-//===- AlphaRegisterInfo.cpp - Alpha Register Information ---*- C++ -*-----===//
+//===- AlphaRegisterInfo.cpp - Alpha Register Information -------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
#include <iostream>
using namespace llvm;
+//These describe LDAx
+static const int IMM_LOW = -32768;
+static const int IMM_HIGH = 32767;
+static const int IMM_MULT = 65536;
+
+static long getUpper16(long l)
+{
+ long y = l / IMM_MULT;
+ if (l % IMM_MULT > IMM_HIGH)
+ ++y;
+ return y;
+}
+
+static long getLower16(long l)
+{
+ long h = getUpper16(l);
+ return l - h * IMM_MULT;
+}
AlphaRegisterInfo::AlphaRegisterInfo()
: AlphaGenRegisterInfo(Alpha::ADJUSTSTACKDOWN, Alpha::ADJUSTSTACKUP)
eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
if (hasFP(MF)) {
- assert(0 && "TODO");
// If we have a frame pointer, turn the adjcallstackup instruction into a
// 'sub ESP, <amt>' and the adjcallstackdown instruction into 'add ESP,
// <amt>'
unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
Amount = (Amount+Align-1)/Align*Align;
-// MachineInstr *New;
-// if (Old->getOpcode() == X86::ADJCALLSTACKDOWN) {
-// New=BuildMI(X86::SUB32ri, 1, X86::ESP, MachineOperand::UseAndDef)
-// .addZImm(Amount);
-// } else {
-// assert(Old->getOpcode() == X86::ADJCALLSTACKUP);
-// New=BuildMI(X86::ADD32ri, 1, X86::ESP, MachineOperand::UseAndDef)
-// .addZImm(Amount);
-// }
-
+ MachineInstr *New;
+ if (Old->getOpcode() == Alpha::ADJUSTSTACKDOWN) {
+ New=BuildMI(Alpha::LDA, 2, Alpha::R30)
+ .addImm(-Amount).addReg(Alpha::R30);
+ } else {
+ assert(Old->getOpcode() == Alpha::ADJUSTSTACKUP);
+ New=BuildMI(Alpha::LDA, 2, Alpha::R30)
+ .addImm(Amount).addReg(Alpha::R30);
+ }
+
// Replace the pseudo instruction with a new instruction...
- //MBB.insert(I, New);
- abort();
+ MBB.insert(I, New);
}
}
MBB.erase(I);
}
+//Alpha has a slightly funny stack:
+//Args
+//<- incoming SP
+//fixed locals (and spills, callee saved, etc)
+//<- FP
+//variable locals
+//<- SP
+
void
AlphaRegisterInfo::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();
// Add the base register of R30 (SP) or R15 (FP).
- MI.SetMachineOperandReg(i + 1, hasFP(MF) ? Alpha::R15 : Alpha::R30);
+ MI.SetMachineOperandReg(i + 1, FP ? Alpha::R15 : Alpha::R30);
- // Now add the frame object offset to the offset from r1.
+ // Now add the frame object offset to the offset from the virtual frame index.
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.
+ DEBUG(std::cerr << "FI: " << FrameIndex << " Offset: " << Offset << "\n");
+
Offset += MF.getFrameInfo()->getStackSize();
+
+ DEBUG(std::cerr << "Corrected Offset " << Offset <<
+ " for stack size: " << MF.getFrameInfo()->getStackSize() << "\n");
- if (Offset > 32767 || Offset < -32768) {
- std::cerr << "Offset needs to be " << Offset << "\n";
- assert(0 && "stack too big");
- } else {
- MI.SetMachineOperandConst(i, MachineOperand::MO_SignExtendedImmed, Offset);
- }
+ if (Offset > IMM_HIGH || Offset < IMM_LOW) {
+ //so in this case, we need to use a temporary register, and move the original
+ //inst off the SP/FP
+ //fix up the old:
+ MI.SetMachineOperandReg(i + 1, Alpha::R28);
+ MI.SetMachineOperandConst(i, MachineOperand::MO_SignExtendedImmed,
+ getLower16(Offset));
+ //insert the new
+ MachineInstr* nMI=BuildMI(Alpha::LDAH, 2, Alpha::R28)
+ .addImm(getUpper16(Offset)).addReg(FP ? Alpha::R15 : Alpha::R30);
+ MBB.insert(II, nMI);
+ } else {
+ MI.SetMachineOperandConst(i, MachineOperand::MO_SignExtendedImmed, Offset);
+ }
}
MachineBasicBlock::iterator MBBI = MBB.begin();
MachineFrameInfo *MFI = MF.getFrameInfo();
MachineInstr *MI;
+ bool FP = hasFP(MF);
//handle GOP offset
MI = BuildMI(Alpha::LDGP, 0);
MBB.insert(MBBI, MI);
// Get the number of bytes to allocate from the FrameInfo
- unsigned NumBytes = MFI->getStackSize();
+ long NumBytes = MFI->getStackSize();
- if (MFI->hasCalls()) {
+ 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.
+ //If there is a frame pointer, then we don't do this
NumBytes += MFI->getMaxCallFrameSize();
- std::cerr << "Added " << MFI->getMaxCallFrameSize() << " to the stack due to calls\n";
+ DEBUG(std::cerr << "Added " << MFI->getMaxCallFrameSize()
+ << " to the stack due to calls\n");
}
+ if (FP)
+ NumBytes += 8; //reserve space for the old FP
+
// Do we need to allocate space on the stack?
if (NumBytes == 0) return;
- // Add the size of R30 to NumBytes size for the store of R30 to the
- // stack
-// std::cerr << "Spillsize of R30 is " << getSpillSize(Alpha::R30) << "\n";
-// NumBytes = NumBytes + getSpillSize(Alpha::R30)/8;
-
// Update frame info to pretend that this is part of the stack...
MFI->setStackSize(NumBytes);
-
+
// adjust stack pointer: r30 -= numbytes
-
- if (NumBytes <= 32767) {
- MI=BuildMI(Alpha::LDA, 2, Alpha::R30).addImm(-NumBytes).addReg(Alpha::R30);
+ NumBytes = -NumBytes;
+ if (NumBytes >= IMM_LOW) {
+ MI=BuildMI(Alpha::LDA, 2, Alpha::R30).addImm(NumBytes).addReg(Alpha::R30);
MBB.insert(MBBI, MI);
- } else if ((unsigned long)NumBytes <= (unsigned long)32767 * (unsigned long)65536) {
- long y = NumBytes / 65536;
- if (NumBytes % 65536 > 32767)
- ++y;
- MI=BuildMI(Alpha::LDAH, 2, Alpha::R30).addImm(-y).addReg(Alpha::R30);
+ } else if (getUpper16(NumBytes) >= IMM_LOW) {
+ MI=BuildMI(Alpha::LDAH, 2, Alpha::R30).addImm(getUpper16(NumBytes)).addReg(Alpha::R30);
MBB.insert(MBBI, MI);
- MI=BuildMI(Alpha::LDA, 2, Alpha::R30).addImm(-(NumBytes - y * 65536)).addReg(Alpha::R30);
+ MI=BuildMI(Alpha::LDA, 2, Alpha::R30).addImm(getLower16(NumBytes)).addReg(Alpha::R30);
MBB.insert(MBBI, MI);
} else {
std::cerr << "Too big a stack frame at " << NumBytes << "\n";
abort();
}
+
+ //now if we need to, save the old FP and set the new
+ if (FP)
+ {
+ MI=BuildMI(Alpha::STQ, 3).addReg(Alpha::R15).addImm(0).addReg(Alpha::R30);
+ MBB.insert(MBBI, MI);
+ //this must be the last instr in the prolog
+ MI=BuildMI(Alpha::BIS, 2, Alpha::R15).addReg(Alpha::R30).addReg(Alpha::R30);
+ MBB.insert(MBBI, MI);
+ }
+
}
void AlphaRegisterInfo::emitEpilogue(MachineFunction &MF,
assert((MBBI->getOpcode() == Alpha::RET || MBBI->getOpcode() == Alpha::RETURN) &&
"Can only insert epilog into returning blocks");
+ bool FP = hasFP(MF);
+
// Get the number of bytes allocated from the FrameInfo...
- unsigned NumBytes = MFI->getStackSize();
+ long NumBytes = MFI->getStackSize();
+
+ //now if we need to, restore the old FP
+ if (FP)
+ {
+ //copy the FP into the SP (discards allocas)
+ MI=BuildMI(Alpha::BIS, 2, Alpha::R30).addReg(Alpha::R15).addReg(Alpha::R15);
+ MBB.insert(MBBI, MI);
+ //restore the FP
+ MI=BuildMI(Alpha::LDQ, 2, Alpha::R15).addImm(0).addReg(Alpha::R15);
+ MBB.insert(MBBI, MI);
+ }
if (NumBytes != 0)
{
- if (NumBytes <= 32767) {
+ if (NumBytes <= IMM_HIGH) {
MI=BuildMI(Alpha::LDA, 2, Alpha::R30).addImm(NumBytes).addReg(Alpha::R30);
MBB.insert(MBBI, MI);
- } else if ((unsigned long)NumBytes <= (unsigned long)32767 * (unsigned long)65536) {
- long y = NumBytes / 65536;
- if (NumBytes % 65536 > 32767)
- ++y;
- MI=BuildMI(Alpha::LDAH, 2, Alpha::R30).addImm(y).addReg(Alpha::R30);
+ } else if (getUpper16(NumBytes) <= IMM_HIGH) {
+ MI=BuildMI(Alpha::LDAH, 2, Alpha::R30).addImm(getUpper16(NumBytes)).addReg(Alpha::R30);
MBB.insert(MBBI, MI);
- MI=BuildMI(Alpha::LDA, 2, Alpha::R30).addImm(NumBytes - y * 65536).addReg(Alpha::R30);
+ MI=BuildMI(Alpha::LDA, 2, Alpha::R30).addImm(getLower16(NumBytes)).addReg(Alpha::R30);
MBB.insert(MBBI, MI);
} else {
std::cerr << "Too big a stack frame at " << NumBytes << "\n";
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