llvm/lib/CodeGen/TargetFrameLoweringImpl.cpp
Akira Hatanaka 01461204b3 Stop resetting NoFramePointerElim in TargetMachine::resetTargetOptions.
This is part of the work to remove TargetMachine::resetTargetOptions.

In this patch, instead of updating global variable NoFramePointerElim in
resetTargetOptions, its use in DisableFramePointerElim is replaced with a call
to TargetFrameLowering::noFramePointerElim. This function determines on a
per-function basis if frame pointer elimination should be disabled.

There is no change in functionality except that cl:opt option "disable-fp-elim"
can now override function attribute "no-frame-pointer-elim". 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238080 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-23 01:14:08 +00:00

57 lines
2.2 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/IR/Function.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetSubtargetInfo.h"
#include <cstdlib>
using namespace llvm;
TargetFrameLowering::~TargetFrameLowering() {
}
/// The default implementation just looks at attribute "no-frame-pointer-elim".
bool TargetFrameLowering::noFramePointerElim(const MachineFunction &MF) const {
auto Attr = MF.getFunction()->getFnAttribute("no-frame-pointer-elim");
return Attr.getValueAsString() == "true";
}
/// 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();
}