[PATCH] ld: Add a before_plugin_all_symbols_read hook

[PATCH] ld: Add a before_plugin_all_symbols_read hook

[H.J. Lu]

Add a before_plugin_all_symbols_read hook to load symbol references from
DT_NEEDED entries, included from --copy-dt-needed-entries, before reading
plugin symbols to properly resolve plugin symbol references.

bfd/

	PR ld/28849
	* elf-bfd.h (elf_link_hash_table): Add
	before_plugin_all_symbols_read.
	* elflink.c (_bfd_elf_merge_symbol): Don't set non_ir_ref_dynamic
	before plugin 'all symbols read' hook is called.

ld/

	PR ld/28849
	* ldelf.c (ldelf_handle_dt_needed): New function.
	(ldelf_before_plugin_all_symbols_read): Likewise.
	(ldelf_after_open): Call ldelf_handle_dt_needed.
	* ldelf.h (ldelf_before_plugin_all_symbols_read): New.
	* ldemul.c (ldemul_before_plugin_all_symbols_read): Likewise.
	* ldemul.h (ldemul_before_plugin_all_symbols_read): Likewise.
	(ld_emulation_xfer_struct): Add before_plugin_all_symbols_read.
	* ldlang.c (lang_process): Call
	ldemul_before_plugin_all_symbols_read before calling
	plugin_call_all_symbols_read.
	* emultempl/elf.em
	(gld${EMULATION_NAME}_before_plugin_all_symbols_read): New.
	(LDEMUL_BEFORE_PLUGIN_ALL_SYMBOLS_READ): New.
	* emultempl/emulation.em (ld_${EMULATION_NAME}_emulation):
	Initialize the before_plugin_all_symbols_read field.
	* testsuite/ld-plugin/lto.exp: Run PR ld/28849 tests.
	* testsuite/ld-plugin/pr28849.d: New file.
	* testsuite/ld-plugin/pr28849a.c: Likewise.
	* testsuite/ld-plugin/pr28849b.c: Likewise.
---
 bfd/elf-bfd.h                     |   3 +
 bfd/elflink.c                     |   8 +-
 ld/emultempl/elf.em               |  14 ++
 ld/emultempl/emulation.em         |   1 +
 ld/ldelf.c                        | 386 ++++++++++++++++--------------
 ld/ldelf.h                        |   2 +
 ld/ldemul.c                       |   7 +
 ld/ldemul.h                       |   5 +
 ld/ldlang.c                       |   2 +
 ld/testsuite/ld-plugin/lto.exp    |  25 ++
 ld/testsuite/ld-plugin/pr28849.d  |   3 +
 ld/testsuite/ld-plugin/pr28849a.c |   2 +
 ld/testsuite/ld-plugin/pr28849b.c |   3 +
 13 files changed, 285 insertions(+), 176 deletions(-)
 create mode 100644 ld/testsuite/ld-plugin/pr28849.d
 create mode 100644 ld/testsuite/ld-plugin/pr28849a.c
 create mode 100644 ld/testsuite/ld-plugin/pr28849b.c

diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
index 889a4746371..16dd00c1a2a 100644
--- a/bfd/elf-bfd.h
+++ b/bfd/elf-bfd.h
@@ -599,6 +599,9 @@ struct elf_link_hash_table
   /* TRUE if DT_JMPREL is a required dynamic tag.  */
   bool dt_jmprel_required;
 
+  /* TRUE before linker calls plugin 'all symbols read' hook.  */
+  bool before_plugin_all_symbols_read;
+
   /* The BFD used to hold special sections created by the linker.
      This will be the first BFD found which requires these sections to
      be created.  */
diff --git a/bfd/elflink.c b/bfd/elflink.c
index f8521426cad..bee8b607a50 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -1090,6 +1090,7 @@ _bfd_elf_merge_symbol (bfd *abfd,
   const struct elf_backend_data *bed;
   char *new_version;
   bool default_sym = *matched;
+  struct elf_link_hash_table *htab;
 
   *skip = false;
   *override = NULL;
@@ -1220,6 +1221,8 @@ _bfd_elf_merge_symbol (bfd *abfd,
      symbols.  */
   bfd_elf_link_mark_dynamic_symbol (info, h, sym);
 
+  htab = elf_hash_table (info);
+
   /* NEWDYN and OLDDYN indicate whether the new or old symbol,
      respectively, is from a dynamic object.  */
 
@@ -1283,7 +1286,10 @@ _bfd_elf_merge_symbol (bfd *abfd,
       olddyn = (oldsec->symbol->flags & BSF_DYNAMIC) != 0;
     }
 
-  if (oldbfd != NULL
+  /* Set non_ir_ref_dynamic only after calling plugin 'all symbols read'
+     hook.  */
+  if (!htab->before_plugin_all_symbols_read
+      && oldbfd != NULL
       && (oldbfd->flags & BFD_PLUGIN) != (abfd->flags & BFD_PLUGIN))
     {
       if (newdyn != olddyn)
diff --git a/ld/emultempl/elf.em b/ld/emultempl/elf.em
index 55dd20f0b02..7ae6f6d50e1 100644
--- a/ld/emultempl/elf.em
+++ b/ld/emultempl/elf.em
@@ -53,6 +53,8 @@ fragment <<EOF
 
 /* Declare functions used by various EXTRA_EM_FILEs.  */
 static void gld${EMULATION_NAME}_before_parse (void);
+static void gld${EMULATION_NAME}_before_plugin_all_symbols_read
+  (void);
 static void gld${EMULATION_NAME}_after_open (void);
 static void gld${EMULATION_NAME}_before_allocation (void);
 static void gld${EMULATION_NAME}_after_allocation (void);
@@ -125,6 +127,17 @@ if test x"$LDEMUL_AFTER_OPEN" != xgld"$EMULATION_NAME"_after_open; then
 
 fragment <<EOF
 
+/* This is called before calling plugin 'all symbols read' hook.  */
+
+static void
+gld${EMULATION_NAME}_before_plugin_all_symbols_read (void)
+{
+  ldelf_before_plugin_all_symbols_read ($IS_LIBPATH, $IS_NATIVE,
+				        $IS_LINUX_TARGET,
+					$IS_FREEBSD_TARGET,
+					$ELFSIZE, "$prefix");
+}
+
 /* This is called after all the input files have been opened.  */
 
 static void
@@ -910,6 +923,7 @@ fi
 fi
 
 LDEMUL_AFTER_PARSE=${LDEMUL_AFTER_PARSE-ldelf_after_parse}
+LDEMUL_BEFORE_PLUGIN_ALL_SYMBOLS_READ=${LDEMUL_BEFORE_PLUGIN_ALL_SYMBOLS_READ-gld${EMULATION_NAME}_before_plugin_all_symbols_read}
 LDEMUL_AFTER_OPEN=${LDEMUL_AFTER_OPEN-gld${EMULATION_NAME}_after_open}
 LDEMUL_BEFORE_PLACE_ORPHANS=${LDEMUL_BEFORE_PLACE_ORPHANS-ldelf_before_place_orphans}
 LDEMUL_AFTER_ALLOCATION=${LDEMUL_AFTER_ALLOCATION-gld${EMULATION_NAME}_after_allocation}
diff --git a/ld/emultempl/emulation.em b/ld/emultempl/emulation.em
index cfa6567ac2b..7fe821a519d 100644
--- a/ld/emultempl/emulation.em
+++ b/ld/emultempl/emulation.em
@@ -8,6 +8,7 @@ struct ld_emulation_xfer_struct ld_${EMULATION_NAME}_emulation =
   ${LDEMUL_SYSLIB-syslib_default},
   ${LDEMUL_HLL-hll_default},
   ${LDEMUL_AFTER_PARSE-after_parse_default},
+  ${LDEMUL_BEFORE_PLUGIN_ALL_SYMBOLS_READ-NULL},
   ${LDEMUL_AFTER_OPEN-after_open_default},
   ${LDEMUL_AFTER_CHECK_RELOCS-after_check_relocs_default},
   ${LDEMUL_BEFORE_PLACE_ORPHANS-before_place_orphans_default},
diff --git a/ld/ldelf.c b/ld/ldelf.c
index 33c6a9f1f46..8ba2eef18f4 100644
--- a/ld/ldelf.c
+++ b/ld/ldelf.c
@@ -1005,173 +1005,15 @@ ldelf_check_needed (lang_input_statement_type *s)
     }
 }
 
-/* This is called after all the input files have been opened.  */
-
-void
-ldelf_after_open (int use_libpath, int native, int is_linux, int is_freebsd,
-		  int elfsize, const char *prefix)
+static void
+ldelf_handle_dt_needed (struct elf_link_hash_table *htab,
+			int use_libpath, int native, int is_linux,
+			int is_freebsd, int elfsize, const char *prefix)
 {
   struct bfd_link_needed_list *needed, *l;
-  struct elf_link_hash_table *htab;
-  asection *s;
   bfd *abfd;
   bfd **save_input_bfd_tail;
 
-  after_open_default ();
-
-  htab = elf_hash_table (&link_info);
-  if (!is_elf_hash_table (&htab->root))
-    return;
-
-  if (command_line.out_implib_filename)
-    {
-      unlink_if_ordinary (command_line.out_implib_filename);
-      link_info.out_implib_bfd
-	= bfd_openw (command_line.out_implib_filename,
-		     bfd_get_target (link_info.output_bfd));
-
-      if (link_info.out_implib_bfd == NULL)
-	{
-	  einfo (_("%F%P: %s: can't open for writing: %E\n"),
-		 command_line.out_implib_filename);
-	}
-    }
-
-  if (ldelf_emit_note_gnu_build_id != NULL)
-    {
-      /* Find an ELF input.  */
-      for (abfd = link_info.input_bfds;
-	   abfd != (bfd *) NULL; abfd = abfd->link.next)
-	if (bfd_get_flavour (abfd) == bfd_target_elf_flavour
-	    && bfd_count_sections (abfd) != 0
-	    && !bfd_input_just_syms (abfd))
-	  break;
-
-      /* PR 10555: If there are no ELF input files do not try to
-	 create a .note.gnu-build-id section.  */
-      if (abfd == NULL
-	  || !ldelf_setup_build_id (abfd))
-	{
-	  free ((char *) ldelf_emit_note_gnu_build_id);
-	  ldelf_emit_note_gnu_build_id = NULL;
-	}
-    }
-
-  get_elf_backend_data (link_info.output_bfd)->setup_gnu_properties (&link_info);
-
-  /* Do not allow executable files to be used as inputs to the link.  */
-  for (abfd = link_info.input_bfds; abfd; abfd = abfd->link.next)
-    {
-      /* Discard input .note.gnu.build-id sections.  */
-      s = bfd_get_section_by_name (abfd, ".note.gnu.build-id");
-      while (s != NULL)
-	{
-	  if (s != elf_tdata (link_info.output_bfd)->o->build_id.sec)
-	    s->flags |= SEC_EXCLUDE;
-	  s = bfd_get_next_section_by_name (NULL, s);
-	}
-
-      if (abfd->xvec->flavour == bfd_target_elf_flavour
-	  && !bfd_input_just_syms (abfd)
-	  && elf_tdata (abfd) != NULL
-	  /* FIXME: Maybe check for other non-supportable types as well ?  */
-	  && (elf_tdata (abfd)->elf_header->e_type == ET_EXEC
-	      || (elf_tdata (abfd)->elf_header->e_type == ET_DYN
-		  && elf_tdata (abfd)->is_pie)))
-	einfo (_("%F%P: cannot use executable file '%pB' as input to a link\n"),
-	       abfd);
-    }
-
-  if (bfd_link_relocatable (&link_info))
-    {
-      if (link_info.execstack == !link_info.noexecstack)
-	{
-	  /* PR ld/16744: If "-z [no]execstack" has been specified on the
-	     command line and we are perfoming a relocatable link then no
-	     PT_GNU_STACK segment will be created and so the
-	     linkinfo.[no]execstack values set in _handle_option() will have no
-	     effect.  Instead we create a .note.GNU-stack section in much the
-	     same way as the assembler does with its --[no]execstack option.  */
-	  flagword flags = SEC_READONLY | (link_info.execstack ? SEC_CODE : 0);
-	  (void) bfd_make_section_with_flags (link_info.input_bfds,
-					      ".note.GNU-stack", flags);
-	}
-      return;
-    }
-
-  if (!link_info.traditional_format)
-    {
-      bfd *elfbfd = NULL;
-      bool warn_eh_frame = false;
-      int seen_type = 0;
-
-      for (abfd = link_info.input_bfds; abfd; abfd = abfd->link.next)
-	{
-	  int type = 0;
-
-	  if (bfd_input_just_syms (abfd))
-	    continue;
-
-	  for (s = abfd->sections; s && type < COMPACT_EH_HDR; s = s->next)
-	    {
-	      const char *name = bfd_section_name (s);
-
-	      if (bfd_is_abs_section (s->output_section))
-		continue;
-	      if (startswith (name, ".eh_frame_entry"))
-		type = COMPACT_EH_HDR;
-	      else if (strcmp (name, ".eh_frame") == 0 && s->size > 8)
-		type = DWARF2_EH_HDR;
-	    }
-
-	  if (type != 0)
-	    {
-	      if (seen_type == 0)
-		{
-		  seen_type = type;
-		}
-	      else if (seen_type != type)
-		{
-		  einfo (_("%F%P: compact frame descriptions incompatible with"
-			   " DWARF2 .eh_frame from %pB\n"),
-			 type == DWARF2_EH_HDR ? abfd : elfbfd);
-		  break;
-		}
-
-	      if (!elfbfd
-		  && (type == COMPACT_EH_HDR
-		      || link_info.eh_frame_hdr_type != 0))
-		{
-		  if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
-		    elfbfd = abfd;
-
-		  warn_eh_frame = true;
-		}
-	    }
-
-	  if (seen_type == COMPACT_EH_HDR)
-	    link_info.eh_frame_hdr_type = COMPACT_EH_HDR;
-	}
-      if (elfbfd)
-	{
-	  const struct elf_backend_data *bed;
-
-	  bed = get_elf_backend_data (elfbfd);
-	  s = bfd_make_section_with_flags (elfbfd, ".eh_frame_hdr",
-					   bed->dynamic_sec_flags
-					   | SEC_READONLY);
-	  if (s != NULL
-	      && bfd_set_section_alignment (s, 2))
-	    {
-	      htab->eh_info.hdr_sec = s;
-	      warn_eh_frame = false;
-	    }
-	}
-      if (warn_eh_frame)
-	einfo (_("%P: warning: cannot create .eh_frame_hdr section,"
-		 " --eh-frame-hdr ignored\n"));
-    }
-
   /* Get the list of files which appear in DT_NEEDED entries in
      dynamic objects included in the link (often there will be none).
      For each such file, we want to track down the corresponding
@@ -1195,10 +1037,12 @@ ldelf_after_open (int use_libpath, int native, int is_linux, int is_freebsd,
 	  && (bfd_elf_get_dyn_lib_class (l->by) & DYN_AS_NEEDED) != 0)
 	continue;
 
-      /* Skip the lib if --no-copy-dt-needed-entries and
-	 --allow-shlib-undefined is in effect.  */
+      /* Skip the lib if --no-copy-dt-needed-entries and before calling
+         plugin 'all symbols read' hook or --allow-shlib-undefined is
+	 in effect.  */
       if (l->by != NULL
-	  && link_info.unresolved_syms_in_shared_libs == RM_IGNORE
+	  && (htab->before_plugin_all_symbols_read
+	      || link_info.unresolved_syms_in_shared_libs == RM_IGNORE)
 	  && (bfd_elf_get_dyn_lib_class (l->by) & DYN_NO_ADD_NEEDED) != 0)
 	continue;
 
@@ -1338,23 +1182,215 @@ ldelf_after_open (int use_libpath, int native, int is_linux, int is_freebsd,
 	     l->name, l->by);
     }
 
-  for (abfd = link_info.input_bfds; abfd; abfd = abfd->link.next)
-    if (bfd_get_format (abfd) == bfd_object
-	&& ((abfd->flags) & DYNAMIC) != 0
-	&& bfd_get_flavour (abfd) == bfd_target_elf_flavour
-	&& (elf_dyn_lib_class (abfd) & (DYN_AS_NEEDED | DYN_NO_NEEDED)) == 0
-	&& elf_dt_name (abfd) != NULL)
-      {
-	if (bfd_elf_add_dt_needed_tag (abfd, &link_info) < 0)
-	  einfo (_("%F%P: failed to add DT_NEEDED dynamic tag\n"));
-      }
+  /* Don't add DT_NEEDED when loading shared objects from DT_NEEDED for
+     plugin symbol resolution before calling plugin 'all symbols read'
+     hook.  */
+  if (!htab->before_plugin_all_symbols_read)
+    for (abfd = link_info.input_bfds; abfd; abfd = abfd->link.next)
+      if (bfd_get_format (abfd) == bfd_object
+	  && ((abfd->flags) & DYNAMIC) != 0
+	  && bfd_get_flavour (abfd) == bfd_target_elf_flavour
+	  && (elf_dyn_lib_class (abfd) & (DYN_AS_NEEDED | DYN_NO_NEEDED)) == 0
+	  && elf_dt_name (abfd) != NULL)
+	{
+	  if (bfd_elf_add_dt_needed_tag (abfd, &link_info) < 0)
+	    einfo (_("%F%P: failed to add DT_NEEDED dynamic tag\n"));
+	}
 
   link_info.input_bfds_tail = save_input_bfd_tail;
   *save_input_bfd_tail = NULL;
+}
+
+/* This is called before calling plugin 'all symbols read' hook.  */
+
+void
+ldelf_before_plugin_all_symbols_read (int use_libpath, int native,
+				      int is_linux, int is_freebsd,
+				      int elfsize, const char *prefix)
+{
+  struct elf_link_hash_table *htab = elf_hash_table (&link_info);
+
+  if (!is_elf_hash_table (&htab->root))
+    return;
+
+  htab->before_plugin_all_symbols_read = true;
+  ldelf_handle_dt_needed (htab, use_libpath, native, is_linux,
+			  is_freebsd, elfsize, prefix);
+  htab->before_plugin_all_symbols_read = false;
+}
+
+/* This is called after all the input files have been opened and all
+   symbols have been loaded.  */
+
+void
+ldelf_after_open (int use_libpath, int native, int is_linux, int is_freebsd,
+		  int elfsize, const char *prefix)
+{
+  struct elf_link_hash_table *htab;
+  asection *s;
+  bfd *abfd;
+
+  after_open_default ();
+
+  htab = elf_hash_table (&link_info);
+  if (!is_elf_hash_table (&htab->root))
+    return;
+
+  if (command_line.out_implib_filename)
+    {
+      unlink_if_ordinary (command_line.out_implib_filename);
+      link_info.out_implib_bfd
+	= bfd_openw (command_line.out_implib_filename,
+		     bfd_get_target (link_info.output_bfd));
+
+      if (link_info.out_implib_bfd == NULL)
+	{
+	  einfo (_("%F%P: %s: can't open for writing: %E\n"),
+		 command_line.out_implib_filename);
+	}
+    }
+
+  if (ldelf_emit_note_gnu_build_id != NULL)
+    {
+      /* Find an ELF input.  */
+      for (abfd = link_info.input_bfds;
+	   abfd != (bfd *) NULL; abfd = abfd->link.next)
+	if (bfd_get_flavour (abfd) == bfd_target_elf_flavour
+	    && bfd_count_sections (abfd) != 0
+	    && !bfd_input_just_syms (abfd))
+	  break;
+
+      /* PR 10555: If there are no ELF input files do not try to
+	 create a .note.gnu-build-id section.  */
+      if (abfd == NULL
+	  || !ldelf_setup_build_id (abfd))
+	{
+	  free ((char *) ldelf_emit_note_gnu_build_id);
+	  ldelf_emit_note_gnu_build_id = NULL;
+	}
+    }
+
+  get_elf_backend_data (link_info.output_bfd)->setup_gnu_properties (&link_info);
+
+  /* Do not allow executable files to be used as inputs to the link.  */
+  for (abfd = link_info.input_bfds; abfd; abfd = abfd->link.next)
+    {
+      /* Discard input .note.gnu.build-id sections.  */
+      s = bfd_get_section_by_name (abfd, ".note.gnu.build-id");
+      while (s != NULL)
+	{
+	  if (s != elf_tdata (link_info.output_bfd)->o->build_id.sec)
+	    s->flags |= SEC_EXCLUDE;
+	  s = bfd_get_next_section_by_name (NULL, s);
+	}
+
+      if (abfd->xvec->flavour == bfd_target_elf_flavour
+	  && !bfd_input_just_syms (abfd)
+	  && elf_tdata (abfd) != NULL
+	  /* FIXME: Maybe check for other non-supportable types as well ?  */
+	  && (elf_tdata (abfd)->elf_header->e_type == ET_EXEC
+	      || (elf_tdata (abfd)->elf_header->e_type == ET_DYN
+		  && elf_tdata (abfd)->is_pie)))
+	einfo (_("%F%P: cannot use executable file '%pB' as input to a link\n"),
+	       abfd);
+    }
+
+  if (bfd_link_relocatable (&link_info))
+    {
+      if (link_info.execstack == !link_info.noexecstack)
+	{
+	  /* PR ld/16744: If "-z [no]execstack" has been specified on the
+	     command line and we are perfoming a relocatable link then no
+	     PT_GNU_STACK segment will be created and so the
+	     linkinfo.[no]execstack values set in _handle_option() will have no
+	     effect.  Instead we create a .note.GNU-stack section in much the
+	     same way as the assembler does with its --[no]execstack option.  */
+	  flagword flags = SEC_READONLY | (link_info.execstack ? SEC_CODE : 0);
+	  (void) bfd_make_section_with_flags (link_info.input_bfds,
+					      ".note.GNU-stack", flags);
+	}
+      return;
+    }
+
+  if (!link_info.traditional_format)
+    {
+      bfd *elfbfd = NULL;
+      bool warn_eh_frame = false;
+      int seen_type = 0;
+
+      for (abfd = link_info.input_bfds; abfd; abfd = abfd->link.next)
+	{
+	  int type = 0;
+
+	  if (bfd_input_just_syms (abfd))
+	    continue;
+
+	  for (s = abfd->sections; s && type < COMPACT_EH_HDR; s = s->next)
+	    {
+	      const char *name = bfd_section_name (s);
+
+	      if (bfd_is_abs_section (s->output_section))
+		continue;
+	      if (startswith (name, ".eh_frame_entry"))
+		type = COMPACT_EH_HDR;
+	      else if (strcmp (name, ".eh_frame") == 0 && s->size > 8)
+		type = DWARF2_EH_HDR;
+	    }
+
+	  if (type != 0)
+	    {
+	      if (seen_type == 0)
+		{
+		  seen_type = type;
+		}
+	      else if (seen_type != type)
+		{
+		  einfo (_("%F%P: compact frame descriptions incompatible with"
+			   " DWARF2 .eh_frame from %pB\n"),
+			 type == DWARF2_EH_HDR ? abfd : elfbfd);
+		  break;
+		}
+
+	      if (!elfbfd
+		  && (type == COMPACT_EH_HDR
+		      || link_info.eh_frame_hdr_type != 0))
+		{
+		  if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
+		    elfbfd = abfd;
+
+		  warn_eh_frame = true;
+		}
+	    }
+
+	  if (seen_type == COMPACT_EH_HDR)
+	    link_info.eh_frame_hdr_type = COMPACT_EH_HDR;
+	}
+      if (elfbfd)
+	{
+	  const struct elf_backend_data *bed;
+
+	  bed = get_elf_backend_data (elfbfd);
+	  s = bfd_make_section_with_flags (elfbfd, ".eh_frame_hdr",
+					   bed->dynamic_sec_flags
+					   | SEC_READONLY);
+	  if (s != NULL
+	      && bfd_set_section_alignment (s, 2))
+	    {
+	      htab->eh_info.hdr_sec = s;
+	      warn_eh_frame = false;
+	    }
+	}
+      if (warn_eh_frame)
+	einfo (_("%P: warning: cannot create .eh_frame_hdr section,"
+		 " --eh-frame-hdr ignored\n"));
+    }
 
   if (link_info.eh_frame_hdr_type == COMPACT_EH_HDR)
     if (!bfd_elf_parse_eh_frame_entries (NULL, &link_info))
       einfo (_("%F%P: failed to parse EH frame entries\n"));
+
+  ldelf_handle_dt_needed (htab, use_libpath, native, is_linux,
+			  is_freebsd, elfsize, prefix);
 }
 
 static bfd_size_type
diff --git a/ld/ldelf.h b/ld/ldelf.h
index 0da26c9ea76..efa8b45851c 100644
--- a/ld/ldelf.h
+++ b/ld/ldelf.h
@@ -22,6 +22,8 @@ extern const char *ldelf_emit_note_gnu_build_id;
 
 extern void ldelf_after_parse (void);
 extern bool ldelf_load_symbols (lang_input_statement_type *);
+extern void ldelf_before_plugin_all_symbols_read (int, int, int, int,
+						  int, const char *);
 extern void ldelf_after_open (int, int, int, int, int, const char *);
 extern bool ldelf_setup_build_id (bfd *);
 extern void ldelf_append_to_separated_string (char **, char *);
diff --git a/ld/ldemul.c b/ld/ldemul.c
index 85c00ded75e..4c8cad81f98 100644
--- a/ld/ldemul.c
+++ b/ld/ldemul.c
@@ -59,6 +59,13 @@ ldemul_before_parse (void)
   ld_emulation->before_parse ();
 }
 
+void
+ldemul_before_plugin_all_symbols_read (void)
+{
+  if (ld_emulation->before_plugin_all_symbols_read)
+    ld_emulation->before_plugin_all_symbols_read ();
+}
+
 void
 ldemul_after_open (void)
 {
diff --git a/ld/ldemul.h b/ld/ldemul.h
index 33e690d78ac..16a3b6991bd 100644
--- a/ld/ldemul.h
+++ b/ld/ldemul.h
@@ -32,6 +32,8 @@ extern void ldemul_after_parse
   (void);
 extern void ldemul_before_parse
   (void);
+extern void ldemul_before_plugin_all_symbols_read
+  (void);
 extern void ldemul_after_open
   (void);
 extern void ldemul_after_check_relocs
@@ -131,6 +133,9 @@ typedef struct ld_emulation_xfer_struct {
   /* Run after parsing the command line and script file.  */
   void   (*after_parse) (void);
 
+  /* Run before calling plugin 'all symbols read' hook.  */
+  void   (*before_plugin_all_symbols_read)  (void);
+
   /* Run after opening all input files, and loading the symbols.  */
   void   (*after_open) (void);
 
diff --git a/ld/ldlang.c b/ld/ldlang.c
index 1733f8e65c4..1c8d229326c 100644
--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -8080,6 +8080,8 @@ lang_process (void)
       lang_statement_list_type added;
       lang_statement_list_type files, inputfiles;
 
+      ldemul_before_plugin_all_symbols_read ();
+
       /* Now all files are read, let the plugin(s) decide if there
 	 are any more to be added to the link before we call the
 	 emulation's after_open hook.  We create a private list of
diff --git a/ld/testsuite/ld-plugin/lto.exp b/ld/testsuite/ld-plugin/lto.exp
index 64b880265ee..f4ea1d48533 100644
--- a/ld/testsuite/ld-plugin/lto.exp
+++ b/ld/testsuite/ld-plugin/lto.exp
@@ -497,6 +497,31 @@ set lto_link_elf_tests [list \
    "pr28879" \
    "c++" \
   ] \
+  [list \
+   "Build libpr28849a.so" \
+   "-shared" \
+   "-fPIC" \
+   {pr28849a.c} \
+   "" \
+   "libpr28849a.so" \
+  ] \
+  [list \
+   "Build libpr28849b.so" \
+   "-shared -Wl,--no-as-needed,tmpdir/libpr28849a.so" \
+   "" \
+   {dummy.c} \
+   "" \
+   "libpr28849b.so" \
+  ] \
+  [list \
+   "Build pr28849" \
+   "-Wl,--no-as-needed,--copy-dt-needed-entries,-rpath-link,. \
+    tmpdir/libpr28849b.so" \
+   "-O2 -flto" \
+   {pr28849b.c} \
+   {{"nm" {-D} "pr28849.d"}} \
+   "pr28849" \
+  ] \
 ]
 
 # PR 14918 checks that libgcc is not spuriously included in a shared link of
diff --git a/ld/testsuite/ld-plugin/pr28849.d b/ld/testsuite/ld-plugin/pr28849.d
new file mode 100644
index 00000000000..a1f90c1ac8c
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr28849.d
@@ -0,0 +1,3 @@
+#...
+[0-9a-f]+ T _?should_be_dynamic_in_exec
+#pass
diff --git a/ld/testsuite/ld-plugin/pr28849a.c b/ld/testsuite/ld-plugin/pr28849a.c
new file mode 100644
index 00000000000..2fc5c7b052b
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr28849a.c
@@ -0,0 +1,2 @@
+extern void should_be_dynamic_in_exec (void);
+void y (void) { should_be_dynamic_in_exec (); }
diff --git a/ld/testsuite/ld-plugin/pr28849b.c b/ld/testsuite/ld-plugin/pr28849b.c
new file mode 100644
index 00000000000..616d9a585d2
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr28849b.c
@@ -0,0 +1,3 @@
+extern void y (void);
+void should_be_dynamic_in_exec (void) {}
+int main (void) { y (); return 0; }
-- 
2.35.1

Re: [PATCH] ld: Add a before_plugin_all_symbols_read hook

[Alan Modra]

On Tue, Mar 08, 2022 at 09:22:30AM -0800, H.J. Lu via Binutils wrote:
> Add a before_plugin_all_symbols_read hook to load symbol references from
> DT_NEEDED entries, included from --copy-dt-needed-entries, before reading
> plugin symbols to properly resolve plugin symbol references.

OK, except

> 	* elf-bfd.h (elf_link_hash_table): Add
> 	before_plugin_all_symbols_read.

please change the name of this flag to better reflect what it does.
"handling_dt_needed" perhaps.  You set and clear the flag around the
new ldelf_handle_dt_needed function.  It isn't set before
plugin_call_all_symbols_read and clear afterwards.

-- 
Alan Modra
Australia Development Lab, IBM

Re: [PATCH] ld: Add a before_plugin_all_symbols_read hook

[H.J. Lu]

[-- Attachment #1: Type: text/plain, Size: 849 bytes --]

On Wed, Mar 9, 2022 at 5:20 PM Alan Modra <amodra@gmail.com> wrote:
>
> On Tue, Mar 08, 2022 at 09:22:30AM -0800, H.J. Lu via Binutils wrote:
> > Add a before_plugin_all_symbols_read hook to load symbol references from
> > DT_NEEDED entries, included from --copy-dt-needed-entries, before reading
> > plugin symbols to properly resolve plugin symbol references.
>
> OK, except
>
> >       * elf-bfd.h (elf_link_hash_table): Add
> >       before_plugin_all_symbols_read.
>
> please change the name of this flag to better reflect what it does.
> "handling_dt_needed" perhaps.  You set and clear the flag around the

Done.   This is the v2 patch I am checking in.

Thanks.

> new ldelf_handle_dt_needed function.  It isn't set before
> plugin_call_all_symbols_read and clear afterwards.
>
> --
> Alan Modra
> Australia Development Lab, IBM



-- 
H.J.

[-- Attachment #2: v2-0001-ld-Add-a-before_plugin_all_symbols_read-hook.patch --]
[-- Type: text/x-patch, Size: 23195 bytes --]

From 2bfd5689a2a39672930e557c601c9ed798333ee9 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Wed, 2 Feb 2022 14:40:03 -0800
Subject: [PATCH v2] ld: Add a before_plugin_all_symbols_read hook

Add a before_plugin_all_symbols_read hook to load symbol references from
DT_NEEDED entries, included from --copy-dt-needed-entries, before reading
plugin symbols to properly resolve plugin symbol references.

bfd/

	PR ld/28849
	* elf-bfd.h (elf_link_hash_table): Add handling_dt_needed.
	* elflink.c (_bfd_elf_merge_symbol): Don't set non_ir_ref_dynamic
	before plugin 'all symbols read' hook is called.

ld/

	PR ld/28849
	* ldelf.c (ldelf_handle_dt_needed): New function.
	(ldelf_before_plugin_all_symbols_read): Likewise.
	(ldelf_after_open): Call ldelf_handle_dt_needed.
	* ldelf.h (ldelf_before_plugin_all_symbols_read): New.
	* ldemul.c (ldemul_before_plugin_all_symbols_read): Likewise.
	* ldemul.h (ldemul_before_plugin_all_symbols_read): Likewise.
	(ld_emulation_xfer_struct): Add before_plugin_all_symbols_read.
	* ldlang.c (lang_process): Call
	ldemul_before_plugin_all_symbols_read before calling
	plugin_call_all_symbols_read.
	* emultempl/elf.em
	(gld${EMULATION_NAME}_before_plugin_all_symbols_read): New.
	(LDEMUL_BEFORE_PLUGIN_ALL_SYMBOLS_READ): New.
	* emultempl/emulation.em (ld_${EMULATION_NAME}_emulation):
	Initialize the before_plugin_all_symbols_read field.
	* testsuite/ld-plugin/lto.exp: Run PR ld/28849 tests.
	* testsuite/ld-plugin/pr28849.d: New file.
	* testsuite/ld-plugin/pr28849a.c: Likewise.
	* testsuite/ld-plugin/pr28849b.c: Likewise.
---
 bfd/elf-bfd.h                     |   3 +
 bfd/elflink.c                     |   7 +-
 ld/emultempl/elf.em               |  14 ++
 ld/emultempl/emulation.em         |   1 +
 ld/ldelf.c                        | 385 ++++++++++++++++--------------
 ld/ldelf.h                        |   2 +
 ld/ldemul.c                       |   7 +
 ld/ldemul.h                       |   5 +
 ld/ldlang.c                       |   2 +
 ld/testsuite/ld-plugin/lto.exp    |  25 ++
 ld/testsuite/ld-plugin/pr28849.d  |   3 +
 ld/testsuite/ld-plugin/pr28849a.c |   2 +
 ld/testsuite/ld-plugin/pr28849b.c |   3 +
 13 files changed, 283 insertions(+), 176 deletions(-)
 create mode 100644 ld/testsuite/ld-plugin/pr28849.d
 create mode 100644 ld/testsuite/ld-plugin/pr28849a.c
 create mode 100644 ld/testsuite/ld-plugin/pr28849b.c

diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
index 889a4746371..4904e1e0aa9 100644
--- a/bfd/elf-bfd.h
+++ b/bfd/elf-bfd.h
@@ -599,6 +599,9 @@ struct elf_link_hash_table
   /* TRUE if DT_JMPREL is a required dynamic tag.  */
   bool dt_jmprel_required;
 
+  /* TRUE when we are handling DT_NEEDED entries.  */
+  bool handling_dt_needed;
+
   /* The BFD used to hold special sections created by the linker.
      This will be the first BFD found which requires these sections to
      be created.  */
diff --git a/bfd/elflink.c b/bfd/elflink.c
index f8521426cad..5a070a26e35 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -1090,6 +1090,7 @@ _bfd_elf_merge_symbol (bfd *abfd,
   const struct elf_backend_data *bed;
   char *new_version;
   bool default_sym = *matched;
+  struct elf_link_hash_table *htab;
 
   *skip = false;
   *override = NULL;
@@ -1220,6 +1221,8 @@ _bfd_elf_merge_symbol (bfd *abfd,
      symbols.  */
   bfd_elf_link_mark_dynamic_symbol (info, h, sym);
 
+  htab = elf_hash_table (info);
+
   /* NEWDYN and OLDDYN indicate whether the new or old symbol,
      respectively, is from a dynamic object.  */
 
@@ -1283,7 +1286,9 @@ _bfd_elf_merge_symbol (bfd *abfd,
       olddyn = (oldsec->symbol->flags & BSF_DYNAMIC) != 0;
     }
 
-  if (oldbfd != NULL
+  /* Set non_ir_ref_dynamic only when not handling DT_NEEDED entries.  */
+  if (!htab->handling_dt_needed
+      && oldbfd != NULL
       && (oldbfd->flags & BFD_PLUGIN) != (abfd->flags & BFD_PLUGIN))
     {
       if (newdyn != olddyn)
diff --git a/ld/emultempl/elf.em b/ld/emultempl/elf.em
index 55dd20f0b02..7ae6f6d50e1 100644
--- a/ld/emultempl/elf.em
+++ b/ld/emultempl/elf.em
@@ -53,6 +53,8 @@ fragment <<EOF
 
 /* Declare functions used by various EXTRA_EM_FILEs.  */
 static void gld${EMULATION_NAME}_before_parse (void);
+static void gld${EMULATION_NAME}_before_plugin_all_symbols_read
+  (void);
 static void gld${EMULATION_NAME}_after_open (void);
 static void gld${EMULATION_NAME}_before_allocation (void);
 static void gld${EMULATION_NAME}_after_allocation (void);
@@ -125,6 +127,17 @@ if test x"$LDEMUL_AFTER_OPEN" != xgld"$EMULATION_NAME"_after_open; then
 
 fragment <<EOF
 
+/* This is called before calling plugin 'all symbols read' hook.  */
+
+static void
+gld${EMULATION_NAME}_before_plugin_all_symbols_read (void)
+{
+  ldelf_before_plugin_all_symbols_read ($IS_LIBPATH, $IS_NATIVE,
+				        $IS_LINUX_TARGET,
+					$IS_FREEBSD_TARGET,
+					$ELFSIZE, "$prefix");
+}
+
 /* This is called after all the input files have been opened.  */
 
 static void
@@ -910,6 +923,7 @@ fi
 fi
 
 LDEMUL_AFTER_PARSE=${LDEMUL_AFTER_PARSE-ldelf_after_parse}
+LDEMUL_BEFORE_PLUGIN_ALL_SYMBOLS_READ=${LDEMUL_BEFORE_PLUGIN_ALL_SYMBOLS_READ-gld${EMULATION_NAME}_before_plugin_all_symbols_read}
 LDEMUL_AFTER_OPEN=${LDEMUL_AFTER_OPEN-gld${EMULATION_NAME}_after_open}
 LDEMUL_BEFORE_PLACE_ORPHANS=${LDEMUL_BEFORE_PLACE_ORPHANS-ldelf_before_place_orphans}
 LDEMUL_AFTER_ALLOCATION=${LDEMUL_AFTER_ALLOCATION-gld${EMULATION_NAME}_after_allocation}
diff --git a/ld/emultempl/emulation.em b/ld/emultempl/emulation.em
index cfa6567ac2b..7fe821a519d 100644
--- a/ld/emultempl/emulation.em
+++ b/ld/emultempl/emulation.em
@@ -8,6 +8,7 @@ struct ld_emulation_xfer_struct ld_${EMULATION_NAME}_emulation =
   ${LDEMUL_SYSLIB-syslib_default},
   ${LDEMUL_HLL-hll_default},
   ${LDEMUL_AFTER_PARSE-after_parse_default},
+  ${LDEMUL_BEFORE_PLUGIN_ALL_SYMBOLS_READ-NULL},
   ${LDEMUL_AFTER_OPEN-after_open_default},
   ${LDEMUL_AFTER_CHECK_RELOCS-after_check_relocs_default},
   ${LDEMUL_BEFORE_PLACE_ORPHANS-before_place_orphans_default},
diff --git a/ld/ldelf.c b/ld/ldelf.c
index 33c6a9f1f46..4094640b3f7 100644
--- a/ld/ldelf.c
+++ b/ld/ldelf.c
@@ -1005,173 +1005,15 @@ ldelf_check_needed (lang_input_statement_type *s)
     }
 }
 
-/* This is called after all the input files have been opened.  */
-
-void
-ldelf_after_open (int use_libpath, int native, int is_linux, int is_freebsd,
-		  int elfsize, const char *prefix)
+static void
+ldelf_handle_dt_needed (struct elf_link_hash_table *htab,
+			int use_libpath, int native, int is_linux,
+			int is_freebsd, int elfsize, const char *prefix)
 {
   struct bfd_link_needed_list *needed, *l;
-  struct elf_link_hash_table *htab;
-  asection *s;
   bfd *abfd;
   bfd **save_input_bfd_tail;
 
-  after_open_default ();
-
-  htab = elf_hash_table (&link_info);
-  if (!is_elf_hash_table (&htab->root))
-    return;
-
-  if (command_line.out_implib_filename)
-    {
-      unlink_if_ordinary (command_line.out_implib_filename);
-      link_info.out_implib_bfd
-	= bfd_openw (command_line.out_implib_filename,
-		     bfd_get_target (link_info.output_bfd));
-
-      if (link_info.out_implib_bfd == NULL)
-	{
-	  einfo (_("%F%P: %s: can't open for writing: %E\n"),
-		 command_line.out_implib_filename);
-	}
-    }
-
-  if (ldelf_emit_note_gnu_build_id != NULL)
-    {
-      /* Find an ELF input.  */
-      for (abfd = link_info.input_bfds;
-	   abfd != (bfd *) NULL; abfd = abfd->link.next)
-	if (bfd_get_flavour (abfd) == bfd_target_elf_flavour
-	    && bfd_count_sections (abfd) != 0
-	    && !bfd_input_just_syms (abfd))
-	  break;
-
-      /* PR 10555: If there are no ELF input files do not try to
-	 create a .note.gnu-build-id section.  */
-      if (abfd == NULL
-	  || !ldelf_setup_build_id (abfd))
-	{
-	  free ((char *) ldelf_emit_note_gnu_build_id);
-	  ldelf_emit_note_gnu_build_id = NULL;
-	}
-    }
-
-  get_elf_backend_data (link_info.output_bfd)->setup_gnu_properties (&link_info);
-
-  /* Do not allow executable files to be used as inputs to the link.  */
-  for (abfd = link_info.input_bfds; abfd; abfd = abfd->link.next)
-    {
-      /* Discard input .note.gnu.build-id sections.  */
-      s = bfd_get_section_by_name (abfd, ".note.gnu.build-id");
-      while (s != NULL)
-	{
-	  if (s != elf_tdata (link_info.output_bfd)->o->build_id.sec)
-	    s->flags |= SEC_EXCLUDE;
-	  s = bfd_get_next_section_by_name (NULL, s);
-	}
-
-      if (abfd->xvec->flavour == bfd_target_elf_flavour
-	  && !bfd_input_just_syms (abfd)
-	  && elf_tdata (abfd) != NULL
-	  /* FIXME: Maybe check for other non-supportable types as well ?  */
-	  && (elf_tdata (abfd)->elf_header->e_type == ET_EXEC
-	      || (elf_tdata (abfd)->elf_header->e_type == ET_DYN
-		  && elf_tdata (abfd)->is_pie)))
-	einfo (_("%F%P: cannot use executable file '%pB' as input to a link\n"),
-	       abfd);
-    }
-
-  if (bfd_link_relocatable (&link_info))
-    {
-      if (link_info.execstack == !link_info.noexecstack)
-	{
-	  /* PR ld/16744: If "-z [no]execstack" has been specified on the
-	     command line and we are perfoming a relocatable link then no
-	     PT_GNU_STACK segment will be created and so the
-	     linkinfo.[no]execstack values set in _handle_option() will have no
-	     effect.  Instead we create a .note.GNU-stack section in much the
-	     same way as the assembler does with its --[no]execstack option.  */
-	  flagword flags = SEC_READONLY | (link_info.execstack ? SEC_CODE : 0);
-	  (void) bfd_make_section_with_flags (link_info.input_bfds,
-					      ".note.GNU-stack", flags);
-	}
-      return;
-    }
-
-  if (!link_info.traditional_format)
-    {
-      bfd *elfbfd = NULL;
-      bool warn_eh_frame = false;
-      int seen_type = 0;
-
-      for (abfd = link_info.input_bfds; abfd; abfd = abfd->link.next)
-	{
-	  int type = 0;
-
-	  if (bfd_input_just_syms (abfd))
-	    continue;
-
-	  for (s = abfd->sections; s && type < COMPACT_EH_HDR; s = s->next)
-	    {
-	      const char *name = bfd_section_name (s);
-
-	      if (bfd_is_abs_section (s->output_section))
-		continue;
-	      if (startswith (name, ".eh_frame_entry"))
-		type = COMPACT_EH_HDR;
-	      else if (strcmp (name, ".eh_frame") == 0 && s->size > 8)
-		type = DWARF2_EH_HDR;
-	    }
-
-	  if (type != 0)
-	    {
-	      if (seen_type == 0)
-		{
-		  seen_type = type;
-		}
-	      else if (seen_type != type)
-		{
-		  einfo (_("%F%P: compact frame descriptions incompatible with"
-			   " DWARF2 .eh_frame from %pB\n"),
-			 type == DWARF2_EH_HDR ? abfd : elfbfd);
-		  break;
-		}
-
-	      if (!elfbfd
-		  && (type == COMPACT_EH_HDR
-		      || link_info.eh_frame_hdr_type != 0))
-		{
-		  if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
-		    elfbfd = abfd;
-
-		  warn_eh_frame = true;
-		}
-	    }
-
-	  if (seen_type == COMPACT_EH_HDR)
-	    link_info.eh_frame_hdr_type = COMPACT_EH_HDR;
-	}
-      if (elfbfd)
-	{
-	  const struct elf_backend_data *bed;
-
-	  bed = get_elf_backend_data (elfbfd);
-	  s = bfd_make_section_with_flags (elfbfd, ".eh_frame_hdr",
-					   bed->dynamic_sec_flags
-					   | SEC_READONLY);
-	  if (s != NULL
-	      && bfd_set_section_alignment (s, 2))
-	    {
-	      htab->eh_info.hdr_sec = s;
-	      warn_eh_frame = false;
-	    }
-	}
-      if (warn_eh_frame)
-	einfo (_("%P: warning: cannot create .eh_frame_hdr section,"
-		 " --eh-frame-hdr ignored\n"));
-    }
-
   /* Get the list of files which appear in DT_NEEDED entries in
      dynamic objects included in the link (often there will be none).
      For each such file, we want to track down the corresponding
@@ -1195,10 +1037,12 @@ ldelf_after_open (int use_libpath, int native, int is_linux, int is_freebsd,
 	  && (bfd_elf_get_dyn_lib_class (l->by) & DYN_AS_NEEDED) != 0)
 	continue;
 
-      /* Skip the lib if --no-copy-dt-needed-entries and
-	 --allow-shlib-undefined is in effect.  */
+      /* Skip the lib if --no-copy-dt-needed-entries and when we are
+	 handling DT_NEEDED entries or --allow-shlib-undefined is in
+	 effect.  */
       if (l->by != NULL
-	  && link_info.unresolved_syms_in_shared_libs == RM_IGNORE
+	  && (htab->handling_dt_needed
+	      || link_info.unresolved_syms_in_shared_libs == RM_IGNORE)
 	  && (bfd_elf_get_dyn_lib_class (l->by) & DYN_NO_ADD_NEEDED) != 0)
 	continue;
 
@@ -1338,23 +1182,214 @@ ldelf_after_open (int use_libpath, int native, int is_linux, int is_freebsd,
 	     l->name, l->by);
     }
 
-  for (abfd = link_info.input_bfds; abfd; abfd = abfd->link.next)
-    if (bfd_get_format (abfd) == bfd_object
-	&& ((abfd->flags) & DYNAMIC) != 0
-	&& bfd_get_flavour (abfd) == bfd_target_elf_flavour
-	&& (elf_dyn_lib_class (abfd) & (DYN_AS_NEEDED | DYN_NO_NEEDED)) == 0
-	&& elf_dt_name (abfd) != NULL)
-      {
-	if (bfd_elf_add_dt_needed_tag (abfd, &link_info) < 0)
-	  einfo (_("%F%P: failed to add DT_NEEDED dynamic tag\n"));
-      }
+  /* Don't add DT_NEEDED when loading shared objects from DT_NEEDED for
+     plugin symbol resolution while handling DT_NEEDED entries.  */
+  if (!htab->handling_dt_needed)
+    for (abfd = link_info.input_bfds; abfd; abfd = abfd->link.next)
+      if (bfd_get_format (abfd) == bfd_object
+	  && ((abfd->flags) & DYNAMIC) != 0
+	  && bfd_get_flavour (abfd) == bfd_target_elf_flavour
+	  && (elf_dyn_lib_class (abfd) & (DYN_AS_NEEDED | DYN_NO_NEEDED)) == 0
+	  && elf_dt_name (abfd) != NULL)
+	{
+	  if (bfd_elf_add_dt_needed_tag (abfd, &link_info) < 0)
+	    einfo (_("%F%P: failed to add DT_NEEDED dynamic tag\n"));
+	}
 
   link_info.input_bfds_tail = save_input_bfd_tail;
   *save_input_bfd_tail = NULL;
+}
+
+/* This is called before calling plugin 'all symbols read' hook.  */
+
+void
+ldelf_before_plugin_all_symbols_read (int use_libpath, int native,
+				      int is_linux, int is_freebsd,
+				      int elfsize, const char *prefix)
+{
+  struct elf_link_hash_table *htab = elf_hash_table (&link_info);
+
+  if (!is_elf_hash_table (&htab->root))
+    return;
+
+  htab->handling_dt_needed = true;
+  ldelf_handle_dt_needed (htab, use_libpath, native, is_linux,
+			  is_freebsd, elfsize, prefix);
+  htab->handling_dt_needed = false;
+}
+
+/* This is called after all the input files have been opened and all
+   symbols have been loaded.  */
+
+void
+ldelf_after_open (int use_libpath, int native, int is_linux, int is_freebsd,
+		  int elfsize, const char *prefix)
+{
+  struct elf_link_hash_table *htab;
+  asection *s;
+  bfd *abfd;
+
+  after_open_default ();
+
+  htab = elf_hash_table (&link_info);
+  if (!is_elf_hash_table (&htab->root))
+    return;
+
+  if (command_line.out_implib_filename)
+    {
+      unlink_if_ordinary (command_line.out_implib_filename);
+      link_info.out_implib_bfd
+	= bfd_openw (command_line.out_implib_filename,
+		     bfd_get_target (link_info.output_bfd));
+
+      if (link_info.out_implib_bfd == NULL)
+	{
+	  einfo (_("%F%P: %s: can't open for writing: %E\n"),
+		 command_line.out_implib_filename);
+	}
+    }
+
+  if (ldelf_emit_note_gnu_build_id != NULL)
+    {
+      /* Find an ELF input.  */
+      for (abfd = link_info.input_bfds;
+	   abfd != (bfd *) NULL; abfd = abfd->link.next)
+	if (bfd_get_flavour (abfd) == bfd_target_elf_flavour
+	    && bfd_count_sections (abfd) != 0
+	    && !bfd_input_just_syms (abfd))
+	  break;
+
+      /* PR 10555: If there are no ELF input files do not try to
+	 create a .note.gnu-build-id section.  */
+      if (abfd == NULL
+	  || !ldelf_setup_build_id (abfd))
+	{
+	  free ((char *) ldelf_emit_note_gnu_build_id);
+	  ldelf_emit_note_gnu_build_id = NULL;
+	}
+    }
+
+  get_elf_backend_data (link_info.output_bfd)->setup_gnu_properties (&link_info);
+
+  /* Do not allow executable files to be used as inputs to the link.  */
+  for (abfd = link_info.input_bfds; abfd; abfd = abfd->link.next)
+    {
+      /* Discard input .note.gnu.build-id sections.  */
+      s = bfd_get_section_by_name (abfd, ".note.gnu.build-id");
+      while (s != NULL)
+	{
+	  if (s != elf_tdata (link_info.output_bfd)->o->build_id.sec)
+	    s->flags |= SEC_EXCLUDE;
+	  s = bfd_get_next_section_by_name (NULL, s);
+	}
+
+      if (abfd->xvec->flavour == bfd_target_elf_flavour
+	  && !bfd_input_just_syms (abfd)
+	  && elf_tdata (abfd) != NULL
+	  /* FIXME: Maybe check for other non-supportable types as well ?  */
+	  && (elf_tdata (abfd)->elf_header->e_type == ET_EXEC
+	      || (elf_tdata (abfd)->elf_header->e_type == ET_DYN
+		  && elf_tdata (abfd)->is_pie)))
+	einfo (_("%F%P: cannot use executable file '%pB' as input to a link\n"),
+	       abfd);
+    }
+
+  if (bfd_link_relocatable (&link_info))
+    {
+      if (link_info.execstack == !link_info.noexecstack)
+	{
+	  /* PR ld/16744: If "-z [no]execstack" has been specified on the
+	     command line and we are perfoming a relocatable link then no
+	     PT_GNU_STACK segment will be created and so the
+	     linkinfo.[no]execstack values set in _handle_option() will have no
+	     effect.  Instead we create a .note.GNU-stack section in much the
+	     same way as the assembler does with its --[no]execstack option.  */
+	  flagword flags = SEC_READONLY | (link_info.execstack ? SEC_CODE : 0);
+	  (void) bfd_make_section_with_flags (link_info.input_bfds,
+					      ".note.GNU-stack", flags);
+	}
+      return;
+    }
+
+  if (!link_info.traditional_format)
+    {
+      bfd *elfbfd = NULL;
+      bool warn_eh_frame = false;
+      int seen_type = 0;
+
+      for (abfd = link_info.input_bfds; abfd; abfd = abfd->link.next)
+	{
+	  int type = 0;
+
+	  if (bfd_input_just_syms (abfd))
+	    continue;
+
+	  for (s = abfd->sections; s && type < COMPACT_EH_HDR; s = s->next)
+	    {
+	      const char *name = bfd_section_name (s);
+
+	      if (bfd_is_abs_section (s->output_section))
+		continue;
+	      if (startswith (name, ".eh_frame_entry"))
+		type = COMPACT_EH_HDR;
+	      else if (strcmp (name, ".eh_frame") == 0 && s->size > 8)
+		type = DWARF2_EH_HDR;
+	    }
+
+	  if (type != 0)
+	    {
+	      if (seen_type == 0)
+		{
+		  seen_type = type;
+		}
+	      else if (seen_type != type)
+		{
+		  einfo (_("%F%P: compact frame descriptions incompatible with"
+			   " DWARF2 .eh_frame from %pB\n"),
+			 type == DWARF2_EH_HDR ? abfd : elfbfd);
+		  break;
+		}
+
+	      if (!elfbfd
+		  && (type == COMPACT_EH_HDR
+		      || link_info.eh_frame_hdr_type != 0))
+		{
+		  if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
+		    elfbfd = abfd;
+
+		  warn_eh_frame = true;
+		}
+	    }
+
+	  if (seen_type == COMPACT_EH_HDR)
+	    link_info.eh_frame_hdr_type = COMPACT_EH_HDR;
+	}
+      if (elfbfd)
+	{
+	  const struct elf_backend_data *bed;
+
+	  bed = get_elf_backend_data (elfbfd);
+	  s = bfd_make_section_with_flags (elfbfd, ".eh_frame_hdr",
+					   bed->dynamic_sec_flags
+					   | SEC_READONLY);
+	  if (s != NULL
+	      && bfd_set_section_alignment (s, 2))
+	    {
+	      htab->eh_info.hdr_sec = s;
+	      warn_eh_frame = false;
+	    }
+	}
+      if (warn_eh_frame)
+	einfo (_("%P: warning: cannot create .eh_frame_hdr section,"
+		 " --eh-frame-hdr ignored\n"));
+    }
 
   if (link_info.eh_frame_hdr_type == COMPACT_EH_HDR)
     if (!bfd_elf_parse_eh_frame_entries (NULL, &link_info))
       einfo (_("%F%P: failed to parse EH frame entries\n"));
+
+  ldelf_handle_dt_needed (htab, use_libpath, native, is_linux,
+			  is_freebsd, elfsize, prefix);
 }
 
 static bfd_size_type
diff --git a/ld/ldelf.h b/ld/ldelf.h
index 0da26c9ea76..efa8b45851c 100644
--- a/ld/ldelf.h
+++ b/ld/ldelf.h
@@ -22,6 +22,8 @@ extern const char *ldelf_emit_note_gnu_build_id;
 
 extern void ldelf_after_parse (void);
 extern bool ldelf_load_symbols (lang_input_statement_type *);
+extern void ldelf_before_plugin_all_symbols_read (int, int, int, int,
+						  int, const char *);
 extern void ldelf_after_open (int, int, int, int, int, const char *);
 extern bool ldelf_setup_build_id (bfd *);
 extern void ldelf_append_to_separated_string (char **, char *);
diff --git a/ld/ldemul.c b/ld/ldemul.c
index 85c00ded75e..4c8cad81f98 100644
--- a/ld/ldemul.c
+++ b/ld/ldemul.c
@@ -59,6 +59,13 @@ ldemul_before_parse (void)
   ld_emulation->before_parse ();
 }
 
+void
+ldemul_before_plugin_all_symbols_read (void)
+{
+  if (ld_emulation->before_plugin_all_symbols_read)
+    ld_emulation->before_plugin_all_symbols_read ();
+}
+
 void
 ldemul_after_open (void)
 {
diff --git a/ld/ldemul.h b/ld/ldemul.h
index 33e690d78ac..16a3b6991bd 100644
--- a/ld/ldemul.h
+++ b/ld/ldemul.h
@@ -32,6 +32,8 @@ extern void ldemul_after_parse
   (void);
 extern void ldemul_before_parse
   (void);
+extern void ldemul_before_plugin_all_symbols_read
+  (void);
 extern void ldemul_after_open
   (void);
 extern void ldemul_after_check_relocs
@@ -131,6 +133,9 @@ typedef struct ld_emulation_xfer_struct {
   /* Run after parsing the command line and script file.  */
   void   (*after_parse) (void);
 
+  /* Run before calling plugin 'all symbols read' hook.  */
+  void   (*before_plugin_all_symbols_read)  (void);
+
   /* Run after opening all input files, and loading the symbols.  */
   void   (*after_open) (void);
 
diff --git a/ld/ldlang.c b/ld/ldlang.c
index 1733f8e65c4..1c8d229326c 100644
--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -8080,6 +8080,8 @@ lang_process (void)
       lang_statement_list_type added;
       lang_statement_list_type files, inputfiles;
 
+      ldemul_before_plugin_all_symbols_read ();
+
       /* Now all files are read, let the plugin(s) decide if there
 	 are any more to be added to the link before we call the
 	 emulation's after_open hook.  We create a private list of
diff --git a/ld/testsuite/ld-plugin/lto.exp b/ld/testsuite/ld-plugin/lto.exp
index 64b880265ee..f4ea1d48533 100644
--- a/ld/testsuite/ld-plugin/lto.exp
+++ b/ld/testsuite/ld-plugin/lto.exp
@@ -497,6 +497,31 @@ set lto_link_elf_tests [list \
    "pr28879" \
    "c++" \
   ] \
+  [list \
+   "Build libpr28849a.so" \
+   "-shared" \
+   "-fPIC" \
+   {pr28849a.c} \
+   "" \
+   "libpr28849a.so" \
+  ] \
+  [list \
+   "Build libpr28849b.so" \
+   "-shared -Wl,--no-as-needed,tmpdir/libpr28849a.so" \
+   "" \
+   {dummy.c} \
+   "" \
+   "libpr28849b.so" \
+  ] \
+  [list \
+   "Build pr28849" \
+   "-Wl,--no-as-needed,--copy-dt-needed-entries,-rpath-link,. \
+    tmpdir/libpr28849b.so" \
+   "-O2 -flto" \
+   {pr28849b.c} \
+   {{"nm" {-D} "pr28849.d"}} \
+   "pr28849" \
+  ] \
 ]
 
 # PR 14918 checks that libgcc is not spuriously included in a shared link of
diff --git a/ld/testsuite/ld-plugin/pr28849.d b/ld/testsuite/ld-plugin/pr28849.d
new file mode 100644
index 00000000000..a1f90c1ac8c
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr28849.d
@@ -0,0 +1,3 @@
+#...
+[0-9a-f]+ T _?should_be_dynamic_in_exec
+#pass
diff --git a/ld/testsuite/ld-plugin/pr28849a.c b/ld/testsuite/ld-plugin/pr28849a.c
new file mode 100644
index 00000000000..2fc5c7b052b
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr28849a.c
@@ -0,0 +1,2 @@
+extern void should_be_dynamic_in_exec (void);
+void y (void) { should_be_dynamic_in_exec (); }
diff --git a/ld/testsuite/ld-plugin/pr28849b.c b/ld/testsuite/ld-plugin/pr28849b.c
new file mode 100644
index 00000000000..616d9a585d2
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr28849b.c
@@ -0,0 +1,3 @@
+extern void y (void);
+void should_be_dynamic_in_exec (void) {}
+int main (void) { y (); return 0; }
-- 
2.35.1