source: libcfa/src/exception.c @ 13600e8

Last change on this file since 13600e8 was 13600e8, checked in by Peter A. Buhr <pabuhr@…>, 8 months ago

fix error when exception propagation does not find a handler and print appropriate message

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File size: 21.7 KB
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1//
2// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
3//
4// The contents of this file are covered under the licence agreement in the
5// file "LICENCE" distributed with Cforall.
6//
7// exception.c --
8//
9// Author           : Andrew Beach
10// Created On       : Mon Jun 26 15:13:00 2017
11// Last Modified By : Peter A. Buhr
12// Last Modified On : Thu Aug 10 16:45:22 2023
13// Update Count     : 69
14//
15
16// Normally we would get this from the CFA prelude.
17#include <stddef.h> // for size_t
18
19#include <unwind.h> // for struct _Unwind_Exception {...};
20
21#include "exception.h"
22
23#include <stdlib.h>
24#include <stdio.h>
25#include <bits/debug.hfa>
26#include "concurrency/invoke.h"
27#include "stdhdr/assert.h"
28#include "virtual.h"
29
30extern void __cabi_abort( const char fmt[], ... );
31
32#pragma GCC visibility push(default)
33
34#include "lsda.h"
35
36/* The exception class for our exceptions. Because of the vendor component
37 * its value would not be standard.
38 * Vendor: UWPL
39 * Language: CFA\0
40 */
41const _Unwind_Exception_Class __cfaehm_exception_class = 0x4c50575500414643;
42
43// Base Exception type id:
44struct __cfavir_type_info __cfatid_exception_t = {
45        NULL,
46};
47
48
49// Get the current exception context.
50// There can be a single global until multithreading occurs, then each stack
51// needs its own. We get this from libcfathreads (no weak attribute).
52__attribute__((weak)) struct exception_context_t * this_exception_context() {
53        static struct exception_context_t shared_stack = {NULL, NULL};
54        return &shared_stack;
55}
56
57
58// RESUMPTION ================================================================
59
60static void reset_top_resume(struct __cfaehm_try_resume_node ** store) {
61        this_exception_context()->top_resume = *store;
62}
63
64void __cfaehm_throw_resume(exception_t * except, void (*defaultHandler)(exception_t *)) {
65        struct exception_context_t * context = this_exception_context();
66
67        __cfadbg_print_safe(exception, "Throwing resumption exception\n");
68
69        {
70                __attribute__((cleanup(reset_top_resume)))
71                struct __cfaehm_try_resume_node * original_head = context->top_resume;
72                struct __cfaehm_try_resume_node * current = context->top_resume;
73
74                for ( ; current ; current = current->next) {
75                        context->top_resume = current->next;
76                        if (current->handler(except)) {
77                                return;
78                        }
79                }
80        } // End the search and return to the top of the stack.
81
82        // No handler found, fall back to the default operation.
83        __cfadbg_print_safe(exception, "Unhandled exception\n");
84        defaultHandler(except);
85}
86
87// Do we control where exceptions get thrown even with concurency?
88// If not these are not quite thread safe, the cleanup hook has to
89// be added after the node is built but before it is made the top node.
90
91void __cfaehm_try_resume_setup(struct __cfaehm_try_resume_node * node,
92                        _Bool (*handler)(exception_t * except)) {
93        struct exception_context_t * context = this_exception_context();
94        node->next = context->top_resume;
95        node->handler = handler;
96        context->top_resume = node;
97}
98
99void __cfaehm_try_resume_cleanup(struct __cfaehm_try_resume_node * node) {
100        struct exception_context_t * context = this_exception_context();
101        context->top_resume = node->next;
102}
103
104
105// MEMORY MANAGEMENT =========================================================
106
107#define NODE_TO_EXCEPT(node) ((exception_t *)(1 + (node)))
108#define EXCEPT_TO_NODE(except) ((struct __cfaehm_node *)(except) - 1)
109#define UNWIND_TO_NODE(unwind) ((struct __cfaehm_node *)(unwind))
110#define NULL_MAP(map, ptr) ((ptr) ? (map(ptr)) : NULL)
111
112// How to clean up an exception in various situations.
113static void __cfaehm_exception_cleanup(
114                _Unwind_Reason_Code reason,
115                struct _Unwind_Exception * exception) {
116        switch (reason) {
117        case _URC_FOREIGN_EXCEPTION_CAUGHT:
118                // This one we could clean-up to allow cross-language exceptions.
119        case _URC_FATAL_PHASE1_ERROR:
120        case _URC_FATAL_PHASE2_ERROR:
121        default:
122                abort();
123        }
124}
125
126// Creates a copy of the indicated exception and sets current_exception to it.
127void __cfaehm_allocate_exception( exception_t * except ) {
128        struct exception_context_t * context = this_exception_context();
129
130        // Allocate memory for the exception.
131        struct __cfaehm_node * store = malloc(
132                sizeof( struct __cfaehm_node ) + except->virtual_table->size );
133
134        if ( ! store ) {
135                // Failure: cannot allocate exception. Terminate thread.
136                abort(); // <- Although I think it might be the process.
137        }
138
139        // Initialize the node:
140        exception_t * except_store = NODE_TO_EXCEPT(store);
141        store->unwind_exception.exception_class = __cfaehm_exception_class;
142        store->unwind_exception.exception_cleanup = __cfaehm_exception_cleanup;
143        store->handler_index = 0;
144        except->virtual_table->copy( except_store, except );
145
146        // Add the node to the list:
147        store->next = NULL_MAP(EXCEPT_TO_NODE, context->current_exception);
148        context->current_exception = except_store;
149}
150
151// Delete the provided exception, unsetting current_exception if relivant.
152static void __cfaehm_delete_exception( exception_t * except ) {
153        struct exception_context_t * context = this_exception_context();
154
155        __cfadbg_print_safe(exception, "Deleting Exception\n");
156
157        // Remove the exception from the list.
158        struct __cfaehm_node * to_free = EXCEPT_TO_NODE(except);
159        struct __cfaehm_node * node;
160
161        if ( context->current_exception == except ) {
162                node = to_free->next;
163                context->current_exception = NULL_MAP(NODE_TO_EXCEPT, node);
164        } else {
165                node = EXCEPT_TO_NODE(context->current_exception);
166                // It may always be in the first or second position.
167                while ( to_free != node->next ) {
168                        node = node->next;
169                }
170                node->next = to_free->next;
171        }
172
173        // Free the old exception node.
174        except->virtual_table->free( except );
175        free( to_free );
176}
177
178// CANCELLATION ==============================================================
179
180// Function needed by force unwind
181// It basically says to unwind the whole stack and then exit when we reach the end of the stack
182static _Unwind_Reason_Code _Stop_Fn(
183                int version,
184                _Unwind_Action actions,
185                _Unwind_Exception_Class exception_class,
186                struct _Unwind_Exception * unwind_exception,
187                struct _Unwind_Context * unwind_context,
188                void * stop_param) {
189        // Verify actions follow the rules we expect.
190        verify(actions & _UA_CLEANUP_PHASE);
191        verify(actions & _UA_FORCE_UNWIND);
192        verify(!(actions & _UA_SEARCH_PHASE));
193        verify(!(actions & _UA_HANDLER_FRAME));
194
195        if ( actions & _UA_END_OF_STACK ) {
196                __cabi_abort(
197                        "Propagation failed to find a matching handler.\n"
198                        "Possible cause is a missing try block with appropriate catch clause for specified exception type.\n"
199                        "Last exception name or message: %s.\n",
200                        NODE_TO_EXCEPT( UNWIND_TO_NODE( unwind_exception ) )->
201                                virtual_table->msg( NODE_TO_EXCEPT( UNWIND_TO_NODE( unwind_exception ) ) )
202                );
203        } else {
204                return _URC_NO_REASON;
205        }
206}
207
208__attribute__((weak)) _Unwind_Reason_Code
209__cfaehm_cancellation_unwind( struct _Unwind_Exception * exception ) {
210        return _Unwind_ForcedUnwind( exception, _Stop_Fn, (void*)0x22 );
211}
212
213// Cancel the current stack, prefroming approprate clean-up and messaging.
214void __cfaehm_cancel_stack( exception_t * exception ) {
215        __cfaehm_allocate_exception( exception );
216
217        struct exception_context_t * context = this_exception_context();
218        struct __cfaehm_node * node = EXCEPT_TO_NODE(context->current_exception);
219
220        _Unwind_Reason_Code ret;
221        ret = __cfaehm_cancellation_unwind( &node->unwind_exception );
222        printf("UNWIND ERROR %d after force unwind\n", ret);
223        abort();
224}
225
226
227// TERMINATION ===============================================================
228
229// If this isn't a rethrow (*except==0), delete the provided exception.
230void __cfaehm_cleanup_terminate( void * except ) {
231        if ( *(void**)except ) __cfaehm_delete_exception( *(exception_t **)except );
232}
233
234static void __cfaehm_cleanup_default( exception_t ** except ) {
235        __cfaehm_delete_exception( *except );
236        *except = NULL;
237}
238
239// The exception that is being thrown must already be stored.
240void __cfaehm_begin_unwind(void(*defaultHandler)(exception_t *)) {
241        struct exception_context_t * context = this_exception_context();
242        if ( NULL == context->current_exception ) {
243                printf("UNWIND ERROR missing exception in begin unwind\n");
244                abort();
245        }
246        struct _Unwind_Exception * storage =
247                &EXCEPT_TO_NODE(context->current_exception)->unwind_exception;
248
249        // Call stdlibc to raise the exception
250        __cfadbg_print_safe(exception, "Begin unwinding (storage &p, context %p)\n", storage, context);
251        _Unwind_Reason_Code ret = _Unwind_RaiseException( storage );
252
253        // If we reach here it means something happened. For resumption to work we need to find a way
254        // to return back to here. Most of them will probably boil down to setting a global flag and
255        // making the phase 1 either stop or fail. Causing an error on purpose may help avoiding
256        // unnecessary work but it might have some weird side effects. If we just pretend no handler
257        // was found that would work but may be expensive for no reason since we will always search
258        // the whole stack.
259
260#if defined( __x86_64 ) || defined( __i386 )
261        // We did not simply reach the end of the stack without finding a handler. This is an error.
262        if ( ret != _URC_END_OF_STACK ) {
263#else // defined( __ARM_ARCH )
264        // The return code from _Unwind_RaiseException seems to be corrupt on ARM at end of stack.
265        // This workaround tries to keep default exception handling working.
266        if ( ret == _URC_FATAL_PHASE1_ERROR || ret == _URC_FATAL_PHASE2_ERROR ) {
267#endif
268                printf("UNWIND ERROR %d after raise exception\n", ret);
269                abort();
270        }
271
272        // No handler found, go to the default operation.
273        __cfadbg_print_safe(exception, "Uncaught exception %p\n", storage);
274
275        __attribute__((cleanup(__cfaehm_cleanup_default)))
276        exception_t * exception = context->current_exception;
277        defaultHandler( exception );
278}
279
280void __cfaehm_throw_terminate( exception_t * val, void (*defaultHandler)(exception_t *) ) {
281        __cfadbg_print_safe(exception, "Throwing termination exception\n");
282
283        __cfaehm_allocate_exception( val );
284        __cfaehm_begin_unwind( defaultHandler );
285}
286
287static __attribute__((noreturn)) void __cfaehm_rethrow_adapter( exception_t * except ) {
288        // TODO: Print some error message.
289        (void)except;
290        abort();
291}
292
293void __cfaehm_rethrow_terminate(void) {
294        __cfadbg_print_safe(exception, "Rethrowing termination exception\n");
295
296        __cfaehm_begin_unwind( __cfaehm_rethrow_adapter );
297        abort();
298}
299
300#if defined( __x86_64 ) || defined( __i386 ) || defined( __ARM_ARCH )
301// This is our personality routine. For every stack frame annotated with
302// ".cfi_personality 0x3,__gcfa_personality_v0" this function will be called twice when unwinding.
303//  Once in the search phase and once in the cleanup phase.
304_Unwind_Reason_Code __gcfa_personality_v0(
305                int version,
306                _Unwind_Action actions,
307                unsigned long long exception_class,
308                struct _Unwind_Exception * unwind_exception,
309                struct _Unwind_Context * unwind_context)
310{
311
312        //__cfadbg_print_safe(exception, "CFA: 0x%lx\n", _Unwind_GetCFA(context));
313        __cfadbg_print_safe(exception, "Personality function (%d, %x, %llu, %p, %p):",
314                        version, actions, exception_class, unwind_exception, unwind_context);
315
316        // Verify that actions follow the rules we expect.
317        // This function should never be called at the end of the stack.
318        verify(!(actions & _UA_END_OF_STACK));
319        // Either only the search phase flag is set or...
320        if (actions & _UA_SEARCH_PHASE) {
321                verify(actions == _UA_SEARCH_PHASE);
322                __cfadbg_print_safe(exception, " lookup phase");
323        // ... we are in clean-up phase.
324        } else {
325                verify(actions & _UA_CLEANUP_PHASE);
326                __cfadbg_print_safe(exception, " cleanup phase");
327                // We shouldn't be the handler frame during forced unwind.
328                if (actions & _UA_HANDLER_FRAME) {
329                        verify(!(actions & _UA_FORCE_UNWIND));
330                        __cfadbg_print_safe(exception, " (handler frame)");
331                } else if (actions & _UA_FORCE_UNWIND) {
332                        __cfadbg_print_safe(exception, " (force unwind)");
333                }
334        }
335
336        // Get a pointer to the language specific data from which we will read what we need
337        const unsigned char * lsd = _Unwind_GetLanguageSpecificData( unwind_context );
338
339        if ( !lsd ) {   //Nothing to do, keep unwinding
340                printf(" no LSD");
341                goto UNWIND;
342        }
343
344        // Get the instuction pointer and a reading pointer into the exception table
345        lsda_header_info lsd_info;
346        const unsigned char * cur_ptr = parse_lsda_header(unwind_context, lsd, &lsd_info);
347        _Unwind_Ptr instruction_ptr = _Unwind_GetIP(unwind_context);
348
349        struct exception_context_t * context = this_exception_context();
350
351        // Linearly search the table for stuff to do
352        while ( cur_ptr < lsd_info.action_table ) {
353                _Unwind_Ptr callsite_start;
354                _Unwind_Ptr callsite_len;
355                _Unwind_Ptr callsite_landing_pad;
356                _uleb128_t  callsite_action;
357
358                // Decode the common stuff we have in here
359                cur_ptr = read_encoded_value(0, lsd_info.call_site_encoding, cur_ptr, &callsite_start);
360                cur_ptr = read_encoded_value(0, lsd_info.call_site_encoding, cur_ptr, &callsite_len);
361                cur_ptr = read_encoded_value(0, lsd_info.call_site_encoding, cur_ptr, &callsite_landing_pad);
362                cur_ptr = read_uleb128(cur_ptr, &callsite_action);
363
364                // Have we reach the correct frame info yet?
365                if ( lsd_info.Start + callsite_start + callsite_len < instruction_ptr ) {
366#ifdef __CFA_DEBUG_PRINT__
367                        void * ls = (void*)lsd_info.Start;
368                        void * cs = (void*)callsite_start;
369                        void * cl = (void*)callsite_len;
370                        void * bp = (void*)lsd_info.Start + callsite_start;
371                        void * ep = (void*)lsd_info.Start + callsite_start + callsite_len;
372                        void * ip = (void*)instruction_ptr;
373                        __cfadbg_print_safe(exception, "\nfound %p - %p (%p, %p, %p), looking for %p\n",
374                                        bp, ep, ls, cs, cl, ip);
375#endif // __CFA_DEBUG_PRINT__
376                        continue;
377                }
378
379                // Have we gone too far?
380                if ( lsd_info.Start + callsite_start > instruction_ptr ) {
381                        printf(" gone too far");
382                        break;
383                }
384
385                // Check for what we must do:
386                if ( 0 == callsite_landing_pad ) {
387                        // Nothing to do, move along
388                        __cfadbg_print_safe(exception, " no landing pad");
389                } else if (actions & _UA_SEARCH_PHASE) {
390                        // In search phase, these means we found a potential handler we must check.
391
392                        // We have arbitrarily decided that 0 means nothing to do and 1 means there is
393                        // a potential handler. This doesn't seem to conflict the gcc default behavior.
394                        if (callsite_action != 0) {
395                                // Now we want to run some code to see if the handler matches
396                                // This is the tricky part where we want to the power to run arbitrary code
397                                // However, generating a new exception table entry and try routine every time
398                                // is way more expansive than we might like
399                                // The information we have is :
400                                //  - The GR (Series of registers)
401                                //    GR1=GP Global Pointer of frame ref by context
402                                //  - The instruction pointer
403                                //  - The instruction pointer info (???)
404                                //  - The CFA (Canonical Frame Address)
405                                //  - The BSP (Probably the base stack pointer)
406
407                                // The current apprach uses one exception table entry per try block
408                                _uleb128_t imatcher;
409                                // Get the relative offset to the {...}?
410                                cur_ptr = read_uleb128(cur_ptr, &imatcher);
411
412                                _Unwind_Word match_pos =
413#                               if defined( __x86_64 )
414                                    _Unwind_GetCFA(unwind_context) + 8;
415#                               elif defined( __i386 )
416                                    _Unwind_GetCFA(unwind_context) + 24;
417#                               elif defined( __ARM_ARCH )
418                                    _Unwind_GetCFA(unwind_context) + 40;
419#                               endif
420                                int (*matcher)(exception_t *) = *(int(**)(exception_t *))match_pos;
421
422                                int index = matcher(context->current_exception);
423                                _Unwind_Reason_Code ret = (0 == index)
424                                        ? _URC_CONTINUE_UNWIND : _URC_HANDLER_FOUND;
425                                UNWIND_TO_NODE(unwind_exception)->handler_index = index;
426
427                                // Based on the return value, check if we matched the exception
428                                if (ret == _URC_HANDLER_FOUND) {
429                                        __cfadbg_print_safe(exception, " handler found\n");
430                                } else {
431                                        // TODO: Continue the search if there is more in the table.
432                                        __cfadbg_print_safe(exception, " no handler\n");
433                                }
434                                return ret;
435                        }
436
437                        // This is only a cleanup handler, ignore it
438                        __cfadbg_print_safe(exception, " no action");
439                } else {
440                        // In clean-up phase, no destructors here but this could be the handler.
441
442                        if ( (callsite_action != 0) && !(actions & _UA_HANDLER_FRAME) ){
443                                // If this is a potential exception handler
444                                // but not the one that matched the exception in the seach phase,
445                                // just ignore it
446                                goto UNWIND;
447                        }
448
449                        // We need to run some clean-up or a handler
450                        // These statment do the right thing but I don't know any specifics at all
451                        _Unwind_SetGR( unwind_context, __builtin_eh_return_data_regno(0),
452                                (_Unwind_Ptr)unwind_exception );
453                        _Unwind_SetGR( unwind_context, __builtin_eh_return_data_regno(1), 0 );
454
455                        // I assume this sets the instruction pointer to the adress of the landing pad
456                        // It doesn't actually set it, it only state the value that needs to be set once we
457                        // return _URC_INSTALL_CONTEXT
458                        _Unwind_SetIP( unwind_context, ((lsd_info.LPStart) + (callsite_landing_pad)) );
459
460                        __cfadbg_print_safe(exception, " action\n");
461
462                        // Return have some action to run
463                        return _URC_INSTALL_CONTEXT;
464                }
465        }
466        // No handling found
467        __cfadbg_print_safe(exception, " table end reached");
468
469        UNWIND:
470        __cfadbg_print_safe(exception, " unwind\n");
471
472        // Keep unwinding the stack
473        return _URC_CONTINUE_UNWIND;
474}
475
476#pragma GCC push_options
477#pragma GCC optimize(0)
478
479// Try statements are hoisted out see comments for details. While this could probably be unique
480// and simply linked from libcfa but there is one problem left, see the exception table for details
481__attribute__((noinline))
482void __cfaehm_try_terminate(void (*try_block)(),
483                void (*catch_block)(int index, exception_t * except),
484                __attribute__((unused)) int (*match_block)(exception_t * except)) {
485        //! volatile int xy = 0;
486        //! printf("%p %p %p %p\n", &try_block, &catch_block, &match_block, &xy);
487
488        // Setup the personality routine and exception table.
489        // Unforturnately these clobber gcc cancellation support which means we can't get access to
490        // the attribute cleanup tables at the same time. We would have to inspect the assembly to
491        // create a new set ourselves.
492#ifdef __PIC__
493        asm volatile (".cfi_personality 0x9b,CFA.ref.__gcfa_personality_v0");
494        asm volatile (".cfi_lsda 0x1b, .LLSDACFA2");
495#else
496        asm volatile (".cfi_personality 0x3,__gcfa_personality_v0");
497        asm volatile (".cfi_lsda 0x3, .LLSDACFA2");
498#endif
499
500        // Label which defines the start of the area for which the handler is setup.
501        asm volatile (".TRYSTART:");
502
503        // The actual statements of the try blocks
504        try_block();
505
506        // asm statement to prevent deadcode removal
507        asm volatile goto ("" : : : : CATCH );
508
509        // Normal return for when there is no throw.
510        return;
511
512        // Exceptionnal path
513        CATCH : __attribute__(( unused ));
514        // Label which defines the end of the area for which the handler is setup.
515        asm volatile (".TRYEND:");
516        // Label which defines the start of the exception landing pad. Basically what is called when
517        // the exception is caught. Note, if multiple handlers are given, the multiplexing should be
518        // done by the generated code, not the exception runtime.
519        asm volatile (".CATCH:");
520
521        // Exception handler
522        // Note: Saving the exception context on the stack breaks termination exceptions.
523        catch_block( EXCEPT_TO_NODE( this_exception_context()->current_exception )->handler_index,
524                     this_exception_context()->current_exception );
525}
526
527// Exception table data we need to generate. While this is almost generic, the custom data refers
528// to {*}try_terminate, which is no way generic. Some more works need to be done if we want to
529// have a single call to the try routine.
530
531#ifdef __PIC__
532asm (
533        // HEADER
534        ".LFECFA1:\n"
535#if defined( __x86_64 ) || defined( __i386 )
536        "       .globl  __gcfa_personality_v0\n"
537#else // defined( __ARM_ARCH )
538        "       .global __gcfa_personality_v0\n"
539#endif
540        "       .section        .gcc_except_table,\"a\",@progbits\n"
541        // TABLE HEADER (important field is the BODY length at the end)
542        ".LLSDACFA2:\n"
543        "       .byte   0xff\n"
544        "       .byte   0xff\n"
545        "       .byte   0x1\n"
546        "       .uleb128 .LLSDACSECFA2-.LLSDACSBCFA2\n"
547        // BODY (language specific data)
548        // This uses language specific data and can be modified arbitrarily
549        // We use handled area offset, handled area length,
550        // handler landing pad offset and 1 (action code, gcc seems to use 0).
551        ".LLSDACSBCFA2:\n"
552        "       .uleb128 .TRYSTART-__cfaehm_try_terminate\n"
553        "       .uleb128 .TRYEND-.TRYSTART\n"
554        "       .uleb128 .CATCH-__cfaehm_try_terminate\n"
555        "       .uleb128 1\n"
556        ".LLSDACSECFA2:\n"
557        // TABLE FOOTER
558        "       .text\n"
559        "       .size   __cfaehm_try_terminate, .-__cfaehm_try_terminate\n"
560);
561
562// Somehow this piece of helps with the resolution of debug symbols.
563__attribute__((unused)) static const int dummy = 0;
564
565asm (
566        // Add a hidden symbol which points at the function.
567        "       .hidden CFA.ref.__gcfa_personality_v0\n"
568        "       .weak   CFA.ref.__gcfa_personality_v0\n"
569#if defined( __x86_64 ) || defined( __i386 )
570        "       .align 8\n"
571#else // defined( __ARM_ARCH )
572        "       .align 3\n"
573#endif
574        "       .type CFA.ref.__gcfa_personality_v0, @object\n"
575        "       .size CFA.ref.__gcfa_personality_v0, 8\n"
576        "CFA.ref.__gcfa_personality_v0:\n"
577#if defined( __x86_64 )
578        "       .quad __gcfa_personality_v0\n"
579#elif defined( __i386 )
580        "       .long __gcfa_personality_v0\n"
581#else // defined( __ARM_ARCH )
582        "       .xword __gcfa_personality_v0\n"
583#endif
584);
585#else // __PIC__
586asm (
587        // HEADER
588        ".LFECFA1:\n"
589#if defined( __x86_64 ) || defined( __i386 )
590        "       .globl  __gcfa_personality_v0\n"
591#else // defined( __ARM_ARCH )
592        "       .global __gcfa_personality_v0\n"
593#endif
594        "       .section        .gcc_except_table,\"a\",@progbits\n"
595        // TABLE HEADER (important field is the BODY length at the end)
596        ".LLSDACFA2:\n"
597        "       .byte   0xff\n"
598        "       .byte   0xff\n"
599        "       .byte   0x1\n"
600        "       .uleb128 .LLSDACSECFA2-.LLSDACSBCFA2\n"
601        // BODY (language specific data)
602        ".LLSDACSBCFA2:\n"
603        //      Handled area start (relative to start of function)
604        "       .uleb128 .TRYSTART-__cfaehm_try_terminate\n"
605        //      Handled area length
606        "       .uleb128 .TRYEND-.TRYSTART\n"
607        //      Handler landing pad address (relative to start of function)
608        "       .uleb128 .CATCH-__cfaehm_try_terminate\n"
609        //      Action code, gcc seems to always use 0.
610        "       .uleb128 1\n"
611        // TABLE FOOTER
612        ".LLSDACSECFA2:\n"
613        "       .text\n"
614        "       .size   __cfaehm_try_terminate, .-__cfaehm_try_terminate\n"
615        "       .ident  \"GCC: (Ubuntu 6.2.0-3ubuntu11~16.04) 6.2.0 20160901\"\n"
616        "       .section        .note.GNU-stack,\"x\",@progbits\n"
617);
618#endif // __PIC__
619
620#pragma GCC pop_options
621
622#else
623        #error unsupported hardware architecture
624#endif // __x86_64 || __i386 || __ARM_ARCH
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