vxcrtstuff.c revision 1.1.1.1 
1/* This file is part of GCC.
2
3GCC is free software; you can redistribute it and/or modify it under
4the terms of the GNU General Public License as published by the Free
5Software Foundation; either version 3, or (at your option) any later
6version.
7
8GCC is distributed in the hope that it will be useful, but WITHOUT ANY
9WARRANTY; without even the implied warranty of MERCHANTABILITY or
10FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
11for more details.
12
13Under Section 7 of GPL version 3, you are granted additional
14permissions described in the GCC Runtime Library Exception, version
153.1, as published by the Free Software Foundation.
16
17You should have received a copy of the GNU General Public License and
18a copy of the GCC Runtime Library Exception along with this program;
19see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
20<http://www.gnu.org/licenses/>.  */
21
22/* The essential point of the crtbegin/crtend files on VxWorks is to handle
23   the eh frames registration thanks to dedicated constructors and
24   destructors.  What needs to be done depends on the VxWorks version and the
25   kind of module (rtp, dkm, ...) one is building.  */
26
27#define IN_LIBGCC2
28
29#include "auto-host.h"
30#include "tconfig.h"
31#include "tsystem.h"
32#include "coretypes.h"
33#include "tm.h"
34#include "libgcc_tm.h"
35#include "unwind-dw2-fde.h"
36
37/* If we are entitled/requested to use init/fini arrays, we'll rely on that.
38   Otherwise, we may rely on ctors/dtors sections for RTPs or expect munch to
39   be involved for kernel modules.  */
40
41#if !defined(USE_INITFINI_ARRAY) && defined(__RTP__)
42#define USE_CDTORS_SECTIONS
43#endif
44
45/*  ------------------------------ crtbegin -------------------------------  */
46
47#ifdef CRT_BEGIN
48
49/* Stick a label at the beginning of the frame unwind info so we can register
50   and deregister it with the exception handling library code.  */
51static const char __EH_FRAME_BEGIN__[]
52__attribute__((section(__LIBGCC_EH_FRAME_SECTION_NAME__), aligned(4)))
53  = { };
54
55/* Determine what names to use for the constructor/destructor functions.  */
56
57#if defined(USE_CDTORS_SECTIONS) || defined(USE_INITFINI_ARRAY)
58
59#define EH_CTOR_NAME _crtbe_register_frame
60#define EH_DTOR_NAME _ctrbe_deregister_frame
61
62#else
63
64/* No specific sections for constructors or destructors: we thus use a
65   symbol naming convention so that the constructors are then recognized
66   by munch or whatever tool is used for the final link phase.  */
67#define EH_CTOR_NAME _GLOBAL__I_00101_0__crtbe_register_frame
68#define EH_DTOR_NAME _GLOBAL__D_00101_1__crtbe_deregister_frame
69
70#endif
71
72#ifdef USE_INITFINI_ARRAY
73/* .init_array and .fini_array is supported starting VxWorks 7.2 in all
74   cases. The compiler is then configured to always support priorities in
75   constructors, so we can rely on the constructor and destructor attributes
76   to generate the proper sections.  */
77#define EH_CTOR_ATTRIBUTE __attribute__((constructor (101)))
78#define EH_DTOR_ATTRIBUTE __attribute__((destructor (101)))
79
80#else /* !USE_INITFINI_ARRAY  */
81
82/* Note: Even in case of .ctors/.dtors sections, we can't use the attribute
83   (constructor (15)) here as gcc may have been configured with constructors
84   priority disabled.  We will instead craft an explicit section name for this
85   purpose.  */
86#define EH_CTOR_ATTRIBUTE
87#define EH_DTOR_ATTRIBUTE
88
89#endif /* USE_INITFINI_ARRAY  */
90
91void EH_CTOR_NAME (void);
92void EH_DTOR_NAME (void);
93
94EH_CTOR_ATTRIBUTE void EH_CTOR_NAME (void)
95{
96  static struct object object;
97  __register_frame_info (__EH_FRAME_BEGIN__, &object);
98}
99
100EH_DTOR_ATTRIBUTE void EH_DTOR_NAME (void)
101{
102  __deregister_frame_info (__EH_FRAME_BEGIN__);
103}
104
105#ifdef USE_CDTORS_SECTIONS
106/* As explained above, we need to manually build the sections here as the
107   compiler may not have support for constructors priority enabled.  */
108static void (* volatile eh_registration_ctors[])()
109  __attribute__((section (".ctors.101")))
110= { &EH_CTOR_NAME };
111static void (* volatile eh_registration_dtors[])()
112  __attribute__((section (".dtors.65434")))
113= { &EH_DTOR_NAME };
114#endif
115
116/*  ------------------------------ crtend ---------------------------------  */
117
118#elif defined (CRT_END) /* ! CRT_BEGIN */
119
120/* Terminate the frame unwind info section with a 4byte 0 as a sentinel;
121   this would be the 'length' field in a real FDE.  */
122
123static const char __FRAME_END__[]
124     __attribute__ ((used, section(__LIBGCC_EH_FRAME_SECTION_NAME__),
125		     aligned(4)))
126  = { 0, 0, 0, 0 };
127
128#else /* ! CRT_BEGIN & ! CRT_END */
129
130#error "One of CRT_BEGIN or CRT_END must be defined."
131
132#endif
133