Fix the following example:
Object.const_set :A, Module.new{const_set :B, Class.new}
ab = A::B.to_s
p ab #=> "A::B" # Good
ab[0] = "x"
p A::B.to_s #=> "x::B" # Bad
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.
For short symbols with alpha numeric characters, `mrb_sym2name_len()`
returns the same buffer `mrb->symbuf`. Some occasion, we forget the fact
that the second call could overwrite the result of first call of the
function.
We have prepared the static function `sym2name()` which specifies the
buffer region for inline packed symbols and use the function in
`mrb_sym_to_s`.
Functions to add prototypes to headers:
* mrb_ary_splice()
* mrb_notimplement()
* mrb_vformat()
* mrb_cstr_to_dbl()
* mrb_cstr_to_inum()
Functions to be made `static` (`MRB_API` was not needed):
* mrb_mod_module_function()
* mrb_obj_hash()
* mrb_str_len_to_inum()
Functions to remove `MRB_API` from definitions (referenced from within `libmruby`):
* mrb_mod_cv_defined()
* mrb_mod_cv_get()
* mrb_f_send()
- Move calling `mrb_debug_get_filename()` to after `lineno` check.
- Remove unneeded array check in `print_backtrace()`.
- Add a few `const` qualifier.
Small symbols with all alphanumeric characters (<5) are packed in 32bit
symbol integer a la base64. This means those small symbols are not
listed in `Symbol.all_symbols`.
In 4174e02, we removed the symbol hash table from `mrb_state` but
`find_symbol` was too slow with linear search. My performance estimation
was wrong. So we implemented a new compact hash table for symbols.
Use linear search instead. Number of symbols is usually small (<1K), so
we don't need performance boost from hash tables. In our benchmark
measurement, hash tables consumes 790KB for `build/full-debug/mrbtest`.
Yukihiro "Matz" Matsumoto