Sweden-Number/dlls/vcruntime140_1/except_x86_64.c

/*
 * C++ exception handling (ver. 4)
 *
 * Copyright 2020 Piotr Caban
 *
 * 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#ifdef __x86_64__

#include "wine/exception.h"
#include "wine/debug.h"
#include "cppexcept.h"

WINE_DEFAULT_DEBUG_CHANNEL(seh);

#define CXX_EXCEPTION 0xe06d7363

static DWORD fls_index;

typedef struct
{
    BYTE header;
    UINT bbt_flags;
    UINT unwind_count;
    UINT unwind_map;
    UINT tryblock_count;
    UINT tryblock_map;
    UINT ip_count;
    UINT ip_map;
    UINT frame;
} cxx_function_descr;
#define FUNC_DESCR_IS_CATCH     0x01
#define FUNC_DESCR_IS_SEPARATED 0x02
#define FUNC_DESCR_BBT          0x04
#define FUNC_DESCR_UNWIND_MAP   0x08
#define FUNC_DESCR_TRYBLOCK_MAP 0x10
#define FUNC_DESCR_EHS          0x20
#define FUNC_DESCR_NO_EXCEPT    0x40
#define FUNC_DESCR_RESERVED     0x80

typedef struct
{
    UINT type;
    BYTE *prev;
    UINT handler;
    UINT object;
} unwind_info;

typedef struct
{
    BYTE header;
    UINT flags;
    UINT type_info;
    int offset;
    UINT handler;
    UINT ret_addr;
} catchblock_info;
#define CATCHBLOCK_FLAGS     0x01
#define CATCHBLOCK_TYPE_INFO 0x02
#define CATCHBLOCK_OFFSET    0x04
#define CATCHBLOCK_RET_ADDR  0x10

#define TYPE_FLAG_CONST      1
#define TYPE_FLAG_VOLATILE   2
#define TYPE_FLAG_REFERENCE  8

#define UNWIND_TYPE_NO_HANDLER 0
#define UNWIND_TYPE_DTOR_OBJ   1
#define UNWIND_TYPE_DTOR_PTR   2
#define UNWIND_TYPE_FRAME      3

typedef struct
{
    UINT start_level;
    UINT end_level;
    UINT catch_level;
    UINT catchblock_count;
    UINT catchblock;
} tryblock_info;

typedef struct
{
    UINT ip_off; /* relative to start of function or earlier ipmap_info */
    INT state;
} ipmap_info;

typedef struct
{
    cxx_frame_info frame_info;
    BOOL rethrow;
    INT search_state;
    INT unwind_state;
    EXCEPTION_RECORD *prev_rec;
} cxx_catch_ctx;

typedef struct
{
    ULONG64 dest_frame;
    ULONG64 orig_frame;
    EXCEPTION_RECORD *seh_rec;
    DISPATCHER_CONTEXT *dispatch;
    const cxx_function_descr *descr;
    int trylevel;
} se_translator_ctx;

static UINT decode_uint(BYTE **b)
{
    UINT ret;
    BYTE *p = *b;

    if ((*p & 1) == 0)
    {
        ret = p[0] >> 1;
        p += 1;
    }
    else if ((*p & 3) == 1)
    {
        ret = (p[0] >> 2) + (p[1] << 6);
        p += 2;
    }
    else if ((*p & 7) == 3)
    {
        ret = (p[0] >> 3) + (p[1] << 5) + (p[2] << 13);
        p += 3;
    }
    else if ((*p & 15) == 7)
    {
        ret = (p[0] >> 4) + (p[1] << 4) + (p[2] << 12) + (p[3] << 20);
        p += 4;
    }
    else
    {
        FIXME("not implemented - expect crash\n");
        ret = 0;
        p += 5;
    }

    *b = p;
    return ret;
}

static UINT read_rva(BYTE **b)
{
    UINT ret = *(UINT*)(*b);
    *b += sizeof(UINT);
    return ret;
}

static inline void* rva_to_ptr(UINT rva, ULONG64 base)
{
    return rva ? (void*)(base+rva) : NULL;
}

static void read_unwind_info(BYTE **b, unwind_info *ui)
{
    BYTE *p = *b;

    memset(ui, 0, sizeof(*ui));
    ui->type = decode_uint(b);
    ui->prev = p - (ui->type >> 2);
    ui->type &= 0x3;

    switch (ui->type)
    {
    case UNWIND_TYPE_NO_HANDLER:
        break;
    case UNWIND_TYPE_DTOR_OBJ:
        ui->handler = read_rva(b);
        ui->object = decode_uint(b); /* frame offset to object */
        break;
    case UNWIND_TYPE_DTOR_PTR:
        ui->handler = read_rva(b);
        ui->object = decode_uint(b); /* frame offset to pointer to object */
        break;
    case UNWIND_TYPE_FRAME:
        ui->handler = read_rva(b);
        break;
    }
}

static void read_tryblock_info(BYTE **b, tryblock_info *ti, ULONG64 image_base)
{
    BYTE *count, *count_end;

    ti->start_level = decode_uint(b);
    ti->end_level = decode_uint(b);
    ti->catch_level = decode_uint(b);
    ti->catchblock = read_rva(b);

    count = count_end = rva_to_ptr(ti->catchblock, image_base);
    if (count)
    {
        ti->catchblock_count = decode_uint(&count_end);
        ti->catchblock += count_end - count;
    }
    else
    {
        ti->catchblock_count = 0;
    }
}

static BOOL read_catchblock_info(BYTE **b, catchblock_info *ci)
{
    memset(ci, 0, sizeof(*ci));
    ci->header = **b;
    (*b)++;
    if (ci->header & ~(CATCHBLOCK_FLAGS | CATCHBLOCK_TYPE_INFO | CATCHBLOCK_OFFSET | CATCHBLOCK_RET_ADDR))
    {
        FIXME("unknown header: %x\n", ci->header);
        return FALSE;
    }
    if (ci->header & CATCHBLOCK_FLAGS) ci->flags = decode_uint(b);
    if (ci->header & CATCHBLOCK_TYPE_INFO) ci->type_info = read_rva(b);
    if (ci->header & CATCHBLOCK_OFFSET) ci->offset = decode_uint(b);
    ci->handler = read_rva(b);
    if (ci->header & CATCHBLOCK_RET_ADDR) ci->ret_addr = decode_uint(b);
    return TRUE;
}

static void read_ipmap_info(BYTE **b, ipmap_info *ii)
{
    ii->ip_off = decode_uint(b);
    ii->state = (INT)decode_uint(b) - 1;
}

static inline void dump_type(UINT type_rva, ULONG64 base)
{
    const cxx_type_info *type = rva_to_ptr(type_rva, base);

    TRACE("flags %x type %x %s offsets %d,%d,%d size %d copy ctor %x(%p)\n",
            type->flags, type->type_info, dbgstr_type_info(rva_to_ptr(type->type_info, base)),
            type->offsets.this_offset, type->offsets.vbase_descr, type->offsets.vbase_offset,
            type->size, type->copy_ctor, rva_to_ptr(type->copy_ctor, base));
}

static void dump_exception_type(const cxx_exception_type *type, ULONG64 base)
{
    const cxx_type_info_table *type_info_table = rva_to_ptr(type->type_info_table, base);
    UINT i;

    TRACE("flags %x destr %x(%p) handler %x(%p) type info %x(%p)\n",
            type->flags, type->destructor, rva_to_ptr(type->destructor, base),
            type->custom_handler, rva_to_ptr(type->custom_handler, base),
            type->type_info_table, type_info_table);
    for (i = 0; i < type_info_table->count; i++)
    {
        TRACE("    %d: ", i);
        dump_type(type_info_table->info[i], base);
    }
}

static BOOL validate_cxx_function_descr4(const cxx_function_descr *descr, DISPATCHER_CONTEXT *dispatch)
{
    ULONG64 image_base = dispatch->ImageBase;
    BYTE *unwind_map = rva_to_ptr(descr->unwind_map, image_base);
    BYTE *tryblock_map = rva_to_ptr(descr->tryblock_map, image_base);
    BYTE *ip_map = rva_to_ptr(descr->ip_map, image_base);
    UINT i, j;
    char *ip;

    TRACE("header 0x%x\n", descr->header);
    TRACE("basic block transformations flags: 0x%x\n", descr->bbt_flags);

    TRACE("unwind table: 0x%x(%p) %d\n", descr->unwind_map, unwind_map, descr->unwind_count);
    for (i = 0; i < descr->unwind_count; i++)
    {
        BYTE *entry = unwind_map;
        unwind_info ui;

        read_unwind_info(&unwind_map, &ui);
        if (ui.prev < (BYTE*)rva_to_ptr(descr->unwind_map, image_base)) ui.prev = NULL;
        TRACE("    %d (%p): type 0x%x prev %p func 0x%x(%p) object 0x%x\n",
                i, entry, ui.type, ui.prev, ui.handler,
                rva_to_ptr(ui.handler, image_base), ui.object);
    }

    TRACE("try table: 0x%x(%p) %d\n", descr->tryblock_map, tryblock_map, descr->tryblock_count);
    for (i = 0; i < descr->tryblock_count; i++)
    {
        tryblock_info ti;
        BYTE *catchblock;

        read_tryblock_info(&tryblock_map, &ti, image_base);
        catchblock = rva_to_ptr(ti.catchblock, image_base);
        TRACE("    %d: start %d end %d catchlevel %d catch 0x%x(%p) %d\n",
                i, ti.start_level, ti.end_level, ti.catch_level,
                ti.catchblock, catchblock, ti.catchblock_count);
        for (j = 0; j < ti.catchblock_count; j++)
        {
            catchblock_info ci;
            if (!read_catchblock_info(&catchblock, &ci)) return FALSE;
            TRACE("        %d: header 0x%x offset %d handler 0x%x(%p) "
                    "ret addr %x type %x %s\n", j, ci.header, ci.offset,
                    ci.handler, rva_to_ptr(ci.handler, image_base),
                    ci.ret_addr, ci.type_info,
                    dbgstr_type_info(rva_to_ptr(ci.type_info, image_base)));
        }
    }

    TRACE("ipmap: 0x%x(%p) %d\n", descr->ip_map, ip_map, descr->ip_count);
    ip = rva_to_ptr(dispatch->FunctionEntry->BeginAddress, image_base);
    for (i = 0; i < descr->ip_count; i++)
    {
        ipmap_info ii;

        read_ipmap_info(&ip_map, &ii);
        ip += ii.ip_off;
        TRACE("    %d: ip offset 0x%x (%p) state %d\n", i, ii.ip_off, ip, ii.state);
    }

    TRACE("establisher frame: %x\n", descr->frame);
    return TRUE;
}

static inline int ip_to_state4(BYTE *ip_map, UINT count, DISPATCHER_CONTEXT *dispatch, ULONG64 ip)
{
    ULONG64 state_ip;
    ipmap_info ii;
    int ret = -1;
    UINT i;

    state_ip = dispatch->ImageBase + dispatch->FunctionEntry->BeginAddress;
    for (i = 0; i < count; i++)
    {
        read_ipmap_info(&ip_map, &ii);
        state_ip += ii.ip_off;
        if (ip < state_ip) break;
        ret = ii.state;
    }

    TRACE("state %d\n", ret);
    return ret;
}

static const cxx_type_info *find_caught_type(cxx_exception_type *exc_type, ULONG64 exc_base,
                                             const type_info *catch_ti, UINT catch_flags)
{
    const cxx_type_info_table *type_info_table = rva_to_ptr(exc_type->type_info_table, exc_base);
    UINT i;

    for (i = 0; i < type_info_table->count; i++)
    {
        const cxx_type_info *type = rva_to_ptr(type_info_table->info[i], exc_base);
        const type_info *ti = rva_to_ptr(type->type_info, exc_base);

        if (!catch_ti) return type;   /* catch(...) matches any type */
        if (catch_ti != ti)
        {
            if (strcmp( catch_ti->mangled, ti->mangled )) continue;
        }
        /* type is the same, now check the flags */
        if ((exc_type->flags & TYPE_FLAG_CONST) &&
                !(catch_flags & TYPE_FLAG_CONST)) continue;
        if ((exc_type->flags & TYPE_FLAG_VOLATILE) &&
                !(catch_flags & TYPE_FLAG_VOLATILE)) continue;
        return type;  /* it matched */
    }
    return NULL;
}

static inline void copy_exception(void *object, ULONG64 frame, DISPATCHER_CONTEXT *dispatch,
        const catchblock_info *catchblock, const cxx_type_info *type, ULONG64 exc_base)
{
    const type_info *catch_ti = rva_to_ptr(catchblock->type_info, dispatch->ImageBase);
    void **dest = rva_to_ptr(catchblock->offset, frame);

    if (!catch_ti || !catch_ti->mangled[0]) return;
    if (!catchblock->offset) return;

    if (catchblock->flags & TYPE_FLAG_REFERENCE)
    {
        *dest = get_this_pointer(&type->offsets, object);
    }
    else if (type->flags & CLASS_IS_SIMPLE_TYPE)
    {
        memmove(dest, object, type->size);
        /* if it is a pointer, adjust it */
        if (type->size == sizeof(void*)) *dest = get_this_pointer(&type->offsets, *dest);
    }
    else  /* copy the object */
    {
        if (type->copy_ctor)
        {
            if (type->flags & CLASS_HAS_VIRTUAL_BASE_CLASS)
            {
                void (__cdecl *copy_ctor)(void*, void*, int) =
                    rva_to_ptr(type->copy_ctor, exc_base);
                copy_ctor(dest, get_this_pointer(&type->offsets, object), 1);
            }
            else
            {
                void (__cdecl *copy_ctor)(void*, void*) =
                    rva_to_ptr(type->copy_ctor, exc_base);
                copy_ctor(dest, get_this_pointer(&type->offsets, object));
            }
        }
        else
            memmove(dest, get_this_pointer(&type->offsets,object), type->size);
    }
}

static void cxx_local_unwind4(ULONG64 frame, DISPATCHER_CONTEXT *dispatch,
        const cxx_function_descr *descr, int trylevel, int last_level)
{
    void (__cdecl *handler_dtor)(void *obj, ULONG64 frame);
    BYTE *unwind_data, *last;
    unwind_info ui;
    void *obj;
    int i;

    if (trylevel == -2)
    {
        trylevel = ip_to_state4(rva_to_ptr(descr->ip_map, dispatch->ImageBase),
                descr->ip_count, dispatch, dispatch->ControlPc);
    }

    TRACE("current level: %d, last level: %d\n", trylevel, last_level);

    if (trylevel<-1 || trylevel>=(int)descr->unwind_count)
    {
        ERR("invalid trylevel %d\n", trylevel);
        terminate();
    }

    if (trylevel <= last_level) return;

    unwind_data = rva_to_ptr(descr->unwind_map, dispatch->ImageBase);
    last = unwind_data - 1;
    for (i = 0; i < trylevel; i++)
    {
        BYTE *addr = unwind_data;
        read_unwind_info(&unwind_data, &ui);
        if (i == last_level) last = addr;
    }

    while (unwind_data > last)
    {
        read_unwind_info(&unwind_data, &ui);
        unwind_data = ui.prev;

        if (ui.handler)
        {
            handler_dtor = rva_to_ptr(ui.handler, dispatch->ImageBase);
            obj = rva_to_ptr(ui.object, frame);
            if(ui.type == UNWIND_TYPE_DTOR_PTR)
                obj = *(void**)obj;
            TRACE("handler: %p object: %p\n", handler_dtor, obj);
            handler_dtor(obj, frame);
        }
    }
}

static LONG CALLBACK cxx_rethrow_filter(PEXCEPTION_POINTERS eptrs, void *c)
{
    EXCEPTION_RECORD *rec = eptrs->ExceptionRecord;
    cxx_catch_ctx *ctx = c;

    if (rec->ExceptionCode == CXX_EXCEPTION && !rec->ExceptionInformation[1] && !rec->ExceptionInformation[2])
        return EXCEPTION_EXECUTE_HANDLER;

    FlsSetValue(fls_index, (void*)(DWORD_PTR)ctx->search_state);
    if (rec->ExceptionCode != CXX_EXCEPTION)
        return EXCEPTION_CONTINUE_SEARCH;
    if (rec->ExceptionInformation[1] == ctx->prev_rec->ExceptionInformation[1])
        ctx->rethrow = TRUE;
    return EXCEPTION_CONTINUE_SEARCH;
}

static void CALLBACK cxx_catch_cleanup(BOOL normal, void *c)
{
    cxx_catch_ctx *ctx = c;
    __CxxUnregisterExceptionObject(&ctx->frame_info, ctx->rethrow);

    FlsSetValue(fls_index, (void*)(DWORD_PTR)ctx->unwind_state);
}

static void* WINAPI call_catch_block4(EXCEPTION_RECORD *rec)
{
    ULONG64 frame = rec->ExceptionInformation[1];
    EXCEPTION_RECORD *prev_rec = (void*)rec->ExceptionInformation[4];
    EXCEPTION_RECORD *untrans_rec = (void*)rec->ExceptionInformation[6];
    CONTEXT *context = (void*)rec->ExceptionInformation[7];
    void* (__cdecl *handler)(ULONG64 unk, ULONG64 rbp) = (void*)rec->ExceptionInformation[5];
    EXCEPTION_POINTERS ep = { prev_rec, context };
    cxx_catch_ctx ctx;
    void *ret_addr = NULL;

    TRACE("calling handler %p\n", handler);

    ctx.rethrow = FALSE;
    __CxxRegisterExceptionObject(&ep, &ctx.frame_info);
    ctx.search_state = rec->ExceptionInformation[2];
    ctx.unwind_state = rec->ExceptionInformation[3];
    ctx.prev_rec = prev_rec;
    (*__processing_throw())--;
    __TRY
    {
        __TRY
        {
            ret_addr = handler(0, frame);
        }
        __EXCEPT_CTX(cxx_rethrow_filter, &ctx)
        {
            TRACE("detect rethrow: exception code: %x\n", prev_rec->ExceptionCode);
            ctx.rethrow = TRUE;
            FlsSetValue(fls_index, (void*)(DWORD_PTR)ctx.search_state);

            if (untrans_rec)
            {
                __DestructExceptionObject(prev_rec);
                RaiseException(untrans_rec->ExceptionCode, untrans_rec->ExceptionFlags,
                        untrans_rec->NumberParameters, untrans_rec->ExceptionInformation);
            }
            else
            {
                RaiseException(prev_rec->ExceptionCode, prev_rec->ExceptionFlags,
                        prev_rec->NumberParameters, prev_rec->ExceptionInformation);
            }
        }
        __ENDTRY
    }
    __FINALLY_CTX(cxx_catch_cleanup, &ctx)

    FlsSetValue(fls_index, (void*)-2);
    if (rec->ExceptionInformation[8]) return (void*)rec->ExceptionInformation[8];
    return ret_addr;
}

static inline BOOL cxx_is_consolidate(const EXCEPTION_RECORD *rec)
{
    return rec->ExceptionCode==STATUS_UNWIND_CONSOLIDATE && rec->NumberParameters==9 &&
        rec->ExceptionInformation[0]==(ULONG_PTR)call_catch_block4;
}

static inline void find_catch_block4(EXCEPTION_RECORD *rec, CONTEXT *context,
        EXCEPTION_RECORD *untrans_rec, ULONG64 frame, DISPATCHER_CONTEXT *dispatch,
        const cxx_function_descr *descr, cxx_exception_type *info,
        ULONG64 orig_frame, int trylevel)
{
    ULONG64 exc_base = (rec->NumberParameters == 4 ? rec->ExceptionInformation[3] : 0);
    int *processing_throw = __processing_throw();
    EXCEPTION_RECORD catch_record;
    BYTE *tryblock_map;
    CONTEXT ctx;
    UINT i, j;

    (*processing_throw)++;

    if (trylevel == -2)
    {
        trylevel = ip_to_state4(rva_to_ptr(descr->ip_map, dispatch->ImageBase),
                descr->ip_count, dispatch, dispatch->ControlPc);
    }
    TRACE("current trylevel: %d\n", trylevel);

    tryblock_map = rva_to_ptr(descr->tryblock_map, dispatch->ImageBase);
    for (i=0; i<descr->tryblock_count; i++)
    {
        tryblock_info tryblock;
        BYTE *catchblock;

        read_tryblock_info(&tryblock_map, &tryblock, dispatch->ImageBase);

        if (trylevel < tryblock.start_level) continue;
        if (trylevel > tryblock.end_level) continue;

        /* got a try block */
        catchblock = rva_to_ptr(tryblock.catchblock, dispatch->ImageBase);
        for (j=0; j<tryblock.catchblock_count; j++)
        {
            catchblock_info ci;

            read_catchblock_info(&catchblock, &ci);

            if (info)
            {
                const cxx_type_info *type = find_caught_type(info, exc_base,
                        rva_to_ptr(ci.type_info, dispatch->ImageBase),
                        ci.flags);
                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((void*)rec->ExceptionInformation[1],
                        orig_frame, dispatch, &ci, type, exc_base);
            }
            else
            {
                /* no CXX_EXCEPTION only proceed with a catch(...) block*/
                if (ci.type_info)
                    continue;
                TRACE("found catch(...) block\n");
            }

            /* unwind stack and call catch */
            memset(&catch_record, 0, sizeof(catch_record));
            catch_record.ExceptionCode = STATUS_UNWIND_CONSOLIDATE;
            catch_record.ExceptionFlags = EXCEPTION_NONCONTINUABLE;
            catch_record.NumberParameters = 9;
            catch_record.ExceptionInformation[0] = (ULONG_PTR)call_catch_block4;
            catch_record.ExceptionInformation[1] = orig_frame;
            catch_record.ExceptionInformation[2] = tryblock.catch_level;
            catch_record.ExceptionInformation[3] = tryblock.start_level;
            catch_record.ExceptionInformation[4] = (ULONG_PTR)rec;
            catch_record.ExceptionInformation[5] =
                (ULONG_PTR)rva_to_ptr(ci.handler, dispatch->ImageBase);
            catch_record.ExceptionInformation[6] = (ULONG_PTR)untrans_rec;
            catch_record.ExceptionInformation[7] = (ULONG_PTR)context;
            if (ci.ret_addr)
                catch_record.ExceptionInformation[8] = (ULONG_PTR)rva_to_ptr(
                    ci.ret_addr + dispatch->FunctionEntry->BeginAddress, dispatch->ImageBase);
            RtlUnwindEx((void*)frame, (void*)dispatch->ControlPc, &catch_record, NULL, &ctx, NULL);
        }
    }

    TRACE("no matching catch block found\n");
    (*processing_throw)--;
}

static LONG CALLBACK se_translation_filter(EXCEPTION_POINTERS *ep, void *c)
{
    se_translator_ctx *ctx = (se_translator_ctx *)c;
    EXCEPTION_RECORD *rec = ep->ExceptionRecord;
    cxx_exception_type *exc_type;

    if (rec->ExceptionCode != CXX_EXCEPTION)
    {
        TRACE("non-c++ exception thrown in SEH handler: %x\n", rec->ExceptionCode);
        terminate();
    }

    exc_type = (cxx_exception_type *)rec->ExceptionInformation[2];
    find_catch_block4(rec, ep->ContextRecord, ctx->seh_rec, ctx->dest_frame, ctx->dispatch,
            ctx->descr, exc_type, ctx->orig_frame, ctx->trylevel);

    __DestructExceptionObject(rec);
    return ExceptionContinueSearch;
}

/* Hacky way to obtain se_translator */
static inline _se_translator_function get_se_translator(void)
{
    return __current_exception()[-2];
}

static void check_noexcept( PEXCEPTION_RECORD rec, const cxx_function_descr *descr )
{
    if (!(descr->header & FUNC_DESCR_IS_CATCH) &&
            rec->ExceptionCode == CXX_EXCEPTION &&
            (descr->header & FUNC_DESCR_NO_EXCEPT))
    {
        ERR("noexcept function propagating exception\n");
        terminate();
    }
}

static DWORD cxx_frame_handler4(EXCEPTION_RECORD *rec, ULONG64 frame,
        CONTEXT *context, DISPATCHER_CONTEXT *dispatch,
        const cxx_function_descr *descr, int trylevel)
{
    cxx_exception_type *exc_type;
    ULONG64 orig_frame = frame;

    if (descr->header & FUNC_DESCR_IS_CATCH)
    {
        TRACE("nested exception detected\n");
        orig_frame = *(ULONG64*)rva_to_ptr(descr->frame, frame);
        TRACE("setting orig_frame to %lx\n", orig_frame);
    }

    if (rec->ExceptionFlags & (EH_UNWINDING|EH_EXIT_UNWIND))
    {
        int last_level = -1;
        if ((rec->ExceptionFlags & EH_TARGET_UNWIND) && cxx_is_consolidate(rec))
            last_level = rec->ExceptionInformation[3];
        else if ((rec->ExceptionFlags & EH_TARGET_UNWIND) && rec->ExceptionCode == STATUS_LONGJUMP)
            last_level = ip_to_state4(rva_to_ptr(descr->ip_map, dispatch->ImageBase),
                    descr->ip_count, dispatch, dispatch->TargetIp);

        cxx_local_unwind4(orig_frame, dispatch, descr, trylevel, last_level);
        return ExceptionContinueSearch;
    }
    if (!descr->tryblock_map)
    {
        check_noexcept(rec, descr);
        return ExceptionContinueSearch;
    }

    if (rec->ExceptionCode == CXX_EXCEPTION)
    {
        if (!rec->ExceptionInformation[1] && !rec->ExceptionInformation[2])
        {
            TRACE("rethrow detected.\n");
            *rec = *(EXCEPTION_RECORD*)*__current_exception();
        }

        exc_type = (cxx_exception_type *)rec->ExceptionInformation[2];

        if (TRACE_ON(seh))
        {
            TRACE("handling C++ exception rec %p frame %lx descr %p\n", rec, frame,  descr);
            dump_exception_type(exc_type, rec->ExceptionInformation[3]);
        }
    }
    else
    {
        _se_translator_function se_translator = get_se_translator();

        exc_type = NULL;
        TRACE("handling C exception code %x rec %p frame %lx descr %p\n",
                rec->ExceptionCode, rec, frame, descr);

        if (se_translator) {
            EXCEPTION_POINTERS except_ptrs;
            se_translator_ctx ctx;

            ctx.dest_frame = frame;
            ctx.orig_frame = orig_frame;
            ctx.seh_rec    = rec;
            ctx.dispatch   = dispatch;
            ctx.descr      = descr;
            ctx.trylevel   = trylevel;
            __TRY
            {
                except_ptrs.ExceptionRecord = rec;
                except_ptrs.ContextRecord = context;
                se_translator(rec->ExceptionCode, &except_ptrs);
            }
            __EXCEPT_CTX(se_translation_filter, &ctx)
            {
            }
            __ENDTRY
        }
    }

    find_catch_block4(rec, context, NULL, frame, dispatch, descr, exc_type, orig_frame, trylevel);
    check_noexcept(rec, descr);
    return ExceptionContinueSearch;
}

EXCEPTION_DISPOSITION __cdecl __CxxFrameHandler4(EXCEPTION_RECORD *rec,
        ULONG64 frame, CONTEXT *context, DISPATCHER_CONTEXT *dispatch)
{
    cxx_function_descr descr;
    BYTE *p, *count, *count_end;
    int trylevel;

    TRACE("%p %lx %p %p\n", rec, frame, context, dispatch);

    trylevel = (DWORD_PTR)FlsGetValue(fls_index);
    FlsSetValue(fls_index, (void*)-2);

    memset(&descr, 0, sizeof(descr));
    p = rva_to_ptr(*(UINT*)dispatch->HandlerData, dispatch->ImageBase);
    descr.header = *p++;

    if ((descr.header & FUNC_DESCR_EHS) &&
            rec->ExceptionCode != CXX_EXCEPTION &&
            !cxx_is_consolidate(rec) &&
            rec->ExceptionCode != STATUS_LONGJUMP)
        return ExceptionContinueSearch;  /* handle only c++ exceptions */

    if (descr.header & ~(FUNC_DESCR_IS_CATCH | FUNC_DESCR_UNWIND_MAP |
                FUNC_DESCR_TRYBLOCK_MAP | FUNC_DESCR_EHS | FUNC_DESCR_NO_EXCEPT))
    {
        FIXME("unsupported flags: %x\n", descr.header);
        return ExceptionContinueSearch;
    }

    if (descr.header & FUNC_DESCR_BBT) descr.bbt_flags = decode_uint(&p);
    if (descr.header & FUNC_DESCR_UNWIND_MAP)
    {
        descr.unwind_map = read_rva(&p);
        count_end = count = rva_to_ptr(descr.unwind_map, dispatch->ImageBase);
        descr.unwind_count = decode_uint(&count_end);
        descr.unwind_map += count_end - count;
    }
    if (descr.header & FUNC_DESCR_TRYBLOCK_MAP)
    {
        descr.tryblock_map = read_rva(&p);
        count_end = count = rva_to_ptr(descr.tryblock_map, dispatch->ImageBase);
        descr.tryblock_count = decode_uint(&count_end);
        descr.tryblock_map += count_end - count;
    }
    descr.ip_map = read_rva(&p);
    count_end = count = rva_to_ptr(descr.ip_map, dispatch->ImageBase);
    descr.ip_count = decode_uint(&count_end);
    descr.ip_map += count_end - count;
    if (descr.header & FUNC_DESCR_IS_CATCH) descr.frame = decode_uint(&p);

    if (!validate_cxx_function_descr4(&descr, dispatch))
        return ExceptionContinueSearch;

    return cxx_frame_handler4(rec, frame, context, dispatch, &descr, trylevel);
}

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID reserved)
{
    switch (fdwReason)
    {
    case DLL_PROCESS_ATTACH:
        fls_index = FlsAlloc(NULL);
        if (fls_index == FLS_OUT_OF_INDEXES)
            return FALSE;
        /* fall through */
    case DLL_THREAD_ATTACH:
        FlsSetValue(fls_index, (void*)-2);
        break;
    case DLL_PROCESS_DETACH:
        if (reserved) break;
        FlsFree(fls_index);
        break;
    }
    return TRUE;
}

#endif