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//===-- ResetMachineFunctionPass.cpp - Reset Machine Function ----*- C++ -*-==//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
/// \file
/// This file implements a pass that will conditionally reset a machine
/// function as if it was just created. This is used to provide a fallback
/// mechanism when GlobalISel fails, thus the condition for the reset to
/// happen is that the MachineFunction has the FailedISel property.
//===----------------------------------------------------------------------===//
#include "llvm/ADT/ScopeExit.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/StackProtector.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/InitializePasses.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
#define DEBUG_TYPE "reset-machine-function"
STATISTIC(NumFunctionsReset, "Number of functions reset");
STATISTIC(NumFunctionsVisited, "Number of functions visited");
namespace {
class ResetMachineFunction : public MachineFunctionPass {
/// Tells whether or not this pass should emit a fallback
/// diagnostic when it resets a function.
bool EmitFallbackDiag;
/// Whether we should abort immediately instead of resetting the function.
bool AbortOnFailedISel;
public:
static char ID; // Pass identification, replacement for typeid
ResetMachineFunction(bool EmitFallbackDiag = false,
bool AbortOnFailedISel = false)
: MachineFunctionPass(ID), EmitFallbackDiag(EmitFallbackDiag),
AbortOnFailedISel(AbortOnFailedISel) {}
StringRef getPassName() const override { return "ResetMachineFunction"; }
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addPreserved<StackProtector>();
MachineFunctionPass::getAnalysisUsage(AU);
}
bool runOnMachineFunction(MachineFunction &MF) override {
++NumFunctionsVisited;
// No matter what happened, whether we successfully selected the function
// or not, nothing is going to use the vreg types after us. Make sure they
// disappear.
auto ClearVRegTypesOnReturn =
make_scope_exit([&MF]() { MF.getRegInfo().clearVirtRegTypes(); });
if (MF.getProperties().hasProperty(
MachineFunctionProperties::Property::FailedISel)) {
if (AbortOnFailedISel)
report_fatal_error("Instruction selection failed");
LLVM_DEBUG(dbgs() << "Resetting: " << MF.getName() << '\n');
++NumFunctionsReset;
MF.reset();
MF.initTargetMachineFunctionInfo(MF.getSubtarget());
if (EmitFallbackDiag) {
const Function &F = MF.getFunction();
DiagnosticInfoISelFallback DiagFallback(F);
F.getContext().diagnose(DiagFallback);
}
return true;
}
return false;
}
};
} // end anonymous namespace
char ResetMachineFunction::ID = 0;
INITIALIZE_PASS(ResetMachineFunction, DEBUG_TYPE,
"Reset machine function if ISel failed", false, false)
MachineFunctionPass *
llvm::createResetMachineFunctionPass(bool EmitFallbackDiag = false,
bool AbortOnFailedISel = false) {
return new ResetMachineFunction(EmitFallbackDiag, AbortOnFailedISel);
}
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