# This shell script emits a C file. -*- C -*- # It does some substitutions. cat >e${EMULATION_NAME}.c < ELF support by Ian Lance Taylor This file is part of GLD, the Gnu Linker. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #define TARGET_IS_${EMULATION_NAME} #include "bfd.h" #include "sysdep.h" #include #include "bfdlink.h" #include "ld.h" #include "config.h" #include "ldmain.h" #include "ldemul.h" #include "ldfile.h" #include "ldmisc.h" #include "ldexp.h" #include "ldlang.h" #include "ldgram.h" static void gld${EMULATION_NAME}_before_parse PARAMS ((void)); static boolean gld${EMULATION_NAME}_open_dynamic_archive PARAMS ((const char *, lang_input_statement_type *)); static void gld${EMULATION_NAME}_after_open PARAMS ((void)); static void gld${EMULATION_NAME}_check_needed PARAMS ((lang_input_statement_type *)); static boolean gld${EMULATION_NAME}_search_needed PARAMS ((const char *, const char *)); static boolean gld${EMULATION_NAME}_try_needed PARAMS ((const char *)); static void gld${EMULATION_NAME}_before_allocation PARAMS ((void)); static void gld${EMULATION_NAME}_find_statement_assignment PARAMS ((lang_statement_union_type *)); static void gld${EMULATION_NAME}_find_exp_assignment PARAMS ((etree_type *)); static boolean gld${EMULATION_NAME}_place_orphan PARAMS ((lang_input_statement_type *, asection *)); static void gld${EMULATION_NAME}_place_section PARAMS ((lang_statement_union_type *)); static char *gld${EMULATION_NAME}_get_script PARAMS ((int *isfile)); static void gld${EMULATION_NAME}_before_parse() { ldfile_output_architecture = bfd_arch_${ARCH}; config.dynamic_link = ${DYNAMIC_LINK-true}; } /* Try to open a dynamic archive. This is where we know that ELF dynamic libraries have an extension of .so. */ static boolean gld${EMULATION_NAME}_open_dynamic_archive (arch, entry) const char *arch; lang_input_statement_type *entry; { const char *filename; filename = entry->filename; if (! ldfile_open_file_search (arch, entry, "lib", ".so")) return false; /* We have found a dynamic object to include in the link. The ELF backend linker will create a DT_NEEDED entry in the .dynamic section naming this file. If this file includes a DT_SONAME entry, it will be used. Otherwise, the ELF linker will just use the name of the file. For an archive found by searching, like this one, the DT_NEEDED entry should consist of just the name of the file, without the path information used to find it. Note that we only need to do this if we have a dynamic object; an archive will never be referenced by a DT_NEEDED entry. FIXME: This approach--using bfd_elf_set_dt_needed_name--is not very pretty. I haven't been able to think of anything that is pretty, though. */ if (bfd_check_format (entry->the_bfd, bfd_object) && (entry->the_bfd->flags & DYNAMIC) != 0) { char *needed_name; ASSERT (entry->is_archive && entry->search_dirs_flag); needed_name = (char *) xmalloc (strlen (filename) + strlen (arch) + sizeof "lib.so"); sprintf (needed_name, "lib%s%s.so", filename, arch); bfd_elf_set_dt_needed_name (entry->the_bfd, needed_name); } return true; } /* These variables are required to pass information back and forth between after_open and check_needed. */ static struct bfd_elf_link_needed_list *global_needed; static boolean global_found; /* This is called after all the input files have been opened. */ static void gld${EMULATION_NAME}_after_open () { struct bfd_elf_link_needed_list *needed, *l; /* Get the list of files which appear in DT_NEEDED entries in dynamic objects included in the link (often there will be none). For each such file, we want to track down the corresponding library, and include the symbol table in the link. This is what the runtime dynamic linker will do. Tracking the files down here permits one dynamic object to include another without requiring special action by the person doing the link. Note that the needed list can actually grow while we are stepping through this loop. */ needed = bfd_elf_get_needed_list (output_bfd, &link_info); for (l = needed; l != NULL; l = l->next) { struct bfd_elf_link_needed_list *ll; const char *lib_path; size_t len; search_dirs_type *search; /* If we've already seen this file, skip it. */ for (ll = needed; ll != l; ll = ll->next) if (strcmp (ll->name, l->name) == 0) break; if (ll != l) continue; /* See if this file was included in the link explicitly. */ global_needed = l; global_found = false; lang_for_each_input_file (gld${EMULATION_NAME}_check_needed); if (global_found) continue; /* We need to find this file and include the symbol table. We want to search for the file in the same way that the dynamic linker will search. That means that we want to use rpath, then the environment variable LD_LIBRARY_PATH, then the linker script LIB_SEARCH_DIRS. We do not search using the -L arguments. */ if (gld${EMULATION_NAME}_search_needed (command_line.rpath, l->name)) continue; lib_path = (const char *) getenv ("LD_LIBRARY_PATH"); if (gld${EMULATION_NAME}_search_needed (lib_path, l->name)) continue; len = strlen (l->name); for (search = search_head; search != NULL; search = search->next) { char *filename; if (search->cmdline) continue; filename = (char *) xmalloc (strlen (search->name) + len + 2); sprintf (filename, "%s/%s", search->name, l->name); if (gld${EMULATION_NAME}_try_needed (filename)) break; free (filename); } if (search != NULL) continue; einfo ("%P: warning: %s, needed by %B, not found\n", l->name, l->by); } } /* Search for a needed file in a path. */ static boolean gld${EMULATION_NAME}_search_needed (path, name) const char *path; const char *name; { const char *s; size_t len; if (path == NULL || *path == '\0') return false; len = strlen (name); while (1) { char *filename, *sset; s = strchr (path, ':'); if (s == NULL) s = path + strlen (path); filename = (char *) xmalloc (s - path + len + 2); if (s == path) sset = filename; else { memcpy (filename, path, s - path); filename[s - path] = '/'; sset = filename + (s - path) + 1; } strcpy (sset, name); if (gld${EMULATION_NAME}_try_needed (filename)) return true; free (filename); if (*s == '\0') break; path = s + 1; } return false; } /* This function is called for each possible name for a dynamic object named by a DT_NEEDED entry. */ static boolean gld${EMULATION_NAME}_try_needed (name) const char *name; { bfd *abfd; abfd = bfd_openr (name, bfd_get_target (output_bfd)); if (abfd == NULL) return false; if (! bfd_check_format (abfd, bfd_object)) { (void) bfd_close (abfd); return false; } if ((bfd_get_file_flags (abfd) & DYNAMIC) == 0) { (void) bfd_close (abfd); return false; } /* We've found a dynamic object matching the DT_NEEDED entry. */ /* Tell the ELF backend that don't want the output file to have a DT_NEEDED entry for this file. */ bfd_elf_set_dt_needed_name (abfd, ""); /* Add this file into the symbol table. */ if (! bfd_link_add_symbols (abfd, &link_info)) einfo ("%F%B: could not read symbols: %E\n", abfd); return true; } /* See if an input file matches a DT_NEEDED entry. */ static void gld${EMULATION_NAME}_check_needed (s) lang_input_statement_type *s; { if (s->filename != NULL && strcmp (s->filename, global_needed->name) == 0) global_found = true; } /* This is called after the sections have been attached to output sections, but before any sizes or addresses have been set. */ static void gld${EMULATION_NAME}_before_allocation () { asection *sinterp; /* If we are going to make any variable assignments, we need to let the ELF backend know about them in case the variables are referred to by dynamic objects. */ lang_for_each_statement (gld${EMULATION_NAME}_find_statement_assignment); /* Let the ELF backend work out the sizes of any sections required by dynamic linking. */ if (! bfd_elf32_size_dynamic_sections (output_bfd, command_line.soname, command_line.rpath, command_line.export_dynamic, &link_info, &sinterp)) einfo ("%P%F: failed to set dynamic section sizes: %E\n"); /* Let the user override the dynamic linker we are using. */ if (command_line.interpreter != NULL && sinterp != NULL) { sinterp->contents = (bfd_byte *) command_line.interpreter; sinterp->_raw_size = strlen (command_line.interpreter) + 1; } /* Look for any sections named .gnu.warning. As a GNU extensions, we treat such sections as containing warning messages. We print out the warning message, and then zero out the section size so that it does not get copied into the output file. */ { LANG_FOR_EACH_INPUT_STATEMENT (is) { asection *s; bfd_size_type sz; char *msg; boolean ret; if (is->just_syms_flag) continue; s = bfd_get_section_by_name (is->the_bfd, ".gnu.warning"); if (s == NULL) continue; sz = bfd_section_size (is->the_bfd, s); msg = xmalloc ((size_t) sz + 1); if (! bfd_get_section_contents (is->the_bfd, s, msg, (file_ptr) 0, sz)) einfo ("%F%B: Can't read contents of section .gnu.warning: %E\n", is->the_bfd); msg[sz] = '\0'; ret = link_info.callbacks->warning (&link_info, msg); ASSERT (ret); free (msg); /* Clobber the section size, so that we don't waste copying the warning into the output file. */ s->_raw_size = 0; } } #if defined (TARGET_IS_elf32bmip) || defined (TARGET_IS_elf32lmip) /* For MIPS ELF the .reginfo section requires special handling. Each input section is 24 bytes, and the final output section must also be 24 bytes. We handle this by clobbering all but the first input section size to 0. The .reginfo section is handled specially by the backend code anyhow. */ { boolean found = false; LANG_FOR_EACH_INPUT_STATEMENT (is) { asection *s; if (is->just_syms_flag) continue; s = bfd_get_section_by_name (is->the_bfd, ".reginfo"); if (s == NULL) continue; if (! found) { found = true; continue; } s->_raw_size = 0; s->_cooked_size = 0; } } #endif } /* This is called by the before_allocation routine via lang_for_each_statement. It locates any assignment statements, and tells the ELF backend about them, in case they are assignments to symbols which are referred to by dynamic objects. */ static void gld${EMULATION_NAME}_find_statement_assignment (s) lang_statement_union_type *s; { if (s->header.type == lang_assignment_statement_enum) gld${EMULATION_NAME}_find_exp_assignment (s->assignment_statement.exp); } /* Look through an expression for an assignment statement. */ static void gld${EMULATION_NAME}_find_exp_assignment (exp) etree_type *exp; { struct bfd_link_hash_entry *h; switch (exp->type.node_class) { case etree_provide: h = bfd_link_hash_lookup (link_info.hash, exp->assign.dst, false, false, false); if (h == NULL) break; /* We call record_link_assignment even if the symbol is defined. This is because if it is defined by a dynamic object, we actually want to use the value defined by the linker script, not the value from the dynamic object (because we are setting symbols like etext). If the symbol is defined by a regular object, then, as it happens, calling record_link_assignment will do no harm. */ /* Fall through. */ case etree_assign: if (strcmp (exp->assign.dst, ".") != 0) { if (! (bfd_elf32_record_link_assignment (output_bfd, &link_info, exp->assign.dst, exp->type.node_class == etree_provide ? true : false))) einfo ("%P%F: failed to record assignment to %s: %E\n", exp->assign.dst); } gld${EMULATION_NAME}_find_exp_assignment (exp->assign.src); break; case etree_binary: gld${EMULATION_NAME}_find_exp_assignment (exp->binary.lhs); gld${EMULATION_NAME}_find_exp_assignment (exp->binary.rhs); break; case etree_trinary: gld${EMULATION_NAME}_find_exp_assignment (exp->trinary.lhs); gld${EMULATION_NAME}_find_exp_assignment (exp->trinary.lhs); gld${EMULATION_NAME}_find_exp_assignment (exp->trinary.rhs); break; case etree_unary: gld${EMULATION_NAME}_find_exp_assignment (exp->unary.child); break; default: break; } } /* Place an orphan section. We use this to put random SHF_ALLOC sections in the right segment. */ static asection *hold_section; static lang_output_section_statement_type *hold_use; static lang_output_section_statement_type *hold_text; static lang_output_section_statement_type *hold_data; static lang_output_section_statement_type *hold_bss; static lang_output_section_statement_type *hold_rel; /*ARGSUSED*/ static boolean gld${EMULATION_NAME}_place_orphan (file, s) lang_input_statement_type *file; asection *s; { lang_output_section_statement_type *place; asection *snew, **pps; lang_statement_list_type *old; lang_statement_list_type add; etree_type *address; const char *secname, *ps; lang_output_section_statement_type *os; if ((s->flags & SEC_ALLOC) == 0) return false; /* Look through the script to see where to place this section. */ hold_section = s; hold_use = NULL; lang_for_each_statement (gld${EMULATION_NAME}_place_section); if (hold_use != NULL) { /* We have already placed a section with this name. */ wild_doit (&hold_use->children, s, hold_use, file); return true; } secname = bfd_get_section_name (s->owner, s); /* Decide which segment the section should go in based on the section name and section flags. */ place = NULL; if ((s->flags & SEC_HAS_CONTENTS) == 0 && hold_bss != NULL) place = hold_bss; else if ((s->flags & SEC_READONLY) == 0 && hold_data != NULL) place = hold_data; else if (strncmp (secname, ".rel", 4) == 0 && hold_rel != NULL) place = hold_rel; else if ((s->flags & SEC_READONLY) != 0 && hold_text != NULL) place = hold_text; if (place == NULL) return false; /* Create the section in the output file, and put it in the right place. This shuffling is to make the output file look neater. */ snew = bfd_make_section (output_bfd, secname); if (snew == NULL) einfo ("%P%F: output format %s cannot represent section called %s\n", output_bfd->xvec->name, secname); if (place->bfd_section != NULL) { for (pps = &output_bfd->sections; *pps != snew; pps = &(*pps)->next) ; *pps = snew->next; snew->next = place->bfd_section->next; place->bfd_section->next = snew; } /* Start building a list of statements for this section. */ old = stat_ptr; stat_ptr = &add; lang_list_init (stat_ptr); /* If the name of the section is representable in C, then create symbols to mark the start and the end of the section. */ for (ps = secname; *ps != '\0'; ps++) if (! isalnum (*ps) && *ps != '_') break; if (*ps == '\0' && config.build_constructors) { char *symname; symname = (char *) xmalloc (ps - secname + sizeof "__start_"); sprintf (symname, "__start_%s", secname); lang_add_assignment (exp_assop ('=', symname, exp_nameop (NAME, "."))); } if (! link_info.relocateable) address = NULL; else address = exp_intop ((bfd_vma) 0); lang_enter_output_section_statement (secname, address, 0, (bfd_vma) 0, (etree_type *) NULL, (etree_type *) NULL, (etree_type *) NULL); os = lang_output_section_statement_lookup (secname); wild_doit (&os->children, s, os, file); lang_leave_output_section_statement ((bfd_vma) 0, "*default*"); stat_ptr = &add; if (*ps == '\0' && config.build_constructors) { char *symname; symname = (char *) xmalloc (ps - secname + sizeof "__stop_"); sprintf (symname, "__stop_%s", secname); lang_add_assignment (exp_assop ('=', symname, exp_nameop (NAME, "."))); } /* Now stick the new statement list right after PLACE. */ *add.tail = place->header.next; place->header.next = add.head; stat_ptr = old; return true; } static void gld${EMULATION_NAME}_place_section (s) lang_statement_union_type *s; { lang_output_section_statement_type *os; if (s->header.type != lang_output_section_statement_enum) return; os = &s->output_section_statement; if (strcmp (os->name, hold_section->name) == 0) hold_use = os; if (strcmp (os->name, ".text") == 0) hold_text = os; else if (strcmp (os->name, ".data") == 0) hold_data = os; else if (strcmp (os->name, ".bss") == 0) hold_bss = os; else if (hold_rel == NULL && strncmp (os->name, ".rel", 4) == 0) hold_rel = os; } static char * gld${EMULATION_NAME}_get_script(isfile) int *isfile; EOF if test -n "$COMPILE_IN" then # Scripts compiled in. # sed commands to quote an ld script as a C string. sc='s/["\\]/\\&/g s/$/\\n\\/ 1s/^/"/ $s/$/n"/ ' cat >>e${EMULATION_NAME}.c <>e${EMULATION_NAME}.c <>e${EMULATION_NAME}.c <