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[PATCH] Add STB_SECONDARY support
- From: "H.J. Lu" <hongjiu dot lu at intel dot com>
- To: GNU C Library <libc-alpha at sourceware dot org>
- Date: Sat, 30 Jun 2012 14:22:50 -0700
- Subject: [PATCH] Add STB_SECONDARY support
- Reply-to: "H.J. Lu" <hjl dot tools at gmail dot com>
Hi,
This patch adds STB_SECONDARY support to ld.so. STB_SECONDARY symbols
behave exactly the same as STB_WEAK symbols when LD_DYNAMIC_WEAK is set.
OK to install after 2.17 is open?
Thanks.
H.J.
---
2012-06-30 H.J. Lu <hongjiu.lu@intel.com>
* elf/dl-addr.c (determine_info): Also check STB_SECONDARY.
* elf/dl-lookup.c (do_lookup_x): Handle STB_SECONDARY.
(_dl_lookup_symbol_x): Likewise.
* elf/sprof.c (read_symbols): Likewise.
* elf/elf.h (STB_SECONDARY): New.
diff --git a/elf/dl-addr.c b/elf/dl-addr.c
index 498faf1..dc2aca3 100644
--- a/elf/dl-addr.c
+++ b/elf/dl-addr.c
@@ -87,7 +87,8 @@ determine_info (const ElfW(Addr) addr, struct link_map *match, Dl_info *info,
for (; (void *) symtab < (void *) symtabend; ++symtab)
if ((ELFW(ST_BIND) (symtab->st_info) == STB_GLOBAL
- || ELFW(ST_BIND) (symtab->st_info) == STB_WEAK)
+ || ELFW(ST_BIND) (symtab->st_info) == STB_WEAK
+ || ELFW(ST_BIND) (symtab->st_info) == STB_SECONDARY)
&& ELFW(ST_TYPE) (symtab->st_info) != STT_TLS
&& (symtab->st_shndx != SHN_UNDEF
|| symtab->st_value != 0)
diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c
index a2a699b..877eb76 100644
--- a/elf/dl-lookup.c
+++ b/elf/dl-lookup.c
@@ -285,10 +285,15 @@ do_lookup_x (const char *undef_name, uint_fast32_t new_hash,
found_it:
switch (__builtin_expect (ELFW(ST_BIND) (sym->st_info), STB_GLOBAL))
{
+ case STB_SECONDARY:
+ /* Secondary definition. Use this value if we don't find
+ another. */
+ goto dynamic_weak;
case STB_WEAK:
/* Weak definition. Use this value if we don't find another. */
if (__builtin_expect (GLRO(dl_dynamic_weak), 0))
{
+dynamic_weak:
if (! result->s)
{
result->s = sym;
@@ -768,7 +773,9 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
if (__builtin_expect (current_value.s == NULL, 0))
{
- if ((*ref == NULL || ELFW(ST_BIND) ((*ref)->st_info) != STB_WEAK)
+ if ((*ref == NULL
+ || (ELFW(ST_BIND) ((*ref)->st_info) != STB_WEAK
+ && ELFW(ST_BIND) ((*ref)->st_info) != STB_SECONDARY))
&& skip_map == NULL
&& !(GLRO(dl_debug_mask) & DL_DEBUG_UNUSED))
{
diff --git a/elf/elf.h b/elf/elf.h
index 6522ea6..9802f8a 100644
--- a/elf/elf.h
+++ b/elf/elf.h
@@ -444,7 +444,8 @@ typedef struct
#define STB_LOCAL 0 /* Local symbol */
#define STB_GLOBAL 1 /* Global symbol */
#define STB_WEAK 2 /* Weak symbol */
-#define STB_NUM 3 /* Number of defined types. */
+#define STB_SECONDARY 3 /* Secondary symbol */
+#define STB_NUM 4 /* Number of defined types. */
#define STB_LOOS 10 /* Start of OS-specific */
#define STB_GNU_UNIQUE 10 /* Unique symbol. */
#define STB_HIOS 12 /* End of OS-specific */
diff --git a/elf/sprof.c b/elf/sprof.c
index 2097d31..2325180 100644
--- a/elf/sprof.c
+++ b/elf/sprof.c
@@ -1078,7 +1078,8 @@ read_symbols (struct shobj *shobj)
newsym->name = &shobj->strtab[sym->st_name];
newsym->addr = sym->st_value;
newsym->size = sym->st_size;
- newsym->weak = ELFW(ST_BIND) (sym->st_info) == STB_WEAK;
+ newsym->weak = (ELFW(ST_BIND) (sym->st_info) == STB_SECONDARY
+ || ELFW(ST_BIND) (sym->st_info) == STB_WEAK);
newsym->hidden = (ELFW(ST_VISIBILITY) (sym->st_other)
!= STV_DEFAULT);
newsym->ticks = 0;
@@ -1136,7 +1137,8 @@ read_symbols (struct shobj *shobj)
newsym->name = &strtab[symtab->st_name];
newsym->addr = symtab->st_value;
newsym->size = symtab->st_size;
- newsym->weak = ELFW(ST_BIND) (symtab->st_info) == STB_WEAK;
+ newsym->weak = (ELFW(ST_BIND) (symtab->st_info) == STB_SECONDARY
+ || ELFW(ST_BIND) (symtab->st_info) == STB_WEAK);
newsym->hidden = (ELFW(ST_VISIBILITY) (symtab->st_other)
!= STV_DEFAULT);
newsym->ticks = 0;
--
1.7.10.2