[objcmt] When rewriting to subscripting syntax, make sure we put

the receiver in parentheses when necessary.

Part of rdar://11438360

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@156789 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 30 insertions, 2 deletions

diff --git a/lib/Edit/RewriteObjCFoundationAPI.cpp b/lib/Edit/RewriteObjCFoundationAPI.cpp
index 8c3c7a5bf3..218ef2274f 100644
--- a/lib/Edit/RewriteObjCFoundationAPI.cpp
+++ b/lib/Edit/RewriteObjCFoundationAPI.cpp
@@ -77,9 +77,10 @@ bool edit::rewriteObjCRedundantCallWithLiteral(const ObjCMessageExpr *Msg,
 // rewriteToObjCSubscriptSyntax.
 //===----------------------------------------------------------------------===//
 
+static bool subscriptOperatorNeedsParens(const Expr *FullExpr);
+
 static void maybePutParensOnReceiver(const Expr *Receiver, Commit &commit) {
-  Receiver = Receiver->IgnoreImpCasts();
-  if (isa<BinaryOperator>(Receiver) || isa<UnaryOperator>(Receiver)) {
+  if (subscriptOperatorNeedsParens(Receiver)) {
     SourceRange RecRange = Receiver->getSourceRange();
     commit.insertWrap("(", RecRange, ")");
   }
@@ -600,6 +601,29 @@ static bool rewriteToNumberLiteral(const ObjCMessageExpr *Msg,
   return true;
 }
 
+// FIXME: Make determination of operator precedence more general and
+// make it broadly available.
+static bool subscriptOperatorNeedsParens(const Expr *FullExpr) {
+  const Expr* Expr = FullExpr->IgnoreImpCasts();
+  if (isa<ArraySubscriptExpr>(Expr) ||
+      isa<CallExpr>(Expr) ||
+      isa<DeclRefExpr>(Expr) ||
+      isa<CXXNamedCastExpr>(Expr) ||
+      isa<CXXConstructExpr>(Expr) ||
+      isa<CXXThisExpr>(Expr) ||
+      isa<CXXTypeidExpr>(Expr) ||
+      isa<CXXUnresolvedConstructExpr>(Expr) ||
+      isa<ObjCMessageExpr>(Expr) ||
+      isa<ObjCPropertyRefExpr>(Expr) ||
+      isa<ObjCProtocolExpr>(Expr) ||
+      isa<MemberExpr>(Expr) ||
+      isa<ParenExpr>(FullExpr) ||
+      isa<ParenListExpr>(Expr) ||
+      isa<SizeOfPackExpr>(Expr))
+    return false;
+
+  return true;
+}
 static bool castOperatorNeedsParens(const Expr *FullExpr) {
   const Expr* Expr = FullExpr->IgnoreImpCasts();
   if (isa<ArraySubscriptExpr>(Expr) ||
diff --git a/test/ARCMT/objcmt-subscripting-literals.m b/test/ARCMT/objcmt-subscripting-literals.m
index 147595182d..0371e2e2ca 100644
--- a/test/ARCMT/objcmt-subscripting-literals.m
+++ b/test/ARCMT/objcmt-subscripting-literals.m
@@ -136,6 +136,8 @@ typedef const struct __CFString * CFStringRef;
   [mdict setObject:[dict objectForKey:@"key1"] forKey:[dict objectForKey:[NSArray arrayWithObject:@"arrkey"]]];
   __strong NSArray **parr = 0;
   o = [*parr objectAtIndex:2];
+  void *hd;
+  o = [(NSArray*)hd objectAtIndex:2];
 }
 @end
 
diff --git a/test/ARCMT/objcmt-subscripting-literals.m.result b/test/ARCMT/objcmt-subscripting-literals.m.result
index 5c8a4ecc40..333d0b4c38 100644
--- a/test/ARCMT/objcmt-subscripting-literals.m.result
+++ b/test/ARCMT/objcmt-subscripting-literals.m.result
@@ -136,6 +136,8 @@ typedef const struct __CFString * CFStringRef;
   mdict[dict[@[@"arrkey"]]] = dict[@"key1"];
   __strong NSArray **parr = 0;
   o = (*parr)[2];
+  void *hd;
+  o = ((NSArray*)hd)[2];
 }
 @end