Hubert Tong
2a0942d3e9
Further to https://github.com/llvm/llvm-project/pull/209306, test a case where a signal handler is a Virtual API function triggered synchronously while the VAPI is not active. Resuming an ancestor context of the signal frame should call the VAPI return glue. --------- Assisted-by: IBM Bob (cherry picked from commit dbaabbc920fcd60aeed5109c3c6353830e7605c5)
116 lines
3.9 KiB
C++
116 lines
3.9 KiB
C++
//===----------------------------------------------------------------------===//
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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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/// Tests unwinding where the signal handler is a VAPI function.
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//
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/// `exit` is used as the signal handler and the unwinding is done in an atexit
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/// handler.
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/// `__builtin_debugtrap` is used because `raise` is also a VAPI function.
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// REQUIRES: target={{.+}}-aix{{.*}}
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// REQUIRES: has-filecheck
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// ADDITIONAL_COMPILE_FLAGS: -fno-inline -fno-exceptions
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// RUN: %{build}
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// RUN: %{exec} %t.exe 2>&1 \
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// RUN: | FileCheck --check-prefix=CHECK \
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// RUN: %if libunwind-assertions-enabled %{ --check-prefix=DEBUG %} \
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// RUN: %s
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#include <errno.h>
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#include <libunwind.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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/// VAPI glue addresses
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constexpr uintptr_t vapi_glue_addr_ext_32 = 0x8b80;
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constexpr uintptr_t vapi_addr_64 = 0x8e00;
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constexpr size_t vapi_size_64 = 0x0200;
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constexpr uintptr_t vapi_glue_addr_begin = vapi_glue_addr_ext_32;
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constexpr uintptr_t vapi_glue_addr_end = vapi_addr_64 + vapi_size_64;
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struct FunctionDescriptor {
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uintptr_t entry;
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uintptr_t toc;
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uintptr_t env;
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};
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void my_atexit_handler(void) {
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FunctionDescriptor *fd = reinterpret_cast<FunctionDescriptor *>(exit);
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bool llu_enabled =
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vapi_glue_addr_begin <= fd->entry && fd->entry < vapi_glue_addr_end;
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fprintf(stderr, "Retrieve a cursor to `main` by stepping up.\n");
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// CHECK-LABEL: Retrieve a cursor to `main`
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unw_context_t context;
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unw_cursor_t cursor;
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unw_getcontext(&context);
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unw_init_local(&cursor, &context);
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/// Step from `my_atexit_handler` up to `exit`.
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unw_step(&cursor);
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if (!llu_enabled)
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fprintf(stderr,
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"libunwind: the next return address=VAPI_NOT_ENABLED from VAPI\n");
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/// Note:
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/// The synthetic VAPI_NOT_ENABLED output would appear _after_ the trace
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/// output indicating that the "next is a signal handler frame". Use DEBUG-DAG
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/// to allow for that.
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// DEBUG-LABEL: libunwind: stepWithTBTable: Look up traceback table of func=_Z17my_atexit_handlerv
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// DEBUG-DAG: libunwind: the next return address={{[^ ]*}} from VAPI
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// DEBUG-DAG: libunwind: The next is a signal handler frame
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/// Step from `exit` (signal handler, VAPI) up to `trapper`.
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unw_step(&cursor);
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if (!llu_enabled)
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fprintf(stderr,
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"libunwind: The return address in stack VAPI_NOT_ENABLED is within "
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"the range of VAPI address; set isKnownVapiNotActive to true\n");
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/// Note:
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/// The synthetic VAPI_NOT_ENABLED output would appear after _all_ of the trace
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/// output from the `unw_step` call. Use DEBUG instead of DEBUG-NEXT to allow
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/// for that.
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// DEBUG-LABEL: libunwind: stepWithTBTable: Look up traceback table of func=exit
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// DEBUG-NEXT: libunwind: Possible signal handler frame
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// DEBUG: libunwind: {{.*}} is within the range of VAPI address; set isKnownVapiNotActive
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/// Step from `trapper` up to `main`.
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unw_step(&cursor);
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// DEBUG-LABEL: libunwind: stepWithTBTable: Look up traceback table of func=_Z7trapperv
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// DEBUG-NOT: VAPI
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fprintf(stderr, "Resume `main` at the call to `trapper`.\n");
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// CHECK-LABEL: Resume `main`
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if (!llu_enabled)
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fprintf(stderr,
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"libunwind: VAPI: executing return glue VAPI_NOT_ENABLED\n");
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unw_resume(&cursor);
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// DEBUG: libunwind: VAPI: executing return glue
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}
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void trapper(void) {
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__builtin_debugtrap();
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_Exit(EXIT_FAILURE);
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}
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int main(void) {
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if (setenv("LIBUNWIND_PRINT_UNWINDING", "1", true) != 0) {
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perror("setenv");
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abort();
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}
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if (atexit(my_atexit_handler) != 0) {
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perror("atexit");
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abort();
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}
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if (signal(SIGTRAP, exit) == SIG_ERR) {
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perror("signal");
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abort();
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}
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trapper();
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_Exit(0);
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}
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