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, 33 insertions, 0 deletions

diff --git a/tool/mk_builtin_binary.rb b/tool/mk_builtin_binary.rb
new file mode 100644
index 0000000000..a5c962d5c1
--- /dev/null
+++ b/tool/mk_builtin_binary.rb
@@ -0,0 +1,33 @@
+#
+# make builtin_binary.inc file.
+#
+
+def dump_bin iseq
+  bin = iseq.to_binary
+  bin.each_byte.with_index{|b, index|
+    print "\n  " if (index%20) == 0
+    print "0x#{'%02x' % b.ord}, "
+  }
+end
+
+ary = []
+RubyVM::each_builtin{|feature, iseq|
+  ary << [feature, iseq]
+}
+
+$stdout = open('builtin_binary.inc', 'wb')
+
+ary.each{|feature, iseq|
+  puts "static const unsigned char #{feature}_bin[] = {"
+    dump_bin(iseq)
+  puts "};"
+}
+
+puts "static const struct builtin_binary builtin_binary[] = {"
+ary.each{|feature, iseq|
+  puts "  {#{feature.dump}, #{feature}_bin, sizeof(#{feature}_bin)},"
+}
+puts "  {NULL}," # dummy sentry
+puts "};"
+
+puts "#define BUILTIN_BINARY_SIZE #{ary.size}"