Bug 1207519 added maybe_pod_* methods to the allocation policy
classes, but did not add them to InfallibleAllocPolicy.
I think the idea of these methods is that the callers are explicitly
opting into fallible behavior, so they will deal with any errors that
occur. For instance, in js::HashTable, this is used to try to shrink
the hash table when there are a lot of unused entries. If the shrink
fails, it just continues to use the existing block of memory.
However, having fallible methods in a supposedly infallible class is
weird, so for now, just use the infallible version.
MozReview-Commit-ID: 97D66Z4oLfl
Code that uses InfallibleAllocPolicy presumably wants for operations
to always succeed. However, Vector and HashTable can end up detecting
that growing the data structure will fail due to integer overflow, and
then will call reportAllocOverflow() and fail. I think these cases
should crash.
In addition, pod_malloc and pod_realloc should crash rather than
returning NULL when they detect overflow.
This calls mozalloc_abort rather than MOZ_CRASH directly to avoid
circular #includes, because Assertions.h includes nsTraceRefcnt.h
which includes nscore.h which includes mozalloc.h.
MozReview-Commit-ID: 1g99BXLceQI
Since the introduction of the STL wrappers, they have included
mozalloc.h, and multiple times, we've hit header reentrancy problems,
and worked around them as best as we could.
Taking a step back, all mozalloc.h does is:
- declare moz_* allocator functions.
- define inline implementations of various operator new/delete variants.
The first only requires the functions to be declared before they are used,
so mozalloc.h only needs to be included before anything that would use
those functions.
The second doesn't actually require a specific order, as long as the
declaration for those functions comes before their use, and they are
either declared in <new> or implicitly by the C++ compiler.
So all in all, it doesn't matter that mozalloc.h is included before the
wrapped STL headers. What matters is that it's included when STL headers
are included. So arrange things such that mozalloc.h is included after
the first wrapped STL header is fully preprocessed (and all its includes
have been included).
We need to use _impl variants within mozalloc.h when they are defined because
of how mozglue.dll is linked on Windows, where using malloc/free would use
the symbols from the MSVCRT instead of ours.
If new doesn't throw bad_alloc the compiler emits a null check after to avoid
calling the constructor. http://llvm.org/bugs/show_bug.cgi?id=10895
Adding throw(std::bad_alloc) shaves 57KB of .text off a gcc mac build and 61KB off
a clang build.
Overwrite the OSX default zone allocator, taking into account the malloc_zone_t
version (supported versions are 3, 6, and 8) for Leopard, Snow Leopard and
Lion. jemalloc can be dynamically disabled for unknown malloc_zone_t versions,
for OSX 10.8 and beyond.
The changeset does not enable jemalloc, to allow for easy disabling if there's
a problem. It will be enabled in the next changeset.
This should be a 15-20% improvement in memory usage.
