Avoid having "guild compile" load optimizers

* module/language/cps/optimize.scm (cps-optimizations):
* module/language/tree-il/optimize.scm (tree-il-optimizations):
* module/system/base/optimize.scm (available-optimizations): Invert the
  dependency tree to hold the names and default optimization levels in a
  central place instead of in the optimizers.  It moves definitions
  farther from uses, but it avoids us having to load the CPS optimizer
  if we don't need it, which improves bootstrap times.

module/language/cps/optimize.scm

@@ -42,6 +42,7 @@
   #:use-module (language cps split-rec)
   #:use-module (language cps type-fold)
   #:use-module (language cps verify)
+  #:use-module (system base optimize)
   #:export (optimize-higher-order-cps
             optimize-first-order-cps
             cps-optimizations
@@ -117,22 +118,7 @@
   (simplify #:simplify? #t))
 
 (define (cps-optimizations)
-  '( ;; (#:split-rec? #t)
-    (#:simplify? 2)
-    (#:eliminate-dead-code? 2)
-    (#:prune-top-level-scopes? 2)
-    (#:contify? 2)
-    (#:specialize-primcalls? 2)
-    (#:peel-loops? 2)
-    (#:cse? 2)
-    (#:type-fold? 2)
-    (#:resolve-self-references? 2)
-    (#:devirtualize-integers? 2)
-    (#:specialize-numbers? 2)
-    (#:licm? 2)
-    (#:rotate-loops? 2)
-    ;; This one is used by the slot allocator.
-    (#:precolor-calls? 2)))
+  (available-optimizations 'cps))
 
 (define (lower-cps exp opts)
   ;; FIXME: For now the closure conversion pass relies on $rec instances

module/language/tree-il/optimize.scm

@@ -27,6 +27,7 @@
   #:use-module (language tree-il peval)
   #:use-module (language tree-il primitives)
   #:use-module (ice-9 match)
+  #:use-module (system base optimize)
   #:export (optimize
             make-lowerer
             tree-il-optimizations))
@@ -62,21 +63,7 @@
   x)
 
 (define (tree-il-optimizations)
-  ;; Avoid resolve-primitives until -O2, when CPS optimizations kick in.
-  ;; Otherwise, inlining the primcalls during Tree-IL->CPS compilation
-  ;; will result in a lot of code that will never get optimized nicely.
-  ;; Similarly letrectification is great for generated code quality, but
-  ;; as it gives the compiler more to work with, it increases compile
-  ;; time enough that we reserve it for -O2.  Also, this makes -O1 avoid
-  ;; assumptions about top-level values, in the same way that avoiding
-  ;; resolve-primitives does.
-  '((#:cps? 1)
-    (#:resolve-primitives? 2)
-    (#:expand-primitives? 1)
-    (#:letrectify? 2)
-    (#:seal-private-bindings? 3)
-    (#:partial-eval? 1)
-    (#:eta-expand? 2)))
+  (available-optimizations 'tree-il))
 
 (define (make-lowerer optimization-level opts)
   (define (enabled-for-level? level) (<= level optimization-level))

module/system/base/optimize.scm

@@ -1,6 +1,6 @@
 ;;; Optimization flags
 
-;; Copyright (C) 2018 Free Software Foundation, Inc.
+;; Copyright (C) 2018, 2020 Free Software Foundation, Inc.
 
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -19,15 +19,49 @@
 ;;; Code:
 
 (define-module (system base optimize)
-  #:use-module (language tree-il optimize)
-  #:use-module (language cps optimize)
   #:use-module (ice-9 match)
   #:export (available-optimizations
             pass-optimization-level
             optimizations-for-level))
 
-(define (available-optimizations)
-  (append (tree-il-optimizations) (cps-optimizations)))
+(define* (available-optimizations #:optional lang-name)
+  (match lang-name
+    ('tree-il
+     ;; Avoid resolve-primitives until -O2, when CPS optimizations kick in.
+     ;; Otherwise, inlining the primcalls during Tree-IL->CPS compilation
+     ;; will result in a lot of code that will never get optimized nicely.
+     ;; Similarly letrectification is great for generated code quality, but
+     ;; as it gives the compiler more to work with, it increases compile
+     ;; time enough that we reserve it for -O2.  Also, this makes -O1 avoid
+     ;; assumptions about top-level values, in the same way that avoiding
+     ;; resolve-primitives does.
+     '((#:cps? 1)
+       (#:resolve-primitives? 2)
+       (#:expand-primitives? 1)
+       (#:letrectify? 2)
+       (#:seal-private-bindings? 3)
+       (#:partial-eval? 1)
+       (#:eta-expand? 2)))
+    ('cps
+     '( ;; (#:split-rec? #t)
+       (#:simplify? 2)
+       (#:eliminate-dead-code? 2)
+       (#:prune-top-level-scopes? 2)
+       (#:contify? 2)
+       (#:specialize-primcalls? 2)
+       (#:peel-loops? 2)
+       (#:cse? 2)
+       (#:type-fold? 2)
+       (#:resolve-self-references? 2)
+       (#:devirtualize-integers? 2)
+       (#:specialize-numbers? 2)
+       (#:licm? 2)
+       (#:rotate-loops? 2)
+       ;; This one is used by the slot allocator.
+       (#:precolor-calls? 2)))
+    (#f
+     (append (available-optimizations 'tree-il)
+             (available-optimizations 'cps)))))
 
 (define (pass-optimization-level kw)
   (match (assq kw (available-optimizations))