From 39d334d51bbfbb543c406adffe79db7e671f549a Mon Sep 17 00:00:00 2001
From: Jan Nieuwenhuizen <janneke@gnu.org>
Date: Mon, 10 Apr 2017 06:59:50 +0200
Subject: [PATCH] mescc: Support break in while.

* module/language/c99/compiler.mes (make): Add break field.
  (.break): New function.
  (clone): Support break field.
  (ast->info): Support break.
* scaffold/t.c (test): Test it.
* scaffold/mini-mes.c (lookup_symbol_): Use it; remove goto workaround.
---
 module/language/c99/compiler.mes | 49 ++++++++++++++++++++------------
 scaffold/mini-mes.c              |  4 +--
 scaffold/t.c                     |  9 ++++++
 3 files changed, 41 insertions(+), 21 deletions(-)

diff --git a/module/language/c99/compiler.mes b/module/language/c99/compiler.mes
index 47d10276..6b6cb5e7 100644
--- a/module/language/c99/compiler.mes
+++ b/module/language/c99/compiler.mes
@@ -114,8 +114,9 @@
 (define <locals> '<locals>)
 (define <function> '<function>)
 (define <text> '<text>)
+(define <break> '<break>)
 
-(define* (make o #:key (types '()) (constants '()) (functions '()) (globals '()) (init '()) (locals '()) (function #f) (text '()))
+(define* (make o #:key (types '()) (constants '()) (functions '()) (globals '()) (init '()) (locals '()) (function #f) (text '()) (break '()))
   (pmatch o
     (<info> (list <info>
                   (cons <types> types)
@@ -125,7 +126,8 @@
                   (cons <init> init)
                   (cons <locals> locals)
                   (cons <function> function)
-                  (cons <text> text)))))
+                  (cons <text> text)
+                  (cons <break> break)))))
 
 (define (.types o)
   (pmatch o
@@ -159,6 +161,10 @@
   (pmatch o
     ((<info> . ,alist) (assq-ref alist <text>))))
 
+(define (.break o)
+  (pmatch o
+    ((<info> . ,alist) (assq-ref alist <break>))))
+
 (define (info? o)
   (and (pair? o) (eq? (car o) <info>)))
 
@@ -171,7 +177,8 @@
                (init (.init o))
                (locals (.locals o))
                (function (.function o))
-               (text (.text o)))
+               (text (.text o))
+               (break (.break o)))
            (let-keywords rest
                          #f
                          ((types types)
@@ -181,8 +188,9 @@
                           (init init)
                           (locals locals)
                           (function function)
-                          (text text))
-                         (make <info> #:types types #:constants constants #:functions functions #:globals globals #:init init #:locals locals #:function function #:text text))))))
+                          (text text)
+                          (break break))
+                         (make <info> #:types types #:constants constants #:functions functions #:globals globals #:init init #:locals locals #:function function #:text text #:break break))))))
 
 (define (push-global globals)
   (lambda (o)
@@ -744,8 +752,7 @@
     (lambda (o)
       (pmatch o
         ((break) (append-text info (jump body-length)))
-        (_
-         ((ast->info info) o)))))
+        (_ ((ast->info info) o)))))
   (define (test->text test)
     (let ((value (pmatch test
                    (0 0)
@@ -985,6 +992,9 @@
         ((cast (type-name (decl-spec-list (type-spec (void)))) _)
          info)
 
+        ((break)
+         (append-text info (wrap-as (i386:Xjump (- (car (.break info)) (length (text->list text)))))))
+
         ;; FIXME: expr-stmt wrapper?
         (trans-unit info)
         ((expr-stmt) info)
@@ -1132,21 +1142,21 @@
                   #:globals (append globals (list-tail (.globals body-info) (length globals)))
                   #:locals locals)))
 
-        ;; FIXME: support break statement (see switch/case)
         ((while ,test ,body)
-         (let* ((skip-info (lambda (body-length)
-                             (clone info #:text (append text
-                                                        (wrap-as (i386:Xjump body-length))))))
-                (text (.text (skip-info 0)))
+         (let* ((skip-info (lambda (body-length test-length)
+                             (clone info
+                                    #:text (append text (wrap-as (i386:Xjump body-length)))
+                                    #:break (cons (+ (length (text->list text)) body-length test-length
+                                                     (length (i386:Xjump 0)))
+                                                  (.break info)))))
+                (text (.text (skip-info 0 0)))
                 (text-length (length text))
+                (body-info (lambda (body-length test-length)
+                             ((ast->info (skip-info body-length test-length)) body)))
 
-                (body-info (lambda (body-length)
-                             ((ast->info (skip-info body-length)) body)))
-                (body-text (list-tail (.text (body-info 0)) text-length))
+                (body-text (list-tail (.text (body-info 0 0)) text-length))
                 (body-length (length (text->list body-text)))
 
-                (body-info (body-info body-length))
-
                 (empty (clone info #:text '()))
                 (test-jump->info ((test->jump->info empty) test))
                 (test+jump-info (test-jump->info 0))
@@ -1155,7 +1165,10 @@
                 (jump-text (wrap-as (i386:Xjump (- (+ body-length test-length)))))
                 (jump-length (length (text->list jump-text)))
 
-                (test-text (.text (test-jump->info jump-length))))
+                (test-text (.text (test-jump->info jump-length)))
+
+                (body-info (body-info body-length (length (text->list test-text)))))
+
            (clone info #:text
                   (append
                    (.text body-info)
diff --git a/scaffold/mini-mes.c b/scaffold/mini-mes.c
index a6b6a3ac..4ddbc1af 100644
--- a/scaffold/mini-mes.c
+++ b/scaffold/mini-mes.c
@@ -278,11 +278,9 @@ lookup_symbol_ (SCM s)
 {
   SCM x = g_symbols;
   while (x) {
-    //if (list_of_char_equal_p (STRING (car (x)), s) == cell_t) break;
-    if (list_of_char_equal_p (STRING (car (x)), s) == cell_t) goto dun;
+    if (list_of_char_equal_p (STRING (car (x)), s) == cell_t) break;
     x = cdr (x);
   }
- dun:
   if (x) x = car (x);
   if (!x) x = make_symbol_ (s);
   return x;
diff --git a/scaffold/t.c b/scaffold/t.c
index ced944be..b7ee0013 100644
--- a/scaffold/t.c
+++ b/scaffold/t.c
@@ -683,6 +683,15 @@ test (char *p)
   return 1;
  ok0:
   
+  puts ("t: while (1) break;\n");
+  while (1) break;
+
+  puts ("t: while (1) ... break;\n");
+  while (1) {f=0;break;}
+
+  puts ("t: while (1) ... break;\n");
+  while (1) {while (1) break;break;}
+
   puts ("t: while (1) { goto label; };\n");
   while (1) {
     goto ok00;