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llvm-mirror/lib/Target/IA64/IA64RegisterInfo.cpp
Duraid Madina 13335846a8 some hoovering 
llvm-svn: 25643
2006-01-26 09:08:31 +00:00

333 lines
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//===- IA64RegisterInfo.cpp - IA64 Register Information ---------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Duraid Madina and is distributed under the
// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the IA64 implementation of the MRegisterInfo class. This
// file is responsible for the frame pointer elimination optimization on IA64.
//
//===----------------------------------------------------------------------===//
#include "IA64.h"
#include "IA64RegisterInfo.h"
#include "IA64InstrBuilder.h"
#include "IA64MachineFunctionInfo.h"
#include "llvm/Constants.h"
#include "llvm/Type.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/ADT/STLExtras.h"
#include <iostream>
using namespace llvm;
IA64RegisterInfo::IA64RegisterInfo()
: IA64GenRegisterInfo(IA64::ADJUSTCALLSTACKDOWN, IA64::ADJUSTCALLSTACKUP) {}
void IA64RegisterInfo::storeRegToStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
unsigned SrcReg, int FrameIdx,
const TargetRegisterClass *RC) const{
if (RC == IA64::FPRegisterClass) {
BuildMI(MBB, MI, IA64::STF_SPILL, 2).addFrameIndex(FrameIdx).addReg(SrcReg);
} else if (RC == IA64::GRRegisterClass) {
BuildMI(MBB, MI, IA64::ST8, 2).addFrameIndex(FrameIdx).addReg(SrcReg);
}
else if (RC == IA64::PRRegisterClass) {
/* we use IA64::r2 as a temporary register for doing this hackery. */
// first we load 0:
BuildMI(MBB, MI, IA64::MOV, 1, IA64::r2).addReg(IA64::r0);
// then conditionally add 1:
BuildMI(MBB, MI, IA64::CADDIMM22, 3, IA64::r2).addReg(IA64::r2)
.addImm(1).addReg(SrcReg);
// and then store it to the stack
BuildMI(MBB, MI, IA64::ST8, 2).addFrameIndex(FrameIdx).addReg(IA64::r2);
} else assert(0 &&
"sorry, I don't know how to store this sort of reg in the stack\n");
}
void IA64RegisterInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
unsigned DestReg, int FrameIdx,
const TargetRegisterClass *RC)const{
if (RC == IA64::FPRegisterClass) {
BuildMI(MBB, MI, IA64::LDF_FILL, 1, DestReg).addFrameIndex(FrameIdx);
} else if (RC == IA64::GRRegisterClass) {
BuildMI(MBB, MI, IA64::LD8, 1, DestReg).addFrameIndex(FrameIdx);
} else if (RC == IA64::PRRegisterClass) {
// first we load a byte from the stack into r2, our 'predicate hackery'
// scratch reg
BuildMI(MBB, MI, IA64::LD8, 1, IA64::r2).addFrameIndex(FrameIdx);
// then we compare it to zero. If it _is_ zero, compare-not-equal to
// r0 gives us 0, which is what we want, so that's nice.
BuildMI(MBB, MI, IA64::CMPNE, 2, DestReg).addReg(IA64::r2).addReg(IA64::r0);
} else assert(0 &&
"sorry, I don't know how to load this sort of reg from the stack\n");
}
void IA64RegisterInfo::copyRegToReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
unsigned DestReg, unsigned SrcReg,
const TargetRegisterClass *RC) const {
if(RC == IA64::PRRegisterClass ) // if a bool, we use pseudocode
// (SrcReg) DestReg = cmp.eq.unc(r0, r0)
BuildMI(MBB, MI, IA64::PCMPEQUNC, 3, DestReg).addReg(IA64::r0).addReg(IA64::r0).addReg(SrcReg);
else // otherwise, MOV works (for both gen. regs and FP regs)
BuildMI(MBB, MI, IA64::MOV, 1, DestReg).addReg(SrcReg);
}
//===----------------------------------------------------------------------===//
// Stack Frame Processing methods
//===----------------------------------------------------------------------===//
// 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.
//
static bool hasFP(MachineFunction &MF) {
return NoFramePointerElim || MF.getFrameInfo()->hasVarSizedObjects();
}
void IA64RegisterInfo::
eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
if (hasFP(MF)) {
// If we have a frame pointer, turn the adjcallstackup instruction into a
// 'sub SP, <amt>' and the adjcallstackdown instruction into 'add SP,
// <amt>'
MachineInstr *Old = I;
unsigned Amount = Old->getOperand(0).getImmedValue();
if (Amount != 0) {
// We need to keep the stack aligned properly. To do this, we round the
// amount of space needed for the outgoing arguments up to the next
// alignment boundary.
unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
Amount = (Amount+Align-1)/Align*Align;
MachineInstr *New;
if (Old->getOpcode() == IA64::ADJUSTCALLSTACKDOWN) {
New=BuildMI(IA64::ADDIMM22, 2, IA64::r12).addReg(IA64::r12)
.addSImm(-Amount);
} else {
assert(Old->getOpcode() == IA64::ADJUSTCALLSTACKUP);
New=BuildMI(IA64::ADDIMM22, 2, IA64::r12).addReg(IA64::r12)
.addSImm(Amount);
}
// Replace the pseudo instruction with a new instruction...
MBB.insert(I, New);
}
}
MBB.erase(I);
}
void IA64RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II) const{
unsigned i = 0;
MachineInstr &MI = *II;
MachineBasicBlock &MBB = *MI.getParent();
MachineFunction &MF = *MBB.getParent();
bool FP = hasFP(MF);
while (!MI.getOperand(i).isFrameIndex()) {
++i;
assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
}
int FrameIndex = MI.getOperand(i).getFrameIndex();
// choose a base register: ( hasFP? framepointer : stack pointer )
unsigned BaseRegister = FP ? IA64::r5 : IA64::r12;
// Add the base register
MI.SetMachineOperandReg(i, BaseRegister);
// Now add the frame object offset to the offset from r1.
int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex);
// If we're not using a Frame Pointer that has been set to the value of the
// SP before having the stack size subtracted from it, then add the stack size
// to Offset to get the correct offset.
Offset += MF.getFrameInfo()->getStackSize();
// XXX: we use 'r22' as another hack+slash temporary register here :(
if ( Offset <= 8191 && Offset >= -8192) { // smallish offset
//fix up the old:
MI.SetMachineOperandReg(i, IA64::r22);
MI.getOperand(i).setUse(); // mark r22 as being used
// (the bundler wants to know this)
//insert the new
MachineInstr* nMI=BuildMI(IA64::ADDIMM22, 2, IA64::r22)
.addReg(BaseRegister).addSImm(Offset);
MBB.insert(II, nMI);
} else { // it's big
//fix up the old:
MI.SetMachineOperandReg(i, IA64::r22);
MI.getOperand(i).setUse(); // mark r22 as being used
// (the bundler wants to know this)
MachineInstr* nMI;
nMI=BuildMI(IA64::MOVLIMM64, 1, IA64::r22).addSImm(Offset);
MBB.insert(II, nMI);
nMI=BuildMI(IA64::ADD, 2, IA64::r22).addReg(BaseRegister)
.addReg(IA64::r22);
MBB.insert(II, nMI);
}
}
void IA64RegisterInfo::emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB
MachineBasicBlock::iterator MBBI = MBB.begin();
MachineFrameInfo *MFI = MF.getFrameInfo();
MachineInstr *MI;
bool FP = hasFP(MF);
// first, we handle the 'alloc' instruction, that should be right up the
// top of any function
static const unsigned RegsInOrder[96] = { // there are 96 GPRs the
// RSE worries about
IA64::r32, IA64::r33, IA64::r34, IA64::r35,
IA64::r36, IA64::r37, IA64::r38, IA64::r39, IA64::r40, IA64::r41,
IA64::r42, IA64::r43, IA64::r44, IA64::r45, IA64::r46, IA64::r47,
IA64::r48, IA64::r49, IA64::r50, IA64::r51, IA64::r52, IA64::r53,
IA64::r54, IA64::r55, IA64::r56, IA64::r57, IA64::r58, IA64::r59,
IA64::r60, IA64::r61, IA64::r62, IA64::r63, IA64::r64, IA64::r65,
IA64::r66, IA64::r67, IA64::r68, IA64::r69, IA64::r70, IA64::r71,
IA64::r72, IA64::r73, IA64::r74, IA64::r75, IA64::r76, IA64::r77,
IA64::r78, IA64::r79, IA64::r80, IA64::r81, IA64::r82, IA64::r83,
IA64::r84, IA64::r85, IA64::r86, IA64::r87, IA64::r88, IA64::r89,
IA64::r90, IA64::r91, IA64::r92, IA64::r93, IA64::r94, IA64::r95,
IA64::r96, IA64::r97, IA64::r98, IA64::r99, IA64::r100, IA64::r101,
IA64::r102, IA64::r103, IA64::r104, IA64::r105, IA64::r106, IA64::r107,
IA64::r108, IA64::r109, IA64::r110, IA64::r111, IA64::r112, IA64::r113,
IA64::r114, IA64::r115, IA64::r116, IA64::r117, IA64::r118, IA64::r119,
IA64::r120, IA64::r121, IA64::r122, IA64::r123, IA64::r124, IA64::r125,
IA64::r126, IA64::r127 };
unsigned numStackedGPRsUsed=0;
for(int i=0; i<96; i++) {
if(MF.isPhysRegUsed(RegsInOrder[i]))
numStackedGPRsUsed=i+1; // (i+1 and not ++ - consider fn(fp, fp, int)
}
unsigned numOutRegsUsed=MF.getInfo<IA64FunctionInfo>()->outRegsUsed;
// XXX FIXME : this code should be a bit more reliable (in case there _isn't_ a pseudo_alloc in the MBB)
unsigned dstRegOfPseudoAlloc;
for(MBBI = MBB.begin(); /*MBBI->getOpcode() != IA64::PSEUDO_ALLOC*/; ++MBBI) {
assert(MBBI != MBB.end());
if(MBBI->getOpcode() == IA64::PSEUDO_ALLOC) {
dstRegOfPseudoAlloc=MBBI->getOperand(0).getReg();
break;
}
}
MI=BuildMI(IA64::ALLOC,5).addReg(dstRegOfPseudoAlloc).addImm(0).\
addImm(numStackedGPRsUsed).addImm(numOutRegsUsed).addImm(0);
MBB.insert(MBBI, MI);
// Get the number of bytes to allocate from the FrameInfo
unsigned NumBytes = MFI->getStackSize();
if (MFI->hasCalls() && !FP) {
// We reserve argument space for call sites in the function immediately on
// entry to the current function. This eliminates the need for add/sub
// brackets around call sites.
NumBytes += MFI->getMaxCallFrameSize();
}
if(FP)
NumBytes += 8; // reserve space for the old FP
// Do we need to allocate space on the stack?
if (NumBytes == 0)
return;
// Add 16 bytes at the bottom of the stack (scratch area)
// and round the size to a multiple of the alignment.
unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
unsigned Size = 16 + (FP ? 8 : 0);
NumBytes = (NumBytes+Size+Align-1)/Align*Align;
// Update frame info to pretend that this is part of the stack...
MFI->setStackSize(NumBytes);
// adjust stack pointer: r12 -= numbytes
if (NumBytes <= 8191) {
MI=BuildMI(IA64::ADDIMM22, 2, IA64::r12).addReg(IA64::r12).addImm(-NumBytes);
MBB.insert(MBBI, MI);
} else { // we use r22 as a scratch register here
MI=BuildMI(IA64::MOVLIMM64, 1, IA64::r22).addSImm(-NumBytes);
// FIXME: MOVLSI32 expects a _u_32imm
MBB.insert(MBBI, MI); // first load the decrement into r22
MI=BuildMI(IA64::ADD, 2, IA64::r12).addReg(IA64::r12).addReg(IA64::r22);
MBB.insert(MBBI, MI); // then add (subtract) it to r12 (stack ptr)
}
// now if we need to, save the old FP and set the new
if (FP) {
MI = BuildMI(IA64::ST8, 2).addReg(IA64::r12).addReg(IA64::r5);
MBB.insert(MBBI, MI);
// this must be the last instr in the prolog ? (XXX: why??)
MI = BuildMI(IA64::MOV, 1, IA64::r5).addReg(IA64::r12);
MBB.insert(MBBI, MI);
}
}
void IA64RegisterInfo::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
MachineBasicBlock::iterator MBBI = prior(MBB.end());
MachineInstr *MI;
assert(MBBI->getOpcode() == IA64::RET &&
"Can only insert epilog into returning blocks");
bool FP = hasFP(MF);
// Get the number of bytes allocated from the FrameInfo...
unsigned NumBytes = MFI->getStackSize();
//now if we need to, restore the old FP
if (FP)
{
//copy the FP into the SP (discards allocas)
MI=BuildMI(IA64::MOV, 1, IA64::r12).addReg(IA64::r5);
MBB.insert(MBBI, MI);
//restore the FP
MI=BuildMI(IA64::LD8, 1, IA64::r5).addReg(IA64::r5);
MBB.insert(MBBI, MI);
}
if (NumBytes != 0)
{
if (NumBytes <= 8191) {
MI=BuildMI(IA64::ADDIMM22, 2, IA64::r12).addReg(IA64::r12).addImm(NumBytes);
MBB.insert(MBBI, MI);
} else {
MI=BuildMI(IA64::MOVLIMM64, 1, IA64::r22).addImm(NumBytes);
MBB.insert(MBBI, MI);
MI=BuildMI(IA64::ADD, 2, IA64::r12).addReg(IA64::r12).addReg(IA64::r22);
MBB.insert(MBBI, MI);
}
}
}
#include "IA64GenRegisterInfo.inc"
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