| //===----------------------------------------------------------------------===// |
| // |
| // 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 |
| // |
| //===----------------------------------------------------------------------===// |
| |
| // Test that _Unwind_Backtrace() walks up from a signal handler and produces |
| // a correct traceback when the function raising the signal does not save |
| // the link register or does not store the stack back chain. |
| |
| // REQUIRES: target={{.+}}-aix{{.*}} |
| |
| // Test when the function raising the signal does not save the link register |
| // RUN: %{cxx} -x c++ %s -o %t.exe -DCXX_CODE %{flags} %{compile_flags} |
| // RUN: %{exec} %t.exe |
| |
| // Test when the function raising the signal does not store stack back chain. |
| // RUN: %{cxx} -x c++ -c %s -o %t1.o -DCXX_CODE -DNOBACKCHAIN %{flags} \ |
| // RUN: %{compile_flags} |
| // RUN: %{cxx} -c %s -o %t2.o %{flags} %{compile_flags} |
| // RUN: %{cxx} -o %t1.exe %t1.o %t2.o %{flags} %{link_flags} |
| // RUN: %{exec} %t1.exe |
| |
| #ifdef CXX_CODE |
| |
| #undef NDEBUG |
| #include <assert.h> |
| #include <signal.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/debug.h> |
| #include <unwind.h> |
| |
| #define NAME_ARRAY_SIZE 10 |
| #define NAMES_EXPECTED 6 |
| |
| const char* namesExpected[] = {"handler", "abc", "bar", "foo", "main", |
| "__start"}; |
| char *namesObtained[NAME_ARRAY_SIZE] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0}; |
| |
| int funcIndex = 0; |
| |
| // Get the function name from traceback table. |
| char *getFuncName(uintptr_t pc, uint16_t *nameLen) { |
| uint32_t *p = reinterpret_cast<uint32_t *>(pc); |
| |
| // Keep looking forward until a word of 0 is found. The traceback |
| // table starts at the following word. |
| while (*p) |
| ++p; |
| tbtable *TBTable = reinterpret_cast<tbtable *>(p + 1); |
| |
| if (!TBTable->tb.name_present) |
| return NULL; |
| |
| // Get to the optional portion of the traceback table. |
| p = reinterpret_cast<uint32_t *>(&TBTable->tb_ext); |
| |
| // Skip field parminfo if it exists. |
| if (TBTable->tb.fixedparms || TBTable->tb.floatparms) |
| ++p; |
| |
| // Skip field tb_offset if it exists. |
| if (TBTable->tb.has_tboff) |
| ++p; |
| |
| // Skip field hand_mask if it exists. |
| if (TBTable->tb.int_hndl) |
| ++p; |
| |
| // Skip fields ctl_info and ctl_info_disp if they exist. |
| if (TBTable->tb.has_ctl) |
| p += 1 + *p; |
| |
| *nameLen = *reinterpret_cast<uint16_t *>(p); |
| return reinterpret_cast<char *>(p) + sizeof(uint16_t); |
| } |
| |
| _Unwind_Reason_Code callBack(struct _Unwind_Context *uc, void *arg) { |
| (void)arg; |
| uint16_t nameLen; |
| uintptr_t ip = _Unwind_GetIP(uc); |
| if (funcIndex < NAME_ARRAY_SIZE) |
| namesObtained[funcIndex++] = strndup(getFuncName(ip, &nameLen), nameLen); |
| return _URC_NO_REASON; |
| } |
| |
| extern "C" void handler(int signum) { |
| (void)signum; |
| // Walk stack frames for traceback. |
| _Unwind_Backtrace(callBack, NULL); |
| |
| // Verify the traceback. |
| assert(funcIndex <= NAMES_EXPECTED && "Obtained names more than expected"); |
| for (int i = 0; i < funcIndex; ++i) { |
| assert(!strcmp(namesExpected[i], namesObtained[i]) && |
| "Function names do not match"); |
| free(namesObtained[i]); |
| } |
| exit(0); |
| } |
| |
| #ifdef NOBACKCHAIN |
| // abc() is in assembly. It raises signal SIGSEGV and does not store |
| // the stack back chain. |
| extern "C" void abc(); |
| |
| #else |
| volatile int *null = 0; |
| |
| // abc() raises signal SIGSEGV and does not save the link register. |
| extern "C" __attribute__((noinline)) void abc() { |
| // Produce a SIGSEGV. |
| *null = 0; |
| } |
| #endif |
| |
| extern "C" __attribute__((noinline)) void bar() { |
| abc(); |
| } |
| |
| extern "C" __attribute__((noinline)) void foo() { |
| bar(); |
| } |
| |
| int main() { |
| // Set signal handler for SIGSEGV. |
| signal(SIGSEGV, handler); |
| foo(); |
| } |
| |
| #else // Assembly code for abc(). |
| // This assembly code is similar to the following C code but it saves the |
| // link register. |
| // |
| // int *badp = 0; |
| // void abc() { |
| // *badp = 0; |
| // } |
| |
| #ifdef __64BIT__ |
| .csect [PR],5 |
| .file "abc.c" |
| .globl abc[DS] # -- Begin function abc |
| .globl .abc |
| .align 4 |
| .csect abc[DS],3 |
| .vbyte 8, .abc # @abc |
| .vbyte 8, TOC[TC0] |
| .vbyte 8, 0 |
| .csect [PR],5 |
| .abc: |
| # %bb.0: # %entry |
| mflr 0 |
| std 0, 16(1) |
| ld 3, L..C0(2) # @badp |
| bl $+4 |
| ld 4, 0(3) |
| li 3, 0 |
| stw 3, 0(4) |
| ld 0, 16(1) |
| mtlr 0 |
| blr |
| L..abc0: |
| .vbyte 4, 0x00000000 # Traceback table begin |
| .byte 0x00 # Version = 0 |
| .byte 0x09 # Language = CPlusPlus |
| .byte 0x20 # -IsGlobaLinkage, -IsOutOfLineEpilogOrPrologue |
| # +HasTraceBackTableOffset, -IsInternalProcedure |
| # -HasControlledStorage, -IsTOCless |
| # -IsFloatingPointPresent |
| # -IsFloatingPointOperationLogOrAbortEnabled |
| .byte 0x61 # -IsInterruptHandler, +IsFunctionNamePresent, +IsAllocaUsed |
| # OnConditionDirective = 0, -IsCRSaved, +IsLRSaved |
| .byte 0x00 # -IsBackChainStored, -IsFixup, NumOfFPRsSaved = 0 |
| .byte 0x01 # -HasExtensionTable, -HasVectorInfo, NumOfGPRsSaved = 1 |
| .byte 0x00 # NumberOfFixedParms = 0 |
| .byte 0x01 # NumberOfFPParms = 0, +HasParmsOnStack |
| .vbyte 4, L..abc0-.abc # Function size |
| .vbyte 2, 0x0003 # Function name len = 3 |
| .byte "abc" # Function Name |
| .byte 0x1f # AllocaUsed |
| # -- End function |
| .csect badp[RW],3 |
| .globl badp[RW] # @badp |
| .align 3 |
| .vbyte 8, 0 |
| .toc |
| L..C0: |
| .tc badp[TC],badp[RW] |
| #else |
| .csect [PR],5 |
| .file "abc.c" |
| .globl abc[DS] # -- Begin function abc |
| .globl .abc |
| .align 4 |
| .csect abc[DS],2 |
| .vbyte 4, .abc # @abc |
| .vbyte 4, TOC[TC0] |
| .vbyte 4, 0 |
| .csect [PR],5 |
| .abc: |
| # %bb.0: # %entry |
| mflr 0 |
| stw 0, 8(1) |
| lwz 3, L..C0(2) # @badp |
| bl $+4 |
| lwz 4, 0(3) |
| li 3, 0 |
| stw 3, 0(4) |
| lwz 0, 8(1) |
| mtlr 0 |
| blr |
| L..abc0: |
| .vbyte 4, 0x00000000 # Traceback table begin |
| .byte 0x00 # Version = 0 |
| .byte 0x09 # Language = CPlusPlus |
| .byte 0x20 # -IsGlobaLinkage, -IsOutOfLineEpilogOrPrologue |
| # +HasTraceBackTableOffset, -IsInternalProcedure |
| # -HasControlledStorage, -IsTOCless |
| # -IsFloatingPointPresent |
| # -IsFloatingPointOperationLogOrAbortEnabled |
| .byte 0x61 # -IsInterruptHandler, +IsFunctionNamePresent, +IsAllocaUsed |
| # OnConditionDirective = 0, -IsCRSaved, +IsLRSaved |
| .byte 0x00 # -IsBackChainStored, -IsFixup, NumOfFPRsSaved = 0 |
| .byte 0x01 # -HasExtensionTable, -HasVectorInfo, NumOfGPRsSaved = 1 |
| .byte 0x00 # NumberOfFixedParms = 0 |
| .byte 0x01 # NumberOfFPParms = 0, +HasParmsOnStack |
| .vbyte 4, L..abc0-.abc # Function size |
| .vbyte 2, 0x0003 # Function name len = 3 |
| .byte "abc" # Function Name |
| .byte 0x1f # AllocaUsed |
| # -- End function |
| .csect badp[RW],2 |
| .globl badp[RW] # @badp |
| .align 2 |
| .vbyte 4, 0 |
| .toc |
| L..C0: |
| .tc badp[TC],badp[RW] |
| #endif // __64BIT__ |
| #endif // CXX_CODE |
