Tess Strickland
4f925105cf
Previously, the VM used a linear array to cache previous instantiations of a type arguments object. Now once the cache hits a certain number of occupied entries, the VM changes to using a hash-based approach. The InstantiateTypeArguments stubs have not yet been updated to traverse the hash-based cache, so once the cache has grown too large, all attempts at instantiations, even those that are in the cache, go to the runtime. Thus, until the stubs are updated, this is only an improvement if the cost of traversing the linear cache dominates the cost of making a runtime call. Our benchmarks see a ~40% performance regression for hash-based caches of size 100 but a ~400% performance improvement for hash-based caches of size 1000. Thus, we currently split the difference and set the maximum size of linear caches to 500. TEST=vm/cc/TypeArguments_Cache_ManyInstantiations Bug: https://github.com/dart-lang/sdk/issues/48344 Change-Id: I7f1376943523bb5bcd8b175cfb1936779ea73d60 Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-dwarf-linux-product-x64-try,vm-kernel-precomp-linux-product-x64-try,vm-kernel-precomp-linux-release-x64-try,vm-kernel-precomp-nnbd-mac-release-arm64-try,vm-kernel-precomp-nnbd-linux-release-simarm_x64-try,vm-kernel-precomp-linux-release-simarm-try,vm-kernel-precomp-nnbd-linux-release-x64-try,vm-kernel-precomp-nnbd-linux-release-simarm64-try,vm-kernel-precomp-nnbd-linux-debug-simriscv64-try,vm-kernel-precomp-tsan-linux-release-x64-try,vm-kernel-tsan-linux-release-x64-try Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/265325 Reviewed-by: Martin Kustermann <kustermann@google.com> Reviewed-by: Ryan Macnak <rmacnak@google.com> Commit-Queue: Tess Strickland <sstrickl@google.com>
Dart VM Compilation Pipeline
This folder contains Dart VM compilation pipeline.
Compilation pipeline is mainly responsible for converting AST or Kernel AST into IL flow graphs and then generating native code from IL.
It has the following structure:
| Directory | What goes there |
|---|---|
assembler/ |
Assemblers and disassemblers |
backend/ |
IL based compilation backend: optimization passes and architecture specific code generation rules |
frontend/ |
Frontends responsible for converting AST into IL |
jit/ |
JIT specific passes and compilation pipeline entry points |
aot/ |
AOT specific passes and compilation pipeline entry points |
. |
Shared code or code without clear designation. |
Currently there are no layering restrictions and components from different subfolders can reference each other.