ruby.git/vm_callinfo.h, branch v3_2_11

Prevent wrong integer expansion

2022-10-13T15:14:04+00:00

`(attr_index + 1)` leads to wrong integer expansion on 32-bit machines
(including Solaris 10 CI) because `attr_index_t` is uint16_t.

http://rubyci.s3.amazonaws.com/solaris10-gcc/ruby-master/log/20221013T080004Z.fail.html.gz
```
  1) Failure:
TestRDocClassModule#test_marshal_load_version_2 [/export/home/users/chkbuild/cb-gcc/tmp/build/20221013T080004Z/ruby/test/rdoc/test_rdoc_class_module.rb:493]:
<[doc: [doc (file.rb): [para: "this is a comment"]]]> expected but was
<[doc: [doc (file.rb): [para: "this is a comment"]]]>.

  2) Failure:
TestRDocStats#test_report_method_line [/export/home/users/chkbuild/cb-gcc/tmp/build/20221013T080004Z/ruby/test/rdoc/test_rdoc_stats.rb:460]:
Expected /\#\ in\ file\ file\.rb:4/ to match "The following items are not documented:\n" +
"\n" +
"  class C # is documented\n" +
"\n" +
"    # in file file.rb\n" +
"    def m1; end\n" +
"\n" +
"  end\n" +
"\n" +
"\n".

  3) Failure:
TestRDocStats#test_report_attr_line [/export/home/users/chkbuild/cb-gcc/tmp/build/20221013T080004Z/ruby/test/rdoc/test_rdoc_stats.rb:91]:
Expected /\#\ in\ file\ file\.rb:3/ to match "The following items are not documented:\n" +
"\n" +
"  class C # is documented\n" +
"\n" +
"    attr_accessor :a # in file file.rb\n" +
"\n" +
"  end\n" +
"\n" +
"\n".
```

Initialize shape attr index also in non-markable CC

2022-10-12T16:14:55+00:00

Do not read cached_id from callcache on stack

2022-10-12T11:28:24+00:00

The inline cache is initialized by vm_cc_attr_index_set only when
vm_cc_markable(cc). However, vm_getivar attempted to read the cache
even if the cc is not vm_cc_markable.

This caused a condition that depends on uninitialized value.
Here is an output of valgrind:

```
==10483== Conditional jump or move depends on uninitialised value(s)
==10483==    at 0x4C1D60: vm_getivar (vm_insnhelper.c:1171)
==10483==    by 0x4C1D60: vm_call_ivar (vm_insnhelper.c:3257)
==10483==    by 0x4E8E48: vm_call_symbol (vm_insnhelper.c:3481)
==10483==    by 0x4EAD8C: vm_sendish (vm_insnhelper.c:5035)
==10483==    by 0x4C62B2: vm_exec_core (insns.def:820)
==10483==    by 0x4DD519: rb_vm_exec (vm.c:0)
==10483==    by 0x4F00B3: invoke_block (vm.c:1417)
==10483==    by 0x4F00B3: invoke_iseq_block_from_c (vm.c:1473)
==10483==    by 0x4F00B3: invoke_block_from_c_bh (vm.c:1491)
==10483==    by 0x4D42B6: rb_yield (vm_eval.c:0)
==10483==    by 0x259128: rb_ary_each (array.c:2733)
==10483==    by 0x4E8730: vm_call_cfunc_with_frame (vm_insnhelper.c:3227)
==10483==    by 0x4EAD8C: vm_sendish (vm_insnhelper.c:5035)
==10483==    by 0x4C6254: vm_exec_core (insns.def:801)
==10483==    by 0x4DD519: rb_vm_exec (vm.c:0)
==10483==
```

In fact, the CI on FreeBSD 12 started failing since ad63b668e22e21c352b852f3119ae98a7acf99f1.

```
gmake[1]: Entering directory '/usr/home/chkbuild/chkbuild/tmp/build/20221011T163003Z/ruby'
/usr/home/chkbuild/chkbuild/tmp/build/20221011T163003Z/ruby/lib/optparse.rb:924:in `complete': undefined method `complete' for nil:NilClass (NoMethodError)
	from /usr/home/chkbuild/chkbuild/tmp/build/20221011T163003Z/ruby/lib/optparse.rb:1816:in `block in visit'
	from /usr/home/chkbuild/chkbuild/tmp/build/20221011T163003Z/ruby/lib/optparse.rb:1815:in `reverse_each'
	from /usr/home/chkbuild/chkbuild/tmp/build/20221011T163003Z/ruby/lib/optparse.rb:1815:in `visit'
	from /usr/home/chkbuild/chkbuild/tmp/build/20221011T163003Z/ruby/lib/optparse.rb:1847:in `block in complete'
	from /usr/home/chkbuild/chkbuild/tmp/build/20221011T163003Z/ruby/lib/optparse.rb:1846:in `catch'
	from /usr/home/chkbuild/chkbuild/tmp/build/20221011T163003Z/ruby/lib/optparse.rb:1846:in `complete'
	from /usr/home/chkbuild/chkbuild/tmp/build/20221011T163003Z/ruby/lib/optparse.rb:1640:in `block in parse_in_order'
	from /usr/home/chkbuild/chkbuild/tmp/build/20221011T163003Z/ruby/lib/optparse.rb:1632:in `catch'
	from /usr/home/chkbuild/chkbuild/tmp/build/20221011T163003Z/ruby/lib/optparse.rb:1632:in `parse_in_order'
	from /usr/home/chkbuild/chkbuild/tmp/build/20221011T163003Z/ruby/lib/optparse.rb:1626:in `order!'
	from /usr/home/chkbuild/chkbuild/tmp/build/20221011T163003Z/ruby/lib/optparse.rb:1732:in `permute!'
	from /usr/home/chkbuild/chkbuild/tmp/build/20221011T163003Z/ruby/lib/optparse.rb:1757:in `parse!'
	from ./ext/extmk.rb:359:in `parse_args'
	from ./ext/extmk.rb:396:in `'
```

This change adds a guard to read the cache only when vm_cc_markable(cc).
It might be better to initialize the cache as INVALID_SHAPE_ID when the
cc is not vm_cc_markable.

Make inline cache reads / writes atomic with object shapes

2022-10-11T15:40:56+00:00

Prior to this commit, we were reading and writing ivar index and
shape ID in inline caches in two separate instructions when
getting and setting ivars. This meant there was a race condition
with ractors and these caches where one ractor could change
a value in the cache while another was still reading from it.

This commit instead reads and writes shape ID and ivar index to
inline caches atomically so there is no longer a race condition.

Co-Authored-By: Aaron Patterson 
Co-Authored-By: John Hawthorn

Revert "Revert "This commit implements the Object Shapes technique in CRuby.""

2022-10-11T15:40:56+00:00

This reverts commit 9a6803c90b817f70389cae10d60b50ad752da48f.

Revert "This commit implements the Object Shapes technique in CRuby."

2022-09-30T23:01:50+00:00

This reverts commit 68bc9e2e97d12f80df0d113e284864e225f771c2.

This commit implements the Object Shapes technique in CRuby.

2022-09-28T15:26:21+00:00

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 
Co-Authored-By: Eileen M. Uchitelle 
Co-Authored-By: John Hawthorn

Revert this until we can figure out WB issues or remove shapes from GC

2022-09-26T23:10:11+00:00

Revert "* expand tabs. [ci skip]"

This reverts commit 830b5b5c351c5c6efa5ad461ae4ec5085e5f0275.

Revert "This commit implements the Object Shapes technique in CRuby."

This reverts commit 9ddfd2ca004d1952be79cf1b84c52c79a55978f4.

This commit implements the Object Shapes technique in CRuby.

2022-09-26T16:21:30+00:00

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 
Co-Authored-By: Eileen M. Uchitelle 
Co-Authored-By: John Hawthorn

Extract vm_ic_entry API to mimic vm_cc behavior

2022-07-18T19:44:01+00:00