Reject jumping inside stmtexprs

One can't jump into statement expressions from outside
them, like the following:

  int i = ({ label: foo(); 42; });
  goto label;

We reject this by making the labels simply not available
outside (GCC has a nicer error message about jumping into
a statement expression).

1 files changed, 7 insertions, 1 deletions

diff --git a/tccgen.c b/tccgen.c
index 53ce185..02e56eb 100644
--- a/tccgen.c
+++ b/tccgen.c
@@ -5406,7 +5406,7 @@ static void block(int *bsym, int *csym, int is_expr)
         gsym(a);
         gsym_addr(b, d);
     } else if (tok == '{') {
-        Sym *llabel;
+        Sym *llabel, *glabel;
         int block_vla_sp_loc = vla_sp_loc, saved_vlas_in_scope = vlas_in_scope;
 
         next();
@@ -5414,6 +5414,10 @@ static void block(int *bsym, int *csym, int is_expr)
         s = local_stack;
         llabel = local_label_stack;
         ++local_scope;
+	/* Labels defined inside statement expressions aren't
+	   available from the outside, so record that as well.  */
+	if (is_expr)
+	  glabel = global_label_stack;
         
         /* handle local labels declarations */
         if (tok == TOK_LABEL) {
@@ -5439,6 +5443,8 @@ static void block(int *bsym, int *csym, int is_expr)
                 block(bsym, csym, is_expr);
             }
         }
+	if (is_expr)
+	  label_pop(&global_label_stack, glabel);
         /* pop locally defined labels */
         label_pop(&local_label_stack, llabel);
         /* pop locally defined symbols */