1.0.19.7: refactor stack allocation decisions

 * Remove SB-C::STACK-ALLOCATE-* policies.

 * Obey DYNAMIC-EXTENT declarations if SB-EXT:*STACK-ALLOCATE-DYNAMIC-EXTENT*
   is true (the default), with the following exceptions:

    ** Value cells are not stack allocated.

    ** Vectors that may be longer then a single page are stack
       allocated only in SAFETY 0 policies.

 * New declaration: SB-INT:TRULY-DYNAMIC-EXTENT. Always stack-allocates,
   regardless of SB-EXT:*STACK-ALLOCATE-DYNAMIC-EXTENT*. Also causes stack
   allocation of value cells and potentially large vectors.

   Used exclusively inside SBCL.

 * Move STACK-ALLOCATE-RESULT optimizers from backends to
   src/compiler/generic/vm-ir2tran.lisp.

 * Documentation.

BUGS

@@ -1805,27 +1805,26 @@ WORKAROUND:
 
 419: stack-allocated indirect closure variables are not popped
 
-    (locally (declare (optimize sb-c::stack-allocate-dynamic-extent
-                                sb-c::stack-allocate-value-cells))
       (defun bug419 (x)
         (multiple-value-call #'list
           (eval '(values 1 2 3))
           (let ((x x))
-            (declare (dynamic-extent x))
+            (declare (sb-int:truly-dynamic-extent x))
             (flet ((mget (y)
                      (+ x y))
                    (mset (z)
                      (incf x z)))
               (declare (dynamic-extent #'mget #'mset))
-              ((lambda (f g) (eval `(progn ,f ,g (values 4 5 6)))) #'mget #'mset))))))
+              ((lambda (f g) (eval `(progn ,f ,g (values 4 5 6)))) #'mget #'mset)))))
 
   (ASSERT (EQUAL (BUG419 42) '(1 2 3 4 5 6))) => failure
 
   Note: as of SBCL 1.0.26.29 this bug no longer affects user code, as
-  SB-C::STACK-ALLOCATE-VALUE-CELLS needs to be explicitly turned on for
-  that to happen. Proper fix for this bug requires (Nikodemus thinks)
-  storing the relevant LAMBDA-VARs in a :DYNAMIC-EXTENT cleanup, and
-  teaching stack analysis how to deal with them.
+  SB-INT:TRULY-DYNAMIC-EXTENT needs to be used instead of
+  DYNAMIC-EXTENT for this to happen. Proper fix for this bug requires
+  (Nikodemus thinks) storing the relevant LAMBDA-VARs in a
+  :DYNAMIC-EXTENT cleanup, and teaching stack analysis how to deal
+  with them.
 
 421: READ-CHAR-NO-HANG misbehaviour on Windows Console:
 

NEWS

@@ -1,5 +1,9 @@
 ;;;; -*- coding: utf-8; -*-
 changes in sbcl-1.0.20 relative to 1.0.19:
+  * minor incompatible change: OPTIMIZE qualities
+    SB-C::STACK-ALLOCATE-DYNAMIC-EXTENT, SB-C::STACK-ALLOCATE-VECTOR,
+    and SB-C::STACK-ALLOCATE-VALUE-CELLS no longer exist. See documentation
+    and SB-EXT:*STACK-ALLOCATE-DYNAMIC-EXTENT* for details.
   * bug fix: fixed #427: unused local aliens no longer cause compiler
     breakage. (reported by Stelian Ionescu, Andy Hefner and Stanislaw
     Halik)

build-order.lisp-expr

@@ -35,6 +35,7 @@
 (
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;; miscellaneous
+ ("src/code/cross-early" :not-target)
 
  ;; This comes early because it's useful for debugging everywhere.
  ("src/code/show")