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//===-- llvm/CodeGen/GlobalISel/MachineLegalizePass.cpp -------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// \file This file implements the LegalizeHelper class to legalize individual
/// instructions and the MachineLegalizePass wrapper pass for the primary
/// legalization.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/GlobalISel/MachineLegalizePass.h"
#include "llvm/CodeGen/GlobalISel/MachineLegalizeHelper.h"
#include "llvm/CodeGen/GlobalISel/MachineLegalizer.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetPassConfig.h"
#include "llvm/Support/Debug.h"
#include "llvm/Target/TargetSubtargetInfo.h"
#define DEBUG_TYPE "legalize-mir"
using namespace llvm;
char MachineLegalizePass::ID = 0;
INITIALIZE_PASS_BEGIN(MachineLegalizePass, DEBUG_TYPE,
"Legalize the Machine IR a function's Machine IR", false,
false)
INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
INITIALIZE_PASS_END(MachineLegalizePass, DEBUG_TYPE,
"Legalize the Machine IR a function's Machine IR", false,
false)
MachineLegalizePass::MachineLegalizePass() : MachineFunctionPass(ID) {
initializeMachineLegalizePassPass(*PassRegistry::getPassRegistry());
}
void MachineLegalizePass::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<TargetPassConfig>();
MachineFunctionPass::getAnalysisUsage(AU);
}
void MachineLegalizePass::init(MachineFunction &MF) {
}
bool MachineLegalizePass::runOnMachineFunction(MachineFunction &MF) {
// If the ISel pipeline failed, do not bother running that pass.
if (MF.getProperties().hasProperty(
MachineFunctionProperties::Property::FailedISel))
return false;
DEBUG(dbgs() << "Legalize Machine IR for: " << MF.getName() << '\n');
init(MF);
const TargetPassConfig &TPC = getAnalysis<TargetPassConfig>();
const MachineLegalizer &Legalizer = *MF.getSubtarget().getMachineLegalizer();
MachineLegalizeHelper Helper(MF);
// FIXME: an instruction may need more than one pass before it is legal. For
// example on most architectures <3 x i3> is doubly-illegal. It would
// typically proceed along a path like: <3 x i3> -> <3 x i8> -> <8 x i8>. We
// probably want a worklist of instructions rather than naive iterate until
// convergence for performance reasons.
bool Changed = false;
MachineBasicBlock::iterator NextMI;
for (auto &MBB : MF)
for (auto MI = MBB.begin(); MI != MBB.end(); MI = NextMI) {
// Get the next Instruction before we try to legalize, because there's a
// good chance MI will be deleted.
NextMI = std::next(MI);
// Only legalize pre-isel generic instructions: others don't have types
// and are assumed to be legal.
if (!isPreISelGenericOpcode(MI->getOpcode()))
continue;
auto Res = Helper.legalizeInstr(*MI, Legalizer);
// Error out if we couldn't legalize this instruction. We may want to fall
// back to DAG ISel instead in the future.
if (Res == MachineLegalizeHelper::UnableToLegalize) {
if (!TPC.isGlobalISelAbortEnabled()) {
MF.getProperties().set(
MachineFunctionProperties::Property::FailedISel);
return false;
}
std::string Msg;
raw_string_ostream OS(Msg);
OS << "unable to legalize instruction: ";
MI->print(OS);
report_fatal_error(OS.str());
}
Changed |= Res == MachineLegalizeHelper::Legalized;
}
return Changed;
}
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