1/* go-backend.c -- Go frontend interface to gcc backend. 2 Copyright (C) 2010-2015 Free Software Foundation, Inc. 3 4This file is part of GCC. 5 6GCC is free software; you can redistribute it and/or modify it under 7the terms of the GNU General Public License as published by the Free 8Software Foundation; either version 3, or (at your option) any later 9version. 10 11GCC is distributed in the hope that it will be useful, but WITHOUT ANY 12WARRANTY; without even the implied warranty of MERCHANTABILITY or 13FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14for more details. 15 16You should have received a copy of the GNU General Public License 17along with GCC; see the file COPYING3. If not see 18<http://www.gnu.org/licenses/>. */ 19 20#include "config.h" 21#include "system.h" 22#include "coretypes.h" 23#include "simple-object.h" 24#include "tm.h" 25#include "hash-set.h" 26#include "machmode.h" 27#include "vec.h" 28#include "double-int.h" 29#include "input.h" 30#include "alias.h" 31#include "symtab.h" 32#include "wide-int.h" 33#include "inchash.h" 34#include "tree.h" 35#include "stor-layout.h" 36#include "tm_p.h" 37#include "intl.h" 38#include "output.h" /* for assemble_string */ 39#include "target.h" 40#include "common/common-target.h" 41#include "diagnostic.h" 42 43#include "go-c.h" 44 45/* The segment name we pass to simple_object_start_read to find Go 46 export data. */ 47 48#ifndef GO_EXPORT_SEGMENT_NAME 49#define GO_EXPORT_SEGMENT_NAME "__GNU_GO" 50#endif 51 52/* The section name we use when reading and writing export data. */ 53 54#ifndef GO_EXPORT_SECTION_NAME 55#define GO_EXPORT_SECTION_NAME ".go_export" 56#endif 57 58/* This file holds all the cases where the Go frontend needs 59 information from gcc's backend. */ 60 61/* Return whether or not GCC has reported any errors. */ 62 63bool 64saw_errors (void) 65{ 66 return errorcount != 0 || sorrycount != 0; 67} 68 69/* Return the alignment in bytes of a struct field of type T. */ 70 71unsigned int 72go_field_alignment (tree t) 73{ 74 unsigned int v; 75 76 v = TYPE_ALIGN (t); 77 78#ifdef BIGGEST_FIELD_ALIGNMENT 79 if (v > BIGGEST_FIELD_ALIGNMENT) 80 v = BIGGEST_FIELD_ALIGNMENT; 81#endif 82 83#ifdef ADJUST_FIELD_ALIGN 84 { 85 tree field ATTRIBUTE_UNUSED; 86 field = build_decl (UNKNOWN_LOCATION, FIELD_DECL, NULL, t); 87 v = ADJUST_FIELD_ALIGN (field, v); 88 } 89#endif 90 91 return v / BITS_PER_UNIT; 92} 93 94/* Return the size and alignment of a trampoline. */ 95 96void 97go_trampoline_info (unsigned int *size, unsigned int *alignment) 98{ 99 *size = TRAMPOLINE_SIZE; 100 *alignment = TRAMPOLINE_ALIGNMENT; 101} 102 103/* This is called by the Go frontend proper if the unsafe package was 104 imported. When that happens we can not do type-based alias 105 analysis. */ 106 107void 108go_imported_unsafe (void) 109{ 110 flag_strict_aliasing = false; 111 112 /* Let the backend know that the options have changed. */ 113 targetm.override_options_after_change (); 114} 115 116/* This is called by the Go frontend proper to add data to the 117 section containing Go export data. */ 118 119void 120go_write_export_data (const char *bytes, unsigned int size) 121{ 122 static section* sec; 123 124 if (sec == NULL) 125 { 126 gcc_assert (targetm_common.have_named_sections); 127 sec = get_section (GO_EXPORT_SECTION_NAME, SECTION_DEBUG, NULL); 128 } 129 130 switch_to_section (sec); 131 assemble_string (bytes, size); 132} 133 134/* The go_read_export_data function is called by the Go frontend 135 proper to read Go export data from an object file. FD is a file 136 descriptor open for reading. OFFSET is the offset within the file 137 where the object file starts; this will be 0 except when reading an 138 archive. On success this returns NULL and sets *PBUF to a buffer 139 allocated using malloc, of size *PLEN, holding the export data. If 140 the data is not found, this returns NULL and sets *PBUF to NULL and 141 *PLEN to 0. If some error occurs, this returns an error message 142 and sets *PERR to an errno value or 0 if there is no relevant 143 errno. */ 144 145const char * 146go_read_export_data (int fd, off_t offset, char **pbuf, size_t *plen, 147 int *perr) 148{ 149 simple_object_read *sobj; 150 const char *errmsg; 151 off_t sec_offset; 152 off_t sec_length; 153 int found; 154 char *buf; 155 ssize_t c; 156 157 *pbuf = NULL; 158 *plen = 0; 159 160 sobj = simple_object_start_read (fd, offset, GO_EXPORT_SEGMENT_NAME, 161 &errmsg, perr); 162 if (sobj == NULL) 163 { 164 /* If we get an error here, just pretend that we didn't find any 165 export data. This is the right thing to do if the error is 166 that the file was not recognized as an object file. This 167 will ignore file I/O errors, but it's not too big a deal 168 because we will wind up giving some other error later. */ 169 return NULL; 170 } 171 172 found = simple_object_find_section (sobj, GO_EXPORT_SECTION_NAME, 173 &sec_offset, &sec_length, 174 &errmsg, perr); 175 simple_object_release_read (sobj); 176 if (!found) 177 return errmsg; 178 179 if (lseek (fd, offset + sec_offset, SEEK_SET) < 0) 180 { 181 *perr = errno; 182 return _("lseek failed while reading export data"); 183 } 184 185 buf = XNEWVEC (char, sec_length); 186 if (buf == NULL) 187 { 188 *perr = errno; 189 return _("memory allocation failed while reading export data"); 190 } 191 192 c = read (fd, buf, sec_length); 193 if (c < 0) 194 { 195 *perr = errno; 196 free (buf); 197 return _("read failed while reading export data"); 198 } 199 200 if (c < sec_length) 201 { 202 free (buf); 203 return _("short read while reading export data"); 204 } 205 206 *pbuf = buf; 207 *plen = sec_length; 208 209 return NULL; 210} 211