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llvm-6502/lib/Target/X86/X86RegisterInfo.cpp
Duncan Sands 18f13c66bf Mark more constants unsigned, as warned about by icc (#68). 
Patch by Erick Tryzelaar.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81116 91177308-0d34-0410-b5e6-96231b3b80d8
2009-09-06 12:56:52 +00:00

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//===- X86RegisterInfo.cpp - X86 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 X86 implementation of the TargetRegisterInfo class.
// This file is responsible for the frame pointer elimination optimization
// on X86.
//
//===----------------------------------------------------------------------===//
#include "X86.h"
#include "X86RegisterInfo.h"
#include "X86InstrBuilder.h"
#include "X86MachineFunctionInfo.h"
#include "X86Subtarget.h"
#include "X86TargetMachine.h"
#include "llvm/Constants.h"
#include "llvm/Function.h"
#include "llvm/Type.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineLocation.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ErrorHandling.h"
using namespace llvm;
X86RegisterInfo::X86RegisterInfo(X86TargetMachine &tm,
const TargetInstrInfo &tii)
: X86GenRegisterInfo(tm.getSubtarget<X86Subtarget>().is64Bit() ?
X86::ADJCALLSTACKDOWN64 :
X86::ADJCALLSTACKDOWN32,
tm.getSubtarget<X86Subtarget>().is64Bit() ?
X86::ADJCALLSTACKUP64 :
X86::ADJCALLSTACKUP32),
TM(tm), TII(tii) {
// Cache some information.
const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
Is64Bit = Subtarget->is64Bit();
IsWin64 = Subtarget->isTargetWin64();
StackAlign = TM.getFrameInfo()->getStackAlignment();
if (Is64Bit) {
SlotSize = 8;
StackPtr = X86::RSP;
FramePtr = X86::RBP;
} else {
SlotSize = 4;
StackPtr = X86::ESP;
FramePtr = X86::EBP;
}
}
/// getDwarfRegNum - This function maps LLVM register identifiers to the DWARF
/// specific numbering, used in debug info and exception tables.
int X86RegisterInfo::getDwarfRegNum(unsigned RegNo, bool isEH) const {
const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
unsigned Flavour = DWARFFlavour::X86_64;
if (!Subtarget->is64Bit()) {
if (Subtarget->isTargetDarwin()) {
if (isEH)
Flavour = DWARFFlavour::X86_32_DarwinEH;
else
Flavour = DWARFFlavour::X86_32_Generic;
} else if (Subtarget->isTargetCygMing()) {
// Unsupported by now, just quick fallback
Flavour = DWARFFlavour::X86_32_Generic;
} else {
Flavour = DWARFFlavour::X86_32_Generic;
}
}
return X86GenRegisterInfo::getDwarfRegNumFull(RegNo, Flavour);
}
/// getX86RegNum - This function maps LLVM register identifiers to their X86
/// specific numbering, which is used in various places encoding instructions.
unsigned X86RegisterInfo::getX86RegNum(unsigned RegNo) {
switch(RegNo) {
case X86::RAX: case X86::EAX: case X86::AX: case X86::AL: return N86::EAX;
case X86::RCX: case X86::ECX: case X86::CX: case X86::CL: return N86::ECX;
case X86::RDX: case X86::EDX: case X86::DX: case X86::DL: return N86::EDX;
case X86::RBX: case X86::EBX: case X86::BX: case X86::BL: return N86::EBX;
case X86::RSP: case X86::ESP: case X86::SP: case X86::SPL: case X86::AH:
return N86::ESP;
case X86::RBP: case X86::EBP: case X86::BP: case X86::BPL: case X86::CH:
return N86::EBP;
case X86::RSI: case X86::ESI: case X86::SI: case X86::SIL: case X86::DH:
return N86::ESI;
case X86::RDI: case X86::EDI: case X86::DI: case X86::DIL: case X86::BH:
return N86::EDI;
case X86::R8: case X86::R8D: case X86::R8W: case X86::R8B:
return N86::EAX;
case X86::R9: case X86::R9D: case X86::R9W: case X86::R9B:
return N86::ECX;
case X86::R10: case X86::R10D: case X86::R10W: case X86::R10B:
return N86::EDX;
case X86::R11: case X86::R11D: case X86::R11W: case X86::R11B:
return N86::EBX;
case X86::R12: case X86::R12D: case X86::R12W: case X86::R12B:
return N86::ESP;
case X86::R13: case X86::R13D: case X86::R13W: case X86::R13B:
return N86::EBP;
case X86::R14: case X86::R14D: case X86::R14W: case X86::R14B:
return N86::ESI;
case X86::R15: case X86::R15D: case X86::R15W: case X86::R15B:
return N86::EDI;
case X86::ST0: case X86::ST1: case X86::ST2: case X86::ST3:
case X86::ST4: case X86::ST5: case X86::ST6: case X86::ST7:
return RegNo-X86::ST0;
case X86::XMM0: case X86::XMM8: case X86::MM0:
return 0;
case X86::XMM1: case X86::XMM9: case X86::MM1:
return 1;
case X86::XMM2: case X86::XMM10: case X86::MM2:
return 2;
case X86::XMM3: case X86::XMM11: case X86::MM3:
return 3;
case X86::XMM4: case X86::XMM12: case X86::MM4:
return 4;
case X86::XMM5: case X86::XMM13: case X86::MM5:
return 5;
case X86::XMM6: case X86::XMM14: case X86::MM6:
return 6;
case X86::XMM7: case X86::XMM15: case X86::MM7:
return 7;
default:
assert(isVirtualRegister(RegNo) && "Unknown physical register!");
llvm_unreachable("Register allocator hasn't allocated reg correctly yet!");
return 0;
}
}
const TargetRegisterClass *
X86RegisterInfo::getMatchingSuperRegClass(const TargetRegisterClass *A,
const TargetRegisterClass *B,
unsigned SubIdx) const {
switch (SubIdx) {
default: return 0;
case 1:
// 8-bit
if (B == &X86::GR8RegClass) {
if (A->getSize() == 2 || A->getSize() == 4 || A->getSize() == 8)
return A;
} else if (B == &X86::GR8_ABCD_LRegClass || B == &X86::GR8_ABCD_HRegClass) {
if (A == &X86::GR64RegClass || A == &X86::GR64_ABCDRegClass ||
A == &X86::GR64_NOREXRegClass ||
A == &X86::GR64_NOSPRegClass ||
A == &X86::GR64_NOREX_NOSPRegClass)
return &X86::GR64_ABCDRegClass;
else if (A == &X86::GR32RegClass || A == &X86::GR32_ABCDRegClass ||
A == &X86::GR32_NOREXRegClass ||
A == &X86::GR32_NOSPRegClass)
return &X86::GR32_ABCDRegClass;
else if (A == &X86::GR16RegClass || A == &X86::GR16_ABCDRegClass ||
A == &X86::GR16_NOREXRegClass)
return &X86::GR16_ABCDRegClass;
} else if (B == &X86::GR8_NOREXRegClass) {
if (A == &X86::GR64RegClass || A == &X86::GR64_NOREXRegClass ||
A == &X86::GR64_NOSPRegClass || A == &X86::GR64_NOREX_NOSPRegClass)
return &X86::GR64_NOREXRegClass;
else if (A == &X86::GR64_ABCDRegClass)
return &X86::GR64_ABCDRegClass;
else if (A == &X86::GR32RegClass || A == &X86::GR32_NOREXRegClass ||
A == &X86::GR32_NOSPRegClass)
return &X86::GR32_NOREXRegClass;
else if (A == &X86::GR32_ABCDRegClass)
return &X86::GR32_ABCDRegClass;
else if (A == &X86::GR16RegClass || A == &X86::GR16_NOREXRegClass)
return &X86::GR16_NOREXRegClass;
else if (A == &X86::GR16_ABCDRegClass)
return &X86::GR16_ABCDRegClass;
}
break;
case 2:
// 8-bit hi
if (B == &X86::GR8_ABCD_HRegClass) {
if (A == &X86::GR64RegClass || A == &X86::GR64_ABCDRegClass ||
A == &X86::GR64_NOREXRegClass ||
A == &X86::GR64_NOSPRegClass ||
A == &X86::GR64_NOREX_NOSPRegClass)
return &X86::GR64_ABCDRegClass;
else if (A == &X86::GR32RegClass || A == &X86::GR32_ABCDRegClass ||
A == &X86::GR32_NOREXRegClass || A == &X86::GR32_NOSPRegClass)
return &X86::GR32_ABCDRegClass;
else if (A == &X86::GR16RegClass || A == &X86::GR16_ABCDRegClass ||
A == &X86::GR16_NOREXRegClass)
return &X86::GR16_ABCDRegClass;
}
break;
case 3:
// 16-bit
if (B == &X86::GR16RegClass) {
if (A->getSize() == 4 || A->getSize() == 8)
return A;
} else if (B == &X86::GR16_ABCDRegClass) {
if (A == &X86::GR64RegClass || A == &X86::GR64_ABCDRegClass ||
A == &X86::GR64_NOREXRegClass ||
A == &X86::GR64_NOSPRegClass ||
A == &X86::GR64_NOREX_NOSPRegClass)
return &X86::GR64_ABCDRegClass;
else if (A == &X86::GR32RegClass || A == &X86::GR32_ABCDRegClass ||
A == &X86::GR32_NOREXRegClass || A == &X86::GR32_NOSPRegClass)
return &X86::GR32_ABCDRegClass;
} else if (B == &X86::GR16_NOREXRegClass) {
if (A == &X86::GR64RegClass || A == &X86::GR64_NOREXRegClass ||
A == &X86::GR64_NOSPRegClass || A == &X86::GR64_NOREX_NOSPRegClass)
return &X86::GR64_NOREXRegClass;
else if (A == &X86::GR64_ABCDRegClass)
return &X86::GR64_ABCDRegClass;
else if (A == &X86::GR32RegClass || A == &X86::GR32_NOREXRegClass ||
A == &X86::GR32_NOSPRegClass)
return &X86::GR32_NOREXRegClass;
else if (A == &X86::GR32_ABCDRegClass)
return &X86::GR64_ABCDRegClass;
}
break;
case 4:
// 32-bit
if (B == &X86::GR32RegClass || B == &X86::GR32_NOSPRegClass) {
if (A->getSize() == 8)
return A;
} else if (B == &X86::GR32_ABCDRegClass) {
if (A == &X86::GR64RegClass || A == &X86::GR64_ABCDRegClass ||
A == &X86::GR64_NOREXRegClass ||
A == &X86::GR64_NOSPRegClass ||
A == &X86::GR64_NOREX_NOSPRegClass)
return &X86::GR64_ABCDRegClass;
} else if (B == &X86::GR32_NOREXRegClass) {
if (A == &X86::GR64RegClass || A == &X86::GR64_NOREXRegClass ||
A == &X86::GR64_NOSPRegClass || A == &X86::GR64_NOREX_NOSPRegClass)
return &X86::GR64_NOREXRegClass;
else if (A == &X86::GR64_ABCDRegClass)
return &X86::GR64_ABCDRegClass;
}
break;
}
return 0;
}
const TargetRegisterClass *
X86RegisterInfo::getPointerRegClass(unsigned Kind) const {
switch (Kind) {
default: llvm_unreachable("Unexpected Kind in getPointerRegClass!");
case 0: // Normal GPRs.
if (TM.getSubtarget<X86Subtarget>().is64Bit())
return &X86::GR64RegClass;
return &X86::GR32RegClass;
case 1: // Normal GRPs except the stack pointer (for encoding reasons).
if (TM.getSubtarget<X86Subtarget>().is64Bit())
return &X86::GR64_NOSPRegClass;
return &X86::GR32_NOSPRegClass;
}
}
const TargetRegisterClass *
X86RegisterInfo::getCrossCopyRegClass(const TargetRegisterClass *RC) const {
if (RC == &X86::CCRRegClass) {
if (Is64Bit)
return &X86::GR64RegClass;
else
return &X86::GR32RegClass;
}
return NULL;
}
const unsigned *
X86RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
bool callsEHReturn = false;
if (MF) {
const MachineFrameInfo *MFI = MF->getFrameInfo();
const MachineModuleInfo *MMI = MFI->getMachineModuleInfo();
callsEHReturn = (MMI ? MMI->callsEHReturn() : false);
}
static const unsigned CalleeSavedRegs32Bit[] = {
X86::ESI, X86::EDI, X86::EBX, X86::EBP, 0
};
static const unsigned CalleeSavedRegs32EHRet[] = {
X86::EAX, X86::EDX, X86::ESI, X86::EDI, X86::EBX, X86::EBP, 0
};
static const unsigned CalleeSavedRegs64Bit[] = {
X86::RBX, X86::R12, X86::R13, X86::R14, X86::R15, X86::RBP, 0
};
static const unsigned CalleeSavedRegs64EHRet[] = {
X86::RAX, X86::RDX, X86::RBX, X86::R12,
X86::R13, X86::R14, X86::R15, X86::RBP, 0
};
static const unsigned CalleeSavedRegsWin64[] = {
X86::RBX, X86::RBP, X86::RDI, X86::RSI,
X86::R12, X86::R13, X86::R14, X86::R15,
X86::XMM6, X86::XMM7, X86::XMM8, X86::XMM9,
X86::XMM10, X86::XMM11, X86::XMM12, X86::XMM13,
X86::XMM14, X86::XMM15, 0
};
if (Is64Bit) {
if (IsWin64)
return CalleeSavedRegsWin64;
else
return (callsEHReturn ? CalleeSavedRegs64EHRet : CalleeSavedRegs64Bit);
} else {
return (callsEHReturn ? CalleeSavedRegs32EHRet : CalleeSavedRegs32Bit);
}
}
const TargetRegisterClass* const*
X86RegisterInfo::getCalleeSavedRegClasses(const MachineFunction *MF) const {
bool callsEHReturn = false;
if (MF) {
const MachineFrameInfo *MFI = MF->getFrameInfo();
const MachineModuleInfo *MMI = MFI->getMachineModuleInfo();
callsEHReturn = (MMI ? MMI->callsEHReturn() : false);
}
static const TargetRegisterClass * const CalleeSavedRegClasses32Bit[] = {
&X86::GR32RegClass, &X86::GR32RegClass,
&X86::GR32RegClass, &X86::GR32RegClass, 0
};
static const TargetRegisterClass * const CalleeSavedRegClasses32EHRet[] = {
&X86::GR32RegClass, &X86::GR32RegClass,
&X86::GR32RegClass, &X86::GR32RegClass,
&X86::GR32RegClass, &X86::GR32RegClass, 0
};
static const TargetRegisterClass * const CalleeSavedRegClasses64Bit[] = {
&X86::GR64RegClass, &X86::GR64RegClass,
&X86::GR64RegClass, &X86::GR64RegClass,
&X86::GR64RegClass, &X86::GR64RegClass, 0
};
static const TargetRegisterClass * const CalleeSavedRegClasses64EHRet[] = {
&X86::GR64RegClass, &X86::GR64RegClass,
&X86::GR64RegClass, &X86::GR64RegClass,
&X86::GR64RegClass, &X86::GR64RegClass,
&X86::GR64RegClass, &X86::GR64RegClass, 0
};
static const TargetRegisterClass * const CalleeSavedRegClassesWin64[] = {
&X86::GR64RegClass, &X86::GR64RegClass,
&X86::GR64RegClass, &X86::GR64RegClass,
&X86::GR64RegClass, &X86::GR64RegClass,
&X86::GR64RegClass, &X86::GR64RegClass,
&X86::VR128RegClass, &X86::VR128RegClass,
&X86::VR128RegClass, &X86::VR128RegClass,
&X86::VR128RegClass, &X86::VR128RegClass,
&X86::VR128RegClass, &X86::VR128RegClass,
&X86::VR128RegClass, &X86::VR128RegClass, 0
};
if (Is64Bit) {
if (IsWin64)
return CalleeSavedRegClassesWin64;
else
return (callsEHReturn ?
CalleeSavedRegClasses64EHRet : CalleeSavedRegClasses64Bit);
} else {
return (callsEHReturn ?
CalleeSavedRegClasses32EHRet : CalleeSavedRegClasses32Bit);
}
}
BitVector X86RegisterInfo::getReservedRegs(const MachineFunction &MF) const {
BitVector Reserved(getNumRegs());
// Set the stack-pointer register and its aliases as reserved.
Reserved.set(X86::RSP);
Reserved.set(X86::ESP);
Reserved.set(X86::SP);
Reserved.set(X86::SPL);
// Set the frame-pointer register and its aliases as reserved if needed.
if (hasFP(MF)) {
Reserved.set(X86::RBP);
Reserved.set(X86::EBP);
Reserved.set(X86::BP);
Reserved.set(X86::BPL);
}
// Mark the x87 stack registers as reserved, since they don't behave normally
// with respect to liveness. We don't fully model the effects of x87 stack
// pushes and pops after stackification.
Reserved.set(X86::ST0);
Reserved.set(X86::ST1);
Reserved.set(X86::ST2);
Reserved.set(X86::ST3);
Reserved.set(X86::ST4);
Reserved.set(X86::ST5);
Reserved.set(X86::ST6);
Reserved.set(X86::ST7);
return Reserved;
}
//===----------------------------------------------------------------------===//
// Stack Frame Processing methods
//===----------------------------------------------------------------------===//
static unsigned calculateMaxStackAlignment(const MachineFrameInfo *FFI) {
unsigned MaxAlign = 0;
for (int i = FFI->getObjectIndexBegin(),
e = FFI->getObjectIndexEnd(); i != e; ++i) {
if (FFI->isDeadObjectIndex(i))
continue;
unsigned Align = FFI->getObjectAlignment(i);
MaxAlign = std::max(MaxAlign, Align);
}
return MaxAlign;
}
/// 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 X86RegisterInfo::hasFP(const MachineFunction &MF) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
const MachineModuleInfo *MMI = MFI->getMachineModuleInfo();
return (NoFramePointerElim ||
needsStackRealignment(MF) ||
MFI->hasVarSizedObjects() ||
MFI->isFrameAddressTaken() ||
MF.getInfo<X86MachineFunctionInfo>()->getForceFramePointer() ||
(MMI && MMI->callsUnwindInit()));
}
bool X86RegisterInfo::needsStackRealignment(const MachineFunction &MF) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
// FIXME: Currently we don't support stack realignment for functions with
// variable-sized allocas
return (RealignStack &&
(MFI->getMaxAlignment() > StackAlign &&
!MFI->hasVarSizedObjects()));
}
bool X86RegisterInfo::hasReservedCallFrame(MachineFunction &MF) const {
return !MF.getFrameInfo()->hasVarSizedObjects();
}
bool X86RegisterInfo::hasReservedSpillSlot(MachineFunction &MF, unsigned Reg,
int &FrameIdx) const {
if (Reg == FramePtr && hasFP(MF)) {
FrameIdx = MF.getFrameInfo()->getObjectIndexBegin();
return true;
}
return false;
}
int
X86RegisterInfo::getFrameIndexOffset(MachineFunction &MF, int FI) const {
const TargetFrameInfo &TFI = *MF.getTarget().getFrameInfo();
MachineFrameInfo *MFI = MF.getFrameInfo();
int Offset = MFI->getObjectOffset(FI) - TFI.getOffsetOfLocalArea();
uint64_t StackSize = MFI->getStackSize();
if (needsStackRealignment(MF)) {
if (FI < 0) {
// Skip the saved EBP.
Offset += SlotSize;
} else {
unsigned Align = MFI->getObjectAlignment(FI);
assert( (-(Offset + StackSize)) % Align == 0);
Align = 0;
return Offset + StackSize;
}
// FIXME: Support tail calls
} else {
if (!hasFP(MF))
return Offset + StackSize;
// Skip the saved EBP.
Offset += SlotSize;
// Skip the RETADDR move area
X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
int TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
if (TailCallReturnAddrDelta < 0)
Offset -= TailCallReturnAddrDelta;
}
return Offset;
}
void X86RegisterInfo::
eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
if (!hasReservedCallFrame(MF)) {
// If the stack pointer can be changed after prologue, turn the
// adjcallstackup instruction into a 'sub ESP, <amt>' and the
// adjcallstackdown instruction into 'add ESP, <amt>'
// TODO: consider using push / pop instead of sub + store / add
MachineInstr *Old = I;
uint64_t Amount = Old->getOperand(0).getImm();
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.
Amount = (Amount + StackAlign - 1) / StackAlign * StackAlign;
MachineInstr *New = 0;
if (Old->getOpcode() == getCallFrameSetupOpcode()) {
New = BuildMI(MF, Old->getDebugLoc(),
TII.get(Is64Bit ? X86::SUB64ri32 : X86::SUB32ri),
StackPtr)
.addReg(StackPtr)
.addImm(Amount);
} else {
assert(Old->getOpcode() == getCallFrameDestroyOpcode());
// Factor out the amount the callee already popped.
uint64_t CalleeAmt = Old->getOperand(1).getImm();
Amount -= CalleeAmt;
if (Amount) {
unsigned Opc = (Amount < 128) ?
(Is64Bit ? X86::ADD64ri8 : X86::ADD32ri8) :
(Is64Bit ? X86::ADD64ri32 : X86::ADD32ri);
New = BuildMI(MF, Old->getDebugLoc(), TII.get(Opc), StackPtr)
.addReg(StackPtr)
.addImm(Amount);
}
}
if (New) {
// The EFLAGS implicit def is dead.
New->getOperand(3).setIsDead();
// Replace the pseudo instruction with a new instruction.
MBB.insert(I, New);
}
}
} else if (I->getOpcode() == getCallFrameDestroyOpcode()) {
// If we are performing frame pointer elimination and if the callee pops
// something off the stack pointer, add it back. We do this until we have
// more advanced stack pointer tracking ability.
if (uint64_t CalleeAmt = I->getOperand(1).getImm()) {
unsigned Opc = (CalleeAmt < 128) ?
(Is64Bit ? X86::SUB64ri8 : X86::SUB32ri8) :
(Is64Bit ? X86::SUB64ri32 : X86::SUB32ri);
MachineInstr *Old = I;
MachineInstr *New =
BuildMI(MF, Old->getDebugLoc(), TII.get(Opc),
StackPtr)
.addReg(StackPtr)
.addImm(CalleeAmt);
// The EFLAGS implicit def is dead.
New->getOperand(3).setIsDead();
MBB.insert(I, New);
}
}
MBB.erase(I);
}
void X86RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
int SPAdj, RegScavenger *RS) const{
assert(SPAdj == 0 && "Unexpected");
unsigned i = 0;
MachineInstr &MI = *II;
MachineFunction &MF = *MI.getParent()->getParent();
while (!MI.getOperand(i).isFI()) {
++i;
assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
}
int FrameIndex = MI.getOperand(i).getIndex();
unsigned BasePtr;
if (needsStackRealignment(MF))
BasePtr = (FrameIndex < 0 ? FramePtr : StackPtr);
else
BasePtr = (hasFP(MF) ? FramePtr : StackPtr);
// This must be part of a four operand memory reference. Replace the
// FrameIndex with base register with EBP. Add an offset to the offset.
MI.getOperand(i).ChangeToRegister(BasePtr, false);
// Now add the frame object offset to the offset from EBP.
if (MI.getOperand(i+3).isImm()) {
// Offset is a 32-bit integer.
int Offset = getFrameIndexOffset(MF, FrameIndex) +
(int)(MI.getOperand(i + 3).getImm());
MI.getOperand(i + 3).ChangeToImmediate(Offset);
} else {
// Offset is symbolic. This is extremely rare.
uint64_t Offset = getFrameIndexOffset(MF, FrameIndex) +
(uint64_t)MI.getOperand(i+3).getOffset();
MI.getOperand(i+3).setOffset(Offset);
}
}
void
X86RegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
RegScavenger *RS) const {
MachineFrameInfo *MFI = MF.getFrameInfo();
// Calculate and set max stack object alignment early, so we can decide
// whether we will need stack realignment (and thus FP).
unsigned MaxAlign = std::max(MFI->getMaxAlignment(),
calculateMaxStackAlignment(MFI));
MFI->setMaxAlignment(MaxAlign);
X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
int32_t TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
if (TailCallReturnAddrDelta < 0) {
// create RETURNADDR area
// arg
// arg
// RETADDR
// { ...
// RETADDR area
// ...
// }
// [EBP]
MFI->CreateFixedObject(-TailCallReturnAddrDelta,
(-1U*SlotSize)+TailCallReturnAddrDelta);
}
if (hasFP(MF)) {
assert((TailCallReturnAddrDelta <= 0) &&
"The Delta should always be zero or negative");
const TargetFrameInfo &TFI = *MF.getTarget().getFrameInfo();
// Create a frame entry for the EBP register that must be saved.
int FrameIdx = MFI->CreateFixedObject(SlotSize,
-(int)SlotSize +
TFI.getOffsetOfLocalArea() +
TailCallReturnAddrDelta);
assert(FrameIdx == MFI->getObjectIndexBegin() &&
"Slot for EBP register must be last in order to be found!");
FrameIdx = 0;
}
}
/// emitSPUpdate - Emit a series of instructions to increment / decrement the
/// stack pointer by a constant value.
static
void emitSPUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
unsigned StackPtr, int64_t NumBytes, bool Is64Bit,
const TargetInstrInfo &TII) {
bool isSub = NumBytes < 0;
uint64_t Offset = isSub ? -NumBytes : NumBytes;
unsigned Opc = isSub
? ((Offset < 128) ?
(Is64Bit ? X86::SUB64ri8 : X86::SUB32ri8) :
(Is64Bit ? X86::SUB64ri32 : X86::SUB32ri))
: ((Offset < 128) ?
(Is64Bit ? X86::ADD64ri8 : X86::ADD32ri8) :
(Is64Bit ? X86::ADD64ri32 : X86::ADD32ri));
uint64_t Chunk = (1LL << 31) - 1;
DebugLoc DL = (MBBI != MBB.end() ? MBBI->getDebugLoc() :
DebugLoc::getUnknownLoc());
while (Offset) {
uint64_t ThisVal = (Offset > Chunk) ? Chunk : Offset;
MachineInstr *MI =
BuildMI(MBB, MBBI, DL, TII.get(Opc), StackPtr)
.addReg(StackPtr)
.addImm(ThisVal);
MI->getOperand(3).setIsDead(); // The EFLAGS implicit def is dead.
Offset -= ThisVal;
}
}
/// mergeSPUpdatesUp - Merge two stack-manipulating instructions upper iterator.
static
void mergeSPUpdatesUp(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
unsigned StackPtr, uint64_t *NumBytes = NULL) {
if (MBBI == MBB.begin()) return;
MachineBasicBlock::iterator PI = prior(MBBI);
unsigned Opc = PI->getOpcode();
if ((Opc == X86::ADD64ri32 || Opc == X86::ADD64ri8 ||
Opc == X86::ADD32ri || Opc == X86::ADD32ri8) &&
PI->getOperand(0).getReg() == StackPtr) {
if (NumBytes)
*NumBytes += PI->getOperand(2).getImm();
MBB.erase(PI);
} else if ((Opc == X86::SUB64ri32 || Opc == X86::SUB64ri8 ||
Opc == X86::SUB32ri || Opc == X86::SUB32ri8) &&
PI->getOperand(0).getReg() == StackPtr) {
if (NumBytes)
*NumBytes -= PI->getOperand(2).getImm();
MBB.erase(PI);
}
}
/// mergeSPUpdatesUp - Merge two stack-manipulating instructions lower iterator.
static
void mergeSPUpdatesDown(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI,
unsigned StackPtr, uint64_t *NumBytes = NULL) {
// FIXME: THIS ISN'T RUN!!!
return;
if (MBBI == MBB.end()) return;
MachineBasicBlock::iterator NI = next(MBBI);
if (NI == MBB.end()) return;
unsigned Opc = NI->getOpcode();
if ((Opc == X86::ADD64ri32 || Opc == X86::ADD64ri8 ||
Opc == X86::ADD32ri || Opc == X86::ADD32ri8) &&
NI->getOperand(0).getReg() == StackPtr) {
if (NumBytes)
*NumBytes -= NI->getOperand(2).getImm();
MBB.erase(NI);
MBBI = NI;
} else if ((Opc == X86::SUB64ri32 || Opc == X86::SUB64ri8 ||
Opc == X86::SUB32ri || Opc == X86::SUB32ri8) &&
NI->getOperand(0).getReg() == StackPtr) {
if (NumBytes)
*NumBytes += NI->getOperand(2).getImm();
MBB.erase(NI);
MBBI = NI;
}
}
/// mergeSPUpdates - Checks the instruction before/after the passed
/// instruction. If it is an ADD/SUB instruction it is deleted argument and the
/// stack adjustment is returned as a positive value for ADD and a negative for
/// SUB.
static int mergeSPUpdates(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI,
unsigned StackPtr,
bool doMergeWithPrevious) {
if ((doMergeWithPrevious && MBBI == MBB.begin()) ||
(!doMergeWithPrevious && MBBI == MBB.end()))
return 0;
MachineBasicBlock::iterator PI = doMergeWithPrevious ? prior(MBBI) : MBBI;
MachineBasicBlock::iterator NI = doMergeWithPrevious ? 0 : next(MBBI);
unsigned Opc = PI->getOpcode();
int Offset = 0;
if ((Opc == X86::ADD64ri32 || Opc == X86::ADD64ri8 ||
Opc == X86::ADD32ri || Opc == X86::ADD32ri8) &&
PI->getOperand(0).getReg() == StackPtr){
Offset += PI->getOperand(2).getImm();
MBB.erase(PI);
if (!doMergeWithPrevious) MBBI = NI;
} else if ((Opc == X86::SUB64ri32 || Opc == X86::SUB64ri8 ||
Opc == X86::SUB32ri || Opc == X86::SUB32ri8) &&
PI->getOperand(0).getReg() == StackPtr) {
Offset -= PI->getOperand(2).getImm();
MBB.erase(PI);
if (!doMergeWithPrevious) MBBI = NI;
}
return Offset;
}
void X86RegisterInfo::emitCalleeSavedFrameMoves(MachineFunction &MF,
unsigned LabelId,
unsigned FramePtr) const {
MachineFrameInfo *MFI = MF.getFrameInfo();
MachineModuleInfo *MMI = MFI->getMachineModuleInfo();
if (!MMI) return;
// Add callee saved registers to move list.
const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
if (CSI.empty()) return;
std::vector<MachineMove> &Moves = MMI->getFrameMoves();
const TargetData *TD = MF.getTarget().getTargetData();
bool HasFP = hasFP(MF);
// Calculate amount of bytes used for return address storing.
int stackGrowth =
(MF.getTarget().getFrameInfo()->getStackGrowthDirection() ==
TargetFrameInfo::StackGrowsUp ?
TD->getPointerSize() : -TD->getPointerSize());
// FIXME: This is dirty hack. The code itself is pretty mess right now.
// It should be rewritten from scratch and generalized sometimes.
// Determine maximum offset (minumum due to stack growth).
int64_t MaxOffset = 0;
for (std::vector<CalleeSavedInfo>::const_iterator
I = CSI.begin(), E = CSI.end(); I != E; ++I)
MaxOffset = std::min(MaxOffset,
MFI->getObjectOffset(I->getFrameIdx()));
// Calculate offsets.
int64_t saveAreaOffset = (HasFP ? 3 : 2) * stackGrowth;
for (std::vector<CalleeSavedInfo>::const_iterator
I = CSI.begin(), E = CSI.end(); I != E; ++I) {
int64_t Offset = MFI->getObjectOffset(I->getFrameIdx());
unsigned Reg = I->getReg();
Offset = MaxOffset - Offset + saveAreaOffset;
// Don't output a new machine move if we're re-saving the frame
// pointer. This happens when the PrologEpilogInserter has inserted an extra
// "PUSH" of the frame pointer -- the "emitPrologue" method automatically
// generates one when frame pointers are used. If we generate a "machine
// move" for this extra "PUSH", the linker will lose track of the fact that
// the frame pointer should have the value of the first "PUSH" when it's
// trying to unwind.
//
// FIXME: This looks inelegant. It's possibly correct, but it's covering up
// another bug. I.e., one where we generate a prolog like this:
//
// pushl %ebp
// movl %esp, %ebp
// pushl %ebp
// pushl %esi
// ...
//
// The immediate re-push of EBP is unnecessary. At the least, it's an
// optimization bug. EBP can be used as a scratch register in certain
// cases, but probably not when we have a frame pointer.
if (HasFP && FramePtr == Reg)
continue;
MachineLocation CSDst(MachineLocation::VirtualFP, Offset);
MachineLocation CSSrc(Reg);
Moves.push_back(MachineMove(LabelId, CSDst, CSSrc));
}
}
/// emitPrologue - Push callee-saved registers onto the stack, which
/// automatically adjust the stack pointer. Adjust the stack pointer to allocate
/// space for local variables. Also emit labels used by the exception handler to
/// generate the exception handling frames.
void X86RegisterInfo::emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front(); // Prologue goes in entry BB.
MachineBasicBlock::iterator MBBI = MBB.begin();
MachineFrameInfo *MFI = MF.getFrameInfo();
const Function *Fn = MF.getFunction();
const X86Subtarget *Subtarget = &MF.getTarget().getSubtarget<X86Subtarget>();
MachineModuleInfo *MMI = MFI->getMachineModuleInfo();
X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
bool needsFrameMoves = (MMI && MMI->hasDebugInfo()) ||
!Fn->doesNotThrow() || UnwindTablesMandatory;
uint64_t MaxAlign = MFI->getMaxAlignment(); // Desired stack alignment.
uint64_t StackSize = MFI->getStackSize(); // Number of bytes to allocate.
bool HasFP = hasFP(MF);
DebugLoc DL;
// Add RETADDR move area to callee saved frame size.
int TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
if (TailCallReturnAddrDelta < 0)
X86FI->setCalleeSavedFrameSize(
X86FI->getCalleeSavedFrameSize() - TailCallReturnAddrDelta);
// If this is x86-64 and the Red Zone is not disabled, if we are a leaf
// function, and use up to 128 bytes of stack space, don't have a frame
// pointer, calls, or dynamic alloca then we do not need to adjust the
// stack pointer (we fit in the Red Zone).
if (Is64Bit && !Fn->hasFnAttr(Attribute::NoRedZone) &&
!needsStackRealignment(MF) &&
!MFI->hasVarSizedObjects() && // No dynamic alloca.
!MFI->hasCalls() && // No calls.
!Subtarget->isTargetWin64()) { // Win64 has no Red Zone
uint64_t MinSize = X86FI->getCalleeSavedFrameSize();
if (HasFP) MinSize += SlotSize;
StackSize = std::max(MinSize, StackSize > 128 ? StackSize - 128 : 0);
MFI->setStackSize(StackSize);
} else if (Subtarget->isTargetWin64()) {
// We need to always allocate 32 bytes as register spill area.
// FIXME: We might reuse these 32 bytes for leaf functions.
StackSize += 32;
MFI->setStackSize(StackSize);
}
// Insert stack pointer adjustment for later moving of return addr. Only
// applies to tail call optimized functions where the callee argument stack
// size is bigger than the callers.
if (TailCallReturnAddrDelta < 0) {
MachineInstr *MI =
BuildMI(MBB, MBBI, DL, TII.get(Is64Bit? X86::SUB64ri32 : X86::SUB32ri),
StackPtr)
.addReg(StackPtr)
.addImm(-TailCallReturnAddrDelta);
MI->getOperand(3).setIsDead(); // The EFLAGS implicit def is dead.
}
// Mapping for machine moves:
//
// DST: VirtualFP AND
// SRC: VirtualFP => DW_CFA_def_cfa_offset
// ELSE => DW_CFA_def_cfa
//
// SRC: VirtualFP AND
// DST: Register => DW_CFA_def_cfa_register
//
// ELSE
// OFFSET < 0 => DW_CFA_offset_extended_sf
// REG < 64 => DW_CFA_offset + Reg
// ELSE => DW_CFA_offset_extended
std::vector<MachineMove> &Moves = MMI->getFrameMoves();
const TargetData *TD = MF.getTarget().getTargetData();
uint64_t NumBytes = 0;
int stackGrowth =
(MF.getTarget().getFrameInfo()->getStackGrowthDirection() ==
TargetFrameInfo::StackGrowsUp ?
TD->getPointerSize() : -TD->getPointerSize());
if (HasFP) {
// Calculate required stack adjustment.
uint64_t FrameSize = StackSize - SlotSize;
if (needsStackRealignment(MF))
FrameSize = (FrameSize + MaxAlign - 1) / MaxAlign * MaxAlign;
NumBytes = FrameSize - X86FI->getCalleeSavedFrameSize();
// Get the offset of the stack slot for the EBP register, which is
// guaranteed to be the last slot by processFunctionBeforeFrameFinalized.
// Update the frame offset adjustment.
MFI->setOffsetAdjustment(-NumBytes);
// Save EBP/RBP into the appropriate stack slot.
BuildMI(MBB, MBBI, DL, TII.get(Is64Bit ? X86::PUSH64r : X86::PUSH32r))
.addReg(FramePtr, RegState::Kill);
if (needsFrameMoves) {
// Mark the place where EBP/RBP was saved.
unsigned FrameLabelId = MMI->NextLabelID();
BuildMI(MBB, MBBI, DL, TII.get(X86::DBG_LABEL)).addImm(FrameLabelId);
// Define the current CFA rule to use the provided offset.
if (StackSize) {
MachineLocation SPDst(MachineLocation::VirtualFP);
MachineLocation SPSrc(MachineLocation::VirtualFP, 2 * stackGrowth);
Moves.push_back(MachineMove(FrameLabelId, SPDst, SPSrc));
} else {
// FIXME: Verify & implement for FP
MachineLocation SPDst(StackPtr);
MachineLocation SPSrc(StackPtr, stackGrowth);
Moves.push_back(MachineMove(FrameLabelId, SPDst, SPSrc));
}
// Change the rule for the FramePtr to be an "offset" rule.
MachineLocation FPDst(MachineLocation::VirtualFP,
2 * stackGrowth);
MachineLocation FPSrc(FramePtr);
Moves.push_back(MachineMove(FrameLabelId, FPDst, FPSrc));
}
// Update EBP with the new base value...
BuildMI(MBB, MBBI, DL,
TII.get(Is64Bit ? X86::MOV64rr : X86::MOV32rr), FramePtr)
.addReg(StackPtr);
if (needsFrameMoves) {
// Mark effective beginning of when frame pointer becomes valid.
unsigned FrameLabelId = MMI->NextLabelID();
BuildMI(MBB, MBBI, DL, TII.get(X86::DBG_LABEL)).addImm(FrameLabelId);
// Define the current CFA to use the EBP/RBP register.
MachineLocation FPDst(FramePtr);
MachineLocation FPSrc(MachineLocation::VirtualFP);
Moves.push_back(MachineMove(FrameLabelId, FPDst, FPSrc));
}
// Mark the FramePtr as live-in in every block except the entry.
for (MachineFunction::iterator I = next(MF.begin()), E = MF.end();
I != E; ++I)
I->addLiveIn(FramePtr);
// Realign stack
if (needsStackRealignment(MF)) {
MachineInstr *MI =
BuildMI(MBB, MBBI, DL,
TII.get(Is64Bit ? X86::AND64ri32 : X86::AND32ri),
StackPtr).addReg(StackPtr).addImm(-MaxAlign);
// The EFLAGS implicit def is dead.
MI->getOperand(3).setIsDead();
}
} else {
NumBytes = StackSize - X86FI->getCalleeSavedFrameSize();
}
// Skip the callee-saved push instructions.
bool PushedRegs = false;
int StackOffset = 2 * stackGrowth;
while (MBBI != MBB.end() &&
(MBBI->getOpcode() == X86::PUSH32r ||
MBBI->getOpcode() == X86::PUSH64r)) {
PushedRegs = true;
++MBBI;
if (!HasFP && needsFrameMoves) {
// Mark callee-saved push instruction.
unsigned LabelId = MMI->NextLabelID();
BuildMI(MBB, MBBI, DL, TII.get(X86::DBG_LABEL)).addImm(LabelId);
// Define the current CFA rule to use the provided offset.
unsigned Ptr = StackSize ?
MachineLocation::VirtualFP : StackPtr;
MachineLocation SPDst(Ptr);
MachineLocation SPSrc(Ptr, StackOffset);
Moves.push_back(MachineMove(LabelId, SPDst, SPSrc));
StackOffset += stackGrowth;
}
}
if (MBBI != MBB.end())
DL = MBBI->getDebugLoc();
// Adjust stack pointer: ESP -= numbytes.
if (NumBytes >= 4096 && Subtarget->isTargetCygMing()) {
// Check, whether EAX is livein for this function.
bool isEAXAlive = false;
for (MachineRegisterInfo::livein_iterator
II = MF.getRegInfo().livein_begin(),
EE = MF.getRegInfo().livein_end(); (II != EE) && !isEAXAlive; ++II) {
unsigned Reg = II->first;
isEAXAlive = (Reg == X86::EAX || Reg == X86::AX ||
Reg == X86::AH || Reg == X86::AL);
}
// Function prologue calls _alloca to probe the stack when allocating more
// than 4k bytes in one go. Touching the stack at 4K increments is necessary
// to ensure that the guard pages used by the OS virtual memory manager are
// allocated in correct sequence.
if (!isEAXAlive) {
BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32ri), X86::EAX)
.addImm(NumBytes);
BuildMI(MBB, MBBI, DL, TII.get(X86::CALLpcrel32))
.addExternalSymbol("_alloca");
} else {
// Save EAX
BuildMI(MBB, MBBI, DL, TII.get(X86::PUSH32r))
.addReg(X86::EAX, RegState::Kill);
// Allocate NumBytes-4 bytes on stack. We'll also use 4 already
// allocated bytes for EAX.
BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32ri), X86::EAX)
.addImm(NumBytes - 4);
BuildMI(MBB, MBBI, DL, TII.get(X86::CALLpcrel32))
.addExternalSymbol("_alloca");
// Restore EAX
MachineInstr *MI = addRegOffset(BuildMI(MF, DL, TII.get(X86::MOV32rm),
X86::EAX),
StackPtr, false, NumBytes - 4);
MBB.insert(MBBI, MI);
}
} else if (NumBytes) {
// If there is an SUB32ri of ESP immediately before this instruction, merge
// the two. This can be the case when tail call elimination is enabled and
// the callee has more arguments then the caller.
NumBytes -= mergeSPUpdates(MBB, MBBI, StackPtr, true);
// If there is an ADD32ri or SUB32ri of ESP immediately after this
// instruction, merge the two instructions.
mergeSPUpdatesDown(MBB, MBBI, StackPtr, &NumBytes);
if (NumBytes)
emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit, TII);
}
if ((NumBytes || PushedRegs) && needsFrameMoves) {
// Mark end of stack pointer adjustment.
unsigned LabelId = MMI->NextLabelID();
BuildMI(MBB, MBBI, DL, TII.get(X86::DBG_LABEL)).addImm(LabelId);
if (!HasFP && NumBytes) {
// Define the current CFA rule to use the provided offset.
if (StackSize) {
MachineLocation SPDst(MachineLocation::VirtualFP);
MachineLocation SPSrc(MachineLocation::VirtualFP,
-StackSize + stackGrowth);
Moves.push_back(MachineMove(LabelId, SPDst, SPSrc));
} else {
// FIXME: Verify & implement for FP
MachineLocation SPDst(StackPtr);
MachineLocation SPSrc(StackPtr, stackGrowth);
Moves.push_back(MachineMove(LabelId, SPDst, SPSrc));
}
}
// Emit DWARF info specifying the offsets of the callee-saved registers.
if (PushedRegs)
emitCalleeSavedFrameMoves(MF, LabelId, HasFP ? FramePtr : StackPtr);
}
}
void X86RegisterInfo::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
MachineBasicBlock::iterator MBBI = prior(MBB.end());
unsigned RetOpcode = MBBI->getOpcode();
DebugLoc DL = MBBI->getDebugLoc();
switch (RetOpcode) {
default:
llvm_unreachable("Can only insert epilog into returning blocks");
case X86::RET:
case X86::RETI:
case X86::TCRETURNdi:
case X86::TCRETURNri:
case X86::TCRETURNri64:
case X86::TCRETURNdi64:
case X86::EH_RETURN:
case X86::EH_RETURN64:
case X86::TAILJMPd:
case X86::TAILJMPr:
case X86::TAILJMPm:
break; // These are ok
}
// Get the number of bytes to allocate from the FrameInfo.
uint64_t StackSize = MFI->getStackSize();
uint64_t MaxAlign = MFI->getMaxAlignment();
unsigned CSSize = X86FI->getCalleeSavedFrameSize();
uint64_t NumBytes = 0;
if (hasFP(MF)) {
// Calculate required stack adjustment.
uint64_t FrameSize = StackSize - SlotSize;
if (needsStackRealignment(MF))
FrameSize = (FrameSize + MaxAlign - 1)/MaxAlign*MaxAlign;
NumBytes = FrameSize - CSSize;
// Pop EBP.
BuildMI(MBB, MBBI, DL,
TII.get(Is64Bit ? X86::POP64r : X86::POP32r), FramePtr);
} else {
NumBytes = StackSize - CSSize;
}
// Skip the callee-saved pop instructions.
MachineBasicBlock::iterator LastCSPop = MBBI;
while (MBBI != MBB.begin()) {
MachineBasicBlock::iterator PI = prior(MBBI);
unsigned Opc = PI->getOpcode();
if (Opc != X86::POP32r && Opc != X86::POP64r &&
!PI->getDesc().isTerminator())
break;
--MBBI;
}
DL = MBBI->getDebugLoc();
// If there is an ADD32ri or SUB32ri of ESP immediately before this
// instruction, merge the two instructions.
if (NumBytes || MFI->hasVarSizedObjects())
mergeSPUpdatesUp(MBB, MBBI, StackPtr, &NumBytes);
// If dynamic alloca is used, then reset esp to point to the last callee-saved
// slot before popping them off! Same applies for the case, when stack was
// realigned.
if (needsStackRealignment(MF)) {
// We cannot use LEA here, because stack pointer was realigned. We need to
// deallocate local frame back.
if (CSSize) {
emitSPUpdate(MBB, MBBI, StackPtr, NumBytes, Is64Bit, TII);
MBBI = prior(LastCSPop);
}
BuildMI(MBB, MBBI, DL,
TII.get(Is64Bit ? X86::MOV64rr : X86::MOV32rr),
StackPtr).addReg(FramePtr);
} else if (MFI->hasVarSizedObjects()) {
if (CSSize) {
unsigned Opc = Is64Bit ? X86::LEA64r : X86::LEA32r;
MachineInstr *MI =
addLeaRegOffset(BuildMI(MF, DL, TII.get(Opc), StackPtr),
FramePtr, false, -CSSize);
MBB.insert(MBBI, MI);
} else {
BuildMI(MBB, MBBI, DL,
TII.get(Is64Bit ? X86::MOV64rr : X86::MOV32rr), StackPtr)
.addReg(FramePtr);
}
} else if (NumBytes) {
// Adjust stack pointer back: ESP += numbytes.
emitSPUpdate(MBB, MBBI, StackPtr, NumBytes, Is64Bit, TII);
}
// We're returning from function via eh_return.
if (RetOpcode == X86::EH_RETURN || RetOpcode == X86::EH_RETURN64) {
MBBI = prior(MBB.end());
MachineOperand &DestAddr = MBBI->getOperand(0);
assert(DestAddr.isReg() && "Offset should be in register!");
BuildMI(MBB, MBBI, DL,
TII.get(Is64Bit ? X86::MOV64rr : X86::MOV32rr),
StackPtr).addReg(DestAddr.getReg());
} else if (RetOpcode == X86::TCRETURNri || RetOpcode == X86::TCRETURNdi ||
RetOpcode== X86::TCRETURNri64 || RetOpcode == X86::TCRETURNdi64) {
// Tail call return: adjust the stack pointer and jump to callee.
MBBI = prior(MBB.end());
MachineOperand &JumpTarget = MBBI->getOperand(0);
MachineOperand &StackAdjust = MBBI->getOperand(1);
assert(StackAdjust.isImm() && "Expecting immediate value.");
// Adjust stack pointer.
int StackAdj = StackAdjust.getImm();
int MaxTCDelta = X86FI->getTCReturnAddrDelta();
int Offset = 0;
assert(MaxTCDelta <= 0 && "MaxTCDelta should never be positive");
// Incoporate the retaddr area.
Offset = StackAdj-MaxTCDelta;
assert(Offset >= 0 && "Offset should never be negative");
if (Offset) {
// Check for possible merge with preceeding ADD instruction.
Offset += mergeSPUpdates(MBB, MBBI, StackPtr, true);
emitSPUpdate(MBB, MBBI, StackPtr, Offset, Is64Bit, TII);
}
// Jump to label or value in register.
if (RetOpcode == X86::TCRETURNdi|| RetOpcode == X86::TCRETURNdi64)
BuildMI(MBB, MBBI, DL, TII.get(X86::TAILJMPd)).
addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset());
else if (RetOpcode== X86::TCRETURNri64)
BuildMI(MBB, MBBI, DL, TII.get(X86::TAILJMPr64), JumpTarget.getReg());
else
BuildMI(MBB, MBBI, DL, TII.get(X86::TAILJMPr), JumpTarget.getReg());
// Delete the pseudo instruction TCRETURN.
MBB.erase(MBBI);
} else if ((RetOpcode == X86::RET || RetOpcode == X86::RETI) &&
(X86FI->getTCReturnAddrDelta() < 0)) {
// Add the return addr area delta back since we are not tail calling.
int delta = -1*X86FI->getTCReturnAddrDelta();
MBBI = prior(MBB.end());
// Check for possible merge with preceeding ADD instruction.
delta += mergeSPUpdates(MBB, MBBI, StackPtr, true);
emitSPUpdate(MBB, MBBI, StackPtr, delta, Is64Bit, TII);
}
}
unsigned X86RegisterInfo::getRARegister() const {
return Is64Bit ? X86::RIP // Should have dwarf #16.
: X86::EIP; // Should have dwarf #8.
}
unsigned X86RegisterInfo::getFrameRegister(MachineFunction &MF) const {
return hasFP(MF) ? FramePtr : StackPtr;
}
void
X86RegisterInfo::getInitialFrameState(std::vector<MachineMove> &Moves) const {
// Calculate amount of bytes used for return address storing
int stackGrowth = (Is64Bit ? -8 : -4);
// Initial state of the frame pointer is esp+4.
MachineLocation Dst(MachineLocation::VirtualFP);
MachineLocation Src(StackPtr, stackGrowth);
Moves.push_back(MachineMove(0, Dst, Src));
// Add return address to move list
MachineLocation CSDst(StackPtr, stackGrowth);
MachineLocation CSSrc(getRARegister());
Moves.push_back(MachineMove(0, CSDst, CSSrc));
}
unsigned X86RegisterInfo::getEHExceptionRegister() const {
llvm_unreachable("What is the exception register");
return 0;
}
unsigned X86RegisterInfo::getEHHandlerRegister() const {
llvm_unreachable("What is the exception handler register");
return 0;
}
namespace llvm {
unsigned getX86SubSuperRegister(unsigned Reg, EVT VT, bool High) {
switch (VT.getSimpleVT().SimpleTy) {
default: return Reg;
case MVT::i8:
if (High) {
switch (Reg) {
default: return 0;
case X86::AH: case X86::AL: case X86::AX: case X86::EAX: case X86::RAX:
return X86::AH;
case X86::DH: case X86::DL: case X86::DX: case X86::EDX: case X86::RDX:
return X86::DH;
case X86::CH: case X86::CL: case X86::CX: case X86::ECX: case X86::RCX:
return X86::CH;
case X86::BH: case X86::BL: case X86::BX: case X86::EBX: case X86::RBX:
return X86::BH;
}
} else {
switch (Reg) {
default: return 0;
case X86::AH: case X86::AL: case X86::AX: case X86::EAX: case X86::RAX:
return X86::AL;
case X86::DH: case X86::DL: case X86::DX: case X86::EDX: case X86::RDX:
return X86::DL;
case X86::CH: case X86::CL: case X86::CX: case X86::ECX: case X86::RCX:
return X86::CL;
case X86::BH: case X86::BL: case X86::BX: case X86::EBX: case X86::RBX:
return X86::BL;
case X86::SIL: case X86::SI: case X86::ESI: case X86::RSI:
return X86::SIL;
case X86::DIL: case X86::DI: case X86::EDI: case X86::RDI:
return X86::DIL;
case X86::BPL: case X86::BP: case X86::EBP: case X86::RBP:
return X86::BPL;
case X86::SPL: case X86::SP: case X86::ESP: case X86::RSP:
return X86::SPL;
case X86::R8B: case X86::R8W: case X86::R8D: case X86::R8:
return X86::R8B;
case X86::R9B: case X86::R9W: case X86::R9D: case X86::R9:
return X86::R9B;
case X86::R10B: case X86::R10W: case X86::R10D: case X86::R10:
return X86::R10B;
case X86::R11B: case X86::R11W: case X86::R11D: case X86::R11:
return X86::R11B;
case X86::R12B: case X86::R12W: case X86::R12D: case X86::R12:
return X86::R12B;
case X86::R13B: case X86::R13W: case X86::R13D: case X86::R13:
return X86::R13B;
case X86::R14B: case X86::R14W: case X86::R14D: case X86::R14:
return X86::R14B;
case X86::R15B: case X86::R15W: case X86::R15D: case X86::R15:
return X86::R15B;
}
}
case MVT::i16:
switch (Reg) {
default: return Reg;
case X86::AH: case X86::AL: case X86::AX: case X86::EAX: case X86::RAX:
return X86::AX;
case X86::DH: case X86::DL: case X86::DX: case X86::EDX: case X86::RDX:
return X86::DX;
case X86::CH: case X86::CL: case X86::CX: case X86::ECX: case X86::RCX:
return X86::CX;
case X86::BH: case X86::BL: case X86::BX: case X86::EBX: case X86::RBX:
return X86::BX;
case X86::SIL: case X86::SI: case X86::ESI: case X86::RSI:
return X86::SI;
case X86::DIL: case X86::DI: case X86::EDI: case X86::RDI:
return X86::DI;
case X86::BPL: case X86::BP: case X86::EBP: case X86::RBP:
return X86::BP;
case X86::SPL: case X86::SP: case X86::ESP: case X86::RSP:
return X86::SP;
case X86::R8B: case X86::R8W: case X86::R8D: case X86::R8:
return X86::R8W;
case X86::R9B: case X86::R9W: case X86::R9D: case X86::R9:
return X86::R9W;
case X86::R10B: case X86::R10W: case X86::R10D: case X86::R10:
return X86::R10W;
case X86::R11B: case X86::R11W: case X86::R11D: case X86::R11:
return X86::R11W;
case X86::R12B: case X86::R12W: case X86::R12D: case X86::R12:
return X86::R12W;
case X86::R13B: case X86::R13W: case X86::R13D: case X86::R13:
return X86::R13W;
case X86::R14B: case X86::R14W: case X86::R14D: case X86::R14:
return X86::R14W;
case X86::R15B: case X86::R15W: case X86::R15D: case X86::R15:
return X86::R15W;
}
case MVT::i32:
switch (Reg) {
default: return Reg;
case X86::AH: case X86::AL: case X86::AX: case X86::EAX: case X86::RAX:
return X86::EAX;
case X86::DH: case X86::DL: case X86::DX: case X86::EDX: case X86::RDX:
return X86::EDX;
case X86::CH: case X86::CL: case X86::CX: case X86::ECX: case X86::RCX:
return X86::ECX;
case X86::BH: case X86::BL: case X86::BX: case X86::EBX: case X86::RBX:
return X86::EBX;
case X86::SIL: case X86::SI: case X86::ESI: case X86::RSI:
return X86::ESI;
case X86::DIL: case X86::DI: case X86::EDI: case X86::RDI:
return X86::EDI;
case X86::BPL: case X86::BP: case X86::EBP: case X86::RBP:
return X86::EBP;
case X86::SPL: case X86::SP: case X86::ESP: case X86::RSP:
return X86::ESP;
case X86::R8B: case X86::R8W: case X86::R8D: case X86::R8:
return X86::R8D;
case X86::R9B: case X86::R9W: case X86::R9D: case X86::R9:
return X86::R9D;
case X86::R10B: case X86::R10W: case X86::R10D: case X86::R10:
return X86::R10D;
case X86::R11B: case X86::R11W: case X86::R11D: case X86::R11:
return X86::R11D;
case X86::R12B: case X86::R12W: case X86::R12D: case X86::R12:
return X86::R12D;
case X86::R13B: case X86::R13W: case X86::R13D: case X86::R13:
return X86::R13D;
case X86::R14B: case X86::R14W: case X86::R14D: case X86::R14:
return X86::R14D;
case X86::R15B: case X86::R15W: case X86::R15D: case X86::R15:
return X86::R15D;
}
case MVT::i64:
switch (Reg) {
default: return Reg;
case X86::AH: case X86::AL: case X86::AX: case X86::EAX: case X86::RAX:
return X86::RAX;
case X86::DH: case X86::DL: case X86::DX: case X86::EDX: case X86::RDX:
return X86::RDX;
case X86::CH: case X86::CL: case X86::CX: case X86::ECX: case X86::RCX:
return X86::RCX;
case X86::BH: case X86::BL: case X86::BX: case X86::EBX: case X86::RBX:
return X86::RBX;
case X86::SIL: case X86::SI: case X86::ESI: case X86::RSI:
return X86::RSI;
case X86::DIL: case X86::DI: case X86::EDI: case X86::RDI:
return X86::RDI;
case X86::BPL: case X86::BP: case X86::EBP: case X86::RBP:
return X86::RBP;
case X86::SPL: case X86::SP: case X86::ESP: case X86::RSP:
return X86::RSP;
case X86::R8B: case X86::R8W: case X86::R8D: case X86::R8:
return X86::R8;
case X86::R9B: case X86::R9W: case X86::R9D: case X86::R9:
return X86::R9;
case X86::R10B: case X86::R10W: case X86::R10D: case X86::R10:
return X86::R10;
case X86::R11B: case X86::R11W: case X86::R11D: case X86::R11:
return X86::R11;
case X86::R12B: case X86::R12W: case X86::R12D: case X86::R12:
return X86::R12;
case X86::R13B: case X86::R13W: case X86::R13D: case X86::R13:
return X86::R13;
case X86::R14B: case X86::R14W: case X86::R14D: case X86::R14:
return X86::R14;
case X86::R15B: case X86::R15W: case X86::R15D: case X86::R15:
return X86::R15;
}
}
return Reg;
}
}
#include "X86GenRegisterInfo.inc"
namespace {
struct VISIBILITY_HIDDEN MSAC : public MachineFunctionPass {
static char ID;
MSAC() : MachineFunctionPass(&ID) {}
virtual bool runOnMachineFunction(MachineFunction &MF) {
MachineFrameInfo *FFI = MF.getFrameInfo();
MachineRegisterInfo &RI = MF.getRegInfo();
// Calculate max stack alignment of all already allocated stack objects.
unsigned MaxAlign = calculateMaxStackAlignment(FFI);
// Be over-conservative: scan over all vreg defs and find, whether vector
// registers are used. If yes - there is probability, that vector register
// will be spilled and thus stack needs to be aligned properly.
for (unsigned RegNum = TargetRegisterInfo::FirstVirtualRegister;
RegNum < RI.getLastVirtReg(); ++RegNum)
MaxAlign = std::max(MaxAlign, RI.getRegClass(RegNum)->getAlignment());
if (FFI->getMaxAlignment() == MaxAlign)
return false;
FFI->setMaxAlignment(MaxAlign);
return true;
}
virtual const char *getPassName() const {
return "X86 Maximal Stack Alignment Calculator";
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
MachineFunctionPass::getAnalysisUsage(AU);
}
};
char MSAC::ID = 0;
}
FunctionPass*
llvm::createX86MaxStackAlignmentCalculatorPass() { return new MSAC(); }
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