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     DPRINTF( "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     DPRINTF( "exception type:\n" );
  92     DPRINTF( "flags %x destr %p handler %p type info %p\n",
  93              type->flags, type->destructor, type->custom_handler, type->type_info_table );
  94     for (i = 0; i < type->type_info_table->count; i++)
  95     {
  96         DPRINTF( "    %d: ", i );
  97         dump_type( type->type_info_table->info[i] );
  98     }
  99 }
 100
 101 static void dump_function_descr( const cxx_function_descr *descr, const cxx_exception_type *info )
 102 {
 103     UINT i;
 104     int j;
 105
 106     DPRINTF( "function descr:\n" );
 107     DPRINTF( "magic %x\n", descr->magic );
 108     DPRINTF( "unwind table: %p %d\n", descr->unwind_table, descr->unwind_count );
 109     for (i = 0; i < descr->unwind_count; i++)
 110     {
 111         DPRINTF( "    %d: prev %d func %p\n", i,
 112                  descr->unwind_table[i].prev, descr->unwind_table[i].handler );
 113     }
 114     DPRINTF( "try table: %p %d\n", descr->tryblock, descr->tryblock_count );
 115     for (i = 0; i < descr->tryblock_count; i++)
 116     {
 117         DPRINTF( "    %d: start %d end %d catchlevel %d catch %p %d\n", i,
 118                  descr->tryblock[i].start_level, descr->tryblock[i].end_level,
 119                  descr->tryblock[i].catch_level, descr->tryblock[i].catchblock,
 120                  descr->tryblock[i].catchblock_count );
 121         for (j = 0; j < descr->tryblock[i].catchblock_count; j++)
 122         {
 123             catchblock_info *ptr = &descr->tryblock[i].catchblock[j];
 124             DPRINTF( "        %d: flags %x offset %d handler %p type %p %s\n",
 125                      j, ptr->flags, ptr->offset, ptr->handler,
 126                      ptr->type_info, dbgstr_type_info( ptr->type_info ) );
 127         }
 128     }
 129 }
 130
 131 /* check if the exception type is caught by a given catch block, and return the type that matched */
 132 static const cxx_type_info *find_caught_type( cxx_exception_type *exc_type, catchblock_info *catchblock )
 133 {
 134     UINT i;
 135
 136     for (i = 0; i < exc_type->type_info_table->count; i++)
 137     {
 138         const cxx_type_info *type = exc_type->type_info_table->info[i];
 139
 140         if (!catchblock->type_info) return type;   /* catch(...) matches any type */
 141         if (catchblock->type_info != type->type_info)
 142         {
 143             if (strcmp( catchblock->type_info->mangled, type->type_info->mangled )) continue;
 144         }
 145         /* type is the same, now check the flags */
 146         if ((exc_type->flags & TYPE_FLAG_CONST) &&
 147             !(catchblock->flags & TYPE_FLAG_CONST)) continue;
 148         if ((exc_type->flags & TYPE_FLAG_VOLATILE) &&
 149             !(catchblock->flags & TYPE_FLAG_VOLATILE)) continue;
 150         return type;  /* it matched */
 151     }
 152     return NULL;
 153 }
 154
 155
 156 /* copy the exception object where the catch block wants it */
 157 static void copy_exception( void *object, cxx_exception_frame *frame,
 158                             catchblock_info *catchblock, const cxx_type_info *type )
 159 {
 160     void **dest_ptr;
 161
 162     if (!catchblock->type_info || !catchblock->type_info->mangled[0]) return;
 163     if (!catchblock->offset) return;
 164     dest_ptr = (void **)((char *)&frame->ebp + catchblock->offset);
 165
 166     if (catchblock->flags & TYPE_FLAG_REFERENCE)
 167     {
 168         *dest_ptr = get_this_pointer( &type->offsets, object );
 169     }
 170     else if (type->flags & CLASS_IS_SIMPLE_TYPE)
 171     {
 172         memmove( dest_ptr, object, type->size );
 173         /* if it is a pointer, adjust it */
 174         if (type->size == sizeof(void *)) *dest_ptr = get_this_pointer( &type->offsets, *dest_ptr );
 175     }
 176     else  /* copy the object */
 177     {
 178         if (type->copy_ctor)
 179             call_copy_ctor( type->copy_ctor, dest_ptr, get_this_pointer(&type->offsets,object),
 180                             (type->flags & CLASS_HAS_VIRTUAL_BASE_CLASS) );
 181         else
 182             memmove( dest_ptr, get_this_pointer(&type->offsets,object), type->size );
 183     }
 184 }
 185
 186 /* unwind the local function up to a given trylevel */
 187 static void cxx_local_unwind( cxx_exception_frame* frame, cxx_function_descr *descr, int last_level)
 188 {
 189     void (*handler)();
 190     int trylevel = frame->trylevel;
 191
 192     while (trylevel != last_level)
 193     {
 194         if (trylevel < 0 || trylevel >= descr->unwind_count)
 195         {
 196             ERR( "invalid trylevel %d\n", trylevel );
 197             MSVCRT_terminate();
 198         }
 199         handler = descr->unwind_table[trylevel].handler;
 200         if (handler)
 201         {
 202             TRACE( "calling unwind handler %p trylevel %d last %d ebp %p\n",
 203                    handler, trylevel, last_level, &frame->ebp );
 204             call_ebp_func( handler, &frame->ebp );
 205         }
 206         trylevel = descr->unwind_table[trylevel].prev;
 207     }
 208     frame->trylevel = last_level;
 209 }
 210
 211 /* exception frame for nested exceptions in catch block */
 212 struct catch_func_nested_frame
 213 {
 214     EXCEPTION_REGISTRATION_RECORD frame;     /* standard exception frame */
 215     EXCEPTION_RECORD             *prev_rec;  /* previous record to restore in thread data */
 216     cxx_exception_frame          *cxx_frame; /* frame of parent exception */
 217     cxx_function_descr           *descr;     /* descriptor of parent exception */
 218     int                           trylevel;  /* current try level */
 219 };
 220
 221 /* handler for exceptions happening while calling a catch function */
 222 static DWORD catch_function_nested_handler( EXCEPTION_RECORD *rec, EXCEPTION_REGISTRATION_RECORD *frame,
 223                                             CONTEXT *context, EXCEPTION_REGISTRATION_RECORD **dispatcher )
 224 {
 225     struct catch_func_nested_frame *nested_frame = (struct catch_func_nested_frame *)frame;
 226
 227     if (rec->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND))
 228     {
 229         msvcrt_get_thread_data()->exc_record = nested_frame->prev_rec;
 230         return ExceptionContinueSearch;
 231     }
 232     else
 233     {
 234         TRACE( "got nested exception in catch function\n" );
 235         return cxx_frame_handler( rec, nested_frame->cxx_frame, context,
 236                                   NULL, nested_frame->descr, &nested_frame->frame,
 237                                   nested_frame->trylevel, context );
 238     }
 239 }
 240
 241 /* find and call the appropriate catch block for an exception */
 242 /* returns the address to continue execution to after the catch block was called */
 243 inline static void *call_catch_block( PEXCEPTION_RECORD rec, cxx_exception_frame *frame,
 244                                       cxx_function_descr *descr, int nested_trylevel,
 245                                       cxx_exception_type *info )
 246 {
 247     UINT i;
 248     int j;
 249     void *addr, *object = (void *)rec->ExceptionInformation[1];
 250     struct catch_func_nested_frame nested_frame;
 251     int trylevel = frame->trylevel;
 252     thread_data_t *thread_data = msvcrt_get_thread_data();
 253
 254     for (i = 0; i < descr->tryblock_count; i++)
 255     {
 256         tryblock_info *tryblock = &descr->tryblock[i];
 257
 258         if (trylevel < tryblock->start_level) continue;
 259         if (trylevel > tryblock->end_level) continue;
 260
 261         /* got a try block */
 262         for (j = 0; j < tryblock->catchblock_count; j++)
 263         {
 264             catchblock_info *catchblock = &tryblock->catchblock[j];
 265             const cxx_type_info *type = find_caught_type( info, catchblock );
 266             if (!type) continue;
 267
 268             TRACE( "matched type %p in tryblock %d catchblock %d\n", type, i, j );
 269
 270             /* copy the exception to its destination on the stack */
 271             copy_exception( object, frame, catchblock, type );
 272
 273             /* unwind the stack */
 274             RtlUnwind( frame, 0, rec, 0 );
 275             cxx_local_unwind( frame, descr, tryblock->start_level );
 276             frame->trylevel = tryblock->end_level + 1;
 277
 278             /* call the catch block */
 279             TRACE( "calling catch block %p for type %p addr %p ebp %p\n",
 280                    catchblock, type, catchblock->handler, &frame->ebp );
 281
 282             /* setup an exception block for nested exceptions */
 283
 284             nested_frame.frame.Handler = catch_function_nested_handler;
 285             nested_frame.prev_rec  = thread_data->exc_record;
 286             nested_frame.cxx_frame = frame;
 287             nested_frame.descr     = descr;
 288             nested_frame.trylevel  = nested_trylevel + 1;
 289
 290             __wine_push_frame( &nested_frame.frame );
 291             thread_data->exc_record = rec;
 292             addr = call_ebp_func( catchblock->handler, &frame->ebp );
 293             thread_data->exc_record = nested_frame.prev_rec;
 294             __wine_pop_frame( &nested_frame.frame );
 295
 296             if (info->destructor) call_dtor( info->destructor, object );
 297             TRACE( "done, continuing at %p\n", addr );
 298             return addr;
 299         }
 300     }
 301     return NULL;
 302 }
 303
 304
 305 /*********************************************************************
 306  *              cxx_frame_handler
 307  *
 308  * Implementation of __CxxFrameHandler.
 309  */
 310 static DWORD cxx_frame_handler( PEXCEPTION_RECORD rec, cxx_exception_frame* frame,
 311                                 PCONTEXT exc_context, EXCEPTION_REGISTRATION_RECORD** dispatch,
 312                                 cxx_function_descr *descr, EXCEPTION_REGISTRATION_RECORD* nested_frame,
 313                                 int nested_trylevel, CONTEXT86 *context )
 314 {
 315     cxx_exception_type *exc_type;
 316     void *next_ip;
 317
 318     if (descr->magic != CXX_FRAME_MAGIC)
 319     {
 320         ERR( "invalid frame magic %x\n", descr->magic );
 321         return ExceptionContinueSearch;
 322     }
 323     if (rec->ExceptionFlags & (EH_UNWINDING|EH_EXIT_UNWIND))
 324     {
 325         if (descr->unwind_count && !nested_trylevel) cxx_local_unwind( frame, descr, -1 );
 326         return ExceptionContinueSearch;
 327     }
 328     if (!descr->tryblock_count) return ExceptionContinueSearch;
 329
 330     exc_type = (cxx_exception_type *)rec->ExceptionInformation[2];
 331     if (rec->ExceptionCode == CXX_EXCEPTION &&
 332         rec->ExceptionInformation[0] > CXX_FRAME_MAGIC &&
 333         exc_type->custom_handler)
 334     {
 335         return exc_type->custom_handler( rec, frame, exc_context, dispatch,
 336                                          descr, nested_trylevel, nested_frame, 0 );
 337     }
 338
 339     if (!exc_type)  /* nested exception, fetch info from original exception */
 340     {
 341         rec = msvcrt_get_thread_data()->exc_record;
 342         exc_type = (cxx_exception_type *)rec->ExceptionInformation[2];
 343     }
 344
 345     if (TRACE_ON(seh))
 346     {
 347         TRACE("handling C++ exception rec %p frame %p trylevel %d descr %p nested_frame %p\n",
 348               rec, frame, frame->trylevel, descr, nested_frame );
 349         dump_exception_type( exc_type );
 350         dump_function_descr( descr, exc_type );
 351     }
 352
 353     next_ip = call_catch_block( rec, frame, descr, frame->trylevel, exc_type );
 354
 355     if (!next_ip) return ExceptionContinueSearch;
 356     rec->ExceptionFlags &= ~EH_NONCONTINUABLE;
 357     context->Eip = (DWORD)next_ip;
 358     context->Ebp = (DWORD)&frame->ebp;
 359     context->Esp = ((DWORD*)frame)[-1];
 360     return ExceptionContinueExecution;
 361 }
 362
 363
 364 /*********************************************************************
 365  *              __CxxFrameHandler (MSVCRT.@)
 366  */
 367 void WINAPI __regs___CxxFrameHandler( PEXCEPTION_RECORD rec, EXCEPTION_REGISTRATION_RECORD* frame,
 368                                       PCONTEXT exc_context, EXCEPTION_REGISTRATION_RECORD** dispatch,
 369                                       CONTEXT86 *context )
 370 {
 371     cxx_function_descr *descr = (cxx_function_descr *)context->Eax;
 372     context->Eax = cxx_frame_handler( rec, (cxx_exception_frame *)frame,
 373                                       exc_context, dispatch, descr, NULL, 0, context );
 374 }
 375 DEFINE_REGS_ENTRYPOINT( __CxxFrameHandler, 16, 0 );
 376
 377 #endif  /* __i386__ */
 378
 379 /*********************************************************************
 380  *              _CxxThrowException (MSVCRT.@)
 381  */
 382 void _CxxThrowException( exception *object, const cxx_exception_type *type )
 383 {
 384     DWORD args[3];
 385
 386     args[0] = CXX_FRAME_MAGIC;
 387     args[1] = (DWORD)object;
 388     args[2] = (DWORD)type;
 389     RaiseException( CXX_EXCEPTION, EH_NONCONTINUABLE, 3, args );
 390 }
 391
 392 /*********************************************************************
 393  *              __CxxDetectRethrow (MSVCRT.@)
 394  */
 395 BOOL __CxxDetectRethrow(PEXCEPTION_POINTERS ptrs)
 396 {
 397   PEXCEPTION_RECORD rec;
 398
 399   if (!ptrs)
 400     return FALSE;
 401
 402   rec = ptrs->ExceptionRecord;
 403
 404   if (rec->ExceptionCode == CXX_EXCEPTION &&
 405       rec->NumberParameters == 3 &&
 406       rec->ExceptionInformation[0] == CXX_FRAME_MAGIC &&
 407       rec->ExceptionInformation[2])
 408   {
 409     ptrs->ExceptionRecord = msvcrt_get_thread_data()->exc_record;
 410     return TRUE;
 411   }
 412   return (msvcrt_get_thread_data()->exc_record == rec);
 413 }
 414
 415 /*********************************************************************
 416  *              __CxxQueryExceptionSize (MSVCRT.@)
 417  */
 418 unsigned int __CxxQueryExceptionSize(void)
 419 {
 420   return sizeof(cxx_exception_type);
 421 }