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//===-- X86InstrBuilder.h - Functions to aid building x86 insts -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file exposes functions that may be used with BuildMI from the
// MachineInstrBuilder.h file to handle X86'isms in a clean way.
//
// The BuildMem function may be used with the BuildMI function to add entire
// memory references in a single, typed, function call. X86 memory references
// can be very complex expressions (described in the README), so wrapping them
// up behind an easier to use interface makes sense. Descriptions of the
// functions are included below.
//
// For reference, the order of operands for memory references is:
// (Operand), Base, Scale, Index, Displacement.
//
//===----------------------------------------------------------------------===//
#ifndef X86INSTRBUILDER_H
#define X86INSTRBUILDER_H
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/PseudoSourceValue.h"
namespace llvm {
/// X86AddressMode - This struct holds a generalized full x86 address mode.
/// The base register can be a frame index, which will eventually be replaced
/// with BP or SP and Disp being offsetted accordingly. The displacement may
/// also include the offset of a global value.
struct X86AddressMode {
enum {
RegBase,
FrameIndexBase
} BaseType;
union {
unsigned Reg;
int FrameIndex;
} Base;
unsigned Scale;
unsigned IndexReg;
unsigned Disp;
GlobalValue *GV;
unsigned GVOpFlags;
X86AddressMode()
: BaseType(RegBase), Scale(1), IndexReg(0), Disp(0), GV(0), GVOpFlags(0) {
Base.Reg = 0;
}
};
/// addDirectMem - This function is used to add a direct memory reference to the
/// current instruction -- that is, a dereference of an address in a register,
/// with no scale, index or displacement. An example is: DWORD PTR [EAX].
///
inline const MachineInstrBuilder &addDirectMem(const MachineInstrBuilder &MIB,
unsigned Reg) {
// Because memory references are always represented with four
// values, this adds: Reg, [1, NoReg, 0] to the instruction.
return MIB.addReg(Reg).addImm(1).addReg(0).addImm(0);
}
inline const MachineInstrBuilder &addLeaOffset(const MachineInstrBuilder &MIB,
int Offset) {
return MIB.addImm(1).addReg(0).addImm(Offset);
}
inline const MachineInstrBuilder &addOffset(const MachineInstrBuilder &MIB,
int Offset) {
return addLeaOffset(MIB, Offset).addReg(0);
}
/// addRegOffset - This function is used to add a memory reference of the form
/// [Reg + Offset], i.e., one with no scale or index, but with a
/// displacement. An example is: DWORD PTR [EAX + 4].
///
inline const MachineInstrBuilder &addRegOffset(const MachineInstrBuilder &MIB,
unsigned Reg, bool isKill,
int Offset) {
return addOffset(MIB.addReg(Reg, getKillRegState(isKill)), Offset);
}
inline const MachineInstrBuilder &addLeaRegOffset(const MachineInstrBuilder &MIB,
unsigned Reg, bool isKill,
int Offset) {
return addLeaOffset(MIB.addReg(Reg, getKillRegState(isKill)), Offset);
}
/// addRegReg - This function is used to add a memory reference of the form:
/// [Reg + Reg].
inline const MachineInstrBuilder &addRegReg(const MachineInstrBuilder &MIB,
unsigned Reg1, bool isKill1,
unsigned Reg2, bool isKill2) {
return MIB.addReg(Reg1, getKillRegState(isKill1)).addImm(1)
.addReg(Reg2, getKillRegState(isKill2)).addImm(0);
}
inline const MachineInstrBuilder &addLeaAddress(const MachineInstrBuilder &MIB,
const X86AddressMode &AM) {
assert (AM.Scale == 1 || AM.Scale == 2 || AM.Scale == 4 || AM.Scale == 8);
if (AM.BaseType == X86AddressMode::RegBase)
MIB.addReg(AM.Base.Reg);
else if (AM.BaseType == X86AddressMode::FrameIndexBase)
MIB.addFrameIndex(AM.Base.FrameIndex);
else
assert (0);
MIB.addImm(AM.Scale).addReg(AM.IndexReg);
if (AM.GV)
return MIB.addGlobalAddress(AM.GV, AM.Disp, AM.GVOpFlags);
else
return MIB.addImm(AM.Disp);
}
inline const MachineInstrBuilder &addFullAddress(const MachineInstrBuilder &MIB,
const X86AddressMode &AM) {
return addLeaAddress(MIB, AM).addReg(0);
}
/// addFrameReference - This function is used to add a reference to the base of
/// an abstract object on the stack frame of the current function. This
/// reference has base register as the FrameIndex offset until it is resolved.
/// This allows a constant offset to be specified as well...
///
inline const MachineInstrBuilder &
addFrameReference(const MachineInstrBuilder &MIB, int FI, int Offset = 0) {
MachineInstr *MI = MIB;
MachineFunction &MF = *MI->getParent()->getParent();
MachineFrameInfo &MFI = *MF.getFrameInfo();
const TargetInstrDesc &TID = MI->getDesc();
unsigned Flags = 0;
if (TID.mayLoad())
Flags |= MachineMemOperand::MOLoad;
if (TID.mayStore())
Flags |= MachineMemOperand::MOStore;
MachineMemOperand MMO(PseudoSourceValue::getFixedStack(FI),
Flags,
MFI.getObjectOffset(FI) + Offset,
MFI.getObjectSize(FI),
MFI.getObjectAlignment(FI));
return addOffset(MIB.addFrameIndex(FI), Offset)
.addMemOperand(MMO);
}
/// addConstantPoolReference - This function is used to add a reference to the
/// base of a constant value spilled to the per-function constant pool. The
/// reference uses the abstract ConstantPoolIndex which is retained until
/// either machine code emission or assembly output. In PIC mode on x86-32,
/// the GlobalBaseReg parameter can be used to make this a
/// GlobalBaseReg-relative reference.
///
inline const MachineInstrBuilder &
addConstantPoolReference(const MachineInstrBuilder &MIB, unsigned CPI,
unsigned GlobalBaseReg, unsigned char OpFlags) {
//FIXME: factor this
return MIB.addReg(GlobalBaseReg).addImm(1).addReg(0)
.addConstantPoolIndex(CPI, 0, OpFlags).addReg(0);
}
} // End llvm namespace
#endif
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