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.

8 files changed, 85 insertions, 18 deletions

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 8c93f39..396b7ab 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2014-06-03  Alan Modra  <amodra@gmail.com>
+
+	* elf64-ppc.c (ADDIS_R12_R2): Define.
+	(build_plt_stub): Support fusion on ELFv2 stub.
+	(ppc_build_one_stub): Likewise for plt branch stubs.
+
 2014-05-28  Alan Modra  <amodra@gmail.com>
 
 	* elf32-rx.c (rx_table_map): Delete set but not used variables.
diff --git a/bfd/elf64-ppc.c b/bfd/elf64-ppc.c
index fdca0c6..e7e2e39 100644
--- a/bfd/elf64-ppc.c
+++ b/bfd/elf64-ppc.c
@@ -173,6 +173,7 @@ static bfd_vma opd_entry_value
 
 #define LD_R2_0R1	0xe8410000	/* ld    %r2,0(%r1)      */
 
+#define ADDIS_R12_R2	0x3d820000	/* addis %r12,%r2,xxx@ha     */
 #define ADDIS_R12_R12	0x3d8c0000	/* addis %r12,%r12,xxx@ha */
 #define LD_R12_0R12	0xe98c0000	/* ld    %r12,xxx@l(%r12) */
 
@@ -10246,8 +10247,16 @@ build_plt_stub (struct ppc_link_hash_table *htab,
       if (ALWAYS_EMIT_R2SAVE
 	  || stub_entry->stub_type == ppc_stub_plt_call_r2save)
 	bfd_put_32 (obfd, STD_R2_0R1 + STK_TOC (htab), p),	p += 4;
-      bfd_put_32 (obfd, ADDIS_R11_R2 | PPC_HA (offset), p),	p += 4;
-      bfd_put_32 (obfd, LD_R12_0R11 | PPC_LO (offset), p),	p += 4;
+      if (plt_load_toc)
+	{
+	  bfd_put_32 (obfd, ADDIS_R11_R2 | PPC_HA (offset), p),	p += 4;
+	  bfd_put_32 (obfd, LD_R12_0R11 | PPC_LO (offset), p),	p += 4;
+	}
+      else
+	{
+	  bfd_put_32 (obfd, ADDIS_R12_R2 | PPC_HA (offset), p),	p += 4;
+	  bfd_put_32 (obfd, LD_R12_0R12 | PPC_LO (offset), p),	p += 4;
+	}
       if (plt_load_toc
 	  && PPC_HA (offset + 8 + 8 * plt_static_chain) != PPC_HA (offset))
 	{
@@ -10668,10 +10677,10 @@ ppc_build_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
 	    {
 	      size = 16;
 	      bfd_put_32 (htab->params->stub_bfd,
-			  ADDIS_R11_R2 | PPC_HA (off), loc);
+			  ADDIS_R12_R2 | PPC_HA (off), loc);
 	      loc += 4;
 	      bfd_put_32 (htab->params->stub_bfd,
-			  LD_R12_0R11 | PPC_LO (off), loc);
+			  LD_R12_0R12 | PPC_LO (off), loc);
 	    }
 	  else
 	    {
@@ -10697,10 +10706,10 @@ ppc_build_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
 	    {
 	      size += 4;
 	      bfd_put_32 (htab->params->stub_bfd,
-			  ADDIS_R11_R2 | PPC_HA (off), loc);
+			  ADDIS_R12_R2 | PPC_HA (off), loc);
 	      loc += 4;
 	      bfd_put_32 (htab->params->stub_bfd,
-			  LD_R12_0R11 | PPC_LO (off), loc);
+			  LD_R12_0R12 | PPC_LO (off), loc);
 	    }
 	  else
 	    bfd_put_32 (htab->params->stub_bfd, LD_R12_0R2 | PPC_LO (off), loc);
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 5e428f5..d7f5c6f 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2014-06-03  Alan Modra  <amodra@gmail.com>
+
+	* ppc64-tdep.c (ppc64_standard_linkage8): New.
+	(ppc64_skip_trampoline_code): Recognise ELFv2 stub supporting fusion.
+
 2014-06-02  Doug Evans  <dje@google.com>
 
 	Add support for skeletonless type units.
diff --git a/gdb/ppc64-tdep.c b/gdb/ppc64-tdep.c
index cbbbedc..8acd754 100644
--- a/gdb/ppc64-tdep.c
+++ b/gdb/ppc64-tdep.c
@@ -303,6 +303,29 @@ static struct ppc_insn_pattern ppc64_standard_linkage7[] =
     { 0, 0, 0 }
   };
 
+/* ELFv2 PLT call stub to access PLT entries more than +/- 32k from r2,
+   supporting fusion.  */
+
+static struct ppc_insn_pattern ppc64_standard_linkage8[] =
+  {
+    /* std r2, 24(r1) <optional> */
+    { -1, insn_ds (62, 2, 1, 24, 0), 1 },
+
+    /* addis r12, r2, <any> */
+    { insn_d (-1, -1, -1, 0), insn_d (15, 12, 2, 0), 0 },
+
+    /* ld r12, <any>(r12) */
+    { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 12, 12, 0, 0), 0 },
+
+    /* mtctr r12 */
+    { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 12, 9, 467), 0 },
+
+    /* bctr */
+    { -1, 0x4e800420, 0 },
+
+    { 0, 0, 0 }
+  };
+
 /* When the dynamic linker is doing lazy symbol resolution, the first
    call to a function in another object will go like this:
 
@@ -437,10 +460,14 @@ ppc64_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
 				    ARRAY_SIZE (ppc64_standard_linkage4))),
 			  MAX (MAX (ARRAY_SIZE (ppc64_standard_linkage5),
 				    ARRAY_SIZE (ppc64_standard_linkage6)),
-			       ARRAY_SIZE (ppc64_standard_linkage7))) - 1];
+			       MAX (ARRAY_SIZE (ppc64_standard_linkage7),
+				    ARRAY_SIZE (ppc64_standard_linkage8))))
+		     - 1];
   CORE_ADDR target;
 
-  if (ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage7, insns))
+  if (ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage8, insns))
+    pc = ppc64_standard_linkage4_target (frame, pc, insns);
+  else if (ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage7, insns))
     pc = ppc64_standard_linkage3_target (frame, pc, insns);
   else if (ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage6, insns))
     pc = ppc64_standard_linkage4_target (frame, pc, insns);
diff --git a/gold/ChangeLog b/gold/ChangeLog
index 0bde6a1..5e15f5e 100644
--- a/gold/ChangeLog
+++ b/gold/ChangeLog
@@ -1,5 +1,10 @@
 2014-06-03  Alan Modra  <amodra@gmail.com>
 
+	* powerpc.cc (addis_12_2): Define.
+	(Stub_table::do_write): Support fusion on ELFv2 stubs.
+
+2014-06-03  Alan Modra  <amodra@gmail.com>
+
 	* testsuite/plugin_test.c (parse_readelf_line): Skip non-visibility
 	st_other output.
 
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);
diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog
index bd604b6..bc80518 100644
--- a/ld/testsuite/ChangeLog
+++ b/ld/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2014-06-03  Alan Modra  <amodra@gmail.com>
+
+	* ld-powerpc/elfv2exe.d: Update for changed plt call stubs.
+
 2014-05-28  Matthew Fortune  <matthew.fortune@imgtec.com>
 
 	* lib/ld-lib.exp: Add objcopy_objects command to run_dump_test.
diff --git a/ld/testsuite/ld-powerpc/elfv2exe.d b/ld/testsuite/ld-powerpc/elfv2exe.d
index 7ff9d38..9ea816c 100644
--- a/ld/testsuite/ld-powerpc/elfv2exe.d
+++ b/ld/testsuite/ld-powerpc/elfv2exe.d
@@ -8,14 +8,14 @@
 Disassembly of section \.text:
 
 0+100000c0 <.*\.plt_branch\.f2>:
-.*:	(ff ff 62 3d|3d 62 ff ff) 	addis   r11,r2,-1
-.*:	(f0 7f 8b e9|e9 8b 7f f0) 	ld      r12,32752\(r11\)
+.*:	(ff ff 82 3d|3d 82 ff ff) 	addis   r12,r2,-1
+.*:	(f0 7f 8c e9|e9 8c 7f f0) 	ld      r12,32752\(r12\)
 .*:	(a6 03 89 7d|7d 89 03 a6) 	mtctr   r12
 .*:	(20 04 80 4e|4e 80 04 20) 	bctr
 
 0+100000d0 <.*\.plt_branch\.f4>:
-.*:	(ff ff 62 3d|3d 62 ff ff) 	addis   r11,r2,-1
-.*:	(f8 7f 8b e9|e9 8b 7f f8) 	ld      r12,32760\(r11\)
+.*:	(ff ff 82 3d|3d 82 ff ff) 	addis   r12,r2,-1
+.*:	(f8 7f 8c e9|e9 8c 7f f8) 	ld      r12,32760\(r12\)
 .*:	(a6 03 89 7d|7d 89 03 a6) 	mtctr   r12
 .*:	(20 04 80 4e|4e 80 04 20) 	bctr