lib/sdk/crt/except/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 #define __WINE_DEBUG_CHANNEL__
  27 #include <precomp.h>
  28 #include <stdarg.h>
  29
  30 #include <wine/exception.h>
  31 #include <internal/wine/msvcrt.h>
  32 #include <internal/wine/cppexcept.h>
  33
  34 #ifdef __i386__  /* CxxFrameHandler is not supported on non-i386 */
  35
  36 WINE_DEFAULT_DEBUG_CHANNEL(seh);
  37
  38 DWORD CDECL cxx_frame_handler( PEXCEPTION_RECORD rec, cxx_exception_frame* frame,
  39                                PCONTEXT context, EXCEPTION_REGISTRATION_RECORD** dispatch,
  40                                const cxx_function_descr *descr,
  41                                EXCEPTION_REGISTRATION_RECORD* nested_frame, int nested_trylevel );
  42
  43 /* call a function with a given ebp */
  44 static inline void *call_ebp_func( void *func, void *ebp )
  45 {
  46     void *ret;
  47     int dummy;
  48     __asm__ __volatile__ ("pushl %%ebx\n\t"
  49                           "pushl %%ebp\n\t"
  50                           "movl %4,%%ebp\n\t"
  51                           "call *%%eax\n\t"
  52                           "popl %%ebp\n\t"
  53                           "popl %%ebx"
  54                           : "=a" (ret), "=S" (dummy), "=D" (dummy)
  55                           : "0" (func), "1" (ebp) : "ecx", "edx", "memory" );
  56     return ret;
  57 }
  58
  59 /* call a copy constructor */
  60 static inline void call_copy_ctor( void *func, void *this, void *src, int has_vbase )
  61 {
  62     TRACE( "calling copy ctor %p object %p src %p\n", func, this, src );
  63     if (has_vbase)
  64         /* in that case copy ctor takes an extra bool indicating whether to copy the base class */
  65         __asm__ __volatile__("pushl $1; pushl %2; call *%0"
  66                              : : "r" (func), "c" (this), "r" (src) : "eax", "edx", "memory" );
  67     else
  68         __asm__ __volatile__("pushl %2; call *%0"
  69                              : : "r" (func), "c" (this), "r" (src) : "eax", "edx", "memory" );
  70 }
  71
  72 /* call the destructor of the exception object */
  73 static inline void call_dtor( void *func, void *object )
  74 {
  75     __asm__ __volatile__("call *%0" : : "r" (func), "c" (object) : "eax", "edx", "memory" );
  76 }
  77
  78 /* continue execution to the specified address after exception is caught */
  79 static inline void DECLSPEC_NORETURN continue_after_catch( cxx_exception_frame* frame, void *addr )
  80 {
  81     __asm__ __volatile__("movl -4(%0),%%esp; leal 12(%0),%%ebp; jmp *%1"
  82                          : : "r" (frame), "a" (addr) );
  83     for (;;) ; /* unreached */
  84 }
  85
  86 static inline void dump_type( const cxx_type_info *type )
  87 {
  88     TRACE( "flags %x type %p %s offsets %d,%d,%d size %d copy ctor %p\n",
  89              type->flags, type->type_info, dbgstr_type_info(type->type_info),
  90              type->offsets.this_offset, type->offsets.vbase_descr, type->offsets.vbase_offset,
  91              type->size, type->copy_ctor );
  92 }
  93
  94 static void dump_exception_type( const cxx_exception_type *type )
  95 {
  96     UINT i;
  97
  98     TRACE( "flags %x destr %p handler %p type info %p\n",
  99              type->flags, type->destructor, type->custom_handler, type->type_info_table );
 100     for (i = 0; i < type->type_info_table->count; i++)
 101     {
 102         TRACE( "    %d: ", i );
 103         dump_type( type->type_info_table->info[i] );
 104     }
 105 }
 106
 107 static void dump_function_descr( const cxx_function_descr *descr )
 108 {
 109 #ifndef WINE_NO_TRACE_MSGS
 110     UINT i;
 111     int j;
 112
 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++)
 116     {
 117         TRACE( "    %d: prev %d func %p\n", i,
 118                  descr->unwind_table[i].prev, descr->unwind_table[i].handler );
 119     }
 120     TRACE( "try table: %p %d\n", descr->tryblock, descr->tryblock_count );
 121     for (i = 0; i < descr->tryblock_count; i++)
 122     {
 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++)
 128         {
 129             const 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 ) );
 133         }
 134     }
 135 #endif
 136     if (descr->magic <= CXX_FRAME_MAGIC_VC6) return;
 137     TRACE( "expect list: %p\n", descr->expect_list );
 138     if (descr->magic <= CXX_FRAME_MAGIC_VC7) return;
 139     TRACE( "flags: %08x\n", descr->flags );
 140 }
 141
 142 /* check if the exception type is caught by a given catch block, and return the type that matched */
 143 static const cxx_type_info *find_caught_type( cxx_exception_type *exc_type,
 144                                               const catchblock_info *catchblock )
 145 {
 146     UINT i;
 147
 148     for (i = 0; i < exc_type->type_info_table->count; i++)
 149     {
 150         const cxx_type_info *type = exc_type->type_info_table->info[i];
 151
 152         if (!catchblock->type_info) return type;   /* catch(...) matches any type */
 153         if (catchblock->type_info != type->type_info)
 154         {
 155             if (strcmp( catchblock->type_info->mangled, type->type_info->mangled )) continue;
 156         }
 157         /* type is the same, now check the flags */
 158         if ((exc_type->flags & TYPE_FLAG_CONST) &&
 159             !(catchblock->flags & TYPE_FLAG_CONST)) continue;
 160         if ((exc_type->flags & TYPE_FLAG_VOLATILE) &&
 161             !(catchblock->flags & TYPE_FLAG_VOLATILE)) continue;
 162         return type;  /* it matched */
 163     }
 164     return NULL;
 165 }
 166
 167
 168 /* copy the exception object where the catch block wants it */
 169 static void copy_exception( void *object, cxx_exception_frame *frame,
 170                             const catchblock_info *catchblock, const cxx_type_info *type )
 171 {
 172     void **dest_ptr;
 173
 174     if (!catchblock->type_info || !catchblock->type_info->mangled[0]) return;
 175     if (!catchblock->offset) return;
 176     dest_ptr = (void **)((char *)&frame->ebp + catchblock->offset);
 177
 178     if (catchblock->flags & TYPE_FLAG_REFERENCE)
 179     {
 180         *dest_ptr = get_this_pointer( &type->offsets, object );
 181     }
 182     else if (type->flags & CLASS_IS_SIMPLE_TYPE)
 183     {
 184         memmove( dest_ptr, object, type->size );
 185         /* if it is a pointer, adjust it */
 186         if (type->size == sizeof(void *)) *dest_ptr = get_this_pointer( &type->offsets, *dest_ptr );
 187     }
 188     else  /* copy the object */
 189     {
 190         if (type->copy_ctor)
 191             call_copy_ctor( type->copy_ctor, dest_ptr, get_this_pointer(&type->offsets,object),
 192                             (type->flags & CLASS_HAS_VIRTUAL_BASE_CLASS) );
 193         else
 194             memmove( dest_ptr, get_this_pointer(&type->offsets,object), type->size );
 195     }
 196 }
 197
 198 /* unwind the local function up to a given trylevel */
 199 static void cxx_local_unwind( cxx_exception_frame* frame, const cxx_function_descr *descr, int last_level)
 200 {
 201     void (*handler)(void);
 202     int trylevel = frame->trylevel;
 203
 204     while (trylevel != last_level)
 205     {
 206         if (trylevel < 0 || trylevel >= descr->unwind_count)
 207         {
 208             ERR( "invalid trylevel %d\n", trylevel );
 209             MSVCRT_terminate();
 210         }
 211         handler = descr->unwind_table[trylevel].handler;
 212         if (handler)
 213         {
 214             TRACE( "calling unwind handler %p trylevel %d last %d ebp %p\n",
 215                    handler, trylevel, last_level, &frame->ebp );
 216             call_ebp_func( handler, &frame->ebp );
 217         }
 218         trylevel = descr->unwind_table[trylevel].prev;
 219     }
 220     frame->trylevel = last_level;
 221 }
 222
 223 /* exception frame for nested exceptions in catch block */
 224 struct catch_func_nested_frame
 225 {
 226     EXCEPTION_REGISTRATION_RECORD frame;     /* standard exception frame */
 227     EXCEPTION_RECORD             *prev_rec;  /* previous record to restore in thread data */
 228     cxx_exception_frame          *cxx_frame; /* frame of parent exception */
 229     const cxx_function_descr     *descr;     /* descriptor of parent exception */
 230     int                           trylevel;  /* current try level */
 231     EXCEPTION_RECORD             *rec;       /* rec associated with frame */
 232 };
 233
 234 /* handler for exceptions happening while calling a catch function */
 235 static DWORD catch_function_nested_handler( EXCEPTION_RECORD *rec, EXCEPTION_REGISTRATION_RECORD *frame,
 236                                             CONTEXT *context, EXCEPTION_REGISTRATION_RECORD **dispatcher )
 237 {
 238     struct catch_func_nested_frame *nested_frame = (struct catch_func_nested_frame *)frame;
 239
 240     if (rec->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND))
 241     {
 242         msvcrt_get_thread_data()->exc_record = nested_frame->prev_rec;
 243         return ExceptionContinueSearch;
 244     }
 245
 246     TRACE( "got nested exception in catch function\n" );
 247
 248     if(rec->ExceptionCode == CXX_EXCEPTION)
 249     {
 250         PEXCEPTION_RECORD prev_rec = nested_frame->rec;
 251         if(rec->ExceptionInformation[1] == 0 && rec->ExceptionInformation[2] == 0)
 252         {
 253             /* exception was rethrown */
 254             rec->ExceptionInformation[1] = prev_rec->ExceptionInformation[1];
 255             rec->ExceptionInformation[2] = prev_rec->ExceptionInformation[2];
 256             TRACE("detect rethrow: re-propagate: obj: %lx, type: %lx\n",
 257                     rec->ExceptionInformation[1], rec->ExceptionInformation[2]);
 258         }
 259         else {
 260             /* new exception in exception handler, destroy old */
 261             void *object = (void*)prev_rec->ExceptionInformation[1];
 262             cxx_exception_type *info = (cxx_exception_type*) prev_rec->ExceptionInformation[2];
 263             TRACE("detect threw new exception in catch block - destroy old(obj: %p type: %p)\n",
 264                     object, info);
 265             if(info && info->destructor)
 266                 call_dtor( info->destructor, object );
 267         }
 268     }
 269
 270     return cxx_frame_handler( rec, nested_frame->cxx_frame, context,
 271                               NULL, nested_frame->descr, &nested_frame->frame,
 272                               nested_frame->trylevel );
 273 }
 274
 275 /* find and call the appropriate catch block for an exception */
 276 /* returns the address to continue execution to after the catch block was called */
 277 static inline void call_catch_block( PEXCEPTION_RECORD rec, cxx_exception_frame *frame,
 278                                      const cxx_function_descr *descr, int nested_trylevel,
 279                                      cxx_exception_type *info )
 280 {
 281     UINT i;
 282     int j;
 283     void *addr, *object = (void *)rec->ExceptionInformation[1];
 284     struct catch_func_nested_frame nested_frame;
 285     int trylevel = frame->trylevel;
 286     MSVCRT_thread_data *thread_data = msvcrt_get_thread_data();
 287     DWORD save_esp = ((DWORD*)frame)[-1];
 288
 289     for (i = 0; i < descr->tryblock_count; i++)
 290     {
 291         const tryblock_info *tryblock = &descr->tryblock[i];
 292
 293         if (trylevel < tryblock->start_level) continue;
 294         if (trylevel > tryblock->end_level) continue;
 295
 296         /* got a try block */
 297         for (j = 0; j < tryblock->catchblock_count; j++)
 298         {
 299             const catchblock_info *catchblock = &tryblock->catchblock[j];
 300             if(info)
 301             {
 302                 const cxx_type_info *type = find_caught_type( info, catchblock );
 303                 if (!type) continue;
 304
 305                 TRACE( "matched type %p in tryblock %d catchblock %d\n", type, i, j );
 306
 307                 /* copy the exception to its destination on the stack */
 308                 copy_exception( object, frame, catchblock, type );
 309             }
 310             else
 311             {
 312                 /* no CXX_EXCEPTION only proceed with a catch(...) block*/
 313                 if(catchblock->type_info)
 314                     continue;
 315                 TRACE("found catch(...) block\n");
 316             }
 317
 318             /* unwind the stack */
 319             RtlUnwind( frame, 0, rec, 0 );
 320             cxx_local_unwind( frame, descr, tryblock->start_level );
 321             frame->trylevel = tryblock->end_level + 1;
 322
 323             /* call the catch block */
 324             TRACE( "calling catch block %p addr %p ebp %p\n",
 325                    catchblock, catchblock->handler, &frame->ebp );
 326
 327             /* setup an exception block for nested exceptions */
 328
 329             nested_frame.frame.Handler = (PEXCEPTION_ROUTINE)catch_function_nested_handler;
 330             nested_frame.prev_rec  = thread_data->exc_record;
 331             nested_frame.cxx_frame = frame;
 332             nested_frame.descr     = descr;
 333             nested_frame.trylevel  = nested_trylevel + 1;
 334             nested_frame.rec = rec;
 335
 336             __wine_push_frame( &nested_frame.frame );
 337             thread_data->exc_record = rec;
 338             addr = call_ebp_func( catchblock->handler, &frame->ebp );
 339             thread_data->exc_record = nested_frame.prev_rec;
 340             __wine_pop_frame( &nested_frame.frame );
 341
 342             ((DWORD*)frame)[-1] = save_esp;
 343             if (info && info->destructor) call_dtor( info->destructor, object );
 344             TRACE( "done, continuing at %p\n", addr );
 345
 346             continue_after_catch( frame, addr );
 347         }
 348     }
 349 }
 350
 351
 352 /*********************************************************************
 353  *              cxx_frame_handler
 354  *
 355  * Implementation of __CxxFrameHandler.
 356  */
 357 DWORD CDECL cxx_frame_handler( PEXCEPTION_RECORD rec, cxx_exception_frame* frame,
 358                                PCONTEXT context, EXCEPTION_REGISTRATION_RECORD** dispatch,
 359                                const cxx_function_descr *descr,
 360                                EXCEPTION_REGISTRATION_RECORD* nested_frame,
 361                                int nested_trylevel )
 362 {
 363     cxx_exception_type *exc_type;
 364
 365     if (descr->magic < CXX_FRAME_MAGIC_VC6 || descr->magic > CXX_FRAME_MAGIC_VC8)
 366     {
 367         ERR( "invalid frame magic %x\n", descr->magic );
 368         return ExceptionContinueSearch;
 369     }
 370     if (descr->magic >= CXX_FRAME_MAGIC_VC8 &&
 371         (descr->flags & FUNC_DESCR_SYNCHRONOUS) &&
 372         (rec->ExceptionCode != CXX_EXCEPTION))
 373         return ExceptionContinueSearch;  /* handle only c++ exceptions */
 374
 375     if (rec->ExceptionFlags & (EH_UNWINDING|EH_EXIT_UNWIND))
 376     {
 377         if (descr->unwind_count && !nested_trylevel) cxx_local_unwind( frame, descr, -1 );
 378         return ExceptionContinueSearch;
 379     }
 380     if (!descr->tryblock_count) return ExceptionContinueSearch;
 381
 382     if(rec->ExceptionCode == CXX_EXCEPTION)
 383     {
 384         exc_type = (cxx_exception_type *)rec->ExceptionInformation[2];
 385
 386         if (rec->ExceptionInformation[0] > CXX_FRAME_MAGIC_VC8 &&
 387                 exc_type->custom_handler)
 388         {
 389             return exc_type->custom_handler( rec, frame, context, dispatch,
 390                                          descr, nested_trylevel, nested_frame, 0 );
 391         }
 392
 393         if (TRACE_ON(seh))
 394         {
 395             TRACE("handling C++ exception rec %p frame %p trylevel %d descr %p nested_frame %p\n",
 396                   rec, frame, frame->trylevel, descr, nested_frame );
 397             dump_exception_type( exc_type );
 398             dump_function_descr( descr );
 399         }
 400     }
 401     else
 402     {
 403         exc_type = NULL;
 404         TRACE("handling C exception code %x  rec %p frame %p trylevel %d descr %p nested_frame %p\n",
 405               rec->ExceptionCode,  rec, frame, frame->trylevel, descr, nested_frame );
 406     }
 407
 408     call_catch_block( rec, frame, descr, frame->trylevel, exc_type );
 409     return ExceptionContinueSearch;
 410 }
 411
 412
 413 /*********************************************************************
 414  *              __CxxFrameHandler (MSVCRT.@)
 415  */
 416 extern DWORD CDECL __CxxFrameHandler( PEXCEPTION_RECORD rec, EXCEPTION_REGISTRATION_RECORD* frame,
 417                                       PCONTEXT context, EXCEPTION_REGISTRATION_RECORD** dispatch );
 418 __ASM_GLOBAL_FUNC( __CxxFrameHandler,
 419                    "pushl $0\n\t"        /* nested_trylevel */
 420                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
 421                    "pushl $0\n\t"        /* nested_frame */
 422                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
 423                    "pushl %eax\n\t"      /* descr */
 424                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
 425                    "pushl 28(%esp)\n\t"  /* dispatch */
 426                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
 427                    "pushl 28(%esp)\n\t"  /* context */
 428                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
 429                    "pushl 28(%esp)\n\t"  /* frame */
 430                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
 431                    "pushl 28(%esp)\n\t"  /* rec */
 432                    __ASM_CFI(".cfi_adjust_cfa_offset 4\n\t")
 433                    "call " __ASM_NAME("cxx_frame_handler") "\n\t"
 434                    "add $28,%esp\n\t"
 435                    __ASM_CFI(".cfi_adjust_cfa_offset -28\n\t")
 436                    "ret" )
 437
 438
 439 /*********************************************************************
 440  *              __CxxLongjmpUnwind (MSVCRT.@)
 441  *
 442  * Callback meant to be used as UnwindFunc for setjmp/longjmp.
 443  */
 444 void __stdcall __CxxLongjmpUnwind( const struct MSVCRT___JUMP_BUFFER *buf )
 445 {
 446     cxx_exception_frame *frame = (cxx_exception_frame *)buf->Registration;
 447     const cxx_function_descr *descr = (const cxx_function_descr *)buf->UnwindData[0];
 448
 449     TRACE( "unwinding frame %p descr %p trylevel %ld\n", frame, descr, buf->TryLevel );
 450     cxx_local_unwind( frame, descr, buf->TryLevel );
 451 }
 452
 453 #endif  /* __i386__ */
 454
 455
 456 /*********************************************************************
 457  *              __CppXcptFilter (MSVCRT.@)
 458  */
 459 int CDECL __CppXcptFilter(NTSTATUS ex, PEXCEPTION_POINTERS ptr)
 460 {
 461     /* only filter c++ exceptions */
 462     if (ex != CXX_EXCEPTION) return EXCEPTION_CONTINUE_SEARCH;
 463     return _XcptFilter( ex, ptr );
 464 }
 465
 466 /*********************************************************************
 467  *              _CxxThrowException (MSVCRT.@)
 468  */
 469 void CDECL _CxxThrowException( exception *object, const cxx_exception_type *type )
 470 {
 471     ULONG_PTR args[3];
 472
 473     args[0] = CXX_FRAME_MAGIC_VC6;
 474     args[1] = (ULONG_PTR)object;
 475     args[2] = (ULONG_PTR)type;
 476     RaiseException( CXX_EXCEPTION, EH_NONCONTINUABLE, 3, args );
 477 }
 478
 479 /*********************************************************************
 480  *              __CxxDetectRethrow (MSVCRT.@)
 481  */
 482 BOOL CDECL __CxxDetectRethrow(PEXCEPTION_POINTERS ptrs)
 483 {
 484   PEXCEPTION_RECORD rec;
 485
 486   if (!ptrs)
 487     return FALSE;
 488
 489   rec = ptrs->ExceptionRecord;
 490
 491   if (rec->ExceptionCode == CXX_EXCEPTION &&
 492       rec->NumberParameters == 3 &&
 493       rec->ExceptionInformation[0] == CXX_FRAME_MAGIC_VC6 &&
 494       rec->ExceptionInformation[2])
 495   {
 496     ptrs->ExceptionRecord = msvcrt_get_thread_data()->exc_record;
 497     return TRUE;
 498   }
 499   return (msvcrt_get_thread_data()->exc_record == rec);
 500 }
 501
 502 /*********************************************************************
 503  *              __CxxQueryExceptionSize (MSVCRT.@)
 504  */
 505 unsigned int CDECL __CxxQueryExceptionSize(void)
 506 {
 507   return sizeof(cxx_exception_type);
 508 }