llvm/lib/Target/Sparc/SparcFrameLowering.cpp
2011-01-13 21:28:52 +00:00

81 lines
3.0 KiB
C++

//====- SparcFrameLowering.cpp - Sparc Frame Information -------*- C++ -*-====//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the Sparc implementation of TargetFrameLowering class.
//
//===----------------------------------------------------------------------===//
#include "SparcFrameLowering.h"
#include "SparcInstrInfo.h"
#include "SparcMachineFunctionInfo.h"
#include "llvm/Function.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Support/CommandLine.h"
using namespace llvm;
void SparcFrameLowering::emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front();
MachineFrameInfo *MFI = MF.getFrameInfo();
const SparcInstrInfo &TII =
*static_cast<const SparcInstrInfo*>(MF.getTarget().getInstrInfo());
MachineBasicBlock::iterator MBBI = MBB.begin();
DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
// Get the number of bytes to allocate from the FrameInfo
int NumBytes = (int) MFI->getStackSize();
// Emit the correct save instruction based on the number of bytes in
// the frame. Minimum stack frame size according to V8 ABI is:
// 16 words for register window spill
// 1 word for address of returned aggregate-value
// + 6 words for passing parameters on the stack
// ----------
// 23 words * 4 bytes per word = 92 bytes
NumBytes += 92;
// Round up to next doubleword boundary -- a double-word boundary
// is required by the ABI.
NumBytes = (NumBytes + 7) & ~7;
NumBytes = -NumBytes;
if (NumBytes >= -4096) {
BuildMI(MBB, MBBI, dl, TII.get(SP::SAVEri), SP::O6)
.addReg(SP::O6).addImm(NumBytes);
} else {
// Emit this the hard way. This clobbers G1 which we always know is
// available here.
unsigned OffHi = (unsigned)NumBytes >> 10U;
BuildMI(MBB, MBBI, dl, TII.get(SP::SETHIi), SP::G1).addImm(OffHi);
// Emit G1 = G1 + I6
BuildMI(MBB, MBBI, dl, TII.get(SP::ORri), SP::G1)
.addReg(SP::G1).addImm(NumBytes & ((1 << 10)-1));
BuildMI(MBB, MBBI, dl, TII.get(SP::SAVErr), SP::O6)
.addReg(SP::O6).addReg(SP::G1);
}
}
void SparcFrameLowering::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
const SparcInstrInfo &TII =
*static_cast<const SparcInstrInfo*>(MF.getTarget().getInstrInfo());
DebugLoc dl = MBBI->getDebugLoc();
assert(MBBI->getOpcode() == SP::RETL &&
"Can only put epilog before 'retl' instruction!");
BuildMI(MBB, MBBI, dl, TII.get(SP::RESTORErr), SP::G0).addReg(SP::G0)
.addReg(SP::G0);
}