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, 0 insertions, 3 deletions

diff --git a/src/load.c b/src/load.c
index 55e0845f3..ab0346750 100644
--- a/src/load.c
+++ b/src/load.c
@@ -317,7 +317,6 @@ read_debug_record(mrb_state *mrb, const uint8_t *start, mrb_irep* irep, size_t *
   for (f_idx = 0; f_idx < irep->debug_info->flen; ++f_idx) {
     mrb_irep_debug_info_file *file;
     uint16_t filename_idx;
-    mrb_int len;
 
     file = (mrb_irep_debug_info_file *)mrb_malloc(mrb, sizeof(*file));
     irep->debug_info->files[f_idx] = file;
@@ -330,8 +329,6 @@ read_debug_record(mrb_state *mrb, const uint8_t *start, mrb_irep* irep, size_t *
     bin += sizeof(uint16_t);
     mrb_assert(filename_idx < filenames_len);
     file->filename_sym = filenames[filename_idx];
-    len = 0;
-    file->filename = mrb_sym2name_len(mrb, file->filename_sym, &len);
 
     file->line_entry_count = bin_to_uint32(bin);
     bin += sizeof(uint32_t);