c9db653c8d
When CONFIG_SYMTAB_ORDEREDBYNAME is selected most code will use the ordered search function. When it is not selected no code will use the ordered search function. This change merges the two functions and varies its behaviour based on the config setting, such that all callers can simply call the one search function and get the best behaviour. An additional configuration option allows leading underscores to be stripped from symbols being relocated in loaded objects. This allows toolchains which prefix C symbol with underscores to make loadable ELF objects.
126 lines
3.7 KiB
C
126 lines
3.7 KiB
C
/****************************************************************************
|
|
* libs/libc/symtab/symtab_findbyname.c
|
|
*
|
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
|
* contributor license agreements. See the NOTICE file distributed with
|
|
* this work for additional information regarding copyright ownership. The
|
|
* ASF licenses this file to you under the Apache License, Version 2.0 (the
|
|
* "License"); you may not use this file except in compliance with the
|
|
* License. You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
* License for the specific language governing permissions and limitations
|
|
* under the License.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
|
|
#include <string.h>
|
|
#include <debug.h>
|
|
#include <assert.h>
|
|
#include <errno.h>
|
|
|
|
#include <nuttx/symtab.h>
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: symtab_findbyname
|
|
*
|
|
* Description:
|
|
* Find the symbol in the symbol table with the matching name.
|
|
* This version assumes that table is not ordered with respect to symbol
|
|
* name and, hence, access time will be linear with respect to nsyms.
|
|
*
|
|
* Returned Value:
|
|
* A reference to the symbol table entry if an entry with the matching
|
|
* name is found; NULL is returned if the entry is not found.
|
|
*
|
|
****************************************************************************/
|
|
|
|
FAR const struct symtab_s *
|
|
symtab_findbyname(FAR const struct symtab_s *symtab,
|
|
FAR const char *name, int nsyms)
|
|
{
|
|
#ifdef CONFIG_SYMTAB_ORDEREDBYNAME
|
|
int low = 0;
|
|
int high = nsyms - 1;
|
|
int mid;
|
|
int cmp;
|
|
#endif
|
|
|
|
#ifdef CONFIG_SYMTAB_DECORATED
|
|
if (name[0] == '_')
|
|
{
|
|
name++;
|
|
}
|
|
#endif
|
|
|
|
DEBUGASSERT(symtab != NULL && name != NULL);
|
|
|
|
#ifdef CONFIG_SYMTAB_ORDEREDBYNAME
|
|
while (low < high)
|
|
{
|
|
/* Compare the name to the one in the middle. (or just below
|
|
* the middle in the case where one is even and one is odd).
|
|
*/
|
|
|
|
mid = (low + high) >> 1;
|
|
cmp = strcmp(name, symtab[mid].sym_name);
|
|
if (cmp < 0)
|
|
{
|
|
/* name < symtab[mid].sym_name
|
|
*
|
|
* NOTE: Because of truncation in the calculation of 'mid'.
|
|
* 'mid' could be equal to 'low'
|
|
*/
|
|
|
|
high = mid > low ? mid - 1 : low;
|
|
}
|
|
else if (cmp > 0)
|
|
{
|
|
/* name > symtab[mid].sym_name */
|
|
|
|
low = mid + 1;
|
|
}
|
|
else
|
|
{
|
|
/* symtab[mid].sym_name == name */
|
|
|
|
return &symtab[mid];
|
|
}
|
|
}
|
|
|
|
/* low == high... One final check. We might not have actually tested
|
|
* the final symtab[] name.
|
|
*
|
|
* Example: Only the last pass through loop, suppose low = 1, high = 2,
|
|
* mid = 1, and symtab[high].sym_name == name. Then we would get here
|
|
* with low = 2, high = 2, but symtab[2].sym_name was never tested.
|
|
*/
|
|
|
|
return strcmp(name, symtab[low].sym_name) == 0 ? &symtab[low] : NULL;
|
|
#else
|
|
for (; nsyms > 0; symtab++, nsyms--)
|
|
{
|
|
if (strcmp(name, symtab->sym_name) == 0)
|
|
{
|
|
return symtab;
|
|
}
|
|
}
|
|
|
|
return NULL;
|
|
#endif
|
|
}
|