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llvm-6502/lib/Target/ARM/ARMInstrInfo.cpp
Dan Gohman 92dfe2001e Remove isReg, isImm, and isMBB, and change all their users to use 
isRegister, isImmediate, and isMachineBasicBlock, which are equivalent,
and more popular.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41958 91177308-0d34-0410-b5e6-96231b3b80d8
2007-09-14 20:33:02 +00:00

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//===- ARMInstrInfo.cpp - ARM Instruction Information -----------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the "Instituto Nokia de Tecnologia" and
// is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the ARM implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#include "ARMInstrInfo.h"
#include "ARM.h"
#include "ARMAddressingModes.h"
#include "ARMGenInstrInfo.inc"
#include "ARMMachineFunctionInfo.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/CodeGen/LiveVariables.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/Target/TargetAsmInfo.h"
#include "llvm/Support/CommandLine.h"
using namespace llvm;
static cl::opt<bool> EnableARM3Addr("enable-arm-3-addr-conv", cl::Hidden,
cl::desc("Enable ARM 2-addr to 3-addr conv"));
ARMInstrInfo::ARMInstrInfo(const ARMSubtarget &STI)
: TargetInstrInfo(ARMInsts, array_lengthof(ARMInsts)),
RI(*this, STI) {
}
const TargetRegisterClass *ARMInstrInfo::getPointerRegClass() const {
return &ARM::GPRRegClass;
}
/// Return true if the instruction is a register to register move and
/// leave the source and dest operands in the passed parameters.
///
bool ARMInstrInfo::isMoveInstr(const MachineInstr &MI,
unsigned &SrcReg, unsigned &DstReg) const {
MachineOpCode oc = MI.getOpcode();
switch (oc) {
default:
return false;
case ARM::FCPYS:
case ARM::FCPYD:
SrcReg = MI.getOperand(1).getReg();
DstReg = MI.getOperand(0).getReg();
return true;
case ARM::MOVr:
case ARM::tMOVr:
assert(MI.getInstrDescriptor()->numOperands >= 2 &&
MI.getOperand(0).isRegister() &&
MI.getOperand(1).isRegister() &&
"Invalid ARM MOV instruction");
SrcReg = MI.getOperand(1).getReg();
DstReg = MI.getOperand(0).getReg();
return true;
}
}
unsigned ARMInstrInfo::isLoadFromStackSlot(MachineInstr *MI, int &FrameIndex) const{
switch (MI->getOpcode()) {
default: break;
case ARM::LDR:
if (MI->getOperand(1).isFrameIndex() &&
MI->getOperand(2).isRegister() &&
MI->getOperand(3).isImmediate() &&
MI->getOperand(2).getReg() == 0 &&
MI->getOperand(3).getImmedValue() == 0) {
FrameIndex = MI->getOperand(1).getFrameIndex();
return MI->getOperand(0).getReg();
}
break;
case ARM::FLDD:
case ARM::FLDS:
if (MI->getOperand(1).isFrameIndex() &&
MI->getOperand(2).isImmediate() &&
MI->getOperand(2).getImmedValue() == 0) {
FrameIndex = MI->getOperand(1).getFrameIndex();
return MI->getOperand(0).getReg();
}
break;
case ARM::tRestore:
if (MI->getOperand(1).isFrameIndex() &&
MI->getOperand(2).isImmediate() &&
MI->getOperand(2).getImmedValue() == 0) {
FrameIndex = MI->getOperand(1).getFrameIndex();
return MI->getOperand(0).getReg();
}
break;
}
return 0;
}
unsigned ARMInstrInfo::isStoreToStackSlot(MachineInstr *MI, int &FrameIndex) const {
switch (MI->getOpcode()) {
default: break;
case ARM::STR:
if (MI->getOperand(1).isFrameIndex() &&
MI->getOperand(2).isRegister() &&
MI->getOperand(3).isImmediate() &&
MI->getOperand(2).getReg() == 0 &&
MI->getOperand(3).getImmedValue() == 0) {
FrameIndex = MI->getOperand(1).getFrameIndex();
return MI->getOperand(0).getReg();
}
break;
case ARM::FSTD:
case ARM::FSTS:
if (MI->getOperand(1).isFrameIndex() &&
MI->getOperand(2).isImmediate() &&
MI->getOperand(2).getImmedValue() == 0) {
FrameIndex = MI->getOperand(1).getFrameIndex();
return MI->getOperand(0).getReg();
}
break;
case ARM::tSpill:
if (MI->getOperand(1).isFrameIndex() &&
MI->getOperand(2).isImmediate() &&
MI->getOperand(2).getImmedValue() == 0) {
FrameIndex = MI->getOperand(1).getFrameIndex();
return MI->getOperand(0).getReg();
}
break;
}
return 0;
}
static unsigned getUnindexedOpcode(unsigned Opc) {
switch (Opc) {
default: break;
case ARM::LDR_PRE:
case ARM::LDR_POST:
return ARM::LDR;
case ARM::LDRH_PRE:
case ARM::LDRH_POST:
return ARM::LDRH;
case ARM::LDRB_PRE:
case ARM::LDRB_POST:
return ARM::LDRB;
case ARM::LDRSH_PRE:
case ARM::LDRSH_POST:
return ARM::LDRSH;
case ARM::LDRSB_PRE:
case ARM::LDRSB_POST:
return ARM::LDRSB;
case ARM::STR_PRE:
case ARM::STR_POST:
return ARM::STR;
case ARM::STRH_PRE:
case ARM::STRH_POST:
return ARM::STRH;
case ARM::STRB_PRE:
case ARM::STRB_POST:
return ARM::STRB;
}
return 0;
}
MachineInstr *
ARMInstrInfo::convertToThreeAddress(MachineFunction::iterator &MFI,
MachineBasicBlock::iterator &MBBI,
LiveVariables &LV) const {
if (!EnableARM3Addr)
return NULL;
MachineInstr *MI = MBBI;
unsigned TSFlags = MI->getInstrDescriptor()->TSFlags;
bool isPre = false;
switch ((TSFlags & ARMII::IndexModeMask) >> ARMII::IndexModeShift) {
default: return NULL;
case ARMII::IndexModePre:
isPre = true;
break;
case ARMII::IndexModePost:
break;
}
// Try spliting an indexed load / store to a un-indexed one plus an add/sub
// operation.
unsigned MemOpc = getUnindexedOpcode(MI->getOpcode());
if (MemOpc == 0)
return NULL;
MachineInstr *UpdateMI = NULL;
MachineInstr *MemMI = NULL;
unsigned AddrMode = (TSFlags & ARMII::AddrModeMask);
const TargetInstrDescriptor *TID = MI->getInstrDescriptor();
unsigned NumOps = TID->numOperands;
bool isLoad = (TID->Flags & M_LOAD_FLAG) != 0;
const MachineOperand &WB = isLoad ? MI->getOperand(1) : MI->getOperand(0);
const MachineOperand &Base = MI->getOperand(2);
const MachineOperand &Offset = MI->getOperand(NumOps-3);
unsigned WBReg = WB.getReg();
unsigned BaseReg = Base.getReg();
unsigned OffReg = Offset.getReg();
unsigned OffImm = MI->getOperand(NumOps-2).getImm();
ARMCC::CondCodes Pred = (ARMCC::CondCodes)MI->getOperand(NumOps-1).getImm();
switch (AddrMode) {
default:
assert(false && "Unknown indexed op!");
return NULL;
case ARMII::AddrMode2: {
bool isSub = ARM_AM::getAM2Op(OffImm) == ARM_AM::sub;
unsigned Amt = ARM_AM::getAM2Offset(OffImm);
if (OffReg == 0) {
int SOImmVal = ARM_AM::getSOImmVal(Amt);
if (SOImmVal == -1)
// Can't encode it in a so_imm operand. This transformation will
// add more than 1 instruction. Abandon!
return NULL;
UpdateMI = BuildMI(get(isSub ? ARM::SUBri : ARM::ADDri), WBReg)
.addReg(BaseReg).addImm(SOImmVal)
.addImm(Pred).addReg(0).addReg(0);
} else if (Amt != 0) {
ARM_AM::ShiftOpc ShOpc = ARM_AM::getAM2ShiftOpc(OffImm);
unsigned SOOpc = ARM_AM::getSORegOpc(ShOpc, Amt);
UpdateMI = BuildMI(get(isSub ? ARM::SUBrs : ARM::ADDrs), WBReg)
.addReg(BaseReg).addReg(OffReg).addReg(0).addImm(SOOpc)
.addImm(Pred).addReg(0).addReg(0);
} else
UpdateMI = BuildMI(get(isSub ? ARM::SUBrr : ARM::ADDrr), WBReg)
.addReg(BaseReg).addReg(OffReg)
.addImm(Pred).addReg(0).addReg(0);
break;
}
case ARMII::AddrMode3 : {
bool isSub = ARM_AM::getAM3Op(OffImm) == ARM_AM::sub;
unsigned Amt = ARM_AM::getAM3Offset(OffImm);
if (OffReg == 0)
// Immediate is 8-bits. It's guaranteed to fit in a so_imm operand.
UpdateMI = BuildMI(get(isSub ? ARM::SUBri : ARM::ADDri), WBReg)
.addReg(BaseReg).addImm(Amt)
.addImm(Pred).addReg(0).addReg(0);
else
UpdateMI = BuildMI(get(isSub ? ARM::SUBrr : ARM::ADDrr), WBReg)
.addReg(BaseReg).addReg(OffReg)
.addImm(Pred).addReg(0).addReg(0);
break;
}
}
std::vector<MachineInstr*> NewMIs;
if (isPre) {
if (isLoad)
MemMI = BuildMI(get(MemOpc), MI->getOperand(0).getReg())
.addReg(WBReg).addReg(0).addImm(0).addImm(Pred);
else
MemMI = BuildMI(get(MemOpc)).addReg(MI->getOperand(1).getReg())
.addReg(WBReg).addReg(0).addImm(0).addImm(Pred);
NewMIs.push_back(MemMI);
NewMIs.push_back(UpdateMI);
} else {
if (isLoad)
MemMI = BuildMI(get(MemOpc), MI->getOperand(0).getReg())
.addReg(BaseReg).addReg(0).addImm(0).addImm(Pred);
else
MemMI = BuildMI(get(MemOpc)).addReg(MI->getOperand(1).getReg())
.addReg(BaseReg).addReg(0).addImm(0).addImm(Pred);
if (WB.isDead())
UpdateMI->getOperand(0).setIsDead();
NewMIs.push_back(UpdateMI);
NewMIs.push_back(MemMI);
}
// Transfer LiveVariables states, kill / dead info.
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
if (MO.isRegister() && MO.getReg() &&
MRegisterInfo::isVirtualRegister(MO.getReg())) {
unsigned Reg = MO.getReg();
LiveVariables::VarInfo &VI = LV.getVarInfo(Reg);
if (MO.isDef()) {
MachineInstr *NewMI = (Reg == WBReg) ? UpdateMI : MemMI;
if (MO.isDead())
LV.addVirtualRegisterDead(Reg, NewMI);
// Update the defining instruction.
if (VI.DefInst == MI)
VI.DefInst = NewMI;
}
if (MO.isUse() && MO.isKill()) {
for (unsigned j = 0; j < 2; ++j) {
// Look at the two new MI's in reverse order.
MachineInstr *NewMI = NewMIs[j];
int NIdx = NewMI->findRegisterUseOperandIdx(Reg);
if (NIdx == -1)
continue;
LV.addVirtualRegisterKilled(Reg, NewMI);
if (VI.removeKill(MI))
VI.Kills.push_back(NewMI);
break;
}
}
}
}
MFI->insert(MBBI, NewMIs[1]);
MFI->insert(MBBI, NewMIs[0]);
return NewMIs[0];
}
// Branch analysis.
bool ARMInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,MachineBasicBlock *&TBB,
MachineBasicBlock *&FBB,
std::vector<MachineOperand> &Cond) const {
// If the block has no terminators, it just falls into the block after it.
MachineBasicBlock::iterator I = MBB.end();
if (I == MBB.begin() || !isUnpredicatedTerminator(--I))
return false;
// Get the last instruction in the block.
MachineInstr *LastInst = I;
// If there is only one terminator instruction, process it.
unsigned LastOpc = LastInst->getOpcode();
if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) {
if (LastOpc == ARM::B || LastOpc == ARM::tB) {
TBB = LastInst->getOperand(0).getMachineBasicBlock();
return false;
}
if (LastOpc == ARM::Bcc || LastOpc == ARM::tBcc) {
// Block ends with fall-through condbranch.
TBB = LastInst->getOperand(0).getMachineBasicBlock();
Cond.push_back(LastInst->getOperand(1));
Cond.push_back(LastInst->getOperand(2));
return false;
}
return true; // Can't handle indirect branch.
}
// Get the instruction before it if it is a terminator.
MachineInstr *SecondLastInst = I;
// If there are three terminators, we don't know what sort of block this is.
if (SecondLastInst && I != MBB.begin() && isUnpredicatedTerminator(--I))
return true;
// If the block ends with ARM::B/ARM::tB and a ARM::Bcc/ARM::tBcc, handle it.
unsigned SecondLastOpc = SecondLastInst->getOpcode();
if ((SecondLastOpc == ARM::Bcc && LastOpc == ARM::B) ||
(SecondLastOpc == ARM::tBcc && LastOpc == ARM::tB)) {
TBB = SecondLastInst->getOperand(0).getMachineBasicBlock();
Cond.push_back(SecondLastInst->getOperand(1));
Cond.push_back(SecondLastInst->getOperand(2));
FBB = LastInst->getOperand(0).getMachineBasicBlock();
return false;
}
// If the block ends with two unconditional branches, handle it. The second
// one is not executed, so remove it.
if ((SecondLastOpc == ARM::B || SecondLastOpc==ARM::tB) &&
(LastOpc == ARM::B || LastOpc == ARM::tB)) {
TBB = SecondLastInst->getOperand(0).getMachineBasicBlock();
I = LastInst;
I->eraseFromParent();
return false;
}
// Likewise if it ends with a branch table followed by an unconditional branch.
// The branch folder can create these, and we must get rid of them for
// correctness of Thumb constant islands.
if ((SecondLastOpc == ARM::BR_JTr || SecondLastOpc==ARM::BR_JTm ||
SecondLastOpc == ARM::BR_JTadd || SecondLastOpc==ARM::tBR_JTr) &&
(LastOpc == ARM::B || LastOpc == ARM::tB)) {
I = LastInst;
I->eraseFromParent();
return true;
}
// Otherwise, can't handle this.
return true;
}
unsigned ARMInstrInfo::RemoveBranch(MachineBasicBlock &MBB) const {
MachineFunction &MF = *MBB.getParent();
ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
int BOpc = AFI->isThumbFunction() ? ARM::tB : ARM::B;
int BccOpc = AFI->isThumbFunction() ? ARM::tBcc : ARM::Bcc;
MachineBasicBlock::iterator I = MBB.end();
if (I == MBB.begin()) return 0;
--I;
if (I->getOpcode() != BOpc && I->getOpcode() != BccOpc)
return 0;
// Remove the branch.
I->eraseFromParent();
I = MBB.end();
if (I == MBB.begin()) return 1;
--I;
if (I->getOpcode() != BccOpc)
return 1;
// Remove the branch.
I->eraseFromParent();
return 2;
}
unsigned ARMInstrInfo::InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
MachineBasicBlock *FBB,
const std::vector<MachineOperand> &Cond) const {
MachineFunction &MF = *MBB.getParent();
ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
int BOpc = AFI->isThumbFunction() ? ARM::tB : ARM::B;
int BccOpc = AFI->isThumbFunction() ? ARM::tBcc : ARM::Bcc;
// Shouldn't be a fall through.
assert(TBB && "InsertBranch must not be told to insert a fallthrough");
assert((Cond.size() == 2 || Cond.size() == 0) &&
"ARM branch conditions have two components!");
if (FBB == 0) {
if (Cond.empty()) // Unconditional branch?
BuildMI(&MBB, get(BOpc)).addMBB(TBB);
else
BuildMI(&MBB, get(BccOpc)).addMBB(TBB)
.addImm(Cond[0].getImm()).addReg(Cond[1].getReg());
return 1;
}
// Two-way conditional branch.
BuildMI(&MBB, get(BccOpc)).addMBB(TBB)
.addImm(Cond[0].getImm()).addReg(Cond[1].getReg());
BuildMI(&MBB, get(BOpc)).addMBB(FBB);
return 2;
}
bool ARMInstrInfo::BlockHasNoFallThrough(MachineBasicBlock &MBB) const {
if (MBB.empty()) return false;
switch (MBB.back().getOpcode()) {
case ARM::BX_RET: // Return.
case ARM::LDM_RET:
case ARM::tBX_RET:
case ARM::tBX_RET_vararg:
case ARM::tPOP_RET:
case ARM::B:
case ARM::tB: // Uncond branch.
case ARM::tBR_JTr:
case ARM::BR_JTr: // Jumptable branch.
case ARM::BR_JTm: // Jumptable branch through mem.
case ARM::BR_JTadd: // Jumptable branch add to pc.
return true;
default: return false;
}
}
bool ARMInstrInfo::
ReverseBranchCondition(std::vector<MachineOperand> &Cond) const {
ARMCC::CondCodes CC = (ARMCC::CondCodes)(int)Cond[0].getImm();
Cond[0].setImm(ARMCC::getOppositeCondition(CC));
return false;
}
bool ARMInstrInfo::isPredicated(const MachineInstr *MI) const {
int PIdx = MI->findFirstPredOperandIdx();
return PIdx != -1 && MI->getOperand(PIdx).getImmedValue() != ARMCC::AL;
}
bool ARMInstrInfo::PredicateInstruction(MachineInstr *MI,
const std::vector<MachineOperand> &Pred) const {
unsigned Opc = MI->getOpcode();
if (Opc == ARM::B || Opc == ARM::tB) {
MI->setInstrDescriptor(get(Opc == ARM::B ? ARM::Bcc : ARM::tBcc));
MI->addImmOperand(Pred[0].getImmedValue());
MI->addRegOperand(Pred[1].getReg(), false);
return true;
}
int PIdx = MI->findFirstPredOperandIdx();
if (PIdx != -1) {
MachineOperand &PMO = MI->getOperand(PIdx);
PMO.setImm(Pred[0].getImmedValue());
MI->getOperand(PIdx+1).setReg(Pred[1].getReg());
return true;
}
return false;
}
bool
ARMInstrInfo::SubsumesPredicate(const std::vector<MachineOperand> &Pred1,
const std::vector<MachineOperand> &Pred2) const{
if (Pred1.size() > 2 || Pred2.size() > 2)
return false;
ARMCC::CondCodes CC1 = (ARMCC::CondCodes)Pred1[0].getImmedValue();
ARMCC::CondCodes CC2 = (ARMCC::CondCodes)Pred2[0].getImmedValue();
if (CC1 == CC2)
return true;
switch (CC1) {
default:
return false;
case ARMCC::AL:
return true;
case ARMCC::HS:
return CC2 == ARMCC::HI;
case ARMCC::LS:
return CC2 == ARMCC::LO || CC2 == ARMCC::EQ;
case ARMCC::GE:
return CC2 == ARMCC::GT;
case ARMCC::LE:
return CC2 == ARMCC::LT;
}
}
bool ARMInstrInfo::DefinesPredicate(MachineInstr *MI,
std::vector<MachineOperand> &Pred) const {
const TargetInstrDescriptor *TID = MI->getInstrDescriptor();
if (!TID->ImplicitDefs && (TID->Flags & M_HAS_OPTIONAL_DEF) == 0)
return false;
bool Found = false;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
if (MO.isRegister() && MO.getReg() == ARM::CPSR) {
Pred.push_back(MO);
Found = true;
}
}
return Found;
}
/// FIXME: Works around a gcc miscompilation with -fstrict-aliasing
static unsigned getNumJTEntries(const std::vector<MachineJumpTableEntry> &JT,
unsigned JTI) DISABLE_INLINE;
static unsigned getNumJTEntries(const std::vector<MachineJumpTableEntry> &JT,
unsigned JTI) {
return JT[JTI].MBBs.size();
}
/// GetInstSize - Return the size of the specified MachineInstr.
///
unsigned ARM::GetInstSize(MachineInstr *MI) {
MachineBasicBlock &MBB = *MI->getParent();
const MachineFunction *MF = MBB.getParent();
const TargetAsmInfo *TAI = MF->getTarget().getTargetAsmInfo();
// Basic size info comes from the TSFlags field.
const TargetInstrDescriptor *TID = MI->getInstrDescriptor();
unsigned TSFlags = TID->TSFlags;
switch ((TSFlags & ARMII::SizeMask) >> ARMII::SizeShift) {
default:
// If this machine instr is an inline asm, measure it.
if (MI->getOpcode() == ARM::INLINEASM)
return TAI->getInlineAsmLength(MI->getOperand(0).getSymbolName());
if (MI->getOpcode() == ARM::LABEL)
return 0;
assert(0 && "Unknown or unset size field for instr!");
break;
case ARMII::Size8Bytes: return 8; // Arm instruction x 2.
case ARMII::Size4Bytes: return 4; // Arm instruction.
case ARMII::Size2Bytes: return 2; // Thumb instruction.
case ARMII::SizeSpecial: {
switch (MI->getOpcode()) {
case ARM::CONSTPOOL_ENTRY:
// If this machine instr is a constant pool entry, its size is recorded as
// operand #2.
return MI->getOperand(2).getImm();
case ARM::BR_JTr:
case ARM::BR_JTm:
case ARM::BR_JTadd:
case ARM::tBR_JTr: {
// These are jumptable branches, i.e. a branch followed by an inlined
// jumptable. The size is 4 + 4 * number of entries.
unsigned NumOps = TID->numOperands;
MachineOperand JTOP =
MI->getOperand(NumOps - ((TID->Flags & M_PREDICABLE) ? 3 : 2));
unsigned JTI = JTOP.getJumpTableIndex();
MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
assert(JTI < JT.size());
// Thumb instructions are 2 byte aligned, but JT entries are 4 byte
// 4 aligned. The assembler / linker may add 2 byte padding just before
// the JT entries. The size does not include this padding; the
// constant islands pass does separate bookkeeping for it.
// FIXME: If we know the size of the function is less than (1 << 16) *2
// bytes, we can use 16-bit entries instead. Then there won't be an
// alignment issue.
return getNumJTEntries(JT, JTI) * 4 +
(MI->getOpcode()==ARM::tBR_JTr ? 2 : 4);
}
default:
// Otherwise, pseudo-instruction sizes are zero.
return 0;
}
}
}
}
/// GetFunctionSize - Returns the size of the specified MachineFunction.
///
unsigned ARM::GetFunctionSize(MachineFunction &MF) {
unsigned FnSize = 0;
for (MachineFunction::iterator MBBI = MF.begin(), E = MF.end();
MBBI != E; ++MBBI) {
MachineBasicBlock &MBB = *MBBI;
for (MachineBasicBlock::iterator I = MBB.begin(),E = MBB.end(); I != E; ++I)
FnSize += ARM::GetInstSize(I);
}
return FnSize;
}
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