wine/dlls/msvcrt/cppexcept.c

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/*
* msvcrt C++ exception handling
*
* Copyright 2002 Alexandre Julliard
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* NOTES
* A good reference is the article "How a C++ compiler implements
* exception handling" by Vishal Kochhar, available on
* www.thecodeproject.com.
*/
#include "config.h"
#include "wine/port.h"
#include <stdarg.h>
#include "windef.h"
#include "winbase.h"
#include "winreg.h"
#include "winternl.h"
#include "msvcrt.h"
#include "wine/exception.h"
#include "excpt.h"
#include "wine/debug.h"
#include "cppexcept.h"
WINE_DEFAULT_DEBUG_CHANNEL(seh);
#ifdef __i386__ /* CxxFrameHandler is not supported on non-i386 */
static DWORD cxx_frame_handler( PEXCEPTION_RECORD rec, cxx_exception_frame* frame,
PCONTEXT exc_context, EXCEPTION_REGISTRATION_RECORD** dispatch,
cxx_function_descr *descr, EXCEPTION_REGISTRATION_RECORD* nested_frame,
int nested_trylevel, CONTEXT86 *context );
/* call a function with a given ebp */
inline static void *call_ebp_func( void *func, void *ebp )
{
void *ret;
__asm__ __volatile__ ("pushl %%ebp; movl %2,%%ebp; call *%%eax; popl %%ebp" \
: "=a" (ret) : "0" (func), "g" (ebp) : "ecx", "edx", "memory" );
return ret;
}
/* call a copy constructor */
inline static void call_copy_ctor( void *func, void *this, void *src, int has_vbase )
{
TRACE( "calling copy ctor %p object %p src %p\n", func, this, src );
if (has_vbase)
/* in that case copy ctor takes an extra bool indicating whether to copy the base class */
__asm__ __volatile__("pushl $1; pushl %2; call *%0"
: : "r" (func), "c" (this), "g" (src) : "eax", "edx", "memory" );
else
__asm__ __volatile__("pushl %2; call *%0"
: : "r" (func), "c" (this), "g" (src) : "eax", "edx", "memory" );
}
/* call the destructor of the exception object */
inline static void call_dtor( void *func, void *object )
{
__asm__ __volatile__("call *%0" : : "r" (func), "c" (object) : "eax", "edx", "memory" );
}
static inline void dump_type( const cxx_type_info *type )
{
DPRINTF( "flags %x type %p %s offsets %d,%d,%d size %d copy ctor %p\n",
type->flags, type->type_info, dbgstr_type_info(type->type_info),
type->offsets.this_offset, type->offsets.vbase_descr, type->offsets.vbase_offset,
type->size, type->copy_ctor );
}
static void dump_exception_type( const cxx_exception_type *type )
{
UINT i;
DPRINTF( "exception type:\n" );
DPRINTF( "flags %x destr %p handler %p type info %p\n",
type->flags, type->destructor, type->custom_handler, type->type_info_table );
for (i = 0; i < type->type_info_table->count; i++)
{
DPRINTF( " %d: ", i );
dump_type( type->type_info_table->info[i] );
}
}
static void dump_function_descr( const cxx_function_descr *descr, const cxx_exception_type *info )
{
UINT i;
int j;
DPRINTF( "function descr:\n" );
DPRINTF( "magic %x\n", descr->magic );
DPRINTF( "unwind table: %p %d\n", descr->unwind_table, descr->unwind_count );
for (i = 0; i < descr->unwind_count; i++)
{
DPRINTF( " %d: prev %d func %p\n", i,
descr->unwind_table[i].prev, descr->unwind_table[i].handler );
}
DPRINTF( "try table: %p %d\n", descr->tryblock, descr->tryblock_count );
for (i = 0; i < descr->tryblock_count; i++)
{
DPRINTF( " %d: start %d end %d catchlevel %d catch %p %d\n", i,
descr->tryblock[i].start_level, descr->tryblock[i].end_level,
descr->tryblock[i].catch_level, descr->tryblock[i].catchblock,
descr->tryblock[i].catchblock_count );
for (j = 0; j < descr->tryblock[i].catchblock_count; j++)
{
catchblock_info *ptr = &descr->tryblock[i].catchblock[j];
DPRINTF( " %d: flags %x offset %d handler %p type %p %s\n",
j, ptr->flags, ptr->offset, ptr->handler,
ptr->type_info, dbgstr_type_info( ptr->type_info ) );
}
}
}
/* check if the exception type is caught by a given catch block, and return the type that matched */
static const cxx_type_info *find_caught_type( cxx_exception_type *exc_type, catchblock_info *catchblock )
{
UINT i;
for (i = 0; i < exc_type->type_info_table->count; i++)
{
const cxx_type_info *type = exc_type->type_info_table->info[i];
if (!catchblock->type_info) return type; /* catch(...) matches any type */
if (catchblock->type_info != type->type_info)
{
if (strcmp( catchblock->type_info->mangled, type->type_info->mangled )) continue;
}
/* type is the same, now check the flags */
if ((exc_type->flags & TYPE_FLAG_CONST) &&
!(catchblock->flags & TYPE_FLAG_CONST)) continue;
if ((exc_type->flags & TYPE_FLAG_VOLATILE) &&
!(catchblock->flags & TYPE_FLAG_VOLATILE)) continue;
return type; /* it matched */
}
return NULL;
}
/* copy the exception object where the catch block wants it */
static void copy_exception( void *object, cxx_exception_frame *frame,
catchblock_info *catchblock, const cxx_type_info *type )
{
void **dest_ptr;
if (!catchblock->type_info || !catchblock->type_info->mangled[0]) return;
if (!catchblock->offset) return;
dest_ptr = (void **)((char *)&frame->ebp + catchblock->offset);
if (catchblock->flags & TYPE_FLAG_REFERENCE)
{
*dest_ptr = get_this_pointer( &type->offsets, object );
}
else if (type->flags & CLASS_IS_SIMPLE_TYPE)
{
memmove( dest_ptr, object, type->size );
/* if it is a pointer, adjust it */
if (type->size == sizeof(void *)) *dest_ptr = get_this_pointer( &type->offsets, *dest_ptr );
}
else /* copy the object */
{
if (type->copy_ctor)
call_copy_ctor( type->copy_ctor, dest_ptr, get_this_pointer(&type->offsets,object),
(type->flags & CLASS_HAS_VIRTUAL_BASE_CLASS) );
else
memmove( dest_ptr, get_this_pointer(&type->offsets,object), type->size );
}
}
/* unwind the local function up to a given trylevel */
static void cxx_local_unwind( cxx_exception_frame* frame, cxx_function_descr *descr, int last_level)
{
void (*handler)();
int trylevel = frame->trylevel;
while (trylevel != last_level)
{
if (trylevel < 0 || trylevel >= descr->unwind_count)
{
ERR( "invalid trylevel %d\n", trylevel );
MSVCRT_terminate();
}
handler = descr->unwind_table[trylevel].handler;
if (handler)
{
TRACE( "calling unwind handler %p trylevel %d last %d ebp %p\n",
handler, trylevel, last_level, &frame->ebp );
call_ebp_func( handler, &frame->ebp );
}
trylevel = descr->unwind_table[trylevel].prev;
}
frame->trylevel = last_level;
}
/* exception frame for nested exceptions in catch block */
struct catch_func_nested_frame
{
EXCEPTION_REGISTRATION_RECORD frame; /* standard exception frame */
EXCEPTION_RECORD *prev_rec; /* previous record to restore in thread data */
cxx_exception_frame *cxx_frame; /* frame of parent exception */
cxx_function_descr *descr; /* descriptor of parent exception */
int trylevel; /* current try level */
};
/* handler for exceptions happening while calling a catch function */
static DWORD catch_function_nested_handler( EXCEPTION_RECORD *rec, EXCEPTION_REGISTRATION_RECORD *frame,
CONTEXT *context, EXCEPTION_REGISTRATION_RECORD **dispatcher )
{
struct catch_func_nested_frame *nested_frame = (struct catch_func_nested_frame *)frame;
if (rec->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND))
{
msvcrt_get_thread_data()->exc_record = nested_frame->prev_rec;
return ExceptionContinueSearch;
}
else
{
TRACE( "got nested exception in catch function\n" );
return cxx_frame_handler( rec, nested_frame->cxx_frame, context,
NULL, nested_frame->descr, &nested_frame->frame,
nested_frame->trylevel, context );
}
}
/* find and call the appropriate catch block for an exception */
/* returns the address to continue execution to after the catch block was called */
inline static void *call_catch_block( PEXCEPTION_RECORD rec, cxx_exception_frame *frame,
cxx_function_descr *descr, int nested_trylevel,
cxx_exception_type *info )
{
UINT i;
int j;
void *addr, *object = (void *)rec->ExceptionInformation[1];
struct catch_func_nested_frame nested_frame;
int trylevel = frame->trylevel;
thread_data_t *thread_data = msvcrt_get_thread_data();
for (i = 0; i < descr->tryblock_count; i++)
{
tryblock_info *tryblock = &descr->tryblock[i];
if (trylevel < tryblock->start_level) continue;
if (trylevel > tryblock->end_level) continue;
/* got a try block */
for (j = 0; j < tryblock->catchblock_count; j++)
{
catchblock_info *catchblock = &tryblock->catchblock[j];
const cxx_type_info *type = find_caught_type( info, catchblock );
if (!type) continue;
TRACE( "matched type %p in tryblock %d catchblock %d\n", type, i, j );
/* copy the exception to its destination on the stack */
copy_exception( object, frame, catchblock, type );
/* unwind the stack */
RtlUnwind( frame, 0, rec, 0 );
cxx_local_unwind( frame, descr, tryblock->start_level );
frame->trylevel = tryblock->end_level + 1;
/* call the catch block */
TRACE( "calling catch block %p for type %p addr %p ebp %p\n",
catchblock, type, catchblock->handler, &frame->ebp );
/* setup an exception block for nested exceptions */
nested_frame.frame.Handler = catch_function_nested_handler;
nested_frame.prev_rec = thread_data->exc_record;
nested_frame.cxx_frame = frame;
nested_frame.descr = descr;
nested_frame.trylevel = nested_trylevel + 1;
__wine_push_frame( &nested_frame.frame );
thread_data->exc_record = rec;
addr = call_ebp_func( catchblock->handler, &frame->ebp );
thread_data->exc_record = nested_frame.prev_rec;
__wine_pop_frame( &nested_frame.frame );
if (info->destructor) call_dtor( info->destructor, object );
TRACE( "done, continuing at %p\n", addr );
return addr;
}
}
return NULL;
}
/*********************************************************************
* cxx_frame_handler
*
* Implementation of __CxxFrameHandler.
*/
static DWORD cxx_frame_handler( PEXCEPTION_RECORD rec, cxx_exception_frame* frame,
PCONTEXT exc_context, EXCEPTION_REGISTRATION_RECORD** dispatch,
cxx_function_descr *descr, EXCEPTION_REGISTRATION_RECORD* nested_frame,
int nested_trylevel, CONTEXT86 *context )
{
cxx_exception_type *exc_type;
void *next_ip;
if (descr->magic != CXX_FRAME_MAGIC)
{
ERR( "invalid frame magic %x\n", descr->magic );
return ExceptionContinueSearch;
}
if (rec->ExceptionFlags & (EH_UNWINDING|EH_EXIT_UNWIND))
{
if (descr->unwind_count && !nested_trylevel) cxx_local_unwind( frame, descr, -1 );
return ExceptionContinueSearch;
}
if (!descr->tryblock_count) return ExceptionContinueSearch;
exc_type = (cxx_exception_type *)rec->ExceptionInformation[2];
if (rec->ExceptionCode == CXX_EXCEPTION &&
rec->ExceptionInformation[0] > CXX_FRAME_MAGIC &&
exc_type->custom_handler)
{
return exc_type->custom_handler( rec, frame, exc_context, dispatch,
descr, nested_trylevel, nested_frame, 0 );
}
if (!exc_type) /* nested exception, fetch info from original exception */
{
rec = msvcrt_get_thread_data()->exc_record;
exc_type = (cxx_exception_type *)rec->ExceptionInformation[2];
}
if (TRACE_ON(seh))
{
TRACE("handling C++ exception rec %p frame %p trylevel %d descr %p nested_frame %p\n",
rec, frame, frame->trylevel, descr, nested_frame );
dump_exception_type( exc_type );
dump_function_descr( descr, exc_type );
}
next_ip = call_catch_block( rec, frame, descr, frame->trylevel, exc_type );
if (!next_ip) return ExceptionContinueSearch;
rec->ExceptionFlags &= ~EH_NONCONTINUABLE;
context->Eip = (DWORD)next_ip;
context->Ebp = (DWORD)&frame->ebp;
context->Esp = ((DWORD*)frame)[-1];
return ExceptionContinueExecution;
}
/*********************************************************************
* __CxxFrameHandler (MSVCRT.@)
*/
void MSVCRT__CxxFrameHandler( PEXCEPTION_RECORD rec, EXCEPTION_REGISTRATION_RECORD* frame,
PCONTEXT exc_context, EXCEPTION_REGISTRATION_RECORD** dispatch,
CONTEXT86 *context )
{
cxx_function_descr *descr = (cxx_function_descr *)context->Eax;
context->Eax = cxx_frame_handler( rec, (cxx_exception_frame *)frame,
exc_context, dispatch, descr, NULL, 0, context );
}
DEFINE_REGS_ENTRYPOINT( __CxxFrameHandler, MSVCRT__CxxFrameHandler, 16, 0 );
#endif /* __i386__ */
/*********************************************************************
* _CxxThrowException (MSVCRT.@)
*/
void _CxxThrowException( void *object, const cxx_exception_type *type )
{
DWORD args[3];
args[0] = CXX_FRAME_MAGIC;
args[1] = (DWORD)object;
args[2] = (DWORD)type;
RaiseException( CXX_EXCEPTION, EH_NONCONTINUABLE, 3, args );
}
/*********************************************************************
* __CxxDetectRethrow (MSVCRT.@)
*/
BOOL __CxxDetectRethrow(PEXCEPTION_POINTERS ptrs)
{
PEXCEPTION_RECORD rec;
if (!ptrs)
return FALSE;
rec = ptrs->ExceptionRecord;
if (rec->ExceptionCode == CXX_EXCEPTION &&
rec->NumberParameters == 3 &&
rec->ExceptionInformation[0] == CXX_FRAME_MAGIC &&
rec->ExceptionInformation[2])
{
ptrs->ExceptionRecord = msvcrt_get_thread_data()->exc_record;
return TRUE;
}
return (msvcrt_get_thread_data()->exc_record == rec);
}
/*********************************************************************
* __CxxQueryExceptionSize (MSVCRT.@)
*/
unsigned int __CxxQueryExceptionSize(void)
{
return sizeof(cxx_exception_type);
}