1 //===-- Transforms.h - Transformations to ARC mode --------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef LLVM_CLANG_LIB_ARCMIGRATE_TRANSFORMS_H
10 #define LLVM_CLANG_LIB_ARCMIGRATE_TRANSFORMS_H
11 
12 #include "clang/AST/ParentMap.h"
13 #include "clang/AST/RecursiveASTVisitor.h"
14 #include "llvm/ADT/DenseSet.h"
15 #include "llvm/Support/SaveAndRestore.h"
16 
17 namespace clang {
18   class Decl;
19   class Stmt;
20   class BlockDecl;
21   class ObjCMethodDecl;
22   class FunctionDecl;
23 
24 namespace arcmt {
25   class MigrationPass;
26 
27 namespace trans {
28 
29   class MigrationContext;
30 
31 //===----------------------------------------------------------------------===//
32 // Transformations.
33 //===----------------------------------------------------------------------===//
34 
35 void rewriteAutoreleasePool(MigrationPass &pass);
36 void rewriteUnbridgedCasts(MigrationPass &pass);
37 void makeAssignARCSafe(MigrationPass &pass);
38 void removeRetainReleaseDeallocFinalize(MigrationPass &pass);
39 void removeZeroOutPropsInDeallocFinalize(MigrationPass &pass);
40 void rewriteUnusedInitDelegate(MigrationPass &pass);
41 void checkAPIUses(MigrationPass &pass);
42 
43 void removeEmptyStatementsAndDeallocFinalize(MigrationPass &pass);
44 
45 class BodyContext {
46   MigrationContext &MigrateCtx;
47   ParentMap PMap;
48   Stmt *TopStmt;
49 
50 public:
51   BodyContext(MigrationContext &MigrateCtx, Stmt *S)
52     : MigrateCtx(MigrateCtx), PMap(S), TopStmt(S) {}
53 
54   MigrationContext &getMigrationContext() { return MigrateCtx; }
55   ParentMap &getParentMap() { return PMap; }
56   Stmt *getTopStmt() { return TopStmt; }
57 };
58 
59 class ObjCImplementationContext {
60   MigrationContext &MigrateCtx;
61   ObjCImplementationDecl *ImpD;
62 
63 public:
64   ObjCImplementationContext(MigrationContext &MigrateCtx,
65                             ObjCImplementationDecl *D)
66     : MigrateCtx(MigrateCtx), ImpD(D) {}
67 
68   MigrationContext &getMigrationContext() { return MigrateCtx; }
69   ObjCImplementationDecl *getImplementationDecl() { return ImpD; }
70 };
71 
72 class ASTTraverser {
73 public:
74   virtual ~ASTTraverser();
75   virtual void traverseTU(MigrationContext &MigrateCtx) { }
76   virtual void traverseBody(BodyContext &BodyCtx) { }
77   virtual void traverseObjCImplementation(ObjCImplementationContext &ImplCtx) {}
78 };
79 
80 class MigrationContext {
81   std::vector<ASTTraverser *> Traversers;
82 
83 public:
84   MigrationPass &Pass;
85 
86   struct GCAttrOccurrence {
87     enum AttrKind { Weak, Strong } Kind;
88     SourceLocation Loc;
89     QualType ModifiedType;
90     Decl *Dcl;
91     /// true if the attribute is owned, e.g. it is in a body and not just
92     /// in an interface.
93     bool FullyMigratable;
94   };
95   std::vector<GCAttrOccurrence> GCAttrs;
96   llvm::DenseSet<SourceLocation> AttrSet;
97   llvm::DenseSet<SourceLocation> RemovedAttrSet;
98 
99   /// Set of raw '@' locations for 'assign' properties group that contain
100   /// GC __weak.
101   llvm::DenseSet<SourceLocation> AtPropsWeak;
102 
103   explicit MigrationContext(MigrationPass &pass) : Pass(pass) {}
104   ~MigrationContext();
105 
106   typedef std::vector<ASTTraverser *>::iterator traverser_iterator;
107   traverser_iterator traversers_begin() { return Traversers.begin(); }
108   traverser_iterator traversers_end() { return Traversers.end(); }
109 
110   void addTraverser(ASTTraverser *traverser) {
111     Traversers.push_back(traverser);
112   }
113 
114   bool isGCOwnedNonObjC(QualType T);
115   bool removePropertyAttribute(StringRef fromAttr, SourceLocation atLoc) {
116     return rewritePropertyAttribute(fromAttr, StringRef(), atLoc);
117   }
118   bool rewritePropertyAttribute(StringRef fromAttr, StringRef toAttr,
119                                 SourceLocation atLoc);
120   bool addPropertyAttribute(StringRef attr, SourceLocation atLoc);
121 
122   void traverse(TranslationUnitDecl *TU);
123 
124   void dumpGCAttrs();
125 };
126 
127 class PropertyRewriteTraverser : public ASTTraverser {
128 public:
129   void traverseObjCImplementation(ObjCImplementationContext &ImplCtx) override;
130 };
131 
132 class BlockObjCVariableTraverser : public ASTTraverser {
133 public:
134   void traverseBody(BodyContext &BodyCtx) override;
135 };
136 
137 class ProtectedScopeTraverser : public ASTTraverser {
138 public:
139   void traverseBody(BodyContext &BodyCtx) override;
140 };
141 
142 // GC transformations
143 
144 class GCAttrsTraverser : public ASTTraverser {
145 public:
146   void traverseTU(MigrationContext &MigrateCtx) override;
147 };
148 
149 class GCCollectableCallsTraverser : public ASTTraverser {
150 public:
151   void traverseBody(BodyContext &BodyCtx) override;
152 };
153 
154 //===----------------------------------------------------------------------===//
155 // Helpers.
156 //===----------------------------------------------------------------------===//
157 
158 /// Determine whether we can add weak to the given type.
159 bool canApplyWeak(ASTContext &Ctx, QualType type,
160                   bool AllowOnUnknownClass = false);
161 
162 bool isPlusOneAssign(const BinaryOperator *E);
163 bool isPlusOne(const Expr *E);
164 
165 /// 'Loc' is the end of a statement range. This returns the location
166 /// immediately after the semicolon following the statement.
167 /// If no semicolon is found or the location is inside a macro, the returned
168 /// source location will be invalid.
169 SourceLocation findLocationAfterSemi(SourceLocation loc, ASTContext &Ctx,
170                                      bool IsDecl = false);
171 
172 /// 'Loc' is the end of a statement range. This returns the location
173 /// of the semicolon following the statement.
174 /// If no semicolon is found or the location is inside a macro, the returned
175 /// source location will be invalid.
176 SourceLocation findSemiAfterLocation(SourceLocation loc, ASTContext &Ctx,
177                                      bool IsDecl = false);
178 
179 bool hasSideEffects(Expr *E, ASTContext &Ctx);
180 bool isGlobalVar(Expr *E);
181 /// Returns "nil" or "0" if 'nil' macro is not actually defined.
182 StringRef getNilString(MigrationPass &Pass);
183 
184 template <typename BODY_TRANS>
185 class BodyTransform : public RecursiveASTVisitor<BodyTransform<BODY_TRANS> > {
186   MigrationPass &Pass;
187   Decl *ParentD;
188 
189   typedef RecursiveASTVisitor<BodyTransform<BODY_TRANS> > base;
190 public:
191   BodyTransform(MigrationPass &pass) : Pass(pass), ParentD(nullptr) { }
192 
193   bool TraverseStmt(Stmt *rootS) {
194     if (rootS)
195       BODY_TRANS(Pass).transformBody(rootS, ParentD);
196     return true;
197   }
198 
199   bool TraverseObjCMethodDecl(ObjCMethodDecl *D) {
200     SaveAndRestore<Decl *> SetParent(ParentD, D);
201     return base::TraverseObjCMethodDecl(D);
202   }
203 };
204 
205 typedef llvm::DenseSet<Expr *> ExprSet;
206 
207 void clearRefsIn(Stmt *S, ExprSet &refs);
208 template <typename iterator>
209 void clearRefsIn(iterator begin, iterator end, ExprSet &refs) {
210   for (; begin != end; ++begin)
211     clearRefsIn(*begin, refs);
212 }
213 
214 void collectRefs(ValueDecl *D, Stmt *S, ExprSet &refs);
215 
216 void collectRemovables(Stmt *S, ExprSet &exprs);
217 
218 } // end namespace trans
219 
220 } // end namespace arcmt
221 
222 } // end namespace clang
223 
224 #endif
225