From 397998fc32a34d3c8993ef46da45c3957a4dd402 Mon Sep 17 00:00:00 2001
From: Alan Modra <amodra@gmail.com>
Date: Tue, 3 Jun 2014 10:55:29 +0930
Subject: Support fusion for ELFv2 stubs

Power8 fuses addis,addi and addis,ld sequences when the target of the
addis is the same as the addi/ld.  Thus
    addis r12,r2,xxx@ha
    addi r12,r12,xxx@l / ld r12,xxx@l(r12)
is faster than
    addis r11,r2,xxx@ha
    addi r12,r11,xxx@l / ld r12,xxx@l(r11)
So use the form that allows fusion in plt call and branch stubs.

bfd/
	* elf64-ppc.c (ADDIS_R12_R2): Define.
	(build_plt_stub): Support fusion on ELFv2 stub.
	(ppc_build_one_stub): Likewise for plt branch stubs.
gold/
	* powerpc.cc (addis_12_2): Define.
	(Stub_table::do_write): Support fusion on ELFv2 stubs.
ld/testsuite/
	* ld-powerpc/elfv2exe.d: Update for changed plt call stubs.
gdb/
	* ppc64-tdep.c (ppc64_standard_linkage8): New.
	(ppc64_skip_trampoline_code): Recognise ELFv2 stub supporting fusion.
---
 gold/powerpc.cc | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

(limited to 'gold/powerpc.cc')

diff --git a/gold/powerpc.cc b/gold/powerpc.cc
index 1078017..bd3994a 100644
--- a/gold/powerpc.cc
+++ b/gold/powerpc.cc
@@ -3077,6 +3077,7 @@ static const uint32_t addis_3_13	= 0x3c6d0000;
 static const uint32_t addis_11_2	= 0x3d620000;
 static const uint32_t addis_11_11	= 0x3d6b0000;
 static const uint32_t addis_11_30	= 0x3d7e0000;
+static const uint32_t addis_12_2	= 0x3d820000;
 static const uint32_t addis_12_12	= 0x3d8c0000;
 static const uint32_t b			= 0x48000000;
 static const uint32_t bcl_20_31		= 0x429f0005;
@@ -4210,10 +4211,20 @@ Stub_table<size, big_endian>::do_write(Output_file* of)
 		{
 		  write_insn<big_endian>(p, std_2_1 + this->targ_->stk_toc());
 		  p += 4;
-		  write_insn<big_endian>(p, addis_11_2 + ha(off));
-		  p += 4;
-		  write_insn<big_endian>(p, ld_12_11 + l(off));
-		  p += 4;
+		  if (plt_load_toc)
+		    {
+		      write_insn<big_endian>(p, addis_11_2 + ha(off));
+		      p += 4;
+		      write_insn<big_endian>(p, ld_12_11 + l(off));
+		      p += 4;
+		    }
+		  else
+		    {
+		      write_insn<big_endian>(p, addis_12_2 + ha(off));
+		      p += 4;
+		      write_insn<big_endian>(p, ld_12_12 + l(off));
+		      p += 4;
+		    }
 		  if (plt_load_toc
 		      && ha(off + 8 + 8 * static_chain) != ha(off))
 		    {
@@ -4312,8 +4323,8 @@ Stub_table<size, big_endian>::do_write(Output_file* of)
 		}
 	      else
 		{
-		  write_insn<big_endian>(p, addis_11_2 + ha(brltoff)),	p += 4;
-		  write_insn<big_endian>(p, ld_12_11 + l(brltoff)),	p += 4;
+		  write_insn<big_endian>(p, addis_12_2 + ha(brltoff)),	p += 4;
+		  write_insn<big_endian>(p, ld_12_12 + l(brltoff)),	p += 4;
 		}
 	      write_insn<big_endian>(p, mtctr_12),			p += 4;
 	      write_insn<big_endian>(p, bctr);
-- 
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