/* C-compiler utilities for types and variables storage layout
Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1996, 1998,
- 1999, 2000, 2001 Free Software Foundation, Inc.
+ 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
This file is part of GCC.
#include "expr.h"
#include "toplev.h"
#include "ggc.h"
+#include "target.h"
+#include "langhooks.h"
/* Set to one when set_sizetype has been called. */
static int sizetype_set;
\f
/* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
-static tree pending_sizes;
+static GTY(()) tree pending_sizes;
/* Nonzero means cannot safely call expand_expr now,
so put variable sizes onto `pending_sizes' instead. */
just return SIZE unchanged. Likewise for self-referential sizes and
constant sizes. */
if (TREE_CONSTANT (size)
- || global_bindings_p () < 0 || contains_placeholder_p (size))
+ || (*lang_hooks.decls.global_bindings_p) () < 0
+ || contains_placeholder_p (size))
return size;
size = save_expr (size);
if (TREE_CODE (size) == SAVE_EXPR)
SAVE_EXPR_PERSISTENT_P (size) = 1;
- if (global_bindings_p ())
+ if ((*lang_hooks.decls.global_bindings_p) ())
{
if (TREE_CONSTANT (size))
error ("type size can't be explicitly evaluated");
}
if (immediate_size_expand)
- /* NULL_RTX is not defined; neither is the rtx type.
+ /* NULL_RTX is not defined; neither is the rtx type.
Also, we would like to pass const0_rtx here, but don't have it. */
expand_expr (size, expand_expr (integer_zero_node, NULL_RTX, VOIDmode, 0),
VOIDmode, 0);
case MODE_RANDOM:
if (mode == BLKmode)
- break;
+ break;
/* ... fall through ... */
&& (DECL_ALIGN (decl) == 0
|| (! (code == FIELD_DECL && DECL_PACKED (decl))
&& TYPE_ALIGN (type) > DECL_ALIGN (decl))))
- {
+ {
DECL_ALIGN (decl) = TYPE_ALIGN (type);
DECL_USER_ALIGN (decl) = 0;
}
DECL_BIT_FIELD_TYPE (decl) = DECL_BIT_FIELD (decl) ? type : 0;
if (maximum_field_alignment != 0)
DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
- else if (DECL_PACKED (decl))
+
+ /* If the field is of variable size, we can't misalign it since we
+ have no way to make a temporary to align the result. But this
+ isn't an issue if the decl is not addressable. Likewise if it
+ is of unknown size. */
+ else if (DECL_PACKED (decl)
+ && (DECL_NONADDRESSABLE_P (decl)
+ || DECL_SIZE_UNIT (decl) == 0
+ || TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST))
{
DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), BITS_PER_UNIT);
DECL_USER_ALIGN (decl) = 0;
}
}
- /* See if we can use an ordinary integer mode for a bit-field.
+ /* See if we can use an ordinary integer mode for a bit-field.
Conditions are: a fixed size that is correct for another mode
and occupying a complete byte or bytes on proper boundary. */
if (code == FIELD_DECL && DECL_BIT_FIELD (decl)
/* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
is to be passed to all other layout functions for this record. It is the
- responsibility of the caller to call `free' for the storage returned.
+ responsibility of the caller to call `free' for the storage returned.
Note that garbage collection is not permitted until we finish laying
out the record. */
start_record_layout (t)
tree t;
{
- record_layout_info rli
+ record_layout_info rli
= (record_layout_info) xmalloc (sizeof (struct record_layout_info_s));
rli->t = t;
rli->offset = size_zero_node;
rli->bitpos = bitsize_zero_node;
+ rli->prev_field = 0;
rli->pending_statics = 0;
rli->packed_maybe_necessary = 0;
= size_binop (PLUS_EXPR, *poffset,
size_binop (MULT_EXPR, convert (sizetype, extra_aligns),
size_int (off_align / BITS_PER_UNIT)));
-
+
*pbitpos
= size_binop (FLOOR_MOD_EXPR, *pbitpos, bitsize_int (off_align));
}
unsigned int desired_align;
layout_decl (field, 0);
-
+
DECL_FIELD_OFFSET (field) = size_zero_node;
DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node;
SET_DECL_OFFSET_ALIGN (field, BIGGEST_ALIGNMENT);
#endif
#ifdef ADJUST_FIELD_ALIGN
- desired_align = ADJUST_FIELD_ALIGN (field, desired_align);
+ if (! DECL_USER_ALIGN (field))
+ desired_align = ADJUST_FIELD_ALIGN (field, desired_align);
#endif
TYPE_USER_ALIGN (rli->t) |= DECL_USER_ALIGN (field);
entire union to have `int' alignment. */
if (PCC_BITFIELD_TYPE_MATTERS && DECL_BIT_FIELD_TYPE (field))
{
- rli->record_align = MAX (rli->record_align,
- TYPE_ALIGN (TREE_TYPE (field)));
- rli->unpadded_align = MAX (rli->unpadded_align,
- TYPE_ALIGN (TREE_TYPE (field)));
+ unsigned int type_align = TYPE_ALIGN (TREE_TYPE (field));
+
+#ifdef ADJUST_FIELD_ALIGN
+ if (! TYPE_USER_ALIGN (TREE_TYPE (field)))
+ type_align = ADJUST_FIELD_ALIGN (field, type_align);
+#endif
+ rli->record_align = MAX (rli->record_align, type_align);
+ rli->unpadded_align = MAX (rli->unpadded_align, type_align);
+ TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (TREE_TYPE (field));
}
#endif
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 (build (COND_EXPR, sizetype,
+ rli->offset = fold (build (COND_EXPR, sizetype,
DECL_QUALIFIER (field),
DECL_SIZE_UNIT (field), rli->offset));
}
unsigned int user_align;
/* The type of this field. */
tree type = TREE_TYPE (field);
-
+
if (TREE_CODE (field) == ERROR_MARK || TREE_CODE (type) == ERROR_MARK)
return;
#endif
#ifdef ADJUST_FIELD_ALIGN
- desired_align = ADJUST_FIELD_ALIGN (field, desired_align);
+ if (! user_align)
+ desired_align = ADJUST_FIELD_ALIGN (field, desired_align);
#endif
/* Record must have at least as much alignment as any field.
Otherwise, the alignment of the field within the record is
meaningless. */
+ if ((* targetm.ms_bitfield_layout_p) (rli->t)
+ && type != error_mark_node
+ && DECL_BIT_FIELD_TYPE (field)
+ && ! integer_zerop (TYPE_SIZE (type)))
+ {
+ /* Here, the alignment of the underlying type of a bitfield can
+ affect the alignment of a record; even a zero-sized field
+ can do this. The alignment should be to the alignment of
+ the type, except that for zero-size bitfields this only
+ applies if there was an immediately prior, non-zero-size
+ bitfield. (That's the way it is, experimentally.) */
+ if (! integer_zerop (DECL_SIZE (field))
+ ? ! DECL_PACKED (field)
+ : (rli->prev_field
+ && DECL_BIT_FIELD_TYPE (rli->prev_field)
+ && ! integer_zerop (DECL_SIZE (rli->prev_field))))
+ {
+ unsigned int type_align = TYPE_ALIGN (type);
+ type_align = MAX (type_align, desired_align);
+ if (maximum_field_alignment != 0)
+ 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));
+ rli->unpadded_align = MAX (rli->unpadded_align, DECL_ALIGN (field));
+ }
+ else
+ desired_align = 1;
+ }
+ else
#ifdef PCC_BITFIELD_TYPE_MATTERS
if (PCC_BITFIELD_TYPE_MATTERS && type != error_mark_node
+ && ! (* targetm.ms_bitfield_layout_p) (rli->t)
&& DECL_BIT_FIELD_TYPE (field)
&& ! integer_zerop (TYPE_SIZE (type)))
{
{
unsigned int type_align = TYPE_ALIGN (type);
+#ifdef ADJUST_FIELD_ALIGN
+ if (! TYPE_USER_ALIGN (type))
+ type_align = ADJUST_FIELD_ALIGN (field, type_align);
+#endif
+
if (maximum_field_alignment != 0)
type_align = MIN (type_align, maximum_field_alignment);
else if (DECL_PACKED (field))
rli->unpadded_align = MAX (rli->unpadded_align, DECL_ALIGN (field));
if (warn_packed)
rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
+ user_align |= TYPE_USER_ALIGN (type);
}
}
else
variable-sized fields, we need not worry about compatibility. */
#ifdef PCC_BITFIELD_TYPE_MATTERS
if (PCC_BITFIELD_TYPE_MATTERS
+ && ! (* targetm.ms_bitfield_layout_p) (rli->t)
&& TREE_CODE (field) == FIELD_DECL
&& type != error_mark_node
&& DECL_BIT_FIELD (field)
HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
+#ifdef ADJUST_FIELD_ALIGN
+ if (! TYPE_USER_ALIGN (type))
+ type_align = ADJUST_FIELD_ALIGN (field, type_align);
+#endif
+
/* A bit field may not span more units of alignment of its type
than its type itself. Advance to next boundary if necessary. */
if ((((offset * BITS_PER_UNIT + bit_offset + field_size +
- (offset * BITS_PER_UNIT + bit_offset) / type_align)
> tree_low_cst (TYPE_SIZE (type), 1) / type_align)
rli->bitpos = round_up (rli->bitpos, type_align);
+
+ user_align |= TYPE_USER_ALIGN (type);
}
#endif
#ifdef BITFIELD_NBYTES_LIMITED
if (BITFIELD_NBYTES_LIMITED
+ && ! (* targetm.ms_bitfield_layout_p) (rli->t)
&& TREE_CODE (field) == FIELD_DECL
&& type != error_mark_node
&& DECL_BIT_FIELD_TYPE (field)
HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
+#ifdef ADJUST_FIELD_ALIGN
+ if (! TYPE_USER_ALIGN (type))
+ type_align = ADJUST_FIELD_ALIGN (field, type_align);
+#endif
+
if (maximum_field_alignment != 0)
type_align = MIN (type_align, maximum_field_alignment);
/* ??? This test is opposite the test in the containing if
!= ((offset * BITS_PER_UNIT + bit_offset + field_size - 1)
/ type_align))
rli->bitpos = round_up (rli->bitpos, type_align);
+
+ user_align |= TYPE_USER_ALIGN (type);
}
#endif
+ /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
+ A subtlety:
+ When a bit field is inserted into a packed record, the whole
+ size of the underlying type is used by one or more same-size
+ adjacent bitfields. (That is, if its long:3, 32 bits is
+ used in the record, and any additional adjacent long bitfields are
+ packed into the same chunk of 32 bits. However, if the size
+ changes, a new field of that size is allocated.) In an unpacked
+ record, this is the same as using alignment, but not eqivalent
+ when packing.
+
+ Note: for compatability, we use the type size, not the type alignment
+ to determine alignment, since that matches the documentation */
+
+ if ((* targetm.ms_bitfield_layout_p) (rli->t)
+ && ((DECL_BIT_FIELD_TYPE (field) && ! DECL_PACKED (field))
+ || (rli->prev_field && ! DECL_PACKED (rli->prev_field))))
+ {
+ /* At this point, either the prior or current are bitfields,
+ (possibly both), and we're dealing with MS packing. */
+ tree prev_saved = rli->prev_field;
+
+ /* Is the prior field a bitfield? If so, handle "runs" of same
+ type size fields. */
+ if (rli->prev_field /* necessarily a bitfield if it exists. */)
+ {
+ /* If both are bitfields, nonzero, and the same size, this is
+ the middle of a run. Zero declared size fields are special
+ and handled as "end of run". (Note: it's nonzero declared
+ size, but equal type sizes!) (Since we know that both
+ the current and previous fields are bitfields by the
+ time we check it, DECL_SIZE must be present for both.) */
+ if (DECL_BIT_FIELD_TYPE (field)
+ && !integer_zerop (DECL_SIZE (field))
+ && !integer_zerop (DECL_SIZE (rli->prev_field))
+ && simple_cst_equal (TYPE_SIZE (type),
+ TYPE_SIZE (TREE_TYPE (rli->prev_field))) )
+ {
+ /* We're in the middle of a run of equal type size fields; make
+ sure we realign if we run out of bits. (Not decl size,
+ type size!) */
+ int bitsize = TREE_INT_CST_LOW (DECL_SIZE (field));
+ tree type_size = TYPE_SIZE(TREE_TYPE(rli->prev_field));
+
+ if (rli->remaining_in_alignment < bitsize)
+ {
+ /* out of bits; bump up to next 'word'. */
+ rli->bitpos = size_binop (PLUS_EXPR,
+ type_size,
+ DECL_FIELD_BIT_OFFSET(rli->prev_field));
+ rli->prev_field = field;
+ rli->remaining_in_alignment = TREE_INT_CST_LOW (type_size);
+ }
+ rli->remaining_in_alignment -= bitsize;
+ }
+ else
+ {
+ /* End of a run: if leaving a run of bitfields of the same type
+ size, we have to "use up" the rest of the bits of the type
+ size.
+
+ Compute the new position as the sum of the size for the prior
+ type and where we first started working on that type.
+ Note: since the beginning of the field was aligned then
+ of course the end will be too. No round needed. */
+
+ if (!integer_zerop (DECL_SIZE (rli->prev_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));
+ }
+ else
+ {
+ /* We "use up" size zero fields; the code below should behave
+ as if the prior field was not a bitfield. */
+ prev_saved = NULL;
+ }
+
+ /* Cause a new bitfield to be captured, either this time (if
+ currently a bitfield) or next time we see one. */
+ if (!DECL_BIT_FIELD_TYPE(field)
+ || integer_zerop (DECL_SIZE (field)))
+ {
+ rli->prev_field = NULL;
+ }
+ }
+ normalize_rli (rli);
+ }
+
+ /* If we're starting a new run of same size type bitfields
+ (or a run of non-bitfields), set up the "first of the run"
+ fields.
+
+ That is, if the current field is not a bitfield, or if there
+ was a prior bitfield the type sizes differ, or if there wasn't
+ a prior bitfield the size of the current field is nonzero.
+
+ Note: we must be sure to test ONLY the type size if there was
+ a prior bitfield and ONLY for the current field being zero if
+ there wasn't. */
+
+ if (!DECL_BIT_FIELD_TYPE (field)
+ || ( prev_saved != NULL
+ ? !simple_cst_equal (TYPE_SIZE (type),
+ TYPE_SIZE (TREE_TYPE (prev_saved)))
+ : !integer_zerop (DECL_SIZE (field)) ))
+ {
+ unsigned int type_align = 8; /* Never below 8 for compatability */
+
+ /* (When not a bitfield), we could be seeing a flex array (with
+ no DECL_SIZE). Since we won't be using remaining_in_alignment
+ until we see a bitfield (and come by here again) we just skip
+ calculating it. */
+
+ if (DECL_SIZE (field) != NULL)
+ rli->remaining_in_alignment
+ = TREE_INT_CST_LOW (TYPE_SIZE(TREE_TYPE(field)))
+ - TREE_INT_CST_LOW (DECL_SIZE (field));
+
+ /* Now align (conventionally) for the new type. */
+ if (!DECL_PACKED(field))
+ type_align = MAX(TYPE_ALIGN (type), type_align);
+
+ if (prev_saved
+ && DECL_BIT_FIELD_TYPE (prev_saved)
+ /* If the previous bit-field is zero-sized, we've already
+ accounted for its alignment needs (or ignored it, if
+ appropriate) while placing it. */
+ && ! integer_zerop (DECL_SIZE (prev_saved)))
+ type_align = MAX (type_align,
+ TYPE_ALIGN (TREE_TYPE (prev_saved)));
+
+ if (maximum_field_alignment != 0)
+ type_align = MIN (type_align, maximum_field_alignment);
+
+ rli->bitpos = round_up (rli->bitpos, type_align);
+ /* If we really aligned, don't allow subsequent bitfields
+ to undo that. */
+ rli->prev_field = NULL;
+ }
+ }
+
/* Offset so far becomes the position of this field after normalizing. */
normalize_rli (rli);
DECL_FIELD_OFFSET (field) = rli->offset;
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;
+
/* 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
adjust the offset, resetting the bit position. Otherwise, apportion the
if (warn_padded && TREE_CONSTANT (unpadded_size)
&& simple_cst_equal (unpadded_size, TYPE_SIZE (rli->t)) == 0)
warning ("padding struct size to alignment boundary");
-
+
if (warn_packed && TREE_CODE (rli->t) == RECORD_TYPE
&& TYPE_PACKED (rli->t) && ! rli->packed_maybe_necessary
&& TREE_CONSTANT (unpadded_size))
return;
bitpos = int_bit_position (field);
-
+
/* Must be BLKmode if any field crosses a word boundary,
since extract_bit_field can't handle that in registers. */
if (bitpos / BITS_PER_WORD
#ifdef MEMBER_TYPE_FORCES_BLK
/* With some targets, eg. c4x, it is sub-optimal
to access an aligned BLKmode structure as a scalar. */
- if (mode == VOIDmode && MEMBER_TYPE_FORCES_BLK (field))
+
+ if (MEMBER_TYPE_FORCES_BLK (field, mode))
return;
#endif /* MEMBER_TYPE_FORCES_BLK */
}
TYPE_MODE (type) = BLKmode;
if (TYPE_SIZE (type) != 0
#ifdef MEMBER_TYPE_FORCES_BLK
- && ! MEMBER_TYPE_FORCES_BLK (type)
+ && ! MEMBER_TYPE_FORCES_BLK (type, VOIDmode)
#endif
/* BLKmode elements force BLKmode aggregate;
else extract/store fields may lose. */
&& (TYPE_MODE (TREE_TYPE (type)) != BLKmode
|| TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
{
- TYPE_MODE (type)
- = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
+ /* One-element arrays get the component type's mode. */
+ if (simple_cst_equal (TYPE_SIZE (type),
+ TYPE_SIZE (TREE_TYPE (type))))
+ TYPE_MODE (type) = TYPE_MODE (TREE_TYPE (type));
+ else
+ TYPE_MODE (type)
+ = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
if (TYPE_MODE (type) != BLKmode
&& STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
case SET_TYPE: /* Used by Chill and Pascal. */
if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST
|| TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST)
- abort();
+ abort ();
else
{
#ifndef SET_WORD_SIZE
/* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
records and unions, finish_record_layout already called this
function. */
- if (TREE_CODE (type) != RECORD_TYPE
+ if (TREE_CODE (type) != RECORD_TYPE
&& TREE_CODE (type) != UNION_TYPE
&& TREE_CODE (type) != QUAL_UNION_TYPE)
finalize_type_size (type);
TYPE_REFERENCE_TO (sizetype_tab[i]) = 0;
}
- ggc_add_tree_root ((tree *) &sizetype_tab,
- sizeof sizetype_tab / sizeof (tree));
-
/* Go down each of the types we already made and set the proper type
for the sizes in them. */
for (t = early_type_list; t != 0; t = TREE_CHAIN (t))
return mode;
}
-/* This function is run once to initialize stor-layout.c. */
-
-void
-init_stor_layout_once ()
-{
- ggc_add_tree_root (&pending_sizes, 1);
-}
+#include "gt-stor-layout.h"
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