When an llvm tool crashes (e.g. from a segmentation fault),
SignalHandler will re-raise the signal. The effect is that crash reports
now contain SignalHandler in the stack trace. The crash reports are
still useful, but the presence of SignalHandler can confuse tooling and
automation that deduplicate or analyze crash reports.
rdar://150464802
This patch is part of a series that adds origin-tracking to the debugify
source location coverage checks, allowing us to report symbolized stack
traces of the point where missing source locations appear.
This patch adds a pair of new functions in `signals.h` that can be used
to collect and symbolize stack traces respectively. This has major
implementation overlap with the existing stack trace
collection/symbolizing methods, but the existing functions are
specialized for dumping a stack trace to stderr when LLVM crashes, while
these new functions are meant to be called repeatedly during the
execution of the program, and therefore we need a separate set of
functions.
In case of an error, the DL_info struct may have been left
uninitialized, so it is not safe to use its members.
In one error case, initialize dli_sname to nullptr explicitly, so that
the later check against nullptr is guaranteed to be safe.
Cygwin types sometimes do not match Linux exactly. Like in this case:
```
In file included from /h/projects/llvm-project/llvm/include/llvm/Support/Error.h:23,
from /h/projects/llvm-project/llvm/include/llvm/Support/FileSystem.h:34,
from /h/projects/llvm-project/llvm/lib/Support/Signals.cpp:22:
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h: In instantiation of ‘llvm::format_object<Ts>::format_object(const char*, const Ts& ...) [with Ts = {int, char [4096]}]’:
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h:126:10: required from ‘llvm::format_object<Ts ...> llvm::format(const char*, const Ts& ...) [with Ts = {int, char [4096]}]’
/h/projects/llvm-project/llvm/lib/Support/Unix/Signals.inc:850:19: required from here
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h:106:34: error: no matching function for call to ‘std::tuple<int, char [4096]>::tuple(const int&, const char [4096])’
106 | : format_object_base(fmt), Vals(vals...) {
| ^~~~~~~~~~~~~
```
Casting here is safe and solves the issue.
Otherwise, the handler "swallows" the signal and the process continues
to execute. While this use case is peculiar, ignoring these signals
entirely seems more odd.
Prevents avoidable memory leaks.
Looks like exchange added in aa1333a91f8d8a060bcf5b14aa32a6e8bab74e8c
didn't take "continue" into account.
```
==llc==2150782==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 10 byte(s) in 1 object(s) allocated from:
#0 0x5f1b0f9ac14a in strdup llvm-project/compiler-rt/lib/asan/asan_interceptors.cpp:593:3
#1 0x5f1b1768428d in FileToRemoveList llvm-project/llvm/lib/Support/Unix/Signals.inc:105:55
```
These are unneeded even on AIX, PURE_WINDOWS, and ZOS (per #104706)
* HAVE_ERRNO_H: introduced by 1a93330ffa2ae2aa0b49461f05e6f0d51e8443f8 (2009) but unneeded.
The guarded ABI is unconditionally used by lldb.
* HAVE_FCNTL_H
* HAVE_FENV_H
* HAVE_SYS_STAT_H
Pull Request: https://github.com/llvm/llvm-project/pull/123087
The system call `__CELQTBCK()` is used to build a backtrace like
on other systems. The collected information are the address of the PC,
the address of the entry point (EP), the difference between both
addresses (+EP), the dynamic storage area (DSA aka the stack
pointer), and the function name.
The system call is described here:
https://www.ibm.com/docs/en/zos/3.1.0?topic=cwicsa6a-celqtbck-also-known-as-celqtbck-64-bit-traceback-service
This corrects a Darwin build failure due to a missing stub and an
environment-specific Linux test failure due to an overly restrictive
test regex. This also backs out of the previous fix attempt; %p is
intended to be printed and parsed with the semantics of #.
When the environment LLVM_ENABLE_SYMBOLIZER_MARKUP is set, if
llvm-symbolizer fails or is disabled, this change will print a backtrace
in llvm-symbolizer markup instead of falling back to in-process
symbolization mechanisms.
This allows llvm-symbolizer to be run on the output later to produce a
high quality backtrace, even for fully-stripped LLVM utilities.
Reviewed By: mcgrathr
Differential Revision: https://reviews.llvm.org/D139750
No call sites interpreted this value meaningfully. Simplify this
interface.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D149707
To have line number information in stack traces (per stack frame) it's
necessary to implement findModulesAndOffsets.
Differential Revision: https://reviews.llvm.org/D142282
To have line number information in stack traces (per stack frame) it's
necessary to implement findModulesAndOffsets.
Differential Revision: https://reviews.llvm.org/D142282
Apply clang-format on llvm/lib/Support/Windows/ and llvm/lib/Support/Unix/ since .inc files in these folders aren't picked up by default. Eventually we need to add this extension in the monorepo .clang-format file.
Differential Revision: https://reviews.llvm.org/D138714
This patch is spamming compiles with unhelpful and confusing messages.
E.g. the Linux kernel uses "grep -q" in several places. It's meant to
quit with a return code of zero when the first match is found. This can
cause a SIGPIPE signal, but that's expected, and there's no way to turn
this error message off to avoid spurious error messages.
UNIX03 apparently doesn't require printing an error message on SIGPIPE,
but specifically when there's an error on the stdout stream in a normal
program flow, e.g. when SIGPIPE trap is disabled.
A separate patch is planned to address the specific case we care most
about (involving llvm-nm).
This reverts commit b89bcefa6202e310eb3167dd1c37f1807377ec8d.
Link: https://github.com/llvm/llvm-project/issues/59037
Link: https://github.com/ClangBuiltLinux/linux/issues/1651
Differential Revision: https://reviews.llvm.org/D138244
LLVM contains a helpful function for getting the size of a C-style
array: `llvm::array_lengthof`. This is useful prior to C++17, but not as
helpful for C++17 or later: `std::size` already has support for C-style
arrays.
Change call sites to use `std::size` instead.
Differential Revision: https://reviews.llvm.org/D133429
UNIX03 conformance requires utilities to flush stdout before exiting and raise
an error if writing fails. Flushing already happens on a call to exit
and thus automatically on a return from main. Write failure is then
detected by LLVM's default SIGPIPE handler. The handler already exits with
a non-zero code, but conformance additionally requires an error message.
First reapply attempt I hadn't noticed the test had changed, hopefully this
goes better.
UNIX03 conformance requires utilities to flush stdout before exiting and raise
an error if writing fails. Flushing already happens on a call to exit
and thus automatically on a return from main. Write failure is then
detected by LLVM's default SIGPIPE handler. The handler already exits with
a non-zero code, but conformance additionally requires an error message.
UNIX03 conformance requires utilities to flush stdout before exiting and raise
an error if writing fails. Flushing already happens on a call to exit
and thus automatically on a return from main. Write failure is then
detected by LLVM's default SIGPIPE handler. The handler already exits with
a non-zero code, but conformance additionally requires an error message.
This reverts commit ef8206320769ad31422a803a0d6de6077fd231d2.
- It conflicts with the existing llvm::size in STLExtras, which will now
never be called.
- Calling it without llvm:: breaks C++17 compat
Note to BuryPointer.cpp:GraveYard. 'unused' cannot prevent (1) dead store
elimination and (2) removal of the global pointer variable (D69428) but 'used' can.
Discovered when comparing link maps between HEAD+D69428 and HEAD.
Reviewed By: lattner
Differential Revision: https://reviews.llvm.org/D101217
Most users of LLVM tools hit the raw traces and don't know how to get LLVM to
symbolize automatically for them.
When we print the non-symbolized stack trace, we will add information about
how to get it symbolized.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D88269
Before this patch, the CrashRecoveryContext was returning -2 upon a signal, like ExecuteAndWait does. This didn't match the behavior on Windows, where the the exception code was returned.
We now return the signal's code, which optionally allows for re-throwing the signal later. Doing so requires all custom handlers to be removed first, through llvm::sys::unregisterHandlers() which we made a public API.
This is part of https://reviews.llvm.org/D70378
The non-standard header file `<sysexits.h>` provides some return values.
`EX_IOERR` is used to as a special value to signal a broken pipe to the clang driver.
On z/OS Unix System Services, this header file does not exists. This patch
- adds a check for `<sysexits.h>`, removing the dependency on `LLVM_ON_UNIX`
- adds a new header file `llvm/Support/ExitCodes`, which either includes
`<sysexits.h>` or defines `EX_IOERR`
- updates the users of `EX_IOERR` to include the new header file
Reviewed By: hubert.reinterpretcast
Differential Revision: https://reviews.llvm.org/D83472
This patch allows for handling a failure inside a CrashRecoveryContext in the same way as the global exception/signal handler. A failure will have the same side-effect, such as cleanup of temporarty file, printing callstack, calling relevant signal handlers, and finally returning an exception code. This is an optional feature, disabled by default.
This is a support patch for D69825.
Differential Revision: https://reviews.llvm.org/D70568
As SIGPIPE is no longer in the IntSigs array, handle SIGPIPE before
handling any interrupt signals.
Thanks to Alexandre Ganea for pointing out the issue here.
Allow clients of the llvm library to opt-in to one-shot SIGPIPE
handling, instead of forcing them to undo llvm's SIGPIPE handler
registration (which is brittle).
The current behavior is preserved for all llvm-derived tools (except
lldb) by means of a default-`true` flag in the InitLLVM constructor.
This prevents "IO error" crashes in long-lived processes (lldb is the
motivating example) which both a) load llvm as a dynamic library and b)
*really* need to ignore SIGPIPE.
As llvm signal handlers can be installed when calling into libclang
(say, via RemoveFileOnSignal), thereby overriding a previous SIG_IGN for
SIGPIPE, there is no clean way to opt-out of "exit-on-SIGPIPE" in the
current model.
Differential Revision: https://reviews.llvm.org/D70277
This reverts commit 32ce14e55e5a99dd99c3b4fd4bd0ccaaf2948c30.
In post-commit review, Pavel pointed out that there's a simpler way to
ignore SIGPIPE in lldb that doesn't rely on llvm's handlers.
Occasionally, during test teardown, LLDB writes to a closed pipe.
Sometimes the communication is inherently unreliable, so LLDB tries to
avoid being killed due to SIGPIPE (it calls `signal(SIGPIPE, SIG_IGN)`).
However, LLVM's default SIGPIPE behavior overrides LLDB's, causing it to
exit with IO_ERR.
Opt LLDB out of the default SIGPIPE behavior. I expect that this will
resolve some LLDB test suite flakiness (tests randomly failing with
IO_ERR) that we've seen since r344372.
rdar://55750240
Differential Revision: https://reviews.llvm.org/D69148
llvm-svn: 375288
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
Use '%tu' modifier for pointer arithmetic since we are using C++11
already. Prefer static_cast<> over C-style cast. Remove unnecessary
conversion of result, and add const qualifier to converted pointers,
to silence the following warning:
In file included from /home/mgorny/llvm-project/llvm/lib/Support/Signals.cpp:220:0:
/home/mgorny/llvm-project/llvm/lib/Support/Unix/Signals.inc: In function ‘void llvm::sys::PrintStackTrace(llvm::raw_ostream&)’:
/home/mgorny/llvm-project/llvm/lib/Support/Unix/Signals.inc:546:53: warning: cast from type ‘const void*’ to type ‘char*’ casts away qualifiers [-Wcast-qual]
(char*)dlinfo.dli_saddr));
^~~~~~~~~
Differential Revision: https://reviews.llvm.org/D63888
llvm-svn: 364912
