bool *));
static tree handle_pure_attribute PARAMS ((tree *, tree, tree, int,
bool *));
+static tree handle_vector_size_attribute PARAMS ((tree *, tree, tree, int,
+ bool *));
+static tree vector_size_helper PARAMS ((tree, tree));
/* Table of machine-independent attributes common to all C-like languages. */
static const struct attribute_spec c_common_attribute_table[] =
handle_no_limit_stack_attribute },
{ "pure", 0, 0, true, false, false,
handle_pure_attribute },
+ { "vector_size", 1, 1, false, true, false,
+ handle_vector_size_attribute },
{ NULL, 0, 0, false, false, false, NULL }
};
returned_attrs = chainon ((*spec->handler) (anode, name, args,
flags, &no_add_attrs),
returned_attrs);
+
+ /* Layout the decl in case anything changed. */
+ if (spec->type_required && DECL_P (*node)
+ && TREE_CODE (*node) == VAR_DECL)
+ {
+ /* Force a recalculation of mode and size. */
+ DECL_MODE (*node) = VOIDmode;
+ DECL_SIZE (*node) = 0;
+
+ layout_decl (*node, 0);
+ }
+
if (!no_add_attrs)
{
tree old_attrs;
return NULL_TREE;
}
+/* Handle a "vector_size" attribute; arguments as in
+ struct attribute_spec.handler. */
+
+static tree
+handle_vector_size_attribute (node, name, args, flags, no_add_attrs)
+ tree *node;
+ tree name;
+ tree args;
+ int flags ATTRIBUTE_UNUSED;
+ bool *no_add_attrs;
+{
+ unsigned int vecsize, nunits;
+ enum machine_mode mode, orig_mode, new_mode;
+ tree type = *node, new_type;
+
+ *no_add_attrs = true;
+
+ if (TREE_CODE (TREE_VALUE (args)) != INTEGER_CST)
+ {
+ warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
+ return NULL_TREE;
+ }
+
+ /* Get the vector size (in bytes). */
+ vecsize = TREE_INT_CST_LOW (TREE_VALUE (args));
+
+ /* We need to provide for vector pointers, vector arrays, and
+ functions returning vectors. For example:
+
+ __attribute__((vector_size(16))) short *foo;
+
+ In this case, the mode is SI, but the type being modified is
+ HI, so we need to look further. */
+
+ while (POINTER_TYPE_P (type)
+ || TREE_CODE (type) == FUNCTION_TYPE
+ || TREE_CODE (type) == ARRAY_TYPE)
+ type = TREE_TYPE (type);
+
+ /* Get the mode of the type being modified. */
+ orig_mode = TYPE_MODE (type);
+
+ if (TREE_CODE (type) == RECORD_TYPE ||
+ (GET_MODE_CLASS (orig_mode) != MODE_FLOAT
+ && GET_MODE_CLASS (orig_mode) != MODE_INT))
+ {
+ error ("invalid vector type for attribute `%s'",
+ IDENTIFIER_POINTER (name));
+ return NULL_TREE;
+ }
+
+ /* Calculate how many units fit in the vector. */
+ nunits = vecsize / TREE_INT_CST_LOW (TYPE_SIZE_UNIT (type));
+
+ /* Find a suitably sized vector. */
+ new_mode = VOIDmode;
+ for (mode = GET_CLASS_NARROWEST_MODE (GET_MODE_CLASS (orig_mode) == MODE_INT
+ ? MODE_VECTOR_INT
+ : MODE_VECTOR_FLOAT);
+ mode != VOIDmode;
+ mode = GET_MODE_WIDER_MODE (mode))
+ if (vecsize == GET_MODE_SIZE (mode) && nunits == GET_MODE_NUNITS (mode))
+ {
+ new_mode = mode;
+ break;
+ }
+
+ if (new_mode == VOIDmode)
+ error ("no vector mode with the size and type specified could be found");
+ else
+ {
+ new_type = type_for_mode (new_mode, TREE_UNSIGNED (type));
+ if (!new_type)
+ error ("no vector mode with the size and type specified could be found");
+ else
+ /* Build back pointers if needed. */
+ *node = vector_size_helper (*node, new_type);
+ }
+
+ return NULL_TREE;
+}
+
+/* HACK. GROSS. This is absolutely disgusting. I wish there was a
+ better way.
+
+ If we requested a pointer to a vector, build up the pointers that
+ we stripped off while looking for the inner type. Similarly for
+ return values from functions.
+
+ The argument "type" is the top of the chain, and "bottom" is the
+ new type which we will point to. */
+
+static tree
+vector_size_helper (type, bottom)
+ tree type, bottom;
+{
+ tree inner, outer;
+
+ if (POINTER_TYPE_P (type))
+ {
+ inner = vector_size_helper (TREE_TYPE (type), bottom);
+ outer = build_pointer_type (inner);
+ }
+ else if (TREE_CODE (type) == ARRAY_TYPE)
+ {
+ inner = vector_size_helper (TREE_TYPE (type), bottom);
+ outer = build_array_type (inner, TYPE_VALUES (type));
+ }
+ else if (TREE_CODE (type) == FUNCTION_TYPE)
+ {
+ inner = vector_size_helper (TREE_TYPE (type), bottom);
+ outer = build_function_type (inner, TYPE_VALUES (type));
+ }
+ else
+ return bottom;
+
+ TREE_READONLY (outer) = TREE_READONLY (type);
+ TREE_THIS_VOLATILE (outer) = TREE_THIS_VOLATILE (type);
+
+ return outer;
+}
+
/* Split SPECS_ATTRS, a list of declspecs and prefix attributes, into two
lists. SPECS_ATTRS may also be just a typespec (eg: RECORD_TYPE).
The keyword @code{__attribute__} allows you to specify special
attributes of variables or structure fields. This keyword is followed
-by an attribute specification inside double parentheses. Eight
+by an attribute specification inside double parentheses. Nine
attributes are currently defined for variables: @code{aligned},
@code{mode}, @code{nocommon}, @code{packed}, @code{section},
-@code{transparent_union}, @code{unused}, and @code{weak}. Some other
-attributes are defined for variables on particular target systems. Other
-attributes are available for functions (@pxref{Function Attributes}) and
-for types (@pxref{Type Attributes}). Other front ends might define more
-attributes (@pxref{C++ Extensions,,Extensions to the C++ Language}).
+@code{transparent_union}, @code{unused}, @code{vector_size}, and
+@code{weak}. Some other attributes are defined for variables on
+particular target systems. Other attributes are available for functions
+(@pxref{Function Attributes}) and for types (@pxref{Type Attributes}).
+Other front ends might define more attributes (@pxref{C++
+Extensions,,Extensions to the C++ Language}).
You may also specify attributes with @samp{__} preceding and following
each keyword. This allows you to use them in header files without
to be possibly unused. GCC will not produce a warning for this
variable.
+@item vector_size (@var{bytes})
+This attribute specifies the vector size for the variable, measured in
+bytes. For example, the declaration:
+
+@smallexample
+int foo __attribute__ ((vector_size (16)));
+@end smallexample
+
+@noindent
+causes the compiler to set the mode for @code{foo}, to be 16 bytes,
+divided into @code{int} sized units. Assuming a 32-bit int (a vector of
+4 units of 4 bytes), the corresponding mode of @code{foo} will be V4SI@.
+
+This attribute is only applicable to integral and float scalars,
+although arrays, pointers, and function return values are allowed in
+conjunction with this construct.
+
+Aggregates with this attribute are invalid, even if they are of the same
+size as a corresponding scalar. For example, the declaration:
+
+@smallexample
+struct S { int a; };
+struct S __attribute__ ((vector_size (16))) foo;
+@end smallexample
+
+@noindent
+is invalid even if the size of the structure is the same as the size of
+the @code{int}.
+
@item weak
The @code{weak} attribute is described in @xref{Function Attributes}.
git://gcc.gnu.org / gcc.git / commitdiff