1 /* go-backend.c -- Go frontend interface to gcc backend.
2 Copyright (C) 2010, 2011 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
22 #include "coretypes.h"
23 #include "simple-object.h"
31 #include "common/common-target.h"
35 /* The segment name we pass to simple_object_start_read to find Go
38 #ifndef GO_EXPORT_SEGMENT_NAME
39 #define GO_EXPORT_SEGMENT_NAME "__GNU_GO"
42 /* The section name we use when reading and writing export data. */
44 #ifndef GO_EXPORT_SECTION_NAME
45 #define GO_EXPORT_SECTION_NAME ".go_export"
48 /* This file holds all the cases where the Go frontend needs
49 information from gcc's backend. */
51 /* Return the alignment in bytes of a value of type T. */
54 go_type_alignment (tree t)
56 return TYPE_ALIGN_UNIT (t);
59 /* Return the alignment in bytes of a struct field of type T. */
62 go_field_alignment (tree t)
68 #ifdef BIGGEST_FIELD_ALIGNMENT
69 if (v > BIGGEST_FIELD_ALIGNMENT)
70 v = BIGGEST_FIELD_ALIGNMENT;
73 #ifdef ADJUST_FIELD_ALIGN
75 tree field ATTRIBUTE_UNUSED;
76 field = build_decl (UNKNOWN_LOCATION, FIELD_DECL, NULL, t);
77 v = ADJUST_FIELD_ALIGN (field, v);
81 return v / BITS_PER_UNIT;
84 /* Return the size and alignment of a trampoline. */
87 go_trampoline_info (unsigned int *size, unsigned int *alignment)
89 *size = TRAMPOLINE_SIZE;
90 *alignment = TRAMPOLINE_ALIGNMENT;
93 /* This is called by the Go frontend proper if the unsafe package was
94 imported. When that happens we can not do type-based alias
98 go_imported_unsafe (void)
100 flag_strict_aliasing = false;
102 /* This is a real hack. init_varasm_once has already grabbed an
103 alias set, which we don't want when we aren't doing strict
104 aliasing. We reinitialize to make it do it again. This should
105 be OK in practice since we haven't really done anything yet. */
108 /* Let the backend know that the options have changed. */
109 targetm.override_options_after_change ();
112 /* This is called by the Go frontend proper to add data to the
113 section containing Go export data. */
116 go_write_export_data (const char *bytes, unsigned int size)
122 gcc_assert (targetm_common.have_named_sections);
123 sec = get_section (GO_EXPORT_SECTION_NAME, SECTION_DEBUG, NULL);
126 switch_to_section (sec);
127 assemble_string (bytes, size);
130 /* The go_read_export_data function is called by the Go frontend
131 proper to read Go export data from an object file. FD is a file
132 descriptor open for reading. OFFSET is the offset within the file
133 where the object file starts; this will be 0 except when reading an
134 archive. On success this returns NULL and sets *PBUF to a buffer
135 allocated using malloc, of size *PLEN, holding the export data. If
136 the data is not found, this returns NULL and sets *PBUF to NULL and
137 *PLEN to 0. If some error occurs, this returns an error message
138 and sets *PERR to an errno value or 0 if there is no relevant
142 go_read_export_data (int fd, off_t offset, char **pbuf, size_t *plen,
145 simple_object_read *sobj;
156 sobj = simple_object_start_read (fd, offset, GO_EXPORT_SEGMENT_NAME,
160 /* If we get an error here, just pretend that we didn't find any
161 export data. This is the right thing to do if the error is
162 that the file was not recognized as an object file. This
163 will ignore file I/O errors, but it's not too big a deal
164 because we will wind up giving some other error later. */
168 found = simple_object_find_section (sobj, GO_EXPORT_SECTION_NAME,
169 &sec_offset, &sec_length,
171 simple_object_release_read (sobj);
175 if (lseek (fd, offset + sec_offset, SEEK_SET) < 0)
178 return _("lseek failed while reading export data");
181 buf = XNEWVEC (char, sec_length);
185 return _("memory allocation failed while reading export data");
188 c = read (fd, buf, sec_length);
193 return _("read failed while reading export data");
199 return _("short read while reading export data");