2011-06-22 04:20:39 +08:00
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//===--- TransRetainReleaseDealloc.cpp - Tranformations to ARC mode -------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// removeRetainReleaseDealloc:
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//
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// Removes retain/release/autorelease/dealloc messages.
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//
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// return [[foo retain] autorelease];
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// ---->
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// return foo;
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//
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//===----------------------------------------------------------------------===//
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#include "Transforms.h"
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#include "Internals.h"
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#include "clang/Sema/SemaDiagnostic.h"
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#include "clang/AST/ParentMap.h"
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using namespace clang;
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using namespace arcmt;
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using namespace trans;
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using llvm::StringRef;
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namespace {
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class RetainReleaseDeallocRemover :
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public RecursiveASTVisitor<RetainReleaseDeallocRemover> {
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Stmt *Body;
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MigrationPass &Pass;
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ExprSet Removables;
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llvm::OwningPtr<ParentMap> StmtMap;
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public:
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2011-06-24 05:21:33 +08:00
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RetainReleaseDeallocRemover(MigrationPass &pass)
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: Body(0), Pass(pass) { }
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2011-06-22 04:20:39 +08:00
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void transformBody(Stmt *body) {
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Body = body;
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collectRemovables(body, Removables);
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StmtMap.reset(new ParentMap(body));
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TraverseStmt(body);
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}
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bool VisitObjCMessageExpr(ObjCMessageExpr *E) {
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switch (E->getMethodFamily()) {
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default:
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return true;
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2011-07-15 05:26:49 +08:00
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case OMF_autorelease:
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if (isRemovable(E)) {
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// An unused autorelease is badness. If we remove it the receiver
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// will likely die immediately while previously it was kept alive
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// by the autorelease pool. This is bad practice in general, leave it
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// and emit an error to force the user to restructure his code.
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std::string err = "it is not safe to remove an unused '";
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err += E->getSelector().getAsString() + "'; its receiver may be "
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"destroyed immediately";
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Pass.TA.reportError(err, E->getLocStart(), E->getSourceRange());
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return true;
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}
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// Pass through.
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2011-06-22 04:20:39 +08:00
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case OMF_retain:
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case OMF_release:
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if (E->getReceiverKind() == ObjCMessageExpr::Instance)
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if (Expr *rec = E->getInstanceReceiver()) {
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rec = rec->IgnoreParenImpCasts();
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2011-07-15 06:46:12 +08:00
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if (rec->getType().getObjCLifetime() == Qualifiers::OCL_ExplicitNone &&
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(E->getMethodFamily() != OMF_retain || isRemovable(E))) {
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2011-07-15 05:26:49 +08:00
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std::string err = "it is not safe to remove '";
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2011-06-22 04:20:39 +08:00
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err += E->getSelector().getAsString() + "' message on "
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"an __unsafe_unretained type";
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Pass.TA.reportError(err, rec->getLocStart());
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return true;
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}
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2011-07-15 07:32:04 +08:00
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if (isGlobalVar(rec) &&
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(E->getMethodFamily() != OMF_retain || isRemovable(E))) {
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std::string err = "it is not safe to remove '";
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err += E->getSelector().getAsString() + "' message on "
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"a global variable";
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Pass.TA.reportError(err, rec->getLocStart());
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return true;
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}
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2011-06-22 04:20:39 +08:00
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}
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case OMF_dealloc:
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break;
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}
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switch (E->getReceiverKind()) {
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default:
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return true;
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case ObjCMessageExpr::SuperInstance: {
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Transaction Trans(Pass.TA);
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2011-07-16 05:11:23 +08:00
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clearDiagnostics(E->getSuperLoc());
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2011-06-22 04:20:39 +08:00
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if (tryRemoving(E))
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return true;
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Pass.TA.replace(E->getSourceRange(), "self");
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return true;
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}
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case ObjCMessageExpr::Instance:
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break;
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}
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Expr *rec = E->getInstanceReceiver();
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if (!rec) return true;
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Transaction Trans(Pass.TA);
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2011-07-16 05:11:23 +08:00
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clearDiagnostics(rec->getExprLoc());
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if (E->getMethodFamily() == OMF_release &&
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isRemovable(E) && isInAtFinally(E)) {
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// Change the -release to "receiver = 0" in a finally to avoid a leak
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// when an exception is thrown.
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Pass.TA.replace(E->getSourceRange(), rec->getSourceRange());
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Pass.TA.insertAfterToken(rec->getLocEnd(), " = 0");
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return true;
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}
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2011-06-22 04:20:39 +08:00
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if (!hasSideEffects(E, Pass.Ctx)) {
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if (tryRemoving(E))
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return true;
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}
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Pass.TA.replace(E->getSourceRange(), rec->getSourceRange());
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return true;
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}
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private:
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2011-07-16 05:11:23 +08:00
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void clearDiagnostics(SourceLocation loc) const {
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Pass.TA.clearDiagnostic(diag::err_arc_illegal_explicit_message,
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diag::err_unavailable,
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diag::err_unavailable_message,
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loc);
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}
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bool isInAtFinally(Expr *E) const {
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assert(E);
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Stmt *S = E;
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while (S) {
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if (isa<ObjCAtFinallyStmt>(S))
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return true;
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S = StmtMap->getParent(S);
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}
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return false;
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}
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2011-06-22 04:20:39 +08:00
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bool isRemovable(Expr *E) const {
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return Removables.count(E);
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}
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bool tryRemoving(Expr *E) const {
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if (isRemovable(E)) {
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Pass.TA.removeStmt(E);
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return true;
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}
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2011-07-07 14:58:02 +08:00
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Stmt *parent = StmtMap->getParent(E);
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if (ImplicitCastExpr *castE = dyn_cast_or_null<ImplicitCastExpr>(parent))
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return tryRemoving(castE);
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if (ParenExpr *parenE = dyn_cast_or_null<ParenExpr>(parent))
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2011-06-22 04:20:39 +08:00
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return tryRemoving(parenE);
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if (BinaryOperator *
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2011-07-07 14:58:02 +08:00
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bopE = dyn_cast_or_null<BinaryOperator>(parent)) {
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2011-06-22 04:20:39 +08:00
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if (bopE->getOpcode() == BO_Comma && bopE->getLHS() == E &&
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isRemovable(bopE)) {
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Pass.TA.replace(bopE->getSourceRange(), bopE->getRHS()->getSourceRange());
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return true;
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}
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}
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return false;
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}
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};
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} // anonymous namespace
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void trans::removeRetainReleaseDealloc(MigrationPass &pass) {
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BodyTransform<RetainReleaseDeallocRemover> trans(pass);
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trans.TraverseDecl(pass.Ctx.getTranslationUnitDecl());
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}
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