forked from OSchip/llvm-project
358 lines
13 KiB
C++
358 lines
13 KiB
C++
//===--- CGDeclCXX.cpp - Emit LLVM Code for C++ declarations --------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This contains code dealing with code generation of C++ declarations
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//
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//===----------------------------------------------------------------------===//
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#include "CodeGenFunction.h"
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#include "CGObjCRuntime.h"
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#include "CGCXXABI.h"
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#include "clang/Frontend/CodeGenOptions.h"
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#include "llvm/Intrinsics.h"
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using namespace clang;
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using namespace CodeGen;
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static void EmitDeclInit(CodeGenFunction &CGF, const VarDecl &D,
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llvm::Constant *DeclPtr) {
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assert(D.hasGlobalStorage() && "VarDecl must have global storage!");
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assert(!D.getType()->isReferenceType() &&
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"Should not call EmitDeclInit on a reference!");
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ASTContext &Context = CGF.getContext();
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const Expr *Init = D.getInit();
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QualType T = D.getType();
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bool isVolatile = Context.getCanonicalType(T).isVolatileQualified();
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unsigned Alignment = Context.getDeclAlign(&D).getQuantity();
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if (!CGF.hasAggregateLLVMType(T)) {
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llvm::Value *V = CGF.EmitScalarExpr(Init);
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CodeGenModule &CGM = CGF.CGM;
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Qualifiers::GC GCAttr = CGM.getContext().getObjCGCAttrKind(T);
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if (GCAttr == Qualifiers::Strong)
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CGM.getObjCRuntime().EmitObjCGlobalAssign(CGF, V, DeclPtr,
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D.isThreadSpecified());
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else if (GCAttr == Qualifiers::Weak)
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CGM.getObjCRuntime().EmitObjCWeakAssign(CGF, V, DeclPtr);
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else
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CGF.EmitStoreOfScalar(V, DeclPtr, isVolatile, Alignment, T);
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} else if (T->isAnyComplexType()) {
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CGF.EmitComplexExprIntoAddr(Init, DeclPtr, isVolatile);
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} else {
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CGF.EmitAggExpr(Init, AggValueSlot::forAddr(DeclPtr, isVolatile, true));
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}
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}
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/// Emit code to cause the destruction of the given variable with
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/// static storage duration.
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static void EmitDeclDestroy(CodeGenFunction &CGF, const VarDecl &D,
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llvm::Constant *DeclPtr) {
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CodeGenModule &CGM = CGF.CGM;
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ASTContext &Context = CGF.getContext();
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QualType T = D.getType();
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// Drill down past array types.
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const ConstantArrayType *Array = Context.getAsConstantArrayType(T);
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if (Array)
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T = Context.getBaseElementType(Array);
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/// If that's not a record, we're done.
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/// FIXME: __attribute__((cleanup)) ?
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const RecordType *RT = T->getAs<RecordType>();
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if (!RT)
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return;
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CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
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if (RD->hasTrivialDestructor())
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return;
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CXXDestructorDecl *Dtor = RD->getDestructor();
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llvm::Constant *DtorFn;
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if (Array) {
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DtorFn =
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CodeGenFunction(CGM).GenerateCXXAggrDestructorHelper(Dtor, Array,
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DeclPtr);
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const llvm::Type *Int8PtrTy =
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llvm::Type::getInt8PtrTy(CGM.getLLVMContext());
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DeclPtr = llvm::Constant::getNullValue(Int8PtrTy);
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} else
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DtorFn = CGM.GetAddrOfCXXDestructor(Dtor, Dtor_Complete);
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CGF.EmitCXXGlobalDtorRegistration(DtorFn, DeclPtr);
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}
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void CodeGenFunction::EmitCXXGlobalVarDeclInit(const VarDecl &D,
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llvm::Constant *DeclPtr) {
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const Expr *Init = D.getInit();
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QualType T = D.getType();
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if (!T->isReferenceType()) {
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EmitDeclInit(*this, D, DeclPtr);
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EmitDeclDestroy(*this, D, DeclPtr);
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return;
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}
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unsigned Alignment = getContext().getDeclAlign(&D).getQuantity();
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RValue RV = EmitReferenceBindingToExpr(Init, &D);
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EmitStoreOfScalar(RV.getScalarVal(), DeclPtr, false, Alignment, T);
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}
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void
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CodeGenFunction::EmitCXXGlobalDtorRegistration(llvm::Constant *DtorFn,
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llvm::Constant *DeclPtr) {
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// Generate a global destructor entry if not using __cxa_atexit.
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if (!CGM.getCodeGenOpts().CXAAtExit) {
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CGM.AddCXXDtorEntry(DtorFn, DeclPtr);
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return;
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}
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std::vector<const llvm::Type *> Params;
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Params.push_back(Int8PtrTy);
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// Get the destructor function type
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const llvm::Type *DtorFnTy =
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llvm::FunctionType::get(llvm::Type::getVoidTy(getLLVMContext()),
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Params, false);
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DtorFnTy = llvm::PointerType::getUnqual(DtorFnTy);
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Params.clear();
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Params.push_back(DtorFnTy);
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Params.push_back(Int8PtrTy);
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Params.push_back(Int8PtrTy);
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// Get the __cxa_atexit function type
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// extern "C" int __cxa_atexit ( void (*f)(void *), void *p, void *d );
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const llvm::FunctionType *AtExitFnTy =
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llvm::FunctionType::get(ConvertType(getContext().IntTy), Params, false);
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llvm::Constant *AtExitFn = CGM.CreateRuntimeFunction(AtExitFnTy,
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"__cxa_atexit");
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if (llvm::Function *Fn = dyn_cast<llvm::Function>(AtExitFn))
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Fn->setDoesNotThrow();
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llvm::Constant *Handle = CGM.CreateRuntimeVariable(Int8PtrTy,
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"__dso_handle");
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llvm::Value *Args[3] = { llvm::ConstantExpr::getBitCast(DtorFn, DtorFnTy),
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llvm::ConstantExpr::getBitCast(DeclPtr, Int8PtrTy),
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llvm::ConstantExpr::getBitCast(Handle, Int8PtrTy) };
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Builder.CreateCall(AtExitFn, &Args[0], llvm::array_endof(Args));
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}
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void CodeGenFunction::EmitCXXGuardedInit(const VarDecl &D,
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llvm::GlobalVariable *DeclPtr) {
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// If we've been asked to forbid guard variables, emit an error now.
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// This diagnostic is hard-coded for Darwin's use case; we can find
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// better phrasing if someone else needs it.
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if (CGM.getCodeGenOpts().ForbidGuardVariables)
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CGM.Error(D.getLocation(),
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"this initialization requires a guard variable, which "
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"the kernel does not support");
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CGM.getCXXABI().EmitGuardedInit(*this, D, DeclPtr);
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}
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static llvm::Function *
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CreateGlobalInitOrDestructFunction(CodeGenModule &CGM,
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const llvm::FunctionType *FTy,
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llvm::StringRef Name) {
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llvm::Function *Fn =
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llvm::Function::Create(FTy, llvm::GlobalValue::InternalLinkage,
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Name, &CGM.getModule());
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if (!CGM.getContext().getLangOptions().AppleKext) {
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// Set the section if needed.
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if (const char *Section =
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CGM.getContext().Target.getStaticInitSectionSpecifier())
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Fn->setSection(Section);
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}
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if (!CGM.getLangOptions().Exceptions)
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Fn->setDoesNotThrow();
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return Fn;
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}
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void
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CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
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llvm::GlobalVariable *Addr) {
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const llvm::FunctionType *FTy
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= llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext),
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false);
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// Create a variable initialization function.
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llvm::Function *Fn =
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CreateGlobalInitOrDestructFunction(*this, FTy, "__cxx_global_var_init");
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CodeGenFunction(*this).GenerateCXXGlobalVarDeclInitFunc(Fn, D, Addr);
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if (D->hasAttr<InitPriorityAttr>()) {
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unsigned int order = D->getAttr<InitPriorityAttr>()->getPriority();
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OrderGlobalInits Key(order, PrioritizedCXXGlobalInits.size());
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PrioritizedCXXGlobalInits.push_back(std::make_pair(Key, Fn));
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DelayedCXXInitPosition.erase(D);
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}
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else {
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llvm::DenseMap<const Decl *, unsigned>::iterator I =
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DelayedCXXInitPosition.find(D);
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if (I == DelayedCXXInitPosition.end()) {
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CXXGlobalInits.push_back(Fn);
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} else {
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assert(CXXGlobalInits[I->second] == 0);
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CXXGlobalInits[I->second] = Fn;
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DelayedCXXInitPosition.erase(I);
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}
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}
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}
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void
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CodeGenModule::EmitCXXGlobalInitFunc() {
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while (!CXXGlobalInits.empty() && !CXXGlobalInits.back())
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CXXGlobalInits.pop_back();
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if (CXXGlobalInits.empty() && PrioritizedCXXGlobalInits.empty())
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return;
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const llvm::FunctionType *FTy
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= llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext),
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false);
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// Create our global initialization function.
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llvm::Function *Fn =
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CreateGlobalInitOrDestructFunction(*this, FTy, "_GLOBAL__I_a");
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if (!PrioritizedCXXGlobalInits.empty()) {
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llvm::SmallVector<llvm::Constant*, 8> LocalCXXGlobalInits;
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llvm::array_pod_sort(PrioritizedCXXGlobalInits.begin(),
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PrioritizedCXXGlobalInits.end());
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for (unsigned i = 0; i < PrioritizedCXXGlobalInits.size(); i++) {
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llvm::Function *Fn = PrioritizedCXXGlobalInits[i].second;
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LocalCXXGlobalInits.push_back(Fn);
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}
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LocalCXXGlobalInits.append(CXXGlobalInits.begin(), CXXGlobalInits.end());
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CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn,
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&LocalCXXGlobalInits[0],
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LocalCXXGlobalInits.size());
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}
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else
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CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn,
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&CXXGlobalInits[0],
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CXXGlobalInits.size());
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AddGlobalCtor(Fn);
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CXXGlobalInits.clear();
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PrioritizedCXXGlobalInits.clear();
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}
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void CodeGenModule::EmitCXXGlobalDtorFunc() {
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if (CXXGlobalDtors.empty())
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return;
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const llvm::FunctionType *FTy
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= llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext),
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false);
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// Create our global destructor function.
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llvm::Function *Fn =
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CreateGlobalInitOrDestructFunction(*this, FTy, "_GLOBAL__D_a");
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CodeGenFunction(*this).GenerateCXXGlobalDtorFunc(Fn, CXXGlobalDtors);
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AddGlobalDtor(Fn);
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}
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/// Emit the code necessary to initialize the given global variable.
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void CodeGenFunction::GenerateCXXGlobalVarDeclInitFunc(llvm::Function *Fn,
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const VarDecl *D,
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llvm::GlobalVariable *Addr) {
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StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
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getTypes().getNullaryFunctionInfo(),
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FunctionArgList(), SourceLocation());
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// Use guarded initialization if the global variable is weak due to
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// being a class template's static data member. These will always
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// have weak_odr linkage.
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if (Addr->getLinkage() == llvm::GlobalValue::WeakODRLinkage &&
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D->isStaticDataMember() &&
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D->getInstantiatedFromStaticDataMember()) {
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EmitCXXGuardedInit(*D, Addr);
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} else {
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EmitCXXGlobalVarDeclInit(*D, Addr);
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}
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FinishFunction();
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}
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void CodeGenFunction::GenerateCXXGlobalInitFunc(llvm::Function *Fn,
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llvm::Constant **Decls,
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unsigned NumDecls) {
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StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
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getTypes().getNullaryFunctionInfo(),
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FunctionArgList(), SourceLocation());
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for (unsigned i = 0; i != NumDecls; ++i)
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if (Decls[i])
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Builder.CreateCall(Decls[i]);
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FinishFunction();
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}
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void CodeGenFunction::GenerateCXXGlobalDtorFunc(llvm::Function *Fn,
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const std::vector<std::pair<llvm::WeakVH, llvm::Constant*> >
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&DtorsAndObjects) {
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StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
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getTypes().getNullaryFunctionInfo(),
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FunctionArgList(), SourceLocation());
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// Emit the dtors, in reverse order from construction.
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for (unsigned i = 0, e = DtorsAndObjects.size(); i != e; ++i) {
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llvm::Value *Callee = DtorsAndObjects[e - i - 1].first;
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llvm::CallInst *CI = Builder.CreateCall(Callee,
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DtorsAndObjects[e - i - 1].second);
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// Make sure the call and the callee agree on calling convention.
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if (llvm::Function *F = dyn_cast<llvm::Function>(Callee))
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CI->setCallingConv(F->getCallingConv());
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}
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FinishFunction();
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}
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/// GenerateCXXAggrDestructorHelper - Generates a helper function which when
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/// invoked, calls the default destructor on array elements in reverse order of
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/// construction.
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llvm::Function *
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CodeGenFunction::GenerateCXXAggrDestructorHelper(const CXXDestructorDecl *D,
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const ArrayType *Array,
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llvm::Value *This) {
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FunctionArgList args;
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ImplicitParamDecl dst(0, SourceLocation(), 0, getContext().VoidPtrTy);
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args.push_back(&dst);
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const CGFunctionInfo &FI =
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CGM.getTypes().getFunctionInfo(getContext().VoidTy, args,
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FunctionType::ExtInfo());
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const llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(FI, false);
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llvm::Function *Fn =
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CreateGlobalInitOrDestructFunction(CGM, FTy, "__cxx_global_array_dtor");
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StartFunction(GlobalDecl(), getContext().VoidTy, Fn, FI, args,
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SourceLocation());
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QualType BaseElementTy = getContext().getBaseElementType(Array);
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const llvm::Type *BasePtr = ConvertType(BaseElementTy)->getPointerTo();
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llvm::Value *BaseAddrPtr = Builder.CreateBitCast(This, BasePtr);
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EmitCXXAggrDestructorCall(D, Array, BaseAddrPtr);
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FinishFunction();
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return Fn;
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}
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