[wasm] All strings are length-prefixed and inline

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 StringRef(string) {
-    this.pos = -1;
-    this.string = string;
-}
-
 function DataRef(data) {
     this.pos = -1;
     this.data = data;
 }
 
 function WasmFunctionBuilder(name, sig_index) {
     this.name = name;
     this.sig_index = sig_index;
     this.exports = [];
 }
@@ skipping 90 matching lines @@
 }
 
 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) {
-    bytes.push(new StringRef(string));
-    bytes.push(0);
-    bytes.push(0);
-    bytes.push(0);
+    emit_varint(bytes, string.length);
+    for (var i = 0; i < string.length; i++) {
+      emit_u8(bytes, string.charCodeAt(i));
+    }
 }
 
 function emit_data_ref(bytes, string) {
     bytes.push(new DataRef(string));
     bytes.push(0);
     bytes.push(0);
     bytes.push(0);
 }
 
 function emit_varint(bytes, val) {
@@ skipping 38 matching lines @@
     }
 
     // Add imports section
     if (this.imports.length > 0) {
         if (debug) print("emitting imports @ " + bytes.length);
         emit_u8(bytes, kDeclImportTable);
         emit_varint(bytes, this.imports.length);
         for (imp of this.imports) {
             emit_varint(bytes, imp.sig_index);
             emit_string(bytes, imp.module);
-            if (imp.name == undefined) {
-              emit_u32(bytes, 0);
-            } else {
-              emit_string(bytes, imp.name);
-            }
+            emit_string(bytes, imp.name || '');
         }
     }
 
     // Add functions section
     var names = false;
     var exports = 0;
     if (this.functions.length > 0) {
         if (debug) print("emitting functions @ " + bytes.length);
         emit_u8(bytes, kDeclFunctions);
         emit_varint(bytes, this.functions.length);
@@ skipping 93 matching lines @@
         if (debug) print("emitting explicit @ " + bytes.length);
         for (var i = 0; i < exp.length; i++) {
             emit_u8(bytes, exp[i]);
         }
     }
 
     // End the module.
     if (debug) print("emitting end @ " + bytes.length);
     emit_u8(bytes, kDeclEnd);
 
-    // Collect references and canonicalize strings.
+    // Collect references.
     var strings = new Object();
     var data_segments = [];
     var count = 0;
     for (var i = 0; i < bytes.length; i++) {
         var b = bytes[i];
-        if (b instanceof StringRef) {
-            count++;
-            var prev = strings[b.string];
-            if (prev) {
-                bytes[i] = prev;
-            } else {
-                strings[b.string] = b;
-            }
-        }
         if (b instanceof DataRef) {
             data_segments.push(b);
             count++;
         }
     }
 
     if (count > 0) {
-        // Emit strings.
-        if (debug) print("emitting strings @ " + bytes.length);
-        for (str in strings) {
-            var ref = strings[str];
-            if (!(ref instanceof StringRef)) continue;
-            if (debug) print("  \"" + str + "\" @ " + bytes.length);
-            ref.pos = bytes.length;
-            for (var i = 0; i < str.length; i++) {
-                emit_u8(bytes, str.charCodeAt(i));
-            }
-            emit_u8(bytes, 0);  // null terminator.
-        }
         // Emit data.
         if (debug) print("emitting data @ " + bytes.length);
         for (ref of data_segments) {
             ref.pos = bytes.length;
             for (var i = 0; i < ref.data.length; i++) {
                 emit_u8(bytes, ref.data[i]);
             }
         }
         // Update references to strings and data.
         for (var i = 0; i < bytes.length; i++) {
             var b = bytes[i];
-            if (b instanceof StringRef || b instanceof DataRef) {
+            if (b instanceof DataRef) {
                 bytes[i] = b.pos & 0xFF;
                 bytes[i + 1] = (b.pos >> 8) & 0xFF;
                 bytes[i + 2] = (b.pos >> 16) & 0xFF;
                 bytes[i + 3] = (b.pos >> 24) & 0xFF;
             }
         }
     }
 
     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);
     }
 }