Add ELFv2 .localentry support.

This defines the ELF symbol st_other field used to encode the number
of instructions between a function "global entry" and its "local entry",
and adds support related to the local entry offset.

include/elf/
	* ppc64.h (STO_PPC64_LOCAL_BIT, STO_PPC64_LOCAL_MASK): Define.
	(ppc64_decode_local_entry, ppc64_encode_local_entry): New functions.
	(PPC64_LOCAL_ENTRY_OFFSET, PPC64_SET_LOCAL_ENTRY_OFFSET): Define.
bfd/
	* elf64-ppc.c (struct ppc_stub_hash_entry): Add "other".
	(stub_hash_newfunc): Init new ppc_stub_hash_entry field, and one
	we forgot, "plt_ent".
	(ppc64_elf_add_symbol_hook): Check ELFv1 objects don't have
	st_other bits only valid in ELFv2.
	(ppc64_elf_merge_symbol_attribute): New function.
	(ppc_type_of_stub): Add local_off param to test branch range.
	(ppc_build_one_stub): Adjust destinations for ELFv2 locals.
	(ppc_size_one_stub, toc_adjusting_stub_needed): Similarly.
	(ppc64_elf_size_stubs): Pass local_off to ppc_type_of_stub.
	Set "other" field.
	(ppc64_elf_relocate_section): Adjust destination for ELFv2 local
	calls.
gas/
	* config/tc-ppc.c (md_pseudo_table): Add .localentry.
	(ppc_elf_localentry): New function.
	(ppc_force_relocation): Force relocs on all branches to localenty
	symbols.
	(ppc_fix_adjustable): Don't reduce such symbols to section+offset.
binutils/
	* readelf.c (get_ppc64_symbol_other): New function.
	(get_symbol_other): Use it for EM_PPC64.

2 files changed, 53 insertions, 0 deletions

diff --git a/include/elf/ChangeLog b/include/elf/ChangeLog
index 2999bc8..7e98ddb 100644
--- a/include/elf/ChangeLog
+++ b/include/elf/ChangeLog
@@ -1,5 +1,11 @@
 2013-10-30  Alan Modra  <amodra@gmail.com>
 
+	* ppc64.h (STO_PPC64_LOCAL_BIT, STO_PPC64_LOCAL_MASK): Define.
+	(ppc64_decode_local_entry, ppc64_encode_local_entry): New functions.
+	(PPC64_LOCAL_ENTRY_OFFSET, PPC64_SET_LOCAL_ENTRY_OFFSET): Define.
+
+2013-10-30  Alan Modra  <amodra@gmail.com>
+
 	* ppc64.h (EF_PPC64_ABI): Define.
 
 2013-10-30  Alan Modra  <amodra@gmail.com>
diff --git a/include/elf/ppc64.h b/include/elf/ppc64.h
index 1121649..d3cfdfb 100644
--- a/include/elf/ppc64.h
+++ b/include/elf/ppc64.h
@@ -180,6 +180,53 @@ END_RELOC_NUMBERS (R_PPC64_max)
    0 for unspecified or not using any features affected by the differences.  */
 #define EF_PPC64_ABI	3
 
+/* The ELFv2 ABI uses three bits in the symbol st_other field of a
+   function definition to specify the number of instructions between a
+   function's global entry point and local entry point.
+   The global entry point is used when it is necessary to set up the
+   toc pointer (r2) for the function.  Callers must enter the global
+   entry point with r12 set to the global entry point address.  On
+   return from the function, r2 may have a different value to that
+   which it had on entry.
+   The local entry point is used when r2 is known to already be valid
+   for the function.  There is no requirement on r12 when using the
+   local entry point, and on return r2 will contain the same value as
+   at entry.
+   A value of zero in these bits means that the function has a single
+   entry point with no requirement on r12 or r2, and that on return r2
+   will contain the same value as at entry.
+   Values of one and seven are reserved.  */
+#define STO_PPC64_LOCAL_BIT		5
+#define STO_PPC64_LOCAL_MASK		(7 << STO_PPC64_LOCAL_BIT)
+
+// 3 bit other field to bytes.
+static inline unsigned int
+ppc64_decode_local_entry(unsigned int other)
+{
+  return ((1 << other) >> 2) << 2;
+}
+
+// bytes to field value.
+static inline unsigned int
+ppc64_encode_local_entry(unsigned int val)
+{
+  return (val >= 4 * 4
+	  ? (val >= 8 * 4
+	     ? (val >= 16 * 4 ? 6 : 5)
+	     : 4)
+	  : (val >= 2 * 4
+	     ? 3
+	     : (val >= 1 * 4 ? 2 : 0)));
+}
+
+/* st_other to number of bytes.  */
+#define PPC64_LOCAL_ENTRY_OFFSET(other)				\
+  ppc64_decode_local_entry (((other) & STO_PPC64_LOCAL_MASK)	\
+			    >> STO_PPC64_LOCAL_BIT)
+/* number of bytes to st_other.  */
+#define PPC64_SET_LOCAL_ENTRY_OFFSET(val)		\
+  ppc64_encode_local_entry (val) << STO_PPC64_LOCAL_BIT
+
 /* Specify the start of the .glink section.  */
 #define DT_PPC64_GLINK		DT_LOPROC