/*
* Copyright (c) 2008, 2009, 2010, 2011, 2012
* Jonathan Schleifer <js@webkeks.org>
*
* All rights reserved.
*
* This file is part of ObjFW. It may be distributed under the terms of the
* Q Public License 1.0, which can be found in the file LICENSE.QPL included in
* the packaging of this file.
*
* Alternatively, it may be distributed under the terms of the GNU General
* Public License, either version 2 or 3, which can be found in the file
* LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
* file.
*/
#include "config.h"
#include <stdlib.h>
#include <string.h>
#import "runtime.h"
static const uint64_t objc_exception_class = 0x474E55434F424A43; /* GNUCOBJC */
#define _UA_SEARCH_PHASE 0x01
#define _UA_CLEANUP_PHASE 0x02
#define _UA_HANDLER_FRAME 0x04
#define _UA_FORCE_UNWIND 0x08
#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_signed 0x08
#define DW_EH_PE_sleb128 (DW_EH_PE_signed | DW_EH_PE_uleb128)
#define DW_EH_PE_sdata2 (DW_EH_PE_signed | DW_EH_PE_udata2)
#define DW_EH_PE_sdata4 (DW_EH_PE_signed | DW_EH_PE_udata4)
#define DW_EH_PE_sdata8 (DW_EH_PE_signed | DW_EH_PE_udata8)
#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
#define DW_EH_PE_omit 0xFF
#define CLEANUP_FOUND 0x01
#define HANDLER_FOUND 0x02
struct _Unwind_Context;
typedef enum
{
_URC_OK = 0,
_URC_FATAL_PHASE1_ERROR = 3,
_URC_END_OF_STACK = 5,
_URC_HANDLER_FOUND = 6,
_URC_INSTALL_CONTEXT = 7,
_URC_CONTINUE_UNWIND = 8,
_URC_FAILURE = 9
} _Unwind_Reason_Code;
struct objc_exception {
struct _Unwind_Exception {
uint64_t class;
void (*cleanup)(_Unwind_Reason_Code, struct _Unwind_Exception*);
#if defined(__arm__) || defined(__ARM__)
/* From "Exception Handling ABI for the ARM(R) Architecture" */
struct {
uint32_t reserved1, reserved2, reserved3, reserved4;
uint32_t reserved;
} unwinder_cache;
struct {
uint32_t sp;
uint32_t bitpattern[5];
} barrier_cache;
struct {
uint32_t bitpattern[4];
} cleanup_cache;
struct {
uint32_t fnstart;
uint32_t *ehtp;
uint32_t additional;
uint32_t reserved1;
} pr_cache;
long long int : 0;
#else
/*
* The Itanium Exception ABI says to have those and never touch
* them.
*/
uintptr_t private1, private2;
#endif
} exception;
id object;
#if !defined(__arm__) && !defined(__ARM__)
uintptr_t landingpad;
intptr_t filter;
#endif
};
struct lsda {
uintptr_t region_start, landingpads_start;
uint8_t typestable_enc;
const uint8_t *typestable;
uintptr_t typestable_base;
uint8_t callsites_enc;
const uint8_t *callsites, *actiontable;
};
extern _Unwind_Reason_Code _Unwind_RaiseException(struct _Unwind_Exception*);
extern void* _Unwind_GetLanguageSpecificData(struct _Unwind_Context*);
extern uintptr_t _Unwind_GetRegionStart(struct _Unwind_Context*);
extern uintptr_t _Unwind_GetDataRelBase(struct _Unwind_Context*);
extern uintptr_t _Unwind_GetTextRelBase(struct _Unwind_Context*);
#if defined(__arm__) || defined(__ARM__)
extern _Unwind_Reason_Code __gnu_unwind_frame(struct _Unwind_Exception*,
struct _Unwind_Context*);
extern int _Unwind_VRS_Get(struct _Unwind_Context*, int, uint32_t, int, void*);
extern int _Unwind_VRS_Set(struct _Unwind_Context*, int, uint32_t, int, void*);
# define CONTINUE_UNWIND \
{ \
if (__gnu_unwind_frame(ex, ctx) != _URC_OK) \
return _URC_FAILURE; \
\
return _URC_CONTINUE_UNWIND; \
}
static inline uintptr_t
_Unwind_GetGR(struct _Unwind_Context *ctx, int regno)
{
uintptr_t value;
_Unwind_VRS_Get(ctx, 0, regno, 0, &value);
return value;
}
static inline uintptr_t
_Unwind_GetIP(struct _Unwind_Context *ctx)
{
return _Unwind_GetGR(ctx, 15) & ~1;
}
static inline void
_Unwind_SetGR(struct _Unwind_Context *ctx, int regno, uintptr_t value)
{
_Unwind_VRS_Set(ctx, 0, regno, 0, &value);
}
static inline void
_Unwind_SetIP(struct _Unwind_Context *ctx, uintptr_t value)
{
uintptr_t thumb = _Unwind_GetGR(ctx, 15) & 1;
_Unwind_SetGR(ctx, 15, (value | thumb));
}
#else
# define CONTINUE_UNWIND return _URC_CONTINUE_UNWIND
extern uintptr_t _Unwind_GetIP(struct _Unwind_Context*);
extern void _Unwind_SetIP(struct _Unwind_Context*, uintptr_t);
extern void _Unwind_SetGR(struct _Unwind_Context*, int, uintptr_t);
#endif
static objc_uncaught_exception_handler uncaught_exception_handler;
static uint64_t
read_uleb128(const uint8_t **ptr)
{
uint64_t value = 0;
uint8_t shift = 0;
do {
value |= (**ptr & 0x7F) << shift;
(*ptr)++;
shift += 7;
} while (*(*ptr - 1) & 0x80);
return value;
}
static int64_t
read_sleb128(const uint8_t **ptr)
{
const uint8_t *oldptr = *ptr;
uint8_t bits;
int64_t value;
value = read_uleb128(ptr);
bits = (*ptr - oldptr) * 7;
if (bits < 64 && value & (1 << (bits - 1)))
value |= -(1 << bits);
return value;
}
static uintptr_t
get_base(struct _Unwind_Context *ctx, uint8_t enc)
{
if (enc == DW_EH_PE_omit)
return 0;
switch (enc & 0x70) {
case DW_EH_PE_absptr:
case DW_EH_PE_pcrel:
case DW_EH_PE_aligned:
return 0;
case DW_EH_PE_funcrel:
return _Unwind_GetRegionStart(ctx);
case DW_EH_PE_datarel:
return _Unwind_GetDataRelBase(ctx);
case DW_EH_PE_textrel:
return _Unwind_GetTextRelBase(ctx);
}
abort();
}
static size_t
size_for_encoding(uint8_t enc)
{
if (enc == DW_EH_PE_omit)
return 0;
switch (enc & 0x07) {
case DW_EH_PE_absptr:
return sizeof(void*);
case DW_EH_PE_udata2:
return 2;
case DW_EH_PE_udata4:
return 4;
case DW_EH_PE_udata8:
return 8;
}
abort();
}
static uint64_t
read_value(uint8_t enc, const uint8_t **ptr)
{
uint64_t value;
if (enc == DW_EH_PE_aligned)
/* Not implemented */
abort();
#define READ_TYPE(type) \
{ \
value = *(type*)(void*)*ptr; \
*ptr += size_for_encoding(enc); \
break; \
}
switch (enc & 0x0F) {
case DW_EH_PE_absptr:
READ_TYPE(uintptr_t)
case DW_EH_PE_uleb128:
value = read_uleb128(ptr);
break;
case DW_EH_PE_udata2:
READ_TYPE(uint16_t)
case DW_EH_PE_udata4:
READ_TYPE(uint32_t)
case DW_EH_PE_udata8:
READ_TYPE(uint64_t)
case DW_EH_PE_sleb128:
value = read_sleb128(ptr);
break;
case DW_EH_PE_sdata2:
READ_TYPE(int16_t)
case DW_EH_PE_sdata4:
READ_TYPE(int32_t)
case DW_EH_PE_sdata8:
READ_TYPE(int64_t)
default:
abort();
}
#undef READ_TYPE
return value;
}
#if !defined(__arm__) && !defined(__ARM__)
static uint64_t
resolve_value(uint64_t value, uint8_t enc, const uint8_t *start, uint64_t base)
{
if (value == 0)
return 0;
value += ((enc & 0x70) == DW_EH_PE_pcrel ? (uintptr_t)start : base);
if (enc & DW_EH_PE_indirect)
value = *(uint64_t*)(uintptr_t)value;
return value;
}
#endif
static void
read_lsda(struct _Unwind_Context *ctx, const uint8_t *ptr, struct lsda *lsda)
{
uint8_t landingpads_start_enc;
uintptr_t callsites_size;
lsda->region_start = _Unwind_GetRegionStart(ctx);
lsda->landingpads_start = lsda->region_start;
lsda->typestable = NULL;
if ((landingpads_start_enc = *ptr++) != DW_EH_PE_omit)
lsda->landingpads_start =
(uintptr_t)read_value(landingpads_start_enc, &ptr);
if ((lsda->typestable_enc = *ptr++) != DW_EH_PE_omit) {
uintptr_t tmp = (uintptr_t)read_uleb128(&ptr);
lsda->typestable = ptr + tmp;
}
lsda->typestable_base = get_base(ctx, lsda->typestable_enc);
lsda->callsites_enc = *ptr++;
callsites_size = (uintptr_t)read_uleb128(&ptr);
lsda->callsites = ptr;
lsda->actiontable = lsda->callsites + callsites_size;
}
static BOOL
find_callsite(struct _Unwind_Context *ctx, struct lsda *lsda,
uintptr_t *landingpad, const uint8_t **actionrecords)
{
uintptr_t ip = _Unwind_GetIP(ctx);
const uint8_t *ptr;
*landingpad = 0;
*actionrecords = NULL;
ptr = lsda->callsites;
while (ptr < lsda->actiontable) {
uintptr_t callsite_start, callsite_len, callsite_landingpad;
uintptr_t callsite_action;
callsite_start = lsda->region_start +
(uintptr_t)read_value(lsda->callsites_enc, &ptr);
callsite_len = (uintptr_t)read_value(lsda->callsites_enc, &ptr);
callsite_landingpad =
(uintptr_t)read_value(lsda->callsites_enc, &ptr);
callsite_action = (uintptr_t)read_uleb128(&ptr);
/* We can stop if we passed IP, as the table is sorted */
if (callsite_start >= ip)
break;
if (callsite_start + callsite_len >= ip) {
if (callsite_landingpad != 0)
*landingpad = lsda->landingpads_start +
callsite_landingpad;
if (callsite_action != 0)
*actionrecords = lsda->actiontable +
callsite_action - 1;
return YES;
}
}
return NO;
}
static BOOL
class_matches(Class class, id object)
{
Class iter;
if (class == Nil)
return YES;
if (object == nil)
return NO;
for (iter = object_getClass(object); iter != Nil;
iter = class_getSuperclass(iter))
if (iter == class)
return YES;
return NO;
}
static uint8_t
find_actionrecord(const uint8_t *actionrecords, struct lsda *lsda, int actions,
BOOL foreign, struct objc_exception *e, intptr_t *filtervalue)
{
uint8_t found = 0;
const uint8_t *ptr;
intptr_t filter, displacement;
do {
ptr = actionrecords;
filter = (intptr_t)read_sleb128(&ptr);
/*
* Get the next action record. Since read_sleb128 modifies ptr,
* we first set the actionrecord to the current ptr and then
* add the displacement.
*/
actionrecords = ptr;
displacement = (intptr_t)read_sleb128(&ptr);
actionrecords += displacement;
if (filter > 0 && !(actions & _UA_FORCE_UNWIND) && !foreign) {
Class class;
uintptr_t c;
const uint8_t *tmp;
#if defined(__arm__) || defined(__ARM__)
tmp = lsda->typestable - (filter * 4);
c = *(uintptr_t*)tmp;
if (c != 0) {
c += (uintptr_t)tmp;
c = *(uintptr_t*)c;
}
#else
uintptr_t i;
i = filter * size_for_encoding(lsda->typestable_enc);
tmp = lsda->typestable - i;
c = (uintptr_t)read_value(lsda->typestable_enc, &tmp);
c = (uintptr_t)resolve_value(c, lsda->typestable_enc,
lsda->typestable - i, lsda->typestable_base);
#endif
class = (c != 0 ? objc_get_class((const char*)c) : Nil);
if (class_matches(class, e->object)) {
*filtervalue = filter;
return (found | HANDLER_FOUND);
}
} else if (filter == 0)
found |= CLEANUP_FOUND;
else
abort();
} while (displacement != 0);
return found;
}
#if defined(__arm__) || defined(__ARM__)
_Unwind_Reason_Code
__gnu_objc_personality_v0(uint32_t state, struct _Unwind_Exception *ex,
struct _Unwind_Context *ctx)
{
int version = 1;
uint64_t ex_class = ex->class;
int actions;
switch (state) {
case 0: /* _US_VIRTUAL_UNWIND_FRAME */
actions = _UA_SEARCH_PHASE;
break;
case 1: /* _US_UNWIND_FRAME_STARTING */
actions = _UA_CLEANUP_PHASE;
if ((ex->barrier_cache.sp == _Unwind_GetGR(ctx, 13)) != 0)
actions |= _UA_HANDLER_FRAME;
break;
case 2: /* _US_UNWIND_FRAME_RESUME */
CONTINUE_UNWIND;
default:
return _URC_FAILURE;
}
_Unwind_SetGR(ctx, 12, (uintptr_t)ex);
#else
_Unwind_Reason_Code
__gnu_objc_personality_v0(int version, int actions, uint64_t ex_class,
struct _Unwind_Exception *ex, struct _Unwind_Context *ctx)
{
#endif
struct objc_exception *e = (struct objc_exception*)ex;
BOOL foreign = (ex_class != objc_exception_class);
const uint8_t *lsda_addr, *actionrecords;
struct lsda lsda;
uintptr_t landingpad = 0;
uint8_t found = 0;
intptr_t filter = 0;
if (version != 1)
return _URC_FATAL_PHASE1_ERROR;
if (ctx == NULL)
abort();
/*
* We already cached everything we found in phase 1, so we only need
* to install the context in phase 2.
*/
if (actions & _UA_HANDLER_FRAME && !foreign) {
/*
* For handlers, reg #0 must be the exception's object and reg
* #1 the filter.
*/
_Unwind_SetGR(ctx, __builtin_eh_return_data_regno(0),
(uintptr_t)e->object);
#if defined(__arm__) || defined(__ARM__)
_Unwind_SetGR(ctx, __builtin_eh_return_data_regno(1),
ex->barrier_cache.bitpattern[1]);
_Unwind_SetIP(ctx, ex->barrier_cache.bitpattern[3]);
#else
_Unwind_SetGR(ctx, __builtin_eh_return_data_regno(1),
e->filter);
_Unwind_SetIP(ctx, e->landingpad);
#endif
free(ex);
return _URC_INSTALL_CONTEXT;
}
/* No LSDA -> nothing to handle */
if ((lsda_addr = _Unwind_GetLanguageSpecificData(ctx)) == NULL)
CONTINUE_UNWIND;
read_lsda(ctx, lsda_addr, &lsda);
if (!find_callsite(ctx, &lsda, &landingpad, &actionrecords))
CONTINUE_UNWIND;
if (landingpad != 0 && actionrecords == NULL)
found = CLEANUP_FOUND;
else if (landingpad != 0)
found = find_actionrecord(actionrecords, &lsda, actions,
foreign, e, &filter);
if (!found)
CONTINUE_UNWIND;
if (actions & _UA_SEARCH_PHASE) {
if (!(found & HANDLER_FOUND))
CONTINUE_UNWIND;
/* Cache it so we don't have to search it again in phase 2 */
if (!foreign) {
#if defined(__arm__) || defined(__ARM__)
ex->barrier_cache.sp = _Unwind_GetGR(ctx, 13);
ex->barrier_cache.bitpattern[1] = filter;
ex->barrier_cache.bitpattern[3] = landingpad;
#else
e->landingpad = landingpad;
e->filter = filter;
#endif
}
return _URC_HANDLER_FOUND;
} else if (actions & _UA_CLEANUP_PHASE) {
/* For cleanup, reg #0 must be the exception and reg #1 zero */
_Unwind_SetGR(ctx, __builtin_eh_return_data_regno(0),
(uintptr_t)e);
_Unwind_SetGR(ctx, __builtin_eh_return_data_regno(1), 0);
_Unwind_SetIP(ctx, landingpad);
return _URC_INSTALL_CONTEXT;
}
abort();
}
static void
cleanup(_Unwind_Reason_Code reason, struct _Unwind_Exception *ex)
{
free(ex);
}
void
objc_exception_throw(id object)
{
struct objc_exception *e;
if ((e = malloc(sizeof(*e))) == NULL)
abort();
memset(e, 0, sizeof(*e));
e->exception.class = objc_exception_class;
e->exception.cleanup = cleanup;
e->object = object;
if (_Unwind_RaiseException(&e->exception) == _URC_END_OF_STACK &&
uncaught_exception_handler != NULL)
uncaught_exception_handler(object);
abort();
}
objc_uncaught_exception_handler
objc_setUncaughtExceptionHandler(objc_uncaught_exception_handler handler)
{
objc_uncaught_exception_handler old = uncaught_exception_handler;
uncaught_exception_handler = handler;
return old;
}