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/Analysis/CallGraphSCCPass.h"
17#include "llvm/Analysis/LazyCallGraph.h"
18#include "llvm/Analysis/LoopInfo.h"
19#include "llvm/IR/Module.h"
20#include "llvm/IR/OptBisect.h"
21#include "llvm/Pass.h"
22#include "llvm/Support/CommandLine.h"
23#include "llvm/Support/raw_ostream.h"
24
25using namespace llvm;
26
27static cl::opt<int> OptBisectLimit("opt-bisect-limit", cl::Hidden,
28                                   cl::init(INT_MAX), cl::Optional,
29                                   cl::desc("Maximum optimization to perform"));
30
31OptBisect::OptBisect() {
32  BisectEnabled = OptBisectLimit != INT_MAX;
33}
34
35static 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
42static void printCaseMessage(int CaseNum, StringRef Msg, bool Running) {
43  if (Running)
44    errs() << "BISECT: running case (";
45  else
46    errs() << "BISECT: NOT running case (";
47  errs() << CaseNum << "): " << Msg << "\n";
48}
49
50static std::string getDescription(const Module &M) {
51  return "module (" + M.getName().str() + ")";
52}
53
54static std::string getDescription(const Function &F) {
55  return "function (" + F.getName().str() + ")";
56}
57
58static std::string getDescription(const BasicBlock &BB) {
59  return "basic block (" + BB.getName().str() + ") in function (" +
60         BB.getParent()->getName().str() + ")";
61}
62
63static std::string getDescription(const Loop &L) {
64  // FIXME: I'd like to be able to provide a better description here, but
65  //        calling L->getHeader() would introduce a new dependency on the
66  //        LLVMCore library.
67  return "loop";
68}
69
70static std::string getDescription(const CallGraphSCC &SCC) {
71  std::string Desc = "SCC (";
72  bool First = true;
73  for (CallGraphNode *CGN : SCC) {
74    if (First)
75      First = false;
76    else
77      Desc += ", ";
78    Function *F = CGN->getFunction();
79    if (F)
80      Desc += F->getName();
81    else
82      Desc += "<<null function>>";
83  }
84  Desc += ")";
85  return Desc;
86}
87
88// Force instantiations.
89template bool OptBisect::shouldRunPass(const Pass *, const Module &);
90template bool OptBisect::shouldRunPass(const Pass *, const Function &);
91template bool OptBisect::shouldRunPass(const Pass *, const BasicBlock &);
92template bool OptBisect::shouldRunPass(const Pass *, const Loop &);
93template bool OptBisect::shouldRunPass(const Pass *, const CallGraphSCC &);
94
95template <class UnitT>
96bool OptBisect::shouldRunPass(const Pass *P, const UnitT &U) {
97  if (!BisectEnabled)
98    return true;
99  return checkPass(P->getPassName(), getDescription(U));
100}
101
102bool OptBisect::checkPass(const StringRef PassName,
103                          const StringRef TargetDesc) {
104  assert(BisectEnabled);
105
106  int CurBisectNum = ++LastBisectNum;
107  bool ShouldRun = (OptBisectLimit == -1 || CurBisectNum <= OptBisectLimit);
108  printPassMessage(PassName, CurBisectNum, TargetDesc, ShouldRun);
109  return ShouldRun;
110}
111
112bool OptBisect::shouldRunCase(const Twine &Msg) {
113  if (!BisectEnabled)
114    return true;
115  int CurFuelNum = ++LastBisectNum;
116  bool ShouldRun = (OptBisectLimit == -1 || CurFuelNum <= OptBisectLimit);
117  printCaseMessage(CurFuelNum, Msg.str(), ShouldRun);
118  return ShouldRun;
119}
120
121