This commit adds `SharedImmutableStringsCache` which allows for de-duplication
and sharing of immutable strings between threads and JSRuntimes.
Each JSRuntime gets a SharedImmutableStringsCache member, but the accessor
always returns the parent runtime's cache. The caches in child JSRuntime's are
not wasting space, however, as initialization and allocation of the table
happens lazily within SharedImmutableStringsCache.
Furthermore, this commit removes `js::ScriptSource::Parent` and the
`CompressedSourceSet`. They are unnecessary because source text is always shared
via the parent runtime's `SharedImmutableStringsCache` now.
js::ObjectOps is often all null. When it's not all null, it's often duplicated
many times among classes. By pulling it out into its own struct, and using a
(possibly null) pointer in js::Class, we can save 208 KiB per process on
64-bit, and half that on 32-bit.
--HG--
extra : rebase_source : 5be8fe45f652392571b8a6d7b63777cbafba6ae4
Using a simple |const char*| is more memory-efficient than allocating a
JS string. We still have to allocate the JS string for passing things
into JS, but ideally we will be able to move the point of allocation
much closer to where it's actually needed, rather than indiscriminantly
doing it all the time.
Using a simple |const char*| is more memory-efficient than allocating a
JS string. We still have to allocate the JS string for passing things
into JS, but ideally we will be able to move the point of allocation
much closer to where it's actually needed, rather than indiscriminantly
doing it all the time.
There can be multiple compartments within the same zone, only one of which is a
debuggee. In this scenario, CCWs from other compartments into the debuggee
compartment should be traced and treated as roots. Therefore, dealing with CCWs
at the JS::Zone level is incorrect, and this patch changes the granularity level
to JSCompartments. If you look at the callers and uses of the function, it makes
much more sense now.
Additionally, it renames `JS_TraceIncomingCCWs` to `JS::TraceIncomingCCWs`.
--HG--
rename : devtools/shared/heapsnapshot/tests/gtest/DoesCrossZoneBoundaries.cpp => devtools/shared/heapsnapshot/tests/gtest/DoesCrossCompartmentBoundaries.cpp
rename : devtools/shared/heapsnapshot/tests/gtest/DoesntCrossZoneBoundaries.cpp => devtools/shared/heapsnapshot/tests/gtest/DoesntCrossCompartmentBoundaries.cpp
Using a simple |const char*| is more memory-efficient than allocating a
JS string. We still have to allocate the JS string for passing things
into JS, but ideally we will be able to move the point of allocation
much closer to where it's actually needed, rather than indiscriminantly
doing it all the time.
The start node was being marked "visited" at the start of the traversal, but
this broke the invariant that if we come across a target node that is marked
"visited" then we had better have an entry for it in our results map. In order
to maintain this invariant and stop triggering these assertion failures, this
commit stops marking the start node as "visited" right off the bat.
Redoes object element measurement and reporting:
- Adds "non-heap/elements/shared", which reports a (size / refcount)
measurement. Previously these measurements went into
"non-heap/elements/mapped" and the full size would be erroneously reported
for every thread sharing the buffer.
- Renames "non-heap/elements/mapped" as "non-heap/elements/normal".
- Renames "malloc-heap/elements/non-asm.js" as "malloc-heap/elements/normal".
- Leaves "{malloc,non}-heap/elements/asm.js" unchanged.
--HG--
extra : rebase_source : cd1a660000fcb95674b317098be2dfec792b2c8e
It's gone from 4,096 bytes per JS thread to 72 bytes per thread. (Also, the
old code only measured the DtoaState for the main thread.)
--HG--
extra : rebase_source : bfe0772b8c760a45ca3665e2c0939b121189520a
