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llvm-6502/lib/Target/ARM/ARMBaseRegisterInfo.cpp
Jim Grosbach 803b48a155 Now that the default is 'enabled,' a separate command line option for ARM is 
not necessary.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86621 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-09 23:11:45 +00:00

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//===- ARMBaseRegisterInfo.cpp - ARM 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 base ARM implementation of TargetRegisterInfo class.
//
//===----------------------------------------------------------------------===//
#include "ARM.h"
#include "ARMAddressingModes.h"
#include "ARMBaseInstrInfo.h"
#include "ARMBaseRegisterInfo.h"
#include "ARMInstrInfo.h"
#include "ARMMachineFunctionInfo.h"
#include "ARMSubtarget.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/LLVMContext.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineLocation.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/CommandLine.h"
using namespace llvm;
static cl::opt<bool>
ReuseFrameIndexVals("arm-reuse-frame-index-vals", cl::Hidden, cl::init(true),
cl::desc("Reuse repeated frame index values"));
unsigned ARMBaseRegisterInfo::getRegisterNumbering(unsigned RegEnum,
bool *isSPVFP) {
if (isSPVFP)
*isSPVFP = false;
using namespace ARM;
switch (RegEnum) {
default:
llvm_unreachable("Unknown ARM register!");
case R0: case D0: case Q0: return 0;
case R1: case D1: case Q1: return 1;
case R2: case D2: case Q2: return 2;
case R3: case D3: case Q3: return 3;
case R4: case D4: case Q4: return 4;
case R5: case D5: case Q5: return 5;
case R6: case D6: case Q6: return 6;
case R7: case D7: case Q7: return 7;
case R8: case D8: case Q8: return 8;
case R9: case D9: case Q9: return 9;
case R10: case D10: case Q10: return 10;
case R11: case D11: case Q11: return 11;
case R12: case D12: case Q12: return 12;
case SP: case D13: case Q13: return 13;
case LR: case D14: case Q14: return 14;
case PC: case D15: case Q15: return 15;
case D16: return 16;
case D17: return 17;
case D18: return 18;
case D19: return 19;
case D20: return 20;
case D21: return 21;
case D22: return 22;
case D23: return 23;
case D24: return 24;
case D25: return 25;
case D26: return 27;
case D27: return 27;
case D28: return 28;
case D29: return 29;
case D30: return 30;
case D31: return 31;
case S0: case S1: case S2: case S3:
case S4: case S5: case S6: case S7:
case S8: case S9: case S10: case S11:
case S12: case S13: case S14: case S15:
case S16: case S17: case S18: case S19:
case S20: case S21: case S22: case S23:
case S24: case S25: case S26: case S27:
case S28: case S29: case S30: case S31: {
if (isSPVFP)
*isSPVFP = true;
switch (RegEnum) {
default: return 0; // Avoid compile time warning.
case S0: return 0;
case S1: return 1;
case S2: return 2;
case S3: return 3;
case S4: return 4;
case S5: return 5;
case S6: return 6;
case S7: return 7;
case S8: return 8;
case S9: return 9;
case S10: return 10;
case S11: return 11;
case S12: return 12;
case S13: return 13;
case S14: return 14;
case S15: return 15;
case S16: return 16;
case S17: return 17;
case S18: return 18;
case S19: return 19;
case S20: return 20;
case S21: return 21;
case S22: return 22;
case S23: return 23;
case S24: return 24;
case S25: return 25;
case S26: return 26;
case S27: return 27;
case S28: return 28;
case S29: return 29;
case S30: return 30;
case S31: return 31;
}
}
}
}
ARMBaseRegisterInfo::ARMBaseRegisterInfo(const ARMBaseInstrInfo &tii,
const ARMSubtarget &sti)
: ARMGenRegisterInfo(ARM::ADJCALLSTACKDOWN, ARM::ADJCALLSTACKUP),
TII(tii), STI(sti),
FramePtr((STI.isTargetDarwin() || STI.isThumb()) ? ARM::R7 : ARM::R11) {
}
const unsigned*
ARMBaseRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
static const unsigned CalleeSavedRegs[] = {
ARM::LR, ARM::R11, ARM::R10, ARM::R9, ARM::R8,
ARM::R7, ARM::R6, ARM::R5, ARM::R4,
ARM::D15, ARM::D14, ARM::D13, ARM::D12,
ARM::D11, ARM::D10, ARM::D9, ARM::D8,
0
};
static const unsigned DarwinCalleeSavedRegs[] = {
// Darwin ABI deviates from ARM standard ABI. R9 is not a callee-saved
// register.
ARM::LR, ARM::R7, ARM::R6, ARM::R5, ARM::R4,
ARM::R11, ARM::R10, ARM::R8,
ARM::D15, ARM::D14, ARM::D13, ARM::D12,
ARM::D11, ARM::D10, ARM::D9, ARM::D8,
0
};
return STI.isTargetDarwin() ? DarwinCalleeSavedRegs : CalleeSavedRegs;
}
const TargetRegisterClass* const *
ARMBaseRegisterInfo::getCalleeSavedRegClasses(const MachineFunction *MF) const {
static const TargetRegisterClass * const CalleeSavedRegClasses[] = {
&ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
&ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
&ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
&ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
&ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
0
};
static const TargetRegisterClass * const ThumbCalleeSavedRegClasses[] = {
&ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
&ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::tGPRRegClass,
&ARM::tGPRRegClass,&ARM::tGPRRegClass,&ARM::tGPRRegClass,
&ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
&ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
0
};
static const TargetRegisterClass * const DarwinCalleeSavedRegClasses[] = {
&ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
&ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass,
&ARM::GPRRegClass, &ARM::GPRRegClass,
&ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
&ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
0
};
static const TargetRegisterClass * const DarwinThumbCalleeSavedRegClasses[] ={
&ARM::GPRRegClass, &ARM::tGPRRegClass, &ARM::tGPRRegClass,
&ARM::tGPRRegClass, &ARM::tGPRRegClass, &ARM::GPRRegClass,
&ARM::GPRRegClass, &ARM::GPRRegClass,
&ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
&ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass,
0
};
if (STI.isThumb1Only()) {
return STI.isTargetDarwin()
? DarwinThumbCalleeSavedRegClasses : ThumbCalleeSavedRegClasses;
}
return STI.isTargetDarwin()
? DarwinCalleeSavedRegClasses : CalleeSavedRegClasses;
}
BitVector ARMBaseRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
// FIXME: avoid re-calculating this everytime.
BitVector Reserved(getNumRegs());
Reserved.set(ARM::SP);
Reserved.set(ARM::PC);
if (STI.isTargetDarwin() || hasFP(MF))
Reserved.set(FramePtr);
// Some targets reserve R9.
if (STI.isR9Reserved())
Reserved.set(ARM::R9);
return Reserved;
}
bool ARMBaseRegisterInfo::isReservedReg(const MachineFunction &MF,
unsigned Reg) const {
switch (Reg) {
default: break;
case ARM::SP:
case ARM::PC:
return true;
case ARM::R7:
case ARM::R11:
if (FramePtr == Reg && (STI.isTargetDarwin() || hasFP(MF)))
return true;
break;
case ARM::R9:
return STI.isR9Reserved();
}
return false;
}
const TargetRegisterClass *
ARMBaseRegisterInfo::getMatchingSuperRegClass(const TargetRegisterClass *A,
const TargetRegisterClass *B,
unsigned SubIdx) const {
switch (SubIdx) {
default: return 0;
case 1:
case 2:
case 3:
case 4:
// S sub-registers.
if (A->getSize() == 8) {
if (B == &ARM::SPR_8RegClass)
return &ARM::DPR_8RegClass;
assert(B == &ARM::SPRRegClass && "Expecting SPR register class!");
if (A == &ARM::DPR_8RegClass)
return A;
return &ARM::DPR_VFP2RegClass;
}
assert(A->getSize() == 16 && "Expecting a Q register class!");
if (B == &ARM::SPR_8RegClass)
return &ARM::QPR_8RegClass;
return &ARM::QPR_VFP2RegClass;
case 5:
case 6:
// D sub-registers.
if (B == &ARM::DPR_VFP2RegClass)
return &ARM::QPR_VFP2RegClass;
if (B == &ARM::DPR_8RegClass)
return &ARM::QPR_8RegClass;
return A;
}
return 0;
}
const TargetRegisterClass *
ARMBaseRegisterInfo::getPointerRegClass(unsigned Kind) const {
return ARM::GPRRegisterClass;
}
/// getAllocationOrder - Returns the register allocation order for a specified
/// register class in the form of a pair of TargetRegisterClass iterators.
std::pair<TargetRegisterClass::iterator,TargetRegisterClass::iterator>
ARMBaseRegisterInfo::getAllocationOrder(const TargetRegisterClass *RC,
unsigned HintType, unsigned HintReg,
const MachineFunction &MF) const {
// Alternative register allocation orders when favoring even / odd registers
// of register pairs.
// No FP, R9 is available.
static const unsigned GPREven1[] = {
ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R8, ARM::R10,
ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R7,
ARM::R9, ARM::R11
};
static const unsigned GPROdd1[] = {
ARM::R1, ARM::R3, ARM::R5, ARM::R7, ARM::R9, ARM::R11,
ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6,
ARM::R8, ARM::R10
};
// FP is R7, R9 is available.
static const unsigned GPREven2[] = {
ARM::R0, ARM::R2, ARM::R4, ARM::R8, ARM::R10,
ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R6,
ARM::R9, ARM::R11
};
static const unsigned GPROdd2[] = {
ARM::R1, ARM::R3, ARM::R5, ARM::R9, ARM::R11,
ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6,
ARM::R8, ARM::R10
};
// FP is R11, R9 is available.
static const unsigned GPREven3[] = {
ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R8,
ARM::R1, ARM::R3, ARM::R10,ARM::R12,ARM::LR, ARM::R5, ARM::R7,
ARM::R9
};
static const unsigned GPROdd3[] = {
ARM::R1, ARM::R3, ARM::R5, ARM::R6, ARM::R9,
ARM::R0, ARM::R2, ARM::R10,ARM::R12,ARM::LR, ARM::R4, ARM::R7,
ARM::R8
};
// No FP, R9 is not available.
static const unsigned GPREven4[] = {
ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R10,
ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R7, ARM::R8,
ARM::R11
};
static const unsigned GPROdd4[] = {
ARM::R1, ARM::R3, ARM::R5, ARM::R7, ARM::R11,
ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8,
ARM::R10
};
// FP is R7, R9 is not available.
static const unsigned GPREven5[] = {
ARM::R0, ARM::R2, ARM::R4, ARM::R10,
ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R6, ARM::R8,
ARM::R11
};
static const unsigned GPROdd5[] = {
ARM::R1, ARM::R3, ARM::R5, ARM::R11,
ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8,
ARM::R10
};
// FP is R11, R9 is not available.
static const unsigned GPREven6[] = {
ARM::R0, ARM::R2, ARM::R4, ARM::R6,
ARM::R1, ARM::R3, ARM::R10,ARM::R12,ARM::LR, ARM::R5, ARM::R7, ARM::R8
};
static const unsigned GPROdd6[] = {
ARM::R1, ARM::R3, ARM::R5, ARM::R7,
ARM::R0, ARM::R2, ARM::R10,ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8
};
if (HintType == ARMRI::RegPairEven) {
if (isPhysicalRegister(HintReg) && getRegisterPairEven(HintReg, MF) == 0)
// It's no longer possible to fulfill this hint. Return the default
// allocation order.
return std::make_pair(RC->allocation_order_begin(MF),
RC->allocation_order_end(MF));
if (!STI.isTargetDarwin() && !hasFP(MF)) {
if (!STI.isR9Reserved())
return std::make_pair(GPREven1,
GPREven1 + (sizeof(GPREven1)/sizeof(unsigned)));
else
return std::make_pair(GPREven4,
GPREven4 + (sizeof(GPREven4)/sizeof(unsigned)));
} else if (FramePtr == ARM::R7) {
if (!STI.isR9Reserved())
return std::make_pair(GPREven2,
GPREven2 + (sizeof(GPREven2)/sizeof(unsigned)));
else
return std::make_pair(GPREven5,
GPREven5 + (sizeof(GPREven5)/sizeof(unsigned)));
} else { // FramePtr == ARM::R11
if (!STI.isR9Reserved())
return std::make_pair(GPREven3,
GPREven3 + (sizeof(GPREven3)/sizeof(unsigned)));
else
return std::make_pair(GPREven6,
GPREven6 + (sizeof(GPREven6)/sizeof(unsigned)));
}
} else if (HintType == ARMRI::RegPairOdd) {
if (isPhysicalRegister(HintReg) && getRegisterPairOdd(HintReg, MF) == 0)
// It's no longer possible to fulfill this hint. Return the default
// allocation order.
return std::make_pair(RC->allocation_order_begin(MF),
RC->allocation_order_end(MF));
if (!STI.isTargetDarwin() && !hasFP(MF)) {
if (!STI.isR9Reserved())
return std::make_pair(GPROdd1,
GPROdd1 + (sizeof(GPROdd1)/sizeof(unsigned)));
else
return std::make_pair(GPROdd4,
GPROdd4 + (sizeof(GPROdd4)/sizeof(unsigned)));
} else if (FramePtr == ARM::R7) {
if (!STI.isR9Reserved())
return std::make_pair(GPROdd2,
GPROdd2 + (sizeof(GPROdd2)/sizeof(unsigned)));
else
return std::make_pair(GPROdd5,
GPROdd5 + (sizeof(GPROdd5)/sizeof(unsigned)));
} else { // FramePtr == ARM::R11
if (!STI.isR9Reserved())
return std::make_pair(GPROdd3,
GPROdd3 + (sizeof(GPROdd3)/sizeof(unsigned)));
else
return std::make_pair(GPROdd6,
GPROdd6 + (sizeof(GPROdd6)/sizeof(unsigned)));
}
}
return std::make_pair(RC->allocation_order_begin(MF),
RC->allocation_order_end(MF));
}
/// ResolveRegAllocHint - Resolves the specified register allocation hint
/// to a physical register. Returns the physical register if it is successful.
unsigned
ARMBaseRegisterInfo::ResolveRegAllocHint(unsigned Type, unsigned Reg,
const MachineFunction &MF) const {
if (Reg == 0 || !isPhysicalRegister(Reg))
return 0;
if (Type == 0)
return Reg;
else if (Type == (unsigned)ARMRI::RegPairOdd)
// Odd register.
return getRegisterPairOdd(Reg, MF);
else if (Type == (unsigned)ARMRI::RegPairEven)
// Even register.
return getRegisterPairEven(Reg, MF);
return 0;
}
void
ARMBaseRegisterInfo::UpdateRegAllocHint(unsigned Reg, unsigned NewReg,
MachineFunction &MF) const {
MachineRegisterInfo *MRI = &MF.getRegInfo();
std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(Reg);
if ((Hint.first == (unsigned)ARMRI::RegPairOdd ||
Hint.first == (unsigned)ARMRI::RegPairEven) &&
Hint.second && TargetRegisterInfo::isVirtualRegister(Hint.second)) {
// If 'Reg' is one of the even / odd register pair and it's now changed
// (e.g. coalesced) into a different register. The other register of the
// pair allocation hint must be updated to reflect the relationship
// change.
unsigned OtherReg = Hint.second;
Hint = MRI->getRegAllocationHint(OtherReg);
if (Hint.second == Reg)
// Make sure the pair has not already divorced.
MRI->setRegAllocationHint(OtherReg, Hint.first, NewReg);
}
}
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 ARMBaseRegisterInfo::hasFP(const MachineFunction &MF) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
return (NoFramePointerElim ||
needsStackRealignment(MF) ||
MFI->hasVarSizedObjects() ||
MFI->isFrameAddressTaken());
}
bool ARMBaseRegisterInfo::
needsStackRealignment(const MachineFunction &MF) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
unsigned StackAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
return (RealignStack &&
!AFI->isThumb1OnlyFunction() &&
(MFI->getMaxAlignment() > StackAlign) &&
!MFI->hasVarSizedObjects());
}
bool ARMBaseRegisterInfo::cannotEliminateFrame(const MachineFunction &MF) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
if (NoFramePointerElim && MFI->hasCalls())
return true;
return MFI->hasVarSizedObjects() || MFI->isFrameAddressTaken()
|| needsStackRealignment(MF);
}
/// estimateStackSize - Estimate and return the size of the frame.
static unsigned estimateStackSize(MachineFunction &MF, MachineFrameInfo *MFI) {
const MachineFrameInfo *FFI = MF.getFrameInfo();
int Offset = 0;
for (int i = FFI->getObjectIndexBegin(); i != 0; ++i) {
int FixedOff = -FFI->getObjectOffset(i);
if (FixedOff > Offset) Offset = FixedOff;
}
for (unsigned i = 0, e = FFI->getObjectIndexEnd(); i != e; ++i) {
if (FFI->isDeadObjectIndex(i))
continue;
Offset += FFI->getObjectSize(i);
unsigned Align = FFI->getObjectAlignment(i);
// Adjust to alignment boundary
Offset = (Offset+Align-1)/Align*Align;
}
return (unsigned)Offset;
}
/// estimateRSStackSizeLimit - Look at each instruction that references stack
/// frames and return the stack size limit beyond which some of these
/// instructions will require scratch register during their expansion later.
unsigned
ARMBaseRegisterInfo::estimateRSStackSizeLimit(MachineFunction &MF) const {
unsigned Limit = (1 << 12) - 1;
for (MachineFunction::iterator BB = MF.begin(),E = MF.end(); BB != E; ++BB) {
for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end();
I != E; ++I) {
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
if (!I->getOperand(i).isFI()) continue;
const TargetInstrDesc &Desc = TII.get(I->getOpcode());
unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
if (AddrMode == ARMII::AddrMode3 ||
AddrMode == ARMII::AddrModeT2_i8)
return (1 << 8) - 1;
if (AddrMode == ARMII::AddrMode5 ||
AddrMode == ARMII::AddrModeT2_i8s4)
Limit = std::min(Limit, ((1U << 8) - 1) * 4);
if (AddrMode == ARMII::AddrModeT2_i12 && hasFP(MF))
// When the stack offset is negative, we will end up using
// the i8 instructions instead.
return (1 << 8) - 1;
break; // At most one FI per instruction
}
}
}
return Limit;
}
void
ARMBaseRegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
RegScavenger *RS) const {
// This tells PEI to spill the FP as if it is any other callee-save register
// to take advantage the eliminateFrameIndex machinery. This also ensures it
// is spilled in the order specified by getCalleeSavedRegs() to make it easier
// to combine multiple loads / stores.
bool CanEliminateFrame = true;
bool CS1Spilled = false;
bool LRSpilled = false;
unsigned NumGPRSpills = 0;
SmallVector<unsigned, 4> UnspilledCS1GPRs;
SmallVector<unsigned, 4> UnspilledCS2GPRs;
ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
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).
if (RealignStack) {
unsigned MaxAlign = std::max(MFI->getMaxAlignment(),
calculateMaxStackAlignment(MFI));
MFI->setMaxAlignment(MaxAlign);
}
// Don't spill FP if the frame can be eliminated. This is determined
// by scanning the callee-save registers to see if any is used.
const unsigned *CSRegs = getCalleeSavedRegs();
const TargetRegisterClass* const *CSRegClasses = getCalleeSavedRegClasses();
for (unsigned i = 0; CSRegs[i]; ++i) {
unsigned Reg = CSRegs[i];
bool Spilled = false;
if (MF.getRegInfo().isPhysRegUsed(Reg)) {
AFI->setCSRegisterIsSpilled(Reg);
Spilled = true;
CanEliminateFrame = false;
} else {
// Check alias registers too.
for (const unsigned *Aliases = getAliasSet(Reg); *Aliases; ++Aliases) {
if (MF.getRegInfo().isPhysRegUsed(*Aliases)) {
Spilled = true;
CanEliminateFrame = false;
}
}
}
if (CSRegClasses[i] == ARM::GPRRegisterClass ||
CSRegClasses[i] == ARM::tGPRRegisterClass) {
if (Spilled) {
NumGPRSpills++;
if (!STI.isTargetDarwin()) {
if (Reg == ARM::LR)
LRSpilled = true;
CS1Spilled = true;
continue;
}
// Keep track if LR and any of R4, R5, R6, and R7 is spilled.
switch (Reg) {
case ARM::LR:
LRSpilled = true;
// Fallthrough
case ARM::R4:
case ARM::R5:
case ARM::R6:
case ARM::R7:
CS1Spilled = true;
break;
default:
break;
}
} else {
if (!STI.isTargetDarwin()) {
UnspilledCS1GPRs.push_back(Reg);
continue;
}
switch (Reg) {
case ARM::R4:
case ARM::R5:
case ARM::R6:
case ARM::R7:
case ARM::LR:
UnspilledCS1GPRs.push_back(Reg);
break;
default:
UnspilledCS2GPRs.push_back(Reg);
break;
}
}
}
}
bool ForceLRSpill = false;
if (!LRSpilled && AFI->isThumb1OnlyFunction()) {
unsigned FnSize = TII.GetFunctionSizeInBytes(MF);
// Force LR to be spilled if the Thumb function size is > 2048. This enables
// use of BL to implement far jump. If it turns out that it's not needed
// then the branch fix up path will undo it.
if (FnSize >= (1 << 11)) {
CanEliminateFrame = false;
ForceLRSpill = true;
}
}
bool ExtraCSSpill = false;
if (!CanEliminateFrame || cannotEliminateFrame(MF)) {
AFI->setHasStackFrame(true);
// If LR is not spilled, but at least one of R4, R5, R6, and R7 is spilled.
// Spill LR as well so we can fold BX_RET to the registers restore (LDM).
if (!LRSpilled && CS1Spilled) {
MF.getRegInfo().setPhysRegUsed(ARM::LR);
AFI->setCSRegisterIsSpilled(ARM::LR);
NumGPRSpills++;
UnspilledCS1GPRs.erase(std::find(UnspilledCS1GPRs.begin(),
UnspilledCS1GPRs.end(), (unsigned)ARM::LR));
ForceLRSpill = false;
ExtraCSSpill = true;
}
// Darwin ABI requires FP to point to the stack slot that contains the
// previous FP.
if (STI.isTargetDarwin() || hasFP(MF)) {
MF.getRegInfo().setPhysRegUsed(FramePtr);
NumGPRSpills++;
}
// If stack and double are 8-byte aligned and we are spilling an odd number
// of GPRs. Spill one extra callee save GPR so we won't have to pad between
// the integer and double callee save areas.
unsigned TargetAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
if (TargetAlign == 8 && (NumGPRSpills & 1)) {
if (CS1Spilled && !UnspilledCS1GPRs.empty()) {
for (unsigned i = 0, e = UnspilledCS1GPRs.size(); i != e; ++i) {
unsigned Reg = UnspilledCS1GPRs[i];
// Don't spill high register if the function is thumb1
if (!AFI->isThumb1OnlyFunction() ||
isARMLowRegister(Reg) || Reg == ARM::LR) {
MF.getRegInfo().setPhysRegUsed(Reg);
AFI->setCSRegisterIsSpilled(Reg);
if (!isReservedReg(MF, Reg))
ExtraCSSpill = true;
break;
}
}
} else if (!UnspilledCS2GPRs.empty() &&
!AFI->isThumb1OnlyFunction()) {
unsigned Reg = UnspilledCS2GPRs.front();
MF.getRegInfo().setPhysRegUsed(Reg);
AFI->setCSRegisterIsSpilled(Reg);
if (!isReservedReg(MF, Reg))
ExtraCSSpill = true;
}
}
// Estimate if we might need to scavenge a register at some point in order
// to materialize a stack offset. If so, either spill one additional
// callee-saved register or reserve a special spill slot to facilitate
// register scavenging. Thumb1 needs a spill slot for stack pointer
// adjustments also, even when the frame itself is small.
if (RS && !ExtraCSSpill) {
MachineFrameInfo *MFI = MF.getFrameInfo();
// If any of the stack slot references may be out of range of an
// immediate offset, make sure a register (or a spill slot) is
// available for the register scavenger. Note that if we're indexing
// off the frame pointer, the effective stack size is 4 bytes larger
// since the FP points to the stack slot of the previous FP.
if (estimateStackSize(MF, MFI) + (hasFP(MF) ? 4 : 0)
>= estimateRSStackSizeLimit(MF)) {
// If any non-reserved CS register isn't spilled, just spill one or two
// extra. That should take care of it!
unsigned NumExtras = TargetAlign / 4;
SmallVector<unsigned, 2> Extras;
while (NumExtras && !UnspilledCS1GPRs.empty()) {
unsigned Reg = UnspilledCS1GPRs.back();
UnspilledCS1GPRs.pop_back();
if (!isReservedReg(MF, Reg)) {
Extras.push_back(Reg);
NumExtras--;
}
}
// For non-Thumb1 functions, also check for hi-reg CS registers
if (!AFI->isThumb1OnlyFunction()) {
while (NumExtras && !UnspilledCS2GPRs.empty()) {
unsigned Reg = UnspilledCS2GPRs.back();
UnspilledCS2GPRs.pop_back();
if (!isReservedReg(MF, Reg)) {
Extras.push_back(Reg);
NumExtras--;
}
}
}
if (Extras.size() && NumExtras == 0) {
for (unsigned i = 0, e = Extras.size(); i != e; ++i) {
MF.getRegInfo().setPhysRegUsed(Extras[i]);
AFI->setCSRegisterIsSpilled(Extras[i]);
}
} else if (!AFI->isThumb1OnlyFunction()) {
// note: Thumb1 functions spill to R12, not the stack.
// Reserve a slot closest to SP or frame pointer.
const TargetRegisterClass *RC = ARM::GPRRegisterClass;
RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
RC->getAlignment()));
}
}
}
}
if (ForceLRSpill) {
MF.getRegInfo().setPhysRegUsed(ARM::LR);
AFI->setCSRegisterIsSpilled(ARM::LR);
AFI->setLRIsSpilledForFarJump(true);
}
}
unsigned ARMBaseRegisterInfo::getRARegister() const {
return ARM::LR;
}
unsigned ARMBaseRegisterInfo::getFrameRegister(MachineFunction &MF) const {
if (STI.isTargetDarwin() || hasFP(MF))
return FramePtr;
return ARM::SP;
}
unsigned ARMBaseRegisterInfo::getEHExceptionRegister() const {
llvm_unreachable("What is the exception register");
return 0;
}
unsigned ARMBaseRegisterInfo::getEHHandlerRegister() const {
llvm_unreachable("What is the exception handler register");
return 0;
}
int ARMBaseRegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
return ARMGenRegisterInfo::getDwarfRegNumFull(RegNum, 0);
}
unsigned ARMBaseRegisterInfo::getRegisterPairEven(unsigned Reg,
const MachineFunction &MF) const {
switch (Reg) {
default: break;
// Return 0 if either register of the pair is a special register.
// So no R12, etc.
case ARM::R1:
return ARM::R0;
case ARM::R3:
return ARM::R2;
case ARM::R5:
return ARM::R4;
case ARM::R7:
return isReservedReg(MF, ARM::R7) ? 0 : ARM::R6;
case ARM::R9:
return isReservedReg(MF, ARM::R9) ? 0 :ARM::R8;
case ARM::R11:
return isReservedReg(MF, ARM::R11) ? 0 : ARM::R10;
case ARM::S1:
return ARM::S0;
case ARM::S3:
return ARM::S2;
case ARM::S5:
return ARM::S4;
case ARM::S7:
return ARM::S6;
case ARM::S9:
return ARM::S8;
case ARM::S11:
return ARM::S10;
case ARM::S13:
return ARM::S12;
case ARM::S15:
return ARM::S14;
case ARM::S17:
return ARM::S16;
case ARM::S19:
return ARM::S18;
case ARM::S21:
return ARM::S20;
case ARM::S23:
return ARM::S22;
case ARM::S25:
return ARM::S24;
case ARM::S27:
return ARM::S26;
case ARM::S29:
return ARM::S28;
case ARM::S31:
return ARM::S30;
case ARM::D1:
return ARM::D0;
case ARM::D3:
return ARM::D2;
case ARM::D5:
return ARM::D4;
case ARM::D7:
return ARM::D6;
case ARM::D9:
return ARM::D8;
case ARM::D11:
return ARM::D10;
case ARM::D13:
return ARM::D12;
case ARM::D15:
return ARM::D14;
case ARM::D17:
return ARM::D16;
case ARM::D19:
return ARM::D18;
case ARM::D21:
return ARM::D20;
case ARM::D23:
return ARM::D22;
case ARM::D25:
return ARM::D24;
case ARM::D27:
return ARM::D26;
case ARM::D29:
return ARM::D28;
case ARM::D31:
return ARM::D30;
}
return 0;
}
unsigned ARMBaseRegisterInfo::getRegisterPairOdd(unsigned Reg,
const MachineFunction &MF) const {
switch (Reg) {
default: break;
// Return 0 if either register of the pair is a special register.
// So no R12, etc.
case ARM::R0:
return ARM::R1;
case ARM::R2:
return ARM::R3;
case ARM::R4:
return ARM::R5;
case ARM::R6:
return isReservedReg(MF, ARM::R7) ? 0 : ARM::R7;
case ARM::R8:
return isReservedReg(MF, ARM::R9) ? 0 :ARM::R9;
case ARM::R10:
return isReservedReg(MF, ARM::R11) ? 0 : ARM::R11;
case ARM::S0:
return ARM::S1;
case ARM::S2:
return ARM::S3;
case ARM::S4:
return ARM::S5;
case ARM::S6:
return ARM::S7;
case ARM::S8:
return ARM::S9;
case ARM::S10:
return ARM::S11;
case ARM::S12:
return ARM::S13;
case ARM::S14:
return ARM::S15;
case ARM::S16:
return ARM::S17;
case ARM::S18:
return ARM::S19;
case ARM::S20:
return ARM::S21;
case ARM::S22:
return ARM::S23;
case ARM::S24:
return ARM::S25;
case ARM::S26:
return ARM::S27;
case ARM::S28:
return ARM::S29;
case ARM::S30:
return ARM::S31;
case ARM::D0:
return ARM::D1;
case ARM::D2:
return ARM::D3;
case ARM::D4:
return ARM::D5;
case ARM::D6:
return ARM::D7;
case ARM::D8:
return ARM::D9;
case ARM::D10:
return ARM::D11;
case ARM::D12:
return ARM::D13;
case ARM::D14:
return ARM::D15;
case ARM::D16:
return ARM::D17;
case ARM::D18:
return ARM::D19;
case ARM::D20:
return ARM::D21;
case ARM::D22:
return ARM::D23;
case ARM::D24:
return ARM::D25;
case ARM::D26:
return ARM::D27;
case ARM::D28:
return ARM::D29;
case ARM::D30:
return ARM::D31;
}
return 0;
}
/// emitLoadConstPool - Emits a load from constpool to materialize the
/// specified immediate.
void ARMBaseRegisterInfo::
emitLoadConstPool(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI,
DebugLoc dl,
unsigned DestReg, unsigned SubIdx, int Val,
ARMCC::CondCodes Pred,
unsigned PredReg) const {
MachineFunction &MF = *MBB.getParent();
MachineConstantPool *ConstantPool = MF.getConstantPool();
Constant *C =
ConstantInt::get(Type::getInt32Ty(MF.getFunction()->getContext()), Val);
unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
BuildMI(MBB, MBBI, dl, TII.get(ARM::LDRcp))
.addReg(DestReg, getDefRegState(true), SubIdx)
.addConstantPoolIndex(Idx)
.addReg(0).addImm(0).addImm(Pred).addReg(PredReg);
}
bool ARMBaseRegisterInfo::
requiresRegisterScavenging(const MachineFunction &MF) const {
return true;
}
bool ARMBaseRegisterInfo::
requiresFrameIndexScavenging(const MachineFunction &MF) const {
return true;
}
// hasReservedCallFrame - Under normal circumstances, when a frame pointer is
// not required, we reserve argument space for call sites in the function
// immediately on entry to the current function. This eliminates the need for
// add/sub sp brackets around call sites. Returns true if the call frame is
// included as part of the stack frame.
bool ARMBaseRegisterInfo::
hasReservedCallFrame(MachineFunction &MF) const {
const MachineFrameInfo *FFI = MF.getFrameInfo();
unsigned CFSize = FFI->getMaxCallFrameSize();
// It's not always a good idea to include the call frame as part of the
// stack frame. ARM (especially Thumb) has small immediate offset to
// address the stack frame. So a large call frame can cause poor codegen
// and may even makes it impossible to scavenge a register.
if (CFSize >= ((1 << 12) - 1) / 2) // Half of imm12
return false;
return !MF.getFrameInfo()->hasVarSizedObjects();
}
static void
emitSPUpdate(bool isARM,
MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
DebugLoc dl, const ARMBaseInstrInfo &TII,
int NumBytes,
ARMCC::CondCodes Pred = ARMCC::AL, unsigned PredReg = 0) {
if (isARM)
emitARMRegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes,
Pred, PredReg, TII);
else
emitT2RegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes,
Pred, PredReg, TII);
}
void ARMBaseRegisterInfo::
eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
if (!hasReservedCallFrame(MF)) {
// If we have alloca, convert as follows:
// ADJCALLSTACKDOWN -> sub, sp, sp, amount
// ADJCALLSTACKUP -> add, sp, sp, amount
MachineInstr *Old = I;
DebugLoc dl = Old->getDebugLoc();
unsigned 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.
unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
Amount = (Amount+Align-1)/Align*Align;
ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
assert(!AFI->isThumb1OnlyFunction() &&
"This eliminateCallFramePseudoInstr does not suppor Thumb1!");
bool isARM = !AFI->isThumbFunction();
// Replace the pseudo instruction with a new instruction...
unsigned Opc = Old->getOpcode();
ARMCC::CondCodes Pred = (ARMCC::CondCodes)Old->getOperand(1).getImm();
// FIXME: Thumb2 version of ADJCALLSTACKUP and ADJCALLSTACKDOWN?
if (Opc == ARM::ADJCALLSTACKDOWN || Opc == ARM::tADJCALLSTACKDOWN) {
// Note: PredReg is operand 2 for ADJCALLSTACKDOWN.
unsigned PredReg = Old->getOperand(2).getReg();
emitSPUpdate(isARM, MBB, I, dl, TII, -Amount, Pred, PredReg);
} else {
// Note: PredReg is operand 3 for ADJCALLSTACKUP.
unsigned PredReg = Old->getOperand(3).getReg();
assert(Opc == ARM::ADJCALLSTACKUP || Opc == ARM::tADJCALLSTACKUP);
emitSPUpdate(isARM, MBB, I, dl, TII, Amount, Pred, PredReg);
}
}
}
MBB.erase(I);
}
unsigned
ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
int SPAdj, int *Value,
RegScavenger *RS) const {
unsigned i = 0;
MachineInstr &MI = *II;
MachineBasicBlock &MBB = *MI.getParent();
MachineFunction &MF = *MBB.getParent();
const MachineFrameInfo *MFI = MF.getFrameInfo();
ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
assert(!AFI->isThumb1OnlyFunction() &&
"This eliminateFrameIndex does not support Thumb1!");
while (!MI.getOperand(i).isFI()) {
++i;
assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
}
unsigned FrameReg = ARM::SP;
int FrameIndex = MI.getOperand(i).getIndex();
int Offset = MFI->getObjectOffset(FrameIndex) + MFI->getStackSize() + SPAdj;
bool isFixed = MFI->isFixedObjectIndex(FrameIndex);
// When doing dynamic stack realignment, all of these need to change(?)
if (AFI->isGPRCalleeSavedArea1Frame(FrameIndex))
Offset -= AFI->getGPRCalleeSavedArea1Offset();
else if (AFI->isGPRCalleeSavedArea2Frame(FrameIndex))
Offset -= AFI->getGPRCalleeSavedArea2Offset();
else if (AFI->isDPRCalleeSavedAreaFrame(FrameIndex))
Offset -= AFI->getDPRCalleeSavedAreaOffset();
else if (needsStackRealignment(MF)) {
// When dynamically realigning the stack, use the frame pointer for
// parameters, and the stack pointer for locals.
assert (hasFP(MF) && "dynamic stack realignment without a FP!");
if (isFixed) {
FrameReg = getFrameRegister(MF);
Offset -= AFI->getFramePtrSpillOffset();
// When referencing from the frame pointer, stack pointer adjustments
// don't matter.
SPAdj = 0;
}
} else if (hasFP(MF) && AFI->hasStackFrame()) {
assert(SPAdj == 0 && "Unexpected stack offset!");
if (isFixed || MFI->hasVarSizedObjects()) {
// Use frame pointer to reference fixed objects unless this is a
// frameless function.
FrameReg = getFrameRegister(MF);
Offset -= AFI->getFramePtrSpillOffset();
} else if (AFI->isThumb2Function()) {
// In Thumb2 mode, the negative offset is very limited.
int FPOffset = Offset - AFI->getFramePtrSpillOffset();
if (FPOffset >= -255 && FPOffset < 0) {
FrameReg = getFrameRegister(MF);
Offset = FPOffset;
}
}
}
// Modify MI as necessary to handle as much of 'Offset' as possible
bool Done = false;
if (!AFI->isThumbFunction())
Done = rewriteARMFrameIndex(MI, i, FrameReg, Offset, TII);
else {
assert(AFI->isThumb2Function());
Done = rewriteT2FrameIndex(MI, i, FrameReg, Offset, TII);
}
if (Done)
return 0;
// If we get here, the immediate doesn't fit into the instruction. We folded
// as much as possible above, handle the rest, providing a register that is
// SP+LargeImm.
assert((Offset ||
(MI.getDesc().TSFlags & ARMII::AddrModeMask) == ARMII::AddrMode4) &&
"This code isn't needed if offset already handled!");
unsigned ScratchReg = 0;
int PIdx = MI.findFirstPredOperandIdx();
ARMCC::CondCodes Pred = (PIdx == -1)
? ARMCC::AL : (ARMCC::CondCodes)MI.getOperand(PIdx).getImm();
unsigned PredReg = (PIdx == -1) ? 0 : MI.getOperand(PIdx+1).getReg();
if (Offset == 0)
// Must be addrmode4.
MI.getOperand(i).ChangeToRegister(FrameReg, false, false, false);
else {
ScratchReg = MF.getRegInfo().createVirtualRegister(ARM::GPRRegisterClass);
if (Value) *Value = Offset;
if (!AFI->isThumbFunction())
emitARMRegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
Offset, Pred, PredReg, TII);
else {
assert(AFI->isThumb2Function());
emitT2RegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
Offset, Pred, PredReg, TII);
}
MI.getOperand(i).ChangeToRegister(ScratchReg, false, false, true);
if (!ReuseFrameIndexVals)
ScratchReg = 0;
}
return ScratchReg;
}
/// Move iterator past the next bunch of callee save load / store ops for
/// the particular spill area (1: integer area 1, 2: integer area 2,
/// 3: fp area, 0: don't care).
static void movePastCSLoadStoreOps(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI,
int Opc1, int Opc2, unsigned Area,
const ARMSubtarget &STI) {
while (MBBI != MBB.end() &&
((MBBI->getOpcode() == Opc1) || (MBBI->getOpcode() == Opc2)) &&
MBBI->getOperand(1).isFI()) {
if (Area != 0) {
bool Done = false;
unsigned Category = 0;
switch (MBBI->getOperand(0).getReg()) {
case ARM::R4: case ARM::R5: case ARM::R6: case ARM::R7:
case ARM::LR:
Category = 1;
break;
case ARM::R8: case ARM::R9: case ARM::R10: case ARM::R11:
Category = STI.isTargetDarwin() ? 2 : 1;
break;
case ARM::D8: case ARM::D9: case ARM::D10: case ARM::D11:
case ARM::D12: case ARM::D13: case ARM::D14: case ARM::D15:
Category = 3;
break;
default:
Done = true;
break;
}
if (Done || Category != Area)
break;
}
++MBBI;
}
}
void ARMBaseRegisterInfo::
emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front();
MachineBasicBlock::iterator MBBI = MBB.begin();
MachineFrameInfo *MFI = MF.getFrameInfo();
ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
assert(!AFI->isThumb1OnlyFunction() &&
"This emitPrologue does not suppor Thumb1!");
bool isARM = !AFI->isThumbFunction();
unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
unsigned NumBytes = MFI->getStackSize();
const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
DebugLoc dl = (MBBI != MBB.end() ?
MBBI->getDebugLoc() : DebugLoc::getUnknownLoc());
// Determine the sizes of each callee-save spill areas and record which frame
// belongs to which callee-save spill areas.
unsigned GPRCS1Size = 0, GPRCS2Size = 0, DPRCSSize = 0;
int FramePtrSpillFI = 0;
// Allocate the vararg register save area. This is not counted in NumBytes.
if (VARegSaveSize)
emitSPUpdate(isARM, MBB, MBBI, dl, TII, -VARegSaveSize);
if (!AFI->hasStackFrame()) {
if (NumBytes != 0)
emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes);
return;
}
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
unsigned Reg = CSI[i].getReg();
int FI = CSI[i].getFrameIdx();
switch (Reg) {
case ARM::R4:
case ARM::R5:
case ARM::R6:
case ARM::R7:
case ARM::LR:
if (Reg == FramePtr)
FramePtrSpillFI = FI;
AFI->addGPRCalleeSavedArea1Frame(FI);
GPRCS1Size += 4;
break;
case ARM::R8:
case ARM::R9:
case ARM::R10:
case ARM::R11:
if (Reg == FramePtr)
FramePtrSpillFI = FI;
if (STI.isTargetDarwin()) {
AFI->addGPRCalleeSavedArea2Frame(FI);
GPRCS2Size += 4;
} else {
AFI->addGPRCalleeSavedArea1Frame(FI);
GPRCS1Size += 4;
}
break;
default:
AFI->addDPRCalleeSavedAreaFrame(FI);
DPRCSSize += 8;
}
}
// Build the new SUBri to adjust SP for integer callee-save spill area 1.
emitSPUpdate(isARM, MBB, MBBI, dl, TII, -GPRCS1Size);
movePastCSLoadStoreOps(MBB, MBBI, ARM::STR, ARM::t2STRi12, 1, STI);
// Set FP to point to the stack slot that contains the previous FP.
// For Darwin, FP is R7, which has now been stored in spill area 1.
// Otherwise, if this is not Darwin, all the callee-saved registers go
// into spill area 1, including the FP in R11. In either case, it is
// now safe to emit this assignment.
if (STI.isTargetDarwin() || hasFP(MF)) {
unsigned ADDriOpc = !AFI->isThumbFunction() ? ARM::ADDri : ARM::t2ADDri;
MachineInstrBuilder MIB =
BuildMI(MBB, MBBI, dl, TII.get(ADDriOpc), FramePtr)
.addFrameIndex(FramePtrSpillFI).addImm(0);
AddDefaultCC(AddDefaultPred(MIB));
}
// Build the new SUBri to adjust SP for integer callee-save spill area 2.
emitSPUpdate(isARM, MBB, MBBI, dl, TII, -GPRCS2Size);
// Build the new SUBri to adjust SP for FP callee-save spill area.
movePastCSLoadStoreOps(MBB, MBBI, ARM::STR, ARM::t2STRi12, 2, STI);
emitSPUpdate(isARM, MBB, MBBI, dl, TII, -DPRCSSize);
// Determine starting offsets of spill areas.
unsigned DPRCSOffset = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize);
unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize;
unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size;
AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) + NumBytes);
AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset);
AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset);
AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset);
movePastCSLoadStoreOps(MBB, MBBI, ARM::VSTRD, 0, 3, STI);
NumBytes = DPRCSOffset;
if (NumBytes) {
// Adjust SP after all the callee-save spills.
emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes);
}
if (STI.isTargetELF() && hasFP(MF)) {
MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() -
AFI->getFramePtrSpillOffset());
}
AFI->setGPRCalleeSavedArea1Size(GPRCS1Size);
AFI->setGPRCalleeSavedArea2Size(GPRCS2Size);
AFI->setDPRCalleeSavedAreaSize(DPRCSSize);
// If we need dynamic stack realignment, do it here.
if (needsStackRealignment(MF)) {
unsigned Opc;
unsigned MaxAlign = MFI->getMaxAlignment();
assert (!AFI->isThumb1OnlyFunction());
Opc = AFI->isThumbFunction() ? ARM::t2BICri : ARM::BICri;
AddDefaultCC(AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(Opc), ARM::SP)
.addReg(ARM::SP, RegState::Kill)
.addImm(MaxAlign-1)));
}
}
static bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) {
for (unsigned i = 0; CSRegs[i]; ++i)
if (Reg == CSRegs[i])
return true;
return false;
}
static bool isCSRestore(MachineInstr *MI,
const ARMBaseInstrInfo &TII,
const unsigned *CSRegs) {
return ((MI->getOpcode() == (int)ARM::VLDRD ||
MI->getOpcode() == (int)ARM::LDR ||
MI->getOpcode() == (int)ARM::t2LDRi12) &&
MI->getOperand(1).isFI() &&
isCalleeSavedRegister(MI->getOperand(0).getReg(), CSRegs));
}
void ARMBaseRegisterInfo::
emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const {
MachineBasicBlock::iterator MBBI = prior(MBB.end());
assert(MBBI->getDesc().isReturn() &&
"Can only insert epilog into returning blocks");
DebugLoc dl = MBBI->getDebugLoc();
MachineFrameInfo *MFI = MF.getFrameInfo();
ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
assert(!AFI->isThumb1OnlyFunction() &&
"This emitEpilogue does not suppor Thumb1!");
bool isARM = !AFI->isThumbFunction();
unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
int NumBytes = (int)MFI->getStackSize();
if (!AFI->hasStackFrame()) {
if (NumBytes != 0)
emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes);
} else {
// Unwind MBBI to point to first LDR / VLDRD.
const unsigned *CSRegs = getCalleeSavedRegs();
if (MBBI != MBB.begin()) {
do
--MBBI;
while (MBBI != MBB.begin() && isCSRestore(MBBI, TII, CSRegs));
if (!isCSRestore(MBBI, TII, CSRegs))
++MBBI;
}
// Move SP to start of FP callee save spill area.
NumBytes -= (AFI->getGPRCalleeSavedArea1Size() +
AFI->getGPRCalleeSavedArea2Size() +
AFI->getDPRCalleeSavedAreaSize());
// Darwin ABI requires FP to point to the stack slot that contains the
// previous FP.
bool HasFP = hasFP(MF);
if ((STI.isTargetDarwin() && NumBytes) || HasFP) {
NumBytes = AFI->getFramePtrSpillOffset() - NumBytes;
// Reset SP based on frame pointer only if the stack frame extends beyond
// frame pointer stack slot or target is ELF and the function has FP.
if (HasFP ||
AFI->getGPRCalleeSavedArea2Size() ||
AFI->getDPRCalleeSavedAreaSize() ||
AFI->getDPRCalleeSavedAreaOffset()) {
if (NumBytes) {
if (isARM)
emitARMRegPlusImmediate(MBB, MBBI, dl, ARM::SP, FramePtr, -NumBytes,
ARMCC::AL, 0, TII);
else
emitT2RegPlusImmediate(MBB, MBBI, dl, ARM::SP, FramePtr, -NumBytes,
ARMCC::AL, 0, TII);
} else {
// Thumb2 or ARM.
if (isARM)
BuildMI(MBB, MBBI, dl, TII.get(ARM::MOVr), ARM::SP)
.addReg(FramePtr)
.addImm((unsigned)ARMCC::AL).addReg(0).addReg(0);
else
BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVgpr2gpr), ARM::SP)
.addReg(FramePtr);
}
}
} else if (NumBytes)
emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes);
// Move SP to start of integer callee save spill area 2.
movePastCSLoadStoreOps(MBB, MBBI, ARM::VLDRD, 0, 3, STI);
emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getDPRCalleeSavedAreaSize());
// Move SP to start of integer callee save spill area 1.
movePastCSLoadStoreOps(MBB, MBBI, ARM::LDR, ARM::t2LDRi12, 2, STI);
emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getGPRCalleeSavedArea2Size());
// Move SP to SP upon entry to the function.
movePastCSLoadStoreOps(MBB, MBBI, ARM::LDR, ARM::t2LDRi12, 1, STI);
emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getGPRCalleeSavedArea1Size());
}
if (VARegSaveSize)
emitSPUpdate(isARM, MBB, MBBI, dl, TII, VARegSaveSize);
}
#include "ARMGenRegisterInfo.inc"
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