1 //===-- X86InstrBuilder.h - Functions to aid building x86 insts -*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source 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/MachineInstrBuilder.h"
31 /// addDirectMem - This function is used to add a direct memory reference to the
32 /// current instruction -- that is, a dereference of an address in a register,
33 /// with no scale, index or displacement. An example is: DWORD PTR [EAX].
35 inline const MachineInstrBuilder &addDirectMem(const MachineInstrBuilder &MIB,
37 // Because memory references are always represented with four
38 // values, this adds: Reg, [1, NoReg, 0] to the instruction.
39 return MIB.addReg(Reg).addZImm(1).addReg(0).addSImm(0);
43 /// addRegOffset - This function is used to add a memory reference of the form
44 /// [Reg + Offset], i.e., one with no scale or index, but with a
45 /// displacement. An example is: DWORD PTR [EAX + 4].
47 inline const MachineInstrBuilder &addRegOffset(const MachineInstrBuilder &MIB,
48 unsigned Reg, int Offset) {
49 return MIB.addReg(Reg).addZImm(1).addReg(0).addSImm(Offset);
52 /// addFrameReference - This function is used to add a reference to the base of
53 /// an abstract object on the stack frame of the current function. This
54 /// reference has base register as the FrameIndex offset until it is resolved.
55 /// This allows a constant offset to be specified as well...
57 inline const MachineInstrBuilder &
58 addFrameReference(const MachineInstrBuilder &MIB, int FI, int Offset = 0) {
59 return MIB.addFrameIndex(FI).addZImm(1).addReg(0).addSImm(Offset);
62 /// addConstantPoolReference - This function is used to add a reference to the
63 /// base of a constant value spilled to the per-function constant pool. The
64 /// reference has base register ConstantPoolIndex offset which is retained until
65 /// either machine code emission or assembly output. This allows an optional
66 /// offset to be added as well.
68 inline const MachineInstrBuilder &
69 addConstantPoolReference(const MachineInstrBuilder &MIB, unsigned CPI,
71 return MIB.addConstantPoolIndex(CPI).addZImm(1).addReg(0).addSImm(Offset);
74 } // End llvm namespace