Summary:
This change completes the refactoring of the FDR runtime to support the
following:
- Generational buffer management.
- Centralised and well-tested controller implementation.
In this change we've had to:
- Greatly simplify the code in xray_fdr_logging.cc to only implement the
glue code for calling into the controller.
- Implement the custom and typed event logging functions in the
FDRLogWriter.
- Imbue the `XRAY_NEVER_INSTRUMENT` attribute onto all functions in the
controller implementation.
Reviewers: mboerger, eizan, jfb
Subscribers: jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D53858
llvm-svn: 345568
Summary:
Some cases where `postCurrentThreadFCT()` are not guarded by our
recursion guard. We've observed that sometimes these can lead to
deadlocks when some functions (like memcpy()) gets outlined and the
version of memcpy is XRay-instrumented, which can be materialised by the
compiler in the implementation of lower-level components used by the
profiling runtime.
This change ensures that all calls to `postCurrentThreadFCT` are guarded
by our thread-recursion guard, to prevent deadlocks.
Reviewers: mboerger, eizan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D53805
llvm-svn: 345489
Summary:
In D53560, we assumed a specific layout for memory without using an
explicit structure. This follow-up change uses more portable layout
control by using unions in a struct, and consolidating the memory
management code in the buffer queue.
We also take the opportunity to improve the documentation on the types
and operations, along with simplifying some of the logic in the buffer
queue implementation.
Reviewers: mboerger, eizan
Subscribers: jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D53802
llvm-svn: 345485
Summary:
This change implements the ref-counting for backing stores associated
with generational buffer management. We do this as an implementation
detail of the buffer queue, instead of exposing this to the interface.
This change allows us to keep the buffer queue interface and usage model
the same.
Depends on D53551.
Reviewers: mboerger, eizan
Subscribers: jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D53560
llvm-svn: 345471
Summary:
This is an intermediary step in the full support for generational buffer
management in the FDR runtime. This change makes the FDR controller
aware of the new generation number in the buffers handed out by the
BufferQueue type.
In the process of making this change, we've realised that the cleanest
way of ensuring that the backing store per generation is live while all
the threads that need access to it will need reference counting to tie
the backing store to the lifetime of all threads that have a handle on
buffers associated with the memory.
We also learn that we're missing the edge-case in the function exit
handler's implementation where the first record being written into the
buffer is a function exit, which is caught/fixed by the test for
generational buffer management.
We still haven't wired the controller into the FDR mode runtime, which
will need the reference counting on the backing store implemented to
ensure that we're being conservatively thread-safe with this approach.
Depends on D52974.
Reviewers: mboerger, eizan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D53551
llvm-svn: 345445
Change the assumption when releasing memory to a buffer queue that new
generations might not be able to re-use the memory mapped addresses.
llvm-svn: 344882
Summary:
This change updates the buffer queue implementation to support using a
generation number to identify the lifetime of buffers. This first part
introduces the notion of the generation number, without changing the way
we handle the buffers yet.
What's missing here is the cleanup of the buffers. Ideally we'll keep
the two most recent generations. We need to ensure that before we do any
writes to the buffers, that we check the generation number(s) first.
Those changes will follow-on from this change.
Depends on D52588.
Reviewers: mboerger, eizan
Subscribers: llvm-commits, jfb
Differential Revision: https://reviews.llvm.org/D52974
llvm-svn: 344881
Summary:
This change allows us to handle allocator exhaustion properly in the
segmented array implementation. Before this change, we relied on the
caller of the `trim` function to provide a valid number of elements to
trim. This change allows us to do the right thing in case the elements
to trim is greater than the size of the container.
Reviewers: mboerger, eizan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D53484
llvm-svn: 344880
Summary:
This change updates the buffer queue implementation to support using a
generation number to identify the lifetime of buffers. This first part
introduces the notion of the generation number, without changing the way
we handle the buffers yet.
What's missing here is the cleanup of the buffers. Ideally we'll keep
the two most recent generations. We need to ensure that before we do any
writes to the buffers, that we check the generation number(s) first.
Those changes will follow-on from this change.
Depends on D52588.
Reviewers: mboerger, eizan
Subscribers: llvm-commits, jfb
Differential Revision: https://reviews.llvm.org/D52974
llvm-svn: 344670
This abstracts away the file descriptor related logic which makes it
easier to port XRay to platform that don't use file descriptors or
file system for writing the log data, such as Fuchsia.
Differential Revision: https://reviews.llvm.org/D52161
llvm-svn: 344578
Summary:
This change implements a controller for abstracting away the details of
what happens when tracing with FDR mode. This controller type allows us
to test in isolation the various cases where we're encountering function
entry, exit, and other kinds of events we are handling when FDR mode is
enabled.
This change introduces a number of testing facilities we've needed to
better support expressing the conditions we need for the unit tests. We
leave some TODOs for moving those utilities into the LLVM project,
sitting in the `Testing` library, to make matching conditions on XRay
`Trace` instances through googlemock more manageable and declarative.
We don't wire in the controller right away, to allow us to incrementally
update the implementation(s) as we increase testing coverage of the
controller type. There's a need to re-think the way we're managing
buffers in a multi-threaded environment, which is more invasive than
this implementation.
This step in the process allows us to encode our assumptions in the
implementation of the controller, and then evolve the buffer queue
implementation to support generational buffer management to ensure we
can continue to support the cases we're already supporting with the
controller.
Reviewers: mboerger, eizan
Subscribers: mgorny, llvm-commits, jfb
Differential Revision: https://reviews.llvm.org/D52588
llvm-svn: 344488
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
This change uses 'const' for the retryingWriteAll(...) API and removes
unnecessary 'static' local variables in getting the temporary filename.
llvm-svn: 334267
Summary:
This fixes http://llvm.org/PR32274.
This change adds a test to ensure that we're able to link XRay modes and
the runtime to binaries that don't need to depend on the C++ standard
library or a C++ ABI library. In particular, we ensure that this will work
with C programs compiled+linked with XRay.
To make the test pass, we need to change a few things in the XRay
runtime implementations to remove the reliance on C++ ABI features. In
particular, we change the thread-safe function-local-static
initialisation to use pthread_* instead of the C++ features that ensure
non-trivial thread-local/function-local-static initialisation.
Depends on D47696.
Reviewers: dblaikie, jfb, kpw, eizan
Reviewed By: kpw
Subscribers: echristo, eizan, kpw, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D46998
llvm-svn: 334262
Summary:
This change extracts the recursion guard implementation from FDR Mode
and updates it to do the following:
- Do the atomic operation correctly to be signal-handler safe.
- Make it usable in both FDR and Basic Modes.
Before this change, the recursion guard relied on an unsynchronised read
and write on a volatile thread-local. A signal handler could then run in
between the read and the write, and then be able to run instrumented
code as part of the signal handling. Using an atomic exchange instead
fixes that by doing a proper mutual exclusion even in the presence of
signal handling.
Reviewers: kpw, eizan, jfb
Reviewed By: eizan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D47696
llvm-svn: 334064
We don't actually need to support multiple definitions of the functions
in FDR mode, but rather want to make sure that the implementation-detail
functions are marked as 'static' instead. This allows the inliner to do
its magic better for these functions too, since inline functions must
have a unique address across translation units.
llvm-svn: 334001
We planned to have FDR mode's internals unit-tested but it turns out
that we can just use end-to-end testing to verify the implementation.
We're going to move towards that approach more and more going forward,
so we're merging the implementation details of FDR mode into a single
.cc file.
We also avoid globbing in the XRay test helper macro, and instead list
down the files from the lib directory.
llvm-svn: 333986
Summary:
This is part of the work to address http://llvm.org/PR32274.
We remove the calls to array-placement-new and array-delete. This allows
us to rely on the internal memory management provided by
sanitizer_common/sanitizer_internal_allocator.h.
Reviewers: eizan, kpw
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D47695
llvm-svn: 333982
XRay doesn't use RTTI and doesn't need it. We disable it explicitly in
the CMake config, similar to how the other sanitizers already do it.
Part of the work to address http://llvm.org/PR32274.
llvm-svn: 333867
Summary:
This is part of the larger XRay Profiling Mode effort.
This patch implements a centralised collector for `FunctionCallTrie`
instances, associated per thread. It maintains a global set of trie
instances which can be retrieved through the XRay API for processing
in-memory buffers (when registered). Future changes will include the
wiring to implement the actual profiling mode implementation.
This central service provides the following functionality:
* Posting a `FunctionCallTrie` associated with a thread, to the central
list of tries.
* Serializing all the posted `FunctionCallTrie` instances into
in-memory buffers.
* Resetting the global state of the serialized buffers and tries.
Depends on D45757.
Reviewers: echristo, pelikan, kpw
Reviewed By: kpw
Subscribers: llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D45758
llvm-svn: 333624
Summary:
This is part of the larger XRay Profiling Mode effort.
This patch implements a central data structure for capturing statistics
about XRay instrumented function call stacks. The `FunctionCallTrie`
type does the following things:
* It keeps track of a shadow function call stack of XRay instrumented
functions as they are entered (function enter event) and as they are
exited (function exit event).
* When a function is entered, the shadow stack contains information
about the entry TSC, and updates the trie (or prefix tree)
representing the current function call stack. If we haven't
encountered this function call before, this creates a unique node for
the function in this position on the stack. We update the list of
callees of the parent function as well to reflect this newly found
path.
* When a function is exited, we compute statistics (TSC deltas,
function call count frequency) for the associated function(s) up the
stack as we unwind to find the matching entry event.
This builds upon the XRay `Allocator` and `Array` types in Part 1 of
this series of patches.
Depends on D45756.
Reviewers: echristo, pelikan, kpw
Reviewed By: kpw
Subscribers: llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D45757
llvm-svn: 332313
Summary:
This change allows for handling the in-memory data associated with the
FDR mode implementation through the new `__xray_log_process_buffers`
API. With this change, we can now allow users to process the data
in-memory of the process instead of through writing files.
This for example allows users to stream the data of the FDR logging
implementation through network sockets, or through other mechanisms
instead of saving them to local files.
We introduce an FDR-specific flag, for "no_file_flush" which lets the
flushing logic skip opening/writing to files.
This option can be defaulted to `true` when building the compiler-rt
XRay runtime through the `XRAY_FDR_OPTIONS` preprocessor macro.
Reviewers: kpw, echristo, pelikan, eizan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D46574
llvm-svn: 332208
This change adds some assembler comments to facilitate analysis with
llvm-mca. In particular, we're interested in identifying and later
optimising (reducing) the cost of the key functions in the XRay
implementation using both static analysis (with llvm-mca, etc.) and
dynamic analysis (perf profiling, etc.) of microbenchmarks.
llvm-svn: 331711
Summary:
This addresses http://llvm.org/PR36790.
This change allows the XRay Basic Mode implementation to use the
string-based initialization routine provided through
`__xray_log_init_mode(...)`. In the process, we've also deprecated some
flags defined for the `XRAY_OPTIONS` environment variable.
We then introduce another environment variable that can control the XRay
Basic Mode implementation through `XRAY_BASIC_OPTIONS`.
We also rename files from `xray_inmemory_log` to `xray_basic_logging` to
be more in line with the mode implementation.
Depends on D46174.
Reviewers: echristo, kpw, pelikan, eizan
Reviewed By: kpw
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D46246
llvm-svn: 331507
Summary:
In this chage we add support for the string-based configuration
mechanism for configuring FDR mode.
We deprecate most of the `xray_fdr_log_*` flags that are set with the
`XRAY_OPTIONS` environment variable. Instead we make the FDR
implementation take defaults from the `XRAY_FDR_OPTIONS` environment
variable, and use the flags defined in `xray_fdr_flags.{h,cc,inc}` for
the options we support.
This change addresses http://llvm.org/PR36790.
Depends on D46173.
Reviewers: eizan, pelikan, kpw, echristo
Subscribers: llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D46174
llvm-svn: 331506
Summary:
This addresses http://llvm.org/PR36790.
The change Deprecates a number of functions and types in
`include/xray/xray_log_interface.h` to recommend using string-based
configuration of XRay through the __xray_log_init_mode(...) function. In
particular, this deprecates the following:
- `__xray_set_log_impl(...)` -- users should instead use the
`__xray_log_register_mode(...)` and `__xray_log_select_mode(...)` APIs.
- `__xray_log_init(...)` -- users should instead use the
`__xray_log_init_mode(...)` function, which also requires using the
`__xray_log_register_mode(...)` and `__xray_log_select_mode(...)`
functionality.
- `__xray::FDRLoggingOptions` -- in following patches, we'll be
migrating the FDR logging implementations (and tests) to use the
string-based configuration. In later stages we'll remove the
`__xray::FDRLoggingOptions` type, and ask users to migrate to using the
string-based configuration mechanism instead.
- `__xray::BasicLoggingOptions` -- same as `__xray::FDRLoggingOptions`,
we'll be removing this type later and instead rely exclusively on the
string-based configuration API.
We also update the documentation to reflect the new advice and remove
some of the deprecated notes.
Reviewers: eizan, kpw, echristo, pelikan
Reviewed By: kpw
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D46173
llvm-svn: 331503
Summary:
This change is part of the larger XRay Profiling Mode effort.
Here we implement an arena allocator, for fixed sized buffers used in a
segmented array implementation. This change adds the segmented array
data structure, which relies on the allocator to provide and maintain
the storage for the segmented array.
Key features of the `Allocator` type:
* It uses cache-aligned blocks, intended to host the actual data. These
blocks are cache-line-size multiples of contiguous bytes.
* The `Allocator` has a maximum memory budget, set at construction
time. This allows us to cap the amount of data each specific
`Allocator` instance is responsible for.
* Upon destruction, the `Allocator` will clean up the storage it's
used, handing it back to the internal allocator used in
sanitizer_common.
Key features of the `Array` type:
* Each segmented array is always backed by an `Allocator`, which is
either user-provided or uses a global allocator.
* When an `Array` grows, it grows by appending a segment that's
fixed-sized. The size of each segment is computed by the number of
elements of type `T` that can fit into cache line multiples.
* An `Array` does not return memory to the `Allocator`, but it can keep
track of the current number of "live" objects it stores.
* When an `Array` is destroyed, it will not return memory to the
`Allocator`. Users should clean up the `Allocator` independently of
the `Array`.
* The `Array` type keeps a freelist of the chunks it's used before, so
that trimming and growing will re-use previously allocated chunks.
These basic data structures are used by the XRay Profiling Mode
implementation to implement efficient and cache-aware storage for data
that's typically read-and-write heavy for tracking latency information.
We're relying on the cache line characteristics of the architecture to
provide us good data isolation and cache friendliness, when we're
performing operations like searching for elements and/or updating data
hosted in these cache lines.
Reviewers: echristo, pelikan, kpw
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D45756
llvm-svn: 331141
This code is ill-formed, but under -fno-exceptions compilers generally accept it (at least, prior to C++17). This allows this code to be built by Clang in C++17 mode.
llvm-svn: 330765
Summary:
Typed event patching is implemented for x86-64, but functions must
be defined for other arches.
Reviewers: dberris, pelikan
Subscribers: nemanjai, javed.absar, delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D45749
llvm-svn: 330231
Summary:
Compiler-rt support first before defining the __xray_typedevent() lowering in
llvm. I'm looking for some early feedback before I touch much more code.
Reviewers: dberris
Subscribers: delcypher, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D43668
llvm-svn: 330218
Summary:
- last change (+ the Apple support change) missed a lot of indentation
- shorten architecture SOURCES definitions as most fit 1 line/arch
- comment in English what's where, and where the different .a come from
(using only the word "runtime" in the comment isn't useful, since the
CMake primitive itself says "runtime" in its name)
- skip unsupported architectures quickly, to avoid extra indentation
Reviewers: dberris, eizan, kpw
Subscribers: mgorny, delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D45568
llvm-svn: 329998
Summary:
This patch implements the `-fxray-modes=` flag which allows users
building with XRay instrumentation to decide which modes to pre-package
into the binary being linked. The default is the status quo, which will
link all the available modes.
For this to work we're also breaking apart the mode implementations
(xray-fdr and xray-basic) from the main xray runtime. This gives more
granular control of which modes are pre-packaged, and picked from
clang's invocation.
This fixes llvm.org/PR37066.
Note that in the future, we may change the default for clang to only
contain the profiling implementation under development in D44620, when
that implementation is ready.
Reviewers: echristo, eizan, chandlerc
Reviewed By: echristo
Subscribers: mgorny, mgrang, cfe-commits, llvm-commits
Differential Revision: https://reviews.llvm.org/D45474
llvm-svn: 329772
Summary:
This is D45125; the patch enables the build of XRay on OpenBSD. We also
introduce some OpenBSD specific changes to the runtime implementation,
involving how we get the TSC rate through the syscall interface specific
to OpenBSD.
Reviewers: dberris
Authored by: devnexen
Subscribers: dberris, mgorny, krytarowski, llvm-commits
Differential Revision: https://reviews.llvm.org/D45125
llvm-svn: 329189
Summary:
This change adds APIs to allow logging implementations to provide a
function for iterating through in-memory buffers (if they hold in-memory
buffers) and a way for users to generically deal with these buffers
in-process. These APIs are:
- __xray_log_set_buffer_iterator(...) and
__xray_log_remove_buffer_iterator(): installs and removes an
iterator function that takes an XRayBuffer and yields the next one.
- __xray_log_process_buffers(...): takes a function pointer that can
take a mode identifier (string) and an XRayBuffer to process this
data as they see fit.
The intent is to have the FDR mode implementation's buffers be
available through this `__xray_log_process_buffers(...)` API, so that
they can be streamed from memory instead of flushed to disk (useful for
getting the data to a network, or doing in-process analysis).
Basic mode logging will not support this mechanism as it's designed to
write the data mostly to disk.
Future implementations will may depend on this API as well, to allow for
programmatically working through the XRay buffers exposed to the
users in some fashion.
Reviewers: eizan, kpw, pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D43495
llvm-svn: 326866
Summary:
This change makes changes to XRay implementation files trigger re-builds
of the unit tests. Prior to this change, the unit tests were not built
and run properly if the implementation files were changed during the
development process. This change forces the dependency on all files in
the XRay include and lib hosted files in compiler-rt.
Caveat is, that new files added to the director(ies) will need a re-run
of CMake to re-generate the fileset.
We think this is an OK compromise, since adding new files may
necessitate editing (or adding) new unit tests. It's also less likely
that we're adding new files without updating the CMake configuration to
include the functionality in the XRay runtime implementation anyway.
Reviewers: pelikan, kpw, nglevin
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D44080
llvm-svn: 326842
Dean Michael Berris