[wasm] Provide better stack traces for asm.js code

test/mjsunit/wasm/asm-wasm-stack.js

Index: test/mjsunit/wasm/asm-wasm-stack.js
diff --git a/test/mjsunit/wasm/asm-wasm-stack.js b/test/mjsunit/wasm/asm-wasm-stack.js
new file mode 100644
index 0000000000000000000000000000000000000000..b7dac31e16c9b38d6a9730bcd25f9c7b542b63df
--- /dev/null
+++ b/test/mjsunit/wasm/asm-wasm-stack.js
@@ -0,0 +1,98 @@
+// 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: --validate-asm --allow-natives-syntax
+
+var filename = '(?:[^ ]+/)?test/mjsunit/wasm/asm-wasm-stack.js';
+filename = filename.replace(/\//g, '[/\\\\]');
+
+function checkPreformattedStack(e, expected_lines) {
+  print('preformatted stack: ' + e.stack);
+  var lines = e.stack.split('\n');
+  assertEquals(expected_lines.length, lines.length);
+  for (var i = 0; i < lines.length; ++i) {
+    assertMatches(expected_lines[i], lines[i], 'line ' + i);
+  }
+}
+
+function checkFunctionsOnCallsites(e, locations) {
+  var stack = e.stack;
+  print('callsite objects (size ' + stack.length + '):');
+  for (var i = 0; i < stack.length; ++i) {
+    var s = stack[i];
+    print(
+        ' [' + i + '] ' + s.getFunctionName() + ' (' + s.getFileName() + ':' +
+        s.getLineNumber() + ':' + s.getColumnNumber() + ')');
+  }
+  assertEquals(locations.length, stack.length, 'stack size');
+  for (var i = 0; i < locations.length; ++i) {
+    var cs = stack[i];
+    assertMatches('^' + filename + '$', cs.getFileName(), 'file name at ' + i);
+    assertEquals(
+        locations[i][0], cs.getFunctionName(), 'function name at ' + i);
+    assertEquals(locations[i][1], cs.getLineNumber(), 'line number at ' + i);
+    assertEquals(
+        locations[i][2], cs.getColumnNumber(), 'column number at ' + i);
+    assertNotNull(cs.getThis(), 'receiver should be global');
+    assertEquals(stack[0].getThis(), cs.getThis(), 'receiver should be global');
+  }
+}
+
+function throwException() {
+  throw new Error('exception from JS');
+}
+
+function generateWasmFromAsmJs(stdlib, foreign, heap) {
+  'use asm';
+  var throwFunc = foreign.throwFunc;
+  function callThrow() {
+    throwFunc();
+  }
+  function redirectFun() {
+    callThrow();
+  }
+  return redirectFun;
+}
+
+(function PreformattedStackTraceFromJS() {
+  var fun = generateWasmFromAsmJs(this, {throwFunc: throwException}, undefined);
+  var e = null;
+  try {
+    fun();
+  } catch (ex) {
+    e = ex;
+  }
+  assertInstanceof(e, Error, 'exception should have been thrown');
+  checkPreformattedStack(e, [
+    '^Error: exception from JS$',
+    '^ *at throwException \\(' + filename + ':43:9\\)$',
+    '^ *at callThrow \\(' + filename + ':50:5\\)$',
+    '^ *at redirectFun \\(' + filename + ':53:5\\)$',
+    '^ *at PreformattedStackTraceFromJS \\(' + filename + ':62:5\\)$',
+    '^ *at ' + filename + ':75:3$'
+  ]);
+})();
+
+// Now collect the Callsite objects instead of just a string.
+Error.prepareStackTrace = function(error, frames) {
+  return frames;
+};
+
+(function CallsiteObjectsFromJS() {
+  var fun = generateWasmFromAsmJs(this, {throwFunc: throwException}, undefined);
+  var e = null;
+  try {
+    fun();
+  } catch (ex) {
+    e = ex;
+  }
+  assertInstanceof(e, Error, 'exception should have been thrown');
+  checkFunctionsOnCallsites(e, [
+    ['throwException', 43, 9],         // --
+    ['callThrow', 50, 5],              // --
+    ['redirectFun', 53, 5],            // --
+    ['CallsiteObjectsFromJS', 86, 5],  // --
+    [null, 98, 3]
+  ]);
+})();