Implements boxed expressions for Objective-C. <rdar://problem/10194391>

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@155082 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 26 insertions, 0 deletions

diff --git a/lib/Parse/ParseObjc.cpp b/lib/Parse/ParseObjc.cpp
index 789a8ae7a9..dd8259964c 100644
--- a/lib/Parse/ParseObjc.cpp
+++ b/lib/Parse/ParseObjc.cpp
@@ -2066,6 +2066,10 @@ ExprResult Parser::ParseObjCAtExpression(SourceLocation AtLoc) {
     // Objective-C dictionary literal
     return ParsePostfixExpressionSuffix(ParseObjCDictionaryLiteral(AtLoc));
           
+  case tok::l_paren:
+    // Objective-C boxed expression
+    return ParsePostfixExpressionSuffix(ParseObjCBoxedExpr(AtLoc));
+          
   default:
     if (Tok.getIdentifierInfo() == 0)
       return ExprError(Diag(AtLoc, diag::err_unexpected_at));
@@ -2580,6 +2584,28 @@ ExprResult Parser::ParseObjCNumericLiteral(SourceLocation AtLoc) {
   return Owned(Actions.BuildObjCNumericLiteral(AtLoc, Lit.take()));
 }
 
+/// ParseObjCBoxedExpr -
+/// objc-box-expression:
+///       @( assignment-expression )
+ExprResult
+Parser::ParseObjCBoxedExpr(SourceLocation AtLoc) {
+  if (Tok.isNot(tok::l_paren))
+    return ExprError(Diag(Tok, diag::err_expected_lparen_after) << "@");
+
+  BalancedDelimiterTracker T(*this, tok::l_paren);
+  T.consumeOpen();
+  ExprResult ValueExpr(ParseAssignmentExpression());
+  if (T.consumeClose())
+    return ExprError();
+  
+  // Wrap the sub-expression in a parenthesized expression, to distinguish
+  // a boxed expression from a literal.
+  SourceLocation LPLoc = T.getOpenLocation(), RPLoc = T.getCloseLocation();
+  ValueExpr = Actions.ActOnParenExpr(LPLoc, RPLoc, ValueExpr.take());
+  return Owned(Actions.BuildObjCBoxedExpr(SourceRange(AtLoc, RPLoc),
+                                          ValueExpr.take()));
+}
+
 ExprResult Parser::ParseObjCArrayLiteral(SourceLocation AtLoc) {
   ExprVector ElementExprs(Actions);                   // array elements.
   ConsumeBracket(); // consume the l_square.