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annotate lib/Transforms/IPO/PruneEH.cpp @ 83:60c9769439b8

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LLVM 3.7
author Tatsuki IHA <e125716@ie.u-ryukyu.ac.jp>
date Wed, 18 Feb 2015 14:55:36 +0900
parents 54457678186b
children afa8332a0e37
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1 //===- PruneEH.cpp - Pass which deletes unused exception handlers ---------===//
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2 //
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3 // The LLVM Compiler Infrastructure
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4 //
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5 // This file is distributed under the University of Illinois Open Source
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6 // License. See LICENSE.TXT for details.
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7 //
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8 //===----------------------------------------------------------------------===//
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9 //
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10 // This file implements a simple interprocedural pass which walks the
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11 // call-graph, turning invoke instructions into calls, iff the callee cannot
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12 // throw an exception, and marking functions 'nounwind' if they cannot throw.
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13 // It implements this as a bottom-up traversal of the call-graph.
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14 //
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15 //===----------------------------------------------------------------------===//
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16
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17 #include "llvm/Transforms/IPO.h"
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18 #include "llvm/ADT/SmallPtrSet.h"
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19 #include "llvm/ADT/SmallVector.h"
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20 #include "llvm/ADT/Statistic.h"
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21 #include "llvm/Support/raw_ostream.h"
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22 #include "llvm/Analysis/CallGraph.h"
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23 #include "llvm/Analysis/CallGraphSCCPass.h"
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24 #include "llvm/Analysis/LibCallSemantics.h"
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25 #include "llvm/IR/CFG.h"
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26 #include "llvm/IR/Constants.h"
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27 #include "llvm/IR/Function.h"
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28 #include "llvm/IR/Instructions.h"
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29 #include "llvm/IR/IntrinsicInst.h"
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30 #include "llvm/IR/LLVMContext.h"
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31 #include <algorithm>
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32 using namespace llvm;
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33
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34 #define DEBUG_TYPE "prune-eh"
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35
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36 STATISTIC(NumRemoved, "Number of invokes removed");
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37 STATISTIC(NumUnreach, "Number of noreturn calls optimized");
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38
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39 namespace {
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40 struct PruneEH : public CallGraphSCCPass {
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41 static char ID; // Pass identification, replacement for typeid
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42 PruneEH() : CallGraphSCCPass(ID) {
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43 initializePruneEHPass(*PassRegistry::getPassRegistry());
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44 }
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45
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46 // runOnSCC - Analyze the SCC, performing the transformation if possible.
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47 bool runOnSCC(CallGraphSCC &SCC) override;
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48
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49 bool SimplifyFunction(Function *F);
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50 void DeleteBasicBlock(BasicBlock *BB);
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51 };
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52 }
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53
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54 char PruneEH::ID = 0;
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55 INITIALIZE_PASS_BEGIN(PruneEH, "prune-eh",
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56 "Remove unused exception handling info", false, false)
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57 INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
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58 INITIALIZE_PASS_END(PruneEH, "prune-eh",
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59 "Remove unused exception handling info", false, false)
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60
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61 Pass *llvm::createPruneEHPass() { return new PruneEH(); }
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62
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63
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64 bool PruneEH::runOnSCC(CallGraphSCC &SCC) {
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65 SmallPtrSet<CallGraphNode *, 8> SCCNodes;
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66 CallGraph &CG = getAnalysis<CallGraphWrapperPass>().getCallGraph();
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67 bool MadeChange = false;
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68
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69 // Fill SCCNodes with the elements of the SCC. Used for quickly
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70 // looking up whether a given CallGraphNode is in this SCC.
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71 for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I)
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72 SCCNodes.insert(*I);
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73
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74 // First pass, scan all of the functions in the SCC, simplifying them
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75 // according to what we know.
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76 for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I)
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77 if (Function *F = (*I)->getFunction())
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78 MadeChange |= SimplifyFunction(F);
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79
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80 // Next, check to see if any callees might throw or if there are any external
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81 // functions in this SCC: if so, we cannot prune any functions in this SCC.
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82 // Definitions that are weak and not declared non-throwing might be
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83 // overridden at linktime with something that throws, so assume that.
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84 // If this SCC includes the unwind instruction, we KNOW it throws, so
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85 // obviously the SCC might throw.
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86 //
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87 bool SCCMightUnwind = false, SCCMightReturn = false;
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88 for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end();
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89 (!SCCMightUnwind || !SCCMightReturn) && I != E; ++I) {
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90 Function *F = (*I)->getFunction();
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91 if (!F) {
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92 SCCMightUnwind = true;
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93 SCCMightReturn = true;
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94 } else if (F->isDeclaration() || F->mayBeOverridden()) {
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95 SCCMightUnwind |= !F->doesNotThrow();
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96 SCCMightReturn |= !F->doesNotReturn();
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97 } else {
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98 bool CheckUnwind = !SCCMightUnwind && !F->doesNotThrow();
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99 bool CheckReturn = !SCCMightReturn && !F->doesNotReturn();
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100
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101 if (!CheckUnwind && !CheckReturn)
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102 continue;
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103
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104 // Check to see if this function performs an unwind or calls an
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105 // unwinding function.
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106 for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
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107 if (CheckUnwind && isa<ResumeInst>(BB->getTerminator())) {
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108 // Uses unwind / resume!
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109 SCCMightUnwind = true;
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110 } else if (CheckReturn && isa<ReturnInst>(BB->getTerminator())) {
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111 SCCMightReturn = true;
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112 }
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113
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114 // Invoke instructions don't allow unwinding to continue, so we are
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115 // only interested in call instructions.
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116 if (CheckUnwind && !SCCMightUnwind)
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117 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
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118 if (CallInst *CI = dyn_cast<CallInst>(I)) {
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119 if (CI->doesNotThrow()) {
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120 // This call cannot throw.
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121 } else if (Function *Callee = CI->getCalledFunction()) {
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122 CallGraphNode *CalleeNode = CG[Callee];
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123 // If the callee is outside our current SCC then we may
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124 // throw because it might.
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125 if (!SCCNodes.count(CalleeNode)) {
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parents:
diff changeset
126 SCCMightUnwind = true;
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
127 break;
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
128 }
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
129 } else {
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
130 // Indirect call, it might throw.
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
131 SCCMightUnwind = true;
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
132 break;
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
133 }
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
134 }
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
135 if (SCCMightUnwind && SCCMightReturn) break;
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
136 }
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
137 }
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
138 }
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
139
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
140 // If the SCC doesn't unwind or doesn't throw, note this fact.
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
141 if (!SCCMightUnwind || !SCCMightReturn)
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
142 for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
143 AttrBuilder NewAttributes;
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
144
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
145 if (!SCCMightUnwind)
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
146 NewAttributes.addAttribute(Attribute::NoUnwind);
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
147 if (!SCCMightReturn)
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
148 NewAttributes.addAttribute(Attribute::NoReturn);
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
149
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
150 Function *F = (*I)->getFunction();
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
151 const AttributeSet &PAL = F->getAttributes().getFnAttributes();
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
152 const AttributeSet &NPAL = AttributeSet::get(
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
153 F->getContext(), AttributeSet::FunctionIndex, NewAttributes);
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
154
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
155 if (PAL != NPAL) {
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
156 MadeChange = true;
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
157 F->addAttributes(AttributeSet::FunctionIndex, NPAL);
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
158 }
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
159 }
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
160
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
161 for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
162 // Convert any invoke instructions to non-throwing functions in this node
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
163 // into call instructions with a branch. This makes the exception blocks
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
164 // dead.
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
165 if (Function *F = (*I)->getFunction())
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
166 MadeChange |= SimplifyFunction(F);
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
167 }
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
168
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
169 return MadeChange;
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
170 }
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
171
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
172
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
173 // SimplifyFunction - Given information about callees, simplify the specified
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
174 // function if we have invokes to non-unwinding functions or code after calls to
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
175 // no-return functions.
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
176 bool PruneEH::SimplifyFunction(Function *F) {
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
177 bool MadeChange = false;
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
178 for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
179 if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator()))
83
60c9769439b8 LLVM 3.7
Tatsuki IHA <e125716@ie.u-ryukyu.ac.jp>
parents: 77
diff changeset
180 if (II->doesNotThrow() && canSimplifyInvokeNoUnwind(II)) {
0
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
181 SmallVector<Value*, 8> Args(II->op_begin(), II->op_end() - 3);
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
182 // Insert a call instruction before the invoke.
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
183 CallInst *Call = CallInst::Create(II->getCalledValue(), Args, "", II);
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
184 Call->takeName(II);
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
185 Call->setCallingConv(II->getCallingConv());
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
186 Call->setAttributes(II->getAttributes());
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
187 Call->setDebugLoc(II->getDebugLoc());
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
188
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
189 // Anything that used the value produced by the invoke instruction
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
190 // now uses the value produced by the call instruction. Note that we
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
191 // do this even for void functions and calls with no uses so that the
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
192 // callgraph edge is updated.
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
193 II->replaceAllUsesWith(Call);
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
194 BasicBlock *UnwindBlock = II->getUnwindDest();
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
195 UnwindBlock->removePredecessor(II->getParent());
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
196
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
197 // Insert a branch to the normal destination right before the
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
198 // invoke.
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
199 BranchInst::Create(II->getNormalDest(), II);
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
200
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
201 // Finally, delete the invoke instruction!
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
202 BB->getInstList().pop_back();
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
203
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
204 // If the unwind block is now dead, nuke it.
83
60c9769439b8 LLVM 3.7
Tatsuki IHA <e125716@ie.u-ryukyu.ac.jp>
parents: 77
diff changeset
205 if (pred_empty(UnwindBlock))
0
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
206 DeleteBasicBlock(UnwindBlock); // Delete the new BB.
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
207
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
208 ++NumRemoved;
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
209 MadeChange = true;
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
210 }
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
211
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
212 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; )
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
213 if (CallInst *CI = dyn_cast<CallInst>(I++))
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
214 if (CI->doesNotReturn() && !isa<UnreachableInst>(I)) {
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
215 // This call calls a function that cannot return. Insert an
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
216 // unreachable instruction after it and simplify the code. Do this
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
217 // by splitting the BB, adding the unreachable, then deleting the
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
218 // new BB.
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
219 BasicBlock *New = BB->splitBasicBlock(I);
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
220
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
221 // Remove the uncond branch and add an unreachable.
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
222 BB->getInstList().pop_back();
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
223 new UnreachableInst(BB->getContext(), BB);
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
224
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
225 DeleteBasicBlock(New); // Delete the new BB.
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
226 MadeChange = true;
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
227 ++NumUnreach;
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
228 break;
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
229 }
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
230 }
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
231
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
232 return MadeChange;
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
233 }
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
234
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
235 /// DeleteBasicBlock - remove the specified basic block from the program,
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
236 /// updating the callgraph to reflect any now-obsolete edges due to calls that
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
237 /// exist in the BB.
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
238 void PruneEH::DeleteBasicBlock(BasicBlock *BB) {
83
60c9769439b8 LLVM 3.7
Tatsuki IHA <e125716@ie.u-ryukyu.ac.jp>
parents: 77
diff changeset
239 assert(pred_empty(BB) && "BB is not dead!");
33
e4204d083e25 LLVM 3.5
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents: 0
diff changeset
240 CallGraph &CG = getAnalysis<CallGraphWrapperPass>().getCallGraph();
0
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
241
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
242 CallGraphNode *CGN = CG[BB->getParent()];
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
243 for (BasicBlock::iterator I = BB->end(), E = BB->begin(); I != E; ) {
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
244 --I;
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
245 if (CallInst *CI = dyn_cast<CallInst>(I)) {
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
246 if (!isa<IntrinsicInst>(I))
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
247 CGN->removeCallEdgeFor(CI);
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
248 } else if (InvokeInst *II = dyn_cast<InvokeInst>(I))
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
249 CGN->removeCallEdgeFor(II);
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
250 if (!I->use_empty())
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
251 I->replaceAllUsesWith(UndefValue::get(I->getType()));
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
252 }
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
253
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
254 // Get the list of successors of this block.
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
255 std::vector<BasicBlock*> Succs(succ_begin(BB), succ_end(BB));
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
256
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
257 for (unsigned i = 0, e = Succs.size(); i != e; ++i)
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
258 Succs[i]->removePredecessor(BB);
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
259
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
260 BB->eraseFromParent();
95c75e76d11b LLVM 3.4
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff changeset
261 }