maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[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

llvm-svn: 315261
This commit is contained in:
Akira Hatanaka 2017-10-10 01:24:33 +00:00
parent 1301a878f1
commit cc7171abbf
2 changed files with 32 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
clang/lib/Sema/SemaExprObjC.cpp
View File

@ -4317,14 +4317,37 @@ bool Sema::CheckObjCARCUnavailableWeakConversion(QualType castType,
/// 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)
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;
}

1
clang/test/CodeGenObjC/arc-bridged-cast.m
View File

@ -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;
}