1/* Emulation code used by all ELF targets.
2   Copyright (C) 1991-2020 Free Software Foundation, Inc.
3
4   This file is part of the GNU Binutils.
5
6   This program is free software; you can redistribute it and/or modify
7   it under the terms of the GNU General Public License as published by
8   the Free Software Foundation; either version 3 of the License, or
9   (at your option) any later version.
10
11   This program is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   GNU General Public License for more details.
15
16   You should have received a copy of the GNU General Public License
17   along with this program; if not, write to the Free Software
18   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
19   MA 02110-1301, USA.  */
20
21#include "sysdep.h"
22#include "bfd.h"
23#include "bfdlink.h"
24#include "ctf-api.h"
25#include "ld.h"
26#include "ldmain.h"
27#include "ldmisc.h"
28#include "ldexp.h"
29#include "ldlang.h"
30#include "elf-bfd.h"
31#include "ldelfgen.h"
32
33void
34ldelf_map_segments (bfd_boolean need_layout)
35{
36  int tries = 10;
37
38  do
39    {
40      lang_relax_sections (need_layout);
41      need_layout = FALSE;
42
43      if (link_info.output_bfd->xvec->flavour == bfd_target_elf_flavour
44	  && !bfd_link_relocatable (&link_info))
45	{
46	  bfd_size_type phdr_size;
47
48	  phdr_size = elf_program_header_size (link_info.output_bfd);
49	  /* If we don't have user supplied phdrs, throw away any
50	     previous linker generated program headers.  */
51	  if (lang_phdr_list == NULL)
52	    elf_seg_map (link_info.output_bfd) = NULL;
53	  if (!_bfd_elf_map_sections_to_segments (link_info.output_bfd,
54						  &link_info))
55	    einfo (_("%F%P: map sections to segments failed: %E\n"));
56
57	  if (phdr_size != elf_program_header_size (link_info.output_bfd))
58	    {
59	      if (tries > 6)
60		/* The first few times we allow any change to
61		   phdr_size .  */
62		need_layout = TRUE;
63	      else if (phdr_size
64		       < elf_program_header_size (link_info.output_bfd))
65		/* After that we only allow the size to grow.  */
66		need_layout = TRUE;
67	      else
68		elf_program_header_size (link_info.output_bfd) = phdr_size;
69	    }
70	}
71    }
72  while (need_layout && --tries);
73
74  if (tries == 0)
75    einfo (_("%F%P: looping in map_segments"));
76}
77
78/* We want to emit CTF early if and only if we are not targetting ELF with this
79   invocation.  */
80
81int
82ldelf_emit_ctf_early (void)
83{
84  if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour)
85    return 0;
86  return 1;
87}
88
89/* Callbacks used to map from bfd types to libctf types, under libctf's
90   control.  */
91
92struct ctf_strsym_iter_cb_arg
93{
94  struct elf_sym_strtab *syms;
95  bfd_size_type symcount;
96  struct elf_strtab_hash *symstrtab;
97  size_t next_i;
98  size_t next_idx;
99};
100
101/* Return strings from the strtab to libctf, one by one.  Returns NULL when
102   iteration is complete.  */
103
104static const char *
105ldelf_ctf_strtab_iter_cb (uint32_t *offset, void *arg_)
106{
107  bfd_size_type off;
108  const char *ret;
109
110  struct ctf_strsym_iter_cb_arg *arg =
111    (struct ctf_strsym_iter_cb_arg *) arg_;
112
113  /* There is no zeroth string.  */
114  if (arg->next_i == 0)
115    arg->next_i = 1;
116
117  if (arg->next_i >= _bfd_elf_strtab_len (arg->symstrtab))
118    {
119      arg->next_i = 0;
120      return NULL;
121    }
122
123  ret = _bfd_elf_strtab_str (arg->symstrtab, arg->next_i++, &off);
124  *offset = off;
125
126  /* If we've overflowed, we cannot share any further strings: the CTF
127     format cannot encode strings with such high offsets.  */
128  if (*offset != off)
129    return NULL;
130
131  return ret;
132}
133
134/* Return symbols from the symbol table to libctf, one by one.  We assume (and
135   assert) that the symbols in the elf_link_hash_table are in strictly ascending
136   order, and that none will be added in between existing ones.  Returns NULL
137   when iteration is complete.  */
138
139static struct ctf_link_sym *
140ldelf_ctf_symbols_iter_cb (struct ctf_link_sym *dest,
141					   void *arg_)
142{
143  struct ctf_strsym_iter_cb_arg *arg =
144    (struct ctf_strsym_iter_cb_arg *) arg_;
145
146  if (arg->next_i > arg->symcount)
147    {
148      arg->next_i = 0;
149      arg->next_idx = 0;
150      return NULL;
151    }
152
153  ASSERT (arg->syms[arg->next_i].dest_index == arg->next_idx);
154  dest->st_name = _bfd_elf_strtab_str (arg->symstrtab, arg->next_i, NULL);
155  dest->st_shndx = arg->syms[arg->next_i].sym.st_shndx;
156  dest->st_type = ELF_ST_TYPE (arg->syms[arg->next_i].sym.st_info);
157  dest->st_value = arg->syms[arg->next_i].sym.st_value;
158  arg->next_i++;
159  return dest;
160}
161
162void
163ldelf_examine_strtab_for_ctf
164  (struct ctf_file *ctf_output, struct elf_sym_strtab *syms,
165   bfd_size_type symcount, struct elf_strtab_hash *symstrtab)
166{
167  struct ctf_strsym_iter_cb_arg args = { syms, symcount, symstrtab,
168					  0, 0 };
169   if (!ctf_output)
170     return;
171
172   if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour
173       && !bfd_link_relocatable (&link_info))
174    {
175      if (ctf_link_add_strtab (ctf_output, ldelf_ctf_strtab_iter_cb,
176			       &args) < 0)
177	einfo (_("%F%P: warning: CTF strtab association failed; strings will "
178		 "not be shared: %s\n"),
179	       ctf_errmsg (ctf_errno (ctf_output)));
180
181      if (ctf_link_shuffle_syms (ctf_output, ldelf_ctf_symbols_iter_cb,
182				 &args) < 0)
183	einfo (_("%F%P: warning: CTF symbol shuffling failed; slight space "
184		 "cost: %s\n"), ctf_errmsg (ctf_errno (ctf_output)));
185    }
186}
187