98 lines
2.8 KiB
C++
98 lines
2.8 KiB
C++
//===-- MipsEmitGPRestore.cpp - Emit GP Restore Instruction ---------------===//
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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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//
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// This pass emits instructions that restore $gp right
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// after jalr instructions.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "emit-gp-restore"
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#include "Mips.h"
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#include "MipsTargetMachine.h"
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#include "MipsMachineFunction.h"
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#include "llvm/CodeGen/MachineFunctionPass.h"
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#include "llvm/CodeGen/MachineInstrBuilder.h"
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#include "llvm/Target/TargetInstrInfo.h"
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#include "llvm/ADT/Statistic.h"
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using namespace llvm;
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namespace {
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struct Inserter : public MachineFunctionPass {
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TargetMachine &TM;
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const TargetInstrInfo *TII;
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static char ID;
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Inserter(TargetMachine &tm)
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: MachineFunctionPass(ID), TM(tm), TII(tm.getInstrInfo()) { }
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virtual const char *getPassName() const {
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return "Mips Emit GP Restore";
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}
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bool runOnMachineFunction(MachineFunction &F);
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};
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char Inserter::ID = 0;
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} // end of anonymous namespace
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bool Inserter::runOnMachineFunction(MachineFunction &F) {
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MipsFunctionInfo *MipsFI = F.getInfo<MipsFunctionInfo>();
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if ((TM.getRelocationModel() != Reloc::PIC_) ||
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(!MipsFI->globalBaseRegFixed()))
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return false;
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bool Changed = false;
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int FI = MipsFI->getGPFI();
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for (MachineFunction::iterator MFI = F.begin(), MFE = F.end();
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MFI != MFE; ++MFI) {
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MachineBasicBlock& MBB = *MFI;
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MachineBasicBlock::iterator I = MFI->begin();
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// If MBB is a landing pad, insert instruction that restores $gp after
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// EH_LABEL.
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if (MBB.isLandingPad()) {
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// Find EH_LABEL first.
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for (; I->getOpcode() != TargetOpcode::EH_LABEL; ++I) ;
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// Insert lw.
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++I;
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DebugLoc dl = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
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BuildMI(MBB, I, dl, TII->get(Mips::LW), Mips::GP).addFrameIndex(FI)
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.addImm(0);
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Changed = true;
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}
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while (I != MFI->end()) {
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if (I->getOpcode() != Mips::JALR) {
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++I;
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continue;
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}
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DebugLoc dl = I->getDebugLoc();
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// emit lw $gp, ($gp save slot on stack) after jalr
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BuildMI(MBB, ++I, dl, TII->get(Mips::LW), Mips::GP).addFrameIndex(FI)
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.addImm(0);
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Changed = true;
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}
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}
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return Changed;
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}
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/// createMipsEmitGPRestorePass - Returns a pass that emits instructions that
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/// restores $gp clobbered by jalr instructions.
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FunctionPass *llvm::createMipsEmitGPRestorePass(MipsTargetMachine &tm) {
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return new Inserter(tm);
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}
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