Entry storage allocation now occurs on the first lookupForAdd()/put()/putNew().
This removes the need for init() and initialized(), and matches how
PLDHashTable/nsTHashtable work. It also removes the need for init() functions
in a lot of types that are built on top of mozilla::Hash{Map,Set}.
Pros:
- No need for init() calls and subsequent checks.
- No memory allocated for empty tables, which are not that uncommon.
Cons:
- An extra branch in lookup() and lookupForAdd(), but not in put()/putNew(),
because the existing checkOverloaded() can handle it.
Specifics:
- Construction now can take a length parameter.
- init() is removed. Explicit length-setting, when necessary, now occurs in the
constructors.
- initialized() is removed.
- capacity() now returns zero when the entry storage is absent.
- lookupForAdd() is no longer `const`, because it can instantiate the storage,
which requires modifications.
- lookupForAdd() can now return an invalid AddPtr in two cases:
- old: hashing failure (due to OOM in the hasher)
- new: OOM while instantiating entry storage
The existing failure handling paths for the old case work for the new case.
- clear(), finish(), and clearAndShrink() are replaced by clear(), compact(),
and reserve(). The old compactIfUnderloaded() is also removed.
- Capacity computation code is now in its own functions, bestCapacity() and
hashShift(). setTableSizeLog2() is removed.
- uint32_t is used throughout for capacities, instead of size_t, for
consistency with other similar values.
- changeTableSize() now takes a capacity instead of a deltaLog2, and it can now
handle !mTable.
Measurements:
- Total source code size is reduced by over 900 lines. Also, lots of existing
lines got shorter (i.e. two checks were reduced to one).
- Executable size barely changed, down by 2 KiB on Linux64. The extra branches
are compensated for by the lack of init() calls.
- Speed changed negligibly. The instruction count for Bench_Cpp_MozHash
increased from 2.84 billion to 2.89 billion but any execution time change was
well below noise.
This refactors gc::Cell derived types to start with a uintptr_t-sized
field with the low bits reserved for the GC and uses these bits for
relocation mechanism.
- JSString now stores flags in a uintptr_t. On 32-bit platforms, a
second field is used to hold length.
- Redefine JSString flag bit positions to avoid cell reserved bits.
- Forwarded Cells are now indicated by a reserved flag instead of a
magic invalid-pointer-like value.
- gc::RelocationOverlay now extends gc::Cell
- Update js::Symbol, js::Scope and js::BigInt fields to be compatible.
MozReview-Commit-ID: Cs5OavbHmqK
Add accessor methods so that underlying storage strategy can be changed
later. This patch should not change current behaviour.
MozReview-Commit-ID: IRA53TQShe6
Because (a) it's kinda weird, and (b) only used in a single test, where it can
be easily replaced with a vanilla add().
MozReview-Commit-ID: L4RoxFb7yGG
--HG--
extra : rebase_source : 515a5ede5d417686907345ad9069c6a41669dd17
It's identical to mozilla::CStringHasher.
Also fix a comment at the top of HashTable.h about CStringHasher.
--HG--
extra : rebase_source : 92176c4f6ea8041f309764b4ce0271a494853a7b
In the old days we could only share a SharedArrayBuffer, but now we
can also share WasmMemory and WasmModule objects. Rename the shell's
get/setSharedArrayBuffer as get/setSharedObject and generalize them to
handle the new types.
Leave the old names in place as aliases of the new names.
We rename /some/ uses of get/setSharedArrayBuffer in existing test
cases, but leave uses in test262 alone; we need to upstream those more
carefully.
--HG--
extra : rebase_source : 5ca04306a739249a70fc4aa8734b08e16d62f7d4
extra : source : fcd471c23cf3c1374541df766fd5aea0628fb2a5
In PLDHashTable the equivalent functions have a "Shallow" prefix, which makes
it clear that they don't measure things hanging off the table. This patch makes
mozilla::Hash{Set,Map} do likewise.
MozReview-Commit-ID: 3kwCJynhW7d
--HG--
extra : rebase_source : 9c03d11f376a9fd4cfd5cfcdc0c446c00633b210
The main change is that the patch copies js/public/HashTable.h to
mfbt/HashTable.h, and then changes it as follows.
- Changes `js` namespaces to `mozilla` (and removes some now-unnecessary
`mozilla::` qualifiers).
- Changes the default AllocPolicy from the SpiderMonkey-specific
`TempAllocPolicy` to the generic `MallocAllocPolicy`.
- Adds `#include "AllocPolicy.h"` (like mfbt/Vector.h).
- Changes `JS_DEBUG` use to `DEBUG`.
- Minor comment updates, as necessary.
js/public/HashTable.h is now tiny, holding just a few renamings of things from
the `mozilla` namespace into the `js` namespace to minimize churn elsewhere.
(Those renamings keep `TempAllocPolicy` as the default AllocPolicy for
js::Hash{Set,Map}.)
Also, various template specializations had to be moved from the `js` namespace
to the `mozilla` namespace to avoid compile errors.
MozReview-Commit-ID: GS9Qn9YeYDA
--HG--
rename : js/public/HashTable.h => mfbt/HashTable.h
Currently we have three ways of representing hash values.
- uint32_t: used in HashFunctions.h.
- PLDHashNumber: defined in PLDHashTable.{h,cpp}.
- js::HashNumber: defined in js/public/Utility.h.
Functions that create hash values with functions from HashFunctions.h use a mix
of these three types. It's a bit of a mess.
This patch introduces mozilla::HashNumber, and redefines PLDHashNumber and
js::HashNumber as synonyms. It also changes HashFunctions.h to use
mozilla::HashNumber throughout instead of uint32_t.
This leaves plenty of places that still use uint32_t that should use
mozilla::HashNumber or one of its synonyms, but I didn't want to tackle that
now.
The patch also:
- Does similar things for the constants defining the number of bits in each
hash number type.
- Moves js::HashNumber from Utility.h to HashTable.h, which is a better spot
for it. (This required changing the signature of ScrambleHashCode(); that's
ok, it'll get moved by the next patch anyway.)
MozReview-Commit-ID: EdoWlCm7OUC
--HG--
extra : rebase_source : 5b92c0c3560eb56850cd8832f8ee514d25e3c16f
Because it's more precise, and gives us more consistency.
MozReview-Commit-ID: BLYXYSHgZ7v
--HG--
extra : rebase_source : 527379499a7f2868e032982d7967005df6599bf1
Added a new CoarseType that refers to DOM nodes. Updated the trees to represent the CoarseType. Created a new type of count in the heap snapshot that sorts the data by a more descriptive type name. Created the descriptive in JS::ubi::Base.
--HG--
extra : histedit_source : be24efa4d2ccb85e82046d7cf7d2c3a1e13b1fd7
Created a runtime hook to handle DOM nodes. Specialized ubi::Concrete for nsINode-inheriting objects. Displayed outgoing nsISupports* edges on reflector JSObjects. Generated outgoing child edges from nsINodes by examining their children. Updated the UbiNodeCensus to ignore zone checks if there is no zone to be found in a node.
--HG--
extra : rebase_source : 319dccb3277a39e51a79588eac9c8f2b4ff97c2f
Created a runtime hook to handle DOM nodes. Specialized ubi::Concrete for nsINode-inheriting objects. Displayed outgoing nsISupports* edges on reflector JSObjects. Generated outgoing child edges from nsINodes by examining their children. Updated the UbiNodeCensus to ignore zone checks if there is no zone to be found in a node.
This patch adds new functions taking the arena parameter rather than overloading
existing functions, because there are already overloads of calloc that take
two size_t parameters (which arena_id_t is an alias for), so it couldn't have
been done that way, and malloc and realloc needed to be consistent with calloc.
MozReview-Commit-ID: 1MUXoCUgJWO
--HG--
extra : rebase_source : 16261ba4e802efa0bc65878d490ae9b62aa35797
Separated SimpleEdgeRange into the new UbiNodeUtils.h, updated build files, changed SimpleEdgeRange::init to SimpleEdgeRange::addTracerEdges, created bool addEdge to add new edges to the vector.
Bug 1465505 moved from PRJ_Now to mozilla::TimeStamp. As a side effect,
it introduced a few extra global constructors calls.
This patch fixes it.
MozReview-Commit-ID: 9VX83JZIyds
--HG--
extra : rebase_source : 01a22a8eea3ab224dbaa1a93d2a73ebb9ab6b6ea
IsCrossCompartmentWrapper calls IsWrapper and then had an out-of-line call to Wrapper::wrapperHandler, but that's just loading the proxy handler and we already did that in IsWrapper. Having Wrapper::wrapperHandler in the header file means the compiler can compile IsCrossCompartmentWrapper much better.
Matthew Gaudet
André Bargull
Nicholas Nethercote
Boris Zbarsky
Ted Campbell
Jon Coppeard
Lars T Hansen
Narcis Beleuzu
Markus Stange
Tooru Fujisawa
Andreea Pavel
Kristen Wright
Benjamin Bouvier
shindli
Brian Hackett
Csoregi Natalia
Margareta Eliza Balazs
Andrea Marchesini
Matt Howell
Wander Lairson Costa
Jan de Mooij