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 "wine/config.h"
#include "wine/port.h"

#include <stdarg.h>

#include "windef.h"
#include "winbase.h"
#include "winreg.h"
#include "winternl.h"
#include <internal/wine/msvcrt.h>
#include "wine/exception.h"
#include "excpt.h"
#include "wine/debug.h"

#include <internal/wine/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 );

/* 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 void dump_type( const cxx_type_info *type )
{
    DPRINTF( "flags %x type %p", type->flags, type->type_info );
    if (type->type_info) DPRINTF( " (%p %s)", type->type_info->name, type->type_info->mangled );
    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( 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",
                     j, ptr->flags, ptr->offset, ptr->handler, ptr->type_info );
            if (ptr->type_info) DPRINTF( " (%p %s)", ptr->type_info->name, ptr->type_info->mangled );
            DPRINTF( "\n" );
        }
    }
}

/* compute the this pointer for a base class of a given type */
static void *get_this_pointer( const 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 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, 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 >= (int)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",