| commit | e8e9e1d15216788d4112e40f4408c52455d11113 | [log] [tgz] |
|---|---|---|
| author | Daco Harkes <dacoharkes@google.com> | Mon Sep 06 06:28:59 2021 +0000 |
| committer | Daco Harkes <dacoharkes@google.com> | Mon Sep 06 06:28:59 2021 +0000 |
| tree | 305ab06cf4f36aa8f7e399c3d5951cad17e4784e | |
| parent | 32f6f94ab580945245b21c4d534cdc15f4f55499 [diff] |
[vm] Introduce immutable maps and sets in backend This CL introduces immutable maps and sets in the VM backend but does not yet target them from the frontend. The changes are tested by unit tests constructing these immutable maps and sets. This CL introduces immutable variants of the hash map and set in compact_hash.dart and recognizes them in the VM. The immutable ones use a different mixin with a different recognized method for accessing members. * Data list is an immutable list with a different cid. (Otherwise the optimizer notices that immutable and mutable lists cannot be equal.) * Index is a nullable mutable typed data. (Otherwise optimizer removes necessary null checks.) * Index should use a store-release barrier when written to. Multiple isolates might lazily compute the index for const sets and maps. This is fine because all identityHashCodes and hashCodes are guaranteed to be race-free. The later isolates will override the index pointer with an identical index. This CL does not introduce support for using these immutable maps and sets in AOT (clustered_snapshot) and in messages to other isolates (message_snapshot) because that is harder to test with unit tests. That will be added in the follow-up CL. Design doc: go/dart-vm-const-maps TEST=runtime/vm/object_test.cc Bug: https://github.com/dart-lang/sdk/issues/45908 Change-Id: I4042179c15e8b37692d3255655351c01c7124991 Cq-Include-Trybots: luci.dart.try:analyzer-nnbd-linux-release-try,app-kernel-linux-debug-x64-try,dart-sdk-linux-try,front-end-nnbd-linux-release-x64-try,pkg-linux-debug-try,vm-canary-linux-debug-try,vm-kernel-asan-linux-release-x64-try,vm-kernel-checked-linux-release-x64-try,vm-kernel-linux-debug-x64c-try,vm-kernel-linux-debug-x64-try,vm-kernel-linux-debug-simarm64c-try,vm-kernel-nnbd-linux-release-simarm-try,vm-kernel-optcounter-threshold-linux-release-x64-try,vm-kernel-precomp-android-release-arm_x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-linux-debug-x64c-try,vm-kernel-reload-linux-debug-x64-try,vm-kernel-reload-rollback-linux-debug-x64-try,vm-precomp-ffi-qemu-linux-release-arm-try,vm-kernel-precomp-linux-debug-simarm_x64-try,vm-kernel-precomp-linux-debug-x64-try Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/210860 Reviewed-by: Martin Kustermann <kustermann@google.com>
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