Fix CREATE

Update input and output.
This opcode requires special treatment hence an additional case in the
conditional. We only overwrite the value stored in the opointer (with
zero) if the call does not succeed.

Author: lrettig

wasm/generateInterface.js

@@ -116,8 +116,8 @@ const interfaceManifest = {
   CREATE: {
     name: 'create',
     async: true,
-    input: ['i128', 'readOffset', 'length'],
-    output: ['address']
+    input: ['i128', 'readOffset', 'length', 'opointer'],
+    output: ['i32']
   },
   CALL: {
     name: 'call',
@@ -329,6 +329,15 @@ function generateManifest (interfaceManifest, opts) {
       call += `)
       (drop (call $bswap_m256 (i32.add (i32.const 32) (get_global $sp))))
       `
+    } else if (opcode === 'CREATE') {
+      // Check the return value from the EEI method.
+      // 0 = success, 1 = failure, 2 = revert
+      // iff return === 0, there is nothing to do as the address has already been loaded.
+      // otherwise, we must return 0 instead, overwriting whatever was read from memory.
+      call = `(if (i32.ne ${call}) (i32.const 0))
+        (then (i64.store
+          (i32.add (get_global $sp) (i32.const ${spOffset * 32}))
+          (i64.const 0))))`
     } else if (output === 'i32') {
       if (useAsyncAPI && op.async) {
         call += '(get_local $callback)'