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
This list of atoms isn't particularly DOM-ish, and having it in xpcom/ will
help with the next patch.
MozReview-Commit-ID: 1Y3Fhn9lNbh
--HG--
rename : dom/base/nsGkAtomList.h => xpcom/ds/nsGkAtomList.h
rename : dom/base/nsGkAtoms.cpp => xpcom/ds/nsGkAtoms.cpp
rename : dom/base/nsGkAtoms.h => xpcom/ds/nsGkAtoms.h
extra : rebase_source : 0a0f6ab4432e0d58ea4662299b750a8c52325ad5
(Path is actually r=froydnj.)
Bug 1400459 devirtualized nsIAtom so that it is no longer a subclass of
nsISupports. This means that nsAtom is now a better name for it than nsIAtom.
MozReview-Commit-ID: 91U22X2NydP
--HG--
rename : xpcom/ds/nsIAtom.h => xpcom/ds/nsAtom.h
extra : rebase_source : ac3e904a21b8b48e74534fff964f1623ee937c67
Now that nsIAtom is non-scriptable, a .idl file isn't needed.
I made the new nsIAtom.h file by starting with a generated nsIAtom.h file, and
then cleaning it up and removing some stuff that wasn't necessary.
--HG--
extra : rebase_source : 9655fd38984512bd96cf5555048f7774414f6d92
This imports Chromium's `make_dafsa.py` script [1]. It takes in a gperf
formatted file (note: gperf is *not* required) and converts that to a compact
binary representation of the string data in the form of a deterministic
acyclic finite state automaton (DAFSA) [2].
The only change made to the script was to make it handle the arguments our
file generation script passes in to the `main` function.
It also imports the logic for traversing the DAFSA [3] almost verbatim in
`Dafsa.cpp`. A thin wrapper was added so that we can reuse the DAFSA structure
for multiple tables.
The only change made to the original logic was to swap in mozilla style
assertions and rename the not found constant from `kNotFound` to
`Dafsa::kKeyNotFound` in order to avoid a collision with `kNotFound` defined in
our nsString code.
[1] 6ba04a9056/tools/dafsa/make_dafsa.py
[2] https://en.wikipedia.org/wiki/Deterministic_acyclic_finite_state_automaton
[3] a2a90a35aa/net/base/registry_controlled_domains/registry_controlled_domain.cc (72)
MozReview-Commit-ID: Eion9POHZm5
This imports Chromium's `make_dafsa.py` script [1]. It takes in a gperf
formatted file (note: gperf is *not* required) and converts that to a compact
binary representation of the string data in the form of a deterministic
acyclic finite state automaton (DAFSA) [2].
The only change made to the script was to make it handle the arguments our
file generation script passes in to the `main` function.
It also imports the logic for traversing the DAFSA [3] almost verbatim in
`Dafsa.cpp`. A thin wrapper was added so that we can reuse the DAFSA structure
for multiple tables.
The only change made to the original logic was to swap in mozilla style
assertions and rename the not found constant from `kNotFound` to
`Dafsa::kKeyNotFound` in order to avoid a collision with `kNotFound` defined in
our nsString code.
[1] 6ba04a9056/tools/dafsa/make_dafsa.py
[2] https://en.wikipedia.org/wiki/Deterministic_acyclic_finite_state_automaton
[3] a2a90a35aa/net/base/registry_controlled_domains/registry_controlled_domain.cc (72)
MozReview-Commit-ID: Eion9POHZm5
This adds an arena allocator that can be used as a drop-in replacement for
NSPR's PLArena. Example usage for defining an 8-byte aligned allocator that
uses a 4K arena size:
mozilla::ArenaAllocator<4096,8> a;
void* memory = a.Allocate(200);
This adds an intermediate interface, nsIArrayExtensions, that inherits from
nsIArray. This is necessary as nsISupportsArray implements nsIArray as well
so the methods could not just be addded to nsIArray. nsIMutableArray inherits
from nsIArrayExtensions and so any interface that works with an nsIMutableArray
can be updated to return an nsIArrayExtensions.
This will allow interfaces that currently return an nsISupportsArray to instead
return an nsIArrayExtensions and internally work with an nsIMutableArray.
Consumers of these functions will continue to be able to use
nsISupportsArray-like iteration even though they're now working with an
nsIArray.
MozReview-Commit-ID: 9uRjsJbg9Jp
This removes the unnecessary setting of c-basic-offset from all
python-mode files.
This was automatically generated using
perl -pi -e 's/; *c-basic-offset: *[0-9]+//'
... on the affected files.
The bulk of these files are moz.build files but there a few others as
well.
MozReview-Commit-ID: 2pPf3DEiZqx
--HG--
extra : rebase_source : 0a7dcac80b924174a2c429b093791148ea6ac204
The patch removes 455 occurrences of FAIL_ON_WARNINGS from moz.build files, and
adds 78 instances of ALLOW_COMPILER_WARNINGS. About half of those 78 are in
code we control and which should be removable with a little effort.
--HG--
extra : rebase_source : 82e3387abfbd5f1471e953961d301d3d97ed2973
This patch adds another implementation of BaseTimeDuration's ValueCalculator
template parameter that is careful to preserve Forever/-Forever values when
performing arithmetic.
It also defines a typedef for a specialization of BaseTimeDuration that uses
this new ValueCalculator definition.
Nicholas Nethercote
Xidorn Quan
Eric Rahm
Sebastian Hengst
Wes Kocher
Honza Bambas
Benjamin Smedberg
Tom Tromey
Chris Peterson
Benoit Girard
David Major
Brian Birtles
Kyle Huey
Mike Hommey
Birunthan Mohanathas
Andrew McCreight
Ryan VanderMeulen
Ehsan Akhgari
Trevor Saunders
Makoto Kato
Ms2ger
Michael Harrison