-//=======- MipsFrameLowering.cpp - Mips Frame Information ------*- C++ -*-====//
+//=======- MipsFrameLowering.cpp - Mips 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 Mips implementation of TargetFrameLowering class.
//
-//===----------------------------------------------------------------------===//
+//===---------------------------------------------------------------------===//
#include "MipsFrameLowering.h"
#include "MipsInstrInfo.h"
using namespace llvm;
-//===----------------------------------------------------------------------===//
+//===---------------------------------------------------------------------===//
//
// Stack Frame Processing methods
// +----------------------------+
// possible to detect those references and the offsets are adjusted to
// their real location.
//
-//===----------------------------------------------------------------------===//
+//===---------------------------------------------------------------------===//
// hasFP - Return true if the specified function should have a dedicated frame
-// pointer register. This is true if the function has variable sized allocas or
-// if frame pointer elimination is disabled.
+// pointer register. This is true if the function has variable sized allocas
+// or if frame pointer elimination is disabled.
bool MipsFrameLowering::hasFP(const MachineFunction &MF) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
return DisableFramePointerElim(MF) || MFI->hasVarSizedObjects();
MipsFI->setFPUTopSavedRegOff(TopFPUSavedRegOff-StackOffset);
}
+// expand pair of register and immediate if the immediate doesn't fit in the
+// 16-bit offset field.
+// e.g.
+// if OrigImm = 0x10000, OrigReg = $sp:
+// generate the following sequence of instrs:
+// lui $at, hi(0x10000)
+// addu $at, $sp, $at
+//
+// (NewReg, NewImm) = ($at, lo(Ox10000))
+// return true
+static bool expandRegLargeImmPair(unsigned OrigReg, int OrigImm,
+ unsigned& NewReg, int& NewImm,
+ MachineBasicBlock& MBB,
+ MachineBasicBlock::iterator I) {
+ // OrigImm fits in the 16-bit field
+ if (OrigImm < 0x8000 && OrigImm >= -0x8000) {
+ NewReg = OrigReg;
+ NewImm = OrigImm;
+ return false;
+ }
+
+ MachineFunction* MF = MBB.getParent();
+ const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
+ DebugLoc DL = I->getDebugLoc();
+ int ImmLo = OrigImm & 0xffff;
+ int ImmHi = (((unsigned)OrigImm & 0xffff0000) >> 16) +
+ ((OrigImm & 0x8000) != 0);
+
+ // FIXME: change this when mips goes MC".
+ BuildMI(MBB, I, DL, TII->get(Mips::NOAT));
+ BuildMI(MBB, I, DL, TII->get(Mips::LUi), Mips::AT).addImm(ImmHi);
+ BuildMI(MBB, I, DL, TII->get(Mips::ADDu), Mips::AT).addReg(OrigReg)
+ .addReg(Mips::AT);
+ NewReg = Mips::AT;
+ NewImm = ImmLo;
+
+ return true;
+}
+
void MipsFrameLowering::emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front();
MachineFrameInfo *MFI = MF.getFrameInfo();
MachineBasicBlock::iterator MBBI = MBB.begin();
DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
bool isPIC = (MF.getTarget().getRelocationModel() == Reloc::PIC_);
+ unsigned NewReg = 0;
+ int NewImm = 0;
+ bool ATUsed;
// Get the right frame order for Mips.
adjustMipsStackFrame(MF);
BuildMI(MBB, MBBI, dl, TII.get(Mips::NOMACRO));
// Adjust stack : addi sp, sp, (-imm)
+ ATUsed = expandRegLargeImmPair(Mips::SP, -StackSize, NewReg, NewImm, MBB,
+ MBBI);
BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDiu), Mips::SP)
- .addReg(Mips::SP).addImm(-StackSize);
+ .addReg(NewReg).addImm(NewImm);
+
+ // FIXME: change this when mips goes MC".
+ if (ATUsed)
+ BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
- // Save the return address only if the function isnt a leaf one.
+ // 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(RAOffset).addReg(Mips::SP);
+ .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(FPOffset).addReg(Mips::SP);
+ .addReg(Mips::FP).addImm(NewImm).addReg(NewReg);
+
+ // FIXME: change this when mips goes MC".
+ if (ATUsed)
+ BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
// move $fp, $sp
BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDu), Mips::FP)
void MipsFrameLowering::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
- MachineBasicBlock::iterator MBBI = prior(MBB.end());
+ MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
MachineFrameInfo *MFI = MF.getFrameInfo();
MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
const MipsInstrInfo &TII =
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)) {
.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(FPOffset).addReg(Mips::SP);
+ .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 isnt a leaf one.
+ // 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(RAOffset).addReg(Mips::SP);
+ .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,
+ MBBI);
BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDiu), Mips::SP)
- .addReg(Mips::SP).addImm(NumBytes);
+ .addReg(NewReg).addImm(NewImm);
+
+ // FIXME: change this when mips goes MC".
+ if (ATUsed)
+ BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
}
}
+
+void MipsFrameLowering::
+processFunctionBeforeFrameFinalized(MachineFunction &MF) const {
+ const MipsRegisterInfo *RegInfo =
+ static_cast<const MipsRegisterInfo*>(MF.getTarget().getRegisterInfo());
+ RegInfo->processFunctionBeforeFrameFinalized(MF);
+}
projects / oota-llvm.git / blobdiff