[libunwind][test] Add test to check for unw_resume()

[Ami-zhang]

Summary

This is here for local unwinding, which unw_resume() restores
the machine state and then directly resumes execution in the
target stack frame.

[Ami-zhang]

(1) Test pass on X86

$ ninja check-unwind
Testing Time: 0.29s
  Unsupported:  2
  Passed     : 12

(2) Test results on LoongArch

$ ninja check-unwind
Testing Time: 0.57s
  Unsupported      : 6
  Passed           : 7
  Expectedly Failed: 1

[SixWeining]

There are many CI failures including AIX, FreeBSD and MSAN.

Seems we should add REQUIRES and XFAIL like other tests:

$ grep -rn REQUIRE libunwind/test/
libunwind/test/unwind_leaffunction.pass.cpp:11:// REQUIRES: linux && (target={{aarch64-.+}} || target={{s390x-.+}} || target={{x86_64-.+}})
libunwind/test/floatregister.pass.cpp:10:// REQUIRES: linux && target={{aarch64-.+}}
libunwind/test/remember_state_leak.pass.sh.s:9:# REQUIRES: target={{x86_64-.+-linux-gnu}}
libunwind/test/bad_unwind_info.pass.cpp:13:// REQUIRES: linux && (target={{aarch64-.+}} || target={{s390x-.+}} || target={{x86_64-.+}})
libunwind/test/forceunwind.pass.cpp:10:// REQUIRES: linux
libunwind/test/signal_unwind.pass.cpp:11:// REQUIRES: linux && (target={{aarch64-.+}} || target={{s390x-.+}} || target={{x86_64-.+}})
libunwind/test/unwind_scalable_vectors.pass.cpp:10:// REQUIRES: linux && target={{riscv64-.+}}

$ grep -rn msan libunwind/test/
libunwind/test/unwind_leaffunction.pass.cpp:14:// XFAIL: msan
libunwind/test/signal_frame.pass.cpp:16:// XFAIL: msan
libunwind/test/libunwind_01.pass.cpp:14:// XFAIL: msan
libunwind/test/libunwind_02.pass.cpp:11:// XFAIL: msan
libunwind/test/remember_state_leak.pass.sh.s:12:# UNSUPPORTED: msan
libunwind/test/bad_unwind_info.pass.cpp:19:// UNSUPPORTED: msan
libunwind/test/forceunwind.pass.cpp:13:// XFAIL: msan
libunwind/test/signal_unwind.pass.cpp:14:// XFAIL: msan

[Ami-zhang]

Fix some test issues

[Ami-zhang]

Off clang-format

[arichardson]

libunwind/test/unw_resume.pass.cpp

13

This is overly restrictive, the test looks like it should work anywhere so there should instead be xfails for the cases that are failing.

I know this is what other tests are doing but those should also be changed IMO.

[Ami-zhang]

Address @arichardson's comment

[Ami-zhang]

libunwind/test/unw_resume.pass.cpp

13

Updated it.
Thanks for your suggestion.

[Ami-zhang]

Remove freebsd from XFAIL

[wangleiat]

LGTM

libunwind/test/unw_resume.pass.cpp

+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// Ensure that unw_resume() resumes execution at the stack frame identified by
+// cursor.
+// clang-format off
+// REQUIRES: linux && (target={{aarch64-.+}} || target={{loongarch64-.+}} || target={{s390x-.+}} || target={{x86_64-.+}})
+
+// TODO: Figure out why this fails with Memory Sanitizer.
+// XFAIL: msan
+
+// FIXME: The return address register($ra/$r1) is restored with a destroyed base
+// address register($a0/$r4) in the assembly file `UnwindRegistersRestore.S` on
+// LoongArch. And we will fix this issue in the next commit.
+// XFAIL: target={{loongarch64-.+}}
+
+#include <libunwind.h>
+
+void test_unw_resume() {
+  unw_context_t context;
+  unw_cursor_t cursor;
+
+  unw_getcontext(&context);
+  unw_init_local(&cursor, &context);
+  unw_step(&cursor);
+  unw_resume(&cursor);
+}
+
+int main() {
+  test_unw_resume();
+  return 0;
+}