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, 48 insertions, 0 deletions

diff --git a/insns.def b/insns.def
index b59ae6a760..993bc047ee 100644
--- a/insns.def
+++ b/insns.def
@@ -1488,6 +1488,54 @@ opt_call_c_function
     NEXT_INSN();
 }
 
+/* call specific function with args */
+DEFINE_INSN
+invokebuiltin
+(RB_BUILTIN bf)
+(...)
+(VALUE ret)
+// attr bool leaf = false; /* anything can happen inside */
+// attr rb_snum_t sp_inc = 1 - bf->argc;
+{
+    ret = vm_invoke_builtin(ec, reg_cfp, bf);
+}
+
+/* call specific function with args (same parameters) */
+DEFINE_INSN
+opt_invokebuiltin_delegate
+(RB_BUILTIN bf)
+()
+(VALUE ret)
+// attr bool leaf = false; /* anything can happen inside */
+{
+    ret = vm_invoke_builtin_delegate(ec, reg_cfp, bf);
+}
+
+/* call specific function with args (same parameters) and leave */
+DEFINE_INSN
+opt_invokebuiltin_delegate_leave
+(RB_BUILTIN bf)
+()
+(VALUE val)
+// attr bool leaf = false; /* anything can happen inside */
+{
+    val = vm_invoke_builtin_delegate(ec, reg_cfp, bf);
+
+    /* leave fastpath */
+    /* TracePoint/return should fallback this insn to invokecfuncwparam */
+    if (vm_pop_frame(ec, GET_CFP(), GET_EP())) {
+#if OPT_CALL_THREADED_CODE
+        rb_ec_thread_ptr(ec)->retval = val;
+        return 0;
+#else
+        return val;
+#endif
+    }
+    else {
+        RESTORE_REGS();
+    }
+}
+
 /* BLT */
 DEFINE_INSN_IF(SUPPORT_JOKE)
 bitblt