For compiling things automake never needs to be given a full set of
headers. Usually headers are specified so that make dist includes them
into archive, but we can achieve this goal easier.
This reduces size and complexity of our Makefile.am stuff.
Logic was removed from thread_cache.{h,cc} into
thread_cache_ptr.{h,cc}.
Separation will help possible future evolution, and we already changed
the logic quite a bit:
* early access (when TLS isn't initialized yet) now uses global
ThreadCache instance. We therefore have ThreadCachePtr instances
managing required locking. This eliminates unnecessary complication of
PTHREADS_CRASHES_IF_RUN_TOO_EARLY logic, and any other danger of
touching TLS too early. BTW previous implementation actually leaked
initial early-initialized ThreadCache instance(!)
* old configure-time HAVE_TLS logic is amputated. Config-time part of
it made little sense as C++ 17 guarantees availability of
thread_local, but we have manually curated deny-list of "bad" OSes,
that we tested (via compile checks!) at configure time. Now this
is all compile time. There is now compile-time kHaveGoodTLS variable
and we're using it mostly via if constexpr.
* kHaveGoodTLS case of creating thread cache is simplified and made
more straightforward (no need to have in_setspecific logic).
* !kHaveGoodTLS case if fixed and improved too. We avoid
std:🧵:get_id, as it deadlocks on mingw. We use errno address as
a portable and (usually) async-signal safe 'my thread' identifier. We
also eliminate linear searching of thread's cache and replace it with
straightforward hash table lookup.
This allows us, later, to avoid building this stuff in configurations
that don't use it. I have also reduced API and ABI surface to enable
further refactorings.
* Remove build dependency on HAVE_PTHREAD
* Remove build dependency on HAVE_STD_ALIGNED_VAL_T and ENABLE_ALIGNED_NEW_DELETE
* Remove redundant tcmalloc.h files & ensure there are no cross-build-tool references
* Adopt automake commit 26927d1 in the CMake build
- Fix CMake builds for MinGW and MSVC
- Ensure the Autotools, CMake and VSProj builds do not reference each others' config.h
- Use std:🧵:id instead of our own thread ID wrappers
- Moved explicit TLS wrapper functions into the tcmalloc:: namespace and change their visibility to hidden
Resolves#1486
See github issue #1474 for immediate reason.
Note, this entire idea of number of convenience libraries is likely
simply artifact of Google's codebase past. We don't really need this
complexity. But I am holding big reorganization of this for after API
and ABI work. For now, simply moving dynamic_annotations.cc into
libsysinfo fixes things. Most of the code links both anyways. So lets
just do it.
We do shell wrapper for actual test run, so we can inspect output of
pprof. But when we set up sampling_debug_test.sh we simply copied
regular sampling_test.sh, which ran same non-debug test binary. Now we
sed-replace contents of shell program when copying, so we test right
binary.
Another thing we fix here is our (still hardcoded) test output path is
now different between sampling{,_debug}_test.sh. So this fixes main
cause of flakiness of our unit tests.
We used msync to verify that address is readable. But msync gives
false positives for PROT_NONE mappings. And we recently got bug report
from user hitting this exact condition.
For correct access check, we steal idea from Abseil and do sigprocmask
with address used as new signal mask and with invalid HOW
argument. This works in today's Linux kernels and is among fastest
methods available. But is brittle w.r.t. possible kernel changes. So
we supply fallback method that does 2 syscalls.
For non-Linux systems we implement usual "write to pipe" trick. Which
also has decent performance, but requires occasional pipe draining and
uses fds which could occasionally be damaged by some forking codes.
We also finally cover all new code with unit test.
Fixes github issue #1426
This unbreaks building on older Linux distros. We missed this at
46d3315ad7 when dropped maybe_thread
stuff, since libprofiler indeed uses pthread, and because on newer
libc-s pthread stuff is now part of regular libc.so.
I am also dropping bogus LIBPROFILER stuff referring to some rpath
badness. Unsure what it was, maybe way back we did libstacktrace as a
proper libtool library, so maybe something was needed. But it is just
a convenience archive this days, so we don't really need to add it
everywhere libprofiler.la is linked.
There was this piece of makefile with indention to add stack tracing
functionality (for stuff like growthz, GetCallerStackTrace and
probably heap sampling) to work even in minimal configuration on
mingw.
What is odd is we fail to actually define libstacktrace.la target on
mingw, since libstacktrace.la requires WITH_STACK_TRACE automake
conditional which we don't enable on this platform. And yet somehow it
doesn't fail. It produces empty libstacktrace.la, so build kinda
works. Except at least on my machine it produces racy makefiles. So
lets not pretend and stop breaking our parallel builds.
Previous implementation wasn't entirely safe w.r.t. 32-bit off_t
systems. Specifically around mmap replacement hook. Also, API was a
lot more general and broad than we actually need.
Sadly, old mmap hooks API was shipped with our public headers. But
thankfully it appears to be unused externally (checked via github
search). So we keep this old API and ABI for the sake of formal API
and ABI compatibility. But this old API is now empty and always
fails (some OS/hardware combinations didn't have functional
implementations of those hooks anyways).
New API is 64-bit clean and only provides us with what we need. Namely
being able to react to virtual address space mapping changes for
logging, heap profiling and heap leak checker. I.e. no pre hooks or
mmap-replacement hooks. We also explicitly not ship this API
externally to give us freedom to change it.
New code is also hopefully tidier and slightly more portable. At least
there are fewer arch-specific ifdef-s.
Another somewhat notable change is, since mmap hook isn't needed in
"minimal" configuration, we now don't override system's
mmap/munmap/etc functions in this configuration. No big deal, but it
reduces risk of damage if we somehow mess those up. I.e. musl's mmap
does few things that our mmap replacement doesn't, such as very fancy
vm_lock thingy. Which doesn't look critical, but is good thing for us
not to interfere with when not necessary.
Fixes issue #1406 and issue #1407. Lets also mention issue #1010 which
is somewhat relevant.
This facility allowed us to build tcmalloc without linking in actual
-lpthread. Via weak symbols we checked at runtime if pthread functions
are available and if not, special single-threaded stubs were used
instead. Not always brining in pthread dependency helped performance
of some programs or libraries which depended at runtime on whether
threads are linked or not. Most notable of those are libstdc++ which
uses non-atomic refcounting on single threaded programs.
But such optional dependency on pthreads caused complications for
nearly no benefit. One trouble was reported in github issue #1110.
This days glibc/libstdc++ combo actually depends on
sys/single_threaded.h facility. So bringing pthread at runtime is
fine. Also modern glibc ships pthread symbols inside libc anyways and
libpthread is empty. I also found that for whatever reason on BSDs and
osx we already pulled in proper pthreads too.
So we loose nothing and we get issue #1110 fixed. And we simplify
everything.
- Some small automake changes. Add libc++ for AIX instead of libstdc++
- Add the interface changes for AIX:User-defined malloc replacement
- Add code to avoid use of pthreads library prior to its initialization
- Some small changes to the unittest case
- Update INSTALL for AIX
[alkondratenko@gmail.com]: lower-case/de-trailing-dot for commit subject line
[alkondratenko@gmail.com]: rebase
[alkondratenko@gmail.com]: amputate unused AM_CONDITIONAL for AIX
[alkondratenko@gmail.com]: explicitly mention libc_override_aix.h in Makefile.am
We used to explicitly link to libstdc++, libm and even libpthread, but
this should be handled by libtool since those are dependencies of
libtcmalloc_minimal. What also helps is we now build everything with
C++ compiler, not C. So libstdc++ or (libc++) dependency doesn't need
to be added at all, even if libtool for some reason fails to handle
it.
This fixes issue #1371
From time to time things file inside tcmalloc guts where calling to
malloc is not safe. Regular strerror does locale bits, so will
occasionally open files/malloc/etc. We avoid this by using our own
"safe" variant that hardcodes names of all POSIX errno constants.
We had plenty of old and mostly no more correct i386 cruft. Now that
generic_fp backtracer covers i386 just fine, we can drop explicit x86
backtracer.
With that we refactored and simplified stacktrace.cc mostly around
picking default implementation, but also adding few more minor
cleanups.
The idea is -momit-leaf-frame-pointer gives us performance pretty much
same as fully omitting frame pointers. And having frame pointers
elsewhere allows us to support cases when user's code is built with
frame pointers. We also pass all tests with
TCMALLOC_STACKTRACE_METHOD=generic_fp (not just libunwind or libgcc).
Previously we allowed test programs to be linked at the same time as
weakening is performed, rewriting the .a archives. So lets be more
explicit. We weaken after all-am (which "runs" everything including
libraries and programs), but before all target.
