| 1 | // -*- C++ -*- |
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| 2 | //===----------------------------------------------------------------------===// |
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| 3 | // |
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| 4 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 5 | // See https://llvm.org/LICENSE.txt for license information. |
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| 6 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 7 | // |
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| 8 | //===----------------------------------------------------------------------===// |
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| 9 | |
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| 10 | // Ensure that leaf function can be unwund. |
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| 11 | // REQUIRES: target={{(aarch64|loongarch64|riscv64|s390x|x86_64)-.+linux.*}} |
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| 12 | |
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| 13 | // TODO: Figure out why this fails with Memory Sanitizer. |
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| 14 | // XFAIL: msan |
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| 15 | |
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| 16 | // Note: this test fails on musl because: |
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| 17 | // |
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| 18 | // (a) musl disables emission of unwind information for its build, and |
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| 19 | // (b) musl's signal trampolines don't include unwind information |
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| 20 | // |
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| 21 | // XFAIL: target={{.*}}-musl |
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| 22 | |
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| 23 | #undef NDEBUG |
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| 24 | #include <assert.h> |
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| 25 | #include <signal.h> |
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| 26 | #include <stdio.h> |
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| 27 | #include <stdlib.h> |
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| 28 | #include <string.h> |
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| 29 | #include <sys/types.h> |
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| 30 | #include <unistd.h> |
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| 31 | #include <unwind.h> |
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| 32 | |
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| 33 | // Using __attribute__((section("main_func"))) is ELF specific, but then |
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| 34 | // this entire test is marked as requiring Linux, so we should be good. |
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| 35 | // |
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| 36 | // We don't use dladdr() because on musl it's a no-op when statically linked. |
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| 37 | extern char __start_main_func; |
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| 38 | extern char __stop_main_func; |
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| 39 | |
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| 40 | _Unwind_Reason_Code frame_handler(struct _Unwind_Context* ctx, void* arg) { |
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| 41 | (void)arg; |
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| 42 | |
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| 43 | // Unwind until the main is reached, above frames depend on the platform and |
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| 44 | // architecture. |
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| 45 | uintptr_t ip = _Unwind_GetIP(ctx); |
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| 46 | if (ip >= (uintptr_t)&__start_main_func && |
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| 47 | ip < (uintptr_t)&__stop_main_func) { |
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| 48 | _Exit(status: 0); |
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| 49 | } |
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| 50 | |
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| 51 | return _URC_NO_REASON; |
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| 52 | } |
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| 53 | |
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| 54 | void signal_handler(int signum) { |
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| 55 | (void)signum; |
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| 56 | _Unwind_Backtrace(frame_handler, NULL); |
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| 57 | _Exit(status: -1); |
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| 58 | } |
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| 59 | |
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| 60 | __attribute__((noinline)) void crashing_leaf_func(int do_trap) { |
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| 61 | // libunwind searches for the address before the return address which points |
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| 62 | // to the trap instruction. We make the trap conditional and prevent inlining |
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| 63 | // of the function to ensure that the compiler doesn't remove the `ret` |
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| 64 | // instruction altogether. |
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| 65 | // |
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| 66 | // It's also important that the trap instruction isn't the first instruction |
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| 67 | // in the function (which it isn't because of the branch) for other unwinders |
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| 68 | // that also decrement pc. |
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| 69 | if (do_trap) |
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| 70 | __builtin_trap(); |
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| 71 | } |
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| 72 | |
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| 73 | __attribute__((section("main_func" ))) int main(int, char **) { |
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| 74 | signal(SIGTRAP, handler: signal_handler); |
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| 75 | signal(SIGILL, handler: signal_handler); |
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| 76 | crashing_leaf_func(do_trap: 1); |
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| 77 | return -2; |
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| 78 | } |
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| 79 | |
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