llvm-6502/lib/Target/ARM/ARMMCInstLower.cpp

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//===-- ARMMCInstLower.cpp - Convert ARM MachineInstr to an MCInst --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains code to lower ARM MachineInstrs to their corresponding
// MCInst records.
//
//===----------------------------------------------------------------------===//
#include "ARM.h"
#include "ARMAsmPrinter.h"
#include "MCTargetDesc/ARMBaseInfo.h"
#include "MCTargetDesc/ARMMCExpr.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Mangler.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
using namespace llvm;
MCOperand ARMAsmPrinter::GetSymbolRef(const MachineOperand &MO,
const MCSymbol *Symbol) {
const MCExpr *Expr;
unsigned Option = MO.getTargetFlags() & ARMII::MO_OPTION_MASK;
switch (Option) {
default: {
Expr = MCSymbolRefExpr::Create(Symbol, MCSymbolRefExpr::VK_None,
OutContext);
switch (Option) {
default: llvm_unreachable("Unknown target flag on symbol operand");
case ARMII::MO_NO_FLAG:
break;
case ARMII::MO_LO16:
Expr = MCSymbolRefExpr::Create(Symbol, MCSymbolRefExpr::VK_None,
OutContext);
Expr = ARMMCExpr::CreateLower16(Expr, OutContext);
break;
case ARMII::MO_HI16:
Expr = MCSymbolRefExpr::Create(Symbol, MCSymbolRefExpr::VK_None,
OutContext);
Expr = ARMMCExpr::CreateUpper16(Expr, OutContext);
break;
}
break;
}
case ARMII::MO_PLT:
Expr = MCSymbolRefExpr::Create(Symbol, MCSymbolRefExpr::VK_PLT,
OutContext);
break;
}
if (!MO.isJTI() && MO.getOffset())
Expr = MCBinaryExpr::CreateAdd(Expr,
MCConstantExpr::Create(MO.getOffset(),
OutContext),
OutContext);
return MCOperand::CreateExpr(Expr);
}
bool ARMAsmPrinter::lowerOperand(const MachineOperand &MO,
MCOperand &MCOp) {
switch (MO.getType()) {
default: llvm_unreachable("unknown operand type");
case MachineOperand::MO_Register:
// Ignore all non-CPSR implicit register operands.
if (MO.isImplicit() && MO.getReg() != ARM::CPSR)
return false;
assert(!MO.getSubReg() && "Subregs should be eliminated!");
MCOp = MCOperand::CreateReg(MO.getReg());
break;
case MachineOperand::MO_Immediate:
MCOp = MCOperand::CreateImm(MO.getImm());
break;
case MachineOperand::MO_MachineBasicBlock:
MCOp = MCOperand::CreateExpr(MCSymbolRefExpr::Create(
MO.getMBB()->getSymbol(), OutContext));
break;
case MachineOperand::MO_GlobalAddress: {
MCOp = GetSymbolRef(MO,
GetARMGVSymbol(MO.getGlobal(), MO.getTargetFlags()));
break;
}
case MachineOperand::MO_ExternalSymbol:
MCOp = GetSymbolRef(MO,
GetExternalSymbolSymbol(MO.getSymbolName()));
break;
case MachineOperand::MO_JumpTableIndex:
MCOp = GetSymbolRef(MO, GetJTISymbol(MO.getIndex()));
break;
case MachineOperand::MO_ConstantPoolIndex:
MCOp = GetSymbolRef(MO, GetCPISymbol(MO.getIndex()));
break;
case MachineOperand::MO_BlockAddress:
MCOp = GetSymbolRef(MO, GetBlockAddressSymbol(MO.getBlockAddress()));
break;
case MachineOperand::MO_FPImmediate: {
APFloat Val = MO.getFPImm()->getValueAPF();
bool ignored;
Val.convert(APFloat::IEEEdouble, APFloat::rmTowardZero, &ignored);
MCOp = MCOperand::CreateFPImm(Val.convertToDouble());
break;
}
case MachineOperand::MO_RegisterMask:
// Ignore call clobbers.
return false;
}
return true;
}
void llvm::LowerARMMachineInstrToMCInst(const MachineInstr *MI, MCInst &OutMI,
ARMAsmPrinter &AP) {
OutMI.setOpcode(MI->getOpcode());
// In the MC layer, we keep modified immediates in their encoded form
bool EncodeImms = false;
switch (MI->getOpcode()) {
default: break;
case ARM::MOVi:
case ARM::MVNi:
case ARM::CMPri:
case ARM::CMNri:
case ARM::TSTri:
case ARM::TEQri:
case ARM::MSRi:
case ARM::ADCri:
case ARM::ADDri:
case ARM::ADDSri:
case ARM::SBCri:
case ARM::SUBri:
case ARM::SUBSri:
case ARM::ANDri:
case ARM::ORRri:
case ARM::EORri:
case ARM::BICri:
case ARM::RSBri:
case ARM::RSBSri:
case ARM::RSCri:
EncodeImms = true;
break;
}
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
MCOperand MCOp;
if (AP.lowerOperand(MO, MCOp)) {
if (MCOp.isImm() && EncodeImms) {
int32_t Enc = ARM_AM::getSOImmVal(MCOp.getImm());
if (Enc != -1)
MCOp.setImm(Enc);
}
OutMI.addOperand(MCOp);
}
}
}