PATCH: Add PROVIDE_HIDDEN
H. J. Lu
hjl@lucon.org
Thu Aug 4 18:58:00 GMT 2005
On Thu, Aug 04, 2005 at 10:41:24AM -0700, H. J. Lu wrote:
> On Thu, Aug 04, 2005 at 03:50:37PM +0930, Alan Modra wrote:
> > Now that we have stripping of empty output sections, even when they
> > contain symbols, a lot of special purpose code can be removed. Simply
> > defining symbols in the linker script should work. This patch does
> > that and also fixes some cases where PowerPC SDA relocs were
> > mishandled.
> >
>
> There is one problem. The linker provided symbols used to hidden, now
> they are global. It is a very bad when some bound symbols have to
> be provided for DSOs. I should we should make all linker provided
> symbol hidden for ELF.
>
>
This patch adds PROVIDE_HIDDEN.
H.J.
-------------- next part --------------
bfd/
2005-08-04 H.J. Lu <hongjiu.lu@intel.com>
* bfd.c (bfd_hide_symbol): New.
* bfd-in2.h: Regenerated.
ld/
2005-08-04 H.J. Lu <hongjiu.lu@intel.com>
* ld.texinfo: Document PROVIDE_HIDDEN.
* ldexp.c (exp_fold_tree_1): Hide a provided symbol if asked.
(exp_provide): Add and set hidden.
* ldexp.h (etree_type): Add hidden to assign.
* ldgram.y (PROVIDE_HIDDEN): New.
* ldlex.l (PROVIDE_HIDDEN): Likewise.
* scripttempl/elf.sc: Use PROVIDE_HIDDEN on array bound
symbols.
--- binutils/bfd/bfd.c.hidden 2005-06-06 08:54:38.000000000 -0700
+++ binutils/bfd/bfd.c 2005-08-04 11:32:16.211121884 -0700
@@ -1508,3 +1508,29 @@ bfd_preserve_finish (bfd *abfd ATTRIBUTE
objalloc. */
bfd_hash_table_free (&preserve->section_htab);
}
+
+/*
+FUNCTION
+ bfd_hide_symbol
+
+SYNOPSIS
+ void bfd_hide_symbol (bfd *,
+ struct bfd_link_info *,
+ struct bfd_link_hash_entry *,
+ bfd_boolean);
+
+DESCRIPTION
+ This function hides a symbol so that it won't be exported.
+
+*/
+
+void
+bfd_hide_symbol (bfd *abfd,
+ struct bfd_link_info *link_info,
+ struct bfd_link_hash_entry *h,
+ bfd_boolean force_local)
+{
+ if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
+ (get_elf_backend_data (abfd)->elf_backend_hide_symbol)
+ (link_info, (struct elf_link_hash_entry *) h, force_local);
+}
--- binutils/ld/ldexp.c.hidden 2005-06-09 09:14:32.000000000 -0700
+++ binutils/ld/ldexp.c 2005-08-04 11:34:54.774025359 -0700
@@ -740,6 +740,8 @@ exp_fold_tree_1 (etree_type *tree)
defined by some object. */
break;
}
+ if (tree->assign.hidden)
+ bfd_hide_symbol (output_bfd, &link_info, h, TRUE);
}
exp_fold_tree_1 (tree->assign.src);
@@ -884,7 +886,7 @@ exp_assop (int code, const char *dst, et
/* Handle PROVIDE. */
etree_type *
-exp_provide (const char *dst, etree_type *src)
+exp_provide (const char *dst, etree_type *src, bfd_boolean hidden)
{
etree_type *n;
@@ -893,6 +895,7 @@ exp_provide (const char *dst, etree_type
n->assign.type.node_class = etree_provide;
n->assign.src = src;
n->assign.dst = dst;
+ n->assign.hidden = hidden;
return n;
}
--- binutils/ld/ldexp.h.hidden 2005-06-09 09:14:32.000000000 -0700
+++ binutils/ld/ldexp.h 2005-08-04 11:16:03.433223155 -0700
@@ -63,6 +63,7 @@ typedef union etree_union {
node_type type;
const char *dst;
union etree_union *src;
+ bfd_boolean hidden;
} assign;
struct {
node_type type;
@@ -165,7 +166,7 @@ etree_type *exp_nameop
etree_type *exp_assop
(int, const char *, etree_type *);
etree_type *exp_provide
- (const char *, etree_type *);
+ (const char *, etree_type *, bfd_boolean);
etree_type *exp_assert
(etree_type *, const char *);
void exp_print_tree
--- binutils/ld/ldgram.y.hidden 2005-07-24 19:31:17.000000000 -0700
+++ binutils/ld/ldgram.y 2005-08-04 11:14:04.519794108 -0700
@@ -142,7 +142,7 @@ static int error_index;
%token STARTUP HLL SYSLIB FLOAT NOFLOAT NOCROSSREFS
%token ORIGIN FILL
%token LENGTH CREATE_OBJECT_SYMBOLS INPUT GROUP OUTPUT CONSTRUCTORS
-%token ALIGNMOD AT SUBALIGN PROVIDE AS_NEEDED
+%token ALIGNMOD AT SUBALIGN PROVIDE PROVIDE_HIDDEN AS_NEEDED
%type <token> assign_op atype attributes_opt sect_constraint
%type <name> filename
%token CHIP LIST SECT ABSOLUTE LOAD NEWLINE ENDWORD ORDER NAMEWORD ASSERT_K
@@ -648,7 +648,11 @@ assignment:
}
| PROVIDE '(' NAME '=' mustbe_exp ')'
{
- lang_add_assignment (exp_provide ($3, $5));
+ lang_add_assignment (exp_provide ($3, $5, FALSE));
+ }
+ | PROVIDE_HIDDEN '(' NAME '=' mustbe_exp ')'
+ {
+ lang_add_assignment (exp_provide ($3, $5, TRUE));
}
;
--- binutils/ld/ldlex.l.hidden 2005-05-16 11:04:40.000000000 -0700
+++ binutils/ld/ldlex.l 2005-08-04 11:34:11.716111896 -0700
@@ -313,6 +313,7 @@ V_IDENTIFIER [*?.$_a-zA-Z\[\]\-\!\^\\]([
<EXPRESSION,BOTH,SCRIPT>"AT" { RTOKEN(AT);}
<EXPRESSION,BOTH,SCRIPT>"SUBALIGN" { RTOKEN(SUBALIGN);}
<EXPRESSION,BOTH,SCRIPT>"PROVIDE" { RTOKEN(PROVIDE); }
+<EXPRESSION,BOTH,SCRIPT>"PROVIDE_HIDDEN" { RTOKEN(PROVIDE_HIDDEN); }
<EXPRESSION,BOTH,SCRIPT>"KEEP" { RTOKEN(KEEP); }
<EXPRESSION,BOTH,SCRIPT>"EXCLUDE_FILE" { RTOKEN(EXCLUDE_FILE); }
<MRI>"#".*\n? { ++ lineno; }
--- binutils/ld/scripttempl/elf.sc.hidden 2005-08-04 08:56:47.315617114 -0700
+++ binutils/ld/scripttempl/elf.sc 2005-08-04 11:37:29.415574217 -0700
@@ -384,21 +384,21 @@ cat <<EOF
.preinit_array ${RELOCATING-0} :
{
- ${RELOCATING+${CREATE_SHLIB-PROVIDE (__preinit_array_start = .);}}
+ ${RELOCATING+${CREATE_SHLIB-PROVIDE_HIDDEN (__preinit_array_start = .);}}
KEEP (*(.preinit_array))
- ${RELOCATING+${CREATE_SHLIB-PROVIDE (__preinit_array_end = .);}}
+ ${RELOCATING+${CREATE_SHLIB-PROVIDE_HIDDEN (__preinit_array_end = .);}}
}
.init_array ${RELOCATING-0} :
{
- ${RELOCATING+${CREATE_SHLIB-PROVIDE (__init_array_start = .);}}
+ ${RELOCATING+${CREATE_SHLIB-PROVIDE_HIDDEN (__init_array_start = .);}}
KEEP (*(.init_array))
- ${RELOCATING+${CREATE_SHLIB-PROVIDE (__init_array_end = .);}}
+ ${RELOCATING+${CREATE_SHLIB-PROVIDE_HIDDEN (__init_array_end = .);}}
}
.fini_array ${RELOCATING-0} :
{
- ${RELOCATING+${CREATE_SHLIB-PROVIDE (__fini_array_start = .);}}
+ ${RELOCATING+${CREATE_SHLIB-PROVIDE_HIDDEN (__fini_array_start = .);}}
KEEP (*(.fini_array))
- ${RELOCATING+${CREATE_SHLIB-PROVIDE (__fini_array_end = .);}}
+ ${RELOCATING+${CREATE_SHLIB-PROVIDE_HIDDEN (__fini_array_end = .);}}
}
${SMALL_DATA_CTOR-${RELOCATING+${CTOR}}}
${SMALL_DATA_DTOR-${RELOCATING+${DTOR}}}
--- binutils/ld/ld.texinfo.hide 2005-08-04 11:40:55.181708913 -0700
+++ binutils/ld/ld.texinfo 2005-08-04 11:48:25.844839998 -0700
@@ -2781,6 +2781,7 @@ the symbol and place it into the symbol
@menu
* Simple Assignments:: Simple Assignments
* PROVIDE:: PROVIDE
+* PROVIDE_HIDDEN:: PROVIDE_HIDDEN
* Source Code Reference:: How to use a linker script defined symbol in source code
@end menu
@@ -2874,6 +2875,12 @@ underscore), the linker will silently us
If the program references @samp{etext} but does not define it, the
linker will use the definition in the linker script.
+@node PROVIDE_HIDDEN
+@subsection PROVIDE_HIDDEN
+@cindex PROVIDE_HIDDEN
+Similar to @code{PROVIDE}. But the symbol will be hidden and won't be
+exported.
+
@node Source Code Reference
@subsection Source Code Reference
More information about the Binutils
mailing list