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Support object attributes numbers below 4
- From: "Joseph S. Myers" <joseph at codesourcery dot com>
- To: binutils at sourceware dot org
- Date: Tue, 15 Jun 2010 16:33:36 +0000 (UTC)
- Subject: Support object attributes numbers below 4
The object attributes support in BFD currently assumes that no object
attribute has a number smaller than 4. This is indeed true for ARM
EABI attributes - the numbers within subsections were probably
deliberately chosen not to overlap with those indicating whether a
subsection applies to a whole file, a section or a symbol - and for
GNU attributes. However, I am now implementing TI C6X attributes, and
those use number 2 for Tag_C6XABI_Tag_CPU_arch (there is no actual
ambiguity between attributes within subsections and those at the start
of a subsection).
This patch allows the possibility of attributes numbered below 4,
removing the hardcoded 4s that were commented on in
<http://sourceware.org/ml/binutils/2007-07/msg00398.html> and
replacing them with LEAST_KNOWN_OBJ_ATTRIBUTE. In this patch that
macro remains defined as 4; the C6X attributes patch will change it to
2. If any target requires a value of 0, some further changes will be
needed because of code such as:
/* Use the Tag_null value to indicate the attributes have been
initialized. */
out_attr[0].i = 1;
Tested with no regressions with cross to arm-eabi; I also tested the
variant with value 2 for LEAST_KNOWN_OBJ_ATTRIBUTE to make sure that
didn't break ARM. OK to commit?
2010-06-15 Joseph Myers <joseph@codesourcery.com>
* elf-bfd.h (LEAST_KNOWN_OBJ_ATTRIBUTE): Define.
(struct elf_backend_data): Update comment on obj_attrs_order.
* elf-attrs.c (vendor_obj_attr_size, vendor_set_obj_attr_contents,
_bfd_elf_copy_obj_attributes): Use LEAST_KNOWN_OBJ_ATTRIBUTE
instead of hardcoded 4.
* elf32-arm.c (elf32_arm_obj_attrs_order): Use
LEAST_KNOWN_OBJ_ATTRIBUTE and LEAST_KNOWN_OBJ_ATTRIBUTE + 1
instead of hardcoded 4 and 5.
(elf32_arm_merge_eabi_attributes): Use LEAST_KNOWN_OBJ_ATTRIBUTE
instead of hardcoded 4.
Index: elf-attrs.c
===================================================================
RCS file: /cvs/src/src/bfd/elf-attrs.c,v
retrieving revision 1.11
diff -u -p -r1.11 elf-attrs.c
--- elf-attrs.c 28 Dec 2009 18:37:30 -0000 1.11
+++ elf-attrs.c 15 Jun 2010 16:20:23 -0000
@@ -1,5 +1,5 @@
/* ELF attributes support (based on ARM EABI attributes).
- Copyright 2005, 2006, 2007, 2009
+ Copyright 2005, 2006, 2007, 2009, 2010
Free Software Foundation, Inc.
This file is part of BFD, the Binary File Descriptor library.
@@ -96,7 +96,7 @@ vendor_obj_attr_size (bfd *abfd, int ven
attr = elf_known_obj_attributes (abfd)[vendor];
size = 0;
- for (i = 4; i < NUM_KNOWN_OBJ_ATTRIBUTES; i++)
+ for (i = LEAST_KNOWN_OBJ_ATTRIBUTE; i < NUM_KNOWN_OBJ_ATTRIBUTES; i++)
size += obj_attr_size (i, &attr[i]);
for (list = elf_other_obj_attributes (abfd)[vendor];
@@ -188,7 +188,7 @@ vendor_set_obj_attr_contents (bfd *abfd,
p += 4;
attr = elf_known_obj_attributes (abfd)[vendor];
- for (i = 4; i < NUM_KNOWN_OBJ_ATTRIBUTES; i++)
+ for (i = LEAST_KNOWN_OBJ_ATTRIBUTE; i < NUM_KNOWN_OBJ_ATTRIBUTES; i++)
{
int tag = i;
if (get_elf_backend_data (abfd)->obj_attrs_order)
@@ -349,9 +349,11 @@ _bfd_elf_copy_obj_attributes (bfd *ibfd,
for (vendor = OBJ_ATTR_FIRST; vendor <= OBJ_ATTR_LAST; vendor++)
{
- in_attr = &elf_known_obj_attributes (ibfd)[vendor][4];
- out_attr = &elf_known_obj_attributes (obfd)[vendor][4];
- for (i = 4; i < NUM_KNOWN_OBJ_ATTRIBUTES; i++)
+ in_attr
+ = &elf_known_obj_attributes (ibfd)[vendor][LEAST_KNOWN_OBJ_ATTRIBUTE];
+ out_attr
+ = &elf_known_obj_attributes (obfd)[vendor][LEAST_KNOWN_OBJ_ATTRIBUTE];
+ for (i = LEAST_KNOWN_OBJ_ATTRIBUTE; i < NUM_KNOWN_OBJ_ATTRIBUTES; i++)
{
out_attr->type = in_attr->type;
out_attr->i = in_attr->i;
Index: elf-bfd.h
===================================================================
RCS file: /cvs/src/src/bfd/elf-bfd.h,v
retrieving revision 1.304
diff -u -p -r1.304 elf-bfd.h
--- elf-bfd.h 30 Apr 2010 18:27:29 -0000 1.304
+++ elf-bfd.h 15 Jun 2010 16:20:24 -0000
@@ -1245,10 +1245,11 @@ struct elf_backend_data
/* The section type to use for an attributes section. */
unsigned int obj_attrs_section_type;
- /* This function determines the order in which any attributes are written.
- It must be defined for input in the range 4..NUM_KNOWN_OBJ_ATTRIBUTES-1
- (this range is used in order to make unity easy). The returned value is
- the actual tag number to place in the input position. */
+ /* This function determines the order in which any attributes are
+ written. It must be defined for input in the range
+ LEAST_KNOWN_OBJ_ATTRIBUTE..NUM_KNOWN_OBJ_ATTRIBUTES-1 (this range
+ is used in order to make unity easy). The returned value is the
+ actual tag number to place in the input position. */
int (*obj_attrs_order) (int);
/* This is TRUE if the linker should act like collect and gather
@@ -1412,6 +1413,12 @@ struct bfd_elf_section_data
#define get_elf_backend_data(abfd) \
xvec_get_elf_backend_data ((abfd)->xvec)
+/* The least object attributes (within an attributes subsection) known
+ for any target. Some code assumes that the value 0 is not used and
+ the field for that attribute can instead be used as a marker to
+ indicate that attributes have been initialized. */
+#define LEAST_KNOWN_OBJ_ATTRIBUTE 4
+
/* The maximum number of known object attributes for any target. */
#define NUM_KNOWN_OBJ_ATTRIBUTES 71
Index: elf32-arm.c
===================================================================
RCS file: /cvs/src/src/bfd/elf32-arm.c,v
retrieving revision 1.235
diff -u -p -r1.235 elf32-arm.c
--- elf32-arm.c 11 May 2010 17:36:27 -0000 1.235
+++ elf32-arm.c 15 Jun 2010 16:20:25 -0000
@@ -9624,9 +9624,9 @@ elf32_arm_obj_attrs_arg_type (int tag)
static int
elf32_arm_obj_attrs_order (int num)
{
- if (num == 4)
+ if (num == LEAST_KNOWN_OBJ_ATTRIBUTE)
return Tag_conformance;
- if (num == 5)
+ if (num == LEAST_KNOWN_OBJ_ATTRIBUTE + 1)
return Tag_nodefaults;
if ((num - 2) < Tag_nodefaults)
return num - 2;
@@ -9932,7 +9932,7 @@ elf32_arm_merge_eabi_attributes (bfd *ib
}
}
- for (i = 4; i < NUM_KNOWN_OBJ_ATTRIBUTES; i++)
+ for (i = LEAST_KNOWN_OBJ_ATTRIBUTE; i < NUM_KNOWN_OBJ_ATTRIBUTES; i++)
{
/* Merge this attribute with existing attributes. */
switch (i)
--
Joseph S. Myers
joseph@codesourcery.com