class RubyVM

The RubyVM module only exists on MRI. RubyVM is not defined in other Ruby implementations such as JRuby and TruffleRuby.

The RubyVM module provides some access to MRI internals. This module is for very limited purposes, such as debugging, prototyping, and research. Normal users must not use it. This module is not portable between Ruby implementations.

Constants

DEFAULT_PARAMS

DEFAULT_PARAMS This constant exposes the VM's default parameters. Note that changing these values does not affect VM execution. Specification is not stable and you should not depend on this value. Of course, this constant is MRI specific.

INSTRUCTION_NAMES

INSTRUCTION_NAMES A list of bytecode instruction names in MRI. This constant is MRI specific.

OPTS

OPTS An Array of VM build options. This constant is MRI specific.

Public Class Methods

stat → Hash click to toggle source
stat(hsh) → hsh
stat(Symbol) → Numeric

Returns a Hash containing implementation-dependent counters inside the VM.

This hash includes information about method/constant cache serials:

{
  :global_method_state=>251,
  :global_constant_state=>481,
  :class_serial=>9029
}

The contents of the hash are implementation specific and may be changed in the future.

This method is only expected to work on C Ruby.

static VALUE
vm_stat(int argc, VALUE *argv, VALUE self)
{
    static VALUE sym_global_method_state, sym_global_constant_state, sym_class_serial;
    VALUE arg = Qnil;
    VALUE hash = Qnil, key = Qnil;

    if (rb_check_arity(argc, 0, 1) == 1) {
        arg = argv[0];
        if (SYMBOL_P(arg))
            key = arg;
        else if (RB_TYPE_P(arg, T_HASH))
            hash = arg;
        else
            rb_raise(rb_eTypeError, "non-hash or symbol given");
    }
    else {
        hash = rb_hash_new();
    }

    if (sym_global_method_state == 0) {
#define S(s) sym_##s = ID2SYM(rb_intern_const(#s))
        S(global_method_state);
        S(global_constant_state);
        S(class_serial);
#undef S
    }

#define SET(name, attr) \
    if (key == sym_##name) \
        return SERIALT2NUM(attr); \
    else if (hash != Qnil) \
        rb_hash_aset(hash, sym_##name, SERIALT2NUM(attr));

    SET(global_method_state, ruby_vm_global_method_state);
    SET(global_constant_state, ruby_vm_global_constant_state);
    SET(class_serial, ruby_vm_class_serial);
#undef SET

    if (!NIL_P(key)) { /* matched key should return above */
        rb_raise(rb_eArgError, "unknown key: %"PRIsVALUE, rb_sym2str(key));
    }

    return hash;
}