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lto-plugin.c: Include <hashtab.h>

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* lto-plugin.c: Include <hashtab.h>
        (sym_aux): Add next_conflict field to save conflict chains.
        (plugin_file_info): Add conflicts symtab.
        (parse_table_entry): Initialize aux->next_conflict.
        (process_symtab): Increment found.
        (dump_symtab): Add.
        (finish_conflict_resolution): Add.
        (free_symtab): Add.
        (write_resolution): Remove symbols loop and move into
        dump_symtab. Call dump_symtab for main symbol and conflicts table.
        Call free_symtab to free conflicts table.
        (SWAP): Add.
        (eq_sym): Add.
        (hash_sym): Add.
        (symbol_strength): Add.
        (resolve_conflicts): Add.
        (claim_file_handler): Add n variable. Check return value of
        process_symtab. Call resolve_conflicts.

From-SVN: r162915
This commit is contained in:
Andi Kleen 2010-08-05 14:25:45 +00:00 • committed by Andi Kleen
parent 2645f11a7c
commit d2c57fe97e
2 changed files with 242 additions and 9 deletions
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21
lto-plugin/ChangeLog
View file

@ -1,3 +1,24 @@
2010-08-05 Andi Kleen <ak@linux.intel.com>
* lto-plugin.c: Include <hashtab.h>
(sym_aux): Add next_conflict field to save conflict chains.
(plugin_file_info): Add conflicts symtab.
(parse_table_entry): Initialize aux->next_conflict.
(process_symtab): Increment found.
(dump_symtab): Add.
(finish_conflict_resolution): Add.
(free_symtab): Add.
(write_resolution): Remove symbols loop and move into
dump_symtab. Call dump_symtab for main symbol and conflicts table.
Call free_symtab to free conflicts table.
(SWAP): Add.
(eq_sym): Add.
(hash_sym): Add.
(symbol_strength): Add.
(resolve_conflicts): Add.
(claim_file_handler): Add n variable. Check return value of
process_symtab. Call resolve_conflicts.
2010-07-27 Andi Kleen <ak@linux.intel.com>
* lto-plugin.c (translate): Remove debug fprintf.

230
lto-plugin/lto-plugin.c
View file

@ -44,6 +44,7 @@ along with this program; see the file COPYING3. If not see
#include <sys/wait.h>
#include <stdbool.h>
#include <libiberty.h>
#include <hashtab.h>
/* The presence of gelf.h is checked by the toplevel configure script. */
#include <gelf.h>
@ -59,6 +60,7 @@ struct sym_aux
{
uint32_t slot;
unsigned id;
unsigned next_conflict;
};
struct plugin_symtab
@ -76,6 +78,7 @@ struct plugin_file_info
char *name;
void *handle;
struct plugin_symtab symtab;
struct plugin_symtab conflicts;
};
@ -183,6 +186,8 @@ parse_table_entry (char *p, struct ld_plugin_symbol *entry,
entry->resolution = LDPR_UNKNOWN;
aux->next_conflict = -1;
return p;
}
@ -246,7 +251,7 @@ process_symtab (Elf *elf, struct plugin_symtab *out)
if (s)
sscanf (s, ".%x", &out->id);
translate (elf_getdata (section, NULL), out);
found = 1;
found++;
}
}
return found;
@ -303,6 +308,82 @@ free_2 (void)
arguments_file_name = NULL;
}
/* Dump SYMTAB to resolution file F. */
static void
dump_symtab (FILE *f, struct plugin_symtab *symtab)
{
unsigned j;
for (j = 0; j < symtab->nsyms; j++)
{
uint32_t slot = symtab->aux[j].slot;
unsigned int resolution = symtab->syms[j].resolution;
assert (resolution != LDPR_UNKNOWN);
fprintf (f, "%d %x %s %s\n", slot, symtab->aux[j].id,
lto_resolution_str[resolution],
symtab->syms[j].name);
}
}
/* Finish the conflicts' resolution information after the linker resolved
the original symbols */
static void
finish_conflict_resolution (struct plugin_symtab *symtab,
struct plugin_symtab *conflicts)
{
int i, j;
if (conflicts->nsyms == 0)
return;
for (i = 0; i < symtab->nsyms; i++)
{
int resolution;
if (symtab->aux[i].next_conflict == -1)
continue;
switch (symtab->syms[i].def)
{
case LDPK_DEF:
case LDPK_COMMON: /* ??? */
resolution = LDPR_RESOLVED_IR;
break;
case LDPK_WEAKDEF:
resolution = LDPR_PREEMPTED_IR;
break;
case LDPK_UNDEF:
case LDPK_WEAKUNDEF:
resolution = symtab->syms[i].resolution;
break;
default:
assert (0);
}
assert (resolution != LDPR_UNKNOWN);
for (j = symtab->aux[i].next_conflict;
j != -1;
j = conflicts->aux[j].next_conflict)
conflicts->syms[j].resolution = resolution;
}
}
/* Free symbol table SYMTAB. */
static void
free_symtab (struct plugin_symtab *symtab)
{
free (symtab->syms);
symtab->syms = NULL;
free (symtab->aux);
symtab->aux = NULL;
}
/* Writes the relocations to disk. */
static void
@ -322,18 +403,17 @@ write_resolution (void)
struct plugin_file_info *info = &claimed_files[i];
struct plugin_symtab *symtab = &info->symtab;
struct ld_plugin_symbol *syms = symtab->syms;
unsigned j;
get_symbols (info->handle, symtab->nsyms, syms);
fprintf (f, "%s %d\n", info->name, info->symtab.nsyms);
finish_conflict_resolution (symtab, &info->conflicts);
for (j = 0; j < info->symtab.nsyms; j++)
fprintf (f, "%s %d\n", info->name, symtab->nsyms + info->conflicts.nsyms);
dump_symtab (f, symtab);
if (info->conflicts.nsyms)
{
uint32_t slot = symtab->aux[j].slot;
unsigned int resolution = syms[j].resolution;
fprintf (f, "%d %x %s %s\n", slot, symtab->aux[j].id,
lto_resolution_str[resolution], syms[j].name);
dump_symtab (f, &info->conflicts);
free_symtab (&info->conflicts);
}
}
fclose (f);
@ -550,6 +630,130 @@ cleanup_handler (void)
return LDPS_OK;
}
#define SWAP(type, a, b) \
do { type tmp_; tmp_ = (a); (a) = (b); (b) = tmp_; } while(0)
/* Compare two hash table entries */
static int eq_sym (const void *a, const void *b)
{
const struct ld_plugin_symbol *as = (const struct ld_plugin_symbol *)a;
const struct ld_plugin_symbol *bs = (const struct ld_plugin_symbol *)b;
return !strcmp (as->name, bs->name);
}
/* Hash a symbol */
static hashval_t hash_sym (const void *a)
{
const struct ld_plugin_symbol *as = (const struct ld_plugin_symbol *)a;
return htab_hash_string (as->name);
}
/* Determine how strong a symbol is */
static int symbol_strength (struct ld_plugin_symbol *s)
{
switch (s->def)
{
case LDPK_UNDEF:
case LDPK_WEAKUNDEF:
return 0;
case LDPK_WEAKDEF:
return 1;
default:
return 2;
}
}
/* In the ld -r case we can get dups in the LTO symbol tables, where
the same symbol can have different resolutions (e.g. undefined and defined).
We have to keep that in the LTO symbol tables, but the dups confuse
gold and then finally gcc by supplying incorrect resolutions.
Problem is that the main gold symbol table doesn't know about subids
and does not distingush the same symbols in different states.
So we drop duplicates from the linker visible symbol table
and keep them in a private table. Then later do own symbol
resolution for the duplicated based on the results for the
originals.
Then when writing out the resolution file readd the dropped symbols.
XXX how to handle common? */
static void
resolve_conflicts (struct plugin_symtab *t, struct plugin_symtab *conflicts)
{
htab_t symtab = htab_create (t->nsyms, hash_sym, eq_sym, NULL);
int i;
int out;
int outlen;
outlen = t->nsyms;
conflicts->syms = xmalloc (sizeof (struct ld_plugin_symbol) * outlen);
conflicts->aux = xmalloc (sizeof (struct sym_aux) * outlen);
/* Move all duplicate symbols into the auxillary conflicts table. */
out = 0;
for (i = 0; i < t->nsyms; i++)
{
struct ld_plugin_symbol *s = &t->syms[i];
struct sym_aux *aux = &t->aux[i];
void **slot;
slot = htab_find_slot (symtab, s, INSERT);
if (*slot != NULL)
{
int cnf;
struct ld_plugin_symbol *orig = (struct ld_plugin_symbol *)*slot;
struct sym_aux *orig_aux = &t->aux[orig - t->syms];
/* Always let the linker resolve the strongest symbol */
if (symbol_strength (orig) < symbol_strength (s))
{
SWAP (struct ld_plugin_symbol, *orig, *s);
SWAP (uint32_t, orig_aux->slot, aux->slot);
SWAP (unsigned, orig_aux->id, aux->id);
/* Don't swap conflict chain pointer */
}
/* Move current symbol into the conflicts table */
cnf = conflicts->nsyms++;
conflicts->syms[cnf] = *s;
conflicts->aux[cnf] = *aux;
aux = &conflicts->aux[cnf];
/* Update conflicts chain of the original symbol */
aux->next_conflict = orig_aux->next_conflict;
orig_aux->next_conflict = cnf;
continue;
}
/* Remove previous duplicates in the main table */
if (out < i)
{
t->syms[out] = *s;
t->aux[out] = *aux;
}
/* Put original into the hash table */
*slot = &t->syms[out];
out++;
}
assert (conflicts->nsyms <= outlen);
assert (conflicts->nsyms + out == t->nsyms);
t->nsyms = out;
htab_delete (symtab);
}
/* Callback used by gold to check if the plugin will claim FILE. Writes
the result in CLAIMED. */
@ -559,6 +763,7 @@ claim_file_handler (const struct ld_plugin_input_file *file, int *claimed)
enum ld_plugin_status status;
Elf *elf;
struct plugin_file_info lto_file;
int n;
memset (&lto_file, 0, sizeof (struct plugin_file_info));
@ -597,9 +802,16 @@ claim_file_handler (const struct ld_plugin_input_file *file, int *claimed)
*claimed = 0;
if (!elf || !process_symtab (elf, &lto_file.symtab))
if (!elf)
goto err;
n = process_symtab (elf, &lto_file.symtab);
if (n == 0)
goto err;
if (n > 1)
resolve_conflicts (&lto_file.symtab, &lto_file.conflicts);
status = add_symbols (file->handle, lto_file.symtab.nsyms,
lto_file.symtab.syms);
check (status == LDPS_OK, LDPL_FATAL, "could not add symbols");