(I + 1, E, *I, GlobalInitPriorityCmp());
|
|
|
|
LocalCXXGlobalInits.clear();
|
|
unsigned Priority = I->first.priority;
|
|
// Compute the function suffix from priority. Prepend with zeroes to make
|
|
// sure the function names are also ordered as priorities.
|
|
std::string PrioritySuffix = llvm::utostr(Priority);
|
|
// Priority is always <= 65535 (enforced by sema)..
|
|
PrioritySuffix = std::string(6-PrioritySuffix.size(), '0')+PrioritySuffix;
|
|
llvm::Function *Fn =
|
|
CreateGlobalInitOrDestructFunction(*this, FTy,
|
|
"_GLOBAL__I_" + PrioritySuffix);
|
|
|
|
for (; I < PrioE; ++I)
|
|
LocalCXXGlobalInits.push_back(I->second);
|
|
|
|
CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn,
|
|
&LocalCXXGlobalInits[0],
|
|
LocalCXXGlobalInits.size());
|
|
AddGlobalCtor(Fn, Priority);
|
|
}
|
|
}
|
|
|
|
llvm::Function *Fn =
|
|
CreateGlobalInitOrDestructFunction(*this, FTy, "_GLOBAL__I_a");
|
|
|
|
CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn,
|
|
&CXXGlobalInits[0],
|
|
CXXGlobalInits.size());
|
|
AddGlobalCtor(Fn);
|
|
|
|
CXXGlobalInits.clear();
|
|
PrioritizedCXXGlobalInits.clear();
|
|
}
|
|
|
|
void CodeGenModule::EmitCXXGlobalDtorFunc() {
|
|
if (CXXGlobalDtors.empty())
|
|
return;
|
|
|
|
llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
|
|
|
|
// Create our global destructor function.
|
|
llvm::Function *Fn =
|
|
CreateGlobalInitOrDestructFunction(*this, FTy, "_GLOBAL__D_a");
|
|
|
|
CodeGenFunction(*this).GenerateCXXGlobalDtorsFunc(Fn, CXXGlobalDtors);
|
|
AddGlobalDtor(Fn);
|
|
}
|
|
|
|
/// Emit the code necessary to initialize the given global variable.
|
|
void CodeGenFunction::GenerateCXXGlobalVarDeclInitFunc(llvm::Function *Fn,
|
|
const VarDecl *D,
|
|
llvm::GlobalVariable *Addr,
|
|
bool PerformInit) {
|
|
// Check if we need to emit debug info for variable initializer.
|
|
if (!D->hasAttr<NoDebugAttr>())
|
|
maybeInitializeDebugInfo();
|
|
|
|
StartFunction(GlobalDecl(D), getContext().VoidTy, Fn,
|
|
getTypes().arrangeNullaryFunction(),
|
|
FunctionArgList(), D->getInit()->getExprLoc());
|
|
|
|
// Use guarded initialization if the global variable is weak. This
|
|
// occurs for, e.g., instantiated static data members and
|
|
// definitions explicitly marked weak.
|
|
if (Addr->getLinkage() == llvm::GlobalValue::WeakODRLinkage ||
|
|
Addr->getLinkage() == llvm::GlobalValue::WeakAnyLinkage) {
|
|
EmitCXXGuardedInit(*D, Addr, PerformInit);
|
|
} else {
|
|
EmitCXXGlobalVarDeclInit(*D, Addr, PerformInit);
|
|
}
|
|
|
|
FinishFunction();
|
|
}
|
|
|
|
void CodeGenFunction::GenerateCXXGlobalInitFunc(llvm::Function *Fn,
|
|
llvm::Constant **Decls,
|
|
unsigned NumDecls) {
|
|
// Initialize debug info if needed.
|
|
maybeInitializeDebugInfo();
|
|
|
|
StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
|
|
getTypes().arrangeNullaryFunction(),
|
|
FunctionArgList(), SourceLocation());
|
|
|
|
RunCleanupsScope Scope(*this);
|
|
|
|
// When building in Objective-C++ ARC mode, create an autorelease pool
|
|
// around the global initializers.
|
|
if (getLangOpts().ObjCAutoRefCount && getLangOpts().CPlusPlus) {
|
|
llvm::Value *token = EmitObjCAutoreleasePoolPush();
|
|
EmitObjCAutoreleasePoolCleanup(token);
|
|
}
|
|
|
|
for (unsigned i = 0; i != NumDecls; ++i)
|
|
if (Decls[i])
|
|
Builder.CreateCall(Decls[i]);
|
|
|
|
Scope.ForceCleanup();
|
|
|
|
FinishFunction();
|
|
}
|
|
|
|
void CodeGenFunction::GenerateCXXGlobalDtorsFunc(llvm::Function *Fn,
|
|
const std::vector<std::pair<llvm::WeakVH, llvm::Constant*> >
|
|
&DtorsAndObjects) {
|
|
// Initialize debug info if needed.
|
|
maybeInitializeDebugInfo();
|
|
|
|
StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
|
|
getTypes().arrangeNullaryFunction(),
|
|
FunctionArgList(), SourceLocation());
|
|
|
|
// Emit the dtors, in reverse order from construction.
|
|
for (unsigned i = 0, e = DtorsAndObjects.size(); i != e; ++i) {
|
|
llvm::Value *Callee = DtorsAndObjects[e - i - 1].first;
|
|
llvm::CallInst *CI = Builder.CreateCall(Callee,
|
|
DtorsAndObjects[e - i - 1].second);
|
|
// Make sure the call and the callee agree on calling convention.
|
|
if (llvm::Function *F = dyn_cast<llvm::Function>(Callee))
|
|
CI->setCallingConv(F->getCallingConv());
|
|
}
|
|
|
|
FinishFunction();
|
|
}
|
|
|
|
/// generateDestroyHelper - Generates a helper function which, when
|
|
/// invoked, destroys the given object.
|
|
llvm::Function *
|
|
CodeGenFunction::generateDestroyHelper(llvm::Constant *addr,
|
|
QualType type,
|
|
Destroyer *destroyer,
|
|
bool useEHCleanupForArray) {
|
|
FunctionArgList args;
|
|
ImplicitParamDecl dst(0, SourceLocation(), 0, getContext().VoidPtrTy);
|
|
args.push_back(&dst);
|
|
|
|
const CGFunctionInfo &FI =
|
|
CGM.getTypes().arrangeFunctionDeclaration(getContext().VoidTy, args,
|
|
FunctionType::ExtInfo(),
|
|
/*variadic*/ false);
|
|
llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(FI);
|
|
llvm::Function *fn =
|
|
CreateGlobalInitOrDestructFunction(CGM, FTy, "__cxx_global_array_dtor");
|
|
|
|
// Initialize debug info if needed.
|
|
maybeInitializeDebugInfo();
|
|
|
|
StartFunction(GlobalDecl(), getContext().VoidTy, fn, FI, args,
|
|
SourceLocation());
|
|
|
|
emitDestroy(addr, type, destroyer, useEHCleanupForArray);
|
|
|
|
FinishFunction();
|
|
|
|
return fn;
|
|
}
|