Summary:
Looking at the current Apple-specific code for crash handling it does a few
silly things that I think we should avoid while handling crashes:
* Try real hard not to allocate.
* Set the global crash reporter string early so that any crash while
generating the stack trace will still report some info.
* Prevent reordering of operations in the current thread.
<rdar://problem/53503334>
Subscribers: hiraditya, jkorous, dexonsmith, llvm-commits, beanz, Bigcheese, thakis, lattner, jordan_rose
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65235
llvm-svn: 367031
Support SIGINFO (and SIGUSR1 for POSIX purposes) to tell what
long-running jobs are doing, as inspired by BSD tools (including on
macOS), by dumping the current PrettyStackTrace.
This adds a new kind of signal handler for non-fatal "info" signals,
similar to the "interrupt" handler that already exists for SIGINT
(Ctrl-C). It then uses that handler to update a "generation count"
managed by the PrettyStackTrace infrastructure, which is then checked
whenever a PrettyStackTraceEntry is pushed or popped on each
thread. If the generation has changed---i.e. if the user has pressed
Ctrl-T---the stack trace is dumped, though unfortunately it can't
include the deepest entry because that one is currently being
constructed/destructed.
https://reviews.llvm.org/D63750
llvm-svn: 365911
The autoconf build system support has been removed a while ago, remove
some outdated references.
Differential Revision: https://reviews.llvm.org/D63608
llvm-svn: 365013
Some platforms, e.g. Windows, support backtraces but don't have
BACKTRACE. Checking for BACKTRACE prevents Windows from having
backtraces.
Patch by Jason Mittertreiner!
llvm-svn: 354951
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
We were unnecessarily going from SmallString to std::string just to
get a null-terminated C string. So just...don't do that. Crash
slightly faster!
llvm-svn: 334841
I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.
I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.
This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.
Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).
llvm-svn: 304787
This patch fixes the linkage for __crashtracer_info__, making it have the proper mangling (extern "C") and linkage (private extern).
It also adds a new PrettyStackTrace type, allowing LLDB to adopt this instead of Host::SetCrashDescriptionWithFormat().
Without this patch, CrashTracer on macOS won't pick up pretty stack traces from any LLVM client.
An LLDB commit adopting this API will follow shortly.
Differential Revision: https://reviews.llvm.org/D27683
llvm-svn: 289689
warning: cast from type ‘const void*’ to type
‘llvm::PrettyStackTraceEntry*’ casts away qualifiers [-Wcast-qual]
PrettyStackTraceHead = (PrettyStackTraceEntry*)Top;
llvm-svn: 271069
Type specific declarations have been moved to Type.h and error handling
routines have been moved to ErrorHandling.h. Both are included in Core.h
so nothing should change for projects directly including the headers,
but transitive dependencies may be affected.
llvm-svn: 255965
PrettyStackTraceHead is a LLVM_THREAD_LOCAL, which means it's just a global
in LLVM_ENABLE_THREADS=NO builds. If a CrashRecoveryContext is used with
code that uses PrettyStackEntries, and a crash happens, PrettyStackTraceHead is
currently not reset to its pre-crash value. These functions make it possible
to add a cleanup to such code that does this.
(Not reseting the value then causes the assert in ~PrettyStackTraceEntry() to
fire if the code outside of the CrashRecoveryContext also uses
PrettyStackEntries -- for example, clang when building a module.)
Part of PR11974.
llvm-svn: 244338
This has the nice secondary effect of allowing LLVM to continue to build
for targets without __thread or thread_local support to continue to work
so long as they build without support for backtraces.
llvm-svn: 227423
entirely when threads are not enabled. This should allow anyone who
needs to bootstrap or cope with a host loader without TLS support to
limp along without threading support.
There is still some bug in the PPC TLS stuff that is not worked around.
I'm getting access to a machine to reproduce and debug this further.
There is some chance that I'll have to add a terrible workaround for
PPC.
There is also some problem with iOS, but I have no ability to really
evaluate what the issue is there. I'm leaving it to folks maintaining
that platform to suggest a path forward -- personally I don't see any
useful path forward that supports threading in LLVM but does so without
support for *very basic* TLS. Note that we don't need more than some
pointers, and we don't need constructors, destructors, or any of the
other fanciness which remains widely unimplemented.
llvm-svn: 227411
Sadly, this precludes optimizing it down to initial-exec or local-exec
when statically linking, and in general makes the code slower on PPC 64,
but there's nothing else for it until we can arrange to produce the
correct bits for the linker.
Lots of thanks to Ulirch for tracking this down and Bill for working on
the long-term fix to LLVM so that we can relegate this to old host
clang versions.
I'll be watching the PPC build bots to make sure this effectively
revives them.
llvm-svn: 227352
tracing code.
Managed static was just insane overhead for this. We took memory fences
and external function calls in every path that pushed a pretty stack
frame. This includes a multitude of layers setting up and tearing down
passes, the parser in Clang, everywhere. For the regression test suite
or low-overhead JITs, this was contributing to really significant
overhead.
Even the LLVM ThreadLocal is really overkill here because it uses
pthread_{set,get}_specific logic, and has careful code to both allocate
and delete the thread local data. We don't actually want any of that,
and this code in particular has problems coping with deallocation. What
we want is a single TLS pointer that is valid to use during global
construction and during global destruction, any time we want. That is
exactly what every host compiler and OS we use has implemented for
a long time, and what was standardized in C++11. Even though not all of
our host compilers support the thread_local keyword, we can directly use
the platform-specific keywords to get the minimal functionality needed.
Provided this limited trial survives the build bots, I will move this to
Compiler.h so it is more widely available as a light weight if limited
alternative to the ThreadLocal class. Many thanks to David Majnemer for
helping me think through the implications across platforms and craft the
MSVC-compatible syntax.
The end result is *substantially* faster. When running llc in a tight
loop over a small IR file targeting the aarch64 backend, this improves
its performance by over 10% for me. It also seems likely to fix the
remaining regressions seen by JIT users with threading enabled.
This may actually have more impact on real-world compile times due to
the use of the pretty stack tracing utility throughout the rest of Clang
or LLVM, but I've not collected any detailed measurements.
llvm-svn: 227300
subsequent changes are easier to review. About to fix some layering
issues, and wanted to separate out the necessary churn.
Also comment and sink the include of "Windows.h" in three .inc files to
match the usage in Memory.inc.
llvm-svn: 198685
stack traces by default if you use PrettyStackTraceProgram, so that existing LLVM-based
tools will continue to get it without any changes.
llvm-svn: 193971
This was somewhat tricky because ~PrettyStackTraceEntry() may run after
llvm_shutdown() has been called. This is rare and only happens for a common idiom
used in the main() functions of command-line tools. This works around the idiom by
skipping the stack clean-up if the PrettyStackTraceHead ManagedStatic is not
constructed (i.e. llvm_shutdown() has been called).
llvm-svn: 190730
it's only really useful if you're going to crash anyways. Use it in the pretty stack trace
printer to kill the compiler if we hang while printing the stack trace.
llvm-svn: 177962
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.
Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]
llvm-svn: 169131
JF Bastien