1 //===--- TransGCAttrs.cpp - Transformations 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 #include "Transforms.h"
11 #include "Internals.h"
12 #include "clang/AST/ASTContext.h"
13 #include "clang/Basic/SourceManager.h"
14 #include "clang/Lex/Lexer.h"
15 #include "clang/Sema/SemaDiagnostic.h"
16 #include "llvm/ADT/SmallString.h"
17 #include "llvm/ADT/TinyPtrVector.h"
18 #include "llvm/Support/SaveAndRestore.h"
19
20 using namespace clang;
21 using namespace arcmt;
22 using namespace trans;
23
24 namespace {
25
26 /// \brief Collects all the places where GC attributes __strong/__weak occur.
27 class GCAttrsCollector : public RecursiveASTVisitor<GCAttrsCollector> {
28 MigrationContext &MigrateCtx;
29 bool FullyMigratable;
30 std::vector<ObjCPropertyDecl *> &AllProps;
31
32 typedef RecursiveASTVisitor<GCAttrsCollector> base;
33 public:
GCAttrsCollector(MigrationContext & ctx,std::vector<ObjCPropertyDecl * > & AllProps)34 GCAttrsCollector(MigrationContext &ctx,
35 std::vector<ObjCPropertyDecl *> &AllProps)
36 : MigrateCtx(ctx), FullyMigratable(false),
37 AllProps(AllProps) { }
38
shouldWalkTypesOfTypeLocs() const39 bool shouldWalkTypesOfTypeLocs() const { return false; }
40
VisitAttributedTypeLoc(AttributedTypeLoc TL)41 bool VisitAttributedTypeLoc(AttributedTypeLoc TL) {
42 handleAttr(TL);
43 return true;
44 }
45
TraverseDecl(Decl * D)46 bool TraverseDecl(Decl *D) {
47 if (!D || D->isImplicit())
48 return true;
49
50 SaveAndRestore<bool> Save(FullyMigratable, isMigratable(D));
51
52 if (ObjCPropertyDecl *PropD = dyn_cast<ObjCPropertyDecl>(D)) {
53 lookForAttribute(PropD, PropD->getTypeSourceInfo());
54 AllProps.push_back(PropD);
55 } else if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(D)) {
56 lookForAttribute(DD, DD->getTypeSourceInfo());
57 }
58 return base::TraverseDecl(D);
59 }
60
lookForAttribute(Decl * D,TypeSourceInfo * TInfo)61 void lookForAttribute(Decl *D, TypeSourceInfo *TInfo) {
62 if (!TInfo)
63 return;
64 TypeLoc TL = TInfo->getTypeLoc();
65 while (TL) {
66 if (QualifiedTypeLoc QL = TL.getAs<QualifiedTypeLoc>()) {
67 TL = QL.getUnqualifiedLoc();
68 } else if (AttributedTypeLoc Attr = TL.getAs<AttributedTypeLoc>()) {
69 if (handleAttr(Attr, D))
70 break;
71 TL = Attr.getModifiedLoc();
72 } else if (ArrayTypeLoc Arr = TL.getAs<ArrayTypeLoc>()) {
73 TL = Arr.getElementLoc();
74 } else if (PointerTypeLoc PT = TL.getAs<PointerTypeLoc>()) {
75 TL = PT.getPointeeLoc();
76 } else if (ReferenceTypeLoc RT = TL.getAs<ReferenceTypeLoc>())
77 TL = RT.getPointeeLoc();
78 else
79 break;
80 }
81 }
82
handleAttr(AttributedTypeLoc TL,Decl * D=nullptr)83 bool handleAttr(AttributedTypeLoc TL, Decl *D = nullptr) {
84 if (TL.getAttrKind() != AttributedType::attr_objc_ownership)
85 return false;
86
87 SourceLocation Loc = TL.getAttrNameLoc();
88 unsigned RawLoc = Loc.getRawEncoding();
89 if (MigrateCtx.AttrSet.count(RawLoc))
90 return true;
91
92 ASTContext &Ctx = MigrateCtx.Pass.Ctx;
93 SourceManager &SM = Ctx.getSourceManager();
94 if (Loc.isMacroID())
95 Loc = SM.getImmediateExpansionRange(Loc).first;
96 SmallString<32> Buf;
97 bool Invalid = false;
98 StringRef Spell = Lexer::getSpelling(
99 SM.getSpellingLoc(TL.getAttrEnumOperandLoc()),
100 Buf, SM, Ctx.getLangOpts(), &Invalid);
101 if (Invalid)
102 return false;
103 MigrationContext::GCAttrOccurrence::AttrKind Kind;
104 if (Spell == "strong")
105 Kind = MigrationContext::GCAttrOccurrence::Strong;
106 else if (Spell == "weak")
107 Kind = MigrationContext::GCAttrOccurrence::Weak;
108 else
109 return false;
110
111 MigrateCtx.AttrSet.insert(RawLoc);
112 MigrateCtx.GCAttrs.push_back(MigrationContext::GCAttrOccurrence());
113 MigrationContext::GCAttrOccurrence &Attr = MigrateCtx.GCAttrs.back();
114
115 Attr.Kind = Kind;
116 Attr.Loc = Loc;
117 Attr.ModifiedType = TL.getModifiedLoc().getType();
118 Attr.Dcl = D;
119 Attr.FullyMigratable = FullyMigratable;
120 return true;
121 }
122
isMigratable(Decl * D)123 bool isMigratable(Decl *D) {
124 if (isa<TranslationUnitDecl>(D))
125 return false;
126
127 if (isInMainFile(D))
128 return true;
129
130 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
131 return FD->hasBody();
132
133 if (ObjCContainerDecl *ContD = dyn_cast<ObjCContainerDecl>(D))
134 return hasObjCImpl(ContD);
135
136 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D)) {
137 for (const auto *MI : RD->methods()) {
138 if (MI->isOutOfLine())
139 return true;
140 }
141 return false;
142 }
143
144 return isMigratable(cast<Decl>(D->getDeclContext()));
145 }
146
hasObjCImpl(Decl * D)147 static bool hasObjCImpl(Decl *D) {
148 if (!D)
149 return false;
150 if (ObjCContainerDecl *ContD = dyn_cast<ObjCContainerDecl>(D)) {
151 if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(ContD))
152 return ID->getImplementation() != nullptr;
153 if (ObjCCategoryDecl *CD = dyn_cast<ObjCCategoryDecl>(ContD))
154 return CD->getImplementation() != nullptr;
155 return isa<ObjCImplDecl>(ContD);
156 }
157 return false;
158 }
159
isInMainFile(Decl * D)160 bool isInMainFile(Decl *D) {
161 if (!D)
162 return false;
163
164 for (auto I : D->redecls())
165 if (!isInMainFile(I->getLocation()))
166 return false;
167
168 return true;
169 }
170
isInMainFile(SourceLocation Loc)171 bool isInMainFile(SourceLocation Loc) {
172 if (Loc.isInvalid())
173 return false;
174
175 SourceManager &SM = MigrateCtx.Pass.Ctx.getSourceManager();
176 return SM.isInFileID(SM.getExpansionLoc(Loc), SM.getMainFileID());
177 }
178 };
179
180 } // anonymous namespace
181
errorForGCAttrsOnNonObjC(MigrationContext & MigrateCtx)182 static void errorForGCAttrsOnNonObjC(MigrationContext &MigrateCtx) {
183 TransformActions &TA = MigrateCtx.Pass.TA;
184
185 for (unsigned i = 0, e = MigrateCtx.GCAttrs.size(); i != e; ++i) {
186 MigrationContext::GCAttrOccurrence &Attr = MigrateCtx.GCAttrs[i];
187 if (Attr.FullyMigratable && Attr.Dcl) {
188 if (Attr.ModifiedType.isNull())
189 continue;
190 if (!Attr.ModifiedType->isObjCRetainableType()) {
191 TA.reportError("GC managed memory will become unmanaged in ARC",
192 Attr.Loc);
193 }
194 }
195 }
196 }
197
checkWeakGCAttrs(MigrationContext & MigrateCtx)198 static void checkWeakGCAttrs(MigrationContext &MigrateCtx) {
199 TransformActions &TA = MigrateCtx.Pass.TA;
200
201 for (unsigned i = 0, e = MigrateCtx.GCAttrs.size(); i != e; ++i) {
202 MigrationContext::GCAttrOccurrence &Attr = MigrateCtx.GCAttrs[i];
203 if (Attr.Kind == MigrationContext::GCAttrOccurrence::Weak) {
204 if (Attr.ModifiedType.isNull() ||
205 !Attr.ModifiedType->isObjCRetainableType())
206 continue;
207 if (!canApplyWeak(MigrateCtx.Pass.Ctx, Attr.ModifiedType,
208 /*AllowOnUnknownClass=*/true)) {
209 Transaction Trans(TA);
210 if (!MigrateCtx.RemovedAttrSet.count(Attr.Loc.getRawEncoding()))
211 TA.replaceText(Attr.Loc, "__weak", "__unsafe_unretained");
212 TA.clearDiagnostic(diag::err_arc_weak_no_runtime,
213 diag::err_arc_unsupported_weak_class,
214 Attr.Loc);
215 }
216 }
217 }
218 }
219
220 typedef llvm::TinyPtrVector<ObjCPropertyDecl *> IndivPropsTy;
221
checkAllAtProps(MigrationContext & MigrateCtx,SourceLocation AtLoc,IndivPropsTy & IndProps)222 static void checkAllAtProps(MigrationContext &MigrateCtx,
223 SourceLocation AtLoc,
224 IndivPropsTy &IndProps) {
225 if (IndProps.empty())
226 return;
227
228 for (IndivPropsTy::iterator
229 PI = IndProps.begin(), PE = IndProps.end(); PI != PE; ++PI) {
230 QualType T = (*PI)->getType();
231 if (T.isNull() || !T->isObjCRetainableType())
232 return;
233 }
234
235 SmallVector<std::pair<AttributedTypeLoc, ObjCPropertyDecl *>, 4> ATLs;
236 bool hasWeak = false, hasStrong = false;
237 ObjCPropertyDecl::PropertyAttributeKind
238 Attrs = ObjCPropertyDecl::OBJC_PR_noattr;
239 for (IndivPropsTy::iterator
240 PI = IndProps.begin(), PE = IndProps.end(); PI != PE; ++PI) {
241 ObjCPropertyDecl *PD = *PI;
242 Attrs = PD->getPropertyAttributesAsWritten();
243 TypeSourceInfo *TInfo = PD->getTypeSourceInfo();
244 if (!TInfo)
245 return;
246 TypeLoc TL = TInfo->getTypeLoc();
247 if (AttributedTypeLoc ATL =
248 TL.getAs<AttributedTypeLoc>()) {
249 ATLs.push_back(std::make_pair(ATL, PD));
250 if (TInfo->getType().getObjCLifetime() == Qualifiers::OCL_Weak) {
251 hasWeak = true;
252 } else if (TInfo->getType().getObjCLifetime() == Qualifiers::OCL_Strong)
253 hasStrong = true;
254 else
255 return;
256 }
257 }
258 if (ATLs.empty())
259 return;
260 if (hasWeak && hasStrong)
261 return;
262
263 TransformActions &TA = MigrateCtx.Pass.TA;
264 Transaction Trans(TA);
265
266 if (GCAttrsCollector::hasObjCImpl(
267 cast<Decl>(IndProps.front()->getDeclContext()))) {
268 if (hasWeak)
269 MigrateCtx.AtPropsWeak.insert(AtLoc.getRawEncoding());
270
271 } else {
272 StringRef toAttr = "strong";
273 if (hasWeak) {
274 if (canApplyWeak(MigrateCtx.Pass.Ctx, IndProps.front()->getType(),
275 /*AllowOnUnkwownClass=*/true))
276 toAttr = "weak";
277 else
278 toAttr = "unsafe_unretained";
279 }
280 if (Attrs & ObjCPropertyDecl::OBJC_PR_assign)
281 MigrateCtx.rewritePropertyAttribute("assign", toAttr, AtLoc);
282 else
283 MigrateCtx.addPropertyAttribute(toAttr, AtLoc);
284 }
285
286 for (unsigned i = 0, e = ATLs.size(); i != e; ++i) {
287 SourceLocation Loc = ATLs[i].first.getAttrNameLoc();
288 if (Loc.isMacroID())
289 Loc = MigrateCtx.Pass.Ctx.getSourceManager()
290 .getImmediateExpansionRange(Loc).first;
291 TA.remove(Loc);
292 TA.clearDiagnostic(diag::err_objc_property_attr_mutually_exclusive, AtLoc);
293 TA.clearDiagnostic(diag::err_arc_inconsistent_property_ownership,
294 ATLs[i].second->getLocation());
295 MigrateCtx.RemovedAttrSet.insert(Loc.getRawEncoding());
296 }
297 }
298
checkAllProps(MigrationContext & MigrateCtx,std::vector<ObjCPropertyDecl * > & AllProps)299 static void checkAllProps(MigrationContext &MigrateCtx,
300 std::vector<ObjCPropertyDecl *> &AllProps) {
301 typedef llvm::TinyPtrVector<ObjCPropertyDecl *> IndivPropsTy;
302 llvm::DenseMap<unsigned, IndivPropsTy> AtProps;
303
304 for (unsigned i = 0, e = AllProps.size(); i != e; ++i) {
305 ObjCPropertyDecl *PD = AllProps[i];
306 if (PD->getPropertyAttributesAsWritten() &
307 (ObjCPropertyDecl::OBJC_PR_assign |
308 ObjCPropertyDecl::OBJC_PR_readonly)) {
309 SourceLocation AtLoc = PD->getAtLoc();
310 if (AtLoc.isInvalid())
311 continue;
312 unsigned RawAt = AtLoc.getRawEncoding();
313 AtProps[RawAt].push_back(PD);
314 }
315 }
316
317 for (llvm::DenseMap<unsigned, IndivPropsTy>::iterator
318 I = AtProps.begin(), E = AtProps.end(); I != E; ++I) {
319 SourceLocation AtLoc = SourceLocation::getFromRawEncoding(I->first);
320 IndivPropsTy &IndProps = I->second;
321 checkAllAtProps(MigrateCtx, AtLoc, IndProps);
322 }
323 }
324
traverseTU(MigrationContext & MigrateCtx)325 void GCAttrsTraverser::traverseTU(MigrationContext &MigrateCtx) {
326 std::vector<ObjCPropertyDecl *> AllProps;
327 GCAttrsCollector(MigrateCtx, AllProps).TraverseDecl(
328 MigrateCtx.Pass.Ctx.getTranslationUnitDecl());
329
330 errorForGCAttrsOnNonObjC(MigrateCtx);
331 checkAllProps(MigrateCtx, AllProps);
332 checkWeakGCAttrs(MigrateCtx);
333 }
334
dumpGCAttrs()335 void MigrationContext::dumpGCAttrs() {
336 llvm::errs() << "\n################\n";
337 for (unsigned i = 0, e = GCAttrs.size(); i != e; ++i) {
338 GCAttrOccurrence &Attr = GCAttrs[i];
339 llvm::errs() << "KIND: "
340 << (Attr.Kind == GCAttrOccurrence::Strong ? "strong" : "weak");
341 llvm::errs() << "\nLOC: ";
342 Attr.Loc.dump(Pass.Ctx.getSourceManager());
343 llvm::errs() << "\nTYPE: ";
344 Attr.ModifiedType.dump();
345 if (Attr.Dcl) {
346 llvm::errs() << "DECL:\n";
347 Attr.Dcl->dump();
348 } else {
349 llvm::errs() << "DECL: NONE";
350 }
351 llvm::errs() << "\nMIGRATABLE: " << Attr.FullyMigratable;
352 llvm::errs() << "\n----------------\n";
353 }
354 llvm::errs() << "\n################\n";
355 }
356