Reland: [modules] Add partial support for debug-scopes.

Setting variables is not yet implemented.

R=adamk@chromium.org
BUG=v8:1569

Review-Url: https://codereview.chromium.org/2445683002
Cr-Commit-Position: refs/heads/master@{#40566}

src/ast/scopeinfo.cc

@@ -647,12 +647,8 @@ int ScopeInfo::ModuleIndex(Handle<String> name, VariableMode* mode,
   int entry = ModuleVariablesIndex();
   for (int i = 0; i < module_vars_count; ++i) {
     if (*name == get(entry + kModuleVariableNameOffset)) {
-      int index = Smi::cast(get(entry + kModuleVariableIndexOffset))->value();
-      int properties =
-          Smi::cast(get(entry + kModuleVariablePropertiesOffset))->value();
-      *mode = VariableModeField::decode(properties);
-      *init_flag = InitFlagField::decode(properties);
-      *maybe_assigned_flag = MaybeAssignedFlagField::decode(properties);
+      int index;
+      ModuleVariable(i, nullptr, &index, mode, init_flag, maybe_assigned_flag);
       return index;
     }
     entry += kModuleVariableEntryLength;
@@ -794,6 +790,34 @@ int ScopeInfo::ModuleVariableCountIndex() { return ModuleInfoIndex() + 1; }
 
 int ScopeInfo::ModuleVariablesIndex() { return ModuleVariableCountIndex() + 1; }
 
+void ScopeInfo::ModuleVariable(int i, String** name, int* index,
+                               VariableMode* mode,
+                               InitializationFlag* init_flag,
+                               MaybeAssignedFlag* maybe_assigned_flag) {
+  DCHECK_LE(0, i);
+  DCHECK_LT(i, Smi::cast(get(ModuleVariableCountIndex()))->value());
+
+  int entry = ModuleVariablesIndex() + i * kModuleVariableEntryLength;
+  int properties =
+      Smi::cast(get(entry + kModuleVariablePropertiesOffset))->value();
+
+  if (name != nullptr) {
+    *name = String::cast(get(entry + kModuleVariableNameOffset));
+  }
+  if (index != nullptr) {
+    *index = Smi::cast(get(entry + kModuleVariableIndexOffset))->value();
+  }
+  if (mode != nullptr) {
+    *mode = VariableModeField::decode(properties);
+  }
+  if (init_flag != nullptr) {
+    *init_flag = InitFlagField::decode(properties);
+  }
+  if (maybe_assigned_flag != nullptr) {
+    *maybe_assigned_flag = MaybeAssignedFlagField::decode(properties);
+  }
+}
+
 #ifdef DEBUG
 
 static void PrintList(const char* list_name,
@@ -867,7 +891,8 @@ Handle<ModuleInfo> ModuleInfo::New(Isolate* isolate, Zone* zone,
   {
     int i = 0;
     for (auto entry : descr->special_exports()) {
-      special_exports->set(i++, *entry->Serialize(isolate));
+      Handle<ModuleInfoEntry> serialized_entry = entry->Serialize(isolate);
+      special_exports->set(i++, *serialized_entry);
     }
   }
 
@@ -877,7 +902,8 @@ Handle<ModuleInfo> ModuleInfo::New(Isolate* isolate, Zone* zone,
   {
     int i = 0;
     for (auto entry : descr->namespace_imports()) {
-      namespace_imports->set(i++, *entry->Serialize(isolate));
+      Handle<ModuleInfoEntry> serialized_entry = entry->Serialize(isolate);
+      namespace_imports->set(i++, *serialized_entry);
     }
   }
 
@@ -891,7 +917,9 @@ Handle<ModuleInfo> ModuleInfo::New(Isolate* isolate, Zone* zone,
   {
     int i = 0;
     for (const auto& elem : descr->regular_imports()) {
-      regular_imports->set(i++, *elem.second->Serialize(isolate));
+      Handle<ModuleInfoEntry> serialized_entry =
+          elem.second->Serialize(isolate);
+      regular_imports->set(i++, *serialized_entry);
     }
   }
 
@@ -904,5 +932,20 @@ Handle<ModuleInfo> ModuleInfo::New(Isolate* isolate, Zone* zone,
   return result;
 }
 
+Handle<ModuleInfoEntry> ModuleInfo::LookupRegularImport(
+    Handle<ModuleInfo> info, Handle<String> local_name) {
+  Isolate* isolate = info->GetIsolate();
+  Handle<FixedArray> regular_imports(info->regular_imports(), isolate);
+  for (int i = 0, n = regular_imports->length(); i < n; ++i) {
+    Handle<ModuleInfoEntry> entry(
+        ModuleInfoEntry::cast(regular_imports->get(i)), isolate);
+    if (String::cast(entry->local_name())->Equals(*local_name)) {
+      return entry;
+    }
+  }
+  UNREACHABLE();
+  return Handle<ModuleInfoEntry>();
+}
+
 }  // namespace internal
 }  // namespace v8

src/contexts.cc

@@ -82,7 +82,7 @@ Context* Context::declaration_context() {
 Context* Context::closure_context() {
   Context* current = this;
   while (!current->IsFunctionContext() && !current->IsScriptContext() &&
-         !current->IsNativeContext()) {
+         !current->IsModuleContext() && !current->IsNativeContext()) {
     current = current->previous();
     DCHECK(current->closure() == closure());
   }

src/debug/debug-scopes.cc

@@ -101,6 +101,8 @@ ScopeIterator::ScopeIterator(Isolate* isolate, FrameInspector* frame_inspector,
       // Language mode may be inherited from the eval caller.
       // Retrieve it from shared function info.
       info->set_language_mode(shared_info->language_mode());
+    } else if (scope_info->scope_type() == MODULE_SCOPE) {
+      info->set_module();
     } else {
       DCHECK(scope_info->scope_type() == SCRIPT_SCOPE);
     }
@@ -608,17 +610,10 @@ MaybeHandle<JSObject> ScopeIterator::MaterializeModuleScope() {
   Handle<Context> context = CurrentContext();
   DCHECK(context->IsModuleContext());
   Handle<ScopeInfo> scope_info(context->scope_info());
-
-  // Allocate and initialize a JSObject with all the members of the debugged
-  // module.
   Handle<JSObject> module_scope =
       isolate_->factory()->NewJSObjectWithNullProto();
-
-  // Fill all context locals.
   CopyContextLocalsToScopeObject(scope_info, context, module_scope);
-
-  // TODO(neis): Also collect stack locals as well as imports and exports.
-
+  CopyModuleVarsToScopeObject(scope_info, context, module_scope);
   return module_scope;
 }
 
@@ -789,6 +784,51 @@ void ScopeIterator::CopyContextLocalsToScopeObject(
   }
 }
 
+void ScopeIterator::CopyModuleVarsToScopeObject(Handle<ScopeInfo> scope_info,
+                                                Handle<Context> context,
+                                                Handle<JSObject> scope_object) {
+  Isolate* isolate = scope_info->GetIsolate();
+
+  int module_variable_count =
+      Smi::cast(scope_info->get(scope_info->ModuleVariableCountIndex()))
+          ->value();
+  for (int i = 0; i < module_variable_count; ++i) {
+    Handle<String> local_name;
+    bool is_export;
+    {
+      String* name;
+      int index;
+      scope_info->ModuleVariable(i, &name, &index);
+      CHECK(!ScopeInfo::VariableIsSynthetic(name));
+      local_name = handle(name, isolate);
+      is_export = index == Variable::kModuleExportIndex;
+    }
+
+    Handle<Object> value;
+    if (is_export) {
+      value =
+          Module::LoadExport(handle(context->module(), isolate), local_name);
+    } else {
+      Handle<ModuleInfo> module_info(scope_info->ModuleDescriptorInfo(),
+                                     isolate);
+      Handle<ModuleInfoEntry> entry =
+          ModuleInfo::LookupRegularImport(module_info, local_name);
+      Handle<String> import_name(String::cast(entry->import_name()), isolate);
+      int module_request = Smi::cast(entry->module_request())->value();
+      value = Module::LoadImport(handle(context->module(), isolate),
+                                 import_name, module_request);
+    }
+
+    // Reflect variables under TDZ as undefined in scope object.
+    if (value->IsTheHole(isolate)) continue;
+    // This should always succeed.
+    // TODO(verwaest): Use AddDataProperty instead.
+    JSObject::SetOwnPropertyIgnoreAttributes(scope_object, local_name, value,
+                                             NONE)
+        .Check();
+  }
+}
+
 void ScopeIterator::CopyContextExtensionToScopeObject(
     Handle<Context> context, Handle<JSObject> scope_object,
     KeyCollectionMode mode) {

src/debug/debug-scopes.h

@@ -153,6 +153,9 @@ class ScopeIterator {
   void CopyContextLocalsToScopeObject(Handle<ScopeInfo> scope_info,
                                       Handle<Context> context,
                                       Handle<JSObject> scope_object);
+  void CopyModuleVarsToScopeObject(Handle<ScopeInfo> scope_info,
+                                   Handle<Context> context,
+                                   Handle<JSObject> scope_object);
   void CopyContextExtensionToScopeObject(Handle<Context> context,
                                          Handle<JSObject> scope_object,
                                          KeyCollectionMode mode);

src/debug/mirrors.js

@@ -257,6 +257,7 @@ var ScopeType = { Global:  0,
                   Block:   5,
                   Script:  6,
                   Eval:    7,
+                  Module:  8,
                 };
 
 /**

src/objects.h

@@ -4686,6 +4686,14 @@ class ScopeInfo : public FixedArray {
              VariableLocation* location, InitializationFlag* init_flag,
              MaybeAssignedFlag* maybe_assigned_flag);
 
+  // Get metadata of i-th MODULE-allocated variable, where 0 <= i <
+  // ModuleVariableCount.  The metadata is returned via out-arguments, which may
+  // be nullptr if the corresponding information is not requested
+  void ModuleVariable(int i, String** name, int* index,
+                      VariableMode* mode = nullptr,
+                      InitializationFlag* init_flag = nullptr,
+                      MaybeAssignedFlag* maybe_assigned_flag = nullptr);
+
   // Used for the function name variable for named function expressions, and for
   // the receiver.
   enum VariableAllocationInfo { NONE, STACK, CONTEXT, UNUSED };
@@ -4753,14 +4761,19 @@ class ModuleInfoEntry : public FixedArray {
 class ModuleInfo : public FixedArray {
  public:
   DECLARE_CAST(ModuleInfo)
+
   static Handle<ModuleInfo> New(Isolate* isolate, Zone* zone,
                                 ModuleDescriptor* descr);
+
   inline FixedArray* module_requests() const;
   inline FixedArray* special_exports() const;
   inline FixedArray* regular_exports() const;
   inline FixedArray* namespace_imports() const;
   inline FixedArray* regular_imports() const;
 
+  static Handle<ModuleInfoEntry> LookupRegularImport(Handle<ModuleInfo> info,
+                                                     Handle<String> local_name);
+
 #ifdef DEBUG
   inline bool Equals(ModuleInfo* other) const;
 #endif

test/mjsunit/modules-debug-scopes2.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.
+
+// MODULE
+// Flags: --expose-debug-as debug
+
+
+var Debug = debug.Debug;
+
+var test_name;
+var listener_delegate;
+var listener_called;
+var exception;
+var begin_test_count = 0;
+var end_test_count = 0;
+var break_count = 0;
+
+function listener(event, exec_state, event_data, data) {
+  try {
+    if (event == Debug.DebugEvent.Break) {
+      break_count++;
+      listener_called = true;
+      listener_delegate(exec_state);
+    }
+  } catch (e) {
+    exception = e;
+  }
+}
+
+Debug.setListener(listener);
+
+
+function BeginTest(name) {
+  test_name = name;
+  listener_delegate = null;
+  listener_called = false;
+  exception = null;
+  begin_test_count++;
+}
+
+function EndTest() {
+  assertTrue(listener_called, "listener not called for " + test_name);
+  assertNull(exception, test_name + " / " + exception);
+  end_test_count++;
+}
+
+
+// Check that two scope are the same.
+function assertScopeMirrorEquals(scope1, scope2) {
+  assertEquals(scope1.scopeType(), scope2.scopeType());
+  assertEquals(scope1.frameIndex(), scope2.frameIndex());
+  assertEquals(scope1.scopeIndex(), scope2.scopeIndex());
+  assertPropertiesEqual(scope1.scopeObject().value(), scope2.scopeObject().value());
+}
+
+function CheckFastAllScopes(scopes, exec_state)
+{
+  var fast_all_scopes = exec_state.frame().allScopes(true);
+  var length = fast_all_scopes.length;
+  assertTrue(scopes.length >= length);
+  for (var i = 0; i < scopes.length && i < length; i++) {
+    var scope = fast_all_scopes[length - i - 1];
+    assertTrue(scope.isScope());
+    assertEquals(scopes[scopes.length - i - 1], scope.scopeType());
+  }
+}
+
+
+// Check that the scope chain contains the expected types of scopes.
+function CheckScopeChain(scopes, exec_state) {
+  var all_scopes = exec_state.frame().allScopes();
+  assertEquals(scopes.length, exec_state.frame().scopeCount());
+  assertEquals(scopes.length, all_scopes.length, "FrameMirror.allScopes length");
+  for (var i = 0; i < scopes.length; i++) {
+    var scope = exec_state.frame().scope(i);
+    assertTrue(scope.isScope());
+    assertEquals(scopes[i], scope.scopeType());
+    assertScopeMirrorEquals(all_scopes[i], scope);
+  }
+  CheckFastAllScopes(scopes, exec_state);
+
+  // Get the debug command processor.
+  var dcp = exec_state.debugCommandProcessor("unspecified_running_state");
+
+  // Send a scopes request and check the result.
+  var json;
+  var request_json = '{"seq":0,"type":"request","command":"scopes"}';
+  var response_json = dcp.processDebugJSONRequest(request_json);
+  var response = JSON.parse(response_json);
+  assertEquals(scopes.length, response.body.scopes.length);
+  for (var i = 0; i < scopes.length; i++) {
+    assertEquals(i, response.body.scopes[i].index);
+    assertEquals(scopes[i], response.body.scopes[i].type);
+    if (scopes[i] == debug.ScopeType.Local ||
+        scopes[i] == debug.ScopeType.Script ||
+        scopes[i] == debug.ScopeType.Closure) {
+      assertTrue(response.body.scopes[i].object.ref < 0);
+    } else {
+      assertTrue(response.body.scopes[i].object.ref >= 0);
+    }
+    var found = false;
+    for (var j = 0; j < response.refs.length && !found; j++) {
+      found = response.refs[j].handle == response.body.scopes[i].object.ref;
+    }
+    assertTrue(found, "Scope object " + response.body.scopes[i].object.ref + " not found");
+  }
+}
+
+
+function CheckScopeDoesNotHave(properties, number, exec_state) {
+  var scope = exec_state.frame().scope(number);
+  for (var p of properties) {
+    var property_mirror = scope.scopeObject().property(p);
+    assertTrue(property_mirror.isUndefined(), 'property ' + p + ' found in scope');
+  }
+}
+
+
+// Check that the scope contains at least minimum_content. For functions just
+// check that there is a function.
+function CheckScopeContent(minimum_content, number, exec_state) {
+  var scope = exec_state.frame().scope(number);
+  var minimum_count = 0;
+  for (var p in minimum_content) {
+    var property_mirror = scope.scopeObject().property(p);
+    assertFalse(property_mirror.isUndefined(), 'property ' + p + ' not found in scope');
+    if (typeof(minimum_content[p]) === 'function') {
+      assertTrue(property_mirror.value().isFunction());
+    } else {
+      assertEquals(minimum_content[p], property_mirror.value().value(), 'property ' + p + ' has unexpected value');
+    }
+    minimum_count++;
+  }
+
+  // 'arguments' and might be exposed in the local and closure scope. Just
+  // ignore this.
+  var scope_size = scope.scopeObject().properties().length;
+  if (!scope.scopeObject().property('arguments').isUndefined()) {
+    scope_size--;
+  }
+  // Ditto for 'this'.
+  if (!scope.scopeObject().property('this').isUndefined()) {
+    scope_size--;
+  }
+  // Temporary variables introduced by the parser have not been materialized.
+  assertTrue(scope.scopeObject().property('').isUndefined());
+
+  if (scope_size < minimum_count) {
+    print('Names found in scope:');
+    var names = scope.scopeObject().propertyNames();
+    for (var i = 0; i < names.length; i++) {
+      print(names[i]);
+    }
+  }
+  assertTrue(scope_size >= minimum_count);
+
+  // Get the debug command processor.
+  var dcp = exec_state.debugCommandProcessor("unspecified_running_state");
+
+  // Send a scope request for information on a single scope and check the
+  // result.
+  var request_json = '{"seq":0,"type":"request","command":"scope","arguments":{"number":';
+  request_json += scope.scopeIndex();
+  request_json += '}}';
+  var response_json = dcp.processDebugJSONRequest(request_json);
+  var response = JSON.parse(response_json);
+  assertEquals(scope.scopeType(), response.body.type);
+  assertEquals(number, response.body.index);
+  if (scope.scopeType() == debug.ScopeType.Local ||
+      scope.scopeType() == debug.ScopeType.Script ||
+      scope.scopeType() == debug.ScopeType.Closure) {
+    assertTrue(response.body.object.ref < 0);
+  } else {
+    assertTrue(response.body.object.ref >= 0);
+  }
+  var found = false;
+  for (var i = 0; i < response.refs.length && !found; i++) {
+    found = response.refs[i].handle == response.body.object.ref;
+  }
+  assertTrue(found, "Scope object " + response.body.object.ref + " not found");
+}
+
+
+////////////////////////////////////////////////////////////////////////////////
+// Actual tests.
+////////////////////////////////////////////////////////////////////////////////
+
+
+BeginTest();
+listener_delegate = function(exec_state) {
+  CheckScopeChain([debug.ScopeType.Module,
+                   debug.ScopeType.Script,
+                   debug.ScopeType.Global], exec_state);
+  CheckScopeContent(
+      {local_var: undefined, exported_var: undefined, imported_var: undefined},
+      0, exec_state);
+  CheckScopeDoesNotHave(
+      ["doesnotexist", "local_let", "exported_let", "imported_let"],
+      0, exec_state);
+};
+debugger;
+EndTest();
+
+let local_let = 1;
+var local_var = 2;
+export let exported_let = 3;
+export var exported_var = 4;
+import {exported_let as imported_let} from "modules-debug-scopes2.js";
+import {exported_var as imported_var} from "modules-debug-scopes2.js";
+
+BeginTest();
+listener_delegate = function(exec_state) {
+  CheckScopeChain([debug.ScopeType.Module,
+                   debug.ScopeType.Script,
+                   debug.ScopeType.Global], exec_state);
+  CheckScopeContent(
+      {local_let: 1, local_var: 2, exported_let: 3, exported_var: 4,
+       imported_let: 3, imported_var: 4}, 0, exec_state);
+};
+debugger;
+EndTest();
+
+local_let += 10;
+local_var += 10;
+exported_let += 10;
+exported_var += 10;
+
+BeginTest();
+listener_delegate = function(exec_state) {
+  CheckScopeChain([debug.ScopeType.Module,
+                   debug.ScopeType.Script,
+                   debug.ScopeType.Global], exec_state);
+  CheckScopeContent(
+      {local_let: 11, local_var: 12, exported_let: 13, exported_var: 14,
+       imported_let: 13, imported_var: 14}, 0, exec_state);
+};
+debugger;
+EndTest();