Added unfortunate hack for introspection

Rather than setting the field-type-metadata in the initializer, set it
in an introspection runtime fixup function. This is necessary
especially when metadata references a type in another file. I'm not
happy with this, but I want to move forwards with my project that
depends on Introspection.

src/Introspection.cake

@@ -110,6 +110,13 @@
   (when (= -1 start-members)
     (return false))
 
+  (defstruct non-constant-field-data
+    field-metadata-struct-name Token
+    field-index int)
+  (var non-constant-fields (template (in std vector) non-constant-field-data))
+
+  (var field-index int 0)
+
   (each-token-argument-in tokens start-members end-token-index i
     (var name-token (addr (const Token))
       (addr (at i tokens)))
@@ -128,10 +135,10 @@
 
     (var tags-tokens (template (in std vector) Token))
     (call-on resize tags-tokens (introspect-get-num-tags))
-    (each-in-range (call-on size tags-tokens) i
-      (set (at i tags-tokens) (deref type-token))
-      (set (field (at i tags-tokens) type) TokenType_Symbol)
-      (set (field (at i tags-tokens) contents) "null"))
+    (each-in-range (call-on size tags-tokens) tag-index
+      (set (at tag-index tags-tokens) (deref type-token))
+      (set (field (at tag-index tags-tokens) type) TokenType_Symbol)
+      (set (field (at tag-index tags-tokens) contents) "null"))
     (var next-free-tag-token int 0)
 
     (when (= TokenType_OpenParen (path annotations-token > type))
@@ -242,7 +249,11 @@
         (introspect-metadata-pointer-name-from-struct-name
          type-metadata-pointer-name (sizeof type-metadata-pointer-name)
          (call-on c_str (path core-type-token > contents)))
-        (set (field field-type-metadata-token contents) type-metadata-pointer-name))
+        (set (field field-type-metadata-token contents) type-metadata-pointer-name)
+        (var new-non-const-field non-constant-field-data)
+        (set (field new-non-const-field field-metadata-struct-name) field-type-metadata-token)
+        (set (field new-non-const-field field-index) field-index)
+        (call-on push_back non-constant-fields new-non-const-field))
 
       (var field-count Token (deref core-type-token))
       (unless array-count-token
@@ -251,7 +262,10 @@
         (set array-count-token (addr field-count)))
 
       (var field-type-metadata-reference (template (in std vector) Token))
-      (if (call-on empty (field field-type-metadata-token contents))
+      ;; This used to output the type metadata struct pointer, but when fields reference types in
+      ;; other modules, that causes a non-const initializer, which is not allowed in C. Now, all
+      ;; metadata struct pointers will be set in introspect-initialize at runtime.
+      (if (or true (call-on empty (field field-type-metadata-token contents)))
           (tokenize-push field-type-metadata-reference null)
           (tokenize-push field-type-metadata-reference
             (token-splice-addr field-type-metadata-token)))
@@ -275,7 +289,8 @@
                (offsetof (type (token-splice struct-name)) (token-splice name-token))
                (token-splice-array field-type-element-size)
                (token-splice array-count-token)
-               (array (token-splice-array tags-tokens)))))
+               (array (token-splice-array tags-tokens))))
+      (incr field-index))
 
     ;; Output regular struct fields
     (PushBackTokenExpression (deref processed-arguments) name-token)
@@ -313,8 +328,13 @@
     (defstruct (token-splice struct-name)
       (token-splice-array (deref processed-arguments)))
 
-    (var (token-splice-addr metadata-fields-name) (const (array metadata-field))
-      (array (token-splice-array (deref fields-metadata))))
+    (forward-declare (struct metadata-field))
+    ;; This is a hidden global so Introspection.cake can access it, but no other modules should have
+    ;; easy access without the programmer going out of their way to expose it.
+    (var-hidden-global
+     (token-splice-addr metadata-fields-name)
+     (array metadata-field)
+     (array (token-splice-array (deref fields-metadata))))
     (var (token-splice-addr metadata-name) (const metadata-struct)
       (array (token-splice-addr struct-name-to-str)
              (token-splice-addr metadata-fields-name)
@@ -324,7 +344,25 @@
     ;; Allow access to the metadata without having to declare all the types in the header
     (forward-declare (struct metadata-struct)) ;; TODO Would be nice to not do this for every struct
     (var-global (token-splice-addr metadata-pointer-name) (const (addr (const metadata-struct)))
-                (addr (token-splice-addr metadata-name))))
+      (addr (token-splice-addr metadata-name))))
+
+  ;; Non-constant fields must be set at runtime
+  (unless (call-on empty non-constant-fields)
+    (get-or-create-comptime-var environment runtime-fixup (template (in std vector) Token))
+    (tokenize-push (deref runtime-fixup)
+      (declare-external (var (token-splice-addr metadata-fields-name) (array metadata-field))))
+    (each-in-range (call-on size non-constant-fields) non-const-field-index
+      (var non-const-field (addr non-constant-field-data)
+        (addr (at non-const-field-index non-constant-fields)))
+      (var field-index-token Token (path non-const-field > field-metadata-struct-name))
+      (token-contents-snprintf field-index-token "%d" (path non-const-field > field-index))
+      (tokenize-push (deref runtime-fixup)
+        (declare-external (var (token-splice-addr (path non-const-field > field-metadata-struct-name))
+                              (addr (const metadata-struct))))
+        (set (field (at (token-splice-addr field-index-token) (token-splice-addr metadata-fields-name))
+                    field-type-metadata)
+             (token-splice-addr (path non-const-field > field-metadata-struct-name))))))
+
   (return true))
 
 ;; TODO: This is a limitation of not being able to declare and reference new types in comptime
@@ -704,6 +742,58 @@
 
 (add-compile-time-hook post-references-resolved introspect-overrides-install)
 
+(defun introspect-fixup-runtime-pointers ())
+
+(defmacro introspect-initialize ()
+  (get-or-create-comptime-var environment introspect-initialize-called bool false)
+  (set (deref introspect-initialize-called) true)
+  (tokenize-push output (introspect-fixup-runtime-pointers))
+  (return true))
+
+(defun-comptime introspect-runtime-fixup-install (environment (ref EvaluatorEnvironment)
+                                                  &return bool)
+  ;; TODO: Validate the user calls the fixup function much like data-bundle
+  (get-or-create-comptime-var environment runtime-fixup (template (in std vector) Token))
+  (get-or-create-comptime-var environment num-runtime-fixups-installed int)
+  (when (= (deref num-runtime-fixups-installed) (call-on-ptr size runtime-fixup))
+    (return true))
+  (set (deref num-runtime-fixups-installed) (call-on-ptr size runtime-fixup))
+
+  (var runtime-fixup-function (addr (template (in std vector) Token))
+    (new (template (in std vector) Token)))
+  ;; Environment will handle freeing tokens for us
+  (call-on push_back (field environment comptimeTokens) runtime-fixup-function)
+  (tokenize-push (deref runtime-fixup-function)
+    (defun introspect-fixup-runtime-pointers ()
+      (token-splice-array (deref runtime-fixup))))
+  (unless (ReplaceAndEvaluateDefinition
+           environment
+           "introspect-fixup-runtime-pointers"
+           (deref runtime-fixup-function))
+    (return false))
+  (return true))
+
+(add-compile-time-hook post-references-resolved introspect-runtime-fixup-install)
+
+(defun-comptime introspect-check-initialize-called (manager (ref ModuleManager)
+                                                    module (addr Module)
+                                                    &return bool)
+  (get-or-create-comptime-var
+   (field manager environment)
+   num-runtime-fixups-installed int)
+  (unless (deref num-runtime-fixups-installed)
+    ;; No reason to call introspect-initialize because no fixups are necessary
+    (return true))
+  (get-or-create-comptime-var
+   (field manager environment)
+   introspect-initialize-called bool false)
+  (unless (deref introspect-initialize-called)
+    (Log "error: call (introspect-initialize) somewhere in your program initialization in " \
+         "order to properly set introspection metadata.\n")
+    (return false))
+  (return true))
+(add-compile-time-hook-module pre-build introspect-check-initialize-called)
+
 ;;
 ;; Types
 ;;