Atomic functions are semi-hot in profiles.
The CHECKs verify values passed by compiler
and they never fired, so replace them with DCHECKs.
Reviewed By: vitalybuka, melver
Differential Revision: https://reviews.llvm.org/D107373
Currently we have MemoryAccess function that accepts
"bool kAccessIsWrite, bool kIsAtomic" and 4 wrappers:
MemoryRead/MemoryWrite/MemoryReadAtomic/MemoryWriteAtomic.
Such scheme with bool flags is not particularly scalable/extendable.
Because of that we did not have Read/Write wrappers for UnalignedMemoryAccess,
and "true, false" or "false, true" at call sites is not very readable.
Moreover, the new tsan runtime will introduce more flags
(e.g. move "freed" and "vptr access" to memory acccess flags).
We can't have 16 wrappers and each flag also takes whole
64-bit register for non-inlined calls.
Introduce AccessType enum that contains bit mask of
read/write, atomic/non-atomic, and later free/non-free,
vptr/non-vptr.
Such scheme is more scalable, more readble, more efficient
(don't consume multiple registers for these flags during calls)
and allows to cover unaligned and range variations of memory
access functions as well.
Also switch from size log to just size.
The new tsan runtime won't have the limitation of supporting
only 1/2/4/8 access sizes, so we don't need the logarithms.
Also add an inline thunk that converts the new interface to the old one.
For inlined calls it should not add any overhead because
all flags/size can be computed as compile time.
Reviewed By: vitalybuka, melver
Differential Revision: https://reviews.llvm.org/D107276
Currently we save the creation stack for sync objects always.
But it's not needed to some sync objects, most notably atomics.
We simply don't use atomic creation stack anywhere.
Allow callers to control saving of the creation stack
and don't save it for atomics.
Depends on D107257.
Reviewed By: melver
Differential Revision: https://reviews.llvm.org/D107258
Don't lock the sync object inside of MetaMap methods.
This has several advantages:
- the new interface does not confuse thread-safety analysis
so we can remove a bunch of NO_THREAD_SAFETY_ANALYSIS attributes
- this allows use of scoped lock objects
- this allows more flexibility, e.g. locking some other mutex
between searching and locking the sync object
Also prefix the methods with GetSync to be consistent with GetBlock method.
Also make interface wrappers inlinable, otherwise we either end up with
2 copies of the method, or with an additional call.
Reviewed By: melver
Differential Revision: https://reviews.llvm.org/D107256
Currently __tsan_atomic* functions do FuncEntry/Exit using caller PC
and then use current PC (pointing to __tsan_atomic* itself) during
memory access handling. As the result the top function in reports
involving atomics is __tsan_atomic* and the next frame points to user code.
Remove FuncEntry/Exit in atomic functions and use caller PC
during memory access handling. This removes __tsan_atomic*
from the top of report stacks, so that they point right to user code.
The motivation for this is performance.
Some atomic operations are very hot (mostly loads),
so removing FuncEntry/Exit is beneficial.
This also reduces thread trace consumption (1 event instead of 3).
__tsan_atomic* at the top of the stack is not necessary
and does not add any new information. We already say
"atomic write of size 4", "__tsan_atomic32_store" does not add
anything new.
It also makes reports consistent between atomic and non-atomic
accesses. For normal accesses we say "previous write" and point
to user code; for atomics we say "previous atomic write" and now
also point to user code.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D106966
In preparation for replacing tsan Mutex with sanitizer_common Mutex,
which has thread-safety annotations. Thread safety analysis does not
understand MetaMap::GetAndLock which returns a locked sync object.
Reviewed By: vitalybuka, melver
Differential Revision: https://reviews.llvm.org/D106548
I don't think the stat subsystem was ever used since tsan
development in 2012. But it adds lots of code and this
effectively dead code needs to be updated if the runtime
code changes, which adds maintanance cost for no benefit.
Normal profiler usually gives enough info and that info
is more trustworthy.
Remove the stats subsystem.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D106276
Dmitry Vyukov