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648f00c2f0
reserving a physical register ($gp or $28) for that purpose. This will completely eliminate loads that restore the value of $gp after every function call, if the register allocator assigns a callee-saved register, or eliminate unnecessary loads if it assigns a temporary register. example: .cpload $25 // set $gp. ... .cprestore 16 // store $gp to stack slot 16($sp). ... jalr $25 // function call. clobbers $gp. lw $gp, 16($sp) // not emitted if callee-saved reg is chosen. ... lw $2, 4($gp) ... jalr $25 // function call. lw $gp, 16($sp) // not emitted if $gp is not live after this instruction. ... git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151402 91177308-0d34-0410-b5e6-96231b3b80d8
51 lines
1.7 KiB
C++
51 lines
1.7 KiB
C++
//===-- MipsMCInstLower.h - Lower MachineInstr to MCInst -------*- C++ -*--===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#ifndef MIPSMCINSTLOWER_H
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#define MIPSMCINSTLOWER_H
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/CodeGen/MachineOperand.h"
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#include "llvm/Support/Compiler.h"
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namespace llvm {
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class MCAsmInfo;
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class MCContext;
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class MCInst;
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class MCOperand;
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class MCSymbol;
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class MachineInstr;
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class MachineFunction;
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class Mangler;
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class MipsAsmPrinter;
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/// MipsMCInstLower - This class is used to lower an MachineInstr into an
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// MCInst.
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class LLVM_LIBRARY_VISIBILITY MipsMCInstLower {
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typedef MachineOperand::MachineOperandType MachineOperandType;
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MCContext &Ctx;
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Mangler *Mang;
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MipsAsmPrinter &AsmPrinter;
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public:
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MipsMCInstLower(Mangler *mang, const MachineFunction &MF,
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MipsAsmPrinter &asmprinter);
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void Lower(const MachineInstr *MI, MCInst &OutMI) const;
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void LowerCPLOAD(const MachineInstr *MI, SmallVector<MCInst, 4>& MCInsts);
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void LowerCPRESTORE(const MachineInstr *MI, SmallVector<MCInst, 4>& MCInsts);
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void LowerUnalignedLoadStore(const MachineInstr *MI,
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SmallVector<MCInst, 4>& MCInsts);
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void LowerSETGP01(const MachineInstr *MI, SmallVector<MCInst, 4>& MCInsts);
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private:
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MCOperand LowerSymbolOperand(const MachineOperand &MO,
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MachineOperandType MOTy, unsigned Offset) const;
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MCOperand LowerOperand(const MachineOperand& MO, unsigned offset = 0) const;
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};
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}
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#endif
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