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
20using namespace clang;
21using namespace arcmt;
22using namespace trans;
23
24namespace {
25
26/// \brief Collects all the places where GC attributes __strong/__weak occur.
27class GCAttrsCollector : public RecursiveASTVisitor<GCAttrsCollector> {
28  MigrationContext &MigrateCtx;
29  bool FullyMigratable;
30  std::vector<ObjCPropertyDecl *> &AllProps;
31
32  typedef RecursiveASTVisitor<GCAttrsCollector> base;
33public:
34  GCAttrsCollector(MigrationContext &ctx,
35                   std::vector<ObjCPropertyDecl *> &AllProps)
36    : MigrateCtx(ctx), FullyMigratable(false),
37      AllProps(AllProps) { }
38
39  bool shouldWalkTypesOfTypeLocs() const { return false; }
40
41  bool VisitAttributedTypeLoc(AttributedTypeLoc TL) {
42    handleAttr(TL);
43    return true;
44  }
45
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
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
83  bool handleAttr(AttributedTypeLoc TL, Decl *D = 0) {
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
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 (CXXRecordDecl::method_iterator
138             MI = RD->method_begin(), ME = RD->method_end(); MI != ME; ++MI) {
139        if (MI->isOutOfLine())
140          return true;
141      }
142      return false;
143    }
144
145    return isMigratable(cast<Decl>(D->getDeclContext()));
146  }
147
148  static bool hasObjCImpl(Decl *D) {
149    if (!D)
150      return false;
151    if (ObjCContainerDecl *ContD = dyn_cast<ObjCContainerDecl>(D)) {
152      if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(ContD))
153        return ID->getImplementation() != 0;
154      if (ObjCCategoryDecl *CD = dyn_cast<ObjCCategoryDecl>(ContD))
155        return CD->getImplementation() != 0;
156      if (isa<ObjCImplDecl>(ContD))
157        return true;
158      return false;
159    }
160    return false;
161  }
162
163  bool isInMainFile(Decl *D) {
164    if (!D)
165      return false;
166
167    for (Decl::redecl_iterator
168           I = D->redecls_begin(), E = D->redecls_end(); I != E; ++I)
169      if (!isInMainFile(I->getLocation()))
170        return false;
171
172    return true;
173  }
174
175  bool isInMainFile(SourceLocation Loc) {
176    if (Loc.isInvalid())
177      return false;
178
179    SourceManager &SM = MigrateCtx.Pass.Ctx.getSourceManager();
180    return SM.isInFileID(SM.getExpansionLoc(Loc), SM.getMainFileID());
181  }
182};
183
184} // anonymous namespace
185
186static void errorForGCAttrsOnNonObjC(MigrationContext &MigrateCtx) {
187  TransformActions &TA = MigrateCtx.Pass.TA;
188
189  for (unsigned i = 0, e = MigrateCtx.GCAttrs.size(); i != e; ++i) {
190    MigrationContext::GCAttrOccurrence &Attr = MigrateCtx.GCAttrs[i];
191    if (Attr.FullyMigratable && Attr.Dcl) {
192      if (Attr.ModifiedType.isNull())
193        continue;
194      if (!Attr.ModifiedType->isObjCRetainableType()) {
195        TA.reportError("GC managed memory will become unmanaged in ARC",
196                       Attr.Loc);
197      }
198    }
199  }
200}
201
202static void checkWeakGCAttrs(MigrationContext &MigrateCtx) {
203  TransformActions &TA = MigrateCtx.Pass.TA;
204
205  for (unsigned i = 0, e = MigrateCtx.GCAttrs.size(); i != e; ++i) {
206    MigrationContext::GCAttrOccurrence &Attr = MigrateCtx.GCAttrs[i];
207    if (Attr.Kind == MigrationContext::GCAttrOccurrence::Weak) {
208      if (Attr.ModifiedType.isNull() ||
209          !Attr.ModifiedType->isObjCRetainableType())
210        continue;
211      if (!canApplyWeak(MigrateCtx.Pass.Ctx, Attr.ModifiedType,
212                        /*AllowOnUnknownClass=*/true)) {
213        Transaction Trans(TA);
214        if (!MigrateCtx.RemovedAttrSet.count(Attr.Loc.getRawEncoding()))
215          TA.replaceText(Attr.Loc, "__weak", "__unsafe_unretained");
216        TA.clearDiagnostic(diag::err_arc_weak_no_runtime,
217                           diag::err_arc_unsupported_weak_class,
218                           Attr.Loc);
219      }
220    }
221  }
222}
223
224typedef llvm::TinyPtrVector<ObjCPropertyDecl *> IndivPropsTy;
225
226static void checkAllAtProps(MigrationContext &MigrateCtx,
227                            SourceLocation AtLoc,
228                            IndivPropsTy &IndProps) {
229  if (IndProps.empty())
230    return;
231
232  for (IndivPropsTy::iterator
233         PI = IndProps.begin(), PE = IndProps.end(); PI != PE; ++PI) {
234    QualType T = (*PI)->getType();
235    if (T.isNull() || !T->isObjCRetainableType())
236      return;
237  }
238
239  SmallVector<std::pair<AttributedTypeLoc, ObjCPropertyDecl *>, 4> ATLs;
240  bool hasWeak = false, hasStrong = false;
241  ObjCPropertyDecl::PropertyAttributeKind
242    Attrs = ObjCPropertyDecl::OBJC_PR_noattr;
243  for (IndivPropsTy::iterator
244         PI = IndProps.begin(), PE = IndProps.end(); PI != PE; ++PI) {
245    ObjCPropertyDecl *PD = *PI;
246    Attrs = PD->getPropertyAttributesAsWritten();
247    TypeSourceInfo *TInfo = PD->getTypeSourceInfo();
248    if (!TInfo)
249      return;
250    TypeLoc TL = TInfo->getTypeLoc();
251    if (AttributedTypeLoc ATL =
252            TL.getAs<AttributedTypeLoc>()) {
253      ATLs.push_back(std::make_pair(ATL, PD));
254      if (TInfo->getType().getObjCLifetime() == Qualifiers::OCL_Weak) {
255        hasWeak = true;
256      } else if (TInfo->getType().getObjCLifetime() == Qualifiers::OCL_Strong)
257        hasStrong = true;
258      else
259        return;
260    }
261  }
262  if (ATLs.empty())
263    return;
264  if (hasWeak && hasStrong)
265    return;
266
267  TransformActions &TA = MigrateCtx.Pass.TA;
268  Transaction Trans(TA);
269
270  if (GCAttrsCollector::hasObjCImpl(
271                              cast<Decl>(IndProps.front()->getDeclContext()))) {
272    if (hasWeak)
273      MigrateCtx.AtPropsWeak.insert(AtLoc.getRawEncoding());
274
275  } else {
276    StringRef toAttr = "strong";
277    if (hasWeak) {
278      if (canApplyWeak(MigrateCtx.Pass.Ctx, IndProps.front()->getType(),
279                       /*AllowOnUnkwownClass=*/true))
280        toAttr = "weak";
281      else
282        toAttr = "unsafe_unretained";
283    }
284    if (Attrs & ObjCPropertyDecl::OBJC_PR_assign)
285      MigrateCtx.rewritePropertyAttribute("assign", toAttr, AtLoc);
286    else
287      MigrateCtx.addPropertyAttribute(toAttr, AtLoc);
288  }
289
290  for (unsigned i = 0, e = ATLs.size(); i != e; ++i) {
291    SourceLocation Loc = ATLs[i].first.getAttrNameLoc();
292    if (Loc.isMacroID())
293      Loc = MigrateCtx.Pass.Ctx.getSourceManager()
294                                         .getImmediateExpansionRange(Loc).first;
295    TA.remove(Loc);
296    TA.clearDiagnostic(diag::err_objc_property_attr_mutually_exclusive, AtLoc);
297    TA.clearDiagnostic(diag::err_arc_inconsistent_property_ownership,
298                       ATLs[i].second->getLocation());
299    MigrateCtx.RemovedAttrSet.insert(Loc.getRawEncoding());
300  }
301}
302
303static void checkAllProps(MigrationContext &MigrateCtx,
304                          std::vector<ObjCPropertyDecl *> &AllProps) {
305  typedef llvm::TinyPtrVector<ObjCPropertyDecl *> IndivPropsTy;
306  llvm::DenseMap<unsigned, IndivPropsTy> AtProps;
307
308  for (unsigned i = 0, e = AllProps.size(); i != e; ++i) {
309    ObjCPropertyDecl *PD = AllProps[i];
310    if (PD->getPropertyAttributesAsWritten() &
311          (ObjCPropertyDecl::OBJC_PR_assign |
312           ObjCPropertyDecl::OBJC_PR_readonly)) {
313      SourceLocation AtLoc = PD->getAtLoc();
314      if (AtLoc.isInvalid())
315        continue;
316      unsigned RawAt = AtLoc.getRawEncoding();
317      AtProps[RawAt].push_back(PD);
318    }
319  }
320
321  for (llvm::DenseMap<unsigned, IndivPropsTy>::iterator
322         I = AtProps.begin(), E = AtProps.end(); I != E; ++I) {
323    SourceLocation AtLoc = SourceLocation::getFromRawEncoding(I->first);
324    IndivPropsTy &IndProps = I->second;
325    checkAllAtProps(MigrateCtx, AtLoc, IndProps);
326  }
327}
328
329void GCAttrsTraverser::traverseTU(MigrationContext &MigrateCtx) {
330  std::vector<ObjCPropertyDecl *> AllProps;
331  GCAttrsCollector(MigrateCtx, AllProps).TraverseDecl(
332                                  MigrateCtx.Pass.Ctx.getTranslationUnitDecl());
333
334  errorForGCAttrsOnNonObjC(MigrateCtx);
335  checkAllProps(MigrateCtx, AllProps);
336  checkWeakGCAttrs(MigrateCtx);
337}
338
339void MigrationContext::dumpGCAttrs() {
340  llvm::errs() << "\n################\n";
341  for (unsigned i = 0, e = GCAttrs.size(); i != e; ++i) {
342    GCAttrOccurrence &Attr = GCAttrs[i];
343    llvm::errs() << "KIND: "
344        << (Attr.Kind == GCAttrOccurrence::Strong ? "strong" : "weak");
345    llvm::errs() << "\nLOC: ";
346    Attr.Loc.dump(Pass.Ctx.getSourceManager());
347    llvm::errs() << "\nTYPE: ";
348    Attr.ModifiedType.dump();
349    if (Attr.Dcl) {
350      llvm::errs() << "DECL:\n";
351      Attr.Dcl->dump();
352    } else {
353      llvm::errs() << "DECL: NONE";
354    }
355    llvm::errs() << "\nMIGRATABLE: " << Attr.FullyMigratable;
356    llvm::errs() << "\n----------------\n";
357  }
358  llvm::errs() << "\n################\n";
359}
360