[wasm] Differentiate unnamed and empty names

test/mjsunit/wasm/function-names.js

Index: test/mjsunit/wasm/function-names.js
diff --git a/test/mjsunit/wasm/function-names.js b/test/mjsunit/wasm/function-names.js
new file mode 100644
index 0000000000000000000000000000000000000000..15771d847073604ce457eef33d8ccd601e084561
--- /dev/null
+++ b/test/mjsunit/wasm/function-names.js
@@ -0,0 +1,69 @@
+// 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.
+
+// Flags: --expose-wasm
+
+load("test/mjsunit/wasm/wasm-constants.js");
+load("test/mjsunit/wasm/wasm-module-builder.js");
+
+var builder = new WasmModuleBuilder();
+
+var last_func_index = builder.addFunction("exec_unreachable", kSig_v_v)
+  .addBody([kExprUnreachable])
+
+var illegal_func_name = [0xff];
+var func_names = [ "☠", illegal_func_name, "some math: (½)² = ¼", "" ];
+var expected_names = ["exec_unreachable", "☠", null,
+                      "some math: (½)² = ¼", "", "main"];
+
+for (var func_name of func_names) {
+  last_func_index = builder.addFunction(func_name, kSig_v_v)
+    .addBody([kExprCallFunction, kArity0, last_func_index]).index;
+}
+
+builder.addFunction("main", kSig_v_v)
+  .addBody([kExprCallFunction, kArity0, last_func_index])
+  .exportFunc();
+
+var module = builder.instantiate();
+
+(function testFunctionNamesAsString() {
+  var names = expected_names.concat(["testFunctionNamesAsString", null]);
+  try {
+    module.exports.main();
+    assertFalse("should throw");
+  } catch (e) {
+    var lines = e.stack.split(/\r?\n/);
+    lines.shift();
+    assertEquals(names.length, lines.length);
+    for (var i = 0; i < names.length; ++i) {
+      var line = lines[i].trim();
+      if (names[i] === null) continue;
+      var printed_name = names[i] === undefined ? "<WASM UNNAMED>" : names[i]
+      var expected_start = "at " + printed_name + " (";
+      assertTrue(line.startsWith(expected_start),
+          "should start with '" + expected_start + "': '" + line + "'");
+    }
+  }
+})();
+
+// For the remaining tests, collect the Callsite objects instead of just a
+// string:
+Error.prepareStackTrace = function(error, frames) {
+  return frames;
+};
+
+
+(function testFunctionNamesAsCallSites() {
+  var names = expected_names.concat(["testFunctionNamesAsCallSites", null]);
+  try {
+    module.exports.main();
+    assertFalse("should throw");
+  } catch (e) {
+    assertEquals(names.length, e.stack.length);
+    for (var i = 0; i < names.length; ++i) {
+      assertEquals(names[i], e.stack[i].getFunctionName());
+    }
+  }
+})();