gcc/lto-plugin/lto-symtab.c

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/* Program to read the IL symbol table.
Copyright (C) 2008-2017 Free Software Foundation, Inc.
Contributed by Rafael Avila de Espindola (espindola@google.com).
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 <fcntl.h>
#include <assert.h>
#include <dlfcn.h>
#include <stdio.h>
#include <inttypes.h>
#include <stdlib.h>
#include <string.h>
#include "plugin-api.h"
#include "../gcc/lto/common.h"
/* The presence of gelf.h is checked by the toplevel configure script. */
# include <gelf.h>
static ld_plugin_claim_file_handler claim_file_handler;
static ld_plugin_all_symbols_read_handler all_symbols_read_handler;
static ld_plugin_cleanup_handler cleanup_handler;
static void *plugin_handle;
struct file_handle {
unsigned nsyms;
struct ld_plugin_symbol *syms;
};
static struct file_handle **all_file_handles = NULL;
static unsigned int num_file_handles;
/* Write NSYMS symbols from file HANDLE in SYMS. */
static enum ld_plugin_status
get_symbols (const void *handle, int nsyms, struct ld_plugin_symbol *syms)
{
unsigned i;
struct file_handle *h = (struct file_handle *) handle;
assert (h->nsyms == nsyms);
for (i = 0; i < nsyms; i++)
syms[i] = h->syms[i];
return LDPS_OK;
}
/* Register HANDLER as the callback for notifying the plugin that all symbols
have been read. */
static enum ld_plugin_status
register_all_symbols_read (ld_plugin_all_symbols_read_handler handler)
{
all_symbols_read_handler = handler;
return LDPS_OK;
}
/* Register HANDLER as the callback for claiming a file. */
static enum ld_plugin_status
register_claim_file(ld_plugin_claim_file_handler handler)
{
claim_file_handler = handler;
return LDPS_OK;
}
/* Register HANDLER as the callback to removing temporary files. */
static enum ld_plugin_status
register_cleanup (ld_plugin_cleanup_handler handler)
{
cleanup_handler = handler;
return LDPS_OK;
}
/* For a file identified by HANDLE, add NSYMS symbols from SYMS. */
static enum ld_plugin_status
add_symbols (void *handle, int nsyms,
const struct ld_plugin_symbol *syms)
{
int i;
struct file_handle *h = (struct file_handle *) handle;
h->nsyms = nsyms;
h->syms = calloc (nsyms, sizeof (struct ld_plugin_symbol));
assert (h->syms);
for (i = 0; i < nsyms; i++)
{
h->syms[i] = syms[i];
h->syms[i].name = strdup (h->syms[i].name);
if (h->syms[i].version)
h->syms[i].version = strdup (h->syms[i].version);
if (h->syms[i].comdat_key)
h->syms[i].comdat_key = strdup (h->syms[i].comdat_key);
}
return LDPS_OK;
}
struct ld_plugin_tv tv[] = {
{LDPT_REGISTER_CLAIM_FILE_HOOK,
{.tv_register_claim_file = register_claim_file}
},
{LDPT_ADD_SYMBOLS,
{.tv_add_symbols = add_symbols}
},
{LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK,
{.tv_register_all_symbols_read = register_all_symbols_read}
},
{LDPT_GET_SYMBOLS,
{.tv_get_symbols = get_symbols}
},
{LDPT_REGISTER_CLEANUP_HOOK,
{.tv_register_cleanup = register_cleanup}
},
{0, {0}}
};
/* Load a plugin from a file named NAME. */
static void
load_plugin (const char *name)
{
ld_plugin_onload onload;
plugin_handle = dlopen (name, RTLD_LAZY);
assert (plugin_handle != NULL);
onload = dlsym (plugin_handle, "onload");
assert (onload);
onload (tv);
assert (claim_file_handler);
}
/* Send object to the plugin. The file (archive or object) name is NAME.
FD is an open file descriptor. The object data starts at OFFSET and is
FILESIZE bytes long. */
static void
register_object (const char *name, int fd, off_t offset, off_t filesize)
{
int claimed;
struct ld_plugin_input_file file;
void *handle;
num_file_handles++;
all_file_handles = realloc (all_file_handles, num_file_handles
* sizeof (struct file_handle *));
assert (all_file_handles);
all_file_handles[num_file_handles - 1] = calloc (1,
sizeof (struct file_handle));
handle = all_file_handles[num_file_handles - 1];
assert (handle);
file.name = (char *) name;
file.fd = fd;
file.offset = offset;
file.filesize = filesize;
file.handle = handle;
claim_file_handler (&file, &claimed);
}
/* Send file named NAME to the plugin. */
static void
register_file (const char *name)
{
int fd = open (name, O_RDONLY);
Elf *elf;
assert (fd >= 0);
elf = elf_begin (fd, ELF_C_READ, NULL);
assert (elf);
Elf_Kind kind = elf_kind (elf);
assert (kind == ELF_K_ELF || kind == ELF_K_AR);
if (kind == ELF_K_AR)
{
Elf *member = elf_begin (fd, ELF_C_READ, elf);
while (member)
{
Elf_Arhdr *h = elf_getarhdr (member);
assert (h);
if (h->ar_name[0] != '/')
{
off_t offset = elf_getbase (member);
register_object (name, fd, offset, h->ar_size);
}
Elf_Cmd cmd = elf_next (member);
elf_end (member);
member = elf_begin (fd, cmd, elf);
}
}
else /* Single File */
register_object (name, fd, 0, 0);
elf_end (elf);
}
/* Fake symbol resolution for testing. */
static void
resolve (void)
{
unsigned j;
for (j = 0; j < num_file_handles; j++)
{
struct file_handle *handle = all_file_handles[j];
unsigned int nsyms = handle->nsyms;
struct ld_plugin_symbol *syms = handle->syms;
unsigned i;
for (i = 0; i < nsyms; i++)
{
switch (syms[i].def)
{
case LDPK_DEF:
case LDPK_WEAKDEF:
case LDPK_COMMON:
syms[i].resolution = LDPR_PREVAILING_DEF;
break;
case LDPK_UNDEF:
case LDPK_WEAKUNDEF:
syms[i].resolution = LDPR_RESOLVED_IR;
break;
}
}
}
}
/* Print all symbol information. */
static void
print (void)
{
unsigned j;
for (j = 0; j < num_file_handles; j++)
{
struct file_handle *handle = all_file_handles[j];
unsigned int nsyms = handle->nsyms;
struct ld_plugin_symbol *syms = handle->syms;
unsigned i;
for (i = 0; i < nsyms; i++)
{
printf("name: %s; ", syms[i].name);
if (syms[i].version)
printf("version: %s;", syms[i].version);
else
printf("not versioned; ");
printf("kind: %s; ", lto_kind_str[syms[i].def]);
printf("visibility: %s; ", lto_visibility_str[syms[i].visibility]);
printf("size: %" PRId64 "; ", syms[i].size);
if (syms[i].comdat_key)
printf("comdat_key: %s; ", syms[i].comdat_key);
else
printf("no comdat_key; ");
printf ("resolution: %s\n", lto_resolution_str[syms[i].resolution]);
}
}
}
/* Unload the plugin. */
static void
unload_plugin (void)
{
unsigned err = dlclose (plugin_handle);
assert (err == 0);
claim_file_handler = 0;
all_symbols_read_handler = 0;
}
/* Free all memory allocated by us that hasn't been freed yet. */
static void
free_all (void)
{
unsigned j;
for (j = 0; j < num_file_handles; j++)
{
struct file_handle *handle = all_file_handles[j];
unsigned int nsyms = handle->nsyms;
struct ld_plugin_symbol *syms = handle->syms;
unsigned i;
for (i = 0; i < nsyms; i++)
{
free (syms[i].name);
syms[i].name = 0;
if (syms[i].version)
{
free (syms[i].version);
syms[i].version = 0;
}
if (syms[i].comdat_key)
{
free (syms[i].comdat_key);
syms[i].comdat_key = 0;
}
}
free (syms);
handle->syms = NULL;
handle->nsyms = 0;
free (all_file_handles[j]);
all_file_handles[j] = NULL;
}
free (all_file_handles);
all_file_handles = NULL;
num_file_handles = 0;
}
int
main(int argc, char *argv[])
{
const char *plugin;
unsigned int i;
assert (argc >= 3);
plugin = argv[1];
load_plugin (plugin);
for (i = 2; i < argc; i++)
register_file (argv[i]);
resolve ();
print ();
all_symbols_read_handler ();
free_all ();
cleanup_handler ();
unload_plugin ();
return 0;
}