[cfe-commits] r99939 - in /cfe/trunk: lib/Parse/ParseCXXInlineMethods.cpp test/Parser/cxx-default-args.cpp

[Argiris Kirtzidis]

Author: akirtzidis
Date: Tue Mar 30 17:14:32 2010
New Revision: 99939

URL: http://llvm.org/viewvc/llvm-project?rev=99939&view=rev
Log:
When "delayed parsing" C++ default arguments, if there is an error, there may be tokens left in the token stream
that will interfere (they will be parsed as if they are after the class' '}') and a crash will occur because
the CachedTokens that holds them will be deleted while the lexer is still using them.

Make sure that the tokens of default args are removed from the token stream.
Fixes PR6647.

Added:
    cfe/trunk/test/Parser/cxx-default-args.cpp
Modified:
    cfe/trunk/lib/Parse/ParseCXXInlineMethods.cpp

Modified: cfe/trunk/lib/Parse/ParseCXXInlineMethods.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Parse/ParseCXXInlineMethods.cpp?rev=99939&r1=99938&r2=99939&view=diff
==============================================================================
--- cfe/trunk/lib/Parse/ParseCXXInlineMethods.cpp (original)
+++ cfe/trunk/lib/Parse/ParseCXXInlineMethods.cpp Tue Mar 30 17:14:32 2010
@@ -122,6 +122,9 @@
       Actions.ActOnDelayedCXXMethodParameter(CurScope, LM.DefaultArgs[I].Param);
 
       if (CachedTokens *Toks = LM.DefaultArgs[I].Toks) {
+        // Save the current token position.
+        SourceLocation origLoc = Tok.getLocation();
+
         // Parse the default argument from its saved token stream.
         Toks->push_back(Tok); // So that the current token doesn't get lost
         PP.EnterTokenStream(&Toks->front(), Toks->size(), true, false);
@@ -139,6 +142,15 @@
         else
           Actions.ActOnParamDefaultArgument(LM.DefaultArgs[I].Param, EqualLoc,
                                             move(DefArgResult));
+
+        assert(!PP.getSourceManager().isBeforeInTranslationUnit(origLoc,
+                                                           Tok.getLocation()) &&
+               "ParseAssignmentExpression went over the default arg tokens!");
+        // There could be leftover tokens (e.g. because of an error).
+        // Skip through until we reach the original token position.
+        while (Tok.getLocation() != origLoc)
+          ConsumeAnyToken();
+
         delete Toks;
         LM.DefaultArgs[I].Toks = 0;
       }

Added: cfe/trunk/test/Parser/cxx-default-args.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Parser/cxx-default-args.cpp?rev=99939&view=auto
==============================================================================
--- cfe/trunk/test/Parser/cxx-default-args.cpp (added)
+++ cfe/trunk/test/Parser/cxx-default-args.cpp Tue Mar 30 17:14:32 2010
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+// PR6647
+class C {
+  // After the error, the rest of the tokens inside the default arg should be
+  // skipped, avoiding a "expected ';' after class" after 'undecl'.
+  void m(int x = undecl + 0); // expected-error {{use of undeclared identifier 'undecl'}}
+};
+