[wasm] Add inspector test for stepping

test/inspector/debugger/wasm-stepping.js

Index: test/inspector/debugger/wasm-stepping.js
diff --git a/test/inspector/debugger/wasm-stepping.js b/test/inspector/debugger/wasm-stepping.js
new file mode 100644
index 0000000000000000000000000000000000000000..8cf14d361c048b43180efe597934fe6fcd6a8f1c
--- /dev/null
+++ b/test/inspector/debugger/wasm-stepping.js
@@ -0,0 +1,160 @@
+// Copyright 2017 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.
+
+load('test/mjsunit/wasm/wasm-constants.js');
+load('test/mjsunit/wasm/wasm-module-builder.js');
+
+var builder = new WasmModuleBuilder();
+
+var func_a_idx =
+    builder.addFunction('wasm_A', kSig_v_v).addBody([kExprNop, kExprNop]).index;
+
+// wasm_B calls wasm_A <param0> times.
+builder.addFunction('wasm_B', kSig_v_i)
+    .addBody([
+      // clang-format off
+      kExprLoop, kWasmStmt,               // while
+        kExprGetLocal, 0,                 // -
+        kExprIf, kWasmStmt,               // if <param0> != 0
+          kExprGetLocal, 0,               // -
+          kExprI32Const, 1,               // -
+          kExprI32Sub,                    // -
+          kExprSetLocal, 0,               // decrease <param0>
+          kExprCallFunction, func_a_idx,  // -
+          kExprBr, 1,                     // continue
+          kExprEnd,                       // -
+        kExprEnd,                         // break
+      // clang-format on
+    ])
+    .exportAs('main');
+
+var module_bytes = builder.toArray();
+
+function instantiate(bytes) {
+  var buffer = new ArrayBuffer(bytes.length);
+  var view = new Uint8Array(buffer);
+  for (var i = 0; i < bytes.length; ++i) {
+    view[i] = bytes[i] | 0;
+  }
+
+  var module = new WebAssembly.Module(buffer);
+  // Set global variable.
+  instance = new WebAssembly.Instance(module);
+}
+
+var evalWithUrl = (code, url) => Protocol.Runtime.evaluate(
+    {'expression': code + '\n//# sourceURL=v8://test/' + url});
+
+Protocol.Debugger.onPaused(handlePaused);
+var wasm_B_scriptId;
+var step_actions = [
+  'stepInto',  // == stepOver, to call instruction
+  'stepInto',  // into call to wasm_A
+  'stepOver',  // over first nop
+  'stepOut',   // out of wasm_A
+  'stepOut',   // out of wasm_B, stop on breakpoint again
+  'stepOver',  // to call
+  'stepOver',  // over call
+  'resume',    // to next breakpoint (third iteration)
+  'stepInto',  // to call
+  'stepInto',  // into wasm_A
+  'stepOut',   // out to wasm_B
+  // now step 9 times, until we are in wasm_A again.
+  'stepInto', 'stepInto', 'stepInto', 'stepInto', 'stepInto', 'stepInto',
+  'stepInto', 'stepInto', 'stepInto',
+  // 3 more times, back to wasm_B.
+  'stepInto', 'stepInto', 'stepInto',
+  // then just resume.
+  'resume'
+];
+var sources = {};
+var urls = {};
+var afterTwoSourcesCallback;
+
+Protocol.Debugger.enable()
+    .then(() => InspectorTest.log('Installing code an global variable.'))
+    .then(
+        () => evalWithUrl('var instance;\n' + instantiate.toString(), 'setup'))
+    .then(() => InspectorTest.log('Calling instantiate function.'))
+    .then(
+        () =>
+            (evalWithUrl(
+                 'instantiate(' + JSON.stringify(module_bytes) + ')',
+                 'callInstantiate'),
+             0))
+    .then(waitForTwoWasmScripts)
+    .then(
+        () => InspectorTest.log(
+            'Setting breakpoint on line 7 (on the setlocal before the call), url ' +
+            urls[wasm_B_scriptId]))
+    .then(
+        () => Protocol.Debugger.setBreakpoint(
+            {'location': {'scriptId': wasm_B_scriptId, 'lineNumber': 7}}))
+    .then(printFailure)
+    .then(msg => InspectorTest.logMessage(msg.result.actualLocation))
+    .then(() => evalWithUrl('instance.exports.main(4)', 'runWasm'))
+    .then(() => InspectorTest.log('exports.main returned!'))
+    .then(() => InspectorTest.log('Finished!'))
+    .then(InspectorTest.completeTest);
+
+function printFailure(message) {
+  if (!message.result) {
+    InspectorTest.logMessage(message);
+  }
+  return message;
+}
+
+function waitForTwoWasmScripts() {
+  var num = 0;
+  InspectorTest.log('Waiting for two wasm scripts to be parsed.');
+  var promise = new Promise(fulfill => gotBothSources = fulfill);
+  function waitForMore() {
+    if (num == 2) return promise;
+    Protocol.Debugger.onceScriptParsed()
+        .then(handleNewScript)
+        .then(waitForMore);
+  }
+  function handleNewScript(msg) {
+    var url = msg.params.url;
+    if (!url.startsWith('wasm://')) {
+      InspectorTest.log('Ignoring script with url ' + url);
+      return;
+    }
+    num += 1;
+    var scriptId = msg.params.scriptId;
+    urls[scriptId] = url;
+    InspectorTest.log('Got wasm script: ' + url);
+    if (url.substr(-2) == '-1') wasm_B_scriptId = scriptId;
+    InspectorTest.log('Requesting source for ' + url + '...');
+    Protocol.Debugger.getScriptSource({scriptId: scriptId})
+        .then(printFailure)
+        .then(msg => sources[scriptId] = msg.result.scriptSource)
+        .then(InspectorTest.log)
+        .then(() => Object.keys(sources).length == 2 ? gotBothSources() : 0);
+  }
+  waitForMore();
+  return promise;
+}
+
+function printPauseLocation(scriptId, lineNr, columnNr) {
+  var lines = sources[scriptId].split('\n');
+  var line = '<illegal line number>';
+  if (lineNr < lines.length) {
+    line = lines[lineNr];
+    if (columnNr < line.length) {
+      line = line.substr(0, columnNr) + '>' + line.substr(columnNr);
+    }
+  }
+  InspectorTest.log(
+      'Paused at ' + urls[scriptId] + ':' + lineNr + ':' + columnNr + ': ' +
+      line);
+}
+
+function handlePaused(msg) {
+  var loc = msg.params.callFrames[0].location;
+  printPauseLocation(loc.scriptId, loc.lineNumber, loc.columnNumber);
+  var action = step_actions.shift();
+  InspectorTest.log('Step action: ' + action);
+  Protocol.Debugger[action]();
+}