mescc: Tinycc support: union.struct.

* module/language/c99/compiler.mes (decl->info): Support struct inside union.
* scaffold/tests/78-union-struct.c: Test it.
* make.scm (add-scaffold-test): Build it.

make.scm

@@ -157,7 +157,8 @@ exec ${GUILE-guile} --no-auto-compile -L . -L guile -C . -C guile -s "$0" ${1+"$
    "74-multi-line-string"
    "75-struct-union"
    "76-pointer-arithmetic"
-   "77-pointer-assign"))
+   "77-pointer-assign"
+   "78-union-struct"))
 
 (add-target (group "check-scaffold-tests/7" #:dependencies (filter (target-prefix? "check-scaffold/tests/7") %targets)))
 

module/language/c99/compiler.mes

@@ -1055,8 +1055,9 @@
        (let* ((type0 (ident->type info struct0))
               (type1 (field-type info type0 field0))
               (offset (+ (field-offset info type0 field0)
-                         (field-offset info type1 field1))))
+                         (field-offset info type1 field1)))
-         (append-text info (append ((ident-address->accu info) struct0)
+              (ptr0 (ident->pointer info struct0)))
+         (append-text info (append ((ident->accu info) struct0)
                                    (wrap-as (i386:accu+value offset))))))
 
       ;; bar->foo.i
@@ -1628,14 +1629,17 @@
     ((p-expr (ident ,name)) (ident->type info name))
     ((array-ref ,index (p-expr (ident ,array))) (ident->type info array))
     ((i-sel (ident ,field) (p-expr (ident ,struct)))
-     (let ((type0 (ident->type info struct)))
+     (let* ((type0 (ident->type info struct))
-       (field-type info `("tag" ,type0) field)))
+            (type0 (if (pair? type0) type0 `("tag" ,type0))))
+       (field-type info type0 field)))
     ((d-sel (ident ,field) (p-expr (ident ,struct)))
-     (let ((type0 (ident->type info struct)))
+     (let* ((type0 (ident->type info struct))
-       (field-type info `("tag" ,type0) field)))
+            (type0 (if (pair? type0) type0 `("tag" ,type0))))
+       (field-type info type0 field)))
     ((d-sel (ident ,field) (array-ref ,index (p-expr (ident ,array))))
-     (let ((type0 (ident->type info array)))
+     (let* ((type0 (ident->type info array))
-       (field-type info `("tag" ,type0) field)))
+            (type0 (if (pair? type0) type0 `("tag" ,type0))))
+       (field-type info type0 field)))
     (_ (error "p-expr->type: unsupported: " o))))
 
 (define (local-var? o) ;; formals < 0, locals > 0
@@ -1858,6 +1862,11 @@
          (let ((type-entry (struct->type-entry name (map (struct-field info) fields))))
            (clone info #:types (cons type-entry types))))
 
+        ;; union
+        ((decl (decl-spec-list (type-spec (union-def (ident ,name) (field-list . ,fields)))))
+         (let ((type-entry (union->type-entry name (map (struct-field info) fields))))
+           (clone info #:types (cons type-entry types))))
+
         ;; enum e i;
         ((decl (decl-spec-list (type-spec (enum-ref (ident ,type)))) (init-declr-list (init-declr (ident ,name))))
          (let ((type "int")) ;; FIXME
@@ -1953,14 +1962,6 @@
            (clone info
                   #:constants (append constants (.constants info)))))
 
-        ((decl (decl-spec-list (type-spec (struct-def (ident ,name) (field-list . ,fields)))))
-         (let ((type-entry (struct->type-entry name (map (struct-field info) fields))))
-           (clone info #:types (cons type-entry types))))
-
-        ((decl (decl-spec-list (type-spec (union-def (ident ,name) (field-list . ,fields)))))
-         (let ((type-entry (union->type-entry name (map (struct-field info) fields))))
-           (clone info #:types (cons type-entry types))))
-
         ((decl (decl-spec-list (type-spec (struct-def (ident ,type) (field-list . ,fields))))
                (init-declr-list (init-declr (ident ,name))))
          (let ((info ((decl->info info) `(decl (decl-spec-list (type-spec (struct-def (ident ,type) (field-list . ,fields))))))))
@@ -2062,7 +2063,7 @@
                 (info (clone info #:globals globals))
                 (struct? (and (zero? pointer)
                               (or (and (pair? type) (equal? (car type) "tag"))
-                                  (eq? (type:type (ast-type->type info xtype)) 'struct))))
+                                  (memq (type:type (ast-type->type info xtype)) '(struct union)))))
                 (pointer (if struct? -1 pointer))
                 (size (if (<= pointer 0) (ast-type->size info type)
                           4)))

scaffold/tests/78-union-struct.c

@@ -0,0 +1,46 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * Mes --- Maxwell Equations of Software
+ * Copyright © 2017 Jan Nieuwenhuizen <janneke@gnu.org>
+ *
+ * This file is part of Mes.
+ *
+ * Mes is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * Mes is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Mes.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "30-test.i"
+
+#include <stdint.h>
+
+struct foo {
+    int i;
+    void *p;
+};
+
+union bar {
+  struct foo foo;
+};
+
+union bar bar;
+
+int
+test ()
+{
+  bar.foo.i = 2;
+  bar.foo.p = "hallo";
+
+  union bar *pb = &bar;
+  if (pb->foo.i != 2) return 1;
+
+  return 0;
+}