Author: ahatanak Date: Mon Oct 9 18:24:33 2017 New Revision: 315261 URL: http://llvm.org/viewvc/llvm-project?rev=315261&view=rev Log: [Sema][ObjC] Preserve syntactic sugar when removing ARCReclaimReturnedObject cast.
This is a follow-up to r314370. Rather than throwing away the enclosing parentheses, this commit walks down the expression until an ARCReclaimReturnedObject cast is found and removes just the cast, preserving the syntactic sugar expressions (parens and casts) that were visited up to that point. rdar://problem/34705720 Differential Revision: https://reviews.llvm.org/D38659 Modified: cfe/trunk/lib/Sema/SemaExprObjC.cpp cfe/trunk/test/CodeGenObjC/arc-bridged-cast.m Modified: cfe/trunk/lib/Sema/SemaExprObjC.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprObjC.cpp?rev=315261&r1=315260&r2=315261&view=diff ============================================================================== --- cfe/trunk/lib/Sema/SemaExprObjC.cpp (original) +++ cfe/trunk/lib/Sema/SemaExprObjC.cpp Mon Oct 9 18:24:33 2017 @@ -4317,14 +4317,37 @@ bool Sema::CheckObjCARCUnavailableWeakCo /// Look for an ObjCReclaimReturnedObject cast and destroy it. static Expr *maybeUndoReclaimObject(Expr *e) { - // For now, we just undo operands that are *immediately* reclaim - // expressions, which prevents the vast majority of potential - // problems here. To catch them all, we'd need to rebuild arbitrary - // value-propagating subexpressions --- we can't reliably rebuild - // in-place because of expression sharing. - if (auto *ice = dyn_cast<ImplicitCastExpr>(e->IgnoreParens())) - if (ice->getCastKind() == CK_ARCReclaimReturnedObject) - return ice->getSubExpr(); + Expr *curExpr = e, *prevExpr = nullptr; + + // Walk down the expression until we hit an implicit cast of kind + // ARCReclaimReturnedObject or an Expr that is neither a Paren nor a Cast. + while (true) { + if (auto *pe = dyn_cast<ParenExpr>(curExpr)) { + prevExpr = curExpr; + curExpr = pe->getSubExpr(); + continue; + } + + if (auto *ce = dyn_cast<CastExpr>(curExpr)) { + if (auto *ice = dyn_cast<ImplicitCastExpr>(ce)) + if (ice->getCastKind() == CK_ARCReclaimReturnedObject) { + if (!prevExpr) + return ice->getSubExpr(); + if (auto *pe = dyn_cast<ParenExpr>(prevExpr)) + pe->setSubExpr(ice->getSubExpr()); + else + cast<CastExpr>(prevExpr)->setSubExpr(ice->getSubExpr()); + return e; + } + + prevExpr = curExpr; + curExpr = ce->getSubExpr(); + continue; + } + + // Break out of the loop if curExpr is neither a Paren nor a Cast. + break; + } return e; } Modified: cfe/trunk/test/CodeGenObjC/arc-bridged-cast.m URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenObjC/arc-bridged-cast.m?rev=315261&r1=315260&r2=315261&view=diff ============================================================================== --- cfe/trunk/test/CodeGenObjC/arc-bridged-cast.m (original) +++ cfe/trunk/test/CodeGenObjC/arc-bridged-cast.m Mon Oct 9 18:24:33 2017 @@ -102,5 +102,6 @@ CFStringRef bridge_of_paren_expr() { // CHECK-NOT: call i8* @objc_retainAutoreleasedReturnValue( // CHECK-NOT: call void @objc_release( CFStringRef r = (__bridge CFStringRef)(CreateNSString()); + r = (__bridge CFStringRef)((NSString *)(CreateNSString())); return r; } _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
