lib/IR/OptBisect.cpp

   1 //===- llvm/IR/OptBisect/Bisect.cpp - LLVM Bisect support -----------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 /// \file
  11 /// This file implements support for a bisecting optimizations based on a
  12 /// command line option.
  13 //
  14 //===----------------------------------------------------------------------===//
  15
  16 #include "llvm/IR/OptBisect.h"
  17 #include "llvm/ADT/StringRef.h"
  18 #include "llvm/Analysis/CallGraph.h"
  19 #include "llvm/Analysis/CallGraphSCCPass.h"
  20 #include "llvm/Analysis/LoopInfo.h"
  21 #include "llvm/Analysis/RegionInfo.h"
  22 #include "llvm/IR/BasicBlock.h"
  23 #include "llvm/IR/Function.h"
  24 #include "llvm/IR/Module.h"
  25 #include "llvm/Pass.h"
  26 #include "llvm/Support/CommandLine.h"
  27 #include "llvm/Support/raw_ostream.h"
  28 #include <cassert>
  29 #include <limits>
  30 #include <string>
  31
  32 using namespace llvm;
  33
  34 static cl::opt<int> OptBisectLimit("opt-bisect-limit", cl::Hidden,
  35                                    cl::init(std::numeric_limits<int>::max()),
  36                                    cl::Optional,
  37                                    cl::desc("Maximum optimization to perform"));
  38
  39 OptBisect::OptBisect() : OptPassGate() {
  40   BisectEnabled = OptBisectLimit != std::numeric_limits<int>::max();
  41 }
  42
  43 static void printPassMessage(const StringRef &Name, int PassNum,
  44                              StringRef TargetDesc, bool Running) {
  45   StringRef Status = Running ? "" : "NOT ";
  46   errs() << "BISECT: " << Status << "running pass "
  47          << "(" << PassNum << ") " << Name << " on " << TargetDesc << "\n";
  48 }
  49
  50 static std::string getDescription(const Module &M) {
  51   return "module (" + M.getName().str() + ")";
  52 }
  53
  54 static std::string getDescription(const Function &F) {
  55   return "function (" + F.getName().str() + ")";
  56 }
  57
  58 static std::string getDescription(const BasicBlock &BB) {
  59   return "basic block (" + BB.getName().str() + ") in function (" +
  60          BB.getParent()->getName().str() + ")";
  61 }
  62
  63 static std::string getDescription(const Loop &L) {
  64   // FIXME: Move into LoopInfo so we can get a better description
  65   // (and avoid a circular dependency between IR and Analysis).
  66   return "loop";
  67 }
  68
  69 static std::string getDescription(const Region &R) {
  70   // FIXME: Move into RegionInfo so we can get a better description
  71   // (and avoid a circular dependency between IR and Analysis).
  72   return "region";
  73 }
  74
  75 static std::string getDescription(const CallGraphSCC &SCC) {
  76   // FIXME: Move into CallGraphSCCPass to avoid circular dependency between
  77   // IR and Analysis.
  78   std::string Desc = "SCC (";
  79   bool First = true;
  80   for (CallGraphNode *CGN : SCC) {
  81     if (First)
  82       First = false;
  83     else
  84       Desc += ", ";
  85     Function *F = CGN->getFunction();
  86     if (F)
  87       Desc += F->getName();
  88     else
  89       Desc += "<<null function>>";
  90   }
  91   Desc += ")";
  92   return Desc;
  93 }
  94
  95 bool OptBisect::shouldRunPass(const Pass *P, const Module &U) {
  96   return !BisectEnabled || checkPass(P->getPassName(), getDescription(U));
  97 }
  98
  99 bool OptBisect::shouldRunPass(const Pass *P, const Function &U) {
 100   return !BisectEnabled || checkPass(P->getPassName(), getDescription(U));
 101 }
 102
 103 bool OptBisect::shouldRunPass(const Pass *P, const BasicBlock &U) {
 104   return !BisectEnabled || checkPass(P->getPassName(), getDescription(U));
 105 }
 106
 107 bool OptBisect::shouldRunPass(const Pass *P, const Region &U) {
 108   return !BisectEnabled || checkPass(P->getPassName(), getDescription(U));
 109 }
 110
 111 bool OptBisect::shouldRunPass(const Pass *P, const Loop &U) {
 112   return !BisectEnabled || checkPass(P->getPassName(), getDescription(U));
 113 }
 114
 115 bool OptBisect::shouldRunPass(const Pass *P, const CallGraphSCC &U) {
 116   return !BisectEnabled || checkPass(P->getPassName(), getDescription(U));
 117 }
 118
 119 bool OptBisect::checkPass(const StringRef PassName,
 120                           const StringRef TargetDesc) {
 121   assert(BisectEnabled);
 122
 123   int CurBisectNum = ++LastBisectNum;
 124   bool ShouldRun = (OptBisectLimit == -1 || CurBisectNum <= OptBisectLimit);
 125   printPassMessage(PassName, CurBisectNum, TargetDesc, ShouldRun);
 126   return ShouldRun;
 127 }