While deserializing AOT snapshot, Code objects which do not contain
valuable information besides entry point and stack maps are discarded
and not allocated on the heap (they are replaced with
StubCode::UnknownDartCode()).
PC -> Code/CompressedStackMaps lookup is implemented using a separate
table (InstructionsTable).
Flutter gallery in release-sizeopt mode:
Heap size of snapshot objects: arm -26.89%, arm64 -27.68%
Large Flutter application in release mode with --dwarf-stack-traces:
Heap size of snapshot objects: -24.3%.
Discarded Code objects: 72.5% of all Code objects.
Issue: https://github.com/dart-lang/sdk/issues/44852.
TEST=existing tests; "--dwarf_stack_traces --no-retain_function_objects
--no-retain_code_objects" mode is enabled for a few tests.
Change-Id: I5fe3e283630c8e8f4442319d5dcae38d174dd0d8
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/189560
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Alexander Markov
5129cff930