| //===----------------------------------------------------------------------===// |
| // |
| // 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 |
| // |
| // |
| // Implements gcc extensions to the C++ ABI Exception Handling Level 1. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include <inttypes.h> |
| #include <stdbool.h> |
| #include <stdint.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| |
| #include "config.h" |
| #include "libunwind_ext.h" |
| #include "libunwind.h" |
| #include "Unwind-EHABI.h" |
| #include "unwind.h" |
| |
| #if defined(_LIBUNWIND_BUILD_ZERO_COST_APIS) |
| |
| #if defined(_LIBUNWIND_SUPPORT_SEH_UNWIND) |
| #define PRIVATE_1 private_[0] |
| #elif defined(_LIBUNWIND_ARM_EHABI) |
| #define PRIVATE_1 unwinder_cache.reserved1 |
| #else |
| #define PRIVATE_1 private_1 |
| #endif |
| |
| /// Called by __cxa_rethrow(). |
| _LIBUNWIND_EXPORT _Unwind_Reason_Code |
| _Unwind_Resume_or_Rethrow(_Unwind_Exception *exception_object) { |
| _LIBUNWIND_TRACE_API( |
| "_Unwind_Resume_or_Rethrow(ex_obj=%p), private_1=%" PRIdPTR, |
| (void *)exception_object, (intptr_t)exception_object->PRIVATE_1); |
| |
| // If this is non-forced and a stopping place was found, then this is a |
| // re-throw. |
| // Call _Unwind_RaiseException() as if this was a new exception |
| if (exception_object->PRIVATE_1 == 0) { |
| return _Unwind_RaiseException(exception_object); |
| // Will return if there is no catch clause, so that __cxa_rethrow can call |
| // std::terminate(). |
| } |
| |
| // Call through to _Unwind_Resume() which distiguishes between forced and |
| // regular exceptions. |
| _Unwind_Resume(exception_object); |
| _LIBUNWIND_ABORT("_Unwind_Resume_or_Rethrow() called _Unwind_RaiseException()" |
| " which unexpectedly returned"); |
| } |
| |
| /// Called by personality handler during phase 2 to get base address for data |
| /// relative encodings. |
| _LIBUNWIND_EXPORT uintptr_t |
| _Unwind_GetDataRelBase(struct _Unwind_Context *context) { |
| (void)context; |
| _LIBUNWIND_TRACE_API("_Unwind_GetDataRelBase(context=%p)", (void *)context); |
| _LIBUNWIND_ABORT("_Unwind_GetDataRelBase() not implemented"); |
| } |
| |
| |
| /// Called by personality handler during phase 2 to get base address for text |
| /// relative encodings. |
| _LIBUNWIND_EXPORT uintptr_t |
| _Unwind_GetTextRelBase(struct _Unwind_Context *context) { |
| (void)context; |
| _LIBUNWIND_TRACE_API("_Unwind_GetTextRelBase(context=%p)", (void *)context); |
| _LIBUNWIND_ABORT("_Unwind_GetTextRelBase() not implemented"); |
| } |
| |
| |
| /// Scans unwind information to find the function that contains the |
| /// specified code address "pc". |
| _LIBUNWIND_EXPORT void *_Unwind_FindEnclosingFunction(void *pc) { |
| _LIBUNWIND_TRACE_API("_Unwind_FindEnclosingFunction(pc=%p)", pc); |
| // This is slow, but works. |
| // We create an unwind cursor then alter the IP to be pc |
| unw_cursor_t cursor; |
| unw_context_t uc; |
| unw_proc_info_t info; |
| __unw_getcontext(&uc); |
| __unw_init_local(&cursor, &uc); |
| __unw_set_reg(&cursor, UNW_REG_IP, (unw_word_t)(intptr_t)pc); |
| if (__unw_get_proc_info(&cursor, &info) == UNW_ESUCCESS) |
| return (void *)(intptr_t) info.start_ip; |
| else |
| return NULL; |
| } |
| |
| /// Walk every frame and call trace function at each one. If trace function |
| /// returns anything other than _URC_NO_REASON, then walk is terminated. |
| _LIBUNWIND_EXPORT _Unwind_Reason_Code |
| _Unwind_Backtrace(_Unwind_Trace_Fn callback, void *ref) { |
| unw_cursor_t cursor; |
| unw_context_t uc; |
| __unw_getcontext(&uc); |
| __unw_init_local(&cursor, &uc); |
| |
| _LIBUNWIND_TRACE_API("_Unwind_Backtrace(callback=%p)", |
| (void *)(uintptr_t)callback); |
| |
| #if defined(_LIBUNWIND_ARM_EHABI) |
| // Create a mock exception object for force unwinding. |
| _Unwind_Exception ex; |
| memset(&ex, '\0', sizeof(ex)); |
| strcpy((char *)&ex.exception_class, "CLNGUNW"); |
| #endif |
| |
| // walk each frame |
| while (true) { |
| _Unwind_Reason_Code result; |
| |
| #if !defined(_LIBUNWIND_ARM_EHABI) |
| // ask libunwind to get next frame (skip over first frame which is |
| // _Unwind_Backtrace()) |
| if (__unw_step(&cursor) <= 0) { |
| _LIBUNWIND_TRACE_UNWINDING(" _backtrace: ended because cursor reached " |
| "bottom of stack, returning %d", |
| _URC_END_OF_STACK); |
| return _URC_END_OF_STACK; |
| } |
| #else |
| // Get the information for this frame. |
| unw_proc_info_t frameInfo; |
| if (__unw_get_proc_info(&cursor, &frameInfo) != UNW_ESUCCESS) { |
| return _URC_END_OF_STACK; |
| } |
| |
| // Update the pr_cache in the mock exception object. |
| const uint32_t* unwindInfo = (uint32_t *) frameInfo.unwind_info; |
| ex.pr_cache.fnstart = frameInfo.start_ip; |
| ex.pr_cache.ehtp = (_Unwind_EHT_Header *) unwindInfo; |
| ex.pr_cache.additional= frameInfo.flags; |
| |
| struct _Unwind_Context *context = (struct _Unwind_Context *)&cursor; |
| // Get and call the personality function to unwind the frame. |
| _Unwind_Personality_Fn handler = (_Unwind_Personality_Fn)frameInfo.handler; |
| if (handler == NULL) { |
| return _URC_END_OF_STACK; |
| } |
| if (handler(_US_VIRTUAL_UNWIND_FRAME | _US_FORCE_UNWIND, &ex, context) != |
| _URC_CONTINUE_UNWIND) { |
| return _URC_END_OF_STACK; |
| } |
| #endif // defined(_LIBUNWIND_ARM_EHABI) |
| |
| // debugging |
| if (_LIBUNWIND_TRACING_UNWINDING) { |
| char functionName[512]; |
| unw_proc_info_t frame; |
| unw_word_t offset; |
| __unw_get_proc_name(&cursor, functionName, 512, &offset); |
| __unw_get_proc_info(&cursor, &frame); |
| _LIBUNWIND_TRACE_UNWINDING( |
| " _backtrace: start_ip=0x%" PRIxPTR ", func=%s, lsda=0x%" PRIxPTR ", context=%p", |
| frame.start_ip, functionName, frame.lsda, |
| (void *)&cursor); |
| } |
| |
| // call trace function with this frame |
| result = (*callback)((struct _Unwind_Context *)(&cursor), ref); |
| if (result != _URC_NO_REASON) { |
| _LIBUNWIND_TRACE_UNWINDING( |
| " _backtrace: ended because callback returned %d", result); |
| return result; |
| } |
| } |
| } |
| |
| |
| /// Find DWARF unwind info for an address 'pc' in some function. |
| _LIBUNWIND_EXPORT const void *_Unwind_Find_FDE(const void *pc, |
| struct dwarf_eh_bases *bases) { |
| // This is slow, but works. |
| // We create an unwind cursor then alter the IP to be pc |
| unw_cursor_t cursor; |
| unw_context_t uc; |
| unw_proc_info_t info; |
| __unw_getcontext(&uc); |
| __unw_init_local(&cursor, &uc); |
| __unw_set_reg(&cursor, UNW_REG_IP, (unw_word_t)(intptr_t)pc); |
| __unw_get_proc_info(&cursor, &info); |
| bases->tbase = (uintptr_t)info.extra; |
| bases->dbase = 0; // dbase not used on Mac OS X |
| bases->func = (uintptr_t)info.start_ip; |
| _LIBUNWIND_TRACE_API("_Unwind_Find_FDE(pc=%p) => %p", pc, |
| (void *)(intptr_t) info.unwind_info); |
| return (void *)(intptr_t) info.unwind_info; |
| } |
| |
| /// Returns the CFA (call frame area, or stack pointer at start of function) |
| /// for the current context. |
| _LIBUNWIND_EXPORT uintptr_t _Unwind_GetCFA(struct _Unwind_Context *context) { |
| unw_cursor_t *cursor = (unw_cursor_t *)context; |
| unw_word_t result; |
| __unw_get_reg(cursor, UNW_REG_SP, &result); |
| _LIBUNWIND_TRACE_API("_Unwind_GetCFA(context=%p) => 0x%" PRIxPTR, |
| (void *)context, result); |
| return (uintptr_t)result; |
| } |
| |
| |
| /// Called by personality handler during phase 2 to get instruction pointer. |
| /// ipBefore is a boolean that says if IP is already adjusted to be the call |
| /// site address. Normally IP is the return address. |
| _LIBUNWIND_EXPORT uintptr_t _Unwind_GetIPInfo(struct _Unwind_Context *context, |
| int *ipBefore) { |
| _LIBUNWIND_TRACE_API("_Unwind_GetIPInfo(context=%p)", (void *)context); |
| int isSignalFrame = __unw_is_signal_frame((unw_cursor_t *)context); |
| // Negative means some kind of error (probably UNW_ENOINFO), but we have no |
| // good way to report that, and this maintains backward compatibility with the |
| // implementation that hard-coded zero in every case, even signal frames. |
| if (isSignalFrame <= 0) |
| *ipBefore = 0; |
| else |
| *ipBefore = 1; |
| return _Unwind_GetIP(context); |
| } |
| |
| #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND) |
| |
| /// Called by programs with dynamic code generators that want |
| /// to register a dynamically generated FDE. |
| /// This function has existed on Mac OS X since 10.4, but |
| /// was broken until 10.6. |
| _LIBUNWIND_EXPORT void __register_frame(const void *fde) { |
| _LIBUNWIND_TRACE_API("__register_frame(%p)", fde); |
| __unw_add_dynamic_fde((unw_word_t)(uintptr_t)fde); |
| } |
| |
| |
| /// Called by programs with dynamic code generators that want |
| /// to unregister a dynamically generated FDE. |
| /// This function has existed on Mac OS X since 10.4, but |
| /// was broken until 10.6. |
| _LIBUNWIND_EXPORT void __deregister_frame(const void *fde) { |
| _LIBUNWIND_TRACE_API("__deregister_frame(%p)", fde); |
| __unw_remove_dynamic_fde((unw_word_t)(uintptr_t)fde); |
| } |
| |
| |
| // The following register/deregister functions are gcc extensions. |
| // They have existed on Mac OS X, but have never worked because Mac OS X |
| // before 10.6 used keymgr to track known FDEs, but these functions |
| // never got updated to use keymgr. |
| // For now, we implement these as do-nothing functions to keep any existing |
| // applications working. We also add the not in 10.6 symbol so that nwe |
| // application won't be able to use them. |
| |
| #if defined(_LIBUNWIND_SUPPORT_FRAME_APIS) |
| _LIBUNWIND_EXPORT void __register_frame_info_bases(const void *fde, void *ob, |
| void *tb, void *db) { |
| (void)fde; |
| (void)ob; |
| (void)tb; |
| (void)db; |
| _LIBUNWIND_TRACE_API("__register_frame_info_bases(%p,%p, %p, %p)", |
| fde, ob, tb, db); |
| // do nothing, this function never worked in Mac OS X |
| } |
| |
| _LIBUNWIND_EXPORT void __register_frame_info(const void *fde, void *ob) { |
| (void)fde; |
| (void)ob; |
| _LIBUNWIND_TRACE_API("__register_frame_info(%p, %p)", fde, ob); |
| // do nothing, this function never worked in Mac OS X |
| } |
| |
| _LIBUNWIND_EXPORT void __register_frame_info_table_bases(const void *fde, |
| void *ob, void *tb, |
| void *db) { |
| (void)fde; |
| (void)ob; |
| (void)tb; |
| (void)db; |
| _LIBUNWIND_TRACE_API("__register_frame_info_table_bases" |
| "(%p,%p, %p, %p)", fde, ob, tb, db); |
| // do nothing, this function never worked in Mac OS X |
| } |
| |
| _LIBUNWIND_EXPORT void __register_frame_info_table(const void *fde, void *ob) { |
| (void)fde; |
| (void)ob; |
| _LIBUNWIND_TRACE_API("__register_frame_info_table(%p, %p)", fde, ob); |
| // do nothing, this function never worked in Mac OS X |
| } |
| |
| _LIBUNWIND_EXPORT void __register_frame_table(const void *fde) { |
| (void)fde; |
| _LIBUNWIND_TRACE_API("__register_frame_table(%p)", fde); |
| // do nothing, this function never worked in Mac OS X |
| } |
| |
| _LIBUNWIND_EXPORT void *__deregister_frame_info(const void *fde) { |
| (void)fde; |
| _LIBUNWIND_TRACE_API("__deregister_frame_info(%p)", fde); |
| // do nothing, this function never worked in Mac OS X |
| return NULL; |
| } |
| |
| _LIBUNWIND_EXPORT void *__deregister_frame_info_bases(const void *fde) { |
| (void)fde; |
| _LIBUNWIND_TRACE_API("__deregister_frame_info_bases(%p)", fde); |
| // do nothing, this function never worked in Mac OS X |
| return NULL; |
| } |
| #endif // defined(_LIBUNWIND_SUPPORT_FRAME_APIS) |
| |
| #endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND) |
| |
| #endif // defined(_LIBUNWIND_BUILD_ZERO_COST_APIS) |