[AArch64] Relax TLS local dynamic traditional into local executable

The linker relaxation logic will be:

Code sequence I (tiny):

    0x00 adr  x0, :tlsldm:x
    0x04 bl   __tls_get_addr
         |
         V
    0x00 mrs  x0, tpidr_el0
    0x04 add  x0, x0, TCB_SIZE

Code sequence II (small):

    0x00 adrp a0, :tlsldm:x
    0x04 add  a0, #:tlsldm_lo12:x
    0x08 bl   __tls_get_addr
         |
         V
    0x00 mrs  x0, tpidr_el0
    0x04 add  x0, x0, TCB_SIZE
    0x08 nop

2015-09-09  Jiong Wang  <jiong.wang@arm.com>

bfd/
  * elfnn-aarch64.c (aarch64_tls_transition_without_check): Support
  three TLS local dynamic traditional relocations types.
  (elfNN_aarch64_tls_relax): Support TLS local dynamic traditional to
  local executable relaxation.

ld/testsuite/
  * ld-aarch64/tls-relax-ld-le-tiny.s: New testcase.
  * ld-aarch64/tls-relax-ld-le-small.s: Likewise.
  * ld-aarch64/tls-relax-ld-le-tiny.d: New expectation file.
  * ld-aarch64/tls-relax-ld-le-small.d: Likewise.
  * ld-aarch64/aarch64-elf.exp: Run new testcases.

1 files changed, 53 insertions, 0 deletions

diff --git a/bfd/elfnn-aarch64.c b/bfd/elfnn-aarch64.c
index 3c43924..696fdcc 100644
--- a/bfd/elfnn-aarch64.c
+++ b/bfd/elfnn-aarch64.c
@@ -213,6 +213,9 @@
    || (R_TYPE) == BFD_RELOC_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21	\
    || (R_TYPE) == BFD_RELOC_AARCH64_TLSIE_LD_GOTTPREL_PREL19	\
    || (R_TYPE) == BFD_RELOC_AARCH64_TLSIE_LDNN_GOTTPREL_LO12_NC	\
+   || (R_TYPE) == BFD_RELOC_AARCH64_TLSLD_ADD_LO12_NC		\
+   || (R_TYPE) == BFD_RELOC_AARCH64_TLSLD_ADR_PAGE21		\
+   || (R_TYPE) == BFD_RELOC_AARCH64_TLSLD_ADR_PREL21		\
    || (R_TYPE) == BFD_RELOC_AARCH64_TLSDESC_ADR_PAGE21		\
    || (R_TYPE) == BFD_RELOC_AARCH64_TLSDESC_ADR_PREL21		\
    || (R_TYPE) == BFD_RELOC_AARCH64_TLSDESC_LD_PREL19		\
@@ -4390,6 +4393,11 @@ aarch64_tls_transition_without_check (bfd_reloc_code_real_type r_type,
       /* Instructions with these relocations will become NOPs.  */
       return BFD_RELOC_AARCH64_NONE;
 
+    case BFD_RELOC_AARCH64_TLSLD_ADD_LO12_NC:
+    case BFD_RELOC_AARCH64_TLSLD_ADR_PAGE21:
+    case BFD_RELOC_AARCH64_TLSLD_ADR_PREL21:
+      return is_local ? BFD_RELOC_AARCH64_NONE : r_type;
+
     default:
       break;
     }
@@ -5616,6 +5624,51 @@ elfNN_aarch64_tls_relax (struct elf_aarch64_link_hash_table *globals,
 	}
       return bfd_reloc_continue;
 
+    case BFD_RELOC_AARCH64_TLSLD_ADR_PREL21:
+      /* LD->LE relaxation (tiny):
+	 adr  x0, :tlsldm:x  => mrs x0, tpidr_el0
+	 bl   __tls_get_addr => add x0, x0, TCB_SIZE
+       */
+      if (is_local)
+	{
+	  BFD_ASSERT (rel->r_offset + 4 == rel[1].r_offset);
+	  BFD_ASSERT (ELFNN_R_TYPE (rel[1].r_info) == AARCH64_R (CALL26));
+	  /* No need of CALL26 relocation for tls_get_addr.  */
+	  rel[1].r_info = ELFNN_R_INFO (STN_UNDEF, R_AARCH64_NONE);
+	  bfd_putl32 (0xd53bd040, contents + rel->r_offset + 0);
+	  bfd_putl32 (0x91004000, contents + rel->r_offset + 4);
+	  return bfd_reloc_ok;
+	}
+      return bfd_reloc_continue;
+
+    case BFD_RELOC_AARCH64_TLSLD_ADR_PAGE21:
+      /* LD->LE relaxation (small):
+	 adrp  x0, :tlsldm:x       => mrs x0, tpidr_el0
+       */
+      if (is_local)
+	{
+	  bfd_putl32 (0xd53bd040, contents + rel->r_offset);
+	  return bfd_reloc_ok;
+	}
+      return bfd_reloc_continue;
+
+    case BFD_RELOC_AARCH64_TLSLD_ADD_LO12_NC:
+      /* LD->LE relaxation (small):
+	 add   x0, #:tlsldm_lo12:x => add x0, x0, TCB_SIZE
+	 bl   __tls_get_addr       => nop
+       */
+      if (is_local)
+	{
+	  BFD_ASSERT (rel->r_offset + 4 == rel[1].r_offset);
+	  BFD_ASSERT (ELFNN_R_TYPE (rel[1].r_info) == AARCH64_R (CALL26));
+	  /* No need of CALL26 relocation for tls_get_addr.  */
+	  rel[1].r_info = ELFNN_R_INFO (STN_UNDEF, R_AARCH64_NONE);
+	  bfd_putl32 (0x91004000, contents + rel->r_offset + 0);
+	  bfd_putl32 (0xd503201f, contents + rel->r_offset + 4);
+	  return bfd_reloc_ok;
+	}
+      return bfd_reloc_continue;
+
     default:
       return bfd_reloc_continue;
     }