xref: /third_party/elfutils/libasm/asm_newsym.c (revision da0c48c4)
1/* Define new symbol for current position in given section.
2   Copyright (C) 2002, 2005, 2016, 2017 Red Hat, Inc.
3   This file is part of elfutils.
4   Written by Ulrich Drepper <drepper@redhat.com>, 2002.
5
6   This file is free software; you can redistribute it and/or modify
7   it under the terms of either
8
9     * the GNU Lesser General Public License as published by the Free
10       Software Foundation; either version 3 of the License, or (at
11       your option) any later version
12
13   or
14
15     * the GNU General Public License as published by the Free
16       Software Foundation; either version 2 of the License, or (at
17       your option) any later version
18
19   or both in parallel, as here.
20
21   elfutils is distributed in the hope that it will be useful, but
22   WITHOUT ANY WARRANTY; without even the implied warranty of
23   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
24   General Public License for more details.
25
26   You should have received copies of the GNU General Public License and
27   the GNU Lesser General Public License along with this program.  If
28   not, see <http://www.gnu.org/licenses/>.  */
29
30#ifdef HAVE_CONFIG_H
31# include <config.h>
32#endif
33
34#include <inttypes.h>
35#include <stdio.h>
36#include <stdlib.h>
37#include <string.h>
38
39#include <libasmP.h>
40#include <system.h>
41
42
43AsmSym_t *
44asm_newsym (AsmScn_t *asmscn, const char *name, GElf_Xword size,
45	    int type, int binding)
46{
47/* We don't really expect labels with many digits, but in theory it could
48   be 10 digits (plus ".L" and a zero terminator).  */
49#define TEMPSYMLEN 13
50  char tempsym[TEMPSYMLEN];
51  AsmSym_t *result;
52
53  if (asmscn == NULL)
54    /* Something went wrong before.  */
55    return NULL;
56
57  /* Generate a temporary symbol if necessary.  */
58  if (name == NULL)
59    {
60      /* If a local symbol name is created the symbol better have
61	 local binding.  */
62      if (binding != STB_LOCAL)
63	{
64	  __libasm_seterrno (ASM_E_INVALID);
65	  return NULL;
66	}
67
68      // XXX This requires getting the format from the machine backend.  */
69      snprintf (tempsym, TEMPSYMLEN, ".L%07u", asmscn->ctx->tempsym_count++);
70
71      name = tempsym;
72    }
73
74  size_t name_len = strlen (name) + 1;
75
76  result = malloc (sizeof (AsmSym_t) + name_len);
77  if (result == NULL)
78    return NULL;
79
80  rwlock_wrlock (asmscn->ctx->lock);
81
82  result->scn = asmscn;
83  result->offset = asmscn->offset;
84  result->size = size;
85  result->type = type;
86  result->binding = binding;
87  result->symidx = 0;
88  result->strent = dwelf_strtab_add (asmscn->ctx->symbol_strtab,
89				     memcpy (result + 1, name, name_len));
90
91  if (unlikely (asmscn->ctx->textp))
92    {
93      /* We are only interested in the name and don't need to know whether
94	 it is a local name or not.  */
95      /* First print the binding pseudo-op.  */
96      if (binding == STB_GLOBAL)
97	fprintf (asmscn->ctx->out.file, "\t.globl\t%s\n", name);
98      else if (binding == STB_WEAK)
99	fprintf (asmscn->ctx->out.file, "\t.weak\t%s\n", name);
100
101      /* Next the symbol type.  */
102      if (type == STT_OBJECT)
103	fprintf (asmscn->ctx->out.file, "\t.type\t%s,@object\n", name);
104      else if (type == STT_FUNC)
105	fprintf (asmscn->ctx->out.file, "\t.type\t%s,@function\n", name);
106
107      /* Finally the size and the label.  */
108      fprintf (asmscn->ctx->out.file, "\t.size\t%s,%" PRIuMAX "\n%s:\n",
109	       name, (uintmax_t) size, name);
110    }
111  else
112    {
113      /* Put the symbol in the hash table so that we can later find it.  */
114      if (asm_symbol_tab_insert (&asmscn->ctx->symbol_tab, elf_hash (name),
115				 result) != 0)
116	{
117	  /* The symbol already exists.  */
118	  __libasm_seterrno (ASM_E_DUPLSYM);
119	  /* Note that we can free the entry since there must be no
120	     reference in the string table to the string.  We can only
121	     fail to insert the symbol into the symbol table if there
122	     is already a symbol with this name.  In this case the
123	     dwelf_strtab_add function would use the previously provided
124	     name.  */
125	  free (result);
126	  result = NULL;
127	}
128      else if (name != tempsym && asm_emit_symbol_p (name))
129	/* Only count non-private symbols.  */
130	++asmscn->ctx->nsymbol_tab;
131    }
132
133  rwlock_unlock (asmscn->ctx->lock);
134
135  return result;
136}
137