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llvm-6502/lib/Target/X86/X86MachineFunctionInfo.h
Dan Gohman 61a9213440 Implement an x86-64 ABI detail of passing structs by hidden first
argument. The x86-64 ABI requires the incoming value of %rdi to
be copied to %rax on exit from a function that is returning a
large C struct.

Also, add a README-X86-64 entry detailing the missed optimization
opportunity and proposing an alternative approach.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50075 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-21 23:59:07 +00:00

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4.1 KiB
C++

//====- X86MachineFuctionInfo.h - X86 machine function info -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares X86-specific per-machine-function information.
//
//===----------------------------------------------------------------------===//
#ifndef X86MACHINEFUNCTIONINFO_H
#define X86MACHINEFUNCTIONINFO_H
#include "llvm/CodeGen/MachineFunction.h"
namespace llvm {
enum NameDecorationStyle {
None,
StdCall,
FastCall
};
/// X86MachineFunctionInfo - This class is derived from MachineFunction private
/// X86 target-specific information for each MachineFunction.
class X86MachineFunctionInfo : public MachineFunctionInfo {
/// ForceFramePointer - True if the function is required to use of frame
/// pointer for reasons other than it containing dynamic allocation or
/// that FP eliminatation is turned off. For example, Cygwin main function
/// contains stack pointer re-alignment code which requires FP.
bool ForceFramePointer;
/// CalleeSavedFrameSize - Size of the callee-saved register portion of the
/// stack frame in bytes.
unsigned CalleeSavedFrameSize;
/// BytesToPopOnReturn - Number of bytes function pops on return.
/// Used on windows platform for stdcall & fastcall name decoration
unsigned BytesToPopOnReturn;
/// DecorationStyle - If the function requires additional name decoration,
/// DecorationStyle holds the right way to do so.
NameDecorationStyle DecorationStyle;
/// ReturnAddrIndex - FrameIndex for return slot.
int ReturnAddrIndex;
/// TailCallReturnAddrDelta - Delta the ReturnAddr stack slot is moved
/// Used for creating an area before the register spill area on the stack
/// the returnaddr can be savely move to this area
int TailCallReturnAddrDelta;
/// SRetReturnReg - Some subtargets require that sret lowering includes
/// returning the value of the returned struct in a register. This field
/// holds the virtual register into which the sret argument is passed.
unsigned SRetReturnReg;
public:
X86MachineFunctionInfo() : ForceFramePointer(false),
CalleeSavedFrameSize(0),
BytesToPopOnReturn(0),
DecorationStyle(None),
ReturnAddrIndex(0),
TailCallReturnAddrDelta(0),
SRetReturnReg(0) {}
X86MachineFunctionInfo(MachineFunction &MF) : ForceFramePointer(false),
CalleeSavedFrameSize(0),
BytesToPopOnReturn(0),
DecorationStyle(None),
ReturnAddrIndex(0),
TailCallReturnAddrDelta(0),
SRetReturnReg(0) {}
bool getForceFramePointer() const { return ForceFramePointer;}
void setForceFramePointer(bool forceFP) { ForceFramePointer = forceFP; }
unsigned getCalleeSavedFrameSize() const { return CalleeSavedFrameSize; }
void setCalleeSavedFrameSize(unsigned bytes) { CalleeSavedFrameSize = bytes; }
unsigned getBytesToPopOnReturn() const { return BytesToPopOnReturn; }
void setBytesToPopOnReturn (unsigned bytes) { BytesToPopOnReturn = bytes;}
NameDecorationStyle getDecorationStyle() const { return DecorationStyle; }
void setDecorationStyle(NameDecorationStyle style) { DecorationStyle = style;}
int getRAIndex() const { return ReturnAddrIndex; }
void setRAIndex(int Index) { ReturnAddrIndex = Index; }
int getTCReturnAddrDelta() const { return TailCallReturnAddrDelta; }
void setTCReturnAddrDelta(int delta) {TailCallReturnAddrDelta = delta;}
unsigned getSRetReturnReg() const { return SRetReturnReg; }
void setSRetReturnReg(unsigned Reg) { SRetReturnReg = Reg; }
};
} // End llvm namespace
#endif