Use the fast canonical type cache for non-generic classes, even if their

Use the fast canonical type cache for non-generic classes, even if their
superclass is generic, in which case the type argument vector is not
necessarily empty, but definitely constant.
Until now, the fast cache was only used for classes without type arguments along
the whole superclass chain.

R=srdjan@google.com

Committed: https://github.com/dart-lang/sdk/commit/fe563306d4e8da64e5ac5c3c176e96e526f6a84e

[regis, 2016-01-04 19:29:00]

regis@google.com changed reviewers:
+ srdjan@google.com

[regis, 2016-01-04 19:29:00]

Happy new year!

[srdjan, 2016-01-04 20:15:24]

Happy New Year!

I do not see how you "Use the fast canonical type cache for non-generic
classes".

https://codereview.chromium.org/1556113002/diff/1/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/1556113002/diff/1/runtime/vm/object.cc#newcod...
runtime/vm/object.cc:2354: return 1;  // List's type parameter not yet parsed.
Should the comment say: List's type parameter may not  have been parsed yet?

https://codereview.chromium.org/1556113002/diff/1/runtime/vm/object.cc#newcod...
runtime/vm/object.cc:15880: ASSERT(!type_class.IsGeneric());  // Super class may
have type arguments.
I do not understand this comment.

[regis, 2016-01-05 11:24:51]

Thanks! PTAL

This change makes a difference for types whose type class is not generic, but
whose superclass (direct or indirect) is generic.
Such types have a type argument vector, but a unique one. Therefore, we can
spare the allocation of an array containing the various canonical types, since
only one canonical type exists.

Examples of such types occurring in the snapshot:
AsciiCodec
Base64Codec
ByteConversionSink
ByteConversionSinkBase
CodeUnits
Encoding
GZipCodec
HtmlEscape
JsonCodec
Latin1Codec
RawDatagramSocket
Runes
Stdin
StringConversionSink
SystemEncoding
Utf8Codec
ZLibCodec
_Base64EncoderSink
_FilterSink
_HttpConnection
_HttpInboundMessage
_HttpIncoming
_IOSinkImpl
_Latin1DecoderSink
_Socket
_StdStream
_UnicodeSubsetEncoder


Note that this change also cleans up a few asserts and also unveils an issue
with canonicalization of type arguments in message snapshots (independent of
this change).

https://codereview.chromium.org/1556113002/diff/1/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/1556113002/diff/1/runtime/vm/object.cc#newcod...
runtime/vm/object.cc:2354: return 1;  // List's type parameter not yet parsed.
On 2016/01/04 20:15:24, srdjan wrote:
> Should the comment say: List's type parameter may not  have been parsed yet?

Done.

https://codereview.chromium.org/1556113002/diff/1/runtime/vm/object.cc#newcod...
runtime/vm/object.cc:15880: ASSERT(!type_class.IsGeneric());  // Super class may
have type arguments.
On 2016/01/04 20:15:24, srdjan wrote:
> I do not understand this comment.

I reverted this change. A type may be non-parameterized, although its superclass
declares type parameters, e.g. class T extends List.
Type T is not generic, but has 1 type argument (always dynamic in this example),
because List has one.
The assert was only relaxed for cases that do not occur anyway in our
implementation.

[srdjan, 2016-01-05 17:36:51]

lgtm

[regis, 2016-01-05 17:51:57]

Description was changed from

==========
Use the fast canonical type cache for non-generic classes, even if their
superclass is generic, in which case the type argument vector is not
necessarily empty, but definitely constant.
Until now, the fast cache was only used for classes without type arguments along
the whole superclass chain.
==========

to

==========
Use the fast canonical type cache for non-generic classes, even if their
superclass is generic, in which case the type argument vector is not
necessarily empty, but definitely constant.
Until now, the fast cache was only used for classes without type arguments along
the whole superclass chain.

R=srdjan@google.com

Committed:
https://github.com/dart-lang/sdk/commit/fe563306d4e8da64e5ac5c3c176e96e526f6a84e
==========

[regis, 2016-01-05 17:51:58]

Committed patchset #2 (id:20001) manually as
fe563306d4e8da64e5ac5c3c176e96e526f6a84e (presubmit successful).