[wasm] mjsunit support for I32 globals and test

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.
 
 class Binary extends Array {
   emit_u8(val) {
     this.push(val);
   }
 
   emit_u16(val) {
@@ skipping 86 matching lines @@
   addLocals(locals) {
     this.locals = locals;
     return this;
   }
 }
 
 class WasmModuleBuilder {
   constructor() {
     this.types = [];
     this.imports = [];
+    this.globals = [];
     this.functions = [];
     this.exports = [];
     this.table = [];
     this.segments = [];
     this.explicit = [];
     this.pad = null;
     return this;
   }
 
   addStart(start_index) {
@@ skipping 14 matching lines @@
     this.explicit.push(bytes);
     return this;
   }
 
   addType(type) {
     // TODO: canonicalize types?
     this.types.push(type);
     return this.types.length - 1;
   }
 
+  addGlobal(local_type) {
+    this.globals.push(local_type);
+    return this.globals.length - 1;
+  }
+
   addFunction(name, type) {
     let type_index = (typeof type) == "number" ? type : this.addType(type);
     let func = new WasmFunctionBuilder(name, type_index);
     func.index = this.functions.length;
     this.functions.push(func);
     return func;
   }
 
   addImportWithModule(module, name, type) {
     let type_index = (typeof type) == "number" ? type : this.addType(type);
@@ skipping 34 matching lines @@
             section.emit_u8(param);
           }
           section.emit_varint(type.results.length);
           for (let result of type.results) {
             section.emit_u8(result);
           }
         }
       });
     }
 
+    if (wasm.globals.length > 0) {
+      if (debug) print ("emitting globals @ " + binary.length);
+      binary.emit_section(kDeclGlobals, section => {
+        section.emit_varint(wasm.globals.length);
+        for (let global_type of wasm.globals) {
+          section.emit_varint(0); //length of global name

[bradnelson, 2016/08/30 23:36:20]

Formatting on this comment is odd.

[Mircea Trofin, 2016/08/31 00:08:15]

Done.

+          section.emit_u8(global_type);
+          section.emit_u8(false); // we do not support exported globals

[bradnelson, 2016/08/30 23:36:21]

These should be 2 spaces.

[Mircea Trofin, 2016/08/31 00:08:15]

Done.

+        }
+      });
+    }
+
     // Add imports section
     if (wasm.imports.length > 0) {
       if (debug) print("emitting imports @ " + binary.length);
       binary.emit_section(kDeclImports, section => {
         section.emit_varint(wasm.imports.length);
         for (let imp of wasm.imports) {
           section.emit_varint(imp.type);
           section.emit_string(imp.module);
           section.emit_string(imp.name || '');
         }
@@ skipping 151 matching lines @@
     }
     return buffer;
   }
 
   instantiate(...args) {
     let module = new WebAssembly.Module(this.toBuffer());
     let instance = new WebAssembly.Instance(module, ...args);
     return instance;
   }
 }