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
OptBisect()39 OptBisect::OptBisect() : OptPassGate() {
40 BisectEnabled = OptBisectLimit != std::numeric_limits<int>::max();
41 }
42
printPassMessage(const StringRef & Name,int PassNum,StringRef TargetDesc,bool Running)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
getDescription(const Module & M)50 static std::string getDescription(const Module &M) {
51 return "module (" + M.getName().str() + ")";
52 }
53
getDescription(const Function & F)54 static std::string getDescription(const Function &F) {
55 return "function (" + F.getName().str() + ")";
56 }
57
getDescription(const BasicBlock & BB)58 static std::string getDescription(const BasicBlock &BB) {
59 return "basic block (" + BB.getName().str() + ") in function (" +
60 BB.getParent()->getName().str() + ")";
61 }
62
getDescription(const Loop & L)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
getDescription(const Region & R)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
getDescription(const CallGraphSCC & SCC)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
shouldRunPass(const Pass * P,const Module & U)95 bool OptBisect::shouldRunPass(const Pass *P, const Module &U) {
96 return !BisectEnabled || checkPass(P->getPassName(), getDescription(U));
97 }
98
shouldRunPass(const Pass * P,const Function & U)99 bool OptBisect::shouldRunPass(const Pass *P, const Function &U) {
100 return !BisectEnabled || checkPass(P->getPassName(), getDescription(U));
101 }
102
shouldRunPass(const Pass * P,const BasicBlock & U)103 bool OptBisect::shouldRunPass(const Pass *P, const BasicBlock &U) {
104 return !BisectEnabled || checkPass(P->getPassName(), getDescription(U));
105 }
106
shouldRunPass(const Pass * P,const Region & U)107 bool OptBisect::shouldRunPass(const Pass *P, const Region &U) {
108 return !BisectEnabled || checkPass(P->getPassName(), getDescription(U));
109 }
110
shouldRunPass(const Pass * P,const Loop & U)111 bool OptBisect::shouldRunPass(const Pass *P, const Loop &U) {
112 return !BisectEnabled || checkPass(P->getPassName(), getDescription(U));
113 }
114
shouldRunPass(const Pass * P,const CallGraphSCC & U)115 bool OptBisect::shouldRunPass(const Pass *P, const CallGraphSCC &U) {
116 return !BisectEnabled || checkPass(P->getPassName(), getDescription(U));
117 }
118
checkPass(const StringRef PassName,const StringRef TargetDesc)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 }
128