diff options
Diffstat (limited to 'contrib/compiler-rt/lib/gcc_personality_v0.c')
| -rw-r--r-- | contrib/compiler-rt/lib/gcc_personality_v0.c | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/contrib/compiler-rt/lib/gcc_personality_v0.c b/contrib/compiler-rt/lib/gcc_personality_v0.c new file mode 100644 index 0000000..5940190 --- /dev/null +++ b/contrib/compiler-rt/lib/gcc_personality_v0.c @@ -0,0 +1,251 @@ +/* ===-- gcc_personality_v0.c - Implement __gcc_personality_v0 -------------=== + * + * The LLVM Compiler Infrastructure + * + * This file is distributed under the University of Illinois Open Source + * License. See LICENSE.TXT for details. + * + * ===----------------------------------------------------------------------=== + * + */ + +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> + +#include "int_lib.h" + +/* + * _Unwind_* stuff based on C++ ABI public documentation + * http://refspecs.freestandards.org/abi-eh-1.21.html + */ + +typedef enum { + _URC_NO_REASON = 0, + _URC_FOREIGN_EXCEPTION_CAUGHT = 1, + _URC_FATAL_PHASE2_ERROR = 2, + _URC_FATAL_PHASE1_ERROR = 3, + _URC_NORMAL_STOP = 4, + _URC_END_OF_STACK = 5, + _URC_HANDLER_FOUND = 6, + _URC_INSTALL_CONTEXT = 7, + _URC_CONTINUE_UNWIND = 8 +} _Unwind_Reason_Code; + +typedef enum { + _UA_SEARCH_PHASE = 1, + _UA_CLEANUP_PHASE = 2, + _UA_HANDLER_FRAME = 4, + _UA_FORCE_UNWIND = 8, + _UA_END_OF_STACK = 16 +} _Unwind_Action; + +typedef struct _Unwind_Context* _Unwind_Context_t; + +struct _Unwind_Exception { + uint64_t exception_class; + void (*exception_cleanup)(_Unwind_Reason_Code reason, + struct _Unwind_Exception* exc); + uintptr_t private_1; + uintptr_t private_2; +}; + +extern const uint8_t* _Unwind_GetLanguageSpecificData(_Unwind_Context_t c); +extern void _Unwind_SetGR(_Unwind_Context_t c, int i, uintptr_t n); +extern void _Unwind_SetIP(_Unwind_Context_t, uintptr_t new_value); +extern uintptr_t _Unwind_GetIP(_Unwind_Context_t context); +extern uintptr_t _Unwind_GetRegionStart(_Unwind_Context_t context); + + +/* + * Pointer encodings documented at: + * http://refspecs.freestandards.org/LSB_1.3.0/gLSB/gLSB/ehframehdr.html + */ + +#define DW_EH_PE_omit 0xff /* no data follows */ + +#define DW_EH_PE_absptr 0x00 +#define DW_EH_PE_uleb128 0x01 +#define DW_EH_PE_udata2 0x02 +#define DW_EH_PE_udata4 0x03 +#define DW_EH_PE_udata8 0x04 +#define DW_EH_PE_sleb128 0x09 +#define DW_EH_PE_sdata2 0x0A +#define DW_EH_PE_sdata4 0x0B +#define DW_EH_PE_sdata8 0x0C + +#define DW_EH_PE_pcrel 0x10 +#define DW_EH_PE_textrel 0x20 +#define DW_EH_PE_datarel 0x30 +#define DW_EH_PE_funcrel 0x40 +#define DW_EH_PE_aligned 0x50 +#define DW_EH_PE_indirect 0x80 /* gcc extension */ + + + +/* read a uleb128 encoded value and advance pointer */ +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 |= (byte & 0x7f) << shift; + shift += 7; + } while (byte & 0x80); + *data = p; + return result; +} + +/* read a pointer encoded value and advance pointer */ +static uintptr_t readEncodedPointer(const uint8_t** data, uint8_t encoding) +{ + const uint8_t* p = *data; + uintptr_t result = 0; + + if ( encoding == DW_EH_PE_omit ) + return 0; + + /* first get value */ + switch (encoding & 0x0F) { + case DW_EH_PE_absptr: + result = *((uintptr_t*)p); + p += sizeof(uintptr_t); + break; + case DW_EH_PE_uleb128: + result = readULEB128(&p); + break; + case DW_EH_PE_udata2: + result = *((uint16_t*)p); + p += sizeof(uint16_t); + break; + case DW_EH_PE_udata4: + result = *((uint32_t*)p); + p += sizeof(uint32_t); + break; + case DW_EH_PE_udata8: + result = *((uint64_t*)p); + p += sizeof(uint64_t); + break; + case DW_EH_PE_sdata2: + result = *((int16_t*)p); + p += sizeof(int16_t); + break; + case DW_EH_PE_sdata4: + result = *((int32_t*)p); + p += sizeof(int32_t); + break; + case DW_EH_PE_sdata8: + result = *((int64_t*)p); + p += sizeof(int64_t); + break; + case DW_EH_PE_sleb128: + default: + /* not supported */ + compilerrt_abort(); + break; + } + + /* then add relative offset */ + switch ( encoding & 0x70 ) { + case DW_EH_PE_absptr: + /* do nothing */ + break; + case DW_EH_PE_pcrel: + 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 */ + compilerrt_abort(); + break; + } + + /* then apply indirection */ + if (encoding & DW_EH_PE_indirect) { + result = *((uintptr_t*)result); + } + + *data = p; + return result; +} + + +/* + * The C compiler makes references to __gcc_personality_v0 in + * the dwarf unwind information for translation units that use + * __attribute__((cleanup(xx))) on local variables. + * This personality routine is called by the system unwinder + * on each frame as the stack is unwound during a C++ exception + * throw through a C function compiled with -fexceptions. + */ +#if __arm__ +// the setjump-longjump based exceptions personality routine has a different name +_Unwind_Reason_Code __gcc_personality_sj0(int version, _Unwind_Action actions, + uint64_t exceptionClass, struct _Unwind_Exception* exceptionObject, + _Unwind_Context_t context) +#else +_Unwind_Reason_Code __gcc_personality_v0(int version, _Unwind_Action actions, + uint64_t exceptionClass, struct _Unwind_Exception* exceptionObject, + _Unwind_Context_t context) +#endif +{ + /* Since C does not have catch clauses, there is nothing to do during */ + /* phase 1 (the search phase). */ + if ( actions & _UA_SEARCH_PHASE ) + return _URC_CONTINUE_UNWIND; + + /* There is nothing to do if there is no LSDA for this frame. */ + const uint8_t* lsda = _Unwind_GetLanguageSpecificData(context); + if ( lsda == NULL ) + return _URC_CONTINUE_UNWIND; + + uintptr_t pc = _Unwind_GetIP(context)-1; + uintptr_t funcStart = _Unwind_GetRegionStart(context); + uintptr_t pcOffset = pc - funcStart; + + /* Parse LSDA header. */ + uint8_t lpStartEncoding = *lsda++; + if (lpStartEncoding != DW_EH_PE_omit) { + readEncodedPointer(&lsda, lpStartEncoding); + } + uint8_t ttypeEncoding = *lsda++; + if (ttypeEncoding != DW_EH_PE_omit) { + readULEB128(&lsda); + } + /* Walk call-site table looking for range that includes current PC. */ + uint8_t callSiteEncoding = *lsda++; + uint32_t callSiteTableLength = readULEB128(&lsda); + const uint8_t* callSiteTableStart = lsda; + const uint8_t* callSiteTableEnd = callSiteTableStart + callSiteTableLength; + const uint8_t* p=callSiteTableStart; + while (p < callSiteTableEnd) { + uintptr_t start = readEncodedPointer(&p, callSiteEncoding); + uintptr_t length = readEncodedPointer(&p, callSiteEncoding); + uintptr_t landingPad = readEncodedPointer(&p, callSiteEncoding); + readULEB128(&p); /* action value not used for C code */ + if ( landingPad == 0 ) + continue; /* no landing pad for this entry */ + if ( (start <= pcOffset) && (pcOffset < (start+length)) ) { + /* Found landing pad for the PC. + * Set Instruction Pointer to so we re-enter function + * at landing pad. The landing pad is created by the compiler + * to take two parameters in registers. + */ + _Unwind_SetGR(context, __builtin_eh_return_data_regno(0), + (uintptr_t)exceptionObject); + _Unwind_SetGR(context, __builtin_eh_return_data_regno(1), 0); + _Unwind_SetIP(context, funcStart+landingPad); + return _URC_INSTALL_CONTEXT; + } + } + + /* No landing pad found, continue unwinding. */ + return _URC_CONTINUE_UNWIND; +} + |
