llvm-project

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// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// Ensure that the unwinder can cope with the signal handler.
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// REQUIRES: target={{(aarch64|riscv64|s390x|x86_64)-.+linux.*}}
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// TODO: Figure out why this fails with Memory Sanitizer.
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// XFAIL: msan
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// Note: this test fails on musl because:
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//
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//  (a) musl disables emission of unwind information for its build, and
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//  (b) musl's signal trampolines don't include unwind information
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//
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// XFAIL: target={{.*}}-musl
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#undef NDEBUG
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#include <assert.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <unwind.h>
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// Using __attribute__((section("main_func"))) is ELF specific, but then
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// this entire test is marked as requiring Linux, so we should be good.
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//
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// We don't use dladdr() because on musl it's a no-op when statically linked.
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extern char __start_main_func;
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extern char __stop_main_func;
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_Unwind_Reason_Code frame_handler(struct _Unwind_Context* ctx, void* arg) {
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  (void)arg;
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  // Unwind until the main is reached, above frames depend on the platform and
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  // architecture.
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  uintptr_t ip = _Unwind_GetIP(ctx);
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  if (ip >= (uintptr_t)&__start_main_func &&
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      ip < (uintptr_t)&__stop_main_func) {
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    _Exit(0);
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  }
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  return _URC_NO_REASON;
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}
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void signal_handler(int signum) {
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  (void)signum;
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  _Unwind_Backtrace(frame_handler, NULL);
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  _Exit(-1);
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}
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__attribute__((section("main_func"))) int main(int, char **) {
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  signal(SIGUSR1, signal_handler);
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  kill(getpid(), SIGUSR1);
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  return -2;
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}
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