1 //===-- X86InstrBuilder.h - Functions to aid building x86 insts -*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file exposes functions that may be used with BuildMI from the
11 // MachineInstrBuilder.h file to handle X86'isms in a clean way.
13 // The BuildMem function may be used with the BuildMI function to add entire
14 // memory references in a single, typed, function call. X86 memory references
15 // can be very complex expressions (described in the README), so wrapping them
16 // up behind an easier to use interface makes sense. Descriptions of the
17 // functions are included below.
19 // For reference, the order of operands for memory references is:
20 // (Operand), Base, Scale, Index, Displacement.
22 //===----------------------------------------------------------------------===//
24 #ifndef X86INSTRBUILDER_H
25 #define X86INSTRBUILDER_H
27 #include "llvm/CodeGen/MachineFrameInfo.h"
28 #include "llvm/CodeGen/MachineInstrBuilder.h"
29 #include "llvm/CodeGen/PseudoSourceValue.h"
33 /// X86AddressMode - This struct holds a generalized full x86 address mode.
34 /// The base register can be a frame index, which will eventually be replaced
35 /// with BP or SP and Disp being offsetted accordingly. The displacement may
36 /// also include the offset of a global value.
37 struct X86AddressMode {
53 X86AddressMode() : BaseType(RegBase), Scale(1), IndexReg(0), Disp(0), GV(0) {
58 /// addDirectMem - This function is used to add a direct memory reference to the
59 /// current instruction -- that is, a dereference of an address in a register,
60 /// with no scale, index or displacement. An example is: DWORD PTR [EAX].
62 inline const MachineInstrBuilder &addDirectMem(const MachineInstrBuilder &MIB,
64 // Because memory references are always represented with four
65 // values, this adds: Reg, [1, NoReg, 0] to the instruction.
66 return MIB.addReg(Reg).addImm(1).addReg(0).addImm(0);
70 /// addRegOffset - This function is used to add a memory reference of the form
71 /// [Reg + Offset], i.e., one with no scale or index, but with a
72 /// displacement. An example is: DWORD PTR [EAX + 4].
74 inline const MachineInstrBuilder &addRegOffset(const MachineInstrBuilder &MIB,
75 unsigned Reg, bool isKill,
77 return MIB.addReg(Reg, false, false, isKill)
78 .addImm(1).addReg(0).addImm(Offset);
81 /// addRegReg - This function is used to add a memory reference of the form:
83 inline const MachineInstrBuilder &addRegReg(const MachineInstrBuilder &MIB,
84 unsigned Reg1, bool isKill1,
85 unsigned Reg2, bool isKill2) {
86 return MIB.addReg(Reg1, false, false, isKill1).addImm(1)
87 .addReg(Reg2, false, false, isKill2).addImm(0);
90 inline const MachineInstrBuilder &addFullAddress(const MachineInstrBuilder &MIB,
91 const X86AddressMode &AM) {
92 assert (AM.Scale == 1 || AM.Scale == 2 || AM.Scale == 4 || AM.Scale == 8);
94 if (AM.BaseType == X86AddressMode::RegBase)
95 MIB.addReg(AM.Base.Reg);
96 else if (AM.BaseType == X86AddressMode::FrameIndexBase)
97 MIB.addFrameIndex(AM.Base.FrameIndex);
100 MIB.addImm(AM.Scale).addReg(AM.IndexReg);
102 return MIB.addGlobalAddress(AM.GV, AM.Disp);
104 return MIB.addImm(AM.Disp);
107 /// addFrameReference - This function is used to add a reference to the base of
108 /// an abstract object on the stack frame of the current function. This
109 /// reference has base register as the FrameIndex offset until it is resolved.
110 /// This allows a constant offset to be specified as well...
112 inline const MachineInstrBuilder &
113 addFrameReference(const MachineInstrBuilder &MIB, int FI, int Offset = 0) {
114 MachineInstr *MI = MIB;
115 MachineFunction &MF = *MI->getParent()->getParent();
116 MachineFrameInfo &MFI = *MF.getFrameInfo();
117 const TargetInstrDesc &TID = MI->getDesc();
120 Flags |= MachineMemOperand::MOLoad;
122 Flags |= MachineMemOperand::MOStore;
123 MachineMemOperand MMO(PseudoSourceValue::getFixedStack(FI),
125 MFI.getObjectOffset(FI) + Offset,
126 MFI.getObjectSize(FI),
127 MFI.getObjectAlignment(FI));
128 return MIB.addFrameIndex(FI).addImm(1).addReg(0).addImm(Offset)
132 /// addConstantPoolReference - This function is used to add a reference to the
133 /// base of a constant value spilled to the per-function constant pool. The
134 /// reference uses the abstract ConstantPoolIndex which is retained until
135 /// either machine code emission or assembly output. In PIC mode on x86-32,
136 /// the GlobalBaseReg parameter can be used to make this a
137 /// GlobalBaseReg-relative reference.
139 inline const MachineInstrBuilder &
140 addConstantPoolReference(const MachineInstrBuilder &MIB, unsigned CPI,
141 unsigned GlobalBaseReg = 0) {
142 return MIB.addReg(GlobalBaseReg).addImm(1).addReg(0).addConstantPoolIndex(CPI);
145 } // End llvm namespace