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llvm-6502/lib/Target/X86/X86RegisterInfo.cpp
Dale Johannesen 1532f3ddd7 Recommitting EH patch; this should answer most of the 
review feedback.
-enable-eh is still accepted but doesn't do anything.
EH intrinsics use Dwarf EH if the target supports that,
and are handled by LowerInvoke otherwise.
The separation of the EH table and frame move data is,
I think, logically figured out, but either one still
causes full EH info to be generated (not sure how to
split the metadata correctly).
MachineModuleInfo::needsFrameInfo is no longer used and
is removed.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49064 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-02 00:25:04 +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/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineLocation.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Target/TargetAsmInfo.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"
using namespace llvm;
X86RegisterInfo::X86RegisterInfo(X86TargetMachine &tm,
const TargetInstrInfo &tii)
: X86GenRegisterInfo(X86::ADJCALLSTACKDOWN, X86::ADJCALLSTACKUP),
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) const {
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!");
assert(0 && "Register allocator hasn't allocated reg correctly yet!");
return 0;
}
}
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 {
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 CalleeSavedRegsWin64[] = {
X86::RBX, X86::RBP, X86::RDI, X86::RSI,
X86::R12, X86::R13, X86::R14, X86::R15, 0
};
if (Is64Bit) {
if (IsWin64)
return CalleeSavedRegsWin64;
else
return CalleeSavedRegs64Bit;
} else {
if (MF) {
MachineFrameInfo *MFI = MF->getFrameInfo();
MachineModuleInfo *MMI = MFI->getMachineModuleInfo();
if (MMI && MMI->callsEHReturn())
return CalleeSavedRegs32EHRet;
}
return CalleeSavedRegs32Bit;
}
}
const TargetRegisterClass* const*
X86RegisterInfo::getCalleeSavedRegClasses(const MachineFunction *MF) const {
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 CalleeSavedRegClassesWin64[] = {
&X86::GR64RegClass, &X86::GR64RegClass,
&X86::GR64RegClass, &X86::GR64RegClass,
&X86::GR64RegClass, &X86::GR64RegClass,
&X86::GR64RegClass, &X86::GR64RegClass, 0
};
if (Is64Bit) {
if (IsWin64)
return CalleeSavedRegClassesWin64;
else
return CalleeSavedRegClasses64Bit;
} else {
if (MF) {
MachineFrameInfo *MFI = MF->getFrameInfo();
MachineModuleInfo *MMI = MFI->getMachineModuleInfo();
if (MMI && MMI->callsEHReturn())
return CalleeSavedRegClasses32EHRet;
}
return CalleeSavedRegClasses32Bit;
}
}
BitVector X86RegisterInfo::getReservedRegs(const MachineFunction &MF) const {
BitVector Reserved(getNumRegs());
Reserved.set(X86::RSP);
Reserved.set(X86::ESP);
Reserved.set(X86::SP);
Reserved.set(X86::SPL);
if (hasFP(MF)) {
Reserved.set(X86::RBP);
Reserved.set(X86::EBP);
Reserved.set(X86::BP);
Reserved.set(X86::BPL);
}
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 X86RegisterInfo::hasFP(const MachineFunction &MF) const {
MachineFrameInfo *MFI = MF.getFrameInfo();
MachineModuleInfo *MMI = MFI->getMachineModuleInfo();
return (NoFramePointerElim ||
MFI->hasVarSizedObjects() ||
MF.getInfo<X86MachineFunctionInfo>()->getForceFramePointer() ||
(MMI && MMI->callsUnwindInit()));
}
bool X86RegisterInfo::hasReservedCallFrame(MachineFunction &MF) const {
return !MF.getFrameInfo()->hasVarSizedObjects();
}
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() == X86::ADJCALLSTACKDOWN) {
New=BuildMI(TII.get(Is64Bit ? X86::SUB64ri32 : X86::SUB32ri), StackPtr)
.addReg(StackPtr).addImm(Amount);
} else {
assert(Old->getOpcode() == X86::ADJCALLSTACKUP);
// 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(TII.get(Opc), StackPtr).addReg(StackPtr).addImm(Amount);
}
}
// Replace the pseudo instruction with a new instruction...
if (New) MBB.insert(I, New);
}
} else if (I->getOpcode() == X86::ADJCALLSTACKUP) {
// 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 *New =
BuildMI(TII.get(Opc), StackPtr).addReg(StackPtr).addImm(CalleeAmt);
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).isFrameIndex()) {
++i;
assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
}
int FrameIndex = MI.getOperand(i).getIndex();
// 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(hasFP(MF) ? FramePtr : StackPtr, false);
// Now add the frame object offset to the offset from EBP.
int64_t Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex) +
MI.getOperand(i+3).getImm()+SlotSize;
if (!hasFP(MF))
Offset += MF.getFrameInfo()->getStackSize();
else {
Offset += SlotSize; // Skip the saved EBP
// Skip the RETADDR move area
X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
int TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
if (TailCallReturnAddrDelta < 0) Offset -= TailCallReturnAddrDelta;
}
MI.getOperand(i+3).ChangeToImmediate(Offset);
}
void
X86RegisterInfo::processFunctionBeforeFrameFinalized(MachineFunction &MF) const{
X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
int32_t TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
if (TailCallReturnAddrDelta < 0) {
// create RETURNADDR area
// arg
// arg
// RETADDR
// { ...
// RETADDR area
// ...
// }
// [EBP]
MF.getFrameInfo()->
CreateFixedObject(-TailCallReturnAddrDelta,
(-1*SlotSize)+TailCallReturnAddrDelta);
}
if (hasFP(MF)) {
assert((TailCallReturnAddrDelta <= 0) &&
"The Delta should always be zero or negative");
// Create a frame entry for the EBP register that must be saved.
int FrameIdx = MF.getFrameInfo()->CreateFixedObject(SlotSize,
(int)SlotSize * -2+
TailCallReturnAddrDelta);
assert(FrameIdx == MF.getFrameInfo()->getObjectIndexBegin() &&
"Slot for EBP register must be last in order to be found!");
}
}
/// 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;
while (Offset) {
uint64_t ThisVal = (Offset > Chunk) ? Chunk : Offset;
BuildMI(MBB, MBBI, TII.get(Opc), StackPtr).addReg(StackPtr).addImm(ThisVal);
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) {
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;
int Offset = 0;
MachineBasicBlock::iterator PI = doMergeWithPrevious ? prior(MBBI) : MBBI;
MachineBasicBlock::iterator NI = doMergeWithPrevious ? 0 : next(MBBI);
unsigned Opc = PI->getOpcode();
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::emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB
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>();
MachineBasicBlock::iterator MBBI = MBB.begin();
bool needsFrameInfo = (MMI && MMI->hasDebugInfo()) || !Fn->doesNotThrow();
// Prepare for frame info.
unsigned FrameLabelId = 0;
// Get the number of bytes to allocate from the FrameInfo.
uint64_t StackSize = MFI->getStackSize();
// Add RETADDR move area to callee saved frame size.
int TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
if (TailCallReturnAddrDelta < 0)
X86FI->setCalleeSavedFrameSize(
X86FI->getCalleeSavedFrameSize() +(-TailCallReturnAddrDelta));
uint64_t NumBytes = StackSize - X86FI->getCalleeSavedFrameSize();
// 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) {
BuildMI(MBB, MBBI, TII.get(Is64Bit? X86::SUB64ri32 : X86::SUB32ri),
StackPtr).addReg(StackPtr).addImm(-TailCallReturnAddrDelta);
}
if (hasFP(MF)) {
// 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(SlotSize-NumBytes);
// Save EBP into the appropriate stack slot...
BuildMI(MBB, MBBI, TII.get(Is64Bit ? X86::PUSH64r : X86::PUSH32r))
.addReg(FramePtr);
NumBytes -= SlotSize;
if (needsFrameInfo) {
// Mark effective beginning of when frame pointer becomes valid.
FrameLabelId = MMI->NextLabelID();
BuildMI(MBB, MBBI, TII.get(X86::LABEL)).addImm(FrameLabelId).addImm(0);
}
// Update EBP with the new base value...
BuildMI(MBB, MBBI, TII.get(Is64Bit ? X86::MOV64rr : X86::MOV32rr), FramePtr)
.addReg(StackPtr);
}
unsigned ReadyLabelId = 0;
if (needsFrameInfo) {
// Mark effective beginning of when frame pointer is ready.
ReadyLabelId = MMI->NextLabelID();
BuildMI(MBB, MBBI, TII.get(X86::LABEL)).addImm(ReadyLabelId).addImm(0);
}
// Skip the callee-saved push instructions.
while (MBBI != MBB.end() &&
(MBBI->getOpcode() == X86::PUSH32r ||
MBBI->getOpcode() == X86::PUSH64r))
++MBBI;
if (NumBytes) { // 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, TII.get(X86::MOV32ri), X86::EAX).addImm(NumBytes);
BuildMI(MBB, MBBI, TII.get(X86::CALLpcrel32))
.addExternalSymbol("_alloca");
} else {
// Save EAX
BuildMI(MBB, MBBI, TII.get(X86::PUSH32r), X86::EAX);
// Allocate NumBytes-4 bytes on stack. We'll also use 4 already
// allocated bytes for EAX.
BuildMI(MBB, MBBI, TII.get(X86::MOV32ri), X86::EAX).addImm(NumBytes-4);
BuildMI(MBB, MBBI, TII.get(X86::CALLpcrel32))
.addExternalSymbol("_alloca");
// Restore EAX
MachineInstr *MI = addRegOffset(BuildMI(TII.get(X86::MOV32rm),X86::EAX),
StackPtr, NumBytes-4);
MBB.insert(MBBI, MI);
}
} else {
// 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 (needsFrameInfo) {
std::vector<MachineMove> &Moves = MMI->getFrameMoves();
const TargetData *TD = MF.getTarget().getTargetData();
// Calculate amount of bytes used for return address storing
int stackGrowth =
(MF.getTarget().getFrameInfo()->getStackGrowthDirection() ==
TargetFrameInfo::StackGrowsUp ?
TD->getPointerSize() : -TD->getPointerSize());
if (StackSize) {
// Show update of SP.
if (hasFP(MF)) {
// Adjust SP
MachineLocation SPDst(MachineLocation::VirtualFP);
MachineLocation SPSrc(MachineLocation::VirtualFP, 2*stackGrowth);
Moves.push_back(MachineMove(FrameLabelId, SPDst, SPSrc));
} else {
MachineLocation SPDst(MachineLocation::VirtualFP);
MachineLocation SPSrc(MachineLocation::VirtualFP,
-StackSize+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));
}
// Add callee saved registers to move list.
const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
// 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 (unsigned I = 0, E = CSI.size(); I!=E; ++I)
MaxOffset = std::min(MaxOffset,
MFI->getObjectOffset(CSI[I].getFrameIdx()));
// Calculate offsets
int64_t saveAreaOffset = (hasFP(MF) ? 3 : 2)*stackGrowth;
for (unsigned I = 0, E = CSI.size(); I!=E; ++I) {
int64_t Offset = MFI->getObjectOffset(CSI[I].getFrameIdx());
unsigned Reg = CSI[I].getReg();
Offset = (MaxOffset-Offset+saveAreaOffset);
MachineLocation CSDst(MachineLocation::VirtualFP, Offset);
MachineLocation CSSrc(Reg);
Moves.push_back(MachineMove(FrameLabelId, CSDst, CSSrc));
}
if (hasFP(MF)) {
// Save FP
MachineLocation FPDst(MachineLocation::VirtualFP, 2*stackGrowth);
MachineLocation FPSrc(FramePtr);
Moves.push_back(MachineMove(ReadyLabelId, FPDst, FPSrc));
}
MachineLocation FPDst(hasFP(MF) ? FramePtr : StackPtr);
MachineLocation FPSrc(MachineLocation::VirtualFP);
Moves.push_back(MachineMove(ReadyLabelId, FPDst, FPSrc));
}
// If it's main() on Cygwin\Mingw32 we should align stack as well
if (Fn->hasExternalLinkage() && Fn->getName() == "main" &&
Subtarget->isTargetCygMing()) {
BuildMI(MBB, MBBI, TII.get(X86::AND32ri), X86::ESP)
.addReg(X86::ESP).addImm(-StackAlign);
// Probe the stack
BuildMI(MBB, MBBI, TII.get(X86::MOV32ri), X86::EAX).addImm(StackAlign);
BuildMI(MBB, MBBI, TII.get(X86::CALLpcrel32)).addExternalSymbol("_alloca");
}
}
void X86RegisterInfo::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
const Function* Fn = MF.getFunction();
X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
const X86Subtarget* Subtarget = &MF.getTarget().getSubtarget<X86Subtarget>();
MachineBasicBlock::iterator MBBI = prior(MBB.end());
unsigned RetOpcode = MBBI->getOpcode();
switch (RetOpcode) {
case X86::RET:
case X86::RETI:
case X86::TCRETURNdi:
case X86::TCRETURNri:
case X86::TCRETURNri64:
case X86::TCRETURNdi64:
case X86::EH_RETURN:
case X86::TAILJMPd:
case X86::TAILJMPr:
case X86::TAILJMPm: break; // These are ok
default:
assert(0 && "Can only insert epilog into returning blocks");
}
// Get the number of bytes to allocate from the FrameInfo
uint64_t StackSize = MFI->getStackSize();
unsigned CSSize = X86FI->getCalleeSavedFrameSize();
uint64_t NumBytes = StackSize - CSSize;
if (hasFP(MF)) {
// pop EBP.
BuildMI(MBB, MBBI, TII.get(Is64Bit ? X86::POP64r : X86::POP32r), FramePtr);
NumBytes -= SlotSize;
}
// Skip the callee-saved pop instructions.
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;
}
// 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! Also, if it's main() on Cygwin/Mingw32 we
// aligned stack in the prologue, - revert stack changes back. Note: we're
// assuming, that frame pointer was forced for main()
if (MFI->hasVarSizedObjects() ||
(Fn->hasExternalLinkage() && Fn->getName() == "main" &&
Subtarget->isTargetCygMing())) {
unsigned Opc = Is64Bit ? X86::LEA64r : X86::LEA32r;
if (CSSize) {
MachineInstr *MI = addRegOffset(BuildMI(TII.get(Opc), StackPtr),
FramePtr, -CSSize);
MBB.insert(MBBI, MI);
} else
BuildMI(MBB, MBBI, TII.get(Is64Bit ? X86::MOV64rr : X86::MOV32rr),StackPtr).
addReg(FramePtr);
NumBytes = 0;
}
// adjust stack pointer back: ESP += numbytes
if (NumBytes)
emitSPUpdate(MBB, MBBI, StackPtr, NumBytes, Is64Bit, TII);
// We're returning from function via eh_return.
if (RetOpcode == X86::EH_RETURN) {
MBBI = prior(MBB.end());
MachineOperand &DestAddr = MBBI->getOperand(0);
assert(DestAddr.isRegister() && "Offset should be in register!");
BuildMI(MBB, MBBI, TII.get(Is64Bit ? X86::MOV64rr : X86::MOV32rr),StackPtr).
addReg(DestAddr.getReg());
// Tail call return: adjust the stack pointer and jump to callee
} else if (RetOpcode == X86::TCRETURNri || RetOpcode == X86::TCRETURNdi ||
RetOpcode== X86::TCRETURNri64 || RetOpcode == X86::TCRETURNdi64) {
MBBI = prior(MBB.end());
MachineOperand &JumpTarget = MBBI->getOperand(0);
MachineOperand &StackAdjust = MBBI->getOperand(1);
assert( StackAdjust.isImmediate() && "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, TII.get(X86::TAILJMPd)).
addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset());
else if (RetOpcode== X86::TCRETURNri64) {
BuildMI(MBB, MBBI, TII.get(X86::TAILJMPr64), JumpTarget.getReg());
} else
BuildMI(MBB, MBBI, 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 {
if (Is64Bit)
return X86::RIP; // Should have dwarf #16
else
return X86::EIP; // Should have dwarf #8
}
unsigned X86RegisterInfo::getFrameRegister(MachineFunction &MF) const {
return hasFP(MF) ? FramePtr : StackPtr;
}
int
X86RegisterInfo::getFrameIndexOffset(MachineFunction &MF, int FI) const {
int Offset = MF.getFrameInfo()->getObjectOffset(FI) + SlotSize;
if (!hasFP(MF))
return Offset + MF.getFrameInfo()->getStackSize();
Offset += SlotSize; // Skip the saved EBP
// Skip the RETADDR move area
X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
int TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
if (TailCallReturnAddrDelta < 0) Offset -= TailCallReturnAddrDelta;
return Offset;
}
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 {
assert(0 && "What is the exception register");
return 0;
}
unsigned X86RegisterInfo::getEHHandlerRegister() const {
assert(0 && "What is the exception handler register");
return 0;
}
namespace llvm {
unsigned getX86SubSuperRegister(unsigned Reg, MVT::ValueType VT, bool High) {
switch (VT) {
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"
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