496 lines
18 KiB
C
496 lines
18 KiB
C
/*
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* msvcrt C++ exception handling
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*
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* Copyright 2002 Alexandre Julliard
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* NOTES
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* A good reference is the article "How a C++ compiler implements
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* exception handling" by Vishal Kochhar, available on
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* www.thecodeproject.com.
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*/
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#include "config.h"
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#include "wine/port.h"
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#include "winternl.h"
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#include "msvcrt.h"
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#include "wine/exception.h"
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#include "msvcrt/excpt.h"
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#include "wine/debug.h"
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WINE_DEFAULT_DEBUG_CHANNEL(seh);
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#define CXX_FRAME_MAGIC 0x19930520
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#define CXX_EXCEPTION 0xe06d7363
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typedef struct __type_info
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{
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void *vtable;
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void *data;
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char name[1];
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} type_info;
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/* the exception frame used by CxxFrameHandler */
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typedef struct __cxx_exception_frame
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{
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EXCEPTION_FRAME frame; /* the standard exception frame */
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int trylevel;
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DWORD ebp;
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} cxx_exception_frame;
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/* info about a single catch {} block */
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typedef struct __catchblock_info
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{
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UINT flags; /* flags (see below) */
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type_info *type_info; /* C++ type caught by this block */
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int offset; /* stack offset to copy exception object to */
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void (*handler)(); /* catch block handler code */
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} catchblock_info;
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#define TYPE_FLAG_CONST 1
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#define TYPE_FLAG_VOLATILE 2
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#define TYPE_FLAG_REFERENCE 8
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/* info about a single try {} block */
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typedef struct __tryblock_info
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{
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int start_level; /* start trylevel of that block */
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int end_level; /* end trylevel of that block */
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int catch_level; /* initial trylevel of the catch block */
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int catchblock_count; /* count of catch blocks in array */
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catchblock_info *catchblock; /* array of catch blocks */
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} tryblock_info;
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/* info about the unwind handler for a given trylevel */
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typedef struct __unwind_info
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{
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int prev; /* prev trylevel unwind handler, to run after this one */
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void (*handler)(); /* unwind handler */
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} unwind_info;
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/* descriptor of all try blocks of a given function */
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typedef struct __cxx_function_descr
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{
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UINT magic; /* must be CXX_FRAME_MAGIC */
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UINT unwind_count; /* number of unwind handlers */
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unwind_info *unwind_table; /* array of unwind handlers */
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UINT tryblock_count; /* number of try blocks */
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tryblock_info *tryblock; /* array of try blocks */
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UINT unknown[3];
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} cxx_function_descr;
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/* complete information about a C++ type */
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typedef struct __cxx_type_info
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{
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UINT flags; /* flags (see CLASS_* flags below) */
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type_info *type_info; /* C++ type info */
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int this_offset; /* offset of base class this pointer from start of object */
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int vbase_descr; /* offset of virtual base class descriptor */
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int vbase_offset; /* offset of this pointer offset in virtual base class descriptor */
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size_t size; /* object size */
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void (*copy_ctor)(); /* copy constructor */
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} cxx_type_info;
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#define CLASS_IS_SIMPLE_TYPE 1
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#define CLASS_HAS_VIRTUAL_BASE_CLASS 4
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/* table of C++ types that apply for a given object */
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typedef struct __cxx_type_info_table
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{
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UINT count; /* number of types */
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cxx_type_info *info[1]; /* array of types */
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} cxx_type_info_table;
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typedef DWORD (*cxx_exc_custom_handler)( PEXCEPTION_RECORD, cxx_exception_frame*,
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PCONTEXT, struct __EXCEPTION_FRAME**,
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cxx_function_descr*, int nested_trylevel,
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EXCEPTION_FRAME *nested_frame, DWORD unknown3 );
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/* type information for an exception object */
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typedef struct __cxx_exception_type
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{
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UINT flags; /* TYPE_FLAG flags */
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void (*destructor)(); /* exception object destructor */
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cxx_exc_custom_handler custom_handler; /* custom handler for this exception */
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cxx_type_info_table *type_info_table; /* list of types for this exception object */
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} cxx_exception_type;
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#ifdef __i386__ /* CxxFrameHandler is not supported on non-i386 */
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static DWORD cxx_frame_handler( PEXCEPTION_RECORD rec, cxx_exception_frame* frame,
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PCONTEXT exc_context, EXCEPTION_FRAME** dispatch,
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cxx_function_descr *descr, EXCEPTION_FRAME* nested_frame,
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int nested_trylevel, CONTEXT86 *context );
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/* call a function with a given ebp */
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inline static void *call_ebp_func( void *func, void *ebp )
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{
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void *ret;
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__asm__ __volatile__ ("pushl %%ebp; movl %2,%%ebp; call *%%eax; popl %%ebp" \
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: "=a" (ret) : "0" (func), "g" (ebp) : "ecx", "edx", "memory" );
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return ret;
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}
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/* call a copy constructor */
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inline static void call_copy_ctor( void *func, void *this, void *src, int has_vbase )
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{
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TRACE( "calling copy ctor %p object %p src %p\n", func, this, src );
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if (has_vbase)
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/* in that case copy ctor takes an extra bool indicating whether to copy the base class */
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__asm__ __volatile__("pushl $1; pushl %2; call *%0"
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: : "r" (func), "c" (this), "g" (src) : "eax", "edx", "memory" );
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else
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__asm__ __volatile__("pushl %2; call *%0"
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: : "r" (func), "c" (this), "g" (src) : "eax", "edx", "memory" );
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}
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/* call the destructor of the exception object */
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inline static void call_dtor( void *func, void *object )
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{
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__asm__ __volatile__("call *%0" : : "r" (func), "c" (object) : "eax", "edx", "memory" );
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}
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static void dump_type( cxx_type_info *type )
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{
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DPRINTF( "flags %x type %p", type->flags, type->type_info );
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if (type->type_info) DPRINTF( " (%p %s)", type->type_info->data, type->type_info->name );
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DPRINTF( " offset %d vbase %d,%d size %d copy ctor %p\n", type->this_offset,
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type->vbase_descr, type->vbase_offset, type->size, type->copy_ctor );
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}
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static void dump_exception_type( cxx_exception_type *type )
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{
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int i;
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DPRINTF( "exception type:\n" );
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DPRINTF( "flags %x destr %p handler %p type info %p\n",
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type->flags, type->destructor, type->custom_handler, type->type_info_table );
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for (i = 0; i < type->type_info_table->count; i++)
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{
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DPRINTF( " %d: ", i );
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dump_type( type->type_info_table->info[i] );
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}
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}
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static void dump_function_descr( cxx_function_descr *descr, cxx_exception_type *info )
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{
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int i, j;
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DPRINTF( "function descr:\n" );
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DPRINTF( "magic %x\n", descr->magic );
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DPRINTF( "unwind table: %p %d\n", descr->unwind_table, descr->unwind_count );
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for (i = 0; i < descr->unwind_count; i++)
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{
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DPRINTF( " %d: prev %d func %p\n", i,
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descr->unwind_table[i].prev, descr->unwind_table[i].handler );
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}
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DPRINTF( "try table: %p %d\n", descr->tryblock, descr->tryblock_count );
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for (i = 0; i < descr->tryblock_count; i++)
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{
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DPRINTF( " %d: start %d end %d catchlevel %d catch %p %d\n", i,
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descr->tryblock[i].start_level, descr->tryblock[i].end_level,
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descr->tryblock[i].catch_level, descr->tryblock[i].catchblock,
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descr->tryblock[i].catchblock_count );
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for (j = 0; j < descr->tryblock[i].catchblock_count; j++)
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{
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catchblock_info *ptr = &descr->tryblock[i].catchblock[j];
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DPRINTF( " %d: flags %x offset %d handler %p type %p",
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j, ptr->flags, ptr->offset, ptr->handler, ptr->type_info );
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if (ptr->type_info) DPRINTF( " (%p %s)", ptr->type_info->data, ptr->type_info->name );
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DPRINTF( "\n" );
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}
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}
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}
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/* compute the this pointer for a base class of a given type */
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static void *get_this_pointer( cxx_type_info *type, void *object )
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{
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void *this_ptr;
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int *offset_ptr;
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if (!object) return NULL;
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this_ptr = (char *)object + type->this_offset;
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if (type->vbase_descr >= 0)
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{
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/* move this ptr to vbase descriptor */
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this_ptr = (char *)this_ptr + type->vbase_descr;
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/* and fetch additional offset from vbase descriptor */
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offset_ptr = (int *)(*(char **)this_ptr + type->vbase_offset);
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this_ptr = (char *)this_ptr + *offset_ptr;
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}
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return this_ptr;
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}
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/* check if the exception type is caught by a given catch block, and return the type that matched */
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static cxx_type_info *find_caught_type( cxx_exception_type *exc_type, catchblock_info *catchblock )
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{
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UINT i;
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for (i = 0; i < exc_type->type_info_table->count; i++)
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{
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cxx_type_info *type = exc_type->type_info_table->info[i];
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if (!catchblock->type_info) return type; /* catch(...) matches any type */
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if (catchblock->type_info != type->type_info)
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{
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if (strcmp( catchblock->type_info->name, type->type_info->name )) continue;
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}
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/* type is the same, now check the flags */
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if ((exc_type->flags & TYPE_FLAG_CONST) &&
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!(catchblock->flags & TYPE_FLAG_CONST)) continue;
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if ((exc_type->flags & TYPE_FLAG_VOLATILE) &&
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!(catchblock->flags & TYPE_FLAG_VOLATILE)) continue;
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return type; /* it matched */
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}
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return NULL;
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}
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/* copy the exception object where the catch block wants it */
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static void copy_exception( void *object, cxx_exception_frame *frame,
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catchblock_info *catchblock, cxx_type_info *type )
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{
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void **dest_ptr;
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if (!catchblock->type_info || !catchblock->type_info->name[0]) return;
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if (!catchblock->offset) return;
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dest_ptr = (void **)((char *)&frame->ebp + catchblock->offset);
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if (catchblock->flags & TYPE_FLAG_REFERENCE)
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{
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*dest_ptr = get_this_pointer( type, object );
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}
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else if (type->flags & CLASS_IS_SIMPLE_TYPE)
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{
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memmove( dest_ptr, object, type->size );
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/* if it is a pointer, adjust it */
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if (type->size == sizeof(void *)) *dest_ptr = get_this_pointer( type, *dest_ptr );
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}
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else /* copy the object */
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{
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if (type->copy_ctor)
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call_copy_ctor( type->copy_ctor, dest_ptr, get_this_pointer(type,object),
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(type->flags & CLASS_HAS_VIRTUAL_BASE_CLASS) );
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else
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memmove( dest_ptr, get_this_pointer(type,object), type->size );
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}
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}
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/* unwind the local function up to a given trylevel */
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static void cxx_local_unwind( cxx_exception_frame* frame, cxx_function_descr *descr, int last_level)
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{
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void (*handler)();
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int trylevel = frame->trylevel;
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while (trylevel != last_level)
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{
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if (trylevel < 0 || trylevel >= descr->unwind_count)
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{
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ERR( "invalid trylevel %d\n", trylevel );
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MSVCRT_terminate();
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}
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handler = descr->unwind_table[trylevel].handler;
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if (handler)
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{
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TRACE( "calling unwind handler %p trylevel %d last %d ebp %p\n",
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handler, trylevel, last_level, &frame->ebp );
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call_ebp_func( handler, &frame->ebp );
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}
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trylevel = descr->unwind_table[trylevel].prev;
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}
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frame->trylevel = last_level;
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}
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/* exception frame for nested exceptions in catch block */
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struct catch_func_nested_frame
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{
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EXCEPTION_FRAME frame; /* standard exception frame */
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EXCEPTION_RECORD *prev_rec; /* previous record to restore in thread data */
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cxx_exception_frame *cxx_frame; /* frame of parent exception */
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cxx_function_descr *descr; /* descriptor of parent exception */
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int trylevel; /* current try level */
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};
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/* handler for exceptions happening while calling a catch function */
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static DWORD catch_function_nested_handler( EXCEPTION_RECORD *rec, EXCEPTION_FRAME *frame,
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CONTEXT *context, EXCEPTION_FRAME **dispatcher )
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{
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struct catch_func_nested_frame *nested_frame = (struct catch_func_nested_frame *)frame;
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if (rec->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND))
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{
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msvcrt_get_thread_data()->exc_record = nested_frame->prev_rec;
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return ExceptionContinueSearch;
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}
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else
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{
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TRACE( "got nested exception in catch function\n" );
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return cxx_frame_handler( rec, nested_frame->cxx_frame, context,
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NULL, nested_frame->descr, &nested_frame->frame,
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nested_frame->trylevel, context );
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}
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}
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/* find and call the appropriate catch block for an exception */
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/* returns the address to continue execution to after the catch block was called */
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inline static void *call_catch_block( PEXCEPTION_RECORD rec, cxx_exception_frame *frame,
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cxx_function_descr *descr, int nested_trylevel,
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cxx_exception_type *info )
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{
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int i, j;
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void *addr, *object = (void *)rec->ExceptionInformation[1];
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struct catch_func_nested_frame nested_frame;
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int trylevel = frame->trylevel;
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MSVCRT_thread_data *thread_data = msvcrt_get_thread_data();
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for (i = 0; i < descr->tryblock_count; i++)
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{
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tryblock_info *tryblock = &descr->tryblock[i];
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if (trylevel < tryblock->start_level) continue;
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if (trylevel > tryblock->end_level) continue;
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/* got a try block */
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for (j = 0; j < tryblock->catchblock_count; j++)
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{
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catchblock_info *catchblock = &tryblock->catchblock[j];
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cxx_type_info *type = find_caught_type( info, catchblock );
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if (!type) continue;
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TRACE( "matched type %p in tryblock %d catchblock %d\n", type, i, j );
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/* copy the exception to its destination on the stack */
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copy_exception( object, frame, catchblock, type );
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/* unwind the stack */
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RtlUnwind( frame, 0, rec, 0 );
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cxx_local_unwind( frame, descr, tryblock->start_level );
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frame->trylevel = tryblock->end_level + 1;
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/* call the catch block */
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TRACE( "calling catch block %p for type %p addr %p ebp %p\n",
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catchblock, type, catchblock->handler, &frame->ebp );
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/* setup an exception block for nested exceptions */
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nested_frame.frame.Handler = catch_function_nested_handler;
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nested_frame.prev_rec = thread_data->exc_record;
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nested_frame.cxx_frame = frame;
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nested_frame.descr = descr;
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nested_frame.trylevel = nested_trylevel + 1;
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__wine_push_frame( &nested_frame.frame );
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thread_data->exc_record = rec;
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addr = call_ebp_func( catchblock->handler, &frame->ebp );
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thread_data->exc_record = nested_frame.prev_rec;
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__wine_pop_frame( &nested_frame.frame );
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if (info->destructor) call_dtor( info->destructor, object );
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TRACE( "done, continuing at %p\n", addr );
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return addr;
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}
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}
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return NULL;
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}
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/*********************************************************************
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* cxx_frame_handler
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*
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* Implementation of __CxxFrameHandler.
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*/
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static DWORD cxx_frame_handler( PEXCEPTION_RECORD rec, cxx_exception_frame* frame,
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PCONTEXT exc_context, EXCEPTION_FRAME** dispatch,
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cxx_function_descr *descr, EXCEPTION_FRAME* nested_frame,
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int nested_trylevel, CONTEXT86 *context )
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{
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cxx_exception_type *exc_type;
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void *next_ip;
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if (descr->magic != CXX_FRAME_MAGIC)
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{
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ERR( "invalid frame magic %x\n", descr->magic );
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return ExceptionContinueSearch;
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}
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if (rec->ExceptionFlags & (EH_UNWINDING|EH_EXIT_UNWIND))
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{
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if (descr->unwind_count && !nested_trylevel) cxx_local_unwind( frame, descr, -1 );
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return ExceptionContinueSearch;
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}
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if (!descr->tryblock_count) return ExceptionContinueSearch;
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exc_type = (cxx_exception_type *)rec->ExceptionInformation[2];
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if (rec->ExceptionCode == CXX_EXCEPTION &&
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rec->ExceptionInformation[0] > CXX_FRAME_MAGIC &&
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exc_type->custom_handler)
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{
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return exc_type->custom_handler( rec, frame, exc_context, dispatch,
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descr, nested_trylevel, nested_frame, 0 );
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}
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if (!exc_type) /* nested exception, fetch info from original exception */
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{
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rec = msvcrt_get_thread_data()->exc_record;
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exc_type = (cxx_exception_type *)rec->ExceptionInformation[2];
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}
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if (TRACE_ON(seh))
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{
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TRACE("handling C++ exception rec %p frame %p trylevel %d descr %p nested_frame %p\n",
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rec, frame, frame->trylevel, descr, nested_frame );
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dump_exception_type( exc_type );
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dump_function_descr( descr, exc_type );
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}
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next_ip = call_catch_block( rec, frame, descr, frame->trylevel, exc_type );
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if (!next_ip) return ExceptionContinueSearch;
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rec->ExceptionFlags &= ~EH_NONCONTINUABLE;
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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, NULL, 0, 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 );
|
|
}
|