ld: Support input section description keyword: REVERSE

  PR 27565
  * ldlex.l: Add REVERSE.
  * ldgram.y: Allow REVERSE to be used wherever a sorting command can be used.
  * ld.h (struct wildcard_spec): Add 'reversed' field.
  * ldlang.h (lang_wild_statement_struct): Add 'filenames_reversed' field.
  * ldlang.c (compare_sections): Add reversed parameter. (wild_sort): Reverse the comparison if requested. (print_wild_statement): Handle the reversed field.
  * ld.texi: Document the new feature.
  * NEWS: Mention the new feature.
  * testsuite/ld-scripts/sort-file-reversed-1.d: New test driver.
  * testsuite/ld-scripts/sort-file-reversed-1.t: New test source.
  * testsuite/ld-scripts/sort-file-reversed-2.t: New test source.
  * testsuite/ld-scripts/sort-file-reversed-2.d: New test driver.
  * testsuite/ld-scripts/sort-sections-reversed-1.d: New test driver.
  * testsuite/ld-scripts/sort-sections-reversed-1.t: New test source.
  * testsuite/ld-scripts/sort-sections-reversed-2.t: New test source.
  * testsuite/ld-scripts/sort-sections-reversed-2.d: New test driver.
  * testsuite/ld-scripts/sort-sections-reversed-3.d: New test driver.
  * testsuite/ld-scripts/sort-sections-reversed-3.t: New test source.

1 files changed, 36 insertions, 8 deletions

diff --git a/ld/ldlang.c b/ld/ldlang.c
index c20247a..566c2b8 100644
--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -539,7 +539,7 @@ get_init_priority (const asection *sec)
 /* Compare sections ASEC and BSEC according to SORT.  */
 
 static int
-compare_section (sort_type sort, asection *asec, asection *bsec)
+compare_section (sort_type sort, asection *asec, asection *bsec, bool reversed)
 {
   int ret;
   int a_priority, b_priority;
@@ -554,7 +554,10 @@ compare_section (sort_type sort, asection *asec, asection *bsec)
       b_priority = get_init_priority (bsec);
       if (a_priority < 0 || b_priority < 0)
 	goto sort_by_name;
-      ret = a_priority - b_priority;
+      if (reversed)
+	ret = b_priority - a_priority;
+      else
+	ret = a_priority - b_priority;
       if (ret)
 	break;
       else
@@ -568,11 +571,17 @@ compare_section (sort_type sort, asection *asec, asection *bsec)
 
     case by_name:
     sort_by_name:
-      ret = strcmp (bfd_section_name (asec), bfd_section_name (bsec));
+      if (reversed)
+	ret = strcmp (bfd_section_name (bsec), bfd_section_name (asec));
+      else
+	ret = strcmp (bfd_section_name (asec), bfd_section_name (bsec));
       break;
 
     case by_name_alignment:
-      ret = strcmp (bfd_section_name (asec), bfd_section_name (bsec));
+      if (reversed)
+	ret = strcmp (bfd_section_name (bsec), bfd_section_name (asec));
+      else
+	ret = strcmp (bfd_section_name (asec), bfd_section_name (bsec));
       if (ret)
 	break;
       /* Fall through.  */
@@ -647,7 +656,11 @@ wild_sort (lang_wild_statement_type *wild,
 	  else
 	    ln = sort_filename (lsec->owner);
 
-	  i = filename_cmp (fn, ln);
+	  if (wild->filenames_reversed)
+	    i = filename_cmp (ln, fn);
+	  else
+	    i = filename_cmp (fn, ln);
+
 	  if (i > 0)
 	    { tree = &((*tree)->right); continue; }
 	  else if (i < 0)
@@ -660,7 +673,11 @@ wild_sort (lang_wild_statement_type *wild,
 	      if (la)
 		ln = sort_filename (lsec->owner);
 
-	      i = filename_cmp (fn, ln);
+	      if (wild->filenames_reversed)
+		i = filename_cmp (ln, fn);
+	      else
+		i = filename_cmp (fn, ln);
+	      
 	      if (i > 0)
 		{ tree = &((*tree)->right); continue; }
 	      else if (i < 0)
@@ -673,7 +690,7 @@ wild_sort (lang_wild_statement_type *wild,
 
       /* Find the correct node to append this section.  */
       if (sec && sec->spec.sorted != none && sec->spec.sorted != by_none
-	  && compare_section (sec->spec.sorted, section, (*tree)->section) < 0)
+	  && compare_section (sec->spec.sorted, section, (*tree)->section, sec->spec.reversed) < 0)
 	tree = &((*tree)->left);
       else
 	tree = &((*tree)->right);
@@ -5151,10 +5168,14 @@ print_wild_statement (lang_wild_statement_type *w,
 
   if (w->filenames_sorted)
     minfo ("SORT_BY_NAME(");
+  if (w->filenames_reversed)
+    minfo ("REVERSE(");
   if (w->filename != NULL)
     minfo ("%s", w->filename);
   else
     minfo ("*");
+  if (w->filenames_reversed)
+    minfo (")");
   if (w->filenames_sorted)
     minfo (")");
 
@@ -5199,6 +5220,12 @@ print_wild_statement (lang_wild_statement_type *w,
 	  break;
 	}
 
+      if (sec->spec.reversed)
+	{
+	  minfo ("REVERSE(");
+	  closing_paren++;
+	}
+
       if (sec->spec.exclude_name_list != NULL)
 	{
 	  name_list *tmp;
@@ -8500,9 +8527,10 @@ lang_add_wild (struct wildcard_spec *filespec,
   if (filespec != NULL)
     {
       new_stmt->filename = filespec->name;
-      new_stmt->filenames_sorted = filespec->sorted == by_name;
+      new_stmt->filenames_sorted = (filespec->sorted == by_name || filespec->reversed);
       new_stmt->section_flag_list = filespec->section_flag_list;
       new_stmt->exclude_name_list = filespec->exclude_name_list;
+      new_stmt->filenames_reversed = filespec->reversed;
     }
   new_stmt->section_list = section_list;
   new_stmt->keep_sections = keep_sections;