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f56ea14c29
Similar to D90898 (Linux AArch64) and D124765 (SystemZ).
On an Arch Linux RISC-V (riscv64gc), the following code
```
#define _GNU_SOURCE
#include <dlfcn.h>
#include <libunwind.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
static void handler(int signo) {
unw_context_t context;
unw_cursor_t cursor;
unw_getcontext(&context);
unw_init_local(&cursor, &context);
unw_word_t pc, sp;
do {
unw_get_reg(&cursor, UNW_REG_IP, &pc);
unw_get_reg(&cursor, UNW_REG_SP, &sp);
printf("pc=0x%016zx sp=0x%016zx", (size_t)pc, (size_t)sp);
Dl_info info = {};
if (dladdr((void *)pc, &info))
printf(" %s:%s", info.dli_fname, info.dli_sname ? info.dli_sname : "");
puts("");
} while (unw_step(&cursor) > 0);
exit(0);
}
int main() {
signal(SIGUSR1, handler);
raise(SIGUSR1);
return 1;
}
```
linked with `-Wl,--export-dynamic` gives an output like
```
pc=0x0000000000010a82 sp=0x00007fffd8a0b910 ./b:
pc=0x00007fffa7e77800 sp=0x00007fffd8a0c520 linux-vdso.so.1:__vdso_rt_sigreturn
pc=0x00007fffa7d73bee sp=0x00007fffd8a0c960 /usr/lib/libc.so.6:
pc=0x00007fffa7d3ed66 sp=0x00007fffd8a0c9b0 /usr/lib/libc.so.6:gsignal
pc=0x0000000000010a3c sp=0x00007fffd8a0c9c0 ./b:main
pc=0x00007fffa7d2f1d4 sp=0x00007fffd8a0c9e0 /usr/lib/libc.so.6:
pc=0x00007fffa7d2f27c sp=0x00007fffd8a0cb10 /usr/lib/libc.so.6:__libc_start_main
pc=0x00000000000109a0 sp=0x00007fffd8a0cb60 ./b:_start
```
Co-Authored-By: Fangrui Song <i@maskray.me>
Reviewed By: #libunwind, MaskRay
Differential Revision: https://reviews.llvm.org/D148499
61 lines
1.7 KiB
C++
61 lines
1.7 KiB
C++
// -*- 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 leaf function can be unwund.
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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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#undef NDEBUG
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#include <assert.h>
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#include <dlfcn.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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_Unwind_Reason_Code frame_handler(struct _Unwind_Context* ctx, void* arg) {
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(void)arg;
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Dl_info info = { 0, 0, 0, 0 };
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// Unwind until the main is reached, above frames deeped on the platform and
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// architecture.
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if (dladdr(reinterpret_cast<void *>(_Unwind_GetIP(ctx)), &info) &&
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info.dli_sname && !strcmp("main", info.dli_sname)) {
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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__((noinline)) void crashing_leaf_func(void) {
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// libunwind searches for the address before the return address which points
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// to the trap instruction. NOP guarantees the trap instruction is not the
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// first instruction of the function.
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// We should keep this here for other unwinders that also decrement pc.
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__asm__ __volatile__("nop");
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__builtin_trap();
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}
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int main(int, char**) {
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signal(SIGTRAP, signal_handler);
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signal(SIGILL, signal_handler);
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crashing_leaf_func();
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return -2;
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}
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