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- /* C-compiler utilities for types and variables storage layout
- Copyright (C) 1987, 1988, 1992 Free Software Foundation, Inc.
-
- This file is part of GNU CC.
-
- GNU CC is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
- any later version.
-
- GNU CC is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with GNU CC; see the file COPYING. If not, write to
- the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
-
-
- #include "config.h"
- #include <stdio.h>
-
- #include "tree.h"
- #include "function.h"
-
- #define CEIL(x,y) (((x) + (y) - 1) / (y))
-
- /* Data type for the expressions representing sizes of data types.
- It is the first integer type laid out.
- In C, this is int. */
-
- tree sizetype;
-
- /* An integer constant with value 0 whose type is sizetype. */
-
- tree size_zero_node;
-
- /* An integer constant with value 1 whose type is sizetype. */
-
- tree size_one_node;
-
- /* If nonzero, this is an upper limit on alignment of structure fields.
- The value is measured in bits. */
- int maximum_field_alignment;
-
- #define GET_MODE_ALIGNMENT(MODE) \
- MIN (BIGGEST_ALIGNMENT, \
- MAX (1, (GET_MODE_UNIT_SIZE (MODE) * BITS_PER_UNIT)))
-
- /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
-
- static tree pending_sizes;
-
- /* Nonzero means cannot safely call expand_expr now,
- so put variable sizes onto `pending_sizes' instead. */
-
- int immediate_size_expand;
-
- tree
- get_pending_sizes ()
- {
- tree chain = pending_sizes;
- tree t;
-
- /* Put each SAVE_EXPR into the current function. */
- for (t = chain; t; t = TREE_CHAIN (t))
- SAVE_EXPR_CONTEXT (TREE_VALUE (t)) = current_function_decl;
- pending_sizes = 0;
- return chain;
- }
-
- /* Given a size SIZE that isn't constant, return a SAVE_EXPR
- to serve as the actual size-expression for a type or decl. */
-
- tree
- variable_size (size)
- tree size;
- {
- size = save_expr (size);
-
- if (global_bindings_p ())
- {
- error ("variable-size type declared outside of any function");
- return size_int (1);
- }
-
- if (immediate_size_expand)
- expand_expr (size, NULL_PTR, VOIDmode, 0);
- else
- pending_sizes = tree_cons (NULL_TREE, size, pending_sizes);
-
- return size;
- }
-
- #ifndef MAX_FIXED_MODE_SIZE
- #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
- #endif
-
- /* Return the machine mode to use for a nonscalar of SIZE bits.
- The mode must be in class CLASS, and have exactly that many bits.
- If LIMIT is nonzero, modes of wider than MAX_FIXED_MODE_SIZE will not
- be used. */
-
- enum machine_mode
- mode_for_size (size, class, limit)
- unsigned int size;
- enum mode_class class;
- int limit;
- {
- register enum machine_mode mode;
-
- if (limit && size > MAX_FIXED_MODE_SIZE)
- return BLKmode;
-
- /* Get the last mode which has this size, in the specified class. */
- for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
- mode = GET_MODE_WIDER_MODE (mode))
- if (GET_MODE_BITSIZE (mode) == size)
- return mode;
-
- return BLKmode;
- }
-
- /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
-
- tree
- round_up (value, divisor)
- tree value;
- int divisor;
- {
- return size_binop (MULT_EXPR,
- size_binop (CEIL_DIV_EXPR, value, size_int (divisor)),
- size_int (divisor));
- }
-
- /* Set the size, mode and alignment of a ..._DECL node.
- TYPE_DECL does need this for C++.
- Note that LABEL_DECL and CONST_DECL nodes do not need this,
- and FUNCTION_DECL nodes have them set up in a special (and simple) way.
- Don't call layout_decl for them.
-
- KNOWN_ALIGN is the amount of alignment we can assume this
- decl has with no special effort. It is relevant only for FIELD_DECLs
- and depends on the previous fields.
- All that matters about KNOWN_ALIGN is which powers of 2 divide it.
- If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
- the record will be aligned to suit. */
-
- void
- layout_decl (decl, known_align)
- tree decl;
- unsigned known_align;
- {
- register tree type = TREE_TYPE (decl);
- register enum tree_code code = TREE_CODE (decl);
- int spec_size = DECL_FIELD_SIZE (decl);
-
- if (code == CONST_DECL)
- return;
-
- if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
- && code != FIELD_DECL && code != TYPE_DECL)
- abort ();
-
- if (type == error_mark_node)
- {
- type = void_type_node;
- spec_size = 0;
- }
-
- /* Usually the size and mode come from the data type without change. */
-
- DECL_MODE (decl) = TYPE_MODE (type);
- DECL_SIZE (decl) = TYPE_SIZE (type);
- TREE_UNSIGNED (decl) = TREE_UNSIGNED (type);
-
- if (code == FIELD_DECL && DECL_BIT_FIELD (decl))
- {
- /* This is a bit-field. We don't know how to handle
- them except for integers and enums, and front end should
- never generate them otherwise. */
-
- if (! (TREE_CODE (type) == INTEGER_TYPE
- || TREE_CODE (type) == ENUMERAL_TYPE))
- abort ();
-
- if (spec_size == 0 && DECL_NAME (decl) != 0)
- abort ();
-
- /* Size is specified number of bits. */
- DECL_SIZE (decl) = size_int (spec_size);
- }
- /* Force alignment required for the data type.
- But if the decl itself wants greater alignment, don't override that.
- Likewise, if the decl is packed, don't override it. */
- else if (DECL_ALIGN (decl) == 0
- || (! DECL_PACKED (decl) && TYPE_ALIGN (type) > DECL_ALIGN (decl)))
- DECL_ALIGN (decl) = TYPE_ALIGN (type);
-
- /* 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_TYPE (decl) = DECL_BIT_FIELD (decl) ? type : 0;
- if (maximum_field_alignment != 0)
- DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
- }
-
- if (DECL_BIT_FIELD (decl)
- && TYPE_SIZE (type) != 0
- && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
- {
- register enum machine_mode xmode
- = mode_for_size (TREE_INT_CST_LOW (DECL_SIZE (decl)), MODE_INT, 1);
-
- if (xmode != BLKmode
- && known_align % GET_MODE_ALIGNMENT (xmode) == 0)
- {
- DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode),
- DECL_ALIGN (decl));
- DECL_MODE (decl) = xmode;
- DECL_SIZE (decl) = size_int (GET_MODE_BITSIZE (xmode));
- /* This no longer needs to be accessed as a bit field. */
- DECL_BIT_FIELD (decl) = 0;
- }
- }
-
- /* Evaluate nonconstant size only once, either now or as soon as safe. */
- if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
- DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
- }
-
- /* Lay out a RECORD_TYPE type (a C struct).
- This means laying out the fields, determining their positions,
- and computing the overall size and required alignment of the record.
- Note that if you set the TYPE_ALIGN before calling this
- then the struct is aligned to at least that boundary.
-
- If the type has basetypes, you must call layout_basetypes
- before calling this function.
-
- The return value is a list of static members of the record.
- They still need to be laid out. */
-
- static tree
- layout_record (rec)
- tree rec;
- {
- register tree field;
- #ifdef STRUCTURE_SIZE_BOUNDARY
- unsigned record_align = MAX (STRUCTURE_SIZE_BOUNDARY, TYPE_ALIGN (rec));
- #else
- unsigned record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (rec));
- #endif
- /* These must be laid out *after* the record is. */
- tree pending_statics = NULL_TREE;
- /* Record size so far is CONST_SIZE + VAR_SIZE bits,
- where CONST_SIZE is an integer
- and VAR_SIZE is a tree expression.
- If VAR_SIZE is null, the size is just CONST_SIZE.
- Naturally we try to avoid using VAR_SIZE. */
- register int const_size = 0;
- register tree var_size = 0;
- /* Once we start using VAR_SIZE, this is the maximum alignment
- that we know VAR_SIZE has. */
- register int var_align = BITS_PER_UNIT;
-
-
- for (field = TYPE_FIELDS (rec); field; field = TREE_CHAIN (field))
- {
- register int desired_align;
-
- /* If FIELD is static, then treat it like a separate variable,
- not really like a structure field.
- If it is a FUNCTION_DECL, it's a method.
- In both cases, all we do is lay out the decl,
- and we do it *after* the record is laid out. */
-
- if (TREE_STATIC (field))
- {
- pending_statics = tree_cons (NULL_TREE, field, pending_statics);
- continue;
- }
- /* Enumerators and enum types which are local to this class need not
- be laid out. Likewise for initialized constant fields. */
- if (TREE_CODE (field) != FIELD_DECL)
- continue;
-
- /* Lay out the field so we know what alignment it needs.
- For KNOWN_ALIGN, pass the number of bits from start of record
- or some divisor of it. */
-
- /* For a packed field, use the alignment as specified,
- disregarding what the type would want. */
- if (DECL_PACKED (field))
- desired_align = DECL_ALIGN (field);
- layout_decl (field, var_size ? var_align : const_size);
- if (! DECL_PACKED (field))
- desired_align = DECL_ALIGN (field);
- /* Some targets (i.e. VMS) limit struct field alignment
- to a lower boundary than alignment of variables. */
- #ifdef BIGGEST_FIELD_ALIGNMENT
- desired_align = MIN (desired_align, BIGGEST_FIELD_ALIGNMENT);
- #endif
-
- /* Record must have at least as much alignment as any field.
- Otherwise, the alignment of the field within the record
- is meaningless. */
-
- #ifndef PCC_BITFIELD_TYPE_MATTERS
- record_align = MAX (record_align, desired_align);
- #else
- if (PCC_BITFIELD_TYPE_MATTERS && TREE_TYPE (field) != error_mark_node
- && DECL_BIT_FIELD_TYPE (field)
- && ! integer_zerop (TYPE_SIZE (TREE_TYPE (field))))
- {
- /* For these machines, a zero-length field does not
- affect the alignment of the structure as a whole.
- It does, however, affect the alignment of the next field
- within the structure. */
- if (! integer_zerop (DECL_SIZE (field)))
- record_align = MAX (record_align, desired_align);
- else if (! DECL_PACKED (field))
- desired_align = TYPE_ALIGN (TREE_TYPE (field));
- /* A named bit field of declared type `int'
- forces the entire structure to have `int' alignment. */
- if (DECL_NAME (field) != 0)
- {
- int type_align = TYPE_ALIGN (TREE_TYPE (field));
- if (maximum_field_alignment != 0)
- type_align = MIN (type_align, maximum_field_alignment);
-
- record_align = MAX (record_align, type_align);
- }
- }
- else
- record_align = MAX (record_align, desired_align);
- #endif
-
- /* Does this field automatically have alignment it needs
- by virtue of the fields that precede it and the record's
- own alignment? */
-
- if (const_size % desired_align != 0
- || (var_align % desired_align != 0
- && var_size != 0))
- {
- /* No, we need to skip space before this field.
- Bump the cumulative size to multiple of field alignment. */
-
- if (var_size == 0
- || var_align % desired_align == 0)
- const_size
- = CEIL (const_size, desired_align) * desired_align;
- else
- {
- if (const_size > 0)
- var_size = size_binop (PLUS_EXPR, var_size,
- size_int (const_size));
- const_size = 0;
- var_size = round_up (var_size, desired_align);
- var_align = MIN (var_align, desired_align);
- }
- }
-
- #ifdef PCC_BITFIELD_TYPE_MATTERS
- if (PCC_BITFIELD_TYPE_MATTERS
- && TREE_CODE (field) == FIELD_DECL
- && TREE_TYPE (field) != error_mark_node
- && DECL_BIT_FIELD_TYPE (field)
- && !DECL_PACKED (field)
- && !integer_zerop (DECL_SIZE (field)))
- {
- int type_align = TYPE_ALIGN (TREE_TYPE (field));
- register tree dsize = DECL_SIZE (field);
- int field_size = TREE_INT_CST_LOW (dsize);
-
- if (maximum_field_alignment != 0)
- type_align = MIN (type_align, maximum_field_alignment);
-
- /* A bit field may not span the unit of alignment of its type.
- Advance to next boundary if necessary. */
- /* ??? There is some uncertainty here as to what
- should be done if type_align is less than the width of the type.
- That can happen because the width exceeds BIGGEST_ALIGNMENT
- or because it exceeds maximum_field_alignment. */
- if (const_size / type_align
- != (const_size + field_size - 1) / type_align)
- const_size = CEIL (const_size, type_align) * type_align;
- }
- #endif
-
- /* No existing machine description uses this parameter.
- So I have made it in this aspect identical to PCC_BITFIELD_TYPE_MATTERS. */
- #ifdef BITFIELD_NBYTES_LIMITED
- if (BITFIELD_NBYTES_LIMITED
- && TREE_CODE (field) == FIELD_DECL
- && TREE_TYPE (field) != error_mark_node
- && DECL_BIT_FIELD_TYPE (field)
- && !DECL_PACKED (field)
- && !integer_zerop (DECL_SIZE (field)))
- {
- int type_align = TYPE_ALIGN (TREE_TYPE (field));
- register tree dsize = DECL_SIZE (field);
- int field_size = TREE_INT_CST_LOW (dsize);
-
- if (maximum_field_alignment != 0)
- type_align = MIN (type_align, maximum_field_alignment);
-
- /* A bit field may not span the unit of alignment of its type.
- Advance to next boundary if necessary. */
- if (const_size / type_align
- != (const_size + field_size - 1) / type_align)
- const_size = CEIL (const_size, type_align) * type_align;
- }
- #endif
-
- /* Size so far becomes the position of this field. */
-
- if (var_size && const_size)
- DECL_FIELD_BITPOS (field)
- = size_binop (PLUS_EXPR, var_size, size_int (const_size));
- else if (var_size)
- DECL_FIELD_BITPOS (field) = var_size;
- else
- DECL_FIELD_BITPOS (field) = size_int (const_size);
-
- /* If this field is an anonymous union,
- give each union-member the same position as the union has. */
-
- if (DECL_NAME (field) == 0
- && TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
- {
- tree uelt = TYPE_FIELDS (TREE_TYPE (field));
- for (; uelt; uelt = TREE_CHAIN (uelt))
- {
- DECL_FIELD_CONTEXT (uelt) = DECL_FIELD_CONTEXT (field);
- DECL_FIELD_BITPOS (uelt) = DECL_FIELD_BITPOS (field);
- }
- }
-
- /* Now add size of this field to the size of the record. */
-
- {
- register tree dsize = DECL_SIZE (field);
-
- /* This can happen when we have an invalid nested struct definition,
- such as struct j { struct j { int i; } }. The error message is
- printed in finish_struct. */
- if (dsize == 0)
- /* Do nothing. */;
- else if (TREE_CODE (dsize) == INTEGER_CST)
- const_size += TREE_INT_CST_LOW (dsize);
- else
- {
- if (var_size == 0)
- var_size = dsize;
- else
- var_size = size_binop (PLUS_EXPR, var_size, dsize);
- }
- }
- }
-
- /* Work out the total size and alignment of the record
- as one expression and store in the record type.
- Round it up to a multiple of the record's alignment. */
-
- if (var_size == 0)
- {
- TYPE_SIZE (rec) = size_int (const_size);
- }
- else
- {
- if (const_size)
- var_size
- = size_binop (PLUS_EXPR, var_size, size_int (const_size));
- TYPE_SIZE (rec) = var_size;
- }
-
- /* Determine the desired alignment. */
- #ifdef ROUND_TYPE_ALIGN
- TYPE_ALIGN (rec) = ROUND_TYPE_ALIGN (rec, TYPE_ALIGN (rec), record_align);
- #else
- TYPE_ALIGN (rec) = MAX (TYPE_ALIGN (rec), record_align);
- #endif
-
- #ifdef ROUND_TYPE_SIZE
- TYPE_SIZE (rec) = ROUND_TYPE_SIZE (rec, TYPE_SIZE (rec), TYPE_ALIGN (rec));
- #else
- /* Round the size up to be a multiple of the required alignment */
- TYPE_SIZE (rec) = round_up (TYPE_SIZE (rec), TYPE_ALIGN (rec));
- #endif
-
- return pending_statics;
- }
-
- /* Lay out a UNION_TYPE type.
- Lay out all the fields, set their positions to zero,
- and compute the size and alignment of the union (maximum of any field).
- Note that if you set the TYPE_ALIGN before calling this
- then the union align is aligned to at least that boundary. */
-
- static void
- layout_union (rec)
- tree rec;
- {
- register tree field;
- #ifdef STRUCTURE_SIZE_BOUNDARY
- unsigned union_align = STRUCTURE_SIZE_BOUNDARY;
- #else
- unsigned union_align = BITS_PER_UNIT;
- #endif
-
- /* The size of the union, based on the fields scanned so far,
- is max (CONST_SIZE, VAR_SIZE).
- VAR_SIZE may be null; then CONST_SIZE by itself is the size. */
- register int const_size = 0;
- register tree var_size = 0;
-
- for (field = TYPE_FIELDS (rec); field; field = TREE_CHAIN (field))
- {
- /* Enums which are local to this class need not be laid out. */
- if (TREE_CODE (field) == CONST_DECL || TREE_CODE (field) == TYPE_DECL)
- continue;
-
- layout_decl (field, 0);
- DECL_FIELD_BITPOS (field) = size_int (0);
-
- /* Union must be at least as aligned as any field requires. */
-
- union_align = MAX (union_align, DECL_ALIGN (field));
-
- #ifdef PCC_BITFIELD_TYPE_MATTERS
- /* On the m88000, a bit field of declare type `int'
- forces the entire union to have `int' alignment. */
- if (PCC_BITFIELD_TYPE_MATTERS && DECL_BIT_FIELD_TYPE (field))
- union_align = MAX (union_align, TYPE_ALIGN (TREE_TYPE (field)));
- #endif
-
- /* Set union_size to max (decl_size, union_size).
- There are more and less general ways to do this.
- Use only CONST_SIZE unless forced to use VAR_SIZE. */
-
- if (TREE_CODE (DECL_SIZE (field)) == INTEGER_CST)
- const_size = MAX (const_size, TREE_INT_CST_LOW (DECL_SIZE (field)));
- else if (var_size == 0)
- var_size = DECL_SIZE (field);
- else
- var_size = size_binop (MAX_EXPR, var_size, DECL_SIZE (field));
- }
-
- /* Determine the ultimate size of the union (in bytes). */
- if (NULL == var_size)
- TYPE_SIZE (rec) = size_int (CEIL (const_size, BITS_PER_UNIT)
- * BITS_PER_UNIT);
- else if (const_size == 0)
- TYPE_SIZE (rec) = var_size;
- else
- TYPE_SIZE (rec) = size_binop (MAX_EXPR, var_size,
- round_up (size_int (const_size),
- BITS_PER_UNIT));
-
- /* Determine the desired alignment. */
- #ifdef ROUND_TYPE_ALIGN
- TYPE_ALIGN (rec) = ROUND_TYPE_ALIGN (rec, TYPE_ALIGN (rec), union_align);
- #else
- TYPE_ALIGN (rec) = MAX (TYPE_ALIGN (rec), union_align);
- #endif
-
- #ifdef ROUND_TYPE_SIZE
- TYPE_SIZE (rec) = ROUND_TYPE_SIZE (rec, TYPE_SIZE (rec), TYPE_ALIGN (rec));
- #else
- /* Round the size up to be a multiple of the required alignment */
- TYPE_SIZE (rec) = round_up (TYPE_SIZE (rec), TYPE_ALIGN (rec));
- #endif
- }
-
- /* Calculate the mode, size, and alignment for TYPE.
- For an array type, calculate the element separation as well.
- Record TYPE on the chain of permanent or temporary types
- so that dbxout will find out about it.
-
- TYPE_SIZE of a type is nonzero if the type has been laid out already.
- layout_type does nothing on such a type.
-
- If the type is incomplete, its TYPE_SIZE remains zero. */
-
- void
- layout_type (type)
- tree type;
- {
- int old;
- tree pending_statics;
-
- if (type == 0)
- abort ();
-
- /* Do nothing if type has been laid out before. */
- if (TYPE_SIZE (type))
- return;
-
- /* Make sure all nodes we allocate are not momentary;
- they must last past the current statement. */
- old = suspend_momentary ();
-
- /* If we are processing a permanent type, make nodes permanent.
- If processing a temporary type, make it saveable, since the
- type node itself is. This is important if the function is inline,
- since its decls will get copied later. */
- push_obstacks_nochange ();
- if (allocation_temporary_p ())
- {
- if (TREE_PERMANENT (type))
- end_temporary_allocation ();
- else
- saveable_allocation ();
- }
-
- switch (TREE_CODE (type))
- {
- case LANG_TYPE:
- /* This kind of type is the responsibility
- of the languge-specific code. */
- abort ();
-
- case INTEGER_TYPE:
- case ENUMERAL_TYPE:
- if (TREE_INT_CST_HIGH (TYPE_MIN_VALUE (type)) >= 0)
- TREE_UNSIGNED (type) = 1;
-
- /* We pass 0 for the last arg of mode_for_size because otherwise
- on the Apollo using long long causes a crash.
- It seems better to use integer modes than to try to support
- integer types with BLKmode. */
- TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_INT, 0);
- TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
- break;
-
- case REAL_TYPE:
- TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
- TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
- break;
-
- case COMPLEX_TYPE:
- TREE_UNSIGNED (type) = TREE_UNSIGNED (TREE_TYPE (type));
- TYPE_MODE (type)
- = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
- (TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE
- ? MODE_COMPLEX_INT : MODE_COMPLEX_FLOAT),
- 0);
- TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
- break;
-
- case VOID_TYPE:
- TYPE_SIZE (type) = size_zero_node;
- TYPE_ALIGN (type) = 1;
- TYPE_MODE (type) = VOIDmode;
- break;
-
- case OFFSET_TYPE:
- TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (Pmode));
- TYPE_MODE (type) = Pmode;
- break;
-
- case FUNCTION_TYPE:
- case METHOD_TYPE:
- TYPE_MODE (type) = mode_for_size (2 * GET_MODE_BITSIZE (Pmode),
- MODE_INT, 0);
- TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
- break;
-
- case POINTER_TYPE:
- case REFERENCE_TYPE:
- TYPE_MODE (type) = Pmode;
- TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
- TREE_UNSIGNED (type) = 1;
- TYPE_PRECISION (type) = GET_MODE_BITSIZE (TYPE_MODE (type));
- break;
-
- case ARRAY_TYPE:
- {
- register tree index = TYPE_DOMAIN (type);
- register tree element = TREE_TYPE (type);
-
- build_pointer_type (element);
-
- /* We need to know both bounds in order to compute the size. */
- if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
- && TYPE_SIZE (element))
- {
- tree length
- = size_binop (PLUS_EXPR, size_one_node,
- size_binop (MINUS_EXPR, TYPE_MAX_VALUE (index),
- TYPE_MIN_VALUE (index)));
-
- TYPE_SIZE (type) = size_binop (MULT_EXPR, length,
- TYPE_SIZE (element));
- }
-
- /* Now round the alignment and size,
- using machine-dependent criteria if any. */
-
- #ifdef ROUND_TYPE_ALIGN
- TYPE_ALIGN (type)
- = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
- #else
- TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
- #endif
-
- #ifdef ROUND_TYPE_SIZE
- if (TYPE_SIZE (type) != 0)
- TYPE_SIZE (type)
- = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
- #endif
-
- TYPE_MODE (type) = BLKmode;
- if (TYPE_SIZE (type) != 0
- && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
- /* 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_INT_CST_LOW (TYPE_SIZE (type)),
- MODE_INT, 1);
-
- if (STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
- && TYPE_ALIGN (type) < TREE_INT_CST_LOW (TYPE_SIZE (type))
- && TYPE_MODE (type) != BLKmode)
- {
- TYPE_NO_FORCE_BLK (type) = 1;
- TYPE_MODE (type) = BLKmode;
- }
- }
- break;
- }
-
- case RECORD_TYPE:
- pending_statics = layout_record (type);
- TYPE_MODE (type) = BLKmode;
- if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
- {
- tree field;
- /* A record which has any BLKmode members must itself be BLKmode;
- it can't go in a register.
- Unless the member is BLKmode only because it isn't aligned. */
- for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
- {
- int bitpos;
-
- if (TREE_CODE (field) != FIELD_DECL)
- continue;
-
- if (TYPE_MODE (TREE_TYPE (field)) == BLKmode
- && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
- goto record_lose;
-
- if (TREE_CODE (DECL_FIELD_BITPOS (field)) != INTEGER_CST)
- goto record_lose;
-
- bitpos = TREE_INT_CST_LOW (DECL_FIELD_BITPOS (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
- != ((TREE_INT_CST_LOW (DECL_SIZE (field)) + bitpos - 1)
- / BITS_PER_WORD)
- /* But there is no problem if the field is entire words. */
- && TREE_INT_CST_LOW (DECL_SIZE (field)) % BITS_PER_WORD == 0)
- goto record_lose;
- }
-
- TYPE_MODE (type)
- = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
- MODE_INT, 1);
-
- /* If structure's known alignment is less than
- what the scalar mode would need, and it matters,
- then stick with BLKmode. */
- if (STRICT_ALIGNMENT
- && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
- || (TYPE_ALIGN (type)
- >= TREE_INT_CST_LOW (TYPE_SIZE (type)))))
- {
- if (TYPE_MODE (type) != BLKmode)
- /* If this is the only reason this type is BLKmode,
- then don't force containing types to be BLKmode. */
- TYPE_NO_FORCE_BLK (type) = 1;
- TYPE_MODE (type) = BLKmode;
- }
-
- record_lose: ;
- }
-
- /* Lay out any static members. This is done now
- because their type may use the record's type. */
- while (pending_statics)
- {
- layout_decl (TREE_VALUE (pending_statics), 0);
- pending_statics = TREE_CHAIN (pending_statics);
- }
- break;
-
- case UNION_TYPE:
- layout_union (type);
- TYPE_MODE (type) = BLKmode;
- if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
- /* If structure's known alignment is less than
- what the scalar mode would need, and it matters,
- then stick with BLKmode. */
- && (! STRICT_ALIGNMENT
- || TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
- || TYPE_ALIGN (type) >= TREE_INT_CST_LOW (TYPE_SIZE (type))))
- {
- tree field;
- /* A union which has any BLKmode members must itself be BLKmode;
- it can't go in a register.
- Unless the member is BLKmode only because it isn't aligned. */
- for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
- {
- if (TREE_CODE (field) != FIELD_DECL)
- continue;
-
- if (TYPE_MODE (TREE_TYPE (field)) == BLKmode
- && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
- goto union_lose;
- }
-
- TYPE_MODE (type)
- = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
- MODE_INT, 1);
-
- union_lose: ;
- }
- break;
-
- /* Pascal types */
- case BOOLEAN_TYPE: /* store one byte/boolean for now. */
- TYPE_MODE (type) = QImode;
- TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
- TYPE_PRECISION (type) = 1;
- TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
- break;
-
- case CHAR_TYPE:
- TYPE_MODE (type) = QImode;
- TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
- TYPE_PRECISION (type) = GET_MODE_BITSIZE (TYPE_MODE (type));
- TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
- 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_MODE (type) = BLKmode;
- break;
-
- default:
- abort ();
- } /* end switch */
-
- /* Normally, use the alignment corresponding to the mode chosen.
- However, where strict alignment is not required, avoid
- over-aligning structures, since most compilers do not do this
- alignment. */
-
- if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
- && (STRICT_ALIGNMENT
- || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
- && TREE_CODE (type) != ARRAY_TYPE)))
- TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
-
- /* Evaluate nonconstant size only once, either now or as soon as safe. */
- if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
- TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
-
- /* Also layout any other variants of the type. */
- if (TYPE_NEXT_VARIANT (type)
- || type != TYPE_MAIN_VARIANT (type))
- {
- tree variant;
- /* Record layout info of this variant. */
- tree size = TYPE_SIZE (type);
- int align = TYPE_ALIGN (type);
- enum machine_mode mode = TYPE_MODE (type);
-
- /* Copy it into all variants. */
- for (variant = TYPE_MAIN_VARIANT (type);
- variant;
- variant = TYPE_NEXT_VARIANT (variant))
- {
- TYPE_SIZE (variant) = size;
- TYPE_ALIGN (variant) = align;
- TYPE_MODE (variant) = mode;
- }
- }
-
- pop_obstacks ();
- resume_momentary (old);
- }
-
- /* Create and return a type for signed integers of PRECISION bits. */
-
- tree
- make_signed_type (precision)
- int precision;
- {
- register tree type = make_node (INTEGER_TYPE);
-
- TYPE_PRECISION (type) = precision;
-
- /* Create the extreme values based on the number of bits. */
-
- TYPE_MIN_VALUE (type)
- = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
- ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
- (((HOST_WIDE_INT) (-1)
- << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
- ? precision-HOST_BITS_PER_WIDE_INT - 1
- : 0))));
- TYPE_MAX_VALUE (type)
- = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
- ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
- (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
- ? (((HOST_WIDE_INT) 1
- << (precision - HOST_BITS_PER_INT - 1)))-1
- : 0));
-
- /* Give this type's extreme values this type as their type. */
-
- TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
- TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
-
- /* The first type made with this or `make_unsigned_type'
- is the type for size values. */
-
- if (sizetype == 0)
- {
- sizetype = type;
- }
-
- /* Lay out the type: set its alignment, size, etc. */
-
- layout_type (type);
-
- return type;
- }
-
- /* Create and return a type for unsigned integers of PRECISION bits. */
-
- tree
- make_unsigned_type (precision)
- int precision;
- {
- register tree type = make_node (INTEGER_TYPE);
-
- TYPE_PRECISION (type) = precision;
-
- /* The first type made with this or `make_signed_type'
- is the type for size values. */
-
- if (sizetype == 0)
- {
- sizetype = type;
- }
-
- fixup_unsigned_type (type);
- return type;
- }
-
- /* Set the extreme values of TYPE based on its precision in bits,
- the lay it out. Used when make_signed_type won't do
- because the tree code is not INTEGER_TYPE.
- E.g. for Pascal, when the -fsigned-char option is given. */
-
- void
- fixup_signed_type (type)
- tree type;
- {
- register int precision = TYPE_PRECISION (type);
-
- TYPE_MIN_VALUE (type)
- = build_int_2 ((precision-BITS_PER_WORD > 0 ? 0 : (-1)<<(precision-1)),
- (-1)<<(precision-BITS_PER_WORD-1 > 0
- ? precision-BITS_PER_WORD-1
- : 0));
- TYPE_MAX_VALUE (type)
- = build_int_2 ((precision-BITS_PER_WORD > 0 ? -1 : (1<<(precision-1))-1),
- (precision-BITS_PER_WORD-1 > 0
- ? (1<<(precision-BITS_PER_WORD-1))-1
- : 0));
-
- TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
- TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
-
- /* Lay out the type: set its alignment, size, etc. */
-
- layout_type (type);
- }
-
- /* Set the extreme values of TYPE based on its precision in bits,
- the lay it out. This is used both in `make_unsigned_type'
- and for enumeral types. */
-
- void
- fixup_unsigned_type (type)
- tree type;
- {
- register int precision = TYPE_PRECISION (type);
-
- TYPE_MIN_VALUE (type) = build_int_2 (0, 0);
- TYPE_MAX_VALUE (type)
- = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
- ? -1 : ((HOST_WIDE_INT) 1<< precision) - 1,
- precision - HOST_BITS_PER_WIDE_INT > 0
- ? ((unsigned HOST_WIDE_INT) ~0
- >> (HOST_BITS_PER_WIDE_INT
- - (precision - HOST_BITS_PER_WIDE_INT)))
- : 0);
- TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
- TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
-
- /* Lay out the type: set its alignment, size, etc. */
-
- layout_type (type);
- }
-
- /* Find the best machine mode to use when referencing a bit field of length
- BITSIZE bits starting at BITPOS.
-
- The underlying object is known to be aligned to a boundary of ALIGN bits.
- If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
- larger than LARGEST_MODE (usually SImode).
-
- If no mode meets all these conditions, we return VOIDmode. Otherwise, if
- VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
- mode meeting these conditions.
-
- Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
- the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
- all the conditions. */
-
- enum machine_mode
- get_best_mode (bitsize, bitpos, align, largest_mode, volatilep)
- int bitsize, bitpos;
- int align;
- enum machine_mode largest_mode;
- int volatilep;
- {
- enum machine_mode mode;
- int unit;
-
- /* Find the narrowest integer mode that contains the bit field. */
- for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
- mode = GET_MODE_WIDER_MODE (mode))
- {
- unit = GET_MODE_BITSIZE (mode);
- if (bitpos / unit == (bitpos + bitsize - 1) / unit)
- break;
- }
-
- if (mode == MAX_MACHINE_MODE
- /* It is tempting to omit the following line
- if STRICT_ALIGNMENT is true.
- But that is incorrect, since if the bitfield uses part of 3 bytes
- and we use a 4-byte mode, we could get a spurious segv
- if the extra 4th byte is past the end of memory.
- (Though at least one Unix compiler ignores this problem:
- that on the Sequent 386 machine. */
- || MIN (unit, BIGGEST_ALIGNMENT) > align
- || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
- return VOIDmode;
-
- if (SLOW_BYTE_ACCESS && ! volatilep)
- {
- enum machine_mode wide_mode = VOIDmode, tmode;
-
- for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
- tmode = GET_MODE_WIDER_MODE (tmode))
- {
- unit = GET_MODE_BITSIZE (tmode);
- if (bitpos / unit == (bitpos + bitsize - 1) / unit
- && unit <= BITS_PER_WORD
- && unit <= MIN (align, BIGGEST_ALIGNMENT)
- && (largest_mode == VOIDmode
- || unit <= GET_MODE_BITSIZE (largest_mode)))
- wide_mode = tmode;
- }
-
- if (wide_mode != VOIDmode)
- return wide_mode;
- }
-
- return mode;
- }
-
- /* Save all variables describing the current status into the structure *P.
- This is used before starting a nested function. */
-
- void
- save_storage_status (p)
- struct function *p;
- {
- #if 0 /* Need not save, since always 0 and non0 (resp.) within a function. */
- p->pending_sizes = pending_sizes;
- p->immediate_size_expand = immediate_size_expand;
- #endif /* 0 */
- }
-
- /* Restore all variables describing the current status from the structure *P.
- This is used after a nested function. */
-
- void
- restore_storage_status (p)
- struct function *p;
- {
- #if 0
- pending_sizes = p->pending_sizes;
- immediate_size_expand = p->immediate_size_expand;
- #endif /* 0 */
- }
-