src/: Stuff vtable structures into a union.

[sod] / src / class-output.lisp

diff --git a/src/class-output.lisp b/src/class-output.lisp
index 2ab6363..eb5bc26 100644 (file)
--- a/src/class-output.lisp
+++ b/src/class-output.lisp
@@ -296,11 +296,23 @@
                         struct ~A {~%"
                 (vtable-struct-tag chain-tail chain-head)))
        ((class :vtable chain-head :end)
-        (format stream "};~2%"))))
+        (format stream "};~2%")
+        (format stream "/* Union of equivalent superclass vtables. */~@
+                        union ~A {~@
+                        ~:{  struct ~A ~A;~%~}~
+                        };~2%"
+                (vtable-union-tag chain-tail chain-head)
+
+                ;; As for the ichain union, make sure the most specific
+                ;; class is first.
+                (mapcar (lambda (super)
+                          (list (vtable-struct-tag super chain-head)
+                                (sod-class-nickname super)))
+                        (sod-class-chain chain-tail))))))
     (sequence-output (stream sequencer)
       ((class :vtable-externs)
-       (format stream "~@<extern const struct ~A ~2I~_~A__vtable_~A;~:>~%"
-              (vtable-struct-tag chain-tail chain-head)
+       (format stream "~@<extern const union ~A ~2I~_~A__vtable_~A;~:>~%"
+              (vtable-union-tag chain-tail chain-head)
               class (sod-class-nickname chain-head))))))
 
 (defmethod hook-output progn ((vtmsgs vtmsgs) (reason (eql :h)) sequencer)
@@ -470,12 +482,12 @@ const struct ~A ~A__classobj = {~%"
                   (class :vtables :end))
       ((class :vtable chain-head :start)
        (format stream "/* Vtable for ~A chain. */~@
-                      const struct ~A ~A = {~%"
+                      const union ~A ~A = { {~%"
               chain-head
-              (vtable-struct-tag chain-tail chain-head)
+              (vtable-union-tag chain-tail chain-head)
               (vtable-name class chain-head)))
       ((class :vtable chain-head :end)
-       (format stream "};~2%")))))
+       (format stream "} };~2%")))))
 
 (defmethod hook-output progn ((cptr class-pointer)
                              (reason (eql :c))
@@ -592,8 +604,10 @@ const struct ~A ~A__classobj = {~%"
                   (*instance-class* :object chain-head :vtable)
                   (*instance-class* :object chain-head :ichain :end))
       ((*instance-class* :object chain-head :vtable)
-       (format stream "      &~A__vtable_~A,~%"
-              class (sod-class-nickname chain-head))))))
+       (format stream "      /* ~17@A = */ &~A.~A,~%"
+              "_vt"
+              (vtable-name class chain-head)
+              (sod-class-nickname chain-tail))))))
 
 (defgeneric find-class-initializer (slot class)
   (:method ((slot effective-slot) (class sod-class))