path: root/lib/CodeGen/CGCall.cpp

//===----- CGCall.h - Encapsulate calling convention details ----*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// These classes wrap the information about a call or function
// definition used to handle ABI compliancy.
//
//===----------------------------------------------------------------------===//

#include "CGCall.h"
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclObjC.h"
#include "clang/Frontend/CodeGenOptions.h"
#include "llvm/Attributes.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Target/TargetData.h"

#include "ABIInfo.h"

using namespace clang;
using namespace CodeGen;

/***/

// FIXME: Use iterator and sidestep silly type array creation.

static unsigned ClangCallConvToLLVMCallConv(CallingConv CC) {
  switch (CC) {
  default: return llvm::CallingConv::C;
  case CC_X86StdCall: return llvm::CallingConv::X86_StdCall;
  case CC_X86FastCall: return llvm::CallingConv::X86_FastCall;
  case CC_X86ThisCall: return llvm::CallingConv::X86_ThisCall;
  }
}

/// Derives the 'this' type for codegen purposes, i.e. ignoring method
/// qualification.
/// FIXME: address space qualification?
static CanQualType GetThisType(ASTContext &Context, const CXXRecordDecl *RD) {
  QualType RecTy = Context.getTagDeclType(RD)->getCanonicalTypeInternal();
  return Context.getPointerType(CanQualType::CreateUnsafe(RecTy));
}

/// Returns the canonical formal type of the given C++ method.
static CanQual<FunctionProtoType> GetFormalType(const CXXMethodDecl *MD) {
  return MD->getType()->getCanonicalTypeUnqualified()
           .getAs<FunctionProtoType>();
}

/// Returns the "extra-canonicalized" return type, which discards
/// qualifiers on the return type.  Codegen doesn't care about them,
/// and it makes ABI code a little easier to be able to assume that
/// all parameter and return types are top-level unqualified.
static CanQualType GetReturnType(QualType RetTy) {
  return RetTy->getCanonicalTypeUnqualified().getUnqualifiedType();
}

const CGFunctionInfo &
CodeGenTypes::getFunctionInfo(CanQual<FunctionNoProtoType> FTNP) {
  return getFunctionInfo(FTNP->getResultType().getUnqualifiedType(),
                         llvm::SmallVector<CanQualType, 16>(),
                         FTNP->getExtInfo());
}

/// \param Args - contains any initial parameters besides those
///   in the formal type
static const CGFunctionInfo &getFunctionInfo(CodeGenTypes &CGT,
                                  llvm::SmallVectorImpl<CanQualType> &ArgTys,
                                             CanQual<FunctionProtoType> FTP) {
  // FIXME: Kill copy.
  for (unsigned i = 0, e = FTP->getNumArgs(); i != e; ++i)
    ArgTys.push_back(FTP->getArgType(i));
  CanQualType ResTy = FTP->getResultType().getUnqualifiedType();
  return CGT.getFunctionInfo(ResTy, ArgTys,
                             FTP->getExtInfo());
}

const CGFunctionInfo &
CodeGenTypes::getFunctionInfo(CanQual<FunctionProtoType> FTP) {
  llvm::SmallVector<CanQualType, 16> ArgTys;
  return ::getFunctionInfo(*this, ArgTys, FTP);
}

static CallingConv getCallingConventionForDecl(const Decl *D) {
  // Set the appropriate calling convention for the Function.
  if (D->hasAttr<StdCallAttr>())
    return CC_X86StdCall;

  if (D->hasAttr<FastCallAttr>())
    return CC_X86FastCall;

  if (D->hasAttr<ThisCallAttr>())
    return CC_X86ThisCall;

  return CC_C;
}

const CGFunctionInfo &CodeGenTypes::getFunctionInfo(const CXXRecordDecl *RD,
                                                 const FunctionProtoType *FTP) {
  llvm::SmallVector<CanQualType, 16> ArgTys;

  // Add the 'this' pointer.
  ArgTys.push_back(GetThisType(Context, RD));

  return ::getFunctionInfo(*this, ArgTys,
              FTP->getCanonicalTypeUnqualified().getAs<FunctionProtoType>());
}

const CGFunctionInfo &CodeGenTypes::getFunctionInfo(const CXXMethodDecl *MD) {
  llvm::SmallVector<CanQualType, 16>