Commit Graph

69 Commits

Author SHA1 Message Date
Louis Dionne 395271ad11 [runtimes] Simplify how we set the target triple
Instead of using TARGET_TRIPLE, which is always set to LLVM_DEFAULT_TARGET_TRIPLE,
use that variable directly to populate the various XXXX_TARGET_TRIPLE
variables in the runtimes.

This re-applies 77396bbc98 and 5099e01568, which were reverted in
850b57c5fb because they broke the build.

Differential Revision: https://reviews.llvm.org/D106009
2021-07-16 10:33:39 -04:00
Louis Dionne 0c3401c86e [runtimes] Serialize all Lit params instead of passing them to add_lit_testsuite
add_lit_testsuite() takes Lit parameters passed to it and adds them
to the parameters used globally when running all test suites. That
means that a target like `check-all`, which ends up calling Lit on
the whole monorepo, will see the test parameters for all the individual
project's test suites.

So, for example, it would see `--param std=c++03` (from libc++abi), and
`--param std=c++03` (from libc++), and `--param whatever` (from another
project being tested at the same time). While always unclean, that works
when the parameters all agree. However, if the parameters share the same
name but have different values, only one of those two values will be used
and it will be incredibly confusing to understand why one of the test
suites is being run with the incorrect parameter value.

For that reason, this commit moves away from using add_lit_testsuite()'s
PARAM functionality, and serializes the parameter values for the runtimes
in the generated config.py file instead, which is local to the specific
test suite.

Differential Revision: https://reviews.llvm.org/D105991
2021-07-15 07:53:15 -04:00
Louis Dionne 850b57c5fb [runtimes] Bring back TARGET_TRIPLE
This commit reverts 5099e01568 and 77396bbc98, which broke the build
in various ways. I'm reverting until I can investigate, since that
change appears to be way more subtle than it seemed.
2021-07-14 15:15:22 -04:00
Louis Dionne 77396bbc98 [runtimes] NFCI: Drop intermediate CMake variable TARGET_TRIPLE
We might as well use the various XXX_TARGET_TRIPLE variables directly.
2021-07-14 10:49:28 -04:00
Louis Dionne f7d8754312 [runtimes] Move enable_32bit to the DSL
This is necessary for from-scratch configurations to support the 32-bit
mode of the test suite.

Differential Revision: https://reviews.llvm.org/D105435
2021-07-06 08:42:07 -04:00
Louis Dionne c360553c15 [runtimes] Simplify how we specify XFAIL & friends based on the triple
Now that Lit supports regular expressions inside XFAIL & friends, it is
much easier to write Lit annotations based on the triple.

Differential Revision: https://reviews.llvm.org/D104747
2021-07-01 14:03:30 -04:00
Louis Dionne 58a230455b [libc++] Serialize Lit parameters to make them available to from-scratch configs
Before this patch, Lit parameters that were set as a result of CMake
options were not made available to from-scratch configs. This patch
serializes those parameters into the generated lit config file so that
they are available to all configs.

Differential Revision: https://reviews.llvm.org/D105047
2021-06-29 10:51:42 -04:00
Amilendra Kodithuwakku 5636402bc0 [libcxx] Fix exception raised during downstream bare-metal libunwind tests
Fix for the following exception.

AttributeError: 'TestingConfig' object has no attribute 'target_triple'

Related revision: https://reviews.llvm.org/D102012

'TestingConfig' object has no attribute 'target_triple'

Reviewed By: #libunwind, miyuki, danielkiss, mstorsjo

Differential Revision: https://reviews.llvm.org/D103140
2021-06-16 13:35:36 +01:00
Louis Dionne 875ff8e059 [libc++] Enable tests for the experimental library by default
This matches the fact that we build the experimental library by default.
Otherwise, by default we'd be building the library but not testing it,
which is inconsistent.

Differential Revision: https://reviews.llvm.org/D102109
2021-06-02 18:39:27 -04:00
Louis Dionne 74d096e558 [libc++] Move handling of the target triple to the DSL
This fixes a long standing issue where the triple is not always set
consistently in all configurations. This change also moves the
back-deployment Lit features to using the proper target triple
instead of using something ad-hoc.

This will be necessary for using from scratch Lit configuration files
in both normal testing and back-deployment testing.

Differential Revision: https://reviews.llvm.org/D102012
2021-05-08 11:10:53 -04:00
Louis Dionne c06a8f9caa [libc++] Include <__config_site> from <__config>
Prior to this patch, we would generate a fancy <__config> header by
concatenating <__config_site> and <__config>. This complexifies the
build system and also increases the difference between what's tested
and what's actually installed.

This patch removes that complexity and instead simply installs <__config_site>
alongside the libc++ headers. <__config_site> is then included by <__config>,
which is much simpler. Doing this also opens the door to having different
<__config_site> headers depending on the target, which was impossible before.

It does change the workflow for testing header-only changes to libc++.
Previously, we would run `lit` against the headers in libcxx/include.
After this patch, we run it against a fake installation root of the
headers (containing a proper <__config_site> header). This makes use
closer to testing what we actually install, which is good, however it
does mean that we have to update that root before testing header changes.
Thus, we now need to run `ninja check-cxx-deps` before running `lit` by
hand.

Differential Revision: https://reviews.llvm.org/D97572
2021-03-30 14:06:11 -07:00
Louis Dionne 60ba1fefab [libc++/abi] Allow running back-deployment testing against libc++abi
Before this patch, we could only link against the back-deployment libc++abi
dylib. This patch allows linking against the just-built libc++abi, but
running against the back-deployment one -- just like we do for libc++.

Also, add XFAIL markup to flag expected errors.

Differential Revision: https://reviews.llvm.org/D91069
2021-03-01 12:13:03 -05:00
Ryan Prichard c82deed676 [libunwind] Unwind through aarch64/Linux sigreturn frame
An AArch64 sigreturn trampoline frame can't currently be described
in a DWARF .eh_frame section, because the AArch64 DWARF spec currently
doesn't define a constant for the PC register. (PC and LR may need to
be restored to different values.)

Instead, use the same technique as libgcc or github.com/libunwind and
detect the sigreturn frame by looking for the sigreturn instructions:

    mov x8, #0x8b
    svc #0x0

If a sigreturn frame is detected, libunwind restores all the GPRs by
assuming that sp points at an rt_sigframe Linux kernel struct. This
behavior is a fallback mode that is only used if there is no ordinary
unwind info for sigreturn.

If libunwind can't find unwind info for a PC, it assumes that the PC is
readable, and would crash if it isn't. This could happen if:
 - The PC points at a function compiled without unwind info, and which
   is part of an execute-only mapping (e.g. using -Wl,--execute-only).
 - The PC is invalid and happens to point to unreadable or unmapped
   memory.

In the tests, ignore a failed dladdr call so that the tests can run on
user-mode qemu for AArch64, which uses a stack-allocated trampoline
instead of a vDSO.

Reviewed By: danielkiss, compnerd, #libunwind

Differential Revision: https://reviews.llvm.org/D90898
2021-01-13 16:38:36 -08:00
Louis Dionne c1887e3f15 Revert "Allow running back-deployment testing against libc++abi"
This reverts commit 4d79ef814a, which broke a few build bots.
I'm reverting until I have time to investigate.
2020-11-06 17:26:42 -05:00
Louis Dionne 4d79ef814a Allow running back-deployment testing against libc++abi
Summary:
Before this patch, we could only link against the back-deployment libc++abi
dylib. This patch allows linking against the just-built libc++abi, but
running against the back-deployment one -- just like we do for libc++.

Also, add XFAIL markup to flag expected errors.
2020-11-06 08:12:46 -05:00
Daniel Kiss 05598e3d30 [libunwind] Fix linker flag handling in the tests.
--export-dynamic is not always available on all targets.
-funwind-tables was a duplicate in the lit.site.cfg.in.

Reviewed By: ldionne

Differential Revision: https://reviews.llvm.org/D90202
2020-10-29 14:02:44 +01:00
Louis Dionne 48e4b0fd3a [runtimes] Revert the libc++ __config_site change
This is a massive revert of the following commits (from most revent to oldest):

	2b9b7b5775.
	529ac33197
	28270234f1
	69c2087283
	b5aa67446e
	5d796645d6

After checking-in the __config_site change, a lot of things started breaking
due to widespread reliance on various aspects of libc++'s build, notably the
fact that we can include the headers from the source tree, but also reliance
on various "internal" CMake variables used by the runtimes build and compiler-rt.

These were unintended consequences of the change, and after two days, we
still haven't restored all the bots to being green. Instead, now that I
understand what specific areas this will blow up in, I should be able to
chop up the patch into smaller ones that are easier to digest.

See https://reviews.llvm.org/D89041 for more details on this adventure.
2020-10-23 09:41:48 -04:00
Louis Dionne 5d796645d6 [take 2] [libc++] Include <__config_site> from <__config>
Prior to this patch, we would generate a fancy <__config> header by
concatenating <__config_site> and <__config>. This complexifies the
build system and also increases the difference between what's tested
and what's actually installed.

This patch removes that complexity and instead simply installs <__config_site>
alongside the libc++ headers. <__config_site> is then included by <__config>,
which is much simpler. Doing this also opens the door to having different
<__config_site> headers depending on the target, which was impossible before.

It does change the workflow for testing header-only changes to libc++.
Previously, we would run `lit` against the headers in libcxx/include.
After this patch, we run it against a fake installation root of the
headers (containing a proper <__config_site> header). This makes use
closer to testing what we actually install, which is good, however it
does mean that we have to update that root before testing header changes.
Thus, we now need to run `ninja check-cxx-deps` before running `lit` by
hand.

This commit was originally applied in 1e46d1aa3 and reverted in eb60c487
because it broke the libc++abi and libunwind test suites. This has now
been fixed.

Differential Revision: https://reviews.llvm.org/D89041
2020-10-21 10:40:33 -04:00
Dominik Montada 8c03fdf34a [libcxxabi,libunwind] support running tests in standalone mode
Remove check for standalone and shared library mode in libcxxabi to
allow including tests in said mode. This check prevented running the
tests in standalone mode with static libraries, which is the case for
baremetal targets.

Fix check-unwind target trying to use a non-existent llvm-lit executable
in standalone mode. Copy the HandleOutOfTreeLLVM logic from libcxxabi to
libunwind in order to make the tests work in standalone mode.

Reviewed By: ldionne, #libc_abi, #libc

Differential Revision: https://reviews.llvm.org/D86540
2020-10-14 09:10:20 +02:00
Louis Dionne 504bc07d1a [runtimes] Use int main(int, char**) consistently in tests
This is needed when running the tests in Freestanding mode, where main()
isn't treated specially. In Freestanding, main() doesn't get mangled as
extern "C", so whatever runtime we're using fails to find the entry point.

One way to solve this problem is to define a symbol alias from __Z4mainiPPc
to _main, however this requires all definitions of main() to have the same
mangling. Hence this commit.
2020-10-08 14:28:13 -04:00
Ryan Prichard b16d6653c0 [libunwind] Combine dl_iterate_phdr codepaths for DWARF and EHABI
dl_iterate_phdr is used to search for unwind info provided by either
PT_GNU_EH_FRAME or PT_ARM_EXIDX. Most of the code between the two is
the same, so combine them, and factor out what's different into
checkForUnwindInfoSegment.

Details:
 - The FrameHeaderCache can now be enabled for ARM EHABI.
 - findUnwindSectionsByPhdr now finds the last PT_ARM_EXIDX rather than
   the first. There should only be one segment.
 - The dso_base and text_segment_length fields of UnwindInfoSections
   are now needed for dl_iterate_phdr when using EHABI, to hold the
   low and high PC values for a cache entry.

Reviewed By: compnerd, danielkiss, #libunwind, saugustine

Differential Revision: https://reviews.llvm.org/D87880
2020-09-23 15:40:39 -07:00
Daniel Kiss 22b615a965 [libunwind] Support for leaf function unwinding.
Unwinding leaf function is useful in cases when the backtrace finds a
leaf function for example when it caused a signal.
This patch also add the support for the DW_CFA_undefined because it marks
the end of the frames.

Ryan Prichard provided code for the tests.

Reviewed By: #libunwind, mstorsjo

Differential Revision: https://reviews.llvm.org/D83573

Reland with limit the test to the x86_64-linux target.
2020-09-18 15:09:42 +02:00
Daniel Kiss 5831adb8c3 Revert "[libunwind] Support for leaf function unwinding."
This reverts commit 23bef7ee99.
2020-09-18 11:37:54 +02:00
Ryan Prichard fb1abe0063 [libunwind][DWARF] Fix end of .eh_frame calculation
* When .eh_frame is located using .eh_frame_hdr (PT_GNU_EH_FRAME), the
   start of .eh_frame is known, but not the size. In this case, the
   unwinder must rely on a terminator present at the end of .eh_frame.
   Set dwarf_section_length to UINTPTR_MAX to indicate this.

 * Add a new field, text_segment_length, that the FrameHeaderCache uses
   to track the size of the PT_LOAD segment indicated by dso_base.

 * Compute ehSectionEnd by adding sectionLength to ehSectionStart,
   never to fdeHint.

Fixes PR46829.

Differential Revision: https://reviews.llvm.org/D87750
2020-09-16 19:00:57 -07:00
Daniel Kiss 23bef7ee99 [libunwind] Support for leaf function unwinding.
Unwinding leaf function is useful in cases when the backtrace finds a
leaf function for example when it caused a signal.
This patch also add the support for the DW_CFA_undefined because it marks
the end of the frames.

Ryan Prichard provided code for the tests.

Reviewed By: #libunwind, mstorsjo

Differential Revision: https://reviews.llvm.org/D83573
2020-09-16 23:53:36 +02:00
Louis Dionne ec46cfefe8 [libcxx] Simplify back-deployment testing
The needs of back-deployment testing currently require two different
ways of running the test suite: one based on the deployment target,
and one based on the target triple. Since the triple includes all the
information we need, it's better to have just one way of doing things.

Furthermore, `--param platform=XXX` is also supersedded by using the
target triple. Previously, this parameter would serve the purpose of
controling XFAILs for availability markup errors, however it is possible
to achieve the same thing by using with_system_cxx_lib only and using
.verify.cpp tests instead, as explained in the documentation changes.

The motivation for this change is twofold:
1. This part of the Lit config has always been really confusing and
   complicated, and it has been a source of bugs in the past. I have
   simplified it iteratively in the past, but the complexity is still
   there.
2. The deployment-target detection started failing in weird ways in
   recent Clangs, breaking our CI. Instead of band-aid patching the
   issue, I decided to remove the complexity altogether by using target
   triples even on Apple platforms.

A follow-up to this commit will bring the test suite in line with
the recommended way of handling availability markup tests.
2020-09-10 08:17:26 -04:00
Ryan Prichard 88bf133c99 [libunwind] Replace chain-of-ifdefs for dl_iterate_phdr
Define a _LIBUNWIND_USE_DL_ITERATE_PHDR macro in config.h when there is
no other unwind info lookup method. Also define a
_LIBUNWIND_USE_DL_UNWIND_FIND_EXIDX macro to factor out
(__BIONIC__ and _LIBUNWIND_ARM_EHABI).

Differential Revision: https://reviews.llvm.org/D86768
2020-09-08 15:49:35 -07:00
Sterling Augustine a20f5fe708 Default to disabling the libunwind frameheader cache.
Although it works fine with glibc, as currently implemented the
frameheader cache is incompatible with certain platforms with
slightly different locking semantics inside dl_iterate_phdr.

Therefore only enable it when it is turned on explicitly with
a configure-time option.

Differential Revision: https://reviews.llvm.org/D86163
2020-08-18 14:37:36 -07:00
Daniel Kiss 9c3f6fb688 [libunwind] Make the test depend on the libunwind explicitly.
Before this patch the `ninja check-unwind` won't rebuild the unwind library.

Reviewed By: jroelofs

Differential Revision: https://reviews.llvm.org/D85004
2020-08-03 09:46:23 +02:00
Louis Dionne ff0d4367bf [runtimes] Move the enable_rtti Lit parameter to the DSL 2020-07-16 12:56:00 -04:00
Louis Dionne 0f03626fbf [runtimes][NFC] Remove unused or unnecessary CMake variables 2020-07-16 10:47:08 -04:00
Louis Dionne 70f6389257 [runtimes] Rename newformat to just format, now that the old format has been removed 2020-06-30 10:10:30 -04:00
Louis Dionne 5d83880885 [runtimes] Remove the ability to select the old libc++ testing format
As announced on libcxx-dev at [1], the old libc++ testing format is being
removed in favour of the new one. Follow-up commits will clean up the
code that is dead after the removal of this option.

[1]: http://lists.llvm.org/pipermail/libcxx-dev/2020-June/000885.html
2020-06-29 14:07:41 -04:00
Louis Dionne c55051eea5 [libunwind] Allow specifying custom Lit config files
This is the libunwind counterpart of 0c66af970c.
2020-06-25 12:15:15 -04:00
Louis Dionne 96e6cbbf94 [libc++] Allow specifying arbitrary custom executors with the new format
The integration between CMake and executor selection in the new format
wasn't very flexible -- only the default executor and SSH executors were
supported.

This patch makes it possible to specify arbitrary executors with the new
format. With the new testing format, a custom executor is just a script
that gets called with a command-line to execute, and some arguments like
--env, --codesign_identity and --execdir. As such, the default executor
is just run.py.

Remote execution with the SSH executor can be achived by specifying
LIBCXX_EXECUTOR="<path-to-ssh.py> --host <host>". Similarly, arbitrary
scripts can be provided.
2020-06-11 16:24:29 -04:00
Louis Dionne 168681abce [libc++abi][libunwind] Don't override libc++'s handling of exception features
0e04342ae0 simplified exceptions-related configurations for libc++abi
and libunwind by reusing the logic in libc++. However, it missed the fact
that libc++abi and libunwind were overriding libc++'s handling of exceptions.

This commit removes special handling in libc++abi and libunwind to use
the logic in libc++, which is the right one.
2020-06-09 16:03:22 -04:00
Louis Dionne 0e04342ae0 [NFCI] Clean up exceptions related CMake and Lit options in libc++abi and libunwind
First, libc++abi doesn't need to add the no-exceptions Lit feature itself,
since that is already done in the config.py for libc++, which it reuses.
Specifically, config.enable_exceptions is set based on @LIBCXXABI_ENABLE_EXCEPTIONS@
in libc++abi's lit.cfg.in, and libc++'s config.py handles that correctly.

Secondly, libunwind's LIBUNWIND_ENABLE_EXCEPTIONS is never set (it's
probably a remnant of copy-pasting code between the runtime libraries),
so the library is always built with exceptions disabled (which makes
sense since it implements the runtime support for exceptions).
Conversely, the test suite is always run with exceptions enabled
(not sure why), but that is preserved by the default behavior of
libc++'s config.py.
2020-06-09 15:34:29 -04:00
Louis Dionne 8c61114c53 [libc++/abi/unwind] Rename Lit features for no exceptions to 'no-exceptions'
Instead of having different names for the same Lit feature accross code
bases, use the same name everywhere. This NFC commit is in preparation
for a refactor where all three projects will be using the same Lit
feature detection logic, and hence it won't be convenient to use
different names for the feature.

Differential Revision: https://reviews.llvm.org/D78370
2020-04-22 08:25:27 -04:00
Louis Dionne 5f7a030162 [libunwind] Enable the new libc++ testing format by default
The new format should be equivalent to the old format, and it is now the
default format when running the libc++ and libc++abi tests. This commit
changes the libunwind tests to use the new format by default too. If
unexpected failures are discovered, it should be fine to revert this
commit until they are addressed.

Also note that it is still possible to use the old format by passing
`--param=use_old_format=True` when running Lit for the time being.

Differential Revision: https://reviews.llvm.org/D77733
2020-04-13 18:17:18 -04:00
Louis Dionne 6f1d558db4 [libunwind] Fix incorrect lit substitutions in tests
The LIT substitutions used in libunwind are the same as those from
libc++, and we forgot to update the libunwind tests after the libc++
substitutions started being delimited by braces.
2020-04-08 10:50:09 -04:00
Sergej Jaskiewicz 649f042802 [libunwind] Support the new libc++ test format
Reviewers: ldionne, #libunwind, mstorsjo

Reviewed By: ldionne, #libunwind, mstorsjo

Subscribers: mstorsjo, dexonsmith, llvm-commits, libcxx-commits

Tags: #llvm, #libunwind

Differential Revision: https://reviews.llvm.org/D77501
2020-04-06 23:26:59 +03:00
Sterling Augustine 3758b858ef Only run frameheader_cache_test.pass.cpp on x86_64.
Although there is nothing architecturally specific, the
ifdef chains are too complicated otherwise.
2020-03-12 18:14:22 -07:00
Sterling Augustine 3eef58991b Add a catch-all else case so any unanticipated configs pass this test. 2020-03-12 11:55:10 -07:00
Sterling Augustine c53c2058ff Cache uwnind frame headers as they are found.
Summary:
This improves unwind performance quite substantially, and follows
a somewhat similar approach used in libgcc_s as described in the
thread here:

https://gcc.gnu.org/ml/gcc/2005-02/msg00625.html

On certain extremely exception heavy internal tests, the time
drops from about 80 minutes to about five minutes.

Subscribers: libcxx-commits

Tags: #libc

Differential Revision: https://reviews.llvm.org/D75954
2020-03-12 10:53:33 -07:00
Jorge Gorbe Moya 1ae8d81147 [libunwind] Fix memory leak in handling of DW_CFA_remember_state and DW_CFA_restore_state
parseInstructions() doesn't always process the whole set of DWARF
instructions for a frame. It will stop once the target PC is reached, or
if malformed instructions are found. So, for example, if we have an
instruction sequence like this:

```
<start>
...
DW_CFA_remember_state
...
DW_CFA_advance_loc past the location we're unwinding at (pcoffset in parseInstructions() main loop)
...
DW_CFA_restore_state
<end>
```

... the saved state will never be freed, even though the
DW_CFA_remember_state opcode has a matching DW_CFA_restore_state later
in the sequence.

This change adds code to free whatever is left on rememberStack after
parsing the CIE and the FDE instructions.

Differential Revision: https://reviews.llvm.org/D66904
2020-02-18 11:57:18 -08:00
Sergej Jaskiewicz 57fc8ecdba Reland "Enable `-funwind-tables` flag when building libunwind"
Summary:
Relands https://reviews.llvm.org/D70815.

The original commit set `CMAKE_TRY_COMPILE_TARGET_TYPE` to
`STATIC_LIBRARY` globally in libunwind/CMakeLists.txt, which effectively
disabled the linking step in CMake checks.

This broke some builds (see 938c70b86c).

Here we set CMAKE_TRY_COMPILE_TARGET_TYPE to
STATIC_LIBRARY only when checking for presence of the `-funwind-tables`
flag, and then set it back to the original value so it doesn't affect
other checks.

Reviewers: mstorsjo, jfb

Subscribers: mgorny, christof, libcxx-commits

Tags: #libc

Differential Revision: https://reviews.llvm.org/D71117
2019-12-11 04:27:04 +03:00
Martin Storsjö 938c70b86c Revert "Enable `-funwind-tables` flag when building libunwind"
This reverts commit b3fdf33ba6.

This change broke building libunwind for Windows/MinGW, and broke
on aspect of the CMake tests in libunwind in general.

After set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY), CMake
skips the linking step in tests, but cmake/config-ix.cmake also
does a few checks for functions in libraries (looking for whether
-lc provides fopen and whether -ldl provides dladdr).

As CMake only tests building a static library, these tests
incorrectly succeed and CMake concludes "Looking for fopen in c -
found" and "Looking for dladdr in dl - found", while building
then fails at the end with errors about unable to find -lc and -ldl.
2019-12-04 09:29:15 +02:00
Sergej Jaskiewicz b3fdf33ba6 Enable `-funwind-tables` flag when building libunwind
Summary:
Or, rather, don't accidentally forget to pass it.

This is aimed to solve the problem discussed in [this thread](http://lists.llvm.org/pipermail/llvm-dev/2019-November/136890.html), and to fix [a year-old bug](https://bugs.llvm.org/show_bug.cgi?id=38468).

TL;DR: when building libunwind for ARM Linux, we **need** libunwind to be built with the `-funwind-tables` flag, because, well ARM EHABI needs unwind info produced by this flag. Without the flag all the procedures in libunwind are marked `.cantunwind`, which causes all sorts of bad things. From `_Unwind_Backtrace` not working, to C++ exceptions not being caught (which is the aforementioned bug is about).

Previously, this flag was not added because the CMake check `add_compile_flags_if_supported(-funwind-tables)` produced a false negative. Why? With this flag, the compiler generates calls to the `__aeabi_unwind_cpp_pr0` symbol, which is defined in libunwind itself and obviously is not available at configure time, before libunwind is built. This led to failure at link time during the CMake check. We handle this by disabling the linker for CMake checks in linbunwind.

Also, this patch introduces a lit feature `libunwind-arm-ehabi`, which is used to mark the `signal_frame.pass.cpp` test as unsupported (as was advised by @miyuki in D70397).

Reviewers: peter.smith, phosek, EricWF, compnerd, jroelofs, saugustine, miyuki, jfb

Subscribers: mgorny, kristof.beyls, christof, libcxx-commits, miyuki

Tags: #libc

Differential Revision: https://reviews.llvm.org/D70815
2019-12-04 00:52:19 +03:00
Mikhail Maltsev 4fb8ecdef4 [libunwind] Adjust the signal_frame test for Arm
Summary:
This patch adjusts the signal_frame.pass.cpp to pass on Arm targets:
* When Arm EHABI is used the unwinder does not use DWARF, hence the
  DWARF-specific check unw_is_signal_frame() must be disabled.
* Certain C libraries don't include EH tables, so the unwinder must
  not try to step out of main(). The patch moves the test code out of
  main() into a separate function to avoid this.

Reviewers: saugustine, ostannard, phosek, jfb, mclow.lists

Reviewed By: saugustine

Subscribers: dexonsmith, aprantl, kristof.beyls, christof, libcxx-commits, pbarrio, labrinea

Tags: #libc

Differential Revision: https://reviews.llvm.org/D70397
2019-11-19 09:58:46 +00:00
Sterling Augustine d3c744313c Correctly update isSignalFrame when unwinding the stack via dwarf.
A "signal frame" is a function or block of code where execution arrives via a signal or interrupt, rather than via a normal call instruction. In fact, a particular instruction is interrupted by the signal and needs to be restarted. Therefore, when the signal handler is complete, execution needs to return to the interrupted instruction, rather than the instruction immediately following the call instruction, as in a normal call.

Stack unwinders need to know this to correctly unwind signal frames. Dwarf handily provides an "S" in the CIE augmentation string to describe this case, and the libunwind API provides various functions to for unwinders to determine it,.

The llvm libunwind implementation correctly sets it's internal variable "isSignalFrame" when initializing an unwind context. However, upon stepping up the stack, the current implementation correctly reads the augmentation string and sets it in the CIE info (which it then discards), libunwind doesn't update it's internal unwind context data structure.

This change fixes that, and provides compatibility with both the canonical libunwind and the libgcc implementation.

Reviewers: jfb

Subscribers: christof, libcxx-commits

Tags: #libc

Differential Revision: https://reviews.llvm.org/D69677
2019-11-07 14:48:35 -08:00