Display the reference causing a shared library to be needed

[Alan Modra <amodra at gmail dot com>]

Adds a section for --as-needed libraries to a linker map file, similar
to what we do for archive libraries.

bfd/
	* elflink.c (elf_link_add_object_symbols): Call minfo for --as-needed.
ld/
	* ldlang.c (asneeded_list_head, asneeded_list_tail): New vars.
	(lang_init): Initialise them.
	(lang_print_asneeded): New function.
	(lang_process): Call lang_print_asneeded.
	* ldlang.h (struct asneeded_minfo): New.
	(asneeded_list_tail): Declare.
	* ldmain.c (add_archive_element): Improve archive map heading.
	* ldmisc.c (minfo): Stash --as-needed info.

diff --git a/bfd/elflink.c b/bfd/elflink.c
index 792e14e..88967c8 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -4437,6 +4437,9 @@ error_free_dyn:
 	      int ret;
 	      const char *soname = elf_dt_name (abfd);
 
+	      info->callbacks->minfo ("%!", soname, old_bfd,
+				      h->root.root.string);
+
 	      /* A symbol from a library loaded via DT_NEEDED of some
 		 other library is referenced by a regular object.
 		 Add a DT_NEEDED entry for it.  Issue an error if
diff --git a/ld/ldlang.c b/ld/ldlang.c
index 62f85bc..1a0d48f 100644
--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -67,6 +67,7 @@ static struct bfd_hash_table lang_definedness_table;
 static lang_statement_list_type *stat_save[10];
 static lang_statement_list_type **stat_save_ptr = &stat_save[0];
 static struct unique_sections *unique_section_list;
+static struct asneeded_minfo *asneeded_list_head;
 
 /* Forward declarations.  */
 static void exp_init_os (etree_type *);
@@ -105,6 +106,7 @@ bfd_boolean lang_float_flag = FALSE;
 bfd_boolean delete_output_file_on_failure = FALSE;
 struct lang_phdr *lang_phdr_list;
 struct lang_nocrossrefs *nocrossref_list;
+struct asneeded_minfo **asneeded_list_tail;
 
  /* Functions that traverse the linker script and might evaluate
     DEFINED() need to increment this at the start of the traversal.  */
@@ -1228,6 +1230,9 @@ lang_init (void)
 			      sizeof (struct lang_definedness_hash_entry),
 			      13))
     einfo (_("%P%F: can not create hash table: %E\n"));
+
+  asneeded_list_head = NULL;
+  asneeded_list_tail = &asneeded_list_head;
 }
 
 void
@@ -1954,6 +1959,43 @@ lang_insert_orphan (asection *s,
 }
 
 static void
+lang_print_asneeded (void)
+{
+  struct asneeded_minfo *m;
+  char buf[100];
+
+  if (asneeded_list_head == NULL)
+    return;
+
+  sprintf (buf, _("\nAs-needed library included "
+		  "to satisfy reference by file (symbol)\n\n"));
+  minfo ("%s", buf);
+
+  for (m = asneeded_list_head; m != NULL; m = m->next)
+    {
+      size_t len;
+
+      minfo ("%s", m->soname);
+      len = strlen (m->soname);
+
+      if (len >= 29)
+	{
+	  print_nl ();
+	  len = 0;
+	}
+      while (len < 30)
+	{
+	  print_space ();
+	  ++len;
+	}
+
+      if (m->ref != NULL)
+	minfo ("%B ", m->ref);
+      minfo ("(%T)\n", m->name);
+    }
+}
+
+static void
 lang_map_flags (flagword flag)
 {
   if (flag & SEC_ALLOC)
@@ -6629,6 +6671,8 @@ lang_process (void)
     link_info.gc_sym_list = ldlang_undef_chain_list_head;
 
   ldemul_after_open ();
+  if (config.map_file != NULL)
+    lang_print_asneeded ();
 
   bfd_section_already_linked_table_free ();
 
diff --git a/ld/ldlang.h b/ld/ldlang.h
index c64ded0..7236c1c 100644
--- a/ld/ldlang.h
+++ b/ld/ldlang.h
@@ -487,6 +487,14 @@ struct orphan_save
   lang_output_section_statement_type **os_tail;
 };
 
+struct asneeded_minfo
+{
+  struct asneeded_minfo *next;
+  const char *soname;
+  bfd *ref;
+  const char *name;
+};
+
 extern struct lang_phdr *lang_phdr_list;
 extern struct lang_nocrossrefs *nocrossref_list;
 extern const char *output_target;
@@ -505,6 +513,7 @@ extern lang_statement_list_type file_chain;
 extern lang_statement_list_type input_file_chain;
 
 extern int lang_statement_iteration;
+extern struct asneeded_minfo **asneeded_list_tail;
 
 extern void lang_init
   (void);
diff --git a/ld/ldmain.c b/ld/ldmain.c
index 019df71..00f79ec 100644
--- a/ld/ldmain.c
+++ b/ld/ldmain.c
@@ -841,7 +841,8 @@ add_archive_element (struct bfd_link_info *info,
 	{
 	  char buf[100];
 
-	  sprintf (buf, _("Archive member included because of file (symbol)\n\n"));
+	  sprintf (buf, _("Archive member included "
+			  "to satisfy reference by file (symbol)\n\n"));
 	  minfo ("%s", buf);
 	  header_printed = TRUE;
 	}
diff --git a/ld/ldmisc.c b/ld/ldmisc.c
index 1b69ab1..cddcb18 100644
--- a/ld/ldmisc.c
+++ b/ld/ldmisc.c
@@ -484,7 +484,22 @@ minfo (const char *fmt, ...)
       va_list arg;
 
       va_start (arg, fmt);
-      vfinfo (config.map_file, fmt, arg, FALSE);
+      if (fmt[0] == '%' && fmt[1] == '!' && fmt[2] == 0)
+	{
+	  /* Stash info about --as-needed shared libraries.  Print
+	     later so they don't appear intermingled with archive
+	     library info.  */
+	  struct asneeded_minfo *m = xmalloc (sizeof *m);
+
+	  m->next = NULL;
+	  m->soname = va_arg (arg, const char *);
+	  m->ref = va_arg (arg, bfd *);
+	  m->name = va_arg (arg, const char *);
+	  *asneeded_list_tail = m;
+	  asneeded_list_tail = &m->next;
+	}
+      else
+	vfinfo (config.map_file, fmt, arg, FALSE);
       va_end (arg);
     }
 }

-- 
Alan Modra
Australia Development Lab, IBM