1 //===--- TransUnbridgedCasts.cpp - Transformations to ARC mode ------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // rewriteUnbridgedCasts:
12 // A cast of non-objc pointer to an objc one is checked. If the non-objc pointer
13 // is from a file-level variable, __bridge cast is used to convert it.
14 // For the result of a function call that we know is +1/+0,
15 // __bridge/CFBridgingRelease is used.
17 // NSString *str = (NSString *)kUTTypePlainText;
18 // str = b ? kUTTypeRTF : kUTTypePlainText;
19 // NSString *_uuidString = (NSString *)CFUUIDCreateString(kCFAllocatorDefault,
22 // NSString *str = (__bridge NSString *)kUTTypePlainText;
23 // str = (__bridge NSString *)(b ? kUTTypeRTF : kUTTypePlainText);
24 // NSString *_uuidString = (NSString *)
25 // CFBridgingRelease(CFUUIDCreateString(kCFAllocatorDefault, _uuid));
27 // For a C pointer to ObjC, for casting 'self', __bridge is used.
29 // CFStringRef str = (CFStringRef)self;
31 // CFStringRef str = (__bridge CFStringRef)self;
33 // Uses of Block_copy/Block_release macros are rewritten:
41 //===----------------------------------------------------------------------===//
43 #include "Transforms.h"
44 #include "Internals.h"
45 #include "clang/AST/ASTContext.h"
46 #include "clang/AST/Attr.h"
47 #include "clang/AST/ParentMap.h"
48 #include "clang/Analysis/DomainSpecific/CocoaConventions.h"
49 #include "clang/Basic/SourceManager.h"
50 #include "clang/Lex/Lexer.h"
51 #include "clang/Sema/SemaDiagnostic.h"
52 #include "llvm/ADT/SmallString.h"
54 using namespace clang;
55 using namespace arcmt;
56 using namespace trans;
60 class UnbridgedCastRewriter : public RecursiveASTVisitor<UnbridgedCastRewriter>{
62 IdentifierInfo *SelfII;
63 OwningPtr<ParentMap> StmtMap;
66 mutable OwningPtr<ExprSet> Removables;
69 UnbridgedCastRewriter(MigrationPass &pass) : Pass(pass), ParentD(0), Body(0) {
70 SelfII = &Pass.Ctx.Idents.get("self");
73 void transformBody(Stmt *body, Decl *ParentD) {
74 this->ParentD = ParentD;
76 StmtMap.reset(new ParentMap(body));
80 bool VisitCastExpr(CastExpr *E) {
81 if (E->getCastKind() != CK_CPointerToObjCPointerCast &&
82 E->getCastKind() != CK_BitCast &&
83 E->getCastKind() != CK_AnyPointerToBlockPointerCast)
86 QualType castType = E->getType();
87 Expr *castExpr = E->getSubExpr();
88 QualType castExprType = castExpr->getType();
90 if (castType->isObjCRetainableType() == castExprType->isObjCRetainableType())
93 bool exprRetainable = castExprType->isObjCIndirectLifetimeType();
94 bool castRetainable = castType->isObjCIndirectLifetimeType();
95 if (exprRetainable == castRetainable) return true;
97 if (castExpr->isNullPointerConstant(Pass.Ctx,
98 Expr::NPC_ValueDependentIsNull))
101 SourceLocation loc = castExpr->getExprLoc();
102 if (loc.isValid() && Pass.Ctx.getSourceManager().isInSystemHeader(loc))
105 if (castType->isObjCRetainableType())
106 transformNonObjCToObjCCast(E);
108 transformObjCToNonObjCCast(E);
114 void transformNonObjCToObjCCast(CastExpr *E) {
117 // Global vars are assumed that are cast as unretained.
119 if (E->getSubExpr()->getType()->isPointerType()) {
120 castToObjCObject(E, /*retained=*/false);
124 // If the cast is directly over the result of a Core Foundation function
125 // try to figure out whether it should be cast as retained or unretained.
126 Expr *inner = E->IgnoreParenCasts();
127 if (CallExpr *callE = dyn_cast<CallExpr>(inner)) {
128 if (FunctionDecl *FD = callE->getDirectCallee()) {
129 if (FD->getAttr<CFReturnsRetainedAttr>()) {
130 castToObjCObject(E, /*retained=*/true);
133 if (FD->getAttr<CFReturnsNotRetainedAttr>()) {
134 castToObjCObject(E, /*retained=*/false);
137 if (FD->isGlobal() &&
138 FD->getIdentifier() &&
139 ento::cocoa::isRefType(E->getSubExpr()->getType(), "CF",
140 FD->getIdentifier()->getName())) {
141 StringRef fname = FD->getIdentifier()->getName();
142 if (fname.endswith("Retain") ||
143 fname.find("Create") != StringRef::npos ||
144 fname.find("Copy") != StringRef::npos) {
145 // Do not migrate to couple of bridge transfer casts which
146 // cancel each other out. Leave it unchanged so error gets user
147 // attention instead.
148 if (FD->getName() == "CFRetain" &&
149 FD->getNumParams() == 1 &&
150 FD->getParent()->isTranslationUnit() &&
151 FD->hasExternalLinkage()) {
152 Expr *Arg = callE->getArg(0);
153 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) {
154 const Expr *sub = ICE->getSubExpr();
155 QualType T = sub->getType();
156 if (T->isObjCObjectPointerType())
160 castToObjCObject(E, /*retained=*/true);
164 if (fname.find("Get") != StringRef::npos) {
165 castToObjCObject(E, /*retained=*/false);
172 // If returning an ivar or a member of an ivar from a +0 method, use
174 Expr *base = inner->IgnoreParenImpCasts();
175 while (isa<MemberExpr>(base))
176 base = cast<MemberExpr>(base)->getBase()->IgnoreParenImpCasts();
177 if (isa<ObjCIvarRefExpr>(base) &&
178 isa<ReturnStmt>(StmtMap->getParentIgnoreParenCasts(E))) {
179 if (ObjCMethodDecl *method = dyn_cast_or_null<ObjCMethodDecl>(ParentD)) {
180 if (!method->hasAttr<NSReturnsRetainedAttr>()) {
181 castToObjCObject(E, /*retained=*/false);
188 void castToObjCObject(CastExpr *E, bool retained) {
189 rewriteToBridgedCast(E, retained ? OBC_BridgeTransfer : OBC_Bridge);
192 void rewriteToBridgedCast(CastExpr *E, ObjCBridgeCastKind Kind) {
193 Transaction Trans(Pass.TA);
194 rewriteToBridgedCast(E, Kind, Trans);
197 void rewriteToBridgedCast(CastExpr *E, ObjCBridgeCastKind Kind,
198 Transaction &Trans) {
199 TransformActions &TA = Pass.TA;
201 // We will remove the compiler diagnostic.
202 if (!TA.hasDiagnostic(diag::err_arc_mismatched_cast,
203 diag::err_arc_cast_requires_bridge,
212 bridge = "__bridge "; break;
213 case OBC_BridgeTransfer:
214 bridge = "__bridge_transfer "; break;
215 case OBC_BridgeRetained:
216 bridge = "__bridge_retained "; break;
219 TA.clearDiagnostic(diag::err_arc_mismatched_cast,
220 diag::err_arc_cast_requires_bridge,
222 if (Kind == OBC_Bridge || !Pass.CFBridgingFunctionsDefined()) {
223 if (CStyleCastExpr *CCE = dyn_cast<CStyleCastExpr>(E)) {
224 TA.insertAfterToken(CCE->getLParenLoc(), bridge);
226 SourceLocation insertLoc = E->getSubExpr()->getLocStart();
227 SmallString<128> newCast;
230 newCast += E->getType().getAsString(Pass.Ctx.getPrintingPolicy());
233 if (isa<ParenExpr>(E->getSubExpr())) {
234 TA.insert(insertLoc, newCast.str());
237 TA.insert(insertLoc, newCast.str());
238 TA.insertAfterToken(E->getLocEnd(), ")");
242 assert(Kind == OBC_BridgeTransfer || Kind == OBC_BridgeRetained);
243 SmallString<32> BridgeCall;
245 Expr *WrapE = E->getSubExpr();
246 SourceLocation InsertLoc = WrapE->getLocStart();
248 SourceManager &SM = Pass.Ctx.getSourceManager();
249 char PrevChar = *SM.getCharacterData(InsertLoc.getLocWithOffset(-1));
250 if (Lexer::isIdentifierBodyChar(PrevChar, Pass.Ctx.getLangOpts()))
253 if (Kind == OBC_BridgeTransfer)
254 BridgeCall += "CFBridgingRelease";
256 BridgeCall += "CFBridgingRetain";
258 if (isa<ParenExpr>(WrapE)) {
259 TA.insert(InsertLoc, BridgeCall);
262 TA.insert(InsertLoc, BridgeCall);
263 TA.insertAfterToken(WrapE->getLocEnd(), ")");
268 void rewriteCastForCFRetain(CastExpr *castE, CallExpr *callE) {
269 Transaction Trans(Pass.TA);
270 Pass.TA.replace(callE->getSourceRange(), callE->getArg(0)->getSourceRange());
271 rewriteToBridgedCast(castE, OBC_BridgeRetained, Trans);
274 void getBlockMacroRanges(CastExpr *E, SourceRange &Outer, SourceRange &Inner) {
275 SourceManager &SM = Pass.Ctx.getSourceManager();
276 SourceLocation Loc = E->getExprLoc();
277 assert(Loc.isMacroID());
278 SourceLocation MacroBegin, MacroEnd;
279 llvm::tie(MacroBegin, MacroEnd) = SM.getImmediateExpansionRange(Loc);
280 SourceRange SubRange = E->getSubExpr()->IgnoreParenImpCasts()->getSourceRange();
281 SourceLocation InnerBegin = SM.getImmediateMacroCallerLoc(SubRange.getBegin());
282 SourceLocation InnerEnd = SM.getImmediateMacroCallerLoc(SubRange.getEnd());
284 Outer = SourceRange(MacroBegin, MacroEnd);
285 Inner = SourceRange(InnerBegin, InnerEnd);
288 void rewriteBlockCopyMacro(CastExpr *E) {
289 SourceRange OuterRange, InnerRange;
290 getBlockMacroRanges(E, OuterRange, InnerRange);
292 Transaction Trans(Pass.TA);
293 Pass.TA.replace(OuterRange, InnerRange);
294 Pass.TA.insert(InnerRange.getBegin(), "[");
295 Pass.TA.insertAfterToken(InnerRange.getEnd(), " copy]");
296 Pass.TA.clearDiagnostic(diag::err_arc_mismatched_cast,
297 diag::err_arc_cast_requires_bridge,
301 void removeBlockReleaseMacro(CastExpr *E) {
302 SourceRange OuterRange, InnerRange;
303 getBlockMacroRanges(E, OuterRange, InnerRange);
305 Transaction Trans(Pass.TA);
306 Pass.TA.clearDiagnostic(diag::err_arc_mismatched_cast,
307 diag::err_arc_cast_requires_bridge,
309 if (!hasSideEffects(E, Pass.Ctx)) {
310 if (tryRemoving(cast<Expr>(StmtMap->getParentIgnoreParenCasts(E))))
313 Pass.TA.replace(OuterRange, InnerRange);
316 bool tryRemoving(Expr *E) const {
318 Removables.reset(new ExprSet);
319 collectRemovables(Body, *Removables);
322 if (Removables->count(E)) {
323 Pass.TA.removeStmt(E);
330 void transformObjCToNonObjCCast(CastExpr *E) {
331 SourceLocation CastLoc = E->getExprLoc();
332 if (CastLoc.isMacroID()) {
333 StringRef MacroName = Lexer::getImmediateMacroName(CastLoc,
334 Pass.Ctx.getSourceManager(),
335 Pass.Ctx.getLangOpts());
336 if (MacroName == "Block_copy") {
337 rewriteBlockCopyMacro(E);
340 if (MacroName == "Block_release") {
341 removeBlockReleaseMacro(E);
346 if (isSelf(E->getSubExpr()))
347 return rewriteToBridgedCast(E, OBC_Bridge);
350 if (isPassedToCFRetain(E, callE))
351 return rewriteCastForCFRetain(E, callE);
353 ObjCMethodFamily family = getFamilyOfMessage(E->getSubExpr());
354 if (family == OMF_retain)
355 return rewriteToBridgedCast(E, OBC_BridgeRetained);
357 if (family == OMF_autorelease || family == OMF_release) {
358 std::string err = "it is not safe to cast to '";
359 err += E->getType().getAsString(Pass.Ctx.getPrintingPolicy());
360 err += "' the result of '";
361 err += family == OMF_autorelease ? "autorelease" : "release";
362 err += "' message; a __bridge cast may result in a pointer to a "
363 "destroyed object and a __bridge_retained may leak the object";
364 Pass.TA.reportError(err, E->getLocStart(),
365 E->getSubExpr()->getSourceRange());
368 parent = StmtMap->getParentIgnoreParenImpCasts(parent);
369 } while (parent && isa<ExprWithCleanups>(parent));
371 if (ReturnStmt *retS = dyn_cast_or_null<ReturnStmt>(parent)) {
372 std::string note = "remove the cast and change return type of function "
374 note += E->getSubExpr()->getType().getAsString(Pass.Ctx.getPrintingPolicy());
375 note += "' to have the object automatically autoreleased";
376 Pass.TA.reportNote(note, retS->getLocStart());
380 Expr *subExpr = E->getSubExpr();
382 // Look through pseudo-object expressions.
383 if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(subExpr)) {
384 subExpr = pseudo->getResultExpr();
385 assert(subExpr && "no result for pseudo-object of non-void type?");
388 if (ImplicitCastExpr *implCE = dyn_cast<ImplicitCastExpr>(subExpr)) {
389 if (implCE->getCastKind() == CK_ARCConsumeObject)
390 return rewriteToBridgedCast(E, OBC_BridgeRetained);
391 if (implCE->getCastKind() == CK_ARCReclaimReturnedObject)
392 return rewriteToBridgedCast(E, OBC_Bridge);
395 bool isConsumed = false;
396 if (isPassedToCParamWithKnownOwnership(E, isConsumed))
397 return rewriteToBridgedCast(E, isConsumed ? OBC_BridgeRetained
401 static ObjCMethodFamily getFamilyOfMessage(Expr *E) {
402 E = E->IgnoreParenCasts();
403 if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E))
404 return ME->getMethodFamily();
409 bool isPassedToCFRetain(Expr *E, CallExpr *&callE) const {
410 if ((callE = dyn_cast_or_null<CallExpr>(
411 StmtMap->getParentIgnoreParenImpCasts(E))))
413 FD = dyn_cast_or_null<FunctionDecl>(callE->getCalleeDecl()))
414 if (FD->getName() == "CFRetain" && FD->getNumParams() == 1 &&
415 FD->getParent()->isTranslationUnit() &&
416 FD->hasExternalLinkage())
422 bool isPassedToCParamWithKnownOwnership(Expr *E, bool &isConsumed) const {
423 if (CallExpr *callE = dyn_cast_or_null<CallExpr>(
424 StmtMap->getParentIgnoreParenImpCasts(E)))
426 FD = dyn_cast_or_null<FunctionDecl>(callE->getCalleeDecl())) {
428 for (unsigned e = callE->getNumArgs(); i != e; ++i) {
429 Expr *arg = callE->getArg(i);
430 if (arg == E || arg->IgnoreParenImpCasts() == E)
433 if (i < callE->getNumArgs() && i < FD->getNumParams()) {
434 ParmVarDecl *PD = FD->getParamDecl(i);
435 if (PD->getAttr<CFConsumedAttr>()) {
445 bool isSelf(Expr *E) const {
446 E = E->IgnoreParenLValueCasts();
447 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
448 if (ImplicitParamDecl *IPD = dyn_cast<ImplicitParamDecl>(DRE->getDecl()))
449 if (IPD->getIdentifier() == SelfII)
456 } // end anonymous namespace
458 void trans::rewriteUnbridgedCasts(MigrationPass &pass) {
459 BodyTransform<UnbridgedCastRewriter> trans(pass);
460 trans.TraverseDecl(pass.Ctx.getTranslationUnitDecl());