Argyrios Kyrtzidis | 7196d06 | 2011-06-21 20:20:39 +0000 | [diff] [blame^] | 1 | //===--- TransEmptyStatements.cpp - Tranformations to ARC mode ------------===// |
| 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 | // removeEmptyStatements: |
| 11 | // |
| 12 | // Removes empty statements that are leftovers from previous transformations. |
| 13 | // e.g for |
| 14 | // |
| 15 | // [x retain]; |
| 16 | // |
| 17 | // removeRetainReleaseDealloc will leave an empty ";" that removeEmptyStatements |
| 18 | // will remove. |
| 19 | // |
| 20 | //===----------------------------------------------------------------------===// |
| 21 | |
| 22 | #include "Transforms.h" |
| 23 | #include "Internals.h" |
| 24 | #include "clang/AST/StmtVisitor.h" |
| 25 | |
| 26 | using namespace clang; |
| 27 | using namespace arcmt; |
| 28 | using namespace trans; |
| 29 | using llvm::StringRef; |
| 30 | |
| 31 | namespace { |
| 32 | |
| 33 | class EmptyStatementsRemover : |
| 34 | public RecursiveASTVisitor<EmptyStatementsRemover> { |
| 35 | MigrationPass &Pass; |
| 36 | llvm::DenseSet<unsigned> MacroLocs; |
| 37 | |
| 38 | public: |
| 39 | EmptyStatementsRemover(MigrationPass &pass) : Pass(pass) { |
| 40 | for (unsigned i = 0, e = Pass.ARCMTMacroLocs.size(); i != e; ++i) |
| 41 | MacroLocs.insert(Pass.ARCMTMacroLocs[i].getRawEncoding()); |
| 42 | } |
| 43 | |
| 44 | bool TraverseStmtExpr(StmtExpr *E) { |
| 45 | CompoundStmt *S = E->getSubStmt(); |
| 46 | for (CompoundStmt::body_iterator |
| 47 | I = S->body_begin(), E = S->body_end(); I != E; ++I) { |
| 48 | if (I != E - 1) |
| 49 | check(*I); |
| 50 | TraverseStmt(*I); |
| 51 | } |
| 52 | return true; |
| 53 | } |
| 54 | |
| 55 | bool VisitCompoundStmt(CompoundStmt *S) { |
| 56 | for (CompoundStmt::body_iterator |
| 57 | I = S->body_begin(), E = S->body_end(); I != E; ++I) |
| 58 | check(*I); |
| 59 | return true; |
| 60 | } |
| 61 | |
| 62 | bool isMacroLoc(SourceLocation loc) { |
| 63 | if (loc.isInvalid()) return false; |
| 64 | return MacroLocs.count(loc.getRawEncoding()); |
| 65 | } |
| 66 | |
| 67 | ASTContext &getContext() { return Pass.Ctx; } |
| 68 | |
| 69 | private: |
| 70 | /// \brief Returns true if the statement became empty due to previous |
| 71 | /// transformations. |
| 72 | class EmptyChecker : public StmtVisitor<EmptyChecker, bool> { |
| 73 | EmptyStatementsRemover &Trans; |
| 74 | |
| 75 | public: |
| 76 | EmptyChecker(EmptyStatementsRemover &trans) : Trans(trans) { } |
| 77 | |
| 78 | bool VisitNullStmt(NullStmt *S) { |
| 79 | return Trans.isMacroLoc(S->getLeadingEmptyMacroLoc()); |
| 80 | } |
| 81 | bool VisitCompoundStmt(CompoundStmt *S) { |
| 82 | if (S->body_empty()) |
| 83 | return false; // was already empty, not because of transformations. |
| 84 | for (CompoundStmt::body_iterator |
| 85 | I = S->body_begin(), E = S->body_end(); I != E; ++I) |
| 86 | if (!Visit(*I)) |
| 87 | return false; |
| 88 | return true; |
| 89 | } |
| 90 | bool VisitIfStmt(IfStmt *S) { |
| 91 | if (S->getConditionVariable()) |
| 92 | return false; |
| 93 | Expr *condE = S->getCond(); |
| 94 | if (!condE) |
| 95 | return false; |
| 96 | if (hasSideEffects(condE, Trans.getContext())) |
| 97 | return false; |
| 98 | if (!S->getThen() || !Visit(S->getThen())) |
| 99 | return false; |
| 100 | if (S->getElse() && !Visit(S->getElse())) |
| 101 | return false; |
| 102 | return true; |
| 103 | } |
| 104 | bool VisitWhileStmt(WhileStmt *S) { |
| 105 | if (S->getConditionVariable()) |
| 106 | return false; |
| 107 | Expr *condE = S->getCond(); |
| 108 | if (!condE) |
| 109 | return false; |
| 110 | if (hasSideEffects(condE, Trans.getContext())) |
| 111 | return false; |
| 112 | if (!S->getBody()) |
| 113 | return false; |
| 114 | return Visit(S->getBody()); |
| 115 | } |
| 116 | bool VisitDoStmt(DoStmt *S) { |
| 117 | Expr *condE = S->getCond(); |
| 118 | if (!condE) |
| 119 | return false; |
| 120 | if (hasSideEffects(condE, Trans.getContext())) |
| 121 | return false; |
| 122 | if (!S->getBody()) |
| 123 | return false; |
| 124 | return Visit(S->getBody()); |
| 125 | } |
| 126 | bool VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) { |
| 127 | Expr *Exp = S->getCollection(); |
| 128 | if (!Exp) |
| 129 | return false; |
| 130 | if (hasSideEffects(Exp, Trans.getContext())) |
| 131 | return false; |
| 132 | if (!S->getBody()) |
| 133 | return false; |
| 134 | return Visit(S->getBody()); |
| 135 | } |
| 136 | bool VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) { |
| 137 | if (!S->getSubStmt()) |
| 138 | return false; |
| 139 | return Visit(S->getSubStmt()); |
| 140 | } |
| 141 | }; |
| 142 | |
| 143 | void check(Stmt *S) { |
| 144 | if (!S) return; |
| 145 | if (EmptyChecker(*this).Visit(S)) { |
| 146 | Transaction Trans(Pass.TA); |
| 147 | Pass.TA.removeStmt(S); |
| 148 | } |
| 149 | } |
| 150 | }; |
| 151 | |
| 152 | } // anonymous namespace |
| 153 | |
| 154 | void trans::removeEmptyStatements(MigrationPass &pass) { |
| 155 | EmptyStatementsRemover(pass).TraverseDecl(pass.Ctx.getTranslationUnitDecl()); |
| 156 | |
| 157 | for (unsigned i = 0, e = pass.ARCMTMacroLocs.size(); i != e; ++i) { |
| 158 | Transaction Trans(pass.TA); |
| 159 | pass.TA.remove(pass.ARCMTMacroLocs[i]); |
| 160 | } |
| 161 | } |