[PATCH] aarch64: Set pcrel_off for COFF relocations

[Mark Harmstone]

The pcrel_off flag of reloc_howto_type specifies that "the displacement part
of an instruction [is left] empty", which is the case for ELF and COFF files.
This wasn't being set in bfd/coff-aarch64.c, with the result that when using
ld with a linker script, bfd_perform_relocation was writing incorrect
relocations.

This isn't an issue when using aarch64-w64-mingw32-ld in its normal
mode to create PE files, as relocation gets done in a different way
that doesn't use bfd_generic.

Minimal reproducer:

  $ cat tmp1.s
  .long   0x12345678
  b       foo

  $ cat tmp2.s
  .global foo
  foo:
  .long   0x9abcdef0

  $ cat tmp.ld
  OUTPUT_FORMAT("binary")
  OUTPUT_ARCH("aarch64")
  TARGET("pei-aarch64-little")
  SECTIONS
  {
      .text : AT(text) {
          text = .;
          *(.text)
      }
  }

  $ aarch64-w64-mingw32-as tmp1.s -o tmp1.o
  $ aarch64-w64-mingw32-as tmp2.s -o tmp2.o
  $ ld -T tmp.ld tmp1.o tmp2.o -o tmp
  $ objdump -b binary -m aarch64 -D tmp

  tmp:     file format binary

  Disassembly of section .data:

  0000000000000000 <.data>:
    0:   12345678        and     w24, w19, #0xfffff003
    4:   14000002        b       0xc // wrong, should be "b 0x8"
    8:   9abcdef0        .inst   0x9abcdef0 ; undefined

	* bfd/coff-aarch64.c (HOW): Pass true through to HOWTO for
	pcrel_offset.
---
 bfd/coff-aarch64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/bfd/coff-aarch64.c b/bfd/coff-aarch64.c
index 48b8bfaf496..4861bf478ed 100644
--- a/bfd/coff-aarch64.c
+++ b/bfd/coff-aarch64.c
@@ -244,7 +244,7 @@ coff_aarch64_secrel_reloc (bfd *abfd,
 #define HOWTO_INSTALL_ADDEND 1
 #define HOW(type, right, size, bits, pcrel, left, ovf, func, mask) \
   HOWTO (type, right, size, bits, pcrel, left, complain_overflow_##ovf, \
-	 coff_aarch64_##func, #type, true, mask, mask, false)
+	 coff_aarch64_##func, #type, true, mask, mask, true)
 
 static const reloc_howto_type arm64_reloc_howto_abs
 = HOW (IMAGE_REL_ARM64_ABSOLUTE,
-- 
2.49.1