Add support for the C_SKY series of processors.

This patch series is a new binutils port for C-SKY processors, including support for both the V1 and V2 processor variants.  V1 is derived from the MCore architecture while V2 is substantially different, with mixed 16- and 32-bit instructions, a larger register set, a different (but overlapping) ABI, etc.  There is support for bare-metal ELF targets and Linux with both glibc and uClibc.

This code is being contributed jointly by C-SKY Microsystems and Mentor Graphics.  C-SKY is responsible for the technical content and has proposed Lifang Xia and Yunhai Shang as port maintainers.  (Note that C-SKY does have a corporate copyright assignment on file with the FSF.) Mentor Graphics' role has been cleaning up the code, adding documentation and additional test cases, etc, to address issues we anticipated reviewers would complain about.

bfd     * Makefile.am (ALL_MACHINES, ALL_MACHINES_CFILES): Add C-SKY.
        (BFD32_BACKENDS, BFD_BACKENDS_CFILES): Likewise.
        * Makefile.in: Regenerated.
        * archures.c (enum bfd_architecture): Add bfd_arch_csky and
        related bfd_mach defines.
        (bfd_csky_arch): Declare.
        (bfd_archures_list): Add C-SKY.
        * bfd-in.h (elf32_csky_build_stubs): Declare.
        (elf32_csky_size_stubs): Declare.
        (elf32_csky_next_input_section: Declare.
        (elf32_csky_setup_section_lists): Declare.
        * bfd-in2.h: Regenerated.
        * config.bfd: Add C-SKY.
        * configure.ac: Likewise.
        * configure: Regenerated.
        * cpu-csky.c: New file.
        * elf-bfd.h (enum elf_target_id): Add C-SKY.
        * elf32-csky.c: New file.
        * libbfd.h: Regenerated.
        * reloc.c: Add C-SKY relocations.
        * targets.c (csky_elf32_be_vec, csky_elf32_le_vec): Declare.
        (_bfd_target_vector): Add C-SKY target vector entries.

binutils* readelf.c: Include elf/csky.h.
        (guess_is_rela): Handle EM_CSKY.
        (dump_relocations): Likewise.
        (get_machine_name): Likewise.
        (is_32bit_abs_reloc): Likewise.

include  * dis-asm.h (csky_symbol_is_valid): Declare.
         * opcode/csky.h: New file.

opcodes  * Makefile.am (TARGET_LIBOPCODES_CFILES): Add csky-dis.c.
         * Makefile.in: Regenerated.
         * configure.ac: Add C-SKY.
         * configure: Regenerated.
         * csky-dis.c: New file.
         * csky-opc.h: New file.
         * disassemble.c (ARCH_csky): Define.
         (disassembler, disassemble_init_for_target): Add case for ARCH_csky.
         * disassemble.h (print_insn_csky, csky_get_disassembler): Declare.

gas      * Makefile.am (TARGET_CPU_CFILES): Add entry for C-SKY.
         (TARGET_CPU_HFILES, TARGET_ENV_HFILES): Likewise.
         * Makefile.in: Regenerated.
         * config/tc-csky.c: New file.
         * config/tc-csky.h: New file.
         * config/te-csky_abiv1.h: New file.
         * config/te-csky_abiv1_linux.h: New file.
         * config/te-csky_abiv2.h: New file.
         * config/te-csky_abiv2_linux.h: New file.
         * configure.tgt: Add C-SKY.
         * doc/Makefile.am (CPU_DOCS): Add entry for C-SKY.
         * doc/Makefile.in: Regenerated.
         * doc/all.texi: Set CSKY feature.
         * doc/as.texi (Overview): Add C-SKY options.
         (Machine Dependencies): Likewise.
         * doc/c-csky.texi: New file.
         * testsuite/gas/csky/*: New test cases.

ld      * Makefile.am (ALL_EMULATION_SOURCES): Add C-SKY emulations.
        (ecskyelf.c, ecskyelf_linux.c): New rules.
        * Makefile.in: Regenerated.
        * configure.tgt: Add C-SKY.
        * emulparams/cskyelf.sh: New file.
        * emulparams/cskyelf_linux.sh: New file.
        * emultempl/cskyelf.em: New file.
        * gen-doc.texi: Add C-SKY.
        * ld.texi: Likewise.
        (Options specific to C-SKY targets): New section.
        * testsuite/ld-csky/*: New tests.

1 files changed, 355 insertions, 0 deletions

diff --git a/ld/emultempl/cskyelf.em b/ld/emultempl/cskyelf.em
new file mode 100644
index 0000000..cd4c3fa
--- /dev/null
+++ b/ld/emultempl/cskyelf.em
@@ -0,0 +1,355 @@
+# This shell script emits a C file. -*- C -*-
+#   Copyright (C) 2013-2018 Free Software Foundation, Inc.
+#
+# This file is part of GNU Binutils.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+# MA 02110-1301, USA.
+
+# This file is sourced from elf32.em, and defines extra C-SKY ELF
+# specific routines.
+#
+fragment <<EOF
+
+#include "ldctor.h"
+#include "elf/csky.h"
+
+/* To use branch stub or not.  */
+extern bfd_boolean use_branch_stub;
+
+/* Fake input file for stubs.  */
+static lang_input_statement_type *stub_file;
+
+/* Whether we need to call gldcsky_layout_sections_again.  */
+static int need_laying_out = 0;
+
+/* Maximum size of a group of input sections that can be handled by
+   one stub section.  A value of +/-1 indicates the bfd back-end
+   should use a suitable default size.  */
+static bfd_signed_vma group_size = 1;
+
+struct hook_stub_info
+{
+  lang_statement_list_type add;
+  asection *input_section;
+};
+
+/* Traverse the linker tree to find the spot where the stub goes.  */
+static bfd_boolean
+hook_in_stub (struct hook_stub_info *info, lang_statement_union_type **lp)
+{
+  lang_statement_union_type *l;
+  bfd_boolean ret;
+
+  for (l = *lp; l != NULL; lp = &l->header.next, l = *lp)
+    switch (l->header.type)
+      {
+      case lang_constructors_statement_enum:
+	ret = hook_in_stub (info, &constructor_list.head);
+	if (ret)
+	  return ret;
+	break;
+
+      case lang_output_section_statement_enum:
+	ret = hook_in_stub (info,
+			    &l->output_section_statement.children.head);
+	if (ret)
+	  return ret;
+	break;
+
+      case lang_wild_statement_enum:
+	ret = hook_in_stub (info, &l->wild_statement.children.head);
+	if (ret)
+	  return ret;
+	break;
+
+      case lang_group_statement_enum:
+	ret = hook_in_stub (info, &l->group_statement.children.head);
+	if (ret)
+	  return ret;
+	break;
+
+      case lang_input_section_enum:
+	if (l->input_section.section == info->input_section)
+	  {
+	    /* We've found our section.  Insert the stub immediately
+	       after its associated input section.  */
+	    *(info->add.tail) = l->header.next;
+	    l->header.next = info->add.head;
+	    return TRUE;
+	  }
+	break;
+
+      case lang_data_statement_enum:
+      case lang_reloc_statement_enum:
+      case lang_object_symbols_statement_enum:
+      case lang_output_statement_enum:
+      case lang_target_statement_enum:
+      case lang_input_statement_enum:
+      case lang_assignment_statement_enum:
+      case lang_padding_statement_enum:
+      case lang_address_statement_enum:
+      case lang_fill_statement_enum:
+	break;
+
+      default:
+	FAIL ();
+	break;
+      }
+
+  return FALSE;
+}
+EOF
+
+case ${target} in
+    csky-*-linux-*)
+fragment <<EOF
+/* This is a convenient point to tell BFD about target specific flags.
+   After the output has been created, but before inputs are read.  */
+static void
+csky_elf_create_output_section_statements (void)
+{
+  use_branch_stub = FALSE;
+}
+EOF
+    ;;
+    *)
+fragment <<EOF
+/* This is a convenient point to tell BFD about target specific flags.
+   After the output has been created, but before inputs are read.  */
+static void
+csky_elf_create_output_section_statements (void)
+{
+  /* If don't use branch stub, just do not emit stub_file.  */
+  if (use_branch_stub == FALSE)
+    return;
+  stub_file = lang_add_input_file ("linker stubs",
+				   lang_input_file_is_fake_enum, NULL);
+  stub_file->the_bfd = bfd_create ("linker stubs", link_info.output_bfd);
+  if (stub_file->the_bfd == NULL
+      || !bfd_set_arch_mach (stub_file->the_bfd,
+	  bfd_get_arch (link_info.output_bfd),
+	  bfd_get_mach (link_info.output_bfd)))
+    {
+      einfo (_("%F%P: can not create BFD: %E\n"));
+      return;
+    }
+
+  stub_file->the_bfd->flags |= BFD_LINKER_CREATED;
+  ldlang_add_file (stub_file);
+}
+EOF
+    ;;
+esac
+
+fragment <<EOF
+/* Call-back for elf32_csky_size_stubs.  */
+
+/* Create a new stub section, and arrange for it to be linked
+   immediately after INPUT_SECTION.  */
+static asection *
+elf32_csky_add_stub_section (const char *stub_sec_name,
+			     asection *input_section)
+{
+  asection *stub_sec;
+  flagword flags;
+  asection *output_section;
+  const char *secname;
+  lang_output_section_statement_type *os;
+  struct hook_stub_info info;
+
+  flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
+	   | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
+  stub_sec = bfd_make_section_anyway_with_flags (stub_file->the_bfd,
+						 stub_sec_name, flags);
+  if (stub_sec == NULL)
+    goto err_ret;
+
+  bfd_set_section_alignment (stub_file->the_bfd, stub_sec, 3);
+
+  output_section = input_section->output_section;
+  secname = bfd_get_section_name (output_section->owner, output_section);
+  os = lang_output_section_find (secname);
+
+  info.input_section = input_section;
+  lang_list_init (&info.add);
+  lang_add_section (&info.add, stub_sec, NULL, os);
+
+  if (info.add.head == NULL)
+    goto err_ret;
+
+  if (hook_in_stub (&info, &os->children.head))
+    return stub_sec;
+
+err_ret:
+  einfo (_("%X%P: can not make stub section: %E\n"));
+  return NULL;
+}
+
+/* Another call-back for elf_csky_size_stubs.  */
+static void
+gldcsky_layout_sections_again (void)
+{
+  /* If we have changed sizes of the stub sections, then we need
+     to recalculate all the section offsets.  This may mean we need to
+     add even more stubs.  */
+  gld${EMULATION_NAME}_map_segments (TRUE);
+  need_laying_out = -1;
+}
+
+static void
+build_section_lists (lang_statement_union_type *statement)
+{
+  if (statement->header.type == lang_input_section_enum)
+    {
+      asection *i = statement->input_section.section;
+
+      if (i->sec_info_type != SEC_INFO_TYPE_JUST_SYMS
+	  && (i->flags & SEC_EXCLUDE) == 0
+	  && i->output_section != NULL
+	  && i->output_section->owner == link_info.output_bfd)
+	elf32_csky_next_input_section (&link_info, i);
+    }
+}
+
+static void
+gld${EMULATION_NAME}_after_allocation (void)
+{
+  /* bfd_elf32_discard_info just plays with debugging sections,
+     ie. doesn't affect any code, so we can delay resizing the
+     sections.  It's likely we'll resize everything in the process of
+     adding stubs.  */
+  if (bfd_elf_discard_info (link_info.output_bfd, &link_info))
+    need_laying_out = 1;
+
+  /* If generating a relocatable output file, then we don't
+     have to examine the relocs.  */
+
+  if (stub_file != NULL && !bfd_link_relocatable (&link_info))
+    {
+      int ret = elf32_csky_setup_section_lists (link_info.output_bfd,
+						&link_info);
+
+      if (ret < 0)
+	{
+	  einfo (_("%X%P: could not compute sections lists for stub generation: %E\n"));
+	  return;
+	}
+      else if (ret != 0)
+	{
+	  lang_for_each_statement (build_section_lists);
+
+	  /* Call into the BFD backend to do the real work.  */
+	  if (! elf32_csky_size_stubs (link_info.output_bfd,
+				       stub_file->the_bfd,
+				       &link_info,
+				       group_size,
+				       &elf32_csky_add_stub_section,
+				       &gldcsky_layout_sections_again))
+	  {
+	    einfo (_("%X%P: cannot size stub section: %E\n"));
+	    return;
+	  }
+	}
+    }
+
+  if (need_laying_out != -1)
+    gld${EMULATION_NAME}_map_segments (need_laying_out);
+}
+
+static void
+gld${EMULATION_NAME}_finish (void)
+{
+  if (stub_file != NULL
+      && !bfd_link_relocatable (&link_info)
+      && stub_file->the_bfd->sections != NULL
+      && !elf32_csky_build_stubs (&link_info))
+    einfo (_("%X%P: cannot build stubs: %E\n"));
+  finish_default ();
+}
+
+/* Avoid processing the fake stub_file in vercheck, stat_needed and
+   check_needed routines.  */
+
+static void (*real_func) (lang_input_statement_type *);
+
+static void csky_for_each_input_file_wrapper (lang_input_statement_type *l)
+{
+  if (l != stub_file)
+    (*real_func) (l);
+}
+
+static void
+csky_lang_for_each_input_file (void (*func) (lang_input_statement_type *))
+{
+  real_func = func;
+  lang_for_each_input_file (&csky_for_each_input_file_wrapper);
+}
+
+#define lang_for_each_input_file csky_lang_for_each_input_file
+
+EOF
+
+# This code gets inserted into the generic elf32.sc linker script
+# and allows us to define our own command line switches.
+case ${target} in
+    csky-*-linux-*)
+    ;;
+
+    *)
+PARSE_AND_LIST_PROLOGUE='
+#define OPTION_BRANCH_STUB		301
+#define OPTION_NO_BRANCH_STUB		302
+#define OPTION_STUBGROUP_SIZE		303
+'
+
+PARSE_AND_LIST_LONGOPTS='
+  {"branch-stub",	no_argument,       NULL, OPTION_BRANCH_STUB},
+  {"no-branch-stub",	no_argument,       NULL, OPTION_NO_BRANCH_STUB},
+  {"stub-group-size",	required_argument, NULL, OPTION_STUBGROUP_SIZE},
+'
+PARSE_AND_LIST_OPTIONS='
+  fprintf (file, _("  --[no-]branch-stub\n"));
+  fprintf (file, _("\t\t\tDisable/enable use of stubs to expand branch "
+		   "instructions that cannot reach the target.\n"));
+  fprintf (file, _("  --stub-group-size=N\n"));
+  fprintf (file, _("\t\t\tMaximum size of a group of input sections "
+		   "handled by one stub section."));
+'
+
+PARSE_AND_LIST_ARGS_CASES='
+  case OPTION_BRANCH_STUB:
+    use_branch_stub = TRUE;
+    break;
+  case OPTION_NO_BRANCH_STUB:
+    use_branch_stub = FALSE;
+    break;
+
+  case OPTION_STUBGROUP_SIZE:
+    {
+      const char *end;
+
+      group_size = bfd_scan_vma (optarg, &end, 0);
+      if (*end)
+	einfo (_("%F%P: invalid number `%s'\''\n"), optarg);
+    }
+    break;
+'
+    ;;
+esac
+
+LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
+LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=csky_elf_create_output_section_statements
+LDEMUL_FINISH=gld${EMULATION_NAME}_finish