path: root/lib/CodeGen/CGCXX.cpp

//===--- CGDecl.cpp - Emit LLVM Code for 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 C++ code generation.
//
//===----------------------------------------------------------------------===//

// We might split this into multiple files if it gets too unwieldy 

#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "Mangle.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/RecordLayout.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclObjC.h"
#include "llvm/ADT/StringExtras.h"
using namespace clang;
using namespace CodeGen;

void 
CodeGenFunction::EmitCXXGlobalDtorRegistration(const CXXDestructorDecl *Dtor,
                                               llvm::Constant *DeclPtr) {
  // FIXME: This is ABI dependent and we use the Itanium ABI.
  
  const llvm::Type *Int8PtrTy = 
    llvm::PointerType::getUnqual(llvm::Type::Int8Ty);
  
  std::vector<const llvm::Type *> Params;
  Params.push_back(Int8PtrTy);
  
  // Get the destructor function type
  const llvm::Type *DtorFnTy = 
    llvm::FunctionType::get(llvm::Type::VoidTy, Params, false);
  DtorFnTy = llvm::PointerType::getUnqual(DtorFnTy);
  
  Params.clear();
  Params.push_back(DtorFnTy);
  Params.push_back(Int8PtrTy);
  Params.push_back(Int8PtrTy);
  
  // Get the __cxa_atexit function type
  // extern "C" int __cxa_atexit ( void (*f)(void *), void *p, void *d );
  const llvm::FunctionType *AtExitFnTy = 
    llvm::FunctionType::get(ConvertType(getContext().IntTy), Params, false);
  
  llvm::Constant *AtExitFn = CGM.CreateRuntimeFunction(AtExitFnTy,
                                                       "__cxa_atexit");
          
  llvm::Constant *Handle = CGM.CreateRuntimeVariable(Int8PtrTy,
                                                     "__dso_handle");
  
  llvm::Constant *DtorFn = CGM.GetAddrOfCXXDestructor(Dtor, Dtor_Complete);
  
  llvm::Value *Args[3] = { llvm::ConstantExpr::getBitCast(DtorFn, DtorFnTy),
                           llvm::ConstantExpr::getBitCast(DeclPtr, Int8PtrTy),
                           llvm::ConstantExpr::getBitCast(Handle, Int8PtrTy) };
  Builder.CreateCall(AtExitFn, &Args[0], llvm::array_endof(Args));
}

void CodeGenFunction::EmitCXXGlobalVarDeclInit(const VarDecl &D, 
                                               llvm::Constant *DeclPtr) {
  assert(D.hasGlobalStorage() &&
         "VarDecl must have global storage!");
  
  const Expr *Init = D.getInit();
  QualType T = D.getType();
  
  if (T->isReferenceType()) {
    ErrorUnsupported(Init, "Global variable that binds to a reference");
  } else if (!hasAggregateLLVMType(T)) {
    llvm::Value *V = EmitScalarExpr(Init);
    EmitStoreOfScalar(V, DeclPtr, T.isVolatileQualified(), T);
  } else if (T->isAnyComplexType()) {
    EmitComplexExprIntoAddr(Init, DeclPtr, T.isVolatileQualified());
  } else {
    EmitAggExpr(Init, DeclPtr, T.isVolatileQualified());
    
    if (const RecordType *RT = T->getAs<RecordType>()) {
      CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
      if (!RD->hasTrivialDestructor())
        EmitCXXGlobalDtorRegistration(RD->getDestructor(getContext()), DeclPtr);
    }
  }
}

void
CodeGenModule::EmitCXXGlobalInitFunc() {
  if (CXXGlobalInits.empty())
    return;
  
  const llvm::FunctionType *FTy = llvm::FunctionType::get(llvm::Type::VoidTy,
                                                          false);
  
  // Create our global initialization function.
  // FIXME: Should this be tweakable by targets?
  llvm::Function *Fn = 
    llvm::Function::Create(FTy, llvm::GlobalValue::InternalLinkage,
                           "__cxx_global_initialization", &TheModule);
 
  CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn,
                                                   CXXGlobalInits.data(),
                                                   CXXGlobalInits.size());
  AddGlobalCtor(Fn);
}

void CodeGenFunction::GenerateCXXGlobalInitFunc(llvm::Function *Fn,
                                                const VarDecl **Decls,
                                                unsigned NumDecls) {
  StartFunction(0, getContext().VoidTy, Fn, FunctionArgList(), 
                SourceLocation());
  
  for (unsigned i = 0; i != NumDecls; ++i) {
    const VarDecl *D = Decls[i];
    
    llvm::Constant *DeclPtr = CGM.GetAddrOfGlobalVar(D);
    EmitCXXGlobalVarDeclInit(*D, DeclPtr);
  }
  FinishFunction();
}

void 
CodeGenFunction::EmitStaticCXXBlockVarDeclInit(const VarDecl &