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[pf3gnuchains/gcc-fork.git] / gcc / stor-layout.c
index 6826678..cffb81c 100644 (file)
@@ -1,6 +1,6 @@
 /* C-compiler utilities for types and variables storage layout
    Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1996, 1998,
-   1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+   1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -47,10 +47,6 @@ unsigned int maximum_field_alignment = TARGET_DEFAULT_PACK_STRUCT * BITS_PER_UNI
 /* ... and its original value in bytes, specified via -fpack-struct=<value>.  */
 unsigned int initial_max_fld_align = TARGET_DEFAULT_PACK_STRUCT;
 
-/* If nonzero, the alignment of a bitstring or (power-)set value, in bits.
-   May be overridden by front-ends.  */
-unsigned int set_alignment = 0;
-
 /* Nonzero if all REFERENCE_TYPEs are internal and hence should be
    allocated in Pmode, not ptr_mode.   Set only by internal_reference_types
    called only by a front end.  */
@@ -455,9 +451,9 @@ layout_decl (tree decl, unsigned int known_align)
          int size_as_int = TREE_INT_CST_LOW (size);
 
          if (compare_tree_int (size, size_as_int) == 0)
-           warning ("%Jsize of %qD is %d bytes", decl, decl, size_as_int);
+           warning (0, "%Jsize of %qD is %d bytes", decl, decl, size_as_int);
          else
-           warning ("%Jsize of %qD is larger than %d bytes",
+           warning (0, "%Jsize of %qD is larger than %d bytes",
                      decl, decl, larger_than_size);
        }
     }
@@ -489,7 +485,7 @@ relayout_decl (tree decl)
 /* Hook for a front-end function that can modify the record layout as needed
    immediately before it is finalized.  */
 
-void (*lang_adjust_rli) (record_layout_info) = 0;
+static void (*lang_adjust_rli) (record_layout_info) = 0;
 
 void
 set_lang_adjust_rli (void (*f) (record_layout_info))
@@ -638,9 +634,9 @@ rli_size_so_far (record_layout_info rli)
 }
 
 /* FIELD is about to be added to RLI->T.  The alignment (in bits) of
-   the next available location is given by KNOWN_ALIGN.  Update the
-   variable alignment fields in RLI, and return the alignment to give
-   the FIELD.  */
+   the next available location within the record is given by KNOWN_ALIGN.
+   Update the variable alignment fields in RLI, and return the alignment
+   to give the FIELD.  */
 
 unsigned int
 update_alignment_for_field (record_layout_info rli, tree field,
@@ -686,6 +682,18 @@ update_alignment_for_field (record_layout_info rli, tree field,
            type_align = MIN (type_align, maximum_field_alignment);
          rli->record_align = MAX (rli->record_align, type_align);
          rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
+         /* If we start a new run, make sure we start it properly aligned.  */
+         if ((!rli->prev_field
+              || integer_zerop (DECL_SIZE (field))
+              || integer_zerop (DECL_SIZE (rli->prev_field))
+              || !host_integerp (DECL_SIZE (rli->prev_field), 0)
+              || !host_integerp (TYPE_SIZE (type), 0)
+              || !simple_cst_equal (TYPE_SIZE (type),
+                                    TYPE_SIZE (TREE_TYPE (rli->prev_field)))
+              || (rli->remaining_in_alignment
+                  < tree_low_cst (DECL_SIZE (field), 0)))
+             && desired_align < type_align)
+           desired_align = type_align;
        }
     }
 #ifdef PCC_BITFIELD_TYPE_MATTERS
@@ -750,9 +758,9 @@ place_union_field (record_layout_info rli, tree field)
   if (TREE_CODE (rli->t) == UNION_TYPE)
     rli->offset = size_binop (MAX_EXPR, rli->offset, DECL_SIZE_UNIT (field));
   else if (TREE_CODE (rli->t) == QUAL_UNION_TYPE)
-    rli->offset = fold (build3 (COND_EXPR, sizetype,
-                               DECL_QUALIFIER (field),
-                               DECL_SIZE_UNIT (field), rli->offset));
+    rli->offset = fold_build3 (COND_EXPR, sizetype,
+                              DECL_QUALIFIER (field),
+                              DECL_SIZE_UNIT (field), rli->offset);
 }
 
 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
@@ -824,7 +832,7 @@ place_field (record_layout_info rli, tree field)
     known_align = (tree_low_cst (rli->bitpos, 1)
                   & - tree_low_cst (rli->bitpos, 1));
   else if (integer_zerop (rli->offset))
-    known_align = BIGGEST_ALIGNMENT;
+    known_align = 0;
   else if (host_integerp (rli->offset, 1))
     known_align = (BITS_PER_UNIT
                   * (tree_low_cst (rli->offset, 1)
@@ -833,6 +841,8 @@ place_field (record_layout_info rli, tree field)
     known_align = rli->offset_align;
 
   desired_align = update_alignment_for_field (rli, field, known_align);
+  if (known_align == 0)
+    known_align = MAX (BIGGEST_ALIGNMENT, rli->record_align);
 
   if (warn_packed && DECL_PACKED (field))
     {
@@ -841,10 +851,10 @@ place_field (record_layout_info rli, tree field)
          if (TYPE_ALIGN (type) > desired_align)
            {
              if (STRICT_ALIGNMENT)
-               warning ("%Jpacked attribute causes inefficient alignment "
+               warning (0, "%Jpacked attribute causes inefficient alignment "
                          "for %qD", field, field);
              else
-               warning ("%Jpacked attribute is unnecessary for %qD",
+               warning (0, "%Jpacked attribute is unnecessary for %qD",
                         field, field);
            }
        }
@@ -860,7 +870,7 @@ place_field (record_layout_info rli, tree field)
         Bump the cumulative size to multiple of field alignment.  */
 
       if (warn_padded)
-       warning ("%Jpadding struct to align %qD", field, field);
+       warning (0, "%Jpadding struct to align %qD", field, field);
 
       /* If the alignment is still within offset_align, just align
         the bit position.  */
@@ -1005,18 +1015,30 @@ place_field (record_layout_info rli, tree field)
 
              if (rli->remaining_in_alignment < bitsize)
                {
-                 /* out of bits; bump up to next 'word'.  */
-                 rli->offset = DECL_FIELD_OFFSET (rli->prev_field);
-                 rli->bitpos
-                   = size_binop (PLUS_EXPR, TYPE_SIZE (type),
-                                 DECL_FIELD_BIT_OFFSET (rli->prev_field));
-                 rli->prev_field = field;
-                 rli->remaining_in_alignment
-                   = tree_low_cst (TYPE_SIZE (type), 0);
+                 /* If PREV_FIELD is packed, and we haven't lumped
+                    non-packed bitfields with it, treat this as if PREV_FIELD
+                    was not a bitfield.  This avoids anomalies where a packed
+                    bitfield with long long base type can take up more
+                    space than a same-size bitfield with base type short.  */
+                 if (rli->prev_packed)
+                   rli->prev_field = prev_saved = NULL;
+                 else
+                   {
+                     /* out of bits; bump up to next 'word'.  */
+                     rli->offset = DECL_FIELD_OFFSET (rli->prev_field);
+                     rli->bitpos
+                       = size_binop (PLUS_EXPR, TYPE_SIZE (type),
+                                     DECL_FIELD_BIT_OFFSET (rli->prev_field));
+                     rli->prev_field = field;
+                     rli->remaining_in_alignment
+                       = tree_low_cst (TYPE_SIZE (type), 0) - bitsize;
+                   }
                }
-
-             rli->remaining_in_alignment -= bitsize;
+             else
+               rli->remaining_in_alignment -= bitsize;
            }
+         else if (rli->prev_packed)
+           rli->prev_field = prev_saved = NULL;
          else
            {
              /* End of a run: if leaving a run of bitfields of the same type
@@ -1032,9 +1054,14 @@ place_field (record_layout_info rli, tree field)
                {
                  tree type_size = TYPE_SIZE (TREE_TYPE (rli->prev_field));
 
-                 rli->bitpos
-                   = size_binop (PLUS_EXPR, type_size,
-                                 DECL_FIELD_BIT_OFFSET (rli->prev_field));
+                 /* If the desired alignment is greater or equal to TYPE_SIZE,
+                    we have already adjusted rli->bitpos / rli->offset above.
+                  */
+                 if ((unsigned HOST_WIDE_INT) tree_low_cst (type_size, 0)
+                     > desired_align)
+                   rli->bitpos
+                     = size_binop (PLUS_EXPR, type_size,
+                                   DECL_FIELD_BIT_OFFSET (rli->prev_field));
                }
              else
                /* We "use up" size zero fields; the code below should behave
@@ -1048,6 +1075,7 @@ place_field (record_layout_info rli, tree field)
                rli->prev_field = NULL;
            }
 
+         rli->prev_packed = 0;
          normalize_rli (rli);
         }
 
@@ -1120,20 +1148,59 @@ place_field (record_layout_info rli, tree field)
     actual_align = (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
                    & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1));
   else if (integer_zerop (DECL_FIELD_OFFSET (field)))
-    actual_align = BIGGEST_ALIGNMENT;
+    actual_align = MAX (BIGGEST_ALIGNMENT, rli->record_align);
   else if (host_integerp (DECL_FIELD_OFFSET (field), 1))
     actual_align = (BITS_PER_UNIT
                   * (tree_low_cst (DECL_FIELD_OFFSET (field), 1)
                      & - tree_low_cst (DECL_FIELD_OFFSET (field), 1)));
   else
     actual_align = DECL_OFFSET_ALIGN (field);
+  /* ACTUAL_ALIGN is still the actual alignment *within the record* .
+     store / extract bit field operations will check the alignment of the
+     record against the mode of bit fields.  */
 
   if (known_align != actual_align)
     layout_decl (field, actual_align);
 
-  /* Only the MS bitfields use this.  */
-  if (rli->prev_field == NULL && DECL_BIT_FIELD_TYPE(field))
-      rli->prev_field = field;
+  if (DECL_BIT_FIELD_TYPE (field))
+    {
+      unsigned int type_align = TYPE_ALIGN (type);
+
+      /* Only the MS bitfields use this.  We used to also put any kind of
+        packed bit fields into prev_field, but that makes no sense, because
+        an 8 bit packed bit field shouldn't impose more restriction on
+        following fields than a char field, and the alignment requirements
+        are also not fulfilled.
+        There is no sane value to set rli->remaining_in_alignment to when
+        a packed bitfield in prev_field is unaligned.  */
+      if (maximum_field_alignment != 0)
+       type_align = MIN (type_align, maximum_field_alignment);
+      gcc_assert (rli->prev_field
+                 || actual_align >= type_align || DECL_PACKED (field)
+                 || integer_zerop (DECL_SIZE (field))
+                 || !targetm.ms_bitfield_layout_p (rli->t));
+      if (rli->prev_field == NULL && actual_align >= type_align
+         && !integer_zerop (DECL_SIZE (field)))
+       {
+         rli->prev_field = field;
+         /* rli->remaining_in_alignment has not been set if the bitfield
+            has size zero, or if it is a packed bitfield.  */
+         rli->remaining_in_alignment
+           = (tree_low_cst (TYPE_SIZE (TREE_TYPE (field)), 0)
+              - tree_low_cst (DECL_SIZE (field), 0));
+         rli->prev_packed = DECL_PACKED (field);
+
+       }
+      else if (rli->prev_field && DECL_PACKED (field))
+       {
+         HOST_WIDE_INT bitsize = tree_low_cst (DECL_SIZE (field), 0);
+
+         if (rli->remaining_in_alignment < bitsize)
+           rli->prev_field = NULL;
+         else
+           rli->remaining_in_alignment -= bitsize;
+       }
+    }
 
   /* Now add size of this field to the size of the record.  If the size is
      not constant, treat the field as being a multiple of bytes and just
@@ -1202,7 +1269,7 @@ finalize_record_size (record_layout_info rli)
 
   if (warn_padded && TREE_CONSTANT (unpadded_size)
       && simple_cst_equal (unpadded_size, TYPE_SIZE (rli->t)) == 0)
-    warning ("padding struct size to alignment boundary");
+    warning (0, "padding struct size to alignment boundary");
 
   if (warn_packed && TREE_CODE (rli->t) == RECORD_TYPE
       && TYPE_PACKED (rli->t) && ! rli->packed_maybe_necessary
@@ -1232,17 +1299,17 @@ finalize_record_size (record_layout_info rli)
                name = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli->t)));
 
              if (STRICT_ALIGNMENT)
-               warning ("packed attribute causes inefficient "
+               warning (0, "packed attribute causes inefficient "
                         "alignment for %qs", name);
              else
-               warning ("packed attribute is unnecessary for %qs", name);
+               warning (0, "packed attribute is unnecessary for %qs", name);
            }
          else
            {
              if (STRICT_ALIGNMENT)
-               warning ("packed attribute causes inefficient alignment");
+               warning (0, "packed attribute causes inefficient alignment");
              else
-               warning ("packed attribute is unnecessary");
+               warning (0, "packed attribute is unnecessary");
            }
        }
     }
@@ -1645,9 +1712,9 @@ layout_type (tree type)
               that (possible) negative values are handled appropriately.  */
            length = size_binop (PLUS_EXPR, size_one_node,
                                 fold_convert (sizetype,
-                                              fold (build2 (MINUS_EXPR,
-                                                            TREE_TYPE (lb),
-                                                            ub, lb))));
+                                              fold_build2 (MINUS_EXPR,
+                                                           TREE_TYPE (lb),
+                                                           ub, lb)));
 
            /* Special handling for arrays of bits (for Chill).  */
            element_size = TYPE_SIZE (element);
@@ -1763,48 +1830,6 @@ layout_type (tree type)
       }
       break;
 
-    case SET_TYPE:  /* Used by Chill and Pascal.  */
-      {
-       unsigned int alignment;
-       HOST_WIDE_INT size_in_bits;
-       HOST_WIDE_INT rounded_size;
-
-       gcc_assert (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
-                   == INTEGER_CST);
-       gcc_assert (TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type)))
-                   == INTEGER_CST);
-
-#ifndef SET_WORD_SIZE
-#define SET_WORD_SIZE BITS_PER_WORD
-#endif
-       alignment = set_alignment ? set_alignment : SET_WORD_SIZE;
-       size_in_bits
-         = (tree_low_cst (TYPE_MAX_VALUE (TYPE_DOMAIN (type)), 0)
-            - tree_low_cst (TYPE_MIN_VALUE (TYPE_DOMAIN (type)), 0) + 1);
-       rounded_size
-         = ((size_in_bits + alignment - 1) / alignment) * alignment;
-
-       if (rounded_size > (int) alignment)
-         TYPE_MODE (type) = BLKmode;
-       else
-         TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1);
-
-       TYPE_SIZE (type) = bitsize_int (rounded_size);
-       TYPE_SIZE_UNIT (type) = size_int (rounded_size / BITS_PER_UNIT);
-       TYPE_ALIGN (type) = alignment;
-       TYPE_USER_ALIGN (type) = 0;
-       TYPE_PRECISION (type) = size_in_bits;
-      }
-      break;
-
-    case FILE_TYPE:
-      /* The size may vary in different languages, so the language front end
-        should fill in the size.  */
-      TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
-      TYPE_USER_ALIGN (type) = 0;
-      TYPE_MODE  (type) = BLKmode;
-      break;
-
     default:
       gcc_unreachable ();
     }
@@ -2131,8 +2156,8 @@ get_mode_bounds (enum machine_mode mode, int sign,
       max_val = ((unsigned HOST_WIDE_INT) 1 << (size - 1) << 1) - 1;
     }
 
-  *mmin = GEN_INT (trunc_int_for_mode (min_val, target_mode));
-  *mmax = GEN_INT (trunc_int_for_mode (max_val, target_mode));
+  *mmin = gen_int_mode (min_val, target_mode);
+  *mmax = gen_int_mode (max_val, target_mode);
 }
 
 #include "gt-stor-layout.h"