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/* Static condition handler for Alpha/VMS.
Copyright (C) 2005-2021 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published
by the Free Software Foundation; either version 3, or (at your
option) any later version.
GCC is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
License for more details.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<>. */
/* This file implements __gcc_shell_handler, the static VMS condition handler
used as the indirection wrapper around user level handlers installed with
establish_vms_condition_handler GCC builtin.
[ABI] in comments refers to the "HP OpenVMS calling standard" document
dated January 2005. */
#include <vms/chfdef.h>
#include <vms/pdscdef.h>
#include <vms/ssdef.h>
typedef void * ADDR;
typedef unsigned long long REG;
#define REG_AT(addr) (*(REG *)(addr))
/* Compute pointer to procedure descriptor (Procedure Value) from Frame
Pointer FP, according to the rules in [ABI-3.5.1 Current Procedure]. */
#define PV_FOR(FP) \
(((FP) != 0) \
? (((REG_AT (FP) & 0x7) == 0) ? *(PDSCDEF **)(FP) : (PDSCDEF *)(FP)) : 0)
__gcc_shell_handler (struct chf$signal_array *sig_arr,
struct chf$mech_array *mech_arr);
/* Helper for __gcc_shell_handler. Fetch the pointer to procedure currently
registered as the VMS condition handler for the live function with a frame
pointer FP. */
static ADDR
get_dyn_handler_pointer (REG fp)
/* From the frame pointer we find the procedure descriptor, and fetch
the handler_data field from there. This field contains the offset
from FP at which the address of the currently installed handler is
to be found. */
PDSCDEF * pd = PV_FOR (fp);
/* Procedure descriptor pointer for the live subprogram with FP as the frame
pointer, and to which _gcc_shell_handler is attached as a condition
handler. */
REG handler_slot_offset;
/* Offset from FP at which the address of the currently established real
condition handler is to be found. This offset is available from the
handler_data field of the procedure descriptor. */
REG handler_data_offset;
/* The handler_data field position in the procedure descriptor, which
depends on the kind of procedure at hand. */
switch (pd->pdsc$w_flags & 0xf)
case PDSC$K_KIND_FP_STACK: /* [3.4.2 PD for stack frame procedures] */
handler_data_offset = 40;
case PDSC$K_KIND_FP_REGISTER: /* [3.4.5 PD for reg frame procedures] */
handler_data_offset = 32;
handler_data_offset = 0;
/* If we couldn't determine the handler_data field position, give up. */
if (handler_data_offset == 0)
return 0;
/* Otherwise, fetch the fp offset at which the real handler address is to be
found, then fetch and return the latter in turn. */
handler_slot_offset = REG_AT ((REG)pd + handler_data_offset);
return (ADDR) REG_AT (fp + handler_slot_offset);
/* The static VMS condition handler for GCC code. Fetch the address of the
currently established condition handler, then resignal if there is none or
call the handler with the VMS condition arguments. */
__gcc_shell_handler (struct chf$signal_array *sig_arr,
struct chf$mech_array *mech_arr)
long ret;
long (*user_handler) (struct chf$signal_array *, struct chf$mech_array *);
user_handler = get_dyn_handler_pointer (mech_arr->chf$q_mch_frame);
if (!user_handler)
ret = user_handler (sig_arr, mech_arr);
return ret;