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/Analysis/CallGraph.h"
  18 #include "llvm/Analysis/CallGraphSCCPass.h"
  19 #include "llvm/Analysis/LoopInfo.h"
  20 #include "llvm/Analysis/RegionInfo.h"
  21 #include "llvm/IR/BasicBlock.h"
  22 #include "llvm/IR/Function.h"
  23 #include "llvm/IR/Module.h"
  24 #include "llvm/Pass.h"
  25 #include "llvm/Support/CommandLine.h"
  26 #include "llvm/Support/raw_ostream.h"
  27 #include <cassert>
  28 #include <limits>
  29 #include <string>
  30
  31 using namespace llvm;
  32
  33 static cl::opt<int> OptBisectLimit("opt-bisect-limit", cl::Hidden,
  34                                    cl::init(std::numeric_limits<int>::max()),
  35                                    cl::Optional,
  36                                    cl::desc("Maximum optimization to perform"));
  37
  38 OptBisect::OptBisect() : OptPassGate() {
  39   BisectEnabled = OptBisectLimit != std::numeric_limits<int>::max();
  40 }
  41
  42 static void printPassMessage(const StringRef &Name, int PassNum,
  43                              StringRef TargetDesc, bool Running) {
  44   StringRef Status = Running ? "" : "NOT ";
  45   errs() << "BISECT: " << Status << "running pass "
  46          << "(" << PassNum << ") " << Name << " on " << TargetDesc << "\n";
  47 }
  48
  49 static std::string getDescription(const Module &M) {
  50   return "module (" + M.getName().str() + ")";
  51 }
  52
  53 static std::string getDescription(const Function &F) {
  54   return "function (" + F.getName().str() + ")";
  55 }
  56
  57 static std::string getDescription(const BasicBlock &BB) {
  58   return "basic block (" + BB.getName().str() + ") in function (" +
  59          BB.getParent()->getName().str() + ")";
  60 }
  61
  62 static std::string getDescription(const Loop &L) {
  63   // FIXME: Move into LoopInfo so we can get a better description
  64   // (and avoid a circular dependency between IR and Analysis).
  65   return "loop";
  66 }
  67
  68 static std::string getDescription(const Region &R) {
  69   // FIXME: Move into RegionInfo so we can get a better description
  70   // (and avoid a circular dependency between IR and Analysis).
  71   return "region";
  72 }
  73
  74 static std::string getDescription(const CallGraphSCC &SCC) {
  75   // FIXME: Move into CallGraphSCCPass to avoid circular dependency between
  76   // IR and Analysis.
  77   std::string Desc = "SCC (";
  78   bool First = true;
  79   for (CallGraphNode *CGN : SCC) {
  80     if (First)
  81       First = false;
  82     else
  83       Desc += ", ";
  84     Function *F = CGN->getFunction();
  85     if (F)
  86       Desc += F->getName();
  87     else
  88       Desc += "<<null function>>";
  89   }
  90   Desc += ")";
  91   return Desc;
  92 }
  93
  94 bool OptBisect::shouldRunPass(const Pass *P, const Module &U) {
  95   return !BisectEnabled || checkPass(P->getPassName(), getDescription(U));
  96 }
  97
  98 bool OptBisect::shouldRunPass(const Pass *P, const Function &U) {
  99   return !BisectEnabled || checkPass(P->getPassName(), getDescription(U));
 100 }
 101
 102 bool OptBisect::shouldRunPass(const Pass *P, const BasicBlock &U) {
 103   return !BisectEnabled || checkPass(P->getPassName(), getDescription(U));
 104 }
 105
 106 bool OptBisect::shouldRunPass(const Pass *P, const Region &U) {
 107   return !BisectEnabled || checkPass(P->getPassName(), getDescription(U));
 108 }
 109
 110 bool OptBisect::shouldRunPass(const Pass *P, const Loop &U) {
 111   return !BisectEnabled || checkPass(P->getPassName(), getDescription(U));
 112 }
 113
 114 bool OptBisect::shouldRunPass(const Pass *P, const CallGraphSCC &U) {
 115   return !BisectEnabled || checkPass(P->getPassName(), getDescription(U));
 116 }
 117
 118 bool OptBisect::checkPass(const StringRef PassName,
 119                           const StringRef TargetDesc) {
 120   assert(BisectEnabled);
 121
 122   int CurBisectNum = ++LastBisectNum;
 123   bool ShouldRun = (OptBisectLimit == -1 || CurBisectNum <= OptBisectLimit);
 124   printPassMessage(PassName, CurBisectNum, TargetDesc, ShouldRun);
 125   return ShouldRun;
 126 }