This change replaces kernel AST declarations of fields and functions
with bytecode declarations.
Size of dilp files is reduced by 11-12%.
Startup latency:
Time to the first full frame: 1.945s -> 1.687s
FinalizeClass: 554ms -> 277ms
FinishClassLoading: 296ms -> 156ms
There are following regressions in bytecode mode, which will be fixed
in future:
* dart:mirrors are not supported yet (implementation of mirrors relies
on reading kernel AST in certain cases).
As the result, lib_2/mirrors/* tests fail.
* native extensions are not supported yet (annotations on libraries
and classes in AST are cleaned up as they could reference members
which are now removed from AST).
As the result, standalone_2/entrypoints_verification_test test fails.
* language_2/spread_collections/const_error_test/* tests fail
due to https://github.com/dart-lang/sdk/issues/36286.
Change-Id: I5130f401fd7b84038b136136e7ccc1a6e51b6cea
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/97561
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
This is a major revamp of bytecode metadata format. Now bytecode has
its own serialization mechanisms.
This CL adds 'bytecode component' metadata, which contains bytecode
object table and string table. All references from bytecode (constant
pools) to libraries, classes, members, types and strings now have a new
format. References to frequently used objects are represented as indices
in object table, while rarely used objects are written inline.
This allows VM to cache frequently used objects while reading bytecode.
Representation of strings is aligned with VM - string characters are
stored in separate pools of one-byte and two-byte strings. This allows
VM to avoid UTF-8 decoding and extra copying.
Closure declarations are now explicit. Type parameters no longer require
enslosing scopes when reading/writing them.
Benchmarks:
GenKernelKernelReadAllBytecode (Intel Core i5) +29.84%
GenKernelKernelReadAllBytecode (Intel Xeon) +28.74%
Change-Id: I4b80009733a8f8c038264af74f97c4e094b9e311
Reviewed-on: https://dart-review.googlesource.com/c/85469
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Régis Crelier <regis@google.com>
Reviewed-by: Zach Anderson <zra@google.com>
If a field is initialized with null (either explicitly or implicitly),
field store can be omitted in bytecode. In such case, bytecode should
still convey the information about this initialization to VM for
field guards to work correctly.
Change-Id: I1fd45b858c3c521b97fa5dbffe0e15b1ea75d92f
Reviewed-on: https://dart-review.googlesource.com/76060
Reviewed-by: Zach Anderson <zra@google.com>
Reviewed-by: Régis Crelier <regis@google.com>
Metadata is no longer written ahead of all nodes. Instead, metadata for
each node is written in the same context as the node itself (into a separate
buffer). This allows metadata to contain (serialize) arbitrary nodes
(for example, arbitrary DartTypes) and use serialization context of parent
nodes (such as declared type parameters).
However, with this change metadata looses the ability to reference
arbitrary AST nodes. This ability was overly restricted and had no
practical uses. (It was not possible to reference nodes which are not
reachable from root Component. As a consequence, it was not possible to
write references to arbitrary DartTypes.)
This change aligns the serialization capabilities of metadata with
how kernel AST nodes are serialized.
Change-Id: I027299a33b599b62572eccd4aa7083ad1dd2b3b3
Reviewed-on: https://dart-review.googlesource.com/54481
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Reviewed-by: Jens Johansen <jensj@google.com>
To enable bytecode generation, toggle kEnableKernelBytecode flag at
the beginning of pkg/vm/lib/bytecode/gen_bytecode.dart.
This will also enable generation of bytecode in platform dill files.
Also, bytecode generation can be enabled using --gen-bytecode option of
pkg/vm/tool/gen_kernel.
In kernel binaries, the generated bytecode and constant pool are
placed into 'vm.bytecode' metadata attached to members.
pkg/vm/tool/dump_kernel tool can be used to disassemble
bytecode and print constant pool.
Differences between generated bytecode and original DBC are
described in pkg/vm/lib/bytecode/dbc.dart.
Format of constant pool is described in
pkg/vm/lib/bytecode/constant_pool.dart.
Currently, only a small subset of Dart language is supported.
Bytecode generator will not emit vm.bytecode metadata for a
member if its body has an unsupported operation.
Change-Id: I27d9a361dc779ea115e5676508ee757c1754e05d
Reviewed-on: https://dart-review.googlesource.com/49600
Reviewed-by: Samir Jindel <sjindel@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Reviewed-by: Zach Anderson <zra@google.com>
Reviewed-by: Régis Crelier <regis@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Alexander Markov