mshtml: Implement IHTMLWindow2::get_top.
[wine] / dlls / msvcrt / cppexcept.c
1 /*
2  * msvcrt C++ exception handling
3  *
4  * Copyright 2002 Alexandre Julliard
5  *
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.
10  *
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.
15  *
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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
19  *
20  * NOTES
21  * A good reference is the article "How a C++ compiler implements
22  * exception handling" by Vishal Kochhar, available on
23  * www.thecodeproject.com.
24  */
25
26 #include "config.h"
27 #include "wine/port.h"
28
29 #include <stdarg.h>
30
31 #include "windef.h"
32 #include "winbase.h"
33 #include "winternl.h"
34 #include "msvcrt.h"
35 #include "wine/exception.h"
36 #include "excpt.h"
37 #include "wine/debug.h"
38
39 #include "cppexcept.h"
40
41 #ifdef __i386__  /* CxxFrameHandler is not supported on non-i386 */
42
43 WINE_DEFAULT_DEBUG_CHANNEL(seh);
44
45 DWORD CDECL cxx_frame_handler( PEXCEPTION_RECORD rec, cxx_exception_frame* frame,
46                                PCONTEXT context, EXCEPTION_REGISTRATION_RECORD** dispatch,
47                                const cxx_function_descr *descr,
48                                EXCEPTION_REGISTRATION_RECORD* nested_frame, int nested_trylevel );
49
50 /* call a function with a given ebp */
51 static inline void *call_ebp_func( void *func, void *ebp )
52 {
53     void *ret;
54     int dummy;
55     __asm__ __volatile__ ("pushl %%ebx\n\t"
56                           "pushl %%ebp\n\t"
57                           "movl %4,%%ebp\n\t"
58                           "call *%%eax\n\t"
59                           "popl %%ebp\n\t"
60                           "popl %%ebx"
61                           : "=a" (ret), "=S" (dummy), "=D" (dummy)
62                           : "0" (func), "1" (ebp) : "ecx", "edx", "memory" );
63     return ret;
64 }
65
66 /* call a copy constructor */
67 static inline void call_copy_ctor( void *func, void *this, void *src, int has_vbase )
68 {
69     TRACE( "calling copy ctor %p object %p src %p\n", func, this, src );
70     if (has_vbase)
71         /* in that case copy ctor takes an extra bool indicating whether to copy the base class */
72         __asm__ __volatile__("pushl $1; pushl %2; call *%0"
73                              : : "r" (func), "c" (this), "r" (src) : "eax", "edx", "memory" );
74     else
75         __asm__ __volatile__("pushl %2; call *%0"
76                              : : "r" (func), "c" (this), "r" (src) : "eax", "edx", "memory" );
77 }
78
79 /* call the destructor of the exception object */
80 static inline void call_dtor( void *func, void *object )
81 {
82     __asm__ __volatile__("call *%0" : : "r" (func), "c" (object) : "eax", "edx", "memory" );
83 }
84
85 /* continue execution to the specified address after exception is caught */
86 static inline void DECLSPEC_NORETURN continue_after_catch( cxx_exception_frame* frame, void *addr )
87 {
88     __asm__ __volatile__("movl -4(%0),%%esp; leal 12(%0),%%ebp; jmp *%1"
89                          : : "r" (frame), "a" (addr) );
90     for (;;) ; /* unreached */
91 }
92
93 static inline void dump_type( const cxx_type_info *type )
94 {
95     TRACE( "flags %x type %p %s offsets %d,%d,%d size %d copy ctor %p\n",
96              type->flags, type->type_info, dbgstr_type_info(type->type_info),
97              type->offsets.this_offset, type->offsets.vbase_descr, type->offsets.vbase_offset,
98              type->size, type->copy_ctor );
99 }
100
101 static void dump_exception_type( const cxx_exception_type *type )
102 {
103     UINT i;
104
105     TRACE( "flags %x destr %p handler %p type info %p\n",
106              type->flags, type->destructor, type->custom_handler, type->type_info_table );
107     for (i = 0; i < type->type_info_table->count; i++)
108     {
109         TRACE( "    %d: ", i );
110         dump_type( type->type_info_table->info[i] );
111     }
112 }
113
114 static void dump_function_descr( const cxx_function_descr *descr )
115 {
116     UINT i;
117     int j;
118
119     TRACE( "magic %x\n", descr->magic );
120     TRACE( "unwind table: %p %d\n", descr->unwind_table, descr->unwind_count );
121     for (i = 0; i < descr->unwind_count; i++)
122     {
123         TRACE( "    %d: prev %d func %p\n", i,
124                  descr->unwind_table[i].prev, descr->unwind_table[i].handler );
125     }
126     TRACE( "try table: %p %d\n", descr->tryblock, descr->tryblock_count );
127     for (i = 0; i < descr->tryblock_count; i++)
128     {
129         TRACE( "    %d: start %d end %d catchlevel %d catch %p %d\n", i,
130                  descr->tryblock[i].start_level, descr->tryblock[i].end_level,
131                  descr->tryblock[i].catch_level, descr->tryblock[i].catchblock,
132                  descr->tryblock[i].catchblock_count );
133         for (j = 0; j < descr->tryblock[i].catchblock_count; j++)
134         {
135             const catchblock_info *ptr = &descr->tryblock[i].catchblock[j];
136             TRACE( "        %d: flags %x offset %d handler %p type %p %s\n",
137                      j, ptr->flags, ptr->offset, ptr->handler,
138                      ptr->type_info, dbgstr_type_info( ptr->type_info ) );
139         }
140     }
141 }
142
143 /* check if the exception type is caught by a given catch block, and return the type that matched */
144 static const cxx_type_info *find_caught_type( cxx_exception_type *exc_type,
145                                               const catchblock_info *catchblock )
146 {
147     UINT i;
148
149     for (i = 0; i < exc_type->type_info_table->count; i++)
150     {
151         const cxx_type_info *type = exc_type->type_info_table->info[i];
152
153         if (!catchblock->type_info) return type;   /* catch(...) matches any type */
154         if (catchblock->type_info != type->type_info)
155         {
156             if (strcmp( catchblock->type_info->mangled, type->type_info->mangled )) continue;
157         }
158         /* type is the same, now check the flags */
159         if ((exc_type->flags & TYPE_FLAG_CONST) &&
160             !(catchblock->flags & TYPE_FLAG_CONST)) continue;
161         if ((exc_type->flags & TYPE_FLAG_VOLATILE) &&
162             !(catchblock->flags & TYPE_FLAG_VOLATILE)) continue;
163         return type;  /* it matched */
164     }
165     return NULL;
166 }
167
168
169 /* copy the exception object where the catch block wants it */
170 static void copy_exception( void *object, cxx_exception_frame *frame,
171                             const catchblock_info *catchblock, const cxx_type_info *type )
172 {
173     void **dest_ptr;
174
175     if (!catchblock->type_info || !catchblock->type_info->mangled[0]) return;
176     if (!catchblock->offset) return;
177     dest_ptr = (void **)((char *)&frame->ebp + catchblock->offset);
178
179     if (catchblock->flags & TYPE_FLAG_REFERENCE)
180     {
181         *dest_ptr = get_this_pointer( &type->offsets, object );
182     }
183     else if (type->flags & CLASS_IS_SIMPLE_TYPE)
184     {
185         memmove( dest_ptr, object, type->size );
186         /* if it is a pointer, adjust it */
187         if (type->size == sizeof(void *)) *dest_ptr = get_this_pointer( &type->offsets, *dest_ptr );
188     }
189     else  /* copy the object */
190     {
191         if (type->copy_ctor)
192             call_copy_ctor( type->copy_ctor, dest_ptr, get_this_pointer(&type->offsets,object),
193                             (type->flags & CLASS_HAS_VIRTUAL_BASE_CLASS) );
194         else
195             memmove( dest_ptr, get_this_pointer(&type->offsets,object), type->size );
196     }
197 }
198
199 /* unwind the local function up to a given trylevel */
200 static void cxx_local_unwind( cxx_exception_frame* frame, const cxx_function_descr *descr, int last_level)
201 {
202     void (*handler)(void);
203     int trylevel = frame->trylevel;
204
205     while (trylevel != last_level)
206     {
207         if (trylevel < 0 || trylevel >= descr->unwind_count)
208         {
209             ERR( "invalid trylevel %d\n", trylevel );
210             MSVCRT_terminate();
211         }
212         handler = descr->unwind_table[trylevel].handler;
213         if (handler)
214         {
215             TRACE( "calling unwind handler %p trylevel %d last %d ebp %p\n",
216                    handler, trylevel, last_level, &frame->ebp );
217             call_ebp_func( handler, &frame->ebp );
218         }
219         trylevel = descr->unwind_table[trylevel].prev;
220     }
221     frame->trylevel = last_level;
222 }
223
224 /* exception frame for nested exceptions in catch block */
225 struct catch_func_nested_frame
226 {
227     EXCEPTION_REGISTRATION_RECORD frame;     /* standard exception frame */
228     EXCEPTION_RECORD             *prev_rec;  /* previous record to restore in thread data */
229     cxx_exception_frame          *cxx_frame; /* frame of parent exception */
230     const cxx_function_descr     *descr;     /* descriptor of parent exception */
231     int                           trylevel;  /* current try level */
232     EXCEPTION_RECORD             *rec;       /* rec associated with frame */
233 };
234
235 /* handler for exceptions happening while calling a catch function */
236 static DWORD catch_function_nested_handler( EXCEPTION_RECORD *rec, EXCEPTION_REGISTRATION_RECORD *frame,
237                                             CONTEXT *context, EXCEPTION_REGISTRATION_RECORD **dispatcher )
238 {
239     struct catch_func_nested_frame *nested_frame = (struct catch_func_nested_frame *)frame;
240
241     if (rec->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND))
242     {
243         msvcrt_get_thread_data()->exc_record = nested_frame->prev_rec;
244         return ExceptionContinueSearch;
245     }
246
247     TRACE( "got nested exception in catch function\n" );
248
249     if(rec->ExceptionCode == CXX_EXCEPTION)
250     {
251         PEXCEPTION_RECORD prev_rec = nested_frame->rec;
252         if(rec->ExceptionInformation[1] == 0 && rec->ExceptionInformation[2] == 0)
253         {
254             /* exception was rethrown */
255             rec->ExceptionInformation[1] = prev_rec->ExceptionInformation[1];
256             rec->ExceptionInformation[2] = prev_rec->ExceptionInformation[2];
257             TRACE("detect rethrow: re-propagate: obj: %lx, type: %lx\n",
258                     rec->ExceptionInformation[1], rec->ExceptionInformation[2]);
259         }
260         else {
261             /* new exception in exception handler, destroy old */
262             void *object = (void*)prev_rec->ExceptionInformation[1];
263             cxx_exception_type *info = (cxx_exception_type*) prev_rec->ExceptionInformation[2];
264             TRACE("detect threw new exception in catch block - destroy old(obj: %p type: %p)\n",
265                     object, info);
266             if(info && info->destructor)
267                 call_dtor( info->destructor, object );
268         }
269     }
270
271     return cxx_frame_handler( rec, nested_frame->cxx_frame, context,
272                               NULL, nested_frame->descr, &nested_frame->frame,
273                               nested_frame->trylevel );
274 }
275
276 /* find and call the appropriate catch block for an exception */
277 /* returns the address to continue execution to after the catch block was called */
278 static inline void call_catch_block( PEXCEPTION_RECORD rec, cxx_exception_frame *frame,
279                                      const cxx_function_descr *descr, int nested_trylevel,
280                                      cxx_exception_type *info )
281 {
282     UINT i;
283     int j;
284     void *addr, *object = (void *)rec->ExceptionInformation[1];
285     struct catch_func_nested_frame nested_frame;
286     int trylevel = frame->trylevel;
287     thread_data_t *thread_data = msvcrt_get_thread_data();
288     DWORD save_esp = ((DWORD*)frame)[-1];
289
290     for (i = 0; i < descr->tryblock_count; i++)
291     {
292         const tryblock_info *tryblock = &descr->tryblock[i];
293
294         if (trylevel < tryblock->start_level) continue;
295         if (trylevel > tryblock->end_level) continue;
296
297         /* got a try block */
298         for (j = 0; j < tryblock->catchblock_count; j++)
299         {
300             const catchblock_info *catchblock = &tryblock->catchblock[j];
301             if(info)
302             {
303                 const cxx_type_info *type = find_caught_type( info, catchblock );
304                 if (!type) continue;
305
306                 TRACE( "matched type %p in tryblock %d catchblock %d\n", type, i, j );
307
308                 /* copy the exception to its destination on the stack */
309                 copy_exception( object, frame, catchblock, type );
310             }
311             else
312             {
313                 /* no CXX_EXCEPTION only proceed with a catch(...) block*/
314                 if(catchblock->type_info)
315                     continue;
316                 TRACE("found catch(...) block\n");
317             }
318
319             /* unwind the stack */
320             RtlUnwind( frame, 0, rec, 0 );
321             cxx_local_unwind( frame, descr, tryblock->start_level );
322             frame->trylevel = tryblock->end_level + 1;
323
324             /* call the catch block */
325             TRACE( "calling catch block %p addr %p ebp %p\n",
326                    catchblock, catchblock->handler, &frame->ebp );
327
328             /* setup an exception block for nested exceptions */
329
330             nested_frame.frame.Handler = catch_function_nested_handler;
331             nested_frame.prev_rec  = thread_data->exc_record;
332             nested_frame.cxx_frame = frame;
333             nested_frame.descr     = descr;
334             nested_frame.trylevel  = nested_trylevel + 1;
335             nested_frame.rec = rec;
336
337             __wine_push_frame( &nested_frame.frame );
338             thread_data->exc_record = rec;
339             addr = call_ebp_func( catchblock->handler, &frame->ebp );
340             thread_data->exc_record = nested_frame.prev_rec;
341             __wine_pop_frame( &nested_frame.frame );
342
343             ((DWORD*)frame)[-1] = save_esp;
344             if (info && info->destructor) call_dtor( info->destructor, object );
345             TRACE( "done, continuing at %p\n", addr );
346
347             continue_after_catch( frame, addr );
348         }
349     }
350 }
351
352
353 /*********************************************************************
354  *              cxx_frame_handler
355  *
356  * Implementation of __CxxFrameHandler.
357  */
358 DWORD CDECL cxx_frame_handler( PEXCEPTION_RECORD rec, cxx_exception_frame* frame,
359                                PCONTEXT context, EXCEPTION_REGISTRATION_RECORD** dispatch,
360                                const cxx_function_descr *descr,
361                                EXCEPTION_REGISTRATION_RECORD* nested_frame,
362                                int nested_trylevel )
363 {
364     cxx_exception_type *exc_type;
365
366     if (descr->magic != CXX_FRAME_MAGIC)
367     {
368         ERR( "invalid frame magic %x\n", descr->magic );
369         return ExceptionContinueSearch;
370     }
371     if (rec->ExceptionFlags & (EH_UNWINDING|EH_EXIT_UNWIND))
372     {
373         if (descr->unwind_count && !nested_trylevel) cxx_local_unwind( frame, descr, -1 );
374         return ExceptionContinueSearch;
375     }
376     if (!descr->tryblock_count) return ExceptionContinueSearch;
377
378     if(rec->ExceptionCode == CXX_EXCEPTION)
379     {
380         exc_type = (cxx_exception_type *)rec->ExceptionInformation[2];
381
382         if (rec->ExceptionInformation[0] > CXX_FRAME_MAGIC &&
383                 exc_type->custom_handler)
384         {
385             return exc_type->custom_handler( rec, frame, context, dispatch,
386                                          descr, nested_trylevel, nested_frame, 0 );
387         }
388
389         if (TRACE_ON(seh))
390         {
391             TRACE("handling C++ exception rec %p frame %p trylevel %d descr %p nested_frame %p\n",
392                   rec, frame, frame->trylevel, descr, nested_frame );
393             dump_exception_type( exc_type );
394             dump_function_descr( descr );
395         }
396     }
397     else
398     {
399         exc_type = NULL;
400         TRACE("handling C exception code %x  rec %p frame %p trylevel %d descr %p nested_frame %p\n",
401               rec->ExceptionCode,  rec, frame, frame->trylevel, descr, nested_frame );
402     }
403
404     call_catch_block( rec, frame, descr, frame->trylevel, exc_type );
405     return ExceptionContinueSearch;
406 }
407
408
409 /*********************************************************************
410  *              __CxxFrameHandler (MSVCRT.@)
411  */
412 extern DWORD CDECL __CxxFrameHandler( PEXCEPTION_RECORD rec, EXCEPTION_REGISTRATION_RECORD* frame,
413                                       PCONTEXT context, EXCEPTION_REGISTRATION_RECORD** dispatch );
414 __ASM_GLOBAL_FUNC( __CxxFrameHandler,
415                    "pushl $0\n\t"        /* nested_trylevel */
416                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
417                    "pushl $0\n\t"        /* nested_frame */
418                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
419                    "pushl %eax\n\t"      /* descr */
420                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
421                    "pushl 28(%esp)\n\t"  /* dispatch */
422                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
423                    "pushl 28(%esp)\n\t"  /* context */
424                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
425                    "pushl 28(%esp)\n\t"  /* frame */
426                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
427                    "pushl 28(%esp)\n\t"  /* rec */
428                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
429                    "call " __ASM_NAME("cxx_frame_handler") "\n\t"
430                    "add $28,%esp\n\t"
431                    __ASM_CFI(".cfi_adjust_cfa_offset -28\n\t")
432                    "ret" )
433
434
435 /*********************************************************************
436  *              __CxxLongjmpUnwind (MSVCRT.@)
437  *
438  * Callback meant to be used as UnwindFunc for setjmp/longjmp.
439  */
440 void __stdcall __CxxLongjmpUnwind( const struct MSVCRT___JUMP_BUFFER *buf )
441 {
442     cxx_exception_frame *frame = (cxx_exception_frame *)buf->Registration;
443     const cxx_function_descr *descr = (const cxx_function_descr *)buf->UnwindData[0];
444
445     TRACE( "unwinding frame %p descr %p trylevel %ld\n", frame, descr, buf->TryLevel );
446     cxx_local_unwind( frame, descr, buf->TryLevel );
447 }
448
449 #endif  /* __i386__ */
450
451
452 /*********************************************************************
453  *              __CppXcptFilter (MSVCRT.@)
454  */
455 int CDECL __CppXcptFilter(NTSTATUS ex, PEXCEPTION_POINTERS ptr)
456 {
457     /* only filter c++ exceptions */
458     if (ex != CXX_EXCEPTION) return EXCEPTION_CONTINUE_SEARCH;
459     return _XcptFilter( ex, ptr );
460 }
461
462 /*********************************************************************
463  *              _CxxThrowException (MSVCRT.@)
464  */
465 void CDECL _CxxThrowException( exception *object, const cxx_exception_type *type )
466 {
467     ULONG_PTR args[3];
468
469     args[0] = CXX_FRAME_MAGIC;
470     args[1] = (ULONG_PTR)object;
471     args[2] = (ULONG_PTR)type;
472     RaiseException( CXX_EXCEPTION, EH_NONCONTINUABLE, 3, args );
473 }
474
475 /*********************************************************************
476  *              __CxxDetectRethrow (MSVCRT.@)
477  */
478 BOOL CDECL __CxxDetectRethrow(PEXCEPTION_POINTERS ptrs)
479 {
480   PEXCEPTION_RECORD rec;
481
482   if (!ptrs)
483     return FALSE;
484
485   rec = ptrs->ExceptionRecord;
486
487   if (rec->ExceptionCode == CXX_EXCEPTION &&
488       rec->NumberParameters == 3 &&
489       rec->ExceptionInformation[0] == CXX_FRAME_MAGIC &&
490       rec->ExceptionInformation[2])
491   {
492     ptrs->ExceptionRecord = msvcrt_get_thread_data()->exc_record;
493     return TRUE;
494   }
495   return (msvcrt_get_thread_data()->exc_record == rec);
496 }
497
498 /*********************************************************************
499  *              __CxxQueryExceptionSize (MSVCRT.@)
500  */
501 unsigned int CDECL __CxxQueryExceptionSize(void)
502 {
503   return sizeof(cxx_exception_type);
504 }