PowerPC addpcis fix

This came up because I was looking at ld/tmpdir/addpcis.o and noticed
the odd addends on REL16DX_HA.  They ought to both be -4.  The error
crept in due REL16DX_HA howto being pc-relative (as indeed it should
be), and code at gas/write.c:1001 after this comment
	      /* Make it pc-relative.  If the back-end code has not
		 selected a pc-relative reloc, cancel the adjustment
		 we do later on all pc-relative relocs.  */
*not* cancelling the pc-relative adjustment.  So I've made a dummy
non-relative split reloc so that the generic code handles this, rather
than attempting to add hacks later in md_apply_fix which would not be
very robust.  Having the new internal reloc also makes it easy to
support

 addpcis rx,sym@ha

as an equivalent to

 addpcis rx,(sym-0f)@ha
0:

The patch also fixes overflow checking, which must test whether the
addi will overflow too since @l relocs don't have any overflow check.

Lastly, since I was poking at md_apply_fix, I arranged to have the
generic gas/write.c code emit errors for subtraction expressions where
we lack reloc support.

include/
	* elf/ppc64.h (R_PPC64_16DX_HA): New.  Expand fake reloc comment.
	* elf/ppc.h (R_PPC_16DX_HA): Likewise.
bfd/
	* reloc.c (BFD_RELOC_PPC_16DX_HA): New.
	* elf64-ppc.c (ppc64_elf_howto_raw <R_PPC64_16DX_HA>): New howto.
	(ppc64_elf_reloc_type_lookup): Translate new bfd reloc.
	(ppc64_elf_ha_reloc): Correct overflow test on REL16DX_HA.
	(ppc64_elf_relocate_section): Likewise.
	* elf32-ppc.c (ppc_elf_howto_raw <R_PPC_16DX_HA>): New howto.
	(ppc_elf_reloc_type_lookup): Translate new bfd reloc.
	(ppc_elf_check_relocs): Handle R_PPC_16DX_HA to pacify gcc.
	* libbfd.h: Regenerate.
	* bfd-in2.h: Regenerate.
gas/
	* config/tc-ppc.c (md_assemble): Use BFD_RELOC_PPC_16DX_HA for addpcis.
	(md_apply_fix): Remove fx_subsy check.  Move code converting to
	pcrel reloc earlier and handle BFD_RELOC_PPC_16DX_HA.  Remove code
	emiiting errors on seeing fx_pcrel set on unexpected relocs, as
	that is done now by the generic code via..
	* config/tc-ppc.h (TC_FORCE_RELOCATION_SUB_LOCAL): ..this. Define.
	(TC_VALIDATE_FIX_SUB): Define.
ld/
	* testsuite/ld-powerpc/addpcis.d: Define ext1 and ext2 at
	limits of addpcis range.

1 files changed, 17 insertions, 0 deletions

diff --git a/bfd/elf32-ppc.c b/bfd/elf32-ppc.c
index 834ef67..d98b776 100644
--- a/bfd/elf32-ppc.c
+++ b/bfd/elf32-ppc.c
@@ -1746,6 +1746,21 @@ static reloc_howto_type ppc_elf_howto_raw[] = {
 	 0x1fffc1,		/* dst_mask */
 	 TRUE),			/* pcrel_offset */
 
+  /* A split-field reloc for addpcis, non-relative (gas internal use only).  */
+  HOWTO (R_PPC_16DX_HA,		/* type */
+	 16,			/* rightshift */
+	 2,			/* size (0 = byte, 1 = short, 2 = long) */
+	 16,			/* bitsize */
+	 FALSE,			/* pc_relative */
+	 0,			/* bitpos */
+	 complain_overflow_signed, /* complain_on_overflow */
+	 ppc_elf_addr16_ha_reloc, /* special_function */
+	 "R_PPC_16DX_HA",	/* name */
+	 FALSE,			/* partial_inplace */
+	 0,			/* src_mask */
+	 0x1fffc1,		/* dst_mask */
+	 FALSE),		/* pcrel_offset */
+
   /* GNU extension to record C++ vtable hierarchy.  */
   HOWTO (R_PPC_GNU_VTINHERIT,	/* type */
 	 0,			/* rightshift */
@@ -2002,6 +2017,7 @@ ppc_elf_reloc_type_lookup (bfd *abfd ATTRIBUTE_UNUSED,
     case BFD_RELOC_LO16_PCREL:		r = R_PPC_REL16_LO;		break;
     case BFD_RELOC_HI16_PCREL:		r = R_PPC_REL16_HI;		break;
     case BFD_RELOC_HI16_S_PCREL:	r = R_PPC_REL16_HA;		break;
+    case BFD_RELOC_PPC_16DX_HA:		r = R_PPC_16DX_HA;		break;
     case BFD_RELOC_PPC_REL16DX_HA:	r = R_PPC_REL16DX_HA;		break;
     case BFD_RELOC_VTABLE_INHERIT:	r = R_PPC_GNU_VTINHERIT;	break;
     case BFD_RELOC_VTABLE_ENTRY:	r = R_PPC_GNU_VTENTRY;		break;
@@ -4351,6 +4367,7 @@ ppc_elf_check_relocs (bfd *abfd,
 	case R_PPC_RELAX:
 	case R_PPC_RELAX_PLT:
 	case R_PPC_RELAX_PLTREL24:
+	case R_PPC_16DX_HA:
 	  break;
 
 	  /* These should only appear in dynamic objects.  */