lib/IR/OptBisect.cpp

   1 //===- llvm/IR/OptBisect/Bisect.cpp - LLVM Bisect support -----------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 /// \file
  10 /// This file implements support for a bisecting optimizations based on a
  11 /// command line option.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/IR/OptBisect.h"
  16 #include "llvm/ADT/StringRef.h"
  17 #include "llvm/Pass.h"
  18 #include "llvm/Support/CommandLine.h"
  19 #include "llvm/Support/raw_ostream.h"
  20 #include <cassert>
  21 #include <limits>
  22 #include <string>
  23
  24 using namespace llvm;
  25
  26 static cl::opt<int> OptBisectLimit("opt-bisect-limit", cl::Hidden,
  27                                    cl::init(std::numeric_limits<int>::max()),
  28                                    cl::Optional,
  29                                    cl::desc("Maximum optimization to perform"));
  30
  31 OptBisect::OptBisect() : OptPassGate() {
  32   BisectEnabled = OptBisectLimit != std::numeric_limits<int>::max();
  33 }
  34
  35 static void printPassMessage(const StringRef &Name, int PassNum,
  36                              StringRef TargetDesc, bool Running) {
  37   StringRef Status = Running ? "" : "NOT ";
  38   errs() << "BISECT: " << Status << "running pass "
  39          << "(" << PassNum << ") " << Name << " on " << TargetDesc << "\n";
  40 }
  41
  42 bool OptBisect::shouldRunPass(const Pass *P, StringRef IRDescription) {
  43   assert(BisectEnabled);
  44
  45   return checkPass(P->getPassName(), IRDescription);
  46 }
  47
  48 bool OptBisect::checkPass(const StringRef PassName,
  49                           const StringRef TargetDesc) {
  50   assert(BisectEnabled);
  51
  52   int CurBisectNum = ++LastBisectNum;
  53   bool ShouldRun = (OptBisectLimit == -1 || CurBisectNum <= OptBisectLimit);
  54   printPassMessage(PassName, CurBisectNum, TargetDesc, ShouldRun);
  55   return ShouldRun;
  56 }