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d97f3a5ab084485fe4931b6e7d8fa40ae4caa3c1
llvm-6502/lib/Target/X86/X86RegisterInfo.cpp
Chad Rosier d97f3a5ab0 [x86 frame lowering] In 32-bit mode, use ESI as the base pointer. 
Previously, we were using EBX, but PIC requires the GOT to be in EBX before 
function calls via PLT GOT pointer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161066 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-31 18:29:21 +00:00

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//===-- X86RegisterInfo.cpp - X86 Register Information --------------------===//
//
// 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 "X86RegisterInfo.h"
#include "X86.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/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/Target/TargetFrameLowering.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/ErrorHandling.h"
#include "llvm/Support/CommandLine.h"
#define GET_REGINFO_TARGET_DESC
#include "X86GenRegisterInfo.inc"
using namespace llvm;
cl::opt<bool>
ForceStackAlign("force-align-stack",
cl::desc("Force align the stack to the minimum alignment"
" needed for the function."),
cl::init(false), cl::Hidden);
cl::opt<bool>
EnableBasePointer("x86-use-base-pointer", cl::Hidden, cl::init(true),
cl::desc("Enable use of a base pointer for complex stack frames"));
X86RegisterInfo::X86RegisterInfo(X86TargetMachine &tm,
const TargetInstrInfo &tii)
: X86GenRegisterInfo(tm.getSubtarget<X86Subtarget>().is64Bit()
? X86::RIP : X86::EIP,
X86_MC::getDwarfRegFlavour(tm.getTargetTriple(), false),
X86_MC::getDwarfRegFlavour(tm.getTargetTriple(), true)),
TM(tm), TII(tii) {
X86_MC::InitLLVM2SEHRegisterMapping(this);
// Cache some information.
const X86Subtarget *Subtarget = &TM.getSubtarget<X86Subtarget>();
Is64Bit = Subtarget->is64Bit();
IsWin64 = Subtarget->isTargetWin64();
if (Is64Bit) {
SlotSize = 8;
StackPtr = X86::RSP;
FramePtr = X86::RBP;
} else {
SlotSize = 4;
StackPtr = X86::ESP;
FramePtr = X86::EBP;
}
// Use a callee-saved register as the base pointer. These registers must
// not conflict with any ABI requirements. For example, in 32-bit mode PIC
// requires GOT in the EBX register before function calls via PLT GOT pointer.
BasePtr = Is64Bit ? X86::RBX : X86::ESI;
}
/// getCompactUnwindRegNum - This function maps the register to the number for
/// compact unwind encoding. Return -1 if the register isn't valid.
int X86RegisterInfo::getCompactUnwindRegNum(unsigned RegNum, bool isEH) const {
switch (getLLVMRegNum(RegNum, isEH)) {
case X86::EBX: case X86::RBX: return 1;
case X86::ECX: case X86::R12: return 2;
case X86::EDX: case X86::R13: return 3;
case X86::EDI: case X86::R14: return 4;
case X86::ESI: case X86::R15: return 5;
case X86::EBP: case X86::RBP: return 6;
}
return -1;
}
bool
X86RegisterInfo::trackLivenessAfterRegAlloc(const MachineFunction &MF) const {
// Only enable when post-RA scheduling is enabled and this is needed.
return TM.getSubtargetImpl()->postRAScheduler();
}
int
X86RegisterInfo::getSEHRegNum(unsigned i) const {
int reg = X86_MC::getX86RegNum(i);
switch (i) {
case X86::R8: case X86::R8D: case X86::R8W: case X86::R8B:
case X86::R9: case X86::R9D: case X86::R9W: case X86::R9B:
case X86::R10: case X86::R10D: case X86::R10W: case X86::R10B:
case X86::R11: case X86::R11D: case X86::R11W: case X86::R11B:
case X86::R12: case X86::R12D: case X86::R12W: case X86::R12B:
case X86::R13: case X86::R13D: case X86::R13W: case X86::R13B:
case X86::R14: case X86::R14D: case X86::R14W: case X86::R14B:
case X86::R15: case X86::R15D: case X86::R15W: case X86::R15B:
case X86::XMM8: case X86::XMM9: case X86::XMM10: case X86::XMM11:
case X86::XMM12: case X86::XMM13: case X86::XMM14: case X86::XMM15:
case X86::YMM8: case X86::YMM9: case X86::YMM10: case X86::YMM11:
case X86::YMM12: case X86::YMM13: case X86::YMM14: case X86::YMM15:
reg += 8;
}
return reg;
}
const TargetRegisterClass *
X86RegisterInfo::getSubClassWithSubReg(const TargetRegisterClass *RC,
unsigned Idx) const {
// The sub_8bit sub-register index is more constrained in 32-bit mode.
// It behaves just like the sub_8bit_hi index.
if (!Is64Bit && Idx == X86::sub_8bit)
Idx = X86::sub_8bit_hi;
// Forward to TableGen's default version.
return X86GenRegisterInfo::getSubClassWithSubReg(RC, Idx);
}
const TargetRegisterClass *
X86RegisterInfo::getMatchingSuperRegClass(const TargetRegisterClass *A,
const TargetRegisterClass *B,
unsigned SubIdx) const {
// The sub_8bit sub-register index is more constrained in 32-bit mode.
if (!Is64Bit && SubIdx == X86::sub_8bit) {
A = X86GenRegisterInfo::getSubClassWithSubReg(A, X86::sub_8bit_hi);
if (!A)
return 0;
}
return X86GenRegisterInfo::getMatchingSuperRegClass(A, B, SubIdx);
}
const TargetRegisterClass*
X86RegisterInfo::getLargestLegalSuperClass(const TargetRegisterClass *RC) const{
// Don't allow super-classes of GR8_NOREX. This class is only used after
// extrating sub_8bit_hi sub-registers. The H sub-registers cannot be copied
// to the full GR8 register class in 64-bit mode, so we cannot allow the
// reigster class inflation.
//
// The GR8_NOREX class is always used in a way that won't be constrained to a
// sub-class, so sub-classes like GR8_ABCD_L are allowed to expand to the
// full GR8 class.
if (RC == &X86::GR8_NOREXRegClass)
return RC;
const TargetRegisterClass *Super = RC;
TargetRegisterClass::sc_iterator I = RC->getSuperClasses();
do {
switch (Super->getID()) {
case X86::GR8RegClassID:
case X86::GR16RegClassID:
case X86::GR32RegClassID:
case X86::GR64RegClassID:
case X86::FR32RegClassID:
case X86::FR64RegClassID:
case X86::RFP32RegClassID:
case X86::RFP64RegClassID:
case X86::RFP80RegClassID:
case X86::VR128RegClassID:
case X86::VR256RegClassID:
// Don't return a super-class that would shrink the spill size.
// That can happen with the vector and float classes.
if (Super->getSize() == RC->getSize())
return Super;
}
Super = *I++;
} while (Super);
return RC;
}
const TargetRegisterClass *
X86RegisterInfo::getPointerRegClass(const MachineFunction &MF, 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 GPRs except the stack pointer (for encoding reasons).
if (TM.getSubtarget<X86Subtarget>().is64Bit())
return &X86::GR64_NOSPRegClass;
return &X86::GR32_NOSPRegClass;
case 2: // Available for tailcall (not callee-saved GPRs).
if (TM.getSubtarget<X86Subtarget>().isTargetWin64())
return &X86::GR64_TCW64RegClass;
if (TM.getSubtarget<X86Subtarget>().is64Bit())
return &X86::GR64_TCRegClass;
return &X86::GR32_TCRegClass;
}
}
const TargetRegisterClass *
X86RegisterInfo::getCrossCopyRegClass(const TargetRegisterClass *RC) const {
if (RC == &X86::CCRRegClass) {
if (Is64Bit)
return &X86::GR64RegClass;
else
return &X86::GR32RegClass;
}
return RC;
}
unsigned
X86RegisterInfo::getRegPressureLimit(const TargetRegisterClass *RC,
MachineFunction &MF) const {
const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
unsigned FPDiff = TFI->hasFP(MF) ? 1 : 0;
switch (RC->getID()) {
default:
return 0;
case X86::GR32RegClassID:
return 4 - FPDiff;
case X86::GR64RegClassID:
return 12 - FPDiff;
case X86::VR128RegClassID:
return TM.getSubtarget<X86Subtarget>().is64Bit() ? 10 : 4;
case X86::VR64RegClassID:
return 4;
}
}
const uint16_t *
X86RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
bool callsEHReturn = false;
bool ghcCall = false;
if (MF) {
callsEHReturn = MF->getMMI().callsEHReturn();
const Function *F = MF->getFunction();
ghcCall = (F ? F->getCallingConv() == CallingConv::GHC : false);
}
if (ghcCall)
return CSR_NoRegs_SaveList;
if (Is64Bit) {
if (IsWin64)
return CSR_Win64_SaveList;
if (callsEHReturn)
return CSR_64EHRet_SaveList;
return CSR_64_SaveList;
}
if (callsEHReturn)
return CSR_32EHRet_SaveList;
return CSR_32_SaveList;
}
const uint32_t*
X86RegisterInfo::getCallPreservedMask(CallingConv::ID CC) const {
if (CC == CallingConv::GHC)
return CSR_NoRegs_RegMask;
if (!Is64Bit)
return CSR_32_RegMask;
if (IsWin64)
return CSR_Win64_RegMask;
return CSR_64_RegMask;
}
BitVector X86RegisterInfo::getReservedRegs(const MachineFunction &MF) const {
BitVector Reserved(getNumRegs());
const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
// Set the stack-pointer register and its aliases as reserved.
Reserved.set(X86::RSP);
for (MCSubRegIterator I(X86::RSP, this); I.isValid(); ++I)
Reserved.set(*I);
// Set the instruction pointer register and its aliases as reserved.
Reserved.set(X86::RIP);
for (MCSubRegIterator I(X86::RIP, this); I.isValid(); ++I)
Reserved.set(*I);
// Set the frame-pointer register and its aliases as reserved if needed.
if (TFI->hasFP(MF)) {
Reserved.set(X86::RBP);
for (MCSubRegIterator I(X86::RBP, this); I.isValid(); ++I)
Reserved.set(*I);
}
// Set the base-pointer register and its aliases as reserved if needed.
if (hasBasePointer(MF)) {
CallingConv::ID CC = MF.getFunction()->getCallingConv();
const uint32_t* RegMask = getCallPreservedMask(CC);
if (MachineOperand::clobbersPhysReg(RegMask, getBaseRegister()))
report_fatal_error(
"Stack realignment in presence of dynamic allocas is not supported with"
"this calling convention.");
Reserved.set(getBaseRegister());
for (MCSubRegIterator I(getBaseRegister(), this); I.isValid(); ++I)
Reserved.set(*I);
}
// Mark the segment registers as reserved.
Reserved.set(X86::CS);
Reserved.set(X86::SS);
Reserved.set(X86::DS);
Reserved.set(X86::ES);
Reserved.set(X86::FS);
Reserved.set(X86::GS);
// Mark the floating point stack registers as reserved.
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);
// Reserve the registers that only exist in 64-bit mode.
if (!Is64Bit) {
// These 8-bit registers are part of the x86-64 extension even though their
// super-registers are old 32-bits.
Reserved.set(X86::SIL);
Reserved.set(X86::DIL);
Reserved.set(X86::BPL);
Reserved.set(X86::SPL);
for (unsigned n = 0; n != 8; ++n) {
// R8, R9, ...
static const uint16_t GPR64[] = {
X86::R8, X86::R9, X86::R10, X86::R11,
X86::R12, X86::R13, X86::R14, X86::R15
};
for (MCRegAliasIterator AI(GPR64[n], this, true); AI.isValid(); ++AI)
Reserved.set(*AI);
// XMM8, XMM9, ...
assert(X86::XMM15 == X86::XMM8+7);
for (MCRegAliasIterator AI(X86::XMM8 + n, this, true); AI.isValid(); ++AI)
Reserved.set(*AI);
}
}
return Reserved;
}
//===----------------------------------------------------------------------===//
// Stack Frame Processing methods
//===----------------------------------------------------------------------===//
bool X86RegisterInfo::hasBasePointer(const MachineFunction &MF) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
if (!EnableBasePointer)
return false;
// When we need stack realignment and there are dynamic allocas, we can't
// reference off of the stack pointer, so we reserve a base pointer.
if (needsStackRealignment(MF) && MFI->hasVarSizedObjects())
return true;
return false;
}
bool X86RegisterInfo::canRealignStack(const MachineFunction &MF) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
const MachineRegisterInfo *MRI = &MF.getRegInfo();
if (!MF.getTarget().Options.RealignStack)
return false;
// Stack realignment requires a frame pointer. If we already started
// register allocation with frame pointer elimination, it is too late now.
if (!MRI->canReserveReg(FramePtr))
return false;
// If a base pointer is necessary. Check that it isn't too late to reserve
// it.
if (MFI->hasVarSizedObjects())
return MRI->canReserveReg(BasePtr);
return true;
}
bool X86RegisterInfo::needsStackRealignment(const MachineFunction &MF) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
const Function *F = MF.getFunction();
unsigned StackAlign = TM.getFrameLowering()->getStackAlignment();
bool requiresRealignment = ((MFI->getMaxAlignment() > StackAlign) ||
F->hasFnAttr(Attribute::StackAlignment));
// If we've requested that we force align the stack do so now.
if (ForceStackAlign)
return canRealignStack(MF);
return requiresRealignment && canRealignStack(MF);
}
bool X86RegisterInfo::hasReservedSpillSlot(const MachineFunction &MF,
unsigned Reg, int &FrameIdx) const {
const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
if (Reg == FramePtr && TFI->hasFP(MF)) {
FrameIdx = MF.getFrameInfo()->getObjectIndexBegin();
return true;
}
return false;
}
static unsigned getSUBriOpcode(unsigned is64Bit, int64_t Imm) {
if (is64Bit) {
if (isInt<8>(Imm))
return X86::SUB64ri8;
return X86::SUB64ri32;
} else {
if (isInt<8>(Imm))
return X86::SUB32ri8;
return X86::SUB32ri;
}
}
static unsigned getADDriOpcode(unsigned is64Bit, int64_t Imm) {
if (is64Bit) {
if (isInt<8>(Imm))
return X86::ADD64ri8;
return X86::ADD64ri32;
} else {
if (isInt<8>(Imm))
return X86::ADD32ri8;
return X86::ADD32ri;
}
}
void X86RegisterInfo::
eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
bool reseveCallFrame = TFI->hasReservedCallFrame(MF);
int Opcode = I->getOpcode();
bool isDestroy = Opcode == TII.getCallFrameDestroyOpcode();
DebugLoc DL = I->getDebugLoc();
uint64_t Amount = !reseveCallFrame ? I->getOperand(0).getImm() : 0;
uint64_t CalleeAmt = isDestroy ? I->getOperand(1).getImm() : 0;
I = MBB.erase(I);
if (!reseveCallFrame) {
// 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
if (Amount == 0)
return;
// We need to keep the stack aligned properly. To do this, we round the
// amount of space needed for the outgoing arguments up to the next
// alignment boundary.
unsigned StackAlign = TM.getFrameLowering()->getStackAlignment();
Amount = (Amount + StackAlign - 1) / StackAlign * StackAlign;
MachineInstr *New = 0;
if (Opcode == TII.getCallFrameSetupOpcode()) {
New = BuildMI(MF, DL, TII.get(getSUBriOpcode(Is64Bit, Amount)),
StackPtr)
.addReg(StackPtr)
.addImm(Amount);
} else {
assert(Opcode == TII.getCallFrameDestroyOpcode());
// Factor out the amount the callee already popped.
Amount -= CalleeAmt;
if (Amount) {
unsigned Opc = getADDriOpcode(Is64Bit, Amount);
New = BuildMI(MF, DL, 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);
}
return;
}
if (Opcode == TII.getCallFrameDestroyOpcode() && CalleeAmt) {
// 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.
unsigned Opc = getSUBriOpcode(Is64Bit, CalleeAmt);
MachineInstr *New = BuildMI(MF, DL, TII.get(Opc), StackPtr)
.addReg(StackPtr).addImm(CalleeAmt);
// The EFLAGS implicit def is dead.
New->getOperand(3).setIsDead();
// We are not tracking the stack pointer adjustment by the callee, so make
// sure we restore the stack pointer immediately after the call, there may
// be spill code inserted between the CALL and ADJCALLSTACKUP instructions.
MachineBasicBlock::iterator B = MBB.begin();
while (I != B && !llvm::prior(I)->isCall())
--I;
MBB.insert(I, New);
}
}
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();
const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
while (!MI.getOperand(i).isFI()) {
++i;
assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
}
int FrameIndex = MI.getOperand(i).getIndex();
unsigned BasePtr;
unsigned Opc = MI.getOpcode();
bool AfterFPPop = Opc == X86::TAILJMPm64 || Opc == X86::TAILJMPm;
if (hasBasePointer(MF))
BasePtr = (FrameIndex < 0 ? FramePtr : getBaseRegister());
else if (needsStackRealignment(MF))
BasePtr = (FrameIndex < 0 ? FramePtr : StackPtr);
else if (AfterFPPop)
BasePtr = StackPtr;
else
BasePtr = (TFI->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.
int FIOffset;
if (AfterFPPop) {
// Tail call jmp happens after FP is popped.
const MachineFrameInfo *MFI = MF.getFrameInfo();
FIOffset = MFI->getObjectOffset(FrameIndex) - TFI->getOffsetOfLocalArea();
} else
FIOffset = TFI->getFrameIndexOffset(MF, FrameIndex);
if (MI.getOperand(i+3).isImm()) {
// Offset is a 32-bit integer.
int Imm = (int)(MI.getOperand(i + 3).getImm());
int Offset = FIOffset + Imm;
assert((!Is64Bit || isInt<32>((long long)FIOffset + Imm)) &&
"Requesting 64-bit offset in 32-bit immediate!");
MI.getOperand(i + 3).ChangeToImmediate(Offset);
} else {
// Offset is symbolic. This is extremely rare.
uint64_t Offset = FIOffset + (uint64_t)MI.getOperand(i+3).getOffset();
MI.getOperand(i+3).setOffset(Offset);
}
}
unsigned X86RegisterInfo::getFrameRegister(const MachineFunction &MF) const {
const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
return TFI->hasFP(MF) ? FramePtr : StackPtr;
}
unsigned X86RegisterInfo::getEHExceptionRegister() const {
llvm_unreachable("What is the exception register");
}
unsigned X86RegisterInfo::getEHHandlerRegister() const {
llvm_unreachable("What is the exception handler register");
}
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 getX86SubSuperRegister(Reg, MVT::i64, High);
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:
// For 64-bit mode if we've requested a "high" register and the
// Q or r constraints we want one of these high registers or
// just the register name otherwise.
if (High) {
switch (Reg) {
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;
// Fallthrough.
}
}
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;
}
}
}
}
namespace {
struct MSAH : public MachineFunctionPass {
static char ID;
MSAH() : MachineFunctionPass(ID) {}
virtual bool runOnMachineFunction(MachineFunction &MF) {
const X86TargetMachine *TM =
static_cast<const X86TargetMachine *>(&MF.getTarget());
const TargetFrameLowering *TFI = TM->getFrameLowering();
MachineRegisterInfo &RI = MF.getRegInfo();
X86MachineFunctionInfo *FuncInfo = MF.getInfo<X86MachineFunctionInfo>();
unsigned StackAlignment = TFI->getStackAlignment();
// Be over-conservative: scan over all vreg defs and find whether vector
// registers are used. If yes, there is a possibility that vector register
// will be spilled and thus require dynamic stack realignment.
for (unsigned i = 0, e = RI.getNumVirtRegs(); i != e; ++i) {
unsigned Reg = TargetRegisterInfo::index2VirtReg(i);
if (RI.getRegClass(Reg)->getAlignment() > StackAlignment) {
FuncInfo->setForceFramePointer(true);
return true;
}
}
// Nothing to do
return false;
}
virtual const char *getPassName() const {
return "X86 Maximal Stack Alignment Check";
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
MachineFunctionPass::getAnalysisUsage(AU);
}
};
char MSAH::ID = 0;
}
FunctionPass*
llvm::createX86MaxStackAlignmentHeuristicPass() { return new MSAH(); }
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