RubyVM::InstructionSequence

The InstructionSequence class represents a compiled sequence of instructions for the Ruby Virtual Machine.

With it, you can get a handle to the instructions that make up a method or a proc, compile strings of Ruby code down to VM instructions, and disassemble instruction sequences to strings for easy inspection. It is mostly useful if you want to learn how the Ruby VM works, but it also lets you control various settings for the Ruby iseq compiler.

You can find the source for the VM instructions in insns.def in the Ruby source.

The instruction sequence results will almost certainly change as Ruby changes, so example output in this documentation may be different from what you see.

Public Class Methods

compile(source[, file[, path[, line[, options]]]]) → iseq click to toggle source

Takes source, a String of Ruby code and compiles it to an InstructionSequence.

Optionally takes file, path, and line which describe the filename, absolute path and first line number of the ruby code in source which are metadata attached to the returned iseq.

options, which can be true, false or a Hash, is used to modify the default behavior of the Ruby iseq compiler.

For details regarding valid compile options see ::compile_option=.

RubyVM::InstructionSequence.compile("a = 1 + 2")
#=> <RubyVM::InstructionSequence:<compiled>@<compiled>>

 
               static VALUE
iseq_s_compile(int argc, VALUE *argv, VALUE self)
{
    VALUE src, file = Qnil, path = Qnil, line = INT2FIX(1), opt = Qnil;

    rb_secure(1);

    rb_scan_args(argc, argv, "14", &src, &file, &path, &line, &opt);
    if (NIL_P(file)) file = rb_str_new2("<compiled>");
    if (NIL_P(line)) line = INT2FIX(1);

    return rb_iseq_compile_with_option(src, file, path, line, 0, opt);
}

compile_file(file[, options]) → iseq click to toggle source

Takes file, a String with the location of a Ruby source file, reads, parses and compiles the file, and returns iseq, the compiled InstructionSequence with source location metadata set.

Optionally takes options, which can be true, false or a Hash, to modify the default behavior of the Ruby iseq compiler.

For details regarding valid compile options see ::compile_option=.

# /tmp/hello.rb
puts "Hello, world!"

# elsewhere
RubyVM::InstructionSequence.compile_file("/tmp/hello.rb")
#=> <RubyVM::InstructionSequence:<main>@/tmp/hello.rb>

 
               static VALUE
iseq_s_compile_file(int argc, VALUE *argv, VALUE self)
{
    VALUE file, line = INT2FIX(1), opt = Qnil;
    VALUE parser;
    VALUE f;
    NODE *node;
    const char *fname;
    rb_compile_option_t option;

    rb_secure(1);
    rb_scan_args(argc, argv, "11", &file, &opt);
    FilePathValue(file);
    fname = StringValueCStr(file);

    f = rb_file_open_str(file, "r");

    parser = rb_parser_new();
    node = rb_parser_compile_file(parser, fname, f, NUM2INT(line));
    make_compile_option(&option, opt);
    return rb_iseq_new_with_opt(node, rb_str_new2("<main>"), file,
                                rb_realpath_internal(Qnil, file, 1), line, Qfalse,
                                ISEQ_TYPE_TOP, &option);
}

compile_option → options click to toggle source

Returns a hash of default options used by the Ruby iseq compiler.

For details, see ::compile_option=.

 
               static VALUE
iseq_s_compile_option_get(VALUE self)
{
    return make_compile_option_value(&COMPILE_OPTION_DEFAULT);
}

compile_option = options click to toggle source

Sets the default values for various optimizations in the Ruby iseq compiler.

Possible values for options include true, which enables all options, false which disables all options, and nil which leaves all options unchanged.

You can also pass a Hash of options that you want to change, any options not present in the hash will be left unchanged.

Possible option names (which are keys in options) which can be set to true or false include:

:inline_const_cache
:instructions_unification
:operands_unification
:peephole_optimization
:specialized_instruction
:stack_caching
:tailcall_optimization
:trace_instruction

Additionally, :debug_level can be set to an integer.

These default options can be overwritten for a single run of the iseq compiler by passing any of the above values as the options parameter to ::new, ::compile and ::compile_file.

 
               static VALUE
iseq_s_compile_option_set(VALUE self, VALUE opt)
{
    rb_compile_option_t option;
    rb_secure(1);
    make_compile_option(&option, opt);
    COMPILE_OPTION_DEFAULT = option;
    return opt;
}

disasm(body) → str click to toggle source

disassemble(body) → str

Takes body, a Method or Proc object, and returns a String with the human readable instructions for body.

For a Method object:

# /tmp/method.rb
def hello
  puts "hello, world"
end

puts RubyVM::InstructionSequence.disasm(method(:hello))

Produces:

== disasm: <RubyVM::InstructionSequence:hello@/tmp/method.rb>============
0000 trace            8                                               (   1)
0002 trace            1                                               (   2)
0004 putself
0005 putstring        "hello, world"
0007 send             :puts, 1, nil, 8, <ic:0>
0013 trace            16                                              (   3)
0015 leave                                                            (   2)

For a Proc:

# /tmp/proc.rb
p = proc { num = 1 + 2 }
puts RubyVM::InstructionSequence.disasm(p)

Produces:

== disasm: <RubyVM::InstructionSequence:block in <main>@/tmp/proc.rb>===
== catch table
| catch type: redo   st: 0000 ed: 0012 sp: 0000 cont: 0000
| catch type: next   st: 0000 ed: 0012 sp: 0000 cont: 0012
|------------------------------------------------------------------------
local table (size: 2, argc: 0 [opts: 0, rest: -1, post: 0, block: -1] s1)
[ 2] num
0000 trace            1                                               (   1)
0002 putobject        1
0004 putobject        2
0006 opt_plus         <ic:1>
0008 dup
0009 setlocal         num, 0
0012 leave

 
               static VALUE
iseq_s_disasm(VALUE klass, VALUE body)
{
    VALUE iseqval = iseq_s_of(klass, body);
    return NIL_P(iseqval) ? Qnil : rb_iseq_disasm(iseqval);
}

disasm(body) → str click to toggle source

disassemble(body) → str

Takes body, a Method or Proc object, and returns a String with the human readable instructions for body.

For a Method object:

# /tmp/method.rb
def hello
  puts "hello, world"
end

puts RubyVM::InstructionSequence.disasm(method(:hello))

Produces:

== disasm: <RubyVM::InstructionSequence:hello@/tmp/method.rb>============
0000 trace            8                                               (   1)
0002 trace            1                                               (   2)
0004 putself
0005 putstring        "hello, world"
0007 send             :puts, 1, nil, 8, <ic:0>
0013 trace            16                                              (   3)
0015 leave                                                            (   2)

For a Proc:

# /tmp/proc.rb
p = proc { num = 1 + 2 }
puts RubyVM::InstructionSequence.disasm(p)

Produces:

== disasm: <RubyVM::InstructionSequence:block in <main>@/tmp/proc.rb>===
== catch table
| catch type: redo   st: 0000 ed: 0012 sp: 0000 cont: 0000
| catch type: next   st: 0000 ed: 0012 sp: 0000 cont: 0012
|------------------------------------------------------------------------
local table (size: 2, argc: 0 [opts: 0, rest: -1, post: 0, block: -1] s1)
[ 2] num
0000 trace            1                                               (   1)
0002 putobject        1
0004 putobject        2
0006 opt_plus         <ic:1>
0008 dup
0009 setlocal         num, 0
0012 leave

 
               static VALUE
iseq_s_disasm(VALUE klass, VALUE body)
{
    VALUE iseqval = iseq_s_of(klass, body);
    return NIL_P(iseqval) ? Qnil : rb_iseq_disasm(iseqval);
}

new(source[, file[, path[, line[, options]]]]) → iseq click to toggle source

Takes source, a String of Ruby code and compiles it to an InstructionSequence.

Optionally takes file, path, and line which describe the filename, absolute path and first line number of the ruby code in source which are metadata attached to the returned iseq.

options, which can be true, false or a Hash, is used to modify the default behavior of the Ruby iseq compiler.

For details regarding valid compile options see ::compile_option=.

RubyVM::InstructionSequence.compile("a = 1 + 2")
#=> <RubyVM::InstructionSequence:<compiled>@<compiled>>

 
               static VALUE
iseq_s_compile(int argc, VALUE *argv, VALUE self)
{
    VALUE src, file = Qnil, path = Qnil, line = INT2FIX(1), opt = Qnil;

    rb_secure(1);

    rb_scan_args(argc, argv, "14", &src, &file, &path, &line, &opt);
    if (NIL_P(file)) file = rb_str_new2("<compiled>");
    if (NIL_P(line)) line = INT2FIX(1);

    return rb_iseq_compile_with_option(src, file, path, line, 0, opt);
}

of(p1) click to toggle source

Returns the instruction sequence containing the given proc or method.

For example, using irb:

# a proc
> p = proc { num = 1 + 2 }
> RubyVM::InstructionSequence.of(p)
> #=> <RubyVM::InstructionSequence:block in irb_binding@(irb)>

# for a method
> def foo(bar); puts bar; end
> RubyVM::InstructionSequence.of(method(:foo))
> #=> <RubyVM::InstructionSequence:foo@(irb)>

Using ::compile_file:

# /tmp/iseq_of.rb
def hello
  puts "hello, world"
end

$a_global_proc = proc { str = 'a' + 'b' }

# in irb
> require '/tmp/iseq_of.rb'

# first the method hello
> RubyVM::InstructionSequence.of(method(:hello))
> #=> #<RubyVM::InstructionSequence:0x007fb73d7cb1d0>

# then the global proc
> RubyVM::InstructionSequence.of($a_global_proc)
> #=> #<RubyVM::InstructionSequence:0x007fb73d7caf78>

 
               static VALUE
iseq_s_of(VALUE klass, VALUE body)
{
    VALUE ret = Qnil;
    rb_iseq_t *iseq;

    rb_secure(1);

    if (rb_obj_is_proc(body)) {
        rb_proc_t *proc;
        GetProcPtr(body, proc);
        iseq = proc->block.iseq;
        if (RUBY_VM_NORMAL_ISEQ_P(iseq)) {
            ret = iseq->self;
        }
    }
    else if ((iseq = rb_method_get_iseq(body)) != 0) {
        ret = iseq->self;
    }
    return ret;
}

Public Instance Methods

absolute_path() click to toggle source

Returns the absolute path of this instruction sequence.

nil if the iseq was evaluated from a string.

For example, using ::compile_file:

# /tmp/method.rb
def hello
  puts "hello, world"
end

# in irb
> iseq = RubyVM::InstructionSequence.compile_file('/tmp/method.rb')
> iseq.absolute_path #=> /tmp/method.rb

 
               static VALUE
iseq_absolute_path(VALUE self)
{
    rb_iseq_t *iseq;
    GetISeqPtr(self, iseq);
    return iseq->location.absolute_path;
}

base_label() click to toggle source

Returns the base label of this instruction sequence.

For example, using irb:

iseq = RubyVM::InstructionSequence.compile('num = 1 + 2')
#=> <RubyVM::InstructionSequence:<compiled>@<compiled>>
iseq.base_label
#=> "<compiled>"

Using ::compile_file:

# /tmp/method.rb
def hello
  puts "hello, world"
end

# in irb
> iseq = RubyVM::InstructionSequence.compile_file('/tmp/method.rb')
> iseq.base_label #=> <main>

 
               static VALUE
iseq_base_label(VALUE self)
{
    rb_iseq_t *iseq;
    GetISeqPtr(self, iseq);
    return iseq->location.base_label;
}

disasm → str click to toggle source

Returns the instruction sequence as a String in human readable form.

puts RubyVM::InstructionSequence.compile('1 + 2').disasm

Produces:

== disasm: <RubyVM::InstructionSequence:<compiled>@<compiled>>==========
0000 trace            1                                               (   1)
0002 putobject        1
0004 putobject        2
0006 opt_plus         <ic:1>
0008 leave

 
               VALUE
rb_iseq_disasm(VALUE self)
{
    rb_iseq_t *iseqdat = iseq_check(self);
    VALUE *iseq;
    VALUE str = rb_str_new(0, 0);
    VALUE child = rb_ary_new();
    unsigned long size;
    int i;
    long l;
    ID *tbl;
    size_t n;
    enum {header_minlen = 72};

    rb_secure(1);

    iseq = iseqdat->iseq;
    size = iseqdat->iseq_size;

    rb_str_cat2(str, "== disasm: ");

    rb_str_concat(str, iseq_inspect(iseqdat->self));
    if ((l = RSTRING_LEN(str)) < header_minlen) {
        rb_str_resize(str, header_minlen);
        memset(RSTRING_PTR(str) + l, '=', header_minlen - l);
    }
    rb_str_cat2(str, "\n");

    /* show catch table information */
    if (iseqdat->catch_table_size != 0) {
        rb_str_cat2(str, "== catch table\n");
    }
    for (i = 0; i < iseqdat->catch_table_size; i++) {
        struct iseq_catch_table_entry *entry = &iseqdat->catch_table[i];
        rb_str_catf(str,
                    "| catch type: %-6s st: %04d ed: %04d sp: %04d cont: %04d\n",
                    catch_type((int)entry->type), (int)entry->start,
                    (int)entry->end, (int)entry->sp, (int)entry->cont);
        if (entry->iseq) {
            rb_str_concat(str, rb_iseq_disasm(entry->iseq));
        }
    }
    if (iseqdat->catch_table_size != 0) {
        rb_str_cat2(str, "|-------------------------------------"
                    "-----------------------------------\n");
    }

    /* show local table information */
    tbl = iseqdat->local_table;

    if (tbl) {
        rb_str_catf(str,
                    "local table (size: %d, argc: %d "
                    "[opts: %d, rest: %d, post: %d, block: %d] s%d)\n",
                    iseqdat->local_size, iseqdat->argc,
                    iseqdat->arg_opts, iseqdat->arg_rest,
                    iseqdat->arg_post_len, iseqdat->arg_block,
                    iseqdat->arg_simple);

        for (i = 0; i < iseqdat->local_table_size; i++) {
            long width;
            VALUE name = id_to_name(tbl[i], 0);
            char argi[0x100] = "";
            char opti[0x100] = "";

            if (iseqdat->arg_opts) {
                int argc = iseqdat->argc;
                int opts = iseqdat->arg_opts;
                if (i >= argc && i < argc + opts - 1) {
                    snprintf(opti, sizeof(opti), "Opt=%"PRIdVALUE,
                             iseqdat->arg_opt_table[i - argc]);
                }
            }

            snprintf(argi, sizeof(argi), "%s%s%s%s%s", /* arg, opts, rest, post  block */
                     iseqdat->argc > i ? "Arg" : "",
                     opti,
                     iseqdat->arg_rest == i ? "Rest" : "",
                     (iseqdat->arg_post_start <= i &&
                      i < iseqdat->arg_post_start + iseqdat->arg_post_len) ? "Post" : "",
                     iseqdat->arg_block == i ? "Block" : "");

            rb_str_catf(str, "[%2d] ", iseqdat->local_size - i);
            width = RSTRING_LEN(str) + 11;
            if (name)
                rb_str_append(str, name);
            else
                rb_str_cat2(str, "?");
            if (*argi) rb_str_catf(str, "<%s>", argi);
            if ((width -= RSTRING_LEN(str)) > 0) rb_str_catf(str, "%*s", (int)width, "");
        }
        rb_str_cat2(str, "\n");
    }

    /* show each line */
    for (n = 0; n < size;) {
        n += rb_iseq_disasm_insn(str, iseq, n, iseqdat, child);
    }

    for (i = 0; i < RARRAY_LEN(child); i++) {
        VALUE isv = rb_ary_entry(child, i);
        rb_str_concat(str, rb_iseq_disasm(isv));
    }

    return str;
}

disassemble → str click to toggle source

Returns the instruction sequence as a String in human readable form.

puts RubyVM::InstructionSequence.compile('1 + 2').disasm

Produces:

== disasm: <RubyVM::InstructionSequence:<compiled>@<compiled>>==========
0000 trace            1                                               (   1)
0002 putobject        1
0004 putobject        2
0006 opt_plus         <ic:1>
0008 leave

 
               VALUE
rb_iseq_disasm(VALUE self)
{
    rb_iseq_t *iseqdat = iseq_check(self);
    VALUE *iseq;
    VALUE str = rb_str_new(0, 0);
    VALUE child = rb_ary_new();
    unsigned long size;
    int i;
    long l;
    ID *tbl;
    size_t n;
    enum {header_minlen = 72};

    rb_secure(1);

    iseq = iseqdat->iseq;
    size = iseqdat->iseq_size;

    rb_str_cat2(str, "== disasm: ");

    rb_str_concat(str, iseq_inspect(iseqdat->self));
    if ((l = RSTRING_LEN(str)) < header_minlen) {
        rb_str_resize(str, header_minlen);
        memset(RSTRING_PTR(str) + l, '=', header_minlen - l);
    }
    rb_str_cat2(str, "\n");

    /* show catch table information */
    if (iseqdat->catch_table_size != 0) {
        rb_str_cat2(str, "== catch table\n");
    }
    for (i = 0; i < iseqdat->catch_table_size; i++) {
        struct iseq_catch_table_entry *entry = &iseqdat->catch_table[i];
        rb_str_catf(str,
                    "| catch type: %-6s st: %04d ed: %04d sp: %04d cont: %04d\n",
                    catch_type((int)entry->type), (int)entry->start,
                    (int)entry->end, (int)entry->sp, (int)entry->cont);
        if (entry->iseq) {
            rb_str_concat(str, rb_iseq_disasm(entry->iseq));
        }
    }
    if (iseqdat->catch_table_size != 0) {
        rb_str_cat2(str, "|-------------------------------------"
                    "-----------------------------------\n");
    }

    /* show local table information */
    tbl = iseqdat->local_table;

    if (tbl) {
        rb_str_catf(str,
                    "local table (size: %d, argc: %d "
                    "[opts: %d, rest: %d, post: %d, block: %d] s%d)\n",
                    iseqdat->local_size, iseqdat->argc,
                    iseqdat->arg_opts, iseqdat->arg_rest,
                    iseqdat->arg_post_len, iseqdat->arg_block,
                    iseqdat->arg_simple);

        for (i = 0; i < iseqdat->local_table_size; i++) {
            long width;
            VALUE name = id_to_name(tbl[i], 0);
            char argi[0x100] = "";
            char opti[0x100] = "";

            if (iseqdat->arg_opts) {
                int argc = iseqdat->argc;
                int opts = iseqdat->arg_opts;
                if (i >= argc && i < argc + opts - 1) {
                    snprintf(opti, sizeof(opti), "Opt=%"PRIdVALUE,
                             iseqdat->arg_opt_table[i - argc]);
                }
            }

            snprintf(argi, sizeof(argi), "%s%s%s%s%s", /* arg, opts, rest, post  block */
                     iseqdat->argc > i ? "Arg" : "",
                     opti,
                     iseqdat->arg_rest == i ? "Rest" : "",
                     (iseqdat->arg_post_start <= i &&
                      i < iseqdat->arg_post_start + iseqdat->arg_post_len) ? "Post" : "",
                     iseqdat->arg_block == i ? "Block" : "");

            rb_str_catf(str, "[%2d] ", iseqdat->local_size - i);
            width = RSTRING_LEN(str) + 11;
            if (name)
                rb_str_append(str, name);
            else
                rb_str_cat2(str, "?");
            if (*argi) rb_str_catf(str, "<%s>", argi);
            if ((width -= RSTRING_LEN(str)) > 0) rb_str_catf(str, "%*s", (int)width, "");
        }
        rb_str_cat2(str, "\n");
    }

    /* show each line */
    for (n = 0; n < size;) {
        n += rb_iseq_disasm_insn(str, iseq, n, iseqdat, child);
    }

    for (i = 0; i < RARRAY_LEN(child); i++) {
        VALUE isv = rb_ary_entry(child, i);
        rb_str_concat(str, rb_iseq_disasm(isv));
    }

    return str;
}

eval → obj click to toggle source

Evaluates the instruction sequence and returns the result.

RubyVM::InstructionSequence.compile("1 + 2").eval #=> 3

 
               static VALUE
iseq_eval(VALUE self)
{
    rb_secure(1);
    return rb_iseq_eval(self);
}

first_lineno() click to toggle source

Returns the number of the first source line where the instruction sequence was loaded from.

For example, using irb:

iseq = RubyVM::InstructionSequence.compile('num = 1 + 2')
#=> <RubyVM::InstructionSequence:<compiled>@<compiled>>
iseq.first_lineno
#=> 1

 
               static VALUE
iseq_first_lineno(VALUE self)
{
    rb_iseq_t *iseq;
    GetISeqPtr(self, iseq);
    return iseq->location.first_lineno;
}

inspect() click to toggle source

Returns a human-readable string representation of this instruction sequence, including the label and path.

 
               static VALUE
iseq_inspect(VALUE self)
{
    rb_iseq_t *iseq;
    GetISeqPtr(self, iseq);
    if (!iseq->location.label) {
        return rb_sprintf("#<%s: uninitialized>", rb_obj_classname(self));
    }

    return rb_sprintf("<%s:%s@%s>",
                      rb_obj_classname(self),
                      RSTRING_PTR(iseq->location.label), RSTRING_PTR(iseq->location.path));
}

label() click to toggle source

Returns the label of this instruction sequence.

<main> if it's at the top level, <compiled> if it was evaluated from a string.

For example, using irb:

iseq = RubyVM::InstructionSequence.compile('num = 1 + 2')
#=> <RubyVM::InstructionSequence:<compiled>@<compiled>>
iseq.label
#=> "<compiled>"

Using ::compile_file:

# /tmp/method.rb
def hello
  puts "hello, world"
end

# in irb
> iseq = RubyVM::InstructionSequence.compile_file('/tmp/method.rb')
> iseq.label #=> <main>

 
               static VALUE
iseq_label(VALUE self)
{
    rb_iseq_t *iseq;
    GetISeqPtr(self, iseq);
    return iseq->location.label;
}

line_trace_all() click to toggle source

Experimental MRI specific feature, only available as C level api.

Returns all specified_line events.

 
               VALUE
rb_iseq_line_trace_all(VALUE iseqval)
{
    VALUE result = rb_ary_new();
    rb_iseq_line_trace_each(iseqval, collect_trace, (void *)result);
    return result;
}

line_trace_specify(p1, p2) click to toggle source

Experimental MRI specific feature, only available as C level api.

Set a specified_line event at the given line position, if the set parameter is true.

This method is useful for building a debugger breakpoint at a specific line.

A TypeError is raised if set is not boolean.

If pos is a negative integer a TypeError exception is raised.

 
               VALUE
rb_iseq_line_trace_specify(VALUE iseqval, VALUE pos, VALUE set)
{
    struct set_specifc_data data;

    data.prev = 0;
    data.pos = NUM2INT(pos);
    if (data.pos < 0) rb_raise(rb_eTypeError, "`pos' is negative");

    switch (set) {
      case Qtrue:  data.set = 1; break;
      case Qfalse: data.set = 0; break;
      default:
        rb_raise(rb_eTypeError, "`set' should be true/false");
    }

    rb_iseq_line_trace_each(iseqval, line_trace_specify, (void *)&data);

    if (data.prev == 0) {
        rb_raise(rb_eTypeError, "`pos' is out of range.");
    }
    return data.prev == 1 ? Qtrue : Qfalse;
}

path() click to toggle source

Returns the path of this instruction sequence.

<compiled> if the iseq was evaluated from a string.

For example, using irb:

iseq = RubyVM::InstructionSequence.compile('num = 1 + 2')
#=> <RubyVM::InstructionSequence:<compiled>@<compiled>>
iseq.path
#=> "<compiled>"

Using ::compile_file:

# /tmp/method.rb
def hello
  puts "hello, world"
end

# in irb
> iseq = RubyVM::InstructionSequence.compile_file('/tmp/method.rb')
> iseq.path #=> /tmp/method.rb

 
               static VALUE
iseq_path(VALUE self)
{
    rb_iseq_t *iseq;
    GetISeqPtr(self, iseq);
    return iseq->location.path;
}

to_a → ary click to toggle source

Returns an Array with 14 elements representing the instruction sequence with the following data:

magic

A string identifying the data format. Always YARVInstructionSequence/SimpleDataFormat.

major_version

The major version of the instruction sequence.

minor_version

The minor version of the instruction sequence.

format_type

A number identifying the data format. Always 1.

misc

A hash containing:

:arg_size: the total number of arguments taken by the method or the block (0 if iseq doesn't represent a method or block)
:local_size: the number of local variables + 1
:stack_max: used in calculating the stack depth at which a SystemStackError is thrown.

label

The name of the context (block, method, class, module, etc.) that this instruction sequence belongs to.

<main> if it's at the top level, <compiled> if it was evaluated from a string.

path

The relative path to the Ruby file where the instruction sequence was loaded from.

<compiled> if the iseq was evaluated from a string.

absolute_path

The absolute path to the Ruby file where the instruction sequence was loaded from.

nil if the iseq was evaluated from a string.

first_lineno

The number of the first source line where the instruction sequence was loaded from.

type

The type of the instruction sequence.

Valid values are :top, :method, :block, :class, :rescue, :ensure, :eval, :main, and :defined_guard.

locals

An array containing the names of all arguments and local variables as symbols.

args

The arity if the method or block only has required arguments.

Otherwise an array of:

[required_argc, [optional_arg_labels, ...],
 splat_index, post_splat_argc, post_splat_index,
 block_index, simple]

More info about these values can be found in vm_core.h.

catch_table

A list of exceptions and control flow operators (rescue, next, redo, break, etc.).

bytecode

An array of arrays containing the instruction names and operands that make up the body of the instruction sequence.

 
               static VALUE
iseq_to_a(VALUE self)
{
    rb_iseq_t *iseq = iseq_check(self);
    rb_secure(1);
    return iseq_data_to_ary(iseq);
}

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