1 //===--- TransUnbridgedCasts.cpp - Tranformations 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 //===----------------------------------------------------------------------===//
35 #include "Transforms.h"
36 #include "Internals.h"
37 #include "clang/Analysis/DomainSpecific/CocoaConventions.h"
38 #include "clang/AST/ASTContext.h"
39 #include "clang/AST/ParentMap.h"
40 #include "clang/Basic/SourceManager.h"
41 #include "clang/Lex/Lexer.h"
42 #include "clang/Sema/SemaDiagnostic.h"
43 #include "llvm/ADT/SmallString.h"
45 using namespace clang;
46 using namespace arcmt;
47 using namespace trans;
51 class UnbridgedCastRewriter : public RecursiveASTVisitor<UnbridgedCastRewriter>{
53 IdentifierInfo *SelfII;
54 OwningPtr<ParentMap> StmtMap;
58 UnbridgedCastRewriter(MigrationPass &pass) : Pass(pass), ParentD(0) {
59 SelfII = &Pass.Ctx.Idents.get("self");
62 void transformBody(Stmt *body, Decl *ParentD) {
63 this->ParentD = ParentD;
64 StmtMap.reset(new ParentMap(body));
68 bool VisitCastExpr(CastExpr *E) {
69 if (E->getCastKind() != CK_CPointerToObjCPointerCast
70 && E->getCastKind() != CK_BitCast)
73 QualType castType = E->getType();
74 Expr *castExpr = E->getSubExpr();
75 QualType castExprType = castExpr->getType();
77 if (castType->isObjCObjectPointerType() &&
78 castExprType->isObjCObjectPointerType())
80 if (!castType->isObjCObjectPointerType() &&
81 !castExprType->isObjCObjectPointerType())
84 bool exprRetainable = castExprType->isObjCIndirectLifetimeType();
85 bool castRetainable = castType->isObjCIndirectLifetimeType();
86 if (exprRetainable == castRetainable) return true;
88 if (castExpr->isNullPointerConstant(Pass.Ctx,
89 Expr::NPC_ValueDependentIsNull))
92 SourceLocation loc = castExpr->getExprLoc();
93 if (loc.isValid() && Pass.Ctx.getSourceManager().isInSystemHeader(loc))
96 if (castType->isObjCObjectPointerType())
97 transformNonObjCToObjCCast(E);
99 transformObjCToNonObjCCast(E);
105 void transformNonObjCToObjCCast(CastExpr *E) {
108 // Global vars are assumed that are cast as unretained.
110 if (E->getSubExpr()->getType()->isPointerType()) {
111 castToObjCObject(E, /*retained=*/false);
115 // If the cast is directly over the result of a Core Foundation function
116 // try to figure out whether it should be cast as retained or unretained.
117 Expr *inner = E->IgnoreParenCasts();
118 if (CallExpr *callE = dyn_cast<CallExpr>(inner)) {
119 if (FunctionDecl *FD = callE->getDirectCallee()) {
120 if (FD->getAttr<CFReturnsRetainedAttr>()) {
121 castToObjCObject(E, /*retained=*/true);
124 if (FD->getAttr<CFReturnsNotRetainedAttr>()) {
125 castToObjCObject(E, /*retained=*/false);
128 if (FD->isGlobal() &&
129 FD->getIdentifier() &&
130 ento::cocoa::isRefType(E->getSubExpr()->getType(), "CF",
131 FD->getIdentifier()->getName())) {
132 StringRef fname = FD->getIdentifier()->getName();
133 if (fname.endswith("Retain") ||
134 fname.find("Create") != StringRef::npos ||
135 fname.find("Copy") != StringRef::npos) {
136 // Do not migrate to couple of bridge transfer casts which
137 // cancel each other out. Leave it unchanged so error gets user
138 // attention instead.
139 if (FD->getName() == "CFRetain" &&
140 FD->getNumParams() == 1 &&
141 FD->getParent()->isTranslationUnit() &&
142 FD->getLinkage() == ExternalLinkage) {
143 Expr *Arg = callE->getArg(0);
144 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) {
145 const Expr *sub = ICE->getSubExpr();
146 QualType T = sub->getType();
147 if (T->isObjCObjectPointerType())
151 castToObjCObject(E, /*retained=*/true);
155 if (fname.find("Get") != StringRef::npos) {
156 castToObjCObject(E, /*retained=*/false);
163 // If returning an ivar or a member of an ivar from a +0 method, use
165 Expr *base = inner->IgnoreParenImpCasts();
166 while (isa<MemberExpr>(base))
167 base = cast<MemberExpr>(base)->getBase()->IgnoreParenImpCasts();
168 if (isa<ObjCIvarRefExpr>(base) &&
169 isa<ReturnStmt>(StmtMap->getParentIgnoreParenCasts(E))) {
170 if (ObjCMethodDecl *method = dyn_cast_or_null<ObjCMethodDecl>(ParentD)) {
171 if (!method->hasAttr<NSReturnsRetainedAttr>()) {
172 castToObjCObject(E, /*retained=*/false);
179 void castToObjCObject(CastExpr *E, bool retained) {
180 rewriteToBridgedCast(E, retained ? OBC_BridgeTransfer : OBC_Bridge);
183 void rewriteToBridgedCast(CastExpr *E, ObjCBridgeCastKind Kind) {
184 Transaction Trans(Pass.TA);
185 rewriteToBridgedCast(E, Kind, Trans);
188 void rewriteToBridgedCast(CastExpr *E, ObjCBridgeCastKind Kind,
189 Transaction &Trans) {
190 TransformActions &TA = Pass.TA;
192 // We will remove the compiler diagnostic.
193 if (!TA.hasDiagnostic(diag::err_arc_mismatched_cast,
194 diag::err_arc_cast_requires_bridge,
203 bridge = "__bridge "; break;
204 case OBC_BridgeTransfer:
205 bridge = "__bridge_transfer "; break;
206 case OBC_BridgeRetained:
207 bridge = "__bridge_retained "; break;
210 TA.clearDiagnostic(diag::err_arc_mismatched_cast,
211 diag::err_arc_cast_requires_bridge,
213 if (Kind == OBC_Bridge || !Pass.CFBridgingFunctionsDefined()) {
214 if (CStyleCastExpr *CCE = dyn_cast<CStyleCastExpr>(E)) {
215 TA.insertAfterToken(CCE->getLParenLoc(), bridge);
217 SourceLocation insertLoc = E->getSubExpr()->getLocStart();
218 SmallString<128> newCast;
221 newCast += E->getType().getAsString(Pass.Ctx.getPrintingPolicy());
224 if (isa<ParenExpr>(E->getSubExpr())) {
225 TA.insert(insertLoc, newCast.str());
228 TA.insert(insertLoc, newCast.str());
229 TA.insertAfterToken(E->getLocEnd(), ")");
233 assert(Kind == OBC_BridgeTransfer || Kind == OBC_BridgeRetained);
234 SmallString<32> BridgeCall;
236 Expr *WrapE = E->getSubExpr();
237 SourceLocation InsertLoc = WrapE->getLocStart();
239 SourceManager &SM = Pass.Ctx.getSourceManager();
240 char PrevChar = *SM.getCharacterData(InsertLoc.getLocWithOffset(-1));
241 if (Lexer::isIdentifierBodyChar(PrevChar, Pass.Ctx.getLangOpts()))
244 if (Kind == OBC_BridgeTransfer)
245 BridgeCall += "CFBridgingRelease";
247 BridgeCall += "CFBridgingRetain";
249 if (isa<ParenExpr>(WrapE)) {
250 TA.insert(InsertLoc, BridgeCall);
253 TA.insert(InsertLoc, BridgeCall);
254 TA.insertAfterToken(WrapE->getLocEnd(), ")");
259 void rewriteCastForCFRetain(CastExpr *castE, CallExpr *callE) {
260 Transaction Trans(Pass.TA);
261 Pass.TA.replace(callE->getSourceRange(), callE->getArg(0)->getSourceRange());
262 rewriteToBridgedCast(castE, OBC_BridgeRetained, Trans);
265 void transformObjCToNonObjCCast(CastExpr *E) {
266 if (isSelf(E->getSubExpr()))
267 return rewriteToBridgedCast(E, OBC_Bridge);
270 if (isPassedToCFRetain(E, callE))
271 return rewriteCastForCFRetain(E, callE);
273 ObjCMethodFamily family = getFamilyOfMessage(E->getSubExpr());
274 if (family == OMF_retain)
275 return rewriteToBridgedCast(E, OBC_BridgeRetained);
277 if (family == OMF_autorelease || family == OMF_release) {
278 std::string err = "it is not safe to cast to '";
279 err += E->getType().getAsString(Pass.Ctx.getPrintingPolicy());
280 err += "' the result of '";
281 err += family == OMF_autorelease ? "autorelease" : "release";
282 err += "' message; a __bridge cast may result in a pointer to a "
283 "destroyed object and a __bridge_retained may leak the object";
284 Pass.TA.reportError(err, E->getLocStart(),
285 E->getSubExpr()->getSourceRange());
288 parent = StmtMap->getParentIgnoreParenImpCasts(parent);
289 } while (parent && isa<ExprWithCleanups>(parent));
291 if (ReturnStmt *retS = dyn_cast_or_null<ReturnStmt>(parent)) {
292 std::string note = "remove the cast and change return type of function "
294 note += E->getSubExpr()->getType().getAsString(Pass.Ctx.getPrintingPolicy());
295 note += "' to have the object automatically autoreleased";
296 Pass.TA.reportNote(note, retS->getLocStart());
300 Expr *subExpr = E->getSubExpr();
302 // Look through pseudo-object expressions.
303 if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(subExpr)) {
304 subExpr = pseudo->getResultExpr();
305 assert(subExpr && "no result for pseudo-object of non-void type?");
308 if (ImplicitCastExpr *implCE = dyn_cast<ImplicitCastExpr>(subExpr)) {
309 if (implCE->getCastKind() == CK_ARCConsumeObject)
310 return rewriteToBridgedCast(E, OBC_BridgeRetained);
311 if (implCE->getCastKind() == CK_ARCReclaimReturnedObject)
312 return rewriteToBridgedCast(E, OBC_Bridge);
315 bool isConsumed = false;
316 if (isPassedToCParamWithKnownOwnership(E, isConsumed))
317 return rewriteToBridgedCast(E, isConsumed ? OBC_BridgeRetained
321 static ObjCMethodFamily getFamilyOfMessage(Expr *E) {
322 E = E->IgnoreParenCasts();
323 if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E))
324 return ME->getMethodFamily();
329 bool isPassedToCFRetain(Expr *E, CallExpr *&callE) const {
330 if ((callE = dyn_cast_or_null<CallExpr>(
331 StmtMap->getParentIgnoreParenImpCasts(E))))
333 FD = dyn_cast_or_null<FunctionDecl>(callE->getCalleeDecl()))
334 if (FD->getName() == "CFRetain" && FD->getNumParams() == 1 &&
335 FD->getParent()->isTranslationUnit() &&
336 FD->getLinkage() == ExternalLinkage)
342 bool isPassedToCParamWithKnownOwnership(Expr *E, bool &isConsumed) const {
343 if (CallExpr *callE = dyn_cast_or_null<CallExpr>(
344 StmtMap->getParentIgnoreParenImpCasts(E)))
346 FD = dyn_cast_or_null<FunctionDecl>(callE->getCalleeDecl())) {
348 for (unsigned e = callE->getNumArgs(); i != e; ++i) {
349 Expr *arg = callE->getArg(i);
350 if (arg == E || arg->IgnoreParenImpCasts() == E)
353 if (i < callE->getNumArgs()) {
354 ParmVarDecl *PD = FD->getParamDecl(i);
355 if (PD->getAttr<CFConsumedAttr>()) {
365 bool isSelf(Expr *E) const {
366 E = E->IgnoreParenLValueCasts();
367 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
368 if (ImplicitParamDecl *IPD = dyn_cast<ImplicitParamDecl>(DRE->getDecl()))
369 if (IPD->getIdentifier() == SelfII)
376 } // end anonymous namespace
378 void trans::rewriteUnbridgedCasts(MigrationPass &pass) {
379 BodyTransform<UnbridgedCastRewriter> trans(pass);
380 trans.TraverseDecl(pass.Ctx.getTranslationUnitDecl());