//===- X86RegisterInfo.cpp - X86 Register Information -----------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
//
// This file contains the X86 implementation of the MRegisterInfo class. This
// file is responsible for the frame pointer elimination optimization on X86.
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "Support/CommandLine.h"
+#include "Support/STLExtras.h"
+using namespace llvm;
namespace {
cl::opt<bool>
}
}
-void X86RegisterInfo::storeRegToStackSlot(MachineBasicBlock &MBB,
- MachineBasicBlock::iterator &MBBI,
- unsigned SrcReg, int FrameIdx,
- const TargetRegisterClass *RC) const {
+int X86RegisterInfo::storeRegToStackSlot(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MI,
+ unsigned SrcReg, int FrameIdx,
+ const TargetRegisterClass *RC) const {
static const unsigned Opcode[] =
{ X86::MOVrm8, X86::MOVrm16, X86::MOVrm32, X86::FSTPr80 };
- MachineInstr *MI = addFrameReference(BuildMI(Opcode[getIdx(RC)], 5),
+ MachineInstr *I = addFrameReference(BuildMI(Opcode[getIdx(RC)], 5),
FrameIdx).addReg(SrcReg);
- MBBI = MBB.insert(MBBI, MI)+1;
+ MBB.insert(MI, I);
+ return 1;
}
-void X86RegisterInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
- MachineBasicBlock::iterator &MBBI,
- unsigned DestReg, int FrameIdx,
- const TargetRegisterClass *RC) const{
+int X86RegisterInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MI,
+ unsigned DestReg, int FrameIdx,
+ const TargetRegisterClass *RC) const{
static const unsigned Opcode[] =
{ X86::MOVmr8, X86::MOVmr16, X86::MOVmr32, X86::FLDr80 };
- MachineInstr *MI = addFrameReference(BuildMI(Opcode[getIdx(RC)], 4, DestReg),
- FrameIdx);
- MBBI = MBB.insert(MBBI, MI)+1;
+ unsigned OC = Opcode[getIdx(RC)];
+ MBB.insert(MI, addFrameReference(BuildMI(OC, 4, DestReg), FrameIdx));
+ return 1;
}
-void X86RegisterInfo::copyRegToReg(MachineBasicBlock &MBB,
- MachineBasicBlock::iterator &MBBI,
- unsigned DestReg, unsigned SrcReg,
- const TargetRegisterClass *RC) const {
+int X86RegisterInfo::copyRegToReg(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MI,
+ unsigned DestReg, unsigned SrcReg,
+ const TargetRegisterClass *RC) const {
static const unsigned Opcode[] =
{ X86::MOVrr8, X86::MOVrr16, X86::MOVrr32, X86::FpMOV };
- MachineInstr *MI = BuildMI(Opcode[getIdx(RC)],1,DestReg).addReg(SrcReg);
- MBBI = MBB.insert(MBBI, MI)+1;
+ MBB.insert(MI, BuildMI(Opcode[getIdx(RC)],1,DestReg).addReg(SrcReg));
+ return 1;
}
//===----------------------------------------------------------------------===//
return NoFPElim || MF.getFrameInfo()->hasVarSizedObjects();
}
-// hasSPAdjust - Return true if this function has ESP adjustment instructions in
-// the prolog and epilog which allocate local stack space. This is neccesary
-// because we elide these instructions if there are no function calls in the
-// current function (ie, this is a leaf function). In this case, we can refer
-// beyond the stack pointer because we know that nothing will trample on that
-// part of the stack.
-//
-static bool hasSPAdjust(MachineFunction &MF) {
- assert(!hasFP(MF) && "Can only eliminate SP adjustment if no frame-pointer!");
- return MF.getFrameInfo()->hasCalls();
-}
-
-void X86RegisterInfo::eliminateCallFramePseudoInstr(MachineFunction &MF,
- MachineBasicBlock &MBB,
- MachineBasicBlock::iterator &I) const {
- MachineInstr *New = 0, *Old = *I;;
+void X86RegisterInfo::
+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 ESP, <amt>' and the adjcallstackdown instruction into 'add ESP,
// <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
unsigned Align = MF.getTarget().getFrameInfo().getStackAlignment();
Amount = (Amount+Align-1)/Align*Align;
+ MachineInstr *New;
if (Old->getOpcode() == X86::ADJCALLSTACKDOWN) {
- New=BuildMI(X86::SUBri32, 2, X86::ESP).addReg(X86::ESP).addZImm(Amount);
+ New=BuildMI(X86::SUBri32, 1, X86::ESP, MOTy::UseAndDef).addZImm(Amount);
} else {
assert(Old->getOpcode() == X86::ADJCALLSTACKUP);
- New=BuildMI(X86::ADDri32, 2, X86::ESP).addReg(X86::ESP).addZImm(Amount);
+ New=BuildMI(X86::ADDri32, 1, X86::ESP, MOTy::UseAndDef).addZImm(Amount);
}
+
+ // Replace the pseudo instruction with a new instruction...
+ MBB.insert(I, New);
}
}
- if (New)
- *I = New; // Replace the pseudo instruction with a new instruction...
- else
- I = MBB.erase(I);// Just delete the pseudo instruction...
- delete Old;
+ MBB.erase(I);
}
void X86RegisterInfo::eliminateFrameIndex(MachineFunction &MF,
- MachineBasicBlock::iterator &II) const {
+ MachineBasicBlock::iterator II) const {
unsigned i = 0;
- MachineInstr &MI = **II;
+ MachineInstr &MI = *II;
while (!MI.getOperand(i).isFrameIndex()) {
++i;
assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex) +
MI.getOperand(i+3).getImmedValue()+4;
- if (!hasFP(MF) && hasSPAdjust(MF)) {
- const MachineFrameInfo *MFI = MF.getFrameInfo();
- Offset += MFI->getStackSize();
- }
+ if (!hasFP(MF))
+ Offset += MF.getFrameInfo()->getStackSize();
+ else
+ Offset += 4; // Skip the saved EBP
MI.SetMachineOperandConst(i+3, MachineOperand::MO_SignExtendedImmed, Offset);
}
-void X86RegisterInfo::processFunctionBeforeFrameFinalized(MachineFunction &MF)
- const {
+void
+X86RegisterInfo::processFunctionBeforeFrameFinalized(MachineFunction &MF) const{
if (hasFP(MF)) {
// Create a frame entry for the EBP register that must be saved.
- int FrameIdx = MF.getFrameInfo()->CreateStackObject(4, 4);
- assert(FrameIdx == MF.getFrameInfo()->getObjectIndexEnd()-1 &&
- "Slot for EBP register must be last in order to be found!");
+ int FrameIdx = MF.getFrameInfo()->CreateFixedObject(4, -8);
+ assert(FrameIdx == MF.getFrameInfo()->getObjectIndexBegin() &&
+ "Slot for EBP register must be last in order to be found!");
}
}
if (hasFP(MF)) {
// Get the offset of the stack slot for the EBP register... which is
// guaranteed to be the last slot by processFunctionBeforeFrameFinalized.
- int EBPOffset = MFI->getObjectOffset(MFI->getObjectIndexEnd()-1)+4;
+ int EBPOffset = MFI->getObjectOffset(MFI->getObjectIndexBegin())+4;
+ if (NumBytes) { // adjust stack pointer: ESP -= numbytes
+ MI= BuildMI(X86::SUBri32, 1, X86::ESP, MOTy::UseAndDef).addZImm(NumBytes);
+ MBB.insert(MBBI, MI);
+ }
+
+ // Save EBP into the appropriate stack slot...
MI = addRegOffset(BuildMI(X86::MOVrm32, 5), // mov [ESP-<offset>], EBP
- X86::ESP, EBPOffset).addReg(X86::EBP);
- MBBI = MBB.insert(MBBI, MI)+1;
-
- MI = BuildMI(X86::MOVrr32, 2, X86::EBP).addReg(X86::ESP);
- MBBI = MBB.insert(MBBI, MI)+1;
+ X86::ESP, EBPOffset+NumBytes).addReg(X86::EBP);
+ MBB.insert(MBBI, MI);
+
+ // Update EBP with the new base value...
+ if (NumBytes == 4) // mov EBP, ESP
+ MI = BuildMI(X86::MOVrr32, 2, X86::EBP).addReg(X86::ESP);
+ else // lea EBP, [ESP+StackSize]
+ MI = addRegOffset(BuildMI(X86::LEAr32, 5, X86::EBP), X86::ESP,NumBytes-4);
+
+ MBB.insert(MBBI, MI);
+
} else {
- // If we don't have a frame pointer, and the function contains no call sites
- // (it's a leaf function), we don't have to emit ANY stack adjustment
- // instructions at all, we can just refer to the area beyond the stack
- // pointer. This can be important for small functions.
- //
- if (!hasSPAdjust(MF)) return;
-
- // When we have no frame pointer, we reserve argument space for call sites
- // in the function immediately on entry to the current function. This
- // eliminates the need for add/sub ESP brackets around call sites.
- //
- NumBytes += MFI->getMaxCallFrameSize();
-
- // Round the size to a multiple of the alignment (don't forget the 4 byte
- // offset though).
- unsigned Align = MF.getTarget().getFrameInfo().getStackAlignment();
- NumBytes = ((NumBytes+4)+Align-1)/Align*Align - 4;
+ if (MFI->hasCalls()) {
+ // When we have no frame pointer, we reserve argument space for call sites
+ // in the function immediately on entry to the current function. This
+ // eliminates the need for add/sub ESP brackets around call sites.
+ //
+ NumBytes += MFI->getMaxCallFrameSize();
+
+ // Round the size to a multiple of the alignment (don't forget the 4 byte
+ // offset though).
+ unsigned Align = MF.getTarget().getFrameInfo().getStackAlignment();
+ NumBytes = ((NumBytes+4)+Align-1)/Align*Align - 4;
+ }
// Update frame info to pretend that this is part of the stack...
MFI->setStackSize(NumBytes);
- }
- if (NumBytes) {
- // adjust stack pointer: ESP -= numbytes
- MI = BuildMI(X86::SUBri32, 2, X86::ESP).addReg(X86::ESP).addZImm(NumBytes);
- MBBI = 1+MBB.insert(MBBI, MI);
+ if (NumBytes) {
+ // adjust stack pointer: ESP -= numbytes
+ MI= BuildMI(X86::SUBri32, 1, X86::ESP, MOTy::UseAndDef).addZImm(NumBytes);
+ MBB.insert(MBBI, MI);
+ }
}
}
void X86RegisterInfo::emitEpilogue(MachineFunction &MF,
- MachineBasicBlock &MBB) const {
+ MachineBasicBlock &MBB) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
- MachineBasicBlock::iterator MBBI = MBB.end()-1;
+ MachineBasicBlock::iterator MBBI = prior(MBB.end());
MachineInstr *MI;
- assert((*MBBI)->getOpcode() == X86::RET &&
+ assert(MBBI->getOpcode() == X86::RET &&
"Can only insert epilog into returning blocks");
if (hasFP(MF)) {
// mov ESP, EBP
MI = BuildMI(X86::MOVrr32, 1,X86::ESP).addReg(X86::EBP);
- MBBI = 1+MBB.insert(MBBI, MI);
+ MBB.insert(MBBI, MI);
- // mov EBP, [ESP-<offset>]
- MI = addRegOffset(BuildMI(X86::MOVmr32, 5, X86::EBP), X86::ESP, EBPOffset);
- MBBI = 1+MBB.insert(MBBI, MI);
+ // pop EBP
+ MI = BuildMI(X86::POPr32, 0, X86::EBP);
+ MBB.insert(MBBI, MI);
} else {
- if (!hasSPAdjust(MF)) return;
-
// Get the number of bytes allocated from the FrameInfo...
unsigned NumBytes = MFI->getStackSize();
if (NumBytes) { // adjust stack pointer back: ESP += numbytes
- MI =BuildMI(X86::ADDri32, 2, X86::ESP).addReg(X86::ESP).addZImm(NumBytes);
- MBBI = 1+MBB.insert(MBBI, MI);
+ MI =BuildMI(X86::ADDri32, 1, X86::ESP, MOTy::UseAndDef).addZImm(NumBytes);
+ MBB.insert(MBBI, MI);
}
}
}
default: assert(0 && "Invalid type to getClass!");
case Type::BoolTyID:
case Type::SByteTyID:
- case Type::UByteTyID: return &r8Instance;
+ case Type::UByteTyID: return &R8Instance;
case Type::ShortTyID:
- case Type::UShortTyID: return &r16Instance;
+ case Type::UShortTyID: return &R16Instance;
case Type::IntTyID:
case Type::UIntTyID:
- case Type::PointerTyID: return &r32Instance;
+ case Type::PointerTyID: return &R32Instance;
case Type::FloatTyID:
- case Type::DoubleTyID: return &rFPInstance;
+ case Type::DoubleTyID: return &RFPInstance;
}
}
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