/* linker.c -- BFD linker routines Copyright (C) 1993, 94 Free Software Foundation, Inc. Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support This file is part of BFD, the Binary File Descriptor library. 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., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include "bfd.h" #include "sysdep.h" #include "libbfd.h" #include "bfdlink.h" #include "genlink.h" /* SECTION Linker Functions @cindex Linker The linker uses three special entry points in the BFD target vector. It is not necessary to write special routines for these entry points when creating a new BFD back end, since generic versions are provided. However, writing them can speed up linking and make it use significantly less runtime memory. The first routine creates a hash table used by the other routines. The second routine adds the symbols from an object file to the hash table. The third routine takes all the object files and links them together to create the output file. These routines are designed so that the linker proper does not need to know anything about the symbols in the object files that it is linking. The linker merely arranges the sections as directed by the linker script and lets BFD handle the details of symbols and relocs. The second routine and third routines are passed a pointer to a <> structure (defined in <>) which holds information relevant to the link, including the linker hash table (which was created by the first routine) and a set of callback functions to the linker proper. The generic linker routines are in <>, and use the header file <>. As of this writing, the only back ends which have implemented versions of these routines are a.out (in <>) and ECOFF (in <>). The a.out routines are used as examples throughout this section. @menu @* Creating a Linker Hash Table:: @* Adding Symbols to the Hash Table:: @* Performing the Final Link:: @end menu INODE Creating a Linker Hash Table, Adding Symbols to the Hash Table, Linker Functions, Linker Functions SUBSECTION Creating a linker hash table @cindex _bfd_link_hash_table_create in target vector @cindex target vector (_bfd_link_hash_table_create) The linker routines must create a hash table, which must be derived from <> described in <>. @xref{Hash Tables} for information on how to create a derived hash table. This entry point is called using the target vector of the linker output file. The <<_bfd_link_hash_table_create>> entry point must allocate and initialize an instance of the desired hash table. If the back end does not require any additional information to be stored with the entries in the hash table, the entry point may simply create a <>. Most likely, however, some additional information will be needed. For example, with each entry in the hash table the a.out linker keeps the index the symbol has in the final output file (this index number is used so that when doing a relocateable link the symbol index used in the output file can be quickly filled in when copying over a reloc). The a.out linker code defines the required structures and functions for a hash table derived from <>. The a.out linker hash table is created by the function <>; it simply allocates space for the hash table, initializes it, and returns a pointer to it. When writing the linker routines for a new back end, you will generally not know exactly which fields will be required until you have finished. You should simply create a new hash table which defines no additional fields, and then simply add fields as they become necessary. INODE Adding Symbols to the Hash Table, Performing the Final Link, Creating a Linker Hash Table, Linker Functions SUBSECTION Adding symbols to the hash table @cindex _bfd_link_add_symbols in target vector @cindex target vector (_bfd_link_add_symbols) The linker proper will call the <<_bfd_link_add_symbols>> entry point for each object file or archive which is to be linked (typically these are the files named on the command line, but some may also come from the linker script). The entry point is responsible for examining the file. For an object file, BFD must add any relevant symbol information to the hash table. For an archive, BFD must determine which elements of the archive should be used and adding them to the link. The a.out version of this entry point is <>. @menu @* Differing file formats:: @* Adding symbols from an object file:: @* Adding symbols from an archive:: @end menu INODE Differing file formats, Adding symbols from an object file, Adding Symbols to the Hash Table, Adding Symbols to the Hash Table SUBSUBSECTION Differing file formats Normally all the files involved in a link will be of the same format, but it is also possible to link together different format object files, and the back end must support that. The <<_bfd_link_add_symbols>> entry point is called via the target vector of the file to be added. This has an important consequence: the function may not assume that the hash table is the type created by the corresponding <<_bfd_link_hash_table_create>> vector. All the <<_bfd_link_add_symbols>> function can assume about the hash table is that it is derived from <>. Sometimes the <<_bfd_link_add_symbols>> function must store some information in the hash table entry to be used by the <<_bfd_final_link>> function. In such a case the <> field of the hash table must be checked to make sure that the hash table was created by an object file of the same format. The <<_bfd_final_link>> routine must be prepared to handle a hash entry without any extra information added by the <<_bfd_link_add_symbols>> function. A hash entry without extra information will also occur when the linker script directs the linker to create a symbol. Note that, regardless of how a hash table entry is added, all the fields will be initialized to some sort of null value by the hash table entry initialization function. See <> for an example of how to check the <> field before saving information (in this case, the ECOFF external symbol debugging information) in a hash table entry. INODE Adding symbols from an object file, Adding symbols from an archive, Differing file formats, Adding Symbols to the Hash Table SUBSUBSECTION Adding symbols from an object file When the <<_bfd_link_add_symbols>> routine is passed an object file, it must add all externally visible symbols in that object file to the hash table. The actual work of adding the symbol to the hash table is normally handled by the function <<_bfd_generic_link_add_one_symbol>>. The <<_bfd_link_add_symbols>> routine is responsible for reading all the symbols from the object file and passing the correct information to <<_bfd_generic_link_add_one_symbol>>. The <<_bfd_link_add_symbols>> routine should not use <> to read the symbols. The point of providing this routine is to avoid the overhead of converting the symbols into generic <> structures. @findex _bfd_generic_link_add_one_symbol <<_bfd_generic_link_add_one_symbol>> handles the details of combining common symbols, warning about multiple definitions, and so forth. It takes arguments which describe the symbol to add, notably symbol flags, a section, and an offset. The symbol flags include such things as <> or <>. The section is a section in the object file, or something like <> for an undefined symbol or <> for a common symbol. If the <<_bfd_final_link>> routine is also going to need to read the symbol information, the <<_bfd_link_add_symbols>> routine should save it somewhere attached to the object file BFD. However, the information should only be saved if the <> field of the <> argument is true, so that the <<-no-keep-memory>> linker switch is effective. The a.out function which adds symbols from an object file is <>, and most of the interesting work is in <>. The latter saves pointers to the hash tables entries created by <<_bfd_generic_link_add_one_symbol>> indexed by symbol number, so that the <<_bfd_final_link>> routine does not have to call the hash table lookup routine to locate the entry. INODE Adding symbols from an archive, , Adding symbols from an object file, Adding Symbols to the Hash Table SUBSUBSECTION Adding symbols from an archive When the <<_bfd_link_add_symbols>> routine is passed an archive, it must look through the symbols defined by the archive and decide which elements of the archive should be included in the link. For each such element it must call the <> linker callback, and it must add the symbols from the object file to the linker hash table. @findex _bfd_generic_link_add_archive_symbols In most cases the work of looking through the symbols in the archive should be done by the <<_bfd_generic_link_add_archive_symbols>> function. This function builds a hash table from the archive symbol table and looks through the list of undefined symbols to see which elements should be included. <<_bfd_generic_link_add_archive_symbols>> is passed a function to call to make the final decision about adding an archive element to the link and to do the actual work of adding the symbols to the linker hash table. The function passed to <<_bfd_generic_link_add_archive_symbols>> must read the symbols of the archive element and decide whether the archive element should be included in the link. If the element is to be included, the <> linker callback routine must be called with the element as an argument, and the elements symbols must be added to the linker hash table just as though the element had itself been passed to the <<_bfd_link_add_symbols>> function. When the a.out <<_bfd_link_add_symbols>> function receives an archive, it calls <<_bfd_generic_link_add_archive_symbols>> passing <> as the function argument. <> calls <>. If the latter decides to add the element (an element is only added if it provides a real, non-common, definition for a previously undefined or common symbol) it calls the <> callback and then <> calls <> to actually add the symbols to the linker hash table. The ECOFF back end is unusual in that it does not normally call <<_bfd_generic_link_add_archive_symbols>>, because ECOFF archives already contain a hash table of symbols. The ECOFF back end searches the archive itself to avoid the overhead of creating a new hash table. INODE Performing the Final Link, , Adding Symbols to the Hash Table, Linker Functions SUBSECTION Performing the final link @cindex _bfd_link_final_link in target vector @cindex target vector (_bfd_final_link) When all the input files have been processed, the linker calls the <<_bfd_final_link>> entry point of the output BFD. This routine is responsible for producing the final output file, which has several aspects. It must relocate the contents of the input sections and copy the data into the output sections. It must build an output symbol table including any local symbols from the input files and the global symbols from the hash table. When producing relocateable output, it must modify the input relocs and write them into the output file. There may also be object format dependent work to be done. The linker will also call the <> entry point when the BFD is closed. The two entry points must work together in order to produce the correct output file. The details of how this works are inevitably dependent upon the specific object file format. The a.out <<_bfd_final_link>> routine is <>. @menu @* Information provided by the linker:: @* Relocating the section contents:: @* Writing the symbol table:: @end menu INODE Information provided by the linker, Relocating the section contents, Performing the Final Link, Performing the Final Link SUBSUBSECTION Information provided by the linker Before the linker calls the <<_bfd_final_link>> entry point, it sets up some data structures for the function to use. The <> field of the <> structure will point to a list of all the input files included in the link. These files are linked through the <> field of the <> structure. Each section in the output file will have a list of <> structures attached to the <> field (the <> structure is defined in <>). These structures describe how to create the contents of the output section in terms of the contents of various input sections, fill constants, and, eventually, other types of information. They also describe relocs that must be created by the BFD backend, but do not correspond to any input file; this is used to support -Ur, which builds constructors while generating a relocateable object file. INODE Relocating the section contents, Writing the symbol table, Information provided by the linker, Performing the Final Link SUBSUBSECTION Relocating the section contents The <<_bfd_final_link>> function should look through the <> structures attached to each section of the output file. Each <> structure should either be handled specially, or it should be passed to the function <<_bfd_default_link_order>> which will do the right thing (<<_bfd_default_link_order>> is defined in <>). For efficiency, a <> of type <> whose associated section belongs to a BFD of the same format as the output BFD must be handled specially. This type of <> describes part of an output section in terms of a section belonging to one of the input files. The <<_bfd_final_link>> function should read the contents of the section and any associated relocs, apply the relocs to the section contents, and write out the modified section contents. If performing a relocateable link, the relocs themselves must also be modified and written out. @findex _bfd_relocate_contents @findex _bfd_final_link_relocate The functions <<_bfd_relocate_contents>> and <<_bfd_final_link_relocate>> provide some general support for performing the actual relocations, notably overflow checking. Their arguments include information about the symbol the relocation is against and a <> argument which describes the relocation to perform. These functions are defined in <>. The a.out function which handles reading, relocating, and writing section contents is <>. The actual relocation is done in <> and <>. INODE Writing the symbol table, , Relocating the section contents, Performing the Final Link SUBSUBSECTION Writing the symbol table The <<_bfd_final_link>> function must gather all the symbols in the input files and write them out. It must also write out all the symbols in the global hash table. This must be controlled by the <> and <> fields of the <> structure. The local symbols of the input files will not have been entered into the linker hash table. The <<_bfd_final_link>> routine must consider each input file and include the symbols in the output file. It may be convenient to do this when looking through the <> structures, or it may be done by stepping through the <> list. The <<_bfd_final_link>> routine must also traverse the global hash table to gather all the externally visible symbols. It is possible that most of the externally visible symbols may be written out when considering the symbols of each input file, but it is still necessary to traverse the hash table since the linker script may have defined some symbols that are not in any of the input files. The <> field in the <> structure may be used to determine which entries in the hash table have not already been written out. The <> field of the <> structure controls which symbols are written out. The possible values are listed in <>. If the value is <>, then the <> field of the <> structure is a hash table of symbols to keep; each symbol should be looked up in this hash table, and only symbols which are present should be included in the output file. If the <> field of the <> structure permits local symbols to be written out, the <> field is used to further controls which local symbols are included in the output file. If the value is <>, then all local symbols which begin with a certain prefix are discarded; this prefix is described by the <> and <> fields of the <> structure. The a.out backend handles symbols by calling <> on each input BFD and then traversing the global hash table with the function <>. It builds a string table while writing out the symbols, which is written to the output file at the end of <>. */ static struct bfd_hash_entry *generic_link_hash_newfunc PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *)); static boolean generic_link_read_symbols PARAMS ((bfd *)); static boolean generic_link_add_symbols PARAMS ((bfd *, struct bfd_link_info *, boolean collect)); static boolean generic_link_add_object_symbols PARAMS ((bfd *, struct bfd_link_info *, boolean collect)); static boolean generic_link_check_archive_element_no_collect PARAMS ((bfd *, struct bfd_link_info *, boolean *pneeded)); static boolean generic_link_check_archive_element_collect PARAMS ((bfd *, struct bfd_link_info *, boolean *pneeded)); static boolean generic_link_check_archive_element PARAMS ((bfd *, struct bfd_link_info *, boolean *pneeded, boolean collect)); static boolean generic_link_add_symbol_list PARAMS ((bfd *, struct bfd_link_info *, bfd_size_type count, asymbol **, boolean collect)); static boolean generic_add_output_symbol PARAMS ((bfd *, size_t *psymalloc, asymbol *)); static boolean default_fill_link_order PARAMS ((bfd *, struct bfd_link_info *, asection *, struct bfd_link_order *)); static boolean default_indirect_link_order PARAMS ((bfd *, struct bfd_link_info *, asection *, struct bfd_link_order *)); /* The link hash table structure is defined in bfdlink.h. It provides a base hash table which the backend specific hash tables are built upon. */ /* Routine to create an entry in the link hash table. */ struct bfd_hash_entry * _bfd_link_hash_newfunc (entry, table, string) struct bfd_hash_entry *entry; struct bfd_hash_table *table; const char *string; { struct bfd_link_hash_entry *ret = (struct bfd_link_hash_entry *) entry; /* Allocate the structure if it has not already been allocated by a subclass. */ if (ret == (struct bfd_link_hash_entry *) NULL) ret = ((struct bfd_link_hash_entry *) bfd_hash_allocate (table, sizeof (struct bfd_link_hash_entry))); if (ret == (struct bfd_link_hash_entry *) NULL) { bfd_set_error (bfd_error_no_memory); return NULL; } /* Call the allocation method of the superclass. */ ret = ((struct bfd_link_hash_entry *) bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string)); if (ret) { /* Initialize the local fields. */ ret->type = bfd_link_hash_new; ret->next = NULL; } return (struct bfd_hash_entry *) ret; } /* Initialize a link hash table. The BFD argument is the one responsible for creating this table. */ boolean _bfd_link_hash_table_init (table, abfd, newfunc) struct bfd_link_hash_table *table; bfd *abfd; struct bfd_hash_entry *(*newfunc) PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *)); { table->creator = abfd->xvec; table->undefs = NULL; table->undefs_tail = NULL; return bfd_hash_table_init (&table->table, newfunc); } /* Look up a symbol in a link hash table. If follow is true, we follow bfd_link_hash_indirect and bfd_link_hash_warning links to the real symbol. */ struct bfd_link_hash_entry * bfd_link_hash_lookup (table, string, create, copy, follow) struct bfd_link_hash_table *table; const char *string; boolean create; boolean copy; boolean follow; { struct bfd_link_hash_entry *ret; ret = ((struct bfd_link_hash_entry *) bfd_hash_lookup (&table->table, string, create, copy)); if (follow && ret != (struct bfd_link_hash_entry *) NULL) { while (ret->type == bfd_link_hash_indirect || ret->type == bfd_link_hash_warning) ret = ret->u.i.link; } return ret; } /* Traverse a generic link hash table. The only reason this is not a macro is to do better type checking. This code presumes that an argument passed as a struct bfd_hash_entry * may be caught as a struct bfd_link_hash_entry * with no explicit cast required on the call. */ void bfd_link_hash_traverse (table, func, info) struct bfd_link_hash_table *table; boolean (*func) PARAMS ((struct bfd_link_hash_entry *, PTR)); PTR info; { bfd_hash_traverse (&table->table, ((boolean (*) PARAMS ((struct bfd_hash_entry *, PTR))) func), info); } /* Add a symbol to the linker hash table undefs list. */ INLINE void bfd_link_add_undef (table, h) struct bfd_link_hash_table *table; struct bfd_link_hash_entry *h; { BFD_ASSERT (h->next == NULL); if (table->undefs_tail != (struct bfd_link_hash_entry *) NULL) table->undefs_tail->next = h; if (table->undefs == (struct bfd_link_hash_entry *) NULL) table->undefs = h; table->undefs_tail = h; } /* Routine to create an entry in an generic link hash table. */ static struct bfd_hash_entry * generic_link_hash_newfunc (entry, table, string) struct bfd_hash_entry *entry; struct bfd_hash_table *table; const char *string; { struct generic_link_hash_entry *ret = (struct generic_link_hash_entry *) entry; /* Allocate the structure if it has not already been allocated by a subclass. */ if (ret == (struct generic_link_hash_entry *) NULL) ret = ((struct generic_link_hash_entry *) bfd_hash_allocate (table, sizeof (struct generic_link_hash_entry))); if (ret == (struct generic_link_hash_entry *) NULL) { bfd_set_error (bfd_error_no_memory); return NULL; } /* Call the allocation method of the superclass. */ ret = ((struct generic_link_hash_entry *) _bfd_link_hash_newfunc ((struct bfd_hash_entry *) ret, table, string)); if (ret) { /* Set local fields. */ ret->written = false; ret->sym = NULL; } return (struct bfd_hash_entry *) ret; } /* Create an generic link hash table. */ struct bfd_link_hash_table * _bfd_generic_link_hash_table_create (abfd) bfd *abfd; { struct generic_link_hash_table *ret; ret = ((struct generic_link_hash_table *) malloc (sizeof (struct generic_link_hash_table))); if (!ret) { bfd_set_error (bfd_error_no_memory); return (struct bfd_link_hash_table *) NULL; } if (! _bfd_link_hash_table_init (&ret->root, abfd, generic_link_hash_newfunc)) { free (ret); return (struct bfd_link_hash_table *) NULL; } return &ret->root; } /* Grab the symbols for an object file when doing a generic link. We store the symbols in the outsymbols field. We need to keep them around for the entire link to ensure that we only read them once. If we read them multiple times, we might wind up with relocs and the hash table pointing to different instances of the symbol structure. */ static boolean generic_link_read_symbols (abfd) bfd *abfd; { if (abfd->outsymbols == (asymbol **) NULL) { long symsize; long symcount; symsize = bfd_get_symtab_upper_bound (abfd); if (symsize < 0) return false; abfd->outsymbols = (asymbol **) bfd_alloc (abfd, symsize); if (abfd->outsymbols == NULL && symsize != 0) { bfd_set_error (bfd_error_no_memory); return false; } symcount = bfd_canonicalize_symtab (abfd, abfd->outsymbols); if (symcount < 0) return false; abfd->symcount = symcount; } return true; } /* Generic function to add symbols to from an object file to the global hash table. This version does not automatically collect constructors by name. */ boolean _bfd_generic_link_add_symbols (abfd, info) bfd *abfd; struct bfd_link_info *info; { return generic_link_add_symbols (abfd, info, false); } /* Generic function to add symbols from an object file to the global hash table. This version automatically collects constructors by name, as the collect2 program does. It should be used for any target which does not provide some other mechanism for setting up constructors and destructors; these are approximately those targets for which gcc uses collect2 and do not support stabs. */ boolean _bfd_generic_link_add_symbols_collect (abfd, info) bfd *abfd; struct bfd_link_info *info; { return generic_link_add_symbols (abfd, info, true); } /* Add symbols from an object file to the global hash table. */ static boolean generic_link_add_symbols (abfd, info, collect) bfd *abfd; struct bfd_link_info *info; boolean collect; { boolean ret; switch (bfd_get_format (abfd)) { case bfd_object: ret = generic_link_add_object_symbols (abfd, info, collect); break; case bfd_archive: ret = (_bfd_generic_link_add_archive_symbols (abfd, info, (collect ? generic_link_check_archive_element_collect : generic_link_check_archive_element_no_collect))); break; default: bfd_set_error (bfd_error_wrong_format); ret = false; } return ret; } /* Add symbols from an object file to the global hash table. */ static boolean generic_link_add_object_symbols (abfd, info, collect) bfd *abfd; struct bfd_link_info *info; boolean collect; { if (! generic_link_read_symbols (abfd)) return false; return generic_link_add_symbol_list (abfd, info, _bfd_generic_link_get_symcount (abfd), _bfd_generic_link_get_symbols (abfd), collect); } /* We build a hash table of all symbols defined in an archive. */ /* An archive symbol may be defined by multiple archive elements. This linked list is used to hold the elements. */ struct archive_list { struct archive_list *next; int indx; }; /* An entry in an archive hash table. */ struct archive_hash_entry { struct bfd_hash_entry root; /* Where the symbol is defined. */ struct archive_list *defs; }; /* An archive hash table itself. */ struct archive_hash_table { struct bfd_hash_table table; }; static struct bfd_hash_entry *archive_hash_newfunc PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *)); static boolean archive_hash_table_init PARAMS ((struct archive_hash_table *, struct bfd_hash_entry *(*) (struct bfd_hash_entry *, struct bfd_hash_table *, const char *))); /* Create a new entry for an archive hash table. */ static struct bfd_hash_entry * archive_hash_newfunc (entry, table, string) struct bfd_hash_entry *entry; struct bfd_hash_table *table; const char *string; { struct archive_hash_entry *ret = (struct archive_hash_entry *) entry; /* Allocate the structure if it has not already been allocated by a subclass. */ if (ret == (struct archive_hash_entry *) NULL) ret = ((struct archive_hash_entry *) bfd_hash_allocate (table, sizeof (struct archive_hash_entry))); if (ret == (struct archive_hash_entry *) NULL) { bfd_set_error (bfd_error_no_memory); return NULL; } /* Call the allocation method of the superclass. */ ret = ((struct archive_hash_entry *) bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string)); if (ret) { /* Initialize the local fields. */ ret->defs = (struct archive_list *) NULL; } return (struct bfd_hash_entry *) ret; } /* Initialize an archive hash table. */ static boolean archive_hash_table_init (table, newfunc) struct archive_hash_table *table; struct bfd_hash_entry *(*newfunc) PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *)); { return bfd_hash_table_init (&table->table, newfunc); } /* Look up an entry in an archive hash table. */ #define archive_hash_lookup(t, string, create, copy) \ ((struct archive_hash_entry *) \ bfd_hash_lookup (&(t)->table, (string), (create), (copy))) /* Free an archive hash table. */ #define archive_hash_table_free(t) bfd_hash_table_free (&(t)->table) /* Generic function to add symbols from an archive file to the global hash file. This function presumes that the archive symbol table has already been read in (this is normally done by the bfd_check_format entry point). It looks through the undefined and common symbols and searches the archive symbol table for them. If it finds an entry, it includes the associated object file in the link. The old linker looked through the archive symbol table for undefined symbols. We do it the other way around, looking through undefined symbols for symbols defined in the archive. The advantage of the newer scheme is that we only have to look through the list of undefined symbols once, whereas the old method had to re-search the symbol table each time a new object file was added. The CHECKFN argument is used to see if an object file should be included. CHECKFN should set *PNEEDED to true if the object file should be included, and must also call the bfd_link_info add_archive_element callback function and handle adding the symbols to the global hash table. CHECKFN should only return false if some sort of error occurs. For some formats, such as a.out, it is possible to look through an object file but not actually include it in the link. The archive_pass field in a BFD is used to avoid checking the symbols of an object files too many times. When an object is included in the link, archive_pass is set to -1. If an object is scanned but not included, archive_pass is set to the pass number. The pass number is incremented each time a new object file is included. The pass number is used because when a new object file is included it may create new undefined symbols which cause a previously examined object file to be included. */ boolean _bfd_generic_link_add_archive_symbols (abfd, info, checkfn) bfd *abfd; struct bfd_link_info *info; boolean (*checkfn) PARAMS ((bfd *, struct bfd_link_info *, boolean *pneeded)); { carsym *arsyms; carsym *arsym_end; register carsym *arsym; int pass; struct archive_hash_table arsym_hash; int indx; struct bfd_link_hash_entry **pundef; if (! bfd_has_map (abfd)) { bfd_set_error (bfd_error_no_symbols); return false; } arsyms = bfd_ardata (abfd)->symdefs; arsym_end = arsyms + bfd_ardata (abfd)->symdef_count; /* In order to quickly determine whether an symbol is defined in this archive, we build a hash table of the symbols. */ if (! archive_hash_table_init (&arsym_hash, archive_hash_newfunc)) return false; for (arsym = arsyms, indx = 0; arsym < arsym_end; arsym++, indx++) { struct archive_hash_entry *arh; struct archive_list *l, **pp; arh = archive_hash_lookup (&arsym_hash, arsym->name, true, false); if (arh == (struct archive_hash_entry *) NULL) goto error_return; l = (struct archive_list *) obstack_alloc (&(&(&arsym_hash)->table)->memory, sizeof (struct archive_list)); if (l == NULL) { bfd_set_error (bfd_error_no_memory); goto error_return; } l->indx = indx; for (pp = &arh->defs; *pp != (struct archive_list *) NULL; pp = &(*pp)->next) ; *pp = l; l->next = NULL; } pass = 1; /* New undefined symbols are added to the end of the list, so we only need to look through it once. */ pundef = &info->hash->undefs; while (*pundef != (struct bfd_link_hash_entry *) NULL) { struct bfd_link_hash_entry *h; struct archive_hash_entry *arh; struct archive_list *l; h = *pundef; /* When a symbol is defined, it is not necessarily removed from the list. */ if (h->type != bfd_link_hash_undefined && h->type != bfd_link_hash_common) { /* Remove this entry from the list, for general cleanliness and because we are going to look through the list again if we search any more libraries. We can't remove the entry if it is the tail, because that would lose any entries we add to the list later on. */ if (*pundef != info->hash->undefs_tail) *pundef = (*pundef)->next; else pundef = &(*pundef)->next; continue; } /* Look for this symbol in the archive symbol map. */ arh = archive_hash_lookup (&arsym_hash, h->root.string, false, false); if (arh == (struct archive_hash_entry *) NULL) { pundef = &(*pundef)->next; continue; } /* Look at all the objects which define this symbol. */ for (l = arh->defs; l != (struct archive_list *) NULL; l = l->next) { bfd *element; boolean needed; /* If the symbol has gotten defined along the way, quit. */ if (h->type != bfd_link_hash_undefined && h->type != bfd_link_hash_common) break; element = bfd_get_elt_at_index (abfd, l->indx); if (element == (bfd *) NULL) goto error_return; /* If we've already included this element, or if we've already checked it on this pass, continue. */ if (element->archive_pass == -1 || element->archive_pass == pass) continue; /* If we can't figure this element out, just ignore it. */ if (! bfd_check_format (element, bfd_object)) { element->archive_pass = -1; continue; } /* CHECKFN will see if this element should be included, and go ahead and include it if appropriate. */ if (! (*checkfn) (element, info, &needed)) goto error_return; if (! needed) element->archive_pass = pass; else { element->archive_pass = -1; /* Increment the pass count to show that we may need to recheck object files which were already checked. */ ++pass; } } pundef = &(*pundef)->next; } archive_hash_table_free (&arsym_hash); return true; error_return: archive_hash_table_free (&arsym_hash); return false; } /* See if we should include an archive element. This version is used when we do not want to automatically collect constructors based on the symbol name, presumably because we have some other mechanism for finding them. */ static boolean generic_link_check_archive_element_no_collect (abfd, info, pneeded) bfd *abfd; struct bfd_link_info *info; boolean *pneeded; { return generic_link_check_archive_element (abfd, info, pneeded, false); } /* See if we should include an archive element. This version is used when we want to automatically collect constructors based on the symbol name, as collect2 does. */ static boolean generic_link_check_archive_element_collect (abfd, info, pneeded) bfd *abfd; struct bfd_link_info *info; boolean *pneeded; { return generic_link_check_archive_element (abfd, info, pneeded, true); } /* See if we should include an archive element. Optionally collect constructors. */ static boolean generic_link_check_archive_element (abfd, info, pneeded, collect) bfd *abfd; struct bfd_link_info *info; boolean *pneeded; boolean collect; { asymbol **pp, **ppend; *pneeded = false; if (! generic_link_read_symbols (abfd)) return false; pp = _bfd_generic_link_get_symbols (abfd); ppend = pp + _bfd_generic_link_get_symcount (abfd); for (; pp < ppend; pp++) { asymbol *p; struct bfd_link_hash_entry *h; p = *pp; /* We are only interested in globally visible symbols. */ if (! bfd_is_com_section (p->section) && (p->flags & (BSF_GLOBAL | BSF_INDIRECT | BSF_WEAK)) == 0) continue; /* We are only interested if we know something about this symbol, and it is undefined or common. An undefined weak symbol (type bfd_link_hash_weak) is not considered to be a reference when pulling files out of an archive. See the SVR4 ABI, p. 4-27. */ h = bfd_link_hash_lookup (info->hash, bfd_asymbol_name (p), false, false, true); if (h == (struct bfd_link_hash_entry *) NULL || (h->type != bfd_link_hash_undefined && h->type != bfd_link_hash_common)) continue; /* P is a symbol we are looking for. */ if (! bfd_is_com_section (p->section)) { bfd_size_type symcount; asymbol **symbols; /* This object file defines this symbol, so pull it in. */ if (! (*info->callbacks->add_archive_element) (info, abfd, bfd_asymbol_name (p))) return false; symcount = _bfd_generic_link_get_symcount (abfd); symbols = _bfd_generic_link_get_symbols (abfd); if (! generic_link_add_symbol_list (abfd, info, symcount, symbols, collect)) return false; *pneeded = true; return true; } /* P is a common symbol. */ if (h->type == bfd_link_hash_undefined) { bfd *symbfd; symbfd = h->u.undef.abfd; if (symbfd == (bfd *) NULL) { /* This symbol was created as undefined from outside BFD. We assume that we should link in the object file. This is for the -u option in the linker. */ if (! (*info->callbacks->add_archive_element) (info, abfd, bfd_asymbol_name (p))) return false; *pneeded = true; return true; } /* Turn the symbol into a common symbol but do not link in the object file. This is how a.out works. Object formats that require different semantics must implement this function differently. This symbol is already on the undefs list. We add the section to a common section attached to symbfd to ensure that it is in a BFD which will be linked in. */ h->type = bfd_link_hash_common; h->u.c.size = bfd_asymbol_value (p); if (p->section == &bfd_com_section) h->u.c.section = bfd_make_section_old_way (symbfd, "COMMON"); else h->u.c.section = bfd_make_section_old_way (symbfd, p->section->name); h->u.c.section->flags = SEC_ALLOC; } else { /* Adjust the size of the common symbol if necessary. This is how a.out works. Object formats that require different semantics must implement this function differently. */ if (bfd_asymbol_value (p) > h->u.c.size) h->u.c.size = bfd_asymbol_value (p); } } /* This archive element is not needed. */ return true; } /* Add the symbols from an object file to the global hash table. ABFD is the object file. INFO is the linker information. SYMBOL_COUNT is the number of symbols. SYMBOLS is the list of symbols. COLLECT is true if constructors should be automatically collected by name as is done by collect2. */ static boolean generic_link_add_symbol_list (abfd, info, symbol_count, symbols, collect) bfd *abfd; struct bfd_link_info *info; bfd_size_type symbol_count; asymbol **symbols; boolean collect; { asymbol **pp, **ppend; pp = symbols; ppend = symbols + symbol_count; for (; pp < ppend; pp++) { asymbol *p; p = *pp; if ((p->flags & (BSF_INDIRECT | BSF_WARNING | BSF_GLOBAL | BSF_CONSTRUCTOR | BSF_WEAK)) != 0 || bfd_get_section (p) == &bfd_und_section || bfd_is_com_section (bfd_get_section (p)) || bfd_get_section (p) == &bfd_ind_section) { const char *name; const char *string; struct generic_link_hash_entry *h; name = bfd_asymbol_name (p); if ((p->flags & BSF_INDIRECT) != 0 || p->section == &bfd_ind_section) string = bfd_asymbol_name ((asymbol *) p->value); else if ((p->flags & BSF_WARNING) != 0) { /* The name of P is actually the warning string, and the value is actually a pointer to the symbol to warn about. */ string = name; name = bfd_asymbol_name ((asymbol *) p->value); } else string = NULL; h = NULL; if (! (_bfd_generic_link_add_one_symbol (info, abfd, name, p->flags, bfd_get_section (p), p->value, string, false, collect, (struct bfd_link_hash_entry **) &h))) return false; /* Save the BFD symbol so that we don't lose any backend specific information that may be attached to it. We only want this one if it gives more information than the existing one; we don't want to replace a defined symbol with an undefined one. This routine may be called with a hash table other than the generic hash table, so we only do this if we are certain that the hash table is a generic one. */ if (info->hash->creator == abfd->xvec) { if (h->sym == (asymbol *) NULL || (bfd_get_section (p) != &bfd_und_section && (! bfd_is_com_section (bfd_get_section (p)) || (bfd_get_section (h->sym) == &bfd_und_section)))) { h->sym = p; /* BSF_OLD_COMMON is a hack to support COFF reloc reading, and it should go away when the COFF linker is switched to the new version. */ if (bfd_is_com_section (bfd_get_section (p))) p->flags |= BSF_OLD_COMMON; } /* Store a back pointer from the symbol to the hash table entry for the benefit of relaxation code until it gets rewritten to not use asymbol structures. */ p->udata = (PTR) h; } } } return true; } /* We use a state table to deal with adding symbols from an object file. The first index into the state table describes the symbol from the object file. The second index into the state table is the type of the symbol in the hash table. */ /* The symbol from the object file is turned into one of these row values. */ enum link_row { UNDEF_ROW, /* Undefined. */ UNDEFW_ROW, /* Weak undefined. */ DEF_ROW, /* Defined. */ DEFW_ROW, /* Weak defined. */ COMMON_ROW, /* Common. */ INDR_ROW, /* Indirect. */ WARN_ROW, /* Warning. */ SET_ROW /* Member of set. */ }; /* The actions to take in the state table. */ enum link_action { FAIL, /* Abort. */ UND, /* Mark symbol undefined. */ WEAK, /* Mark symbol weak undefined. */ DEF, /* Mark symbol defined. */ COM, /* Mark symbol common. */ CREF, /* Possibly warn about common reference to defined symbol. */ CDEF, /* Define existing common symbol. */ NOACT, /* No action. */ BIG, /* Mark symbol common using largest size. */ MDEF, /* Multiple definition error. */ IND, /* Make indirect symbol. */ SET, /* Add value to set. */ MWARN, /* Make warning symbol. */ WARN, /* Issue warning. */ CYCLE, /* Repeat with symbol pointed to. */ WARNC /* Issue warning and then CYCLE. */ }; /* The state table itself. The first index is a link_row and the second index is a bfd_link_hash_type. */ static const enum link_action link_action[8][7] = { /* current\prev new undef weak def com indr warn */ /* UNDEF_ROW */ {UND, NOACT, NOACT, NOACT, NOACT, CYCLE, WARNC }, /* UNDEFW_ROW */ {WEAK, WEAK, NOACT, NOACT, NOACT, CYCLE, WARNC }, /* DEF_ROW */ {DEF, DEF, DEF, MDEF, CDEF, CYCLE, CYCLE }, /* DEFW_ROW */ {DEF, DEF, DEF, NOACT, NOACT, CYCLE, CYCLE }, /* COMMON_ROW */ {COM, COM, COM, CREF, BIG, CYCLE, WARNC }, /* INDR_ROW */ {IND, IND, IND, MDEF, MDEF, MDEF, WARNC }, /* WARN_ROW */ {MWARN, WARN, WARN, MWARN, MWARN, MWARN, NOACT }, /* SET_ROW */ {SET, SET, SET, SET, SET, CYCLE, WARNC } }; /* Add a symbol to the global hash table. ABFD is the BFD the symbol comes from. NAME is the name of the symbol. FLAGS is the BSF_* bits associated with the symbol. SECTION is the section in which the symbol is defined; this may be bfd_und_section or bfd_com_section. VALUE is the value of the symbol, relative to the section. STRING is used for either an indirect symbol, in which case it is the name of the symbol to indirect to, or a warning symbol, in which case it is the warning string. COPY is true if NAME or STRING must be copied into locally allocated memory if they need to be saved. COLLECT is true if we should automatically collect gcc constructor or destructor names as collect2 does. HASHP, if not NULL, is a place to store the created hash table entry; if *HASHP is not NULL, the caller has already looked up the hash table entry, and stored it in *HASHP. */ boolean _bfd_generic_link_add_one_symbol (info, abfd, name, flags, section, value, string, copy, collect, hashp) struct bfd_link_info *info; bfd *abfd; const char *name; flagword flags; asection *section; bfd_vma value; const char *string; boolean copy; boolean collect; struct bfd_link_hash_entry **hashp; { enum link_row row; struct bfd_link_hash_entry *h; boolean cycle; if (section == &bfd_ind_section || (flags & BSF_INDIRECT) != 0) row = INDR_ROW; else if ((flags & BSF_WARNING) != 0) row = WARN_ROW; else if ((flags & BSF_CONSTRUCTOR) != 0) row = SET_ROW; else if (section == &bfd_und_section) { if ((flags & BSF_WEAK) != 0) row = UNDEFW_ROW; else row = UNDEF_ROW; } else if ((flags & BSF_WEAK) != 0) row = DEFW_ROW; else if (bfd_is_com_section (section)) row = COMMON_ROW; else row = DEF_ROW; if (hashp != NULL && *hashp != NULL) { h = *hashp; BFD_ASSERT (strcmp (h->root.string, name) == 0); } else { h = bfd_link_hash_lookup (info->hash, name, true, copy, false); if (h == NULL) { if (hashp != NULL) *hashp = NULL; return false; } } if (info->notice_hash != (struct bfd_hash_table *) NULL && (bfd_hash_lookup (info->notice_hash, name, false, false) != (struct bfd_hash_entry *) NULL)) { if (! (*info->callbacks->notice) (info, name, abfd, section, value)) return false; } if (hashp != (struct bfd_link_hash_entry **) NULL) *hashp = h; do { enum link_action action; cycle = false; action = link_action[(int) row][(int) h->type]; switch (action) { case FAIL: abort (); case UND: h->type = bfd_link_hash_undefined; h->u.undef.abfd = abfd; bfd_link_add_undef (info->hash, h); break; case WEAK: h->type = bfd_link_hash_weak; h->u.undef.abfd = abfd; break; case CDEF: BFD_ASSERT (h->type == bfd_link_hash_common); if (! ((*info->callbacks->multiple_common) (info, name, h->u.c.section->owner, bfd_link_hash_common, h->u.c.size, abfd, bfd_link_hash_defined, (bfd_vma) 0))) return false; /* Fall through. */ case DEF: h->type = bfd_link_hash_defined; h->u.def.section = section; h->u.def.value = value; /* If we have been asked to, we act like collect2 and identify all functions that might be global constructors and destructors and pass them up in a callback. We only do this for certain object file types, since many object file types can handle this automatically. */ if (collect && name[0] == '_') { const char *s; /* A constructor or destructor name starts like this: _+GLOBAL_[_.$][ID][_.$] where the first [_.$] and the second are the same character (we accept any character there, in case a new object file format comes along with even worse naming restrictions). */ #define CONS_PREFIX "GLOBAL_" #define CONS_PREFIX_LEN (sizeof CONS_PREFIX - 1) s = name + 1; while (*s == '_') ++s; if (s[0] == 'G' && strncmp (s, CONS_PREFIX, CONS_PREFIX_LEN - 1) == 0) { char c; c = s[CONS_PREFIX_LEN + 1]; if ((c == 'I' || c == 'D') && s[CONS_PREFIX_LEN] == s[CONS_PREFIX_LEN + 2]) { if (! ((*info->callbacks->constructor) (info, c == 'I' ? true : false, name, abfd, section, value))) return false; } } } break; case COM: if (h->type == bfd_link_hash_new) bfd_link_add_undef (info->hash, h); h->type = bfd_link_hash_common; h->u.c.size = value; if (section == &bfd_com_section) { h->u.c.section = bfd_make_section_old_way (abfd, "COMMON"); h->u.c.section->flags = SEC_ALLOC; } else if (section->owner != abfd) { h->u.c.section = bfd_make_section_old_way (abfd, section->name); h->u.c.section->flags = SEC_ALLOC; } else h->u.c.section = section; break; case NOACT: break; case BIG: BFD_ASSERT (h->type == bfd_link_hash_common); if (! ((*info->callbacks->multiple_common) (info, name, h->u.c.section->owner, bfd_link_hash_common, h->u.c.size, abfd, bfd_link_hash_common, value))) return false; if (value > h->u.c.size) h->u.c.size = value; break; case CREF: BFD_ASSERT (h->type == bfd_link_hash_defined); if (! ((*info->callbacks->multiple_common) (info, name, h->u.def.section->owner, bfd_link_hash_defined, (bfd_vma) 0, abfd, bfd_link_hash_common, value))) return false; break; case MDEF: { asection *msec; bfd_vma mval; switch (h->type) { case bfd_link_hash_defined: msec = h->u.def.section; mval = h->u.def.value; break; case bfd_link_hash_common: msec = &bfd_com_section; mval = h->u.c.size; break; case bfd_link_hash_indirect: msec = &bfd_ind_section; mval = 0; break; default: abort (); } if (! ((*info->callbacks->multiple_definition) (info, name, msec->owner, msec, mval, abfd, section, value))) return false; } break; case IND: { struct bfd_link_hash_entry *inh; /* STRING is the name of the symbol we want to indirect to. */ inh = bfd_link_hash_lookup (info->hash, string, true, copy, false); if (inh == (struct bfd_link_hash_entry *) NULL) return false; if (inh->type == bfd_link_hash_new) { inh->type = bfd_link_hash_undefined; inh->u.undef.abfd = abfd; bfd_link_add_undef (info->hash, inh); } h->type = bfd_link_hash_indirect; h->u.i.link = inh; } break; case SET: if (! (*info->callbacks->add_to_set) (info, h, BFD_RELOC_CTOR, abfd, section, value)) return false; break; case WARN: case WARNC: if (h->u.i.warning != NULL) { if (! (*info->callbacks->warning) (info, h->u.i.warning)) return false; /* Only issue a warning once. */ h->u.i.warning = NULL; } if (action == WARN) break; /* Fall through. */ case CYCLE: h = h->u.i.link; cycle = true; break; case MWARN: { struct bfd_link_hash_entry *sub; /* STRING is the warning to give. */ sub = ((struct bfd_link_hash_entry *) bfd_hash_allocate (&info->hash->table, sizeof (struct bfd_link_hash_entry))); if (!sub) { bfd_set_error (bfd_error_no_memory); return false; } *sub = *h; h->type = bfd_link_hash_warning; h->u.i.link = sub; if (! copy) h->u.i.warning = string; else { char *w; w = bfd_hash_allocate (&info->hash->table, strlen (string) + 1); strcpy (w, string); h->u.i.warning = w; } } break; } } while (cycle); return true; } /* Generic final link routine. */ boolean _bfd_generic_final_link (abfd, info) bfd *abfd; struct bfd_link_info *info; { bfd *sub; asection *o; struct bfd_link_order *p; size_t outsymalloc; struct generic_write_global_symbol_info wginfo; abfd->outsymbols = (asymbol **) NULL; abfd->symcount = 0; outsymalloc = 0; /* Build the output symbol table. */ for (sub = info->input_bfds; sub != (bfd *) NULL; sub = sub->link_next) if (! _bfd_generic_link_output_symbols (abfd, sub, info, &outsymalloc)) return false; /* Accumulate the global symbols. */ wginfo.info = info; wginfo.output_bfd = abfd; wginfo.psymalloc = &outsymalloc; _bfd_generic_link_hash_traverse (_bfd_generic_hash_table (info), _bfd_generic_link_write_global_symbol, (PTR) &wginfo); if (info->relocateable) { /* Allocate space for the output relocs for each section. */ for (o = abfd->sections; o != (asection *) NULL; o = o->next) { o->reloc_count = 0; for (p = o->link_order_head; p != (struct bfd_link_order *) NULL; p = p->next) { if (p->type == bfd_section_reloc_link_order || p->type == bfd_symbol_reloc_link_order) ++o->reloc_count; else if (p->type == bfd_indirect_link_order) { asection *input_section; bfd *input_bfd; long relsize; arelent **relocs; asymbol **symbols; long reloc_count; input_section = p->u.indirect.section; input_bfd = input_section->owner; relsize = bfd_get_reloc_upper_bound (input_bfd, input_section); if (relsize < 0) return false; relocs = (arelent **) malloc ((size_t) relsize); if (!relocs && relsize != 0) { bfd_set_error (bfd_error_no_memory); return false; } symbols = _bfd_generic_link_get_symbols (input_bfd); reloc_count = bfd_canonicalize_reloc (input_bfd, input_section, relocs, symbols); if (reloc_count < 0) return false; BFD_ASSERT (reloc_count == input_section->reloc_count); o->reloc_count += reloc_count; free (relocs); } } if (o->reloc_count > 0) { o->orelocation = ((arelent **) bfd_alloc (abfd, (o->reloc_count * sizeof (arelent *)))); if (!o->orelocation) { bfd_set_error (bfd_error_no_memory); return false; } o->flags |= SEC_RELOC; /* Reset the count so that it can be used as an index when putting in the output relocs. */ o->reloc_count = 0; } } } /* Handle all the link order information for the sections. */ for (o = abfd->sections; o != (asection *) NULL; o = o->next) { for (p = o->link_order_head; p != (struct bfd_link_order *) NULL; p = p->next) { switch (p->type) { case bfd_section_reloc_link_order: case bfd_symbol_reloc_link_order: if (! _bfd_generic_reloc_link_order (abfd, info, o, p)) return false; break; default: if (! _bfd_default_link_order (abfd, info, o, p)) return false; break; } } } return true; } /* Add an output symbol to the output BFD. */ static boolean generic_add_output_symbol (output_bfd, psymalloc, sym) bfd *output_bfd; size_t *psymalloc; asymbol *sym; { if (output_bfd->symcount >= *psymalloc) { asymbol **newsyms; if (*psymalloc == 0) *psymalloc = 124; else *psymalloc *= 2; if (output_bfd->outsymbols == (asymbol **) NULL) newsyms = (asymbol **) malloc (*psymalloc * sizeof (asymbol *)); else newsyms = (asymbol **) realloc (output_bfd->outsymbols, *psymalloc * sizeof (asymbol *)); if (newsyms == (asymbol **) NULL) { bfd_set_error (bfd_error_no_memory); return false; } output_bfd->outsymbols = newsyms; } output_bfd->outsymbols[output_bfd->symcount] = sym; ++output_bfd->symcount; return true; } /* Handle the symbols for an input BFD. */ boolean _bfd_generic_link_output_symbols (output_bfd, input_bfd, info, psymalloc) bfd *output_bfd; bfd *input_bfd; struct bfd_link_info *info; size_t *psymalloc; { asymbol **sym_ptr; asymbol **sym_end; if (! generic_link_read_symbols (input_bfd)) return false; /* Create a filename symbol if we are supposed to. */ if (info->create_object_symbols_section != (asection *) NULL) { asection *sec; for (sec = input_bfd->sections; sec != (asection *) NULL; sec = sec->next) { if (sec->output_section == info->create_object_symbols_section) { asymbol *newsym; newsym = bfd_make_empty_symbol (input_bfd); if (!newsym) return false; newsym->name = input_bfd->filename; newsym->value = 0; newsym->flags = BSF_LOCAL | BSF_FILE; newsym->section = sec; if (! generic_add_output_symbol (output_bfd, psymalloc, newsym)) return false; break; } } } /* Adjust the values of the globally visible symbols, and write out local symbols. */ sym_ptr = _bfd_generic_link_get_symbols (input_bfd); sym_end = sym_ptr + _bfd_generic_link_get_symcount (input_bfd); for (; sym_ptr < sym_end; sym_ptr++) { asymbol *sym; struct generic_link_hash_entry *h; boolean output; h = (struct generic_link_hash_entry *) NULL; sym = *sym_ptr; if ((sym->flags & (BSF_INDIRECT | BSF_WARNING | BSF_GLOBAL | BSF_CONSTRUCTOR | BSF_WEAK)) != 0 || bfd_get_section (sym) == &bfd_und_section || bfd_is_com_section (bfd_get_section (sym)) || bfd_get_section (sym) == &bfd_ind_section) { h = _bfd_generic_link_hash_lookup (_bfd_generic_hash_table (info), bfd_asymbol_name (sym), false, false, true); if (h != (struct generic_link_hash_entry *) NULL) { /* Force all references to this symbol to point to the same area in memory. It is possible that this routine will be called with a hash table other than a generic hash table, so we double check that. */ if (info->hash->creator == input_bfd->xvec) { if (h->sym != (asymbol *) NULL) *sym_ptr = sym = h->sym; } switch (h->root.type) { default: case bfd_link_hash_new: abort (); case bfd_link_hash_undefined: case bfd_link_hash_weak: break; case bfd_link_hash_defined: sym->value = h->root.u.def.value; sym->section = h->root.u.def.section; sym->flags |= BSF_GLOBAL; break; case bfd_link_hash_common: sym->value = h->root.u.c.size; sym->flags |= BSF_GLOBAL; if (! bfd_is_com_section (sym->section)) { BFD_ASSERT (sym->section == &bfd_und_section); sym->section = &bfd_com_section; } /* We do not set the section of the symbol to h->root.u.c.section. That value was saved so that we would know where to allocate the symbol if it was defined. In this case the type is still bfd_link_hash_common, so we did not define it, so we do not want to use that section. */ break; } } } /* This switch is straight from the old code in write_file_locals in ldsym.c. */ if (info->strip == strip_some && (bfd_hash_lookup (info->keep_hash, bfd_asymbol_name (sym), false, false) == (struct bfd_hash_entry *) NULL)) output = false; else if ((sym->flags & (BSF_GLOBAL | BSF_WEAK)) != 0) { /* If this symbol is marked as occurring now, rather than at the end, output it now. This is used for COFF C_EXT FCN symbols. FIXME: There must be a better way. */ if (bfd_asymbol_bfd (sym) == input_bfd && (sym->flags & BSF_NOT_AT_END) != 0) output = true; else output = false; } else if (sym->section == &bfd_ind_section) output = false; else if ((sym->flags & BSF_DEBUGGING) != 0) { if (info->strip == strip_none) output = true; else output = false; } else if (sym->section == &bfd_und_section || bfd_is_com_section (sym->section)) output = false; else if ((sym->flags & BSF_LOCAL) != 0) { if ((sym->flags & BSF_WARNING) != 0) output = false; else { switch (info->discard) { default: case discard_all: output = false; break; case discard_l: if (bfd_asymbol_name (sym)[0] == info->lprefix[0] && (info->lprefix_len == 1 || strncmp (bfd_asymbol_name (sym), info->lprefix, info->lprefix_len) == 0)) output = false; else output = true; break; case discard_none: output = true; break; } } } else if ((sym->flags & BSF_CONSTRUCTOR)) { if (info->strip != strip_all) output = true; else output = false; } else abort (); if (output) { if (! generic_add_output_symbol (output_bfd, psymalloc, sym)) return false; if (h != (struct generic_link_hash_entry *) NULL) h->written = true; } } return true; } /* Write out a global symbol, if it hasn't already been written out. This is called for each symbol in the hash table. */ boolean _bfd_generic_link_write_global_symbol (h, data) struct generic_link_hash_entry *h; PTR data; { struct generic_write_global_symbol_info *wginfo = (struct generic_write_global_symbol_info *) data; asymbol *sym; if (h->written) return true; h->written = true; if (wginfo->info->strip == strip_all || (wginfo->info->strip == strip_some && bfd_hash_lookup (wginfo->info->keep_hash, h->root.root.string, false, false) == NULL)) return true; if (h->sym != (asymbol *) NULL) { sym = h->sym; BFD_ASSERT (strcmp (bfd_asymbol_name (sym), h->root.root.string) == 0); } else { sym = bfd_make_empty_symbol (wginfo->output_bfd); if (!sym) return false; sym->name = h->root.root.string; sym->flags = 0; } switch (h->root.type) { default: case bfd_link_hash_new: abort (); case bfd_link_hash_undefined: sym->section = &bfd_und_section; sym->value = 0; break; case bfd_link_hash_weak: sym->section = &bfd_und_section; sym->value = 0; sym->flags |= BSF_WEAK; break; case bfd_link_hash_defined: sym->section = h->root.u.def.section; sym->value = h->root.u.def.value; break; case bfd_link_hash_common: sym->value = h->root.u.c.size; if (! bfd_is_com_section (sym->section)) { BFD_ASSERT (sym->section == &bfd_und_section); sym->section = &bfd_com_section; } /* Do not set the section; see _bfd_generic_link_output_symbols. */ break; case bfd_link_hash_indirect: case bfd_link_hash_warning: /* FIXME: What should we do here? */ break; } sym->flags |= BSF_GLOBAL; if (! generic_add_output_symbol (wginfo->output_bfd, wginfo->psymalloc, sym)) { /* FIXME: No way to return failure. */ abort (); } return true; } /* Create a relocation. */ boolean _bfd_generic_reloc_link_order (abfd, info, sec, link_order) bfd *abfd; struct bfd_link_info *info; asection *sec; struct bfd_link_order *link_order; { arelent *r; if (! info->relocateable) abort (); if (sec->orelocation == (arelent **) NULL) abort (); r = (arelent *) bfd_alloc (abfd, sizeof (arelent)); if (r == (arelent *) NULL) { bfd_set_error (bfd_error_no_memory); return false; } r->address = link_order->offset; r->howto = bfd_reloc_type_lookup (abfd, link_order->u.reloc.p->reloc); if (r->howto == (const reloc_howto_type *) NULL) { bfd_set_error (bfd_error_bad_value); return false; } /* Get the symbol to use for the relocation. */ if (link_order->type == bfd_section_reloc_link_order) r->sym_ptr_ptr = link_order->u.reloc.p->u.section->symbol_ptr_ptr; else { struct generic_link_hash_entry *h; h = _bfd_generic_link_hash_lookup (_bfd_generic_hash_table (info), link_order->u.reloc.p->u.name, false, false, true); if (h == (struct generic_link_hash_entry *) NULL || ! h->written) { if (! ((*info->callbacks->unattached_reloc) (info, link_order->u.reloc.p->u.name, (bfd *) NULL, (asection *) NULL, (bfd_vma) 0))) return false; bfd_set_error (bfd_error_bad_value); return false; } r->sym_ptr_ptr = &h->sym; } /* If this is an inplace reloc, write the addend to the object file. Otherwise, store it in the reloc addend. */ if (! r->howto->partial_inplace) r->addend = link_order->u.reloc.p->addend; else { bfd_size_type size; bfd_reloc_status_type rstat; bfd_byte *buf; boolean ok; size = bfd_get_reloc_size (r->howto); buf = (bfd_byte *) bfd_zmalloc (size); if (buf == (bfd_byte *) NULL) { bfd_set_error (bfd_error_no_memory); return false; } rstat = _bfd_relocate_contents (r->howto, abfd, link_order->u.reloc.p->addend, buf); switch (rstat) { case bfd_reloc_ok: break; default: case bfd_reloc_outofrange: abort (); case bfd_reloc_overflow: if (! ((*info->callbacks->reloc_overflow) (info, (link_order->type == bfd_section_reloc_link_order ? bfd_section_name (abfd, link_order->u.reloc.p->u.section) : link_order->u.reloc.p->u.name), r->howto->name, link_order->u.reloc.p->addend, (bfd *) NULL, (asection *) NULL, (bfd_vma) 0))) { free (buf); return false; } break; } ok = bfd_set_section_contents (abfd, sec, (PTR) buf, (file_ptr) link_order->offset, size); free (buf); if (! ok) return false; r->addend = 0; } sec->orelocation[sec->reloc_count] = r; ++sec->reloc_count; return true; } /* Allocate a new link_order for a section. */ struct bfd_link_order * bfd_new_link_order (abfd, section) bfd *abfd; asection *section; { struct bfd_link_order *new; new = ((struct bfd_link_order *) bfd_alloc_by_size_t (abfd, sizeof (struct bfd_link_order))); if (!new) { bfd_set_error (bfd_error_no_memory); return NULL; } new->type = bfd_undefined_link_order; new->offset = 0; new->size = 0; new->next = (struct bfd_link_order *) NULL; if (section->link_order_tail != (struct bfd_link_order *) NULL) section->link_order_tail->next = new; else section->link_order_head = new; section->link_order_tail = new; return new; } /* Default link order processing routine. Note that we can not handle the reloc_link_order types here, since they depend upon the details of how the particular backends generates relocs. */ boolean _bfd_default_link_order (abfd, info, sec, link_order) bfd *abfd; struct bfd_link_info *info; asection *sec; struct bfd_link_order *link_order; { switch (link_order->type) { case bfd_undefined_link_order: case bfd_section_reloc_link_order: case bfd_symbol_reloc_link_order: default: abort (); case bfd_indirect_link_order: return default_indirect_link_order (abfd, info, sec, link_order); case bfd_fill_link_order: return default_fill_link_order (abfd, info, sec, link_order); case bfd_data_link_order: return bfd_set_section_contents (abfd, sec, (PTR) link_order->u.data.contents, (file_ptr) link_order->offset, link_order->size); } } /* Default routine to handle a bfd_fill_link_order. */ /*ARGSUSED*/ static boolean default_fill_link_order (abfd, info, sec, link_order) bfd *abfd; struct bfd_link_info *info; asection *sec; struct bfd_link_order *link_order; { size_t size; char *space; size_t i; int fill; boolean result; BFD_ASSERT ((sec->flags & SEC_HAS_CONTENTS) != 0); size = (size_t) link_order->size; space = (char *) malloc (size); if (space == NULL && size != 0) { bfd_set_error (bfd_error_no_memory); return false; } fill = link_order->u.fill.value; for (i = 0; i < size; i += 2) space[i] = fill >> 8; for (i = 1; i < size; i += 2) space[i] = fill; result = bfd_set_section_contents (abfd, sec, space, (file_ptr) link_order->offset, link_order->size); free (space); return result; } /* Default routine to handle a bfd_indirect_link_order. */ static boolean default_indirect_link_order (output_bfd, info, output_section, link_order) bfd *output_bfd; struct bfd_link_info *info; asection *output_section; struct bfd_link_order *link_order; { asection *input_section; bfd *input_bfd; bfd_byte *contents = NULL; bfd_byte *new_contents; BFD_ASSERT ((output_section->flags & SEC_HAS_CONTENTS) != 0); if (link_order->size == 0) return true; input_section = link_order->u.indirect.section; input_bfd = input_section->owner; BFD_ASSERT (input_section->output_section == output_section); BFD_ASSERT (input_section->output_offset == link_order->offset); BFD_ASSERT (input_section->_cooked_size == link_order->size); if (info->relocateable && input_section->reloc_count > 0 && output_section->orelocation == (arelent **) NULL) { /* Space has not been allocated for the output relocations. This can happen when we are called by a specific backend because somebody is attempting to link together different types of object files. Handling this case correctly is difficult, and sometimes impossible. */ abort (); } /* Get the canonical symbols. The generic linker will always have retrieved them by this point, but we may be being called by a specific linker when linking different types of object files together. */ if (! generic_link_read_symbols (input_bfd)) return false; /* Get and relocate the section contents. */ contents = (bfd_byte *) malloc (bfd_section_size (input_bfd, input_section)); if (contents == NULL && bfd_section_size (input_bfd, input_section) != 0) { bfd_set_error (bfd_error_no_memory); goto error_return; } new_contents = (bfd_get_relocated_section_contents (output_bfd, info, link_order, contents, info->relocateable, _bfd_generic_link_get_symbols (input_bfd))); if (!new_contents) goto error_return; /* Output the section contents. */ if (! bfd_set_section_contents (output_bfd, output_section, (PTR) new_contents, link_order->offset, link_order->size)) goto error_return; if (contents != NULL) free (contents); return true; error_return: if (contents != NULL) free (contents); return false; } /* A little routine to count the number of relocs in a link_order list. */ unsigned int _bfd_count_link_order_relocs (link_order) struct bfd_link_order *link_order; { register unsigned int c; register struct bfd_link_order *l; c = 0; for (l = link_order; l != (struct bfd_link_order *) NULL; l = l->next) { if (l->type == bfd_section_reloc_link_order || l->type == bfd_symbol_reloc_link_order) ++c; } return c; }