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
Summary:
- Enabling the build.
- Using assembly for the cpuid parts.
- Using thr_self FreeBSD call to get the thread id
Patch by: David CARLIER
Reviewers: dberris, rnk, krytarowski
Reviewed By: dberris, krytarowski
Subscribers: emaste, stevecheckoway, nglevin, srhines, kubamracek, dberris, mgorny, krytarowski, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D43278
llvm-svn: 325240
Summary:
Allow for options to be defined at compile time, like is already the case for
other sanitizers, via `SCUDO_DEFAULT_OPTIONS`.
Reviewers: alekseyshl, dberris
Reviewed By: alekseyshl, dberris
Subscribers: kubamracek, delcypher, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D42980
llvm-svn: 324620
Summary:
This change expands the amount of registers stashed by the entry and
`__xray_CustomEvent` trampolines.
We've found that since the `__xray_CustomEvent` trampoline calls can show up in
situations where the scratch registers are being used, and since we don't
typically want to affect the code-gen around the disabled
`__xray_customevent(...)` intrinsic calls, that we need to save and restore the
state of even the scratch registers in the handling of these custom events.
Reviewers: pcc, pelikan, dblaikie, eizan, kpw, echristo, chandlerc
Reviewed By: echristo
Subscribers: chandlerc, echristo, hiraditya, davide, dblaikie, llvm-commits
Differential Revision: https://reviews.llvm.org/D40894
llvm-svn: 323940
Summary:
While there, unify InMemoryRawLog and InMemoryRawLogWithArg's coding style:
- swap libc's memcpy(3) for sanitizer's internal memcpy
- use basic pointer arithmetics to compute offsets from the first record
entry in the pre-allocated buffer, which is always the appropriate type
for the given function
- lose the local variable references as the TLD.* names fit just as well
Reviewers: eizan, kpw, dberris, dblaikie
Subscribers: #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D42289
llvm-svn: 322941
FDRLoggingTest::MultiThreadedCycling uses std::array so we need to
include the right C++ header and not rely on transitive dependencies.
llvm-svn: 321485
Summary:
Before this change, XRay would conservatively patch sections of the code
one sled at a time. Upon testing/profiling, this turns out to take an
inordinate amount of time and cycles. For an instrumented clang binary,
the cycles spent both in the patching/unpatching routine constituted 4%
of the cycles -- this didn't count the time spent in the kernel while
performing the mprotect calls in quick succession.
With this change, we're coalescing the number of calls to mprotect from
being linear to the number of instrumentation points, to now being a
lower constant when patching all the sleds through `__xray_patch()` or
`__xray_unpatch()`. In the case of calling `__xray_patch_function()` or
`__xray_unpatch_function()` we're now doing an mprotect call once for
all the sleds for that function (reduction of at least 2x calls to
mprotect).
Reviewers: kpw, eizan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D41153
llvm-svn: 320664
This change makes XRay print the log file output only when the verbosity
level is higher than 0. It reduces the log spam in the default case when
we want XRay running silently, except when there are actual
fatal/serious errors.
We also update the documentation to show how to get the information
after the change to the default behaviour.
llvm-svn: 320550
r319165 introduced a change to CMakeLists.txt for xray where the set of supported
architectures for XRay was iterated over, tested if they could be targeted then
passed to add_compiler_rt_object_libraries. However all targets were passed,
rather than the architecture that was just tested. For cases such as MIPS, where
mips and mips64 are supported, cmake would then test if mips64 could be targetted
resulting in an attempt to produce multiple identical logical target names, falling
afowl of CMP0002.
Reviewers: dberris
Differential Revision: https://reviews.llvm.org/D40890
llvm-svn: 319893
Summary:
This change implements the basic mode filtering similar to what we do in
FDR mode. The implementation is slightly simpler in basic-mode filtering
because we have less details to remember, but the idea is the same. At a
high level, we do the following to decide when to filter function call
records:
- We maintain a per-thread "shadow stack" which keeps track of the
XRay instrumented functions we've encountered in a thread's
execution.
- We push an entry onto the stack when we enter an XRay instrumented
function, and note the CPU, TSC, and type of entry (whether we have
payload or not when entering).
- When we encounter an exit event, we determine whether the function
being exited is the same function we've entered recently, was
executing in the same CPU, and the delta of the recent TSC and the
recorded TSC at the top of the stack is less than the equivalent
amount of microseconds we're configured to ignore -- then we un-wind
the record offset an appropriate number of times (so we can
overwrite the records later).
We also support limiting the stack depth of the recorded functions,
so that we don't arbitrarily write deep function call stacks.
Reviewers: eizan, pelikan, kpw, dblaikie
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D40828
llvm-svn: 319762
Summary:
This change allows for registration of multiple logging implementations
through a central mechanism in XRay, mapping an implementation to a
"mode". Modes are strings that are used as keys to determine which
implementation to install through a single API. This mechanism allows
users to choose which implementation to install either from the
environment variable 'XRAY_OPTIONS' with the `xray_mode=` flag, or
programmatically using the `__xray_select_mode(...)` function.
Here, we introduce two API functions for the XRay logging:
__xray_log_register_mode(Mode, Impl): Associates an XRayLogImpl to a
string Mode. We can only have one implementation associated with a given
Mode.
__xray_log_select_mode(Mode): Finds the associated Impl for Mode and
installs it as if by calling `__xray_set_log_impl(...)`.
Along with these changes, we also deprecate the xray_naive_log and
xray_fdr_log flags and encourage users to instead use the xray_mode
flag.
Reviewers: kpw, dblaikie, eizan, pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D40703
llvm-svn: 319759
Summary:
In cases where we can't use the .preinit_array section (as in Darwin for
example) we instead use dynamic initialisation. We know that this
alternative approach will race with the initializers of other objects at
global scope, but this is strictly better than nothing.
Reviewers: kubamracek, nglevin
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D40599
llvm-svn: 319366
This renames ASM_TSAN_SYMBOL and ASM_TSAN_SYMBOL_INTERCEPTOR to just ASM_SYMBOL and ASM_SYMBOL_INTERCEPTOR, because they can be useful in more places than just TSan. Also introduce a CMake function to add ASM sources to a target.
Differential Revision: https://reviews.llvm.org/D40143
llvm-svn: 319339
rL319241 was a bit too aggressive removing sources dependencies. This
restores the actual required dependency for armhf.
Follow-up to D39114.
llvm-svn: 319255
This isolates the per-architecture files from the common files
implementing the XRay facilities. Because of the refactoring done in
D39114, we were including the definition of the sources in the archive
twice, causing link-time failures.
Follow-up to D39114.
llvm-svn: 319241
This change is the first in a series of changes to get the XRay runtime
building on macOS. This first allows us to build the minimal parts of
XRay to get us started on supporting macOS development. These include:
- CMake changes to allow targeting x86_64 initially.
- Allowing for building the initialisation routines without
`.preinit_array` support.
- Use __sanitizer::SleepForMillis() to work around the lack of
clock_nanosleep on macOS.
- Deprecate the xray_fdr_log_grace_period_us flag, and introduce
the xray_fdr_log_grace_period_ms flag instead, to use
milliseconds across platforms.
Reviewers: kubamracek
Subscribers: llvm-commits, krytarowski, nglevin, mgorny
Differential Review: https://reviews.llvm.org/D39114
llvm-svn: 319165
Summary:
Before this patch, XRay's basic (naive mode) logging would be
initialised and installed in an adhoc manner. This patch ports the
implementation of the basic (naive mode) logging implementation to use
the common XRay framework.
We also make the following changes to reduce the variance between the
usage model of basic mode from FDR (flight data recorder) mode:
- Allow programmatic control of the size of the buffers dedicated to
per-thread records. This removes some hard-coded constants and turns
them into runtime-controllable flags and through an Options
structure.
- Default the `xray_naive_log` option to false. For now, the only way
to start basic mode is to set the environment variable, or set the
default at build-time compiler options. Because of this change we've
had to update a couple of tests relying on basic mode being always
on.
- Removed the reliance on a non-trivially destructible per-thread
resource manager. We use a similar trick done in D39526 to use
pthread_key_create() and pthread_setspecific() to ensure that the
per-thread cleanup handling is performed at thread-exit time.
We also radically simplify the code structure for basic mode, to move
most of the implementation in the `__xray` namespace.
Reviewers: pelikan, eizan, kpw
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D40164
llvm-svn: 318734
Summary:
Before this change, the FDR mode implementation relied on at thread-exit
handling to return buffers back to the (global) buffer queue. This
introduces issues with the initialisation of the thread_local objects
which, even through the use of pthread_setspecific(...) may eventually
call into an allocation function. Similar to previous changes in this
line, we're finding that there is a huge potential for deadlocks when
initialising these thread-locals when the memory allocation
implementation is also xray-instrumented.
In this change, we limit the call to pthread_setspecific(...) to provide
a non-null value to associate to the key created with
pthread_key_create(...). While this doesn't completely eliminate the
potential for the deadlock(s), it does allow us to still clean up at
thread exit when we need to. The change is that we don't need to do more
work when starting and ending a thread's lifetime. We also have a test
to make sure that we actually can safely recycle the buffers in case we
end up re-using the buffer(s) available from the queue on multiple
thread entry/exits.
This change cuts across both LLVM and compiler-rt to allow us to update
both the XRay runtime implementation as well as the library support for
loading these new versions of the FDR mode logging. Version 2 of the FDR
logging implementation makes the following changes:
* Introduction of a new 'BufferExtents' metadata record that's outside
of the buffer's contents but are written before the actual buffer.
This data is associated to the Buffer handed out by the BufferQueue
rather than a record that occupies bytes in the actual buffer.
* Removal of the "end of buffer" records. This is in-line with the
changes we described above, to allow for optimistic logging without
explicit record writing at thread exit.
The optimistic logging model operates under the following assumptions:
* Threads writing to the buffers will potentially race with the thread
attempting to flush the log. To avoid this situation from occuring,
we make sure that when we've finalized the logging implementation,
that threads will see this finalization state on the next write, and
either choose to not write records the thread would have written or
write the record(s) in two phases -- first write the record(s), then
update the extents metadata.
* We change the buffer queue implementation so that once it's handed
out a buffer to a thread, that we assume that buffer is marked
"used" to be able to capture partial writes. None of this will be
safe to handle if threads are racing to write the extents records
and the reader thread is attempting to flush the log. The optimism
comes from the finalization routine being required to complete
before we attempt to flush the log.
This is a fairly significant semantics change for the FDR
implementation. This is why we've decided to update the version number
for FDR mode logs. The tools, however, still need to be able to support
older versions of the log until we finally deprecate those earlier
versions.
Reviewers: dblaikie, pelikan, kpw
Subscribers: llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D39526
llvm-svn: 318733
Summary:
This change fixes the XRay trampolines aside from the __xray_CustomEvent
trampoline to align the stack to 16-byte boundaries before calling the
handler. Before this change we've not been explicitly aligning the stack
to 16-byte boundaries, which makes it dangerous when calling handlers
that leave the stack in a state that isn't strictly 16-byte aligned
after calling the handlers.
We add a test that makes sure we can handle these cases appropriately
after the changes, and prevents us from regressing the state moving
forward.
Fixes http://llvm.org/PR35294.
Reviewers: pelikan, pcc
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D40004
llvm-svn: 318261
Summary:
This change implements the changes required in both clang and
compiler-rt to allow building XRay-instrumented binaries in Darwin. For
now we limit this to x86_64. We also start building the XRay runtime
library in compiler-rt for osx.
A caveat to this is that we don't have the tests set up and running
yet, which we'll do in a set of follow-on changes.
This patch uses the monorepo layout for the coordinated change across
multiple projects.
Reviewers: kubamracek
Subscribers: mgorny, cfe-commits, llvm-commits
Differential Revision: https://reviews.llvm.org/D39114
llvm-svn: 317875
Summary:
This change removes dependencies on STL types:
- std::aligned_storage -- we're using manually-aligned character
buffers instead for metadata and function records.
- std::tuple -- use a plain old struct instead.
This is an incremental step in removing all STL references from the
compiler-rt implementation of XRay (llvm.org/PR32274).
Reviewers: dblaikie, pelikan, kpw
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D39277
llvm-svn: 316816
Summary:
This change removes the dependency on C++ standard library
types/functions in the implementation of the buffer queue. This is an
incremental step in resolving llvm.org/PR32274.
Reviewers: dblaikie, pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D39175
llvm-svn: 316406
Breaks build:
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux/builds/4677/steps/build%20with%20ninja/logs/stdio
In file included from compiler-rt/lib/xray/xray_fdr_logging.cc:34:
In file included from compiler-rt/lib/xray/xray_fdr_logging_impl.h:36:
In file included from compiler-rt/lib/xray/xray_flags.h:18:
compiler-rt/lib/xray/../sanitizer_common/sanitizer_flag_parser.h:23:7: error: '__sanitizer::FlagHandlerBase' has virtual functions but non-virtual destructor [-Werror,-Wnon-virtual-dtor]
class FlagHandlerBase {
llvm-svn: 316348
Summary:
In FDR Mode, when we set up a new buffer for a thread that's just
overflowed, we must place the CPU identifier with the TSC record as the
first record. This is so that we can reconstruct all the function
entry/exit with deltas rooted on a TSC record for the CPU at the
beginning of the buffer.
Without doing this, the tools are rejecting the log for cases when we've
overflown and have different buffers that don't have the CPU and TSC
records as the first entry in the buffers.
Reviewers: pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D38995
llvm-svn: 315987
Summary:
This change allows the XRay basic (naive) mode logging implementation to
start writing the payload entries through the arg1 logging handler. This
implementation writes out the records that the llvm-xray tool and the
trace reader library will start processing in D38550.
This introduces a new payload record type which logs the data through
the in-memory buffer. It uses the same size/alignment that the normal
XRay record entries use. We use a new record type to indicate these new
entries, so that the trace reader library in LLVM can start reading
these entries.
Depends on D38550.
Reviewers: pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D38551
llvm-svn: 314968
Summary:
This change removes the dependency on using a std::deque<...> for the
storage of the buffers in the buffer queue. We instead implement a
fixed-size circular buffer that's resilient to exhaustion, and preserves
the semantics of the BufferQueue.
We're moving away from using std::deque<...> for two reasons:
- We want to remove dependencies on the STL for data structures.
- We want the data structure we use to not require re-allocation in
the normal course of operation.
The internal implementation of the buffer queue uses heap-allocated
arrays that are initialized once when the BufferQueue is created, and
re-uses slots in the buffer array as buffers are returned in order.
We also change the lock used in the implementation to a spinlock
instead of a blocking mutex. We reason that since the release operations
now take very little time in the critical section, that a spinlock would
be appropriate.
This change is related to D38073.
This change is a re-submit with the following changes:
- Keeping track of the live buffers with a counter independent of the
pointers keeping track of the extents of the circular buffer.
- Additional documentation of what the data members are meant to
represent.
Reviewers: dblaikie, kpw, pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D38119
llvm-svn: 314877
Summary:
When the XRay user calls the API to finish writing the log, the thread
which is calling the API still hasn't finished and therefore won't get
its trace written. Add a test for only the main thread to check this.
Reviewers: dberris
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D38493
llvm-svn: 314875
Summary:
This change removes the dependency on using a std::deque<...> for the
storage of the buffers in the buffer queue. We instead implement a
fixed-size circular buffer that's resilient to exhaustion, and preserves
the semantics of the BufferQueue.
We're moving away from using std::deque<...> for two reasons:
- We want to remove dependencies on the STL for data structures.
- We want the data structure we use to not require re-allocation in
the normal course of operation.
The internal implementation of the buffer queue uses heap-allocated
arrays that are initialized once when the BufferQueue is created, and
re-uses slots in the buffer array as buffers are returned in order.
We also change the lock used in the implementation to a spinlock
instead of a blocking mutex. We reason that since the release operations
now take very little time in the critical section, that a spinlock would
be appropriate.
This change is related to D38073.
Reviewers: dblaikie, kpw, pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D38119
llvm-svn: 314766
Summary:
We avoid using C++11's thread_local keyword on non-trivially
destructible objects because it may introduce deadlocks when the C++
runtime registers destructors calling std::malloc(...). The deadlock may
happen when the allocator implementation is itself XRay instrumented.
To avoid having to call malloc(...) and free(...) in particular, we use
pthread_once, pthread_create_key, and pthread_setspecific to instead
manually register the cleanup implementation we want.
The code this replaces used an RAII type that implements the cleanup
functionality in the destructor, that was then initialized as a
function-local thread_local object. While it works in usual situations,
unfortunately it breaks when using a malloc implementation that itself
is XRay-instrumented.
Reviewers: dblaikie, kpw, pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D38073
llvm-svn: 314764
The function was introduced as a convenience that used to be called in
multiple places. Recent refactorings have removed the need to call this
function in multiple places, so inlined the implementation in the single
place it's defined.
Broken out from D38119.
llvm-svn: 314489
Summary:
Write out records about logged function call first arguments. D32840
implements the reading of this in llvm-xray.
Reviewers: dberris
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D32844
llvm-svn: 314378
Summary:
Remove dependency on std::unique_ptr<...> for the global representing
the installed XRay implementation.
Reviewers: dblaikie, kpw, pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D38121
llvm-svn: 313871
Summary:
This change starts differentiating tail exits from normal exits. We also
increase the version number of the "naive" log to version 2, which will
be the starting version where these records start appearing. In FDR mode
we treat the tail exits as normal exits, and are thus subject to the
same treatment with regard to record unwriting.
Updating the version number is important to signal older builds of the
llvm-xray tool that do not deal with the tail exit records must fail
early (and that users should only use the llvm-xray tool built after
the support for tail exits to get accurate handling of these records).
Depends on D37964.
Reviewers: kpw, pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D37965
llvm-svn: 313515
Summary:
Before this change, the recursion guard for the flight data recorder
(FDR) mode handlers were independent. This change makes it so that when
a handler is already in the process of running and somehow the same or
another handler starts running -- say in a signal handler, while the
XRay handler is executing -- then we can use the same thread-local
recursion guard to stop the second handler from running.
Reviewers: kpw, eizan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D37612
llvm-svn: 312992
Summary:
Before this change we seemed to not be running the unit tests, and therefore we
set out to run them. In the process of making this happen we found a divergence
between the implementation and the tests.
This includes changes to both the CMake files as well as the implementation and
headers of the XRay runtime. We've also updated documentation on the changed
functions.
Reviewers: kpw, eizan
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D37290
llvm-svn: 312202
Summary:
This change hides all the initialization of thread_local variables used
by the XRay FDR mode implementation behind a function call. This makes
initialization of thread-local data to be done lazily, instead of
eagerly when they're done as globals. It also gives us an isolation
mechanism if/when we want to change the TLS implementation from using
the C++ thread_local keyword, for something more ad-hoc (potentialy
using pthread directly) on some platforms or set-ups where we cannot use
the C++ thread_local variables.
Reviewers: kpw, eizan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D37248
llvm-svn: 311997
Summary:
XRay has erroneously been returning the address of the first sled in the
instrumentation map for a function id instead of the (runtime-relocated)
functison address. This causes confusion and issues for applications
where:
- The first sled in the function may not be an entry sled (due to
re-ordering or some other reason).
- The caller attempts to find a symbol associated with the pointer at
runtime, because the sled may not be exactly where the function's
known address is (in case of inlined functions or those that have an
external definition for symbols).
This fixes http://llvm.org/PR34340.
Reviewers: eizan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D37202
llvm-svn: 311871
Summary:
This change introduces versions to the instrumentation map entries we
emit for XRay instrumentaiton points. The status quo for the version is
currently set to 0 (as emitted by the LLVM back-end), and versions will
count up to 255 (unsigned char).
This change is in preparation for supporting the newer version of the
custom event sleds that will be emitted by the LLVM compiler.
While we're here, we take the opportunity to stash more registers and
align the stack properly in the __xray_CustomEvent trampoline.
Reviewers: kpw, pcc, dblaikie
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D36816
llvm-svn: 311524
into a function.
Most CMake configuration under compiler-rt/lib/*/tests have
almost-the-same-but-not-quite functions of the form add_X_[unit]tests
for compiling and running the tests.
Much of the logic is duplicated with minor variations across different
sub-folders.
This can harm productivity for multiple reasons:
For newcomers, resulting CMake files are very large, hard to understand,
and hide the intention of the code.
Changes for enabling certain architectures end up being unnecessarily
large, as they get duplicated across multiple folders.
Adding new sub-projects requires more effort than it should, as a
developer has to again copy-n-paste the configuration, and it's not even
clear from which sub-project it should be copy-n-pasted.
With this change the logic of compile-and-generate-a-set-of-tests is
extracted into a function, which hopefully makes writing and reading
CMake much easier.
Differential Revision: https://reviews.llvm.org/D36116
llvm-svn: 310971
Summary:
Define a build-time configuration option for the XRay runtime to
determine whether the archive will add an entry to the `.preinit_array`
section of the binary. We also allow for initializing the XRay data
structures with an explicit call to __xray_init(). This allows us to
give users the capability to initialize the XRay data structures on
demand.
This can allow us to start porting XRay to platforms where
`.preinit_array` isn't a supported section. It also allows us to limit
the effects of XRay in the initialization sequence for applications that
are sensitive to this kind of interference (i.e. large binaries) or
those that want to package XRay control in libraries.
Future changes should allow us to build two different library archives
for the XRay runtime, and allow clang users to determine which version
to link.
Reviewers: dblaikie, kpw, pelikan
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D36080
llvm-svn: 309909
Summary:
This change attempts to remove all the dependencies we have on
std::mutex and any std::shared_ptr construction in global variables. We
instead use raw pointers to these objects, and construct them on the
heap. In cases where it's possible, we lazily initialize these pointers.
While we do not have a replacement for std::shared_ptr yet in
compiler-rt, we use this work-around to avoid having to statically
initialize the objects as globals. Subsequent changes should allow us to
completely remove our dependency on std::shared_ptr and instead have our
own implementation of the std::shared_ptr and std::weak_ptr semantics
(or completely rewrite the implementaton to not need these
standard-library provided abstractions).
Reviewers: dblaikie, kpw, pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D36078
llvm-svn: 309792
Summary:
Currently when the XRay runtime is linked into a binary that doesn't
have the instrumentation map, we print a warning unconditionally. This
change attempts to make this behaviour more quiet.
Reviewers: kpw, pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D35789
llvm-svn: 309534
Currently there's a large amount of CMake logic duplication for
compiling sanitizer tests.
If we add more sanitizers, the duplication will get even worse.
This change factors out common compilation commands into a macro
available to all sanitizers.
llvm-svn: 309405
Summary:
This change introduces two files that show exaples of the
always/never instrument files that can be provided to clang. We don't
add these as defaults yet in clang, which we can do later on (in a
separate change).
We also add a test that makes sure that these apply in the compiler-rt
project tests, and that changes in clang don't break the expectations in
compiler-rt.
Reviewers: pelikan, kpw
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D34669
llvm-svn: 306502
Summary:
This change implements support for the custom event logging sleds and
intrinsics at runtime. For now it only supports handling the sleds in
x86_64, with the implementations for other architectures stubbed out to
do nothing.
NOTE: Work in progress, uploaded for exposition/exploration purposes.
Depends on D27503, D30018, and D33032.
Reviewers: echristo, javed.absar, timshen
Subscribers: mehdi_amini, nemanjai, llvm-commits
Differential Revision: https://reviews.llvm.org/D30630
llvm-svn: 302857
Summary:
This bug is caused by the incorrect handling of return-value registers.
According to OpenPOWER 64-Bit ELF V2 ABI 2.2.5, up to 2 general-purpose
registers are going to be used for return values, and up to 8 floating
point registers or vector registers are going to be used for return
values.
Reviewers: dberris, echristo
Subscribers: nemanjai, llvm-commits
Differential Revision: https://reviews.llvm.org/D33027
llvm-svn: 302691
Summary:
This change allows us to provide users and implementers of XRay handlers
a means of converting XRay function id's to addresses. This, in
combination with the facilities provided in D32695, allows users to find
out:
- How many function id's there are defined in the current binary.
- Get the address of the function associated with this function id.
- Patch only specific functions according to their requirements.
While we don't directly provide symbolization support in XRay, having
the function's address lets users determine this information easily
either during runtime, or offline with tools like 'addr2line'.
Reviewers: dblaikie, echristo, pelikan
Subscribers: kpw, llvm-commits
Differential Revision: https://reviews.llvm.org/D32846
llvm-svn: 302210
Summary:
This change allows us to patch/unpatch specific functions using the
function ID. This is useful in cases where implementations might want to
do coverage-style, or more fine-grained control of which functions to
patch or un-patch at runtime.
Depends on D32693.
Reviewers: dblaikie, echristo, kpw
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D32695
llvm-svn: 302112
Summary:
In this patch we document the requirements for implementations that want
to install handlers for the dynamically-controlled XRay "framework".
This clarifies what the expectations are for implementations that
want to install their handlers using this API (similar to how the FDR
logging implementation does so). It also gives users some guarantees on
semantics for the APIs.
If all goes well, users can decide to use the XRay APIs to control the
tracing/logging at the application level, without having to depend on
implementation details of the installed logging implementation. This
lets users choose the implementation that comes with compiler-rt, or
potentially multiple other implementations that use the same APIs.
We also add one convenience function (__xray_remove_log_impl()) for
explicitly removing the currently installed log implementation.
Reviewers: kpw, pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D32579
llvm-svn: 301784
Summary:
This is a follow-up to D32202.
While the previous change (D32202) did fix the stack alignment issue, we
were still at a weird state in terms of the CFI/CFA directives (as the
offsets were wrong). This change cleans up the SAVE/RESTORE macros for
the trampoline, accounting the stack pointer adjustments with less
instructions and with some clearer math. We note that the offsets will
be different on the exit trampolines, because we don't typically 'call'
into this trampoline and we only ever jump into them (i.e. treated as a
tail call that's patched in at runtime).
Reviewers: eugenis, kpw, pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D32214
llvm-svn: 300815
Summary:
Previously, we had been very undisciplined about CFI annotations with
the XRay trampolines. This leads to runtime crashes due to mis-alined
stack pointers that some function implementations may run into (i.e.
those using instructions that require properly aligned addresses coming
from the stack). This patch attempts to clean that up, as well as more
accurately use the correct amounts of space on the stack for stashing
and un-stashing registers.
Reviewers: eugenis, kcc
Subscribers: kpw, llvm-commits
Differential Revision: https://reviews.llvm.org/D32202
llvm-svn: 300660
A problem arises if a machine supports the rdtscp instruction, but the processor
frequency cannot be determined by the function getTSCFrequency(). In this case,
we want to use the emulated TSC instead. This patch implements that by adding a
call to getTSCFrequency() from probeRequiredCPUFeatures(), and the function only
returns true if both the processor supports rdtscp and the CPU frequency can be
determined.
This should fix PR32620.
Reviewers: dberris
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D32067
llvm-svn: 300525
Summary:
While there, make the threshold in ticks for the rewind computed only
once and not per function, unify the two versions we had and slightly
reformat bits according to coding standards.
Reviewers: dberris
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31971
llvm-svn: 300028
Summary:
Not repeating screamy failure paths makes the 300+ line function a bit shorter.
There's no need to overload the variable name "Buffer" if it only works on the
thread local buffer. Fix some comments while there.
I plan to move the rewinding logic into a separate function too, but in this
diff it would be too much of a mess to comprehend. This is trivially NFC.
Reviewers: kpw, dberris
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31930
llvm-svn: 300018
This patch applies a work-around to the XRay FDR tests when TSC emulation is
needed because the processor frequency cannot be determined.
This fixes PR32620 using the suggestion given by Dean in comment 1.
Reviewers: dberris
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31967
llvm-svn: 300017
Previously in r297800, a work-around was created to use TSC emulation on x86_64 when RDTSCP was not available on the host. A similar change was needed in the file xray_fdr_logging.cc which this patch ports over to that file.
Eventually the code should be refactored as there will be 3 locations with the same code, but that can be done as a separate step. This patch is just to keep the test from failing on my machine due to an illegal instruction since RDTSCP is not available on my x86_64 linux VM.
Reviewers: dberris
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31909
llvm-svn: 299922
Summary:
We can move this functionality into LLVM's tools instead, as it no
longer is strictly required for the compiler-rt testing infrastructure.
It also is blocking the successful bootstrapping of the clang compiler
due to a missing virtual destructor in one of the flag parsing library.
Since this binary isn't critical for the XRay runtime testing effort
anymore (yet), we remove it in the meantime with the hope of moving the
functionality in LLVM proper instead.
Reviewers: kpw, pelikan, rnk, seurer, eugenis
Subscribers: llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D31926
llvm-svn: 299916
Summary:
"short" is defined as an xray flag, and buffer rewinding happens for both exits
and tail exits.
I've made the choice to seek backwards finding pairs of FunctionEntry, TailExit
record pairs and erasing them if the FunctionEntry occurred before exit from the
currently exiting function. This is a compromise so that we don't skip logging
tail calls if the function that they call into takes longer our duration.
This works by counting the consecutive function and function entry, tail exit
pairs that proceed the current point in the buffer. The buffer is rewound to
check whether these entry points happened recently enough to be erased.
It is still possible we will omit them if they call into a child function that
is not instrumented which calls a fast grandchild that is instrumented before
doing other processing.
Reviewers: pelikan, dberris
Reviewed By: dberris
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31345
llvm-svn: 299629
Summary:
Currently the FDR log writer, upon flushing, dumps a sequence of buffers from
its freelist to disk. A reader can read the first buffer up to an EOB record,
but then it is unclear how far ahead to scan to find the next threads traces.
There are a few ways to handle this problem.
1. The reader has externalized knowledge of the buffer size.
2. The size of buffers is in the file header or otherwise encoded in the log.
3. Only write out the portion of the buffer with records. When released, the
buffers are marked with a size.
4. The reader looks for memory that matches a pattern and synchronizes on it.
2 and 3 seem the most flexible and 2 does not rule 3 out.
This is an implementation of 2.
In addition, the function handler for fdr more aggressively checks for
finalization and makes an attempt to release its buffer.
Reviewers: pelikan, dberris
Reviewed By: dberris
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31384
llvm-svn: 298982
Summary:
This change exercises the end-to-end functionality defined in the FDR
logging implementation. We also prepare for being able to run traces
generated by the FDR logging implementation from being analysed with the
llvm-xray command that comes with the LLVM distribution.
This also unblocks D31385, D31384, and D31345.
Reviewers: kpw, pelikan
Subscribers: llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D31452
llvm-svn: 298977
In file included from /home/abuild/rpmbuild/BUILD/llvm/projects/compiler-rt/lib/xray/tests/unit/xray_fdr_log_printer_tool.cc:15:
../projects/compiler-rt/lib/xray/tests/../xray_fdr_logging_impl.h:221:21: error: use of undeclared identifier 'CLOCK_MONOTONIC'
wall_clock_reader(CLOCK_MONOTONIC, &TS);
^
1 error generated.
llvm-svn: 298837
Instead of std::atomic APIs for atomic operations, we instead use APIs
include with sanitizer_common. This allows us to, at runtime, not have
to depend on potentially dynamically provided implementations of these
atomic operations.
Fixes http://llvm.org/PR32274.
llvm-svn: 298833
Summary: Fd needs to be closed before the number gets out of scope.
Reviewers: dberris
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31278
llvm-svn: 298685
Summary:
Depending on C++11 <system_error> introduces a link-time requirement to
C++11 symbols. Removing it allows us to depend on header-only C++11 and
up libraries.
Partially fixes http://llvm.org/PR32274 -- we know there's more invasive work
to be done, but we're doing it incrementally.
Reviewers: dblaikie, kpw, pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31233
llvm-svn: 298480
Summary:
Separated the IO and the thread local storage state machine of logging
from the writing of log records once the contents are deterministic.
Finer granularity functions are provided as inline functions in the same
header such that stack does not grow due to the functions being separated.
An executable utility xray_fdr_log_printer is also implemented to use the
finest granularity functions to produce binary test data in the FDR format
with a relatively convenient text input.
For example, one can take a file with textual contents layed out in rows
and feed it to the binary to generate data that llvm-xray convert can then
read. This is a convenient way to build a test suite for llvm-xray convert
to ensure it's robust to the fdr format.
Example:
$cat myFile.txt
NewBuffer : { time = 2 , Tid=5}
NewCPU : { CPU =1 , TSC = 123}
Function : { FuncId = 5, TSCDelta = 3, EntryType = Entry }
Function : { FuncId = 5, TSCDelta = 5, EntryType = Exit}
TSCWrap : { TSC = 678 }
Function : { FuncId = 6, TSCDelta = 0, EntryType = Entry }
Function : { FuncId = 6, TSCDelta = 50, EntryType = Exit }
EOB : { }
$cat myFile.txt | ./bin/xray_fdr_log_printer > /tmp/binarydata.bin
$./bin/llvm-xray convert -output-format=yaml -output=- /tmp/binarydata.bin
yaml format comes out as expected.
Reviewers: dberris, pelikan
Reviewed By: dberris
Subscribers: llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D30850
llvm-svn: 297801
Summary:
Use TSC emulation in cases where RDTSCP isn't available on the host
running an XRay instrumented binary. We can then fall back into
emulation instead of not even installing XRay's runtime functionality.
We only do this for now in the naive/basic logging implementation, but
should be useful in even FDR mode.
Should fix http://llvm.org/PR32148.
Reviewers: pelikan, rnk, sdardis
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D30677
llvm-svn: 297800
rL297000 forgot to include code for three architectures that appeared
since I wrote the first version. This gives them the same treatment as ARMs
have for now - write stubs and wait for someone to actually implement it.
Patched by pelikan (Martin Pelikán)!
Differential Revision: https://reviews.llvm.org/D30634
llvm-svn: 297003
Summary:
Functions with the LOG_ARGS_ENTRY sled kind at their beginning will be handled
in a way to (optionally) pass their first call argument to your logging handler.
For practical and performance reasons, only the first argument is supported, and
only up to 64 bits.
Reviewers: javed.absar, dberris
Reviewed By: dberris
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D29703
llvm-svn: 297000
Summary:
Use a common definition of a "this variable is unused" annotation for useless
variables only present for their lambda global initializers, to silence gcc's
warning.
Reviewers: dberris
Reviewed By: dberris
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D29860
llvm-svn: 296449
Summary:
Currently, we assume that applications built with XRay would like to
have the instrumentation sleds patched before main starts. This patch
changes the default so that we do not patch the instrumentation sleds
before main. This default is more helpful for deploying applications in
environments where changing the current default is harder (i.e. on
remote machines, or work-pool-like systems).
This default (not to patch pre-main) makes it easier to selectively run
applications with XRay instrumentation enabled, than with the current
state.
Reviewers: echristo, timshen
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D30396
llvm-svn: 296445
Summary:
Currently, defaulted options cannot be overriden easily. As an example,
we always patch the binary pre-main unless the user defines the option
at the commandline to inhibit this behaviour. This change allows for
building different versions of the XRay archive with different defaults
(whether to patch pre-main, or whether to use FDR mode by default, etc.)
and giving that choice at link-time.
For now we don't create different archives that have different defaults,
but those could be added in later revisions. This change just enables
the possibility.
Reviewers: pelikan, kcc
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D30022
llvm-svn: 295534
Revert "Fix -Wsign-compare - this might not be quite right, but preserves behavior"
Revert "[XRay] Implement powerpc64le xray."
This reverts commit r294826.
This reverts commit r294781.
llvm-svn: 294842
Summary:
powerpc64 big-endian is not supported, but I believe that most logic can
be shared, except for xray_powerpc64.cc.
Also add a function InvalidateInstructionCache to xray_util.h, which is
copied from llvm/Support/Memory.cpp. I'm not sure if I need to add a unittest,
and I don't know how.
Reviewers: dberris, echristo, iteratee, kbarton, hfinkel
Subscribers: mehdi_amini, nemanjai, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D29742
llvm-svn: 294781
Summary:
The implementation, however, is in different arch-specific files, unless it's emulated.
Reviewers: dberris, pelikan, javed.absar
Subscribers: aemerson, llvm-commits
Differential Revision: https://reviews.llvm.org/D29796
llvm-svn: 294777
Summary:
Fixing a bug I found when testing a reader for the FDR format. Function ID is
now correctly packed into the 28 bits which are documented for it instead of being
masked to all ones.
Reviewers: dberris, pelikan, eugenis
Reviewed By: dberris
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D29698
llvm-svn: 294563
Summary:
As pointed out in casual reading of the XRay codebase, that we had
some interesting named functions that didn't quite follow the LLVM coding
conventions.
Reviewers: chandlerc, dblaikie
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D29625
llvm-svn: 294373
Summary:
This was pointed out that FDR mode didn't quite put the thread ID in the
buffers, but instead would write down the parent process ID.
Reviewers: pelikan, rSerge
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D29484
llvm-svn: 294166
Summary:
In llvm.org/PR31756 it's pointed out that sometimes rdtscp isn't
available. We fix it here by checking first whether it's availble before
installing the logging handler. In future commits we can have
alternative implementations, maybe working around some of the
constraints on some systems.
This change enables us to make that determination, but report an error
instead when the features aren't available.
Reviewers: sdardis, javed.absar, rSerge
Subscribers: pelikan, llvm-commits
Differential Revision: https://reviews.llvm.org/D29438
llvm-svn: 293870
Summary:
This patch provides more staging for tail calls in XRay Arm32 . When the logging part of XRay is ready for tail calls, its support in the core part of XRay Arm32 may be as easy as changing the number passed to the handler from 1 to 2.
Coupled patch:
- https://reviews.llvm.org/D28673
Reviewers: dberris, rengolin
Reviewed By: dberris, rengolin
Subscribers: llvm-commits, iid_iunknown, aemerson
Differential Revision: https://reviews.llvm.org/D28674
llvm-svn: 293186
Summary:
This patch provides a trampoline for function tail exit tracing. Still, it's staging because code `1` is passed to the handler function (indicating a normal exit) instead of `2`, which would indicate tail exit. This is so until the logging part of XRay supports tail exits too.
Related: https://reviews.llvm.org/D28947 (LLVM)
Reviewers: dberris, rengolin
Reviewed By: rengolin
Subscribers: aemerson, llvm-commits, iid_iunknown
Differential Revision: https://reviews.llvm.org/D28948
llvm-svn: 293082
Summary:
In this change we introduce the notion of a "flight data recorder" mode
for XRay logging, where XRay logs in-memory first, and write out data
on-demand as required (as opposed to the naive implementation that keeps
logging while tracing is "on"). This depends on D26232 where we
implement the core data structure for holding the buffers that threads
will be using to write out records of operation.
This implementation only currently works on x86_64 and depends heavily
on the TSC math to write out smaller records to the inmemory buffers.
Also, this implementation defines two different kinds of records with
different sizes (compared to the current naive implementation): a
MetadataRecord (16 bytes) and a FunctionRecord (8 bytes). MetadataRecord
entries are meant to write out information like the thread ID for which
the metadata record is defined for, whether the execution of a thread
moved to a different CPU, etc. while a FunctionRecord represents the
different kinds of function call entry/exit records we might encounter
in the course of a thread's execution along with a delta from the last
time the logging handler was called.
While this implementation is not exactly what is described in the
original XRay whitepaper, this one gives us an initial implementation
that we can iterate and build upon.
Reviewers: echristo, rSerge, majnemer
Subscribers: mehdi_amini, llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D27038
llvm-svn: 293015
Summary:
Testing of XRay was occasionally disabled on 32-bit Arm targets (someone assumed that XRay was supported on 64-bit targets only). This patch should fix that problem. Also here the instruction&data cache incoherency problem is fixed, because it may be causing a test to fail.
This patch is one of a series: see also
- https://reviews.llvm.org/D28624
Reviewers: dberris, rengolin
Reviewed By: rengolin
Subscribers: llvm-commits, aemerson, rengolin, dberris, iid_iunknown
Differential Revision: https://reviews.llvm.org/D28623
llvm-svn: 292517
This reverts commit r292211, as it broke the Thumb buldbot with:
clang-5.0: error: the clang compiler does not support '-fxray-instrument
on thumbv7-unknown-linux-gnueabihf'
llvm-svn: 292356
Summary:
Testing of XRay was occasionally disabled on 32-bit Arm targets (someone assumed that XRay was supported on 64-bit targets only). This patch should fix that problem. Also here the instruction&data cache incoherency problem is fixed, because it may be causing a test to fail.
This patch is one of a series: see also
- https://reviews.llvm.org/D28624
Reviewers: dberris, rengolin
Reviewed By: rengolin
Subscribers: llvm-commits, aemerson, rengolin, dberris, iid_iunknown
Differential Revision: https://reviews.llvm.org/D28623
llvm-svn: 292211
Summary: This patch attempts to fix test patching-unpatching.cc . The new code flushes the instruction cache after modifying the program at runtime.
Reviewers: dberris, rengolin, pelikan, rovka
Subscribers: rovka, llvm-commits, iid_iunknown, aemerson
Differential Revision: https://reviews.llvm.org/D27996
llvm-svn: 291568
Summary:
If you decide to recompile parts of your Linux distro with XRay, it may
be useful to know which trace belongs to which binary. While there, get
rid of the incorrect strncat() usage; it always returns a pointer to the
start which makes that if() always true. Replace with snprintf which is
bounded so that enough from both strings fits nicely.
Reviewers: dberris
Subscribers: danalbert, srhines, kubabrecka, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D27912
llvm-svn: 290861
Summary:
In this change we introduce the notion of a "flight data recorder" mode
for XRay logging, where XRay logs in-memory first, and write out data
on-demand as required (as opposed to the naive implementation that keeps
logging while tracing is "on"). This depends on D26232 where we
implement the core data structure for holding the buffers that threads
will be using to write out records of operation.
This implementation only currently works on x86_64 and depends heavily
on the TSC math to write out smaller records to the inmemory buffers.
Also, this implementation defines two different kinds of records with
different sizes (compared to the current naive implementation): a
MetadataRecord (16 bytes) and a FunctionRecord (8 bytes). MetadataRecord
entries are meant to write out information like the thread ID for which
the metadata record is defined for, whether the execution of a thread
moved to a different CPU, etc. while a FunctionRecord represents the
different kinds of function call entry/exit records we might encounter
in the course of a thread's execution along with a delta from the last
time the logging handler was called.
While this implementation is not exactly what is described in the
original XRay whitepaper, this one gives us an initial implementation
that we can iterate and build upon.
Reviewers: echristo, rSerge, majnemer
Subscribers: mehdi_amini, llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D27038
llvm-svn: 290852
Summary: This patch attempts to fix test patching-unpatching.cc . The new code flushes the instruction cache after modifying the program at runtime.
Reviewers: dberris, rengolin
Subscribers: llvm-commits, iid_iunknown, aemerson
Differential Revision: https://reviews.llvm.org/D27996
llvm-svn: 290452
Summary: This patch attempts to fix test patching-unpatching.cc . The new code flushes the instruction cache after modifying the program at runtime.
Reviewers: dberris, rengolin
Subscribers: llvm-commits, iid_iunknown, aemerson
Differential Revision: https://reviews.llvm.org/D27996
llvm-svn: 290354
Missed a couple of files:
- Using #pragma once
- Missing top-matter for headers
- Missing an include for <cstdint>
Follow-up on D25360.
llvm-svn: 290079
Summary:
Getting rid of the distance number altogether because:
- a person knowledgeable enough to know what the message means will also
know how to do hexadecimal math (with the help of a calculator)
- numbers outside INT_MIN - INT_MAX are hard to comprehend anyway
This unbreaks the case when you dynamically link a library with XRay and
it exits pre-main() with a not very informative static string.
Author: pelikan
Reviewers: dberris
Subscribers: llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D27894
llvm-svn: 290074
projects/compiler-rt/lib/xray/xray_trampoline_x86_64.S:33:7: error: unexpected token in '.endm' directive
.endm SAVE_REGISTERS
^
projects/compiler-rt/lib/xray/xray_trampoline_x86_64.S:52:7: error: unexpected token in '.endm' directive
.endm RESTORE_REGISTERS
^
Remove the trailing name on the `.endm` which does not take the name of the
macro. This should bring the compiler-rt build bot back into working state.
llvm-svn: 289852
Summary:
The layout of all registers saved on stack shouldn't deviate and will be reused in future trampolines as well.
While there, fix whitespace and clarify comments.
Author: mpel
Reviewers: dberris
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D27799
llvm-svn: 289789
Summary:
This should improve the error messages generated providing a bit more
information when the failures are printed out. One example of a
contrived error looks like:
```
Expected: (Buffers.getBuffer(Buf)) != (std::error_code()), actual:
system:0 vs system:0
```
Because we're using error codes, the default printing gets us more
useful information in case of failure.
This is a follow-up on D26232.
Reviewers: rSerge
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D27495
llvm-svn: 289501
As constructed before this patch, in case we run into case where we
don't actually build the XRay library, we really ought to not be adding
the unit test runs. This should fix the bootstrap build failures.
This is a follow-up further to D26232.
llvm-svn: 288788
Before this, the change committed in D26232 might have an uninitialised
std::atomic<bool> that may or may not have a valid state. On aarch64
this breaks consistently, while it doesn't manifest as a problem in
x86_64.
This is an attempt to un-break this in aarch64.
llvm-svn: 288776
This implements a simple buffer queue to manage a pre-allocated queue of
fixed-sized buffers to hold XRay records. We need this to support
Flight Data Recorder (FDR) mode. We also implement this as a sub-library
first to allow for development before actually using it in an
implementation.
Some important properties of the buffer queue:
- Thread-safe enqueueing/dequeueing of fixed-size buffers.
- Pre-allocation of buffers at construction.
This is a re-roll of the previous attempt to submit, because it caused
failures in arm and aarch64.
Reviewers: majnemer, echristo, rSerge
Subscribers: tberghammer, danalbert, srhines, modocache, mehdi_amini, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D26232
llvm-svn: 288775
Summary: Currently test XRay-aarch64-linux::patching-unpatching.cc sometimes passes, sometimes fails. This is an attempt to fix it by handling better the situations when both `__arm__` and `__aarch64__` are defined.
Reviewers: dberris, rengolin
Subscribers: llvm-commits, iid_iunknown, aemerson, rengolin, dberris
Differential Revision: https://reviews.llvm.org/D27421
llvm-svn: 288729
Summary:
This implements a simple buffer queue to manage a pre-allocated queue of
fixed-sized buffers to hold XRay records. We need this to support
Flight Data Recorder (FDR) mode. We also implement this as a sub-library
first to allow for development before actually using it in an
implementation.
Some important properties of the buffer queue:
- Thread-safe enqueueing/dequeueing of fixed-size buffers.
- Pre-allocation of buffers at construction.
Reviewers: majnemer, rSerge, echristo
Subscribers: mehdi_amini, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D26232
llvm-svn: 287910
This goes through all the calls to `Report(...)` to make sure that each
one would have a newline at the end of the message for readability.
llvm-svn: 287736
Include xray_defs.h in xray_arm.cc (seems to be the only one that doesn't
include it).
Buildbot errors:
[...]/compiler-rt/lib/xray/xray_arm.cc:31:58: error: expected initializer before 'XRAY_NEVER_INSTRUMENT'
inline static uint32_t getMovwMask(const uint32_t Value) XRAY_NEVER_INSTRUMENT {
llvm-svn: 287089
Summary:
Adds a CMake check for whether the compiler used to build the XRay
library supports XRay-instrumentation. If the compiler we're using does
support the `-fxray-instrument` flag (i.e. recently-built Clang), we
define the XRAY_NEVER_INSTRUMENT macro that then makes sure that the
XRay runtime functions never get XRay-instrumented.
This prevents potential weirdness involved with building the XRay
library with a Clang that supports XRay-instrumentation, and is
attempting to XRay-instrument the build of compiler-rt.
Reviewers: majnemer, rSerge, echristo
Subscribers: mehdi_amini, llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D26597
llvm-svn: 287068
Summary:
We define a new trampoline that's a hybrid between the exit and entry
trampolines with the following properties:
- Saves all of the callee-saved registers according to the x86_64
calling conventions.
- Indicate to the log handler function being called that this is a
function exit event.
This fixes a bug that is a result of not saving enough of the register
states, and that the log handler is clobbering registers that would be
used by the function being tail-exited into manifesting as runtime
errors.
Reviewers: rSerge, echristo, majnemer
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D26020
llvm-svn: 285787
Summary:
This change depends on D23986 which adds tail call-specific sleds. For
now we treat them first as normal exits, and in the future leave room
for implementing this as a different kind of log entry.
The reason for deferring the change is so that we can keep the naive
logging implementation more accurate without additional complexity for
reading the log. The accuracy is gained in effectively interpreting call
stacks like:
A()
B()
C()
Which when tail-call merged will end up not having any exit entries for
A() nor B(), but effectively in turn can be reasoned about as:
A()
B()
C()
Although we lose the fact that A() had called B() then had called C()
with the naive approach, a later iteration that adds the explicit tail
call entries would be a change in the log format and thus necessitate a
version change for the header. We can do this later to have a chance at
releasing some tools (in D21987) that are able to handle the naive log
format, then support higher version numbers of the log format too.
Reviewers: echristo, kcc, rSerge, majnemer
Subscribers: mehdi_amini, llvm-commits, dberris
Differential Revision: https://reviews.llvm.org/D23988
llvm-svn: 284178
The definitions in sanitizer_common may conflict with definitions from system headers because:
The runtime includes the system headers after the project headers (as per LLVM coding guidelines).
lib/sanitizer_common/sanitizer_internal_defs.h pollutes the namespace of everything defined after it, which is all/most of the sanitizer .h and .cc files and the included system headers with: using namespace __sanitizer; // NOLINT
This patch solves the problem by introducing the namespace only within the sanitizer namespaces as proposed by Dmitry.
Differential Revision: https://reviews.llvm.org/D21947
llvm-svn: 281657
This patch builds on LLVM r279776.
In this patch I've done some cleanup and abstracted three common steps runtime components have in their CMakeLists files, and added a fourth.
The three steps I abstract are:
(1) Add a top-level target (i.e asan, msan, ...)
(2) Set the target properties for sorting files in IDE generators
(3) Make the compiler-rt target depend on the top-level target
The new step is to check if a command named "runtime_register_component" is defined, and to call it with the component name.
The runtime_register_component command is defined in llvm/runtimes/CMakeLists.txt, and presently just adds the component to a list of sub-components, which later gets used to generate target mappings.
With this patch a new workflow for runtimes builds is supported. The new workflow when building runtimes from the LLVM runtimes directory is:
> cmake [...]
> ninja runtimes-configure
> ninja asan
The "runtimes-configure" target builds all the dependencies for configuring the runtimes projects, and runs CMake on the runtimes projects. Running the runtimes CMake generates a list of targets to bind into the top-level CMake so subsequent build invocations will have access to some of Compiler-RT's targets through the top-level build.
Note: This patch does exclude some top-level targets from compiler-rt libraries because they either don't install files (sanitizer_common), or don't have a cooresponding `check` target (stats).
llvm-svn: 279863
Depends on D21612 which implements the building blocks for the compiler-rt
implementation of the XRay runtime. We use a naive in-memory log of fixed-size
entries that get written out to a log file when the buffers are full, and when
the thread exits.
This implementation lays some foundations on to allowing for more complex XRay
records to be written to the log in subsequent changes. It also defines the format
that the function call accounting tool in D21987 will start building upon.
Once D21987 lands, we should be able to start defining more tests using that tool
once the function call accounting tool becomes part of the llvm distribution.
Reviewers: echristo, kcc, rnk, eugenis, majnemer, rSerge
Subscribers: sdardis, rSerge, dberris, tberghammer, danalbert, srhines, majnemer, llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D21982
llvm-svn: 279805
Summary:
We also add one test (and the XRay testing infrastructure) to exercise
the patching and unpatching code. This uses the XRay API exported
through the headers as well, installing a custom log handler.
Depends on D23101 for the updated emitted code alignment for the
return/entry sleds.
Reviewers: rSerge, echristo, rnk
Subscribers: tberghammer, danalbert, srhines, mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D23154
llvm-svn: 277971
We now stash and restore the xmm registers in the trampolines so that
log handlers don't need to worry about clobbering these registers.
In response to comments in D21612.
Reviewers: rSerge, eugenis, echristo, rnk
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D23051
llvm-svn: 277683
This addresses some comments from D21612, which contains the following changes:
- Update __xray_patch() and __xray_unpatch() API documentation to not imply asynchrony.
- Introduce a scope cleanup mechanism to make sure we can roll-back changes to the XRayPatching global atomic.
- Introduce a few more comments for potential extension points for other platforms (for the implementation details of patching and un-patching).
Reviewers: eugenis, rnk, kcc, echristo, majnemer
Subscribers: llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D22911
llvm-svn: 277124
Summary:
This is a fixed-up version of D21612, to address failure identified post-commit.
Original commit description:
This patch implements the initialisation and patching routines for the XRay runtime, along with the necessary trampolines for function entry/exit handling. For now we only define the basic hooks for allowing an implementation to define a handler that gets run on function entry/exit. We expose a minimal API for controlling the behaviour of the runtime (patching, cleanup, and setting the handler to invoke when instrumenting).
Fixes include:
- Gating XRay build to only Linux x86_64 and with the right dependencies in case it is the only library being built
- Including <cstddef> to fix std::size_t issue
Reviewers: kcc, rnk, echristo
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D22611
llvm-svn: 276251
and also the follow-up "[xray] Only build xray on Linux for now"
Two build errors were reported on the llvm-commits list:
[ 88%] Building CXX object lib/xray/CMakeFiles/clang_rt.xray-x86_64.dir/xray_flags.cc.o
/mnt/b/sanitizer-buildbot1/sanitizer-x86_64-linux/build/llvm/projects/compiler-rt/lib/xray/xray_init.cc:23:10: fatal error: 'llvm/Support/ELF.h' file not found
#include "llvm/Support/ELF.h"
^
and
In file included from /w/src/llvm.org/projects/compiler-rt/lib/xray/xray_interface.cc:16:
/w/src/llvm.org/projects/compiler-rt/lib/xray/xray_interface_internal.h:36:8: error:
no type named 'size_t' in namespace 'std'
std::size_t Entries;
~~~~~^
llvm-svn: 276186
Summary:
This patch implements the initialisation and patching routines for the XRay runtime, along with the necessary trampolines for function entry/exit handling. For now we only define the basic hooks for allowing an implementation to define a handler that gets run on function entry/exit. We expose a minimal API for controlling the behaviour of the runtime (patching, cleanup, and setting the handler to invoke when instrumenting).
Depends on D19904
Reviewers: echristo, kcc, rnk
Subscribers: rnk, mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D21612
llvm-svn: 276117
Dean Michael Berris