[libunwind] Use the from-scratch testing configuration by default

[ldionne]

Summary

This commit switches libunwind from using the complicated logic in
libc++'s testing configuration to a from-scratch configuration.
I tried to make sure that all cases that were handled in the old
config were handled by this one too, so hopefully this shouldn't
break anyone. However, if you encounter issues with this change,
please let me know and feel free to revert if I don't reply quickly.

This change was engineered to be easily revertable.

[ldionne]

Rebase onto main

[ldionne]

Shipping this, as I mentioned please feel free to revert if this causes issues. If you do, please explain those issues so we can fix them before we try again.

[phosek]

I think this may have broken our builders since all libunwind tests now fail with the same error:

Script:
--
: 'COMPILED WITH';  /b/s/w/ir/x/w/staging/llvm_build/./bin/clang++ /b/s/w/ir/x/w/llvm-project/libunwind/test/forceunwind.pass.cpp  --target=x86_64-unknown-linux-gnu -nostdinc++ -I /b/s/w/ir/x/w/llvm-project/libunwind/include -funwind-tables -std=c++2b -Werror -Wall -Wextra -Wshadow -Wundef -Wno-unused-command-line-argument -Wno-attributes -Wno-pessimizing-move -Wno-c++11-extensions -Wno-user-defined-literals -Wno-noexcept-type -Wno-atomic-alignment -Wsign-compare -Wunused-variable -Wunused-parameter -Wunreachable-code -Wno-unused-local-typedef -D_LIBCPP_DISABLE_AVAILABILITY -fcoroutines-ts -Werror=thread-safety -Wuser-defined-warnings -D_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER  -nodefaultlibs /b/s/w/ir/x/w/staging/llvm_build/runtimes/runtimes-x86_64-unknown-linux-gnu-bins/lib/libunwind.a -ldl -lc -lpthread -Wl,--export-dynamic -o /b/s/w/ir/x/w/staging/llvm_build/runtimes/runtimes-x86_64-unknown-linux-gnu-bins/Output/forceunwind.pass.cpp.dir/t.tmp.exe
: 'EXECUTED AS';  /b/s/w/ir/cipd_bin_packages/cpython3/bin/python3.8 /b/s/w/ir/x/w/llvm-project/libunwind/../libcxx/utils/run.py --execdir /b/s/w/ir/x/w/staging/llvm_build/runtimes/runtimes-x86_64-unknown-linux-gnu-bins/Output/forceunwind.pass.cpp.dir --  /b/s/w/ir/x/w/staging/llvm_build/runtimes/runtimes-x86_64-unknown-linux-gnu-bins/Output/forceunwind.pass.cpp.dir/t.tmp.exe
--
Exit Code: 1

Command Output (stdout):
--
$ ":" "COMPILED WITH"
$ "/b/s/w/ir/x/w/staging/llvm_build/./bin/clang++" "/b/s/w/ir/x/w/llvm-project/libunwind/test/forceunwind.pass.cpp" "--target=x86_64-unknown-linux-gnu" "-nostdinc++" "-I" "/b/s/w/ir/x/w/llvm-project/libunwind/include" "-funwind-tables" "-std=c++2b" "-Werror" "-Wall" "-Wextra" "-Wshadow" "-Wundef" "-Wno-unused-command-line-argument" "-Wno-attributes" "-Wno-pessimizing-move" "-Wno-c++11-extensions" "-Wno-user-defined-literals" "-Wno-noexcept-type" "-Wno-atomic-alignment" "-Wsign-compare" "-Wunused-variable" "-Wunused-parameter" "-Wunreachable-code" "-Wno-unused-local-typedef" "-D_LIBCPP_DISABLE_AVAILABILITY" "-fcoroutines-ts" "-Werror=thread-safety" "-Wuser-defined-warnings" "-D_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER" "-nodefaultlibs" "/b/s/w/ir/x/w/staging/llvm_build/runtimes/runtimes-x86_64-unknown-linux-gnu-bins/lib/libunwind.a" "-ldl" "-lc" "-lpthread" "-Wl,--export-dynamic" "-o" "/b/s/w/ir/x/w/staging/llvm_build/runtimes/runtimes-x86_64-unknown-linux-gnu-bins/Output/forceunwind.pass.cpp.dir/t.tmp.exe"
# command stderr:
clang-14: error: no such file or directory: '/b/s/w/ir/x/w/staging/llvm_build/runtimes/runtimes-x86_64-unknown-linux-gnu-bins/lib/libunwind.a'

error: command failed with exit status: 1

--

The /b/s/w/ir/x/w/staging/llvm_build/runtimes/runtimes-x86_64-unknown-linux-gnu-bins/lib/libunwind.a is invalid, in the bootstrapping build it should be /b/s/w/ir/x/w/staging/llvm_build/lib/x86_64-unknown-linux-gnu/libunwind.a.

[ldionne]

In D112082#3075635, @phosek wrote:

I think this may have broken our builders since all libunwind tests now fail with the same error:
[...]
The /b/s/w/ir/x/w/staging/llvm_build/runtimes/runtimes-x86_64-unknown-linux-gnu-bins/lib/libunwind.a is invalid, in the bootstrapping build it should be /b/s/w/ir/x/w/staging/llvm_build/lib/x86_64-unknown-linux-gnu/libunwind.a.

This is weird, the bootstrapping build does use the from-scratch config. Are you able to reproduce the issue if you specify -DLIBUNWIND_TEST_CONFIG=llvm-libunwind-shared.cfg.in manually? If so, can you share your build incantation so I can reproduce on my side?

[ldionne]

In D112082#3076522, @ldionne wrote:

In D112082#3075635, @phosek wrote:

I think this may have broken our builders since all libunwind tests now fail with the same error:
[...]
The /b/s/w/ir/x/w/staging/llvm_build/runtimes/runtimes-x86_64-unknown-linux-gnu-bins/lib/libunwind.a is invalid, in the bootstrapping build it should be /b/s/w/ir/x/w/staging/llvm_build/lib/x86_64-unknown-linux-gnu/libunwind.a.

This is weird, the bootstrapping build does use the from-scratch config. Are you able to reproduce the issue if you specify -DLIBUNWIND_TEST_CONFIG=llvm-libunwind-shared.cfg.in manually? If so, can you share your build incantation so I can reproduce on my side?

Ahhhh! I guess it might be because you are using the Bootstrapping build AND the static library, which we are not testing. I'll try to reproduce locally.

[gulfem]

Thanks for the revert @ldionne

Here's are the links to the failing Fuchsia builders that @phosek mentioned above:
https://luci-milo.appspot.com/ui/p/fuchsia/builders/toolchain.ci/clang-linux-x64/b8832846561467531729/overview

Here's the cmake command that we use:
https://logs.chromium.org/logs/fuchsia/buildbucket/cr-buildbucket/8832846561467531729/+/u/clang/configure/execution_details

Here's the tests that we run:
https://logs.chromium.org/logs/fuchsia/buildbucket/cr-buildbucket/8832846561467531729/+/u/clang/test/execution_details

Please let me know if you need further help.

[ldionne]

In D112082#3076567, @gulfem wrote:

Thanks for the revert @ldionne

Here's are the links to the failing Fuchsia builders that @phosek mentioned above:
https://luci-milo.appspot.com/ui/p/fuchsia/builders/toolchain.ci/clang-linux-x64/b8832846561467531729/overview

Here's the cmake command that we use:
https://logs.chromium.org/logs/fuchsia/buildbucket/cr-buildbucket/8832846561467531729/+/u/clang/configure/execution_details

Here's the tests that we run:
https://logs.chromium.org/logs/fuchsia/buildbucket/cr-buildbucket/8832846561467531729/+/u/clang/test/execution_details

Please let me know if you need further help.

Thanks a lot for the info. I'm trying to repro locally. I assume the issue is that the from-scratch config doesn't handle per-target runtime directories properly, but I want to see the details.

[ldionne]

Rebase onto main after (hopefully) fixing the Fuchsia failures. @gulfem or @phosek could one of you please apply this patch locally and confirm it fixed the issues? I did it locally, but I might not have been using exactly the same setup.

[ldionne]

I'm going to land this again and worst case we can revert it swiftly if it breaks bots.

[gulfem]

Hi @ldionne,
I had a bad internet connection yesterday, and I just found a chance to respond to you today.
With your reland, Fuchsia builders seems fine.

[ldionne]

In D112082#3087804, @gulfem wrote:

Hi @ldionne,
I had a bad internet connection yesterday, and I just found a chance to respond to you today.
With your reland, Fuchsia builders seems fine.

Awesome, thanks!

[vvereschaka]

Hi @ldione,

these changes break the remote test execution on the cross toolchain builders. The libunwind tests get running on the local host instead of the remote target.
https://lab.llvm.org/buildbot/#/builders/60/builds/5235

libunwind/CMakeLists.txt

cmake_dependent_option(LIBUNWIND_INSTALL_SHARED_LIBRARY
   "LIBUNWIND_ENABLE_SHARED;LIBUNWIND_INSTALL_LIBRARY" OFF)
 set(LIBUNWIND_TARGET_TRIPLE "${LLVM_DEFAULT_TARGET_TRIPLE}" CACHE STRING "Target triple for cross compiling.")
 set(LIBUNWIND_GCC_TOOLCHAIN "" CACHE PATH "GCC toolchain for cross compiling.")
 set(LIBUNWIND_SYSROOT "" CACHE PATH "Sysroot for cross compiling.")
 set(LIBUNWIND_TEST_LINKER_FLAGS "" CACHE STRING
     "Additional linker flags for test programs.")
 set(LIBUNWIND_TEST_COMPILER_FLAGS "" CACHE STRING
     "Additional compiler flags for test programs.")
-set(LIBUNWIND_TEST_CONFIG "${CMAKE_CURRENT_SOURCE_DIR}/test/lit.site.cfg.in" CACHE STRING
+
+if (LIBUNWIND_ENABLE_SHARED)
+  set(LIBUNWIND_DEFAULT_TEST_CONFIG "llvm-libunwind-shared.cfg.in")
+else()
+  set(LIBUNWIND_DEFAULT_TEST_CONFIG "llvm-libunwind-static.cfg.in")
+endif()
+set(LIBUNWIND_TEST_CONFIG "${LIBUNWIND_DEFAULT_TEST_CONFIG}" CACHE STRING
   "The path to the Lit testing configuration to use when running the tests.
    If a relative path is provided, it is assumed to be relative to '<monorepo>/libunwind/test/configs'.")
 if (NOT IS_ABSOLUTE "${LIBUNWIND_TEST_CONFIG}")
   set(LIBUNWIND_TEST_CONFIG "${CMAKE_CURRENT_SOURCE_DIR}/test/configs/${LIBUNWIND_TEST_CONFIG}")
 endif()
 set(LIBUNWIND_TEST_PARAMS "" CACHE STRING
     "A list of parameters to run the Lit test suite with.")