[llvm-symbolizer] Omit stderr output when symbolizing a crash

Differential revision: https://reviews.llvm.org/D55723

llvm-svn: 349516

Refactor ExecuteAndWait to take StringRefs.

This simplifies some code which had StringRefs to begin with, and
makes other code more complicated which had const char* to begin
with.

In the end, I th

Refactor ExecuteAndWait to take StringRefs.

This simplifies some code which had StringRefs to begin with, and
makes other code more complicated which had const char* to begin
with.

In the end, I think this makes for a more idiomatic and platform
agnostic API. Not all platforms launch process with null terminated
c-string arrays for the environment pointer and argv, but the api
was designed that way because it allowed easy pass-through for
posix-based platforms. There's a little additional overhead now
since on posix based platforms we'll be takign StringRefs which
were constructed from null terminated strings and then copying
them to null terminate them again, but from a readability and
usability standpoint of the API user, I think this API signature
is strictly better.

llvm-svn: 334518

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Signal handling should be signal-safe

Summary:
Before this patch, signal handling wasn't signal safe. This leads to real-world
crashes. It used ManagedStatic inside of signals, this can allocate and

Signal handling should be signal-safe

Summary:
Before this patch, signal handling wasn't signal safe. This leads to real-world
crashes. It used ManagedStatic inside of signals, this can allocate and can lead
to unexpected state when a signal occurs during llvm_shutdown (because
llvm_shutdown destroys the ManagedStatic). It also used cl::opt without custom
backing storage. Some de-allocation was performed as well. Acquiring a lock in a
signal handler is also a great way to deadlock.

We can't just disable signals on llvm_shutdown because the signals might do
useful work during that shutdown. We also can't just disable llvm_shutdown for
programs (instead of library uses of clang) because we'd have to then mark the
pointers as not leaked and make sure all the ManagedStatic uses are OK to leak
and remain so.

Move all of the code to lock-free datastructures instead, and avoid having any
of them in an inconsistent state. I'm not trying to be fancy, I'm not using any
explicit memory order because this code isn't hot. The only purpose of the
atomics is to guarantee that a signal firing on the same or a different thread
doesn't see an inconsistent state and crash. In some cases we might miss some
state (for example, we might fail to delete a temporary file), but that's fine.

Note that I haven't touched any of the backtrace support despite it not
technically being totally signal-safe. When that code is called we know
something bad is up and we don't expect to continue execution, so calling
something that e.g. sets errno is the least of our problems.

A similar patch should be applied to lib/Support/Windows/Signals.inc, but that
can be done separately.

Fix r332428 which I reverted in r332429. I originally used double-wide CAS
because I was lazy, but some platforms use a runtime function for that which
thankfully failed to link (it would have been bad for signal handlers
otherwise). I use a separate flag to guard the data instead.

<rdar://problem/28010281>

Reviewers: dexonsmith

Subscribers: steven_wu, llvm-commits
llvm-svn: 332496

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Revert "Signal handling should be signal-safe"

Some bots don't have double-pointer width compare-and-exchange. Revert for now.q

llvm-svn: 332429

Signal handling should be signal-safe

Summary:
Before this patch, signal handling wasn't signal safe. This leads to real-world
crashes. It used ManagedStatic inside of signals, this can allocate and

Signal handling should be signal-safe

Summary:
Before this patch, signal handling wasn't signal safe. This leads to real-world
crashes. It used ManagedStatic inside of signals, this can allocate and can lead
to unexpected state when a signal occurs during llvm_shutdown (because
llvm_shutdown destroys the ManagedStatic). It also used cl::opt without custom
backing storage. Some de-allocation was performed as well. Acquiring a lock in a
signal handler is also a great way to deadlock.

We can't just disable signals on llvm_shutdown because the signals might do
useful work during that shutdown. We also can't just disable llvm_shutdown for
programs (instead of library uses of clang) because we'd have to then mark the
pointers as not leaked and make sure all the ManagedStatic uses are OK to leak
and remain so.

Move all of the code to lock-free datastructures instead, and avoid having any
of them in an inconsistent state. I'm not trying to be fancy, I'm not using any
explicit memory order because this code isn't hot. The only purpose of the
atomics is to guarantee that a signal firing on the same or a different thread
doesn't see an inconsistent state and crash. In some cases we might miss some
state (for example, we might fail to delete a temporary file), but that's fine.

Note that I haven't touched any of the backtrace support despite it not
technically being totally signal-safe. When that code is called we know
something bad is up and we don't expect to continue execution, so calling
something that e.g. sets errno is the least of our problems.

A similar patch should be applied to lib/Support/Windows/Signals.inc, but that
can be done separately.

<rdar://problem/28010281>

Reviewers: dexonsmith

Subscribers: aheejin, llvm-commits

Differential Revision: https://reviews.llvm.org/D46858

llvm-svn: 332428

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Simplify LLVM_ATTRIBUTE_USED call sites.

llvm-svn: 331599

IWYU for llvm-config.h in llvm, additions.

See r331124 for how I made a list of files missing the include.
I then ran this Python script:

for f in open('filelist.txt'):
f = f.strip()

IWYU for llvm-config.h in llvm, additions.

See r331124 for how I made a list of files missing the include.
I then ran this Python script:

for f in open('filelist.txt'):
f = f.strip()
fl = open(f).readlines()

found = False
for i in xrange(len(fl)):
p = '#include "llvm/'
if not fl[i].startswith(p):
continue
if fl[i][len(p):] > 'Config':
fl.insert(i, '#include "llvm/Config/llvm-config.h"\n')
found = True
break
if not found:
print 'not found', f
else:
open(f, 'w').write(''.join(fl))

and then looked through everything with `svn diff | diffstat -l | xargs -n 1000 gvim -p`
and tried to fix include ordering and whatnot.

No intended behavior change.

llvm-svn: 331184

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s/LLVM_ON_WIN32/_WIN32/, llvm

LLVM_ON_WIN32 is set exactly with MSVC and MinGW (but not Cygwin) in
HandleLLVMOptions.cmake, which is where _WIN32 defined too. Just use the
default macro instead of

s/LLVM_ON_WIN32/_WIN32/, llvm

LLVM_ON_WIN32 is set exactly with MSVC and MinGW (but not Cygwin) in
HandleLLVMOptions.cmake, which is where _WIN32 defined too. Just use the
default macro instead of a reinvented one.

See thread "Replacing LLVM_ON_WIN32 with just _WIN32" on llvm-dev and cfe-dev.
No intended behavior change.

This moves over all uses of the macro, but doesn't remove the definition
of it in (llvm-)config.h yet.

llvm-svn: 331127

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Convenience/safety fix for llvm::sys::Execute(And|No)Wait

Summary:
Change the type of the Redirects parameter of llvm::sys::ExecuteAndWait,
ExecuteNoWait and other APIs that wrap them from `const St

Convenience/safety fix for llvm::sys::Execute(And|No)Wait

Summary:
Change the type of the Redirects parameter of llvm::sys::ExecuteAndWait,
ExecuteNoWait and other APIs that wrap them from `const StringRef **` to
`ArrayRef<Optional<StringRef>>`, which is safer and simplifies the use of these
APIs (no more local StringRef variables just to get a pointer to).

Corresponding clang changes will be posted as a separate patch.

Reviewers: bkramer

Reviewed By: bkramer

Subscribers: vsk, llvm-commits

Differential Revision: https://reviews.llvm.org/D37563

llvm-svn: 313155

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bugpoint: disabling symbolication of bugpoint-executed programs

Initial implementation - needs similar work/testing for other tools
bugpoint invokes (llc, lli I think, maybe more).

Alternatively (a

bugpoint: disabling symbolication of bugpoint-executed programs

Initial implementation - needs similar work/testing for other tools
bugpoint invokes (llc, lli I think, maybe more).

Alternatively (as suggested by chandlerc@) an environment variable could
be used. This would allow the option to pass transparently through user
scripts, pass to compilers if they happened to be LLVM-ish, etc.

I worry a bit about using cl::opt in the crash handling code - LLVM
might crash early, perhaps before the cl::opt is properly initialized?
Or at least before arguments have been parsed?

- should be OK since it defaults to "pretty", so if the crash is very
early in opt parsing, etc, then crash reports will still be symbolized.

I shyed away from doing this with an environment variable when I
realized that would require copying the existing environment and
appending the env variable of interest. But it seems there's no existing
LLVM API for accessing the environment (even the Support tests for
process launching have their own ifdefs for getting the environment). It
could be added, but seemed like a higher bar/untested codepath to
actually add environment variables.

Most importantly, this reduces the runtime of test/BugPoint/metadata.ll
in a split-dwarf Debug build from 1m34s to 6.5s by avoiding a lot of
symbolication. (this wasn't a problem for non-split-dwarf builds only
because the executable was too large to map into memory (due to bugpoint
setting a 400MB memory (including address space - not sure why? Going to
remove that) limit on the child process) so symbolication would fail
fast & wouldn't spend all that time parsing DWARF, etc)

Reviewers: chandlerc, dannyb

Differential Revision: https://reviews.llvm.org/D33804

llvm-svn: 305056

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Sort the remaining #include lines in include/... and lib/....

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

Sort the remaining #include lines in include/... and lib/....

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

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Remove name space pollution from Signals.cpp

llvm-svn: 299224

Search for llvm-symbolizer binary in the same directory as argv[0], before
looking for it along $PATH. This allows installs of LLVM tools outside of
$PATH to find the symbolizer and produce pretty ba

Search for llvm-symbolizer binary in the same directory as argv[0], before
looking for it along $PATH. This allows installs of LLVM tools outside of
$PATH to find the symbolizer and produce pretty backtraces if they crash.

llvm-svn: 272232

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Appease hosts without HAVE_BACKTRACE nor ENABLE_BACKTRACES.

llvm/lib/Support/Signals.cpp:66:13: warning: unused function 'printSymbolizedStackTrace' [-Wunused-function]
llvm/lib/Support/Signals.

Appease hosts without HAVE_BACKTRACE nor ENABLE_BACKTRACES.

llvm/lib/Support/Signals.cpp:66:13: warning: unused function 'printSymbolizedStackTrace' [-Wunused-function]
llvm/lib/Support/Signals.cpp:52:13: warning: function 'findModulesAndOffsets' has internal linkage but is not defined [-Wundefined-internal]

llvm-svn: 252418

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[Windows] Symbolize with llvm-symbolizer instead of dbghelp in a self-host

Summary:
llvm-symbolizer understands both PDBs and DWARF, so it is more likely to
succeed at symbolization. If llvm-symboli

[Windows] Symbolize with llvm-symbolizer instead of dbghelp in a self-host

Summary:
llvm-symbolizer understands both PDBs and DWARF, so it is more likely to
succeed at symbolization. If llvm-symbolizer is unavailable, we will
fall back to dbghelp. This also makes our crash traces more similar
between Windows and Linux.

Reviewers: Bigcheese, zturner, chapuni

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12884

llvm-svn: 252118

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Rename RunCallBacksToRun to llvm::sys::RunSignalHandlers

And expose it in Signals.h, allowing clients to call it directly,
possibly LLVMErrorHandler which currently calls RunInterruptHandlers
but no

Rename RunCallBacksToRun to llvm::sys::RunSignalHandlers

And expose it in Signals.h, allowing clients to call it directly,
possibly LLVMErrorHandler which currently calls RunInterruptHandlers
but not RunSignalHandlers, thus for example not printing the stack
backtrace on Unixish OSes. On Windows it does happen because
RunInterruptHandlers ends up calling the callbacks as well via
Cleanup(). This difference in behaviour and code structures in
*/Signals.inc should be patched in the future.

llvm-svn: 242936

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De-duplicate Unix & Windows CallBacksToRun

Move CallBacksToRun into the common Signals.cpp, create RunCallBacksToRun()
and use these in both Unix/Signals.inc and Windows/Signals.inc.

Lots of potent

De-duplicate Unix & Windows CallBacksToRun

Move CallBacksToRun into the common Signals.cpp, create RunCallBacksToRun()
and use these in both Unix/Signals.inc and Windows/Signals.inc.

Lots of potential code to be merged here.

llvm-svn: 242925

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Fix a ton of comment typos found by codespell. Patch by
Luis Felipe Strano Moraes!

llvm-svn: 129558

Merge System into Support.

llvm-svn: 120298

It is not possible to catch SIGKILL, don't bother trying.

llvm-svn: 15496

Signals.h header moved. Eventually this should move into a lib/System library,
but not right now.

llvm-svn: 13811

`cat' is usually in /bin, not /usr/bin, at least on our systems.

llvm-svn: 11690

When printing a stack trace, demangle it if possible. Since we are potentially
in a signal handler, allocating memory or doing other unsafe things is bad,
which means we should do it in a different

When printing a stack trace, demangle it if possible. Since we are potentially
in a signal handler, allocating memory or doing other unsafe things is bad,
which means we should do it in a different process.

llvm-svn: 11689

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Use backtrace() and include execinfo.h, if they were detected by autoconf.

llvm-svn: 11658

Disable the stack trace thing until we can get an autoconf test for it. This
call breaks on sparcs

llvm-svn: 11635