2 * msvcrt C++ exception handling
4 * Copyright 2002 Alexandre Julliard
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 * A good reference is the article "How a C++ compiler implements
22 * exception handling" by Vishal Kochhar, available on
23 * www.thecodeproject.com.
27 #include "wine/port.h"
36 #include "wine/exception.h"
38 #include "wine/debug.h"
40 #include "cppexcept.h"
42 WINE_DEFAULT_DEBUG_CHANNEL(seh);
44 #ifdef __i386__ /* CxxFrameHandler is not supported on non-i386 */
46 DWORD cxx_frame_handler( PEXCEPTION_RECORD rec, cxx_exception_frame* frame,
47 PCONTEXT context, EXCEPTION_REGISTRATION_RECORD** dispatch,
48 cxx_function_descr *descr, EXCEPTION_REGISTRATION_RECORD* nested_frame,
49 int nested_trylevel );
51 /* call a function with a given ebp */
52 inline static void *call_ebp_func( void *func, void *ebp )
55 __asm__ __volatile__ ("pushl %%ebp; movl %2,%%ebp; call *%%eax; popl %%ebp" \
56 : "=a" (ret) : "0" (func), "r" (ebp) : "ecx", "edx", "memory" );
60 /* call a copy constructor */
61 inline static void call_copy_ctor( void *func, void *this, void *src, int has_vbase )
63 TRACE( "calling copy ctor %p object %p src %p\n", func, this, src );
65 /* in that case copy ctor takes an extra bool indicating whether to copy the base class */
66 __asm__ __volatile__("pushl $1; pushl %2; call *%0"
67 : : "r" (func), "c" (this), "r" (src) : "eax", "edx", "memory" );
69 __asm__ __volatile__("pushl %2; call *%0"
70 : : "r" (func), "c" (this), "r" (src) : "eax", "edx", "memory" );
73 /* call the destructor of the exception object */
74 inline static void call_dtor( void *func, void *object )
76 __asm__ __volatile__("call *%0" : : "r" (func), "c" (object) : "eax", "edx", "memory" );
79 /* continue execution to the specified address after exception is caught */
80 inline static void DECLSPEC_NORETURN continue_after_catch( cxx_exception_frame* frame, void *addr )
82 __asm__ __volatile__("movl -4(%0),%%esp; leal 12(%0),%%ebp; jmp *%1"
83 : : "r" (frame), "a" (addr) );
84 for (;;) ; /* unreached */
87 static inline void dump_type( const cxx_type_info *type )
89 TRACE( "flags %x type %p %s offsets %d,%d,%d size %d copy ctor %p\n",
90 type->flags, type->type_info, dbgstr_type_info(type->type_info),
91 type->offsets.this_offset, type->offsets.vbase_descr, type->offsets.vbase_offset,
92 type->size, type->copy_ctor );
95 static void dump_exception_type( const cxx_exception_type *type )
99 TRACE( "flags %x destr %p handler %p type info %p\n",
100 type->flags, type->destructor, type->custom_handler, type->type_info_table );
101 for (i = 0; i < type->type_info_table->count; i++)
104 dump_type( type->type_info_table->info[i] );
108 static void dump_function_descr( const cxx_function_descr *descr, const cxx_exception_type *info )
113 TRACE( "magic %x\n", descr->magic );
114 TRACE( "unwind table: %p %d\n", descr->unwind_table, descr->unwind_count );
115 for (i = 0; i < descr->unwind_count; i++)
117 TRACE( " %d: prev %d func %p\n", i,
118 descr->unwind_table[i].prev, descr->unwind_table[i].handler );
120 TRACE( "try table: %p %d\n", descr->tryblock, descr->tryblock_count );
121 for (i = 0; i < descr->tryblock_count; i++)
123 TRACE( " %d: start %d end %d catchlevel %d catch %p %d\n", i,
124 descr->tryblock[i].start_level, descr->tryblock[i].end_level,
125 descr->tryblock[i].catch_level, descr->tryblock[i].catchblock,
126 descr->tryblock[i].catchblock_count );
127 for (j = 0; j < descr->tryblock[i].catchblock_count; j++)
129 catchblock_info *ptr = &descr->tryblock[i].catchblock[j];
130 TRACE( " %d: flags %x offset %d handler %p type %p %s\n",
131 j, ptr->flags, ptr->offset, ptr->handler,
132 ptr->type_info, dbgstr_type_info( ptr->type_info ) );
137 /* check if the exception type is caught by a given catch block, and return the type that matched */
138 static const cxx_type_info *find_caught_type( cxx_exception_type *exc_type, catchblock_info *catchblock )
142 for (i = 0; i < exc_type->type_info_table->count; i++)
144 const cxx_type_info *type = exc_type->type_info_table->info[i];
146 if (!catchblock->type_info) return type; /* catch(...) matches any type */
147 if (catchblock->type_info != type->type_info)
149 if (strcmp( catchblock->type_info->mangled, type->type_info->mangled )) continue;
151 /* type is the same, now check the flags */
152 if ((exc_type->flags & TYPE_FLAG_CONST) &&
153 !(catchblock->flags & TYPE_FLAG_CONST)) continue;
154 if ((exc_type->flags & TYPE_FLAG_VOLATILE) &&
155 !(catchblock->flags & TYPE_FLAG_VOLATILE)) continue;
156 return type; /* it matched */
162 /* copy the exception object where the catch block wants it */
163 static void copy_exception( void *object, cxx_exception_frame *frame,
164 catchblock_info *catchblock, const cxx_type_info *type )
168 if (!catchblock->type_info || !catchblock->type_info->mangled[0]) return;
169 if (!catchblock->offset) return;
170 dest_ptr = (void **)((char *)&frame->ebp + catchblock->offset);
172 if (catchblock->flags & TYPE_FLAG_REFERENCE)
174 *dest_ptr = get_this_pointer( &type->offsets, object );
176 else if (type->flags & CLASS_IS_SIMPLE_TYPE)
178 memmove( dest_ptr, object, type->size );
179 /* if it is a pointer, adjust it */
180 if (type->size == sizeof(void *)) *dest_ptr = get_this_pointer( &type->offsets, *dest_ptr );
182 else /* copy the object */
185 call_copy_ctor( type->copy_ctor, dest_ptr, get_this_pointer(&type->offsets,object),
186 (type->flags & CLASS_HAS_VIRTUAL_BASE_CLASS) );
188 memmove( dest_ptr, get_this_pointer(&type->offsets,object), type->size );
192 /* unwind the local function up to a given trylevel */
193 static void cxx_local_unwind( cxx_exception_frame* frame, cxx_function_descr *descr, int last_level)
196 int trylevel = frame->trylevel;
198 while (trylevel != last_level)
200 if (trylevel < 0 || trylevel >= descr->unwind_count)
202 ERR( "invalid trylevel %d\n", trylevel );
205 handler = descr->unwind_table[trylevel].handler;
208 TRACE( "calling unwind handler %p trylevel %d last %d ebp %p\n",
209 handler, trylevel, last_level, &frame->ebp );
210 call_ebp_func( handler, &frame->ebp );
212 trylevel = descr->unwind_table[trylevel].prev;
214 frame->trylevel = last_level;
217 /* exception frame for nested exceptions in catch block */
218 struct catch_func_nested_frame
220 EXCEPTION_REGISTRATION_RECORD frame; /* standard exception frame */
221 EXCEPTION_RECORD *prev_rec; /* previous record to restore in thread data */
222 cxx_exception_frame *cxx_frame; /* frame of parent exception */
223 cxx_function_descr *descr; /* descriptor of parent exception */
224 int trylevel; /* current try level */
227 /* handler for exceptions happening while calling a catch function */
228 static DWORD catch_function_nested_handler( EXCEPTION_RECORD *rec, EXCEPTION_REGISTRATION_RECORD *frame,
229 CONTEXT *context, EXCEPTION_REGISTRATION_RECORD **dispatcher )
231 struct catch_func_nested_frame *nested_frame = (struct catch_func_nested_frame *)frame;
233 if (rec->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND))
235 msvcrt_get_thread_data()->exc_record = nested_frame->prev_rec;
236 return ExceptionContinueSearch;
240 TRACE( "got nested exception in catch function\n" );
241 return cxx_frame_handler( rec, nested_frame->cxx_frame, context,
242 NULL, nested_frame->descr, &nested_frame->frame,
243 nested_frame->trylevel );
247 /* find and call the appropriate catch block for an exception */
248 /* returns the address to continue execution to after the catch block was called */
249 inline static void call_catch_block( PEXCEPTION_RECORD rec, cxx_exception_frame *frame,
250 cxx_function_descr *descr, int nested_trylevel,
251 cxx_exception_type *info )
255 void *addr, *prev_frame, *object = (void *)rec->ExceptionInformation[1];
256 struct catch_func_nested_frame nested_frame;
257 int trylevel = frame->trylevel;
258 thread_data_t *thread_data = msvcrt_get_thread_data();
260 for (i = 0; i < descr->tryblock_count; i++)
262 tryblock_info *tryblock = &descr->tryblock[i];
264 if (trylevel < tryblock->start_level) continue;
265 if (trylevel > tryblock->end_level) continue;
267 /* got a try block */
268 for (j = 0; j < tryblock->catchblock_count; j++)
270 catchblock_info *catchblock = &tryblock->catchblock[j];
273 const cxx_type_info *type = find_caught_type( info, catchblock );
276 TRACE( "matched type %p in tryblock %d catchblock %d\n", type, i, j );
278 /* copy the exception to its destination on the stack */
279 copy_exception( object, frame, catchblock, type );
283 /* no CXX_EXCEPTION only proceed with a catch(...) block*/
284 if(catchblock->type_info)
286 TRACE("found catch(...) block\n");
289 /* unwind the stack */
290 RtlUnwind( frame, 0, rec, 0 );
291 cxx_local_unwind( frame, descr, tryblock->start_level );
292 frame->trylevel = tryblock->end_level + 1;
294 /* call the catch block */
295 TRACE( "calling catch block %p addr %p ebp %p\n",
296 catchblock, catchblock->handler, &frame->ebp );
298 /* setup an exception block for nested exceptions */
300 nested_frame.frame.Handler = catch_function_nested_handler;
301 nested_frame.prev_rec = thread_data->exc_record;
302 nested_frame.cxx_frame = frame;
303 nested_frame.descr = descr;
304 nested_frame.trylevel = nested_trylevel + 1;
306 __wine_push_frame( &nested_frame.frame );
307 thread_data->exc_record = rec;
308 addr = call_ebp_func( catchblock->handler, &frame->ebp );
309 thread_data->exc_record = nested_frame.prev_rec;
310 __wine_pop_frame( &nested_frame.frame );
312 if (info && info->destructor) call_dtor( info->destructor, object );
313 TRACE( "done, continuing at %p\n", addr );
314 prev_frame = NtCurrentTeb()->Tib.ExceptionList;
315 __wine_pop_frame( prev_frame );
316 continue_after_catch( frame, addr );
322 /*********************************************************************
325 * Implementation of __CxxFrameHandler.
327 DWORD cxx_frame_handler( PEXCEPTION_RECORD rec, cxx_exception_frame* frame,
328 PCONTEXT context, EXCEPTION_REGISTRATION_RECORD** dispatch,
329 cxx_function_descr *descr, EXCEPTION_REGISTRATION_RECORD* nested_frame,
330 int nested_trylevel )
332 cxx_exception_type *exc_type;
334 if (descr->magic != CXX_FRAME_MAGIC)
336 ERR( "invalid frame magic %x\n", descr->magic );
337 return ExceptionContinueSearch;
339 if (rec->ExceptionFlags & (EH_UNWINDING|EH_EXIT_UNWIND))
341 if (descr->unwind_count && !nested_trylevel) cxx_local_unwind( frame, descr, -1 );
342 return ExceptionContinueSearch;
344 if (!descr->tryblock_count) return ExceptionContinueSearch;
346 if(rec->ExceptionCode == CXX_EXCEPTION)
348 exc_type = (cxx_exception_type *)rec->ExceptionInformation[2];
350 if (rec->ExceptionInformation[0] > CXX_FRAME_MAGIC &&
351 exc_type->custom_handler)
353 return exc_type->custom_handler( rec, frame, context, dispatch,
354 descr, nested_trylevel, nested_frame, 0 );
356 if (!exc_type) /* nested exception, fetch info from original exception */
358 rec = msvcrt_get_thread_data()->exc_record;
359 exc_type = (cxx_exception_type *)rec->ExceptionInformation[2];
363 TRACE("handling C++ exception rec %p frame %p trylevel %d descr %p nested_frame %p\n",
364 rec, frame, frame->trylevel, descr, nested_frame );
365 dump_exception_type( exc_type );
366 dump_function_descr( descr, exc_type );
372 TRACE("handling C exception code %lx rec %p frame %p trylevel %d descr %p nested_frame %p\n",
373 rec->ExceptionCode, rec, frame, frame->trylevel, descr, nested_frame );
376 call_catch_block( rec, frame, descr, frame->trylevel, exc_type );
377 return ExceptionContinueSearch;
381 /*********************************************************************
382 * __CxxFrameHandler (MSVCRT.@)
384 extern DWORD __CxxFrameHandler( PEXCEPTION_RECORD rec, EXCEPTION_REGISTRATION_RECORD* frame,
385 PCONTEXT context, EXCEPTION_REGISTRATION_RECORD** dispatch );
386 __ASM_GLOBAL_FUNC( __CxxFrameHandler,
387 "pushl $0\n\t" /* nested_trylevel */
388 "pushl $0\n\t" /* nested_frame */
389 "pushl %eax\n\t" /* descr */
390 "pushl 28(%esp)\n\t" /* dispatch */
391 "pushl 28(%esp)\n\t" /* context */
392 "pushl 28(%esp)\n\t" /* frame */
393 "pushl 28(%esp)\n\t" /* rec */
394 "call " __ASM_NAME("cxx_frame_handler") "\n\t"
398 #endif /* __i386__ */
400 /*********************************************************************
401 * _CxxThrowException (MSVCRT.@)
403 void _CxxThrowException( exception *object, const cxx_exception_type *type )
407 args[0] = CXX_FRAME_MAGIC;
408 args[1] = (ULONG_PTR)object;
409 args[2] = (ULONG_PTR)type;
410 RaiseException( CXX_EXCEPTION, EH_NONCONTINUABLE, 3, args );
413 /*********************************************************************
414 * __CxxDetectRethrow (MSVCRT.@)
416 BOOL __CxxDetectRethrow(PEXCEPTION_POINTERS ptrs)
418 PEXCEPTION_RECORD rec;
423 rec = ptrs->ExceptionRecord;
425 if (rec->ExceptionCode == CXX_EXCEPTION &&
426 rec->NumberParameters == 3 &&
427 rec->ExceptionInformation[0] == CXX_FRAME_MAGIC &&
428 rec->ExceptionInformation[2])
430 ptrs->ExceptionRecord = msvcrt_get_thread_data()->exc_record;
433 return (msvcrt_get_thread_data()->exc_record == rec);
436 /*********************************************************************
437 * __CxxQueryExceptionSize (MSVCRT.@)
439 unsigned int __CxxQueryExceptionSize(void)
441 return sizeof(cxx_exception_type);