Avoid new blocks in binary reading/writing (#1165)

* don't emit a toplevel block if we don't need to, as in wasm it is a list context

* don't create unnecessary blocks in wasm reading

1 files changed, 27 insertions, 31 deletions

diff --git a/test/example/c-api-unused-mem.txt b/test/example/c-api-unused-mem.txt
index 60bdbe51d..6bb3c8a7c 100644
--- a/test/example/c-api-unused-mem.txt
+++ b/test/example/c-api-unused-mem.txt
@@ -46,7 +46,7 @@
   (call $main)
  )
 )
-177
+169
 (module
  (type $0 (func))
  (type $1 (func))
@@ -58,45 +58,41 @@
   (local $var$0 i32)
   (local $var$1 i32)
   (local $var$2 i64)
-  (block $label$0
-   (block $label$1
-    (set_local $var$0
-     (i32.load
-      (i32.const 0)
-     )
-    )
-    (block $label$2
-     (br $label$1)
+  (block $label$1
+   (set_local $var$0
+    (i32.load
+     (i32.const 0)
     )
    )
-   (block $label$3
-    (block $label$4
-     (block $label$5
-     )
-     (block $label$6
-      (br $label$4)
-     )
+   (block $label$2
+    (br $label$1)
+   )
+  )
+  (block $label$3
+   (block $label$4
+    (block $label$5
+    )
+    (block $label$6
+     (br $label$4)
     )
-    (block $label$7
-     (block $label$8
-      (i32.store
-       (i32.const 0)
-       (get_local $var$0)
-      )
-      (return)
+   )
+   (block $label$7
+    (block $label$8
+     (i32.store
+      (i32.const 0)
+      (get_local $var$0)
      )
-     (unreachable)
+     (return)
     )
+    (unreachable)
    )
   )
  )
  (func $__wasm_start (type $1)
-  (block $label$0
-   (i32.store
-    (i32.const 0)
-    (i32.const 65535)
-   )
-   (call $main)
+  (i32.store
+   (i32.const 0)
+   (i32.const 65535)
   )
+  (call $main)
  )
 )