Coverage Report

Created: 2019-07-24 05:18

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/lib/CodeGen/ResetMachineFunctionPass.cpp
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//===-- ResetMachineFunctionPass.cpp - Reset Machine Function ----*- C++ -*-==//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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/// \file
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/// This file implements a pass that will conditionally reset a machine
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/// function as if it was just created. This is used to provide a fallback
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/// mechanism when GlobalISel fails, thus the condition for the reset to
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/// happen is that the MachineFunction has the FailedISel property.
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//===----------------------------------------------------------------------===//
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#include "llvm/ADT/ScopeExit.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineFunctionPass.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/CodeGen/StackProtector.h"
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/IR/DiagnosticInfo.h"
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#include "llvm/Support/Debug.h"
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using namespace llvm;
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#define DEBUG_TYPE "reset-machine-function"
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STATISTIC(NumFunctionsReset, "Number of functions reset");
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STATISTIC(NumFunctionsVisited, "Number of functions visited");
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namespace {
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  class ResetMachineFunction : public MachineFunctionPass {
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    /// Tells whether or not this pass should emit a fallback
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    /// diagnostic when it resets a function.
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    bool EmitFallbackDiag;
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    /// Whether we should abort immediately instead of resetting the function.
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    bool AbortOnFailedISel;
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  public:
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    static char ID; // Pass identification, replacement for typeid
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    ResetMachineFunction(bool EmitFallbackDiag = false,
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                         bool AbortOnFailedISel = false)
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        : MachineFunctionPass(ID), EmitFallbackDiag(EmitFallbackDiag),
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          AbortOnFailedISel(AbortOnFailedISel) {}
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    StringRef getPassName() const override { return "ResetMachineFunction"; }
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    void getAnalysisUsage(AnalysisUsage &AU) const override {
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      AU.addPreserved<StackProtector>();
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      MachineFunctionPass::getAnalysisUsage(AU);
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    }
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    bool runOnMachineFunction(MachineFunction &MF) override {
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      ++NumFunctionsVisited;
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      // No matter what happened, whether we successfully selected the function
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      // or not, nothing is going to use the vreg types after us. Make sure they
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      // disappear.
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      auto ClearVRegTypesOnReturn =
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          make_scope_exit([&MF]() { MF.getRegInfo().clearVirtRegTypes(); });
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      if (MF.getProperties().hasProperty(
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              MachineFunctionProperties::Property::FailedISel)) {
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        if (AbortOnFailedISel)
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          report_fatal_error("Instruction selection failed");
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        LLVM_DEBUG(dbgs() << "Resetting: " << MF.getName() << '\n');
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        ++NumFunctionsReset;
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        MF.reset();
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        if (EmitFallbackDiag) {
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          const Function &F = MF.getFunction();
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          DiagnosticInfoISelFallback DiagFallback(F);
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          F.getContext().diagnose(DiagFallback);
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        }
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        return true;
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      }
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      return false;
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    }
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  };
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} // end anonymous namespace
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char ResetMachineFunction::ID = 0;
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INITIALIZE_PASS(ResetMachineFunction, DEBUG_TYPE,
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                "Reset machine function if ISel failed", false, false)
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MachineFunctionPass *
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llvm::createResetMachineFunctionPass(bool EmitFallbackDiag = false,
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                                     bool AbortOnFailedISel = false) {
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  return new ResetMachineFunction(EmitFallbackDiag, AbortOnFailedISel);
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}