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ed6902ca89
because arguments start two stack slots off of EBP. Break out of the for loop once the argument is found. Increment the counter at the end of the loop instead of the beginning. Use addRegOffset and compute the scale * index part at compile time instead of using the fancy load instruction. Just because an instruction set has wacky addressing modes doesn't mean we ought to use them (at least, if you believe Dave Patterson). lib/Target/X86/X86InstrBuilder.h: Add some comments. test/Regression/Jello/test-loadstore.ll: Let main return int 0. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4999 91177308-0d34-0410-b5e6-96231b3b80d8
42 lines
1.8 KiB
C++
42 lines
1.8 KiB
C++
//===-- X86InstrBuilder.h - Functions to aid building x86 insts -*- C++ -*-===//
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//
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// This file exposes functions that may be used with BuildMI from the
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// MachineInstrBuilder.h file to handle X86'isms in a clean way.
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//
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// The BuildMem function may be used with the BuildMI function to add entire
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// memory references in a single, typed, function call. X86 memory references
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// can be very complex expressions (described in the README), so wrapping them
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// up behind an easier to use interface makes sense. Descriptions of the
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// functions are included below.
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//
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// For reference, the order of operands for memory references is:
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// (Operand), Base, Scale, Index, Displacement.
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//
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//===----------------------------------------------------------------------===//
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#ifndef X86INSTRBUILDER_H
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#define X86INSTRBUILDER_H
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#include "llvm/CodeGen/MachineInstrBuilder.h"
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/// addDirectMem - This function is used to add a direct memory reference to the
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/// current instruction -- that is, a dereference of an address in a register, with
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/// no scale, index or displacement. An example is: DWORD PTR [EAX].
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inline const MachineInstrBuilder &addDirectMem(const MachineInstrBuilder &MIB,
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unsigned Reg) {
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// Because memory references are always represented with four
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// values, this adds: Reg, [1, NoReg, 0] to the instruction.
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return MIB.addReg(Reg).addZImm(1).addMReg(0).addSImm(0);
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}
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/// addRegOffset - This function is used to add a memory reference of
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/// the form [Reg + Offset], i.e., one with no scale or index, but
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/// with a displacement. An example is: DWORD PTR [EAX + 4].
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inline const MachineInstrBuilder &addRegOffset(const MachineInstrBuilder &MIB,
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unsigned Reg, unsigned Offset) {
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return MIB.addReg(Reg).addZImm(1).addMReg(0).addSImm(Offset);
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}
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#endif
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