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asiva f81a402aa1 "[SDK/VM] - Rename dart_precompiled_runtime to dartaotruntime, ensures we have a uniform name for the executable between the build directories and the SDK directory"

Fixed golem breakage by temporarily copying dartaotruntime to dart_precompiled_runtime

This reverts commit 75e6a748f7.

TEST=ci

Original change's description:
> Revert "[SDK/VM] - Rename dart_precompiled_runtime to dartaotruntime, ensures we have a uniform name for the executable between the build directories and the SDK directory"
>
> This reverts commit 1b331d05c2.
>
> Reason for revert: golem builds are failing
>
> Original change's description:
> > [SDK/VM] - Rename dart_precompiled_runtime to dartaotruntime, ensures we have a uniform name for the executable between the build directories and the SDK directory
> >
> > TEST=ci
> >

Change-Id: Id0f383eabb496c06c0acebc639c8e3b056ba82d0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/393781
Commit-Queue: Siva Annamalai <asiva@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>

2024-11-06 03:10:31 +00:00

2.4 KiB

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AOT code size analysis

The Dart VM's AOT compiler has support for emitting binary size information for all the code that gets generated. This information can then be visualized.

Telling the AOT compiler to generate binary size information

Our AOT compiler accepts an extra --print-instructions-sizes-to=sizes.json flag. If supplied the AOT compiler will emit binary size information for all generated functions to sizes.json.

This flag can be passed to gen_snapshot directly, or to the various wrapper scripts (e.g. pkg/vm/tool/precompiler2):

% tools/build.py -mrelease -ax64 runtime runtime_precompiled
% pkg/vm/tool/precompiler2 --print-instructions-sizes-to=hello_sizes.json hello.dart hello.dart.aot

In Flutter, pass this argument to flutter build:

% flutter build aot --release --extra-gen-snapshot-options=--print-instructions-sizes-to=hello_sizes.json

Visualizing the information from the binary size json file

To visualize the information emitted by the AOT compiler one can use our binary size analysis tool:

% dart pkg/vm/bin/snapshot_analysis.dart treemap hello_sizes.json hello_sizes
Generated file:///.../sdk/hello_sizes/index.html
% chrome hello_sizes/index.html

Comparing the sizes of two AOT builds

To visualize the differences between two AOT builds one can use our binary size comparison tool:

% dart pkg/vm/bin/snapshot_analysis.dart compare app-sizes--before.json app-sizes--after.json

+---------+--------+--------------+
| Library | Method | Diff (Bytes) |
+---------+--------+--------------+
...

Object-level data

gen_snapshot also accepts an extra --write-v8-snapshot-profile-to=hello.heapsnapshot flag. If supplied the AOT compiler will emit snapshot size information for all objects in the snapshot to hello.heapsnapshot in V8 snapshot format.