Make sure parens/braces/brackets are correctly balanced.

In a line like:

(;

the semicolon leaves Parser:ParenCount unbalanced (it's 1 even though we stopped looking for a right paren).
This may affect later parsing and result in bad recovery for parsing errors.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@106213 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 1 deletions

diff --git a/lib/Parse/Parser.cpp b/lib/Parse/Parser.cpp
index 225a793af5..7d999ac408 100644
--- a/lib/Parse/Parser.cpp
+++ b/lib/Parse/Parser.cpp
@@ -127,7 +127,16 @@ SourceLocation Parser::MatchRHSPunctuation(tok::TokenKind RHSTok,
   }
   Diag(Tok, DID);
   Diag(LHSLoc, diag::note_matching) << LHSName;
-  SkipUntil(RHSTok);
+  if (!SkipUntil(RHSTok)) {
+    // We stopped before finding a RHS token, e.g. we encountered a ';'.
+    // Balance Paren/Brace/Bracket counting. 
+    switch (RHSTok) {
+    default: break;
+    case tok::r_paren : assert(ParenCount > 0); --ParenCount; break;
+    case tok::r_brace : assert(BraceCount > 0); --BraceCount; break;
+    case tok::r_square: assert(BracketCount > 0); --BracketCount; break;
+    }
+  }
   return R;
 }
 
@@ -401,6 +410,8 @@ void Parser::ParseTranslationUnit() {
 ///
 /// [C++0x/GNU] 'extern' 'template' declaration
 Parser::DeclGroupPtrTy Parser::ParseExternalDeclaration(CXX0XAttributeList Attr) {
+  ParenBraceBracketBalancer BalancerRAIIObj(*this);
+  
   DeclPtrTy SingleDecl;
   switch (Tok.getKind()) {
   case tok::semi: