| //===------------------------- cxa_exception.cpp --------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is dual licensed under the MIT and the University of Illinois Open |
| // Source Licenses. See LICENSE.TXT for details. |
| // |
| // |
| // This file implements the "Exception Handling APIs" |
| // http://mentorembedded.github.io/cxx-abi/abi-eh.html |
| // http://www.intel.com/design/itanium/downloads/245358.htm |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include <assert.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <typeinfo> |
| |
| #include "__cxxabi_config.h" |
| #include "cxa_exception.hpp" |
| #include "cxa_handlers.hpp" |
| #include "private_typeinfo.h" |
| #include "unwind.h" |
| |
| #if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__) |
| #include <windows.h> |
| #include <winnt.h> |
| |
| extern "C" EXCEPTION_DISPOSITION _GCC_specific_handler(PEXCEPTION_RECORD, |
| void *, PCONTEXT, |
| PDISPATCHER_CONTEXT, |
| _Unwind_Personality_Fn); |
| #endif |
| |
| /* |
| Exception Header Layout: |
| |
| +---------------------------+-----------------------------+---------------+ |
| | __cxa_exception | _Unwind_Exception CLNGC++\0 | thrown object | |
| +---------------------------+-----------------------------+---------------+ |
| ^ |
| | |
| +-------------------------------------------------------+ |
| | |
| +---------------------------+-----------------------------+ |
| | __cxa_dependent_exception | _Unwind_Exception CLNGC++\1 | |
| +---------------------------+-----------------------------+ |
| |
| Exception Handling Table Layout: |
| |
| +-----------------+--------+ |
| | lpStartEncoding | (char) | |
| +---------+-------+--------+---------------+-----------------------+ |
| | lpStart | (encoded with lpStartEncoding) | defaults to funcStart | |
| +---------+-----+--------+-----------------+---------------+-------+ |
| | ttypeEncoding | (char) | Encoding of the type_info table | |
| +---------------+-+------+----+----------------------------+----------------+ |
| | classInfoOffset | (ULEB128) | Offset to type_info table, defaults to null | |
| +-----------------++--------+-+----------------------------+----------------+ |
| | callSiteEncoding | (char) | Encoding for Call Site Table | |
| +------------------+--+-----+-----+------------------------+--------------------------+ |
| | callSiteTableLength | (ULEB128) | Call Site Table length, used to find Action table | |
| +---------------------+-----------+---------------------------------------------------+ |
| #ifndef __USING_SJLJ_EXCEPTIONS__ |
| +---------------------+-----------+------------------------------------------------+ |
| | Beginning of Call Site Table The current ip lies within the | |
| | ... (start, length) range of one of these | |
| | call sites. There may be action needed. | |
| | +-------------+---------------------------------+------------------------------+ | |
| | | start | (encoded with callSiteEncoding) | offset relative to funcStart | | |
| | | length | (encoded with callSiteEncoding) | length of code fragment | | |
| | | landingPad | (encoded with callSiteEncoding) | offset relative to lpStart | | |
| | | actionEntry | (ULEB128) | Action Table Index 1-based | | |
| | | | | actionEntry == 0 -> cleanup | | |
| | +-------------+---------------------------------+------------------------------+ | |
| | ... | |
| +----------------------------------------------------------------------------------+ |
| #else // __USING_SJLJ_EXCEPTIONS__ |
| +---------------------+-----------+------------------------------------------------+ |
| | Beginning of Call Site Table The current ip is a 1-based index into | |
| | ... this table. Or it is -1 meaning no | |
| | action is needed. Or it is 0 meaning | |
| | terminate. | |
| | +-------------+---------------------------------+------------------------------+ | |
| | | landingPad | (ULEB128) | offset relative to lpStart | | |
| | | actionEntry | (ULEB128) | Action Table Index 1-based | | |
| | | | | actionEntry == 0 -> cleanup | | |
| | +-------------+---------------------------------+------------------------------+ | |
| | ... | |
| +----------------------------------------------------------------------------------+ |
| #endif // __USING_SJLJ_EXCEPTIONS__ |
| +---------------------------------------------------------------------+ |
| | Beginning of Action Table ttypeIndex == 0 : cleanup | |
| | ... ttypeIndex > 0 : catch | |
| | ttypeIndex < 0 : exception spec | |
| | +--------------+-----------+--------------------------------------+ | |
| | | ttypeIndex | (SLEB128) | Index into type_info Table (1-based) | | |
| | | actionOffset | (SLEB128) | Offset into next Action Table entry | | |
| | +--------------+-----------+--------------------------------------+ | |
| | ... | |
| +---------------------------------------------------------------------+-----------------+ |
| | type_info Table, but classInfoOffset does *not* point here! | |
| | +----------------+------------------------------------------------+-----------------+ | |
| | | Nth type_info* | Encoded with ttypeEncoding, 0 means catch(...) | ttypeIndex == N | | |
| | +----------------+------------------------------------------------+-----------------+ | |
| | ... | |
| | +----------------+------------------------------------------------+-----------------+ | |
| | | 1st type_info* | Encoded with ttypeEncoding, 0 means catch(...) | ttypeIndex == 1 | | |
| | +----------------+------------------------------------------------+-----------------+ | |
| | +---------------------------------------+-----------+------------------------------+ | |
| | | 1st ttypeIndex for 1st exception spec | (ULEB128) | classInfoOffset points here! | | |
| | | ... | (ULEB128) | | | |
| | | Mth ttypeIndex for 1st exception spec | (ULEB128) | | | |
| | | 0 | (ULEB128) | | | |
| | +---------------------------------------+------------------------------------------+ | |
| | ... | |
| | +---------------------------------------+------------------------------------------+ | |
| | | 0 | (ULEB128) | throw() | | |
| | +---------------------------------------+------------------------------------------+ | |
| | ... | |
| | +---------------------------------------+------------------------------------------+ | |
| | | 1st ttypeIndex for Nth exception spec | (ULEB128) | | | |
| | | ... | (ULEB128) | | | |
| | | Mth ttypeIndex for Nth exception spec | (ULEB128) | | | |
| | | 0 | (ULEB128) | | | |
| | +---------------------------------------+------------------------------------------+ | |
| +---------------------------------------------------------------------------------------+ |
| |
| Notes: |
| |
| * ttypeIndex in the Action Table, and in the exception spec table, is an index, |
| not a byte count, if positive. It is a negative index offset of |
| classInfoOffset and the sizeof entry depends on ttypeEncoding. |
| But if ttypeIndex is negative, it is a positive 1-based byte offset into the |
| type_info Table. |
| And if ttypeIndex is zero, it refers to a catch (...). |
| |
| * landingPad can be 0, this implies there is nothing to be done. |
| |
| * landingPad != 0 and actionEntry == 0 implies a cleanup needs to be done |
| @landingPad. |
| |
| * A cleanup can also be found under landingPad != 0 and actionEntry != 0 in |
| the Action Table with ttypeIndex == 0. |
| */ |
| |
| namespace __cxxabiv1 |
| { |
| |
| namespace |
| { |
| |
| template <class AsType> |
| uintptr_t readPointerHelper(const uint8_t*& p) { |
| AsType value; |
| memcpy(&value, p, sizeof(AsType)); |
| p += sizeof(AsType); |
| return static_cast<uintptr_t>(value); |
| } |
| |
| } // end namespace |
| |
| extern "C" |
| { |
| |
| // private API |
| |
| // Heavily borrowed from llvm/examples/ExceptionDemo/ExceptionDemo.cpp |
| |
| // DWARF Constants |
| enum |
| { |
| DW_EH_PE_absptr = 0x00, |
| DW_EH_PE_uleb128 = 0x01, |
| DW_EH_PE_udata2 = 0x02, |
| DW_EH_PE_udata4 = 0x03, |
| DW_EH_PE_udata8 = 0x04, |
| DW_EH_PE_sleb128 = 0x09, |
| DW_EH_PE_sdata2 = 0x0A, |
| DW_EH_PE_sdata4 = 0x0B, |
| DW_EH_PE_sdata8 = 0x0C, |
| DW_EH_PE_pcrel = 0x10, |
| DW_EH_PE_textrel = 0x20, |
| DW_EH_PE_datarel = 0x30, |
| DW_EH_PE_funcrel = 0x40, |
| DW_EH_PE_aligned = 0x50, |
| DW_EH_PE_indirect = 0x80, |
| DW_EH_PE_omit = 0xFF |
| }; |
| |
| /// Read a uleb128 encoded value and advance pointer |
| /// See Variable Length Data Appendix C in: |
| /// @link http://dwarfstd.org/Dwarf4.pdf @unlink |
| /// @param data reference variable holding memory pointer to decode from |
| /// @returns decoded value |
| static |
| uintptr_t |
| readULEB128(const uint8_t** data) |
| { |
| uintptr_t result = 0; |
| uintptr_t shift = 0; |
| unsigned char byte; |
| const uint8_t *p = *data; |
| do |
| { |
| byte = *p++; |
| result |= static_cast<uintptr_t>(byte & 0x7F) << shift; |
| shift += 7; |
| } while (byte & 0x80); |
| *data = p; |
| return result; |
| } |
| |
| /// Read a sleb128 encoded value and advance pointer |
| /// See Variable Length Data Appendix C in: |
| /// @link http://dwarfstd.org/Dwarf4.pdf @unlink |
| /// @param data reference variable holding memory pointer to decode from |
| /// @returns decoded value |
| static |
| intptr_t |
| readSLEB128(const uint8_t** data) |
| { |
| uintptr_t result = 0; |
| uintptr_t shift = 0; |
| unsigned char byte; |
| const uint8_t *p = *data; |
| do |
| { |
| byte = *p++; |
| result |= static_cast<uintptr_t>(byte & 0x7F) << shift; |
| shift += 7; |
| } while (byte & 0x80); |
| *data = p; |
| if ((byte & 0x40) && (shift < (sizeof(result) << 3))) |
| result |= static_cast<uintptr_t>(~0) << shift; |
| return static_cast<intptr_t>(result); |
| } |
| |
| /// Read a pointer encoded value and advance pointer |
| /// See Variable Length Data in: |
| /// @link http://dwarfstd.org/Dwarf3.pdf @unlink |
| /// @param data reference variable holding memory pointer to decode from |
| /// @param encoding dwarf encoding type |
| /// @returns decoded value |
| static |
| uintptr_t |
| readEncodedPointer(const uint8_t** data, uint8_t encoding) |
| { |
| uintptr_t result = 0; |
| if (encoding == DW_EH_PE_omit) |
| return result; |
| const uint8_t* p = *data; |
| // first get value |
| switch (encoding & 0x0F) |
| { |
| case DW_EH_PE_absptr: |
| result = readPointerHelper<uintptr_t>(p); |
| break; |
| case DW_EH_PE_uleb128: |
| result = readULEB128(&p); |
| break; |
| case DW_EH_PE_sleb128: |
| result = static_cast<uintptr_t>(readSLEB128(&p)); |
| break; |
| case DW_EH_PE_udata2: |
| result = readPointerHelper<uint16_t>(p); |
| break; |
| case DW_EH_PE_udata4: |
| result = readPointerHelper<uint32_t>(p); |
| break; |
| case DW_EH_PE_udata8: |
| result = readPointerHelper<uint64_t>(p); |
| break; |
| case DW_EH_PE_sdata2: |
| result = readPointerHelper<int16_t>(p); |
| break; |
| case DW_EH_PE_sdata4: |
| result = readPointerHelper<int32_t>(p); |
| break; |
| case DW_EH_PE_sdata8: |
| result = readPointerHelper<int64_t>(p); |
| break; |
| default: |
| // not supported |
| abort(); |
| break; |
| } |
| // then add relative offset |
| switch (encoding & 0x70) |
| { |
| case DW_EH_PE_absptr: |
| // do nothing |
| break; |
| case DW_EH_PE_pcrel: |
| if (result) |
| result += (uintptr_t)(*data); |
| break; |
| case DW_EH_PE_textrel: |
| case DW_EH_PE_datarel: |
| case DW_EH_PE_funcrel: |
| case DW_EH_PE_aligned: |
| default: |
| // not supported |
| abort(); |
| break; |
| } |
| // then apply indirection |
| if (result && (encoding & DW_EH_PE_indirect)) |
| result = *((uintptr_t*)result); |
| *data = p; |
| return result; |
| } |
| |
| static |
| void |
| call_terminate(bool native_exception, _Unwind_Exception* unwind_exception) |
| { |
| __cxa_begin_catch(unwind_exception); |
| if (native_exception) |
| { |
| // Use the stored terminate_handler if possible |
| __cxa_exception* exception_header = (__cxa_exception*)(unwind_exception+1) - 1; |
| std::__terminate(exception_header->terminateHandler); |
| } |
| std::terminate(); |
| } |
| |
| #if defined(_LIBCXXABI_ARM_EHABI) |
| static const void* read_target2_value(const void* ptr) |
| { |
| uintptr_t offset = *reinterpret_cast<const uintptr_t*>(ptr); |
| if (!offset) |
| return 0; |
| // "ARM EABI provides a TARGET2 relocation to describe these typeinfo |
| // pointers. The reason being it allows their precise semantics to be |
| // deferred to the linker. For bare-metal they turn into absolute |
| // relocations. For linux they turn into GOT-REL relocations." |
| // https://gcc.gnu.org/ml/gcc-patches/2009-08/msg00264.html |
| #if defined(LIBCXXABI_BAREMETAL) |
| return reinterpret_cast<const void*>(reinterpret_cast<uintptr_t>(ptr) + |
| offset); |
| #else |
| return *reinterpret_cast<const void **>(reinterpret_cast<uintptr_t>(ptr) + |
| offset); |
| #endif |
| } |
| |
| static const __shim_type_info* |
| get_shim_type_info(uint64_t ttypeIndex, const uint8_t* classInfo, |
| uint8_t ttypeEncoding, bool native_exception, |
| _Unwind_Exception* unwind_exception) |
| { |
| if (classInfo == 0) |
| { |
| // this should not happen. Indicates corrupted eh_table. |
| call_terminate(native_exception, unwind_exception); |
| } |
| |
| assert(((ttypeEncoding == DW_EH_PE_absptr) || // LLVM or GCC 4.6 |
| (ttypeEncoding == DW_EH_PE_pcrel) || // GCC 4.7 baremetal |
| (ttypeEncoding == (DW_EH_PE_pcrel | DW_EH_PE_indirect))) && // GCC 4.7 linux |
| "Unexpected TTypeEncoding"); |
| (void)ttypeEncoding; |
| |
| const uint8_t* ttypePtr = classInfo - ttypeIndex * sizeof(uintptr_t); |
| return reinterpret_cast<const __shim_type_info *>( |
| read_target2_value(ttypePtr)); |
| } |
| #else // !defined(_LIBCXXABI_ARM_EHABI) |
| static |
| const __shim_type_info* |
| get_shim_type_info(uint64_t ttypeIndex, const uint8_t* classInfo, |
| uint8_t ttypeEncoding, bool native_exception, |
| _Unwind_Exception* unwind_exception) |
| { |
| if (classInfo == 0) |
| { |
| // this should not happen. Indicates corrupted eh_table. |
| call_terminate(native_exception, unwind_exception); |
| } |
| switch (ttypeEncoding & 0x0F) |
| { |
| case DW_EH_PE_absptr: |
| ttypeIndex *= sizeof(void*); |
| break; |
| case DW_EH_PE_udata2: |
| case DW_EH_PE_sdata2: |
| ttypeIndex *= 2; |
| break; |
| case DW_EH_PE_udata4: |
| case DW_EH_PE_sdata4: |
| ttypeIndex *= 4; |
| break; |
| case DW_EH_PE_udata8: |
| case DW_EH_PE_sdata8: |
| ttypeIndex *= 8; |
| break; |
| default: |
| // this should not happen. Indicates corrupted eh_table. |
| call_terminate(native_exception, unwind_exception); |
| } |
| classInfo -= ttypeIndex; |
| return (const __shim_type_info*)readEncodedPointer(&classInfo, ttypeEncoding); |
| } |
| #endif // !defined(_LIBCXXABI_ARM_EHABI) |
| |
| /* |
| This is checking a thrown exception type, excpType, against a possibly empty |
| list of catchType's which make up an exception spec. |
| |
| An exception spec acts like a catch handler, but in reverse. This "catch |
| handler" will catch an excpType if and only if none of the catchType's in |
| the list will catch a excpType. If any catchType in the list can catch an |
| excpType, then this exception spec does not catch the excpType. |
| */ |
| #if defined(_LIBCXXABI_ARM_EHABI) |
| static |
| bool |
| exception_spec_can_catch(int64_t specIndex, const uint8_t* classInfo, |
| uint8_t ttypeEncoding, const __shim_type_info* excpType, |
| void* adjustedPtr, _Unwind_Exception* unwind_exception) |
| { |
| if (classInfo == 0) |
| { |
| // this should not happen. Indicates corrupted eh_table. |
| call_terminate(false, unwind_exception); |
| } |
| |
| assert(((ttypeEncoding == DW_EH_PE_absptr) || // LLVM or GCC 4.6 |
| (ttypeEncoding == DW_EH_PE_pcrel) || // GCC 4.7 baremetal |
| (ttypeEncoding == (DW_EH_PE_pcrel | DW_EH_PE_indirect))) && // GCC 4.7 linux |
| "Unexpected TTypeEncoding"); |
| (void)ttypeEncoding; |
| |
| // specIndex is negative of 1-based byte offset into classInfo; |
| specIndex = -specIndex; |
| --specIndex; |
| const void** temp = reinterpret_cast<const void**>( |
| reinterpret_cast<uintptr_t>(classInfo) + |
| static_cast<uintptr_t>(specIndex) * sizeof(uintptr_t)); |
| // If any type in the spec list can catch excpType, return false, else return true |
| // adjustments to adjustedPtr are ignored. |
| while (true) |
| { |
| // ARM EHABI exception specification table (filter table) consists of |
| // several pointers which will directly point to the type info object |
| // (instead of ttypeIndex). The table will be terminated with 0. |
| const void** ttypePtr = temp++; |
| if (*ttypePtr == 0) |
| break; |
| // We can get the __shim_type_info simply by performing a |
| // R_ARM_TARGET2 relocation, and cast the result to __shim_type_info. |
| const __shim_type_info* catchType = |
| static_cast<const __shim_type_info*>(read_target2_value(ttypePtr)); |
| void* tempPtr = adjustedPtr; |
| if (catchType->can_catch(excpType, tempPtr)) |
| return false; |
| } |
| return true; |
| } |
| #else |
| static |
| bool |
| exception_spec_can_catch(int64_t specIndex, const uint8_t* classInfo, |
| uint8_t ttypeEncoding, const __shim_type_info* excpType, |
| void* adjustedPtr, _Unwind_Exception* unwind_exception) |
| { |
| if (classInfo == 0) |
| { |
| // this should not happen. Indicates corrupted eh_table. |
| call_terminate(false, unwind_exception); |
| } |
| // specIndex is negative of 1-based byte offset into classInfo; |
| specIndex = -specIndex; |
| --specIndex; |
| const uint8_t* temp = classInfo + specIndex; |
| // If any type in the spec list can catch excpType, return false, else return true |
| // adjustments to adjustedPtr are ignored. |
| while (true) |
| { |
| uint64_t ttypeIndex = readULEB128(&temp); |
| if (ttypeIndex == 0) |
| break; |
| const __shim_type_info* catchType = get_shim_type_info(ttypeIndex, |
| classInfo, |
| ttypeEncoding, |
| true, |
| unwind_exception); |
| void* tempPtr = adjustedPtr; |
| if (catchType->can_catch(excpType, tempPtr)) |
| return false; |
| } |
| return true; |
| } |
| #endif |
| |
| static |
| void* |
| get_thrown_object_ptr(_Unwind_Exception* unwind_exception) |
| { |
| // Even for foreign exceptions, the exception object is *probably* at unwind_exception + 1 |
| // Regardless, this library is prohibited from touching a foreign exception |
| void* adjustedPtr = unwind_exception + 1; |
| if (unwind_exception->exception_class == kOurDependentExceptionClass) |
| adjustedPtr = ((__cxa_dependent_exception*)adjustedPtr - 1)->primaryException; |
| return adjustedPtr; |
| } |
| |
| namespace |
| { |
| |
| struct scan_results |
| { |
| int64_t ttypeIndex; // > 0 catch handler, < 0 exception spec handler, == 0 a cleanup |
| const uint8_t* actionRecord; // Currently unused. Retained to ease future maintenance. |
| const uint8_t* languageSpecificData; // Needed only for __cxa_call_unexpected |
| uintptr_t landingPad; // null -> nothing found, else something found |
| void* adjustedPtr; // Used in cxa_exception.cpp |
| _Unwind_Reason_Code reason; // One of _URC_FATAL_PHASE1_ERROR, |
| // _URC_FATAL_PHASE2_ERROR, |
| // _URC_CONTINUE_UNWIND, |
| // _URC_HANDLER_FOUND |
| }; |
| |
| } // unnamed namespace |
| |
| static |
| void |
| set_registers(_Unwind_Exception* unwind_exception, _Unwind_Context* context, |
| const scan_results& results) |
| { |
| #if defined(__USING_SJLJ_EXCEPTIONS__) |
| #define __builtin_eh_return_data_regno(regno) regno |
| #endif |
| _Unwind_SetGR(context, __builtin_eh_return_data_regno(0), |
| reinterpret_cast<uintptr_t>(unwind_exception)); |
| _Unwind_SetGR(context, __builtin_eh_return_data_regno(1), |
| static_cast<uintptr_t>(results.ttypeIndex)); |
| _Unwind_SetIP(context, results.landingPad); |
| } |
| |
| /* |
| There are 3 types of scans needed: |
| |
| 1. Scan for handler with native or foreign exception. If handler found, |
| save state and return _URC_HANDLER_FOUND, else return _URC_CONTINUE_UNWIND. |
| May also report an error on invalid input. |
| May terminate for invalid exception table. |
| _UA_SEARCH_PHASE |
| |
| 2. Scan for handler with foreign exception. Must return _URC_HANDLER_FOUND, |
| or call terminate. |
| _UA_CLEANUP_PHASE && _UA_HANDLER_FRAME && !native_exception |
| |
| 3. Scan for cleanups. If a handler is found and this isn't forced unwind, |
| then terminate, otherwise ignore the handler and keep looking for cleanup. |
| If a cleanup is found, return _URC_HANDLER_FOUND, else return _URC_CONTINUE_UNWIND. |
| May also report an error on invalid input. |
| May terminate for invalid exception table. |
| _UA_CLEANUP_PHASE && !_UA_HANDLER_FRAME |
| */ |
| |
| static void scan_eh_tab(scan_results &results, _Unwind_Action actions, |
| bool native_exception, |
| _Unwind_Exception *unwind_exception, |
| _Unwind_Context *context) { |
| // Initialize results to found nothing but an error |
| results.ttypeIndex = 0; |
| results.actionRecord = 0; |
| results.languageSpecificData = 0; |
| results.landingPad = 0; |
| results.adjustedPtr = 0; |
| results.reason = _URC_FATAL_PHASE1_ERROR; |
| // Check for consistent actions |
| if (actions & _UA_SEARCH_PHASE) |
| { |
| // Do Phase 1 |
| if (actions & (_UA_CLEANUP_PHASE | _UA_HANDLER_FRAME | _UA_FORCE_UNWIND)) |
| { |
| // None of these flags should be set during Phase 1 |
| // Client error |
| results.reason = _URC_FATAL_PHASE1_ERROR; |
| return; |
| } |
| } |
| else if (actions & _UA_CLEANUP_PHASE) |
| { |
| if ((actions & _UA_HANDLER_FRAME) && (actions & _UA_FORCE_UNWIND)) |
| { |
| // _UA_HANDLER_FRAME should only be set if phase 1 found a handler. |
| // If _UA_FORCE_UNWIND is set, phase 1 shouldn't have happened. |
| // Client error |
| results.reason = _URC_FATAL_PHASE2_ERROR; |
| return; |
| } |
| } |
| else // Neither _UA_SEARCH_PHASE nor _UA_CLEANUP_PHASE is set |
| { |
| // One of these should be set. |
| // Client error |
| results.reason = _URC_FATAL_PHASE1_ERROR; |
| return; |
| } |
| // Start scan by getting exception table address |
| const uint8_t *lsda = (const uint8_t *)_Unwind_GetLanguageSpecificData(context); |
| if (lsda == 0) |
| { |
| // There is no exception table |
| results.reason = _URC_CONTINUE_UNWIND; |
| return; |
| } |
| results.languageSpecificData = lsda; |
| // Get the current instruction pointer and offset it before next |
| // instruction in the current frame which threw the exception. |
| uintptr_t ip = _Unwind_GetIP(context) - 1; |
| // Get beginning current frame's code (as defined by the |
| // emitted dwarf code) |
| uintptr_t funcStart = _Unwind_GetRegionStart(context); |
| #ifdef __USING_SJLJ_EXCEPTIONS__ |
| if (ip == uintptr_t(-1)) |
| { |
| // no action |
| results.reason = _URC_CONTINUE_UNWIND; |
| return; |
| } |
| else if (ip == 0) |
| call_terminate(native_exception, unwind_exception); |
| // ip is 1-based index into call site table |
| #else // !__USING_SJLJ_EXCEPTIONS__ |
| uintptr_t ipOffset = ip - funcStart; |
| #endif // !defined(_USING_SLJL_EXCEPTIONS__) |
| const uint8_t* classInfo = NULL; |
| // Note: See JITDwarfEmitter::EmitExceptionTable(...) for corresponding |
| // dwarf emission |
| // Parse LSDA header. |
| uint8_t lpStartEncoding = *lsda++; |
| const uint8_t* lpStart = (const uint8_t*)readEncodedPointer(&lsda, lpStartEncoding); |
| if (lpStart == 0) |
| lpStart = (const uint8_t*)funcStart; |
| uint8_t ttypeEncoding = *lsda++; |
| if (ttypeEncoding != DW_EH_PE_omit) |
| { |
| // Calculate type info locations in emitted dwarf code which |
| // were flagged by type info arguments to llvm.eh.selector |
| // intrinsic |
| uintptr_t classInfoOffset = readULEB128(&lsda); |
| classInfo = lsda + classInfoOffset; |
| } |
| // Walk call-site table looking for range that |
| // includes current PC. |
| uint8_t callSiteEncoding = *lsda++; |
| #ifdef __USING_SJLJ_EXCEPTIONS__ |
| (void)callSiteEncoding; // When using SjLj exceptions, callSiteEncoding is never used |
| #endif |
| uint32_t callSiteTableLength = static_cast<uint32_t>(readULEB128(&lsda)); |
| const uint8_t* callSiteTableStart = lsda; |
| const uint8_t* callSiteTableEnd = callSiteTableStart + callSiteTableLength; |
| const uint8_t* actionTableStart = callSiteTableEnd; |
| const uint8_t* callSitePtr = callSiteTableStart; |
| while (callSitePtr < callSiteTableEnd) |
| { |
| // There is one entry per call site. |
| #ifndef __USING_SJLJ_EXCEPTIONS__ |
| // The call sites are non-overlapping in [start, start+length) |
| // The call sites are ordered in increasing value of start |
| uintptr_t start = readEncodedPointer(&callSitePtr, callSiteEncoding); |
| uintptr_t length = readEncodedPointer(&callSitePtr, callSiteEncoding); |
| uintptr_t landingPad = readEncodedPointer(&callSitePtr, callSiteEncoding); |
| uintptr_t actionEntry = readULEB128(&callSitePtr); |
| if ((start <= ipOffset) && (ipOffset < (start + length))) |
| #else // __USING_SJLJ_EXCEPTIONS__ |
| // ip is 1-based index into this table |
| uintptr_t landingPad = readULEB128(&callSitePtr); |
| uintptr_t actionEntry = readULEB128(&callSitePtr); |
| if (--ip == 0) |
| #endif // __USING_SJLJ_EXCEPTIONS__ |
| { |
| // Found the call site containing ip. |
| #ifndef __USING_SJLJ_EXCEPTIONS__ |
| if (landingPad == 0) |
| { |
| // No handler here |
| results.reason = _URC_CONTINUE_UNWIND; |
| return; |
| } |
| landingPad = (uintptr_t)lpStart + landingPad; |
| #else // __USING_SJLJ_EXCEPTIONS__ |
| ++landingPad; |
| #endif // __USING_SJLJ_EXCEPTIONS__ |
| if (actionEntry == 0) |
| { |
| // Found a cleanup |
| // If this is a type 1 or type 2 search, there are no handlers |
| // If this is a type 3 search, you want to install the cleanup. |
| if ((actions & _UA_CLEANUP_PHASE) && !(actions & _UA_HANDLER_FRAME)) |
| { |
| results.ttypeIndex = 0; // Redundant but clarifying |
| results.landingPad = landingPad; |
| results.reason = _URC_HANDLER_FOUND; |
| return; |
| } |
| // No handler here |
| results.reason = _URC_CONTINUE_UNWIND; |
| return; |
| } |
| // Convert 1-based byte offset into |
| const uint8_t* action = actionTableStart + (actionEntry - 1); |
| // Scan action entries until you find a matching handler, cleanup, or the end of action list |
| while (true) |
| { |
| const uint8_t* actionRecord = action; |
| int64_t ttypeIndex = readSLEB128(&action); |
| if (ttypeIndex > 0) |
| { |
| // Found a catch, does it actually catch? |
| // First check for catch (...) |
| const __shim_type_info* catchType = |
| get_shim_type_info(static_cast<uint64_t>(ttypeIndex), |
| classInfo, ttypeEncoding, |
| native_exception, unwind_exception); |
| if (catchType == 0) |
| { |
| // Found catch (...) catches everything, including foreign exceptions |
| // If this is a type 1 search save state and return _URC_HANDLER_FOUND |
| // If this is a type 2 search save state and return _URC_HANDLER_FOUND |
| // If this is a type 3 search !_UA_FORCE_UNWIND, we should have found this in phase 1! |
| // If this is a type 3 search _UA_FORCE_UNWIND, ignore handler and continue scan |
| if ((actions & _UA_SEARCH_PHASE) || (actions & _UA_HANDLER_FRAME)) |
| { |
| // Save state and return _URC_HANDLER_FOUND |
| results.ttypeIndex = ttypeIndex; |
| results.actionRecord = actionRecord; |
| results.landingPad = landingPad; |
| results.adjustedPtr = get_thrown_object_ptr(unwind_exception); |
| results.reason = _URC_HANDLER_FOUND; |
| return; |
| } |
| else if (!(actions & _UA_FORCE_UNWIND)) |
| { |
| // It looks like the exception table has changed |
| // on us. Likely stack corruption! |
| call_terminate(native_exception, unwind_exception); |
| } |
| } |
| // Else this is a catch (T) clause and will never |
| // catch a foreign exception |
| else if (native_exception) |
| { |
| __cxa_exception* exception_header = (__cxa_exception*)(unwind_exception+1) - 1; |
| void* adjustedPtr = get_thrown_object_ptr(unwind_exception); |
| const __shim_type_info* excpType = |
| static_cast<const __shim_type_info*>(exception_header->exceptionType); |
| if (adjustedPtr == 0 || excpType == 0) |
| { |
| // Something very bad happened |
| call_terminate(native_exception, unwind_exception); |
| } |
| if (catchType->can_catch(excpType, adjustedPtr)) |
| { |
| // Found a matching handler |
| // If this is a type 1 search save state and return _URC_HANDLER_FOUND |
| // If this is a type 3 search and !_UA_FORCE_UNWIND, we should have found this in phase 1! |
| // If this is a type 3 search and _UA_FORCE_UNWIND, ignore handler and continue scan |
| if (actions & _UA_SEARCH_PHASE) |
| { |
| // Save state and return _URC_HANDLER_FOUND |
| results.ttypeIndex = ttypeIndex; |
| results.actionRecord = actionRecord; |
| results.landingPad = landingPad; |
| results.adjustedPtr = adjustedPtr; |
| results.reason = _URC_HANDLER_FOUND; |
| return; |
| } |
| else if (!(actions & _UA_FORCE_UNWIND)) |
| { |
| // It looks like the exception table has changed |
| // on us. Likely stack corruption! |
| call_terminate(native_exception, unwind_exception); |
| } |
| } |
| } |
| // Scan next action ... |
| } |
| else if (ttypeIndex < 0) |
| { |
| // Found an exception spec. If this is a foreign exception, |
| // it is always caught. |
| if (native_exception) |
| { |
| // Does the exception spec catch this native exception? |
| __cxa_exception* exception_header = (__cxa_exception*)(unwind_exception+1) - 1; |
| void* adjustedPtr = get_thrown_object_ptr(unwind_exception); |
| const __shim_type_info* excpType = |
| static_cast<const __shim_type_info*>(exception_header->exceptionType); |
| if (adjustedPtr == 0 || excpType == 0) |
| { |
| // Something very bad happened |
| call_terminate(native_exception, unwind_exception); |
| } |
| if (exception_spec_can_catch(ttypeIndex, classInfo, |
| ttypeEncoding, excpType, |
| adjustedPtr, unwind_exception)) |
| { |
| // native exception caught by exception spec |
| // If this is a type 1 search, save state and return _URC_HANDLER_FOUND |
| // If this is a type 3 search !_UA_FORCE_UNWIND, we should have found this in phase 1! |
| // If this is a type 3 search _UA_FORCE_UNWIND, ignore handler and continue scan |
| if (actions & _UA_SEARCH_PHASE) |
| { |
| // Save state and return _URC_HANDLER_FOUND |
| results.ttypeIndex = ttypeIndex; |
| results.actionRecord = actionRecord; |
| results.landingPad = landingPad; |
| results.adjustedPtr = adjustedPtr; |
| results.reason = _URC_HANDLER_FOUND; |
| return; |
| } |
| else if (!(actions & _UA_FORCE_UNWIND)) |
| { |
| // It looks like the exception table has changed |
| // on us. Likely stack corruption! |
| call_terminate(native_exception, unwind_exception); |
| } |
| } |
| } |
| else |
| { |
| // foreign exception caught by exception spec |
| // If this is a type 1 search, save state and return _URC_HANDLER_FOUND |
| // If this is a type 2 search, save state and return _URC_HANDLER_FOUND |
| // If this is a type 3 search !_UA_FORCE_UNWIND, we should have found this in phase 1! |
| // If this is a type 3 search _UA_FORCE_UNWIND, ignore handler and continue scan |
| if ((actions & _UA_SEARCH_PHASE) || (actions & _UA_HANDLER_FRAME)) |
| { |
| // Save state and return _URC_HANDLER_FOUND |
| results.ttypeIndex = ttypeIndex; |
| results.actionRecord = actionRecord; |
| results.landingPad = landingPad; |
| results.adjustedPtr = get_thrown_object_ptr(unwind_exception); |
| results.reason = _URC_HANDLER_FOUND; |
| return; |
| } |
| else if (!(actions & _UA_FORCE_UNWIND)) |
| { |
| // It looks like the exception table has changed |
| // on us. Likely stack corruption! |
| call_terminate(native_exception, unwind_exception); |
| } |
| } |
| // Scan next action ... |
| } |
| else // ttypeIndex == 0 |
| { |
| // Found a cleanup |
| // If this is a type 1 search, ignore it and continue scan |
| // If this is a type 2 search, ignore it and continue scan |
| // If this is a type 3 search, save state and return _URC_HANDLER_FOUND |
| if ((actions & _UA_CLEANUP_PHASE) && !(actions & _UA_HANDLER_FRAME)) |
| { |
| // Save state and return _URC_HANDLER_FOUND |
| results.ttypeIndex = ttypeIndex; |
| results.actionRecord = actionRecord; |
| results.landingPad = landingPad; |
| results.adjustedPtr = get_thrown_object_ptr(unwind_exception); |
| results.reason = _URC_HANDLER_FOUND; |
| return; |
| } |
| } |
| const uint8_t* temp = action; |
| int64_t actionOffset = readSLEB128(&temp); |
| if (actionOffset == 0) |
| { |
| // End of action list, no matching handler or cleanup found |
| results.reason = _URC_CONTINUE_UNWIND; |
| return; |
| } |
| // Go to next action |
| action += actionOffset; |
| } // there is no break out of this loop, only return |
| } |
| #ifndef __USING_SJLJ_EXCEPTIONS__ |
| else if (ipOffset < start) |
| { |
| // There is no call site for this ip |
| // Something bad has happened. We should never get here. |
| // Possible stack corruption. |
| call_terminate(native_exception, unwind_exception); |
| } |
| #endif // !__USING_SJLJ_EXCEPTIONS__ |
| } // there might be some tricky cases which break out of this loop |
| |
| // It is possible that no eh table entry specify how to handle |
| // this exception. By spec, terminate it immediately. |
| call_terminate(native_exception, unwind_exception); |
| } |
| |
| // public API |
| |
| /* |
| The personality function branches on actions like so: |
| |
| _UA_SEARCH_PHASE |
| |
| If _UA_CLEANUP_PHASE or _UA_HANDLER_FRAME or _UA_FORCE_UNWIND there's |
| an error from above, return _URC_FATAL_PHASE1_ERROR. |
| |
| Scan for anything that could stop unwinding: |
| |
| 1. A catch clause that will catch this exception |
| (will never catch foreign). |
| 2. A catch (...) (will always catch foreign). |
| 3. An exception spec that will catch this exception |
| (will always catch foreign). |
| If a handler is found |
| If not foreign |
| Save state in header |
| return _URC_HANDLER_FOUND |
| Else a handler not found |
| return _URC_CONTINUE_UNWIND |
| |
| _UA_CLEANUP_PHASE |
| |
| If _UA_HANDLER_FRAME |
| If _UA_FORCE_UNWIND |
| How did this happen? return _URC_FATAL_PHASE2_ERROR |
| If foreign |
| Do _UA_SEARCH_PHASE to recover state |
| else |
| Recover state from header |
| Transfer control to landing pad. return _URC_INSTALL_CONTEXT |
| |
| Else |
| |
| This branch handles both normal C++ non-catching handlers (cleanups) |
| and forced unwinding. |
| Scan for anything that can not stop unwinding: |
| |
| 1. A cleanup. |
| |
| If a cleanup is found |
| transfer control to it. return _URC_INSTALL_CONTEXT |
| Else a cleanup is not found: return _URC_CONTINUE_UNWIND |
| */ |
| |
| #if !defined(_LIBCXXABI_ARM_EHABI) |
| #if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__) |
| static _Unwind_Reason_Code __gxx_personality_imp |
| #else |
| _LIBCXXABI_FUNC_VIS _Unwind_Reason_Code |
| #ifdef __USING_SJLJ_EXCEPTIONS__ |
| __gxx_personality_sj0 |
| #else |
| __gxx_personality_v0 |
| #endif |
| #endif |
| (int version, _Unwind_Action actions, uint64_t exceptionClass, |
| _Unwind_Exception* unwind_exception, _Unwind_Context* context) |
| { |
| if (version != 1 || unwind_exception == 0 || context == 0) |
| return _URC_FATAL_PHASE1_ERROR; |
| |
| bool native_exception = (exceptionClass & get_vendor_and_language) == |
| (kOurExceptionClass & get_vendor_and_language); |
| scan_results results; |
| if (actions & _UA_SEARCH_PHASE) |
| { |
| // Phase 1 search: All we're looking for in phase 1 is a handler that |
| // halts unwinding |
| scan_eh_tab(results, actions, native_exception, unwind_exception, context); |
| if (results.reason == _URC_HANDLER_FOUND) |
| { |
| // Found one. Can we cache the results somewhere to optimize phase 2? |
| if (native_exception) |
| { |
| __cxa_exception* exception_header = (__cxa_exception*)(unwind_exception+1) - 1; |
| exception_header->handlerSwitchValue = static_cast<int>(results.ttypeIndex); |
| exception_header->actionRecord = results.actionRecord; |
| exception_header->languageSpecificData = results.languageSpecificData; |
| exception_header->catchTemp = reinterpret_cast<void*>(results.landingPad); |
| exception_header->adjustedPtr = results.adjustedPtr; |
| } |
| return _URC_HANDLER_FOUND; |
| } |
| // Did not find a catching-handler. Return the results of the scan |
| // (normally _URC_CONTINUE_UNWIND, but could have been _URC_FATAL_PHASE1_ERROR |
| // if we were called improperly). |
| return results.reason; |
| } |
| if (actions & _UA_CLEANUP_PHASE) |
| { |
| // Phase 2 search: |
| // Did we find a catching handler in phase 1? |
| if (actions & _UA_HANDLER_FRAME) |
| { |
| // Yes, phase 1 said we have a catching handler here. |
| // Did we cache the results of the scan? |
| if (native_exception) |
| { |
| // Yes, reload the results from the cache. |
| __cxa_exception* exception_header = (__cxa_exception*)(unwind_exception+1) - 1; |
| results.ttypeIndex = exception_header->handlerSwitchValue; |
| results.actionRecord = exception_header->actionRecord; |
| results.languageSpecificData = exception_header->languageSpecificData; |
| results.landingPad = reinterpret_cast<uintptr_t>(exception_header->catchTemp); |
| results.adjustedPtr = exception_header->adjustedPtr; |
| } |
| else |
| { |
| // No, do the scan again to reload the results. |
| scan_eh_tab(results, actions, native_exception, unwind_exception, context); |
| // Phase 1 told us we would find a handler. Now in Phase 2 we |
| // didn't find a handler. The eh table should not be changing! |
| if (results.reason != _URC_HANDLER_FOUND) |
| call_terminate(native_exception, unwind_exception); |
| } |
| // Jump to the handler |
| set_registers(unwind_exception, context, results); |
| return _URC_INSTALL_CONTEXT; |
| } |
| // Either we didn't do a phase 1 search (due to forced unwinding), or |
| // phase 1 reported no catching-handlers. |
| // Search for a (non-catching) cleanup |
| scan_eh_tab(results, actions, native_exception, unwind_exception, context); |
| if (results.reason == _URC_HANDLER_FOUND) |
| { |
| // Found a non-catching handler. Jump to it: |
| set_registers(unwind_exception, context, results); |
| return _URC_INSTALL_CONTEXT; |
| } |
| // Did not find a cleanup. Return the results of the scan |
| // (normally _URC_CONTINUE_UNWIND, but could have been _URC_FATAL_PHASE2_ERROR |
| // if we were called improperly). |
| return results.reason; |
| } |
| // We were called improperly: neither a phase 1 or phase 2 search |
| return _URC_FATAL_PHASE1_ERROR; |
| } |
| |
| #if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__) |
| extern "C" EXCEPTION_DISPOSITION |
| __gxx_personality_seh0(PEXCEPTION_RECORD ms_exc, void *this_frame, |
| PCONTEXT ms_orig_context, PDISPATCHER_CONTEXT ms_disp) |
| { |
| return _GCC_specific_handler(ms_exc, this_frame, ms_orig_context, ms_disp, |
| __gxx_personality_imp); |
| } |
| #endif |
| |
| #else |
| |
| extern "C" _Unwind_Reason_Code __gnu_unwind_frame(_Unwind_Exception*, |
| _Unwind_Context*); |
| |
| // Helper function to unwind one frame. |
| // ARM EHABI 7.3 and 7.4: If the personality function returns _URC_CONTINUE_UNWIND, the |
| // personality routine should update the virtual register set (VRS) according to the |
| // corresponding frame unwinding instructions (ARM EHABI 9.3.) |
| static _Unwind_Reason_Code continue_unwind(_Unwind_Exception* unwind_exception, |
| _Unwind_Context* context) |
| { |
| if (__gnu_unwind_frame(unwind_exception, context) != _URC_OK) |
| return _URC_FAILURE; |
| return _URC_CONTINUE_UNWIND; |
| } |
| |
| // ARM register names |
| #if !defined(LIBCXXABI_USE_LLVM_UNWINDER) |
| static const uint32_t REG_UCB = 12; // Register to save _Unwind_Control_Block |
| #endif |
| static const uint32_t REG_SP = 13; |
| |
| static void save_results_to_barrier_cache(_Unwind_Exception* unwind_exception, |
| const scan_results& results) |
| { |
| unwind_exception->barrier_cache.bitpattern[0] = (uint32_t)results.adjustedPtr; |
| unwind_exception->barrier_cache.bitpattern[1] = (uint32_t)results.actionRecord; |
| unwind_exception->barrier_cache.bitpattern[2] = (uint32_t)results.languageSpecificData; |
| unwind_exception->barrier_cache.bitpattern[3] = (uint32_t)results.landingPad; |
| unwind_exception->barrier_cache.bitpattern[4] = (uint32_t)results.ttypeIndex; |
| } |
| |
| static void load_results_from_barrier_cache(scan_results& results, |
| const _Unwind_Exception* unwind_exception) |
| { |
| results.adjustedPtr = (void*)unwind_exception->barrier_cache.bitpattern[0]; |
| results.actionRecord = (const uint8_t*)unwind_exception->barrier_cache.bitpattern[1]; |
| results.languageSpecificData = (const uint8_t*)unwind_exception->barrier_cache.bitpattern[2]; |
| results.landingPad = (uintptr_t)unwind_exception->barrier_cache.bitpattern[3]; |
| results.ttypeIndex = (int64_t)(int32_t)unwind_exception->barrier_cache.bitpattern[4]; |
| } |
| |
| extern "C" _LIBCXXABI_FUNC_VIS _Unwind_Reason_Code |
| __gxx_personality_v0(_Unwind_State state, |
| _Unwind_Exception* unwind_exception, |
| _Unwind_Context* context) |
| { |
| if (unwind_exception == 0 || context == 0) |
| return _URC_FATAL_PHASE1_ERROR; |
| |
| bool native_exception = (unwind_exception->exception_class & get_vendor_and_language) == |
| (kOurExceptionClass & get_vendor_and_language); |
| |
| #if !defined(LIBCXXABI_USE_LLVM_UNWINDER) |
| // Copy the address of _Unwind_Control_Block to r12 so that |
| // _Unwind_GetLanguageSpecificData() and _Unwind_GetRegionStart() can |
| // return correct address. |
| _Unwind_SetGR(context, REG_UCB, reinterpret_cast<uint32_t>(unwind_exception)); |
| #endif |
| |
| // Check the undocumented force unwinding behavior |
| bool is_force_unwinding = state & _US_FORCE_UNWIND; |
| state &= ~_US_FORCE_UNWIND; |
| |
| scan_results results; |
| switch (state) { |
| case _US_VIRTUAL_UNWIND_FRAME: |
| if (is_force_unwinding) |
| return continue_unwind(unwind_exception, context); |
| |
| // Phase 1 search: All we're looking for in phase 1 is a handler that halts unwinding |
| scan_eh_tab(results, _UA_SEARCH_PHASE, native_exception, unwind_exception, context); |
| if (results.reason == _URC_HANDLER_FOUND) |
| { |
| unwind_exception->barrier_cache.sp = _Unwind_GetGR(context, REG_SP); |
| if (native_exception) |
| save_results_to_barrier_cache(unwind_exception, results); |
| return _URC_HANDLER_FOUND; |
| } |
| // Did not find the catch handler |
| if (results.reason == _URC_CONTINUE_UNWIND) |
| return continue_unwind(unwind_exception, context); |
| return results.reason; |
| |
| case _US_UNWIND_FRAME_STARTING: |
| // TODO: Support force unwinding in the phase 2 search. |
| // NOTE: In order to call the cleanup functions, _Unwind_ForcedUnwind() |
| // will call this personality function with (_US_FORCE_UNWIND | |
| // _US_UNWIND_FRAME_STARTING). |
| |
| // Phase 2 search |
| if (unwind_exception->barrier_cache.sp == _Unwind_GetGR(context, REG_SP)) |
| { |
| // Found a catching handler in phase 1 |
| if (native_exception) |
| { |
| // Load the result from the native exception barrier cache. |
| load_results_from_barrier_cache(results, unwind_exception); |
| results.reason = _URC_HANDLER_FOUND; |
| } |
| else |
| { |
| // Search for the catching handler again for the foreign exception. |
| scan_eh_tab(results, static_cast<_Unwind_Action>(_UA_CLEANUP_PHASE | _UA_HANDLER_FRAME), |
| native_exception, unwind_exception, context); |
| if (results.reason != _URC_HANDLER_FOUND) // phase1 search should guarantee to find one |
| call_terminate(native_exception, unwind_exception); |
| } |
| |
| // Install the context for the catching handler |
| set_registers(unwind_exception, context, results); |
| return _URC_INSTALL_CONTEXT; |
| } |
| |
| // Either we didn't do a phase 1 search (due to forced unwinding), or |
| // phase 1 reported no catching-handlers. |
| // Search for a (non-catching) cleanup |
| scan_eh_tab(results, _UA_CLEANUP_PHASE, native_exception, unwind_exception, context); |
| if (results.reason == _URC_HANDLER_FOUND) |
| { |
| // Found a non-catching handler |
| |
| // ARM EHABI 8.4.2: Before we can jump to the cleanup handler, we have to setup some |
| // internal data structures, so that __cxa_end_cleanup() can get unwind_exception from |
| // __cxa_get_globals(). |
| __cxa_begin_cleanup(unwind_exception); |
| |
| // Install the context for the cleanup handler |
| set_registers(unwind_exception, context, results); |
| return _URC_INSTALL_CONTEXT; |
| } |
| |
| // Did not find any handler |
| if (results.reason == _URC_CONTINUE_UNWIND) |
| return continue_unwind(unwind_exception, context); |
| return results.reason; |
| |
| case _US_UNWIND_FRAME_RESUME: |
| return continue_unwind(unwind_exception, context); |
| } |
| |
| // We were called improperly: neither a phase 1 or phase 2 search |
| return _URC_FATAL_PHASE1_ERROR; |
| } |
| #endif |
| |
| |
| __attribute__((noreturn)) |
| _LIBCXXABI_FUNC_VIS void |
| __cxa_call_unexpected(void* arg) |
| { |
| _Unwind_Exception* unwind_exception = static_cast<_Unwind_Exception*>(arg); |
| if (unwind_exception == 0) |
| call_terminate(false, unwind_exception); |
| __cxa_begin_catch(unwind_exception); |
| bool native_old_exception = |
| (unwind_exception->exception_class & get_vendor_and_language) == |
| (kOurExceptionClass & get_vendor_and_language); |
| std::unexpected_handler u_handler; |
| std::terminate_handler t_handler; |
| __cxa_exception* old_exception_header = 0; |
| int64_t ttypeIndex; |
| const uint8_t* lsda; |
| if (native_old_exception) |
| { |
| old_exception_header = (__cxa_exception*)(unwind_exception+1) - 1; |
| t_handler = old_exception_header->terminateHandler; |
| u_handler = old_exception_header->unexpectedHandler; |
| // If std::__unexpected(u_handler) rethrows the same exception, |
| // these values get overwritten by the rethrow. So save them now: |
| #if defined(_LIBCXXABI_ARM_EHABI) |
| ttypeIndex = (int64_t)(int32_t)unwind_exception->barrier_cache.bitpattern[4]; |
| lsda = (const uint8_t*)unwind_exception->barrier_cache.bitpattern[2]; |
| #else |
| ttypeIndex = old_exception_header->handlerSwitchValue; |
| lsda = old_exception_header->languageSpecificData; |
| #endif |
| } |
| else |
| { |
| t_handler = std::get_terminate(); |
| u_handler = std::get_unexpected(); |
| } |
| try |
| { |
| std::__unexpected(u_handler); |
| } |
| catch (...) |
| { |
| // If the old exception is foreign, then all we can do is terminate. |
| // We have no way to recover the needed old exception spec. There's |
| // no way to pass that information here. And the personality routine |
| // can't call us directly and do anything but terminate() if we throw |
| // from here. |
| if (native_old_exception) |
| { |
| // Have: |
| // old_exception_header->languageSpecificData |
| // old_exception_header->actionRecord |
| // Need |
| // const uint8_t* classInfo |
| // uint8_t ttypeEncoding |
| uint8_t lpStartEncoding = *lsda++; |
| const uint8_t* lpStart = (const uint8_t*)readEncodedPointer(&lsda, lpStartEncoding); |
| (void)lpStart; // purposefully unused. Just needed to increment lsda. |
| uint8_t ttypeEncoding = *lsda++; |
| if (ttypeEncoding == DW_EH_PE_omit) |
| std::__terminate(t_handler); |
| uintptr_t classInfoOffset = readULEB128(&lsda); |
| const uint8_t* classInfo = lsda + classInfoOffset; |
| // Is this new exception catchable by the exception spec at ttypeIndex? |
| // The answer is obviously yes if the new and old exceptions are the same exception |
| // If no |
| // throw; |
| __cxa_eh_globals* globals = __cxa_get_globals_fast(); |
| __cxa_exception* new_exception_header = globals->caughtExceptions; |
| if (new_exception_header == 0) |
| // This shouldn't be able to happen! |
| std::__terminate(t_handler); |
| bool native_new_exception = |
| (new_exception_header->unwindHeader.exception_class & get_vendor_and_language) == |
| (kOurExceptionClass & get_vendor_and_language); |
| void* adjustedPtr; |
| if (native_new_exception && (new_exception_header != old_exception_header)) |
| { |
| const __shim_type_info* excpType = |
| static_cast<const __shim_type_info*>(new_exception_header->exceptionType); |
| adjustedPtr = |
| new_exception_header->unwindHeader.exception_class == kOurDependentExceptionClass ? |
| ((__cxa_dependent_exception*)new_exception_header)->primaryException : |
| new_exception_header + 1; |
| if (!exception_spec_can_catch(ttypeIndex, classInfo, ttypeEncoding, |
| excpType, adjustedPtr, unwind_exception)) |
| { |
| // We need to __cxa_end_catch, but for the old exception, |
| // not the new one. This is a little tricky ... |
| // Disguise new_exception_header as a rethrown exception, but |
| // don't actually rethrow it. This means you can temporarily |
| // end the catch clause enclosing new_exception_header without |
| // __cxa_end_catch destroying new_exception_header. |
| new_exception_header->handlerCount = -new_exception_header->handlerCount; |
| globals->uncaughtExceptions += 1; |
| // Call __cxa_end_catch for new_exception_header |
| __cxa_end_catch(); |
| // Call __cxa_end_catch for old_exception_header |
| __cxa_end_catch(); |
| // Renter this catch clause with new_exception_header |
| __cxa_begin_catch(&new_exception_header->unwindHeader); |
| // Rethrow new_exception_header |
| throw; |
| } |
| } |
| // Will a std::bad_exception be catchable by the exception spec at |
| // ttypeIndex? |
| // If no |
| // throw std::bad_exception(); |
| const __shim_type_info* excpType = |
| static_cast<const __shim_type_info*>(&typeid(std::bad_exception)); |
| std::bad_exception be; |
| adjustedPtr = &be; |
| if (!exception_spec_can_catch(ttypeIndex, classInfo, ttypeEncoding, |
| excpType, adjustedPtr, unwind_exception)) |
| { |
| // We need to __cxa_end_catch for both the old exception and the |
| // new exception. Technically we should do it in that order. |
| // But it is expedient to do it in the opposite order: |
| // Call __cxa_end_catch for new_exception_header |
| __cxa_end_catch(); |
| // Throw std::bad_exception will __cxa_end_catch for |
| // old_exception_header |
| throw be; |
| } |
| } |
| } |
| std::__terminate(t_handler); |
| } |
| |
| } // extern "C" |
| |
| } // __cxxabiv1 |
