support builtin features with Ruby and C.

Support loading builtin features written in Ruby, which implement
with C builtin functions.
[Feature #16254]

Several features:

(1) Load .rb file at boottime with native binary.

Now, prelude.rb is loaded at boottime. However, this file is contained
into the interpreter as a text format and we need to compile it.
This patch contains a feature to load from binary format.

(2) __builtin_func() in Ruby call func() written in C.

In Ruby file, we can write `__builtin_func()` like method call.
However this is not a method call, but special syntax to call
a function `func()` written in C. C functions should be defined
in a file (same compile unit) which load this .rb file.

Functions (`func` in above example) should be defined with
  (a) 1st parameter: rb_execution_context_t *ec
  (b) rest parameters (0 to 15).
  (c) VALUE return type.
This is very similar requirements for functions used by
rb_define_method(), however `rb_execution_context_t *ec`
is new requirement.

(3) automatic C code generation from .rb files.

tool/mk_builtin_loader.rb creates a C code to load .rb files
needed by miniruby and ruby command. This script is run by
BASERUBY, so *.rb should be written in BASERUBY compatbile
syntax. This script load a .rb file and find all of __builtin_
prefix method calls, and generate a part of C code to export
functions.

tool/mk_builtin_binary.rb creates a C code which contains
binary compiled Ruby files needed by ruby command.

1 files changed, 2 insertions, 0 deletions

diff --git a/vm.c b/vm.c
index ed02a71a48..29745143b7 100644
--- a/vm.c
+++ b/vm.c
@@ -19,6 +19,8 @@
 #include "vm_debug.h"
 #include "iseq.h"
 #include "eval_intern.h"
+#include "builtin.h"
+
 #ifndef MJIT_HEADER
 #include "probes.h"
 #else