1 //===--- Transforms.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/AST/RecursiveASTVisitor.h"
14 #include "clang/AST/StmtVisitor.h"
15 #include "clang/Analysis/DomainSpecific/CocoaConventions.h"
16 #include "clang/Basic/SourceManager.h"
17 #include "clang/Basic/TargetInfo.h"
18 #include "clang/Lex/Lexer.h"
19 #include "clang/Lex/Preprocessor.h"
20 #include "clang/Sema/Sema.h"
21 #include "clang/Sema/SemaDiagnostic.h"
22 #include "llvm/ADT/DenseSet.h"
23 #include "llvm/ADT/StringSwitch.h"
24 #include <map>
25
26 using namespace clang;
27 using namespace arcmt;
28 using namespace trans;
29
~ASTTraverser()30 ASTTraverser::~ASTTraverser() { }
31
CFBridgingFunctionsDefined()32 bool MigrationPass::CFBridgingFunctionsDefined() {
33 if (!EnableCFBridgeFns.hasValue())
34 EnableCFBridgeFns = SemaRef.isKnownName("CFBridgingRetain") &&
35 SemaRef.isKnownName("CFBridgingRelease");
36 return *EnableCFBridgeFns;
37 }
38
39 //===----------------------------------------------------------------------===//
40 // Helpers.
41 //===----------------------------------------------------------------------===//
42
canApplyWeak(ASTContext & Ctx,QualType type,bool AllowOnUnknownClass)43 bool trans::canApplyWeak(ASTContext &Ctx, QualType type,
44 bool AllowOnUnknownClass) {
45 if (!Ctx.getLangOpts().ObjCWeakRuntime)
46 return false;
47
48 QualType T = type;
49 if (T.isNull())
50 return false;
51
52 // iOS is always safe to use 'weak'.
53 if (Ctx.getTargetInfo().getTriple().isiOS() ||
54 Ctx.getTargetInfo().getTriple().isWatchOS())
55 AllowOnUnknownClass = true;
56
57 while (const PointerType *ptr = T->getAs<PointerType>())
58 T = ptr->getPointeeType();
59 if (const ObjCObjectPointerType *ObjT = T->getAs<ObjCObjectPointerType>()) {
60 ObjCInterfaceDecl *Class = ObjT->getInterfaceDecl();
61 if (!AllowOnUnknownClass && (!Class || Class->getName() == "NSObject"))
62 return false; // id/NSObject is not safe for weak.
63 if (!AllowOnUnknownClass && !Class->hasDefinition())
64 return false; // forward classes are not verifiable, therefore not safe.
65 if (Class && Class->isArcWeakrefUnavailable())
66 return false;
67 }
68
69 return true;
70 }
71
isPlusOneAssign(const BinaryOperator * E)72 bool trans::isPlusOneAssign(const BinaryOperator *E) {
73 if (E->getOpcode() != BO_Assign)
74 return false;
75
76 return isPlusOne(E->getRHS());
77 }
78
isPlusOne(const Expr * E)79 bool trans::isPlusOne(const Expr *E) {
80 if (!E)
81 return false;
82 if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(E))
83 E = EWC->getSubExpr();
84
85 if (const ObjCMessageExpr *
86 ME = dyn_cast<ObjCMessageExpr>(E->IgnoreParenCasts()))
87 if (ME->getMethodFamily() == OMF_retain)
88 return true;
89
90 if (const CallExpr *
91 callE = dyn_cast<CallExpr>(E->IgnoreParenCasts())) {
92 if (const FunctionDecl *FD = callE->getDirectCallee()) {
93 if (FD->hasAttr<CFReturnsRetainedAttr>())
94 return true;
95
96 if (FD->isGlobal() &&
97 FD->getIdentifier() &&
98 FD->getParent()->isTranslationUnit() &&
99 FD->isExternallyVisible() &&
100 ento::cocoa::isRefType(callE->getType(), "CF",
101 FD->getIdentifier()->getName())) {
102 StringRef fname = FD->getIdentifier()->getName();
103 if (fname.endswith("Retain") ||
104 fname.find("Create") != StringRef::npos ||
105 fname.find("Copy") != StringRef::npos) {
106 return true;
107 }
108 }
109 }
110 }
111
112 const ImplicitCastExpr *implCE = dyn_cast<ImplicitCastExpr>(E);
113 while (implCE && implCE->getCastKind() == CK_BitCast)
114 implCE = dyn_cast<ImplicitCastExpr>(implCE->getSubExpr());
115
116 return implCE && implCE->getCastKind() == CK_ARCConsumeObject;
117 }
118
119 /// \brief 'Loc' is the end of a statement range. This returns the location
120 /// immediately after the semicolon following the statement.
121 /// If no semicolon is found or the location is inside a macro, the returned
122 /// source location will be invalid.
findLocationAfterSemi(SourceLocation loc,ASTContext & Ctx,bool IsDecl)123 SourceLocation trans::findLocationAfterSemi(SourceLocation loc,
124 ASTContext &Ctx, bool IsDecl) {
125 SourceLocation SemiLoc = findSemiAfterLocation(loc, Ctx, IsDecl);
126 if (SemiLoc.isInvalid())
127 return SourceLocation();
128 return SemiLoc.getLocWithOffset(1);
129 }
130
131 /// \brief \arg Loc is the end of a statement range. This returns the location
132 /// of the semicolon following the statement.
133 /// If no semicolon is found or the location is inside a macro, the returned
134 /// source location will be invalid.
findSemiAfterLocation(SourceLocation loc,ASTContext & Ctx,bool IsDecl)135 SourceLocation trans::findSemiAfterLocation(SourceLocation loc,
136 ASTContext &Ctx,
137 bool IsDecl) {
138 SourceManager &SM = Ctx.getSourceManager();
139 if (loc.isMacroID()) {
140 if (!Lexer::isAtEndOfMacroExpansion(loc, SM, Ctx.getLangOpts(), &loc))
141 return SourceLocation();
142 }
143 loc = Lexer::getLocForEndOfToken(loc, /*Offset=*/0, SM, Ctx.getLangOpts());
144
145 // Break down the source location.
146 std::pair<FileID, unsigned> locInfo = SM.getDecomposedLoc(loc);
147
148 // Try to load the file buffer.
149 bool invalidTemp = false;
150 StringRef file = SM.getBufferData(locInfo.first, &invalidTemp);
151 if (invalidTemp)
152 return SourceLocation();
153
154 const char *tokenBegin = file.data() + locInfo.second;
155
156 // Lex from the start of the given location.
157 Lexer lexer(SM.getLocForStartOfFile(locInfo.first),
158 Ctx.getLangOpts(),
159 file.begin(), tokenBegin, file.end());
160 Token tok;
161 lexer.LexFromRawLexer(tok);
162 if (tok.isNot(tok::semi)) {
163 if (!IsDecl)
164 return SourceLocation();
165 // Declaration may be followed with other tokens; such as an __attribute,
166 // before ending with a semicolon.
167 return findSemiAfterLocation(tok.getLocation(), Ctx, /*IsDecl*/true);
168 }
169
170 return tok.getLocation();
171 }
172
hasSideEffects(Expr * E,ASTContext & Ctx)173 bool trans::hasSideEffects(Expr *E, ASTContext &Ctx) {
174 if (!E || !E->HasSideEffects(Ctx))
175 return false;
176
177 E = E->IgnoreParenCasts();
178 ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E);
179 if (!ME)
180 return true;
181 switch (ME->getMethodFamily()) {
182 case OMF_autorelease:
183 case OMF_dealloc:
184 case OMF_release:
185 case OMF_retain:
186 switch (ME->getReceiverKind()) {
187 case ObjCMessageExpr::SuperInstance:
188 return false;
189 case ObjCMessageExpr::Instance:
190 return hasSideEffects(ME->getInstanceReceiver(), Ctx);
191 default:
192 break;
193 }
194 break;
195 default:
196 break;
197 }
198
199 return true;
200 }
201
isGlobalVar(Expr * E)202 bool trans::isGlobalVar(Expr *E) {
203 E = E->IgnoreParenCasts();
204 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
205 return DRE->getDecl()->getDeclContext()->isFileContext() &&
206 DRE->getDecl()->isExternallyVisible();
207 if (ConditionalOperator *condOp = dyn_cast<ConditionalOperator>(E))
208 return isGlobalVar(condOp->getTrueExpr()) &&
209 isGlobalVar(condOp->getFalseExpr());
210
211 return false;
212 }
213
getNilString(MigrationPass & Pass)214 StringRef trans::getNilString(MigrationPass &Pass) {
215 return Pass.SemaRef.PP.isMacroDefined("nil") ? "nil" : "0";
216 }
217
218 namespace {
219
220 class ReferenceClear : public RecursiveASTVisitor<ReferenceClear> {
221 ExprSet &Refs;
222 public:
ReferenceClear(ExprSet & refs)223 ReferenceClear(ExprSet &refs) : Refs(refs) { }
VisitDeclRefExpr(DeclRefExpr * E)224 bool VisitDeclRefExpr(DeclRefExpr *E) { Refs.erase(E); return true; }
225 };
226
227 class ReferenceCollector : public RecursiveASTVisitor<ReferenceCollector> {
228 ValueDecl *Dcl;
229 ExprSet &Refs;
230
231 public:
ReferenceCollector(ValueDecl * D,ExprSet & refs)232 ReferenceCollector(ValueDecl *D, ExprSet &refs)
233 : Dcl(D), Refs(refs) { }
234
VisitDeclRefExpr(DeclRefExpr * E)235 bool VisitDeclRefExpr(DeclRefExpr *E) {
236 if (E->getDecl() == Dcl)
237 Refs.insert(E);
238 return true;
239 }
240 };
241
242 class RemovablesCollector : public RecursiveASTVisitor<RemovablesCollector> {
243 ExprSet &Removables;
244
245 public:
RemovablesCollector(ExprSet & removables)246 RemovablesCollector(ExprSet &removables)
247 : Removables(removables) { }
248
shouldWalkTypesOfTypeLocs() const249 bool shouldWalkTypesOfTypeLocs() const { return false; }
250
TraverseStmtExpr(StmtExpr * E)251 bool TraverseStmtExpr(StmtExpr *E) {
252 CompoundStmt *S = E->getSubStmt();
253 for (CompoundStmt::body_iterator
254 I = S->body_begin(), E = S->body_end(); I != E; ++I) {
255 if (I != E - 1)
256 mark(*I);
257 TraverseStmt(*I);
258 }
259 return true;
260 }
261
VisitCompoundStmt(CompoundStmt * S)262 bool VisitCompoundStmt(CompoundStmt *S) {
263 for (auto *I : S->body())
264 mark(I);
265 return true;
266 }
267
VisitIfStmt(IfStmt * S)268 bool VisitIfStmt(IfStmt *S) {
269 mark(S->getThen());
270 mark(S->getElse());
271 return true;
272 }
273
VisitWhileStmt(WhileStmt * S)274 bool VisitWhileStmt(WhileStmt *S) {
275 mark(S->getBody());
276 return true;
277 }
278
VisitDoStmt(DoStmt * S)279 bool VisitDoStmt(DoStmt *S) {
280 mark(S->getBody());
281 return true;
282 }
283
VisitForStmt(ForStmt * S)284 bool VisitForStmt(ForStmt *S) {
285 mark(S->getInit());
286 mark(S->getInc());
287 mark(S->getBody());
288 return true;
289 }
290
291 private:
mark(Stmt * S)292 void mark(Stmt *S) {
293 if (!S) return;
294
295 while (LabelStmt *Label = dyn_cast<LabelStmt>(S))
296 S = Label->getSubStmt();
297 S = S->IgnoreImplicit();
298 if (Expr *E = dyn_cast<Expr>(S))
299 Removables.insert(E);
300 }
301 };
302
303 } // end anonymous namespace
304
clearRefsIn(Stmt * S,ExprSet & refs)305 void trans::clearRefsIn(Stmt *S, ExprSet &refs) {
306 ReferenceClear(refs).TraverseStmt(S);
307 }
308
collectRefs(ValueDecl * D,Stmt * S,ExprSet & refs)309 void trans::collectRefs(ValueDecl *D, Stmt *S, ExprSet &refs) {
310 ReferenceCollector(D, refs).TraverseStmt(S);
311 }
312
collectRemovables(Stmt * S,ExprSet & exprs)313 void trans::collectRemovables(Stmt *S, ExprSet &exprs) {
314 RemovablesCollector(exprs).TraverseStmt(S);
315 }
316
317 //===----------------------------------------------------------------------===//
318 // MigrationContext
319 //===----------------------------------------------------------------------===//
320
321 namespace {
322
323 class ASTTransform : public RecursiveASTVisitor<ASTTransform> {
324 MigrationContext &MigrateCtx;
325 typedef RecursiveASTVisitor<ASTTransform> base;
326
327 public:
ASTTransform(MigrationContext & MigrateCtx)328 ASTTransform(MigrationContext &MigrateCtx) : MigrateCtx(MigrateCtx) { }
329
shouldWalkTypesOfTypeLocs() const330 bool shouldWalkTypesOfTypeLocs() const { return false; }
331
TraverseObjCImplementationDecl(ObjCImplementationDecl * D)332 bool TraverseObjCImplementationDecl(ObjCImplementationDecl *D) {
333 ObjCImplementationContext ImplCtx(MigrateCtx, D);
334 for (MigrationContext::traverser_iterator
335 I = MigrateCtx.traversers_begin(),
336 E = MigrateCtx.traversers_end(); I != E; ++I)
337 (*I)->traverseObjCImplementation(ImplCtx);
338
339 return base::TraverseObjCImplementationDecl(D);
340 }
341
TraverseStmt(Stmt * rootS)342 bool TraverseStmt(Stmt *rootS) {
343 if (!rootS)
344 return true;
345
346 BodyContext BodyCtx(MigrateCtx, rootS);
347 for (MigrationContext::traverser_iterator
348 I = MigrateCtx.traversers_begin(),
349 E = MigrateCtx.traversers_end(); I != E; ++I)
350 (*I)->traverseBody(BodyCtx);
351
352 return true;
353 }
354 };
355
356 }
357
~MigrationContext()358 MigrationContext::~MigrationContext() {
359 for (traverser_iterator
360 I = traversers_begin(), E = traversers_end(); I != E; ++I)
361 delete *I;
362 }
363
isGCOwnedNonObjC(QualType T)364 bool MigrationContext::isGCOwnedNonObjC(QualType T) {
365 while (!T.isNull()) {
366 if (const AttributedType *AttrT = T->getAs<AttributedType>()) {
367 if (AttrT->getAttrKind() == AttributedType::attr_objc_ownership)
368 return !AttrT->getModifiedType()->isObjCRetainableType();
369 }
370
371 if (T->isArrayType())
372 T = Pass.Ctx.getBaseElementType(T);
373 else if (const PointerType *PT = T->getAs<PointerType>())
374 T = PT->getPointeeType();
375 else if (const ReferenceType *RT = T->getAs<ReferenceType>())
376 T = RT->getPointeeType();
377 else
378 break;
379 }
380
381 return false;
382 }
383
rewritePropertyAttribute(StringRef fromAttr,StringRef toAttr,SourceLocation atLoc)384 bool MigrationContext::rewritePropertyAttribute(StringRef fromAttr,
385 StringRef toAttr,
386 SourceLocation atLoc) {
387 if (atLoc.isMacroID())
388 return false;
389
390 SourceManager &SM = Pass.Ctx.getSourceManager();
391
392 // Break down the source location.
393 std::pair<FileID, unsigned> locInfo = SM.getDecomposedLoc(atLoc);
394
395 // Try to load the file buffer.
396 bool invalidTemp = false;
397 StringRef file = SM.getBufferData(locInfo.first, &invalidTemp);
398 if (invalidTemp)
399 return false;
400
401 const char *tokenBegin = file.data() + locInfo.second;
402
403 // Lex from the start of the given location.
404 Lexer lexer(SM.getLocForStartOfFile(locInfo.first),
405 Pass.Ctx.getLangOpts(),
406 file.begin(), tokenBegin, file.end());
407 Token tok;
408 lexer.LexFromRawLexer(tok);
409 if (tok.isNot(tok::at)) return false;
410 lexer.LexFromRawLexer(tok);
411 if (tok.isNot(tok::raw_identifier)) return false;
412 if (tok.getRawIdentifier() != "property")
413 return false;
414 lexer.LexFromRawLexer(tok);
415 if (tok.isNot(tok::l_paren)) return false;
416
417 Token BeforeTok = tok;
418 Token AfterTok;
419 AfterTok.startToken();
420 SourceLocation AttrLoc;
421
422 lexer.LexFromRawLexer(tok);
423 if (tok.is(tok::r_paren))
424 return false;
425
426 while (1) {
427 if (tok.isNot(tok::raw_identifier)) return false;
428 if (tok.getRawIdentifier() == fromAttr) {
429 if (!toAttr.empty()) {
430 Pass.TA.replaceText(tok.getLocation(), fromAttr, toAttr);
431 return true;
432 }
433 // We want to remove the attribute.
434 AttrLoc = tok.getLocation();
435 }
436
437 do {
438 lexer.LexFromRawLexer(tok);
439 if (AttrLoc.isValid() && AfterTok.is(tok::unknown))
440 AfterTok = tok;
441 } while (tok.isNot(tok::comma) && tok.isNot(tok::r_paren));
442 if (tok.is(tok::r_paren))
443 break;
444 if (AttrLoc.isInvalid())
445 BeforeTok = tok;
446 lexer.LexFromRawLexer(tok);
447 }
448
449 if (toAttr.empty() && AttrLoc.isValid() && AfterTok.isNot(tok::unknown)) {
450 // We want to remove the attribute.
451 if (BeforeTok.is(tok::l_paren) && AfterTok.is(tok::r_paren)) {
452 Pass.TA.remove(SourceRange(BeforeTok.getLocation(),
453 AfterTok.getLocation()));
454 } else if (BeforeTok.is(tok::l_paren) && AfterTok.is(tok::comma)) {
455 Pass.TA.remove(SourceRange(AttrLoc, AfterTok.getLocation()));
456 } else {
457 Pass.TA.remove(SourceRange(BeforeTok.getLocation(), AttrLoc));
458 }
459
460 return true;
461 }
462
463 return false;
464 }
465
addPropertyAttribute(StringRef attr,SourceLocation atLoc)466 bool MigrationContext::addPropertyAttribute(StringRef attr,
467 SourceLocation atLoc) {
468 if (atLoc.isMacroID())
469 return false;
470
471 SourceManager &SM = Pass.Ctx.getSourceManager();
472
473 // Break down the source location.
474 std::pair<FileID, unsigned> locInfo = SM.getDecomposedLoc(atLoc);
475
476 // Try to load the file buffer.
477 bool invalidTemp = false;
478 StringRef file = SM.getBufferData(locInfo.first, &invalidTemp);
479 if (invalidTemp)
480 return false;
481
482 const char *tokenBegin = file.data() + locInfo.second;
483
484 // Lex from the start of the given location.
485 Lexer lexer(SM.getLocForStartOfFile(locInfo.first),
486 Pass.Ctx.getLangOpts(),
487 file.begin(), tokenBegin, file.end());
488 Token tok;
489 lexer.LexFromRawLexer(tok);
490 if (tok.isNot(tok::at)) return false;
491 lexer.LexFromRawLexer(tok);
492 if (tok.isNot(tok::raw_identifier)) return false;
493 if (tok.getRawIdentifier() != "property")
494 return false;
495 lexer.LexFromRawLexer(tok);
496
497 if (tok.isNot(tok::l_paren)) {
498 Pass.TA.insert(tok.getLocation(), std::string("(") + attr.str() + ") ");
499 return true;
500 }
501
502 lexer.LexFromRawLexer(tok);
503 if (tok.is(tok::r_paren)) {
504 Pass.TA.insert(tok.getLocation(), attr);
505 return true;
506 }
507
508 if (tok.isNot(tok::raw_identifier)) return false;
509
510 Pass.TA.insert(tok.getLocation(), std::string(attr) + ", ");
511 return true;
512 }
513
traverse(TranslationUnitDecl * TU)514 void MigrationContext::traverse(TranslationUnitDecl *TU) {
515 for (traverser_iterator
516 I = traversers_begin(), E = traversers_end(); I != E; ++I)
517 (*I)->traverseTU(*this);
518
519 ASTTransform(*this).TraverseDecl(TU);
520 }
521
GCRewriteFinalize(MigrationPass & pass)522 static void GCRewriteFinalize(MigrationPass &pass) {
523 ASTContext &Ctx = pass.Ctx;
524 TransformActions &TA = pass.TA;
525 DeclContext *DC = Ctx.getTranslationUnitDecl();
526 Selector FinalizeSel =
527 Ctx.Selectors.getNullarySelector(&pass.Ctx.Idents.get("finalize"));
528
529 typedef DeclContext::specific_decl_iterator<ObjCImplementationDecl>
530 impl_iterator;
531 for (impl_iterator I = impl_iterator(DC->decls_begin()),
532 E = impl_iterator(DC->decls_end()); I != E; ++I) {
533 for (const auto *MD : I->instance_methods()) {
534 if (!MD->hasBody())
535 continue;
536
537 if (MD->isInstanceMethod() && MD->getSelector() == FinalizeSel) {
538 const ObjCMethodDecl *FinalizeM = MD;
539 Transaction Trans(TA);
540 TA.insert(FinalizeM->getSourceRange().getBegin(),
541 "#if !__has_feature(objc_arc)\n");
542 CharSourceRange::getTokenRange(FinalizeM->getSourceRange());
543 const SourceManager &SM = pass.Ctx.getSourceManager();
544 const LangOptions &LangOpts = pass.Ctx.getLangOpts();
545 bool Invalid;
546 std::string str = "\n#endif\n";
547 str += Lexer::getSourceText(
548 CharSourceRange::getTokenRange(FinalizeM->getSourceRange()),
549 SM, LangOpts, &Invalid);
550 TA.insertAfterToken(FinalizeM->getSourceRange().getEnd(), str);
551
552 break;
553 }
554 }
555 }
556 }
557
558 //===----------------------------------------------------------------------===//
559 // getAllTransformations.
560 //===----------------------------------------------------------------------===//
561
traverseAST(MigrationPass & pass)562 static void traverseAST(MigrationPass &pass) {
563 MigrationContext MigrateCtx(pass);
564
565 if (pass.isGCMigration()) {
566 MigrateCtx.addTraverser(new GCCollectableCallsTraverser);
567 MigrateCtx.addTraverser(new GCAttrsTraverser());
568 }
569 MigrateCtx.addTraverser(new PropertyRewriteTraverser());
570 MigrateCtx.addTraverser(new BlockObjCVariableTraverser());
571 MigrateCtx.addTraverser(new ProtectedScopeTraverser());
572
573 MigrateCtx.traverse(pass.Ctx.getTranslationUnitDecl());
574 }
575
independentTransforms(MigrationPass & pass)576 static void independentTransforms(MigrationPass &pass) {
577 rewriteAutoreleasePool(pass);
578 removeRetainReleaseDeallocFinalize(pass);
579 rewriteUnusedInitDelegate(pass);
580 removeZeroOutPropsInDeallocFinalize(pass);
581 makeAssignARCSafe(pass);
582 rewriteUnbridgedCasts(pass);
583 checkAPIUses(pass);
584 traverseAST(pass);
585 }
586
getAllTransformations(LangOptions::GCMode OrigGCMode,bool NoFinalizeRemoval)587 std::vector<TransformFn> arcmt::getAllTransformations(
588 LangOptions::GCMode OrigGCMode,
589 bool NoFinalizeRemoval) {
590 std::vector<TransformFn> transforms;
591
592 if (OrigGCMode == LangOptions::GCOnly && NoFinalizeRemoval)
593 transforms.push_back(GCRewriteFinalize);
594 transforms.push_back(independentTransforms);
595 // This depends on previous transformations removing various expressions.
596 transforms.push_back(removeEmptyStatementsAndDeallocFinalize);
597
598 return transforms;
599 }
600