1 /* Static condition handler for Alpha/VMS.
2 Copyright (C) 2005-2022 Free Software Foundation, Inc.
3
4 This file is part of GCC.
5
6 GCC is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published
8 by the Free Software Foundation; either version 3, or (at your
9 option) any later version.
10
11 GCC is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
14 License for more details.
15
16 Under Section 7 of GPL version 3, you are granted additional
17 permissions described in the GCC Runtime Library Exception, version
18 3.1, as published by the Free Software Foundation.
19
20 You should have received a copy of the GNU General Public License and
21 a copy of the GCC Runtime Library Exception along with this program;
22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 <http://www.gnu.org/licenses/>. */
24
25 /* This file implements __gcc_shell_handler, the static VMS condition handler
26 used as the indirection wrapper around user level handlers installed with
27 establish_vms_condition_handler GCC builtin.
28
29 [ABI] in comments refers to the "HP OpenVMS calling standard" document
30 dated January 2005. */
31
32 #include <vms/chfdef.h>
33 #include <vms/pdscdef.h>
34 #include <vms/ssdef.h>
35
36 typedef void * ADDR;
37 typedef unsigned long long REG;
38
39 #define REG_AT(addr) (*(REG *)(addr))
40
41 /* Compute pointer to procedure descriptor (Procedure Value) from Frame
42 Pointer FP, according to the rules in [ABI-3.5.1 Current Procedure]. */
43 #define PV_FOR(FP) \
44 (((FP) != 0) \
45 ? (((REG_AT (FP) & 0x7) == 0) ? *(PDSCDEF **)(FP) : (PDSCDEF *)(FP)) : 0)
46
47 long
48 __gcc_shell_handler (struct chf$signal_array *sig_arr,
49 struct chf$mech_array *mech_arr);
50
51 /* Helper for __gcc_shell_handler. Fetch the pointer to procedure currently
52 registered as the VMS condition handler for the live function with a frame
53 pointer FP. */
54
55 static ADDR
get_dyn_handler_pointer(REG fp)56 get_dyn_handler_pointer (REG fp)
57 {
58 /* From the frame pointer we find the procedure descriptor, and fetch
59 the handler_data field from there. This field contains the offset
60 from FP at which the address of the currently installed handler is
61 to be found. */
62
63 PDSCDEF * pd = PV_FOR (fp);
64 /* Procedure descriptor pointer for the live subprogram with FP as the frame
65 pointer, and to which _gcc_shell_handler is attached as a condition
66 handler. */
67
68 REG handler_slot_offset;
69 /* Offset from FP at which the address of the currently established real
70 condition handler is to be found. This offset is available from the
71 handler_data field of the procedure descriptor. */
72
73 REG handler_data_offset;
74 /* The handler_data field position in the procedure descriptor, which
75 depends on the kind of procedure at hand. */
76
77 switch (pd->pdsc$w_flags & 0xf)
78 {
79 case PDSC$K_KIND_FP_STACK: /* [3.4.2 PD for stack frame procedures] */
80 handler_data_offset = 40;
81 break;
82
83 case PDSC$K_KIND_FP_REGISTER: /* [3.4.5 PD for reg frame procedures] */
84 handler_data_offset = 32;
85 break;
86
87 default:
88 handler_data_offset = 0;
89 break;
90 }
91
92 /* If we couldn't determine the handler_data field position, give up. */
93 if (handler_data_offset == 0)
94 return 0;
95
96 /* Otherwise, fetch the fp offset at which the real handler address is to be
97 found, then fetch and return the latter in turn. */
98
99 handler_slot_offset = REG_AT ((REG)pd + handler_data_offset);
100
101 return (ADDR) REG_AT (fp + handler_slot_offset);
102 }
103
104 /* The static VMS condition handler for GCC code. Fetch the address of the
105 currently established condition handler, then resignal if there is none or
106 call the handler with the VMS condition arguments. */
107
108 long
__gcc_shell_handler(struct chf$signal_array * sig_arr,struct chf$mech_array * mech_arr)109 __gcc_shell_handler (struct chf$signal_array *sig_arr,
110 struct chf$mech_array *mech_arr)
111 {
112 long ret;
113 long (*user_handler) (struct chf$signal_array *, struct chf$mech_array *);
114
115 user_handler = get_dyn_handler_pointer (mech_arr->chf$q_mch_frame);
116 if (!user_handler)
117 ret = SS$_RESIGNAL;
118 else
119 ret = user_handler (sig_arr, mech_arr);
120
121 return ret;
122 }
123
124