Flow improvements

Makes the internal API for working with flows more explicit in an attempt to avoid further issues. Also tackles remaining issues with 'continue' statements in 'for' loops.

tests/compiler/for.optimized.wat

@@ -9,6 +9,7 @@
  (start $start)
  (func $start (; 1 ;) (type $v)
   (local $0 i32)
+  (local $1 i32)
   (block $break|0
    (set_global $for/i
     (i32.const 0)
@@ -153,5 +154,53 @@
     (unreachable)
    )
   )
+  (block $break|6
+   (set_local $0
+    (i32.const 0)
+   )
+   (loop $repeat|6
+    (br_if $break|6
+     (i32.ge_s
+      (get_local $0)
+      (i32.const 10)
+     )
+    )
+    (block $break|7
+     (set_local $1
+      (i32.const 0)
+     )
+     (loop $repeat|7
+      (block $continue|7
+       (br_if $break|7
+        (i32.ge_s
+         (get_local $1)
+         (i32.const 10)
+        )
+       )
+       (br_if $continue|7
+        (i32.eq
+         (get_local $0)
+         (get_local $1)
+        )
+       )
+      )
+      (set_local $1
+       (i32.add
+        (get_local $1)
+        (i32.const 1)
+       )
+      )
+      (br $repeat|7)
+     )
+    )
+    (set_local $0
+     (i32.add
+      (get_local $0)
+      (i32.const 1)
+     )
+    )
+    (br $repeat|6)
+   )
+  )
  )
 )

tests/compiler/for.ts

@@ -17,3 +17,9 @@ for (;;) if (--i == 0) break;
 
 for (var k: i32 = 0; k < 10; ++k) continue;
 assert(k == 10);
+
+for (let i = 0; i < 10; i++) { // without continue block
+  for (let j = 0; j < 10; j++) { // with continue block
+    if (i === j) continue;
+  }
+}

tests/compiler/for.untouched.wat

@@ -11,6 +11,8 @@
  (func $start (; 1 ;) (type $v)
   (local $0 i32)
   (local $1 i32)
+  (local $2 i32)
+  (local $3 i32)
   (block $break|0
    (set_global $for/i
     (i32.const 0)
@@ -201,5 +203,58 @@
     (unreachable)
    )
   )
+  (block $break|6
+   (set_local $2
+    (i32.const 0)
+   )
+   (loop $repeat|6
+    (br_if $break|6
+     (i32.eqz
+      (i32.lt_s
+       (get_local $2)
+       (i32.const 10)
+      )
+     )
+    )
+    (block $break|7
+     (set_local $3
+      (i32.const 0)
+     )
+     (loop $repeat|7
+      (block $continue|7
+       (br_if $break|7
+        (i32.eqz
+         (i32.lt_s
+          (get_local $3)
+          (i32.const 10)
+         )
+        )
+       )
+       (if
+        (i32.eq
+         (get_local $2)
+         (get_local $3)
+        )
+        (br $continue|7)
+       )
+      )
+      (set_local $3
+       (i32.add
+        (get_local $3)
+        (i32.const 1)
+       )
+      )
+      (br $repeat|7)
+     )
+    )
+    (set_local $2
+     (i32.add
+      (get_local $2)
+      (i32.const 1)
+     )
+    )
+    (br $repeat|6)
+   )
+  )
  )
 )