* class.c (layout_empty_base): Handle empty bases with non-byte

	alignment.
	(build_base_field): Likewise.
	(layout_virtual_bases): Likewise.

	* class.c (finish_struct_1): Fix typo in this change:

	Sat Mar 25 09:12:10 2000  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@32750 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 58c0323..970be62 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,14 @@
+2000-03-26  Mark Mitchell  <mark@codesourcery.com>
+
+       * class.c (layout_empty_base): Handle empty bases with non-byte
+       alignment.
+       (build_base_field): Likewise.
+       (layout_virtual_bases): Likewise.
+
+       * class.c (finish_struct_1): Fix typo in this change:
+       
+       Sat Mar 25 09:12:10 2000  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>
+
 2000-03-25  Mark Mitchell  <mark@codesourcery.com>
 
        * decl.c (grokdeclarator): Count partial specializations when

diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index 789ce45..fe636a2 100644 (file)
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -4267,8 +4267,9 @@ layout_nonempty_base_or_field (rli, decl, binfo, v)
 }
 
 /* Layout the empty base BINFO.  EOC indicates the byte currently just
-   past the end of the class; BINFO_OFFSETS gives the offsets of the
-   other bases allocated so far.  */
+   past the end of the class, and should be correctly aligned for a
+   class of the type indicated by BINFO; BINFO_OFFSETS gives the
+   offsets of the other bases allocated so far.  */
 
 static void
 layout_empty_base (binfo, eoc, binfo_offsets)
@@ -4276,16 +4277,12 @@ layout_empty_base (binfo, eoc, binfo_offsets)
      tree eoc;
      varray_type binfo_offsets;
 {
+  tree alignment;
   tree basetype = BINFO_TYPE (binfo);
   
   /* This routine should only be used for empty classes.  */
   my_friendly_assert (is_empty_class (basetype), 20000321);
-
-  /* This code assumes that zero-sized classes have one-byte
-     alignment.  There might someday be a system where that's not
-     true.  */
-  my_friendly_assert (TYPE_ALIGN (basetype) == BITS_PER_UNIT, 
-                     20000314);
+  alignment = ssize_int (CLASSTYPE_ALIGN (basetype));
 
   /* This is an empty base class.  We first try to put it at offset
      zero.  */
@@ -4301,7 +4298,7 @@ layout_empty_base (binfo, eoc, binfo_offsets)
            break;
 
          /* There's overlap here, too.  Bump along to the next spot.  */
-         propagate_binfo_offsets (binfo, ssize_int (1));
+         propagate_binfo_offsets (binfo, alignment);
        }
     }
 }
@@ -4360,7 +4357,15 @@ build_base_field (rli, binfo, empty_p, base_align, v)
       layout_nonempty_base_or_field (rli, decl, binfo, *v);
     }
   else
-    layout_empty_base (binfo, rli_size_unit_so_far (rli), *v);
+    {
+      unsigned HOST_WIDE_INT eoc;
+
+      /* On some platforms (ARM), even empty classes will not be
+        byte-aligned.  */
+      eoc = tree_low_cst (rli_size_unit_so_far (rli), 0);
+      eoc = CEIL (eoc, DECL_ALIGN (decl)) * DECL_ALIGN (decl);
+      layout_empty_base (binfo, size_int (eoc), *v);
+    }
 
   /* Check for inaccessible base classes.  If the same base class
      appears more than once in the hierarchy, but isn't virtual, then
@@ -4847,6 +4852,19 @@ layout_virtual_bases (t, base_offsets)
 
        basetype = BINFO_TYPE (vbase);
 
+       if (flag_new_abi)
+         desired_align = CLASSTYPE_ALIGN (basetype);
+       else
+         /* Under the old ABI, virtual bases were aligned as for the
+            entire base object (including its virtual bases).  That's
+            wasteful, in general.  */
+         desired_align = TYPE_ALIGN (basetype);
+       TYPE_ALIGN (t) = MAX (TYPE_ALIGN (t), desired_align);
+
+       /* Add padding so that we can put the virtual base class at an
+          appropriately aligned offset.  */
+       dsize = CEIL (dsize, desired_align) * desired_align;
+
        /* Under the new ABI, we try to squish empty virtual bases in
           just like ordinary empty bases.  */
        if (flag_new_abi && is_empty_class (basetype))
@@ -4855,18 +4873,6 @@ layout_virtual_bases (t, base_offsets)
                             *base_offsets);
        else
          {
-           if (flag_new_abi)
-             desired_align = CLASSTYPE_ALIGN (basetype);
-           else
-             /* Under the old ABI, virtual bases were aligned as for
-                the entire base object (including its virtual bases).
-                That's wasteful, in general.  */
-             desired_align = TYPE_ALIGN (basetype);
-           TYPE_ALIGN (t) = MAX (TYPE_ALIGN (t), desired_align);
-
-           /* Add padding so that we can put the virtual base class at an
-              appropriately aligned offset.  */
-           dsize = CEIL (dsize, desired_align) * desired_align;
            /* And compute the offset of the virtual base.  */
            propagate_binfo_offsets (vbase, 
                                     ssize_int (CEIL (dsize, BITS_PER_UNIT)));
@@ -5262,14 +5268,15 @@ finish_struct_1 (t)
   if (vfield != NULL_TREE
       && DECL_FIELD_CONTEXT (vfield) != t)
     {
+      tree binfo = get_binfo (DECL_FIELD_CONTEXT (vfield), t, 0);
+
       vfield = copy_node (vfield);
       copy_lang_decl (vfield);
 
       DECL_FIELD_CONTEXT (vfield) = t;
       DECL_FIELD_OFFSET (vfield)
        = size_binop (PLUS_EXPR,
-                     BINFO_OFFSET (get_binfo (DECL_FIELD_CONTEXT (vfield),
-                                              t, 0)),
+                     BINFO_OFFSET (binfo),
                      DECL_FIELD_OFFSET (vfield));
       TYPE_VFIELD (t) = vfield;
     }