Accessing the PLT entries of hooks can lead a certain amount of
performance overhead. This is observed on certain tasks which will do a
bunch of malloc/free and their throughputs are impacted by the null
check of hooks.
Also add SCUDO_ENABLE_HOOKS_TESTS to select if we want to run the hook
tests. On some platforms they may have different ways to run the
wrappers tests (end-to-end tests) and test the hooks along with the
wrappers tests may not be feasible. Provide an option to turn it ON/OFF.
By default, we only verify the hook behavior in the scudo standalone
tests if SCUDO_ENABLE_HOOKS is defined or COMPILER_RT_DEBUG is true.
Reviewed By: cferris, fabio-d
Differential Revision: https://reviews.llvm.org/D158784
Move the invocation of hooks from Scudo internal to wrapper_c.cpp and
wrapper_c_bionic.cpp respectively. Therefore, Scudo's core algorithm
doesnt need to worry about the reentrant of hooks and leave the caring
of reentrant to the hook users.
Reviewed By: hctim, cferris, chelfi
Differential Revision: https://reviews.llvm.org/D152188
This lets us remove two pointer indirections (one by removing the pointer,
and another by making the AllocatorPtr declaration hidden) in the C++ wrappers.
Differential Revision: https://reviews.llvm.org/D74356
Summary:
fork() wasn't well (or at all) supported in Scudo. This materialized
in deadlocks in children.
In order to properly support fork, we will lock the allocator pre-fork
and unlock it post-fork in parent and child. This is done via a
`pthread_atfork` call installing the necessary handlers.
A couple of things suck here: this function allocates - so this has to
be done post initialization as our init path is not reentrance, and it
doesn't allow for an extra pointer - so we can't pass the allocator we
are currently working with.
In order to work around this, I added a post-init template parameter
that gets executed once the allocator is initialized for the current
thread. Its job for the C wrappers is to install the atfork handlers.
I reorganized a bit the impacted area and added some tests, courtesy
of cferris@ that were deadlocking prior to this fix.
Subscribers: jfb, #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D72470
