llvm/lib/CodeGen/TargetFrameLoweringImpl.cpp
Michael Kuperstein acd5f13c88 [X86] Convert esp-relative movs of function arguments to pushes, step 2
This moves the transformation introduced in r223757 into a separate MI pass.
This allows it to cover many more cases (not only cases where there must be a 
reserved call frame), and perform rudimentary call folding. It still doesn't 
have a heuristic, so it is enabled only for optsize/minsize, with stack 
alignment <= 8, where it ought to be a fairly clear win.

(Re-commit of r227728)

Differential Revision: http://reviews.llvm.org/D6789


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227752 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-01 16:56:04 +00:00

50 lines
1.9 KiB
C++

//===----- TargetFrameLoweringImpl.cpp - Implement target frame interface --==//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Implements the layout of a stack frame on the target machine.
//
//===----------------------------------------------------------------------===//
#include "llvm/Target/TargetFrameLowering.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetSubtargetInfo.h"
#include <cstdlib>
using namespace llvm;
TargetFrameLowering::~TargetFrameLowering() {
}
/// getFrameIndexOffset - Returns the displacement from the frame register to
/// the stack frame of the specified index. This is the default implementation
/// which is overridden for some targets.
int TargetFrameLowering::getFrameIndexOffset(const MachineFunction &MF,
int FI) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
return MFI->getObjectOffset(FI) + MFI->getStackSize() -
getOffsetOfLocalArea() + MFI->getOffsetAdjustment();
}
int TargetFrameLowering::getFrameIndexReference(const MachineFunction &MF,
int FI, unsigned &FrameReg) const {
const TargetRegisterInfo *RI = MF.getSubtarget().getRegisterInfo();
// By default, assume all frame indices are referenced via whatever
// getFrameRegister() says. The target can override this if it's doing
// something different.
FrameReg = RI->getFrameRegister(MF);
return getFrameIndexOffset(MF, FI);
}
bool TargetFrameLowering::needsFrameIndexResolution(
const MachineFunction &MF) const {
return MF.getFrameInfo()->hasStackObjects();
}