stor-layout.c (layout_decl): Allow front-ends to explicitly set the DECL_SIZE for a FIELD_DECL.

* stor-layout.c (layout_decl): Allow front-ends to explicitly set
	the DECL_SIZE for a FIELD_DECL.

From-SVN: r32287
This commit is contained in:
Mark Mitchell 2000-03-01 22:29:56 +00:00 committed by Mark Mitchell
parent 647639eff7
commit 33433751ff
3 changed files with 46 additions and 21 deletions

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@ -1,3 +1,8 @@
2000-03-01 Mark Mitchell <mark@codesourcery.com>
* stor-layout.c (layout_decl): Allow front-ends to explicitly set
the DECL_SIZE for a FIELD_DECL.
2000-03-01 Bruce Korb <bkorb@gnu.org>
* fixinc/inclhack.tpl: remove unused symlinks

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@ -265,30 +265,17 @@ layout_decl (decl, known_align)
{
register tree type = TREE_TYPE (decl);
register enum tree_code code = TREE_CODE (decl);
HOST_WIDE_INT spec_size = 0;
if (code == CONST_DECL)
return;
else if (code == FIELD_DECL)
{
if (DECL_SIZE (decl) != 0)
{
spec_size = TREE_INT_CST_LOW (DECL_SIZE (decl));
DECL_SIZE (decl) = 0;
}
}
else if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
&& code != TYPE_DECL)
&& code != TYPE_DECL && code != FIELD_DECL)
abort ();
if (type == error_mark_node)
{
type = void_type_node;
spec_size = 0;
}
type = void_type_node;
/* Usually the size and mode come from the data type without change. */
DECL_MODE (decl) = TYPE_MODE (type);
TREE_UNSIGNED (decl) = TREE_UNSIGNED (type);
if (DECL_SIZE (decl) == 0)
@ -296,14 +283,23 @@ layout_decl (decl, known_align)
DECL_SIZE (decl) = TYPE_SIZE (type);
DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
}
if (code == FIELD_DECL && DECL_BIT_FIELD (decl))
else if (code == FIELD_DECL)
{
if (spec_size == 0 && DECL_NAME (decl) != 0)
HOST_WIDE_INT spec_size;
/* The front-end may set the explicit width of the field, so its
size may not be the same as the size of its type. This happens
with bitfields, of course (an `int' bitfield may be only 2 bits,
say), but it also happens with other fields. For example, the
C++ front-end creates zero-sized fields corresponding to empty
base classes, and depends on layout_type setting
DECL_FIELD_BITPOS correctly for the field. */
if (integer_zerop (DECL_SIZE (decl))
&& DECL_NAME (decl) != NULL_TREE)
abort ();
/* Size is specified in number of bits. */
DECL_SIZE (decl) = bitsize_int (spec_size);
spec_size = TREE_INT_CST_LOW (DECL_SIZE (decl));
if (spec_size % BITS_PER_UNIT == 0)
DECL_SIZE_UNIT (decl) = size_int (spec_size / BITS_PER_UNIT);
else
@ -313,8 +309,9 @@ layout_decl (decl, known_align)
/* 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)))
if (!(code == FIELD_DECL && DECL_BIT_FIELD (decl))
&& (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.

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@ -0,0 +1,23 @@
// Build don't link:
// Special g++ Options: -fnew-abi
// Origin: Mark Mitchell <mark@codesourcery.com>
struct S
{
};
struct T : public S
{
};
struct U : public T
{
};
void f (U);
int main ()
{
U u;
f (u);
}