llvm-6502/lib/Target/IA64/IA64RegisterInfo.cpp
2009-02-23 00:42:30 +00:00

320 lines
12 KiB
C++

//===- IA64RegisterInfo.cpp - IA64 Register 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 IA64 implementation of the TargetRegisterInfo 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/CodeGen/MachineLocation.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/STLExtras.h"
using namespace llvm;
IA64RegisterInfo::IA64RegisterInfo(const TargetInstrInfo &tii)
: IA64GenRegisterInfo(IA64::ADJUSTCALLSTACKDOWN, IA64::ADJUSTCALLSTACKUP),
TII(tii) {}
const unsigned* IA64RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF)
const {
static const unsigned CalleeSavedRegs[] = {
IA64::r5, 0
};
return CalleeSavedRegs;
}
const TargetRegisterClass* const*
IA64RegisterInfo::getCalleeSavedRegClasses(const MachineFunction *MF) const {
static const TargetRegisterClass * const CalleeSavedRegClasses[] = {
&IA64::GRRegClass, 0
};
return CalleeSavedRegClasses;
}
BitVector IA64RegisterInfo::getReservedRegs(const MachineFunction &MF) const {
BitVector Reserved(getNumRegs());
Reserved.set(IA64::r0);
Reserved.set(IA64::r1);
Reserved.set(IA64::r2);
Reserved.set(IA64::r5);
Reserved.set(IA64::r12);
Reserved.set(IA64::r13);
Reserved.set(IA64::r22);
Reserved.set(IA64::rp);
return Reserved;
}
//===----------------------------------------------------------------------===//
// 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.
//
bool IA64RegisterInfo::hasFP(const MachineFunction &MF) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
return NoFramePointerElim || MFI->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).getImm();
DebugLoc dl = Old->getDebugLoc();
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;
// Replace the pseudo instruction with a new instruction...
if (Old->getOpcode() == IA64::ADJUSTCALLSTACKDOWN) {
BuildMI(MBB, I, dl, TII.get(IA64::ADDIMM22), IA64::r12)
.addReg(IA64::r12).addImm(-Amount);
} else {
assert(Old->getOpcode() == IA64::ADJUSTCALLSTACKUP);
BuildMI(MBB, I, dl, TII.get(IA64::ADDIMM22), IA64::r12)
.addReg(IA64::r12).addImm(Amount);
}
}
}
MBB.erase(I);
}
void IA64RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
int SPAdj, RegScavenger *RS)const{
assert(SPAdj == 0 && "Unexpected");
unsigned i = 0;
MachineInstr &MI = *II;
MachineBasicBlock &MBB = *MI.getParent();
MachineFunction &MF = *MBB.getParent();
DebugLoc dl = MI.getDebugLoc();
bool FP = hasFP(MF);
while (!MI.getOperand(i).isFI()) {
++i;
assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
}
int FrameIndex = MI.getOperand(i).getIndex();
// choose a base register: ( hasFP? framepointer : stack pointer )
unsigned BaseRegister = FP ? IA64::r5 : IA64::r12;
// Add the base register
MI.getOperand(i).ChangeToRegister(BaseRegister, false);
// 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.getOperand(i).ChangeToRegister(IA64::r22, false);
//insert the new
BuildMI(MBB, II, dl, TII.get(IA64::ADDIMM22), IA64::r22)
.addReg(BaseRegister).addImm(Offset);
} else { // it's big
//fix up the old:
MI.getOperand(i).ChangeToRegister(IA64::r22, false);
BuildMI(MBB, II, dl, TII.get(IA64::MOVLIMM64), IA64::r22).addImm(Offset);
BuildMI(MBB, II, dl, TII.get(IA64::ADD), IA64::r22).addReg(BaseRegister)
.addReg(IA64::r22);
}
}
void IA64RegisterInfo::emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB
MachineBasicBlock::iterator MBBI = MBB.begin();
MachineFrameInfo *MFI = MF.getFrameInfo();
bool FP = hasFP(MF);
DebugLoc dl = (MBBI != MBB.end() ?
MBBI->getDebugLoc() : DebugLoc::getUnknownLoc());
// 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.getRegInfo().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;
}
}
if (MBBI != MBB.end()) dl = MBBI->getDebugLoc();
BuildMI(MBB, MBBI, dl, TII.get(IA64::ALLOC)).
addReg(dstRegOfPseudoAlloc).addImm(0).
addImm(numStackedGPRsUsed).addImm(numOutRegsUsed).addImm(0);
// Get the number of bytes to allocate from the FrameInfo
unsigned NumBytes = MFI->getStackSize();
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) {
BuildMI(MBB, MBBI, dl, TII.get(IA64::ADDIMM22),IA64::r12).addReg(IA64::r12).
addImm(-NumBytes);
} else { // we use r22 as a scratch register here
// first load the decrement into r22
BuildMI(MBB, MBBI, dl, TII.get(IA64::MOVLIMM64), IA64::r22).
addImm(-NumBytes);
// FIXME: MOVLSI32 expects a _u_32imm
// then add (subtract) it to r12 (stack ptr)
BuildMI(MBB, MBBI, dl, TII.get(IA64::ADD), IA64::r12)
.addReg(IA64::r12).addReg(IA64::r22);
}
// now if we need to, save the old FP and set the new
if (FP) {
BuildMI(MBB, MBBI,dl,TII.get(IA64::ST8)).addReg(IA64::r12).addReg(IA64::r5);
// this must be the last instr in the prolog ? (XXX: why??)
BuildMI(MBB, MBBI, dl, TII.get(IA64::MOV), IA64::r5).addReg(IA64::r12);
}
}
void IA64RegisterInfo::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
MachineBasicBlock::iterator MBBI = prior(MBB.end());
assert(MBBI->getOpcode() == IA64::RET &&
"Can only insert epilog into returning blocks");
DebugLoc dl = MBBI->getDebugLoc();
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)
BuildMI(MBB, MBBI, dl, TII.get(IA64::MOV), IA64::r12).addReg(IA64::r5);
//restore the FP
BuildMI(MBB, MBBI, dl, TII.get(IA64::LD8), IA64::r5).addReg(IA64::r5);
}
if (NumBytes != 0) {
if (NumBytes <= 8191) {
BuildMI(MBB, MBBI, dl, TII.get(IA64::ADDIMM22),IA64::r12).
addReg(IA64::r12).addImm(NumBytes);
} else {
BuildMI(MBB, MBBI, dl, TII.get(IA64::MOVLIMM64), IA64::r22).
addImm(NumBytes);
BuildMI(MBB, MBBI, dl, TII.get(IA64::ADD), IA64::r12).addReg(IA64::r12).
addReg(IA64::r22);
}
}
}
unsigned IA64RegisterInfo::getRARegister() const {
assert(0 && "What is the return address register");
return 0;
}
unsigned IA64RegisterInfo::getFrameRegister(MachineFunction &MF) const {
return hasFP(MF) ? IA64::r5 : IA64::r12;
}
unsigned IA64RegisterInfo::getEHExceptionRegister() const {
assert(0 && "What is the exception register");
return 0;
}
unsigned IA64RegisterInfo::getEHHandlerRegister() const {
assert(0 && "What is the exception handler register");
return 0;
}
int IA64RegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
assert(0 && "What is the dwarf register number");
return -1;
}
#include "IA64GenRegisterInfo.inc"