From 3734320dc054bd9f6632607e9e5c901c57450791 Mon Sep 17 00:00:00 2001
From: Matthew Fortune <matthew.fortune@mips.com>
Date: Mon, 13 May 2019 17:03:19 -0700
Subject: [MIPS] Add generation of PLT entries with compact jumps for MIPS R6

Add a new option to get the linker to emit PLTs that use compact
branches instead of delay slot branches.

bfd/
	* elfxx-mips.c (LA25_BC): New macro.
	(mips_elf_link_hash_table)<compact_branches>: New field.
	(STUB_JALRC): New macro.
	(mipsr6_o32_exec_plt0_entry_compact): New array.
	(mipsr6_n32_exec_plt0_entry_compact): Likewise.
	(mipsr6_n64_exec_plt0_entry_compact): Likewise.
	(mipsr6_exec_plt_entry_compact): Likewise.
	(mips_elf_create_la25_stub): Use BC instead of J for stubs
	when compact_branches is true.
	(_bfd_mips_elf_finish_dynamic_symbol): Choose the compact
	PLT for MIPSR6 with compact_branches.  Do not reorder the
	compact branches PLT.  Switch the lazy stub for MIPSR6
	with compact_branches to use JALRC.
	(mips_finish_exec_plt): Choose the compact PLT0 for MIPSR6
	when compact_branches is true.
	(_bfd_mips_elf_compact_branches): New function.
	* elfxx-mips.h (_bfd_mips_elf_compact_branches): New prototype.

ld/
	* emultempl/mipself.em (compact_branches): New static variable.
	(mips_create_output_section_statements): Call
	_bfd_mips_elf_compact_branches.
	(PARSE_AND_LIST_PROLOGUE): Add OPTION_COMPACT_BRANCHES and
	OPTION_NO_COMPACT_BRANCHES.
	(PARSE_AND_LIST_LONGOPTS): Add compact-branches,
	no-compact-branches.
	(PARSE_AND_LIST_OPTIONS): Add --compact-branches,
	--no-compact-branches.
	(PARSE_AND_LIST_ARGS_CASES): Handle the above.
	* ld.texinfo: Document --compact-branches, --no-compact-branches.
	* testsuite/ld-mips-elf/pic-and-nonpic-1-r6.dd: New test.
	* testsuite/ld-mips-elf/pic-and-nonpic-1-r6.nd: New test.
	* testsuite/ld-mips-elf/pic-and-nonpic-3a-r6.dd: New test.
	* testsuite/ld-mips-elf/pic-and-nonpic-3a-r6.gd: New test.
	* testsuite/ld-mips-elf/pic-and-nonpic-1a-r6.s: New test source.
	* testsuite/ld-mips-elf/pic-and-nonpic-3a-r6.s: New test source.
	* testsuite/ld-mips-elf/mips-elf.exp: Run the new tests.
---
 ld/emultempl/mipself.em | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

(limited to 'ld/emultempl')

diff --git a/ld/emultempl/mipself.em b/ld/emultempl/mipself.em
index d9eeef3..ec908d7 100644
--- a/ld/emultempl/mipself.em
+++ b/ld/emultempl/mipself.em
@@ -44,6 +44,7 @@ static bfd *stub_bfd;
 
 static bfd_boolean insn32;
 static bfd_boolean ignore_branch_isa;
+static bfd_boolean compact_branches;
 
 static void
 mips_after_parse (void)
@@ -216,7 +217,10 @@ mips_create_output_section_statements (void)
 				${gnu_target});
 
   if (is_mips_elf (link_info.output_bfd))
-    _bfd_mips_elf_init_stubs (&link_info, mips_add_stub_section);
+    {
+      _bfd_mips_elf_compact_branches (&link_info, compact_branches);
+      _bfd_mips_elf_init_stubs (&link_info, mips_add_stub_section);
+    }
 }
 
 /* This is called after we have merged the private data of the input bfds.  */
@@ -269,7 +273,9 @@ enum
     OPTION_INSN32 = 301,
     OPTION_NO_INSN32,
     OPTION_IGNORE_BRANCH_ISA,
-    OPTION_NO_IGNORE_BRANCH_ISA
+    OPTION_NO_IGNORE_BRANCH_ISA,
+    OPTION_COMPACT_BRANCHES,
+    OPTION_NO_COMPACT_BRANCHES
   };
 '
 
@@ -278,6 +284,8 @@ PARSE_AND_LIST_LONGOPTS='
   { "no-insn32", no_argument, NULL, OPTION_NO_INSN32 },
   { "ignore-branch-isa", no_argument, NULL, OPTION_IGNORE_BRANCH_ISA },
   { "no-ignore-branch-isa", no_argument, NULL, OPTION_NO_IGNORE_BRANCH_ISA },
+  { "compact-branches", no_argument, NULL, OPTION_COMPACT_BRANCHES },
+  { "no-compact-branches", no_argument, NULL, OPTION_NO_COMPACT_BRANCHES },
 '
 
 PARSE_AND_LIST_OPTIONS='
@@ -295,6 +303,12 @@ PARSE_AND_LIST_OPTIONS='
   --no-ignore-branch-isa      Reject invalid branch relocations requiring\n\
                               an ISA mode switch\n"
 		   ));
+  fprintf (file, _("\
+  --compact-branches          Generate compact branches/jumps for MIPS R6\n"
+		   ));
+  fprintf (file, _("\
+  --no-compact-branches       Generate delay slot branches/jumps for MIPS R6\n"
+		   ));
 '
 
 PARSE_AND_LIST_ARGS_CASES='
@@ -313,6 +327,14 @@ PARSE_AND_LIST_ARGS_CASES='
     case OPTION_NO_IGNORE_BRANCH_ISA:
       ignore_branch_isa = FALSE;
       break;
+
+    case OPTION_COMPACT_BRANCHES:
+      compact_branches = TRUE;
+      break;
+
+    case OPTION_NO_COMPACT_BRANCHES:
+      compact_branches = FALSE;
+      break;
 '
 
 LDEMUL_AFTER_PARSE=mips_after_parse
-- 
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