Object Shapes is used for accessing instance variables and representing the
"frozenness" of objects. Object instances have a "shape" and the shape
represents some attributes of the object (currently which instance variables are
set and the "frozenness"). Shapes form a tree data structure, and when a new
instance variable is set on an object, that object "transitions" to a new shape
in the shape tree. Each shape has an ID that is used for caching. The shape
structure is independent of class, so objects of different types can have the
same shape.
For example:
```ruby
class Foo
def initialize
# Starts with shape id 0
@a = 1 # transitions to shape id 1
@b = 1 # transitions to shape id 2
end
end
class Bar
def initialize
# Starts with shape id 0
@a = 1 # transitions to shape id 1
@b = 1 # transitions to shape id 2
end
end
foo = Foo.new # `foo` has shape id 2
bar = Bar.new # `bar` has shape id 2
```
Both `foo` and `bar` instances have the same shape because they both set
instance variables of the same name in the same order.
This technique can help to improve inline cache hits as well as generate more
efficient machine code in JIT compilers.
This commit also adds some methods for debugging shapes on objects. See
`RubyVM::Shape` for more details.
For more context on Object Shapes, see [Feature: #18776]
Co-Authored-By: Aaron Patterson <tenderlove@ruby-lang.org>
Co-Authored-By: Eileen M. Uchitelle <eileencodes@gmail.com>
Co-Authored-By: John Hawthorn <john@hawthorn.email>
This list is out of date. At least OpenBSD since 2013 does not
allow one user to read the environment variables of a process
run by another user.
While we could try to keep the list updated, I think it's a bad
idea to not use the user/password from the environment, even if
another user on the system could read it. If http_proxy exists
in the environment, and other users can read it, it doesn't
make it more secure for Ruby to ignore it. You could argue that
it encourages poor security practices, but net/http should provide
mechanism, not policy.
Fixes [Bug #18908]
1e4585153d
Previously 9eead86 introduced non-commutativity of platforms, and
later commit 1b9f7f50 changed the behavior of `Gem::Platform.match` to
ensure the callee of `#=~` was the gem platform.
However, when the platform argument is a String, then the callee and
argument of `#=~` are flipped (see docs for `String#=~`), which works
against the fix from 1b9f7f50.
Closes#59383b1fb562e8
Otherwise the timeout thread would be added to the ThreadGroup of the thread that makes the first call to Timeout.timeout .
Fixes bug 19020: https://bugs.ruby-lang.org/issues/19020
Add a test case to make sure the common thread doesn't leak to another ThreadGroup
c4f1385c9a
Object Shapes is used for accessing instance variables and representing the
"frozenness" of objects. Object instances have a "shape" and the shape
represents some attributes of the object (currently which instance variables are
set and the "frozenness"). Shapes form a tree data structure, and when a new
instance variable is set on an object, that object "transitions" to a new shape
in the shape tree. Each shape has an ID that is used for caching. The shape
structure is independent of class, so objects of different types can have the
same shape.
For example:
```ruby
class Foo
def initialize
# Starts with shape id 0
@a = 1 # transitions to shape id 1
@b = 1 # transitions to shape id 2
end
end
class Bar
def initialize
# Starts with shape id 0
@a = 1 # transitions to shape id 1
@b = 1 # transitions to shape id 2
end
end
foo = Foo.new # `foo` has shape id 2
bar = Bar.new # `bar` has shape id 2
```
Both `foo` and `bar` instances have the same shape because they both set
instance variables of the same name in the same order.
This technique can help to improve inline cache hits as well as generate more
efficient machine code in JIT compilers.
This commit also adds some methods for debugging shapes on objects. See
`RubyVM::Shape` for more details.
For more context on Object Shapes, see [Feature: #18776]
Co-Authored-By: Aaron Patterson <tenderlove@ruby-lang.org>
Co-Authored-By: Eileen M. Uchitelle <eileencodes@gmail.com>
Co-Authored-By: John Hawthorn <john@hawthorn.email>
In addition to String values, $LOAD_PATH can also take objects that
respond_to the `to_path` method, like Pathname objects. So `irb` should
be able to handle those objects too.
And if $LOAD_PATH contains objects that can't be converted into String,
`irb` should simply ignore it.
b2f562176b
The warning against `-undefined dynamic_lookup` is just a warning yet,
and many gems seem to pay no attention to warnings. Until it fails
actually, keep it as a migration path, except for standard extension
libraries and bundled extension gems.
Also add --script option to turn the option back on.
Previously there wasn't a way to get an interactive IRB session
and access arguments provided on the command line.
Additionally, handle `-` as script as stdin. In Unix-like tools, `-`
means to take standard input instead of a file. This doesn't
result in exactly the same output for:
```
echo 'p ARGV' > args.rb; irb args.rb a b c
```
and
```
echo 'p ARGV' | irb - a b c
```
Due to how irb handles whether stdin is a tty.
However, this change allows use of `-` as a argument, instead of
giving an unrecognized switch error. This required some small
changes to context.rb (to handle `-` as standard input) and
input-method.rb (to have FileInputMethod accept IO arguments in
addition to strings).
Implements [Feature #15371]
4192683ba2
When extracting files from the tarball, a mode is retrieved from
the header. Occasionally you'll encounter a gem that was packaged
on a system whose permission bits result in a value that is larger
than the value that File.chmod will allow (anything >= 2^16). In
that case the extraction fails with a RangeError, which is pretty
esoteric.
If you extract the tarball with the tar and gunzip utilities, the
file permissions end up being just the bottom 16 bits masked off
from the original value. I've mirrored that behavior here. Per the
tar spec:
> Modes which are not supported by the operating system restoring
> files from the archive will be ignored.
I think that basically means what I've done here.
---
This commit also changes the behavior very slightly with regard to
when the chmod is called. Previously it was called while the file
descriptor was still open, but after the write call.
When write flushes, the file permissions are changed to the mode
value from the File.open call, undoing the changes made by
FileUtils.chmod. CRuby appears to flush the buffer after the
chmod call, whereas TruffleRuby flushes before the chmod call.
So the file permissions can change depending on implementation.
Both implementations end up getting the correct file permissions
for the bottom 9 bits (user, group, world), but differ with
regard to the sticky bit in the next 3.
To get consistent behavior, this commit changes it to close the
file descriptor before attempting to chmod anything, which makes
it consistent because the write flushes in both cases.
22ce076e99
If history file didn't exist when irb was started, @loaded_history_mtime
would be nil. However, if the history file didn't exist before, but it
exists when saving history, that means the history file was modified,
and we should handle it the same way as we handle the other case where
the history file was modified.
Fixes#3888d277aafcb
I want to use more complicated macros with MJIT. For example:
```
# define SHAPE_MASK (((unsigned int)1 << SHAPE_BITS) - 1)
```
This commit adds a simple recursive descent parser that produces an AST
and a small visitor that converts the AST to Ruby.
