Avoid keeping pointers from `mrb_sym2name_len()`; fix #4342

The addresses for packed inline symbols reference `mrb->symbuf` that
could be overridden by the later call of `mrb_sym2name_len`. Since
file names in call stack information are kept as symbols, keeping the
address in the C structures could cause problems like #4342.

This changes small incompatible changes in function prototypes:
* `mrb_parser_get_filename`: return value changed to `mrb_sym`.
* `mrb_debug_get_filename`: add `mrb_state*` as a first argument.
* `mrb_debug_get_line`: ditto.

I believe above functions are almost internal, and no third-party
mrbgem use them.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/backtrace.c b/src/backtrace.c
index efca2562f..e4f5a3064 100644
--- a/src/backtrace.c
+++ b/src/backtrace.c
@@ -58,10 +58,10 @@ each_backtrace(mrb_state *mrb, ptrdiff_t ciidx, mrb_code *pc0, each_backtrace_fu
       pc = pc0;
     }
 
-    loc.lineno = mrb_debug_get_line(irep, pc - irep->iseq);
+    loc.lineno = mrb_debug_get_line(mrb, irep, pc - irep->iseq);
     if (loc.lineno == -1) continue;
 
-    loc.filename = mrb_debug_get_filename(irep, pc - irep->iseq);
+    loc.filename = mrb_debug_get_filename(mrb, irep, pc - irep->iseq);
     if (!loc.filename) {
       loc.filename = "(unknown)";
     }