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-rw-r--r--clang/lib/ARCMigrate/TransRetainReleaseDealloc.cpp303
1 files changed, 303 insertions, 0 deletions
diff --git a/clang/lib/ARCMigrate/TransRetainReleaseDealloc.cpp b/clang/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
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--- /dev/null
+++ b/clang/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
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+//===--- TransRetainReleaseDealloc.cpp - Tranformations to ARC mode -------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// removeRetainReleaseDealloc:
+//
+// Removes retain/release/autorelease/dealloc messages.
+//
+// return [[foo retain] autorelease];
+// ---->
+// return foo;
+//
+//===----------------------------------------------------------------------===//
+
+#include "Transforms.h"
+#include "Internals.h"
+#include "clang/Sema/SemaDiagnostic.h"
+#include "clang/AST/ParentMap.h"
+#include "clang/Lex/Lexer.h"
+#include "clang/Basic/SourceManager.h"
+
+using namespace clang;
+using namespace arcmt;
+using namespace trans;
+
+namespace {
+
+class RetainReleaseDeallocRemover :
+ public RecursiveASTVisitor<RetainReleaseDeallocRemover> {
+ Stmt *Body;
+ MigrationPass &Pass;
+
+ ExprSet Removables;
+ OwningPtr<ParentMap> StmtMap;
+
+ Selector DelegateSel, FinalizeSel;
+
+public:
+ RetainReleaseDeallocRemover(MigrationPass &pass)
+ : Body(0), Pass(pass) {
+ DelegateSel =
+ Pass.Ctx.Selectors.getNullarySelector(&Pass.Ctx.Idents.get("delegate"));
+ FinalizeSel =
+ Pass.Ctx.Selectors.getNullarySelector(&Pass.Ctx.Idents.get("finalize"));
+ }
+
+ void transformBody(Stmt *body) {
+ Body = body;
+ collectRemovables(body, Removables);
+ StmtMap.reset(new ParentMap(body));
+ TraverseStmt(body);
+ }
+
+ bool VisitObjCMessageExpr(ObjCMessageExpr *E) {
+ switch (E->getMethodFamily()) {
+ default:
+ if (E->isInstanceMessage() && E->getSelector() == FinalizeSel)
+ break;
+ return true;
+ case OMF_autorelease:
+ if (isRemovable(E)) {
+ // An unused autorelease is badness. If we remove it the receiver
+ // will likely die immediately while previously it was kept alive
+ // by the autorelease pool. This is bad practice in general, leave it
+ // and emit an error to force the user to restructure his code.
+ Pass.TA.reportError("it is not safe to remove an unused 'autorelease' "
+ "message; its receiver may be destroyed immediately",
+ E->getLocStart(), E->getSourceRange());
+ return true;
+ }
+ // Pass through.
+ case OMF_retain:
+ case OMF_release:
+ if (E->getReceiverKind() == ObjCMessageExpr::Instance)
+ if (Expr *rec = E->getInstanceReceiver()) {
+ rec = rec->IgnoreParenImpCasts();
+ if (rec->getType().getObjCLifetime() == Qualifiers::OCL_ExplicitNone &&
+ (E->getMethodFamily() != OMF_retain || isRemovable(E))) {
+ std::string err = "it is not safe to remove '";
+ err += E->getSelector().getAsString() + "' message on "
+ "an __unsafe_unretained type";
+ Pass.TA.reportError(err, rec->getLocStart());
+ return true;
+ }
+
+ if (isGlobalVar(rec) &&
+ (E->getMethodFamily() != OMF_retain || isRemovable(E))) {
+ std::string err = "it is not safe to remove '";
+ err += E->getSelector().getAsString() + "' message on "
+ "a global variable";
+ Pass.TA.reportError(err, rec->getLocStart());
+ return true;
+ }
+
+ if (E->getMethodFamily() == OMF_release && isDelegateMessage(rec)) {
+ Pass.TA.reportError("it is not safe to remove 'retain' "
+ "message on the result of a 'delegate' message; "
+ "the object that was passed to 'setDelegate:' may not be "
+ "properly retained", rec->getLocStart());
+ return true;
+ }
+ }
+ case OMF_dealloc:
+ break;
+ }
+
+ switch (E->getReceiverKind()) {
+ default:
+ return true;
+ case ObjCMessageExpr::SuperInstance: {
+ Transaction Trans(Pass.TA);
+ clearDiagnostics(E->getSuperLoc());
+ if (tryRemoving(E))
+ return true;
+ Pass.TA.replace(E->getSourceRange(), "self");
+ return true;
+ }
+ case ObjCMessageExpr::Instance:
+ break;
+ }
+
+ Expr *rec = E->getInstanceReceiver();
+ if (!rec) return true;
+
+ Transaction Trans(Pass.TA);
+ clearDiagnostics(rec->getExprLoc());
+
+ ObjCMessageExpr *Msg = E;
+ Expr *RecContainer = Msg;
+ SourceRange RecRange = rec->getSourceRange();
+ checkForGCDOrXPC(Msg, RecContainer, rec, RecRange);
+
+ if (Msg->getMethodFamily() == OMF_release &&
+ isRemovable(RecContainer) && isInAtFinally(RecContainer)) {
+ // Change the -release to "receiver = nil" in a finally to avoid a leak
+ // when an exception is thrown.
+ Pass.TA.replace(RecContainer->getSourceRange(), RecRange);
+ std::string str = " = ";
+ str += getNilString(Pass.Ctx);
+ Pass.TA.insertAfterToken(RecRange.getEnd(), str);
+ return true;
+ }
+
+ if (!hasSideEffects(rec, Pass.Ctx)) {
+ if (tryRemoving(RecContainer))
+ return true;
+ }
+ Pass.TA.replace(RecContainer->getSourceRange(), RecRange);
+
+ return true;
+ }
+
+private:
+ /// \brief Check if the retain/release is due to a GCD/XPC macro that are
+ /// defined as:
+ ///
+ /// #define dispatch_retain(object) ({ dispatch_object_t _o = (object); _dispatch_object_validate(_o); (void)[_o retain]; })
+ /// #define dispatch_release(object) ({ dispatch_object_t _o = (object); _dispatch_object_validate(_o); [_o release]; })
+ /// #define xpc_retain(object) ({ xpc_object_t _o = (object); _xpc_object_validate(_o); [_o retain]; })
+ /// #define xpc_release(object) ({ xpc_object_t _o = (object); _xpc_object_validate(_o); [_o release]; })
+ ///
+ /// and return the top container which is the StmtExpr and the macro argument
+ /// expression.
+ void checkForGCDOrXPC(ObjCMessageExpr *Msg, Expr *&RecContainer,
+ Expr *&Rec, SourceRange &RecRange) {
+ SourceLocation Loc = Msg->getExprLoc();
+ if (!Loc.isMacroID())
+ return;
+ SourceManager &SM = Pass.Ctx.getSourceManager();
+ StringRef MacroName = Lexer::getImmediateMacroName(Loc, SM,
+ Pass.Ctx.getLangOpts());
+ bool isGCDOrXPC = llvm::StringSwitch<bool>(MacroName)
+ .Case("dispatch_retain", true)
+ .Case("dispatch_release", true)
+ .Case("xpc_retain", true)
+ .Case("xpc_release", true)
+ .Default(false);
+ if (!isGCDOrXPC)
+ return;
+
+ StmtExpr *StmtE = 0;
+ Stmt *S = Msg;
+ while (S) {
+ if (StmtExpr *SE = dyn_cast<StmtExpr>(S)) {
+ StmtE = SE;
+ break;
+ }
+ S = StmtMap->getParent(S);
+ }
+
+ if (!StmtE)
+ return;
+
+ Stmt::child_range StmtExprChild = StmtE->children();
+ if (!StmtExprChild)
+ return;
+ CompoundStmt *CompS = dyn_cast_or_null<CompoundStmt>(*StmtExprChild);
+ if (!CompS)
+ return;
+
+ Stmt::child_range CompStmtChild = CompS->children();
+ if (!CompStmtChild)
+ return;
+ DeclStmt *DeclS = dyn_cast_or_null<DeclStmt>(*CompStmtChild);
+ if (!DeclS)
+ return;
+ if (!DeclS->isSingleDecl())
+ return;
+ VarDecl *VD = dyn_cast_or_null<VarDecl>(DeclS->getSingleDecl());
+ if (!VD)
+ return;
+ Expr *Init = VD->getInit();
+ if (!Init)
+ return;
+
+ RecContainer = StmtE;
+ Rec = Init->IgnoreParenImpCasts();
+ if (ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Rec))
+ Rec = EWC->getSubExpr()->IgnoreParenImpCasts();
+ RecRange = Rec->getSourceRange();
+ if (SM.isMacroArgExpansion(RecRange.getBegin()))
+ RecRange.setBegin(SM.getImmediateSpellingLoc(RecRange.getBegin()));
+ if (SM.isMacroArgExpansion(RecRange.getEnd()))
+ RecRange.setEnd(SM.getImmediateSpellingLoc(RecRange.getEnd()));
+ }
+
+ void clearDiagnostics(SourceLocation loc) const {
+ Pass.TA.clearDiagnostic(diag::err_arc_illegal_explicit_message,
+ diag::err_unavailable,
+ diag::err_unavailable_message,
+ loc);
+ }
+
+ bool isDelegateMessage(Expr *E) const {
+ if (!E) return false;
+
+ E = E->IgnoreParenCasts();
+
+ // Also look through property-getter sugar.
+ if (PseudoObjectExpr *pseudoOp = dyn_cast<PseudoObjectExpr>(E))
+ E = pseudoOp->getResultExpr()->IgnoreImplicit();
+
+ if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E))
+ return (ME->isInstanceMessage() && ME->getSelector() == DelegateSel);
+
+ return false;
+ }
+
+ bool isInAtFinally(Expr *E) const {
+ assert(E);
+ Stmt *S = E;
+ while (S) {
+ if (isa<ObjCAtFinallyStmt>(S))
+ return true;
+ S = StmtMap->getParent(S);
+ }
+
+ return false;
+ }
+
+ bool isRemovable(Expr *E) const {
+ return Removables.count(E);
+ }
+
+ bool tryRemoving(Expr *E) const {
+ if (isRemovable(E)) {
+ Pass.TA.removeStmt(E);
+ return true;
+ }
+
+ Stmt *parent = StmtMap->getParent(E);
+
+ if (ImplicitCastExpr *castE = dyn_cast_or_null<ImplicitCastExpr>(parent))
+ return tryRemoving(castE);
+
+ if (ParenExpr *parenE = dyn_cast_or_null<ParenExpr>(parent))
+ return tryRemoving(parenE);
+
+ if (BinaryOperator *
+ bopE = dyn_cast_or_null<BinaryOperator>(parent)) {
+ if (bopE->getOpcode() == BO_Comma && bopE->getLHS() == E &&
+ isRemovable(bopE)) {
+ Pass.TA.replace(bopE->getSourceRange(), bopE->getRHS()->getSourceRange());
+ return true;
+ }
+ }
+
+ return false;
+ }
+
+};
+
+} // anonymous namespace
+
+void trans::removeRetainReleaseDeallocFinalize(MigrationPass &pass) {
+ BodyTransform<RetainReleaseDeallocRemover> trans(pass);
+ trans.TraverseDecl(pass.Ctx.getTranslationUnitDecl());
+}
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