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/__bridge_transfer 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 = (__bridge_transfer NSString *)
25 // 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/Sema/SemaDiagnostic.h"
39 #include "clang/AST/ParentMap.h"
40 #include "clang/Basic/SourceManager.h"
42 using namespace clang;
43 using namespace arcmt;
44 using namespace trans;
48 class UnbridgedCastRewriter : public RecursiveASTVisitor<UnbridgedCastRewriter>{
50 IdentifierInfo *SelfII;
51 llvm::OwningPtr<ParentMap> StmtMap;
54 UnbridgedCastRewriter(MigrationPass &pass) : Pass(pass) {
55 SelfII = &Pass.Ctx.Idents.get("self");
58 void transformBody(Stmt *body) {
59 StmtMap.reset(new ParentMap(body));
63 bool VisitCastExpr(CastExpr *E) {
64 if (E->getCastKind() != CK_CPointerToObjCPointerCast
65 && E->getCastKind() != CK_BitCast)
68 QualType castType = E->getType();
69 Expr *castExpr = E->getSubExpr();
70 QualType castExprType = castExpr->getType();
72 if (castType->isObjCObjectPointerType() &&
73 castExprType->isObjCObjectPointerType())
75 if (!castType->isObjCObjectPointerType() &&
76 !castExprType->isObjCObjectPointerType())
79 bool exprRetainable = castExprType->isObjCIndirectLifetimeType();
80 bool castRetainable = castType->isObjCIndirectLifetimeType();
81 if (exprRetainable == castRetainable) return true;
83 if (castExpr->isNullPointerConstant(Pass.Ctx,
84 Expr::NPC_ValueDependentIsNull))
87 SourceLocation loc = castExpr->getExprLoc();
88 if (loc.isValid() && Pass.Ctx.getSourceManager().isInSystemHeader(loc))
91 if (castType->isObjCObjectPointerType())
92 transformNonObjCToObjCCast(E);
94 transformObjCToNonObjCCast(E);
100 void transformNonObjCToObjCCast(CastExpr *E) {
103 // Global vars are assumed that are cast as unretained.
105 if (E->getSubExpr()->getType()->isPointerType()) {
106 castToObjCObject(E, /*retained=*/false);
110 // If the cast is directly over the result of a Core Foundation function
111 // try to figure out whether it should be cast as retained or unretained.
112 Expr *inner = E->IgnoreParenCasts();
113 if (CallExpr *callE = dyn_cast<CallExpr>(inner)) {
114 if (FunctionDecl *FD = callE->getDirectCallee()) {
115 if (FD->getAttr<CFReturnsRetainedAttr>()) {
116 castToObjCObject(E, /*retained=*/true);
119 if (FD->getAttr<CFReturnsNotRetainedAttr>()) {
120 castToObjCObject(E, /*retained=*/false);
123 if (FD->isGlobal() &&
124 FD->getIdentifier() &&
125 ento::cocoa::isRefType(E->getSubExpr()->getType(), "CF",
126 FD->getIdentifier()->getName())) {
127 StringRef fname = FD->getIdentifier()->getName();
128 if (fname.endswith("Retain") ||
129 fname.find("Create") != StringRef::npos ||
130 fname.find("Copy") != StringRef::npos) {
131 castToObjCObject(E, /*retained=*/true);
135 if (fname.find("Get") != StringRef::npos) {
136 castToObjCObject(E, /*retained=*/false);
144 void castToObjCObject(CastExpr *E, bool retained) {
145 rewriteToBridgedCast(E, retained ? OBC_BridgeTransfer : OBC_Bridge);
148 void rewriteToBridgedCast(CastExpr *E, ObjCBridgeCastKind Kind) {
149 Transaction Trans(Pass.TA);
150 rewriteToBridgedCast(E, Kind, Trans);
153 void rewriteToBridgedCast(CastExpr *E, ObjCBridgeCastKind Kind,
154 Transaction &Trans) {
155 TransformActions &TA = Pass.TA;
157 // We will remove the compiler diagnostic.
158 if (!TA.hasDiagnostic(diag::err_arc_mismatched_cast,
159 diag::err_arc_cast_requires_bridge,
168 bridge = "__bridge "; break;
169 case OBC_BridgeTransfer:
170 bridge = "__bridge_transfer "; break;
171 case OBC_BridgeRetained:
172 bridge = "__bridge_retained "; break;
175 TA.clearDiagnostic(diag::err_arc_mismatched_cast,
176 diag::err_arc_cast_requires_bridge,
178 if (CStyleCastExpr *CCE = dyn_cast<CStyleCastExpr>(E)) {
179 TA.insertAfterToken(CCE->getLParenLoc(), bridge);
181 SourceLocation insertLoc = E->getSubExpr()->getLocStart();
182 llvm::SmallString<128> newCast;
185 newCast += E->getType().getAsString(Pass.Ctx.getPrintingPolicy());
188 if (isa<ParenExpr>(E->getSubExpr())) {
189 TA.insert(insertLoc, newCast.str());
192 TA.insert(insertLoc, newCast.str());
193 TA.insertAfterToken(E->getLocEnd(), ")");
198 void rewriteCastForCFRetain(CastExpr *castE, CallExpr *callE) {
199 Transaction Trans(Pass.TA);
200 Pass.TA.replace(callE->getSourceRange(), callE->getArg(0)->getSourceRange());
201 rewriteToBridgedCast(castE, OBC_BridgeRetained, Trans);
204 void transformObjCToNonObjCCast(CastExpr *E) {
205 if (isSelf(E->getSubExpr()))
206 return rewriteToBridgedCast(E, OBC_Bridge);
209 if (isPassedToCFRetain(E, callE))
210 return rewriteCastForCFRetain(E, callE);
212 ObjCMethodFamily family = getFamilyOfMessage(E->getSubExpr());
213 if (family == OMF_retain)
214 return rewriteToBridgedCast(E, OBC_BridgeRetained);
216 if (family == OMF_autorelease || family == OMF_release) {
217 std::string err = "it is not safe to cast to '";
218 err += E->getType().getAsString(Pass.Ctx.getPrintingPolicy());
219 err += "' the result of '";
220 err += family == OMF_autorelease ? "autorelease" : "release";
221 err += "' message; a __bridge cast may result in a pointer to a "
222 "destroyed object and a __bridge_retained may leak the object";
223 Pass.TA.reportError(err, E->getLocStart(),
224 E->getSubExpr()->getSourceRange());
227 parent = StmtMap->getParentIgnoreParenImpCasts(parent);
228 } while (parent && isa<ExprWithCleanups>(parent));
230 if (ReturnStmt *retS = dyn_cast_or_null<ReturnStmt>(parent)) {
231 std::string note = "remove the cast and change return type of function "
233 note += E->getSubExpr()->getType().getAsString(Pass.Ctx.getPrintingPolicy());
234 note += "' to have the object automatically autoreleased";
235 Pass.TA.reportNote(note, retS->getLocStart());
239 if (ImplicitCastExpr *implCE = dyn_cast<ImplicitCastExpr>(E->getSubExpr())){
240 if (implCE->getCastKind() == CK_ARCConsumeObject)
241 return rewriteToBridgedCast(E, OBC_BridgeRetained);
242 if (implCE->getCastKind() == CK_ARCReclaimReturnedObject)
243 return rewriteToBridgedCast(E, OBC_Bridge);
246 bool isConsumed = false;
247 if (isPassedToCParamWithKnownOwnership(E, isConsumed))
248 return rewriteToBridgedCast(E, isConsumed ? OBC_BridgeRetained
252 static ObjCMethodFamily getFamilyOfMessage(Expr *E) {
253 E = E->IgnoreParenCasts();
254 if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E))
255 return ME->getMethodFamily();
260 bool isPassedToCFRetain(Expr *E, CallExpr *&callE) const {
261 if ((callE = dyn_cast_or_null<CallExpr>(
262 StmtMap->getParentIgnoreParenImpCasts(E))))
264 FD = dyn_cast_or_null<FunctionDecl>(callE->getCalleeDecl()))
265 if (FD->getName() == "CFRetain" && FD->getNumParams() == 1 &&
266 FD->getParent()->isTranslationUnit() &&
267 FD->getLinkage() == ExternalLinkage)
273 bool isPassedToCParamWithKnownOwnership(Expr *E, bool &isConsumed) const {
274 if (CallExpr *callE = dyn_cast_or_null<CallExpr>(
275 StmtMap->getParentIgnoreParenImpCasts(E)))
277 FD = dyn_cast_or_null<FunctionDecl>(callE->getCalleeDecl())) {
279 for (unsigned e = callE->getNumArgs(); i != e; ++i) {
280 Expr *arg = callE->getArg(i);
281 if (arg == E || arg->IgnoreParenImpCasts() == E)
284 if (i < callE->getNumArgs()) {
285 ParmVarDecl *PD = FD->getParamDecl(i);
286 if (PD->getAttr<CFConsumedAttr>()) {
296 bool isSelf(Expr *E) const {
297 E = E->IgnoreParenLValueCasts();
298 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
299 if (ImplicitParamDecl *IPD = dyn_cast<ImplicitParamDecl>(DRE->getDecl()))
300 if (IPD->getIdentifier() == SelfII)
307 } // end anonymous namespace
309 void trans::rewriteUnbridgedCasts(MigrationPass &pass) {
310 BodyTransform<UnbridgedCastRewriter> trans(pass);
311 trans.TraverseDecl(pass.Ctx.getTranslationUnitDecl());