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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  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 "winreg.h"
  34 #include "winternl.h"
  35 #include "msvcrt.h"
  36 #include "wine/exception.h"
  37 #include "excpt.h"
  38 #include "wine/debug.h"
  39
  40 #include "cppexcept.h"
  41
  42 WINE_DEFAULT_DEBUG_CHANNEL(seh);
  43
  44 #ifdef __i386__  /* CxxFrameHandler is not supported on non-i386 */
  45
  46 static DWORD cxx_frame_handler( PEXCEPTION_RECORD rec, cxx_exception_frame* frame,
  47                                 PCONTEXT exc_context, EXCEPTION_REGISTRATION_RECORD** dispatch,
  48                                 cxx_function_descr *descr, EXCEPTION_REGISTRATION_RECORD* nested_frame,
  49                                 int nested_trylevel, CONTEXT86 *context );
  50
  51 /* call a function with a given ebp */
  52 inline static void *call_ebp_func( void *func, void *ebp )
  53 {
  54     void *ret;
  55     __asm__ __volatile__ ("pushl %%ebp; movl %2,%%ebp; call *%%eax; popl %%ebp" \
  56                           : "=a" (ret) : "0" (func), "r" (ebp) : "ecx", "edx", "memory" );
  57     return ret;
  58 }
  59
  60 /* call a copy constructor */
  61 inline static void call_copy_ctor( void *func, void *this, void *src, int has_vbase )
  62 {
  63     TRACE( "calling copy ctor %p object %p src %p\n", func, this, src );
  64     if (has_vbase)
  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" );
  68     else
  69         __asm__ __volatile__("pushl %2; call *%0"
  70                              : : "r" (func), "c" (this), "r" (src) : "eax", "edx", "memory" );
  71 }
  72
  73 /* call the destructor of the exception object */
  74 inline static void call_dtor( void *func, void *object )
  75 {
  76     __asm__ __volatile__("call *%0" : : "r" (func), "c" (object) : "eax", "edx", "memory" );
  77 }
  78
  79 static inline void dump_type( const cxx_type_info *type )
  80 {
  81     TRACE( "flags %x type %p %s offsets %d,%d,%d size %d copy ctor %p\n",
  82              type->flags, type->type_info, dbgstr_type_info(type->type_info),
  83              type->offsets.this_offset, type->offsets.vbase_descr, type->offsets.vbase_offset,
  84              type->size, type->copy_ctor );
  85 }
  86
  87 static void dump_exception_type( const cxx_exception_type *type )
  88 {
  89     UINT i;
  90
  91     TRACE( "flags %x destr %p handler %p type info %p\n",
  92              type->flags, type->destructor, type->custom_handler, type->type_info_table );
  93     for (i = 0; i < type->type_info_table->count; i++)
  94     {
  95         TRACE( "    %d: ", i );
  96         dump_type( type->type_info_table->info[i] );
  97     }
  98 }
  99
 100 static void dump_function_descr( const cxx_function_descr *descr, const cxx_exception_type *info )
 101 {
 102     UINT i;
 103     int j;
 104
 105     TRACE( "magic %x\n", descr->magic );
 106     TRACE( "unwind table: %p %d\n", descr->unwind_table, descr->unwind_count );
 107     for (i = 0; i < descr->unwind_count; i++)
 108     {
 109         TRACE( "    %d: prev %d func %p\n", i,
 110                  descr->unwind_table[i].prev, descr->unwind_table[i].handler );
 111     }
 112     TRACE( "try table: %p %d\n", descr->tryblock, descr->tryblock_count );
 113     for (i = 0; i < descr->tryblock_count; i++)
 114     {
 115         TRACE( "    %d: start %d end %d catchlevel %d catch %p %d\n", i,
 116                  descr->tryblock[i].start_level, descr->tryblock[i].end_level,
 117                  descr->tryblock[i].catch_level, descr->tryblock[i].catchblock,
 118                  descr->tryblock[i].catchblock_count );
 119         for (j = 0; j < descr->tryblock[i].catchblock_count; j++)
 120         {
 121             catchblock_info *ptr = &descr->tryblock[i].catchblock[j];
 122             TRACE( "        %d: flags %x offset %d handler %p type %p %s\n",
 123                      j, ptr->flags, ptr->offset, ptr->handler,
 124                      ptr->type_info, dbgstr_type_info( ptr->type_info ) );
 125         }
 126     }
 127 }
 128
 129 /* check if the exception type is caught by a given catch block, and return the type that matched */
 130 static const cxx_type_info *find_caught_type( cxx_exception_type *exc_type, catchblock_info *catchblock )
 131 {
 132     UINT i;
 133
 134     for (i = 0; i < exc_type->type_info_table->count; i++)
 135     {
 136         const cxx_type_info *type = exc_type->type_info_table->info[i];
 137
 138         if (!catchblock->type_info) return type;   /* catch(...) matches any type */
 139         if (catchblock->type_info != type->type_info)
 140         {
 141             if (strcmp( catchblock->type_info->mangled, type->type_info->mangled )) continue;
 142         }
 143         /* type is the same, now check the flags */
 144         if ((exc_type->flags & TYPE_FLAG_CONST) &&
 145             !(catchblock->flags & TYPE_FLAG_CONST)) continue;
 146         if ((exc_type->flags & TYPE_FLAG_VOLATILE) &&
 147             !(catchblock->flags & TYPE_FLAG_VOLATILE)) continue;
 148         return type;  /* it matched */
 149     }
 150     return NULL;
 151 }
 152
 153
 154 /* copy the exception object where the catch block wants it */
 155 static void copy_exception( void *object, cxx_exception_frame *frame,
 156                             catchblock_info *catchblock, const cxx_type_info *type )
 157 {
 158     void **dest_ptr;
 159
 160     if (!catchblock->type_info || !catchblock->type_info->mangled[0]) return;
 161     if (!catchblock->offset) return;
 162     dest_ptr = (void **)((char *)&frame->ebp + catchblock->offset);
 163
 164     if (catchblock->flags & TYPE_FLAG_REFERENCE)
 165     {
 166         *dest_ptr = get_this_pointer( &type->offsets, object );
 167     }
 168     else if (type->flags & CLASS_IS_SIMPLE_TYPE)
 169     {
 170         memmove( dest_ptr, object, type->size );
 171         /* if it is a pointer, adjust it */
 172         if (type->size == sizeof(void *)) *dest_ptr = get_this_pointer( &type->offsets, *dest_ptr );
 173     }
 174     else  /* copy the object */
 175     {
 176         if (type->copy_ctor)
 177             call_copy_ctor( type->copy_ctor, dest_ptr, get_this_pointer(&type->offsets,object),
 178                             (type->flags & CLASS_HAS_VIRTUAL_BASE_CLASS) );
 179         else
 180             memmove( dest_ptr, get_this_pointer(&type->offsets,object), type->size );
 181     }
 182 }
 183
 184 /* unwind the local function up to a given trylevel */
 185 static void cxx_local_unwind( cxx_exception_frame* frame, cxx_function_descr *descr, int last_level)
 186 {
 187     void (*handler)();
 188     int trylevel = frame->trylevel;
 189
 190     while (trylevel != last_level)
 191     {
 192         if (trylevel < 0 || trylevel >= descr->unwind_count)
 193         {
 194             ERR( "invalid trylevel %d\n", trylevel );
 195             MSVCRT_terminate();
 196         }
 197         handler = descr->unwind_table[trylevel].handler;
 198         if (handler)
 199         {
 200             TRACE( "calling unwind handler %p trylevel %d last %d ebp %p\n",
 201                    handler, trylevel, last_level, &frame->ebp );
 202             call_ebp_func( handler, &frame->ebp );
 203         }
 204         trylevel = descr->unwind_table[trylevel].prev;
 205     }
 206     frame->trylevel = last_level;
 207 }
 208
 209 /* exception frame for nested exceptions in catch block */
 210 struct catch_func_nested_frame
 211 {
 212     EXCEPTION_REGISTRATION_RECORD frame;     /* standard exception frame */
 213     EXCEPTION_RECORD             *prev_rec;  /* previous record to restore in thread data */
 214     cxx_exception_frame          *cxx_frame; /* frame of parent exception */
 215     cxx_function_descr           *descr;     /* descriptor of parent exception */
 216     int                           trylevel;  /* current try level */
 217 };
 218
 219 /* handler for exceptions happening while calling a catch function */
 220 static DWORD catch_function_nested_handler( EXCEPTION_RECORD *rec, EXCEPTION_REGISTRATION_RECORD *frame,
 221                                             CONTEXT *context, EXCEPTION_REGISTRATION_RECORD **dispatcher )
 222 {
 223     struct catch_func_nested_frame *nested_frame = (struct catch_func_nested_frame *)frame;
 224
 225     if (rec->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND))
 226     {
 227         msvcrt_get_thread_data()->exc_record = nested_frame->prev_rec;
 228         return ExceptionContinueSearch;
 229     }
 230     else
 231     {
 232         TRACE( "got nested exception in catch function\n" );
 233         return cxx_frame_handler( rec, nested_frame->cxx_frame, context,
 234                                   NULL, nested_frame->descr, &nested_frame->frame,
 235                                   nested_frame->trylevel, context );
 236     }
 237 }
 238
 239 /* find and call the appropriate catch block for an exception */
 240 /* returns the address to continue execution to after the catch block was called */
 241 inline static void *call_catch_block( PEXCEPTION_RECORD rec, cxx_exception_frame *frame,
 242                                       cxx_function_descr *descr, int nested_trylevel,
 243                                       cxx_exception_type *info )
 244 {
 245     UINT i;
 246     int j;
 247     void *addr, *object = (void *)rec->ExceptionInformation[1];
 248     struct catch_func_nested_frame nested_frame;
 249     int trylevel = frame->trylevel;
 250     thread_data_t *thread_data = msvcrt_get_thread_data();
 251
 252     for (i = 0; i < descr->tryblock_count; i++)
 253     {
 254         tryblock_info *tryblock = &descr->tryblock[i];
 255
 256         if (trylevel < tryblock->start_level) continue;
 257         if (trylevel > tryblock->end_level) continue;
 258
 259         /* got a try block */
 260         for (j = 0; j < tryblock->catchblock_count; j++)
 261         {
 262             catchblock_info *catchblock = &tryblock->catchblock[j];
 263             const cxx_type_info *type = find_caught_type( info, catchblock );
 264             if (!type) continue;
 265
 266             TRACE( "matched type %p in tryblock %d catchblock %d\n", type, i, j );
 267
 268             /* copy the exception to its destination on the stack */
 269             copy_exception( object, frame, catchblock, type );
 270
 271             /* unwind the stack */
 272             RtlUnwind( frame, 0, rec, 0 );
 273             cxx_local_unwind( frame, descr, tryblock->start_level );
 274             frame->trylevel = tryblock->end_level + 1;
 275
 276             /* call the catch block */
 277             TRACE( "calling catch block %p for type %p addr %p ebp %p\n",
 278                    catchblock, type, catchblock->handler, &frame->ebp );
 279
 280             /* setup an exception block for nested exceptions */
 281
 282             nested_frame.frame.Handler = catch_function_nested_handler;
 283             nested_frame.prev_rec  = thread_data->exc_record;
 284             nested_frame.cxx_frame = frame;
 285             nested_frame.descr     = descr;
 286             nested_frame.trylevel  = nested_trylevel + 1;
 287
 288             __wine_push_frame( &nested_frame.frame );
 289             thread_data->exc_record = rec;
 290             addr = call_ebp_func( catchblock->handler, &frame->ebp );
 291             thread_data->exc_record = nested_frame.prev_rec;
 292             __wine_pop_frame( &nested_frame.frame );
 293
 294             if (info->destructor) call_dtor( info->destructor, object );
 295             TRACE( "done, continuing at %p\n", addr );
 296             return addr;
 297         }
 298     }
 299     return NULL;
 300 }
 301
 302
 303 /*********************************************************************
 304  *              cxx_frame_handler
 305  *
 306  * Implementation of __CxxFrameHandler.
 307  */
 308 static DWORD cxx_frame_handler( PEXCEPTION_RECORD rec, cxx_exception_frame* frame,
 309                                 PCONTEXT exc_context, EXCEPTION_REGISTRATION_RECORD** dispatch,
 310                                 cxx_function_descr *descr, EXCEPTION_REGISTRATION_RECORD* nested_frame,
 311                                 int nested_trylevel, CONTEXT86 *context )
 312 {
 313     cxx_exception_type *exc_type;
 314     void *next_ip;
 315
 316     if (descr->magic != CXX_FRAME_MAGIC)
 317     {
 318         ERR( "invalid frame magic %x\n", descr->magic );
 319         return ExceptionContinueSearch;
 320     }
 321     if (rec->ExceptionFlags & (EH_UNWINDING|EH_EXIT_UNWIND))
 322     {
 323         if (descr->unwind_count && !nested_trylevel) cxx_local_unwind( frame, descr, -1 );
 324         return ExceptionContinueSearch;
 325     }
 326     if (!descr->tryblock_count) return ExceptionContinueSearch;
 327
 328     exc_type = (cxx_exception_type *)rec->ExceptionInformation[2];
 329     if (rec->ExceptionCode == CXX_EXCEPTION &&
 330         rec->ExceptionInformation[0] > CXX_FRAME_MAGIC &&
 331         exc_type->custom_handler)
 332     {
 333         return exc_type->custom_handler( rec, frame, exc_context, dispatch,
 334                                          descr, nested_trylevel, nested_frame, 0 );
 335     }
 336
 337     if (!exc_type)  /* nested exception, fetch info from original exception */
 338     {
 339         rec = msvcrt_get_thread_data()->exc_record;
 340         exc_type = (cxx_exception_type *)rec->ExceptionInformation[2];
 341     }
 342
 343     if (TRACE_ON(seh))
 344     {
 345         TRACE("handling C++ exception rec %p frame %p trylevel %d descr %p nested_frame %p\n",
 346               rec, frame, frame->trylevel, descr, nested_frame );
 347         dump_exception_type( exc_type );
 348         dump_function_descr( descr, exc_type );
 349     }
 350
 351     next_ip = call_catch_block( rec, frame, descr, frame->trylevel, exc_type );
 352
 353     if (!next_ip) return ExceptionContinueSearch;
 354     rec->ExceptionFlags &= ~EH_NONCONTINUABLE;
 355     context->Eip = (DWORD)next_ip;
 356     context->Ebp = (DWORD)&frame->ebp;
 357     context->Esp = ((DWORD*)frame)[-1];
 358     return ExceptionContinueExecution;
 359 }
 360
 361
 362 /*********************************************************************
 363  *              __CxxFrameHandler (MSVCRT.@)
 364  */
 365 void WINAPI __regs___CxxFrameHandler( PEXCEPTION_RECORD rec, EXCEPTION_REGISTRATION_RECORD* frame,
 366                                       PCONTEXT exc_context, EXCEPTION_REGISTRATION_RECORD** dispatch,
 367                                       CONTEXT86 *context )
 368 {
 369     cxx_function_descr *descr = (cxx_function_descr *)context->Eax;
 370     context->Eax = cxx_frame_handler( rec, (cxx_exception_frame *)frame,
 371                                       exc_context, dispatch, descr, NULL, 0, context );
 372 }
 373 DEFINE_REGS_ENTRYPOINT( __CxxFrameHandler, 16, 0 );
 374
 375 #endif  /* __i386__ */
 376
 377 /*********************************************************************
 378  *              _CxxThrowException (MSVCRT.@)
 379  */
 380 void _CxxThrowException( exception *object, const cxx_exception_type *type )
 381 {
 382     ULONG_PTR args[3];
 383
 384     args[0] = CXX_FRAME_MAGIC;
 385     args[1] = (ULONG_PTR)object;
 386     args[2] = (ULONG_PTR)type;
 387     RaiseException( CXX_EXCEPTION, EH_NONCONTINUABLE, 3, args );
 388 }
 389
 390 /*********************************************************************
 391  *              __CxxDetectRethrow (MSVCRT.@)
 392  */
 393 BOOL __CxxDetectRethrow(PEXCEPTION_POINTERS ptrs)
 394 {
 395   PEXCEPTION_RECORD rec;
 396
 397   if (!ptrs)
 398     return FALSE;
 399
 400   rec = ptrs->ExceptionRecord;
 401
 402   if (rec->ExceptionCode == CXX_EXCEPTION &&
 403       rec->NumberParameters == 3 &&
 404       rec->ExceptionInformation[0] == CXX_FRAME_MAGIC &&
 405       rec->ExceptionInformation[2])
 406   {
 407     ptrs->ExceptionRecord = msvcrt_get_thread_data()->exc_record;
 408     return TRUE;
 409   }
 410   return (msvcrt_get_thread_data()->exc_record == rec);
 411 }
 412
 413 /*********************************************************************
 414  *              __CxxQueryExceptionSize (MSVCRT.@)
 415  */
 416 unsigned int __CxxQueryExceptionSize(void)
 417 {
 418   return sizeof(cxx_exception_type);
 419 }