dart-sdk/runtime
Martin Kustermann ed5ad5c087 Add CLI tool for analyzing Dart VM heapsnapshots
This CL adds an interactive command line tool to analyze
heapsnapshots generated by the Dart VM.

The tool works by operating on sets of objects. It supports operations
like users, transitive closure, union, ...

An example usage that loads snapshot, finds all live objects, finds
the empty lists in them and prints retainers of the empty lists:

    ```
    % dart bin/explore.dart

    (hsa) load foo.heapsnapshot

    (hsa) all = closure roots
    (hsa) stat all
          size       count     class
      --------   --------  --------
       43861 kb    8371    _Uint8List dart:typed_data
         ...
      --------   --------  --------
      108904 kb  400745

    (hsa) empty-lists = dfilter (filter all _List) ==0
    (hsa) empty-growable-lists = filter (users empty-lists) _GrowableList

    (hsa) retain empty-growable-lists
    There are 5632 retaining paths of
    _GrowableList (dart:core)
    ⮑ ・UnlinkedLibraryImportDirective.configurations (package:analyzer/src/dart/analysis/unlinked_data.dart)
        ⮑ ﹢_List (dart:core)
            ⮑ ・...
    ```

For now the tool lives only in dart-lang/sdk.

TEST=pkg/heapsnapshot/test/*_test.dart

Change-Id: I671c2e3ca770e1a5aa3e590e850a5694070b4c3a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/261100
Reviewed-by: Tess Strickland <sstrickl@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
2022-09-30 14:15:01 +00:00
..
bin
docs
include
lib
observatory
observatory_2
platform
tests
third_party
tools
vm
.clang-tidy
.gitignore
BUILD.gn
codereview.settings
configs.gni
CPPLINT.cfg
OWNERS
PRESUBMIT.py
runtime_args.gni