elf: Strip zero-sized dynamic sections
[deliverable/binutils-gdb.git] / ld / emultempl / hppaelf.em
index dd3b264a444bda215f9a99d0175b62e7ce144fd0..7c47e9918f2f04df43b531fd77840f458dd8452f 100644 (file)
 # This shell script emits a C file. -*- C -*-
-# It does some substitutions.
-cat >e${EMULATION_NAME}.c <<EOF
-/* An emulation for HP PA-RISC ELF linkers.
-   Copyright (C) 1991, 93, 94, 95, 97, 1999 Free Software Foundation, Inc.
-   Written by Steve Chamberlain steve@cygnus.com
-
-This file is part of GLD, the Gnu Linker.
-
-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 2 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
-
-#include "bfd.h"
-#include "sysdep.h"
-#include "bfdlink.h"
-
-#include "ld.h"
-#include "ldemul.h"
-#include "ldfile.h"
-#include "ldexp.h"
-#include "ldlang.h"
-#include "ldmisc.h"
-#include "ldmain.h"
+#   Copyright (C) 1991-2020 Free Software Foundation, Inc.
+#
+# This file is part of the 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 elf.em, and defines extra hppa-elf
+# specific routines.
+#
+fragment <<EOF
+
 #include "ldctor.h"
+#include "elf32-hppa.h"
+
 
-/* Section in which we build stubs.  */
-static asection *stub_sec;
+/* Fake input file for stubs.  */
 static lang_input_statement_type *stub_file;
 
+/* Type of import/export stubs to build.  For a single sub-space model,
+   we can build smaller import stubs and there is no need for export
+   stubs.  */
+static int multi_subspace = 0;
 
-/* FIXME.  This doesn't belong here.  */
-extern lang_statement_list_type file_chain;
+/* Whether we need to call hppa_layout_sections_again.  */
+static int need_laying_out = 0;
 
-/* Perform some emulation specific initialization.  For PA ELF we set
-   up the local label prefix and the output architecture.  */
+/* 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;
 
-static void
-hppaelf_before_parse ()
-{
-  ldfile_output_architecture = bfd_arch_hppa;
-}
-
-/* Set the output architecture and machine.  */
+/* Stops the linker merging .text sections on a relocatable link,
+   and adds millicode library to the list of input files.  */
 
 static void
-hppaelf_set_output_arch()
+hppaelf_after_parse (void)
 {
-  unsigned long machine = 0;
+  if (bfd_link_relocatable (&link_info))
+    lang_add_unique (".text");
+
+  /* Enable this once we split millicode stuff from libgcc:
+     lang_add_input_file ("milli",
+                         lang_input_file_is_l_enum,
+                         NULL);
+  */
 
-  bfd_set_arch_mach (output_bfd, ldfile_output_architecture, machine);
+  ldelf_after_parse ();
 }
 
 /* This is called before the input files are opened.  We create a new
-   fake input file to hold the stub section.  */
+   fake input file to hold the stub sections.  */
 
 static void
-hppaelf_create_output_section_statements ()
+hppaelf_create_output_section_statements (void)
 {
+  if (!(bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour
+       && (elf_object_id (link_info.output_bfd) == HPPA32_ELF_DATA
+           || elf_object_id (link_info.output_bfd) == HPPA64_ELF_DATA)))
+    return;
+
   stub_file = lang_add_input_file ("linker stubs",
                                   lang_input_file_is_fake_enum,
                                   NULL);
-  stub_file->the_bfd = bfd_create ("linker stubs", output_bfd);
+  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 (output_bfd),
-                             bfd_get_mach (output_bfd)))
-    {
-      einfo ("%X%P: can not create BFD %E\n");
-      return;
-    }
-
-  stub_sec = bfd_make_section_old_way (stub_file->the_bfd, ".text");
-  /* Don't set SEC_RELOC until we actually have relocations in this
-     section.  */
-  if (stub_sec == NULL
-      || ! bfd_set_section_flags (stub_file->the_bfd, stub_sec,
-                                 (SEC_HAS_CONTENTS
-                                  | SEC_ALLOC
-                                  | SEC_LOAD
-                                  | SEC_CODE
-                                  | SEC_IN_MEMORY)))
+                             bfd_get_arch (link_info.output_bfd),
+                             bfd_get_mach (link_info.output_bfd)))
     {
-      einfo ("%X%P: can not create stub section: %E\n");
+      einfo (_("%F%P: can not create BFD: %E\n"));
       return;
     }
 
+  stub_file->the_bfd->flags |= BFD_LINKER_CREATED;
   ldlang_add_file (stub_file);
+  elf32_hppa_init_stub_bfd (stub_file->the_bfd, &link_info);
 }
 
-/* Walk all the lang statements splicing out any padding statements from 
-   the list.  */
 
-static void
-hppaelf_delete_padding_statements (s, prev)
-     lang_statement_union_type *s;
-     lang_statement_union_type **prev;
+struct hook_stub_info
 {
-  lang_statement_union_type *sprev = NULL;
-  for (; s != NULL; s = s->next)
+  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) != NULL; lp = &l->header.next)
     {
-      switch (s->header.type)
+      switch (l->header.type)
        {
-
-       /* We want recursively walk these sections.  */
        case lang_constructors_statement_enum:
-         hppaelf_delete_padding_statements (constructor_list.head,
-                                            &constructor_list.head);
+         ret = hook_in_stub (info, &constructor_list.head);
+         if (ret)
+           return ret;
          break;
 
        case lang_output_section_statement_enum:
-         hppaelf_delete_padding_statements (s->output_section_statement.
-                                              children.head,
-                                            &s->output_section_statement.
-                                              children.head);
+         ret = hook_in_stub (info,
+                             &l->output_section_statement.children.head);
+         if (ret)
+           return ret;
          break;
 
-       /* Huh?  What is a lang_wild_statement?  */
        case lang_wild_statement_enum:
-         hppaelf_delete_padding_statements (s->wild_statement.
-                                              children.head,
-                                            &s->wild_statement.
-                                              children.head);
+         ret = hook_in_stub (info, &l->wild_statement.children.head);
+         if (ret)
+           return ret;
          break;
 
-       /* Here's what we are really looking for.  Splice these out of
-          the list.  */
-       case lang_padding_statement_enum:
-         if (sprev)
-           sprev->header.next = s->header.next;
-         else
-           **prev = *s;
+       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
+                before its associated input section.  */
+             *lp = info->add.head;
+             *(info->add.tail) = l;
+             return TRUE;
+           }
          break;
 
-       /* We don't care about these cases.  */
        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_section_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:
-         abort ();
+         FAIL ();
          break;
        }
-      sprev = s;
     }
+  return FALSE;
 }
 
-/* Final emulation specific call.  For the PA we use this opportunity
-   to build linker stubs.  */
+
+/* Call-back for elf32_hppa_size_stubs.  */
+
+/* Create a new stub section, and arrange for it to be linked
+   immediately before INPUT_SECTION.  */
+
+static asection *
+hppaelf_add_stub_section (const char *stub_sec_name, asection *input_section)
+{
+  asection *stub_sec;
+  flagword flags;
+  asection *output_section;
+  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;
+
+  output_section = input_section->output_section;
+  os = lang_output_section_get (output_section);
+
+  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 elf32_hppa_size_stubs.  */
 
 static void
-hppaelf_finish ()
+hppaelf_layout_sections_again (void)
 {
-  /* Call into the BFD backend to do the real work.  */
-  if (elf32_hppa_size_stubs (stub_file->the_bfd, output_bfd, &link_info)
-      == false)
-    {
-      einfo ("%X%P: can not size stub section: %E\n");
-      return;
-    }
-  
-  /* If the size of the stub section is nonzero, then we need
-     to resize the sections, recompute the assignments, and finally
-     build the stubs.  */
-  if (bfd_section_size (stub_file->the_bfd, stub_file->the_bfd->sections) != 0)
+  /* 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.  */
+  ldelf_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)
     {
-      /* Delete all the padding statements, they're no longer valid.  */
-      hppaelf_delete_padding_statements (stat_ptr->head, &stat_ptr->head);
-      
-      /* Resize the sections.  */
-      lang_size_sections (stat_ptr->head, abs_output_section,
-                         &stat_ptr->head, 0, (bfd_vma) 0, false);
-      
-      /* Redo special stuff.  */
-      ldemul_after_allocation ();
-      
-      /* Do the assignments again.  */
-      lang_do_assignments (stat_ptr->head,
-                          abs_output_section,
-                          (fill_type) 0, (bfd_vma) 0);
-      
-      /* Now build the linker stubs.  */
-      if (elf32_hppa_build_stubs (stub_file->the_bfd, &link_info) == false)
+      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)
        {
-         einfo ("%X%P: can not build stubs: %E\n");
-         return;
+         elf32_hppa_next_input_section (&link_info, i);
        }
     }
 }
 
-/* The script itself gets inserted here.  */
 
-static char *
-hppaelf_get_script(isfile)
-     int *isfile;
-EOF
+/* For the PA we use this opportunity to size and build linker stubs.  */
 
-if test -n "$COMPILE_IN"
-then
-# Scripts compiled in.
-
-# sed commands to quote an ld script as a C string.
-sc="-f stringify.sed"
+static void
+gld${EMULATION_NAME}_after_allocation (void)
+{
+  int ret;
+
+  /* bfd_elf_discard_info just plays with data and debugging sections,
+     ie. doesn't affect code size, so we can delay resizing the
+     sections.  It's likely we'll resize everything in the process of
+     adding stubs.  */
+  ret = bfd_elf_discard_info (link_info.output_bfd, &link_info);
+  if (ret < 0)
+    {
+      einfo (_("%X%P: .eh_frame/.stab edit: %E\n"));
+      return;
+    }
+  else if (ret > 0)
+    need_laying_out = 1;
 
-cat >>e${EMULATION_NAME}.c <<EOF
-{                           
-  *isfile = 0;
+  /* If generating a relocatable output file, then we don't
+     have to examine the relocs.  */
+  if (stub_file != NULL && !bfd_link_relocatable (&link_info))
+    {
+      ret = elf32_hppa_setup_section_lists (link_info.output_bfd, &link_info);
+      if (ret != 0)
+       {
+         if (ret < 0)
+           {
+             einfo (_("%X%P: can not size stub section: %E\n"));
+             return;
+           }
+
+         lang_for_each_statement (build_section_lists);
+
+         /* Call into the BFD backend to do the real work.  */
+         if (! elf32_hppa_size_stubs (link_info.output_bfd,
+                                      stub_file->the_bfd,
+                                      &link_info,
+                                      multi_subspace,
+                                      group_size,
+                                      &hppaelf_add_stub_section,
+                                      &hppaelf_layout_sections_again))
+           {
+             einfo (_("%X%P: can not size stub section: %E\n"));
+             return;
+           }
+       }
+    }
 
-  if (link_info.relocateable == true && config.build_constructors == true)
-    return
-EOF
-sed $sc ldscripts/${EMULATION_NAME}.xu                     >> e${EMULATION_NAME}.c
-echo '  ; else if (link_info.relocateable == true) return' >> e${EMULATION_NAME}.c
-sed $sc ldscripts/${EMULATION_NAME}.xr                     >> e${EMULATION_NAME}.c
-echo '  ; else if (!config.text_read_only) return'         >> e${EMULATION_NAME}.c
-sed $sc ldscripts/${EMULATION_NAME}.xbn                    >> e${EMULATION_NAME}.c
-echo '  ; else if (!config.magic_demand_paged) return'     >> e${EMULATION_NAME}.c
-sed $sc ldscripts/${EMULATION_NAME}.xn                     >> e${EMULATION_NAME}.c
-echo '  ; else return'                                     >> e${EMULATION_NAME}.c
-sed $sc ldscripts/${EMULATION_NAME}.x                      >> e${EMULATION_NAME}.c
-echo '; }'                                                 >> e${EMULATION_NAME}.c
-
-else
-# Scripts read from the filesystem.
-
-cat >>e${EMULATION_NAME}.c <<EOF
-{                           
-  *isfile = 1;
-
-  if (link_info.relocateable == true && config.build_constructors == true)
-    return "ldscripts/${EMULATION_NAME}.xu";
-  else if (link_info.relocateable == true)
-    return "ldscripts/${EMULATION_NAME}.xr";
-  else if (!config.text_read_only)
-    return "ldscripts/${EMULATION_NAME}.xbn";
-  else if (!config.magic_demand_paged)
-    return "ldscripts/${EMULATION_NAME}.xn";
-  else
-    return "ldscripts/${EMULATION_NAME}.x";
-}
-EOF
+  if (need_laying_out != -1)
+    ldelf_map_segments (need_laying_out);
 
-fi
+  if (!bfd_link_relocatable (&link_info))
+    {
+      /* Set the global data pointer.  */
+      if (! elf32_hppa_set_gp (link_info.output_bfd, &link_info))
+       {
+         einfo (_("%X%P: can not set gp\n"));
+         return;
+       }
 
-cat >>e${EMULATION_NAME}.c <<EOF
+      /* Now build the linker stubs.  */
+      if (stub_file != NULL && stub_file->the_bfd->sections != NULL)
+       {
+         if (! elf32_hppa_build_stubs (&link_info))
+           einfo (_("%X%P: can not build stubs: %E\n"));
+       }
+    }
+}
 
-struct ld_emulation_xfer_struct ld_hppaelf_emulation = 
-{
-  hppaelf_before_parse,
-  syslib_default,
-  hll_default,
-  after_parse_default,
-  after_open_default,
-  after_allocation_default,
-  hppaelf_set_output_arch,
-  ldemul_default_target,
-  before_allocation_default,
-  hppaelf_get_script,
-  "hppaelf",
-  "elf32-hppa",
-  hppaelf_finish,
-  hppaelf_create_output_section_statements,
-  NULL,        /* open dynamic archive */
-  NULL,        /* place orphan */
-  NULL,        /* set symbols */
-  NULL,        /* parse args */
-  NULL,        /* unrecognized file */
-  NULL,        /* list options */
-  NULL         /* recognized file */
-};
 EOF
+
+# Define some shell vars to insert bits of code into the standard elf
+# parse_args and list_options functions.
+#
+PARSE_AND_LIST_PROLOGUE='
+#define OPTION_MULTI_SUBSPACE          301
+#define OPTION_STUBGROUP_SIZE          (OPTION_MULTI_SUBSPACE + 1)
+'
+
+PARSE_AND_LIST_LONGOPTS='
+  { "multi-subspace", no_argument, NULL, OPTION_MULTI_SUBSPACE },
+  { "stub-group-size", required_argument, NULL, OPTION_STUBGROUP_SIZE },
+'
+
+PARSE_AND_LIST_OPTIONS='
+  fprintf (file, _("\
+  --multi-subspace            Generate import and export stubs to support\n\
+                                multiple sub-space shared libraries\n"
+                  ));
+  fprintf (file, _("\
+  --stub-group-size=N         Maximum size of a group of input sections that\n\
+                                can be handled by one stub section.  A negative\n\
+                                value locates all stubs before their branches\n\
+                                (with a group size of -N), while a positive\n\
+                                value allows two groups of input sections, one\n\
+                                before, and one after each stub section.\n\
+                                Values of +/-1 indicate the linker should\n\
+                                choose suitable defaults.\n"
+                  ));
+'
+
+PARSE_AND_LIST_ARGS_CASES='
+    case OPTION_MULTI_SUBSPACE:
+      multi_subspace = 1;
+      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;
+'
+
+# Put these extra hppaelf routines in ld_${EMULATION_NAME}_emulation
+#
+LDEMUL_AFTER_PARSE=hppaelf_after_parse
+LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
+LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=hppaelf_create_output_section_statements
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