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, 9 insertions, 0 deletions

diff --git a/vm_core.h b/vm_core.h
index fabe8bbc10..9e158df923 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -564,6 +564,10 @@ typedef struct rb_hook_list_struct {
     unsigned int running;
 } rb_hook_list_t;
 
+
+// see builtin.h for definition
+typedef const struct rb_builtin_function *RB_BUILTIN;
+
 typedef struct rb_vm_struct {
     VALUE self;
 
@@ -647,6 +651,8 @@ typedef struct rb_vm_struct {
     VALUE *defined_strings;
     st_table *frozen_strings;
 
+    const struct rb_builtin_function *builtin_function_table;
+
     /* params */
     struct { /* size in byte */
 	size_t thread_vm_stack_size;
@@ -880,6 +886,9 @@ typedef struct rb_execution_context_struct {
     } machine;
 } rb_execution_context_t;
 
+// for builtin.h
+#define VM_CORE_H_EC_DEFINED 1
+
 // Set the vm_stack pointer in the execution context.
 void rb_ec_set_vm_stack(rb_execution_context_t *ec, VALUE *stack, size_t size);