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//===- Thumb2RegisterInfo.cpp - Thumb-2 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 Thumb-2 implementation of the TargetRegisterInfo class.
//
//===----------------------------------------------------------------------===//
#include "ARM.h"
#include "ARMAddressingModes.h"
#include "ARMBaseInstrInfo.h"
#include "ARMMachineFunctionInfo.h"
#include "ARMSubtarget.h"
#include "Thumb2InstrInfo.h"
#include "Thumb2RegisterInfo.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/Target/TargetFrameInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ErrorHandling.h"
using namespace llvm;
Thumb2RegisterInfo::Thumb2RegisterInfo(const ARMBaseInstrInfo &tii,
const ARMSubtarget &sti)
: ARMBaseRegisterInfo(tii, sti) {
}
/// emitLoadConstPool - Emits a load from constpool to materialize the
/// specified immediate.
void Thumb2RegisterInfo::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 =
MF.getFunction()->getContext().getConstantInt(Type::Int32Ty, Val);
unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
BuildMI(MBB, MBBI, dl, TII.get(ARM::t2LDRpci))
.addReg(DestReg, getDefRegState(true), SubIdx)
.addConstantPoolIndex(Idx).addImm((int64_t)ARMCC::AL).addReg(0);
}
static unsigned
negativeOffsetOpcode(unsigned opcode)
{
switch (opcode) {
case ARM::t2LDRi12: return ARM::t2LDRi8;
case ARM::t2LDRHi12: return ARM::t2LDRHi8;
case ARM::t2LDRBi12: return ARM::t2LDRBi8;
case ARM::t2LDRSHi12: return ARM::t2LDRSHi8;
case ARM::t2LDRSBi12: return ARM::t2LDRSBi8;
case ARM::t2STRi12: return ARM::t2STRi8;
case ARM::t2STRBi12: return ARM::t2STRBi8;
case ARM::t2STRHi12: return ARM::t2STRHi8;
case ARM::t2LDRi8:
case ARM::t2LDRHi8:
case ARM::t2LDRBi8:
case ARM::t2LDRSHi8:
case ARM::t2LDRSBi8:
case ARM::t2STRi8:
case ARM::t2STRBi8:
case ARM::t2STRHi8:
return opcode;
default:
break;
}
return 0;
}
static unsigned
positiveOffsetOpcode(unsigned opcode)
{
switch (opcode) {
case ARM::t2LDRi8: return ARM::t2LDRi12;
case ARM::t2LDRHi8: return ARM::t2LDRHi12;
case ARM::t2LDRBi8: return ARM::t2LDRBi12;
case ARM::t2LDRSHi8: return ARM::t2LDRSHi12;
case ARM::t2LDRSBi8: return ARM::t2LDRSBi12;
case ARM::t2STRi8: return ARM::t2STRi12;
case ARM::t2STRBi8: return ARM::t2STRBi12;
case ARM::t2STRHi8: return ARM::t2STRHi12;
case ARM::t2LDRi12:
case ARM::t2LDRHi12:
case ARM::t2LDRBi12:
case ARM::t2LDRSHi12:
case ARM::t2LDRSBi12:
case ARM::t2STRi12:
case ARM::t2STRBi12:
case ARM::t2STRHi12:
return opcode;
default:
break;
}
return 0;
}
static unsigned
immediateOffsetOpcode(unsigned opcode)
{
switch (opcode) {
case ARM::t2LDRs: return ARM::t2LDRi12;
case ARM::t2LDRHs: return ARM::t2LDRHi12;
case ARM::t2LDRBs: return ARM::t2LDRBi12;
case ARM::t2LDRSHs: return ARM::t2LDRSHi12;
case ARM::t2LDRSBs: return ARM::t2LDRSBi12;
case ARM::t2STRs: return ARM::t2STRi12;
case ARM::t2STRBs: return ARM::t2STRBi12;
case ARM::t2STRHs: return ARM::t2STRHi12;
case ARM::t2LDRi12:
case ARM::t2LDRHi12:
case ARM::t2LDRBi12:
case ARM::t2LDRSHi12:
case ARM::t2LDRSBi12:
case ARM::t2STRi12:
case ARM::t2STRBi12:
case ARM::t2STRHi12:
case ARM::t2LDRi8:
case ARM::t2LDRHi8:
case ARM::t2LDRBi8:
case ARM::t2LDRSHi8:
case ARM::t2LDRSBi8:
case ARM::t2STRi8:
case ARM::t2STRBi8:
case ARM::t2STRHi8:
return opcode;
default:
break;
}
return 0;
}
bool Thumb2RegisterInfo::
requiresRegisterScavenging(const MachineFunction &MF) const {
return true;
}
int Thumb2RegisterInfo::
rewriteFrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
unsigned FrameReg, int Offset) const
{
unsigned Opcode = MI.getOpcode();
const TargetInstrDesc &Desc = MI.getDesc();
unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
bool isSub = false;
// Memory operands in inline assembly always use AddrModeT2_i12
if (Opcode == ARM::INLINEASM)
AddrMode = ARMII::AddrModeT2_i12; // FIXME. mode for thumb2?
if (Opcode == getOpcode(ARMII::ADDri)) {
Offset += MI.getOperand(FrameRegIdx+1).getImm();
if (Offset == 0) {
// Turn it into a move.
MI.setDesc(TII.get(getOpcode(ARMII::MOVr)));
MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
MI.RemoveOperand(FrameRegIdx+1);
return 0;
} else if (Offset < 0) {
Offset = -Offset;
isSub = true;
MI.setDesc(TII.get(getOpcode(ARMII::SUBri)));
}
// Common case: small offset, fits into instruction.
if (ARM_AM::getT2SOImmVal(Offset) != -1) {
// Replace the FrameIndex with sp / fp
MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
MI.getOperand(FrameRegIdx+1).ChangeToImmediate(Offset);
return 0;
}
// Otherwise, extract 8 adjacent bits from the immediate into this
// t2ADDri/t2SUBri.
unsigned RotAmt = CountLeadingZeros_32(Offset);
if (RotAmt > 24)
RotAmt = 24;
unsigned ThisImmVal = Offset & ARM_AM::rotr32(0xff000000U, RotAmt);
// We will handle these bits from offset, clear them.
Offset &= ~ThisImmVal;
assert(ARM_AM::getT2SOImmVal(ThisImmVal) != -1 &&
"Bit extraction didn't work?");
MI.getOperand(FrameRegIdx+1).ChangeToImmediate(ThisImmVal);
} else {
// AddrModeT2_so cannot handle any offset. If there is no offset
// register then we change to an immediate version.
if (AddrMode == ARMII::AddrModeT2_so) {
unsigned OffsetReg = MI.getOperand(FrameRegIdx+1).getReg();
if (OffsetReg != 0) {
MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
return Offset;
}
MI.RemoveOperand(FrameRegIdx+1);
MI.getOperand(FrameRegIdx+1).ChangeToImmediate(0);
Opcode = immediateOffsetOpcode(Opcode);
AddrMode = ARMII::AddrModeT2_i12;
}
// Neon and FP address modes are handled by the base ARM version...
if ((AddrMode != ARMII::AddrModeT2_i8) &&
(AddrMode != ARMII::AddrModeT2_i12)) {
return ARMBaseRegisterInfo::rewriteFrameIndex(MI, FrameRegIdx,
FrameReg, Offset);
}
unsigned NumBits = 0;
Offset += MI.getOperand(FrameRegIdx+1).getImm();
// i8 supports only negative, and i12 supports only positive, so
// based on Offset sign convert Opcode to the appropriate
// instruction
if (Offset < 0) {
Opcode = negativeOffsetOpcode(Opcode);
NumBits = 8;
isSub = true;
Offset = -Offset;
}
else {
Opcode = positiveOffsetOpcode(Opcode);
NumBits = 12;
}
if (Opcode) {
MI.setDesc(TII.get(Opcode));
MachineOperand &ImmOp = MI.getOperand(FrameRegIdx+1);
// Attempt to fold address computation
// Common case: small offset, fits into instruction.
unsigned Mask = (1 << NumBits) - 1;
if ((unsigned)Offset <= Mask) {
// Replace the FrameIndex with fp/sp
MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
ImmOp.ChangeToImmediate((isSub) ? -Offset : Offset);
return 0;
}
// Otherwise, offset doesn't fit. Pull in what we can to simplify
unsigned ImmedOffset = Offset & Mask;
ImmOp.ChangeToImmediate((isSub) ? -ImmedOffset : ImmedOffset);
Offset &= ~Mask;
}
}
return (isSub) ? -Offset : Offset;
}
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