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Make $fp and $ra callee-saved registers and let PrologEpilogInserter handle

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saving and restoring them.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131745 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Akira Hatanaka
2011-05-20 18:39:33 +00:00
parent f85092c255
commit 17a1e87751
6 changed files with 39 additions and 103 deletions
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110
lib/Target/Mips/MipsFrameLowering.cpp
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@@ -156,26 +156,6 @@ void MipsFrameLowering::adjustMipsStackFrame(MachineFunction &MF) const {
StackOffset += MFI->getObjectAlignment(CSI[i].getFrameIdx());
}
// Stack locations for FP and RA. If only one of them is used,
// the space must be allocated for both, otherwise no space at all.
if (hasFP(MF) || MFI->adjustsStack()) {
// FP stack location
MFI->setObjectOffset(MFI->CreateStackObject(RegSize, RegSize, true),
StackOffset);
MipsFI->setFPStackOffset(StackOffset);
TopCPUSavedRegOff = StackOffset;
StackOffset += RegSize;
// SP stack location
MFI->setObjectOffset(MFI->CreateStackObject(RegSize, RegSize, true),
StackOffset);
MipsFI->setRAStackOffset(StackOffset);
StackOffset += RegSize;
if (MFI->adjustsStack())
TopCPUSavedRegOff += RegSize;
}
StackOffset = ((StackOffset+StackAlign-1)/StackAlign*StackAlign);
// Adjust FPU Callee Saved Registers Area. This Area must be
@@ -267,9 +247,6 @@ void MipsFrameLowering::emitPrologue(MachineFunction &MF) const {
// No need to allocate space on the stack.
if (StackSize == 0 && !MFI->adjustsStack()) return;
int FPOffset = MipsFI->getFPStackOffset();
int RAOffset = MipsFI->getRAStackOffset();
BuildMI(MBB, MBBI, dl, TII.get(Mips::NOREORDER));
// TODO: check need from GP here.
@@ -288,36 +265,11 @@ void MipsFrameLowering::emitPrologue(MachineFunction &MF) const {
if (ATUsed)
BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
// Save the return address only if the function isn't a leaf one.
// sw $ra, stack_loc($sp)
if (MFI->adjustsStack()) {
ATUsed = expandRegLargeImmPair(Mips::SP, RAOffset, NewReg, NewImm, MBB,
MBBI);
BuildMI(MBB, MBBI, dl, TII.get(Mips::SW))
.addReg(Mips::RA).addImm(NewImm).addReg(NewReg);
// FIXME: change this when mips goes MC".
if (ATUsed)
BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
}
// if framepointer enabled, save it and set it
// to point to the stack pointer
if (hasFP(MF)) {
// sw $fp,stack_loc($sp)
ATUsed = expandRegLargeImmPair(Mips::SP, FPOffset, NewReg, NewImm, MBB,
MBBI);
BuildMI(MBB, MBBI, dl, TII.get(Mips::SW))
.addReg(Mips::FP).addImm(NewImm).addReg(NewReg);
// FIXME: change this when mips goes MC".
if (ATUsed)
BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
// if framepointer enabled, set it to point to the stack pointer.
if (hasFP(MF))
// move $fp, $sp
BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDu), Mips::FP)
.addReg(Mips::SP).addReg(Mips::ZERO);
}
// Restore GP from the saved stack location
if (MipsFI->needGPSaveRestore())
@@ -329,7 +281,6 @@ void MipsFrameLowering::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
MachineFrameInfo *MFI = MF.getFrameInfo();
MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
const MipsInstrInfo &TII =
*static_cast<const MipsInstrInfo*>(MF.getTarget().getInstrInfo());
DebugLoc dl = MBBI->getDebugLoc();
@@ -337,45 +288,16 @@ void MipsFrameLowering::emitEpilogue(MachineFunction &MF,
// Get the number of bytes from FrameInfo
int NumBytes = (int) MFI->getStackSize();
// Get the FI's where RA and FP are saved.
int FPOffset = MipsFI->getFPStackOffset();
int RAOffset = MipsFI->getRAStackOffset();
unsigned NewReg = 0;
int NewImm = 0;
bool ATUsed = false;
// if framepointer enabled, restore it and restore the
// stack pointer
if (hasFP(MF)) {
// if framepointer enabled, restore the stack pointer.
if (hasFP(MF))
// move $sp, $fp
BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDu), Mips::SP)
.addReg(Mips::FP).addReg(Mips::ZERO);
// lw $fp,stack_loc($sp)
ATUsed = expandRegLargeImmPair(Mips::SP, FPOffset, NewReg, NewImm, MBB,
MBBI);
BuildMI(MBB, MBBI, dl, TII.get(Mips::LW), Mips::FP)
.addImm(NewImm).addReg(NewReg);
// FIXME: change this when mips goes MC".
if (ATUsed)
BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
}
// Restore the return address only if the function isn't a leaf one.
// lw $ra, stack_loc($sp)
if (MFI->adjustsStack()) {
ATUsed = expandRegLargeImmPair(Mips::SP, RAOffset, NewReg, NewImm, MBB,
MBBI);
BuildMI(MBB, MBBI, dl, TII.get(Mips::LW), Mips::RA)
.addImm(NewImm).addReg(NewReg);
// FIXME: change this when mips goes MC".
if (ATUsed)
BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
}
// adjust stack : insert addi sp, sp, (imm)
if (NumBytes) {
ATUsed = expandRegLargeImmPair(Mips::SP, NumBytes, NewReg, NewImm, MBB,
@@ -389,6 +311,30 @@ void MipsFrameLowering::emitEpilogue(MachineFunction &MF,
}
}
void MipsFrameLowering::
processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
RegScavenger *RS) const {
MachineRegisterInfo& MRI = MF.getRegInfo();
MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
// FIXME: remove this code if register allocator can correctly mark
// $fp and $ra used or unused.
// Mark $fp and $ra as used or unused.
if (hasFP(MF))
MRI.setPhysRegUsed(Mips::FP);
// The register allocator might determine $ra is used after seeing
// instruction "jr $ra", but we do not want PrologEpilogInserter to insert
// instructions to save/restore $ra unless there is a function call.
// To correct this, $ra is explicitly marked unused if there is no
// function call.
if (MipsFI->hasCall())
MRI.setPhysRegUsed(Mips::RA);
else
MRI.setPhysRegUnused(Mips::RA);
}
void MipsFrameLowering::
processFunctionBeforeFrameFinalized(MachineFunction &MF) const {
const MipsRegisterInfo *RegInfo =