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-rw-r--r--clang/lib/CodeGen/CGDeclCXX.cpp464
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diff --git a/clang/lib/CodeGen/CGDeclCXX.cpp b/clang/lib/CodeGen/CGDeclCXX.cpp
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+++ b/clang/lib/CodeGen/CGDeclCXX.cpp
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+//===--- 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 "CGObjCRuntime.h"
+#include "CGCXXABI.h"
+#include "clang/Frontend/CodeGenOptions.h"
+#include "llvm/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);
+ }
+
+ CGF.EmitCXXGlobalDtorRegistration(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);
+}
+
+/// Register a global destructor using __cxa_atexit.
+static void emitGlobalDtorWithCXAAtExit(CodeGenFunction &CGF,
+ llvm::Constant *dtor,
+ llvm::Constant *addr) {
+ // We're assuming that the destructor function is something we can
+ // reasonably call with the default CC. Go ahead and cast it to the
+ // right prototype.
+ llvm::Type *dtorTy =
+ llvm::FunctionType::get(CGF.VoidTy, CGF.Int8PtrTy, false)->getPointerTo();
+
+ // extern "C" int __cxa_atexit(void (*f)(void *), void *p, void *d);
+ llvm::Type *paramTys[] = { dtorTy, CGF.Int8PtrTy, CGF.Int8PtrTy };
+ llvm::FunctionType *atexitTy =
+ llvm::FunctionType::get(CGF.IntTy, paramTys, false);
+
+ // Fetch the actual function.
+ llvm::Constant *atexit =
+ CGF.CGM.CreateRuntimeFunction(atexitTy, "__cxa_atexit");
+ if (llvm::Function *fn = dyn_cast<llvm::Function>(atexit))
+ fn->setDoesNotThrow();
+
+ // Create a variable that binds the atexit to this shared object.
+ llvm::Constant *handle =
+ CGF.CGM.CreateRuntimeVariable(CGF.Int8Ty, "__dso_handle");
+
+ llvm::Value *args[] = {
+ llvm::ConstantExpr::getBitCast(dtor, dtorTy),
+ llvm::ConstantExpr::getBitCast(addr, CGF.Int8PtrTy),
+ handle
+ };
+ CGF.Builder.CreateCall(atexit, args);
+}
+
+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);
+
+ 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 atexit.
+static void emitGlobalDtorWithAtExit(CodeGenFunction &CGF,
+ llvm::Constant *dtor,
+ llvm::Constant *addr) {
+ // Create a function which calls the destructor.
+ llvm::Constant *dtorStub = createAtExitStub(CGF.CGM, dtor, addr);
+
+ // extern "C" int atexit(void (*f)(void));
+ llvm::FunctionType *atexitTy =
+ llvm::FunctionType::get(CGF.IntTy, dtorStub->getType(), false);
+
+ llvm::Constant *atexit =
+ CGF.CGM.CreateRuntimeFunction(atexitTy, "atexit");
+ if (llvm::Function *atexitFn = dyn_cast<llvm::Function>(atexit))
+ atexitFn->setDoesNotThrow();
+
+ CGF.Builder.CreateCall(atexit, dtorStub);
+}
+
+void CodeGenFunction::EmitCXXGlobalDtorRegistration(llvm::Constant *dtor,
+ llvm::Constant *addr) {
+ // Use __cxa_atexit if available.
+ if (CGM.getCodeGenOpts().CXAAtExit) {
+ emitGlobalDtorWithCXAAtExit(*this, dtor, addr);
+ return;
+ }
+
+ // In Apple kexts, we want to add a global destructor entry.
+ // FIXME: shouldn't this be guarded by some variable?
+ if (CGM.getContext().getLangOpts().AppleKext) {
+ // Generate a global destructor entry.
+ CGM.AddCXXDtorEntry(dtor, addr);
+ return;
+ }
+
+ // Otherwise, we just use atexit.
+ emitGlobalDtorWithAtExit(*this, dtor, addr);
+}
+
+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.getContext().getLangOpts().AppleKext) {
+ // Set the section if needed.
+ if (const char *Section =
+ CGM.getContext().getTargetInfo().getStaticInitSectionSpecifier())
+ Fn->setSection(Section);
+ }
+
+ if (!CGM.getLangOpts().Exceptions)
+ Fn->setDoesNotThrow();
+
+ 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.
+ llvm::Function *Fn =
+ CreateGlobalInitOrDestructFunction(*this, FTy, "_GLOBAL__I_a");
+
+ if (!PrioritizedCXXGlobalInits.empty()) {
+ SmallVector<llvm::Constant*, 8> LocalCXXGlobalInits;
+ llvm::array_pod_sort(PrioritizedCXXGlobalInits.begin(),
+ PrioritizedCXXGlobalInits.end());
+ for (unsigned i = 0; i < PrioritizedCXXGlobalInits.size(); i++) {
+ llvm::Function *Fn = PrioritizedCXXGlobalInits[i].second;
+ LocalCXXGlobalInits.push_back(Fn);
+ }
+ LocalCXXGlobalInits.append(CXXGlobalInits.begin(), CXXGlobalInits.end());
+ CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn,
+ &LocalCXXGlobalInits[0],
+ LocalCXXGlobalInits.size());
+ }
+ else
+ 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) {
+ StartFunction(GlobalDecl(), getContext().VoidTy, Fn,
+ getTypes().arrangeNullaryFunction(),
+ FunctionArgList(), SourceLocation());
+
+ // 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) {
+ 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) {
+ 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");
+
+ StartFunction(GlobalDecl(), getContext().VoidTy, fn, FI, args,
+ SourceLocation());
+
+ emitDestroy(addr, type, destroyer, useEHCleanupForArray);
+
+ FinishFunction();
+
+ return fn;
+}