llvm-project/libunwind/test/signal_unwind.pass.cpp
Alastair Houghton fe1301b5d8
[libunwind] Tweak tests for musl support. (#85097)
We can't use `dladdr()` in the tests, because when we're statically
linking with musl that function is a no-op.

Additionally, because musl disables emission of unwind information in
its build, and because its signal trampolines don't include unwind
information, tests that involve unwinding through a signal handler won't
work and need to be disabled for musl.

rdar://123436891
2024-06-10 10:21:13 -04:00

65 lines
1.8 KiB
C++

// -*- 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 the unwinder can cope with the signal handler.
// REQUIRES: target={{(aarch64|riscv64|s390x|x86_64)-.+linux.*}}
// TODO: Figure out why this fails with Memory Sanitizer.
// XFAIL: msan
// Note: this test fails on musl because:
//
// (a) musl disables emission of unwind information for its build, and
// (b) musl's signal trampolines don't include unwind information
//
// XFAIL: target={{.*}}-musl
#undef NDEBUG
#include <assert.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#include <unwind.h>
// Using __attribute__((section("main_func"))) is ELF specific, but then
// this entire test is marked as requiring Linux, so we should be good.
//
// We don't use dladdr() because on musl it's a no-op when statically linked.
extern char __start_main_func;
extern char __stop_main_func;
_Unwind_Reason_Code frame_handler(struct _Unwind_Context* ctx, void* arg) {
(void)arg;
// Unwind until the main is reached, above frames depend on the platform and
// architecture.
uintptr_t ip = _Unwind_GetIP(ctx);
if (ip >= (uintptr_t)&__start_main_func &&
ip < (uintptr_t)&__stop_main_func) {
_Exit(0);
}
return _URC_NO_REASON;
}
void signal_handler(int signum) {
(void)signum;
_Unwind_Backtrace(frame_handler, NULL);
_Exit(-1);
}
__attribute__((section("main_func"))) int main(int, char **) {
signal(SIGUSR1, signal_handler);
kill(getpid(), SIGUSR1);
return -2;
}