24 Commits

Author SHA1 Message Date
Martin Storsjö
ba9b2cdb9c [libunwind] [SEH] Add debug logging in __libunwind_seh_personality
Differential Revision: https://reviews.llvm.org/D148659
2023-04-19 23:05:48 +03:00
Martin Storsjö
66632e8798 [libunwind] [SEH] Handle ExceptionContinueExecution in forced unwinding
This fixes the libcxxabi test force_unwind3.pass.cpp when run on native
Windows.

When unwinding past the main thread function into the system functions
that brought up the thread, we can hit functions whose personality
functions return ExceptionContinueExecution (instead of the regular
ExceptionContinueSearch). Interpret this as a signal to stop the
unwind.

Curiously, in this case, it does return ExceptionContinueSearch if
running within a debugger.

Differential Revision: https://reviews.llvm.org/D147739
2023-04-11 00:00:30 +03:00
Martin Storsjö
a017aefeac [libunwind] Fix a typo in a debug log message. NFC.
This typo (unw_step instead of unw_get_proc_info) has been around since
the initial public commit of libunwind.

Differential Revision: https://reviews.llvm.org/D147631
2023-04-06 11:07:41 +03:00
Gabriel Ravier
dad00daa7a [libunwind] Fixed a number of typos
I went over the output of the following mess of a command:

`(ulimit -m 2000000; ulimit -v 2000000; git ls-files -z | parallel --xargs -0 cat | aspell list --mode=none --ignore-case | grep -E '^[A-Za-z][a-z]*$' | sort | uniq -c | sort -n | grep -vE '.{25}' | aspell pipe -W3 | grep : | cut -d' ' -f2 | less)`

and proceeded to spend a few days looking at it to find probable typos
and fixed a few hundred of them in all of the llvm project (note, the
ones I found are not anywhere near all of them, but it seems like a
good start).

Reviewed By: #libunwind, MaskRay

Differential Revision: https://reviews.llvm.org/D130948
2022-08-20 18:09:03 -07:00
Martin Storsjö
08d30c602b [libunwind] Don't store a predecremented PC when using SEH
This fixes unwinding in boundary cases on ARM with SEH.

In the case of ARM/Thumb, disp->ControlPc points at the following
instruction, with the thumb bit set. Thus by decrementing 1,
it still points at the next instruction. To achieve the desired
effect of pointing at the previous instruction, one first has to strip
out the thumb bit, then do the decrement by 1 to reach the previous
instruction.

When libcxxabi looks for call site ranges, it already does
`_Unwind_GetIP(context) - 1` (in `scan_eh_tab` in
libcxxabi/src/cxa_personality.cpp), so we shouldn't do the
corresponding `- 1` multiple times.

In the case of libcxxabi on Thumb, `funcStart` (still in `scan_eh_tab`)
may have the thumb bit set. If the program counter address is
decremented both in libunwind (first removing the thumb bit, then
decremented), and then libcxxabi decrements it further, and compares
with a `funcStart` with the thumb bit set, it could point to one byte
before the start of the call site.

Thus: This modification makes libunwind with SEH work with libcxxabi
on Thumb, in settings where libunwind and libcxxabi worked fine with
Dwarf before.

For existing cases with libunwind with SEH (on x86_64 and aarch64),
this modification doesn't break any of my testcases.

Differential Revision: https://reviews.llvm.org/D126869
2022-06-06 23:25:24 +03:00
Martin Storsjö
7c0e93cb89 [libunwind] Fix SEH unwinding on ARM
Check `__SEH__` when checking if ARM EHABI should be implied,
similarly to 4a3722a2c3dff1fe885cc38bf43d3c095c9851e7 / D126866.

Fix a warning by using the right format specifier (PRIxPTR instead
of PRIx64), and add a double->float cast in a codepath that hasn't
been built so far.

This is enough to make SEH unwinding of itanium ABI exceptions on
ARM mostly work - one specific issue is fixed in a separate follow-up
patch.

Differential Revision: https://reviews.llvm.org/D126867
2022-06-06 23:23:35 +03:00
Louis Dionne
eb8650a757 [runtimes][NFC] Remove filenames at the top of the license notice
We've stopped doing it in libc++ for a while now because these names
would end up rotting as we move things around and copy/paste stuff.
This cleans up all the existing files so as to stop the spreading
as people copy-paste headers around.
2021-11-17 16:30:52 -05:00
Fangrui Song
9ae9dd3fcf [libunwind] Add UNW_AARCH64_* beside UNW_ARM64_*
The original libunwind project defines UNW_AARCH64_* instead of UNW_ARM64_*.
Rename the enum members to match. This allows some applications with simple
`unw_init_local` usage to migrate to llvm-project libunwind.

Note: the canonical names of `UNW_ARM_D{0..31}` are now `UNW_AARCH64_V{0..31}`,
to match the original libunwind.

UNW_ARM64_* are kept for now for compatibility. Some may be unneeded and can be
cleaned up in the future.

Reviewed By: #libunwind, compnerd

Differential Revision: https://reviews.llvm.org/D107996
2021-08-20 14:26:27 -07:00
Daniel Kiss
6b6d344731 [libunwind] Compile with -Wunused-but-set-variable
-Wunused-but-set-variable triggers a warning even the block of code is effectively dead.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D107835
2021-08-11 10:15:54 +02:00
Martin Storsjö
fc5e68fab9 [libunwind] [SEH] Don't interact with foreign exceptions
This unfortunately means that we don't execute C++ destructors when
unwinding past such frames for a different SEH unwind purpose (e.g.
as part of setjmp/longjmp), but that case isn't handled properly at
the moment (the original unwind intent is lost and we end up with an
unhandled exception). This patch makes sure the foreign unwind terminates
as intended.

After executing a handler, _Unwind_Resume doesn't have access to
the target frame parameter of the original foreign unwind. We also
currently blindly set ExceptionCode to STATUS_GCC_THROW - we could
set that correctly by storing the original code in _GCC_specific_handler,
but we don't have access to the original target frame value.

This also matches what libgcc's SEH unwinding code does in this case.

Differential Revision: https://reviews.llvm.org/D89231
2020-10-12 23:28:22 +03:00
Saleem Abdulrasool
14798b4465 unwind: rename __personality_routine to _Unwind_Personality_Fn
This patch renames `__personality_routine` to `_Unwind_Personality_Fn`
in `unwind.h`. Both `unwind.h` from clang and GCC headers use this name
instead of `__personality_routine`. With this patch one is also able to
build libc++abi with libunwind support on Windows.

Patch by Markus Böck!
2020-02-10 08:52:31 -08:00
Petr Hosek
e369a989fc [libunwind] Export the unw_* symbols as weak symbols
libunwind defines the _Unwind_* ABI used by libc++abi. This ABI is a
stable quasi-standard common between multiple implementations such as
LLVM and GNU. The _U* symbol name space is also safely within the symbol
name space that standard C & C++ reserve for the implementation.

Futhermore, libunwind also defines several unw_* symbols, and references
these from the _Unwind_* entry points so the standard/reserved part of
the ABI is dependent on the unw_* part of the ABI. This is not OK for a
C or C++ implementation. The unw_* symbols are reserved for C and extern
"C" used by application code.

This change renames each unw_* function to __unw* and adds a weak alias
unw_* to keep the public <libunwind.h> ABI unchanged for backwards
compatibility. Every reference to unw_* in the implementation has been
changed to use __unw* so that if other unw_* definitions are in force
because nothing uses <libunwind.h> in a particular program, no _Unwind*
code path depends on any unw_* symbol. Furthemore, __unw_* symbols are
hidden, which saves PLT overhead in the shared library case.

In the future, we should cconsider untangling the unw_* API/ABI from the
_Unwind_* API/ABI. The internal API backing the _Unwind_* ABI
implementation should not rely on any nonstandard symbols not in the
implementation-reserved name space. This would then allow separating the
_Unwind_* API/ABI from unw_* entirely, but that's a more substantial
change that's going to require more significant refactoring.

Differential Revision: https://reviews.llvm.org/D59921

llvm-svn: 357640
2019-04-03 21:50:03 +00:00
Petr Hosek
5745e90800 [libunwind] Provide placement new definition
While Clang automatically generates the code for placement new,
g++ doesn't do that so we need to provide our own definition.

Differential Revision: https://reviews.llvm.org/D57455

llvm-svn: 352966
2019-02-02 21:15:49 +00:00
Petr Hosek
7fac51724f Drop the dependency on <algorithm>, add placement new inline
We haven't eliminated C++ library dependency altogether in D57251,
UnwindCursor.hpp had an unused dependency on <algorithm> which was
pulling in other C++ headers. Removing that dependency also revealed
(correctly) that we need our own global placement new declaration. Now
libunwind should be independent of the C++ library.

Differential Revision: https://reviews.llvm.org/D57262

llvm-svn: 352553
2019-01-29 22:26:18 +00:00
Petr Hosek
4ecdb70424 Revert "[libunwind] Drop the dependency on <algorithm>, add placement new inline"
This reverts commit r352384: this broke on ARM as UnwindCursor.hpp
still has some C++ library dependencies.

llvm-svn: 352427
2019-01-28 20:55:12 +00:00
Petr Hosek
91a606e6c4 [libunwind] Drop the dependency on <algorithm>, add placement new inline
We haven't eliminated C++ library dependency altogether in D57251,
UnwindCursor.hpp had an unused dependency on <algorithm> which was
pulling in other C++ headers. Removing that dependency also revealed
(correctly) that we need our own global placement new declaration. Now
libunwind should be independent of the C++ library.

Differential Revision: https://reviews.llvm.org/D57262

llvm-svn: 352384
2019-01-28 16:44:56 +00:00
Martin Storsjo
ea5702481a Silence warnings about unused parameters
Differential Revision: https://reviews.llvm.org/D56984

llvm-svn: 351888
2019-01-22 22:12:23 +00:00
Martin Storsjo
4540f5d82e Remove an unused variable
Differential Revision: https://reviews.llvm.org/D56985

llvm-svn: 351878
2019-01-22 20:50:45 +00:00
Martin Storsjo
94adf435ca Fix warnings about printf format strings
Either adjust the format string to use a more exact type, or add casts
(for cases when printing pointers to structs/objects with a %p
format specifier).

Differential Revision: https://reviews.llvm.org/D56982

llvm-svn: 351876
2019-01-22 20:50:39 +00:00
Chandler Carruth
57b08b0944 Update more file headers across all of the LLVM projects in the monorepo
to reflect the new license. These used slightly different spellings that
defeated my regular expressions.

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: 351648
2019-01-19 10:56:40 +00:00
Martin Storsjo
09cf6374c1 [SEH] Add initial support for AArch64
This doesn't yet implement inspecting the .pdata/.xdata to find the
LSDA pointer (in UnwindCursor::getInfoFromSEH), but normal C++
exception handling seems to run just fine without it. (The only
place I can see where it's even referenced is in
unwind_phase2_forced, and I can't find a codepath where libcxxabi
would end up calling that.)

Differential Revision: https://reviews.llvm.org/D55674

llvm-svn: 349532
2018-12-18 20:05:59 +00:00
Martin Storsjo
4862ff8d17 [SEH] Zero-initialize EXCEPTION_RECORD and UNWIND_HISTORY_TABLE before calling RtlUnwindEx
This fixes PR39935.

llvm-svn: 348836
2018-12-11 09:53:11 +00:00
Martin Storsjo
a2646444d2 Fix existing code for SEH on ARM to compile correctly
Even though SEH for ARM is incomplete, make what code already exists
at least compile correctly.

The _LIBUNWIND_CURSOR_SIZE wasn't correct.

ARM (and AArch64) have a DISPATCHER_CONTEXT field named TargetPc
instead of TargetIp.

For the libunwind.h UNW_* constants, there is no UNW_ARM_PC, only
UNW_ARM_IP.

Don't use 'r' as loop variable when 'r' already is a Registers_arm
member.

Differential Revision: https://reviews.llvm.org/D51530

llvm-svn: 341217
2018-08-31 14:56:55 +00:00
Charles Davis
a7e3a6d802 Add support for SEH unwinding on Windows.
Summary:
I've tested this implementation on x86-64 to ensure that it works. All
`libc++abi` tests pass, as do all `libc++` exception-related tests. ARM
still remains to be implemented (@compnerd?).

Special thanks to KJK::Hyperion for his excellent series of articles on
how EH works on x86-64 Windows. (Seriously, check it out. It's awesome.)

I'm actually not sure if this should go in as is. I particularly don't
like that I duplicated the UnwindCursor class for this special case.

Reviewers: mstorsjo, rnk, compnerd, smeenai, javed.absar

Subscribers: mgorny, kristof.beyls, christof, chrib, cfe-commits, compnerd, llvm-commits

Differential Revision: https://reviews.llvm.org/D50564

llvm-svn: 341125
2018-08-30 21:29:00 +00:00