Fix access-after-free with statement expressions

The return value of statement expressions might refer to local
symbols, so those can't be popped.  The old error message always
was just a band-aid, and since disabling it for pointer types it
wasn't effective anyway.  It also never considered that also the
vtop->sym member might have referred to such symbols (see the
testcase with the local static, that used to segfault).

For fixing this (can be seen better with valgrind and SYM_DEBUG)
simply leave local symbols of stmt exprs on the stack.

1 files changed, 1 insertions, 1 deletions

diff --git a/tcc.h b/tcc.h
index f990f8f..e4b5a0e 100644
--- a/tcc.h
+++ b/tcc.h
@@ -1099,7 +1099,7 @@ ST_INLN void sym_free(Sym *sym);
 ST_FUNC Sym *sym_push2(Sym **ps, int v, int t, long c);
 ST_FUNC Sym *sym_find2(Sym *s, int v);
 ST_FUNC Sym *sym_push(int v, CType *type, int r, int c);
-ST_FUNC void sym_pop(Sym **ptop, Sym *b);
+ST_FUNC void sym_pop(Sym **ptop, Sym *b, int keep);
 ST_INLN Sym *struct_find(int v);
 ST_INLN Sym *sym_find(int v);
 ST_FUNC Sym *global_identifier_push(int v, int t, int c);