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- /* ldwrite.c -- write out the linked file
- Copyright (C) 1991-2022 Free Software Foundation, Inc.
- Written by Steve Chamberlain sac@cygnus.com
- This file is part of the GNU Binutils.
- 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 3 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., 51 Franklin Street - Fifth Floor, Boston,
- MA 02110-1301, USA. */
- #include "sysdep.h"
- #include "bfd.h"
- #include "bfdlink.h"
- #include "libiberty.h"
- #include "ctf-api.h"
- #include "safe-ctype.h"
- #include "ld.h"
- #include "ldexp.h"
- #include "ldlang.h"
- #include "ldwrite.h"
- #include "ldmisc.h"
- #include <ldgram.h>
- #include "ldmain.h"
- /* Build link_order structures for the BFD linker. */
- static void
- build_link_order (lang_statement_union_type *statement)
- {
- switch (statement->header.type)
- {
- case lang_data_statement_enum:
- {
- asection *output_section;
- struct bfd_link_order *link_order;
- bfd_vma value;
- output_section = statement->data_statement.output_section;
- ASSERT (output_section->owner == link_info.output_bfd);
- if (!((output_section->flags & SEC_HAS_CONTENTS) != 0
- || ((output_section->flags & SEC_LOAD) != 0
- && (output_section->flags & SEC_THREAD_LOCAL))))
- break;
- link_order = bfd_new_link_order (link_info.output_bfd, output_section);
- if (link_order == NULL)
- einfo (_("%F%P: bfd_new_link_order failed\n"));
- link_order->type = bfd_data_link_order;
- link_order->offset = statement->data_statement.output_offset;
- link_order->u.data.contents = (bfd_byte *) xmalloc (QUAD_SIZE);
- value = statement->data_statement.value;
- /* By convention, the bfd_put routines for an unknown
- endianness are big endian, so we must swap here if the
- input is little endian. */
- if (!bfd_big_endian (link_info.output_bfd)
- && !bfd_little_endian (link_info.output_bfd)
- && !link_info.big_endian)
- {
- bfd_byte buffer[8];
- switch (statement->data_statement.type)
- {
- case QUAD:
- case SQUAD:
- if (sizeof (bfd_vma) >= QUAD_SIZE)
- {
- bfd_putl64 (value, buffer);
- value = bfd_getb64 (buffer);
- break;
- }
- /* Fall through. */
- case LONG:
- bfd_putl32 (value, buffer);
- value = bfd_getb32 (buffer);
- break;
- case SHORT:
- bfd_putl16 (value, buffer);
- value = bfd_getb16 (buffer);
- break;
- case BYTE:
- break;
- default:
- abort ();
- }
- }
- ASSERT (output_section->owner == link_info.output_bfd);
- switch (statement->data_statement.type)
- {
- case QUAD:
- case SQUAD:
- if (sizeof (bfd_vma) >= QUAD_SIZE)
- bfd_put_64 (link_info.output_bfd, value,
- link_order->u.data.contents);
- else
- {
- bfd_vma high;
- if (statement->data_statement.type == QUAD)
- high = 0;
- else if ((value & 0x80000000) == 0)
- high = 0;
- else
- high = (bfd_vma) -1;
- bfd_put_32 (link_info.output_bfd, high,
- (link_order->u.data.contents
- + (link_info.big_endian ? 0 : 4)));
- bfd_put_32 (link_info.output_bfd, value,
- (link_order->u.data.contents
- + (link_info.big_endian ? 4 : 0)));
- }
- link_order->size = QUAD_SIZE;
- break;
- case LONG:
- bfd_put_32 (link_info.output_bfd, value,
- link_order->u.data.contents);
- link_order->size = LONG_SIZE;
- break;
- case SHORT:
- bfd_put_16 (link_info.output_bfd, value,
- link_order->u.data.contents);
- link_order->size = SHORT_SIZE;
- break;
- case BYTE:
- bfd_put_8 (link_info.output_bfd, value,
- link_order->u.data.contents);
- link_order->size = BYTE_SIZE;
- break;
- default:
- abort ();
- }
- link_order->u.data.size = link_order->size;
- }
- break;
- case lang_reloc_statement_enum:
- {
- lang_reloc_statement_type *rs;
- asection *output_section;
- struct bfd_link_order *link_order;
- rs = &statement->reloc_statement;
- output_section = rs->output_section;
- ASSERT (output_section->owner == link_info.output_bfd);
- if (!((output_section->flags & SEC_HAS_CONTENTS) != 0
- || ((output_section->flags & SEC_LOAD) != 0
- && (output_section->flags & SEC_THREAD_LOCAL))))
- break;
- link_order = bfd_new_link_order (link_info.output_bfd, output_section);
- if (link_order == NULL)
- einfo (_("%F%P: bfd_new_link_order failed\n"));
- link_order->offset = rs->output_offset;
- link_order->size = bfd_get_reloc_size (rs->howto);
- link_order->u.reloc.p = (struct bfd_link_order_reloc *)
- xmalloc (sizeof (struct bfd_link_order_reloc));
- link_order->u.reloc.p->reloc = rs->reloc;
- link_order->u.reloc.p->addend = rs->addend_value;
- if (rs->name == NULL)
- {
- link_order->type = bfd_section_reloc_link_order;
- if (rs->section->owner == link_info.output_bfd)
- link_order->u.reloc.p->u.section = rs->section;
- else
- {
- link_order->u.reloc.p->u.section = rs->section->output_section;
- link_order->u.reloc.p->addend += rs->section->output_offset;
- }
- }
- else
- {
- link_order->type = bfd_symbol_reloc_link_order;
- link_order->u.reloc.p->u.name = rs->name;
- }
- }
- break;
- case lang_input_section_enum:
- {
- /* Create a new link_order in the output section with this
- attached */
- asection *i = statement->input_section.section;
- if (i->sec_info_type != SEC_INFO_TYPE_JUST_SYMS
- && (i->flags & SEC_EXCLUDE) == 0)
- {
- asection *output_section = i->output_section;
- struct bfd_link_order *link_order;
- ASSERT (output_section->owner == link_info.output_bfd);
- if (!((output_section->flags & SEC_HAS_CONTENTS) != 0
- || ((output_section->flags & SEC_LOAD) != 0
- && (output_section->flags & SEC_THREAD_LOCAL))))
- break;
- link_order = bfd_new_link_order (link_info.output_bfd,
- output_section);
- if (link_order == NULL)
- einfo (_("%F%P: bfd_new_link_order failed\n"));
- if ((i->flags & SEC_NEVER_LOAD) != 0
- && (i->flags & SEC_DEBUGGING) == 0)
- {
- /* We've got a never load section inside one which is
- going to be output, we'll change it into a fill. */
- link_order->type = bfd_data_link_order;
- link_order->u.data.contents = (unsigned char *) "";
- link_order->u.data.size = 1;
- }
- else
- {
- link_order->type = bfd_indirect_link_order;
- link_order->u.indirect.section = i;
- ASSERT (i->output_section == output_section);
- }
- link_order->size = i->size;
- link_order->offset = i->output_offset;
- }
- }
- break;
- case lang_padding_statement_enum:
- /* Make a new link_order with the right filler */
- {
- asection *output_section;
- struct bfd_link_order *link_order;
- output_section = statement->padding_statement.output_section;
- ASSERT (statement->padding_statement.output_section->owner
- == link_info.output_bfd);
- if (!((output_section->flags & SEC_HAS_CONTENTS) != 0
- || ((output_section->flags & SEC_LOAD) != 0
- && (output_section->flags & SEC_THREAD_LOCAL))))
- break;
- link_order = bfd_new_link_order (link_info.output_bfd,
- output_section);
- if (link_order == NULL)
- einfo (_("%F%P: bfd_new_link_order failed\n"));
- link_order->type = bfd_data_link_order;
- link_order->size = statement->padding_statement.size;
- link_order->offset = statement->padding_statement.output_offset;
- link_order->u.data.contents = statement->padding_statement.fill->data;
- link_order->u.data.size = statement->padding_statement.fill->size;
- }
- break;
- default:
- /* All the other ones fall through */
- break;
- }
- }
- /* Return true if NAME is the name of an unsplittable section. These
- are the stabs strings, dwarf strings. */
- static bool
- unsplittable_name (const char *name)
- {
- if (startswith (name, ".stab"))
- {
- /* There are several stab like string sections. We pattern match on
- ".stab...str" */
- unsigned len = strlen (name);
- if (strcmp (&name[len-3], "str") == 0)
- return true;
- }
- else if (strcmp (name, "$GDB_STRINGS$") == 0)
- return true;
- return false;
- }
- /* Wander around the input sections, make sure that
- we'll never try and create an output section with more relocs
- than will fit.. Do this by always assuming the worst case, and
- creating new output sections with all the right bits. */
- #define TESTIT 1
- static asection *
- clone_section (bfd *abfd, asection *s, const char *name, int *count)
- {
- char *tname;
- char *sname;
- unsigned int len;
- asection *n;
- struct bfd_link_hash_entry *h;
- /* Invent a section name from the section name and a dotted numeric
- suffix. */
- len = strlen (name);
- tname = (char *) xmalloc (len + 1);
- memcpy (tname, name, len + 1);
- /* Remove a dotted number suffix, from a previous split link. */
- while (len && ISDIGIT (tname[len-1]))
- len--;
- if (len > 1 && tname[len-1] == '.')
- /* It was a dotted number. */
- tname[len-1] = 0;
- /* We want to use the whole of the original section name for the
- split name, but coff can be restricted to 8 character names. */
- if (bfd_family_coff (abfd) && strlen (tname) > 5)
- {
- /* Some section names cannot be truncated, as the name is
- used to locate some other section. */
- if (startswith (name, ".stab")
- || strcmp (name, "$GDB_SYMBOLS$") == 0)
- {
- einfo (_ ("%F%P: cannot create split section name for %s\n"), name);
- /* Silence gcc warnings. einfo exits, so we never reach here. */
- return NULL;
- }
- tname[5] = 0;
- }
- if ((sname = bfd_get_unique_section_name (abfd, tname, count)) == NULL
- || (n = bfd_make_section_anyway (abfd, sname)) == NULL
- || (h = bfd_link_hash_lookup (link_info.hash,
- sname, true, true, false)) == NULL)
- {
- einfo (_("%F%P: clone section failed: %E\n"));
- /* Silence gcc warnings. einfo exits, so we never reach here. */
- return NULL;
- }
- free (tname);
- /* Set up section symbol. */
- h->type = bfd_link_hash_defined;
- h->u.def.value = 0;
- h->u.def.section = n;
- n->flags = s->flags;
- n->vma = s->vma;
- n->user_set_vma = s->user_set_vma;
- n->lma = s->lma;
- n->size = 0;
- n->output_offset = s->output_offset;
- n->output_section = n;
- n->orelocation = 0;
- n->reloc_count = 0;
- n->alignment_power = s->alignment_power;
- bfd_copy_private_section_data (abfd, s, abfd, n);
- return n;
- }
- #if TESTING
- static void
- ds (asection *s)
- {
- struct bfd_link_order *l = s->map_head.link_order;
- printf ("vma %x size %x\n", s->vma, s->size);
- while (l)
- {
- if (l->type == bfd_indirect_link_order)
- printf ("%8x %s\n", l->offset, l->u.indirect.section->owner->filename);
- else
- printf (_("%8x something else\n"), l->offset);
- l = l->next;
- }
- printf ("\n");
- }
- dump (char *s, asection *a1, asection *a2)
- {
- printf ("%s\n", s);
- ds (a1);
- ds (a2);
- }
- static void
- sanity_check (bfd *abfd)
- {
- asection *s;
- for (s = abfd->sections; s; s = s->next)
- {
- struct bfd_link_order *p;
- bfd_vma prev = 0;
- for (p = s->map_head.link_order; p; p = p->next)
- {
- if (p->offset > 100000)
- abort ();
- if (p->offset < prev)
- abort ();
- prev = p->offset;
- }
- }
- }
- #else
- #define sanity_check(a)
- #define dump(a, b, c)
- #endif
- static void
- split_sections (bfd *abfd, struct bfd_link_info *info)
- {
- asection *original_sec;
- int nsecs = abfd->section_count;
- sanity_check (abfd);
- /* Look through all the original sections. */
- for (original_sec = abfd->sections;
- original_sec && nsecs;
- original_sec = original_sec->next, nsecs--)
- {
- int count = 0;
- unsigned int lines = 0;
- unsigned int relocs = 0;
- bfd_size_type sec_size = 0;
- struct bfd_link_order *l;
- struct bfd_link_order *p;
- bfd_vma vma = original_sec->vma;
- asection *cursor = original_sec;
- /* Count up the relocations and line entries to see if anything
- would be too big to fit. Accumulate section size too. */
- for (l = NULL, p = cursor->map_head.link_order; p != NULL; p = l->next)
- {
- unsigned int thislines = 0;
- unsigned int thisrelocs = 0;
- bfd_size_type thissize = 0;
- if (p->type == bfd_indirect_link_order)
- {
- asection *sec;
- sec = p->u.indirect.section;
- if (info->strip == strip_none
- || info->strip == strip_some)
- thislines = sec->lineno_count;
- if (bfd_link_relocatable (info))
- thisrelocs = sec->reloc_count;
- thissize = sec->size;
- }
- else if (bfd_link_relocatable (info)
- && (p->type == bfd_section_reloc_link_order
- || p->type == bfd_symbol_reloc_link_order))
- thisrelocs++;
- if (l != NULL
- && (thisrelocs + relocs >= config.split_by_reloc
- || thislines + lines >= config.split_by_reloc
- || (thissize + sec_size >= config.split_by_file))
- && !unsplittable_name (cursor->name))
- {
- /* Create a new section and put this link order and the
- following link orders into it. */
- bfd_vma shift_offset;
- asection *n;
- n = clone_section (abfd, cursor, original_sec->name, &count);
- /* Attach the link orders to the new section and snip
- them off from the old section. */
- n->map_head.link_order = p;
- n->map_tail.link_order = cursor->map_tail.link_order;
- cursor->map_tail.link_order = l;
- l->next = NULL;
- l = p;
- /* Change the size of the original section and
- update the vma of the new one. */
- dump ("before snip", cursor, n);
- shift_offset = p->offset;
- n->size = cursor->size - shift_offset;
- cursor->size = shift_offset;
- vma += shift_offset;
- n->lma = n->vma = vma;
- /* Run down the chain and change the output section to
- the right one, update the offsets too. */
- do
- {
- p->offset -= shift_offset;
- if (p->type == bfd_indirect_link_order)
- {
- p->u.indirect.section->output_section = n;
- p->u.indirect.section->output_offset = p->offset;
- }
- p = p->next;
- }
- while (p);
- dump ("after snip", cursor, n);
- cursor = n;
- relocs = thisrelocs;
- lines = thislines;
- sec_size = thissize;
- }
- else
- {
- l = p;
- relocs += thisrelocs;
- lines += thislines;
- sec_size += thissize;
- }
- }
- }
- sanity_check (abfd);
- }
- /* Call BFD to write out the linked file. */
- void
- ldwrite (void)
- {
- /* Reset error indicator, which can typically something like invalid
- format from opening up the .o files. */
- bfd_set_error (bfd_error_no_error);
- lang_clear_os_map ();
- lang_for_each_statement (build_link_order);
- if (config.split_by_reloc != (unsigned) -1
- || config.split_by_file != (bfd_size_type) -1)
- split_sections (link_info.output_bfd, &link_info);
- if (!bfd_final_link (link_info.output_bfd, &link_info))
- {
- /* If there was an error recorded, print it out. Otherwise assume
- an appropriate error message like unknown symbol was printed
- out. */
- if (bfd_get_error () != bfd_error_no_error)
- einfo (_("%F%P: final link failed: %E\n"));
- else
- xexit (1);
- }
- }
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