class 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
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); }
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); }
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); }
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; }
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); }
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); }
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); }
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
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
VALUE rb_iseq_absolute_path(VALUE self) { rb_iseq_t *iseq; GetISeqPtr(self, iseq); return iseq->location.absolute_path; }
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>
VALUE rb_iseq_base_label(VALUE self) { rb_iseq_t *iseq; GetISeqPtr(self, iseq); return iseq->location.base_label; }
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, keyword: %d@%d] s%d)\n", iseqdat->local_size, iseqdat->argc, iseqdat->arg_opts, iseqdat->arg_rest, iseqdat->arg_post_len, iseqdat->arg_block, iseqdat->arg_keywords, iseqdat->local_size-iseqdat->arg_keyword, 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; }
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, keyword: %d@%d] s%d)\n", iseqdat->local_size, iseqdat->argc, iseqdat->arg_opts, iseqdat->arg_rest, iseqdat->arg_post_len, iseqdat->arg_block, iseqdat->arg_keywords, iseqdat->local_size-iseqdat->arg_keyword, 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; }
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); }
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
VALUE rb_iseq_first_lineno(VALUE self) { rb_iseq_t *iseq; GetISeqPtr(self, iseq); return iseq->location.first_lineno; }
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)); }
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>
VALUE rb_iseq_label(VALUE self) { rb_iseq_t *iseq; GetISeqPtr(self, iseq); return iseq->location.label; }
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; }
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; }
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
VALUE rb_iseq_path(VALUE self) { rb_iseq_t *iseq; GetISeqPtr(self, iseq); return iseq->location.path; }
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); }