llvm/lib/Target/X86/X86MachineFunctionInfo.h
Reid Kleckner 9436574d1b musttail: Forward regparms of variadic functions on x86_64
Summary:
If a variadic function body contains a musttail call, then we copy all
of the remaining register parameters into virtual registers in the
function prologue. We track the virtual registers through the function
body, and add them as additional registers to pass to the call. Because
this is all done in virtual registers, the register allocator usually
gives us good code. If the function does a call, however, it will have
to spill and reload all argument registers (ew).

Forwarding regparms on x86_32 is not implemented because most compilers
don't support varargs in 32-bit with regparms.

Reviewers: majnemer

Subscribers: aemerson, llvm-commits

Differential Revision: http://reviews.llvm.org/D5060

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216780 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-29 21:42:08 +00:00

167 lines
6.3 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 LLVM_LIB_TARGET_X86_X86MACHINEFUNCTIONINFO_H
#define LLVM_LIB_TARGET_X86_X86MACHINEFUNCTIONINFO_H
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineValueType.h"
#include <vector>
namespace llvm {
/// X86MachineFunctionInfo - This class is derived from MachineFunction and
/// contains private X86 target-specific information for each MachineFunction.
class X86MachineFunctionInfo : public MachineFunctionInfo {
virtual void anchor();
/// 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 (in addition
/// to the space used by the return address).
/// Used on windows platform for stdcall & fastcall name decoration
unsigned BytesToPopOnReturn;
/// ReturnAddrIndex - FrameIndex for return slot.
int ReturnAddrIndex;
/// TailCallReturnAddrDelta - The number of bytes by which return address
/// stack slot is moved as the result of tail call optimization.
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;
/// GlobalBaseReg - keeps track of the virtual register initialized for
/// use as the global base register. This is used for PIC in some PIC
/// relocation models.
unsigned GlobalBaseReg;
/// VarArgsFrameIndex - FrameIndex for start of varargs area.
int VarArgsFrameIndex;
/// RegSaveFrameIndex - X86-64 vararg func register save area.
int RegSaveFrameIndex;
/// VarArgsGPOffset - X86-64 vararg func int reg offset.
unsigned VarArgsGPOffset;
/// VarArgsFPOffset - X86-64 vararg func fp reg offset.
unsigned VarArgsFPOffset;
/// ArgumentStackSize - The number of bytes on stack consumed by the arguments
/// being passed on the stack.
unsigned ArgumentStackSize;
/// NumLocalDynamics - Number of local-dynamic TLS accesses.
unsigned NumLocalDynamics;
public:
/// Describes a register that needs to be forwarded from the prologue to a
/// musttail call.
struct Forward {
Forward(unsigned VReg, MCPhysReg PReg, MVT VT)
: VReg(VReg), PReg(PReg), VT(VT) {}
unsigned VReg;
MCPhysReg PReg;
MVT VT;
};
private:
/// ForwardedMustTailRegParms - A list of virtual and physical registers
/// that must be forwarded to every musttail call.
std::vector<Forward> ForwardedMustTailRegParms;
public:
X86MachineFunctionInfo() : ForceFramePointer(false),
CalleeSavedFrameSize(0),
BytesToPopOnReturn(0),
ReturnAddrIndex(0),
TailCallReturnAddrDelta(0),
SRetReturnReg(0),
GlobalBaseReg(0),
VarArgsFrameIndex(0),
RegSaveFrameIndex(0),
VarArgsGPOffset(0),
VarArgsFPOffset(0),
ArgumentStackSize(0),
NumLocalDynamics(0) {}
explicit X86MachineFunctionInfo(MachineFunction &MF)
: ForceFramePointer(false),
CalleeSavedFrameSize(0),
BytesToPopOnReturn(0),
ReturnAddrIndex(0),
TailCallReturnAddrDelta(0),
SRetReturnReg(0),
GlobalBaseReg(0),
VarArgsFrameIndex(0),
RegSaveFrameIndex(0),
VarArgsGPOffset(0),
VarArgsFPOffset(0),
ArgumentStackSize(0),
NumLocalDynamics(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;}
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; }
unsigned getGlobalBaseReg() const { return GlobalBaseReg; }
void setGlobalBaseReg(unsigned Reg) { GlobalBaseReg = Reg; }
int getVarArgsFrameIndex() const { return VarArgsFrameIndex; }
void setVarArgsFrameIndex(int Idx) { VarArgsFrameIndex = Idx; }
int getRegSaveFrameIndex() const { return RegSaveFrameIndex; }
void setRegSaveFrameIndex(int Idx) { RegSaveFrameIndex = Idx; }
unsigned getVarArgsGPOffset() const { return VarArgsGPOffset; }
void setVarArgsGPOffset(unsigned Offset) { VarArgsGPOffset = Offset; }
unsigned getVarArgsFPOffset() const { return VarArgsFPOffset; }
void setVarArgsFPOffset(unsigned Offset) { VarArgsFPOffset = Offset; }
unsigned getArgumentStackSize() const { return ArgumentStackSize; }
void setArgumentStackSize(unsigned size) { ArgumentStackSize = size; }
unsigned getNumLocalDynamicTLSAccesses() const { return NumLocalDynamics; }
void incNumLocalDynamicTLSAccesses() { ++NumLocalDynamics; }
std::vector<Forward> &getForwardedMustTailRegParms() {
return ForwardedMustTailRegParms;
}
};
} // End llvm namespace
#endif