Summary:
This is for coding standard conformance, and for fixing an ODR violation
issue: __xray::ThreadLocalData is defined twice and differently in
xray_fdr_logging.cc and xray_basic_logging.cc
Reviewers: dberris, mboerger, eizan
Reviewed By: dberris
Subscribers: delcypher, jfb, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D52639
llvm-svn: 343289
Summary:
This change allows us to use the library path from which the LLVM
libraries are installed, in case the LLVM installation generates shared
libraries.
This should address llvm.org/PR39070.
Reviewers: mboerger, eizan
Subscribers: mgorny, jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D52597
llvm-svn: 343280
Summary:
This change spans both LLVM and compiler-rt, where we do the following:
- Add XRay to the LLVMBuild system, to allow for distributing the XRay
trace loading library along with the LLVM distributions.
- Use `llvm-config` better in the compiler-rt XRay implementation, to
depend on the potentially already-distributed LLVM XRay library.
While this is tested with the standalone compiler-rt build, it does
require that the LLVMXRay library (and LLVMSupport as well) are
available during the build. In case the static libraries are available,
the unit tests will build and work fine. We're still having issues with
attempting to use a shared library version of the LLVMXRay library since
the shared library might not be accessible from the standard shared
library lookup paths.
The larger change here is the inclusion of the LLVMXRay library in the
distribution, which allows for building tools around the XRay traces and
profiles that the XRay runtime already generates.
Reviewers: echristo, beanz
Subscribers: mgorny, hiraditya, mboerger, llvm-commits
Differential Revision: https://reviews.llvm.org/D52349
llvm-svn: 342859
Summary:
The implementation of `internal_mmap(...)` deviates from the contract of
`mmap(...)` -- i.e. error returns are actually the equivalent of `errno`
results. We update how XRay uses `internal_mmap(...)` to better handle
these error conditions.
In the process, we change the default pointers we're using from `char*`
to `uint8_t*` to prevent potential usage of the pointers in the string
library functions that expect to operate on `char*`.
We also take the chance to "promote" sizes of individual `internal_mmap`
requests to at least page size bytes, consistent with the expectations
of calls to `mmap`.
Reviewers: cryptoad, mboerger
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D52361
llvm-svn: 342745
Summary:
This change introduces an `FDRLogWriter` type which is responsible for
serialising metadata and function records to character buffers. This is
the first step in a refactoring of the implementation of the FDR runtime
to allow for more granular testing of the individual components of the
implementation.
The main contribution of this change is a means of hiding the details of
how specific records are written to a buffer, and for managing the
extents of these buffers. We make use of C++ features (templates and
some metaprogramming) to reduce repetition in the act of writing out
specific kinds of records to the buffer.
In this process, we make a number of changes across both LLVM and
compiler-rt to allow us to use the `Trace` abstraction defined in the
LLVM project in the testing of the runtime implementation. This gives us
a closer end-to-end test which version-locks the runtime implementation
with the loading implementation in LLVM.
We also allow using gmock in compiler-rt unit tests, by adding the
requisite definitions in the `AddCompilerRT.cmake` module. We also add
the terminfo library detection along with inclusion of the appropriate
compiler flags for header include lookup.
Finally, we've gone ahead and updated the FDR logging implementation to
use the FDRLogWriter for the lowest-level record-writing details.
Following patches will isolate the state machine transitions which
manage the set-up and tear-down of the buffers we're using in multiple
threads.
Reviewers: mboerger, eizan
Subscribers: mgorny, jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D52220
llvm-svn: 342617
Instead of assuming `-ltinfo` works, check whether there's terminfo
support on the host where LLVMSupport is compiled.
Follow-up to D52220.
llvm-svn: 342523
Summary:
This change introduces an `FDRLogWriter` type which is responsible for
serialising metadata and function records to character buffers. This is
the first step in a refactoring of the implementation of the FDR runtime
to allow for more granular testing of the individual components of the
implementation.
The main contribution of this change is a means of hiding the details of
how specific records are written to a buffer, and for managing the
extents of these buffers. We make use of C++ features (templates and
some metaprogramming) to reduce repetition in the act of writing out
specific kinds of records to the buffer.
In this process, we make a number of changes across both LLVM and
compiler-rt to allow us to use the `Trace` abstraction defined in the
LLVM project in the testing of the runtime implementation. This gives us
a closer end-to-end test which version-locks the runtime implementation
with the loading implementation in LLVM.
We also allow using gmock in compiler-rt unit tests, by adding the
requisite definitions in the `AddCompilerRT.cmake` module.
Finally, we've gone ahead and updated the FDR logging implementation to
use the FDRLogWriter for the lowest-level record-writing details.
Following patches will isolate the state machine transitions which
manage the set-up and tear-down of the buffers we're using in multiple
threads.
Reviewers: mboerger, eizan
Subscribers: mgorny, jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D52220
llvm-svn: 342518
Summary:
This change makes XRay FDR mode use a single backing store for the
buffer queue, and have indexes into that backing store instead. We also
remove the reliance on the internal allocator implementation in the FDR
mode logging implementation.
In the process of making this change we found an inconsistency with the
way we're returning buffers to the queue, and how we're setting the
extents. We take the chance to simplify the way we're managing the
extents of each buffer. It turns out we do not need the indirection for
the extents, so we co-host the atomic 64-bit int with the buffer object.
It also seems that we've not been returning the buffers for the thread
running the flush functionality when writing out the files, so we can
run into a situation where we could be missing data.
We consolidate all the allocation routines now into xray_allocator.h,
where we used to have routines defined in xray_buffer_queue.cc.
Reviewers: mboerger, eizan
Subscribers: jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D52077
llvm-svn: 342356
This API has been deprecated three months ago and shouldn't be used
anymore, all clients should migrate to the new string based API.
Differential Revision: https://reviews.llvm.org/D51606
llvm-svn: 342318
Summary:
This change has a number of fixes for FDR mode in compiler-rt along with
changes to the tooling handling the traces in llvm.
In the runtime, we do the following:
- Advance the "last record" pointer appropriately when writing the
custom event data in the log.
- Add XRAY_NEVER_INSTRUMENT in the rewinding routine.
- When collecting the argument of functions appropriately marked, we
should not attempt to rewind them (and reset the counts of functions
that can be re-wound).
In the tooling, we do the following:
- Remove the state logic in BlockIndexer and instead rely on the
presence/absence of records to indicate blocks.
- Move the verifier into a loop associated with each block.
Reviewers: mboerger, eizan
Subscribers: llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D51965
llvm-svn: 342122
Summary:
In this change we apply `XRAY_NEVER_INSTRUMENT` to more functions in the
profiling implementation to ensure that these never get instrumented if
the compiler used to build the library is capable of doing XRay
instrumentation.
We also consolidate all the allocators into a single header
(xray_allocator.h) which sidestep the use of the internal allocator
implementation in sanitizer_common.
This addresses more cases mentioned in llvm.org/PR38577.
Reviewers: mboerger, eizan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D51776
llvm-svn: 341647
using sysctl to get the tic frequency data.
still linkage issue for X-ray_init not resolved.
Reviewers: dberris, kubamracek
Reviewed By: dberris
Differential Revision: https://reviews.llvm.org/D51399
llvm-svn: 341019
Summary:
This change removes further cases where the profiling mode
implementation relied on dynamic memory allocation. We're using
thread-local aligned (uninitialized) memory instead, which we initialize
appropriately with placement new.
Addresses llvm.org/PR38577.
Reviewers: eizan, kpw
Subscribers: jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D51278
llvm-svn: 340814
Summary:
This change saves and restores the full flags register in x86_64 mode.
This makes running instrumented signal handlers safer, and avoids flags
set during the execution of the event handlers from polluting the
instrumented call's flags state.
Reviewers: kpw, eizan, jfb
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D51277
llvm-svn: 340812
Summary:
We avoid using dynamic memory allocated with the internal allocator in
the profile collection service used by profiling mode. We use aligned
storage for globals and in-struct storage of objects we dynamically
initialize.
We also remove the dependency on `Vector<...>` which also internally
uses the dynamic allocator in sanitizer_common (InternalAlloc) in favour
of the XRay allocator and segmented array implementation.
This change addresses llvm.org/PR38577.
Reviewers: eizan
Reviewed By: eizan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D50782
llvm-svn: 339978
Summary:
This reverses an earlier decision to allow seg-faulting from the
XRay-allocated memory if it turns out that the system cannot provide
physical memory backing that cannot be swapped in/out on Linux.
This addresses http://llvm.org/PR38588.
Reviewers: eizan
Reviewed By: eizan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D50831
llvm-svn: 339869
Summary:
This change provides access to the file header even in the in-memory
buffer processing. This allows in-memory processing of the buffers to
also check the version, and the format, of the profile data.
Reviewers: eizan, kpw
Reviewed By: eizan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D50037
llvm-svn: 338347
Summary:
This change moves FDR mode to use `internal_mmap(...)` from
sanitizer_common instead of the internal allocator interface. We're
doing this to sidestep the alignment issues we encounter with the
`InternalAlloc(...)` functions returning pointers that have some magic
bytes at the beginning.
XRay copies bytes into the buffer memory, and does not require the magic
bytes tracking the other sanitizers use when allocating/deallocating
buffers.
Reviewers: kpw, eizan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D49972
llvm-svn: 338228
This change makes it so that the profiling mode implementation will only
write files when there are buffers to write. Before this change, we'd
always open a file even if there were no profiles collected when
flushing.
llvm-svn: 337443
When providing raw access to the FDR mode buffers, we used to not
include the extents metadata record. This oversight means that
processing the buffers in-memory will lose important information that
would have been written in files.
This change exposes the metadata record by serializing the data
similarly to how we would do it when flushing to files.
llvm-svn: 337441
MAP_NORESERVE is not supported or a no-op on BSD.
Reviewers: dberris
Reviewed By: dberris
Differential Revision: https://reviews.llvm.org/D49494
llvm-svn: 337440
Summary:
This is a follow-on to D49217 which simplifies and optimises the
implementation of the segmented array. In this patch we co-locate the
book-keeping for segments in the `__xray::Array<T>` with the data it's
managing. We take the chance in this patch to actually rename `Chunk` to
`Segment` to better align with the high-level description of the
segmented array.
With measurements using benchmarks landed in D48879, we've identified
that calls to `pthread_getspecific` started dominating the cycles, which
led us to revert the change made in D49217 to use C++ thread_local
initialisation instead (it reduces the cost by a huge margin, since we
save one PLT-based call to pthread functions in the hot path). In
particular, this is in `__xray::getThreadLocalData()`.
We also took the opportunity to remove the least-common-multiple based
calculation and instead pack as much data into segments of the array.
This greatly simplifies the API of the container which hides as much of
the implementation details as possible. For instance, we calculate the
number of elements we need for the each segment internally in the Array
instead of making it part of the type.
With the changes here, we're able to get a measurable improvement on the
performance of profiling mode on top of what D48879 already provides.
Depends on D48879.
Reviewers: kpw, eizan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D49363
llvm-svn: 337343
Summary:
This change simplifies the XRay Allocator implementation to self-manage
an mmap'ed memory segment instead of using the internal allocator
implementation in sanitizer_common.
We've found through benchmarks and profiling these benchmarks in D48879
that using the internal allocator in sanitizer_common introduces a
bottleneck on allocating memory through a central spinlock. This change
allows thread-local allocators to eliminate contention on the
centralized allocator.
To get the most benefit from this approach, we also use a managed
allocator for the chunk elements used by the segmented array
implementation. This gives us the chance to amortize the cost of
allocating memory when creating these internal segmented array data
structures.
We also took the opportunity to remove the preallocation argument from
the allocator API, simplifying the usage of the allocator throughout the
profiling implementation.
In this change we also tweak some of the flag values to reduce the
amount of maximum memory we use/need for each thread, when requesting
memory through mmap.
Depends on D48956.
Reviewers: kpw, eizan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D49217
llvm-svn: 337342
Summary:
Fix a bug in FDR mode which didn't allow for re-initialising the logging
in the same process. This change ensures that:
- When we flush the FDR mode logging, that the state of the logging
implementation is `XRAY_LOG_UNINITIALIZED`.
- Fix up the thread-local initialisation to use aligned storage and
`pthread_getspecific` as well as `pthread_setspecific` for the
thread-specific data.
- Actually use the pointer provided to the thread-exit cleanup handling,
instead of assuming that the thread has thread-local data associated
with it, and reaching at thread-exit time.
In this change we also have an explicit test for two consecutive
sessions for FDR mode tracing, and ensuring both sessions succeed.
Reviewers: kpw, eizan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D49359
llvm-svn: 337341
We no longer pass CLANG_DEFAULT_CXX_STDLIB to the runtimes build
as it was causing issues so we can no longer use this variable. We
instead use cxx-headers as a dependency whenever this is available
since both XRay and libFuzzer are built as static libraries so this
is sufficient.
Differential Revision: https://reviews.llvm.org/D49346
llvm-svn: 337199
Summary:
Fix a TODO in CMake config for XRay tests to use the detected C++ ABI
library in the tests.
Also make the tests depend on the llvm-xray target when built in-tree.
Reviewers: kpw, eizan
Reviewed By: eizan
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D49358
llvm-svn: 337142
Summary:
llvm-xray changes:
- account-mode - process-id {...} shows after thread-id
- convert-mode - process {...} shows after thread
- parses FDR and basic mode pid entries
- Checks version number for FDR log parsing.
Basic logging changes:
- Update header version from 2 -> 3
FDR logging changes:
- Update header version from 2 -> 3
- in writeBufferPreamble, there is an additional PID Metadata record (after thread id record and tsc record)
Test cases changes:
- fdr-mode.cc, fdr-single-thread.cc, fdr-thread-order.cc modified to catch process id output in the log.
Reviewers: dberris
Reviewed By: dberris
Subscribers: hiraditya, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D49153
llvm-svn: 336974
Summary:
This change adds support for writing out profiles at program exit.
Depends on D48653.
Reviewers: kpw, eizan
Reviewed By: kpw
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D48956
llvm-svn: 336969
The list duplicates information already available in the parent
directory so use that instead. It is unclear to me why we need
to spell out the dependencies explicitly but fixing that should
be done in a separate patch.
Differential Revision: https://reviews.llvm.org/D49177
llvm-svn: 336905
Summary: XRayRecords now includes a PID field. Basic handlers fetch pid and tid each time they are called instead of caching the value. Added a testcase that calls fork and checks if the child TID is different from the parent TID to verify that the processes' TID are different in the trace.
Reviewers: dberris, Maknee
Reviewed By: dberris, Maknee
Subscribers: kpw, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D49025
llvm-svn: 336769
It turns out that the `${XRAY_HEADERS}` CMake variable was already
in use and was used for public headers. It seems that
`lib/xray/tests/CMakeLists.txt` was depending on this.
To fix rename the new `${XRAY_HEADERS}` to `${XRAY_IMPL_HEADERS}`.
llvm-svn: 336699
when building with an IDE so that header files show up in the UI.
This massively improves the development workflow in IDEs.
To implement this a new function `compiler_rt_process_sources(...)` has
been added that adds header files to the list of sources when the
generator is an IDE. For non-IDE generators (e.g. Ninja/Makefile) no
changes are made to the list of source files.
The function can be passed a list of headers via the
`ADDITIONAL_HEADERS` argument. For each runtime library a list of
explicit header files has been added and passed via
`ADDITIONAL_HEADERS`. For `tsan` and `sanitizer_common` a list of
headers was already present but it was stale and has been updated
to reflect the current state of the source tree.
The original version of this patch used file globbing (`*.{h,inc,def}`)
to find the headers but the approach was changed due to this being a
CMake anti-pattern (if the list of headers changes CMake won't
automatically re-generate if globbing is used).
The LLVM repo contains a similar function named `llvm_process_sources()`
but we don't use it here for several reasons:
* It depends on the `LLVM_ENABLE_OPTION` cache variable which is
not set in standalone compiler-rt builds.
* We would have to `include(LLVMProcessSources)` which I'd like to
avoid because it would include a bunch of stuff we don't need.
Differential Revision: https://reviews.llvm.org/D48422
llvm-svn: 336663
Changes:
- Remove static assertion on size of a structure, fails on systems where
pointers aren't 8 bytes.
- Use size_t instead of deducing type of arguments to
`nearest_boundary`.
Follow-up to D48653.
llvm-svn: 336648
Summary:
We found a bug while working on a benchmark for the profiling mode which
manifests as a segmentation fault in the profiling handler's
implementation. This change adds unit tests which replicate the
issues in isolation.
We've tracked this down as a bug in the implementation of the Freelist
in the `xray::Array` type. This happens when we trim the array by a
number of elements, where we've been incorrectly assigning pointers for
the links in the freelist of chunk nodes. We've taken the chance to add
more debug-only assertions to the code path and allow us to verify these
assumptions in debug builds.
In the process, we also took the opportunity to use iterators to
implement both `front()` and `back()` which exposes a bug in the
iterator decrement operation. In particular, when we decrement past a
chunk size boundary, we end up moving too far back and reaching the
`SentinelChunk` prematurely.
This change unblocks us to allow for contributing the non-crashing
version of the benchmarks in the test-suite as well.
Reviewers: kpw
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D48653
llvm-svn: 336644
Summary:
Without this patch,
clang -fsanitize=address -xc =(printf 'int main(){}') -o a; ./a => deadlock in __asan_init>AsanInitInternal>AsanTSDInit>...>__getcontextx_size>_rtld_bind>rlock_acquire(rtld_bind_lock, &lockstate)
libexec/rtld-elf/rtld.c
wlock_acquire(rtld_bind_lock, &lockstate);
if (obj_main->crt_no_init)
preinit_main(); // unresolved PLT functions cannot be called here
lib/libthr/thread/thr_rtld.c
uc_len = __getcontextx_size(); // unresolved PLT function in libthr.so.3
check-xray tests currently rely on .preinit_array so we special case in
xray_init.cc
Subscribers: srhines, kubamracek, krytarowski, delcypher, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D48806
llvm-svn: 336067
When XRay is being built as part of the just built compiler together
with libc++ as part of the runtimes build, we need an explicit
dependency from XRay to libc++ to make sure that the library is
available by the time we start building XRay.
Differential Revision: https://reviews.llvm.org/D48113
llvm-svn: 334575
Summary:
This is part of the larger XRay Profiling Mode effort.
This patch implements the profile writing mechanism, to allow profiles
collected through the profiler mode to be persisted to files.
Follow-on patches would allow us to load these profiles and start
converting/analysing them through the `llvm-xray` tool.
Depends on D44620.
Reviewers: echristo, kpw, pelikan
Reviewed By: kpw
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D45998
llvm-svn: 334472
Summary:
This is part of the larger XRay Profiling Mode effort.
This patch implements the wiring required to enable us to actually
select the `xray-profiling` mode, and install the handlers to start
measuring the time and frequency of the function calls in call stacks.
The current way to get the profile information is by working with the
XRay API to `__xray_process_buffers(...)`.
In subsequent changes we'll implement profile saving to files, similar
to how the FDR and basic modes operate, as well as means for converting
this format into those that can be loaded/visualised as flame graphs. We
will also be extending the accounting tool in LLVM to support
stack-based function call accounting.
We also continue with the implementation to support building small
histograms of latencies for the `FunctionCallTrie::Node` type, to allow
us to actually approximate the distribution of latencies per function.
Depends on D45758 and D46998.
Reviewers: eizan, kpw, pelikan
Reviewed By: kpw
Subscribers: llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D44620
llvm-svn: 334469
