Add a fake bfd to hold linker created dynamic sectionsusers/hjl/dynobj

Currently, we hold linker created dynamic sections in an input shared
object, which has its own dynamic sections, when the first input file
from linker is a shared object.  It may lead to conflicts between
linker created dynamic sections and shared object's dynamic sections.
We can use a a fake bfd to hold linker created dynamic sections.
Unfortunately, it doesn't work due to BFD_LINKER_CREATED.  Dynamic
sections in bfd with BFD_LINKER_CREATED may be ignored.

15 files changed, 75 insertions, 28 deletions

diff --git a/bfd/elflink.c b/bfd/elflink.c
index 6f6726648fd..5656ca0ccb6 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -198,31 +198,11 @@ _bfd_elf_create_got_section (bfd *abfd, struct bfd_link_info *info)
 
 /* Create a strtab to hold the dynamic symbol names.  */
 static bfd_boolean
-_bfd_elf_link_create_dynstrtab (bfd *abfd, struct bfd_link_info *info)
+_bfd_elf_link_create_dynstrtab (struct bfd_link_info *info)
 {
   struct elf_link_hash_table *hash_table;
 
   hash_table = elf_hash_table (info);
-  if (hash_table->dynobj == NULL)
-    {
-      /* We may not set dynobj, an input file holding linker created
-	 dynamic sections to abfd, which may be a dynamic object with
-	 its own dynamic sections.  We need to find a normal input file
-	 to hold linker created sections if possible.  */
-      if ((abfd->flags & (DYNAMIC | BFD_PLUGIN)) != 0)
-	{
-	  bfd *ibfd;
-	  for (ibfd = info->input_bfds; ibfd; ibfd = ibfd->link.next)
-	    if ((ibfd->flags
-		 & (DYNAMIC | BFD_LINKER_CREATED | BFD_PLUGIN)) == 0)
-	      {
-		abfd = ibfd;
-		break;
-	      }
-	}
-      hash_table->dynobj = abfd;
-    }
-
   if (hash_table->dynstr == NULL)
     {
       hash_table->dynstr = _bfd_elf_strtab_init ();
@@ -253,7 +233,7 @@ _bfd_elf_link_create_dynamic_sections (bfd *abfd, struct bfd_link_info *info)
   if (elf_hash_table (info)->dynamic_sections_created)
     return TRUE;
 
-  if (!_bfd_elf_link_create_dynstrtab (abfd, info))
+  if (!_bfd_elf_link_create_dynstrtab (info))
     return FALSE;
 
   abfd = elf_hash_table (info)->dynobj;
@@ -3206,15 +3186,14 @@ _bfd_elf_add_dynamic_entry (struct bfd_link_info *info,
    1 if a DT_NEEDED tag already exists, and 0 on success.  */
 
 static int
-elf_add_dt_needed_tag (bfd *abfd,
-		       struct bfd_link_info *info,
+elf_add_dt_needed_tag (struct bfd_link_info *info,
 		       const char *soname,
 		       bfd_boolean do_it)
 {
   struct elf_link_hash_table *hash_table;
   bfd_size_type strindex;
 
-  if (!_bfd_elf_link_create_dynstrtab (abfd, info))
+  if (!_bfd_elf_link_create_dynstrtab (info))
     return -1;
 
   hash_table = elf_hash_table (info);
@@ -3908,7 +3887,7 @@ error_free_dyn:
 	 will need to know it.  */
       elf_dt_name (abfd) = soname;
 
-      ret = elf_add_dt_needed_tag (abfd, info, soname, add_needed);
+      ret = elf_add_dt_needed_tag (info, soname, add_needed);
       if (ret < 0)
 	goto error_return;
 
@@ -4717,7 +4696,7 @@ error_free_dyn:
 		(elf_dyn_lib_class (abfd) & ~DYN_AS_NEEDED);
 
 	      add_needed = TRUE;
-	      ret = elf_add_dt_needed_tag (abfd, info, soname, add_needed);
+	      ret = elf_add_dt_needed_tag (info, soname, add_needed);
 	      if (ret < 0)
 		goto error_free_vers;
 
diff --git a/ld/emultempl/aarch64elf.em b/ld/emultempl/aarch64elf.em
index 9923be3a6b6..c961b9e79bf 100644
--- a/ld/emultempl/aarch64elf.em
+++ b/ld/emultempl/aarch64elf.em
@@ -322,6 +322,8 @@ aarch64_elf_create_output_section_statements (void)
 
   stub_file->the_bfd->flags |= BFD_LINKER_CREATED;
   ldlang_add_file (stub_file);
+
+  gld${EMULATION_NAME}_create_output_section_statements ();
 }
 
 /* Avoid processing the fake stub_file in vercheck, stat_needed and
diff --git a/ld/emultempl/armelf.em b/ld/emultempl/armelf.em
index 2e431720842..b7b94633738 100644
--- a/ld/emultempl/armelf.em
+++ b/ld/emultempl/armelf.em
@@ -514,6 +514,8 @@ arm_elf_create_output_section_statements (void)
   /* Also use the stub file for stubs placed in a single output section.  */
   bfd_elf32_arm_add_glue_sections_to_bfd (stub_file->the_bfd, &link_info);
   bfd_elf32_arm_get_bfd_for_interworking (stub_file->the_bfd, &link_info);
+
+  gld${EMULATION_NAME}_create_output_section_statements ();
 }
 
 /* Avoid processing the fake stub_file in vercheck, stat_needed and
diff --git a/ld/emultempl/avrelf.em b/ld/emultempl/avrelf.em
index 4710b6e0e82..80526aca4c0 100644
--- a/ld/emultempl/avrelf.em
+++ b/ld/emultempl/avrelf.em
@@ -136,6 +136,7 @@ avr_elf_create_output_section_statements (void)
 
   ldlang_add_file (stub_file);
 
+  gld${EMULATION_NAME}_create_output_section_statements ();
   return;
 
   err_ret:
diff --git a/ld/emultempl/elf32.em b/ld/emultempl/elf32.em
index 4f5d1a4d2c0..e90af48455b 100644
--- a/ld/emultempl/elf32.em
+++ b/ld/emultempl/elf32.em
@@ -64,6 +64,7 @@ static void gld${EMULATION_NAME}_after_parse (void);
 static void gld${EMULATION_NAME}_after_open (void);
 static void gld${EMULATION_NAME}_before_allocation (void);
 static void gld${EMULATION_NAME}_after_allocation (void);
+static void gld${EMULATION_NAME}_create_output_section_statements (void);
 static lang_output_section_statement_type *gld${EMULATION_NAME}_place_orphan
   (asection *, const char *, int);
 EOF
@@ -263,6 +264,8 @@ gld${EMULATION_NAME}_stat_needed (lang_input_statement_type *s)
     return;
   if (s->the_bfd == NULL)
     return;
+  if ((s->the_bfd->flags & BFD_LINKER_CREATED) != 0)
+    return;
 
   /* If this input file was an as-needed entry, and wasn't found to be
      needed at the stage it was linked, then don't say we have loaded it.  */
@@ -1400,6 +1403,46 @@ gld${EMULATION_NAME}_find_statement_assignment (lang_statement_union_type *s)
 
 EOF
 
+if test x"$LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS" != xgld"$EMULATION_NAME"create_output_section_statements; then
+fragment <<EOF
+
+/* Fake input file for dynamic sections.  */
+static lang_input_statement_type *dynobj;
+
+/* This is called before the input files are opened.  We create a new
+   fake input file to hold the dynamic sections.  */
+
+static void
+gld${EMULATION_NAME}_create_output_section_statements (void)
+{
+  if (bfd_get_flavour (link_info.output_bfd) != bfd_target_elf_flavour)
+    return;
+
+  dynobj = lang_add_input_file (" dynobj ",
+				lang_input_file_is_fake_enum,
+				NULL);
+  dynobj->the_bfd = bfd_create (" dynobj ", link_info.output_bfd);
+  if (dynobj->the_bfd == NULL
+      || !bfd_set_arch_mach (dynobj->the_bfd,
+			     bfd_get_arch (link_info.output_bfd),
+			     bfd_get_mach (link_info.output_bfd)))
+    {
+      einfo ("%F%P: can not create BFD to hold dynamic sections: %E\n");
+      return;
+    }
+
+  dynobj->the_bfd->flags |= BFD_LINKER_CREATED;
+  elf_elfheader (dynobj->the_bfd)->e_ident[EI_CLASS]
+    = (get_elf_backend_data (link_info.output_bfd)->s->arch_size == 64
+       ? ELFCLASS64 : ELFCLASS32);
+  elf_hash_table (&link_info)->dynobj = dynobj->the_bfd;
+
+  ldlang_add_file (dynobj);
+}
+
+EOF
+fi
+
 if test x"$LDEMUL_BEFORE_ALLOCATION" != xgld"$EMULATION_NAME"_before_allocation; then
   if test x"${ELF_INTERPRETER_NAME+set}" = xset; then
     ELF_INTERPRETER_SET_DEFAULT="
@@ -2515,7 +2558,7 @@ struct ld_emulation_xfer_struct ld_${EMULATION_NAME}_emulation =
   "${EMULATION_NAME}",
   "${OUTPUT_FORMAT}",
   ${LDEMUL_FINISH-finish_default},
-  ${LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS-NULL},
+  ${LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS-gld${EMULATION_NAME}_create_output_section_statements},
   ${LDEMUL_OPEN_DYNAMIC_ARCHIVE-gld${EMULATION_NAME}_open_dynamic_archive},
   ${LDEMUL_PLACE_ORPHAN-gld${EMULATION_NAME}_place_orphan},
   ${LDEMUL_SET_SYMBOLS-NULL},
diff --git a/ld/emultempl/hppaelf.em b/ld/emultempl/hppaelf.em
index a1d2e80d2a8..5965e9b1cfd 100644
--- a/ld/emultempl/hppaelf.em
+++ b/ld/emultempl/hppaelf.em
@@ -88,6 +88,8 @@ hppaelf_create_output_section_statements (void)
 
   stub_file->the_bfd->flags |= BFD_LINKER_CREATED;
   ldlang_add_file (stub_file);
+
+  gld${EMULATION_NAME}_create_output_section_statements ();
 }
 
 
diff --git a/ld/emultempl/m68hc1xelf.em b/ld/emultempl/m68hc1xelf.em
index 739479d7e51..b2e8fa1b7c7 100644
--- a/ld/emultempl/m68hc1xelf.em
+++ b/ld/emultempl/m68hc1xelf.em
@@ -155,6 +155,8 @@ m68hc11elf_create_output_section_statements (void)
     }
 
   ldlang_add_file (stub_file);
+
+  gld${EMULATION_NAME}_create_output_section_statements ();
 }
 
 
diff --git a/ld/emultempl/m68kelf.em b/ld/emultempl/m68kelf.em
index c1a514c5a8f..17150acb51d 100644
--- a/ld/emultempl/m68kelf.em
+++ b/ld/emultempl/m68kelf.em
@@ -208,6 +208,8 @@ static void
 elf_m68k_create_output_section_statements (void)
 {
   bfd_elf_m68k_set_target_options (&link_info, got_handling);
+
+  gld${EMULATION_NAME}_create_output_section_statements ();
 }
 
 EOF
diff --git a/ld/emultempl/metagelf.em b/ld/emultempl/metagelf.em
index 5626ecad830..95900d70829 100644
--- a/ld/emultempl/metagelf.em
+++ b/ld/emultempl/metagelf.em
@@ -65,6 +65,8 @@ metagelf_create_output_section_statements (void)
 
   stub_file->the_bfd->flags |= BFD_LINKER_CREATED;
   ldlang_add_file (stub_file);
+
+  gld${EMULATION_NAME}_create_output_section_statements ();
 }
 
 
diff --git a/ld/emultempl/mipself.em b/ld/emultempl/mipself.em
index dbff36bb8d1..d64ca0db71b 100644
--- a/ld/emultempl/mipself.em
+++ b/ld/emultempl/mipself.em
@@ -206,6 +206,8 @@ mips_create_output_section_statements (void)
 
   if (is_mips_elf (link_info.output_bfd))
     _bfd_mips_elf_init_stubs (&link_info, mips_add_stub_section);
+
+  gld${EMULATION_NAME}_create_output_section_statements ();
 }
 
 /* This is called after we have merged the private data of the input bfds.  */
diff --git a/ld/emultempl/nds32elf.em b/ld/emultempl/nds32elf.em
index 08da695bac0..eee5087c503 100644
--- a/ld/emultempl/nds32elf.em
+++ b/ld/emultempl/nds32elf.em
@@ -65,6 +65,8 @@ nds32_elf_create_output_section_statements (void)
 				     ex9_export_file, ex9_import_file,
 				     update_ex9_table, ex9_limit,
 				     ex9_loop_aware, ifc_loop_aware);
+
+  gld${EMULATION_NAME}_create_output_section_statements ();
 }
 
 static void
diff --git a/ld/emultempl/nios2elf.em b/ld/emultempl/nios2elf.em
index da4bea05d96..3b1275c70f6 100644
--- a/ld/emultempl/nios2elf.em
+++ b/ld/emultempl/nios2elf.em
@@ -70,6 +70,8 @@ nios2elf_create_output_section_statements (void)
 
   stub_file->the_bfd->flags |= BFD_LINKER_CREATED;
   ldlang_add_file (stub_file);
+
+  gld${EMULATION_NAME}_create_output_section_statements ();
 }
 
 
diff --git a/ld/emultempl/ppc32elf.em b/ld/emultempl/ppc32elf.em
index a0255cd5323..37dcc953f90 100644
--- a/ld/emultempl/ppc32elf.em
+++ b/ld/emultempl/ppc32elf.em
@@ -53,6 +53,8 @@ ppc_after_open_output (void)
     pagesize = config.commonpagesize;
   params.pagesize_p2 = bfd_log2 (pagesize);
   ppc_elf_link_params (&link_info, &params);
+
+  gld${EMULATION_NAME}_create_output_section_statements ();
 }
 
 EOF
diff --git a/ld/emultempl/ppc64elf.em b/ld/emultempl/ppc64elf.em
index d7c0686d681..1f48ab1f930 100644
--- a/ld/emultempl/ppc64elf.em
+++ b/ld/emultempl/ppc64elf.em
@@ -98,6 +98,8 @@ ppc_create_output_section_statements (void)
     params.save_restore_funcs = !bfd_link_relocatable (&link_info);
   if (!ppc64_elf_init_stub_bfd (&link_info, &params))
     einfo ("%F%P: can not init BFD: %E\n");
+
+  gld${EMULATION_NAME}_create_output_section_statements ();
 }
 
 /* Called after opening files but before mapping sections.  */
diff --git a/ld/emultempl/rxelf.em b/ld/emultempl/rxelf.em
index 36be1ba6cc0..d1fc9fa0831 100644
--- a/ld/emultempl/rxelf.em
+++ b/ld/emultempl/rxelf.em
@@ -38,6 +38,8 @@ rx_elf_create_output_section_statements (void)
   extern void bfd_elf32_rx_set_target_flags (bfd_boolean, bfd_boolean);
 
   bfd_elf32_rx_set_target_flags (no_flag_mismatch_warnings, ignore_lma);
+
+  gld${EMULATION_NAME}_create_output_section_statements ();
 }
 
 EOF