Changeset 14222

Timestamp:

Aug 26, 2010, 3:23:35 PM (9 years ago)

Author:

gb

Message:

Don't "naturally" align a record field if the field type's natural
alignment is greater than the word size (unless the ftd has a
:natural-alignment attribute.)

The ARM always aligns fields on natural boundaries; PPC32 and X8632
don't. (In other words, this has been wrong for years.)

If we ever support (SIMD) vector types, this'll have to be revisited.

Location:

trunk/source

Files:

• compiler/ARM/arm-backend.lisp (modified) (2 diffs)
• lib/foreign-types.lisp (modified) (2 diffs)

trunk/source/compiler/ARM/arm-backend.lisp

@@ -286 +286 @@
                                          :signed-char t
                                          :struct-by-value t
+                                         :natural-alignment t
                                          :prepend-underscore nil)
                            :ff-call-expand-function
@@ -301 +302 @@
                            :attributes '(:bits-per-word  32
                                          :signed-char nil
+                                         :natural-alignment t
                                          :struct-by-value t)
                            :ff-call-expand-function

trunk/source/lib/foreign-types.lisp

@@ -1095 +1095 @@
            (first-field-p t)
            (attributes (ftd-attributes *target-ftd*))
-           (poweropen-alignment (getf attributes :poweropen-alignment)))
-          
+           (poweropen-alignment (getf attributes :poweropen-alignment))
+           (bits-per-word (getf attributes :bits-per-word))
+           (use-natural-alignment (getf attributes :natural-alignment)))
+        
       (dolist (field fields)
         (destructuring-bind (var type &optional bits) field
@@ -1111 +1113 @@
                                     natural-alignment)
                                   (min 32 natural-alignment))
-                                natural-alignment)))
+                                (if use-natural-alignment
+                                  natural-alignment
+                                  (min bits-per-word natural-alignment)))))
                  (parsed-field
                   (make-foreign-record-field :type field-type