Argyrios Kyrtzidis | 7196d06 | 2011-06-21 20:20:39 +0000 | [diff] [blame] | 1 | //===--- TransBlockObjCVariable.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 | // rewriteBlockObjCVariable: |
| 11 | // |
| 12 | // Adding __block to an obj-c variable could be either because the the variable |
| 13 | // is used for output storage or the user wanted to break a retain cycle. |
| 14 | // This transformation checks whether a reference of the variable for the block |
| 15 | // is actually needed (it is assigned to or its address is taken) or not. |
| 16 | // If the reference is not needed it will assume __block was added to break a |
| 17 | // cycle so it will remove '__block' and add __weak/__unsafe_unretained. |
| 18 | // e.g |
| 19 | // |
| 20 | // __block Foo *x; |
| 21 | // bar(^ { [x cake]; }); |
| 22 | // ----> |
| 23 | // __weak Foo *x; |
| 24 | // bar(^ { [x cake]; }); |
| 25 | // |
| 26 | //===----------------------------------------------------------------------===// |
| 27 | |
| 28 | #include "Transforms.h" |
| 29 | #include "Internals.h" |
Benjamin Kramer | 471c8b4 | 2012-07-04 20:19:54 +0000 | [diff] [blame] | 30 | #include "clang/AST/ASTContext.h" |
Argyrios Kyrtzidis | 7196d06 | 2011-06-21 20:20:39 +0000 | [diff] [blame] | 31 | #include "clang/Basic/SourceManager.h" |
| 32 | |
| 33 | using namespace clang; |
| 34 | using namespace arcmt; |
| 35 | using namespace trans; |
Argyrios Kyrtzidis | 7196d06 | 2011-06-21 20:20:39 +0000 | [diff] [blame] | 36 | |
| 37 | namespace { |
| 38 | |
| 39 | class RootBlockObjCVarRewriter : |
| 40 | public RecursiveASTVisitor<RootBlockObjCVarRewriter> { |
Argyrios Kyrtzidis | 2a27818 | 2012-03-05 08:46:24 +0000 | [diff] [blame] | 41 | llvm::DenseSet<VarDecl *> &VarsToChange; |
Argyrios Kyrtzidis | 7196d06 | 2011-06-21 20:20:39 +0000 | [diff] [blame] | 42 | |
| 43 | class BlockVarChecker : public RecursiveASTVisitor<BlockVarChecker> { |
| 44 | VarDecl *Var; |
| 45 | |
| 46 | typedef RecursiveASTVisitor<BlockVarChecker> base; |
| 47 | public: |
| 48 | BlockVarChecker(VarDecl *var) : Var(var) { } |
| 49 | |
| 50 | bool TraverseImplicitCastExpr(ImplicitCastExpr *castE) { |
John McCall | f4b88a4 | 2012-03-10 09:33:50 +0000 | [diff] [blame] | 51 | if (DeclRefExpr * |
| 52 | ref = dyn_cast<DeclRefExpr>(castE->getSubExpr())) { |
Argyrios Kyrtzidis | 7196d06 | 2011-06-21 20:20:39 +0000 | [diff] [blame] | 53 | if (ref->getDecl() == Var) { |
| 54 | if (castE->getCastKind() == CK_LValueToRValue) |
| 55 | return true; // Using the value of the variable. |
| 56 | if (castE->getCastKind() == CK_NoOp && castE->isLValue() && |
David Blaikie | 4e4d084 | 2012-03-11 07:00:24 +0000 | [diff] [blame] | 57 | Var->getASTContext().getLangOpts().CPlusPlus) |
Argyrios Kyrtzidis | 7196d06 | 2011-06-21 20:20:39 +0000 | [diff] [blame] | 58 | return true; // Binding to const C++ reference. |
| 59 | } |
| 60 | } |
| 61 | |
| 62 | return base::TraverseImplicitCastExpr(castE); |
| 63 | } |
| 64 | |
John McCall | f4b88a4 | 2012-03-10 09:33:50 +0000 | [diff] [blame] | 65 | bool VisitDeclRefExpr(DeclRefExpr *E) { |
Argyrios Kyrtzidis | 7196d06 | 2011-06-21 20:20:39 +0000 | [diff] [blame] | 66 | if (E->getDecl() == Var) |
| 67 | return false; // The reference of the variable, and not just its value, |
| 68 | // is needed. |
| 69 | return true; |
| 70 | } |
| 71 | }; |
| 72 | |
| 73 | public: |
Benjamin Kramer | facde17 | 2012-06-06 17:32:50 +0000 | [diff] [blame] | 74 | RootBlockObjCVarRewriter(llvm::DenseSet<VarDecl *> &VarsToChange) |
| 75 | : VarsToChange(VarsToChange) { } |
Argyrios Kyrtzidis | 7196d06 | 2011-06-21 20:20:39 +0000 | [diff] [blame] | 76 | |
| 77 | bool VisitBlockDecl(BlockDecl *block) { |
Chris Lattner | 5f9e272 | 2011-07-23 10:55:15 +0000 | [diff] [blame] | 78 | SmallVector<VarDecl *, 4> BlockVars; |
Argyrios Kyrtzidis | 7196d06 | 2011-06-21 20:20:39 +0000 | [diff] [blame] | 79 | |
| 80 | for (BlockDecl::capture_iterator |
| 81 | I = block->capture_begin(), E = block->capture_end(); I != E; ++I) { |
| 82 | VarDecl *var = I->getVariable(); |
| 83 | if (I->isByRef() && |
Argyrios Kyrtzidis | 7196d06 | 2011-06-21 20:20:39 +0000 | [diff] [blame] | 84 | var->getType()->isObjCObjectPointerType() && |
| 85 | isImplicitStrong(var->getType())) { |
| 86 | BlockVars.push_back(var); |
| 87 | } |
| 88 | } |
| 89 | |
| 90 | for (unsigned i = 0, e = BlockVars.size(); i != e; ++i) { |
| 91 | VarDecl *var = BlockVars[i]; |
Argyrios Kyrtzidis | 7196d06 | 2011-06-21 20:20:39 +0000 | [diff] [blame] | 92 | |
| 93 | BlockVarChecker checker(var); |
| 94 | bool onlyValueOfVarIsNeeded = checker.TraverseStmt(block->getBody()); |
Argyrios Kyrtzidis | 2a27818 | 2012-03-05 08:46:24 +0000 | [diff] [blame] | 95 | if (onlyValueOfVarIsNeeded) |
| 96 | VarsToChange.insert(var); |
| 97 | else |
| 98 | VarsToChange.erase(var); |
Argyrios Kyrtzidis | 7196d06 | 2011-06-21 20:20:39 +0000 | [diff] [blame] | 99 | } |
| 100 | |
| 101 | return true; |
| 102 | } |
| 103 | |
| 104 | private: |
Argyrios Kyrtzidis | 7196d06 | 2011-06-21 20:20:39 +0000 | [diff] [blame] | 105 | bool isImplicitStrong(QualType ty) { |
| 106 | if (isa<AttributedType>(ty.getTypePtr())) |
| 107 | return false; |
| 108 | return ty.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong; |
| 109 | } |
| 110 | }; |
| 111 | |
| 112 | class BlockObjCVarRewriter : public RecursiveASTVisitor<BlockObjCVarRewriter> { |
Argyrios Kyrtzidis | 2a27818 | 2012-03-05 08:46:24 +0000 | [diff] [blame] | 113 | llvm::DenseSet<VarDecl *> &VarsToChange; |
Argyrios Kyrtzidis | 7196d06 | 2011-06-21 20:20:39 +0000 | [diff] [blame] | 114 | |
| 115 | public: |
Benjamin Kramer | 1ada2a6 | 2012-06-06 20:15:08 +0000 | [diff] [blame] | 116 | BlockObjCVarRewriter(llvm::DenseSet<VarDecl *> &VarsToChange) |
| 117 | : VarsToChange(VarsToChange) { } |
Argyrios Kyrtzidis | 7196d06 | 2011-06-21 20:20:39 +0000 | [diff] [blame] | 118 | |
| 119 | bool TraverseBlockDecl(BlockDecl *block) { |
Benjamin Kramer | facde17 | 2012-06-06 17:32:50 +0000 | [diff] [blame] | 120 | RootBlockObjCVarRewriter(VarsToChange).TraverseDecl(block); |
Argyrios Kyrtzidis | 7196d06 | 2011-06-21 20:20:39 +0000 | [diff] [blame] | 121 | return true; |
| 122 | } |
| 123 | }; |
| 124 | |
| 125 | } // anonymous namespace |
| 126 | |
Argyrios Kyrtzidis | 2a27818 | 2012-03-05 08:46:24 +0000 | [diff] [blame] | 127 | void BlockObjCVariableTraverser::traverseBody(BodyContext &BodyCtx) { |
| 128 | MigrationPass &Pass = BodyCtx.getMigrationContext().Pass; |
| 129 | llvm::DenseSet<VarDecl *> VarsToChange; |
| 130 | |
Benjamin Kramer | 1ada2a6 | 2012-06-06 20:15:08 +0000 | [diff] [blame] | 131 | BlockObjCVarRewriter trans(VarsToChange); |
Argyrios Kyrtzidis | 2a27818 | 2012-03-05 08:46:24 +0000 | [diff] [blame] | 132 | trans.TraverseStmt(BodyCtx.getTopStmt()); |
| 133 | |
| 134 | for (llvm::DenseSet<VarDecl *>::iterator |
| 135 | I = VarsToChange.begin(), E = VarsToChange.end(); I != E; ++I) { |
| 136 | VarDecl *var = *I; |
| 137 | BlocksAttr *attr = var->getAttr<BlocksAttr>(); |
| 138 | if(!attr) |
| 139 | continue; |
| 140 | bool useWeak = canApplyWeak(Pass.Ctx, var->getType()); |
| 141 | SourceManager &SM = Pass.Ctx.getSourceManager(); |
| 142 | Transaction Trans(Pass.TA); |
| 143 | Pass.TA.replaceText(SM.getExpansionLoc(attr->getLocation()), |
| 144 | "__block", |
| 145 | useWeak ? "__weak" : "__unsafe_unretained"); |
| 146 | } |
Argyrios Kyrtzidis | 7196d06 | 2011-06-21 20:20:39 +0000 | [diff] [blame] | 147 | } |