This reduces memory usage because we only need one allocation instead of two
for the dynamic atom and its chars, and because we don't need to store a
refcount and a size. It precludes sharing of chars between dynamic atoms, but
we weren't benefiting much from that anyway.
This reduces per-process memory usage by up to several hundred KiB on my
Linux64 box.
One consequence of this change is that we need to allocate + copy in
DOMString::SetKnownLiveAtom(), which could make some things slower.
--HG--
extra : rebase_source : ba4065ea31e509dd985c003614199f73def0596c
This was done automatically replacing:
s/mozilla::Move/std::move/
s/ Move(/ std::move(/
s/(Move(/(std::move(/
Removing the 'using mozilla::Move;' lines.
And then with a few manual fixups, see the bug for the split series..
MozReview-Commit-ID: Jxze3adipUh
For nsCSSAnonBoxes.cpp, nsCSSPseudoElements.cpp, nsDirectoryService.cpp, the
corresponding .h file includes nsStaticAtom.h. For the other files in this
patch, nsStaticAtom.h is not needed at all.
MozReview-Commit-ID: IpMmbXwZHhu
--HG--
extra : rebase_source : 46d0a6b40a41ee233adad7c205cf907fa27de34a
NullPrincipal::Create() (will null OA) may cause an OriginAttributes bypass.
We change Create() so OriginAttributes is no longer optional, and rename
Create() with no arguments to make it more explicit about what the caller is doing.
MozReview-Commit-ID: 7DQGlgh1tgJ
Currently static atoms are stored on the heap, but their char buffers are
stored in read-only static memory.
This patch changes the representation of nsStaticAtom (thus making it a
non-trivial subclass of nsAtom). Instead of a pointer to the string, it now has
an mStringOffset field which is a 32-bit offset to the string. (This requires
placement of the string and the atom within the same object so that the offset
is known to be small. The docs and macros in nsStaticAtom.h handle that.)
Static and dynamic atoms now store their chars in different ways: nsStaticAtom
stores them inline, nsDynamicAtom has a pointer to separate storage. So
`mString` and GetStringBuffer() move from nsAtom to nsDynamicAtom.
The change to static atoms means they can be made constexpr and stored in
read-only memory instead of on the heap. On 64-bit this reduces the per-process
overhead by 16 bytes; on 32-bit the saving is 12 bytes. (Further reductions
will be possible in follow-up patches.)
The increased use of constexpr required multiple workarounds for MSVC.
- Multiple uses of MOZ_{PUSH,POP}_DISABLE_INTEGRAL_CONSTANT_OVERFLOW_WARNING to
disable warnings about (well-defined!) overflow of unsigned integer
arithmetic.
- The use of -Zc:externConstexpr on all files defining static atoms, to make
MSVC follow the C++ standard(!) and let constexpr variables have external
linkage.
- The use of -constexpr:steps300000 to increase the number of operations
allowed in a constexpr value, in order to handle gGkAtoms, which requires
hashing ~2,500 atom strings.
The patch also changes how HTML5 atoms are handled. They are now treated as
dynamic atoms, i.e. we have "dynamic normal" atoms and "dynamic HTML5 atoms",
and "dynamic atoms" covers both cases, and both are represented via
nsDynamicAtom. The main difference between the two kinds is that dynamic HTML5
atoms still aren't allowed to be used in various operations, most notably
AddRef()/Release(). All this also required moving nsDynamicAtom into the header
file.
There is a slight performance cost to all these changes: now that nsStaticAtom
and nsDynamicAtom store their chars in different ways, a conditional branch is
required in the following functions: Equals(), GetUTF16String(),
WeakAtom::as_slice().
Finally, in about:memory the "explicit/atoms/static/atom-objects" value is no
longer needed, because that memory is static instead of heap-allocated.
MozReview-Commit-ID: 4AxPv05ngZy
Most of the noise is from the fact that clang-format on parser/html/*.{h,cpp}
reformatted all sorts of stuff. Not running it caused lots of format changes
from the generator... I guess we changed the format rules since the last time
this got run?
MozReview-Commit-ID: IA2G87zUIKN
The atoms in nsHTMLTags are a subset of nsGkAtoms, which means that
sTagAtomTable[] currently ends up holding duplicate pointers to the same static
atoms.
This patch removes sTagAtomTable[]. The only place that used sTagAtomTable[]
was nsHTMLTags::AddRefTable(). It now instead calls NS_GetStaticAtom() to get
the static atoms registered by nsGkAtoms.
The patch also moves some checking of sTagNames from RegisterAtoms() (which is
removed) to AddRefTable().
All this reduces the number of duplicate static atoms from 148 to 12.
MozReview-Commit-ID: 14qXYeoorFr
* * *
[mq]: foo
MozReview-Commit-ID: AgQbXlcvWrt
By removing the "Atom" suffix, which is redundant.
MozReview-Commit-ID: 4MCX9Icfjrw
--HG--
extra : rebase_source : c3c759a508a8938b59d36dbb20448d2964b98c91
This converts nsHTMLTags hashtables from PLHash to nsDataHashtable which
gives us both type safety and simpler code. Addtionally `gTagTable` now holds
a nsString instead of a raw char16_t pointer, this has the benefit of the
strings knowing their sizes allowing for more efficient comparisons. We avoid
heap allocations in the nsString by using `AssignLiteral` with the string from
the static string array.
--HG--
extra : rebase_source : 3ab6409de5e933beb868a0b371dff81e56df0810
Nicholas Nethercote
Andi-Bogdan Postelnicu
Joel Maher
Emilio Cobos Álvarez
Boris Zbarsky
Adrian Wielgosik
Andrea Marchesini
Chris Peterson
Sebastian Hengst
Tristan Bourvon
Sylvestre Ledru
Masatoshi Kimura
Tiberius Oros
Margareta Eliza Balazs
Gurzau Raul
Tom Ritter
Miko Mynttinen
Tooru Fujisawa
Eric Rahm