Correctness improvements:
* UTF errors are handled safely per spec instead of dangerously truncating
strings.
* There are fewer converter implementations.
Performance improvements:
* The old code did exact buffer length math, which meant doing UTF math twice
on each input string (once for length calculation and another time for
conversion). Exact length math is more complicated when handling errors
properly, which the old code didn't do. The new code does UTF math on the
string content only once (when converting) but risks allocating more than
once. There are heuristics in place to lower the probability of
reallocation in cases where the double math avoidance isn't enough of a
saving to absorb an allocation and memcpy.
* Previously, in UTF-16 <-> UTF-8 conversions, an ASCII prefix was optimized
but a single non-ASCII code point pessimized the rest of the string. The
new code tries to get back on the fast ASCII path.
* UTF-16 to Latin1 conversion guarantees less about handling of out-of-range
input to eliminate an operation from the inner loop on x86/x86_64.
* When assigning to a pre-existing string, the new code tries to reuse the
old buffer instead of first releasing the old buffer and then allocating a
new one.
* When reallocating from the new code, the memcpy covers only the data that
is part of the logical length of the old string instead of memcpying the
whole capacity. (For old callers old excess memcpy behavior is preserved
due to bogus callers. See bug 1472113.)
* UTF-8 strings in XPConnect that are in the Latin1 range are passed to
SpiderMonkey as Latin1.
New features:
* Conversion between UTF-8 and Latin1 is added in order to enable faster
future interop between Rust code (or otherwise UTF-8-using code) and text
node and SpiderMonkey code that uses Latin1.
MozReview-Commit-ID: JaJuExfILM9
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 introduces the machinery needed to generate crash annotations from a YAML
file. The relevant C++ functions are updated to take a typed enum. JavaScript
calls are unaffected but they will throw if the string argument does not
correspond to one of the known entries in the C++ enum. The existing whitelists
and blacklists of annotations are also generated from the YAML file and all
duplicate code related to them has been consolidated. Once written out to the
.extra file the annotations are converted in string form and are no different
than the existing ones.
All existing annotations have been included in the list (and some obsolete ones
have been removed) and all call sites have been updated including tests where
appropriate.
--HG--
extra : source : 4f6c43f2830701ec5552e08e3f1b06fe6d045860
Because XrayTraits::attachExpandoObject operates in the Xray target realm/compartment and we cannot use the Xray wrapper with JSAutoRealm, we pass the caller's global as exclusiveWrapperGlobal and use that.
This also changes XrayWrapper<Base, Traits>::defineProperty to call ensureExpandoObject in the wrapper (instead of target) realm. This didn't matter before, because ensureExpandoObject immediately entered the target realm anyway.
Because getOwnPropertyFromTargetIfSafe operates in the Xray target realm/compartment and we cannot use the Xray wrapper with JSAutoRealm, we pass the caller's global as wrapperGlobal and use that.
Right now, a lot of test code relies on side-effects of SpecialPowers being
loaded into frame script globals. In particular:
- It forces permissive COWs from those scopes, which allows frame scripts to
pass objects from those scopes to unprivileged content that they otherwise
wouldn't.
- It imports a bunch of helper modules and WebIDL globals which would
otherwise not be available.
Fortunately, this seems to only impact test code at this point. But there's a
real down-the-road risk of it impacting shipping code, which ends up working
in automation due to the side-effects of SpecialPowers, but failing in real
world use.
MozReview-Commit-ID: G27eSSOHymX
--HG--
extra : rebase_source : 1702e63fed719fc92def2bdbbb8a7c53572432db
extra : source : 41bedc526dd6ec6b7e8c7be1c832ac60c81d6263
Right now, a lot of test code relies on side-effects of SpecialPowers being
loaded into frame script globals. In particular:
- It forces permissive COWs from those scopes, which allows frame scripts to
pass objects from those scopes to unprivileged content that they otherwise
wouldn't.
- It imports a bunch of helper modules and WebIDL globals which would
otherwise not be available.
Fortunately, this seems to only impact test code at this point. But there's a
real down-the-road risk of it impacting shipping code, which ends up working
in automation due to the side-effects of SpecialPowers, but failing in real
world use.
MozReview-Commit-ID: G27eSSOHymX
--HG--
extra : rebase_source : c528dffe3a54eec75ad6cb358980b783b00eb4a4
The problem we're solving here: getting/entering the realm/global of a cross-compartment wrapper doesn't make sense once there are multiple realms in a compartment and the CCW will be shared by all of them. Because nsXPCWrappedJS can store a CCW, we will no longer be able to use this JSObject to enter the target realm.
What this patch does: we pass a JSContext* to nsXPCWrappedJS::GetNewOrUsed and we use this to store a global object in nsXPCWrappedJS (with the invariant that the object and global stored in nsXPCWrappedJS are same-compartment). Then when we want to enter the nsXPCWrappedJS's target realm, we use this global object instead of the maybe-CCW object. Because we currently still have one realm per compartment and the objects are same-compartment, this is guaranteed to preserve behavior for now.
nsXPCWrappedJS has some code to deal with weak pointers. Fortunately this applies only to root wrappers and root wrappers always store an unwrapped JSObject, so the extra global we store is guaranteed to be marked by the GC in that case (a global object is never collected when there are live JSObjects belonging to the same realm).
This introduces the machinery needed to generate crash annotations from a YAML
file. The relevant functions are updated to take a typed enum (in C++) and an
integer constant (in JavaScript). A JavaScript wrapper around the crash
reporter service is provided to hold the constants. The existing whitelists
and blacklists of annotations are also generated from the YAML file and the
existing duplicate code has been consolidated. Once written out to the .extra
file the annotations are converted in string form and are no different than
the existing ones.
All existing annotations have been included (and some obsolete ones removed)
and all call sites have been updated including tests.
--HG--
extra : rebase_source : b4f0d4bf83c64851028c271d3fab3ebcb6fbcd3e
Summary:
DestructValue acts a lot like CleanupValue, however in addition to normal
cleanup work, it invokes the destructor of complex data types. This is important
to ensure that constructors and destructors are matched for these complex data
types.
CleanupValue is also used to clean up a value without destructing it, so cannot
be modified in-place.
Depends On D2689
Reviewers: mccr8!
Tags: #secure-revision
Bug #: 1480624
Differential Revision: https://phabricator.services.mozilla.com/D2690
Summary:
This macro simplifies code which allows performing an operation on or
extracting information from a particular nsXPTType's native representation.
It is also used in part 2 to implement xpc::DestructValue.
Reviewers: mccr8!
Tags: #secure-revision
Bug #: 1480624
Differential Revision: https://phabricator.services.mozilla.com/D2689
This introduces the machinery needed to generate crash annotations from a YAML
file. The relevant functions are updated to take a typed enum (in C++) and an
integer constant (in JavaScript). A JavaScript wrapper around the crash
reporter service is provided to hold the constants. The existing whitelists
and blacklists of annotations are also generated from the YAML file and the
existing duplicate code has been consolidated. Once written out to the .extra
file the annotations are converted in string form and are no different than
the existing ones.
All existing annotations have been included (and some obsolete ones removed)
and all call sites have been updated including tests.
--HG--
extra : rebase_source : f0e8d229581ac5c0daa0e0454cb258746108e28d
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
Henri Sivonen
Steve Fink
Logan F Smyth
Nicholas Nethercote
Jan de Mooij
Gabriele Svelto
Tooru Fujisawa
Mike Hommey
Jon Coppeard
agashlin@mozilla.com
Brindusan Cristian
Kris Maglione
Masatoshi Kimura
Brian Hackett
Noemi Erli
Dorel Luca
Bogdan Tara
Kristen Wright
Boris Zbarsky
Nika Layzell
Coroiu Cristina