Sweden-Number/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 "winternl.h"
#include "msvcrt.h"
#include "wine/exception.h"
#include "msvcrt/excpt.h"
#include "wine/debug.h"
WINE_DEFAULT_DEBUG_CHANNEL(seh);
#define CXX_FRAME_MAGIC 0x19930520
#define CXX_EXCEPTION 0xe06d7363
typedef struct __type_info
{
void *vtable;
void *data;
char name[1];
} type_info;
/* the exception frame used by CxxFrameHandler */
typedef struct __cxx_exception_frame
{
EXCEPTION_FRAME *prev;
void (*handler)(PEXCEPTION_RECORD, PEXCEPTION_FRAME, PCONTEXT, PEXCEPTION_RECORD);
int trylevel;
DWORD ebp;
} cxx_exception_frame;
/* info about a single catch {} block */
typedef struct __catchblock_info
{
UINT flags; /* flags (see below) */
type_info *type_info; /* C++ type caught by this block */
int offset; /* stack offset to copy exception object to */
void (*handler)(); /* catch block handler code */
} catchblock_info;
#define TYPE_FLAG_CONST 1
#define TYPE_FLAG_VOLATILE 2
#define TYPE_FLAG_REFERENCE 8
/* info about a single try {} block */
typedef struct __tryblock_info
{
int start_level; /* start trylevel of that block */
int end_level; /* end trylevel of that block */
int catch_level; /* initial trylevel of the catch block */
int catchblock_count; /* count of catch blocks in array */
catchblock_info *catchblock; /* array of catch blocks */
} tryblock_info;
/* info about the unwind handler for a given trylevel */
typedef struct __unwind_info
{
int prev; /* prev trylevel unwind handler, to run after this one */
void (*handler)(); /* unwind handler */
} unwind_info;
/* descriptor of all try blocks of a given function */
typedef struct __cxx_function_descr
{
UINT magic; /* must be CXX_FRAME_MAGIC */
UINT unwind_count; /* number of unwind handlers */
unwind_info *unwind_table; /* array of unwind handlers */
UINT tryblock_count; /* number of try blocks */
tryblock_info *tryblock; /* array of try blocks */
UINT unknown[3];
} cxx_function_descr;
/* complete information about a C++ type */
typedef struct __cxx_type_info
{
UINT flags; /* flags (see CLASS_* flags below) */
type_info *type_info; /* C++ type info */
int this_offset; /* offset of base class this pointer from start of object */
int vbase_descr; /* offset of virtual base class descriptor */
int vbase_offset; /* offset of this pointer offset in virtual base class descriptor */
size_t size; /* object size */
void (*copy_ctor)(); /* copy constructor */
} cxx_type_info;
#define CLASS_IS_SIMPLE_TYPE 1
#define CLASS_HAS_VIRTUAL_BASE_CLASS 4
/* table of C++ types that apply for a given object */
typedef struct __cxx_type_info_table
{
UINT count; /* number of types */
cxx_type_info *info[1]; /* array of types */
} cxx_type_info_table;
typedef DWORD (*cxx_exc_custom_handler)( PEXCEPTION_RECORD, cxx_exception_frame*,
PCONTEXT, struct __EXCEPTION_FRAME**,
cxx_function_descr*, DWORD unknown1,
DWORD unknown2, DWORD unknown3 );
/* type information for an exception object */
typedef struct __cxx_exception_type
{
UINT flags; /* TYPE_FLAG flags */
void (*destructor)(); /* exception object destructor */
cxx_exc_custom_handler custom_handler; /* custom handler for this exception */
cxx_type_info_table *type_info_table; /* list of types for this exception object */
} cxx_exception_type;
#ifdef __i386__ /* CxxFrameHandler is not supported on non-i386 */
/* 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));
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) );
else
__asm__ __volatile__("pushl %2; call *%0"
: : "r" (func), "c" (this), "g" (src) );
}
/* call the destructor of the exception object */
inline static void call_dtor( void *func, void *object )
{
__asm__ __volatile__("call *%0" : : "r" (func), "c" (object) );
}
static void dump_type( cxx_type_info *type )
{
DPRINTF( "flags %x type %p", type->flags, type->type_info );
if (type->type_info) DPRINTF( " (%p %s)", type->type_info->data, type->type_info->name );
DPRINTF( " offset %d vbase %d,%d size %d copy ctor %p\n", type->this_offset,
type->vbase_descr, type->vbase_offset, type->size, type->copy_ctor );
}
static void dump_exception_type( cxx_exception_type *type )
{
int 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( cxx_function_descr *descr, cxx_exception_type *info )
{
int i, 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",
j, ptr->flags, ptr->offset, ptr->handler, ptr->type_info );
if (ptr->type_info) DPRINTF( " (%p %s)", ptr->type_info->data, ptr->type_info->name );
DPRINTF( "\n" );
}
}
}
/* compute the this pointer for a base class of a given type */
static void *get_this_pointer( cxx_type_info *type, void *object )
{
void *this_ptr;
int *offset_ptr;
if (!object) return NULL;
this_ptr = (char *)object + type->this_offset;
if (type->vbase_descr >= 0)
{
/* move this ptr to vbase descriptor */
this_ptr = (char *)this_ptr + type->vbase_descr;
/* and fetch additional offset from vbase descriptor */
offset_ptr = (int *)(*(char **)this_ptr + type->vbase_offset);
this_ptr = (char *)this_ptr + *offset_ptr;
}
return this_ptr;
}
/* check if the exception type is caught by a given catch block, and return the type that matched */
static 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++)
{
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->name, type->type_info->name )) 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, cxx_type_info *type )
{
void **dest_ptr;
if (!catchblock->type_info || !catchblock->type_info->name[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, 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, *dest_ptr );
}
else /* copy the object */
{
if (type->copy_ctor)
call_copy_ctor( type->copy_ctor, dest_ptr, get_this_pointer(type,object),
(type->flags & CLASS_HAS_VIRTUAL_BASE_CLASS) );
else
memmove( dest_ptr, get_this_pointer(type,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;
}
/* 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,
EXCEPTION_FRAME *unwind_frame,
cxx_function_descr *descr, int trylevel,
cxx_exception_type *info )
{
int i, j;
void *addr, *object = (void *)rec->ExceptionInformation[1];
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];
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( unwind_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 );
addr = call_ebp_func( catchblock->handler, &frame->ebp );
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_FRAME** dispatch,
cxx_function_descr *descr, 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) 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) goto normal_handler;
if (rec->ExceptionInformation[0] != CXX_FRAME_MAGIC) goto normal_handler;
if (exc_type->custom_handler)
return exc_type->custom_handler( rec, frame, exc_context, dispatch, descr, 0, 0, 0 );
normal_handler:
if (TRACE_ON(seh))
{
TRACE("handling C++ exception rec %p frame %p trylevel %d descr %p\n",
rec, frame, frame->trylevel, descr );
dump_exception_type( exc_type );
dump_function_descr( descr, exc_type );
}
next_ip = call_catch_block( rec, frame, (EXCEPTION_FRAME *)frame,
descr, frame->trylevel, exc_type );
if (!next_ip) return ExceptionContinueSearch;
context->Eip = (DWORD)next_ip;
context->Ebp = (DWORD)&frame->ebp;
context->Esp = ((DWORD*)frame)[-1];
return ExceptionContinueExecution;
}
/*********************************************************************
* __CxxFrameHandler (MSVCRT.@)
*/
void __CxxFrameHandler( PEXCEPTION_RECORD rec, EXCEPTION_FRAME* frame,
PCONTEXT exc_context, EXCEPTION_FRAME** 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, context );
}
#endif /* __i386__ */
/*********************************************************************
* _CxxThrowException (MSVCRT.@)
*/
void _CxxThrowException( void *object, 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 );
}