[wasm] Add UTF-8 validation

test/mjsunit/wasm/wasm-module-builder.js

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 function WasmFunctionBuilder(name, sig_index) {
     this.name = name;
     this.sig_index = sig_index;
     this.exports = [];
 }
 
@@ skipping 57 matching lines @@
     return func;
 }
 
 WasmModuleBuilder.prototype.addImportWithModule = function(module, name, sig) {
   var sig_index = (typeof sig) == "number" ? sig : this.addSignature(sig);
   this.imports.push({module: module, name: name, sig_index: sig_index});
   return this.imports.length - 1;
 }
 
 WasmModuleBuilder.prototype.addImport = function(name, sig) {
-  var sig_index = (typeof sig) == "number" ? sig : this.addSignature(sig);
-  this.imports.push({module: name, name: undefined, sig_index: sig_index});
-  return this.imports.length - 1;
+  this.addImportWithModule(name, undefined, sig);
 }
 
 WasmModuleBuilder.prototype.addDataSegment = function(addr, data, init) {
     this.data_segments.push({addr: addr, data: data, init: init});
     return this.data_segments.length - 1;
 }
 
 WasmModuleBuilder.prototype.appendToFunctionTable = function(array) {
     this.function_table = this.function_table.concat(array);
     return this;
 }
 
 function emit_u8(bytes, val) {
     bytes.push(val & 0xff);
 }
 
 function emit_u16(bytes, val) {
     bytes.push(val & 0xff);
     bytes.push((val >> 8) & 0xff);
 }
 
 function emit_u32(bytes, val) {
     bytes.push(val & 0xff);
     bytes.push((val >> 8) & 0xff);
     bytes.push((val >> 16) & 0xff);
     bytes.push((val >> 24) & 0xff);
 }
 
 function emit_string(bytes, string) {
-    emit_varint(bytes, string.length);
-    for (var i = 0; i < string.length; i++) {
-      emit_u8(bytes, string.charCodeAt(i));
+    // When testing illegal names, we pass a byte array directly.
+    if (string instanceof Array) {
+      emit_varint(bytes, string.length);
+      emit_bytes(bytes, string);
+      return;
+    }
+
+    // This is the hacky way to convert a JavaScript scring to a UTF8 encoded
+    // string only containing single-byte characters.
+    var string_utf8 = unescape(encodeURIComponent(string));
+    emit_varint(bytes, string_utf8.length);
+    for (var i = 0; i < string_utf8.length; i++) {
+      emit_u8(bytes, string_utf8.charCodeAt(i));
     }
 }
 
 function emit_varint(bytes, val) {
     while (true) {
         var v = val & 0xff;
         val = val >>> 7;
         if (val == 0) {
             bytes.push(v);
             break;
@@ skipping 179 matching lines @@
         emit_bytes(bytes, exp);
     }
 
     // Add function names.
     if (has_names) {
         if (debug) print("emitting names @ " + bytes.length);
         emit_section(bytes, kDeclNames, function(bytes) {
             emit_varint(bytes, wasm.functions.length);
             for (func of wasm.functions) {
                 var name = func.name == undefined ? "" : func.name;
-               emit_string(bytes, name);
-               emit_u8(bytes, 0);  // local names count == 0
+                emit_string(bytes, name);
+                emit_u8(bytes, 0);  // local names count == 0
             }
         });
     }
 
     // End the module.
     if (debug) print("emitting end @ " + bytes.length);
     emit_section(bytes, kDeclEnd, function(bytes) {});
 
     return bytes;
 }
@@ skipping 11 matching lines @@
 }
 
 WasmModuleBuilder.prototype.instantiate = function(ffi, memory) {
     var buffer = this.toBuffer();
     if (memory != undefined) {
       return Wasm.instantiateModule(buffer, ffi, memory);
     } else {
       return Wasm.instantiateModule(buffer, ffi);
     }
 }