nodejs · mmarchini · Oct 7, 2019 · Oct 3, 2019 · Oct 7, 2019 · Oct 8, 2019
diff --git a/.github/workflows/push.yml b/.github/workflows/push.yml
@@ -16,9 +16,8 @@ jobs:
       fail-fast: false
       matrix:
         node:
-          - version: 8.x
           - version: 10.x
-          - version: 11.x
+          - version: 12.x
           - version: 14.x
             mirror: https://nodejs.org/download/nightly
           - version: 14.x

diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "llnode",
-  "version": "2.2.0",
+  "version": "3.0.0",
   "description": "An lldb plugin for Node.js and V8, which enables inspection of JavaScript states for insights into Node.js processes and their core dumps.",
   "main": "index.js",
   "directories": {

diff --git a/src/constants.h b/src/constants.h
@@ -48,8 +48,6 @@ class Constant {
 
   inline std::string name() { return name_; }
 
- protected:
-  friend class Constants;
   explicit Constant(T value) : value_(value), status_(kValid), name_("") {}
   Constant(T value, std::string name)
       : value_(value), status_(kLoaded), name_(name) {}

diff --git a/src/llscan.cc b/src/llscan.cc
@@ -1563,7 +1563,7 @@ bool FindJSObjectsVisitor::MapCacheEntry::Load(v8::Map map,
   if (is_histogram) type_name = heap_object.GetTypeName(err);
 
   v8::HeapObject descriptors_obj = map.InstanceDescriptors(err);
-  if (err.Fail()) return false;
+  RETURN_IF_INVALID(descriptors_obj, false);
 
   v8::DescriptorArray descriptors(descriptors_obj);
   own_descriptors_count_ = map.NumberOfOwnDescriptors(err);
@@ -1579,8 +1579,8 @@ bool FindJSObjectsVisitor::MapCacheEntry::Load(v8::Map map,
   }
 
   for (uint64_t i = 0; i < own_descriptors_count_; i++) {
-    v8::Value key = descriptors.GetKey(i, err);
-    if (err.Fail()) continue;
+    v8::Value key = descriptors.GetKey(i);
+    if (!key.Check()) continue;
     properties_.emplace_back(key.ToString(err));
   }
 

diff --git a/src/llv8-constants.cc b/src/llv8-constants.cc
@@ -95,6 +95,7 @@ void Map::Load() {
                    "class_Map__constructor__Object");
   kInstanceDescriptorsOffset = LoadConstant({
       "class_Map__instance_descriptors__DescriptorArray",
+      "class_Map__instance_descriptors_offset",
   });
   kBitField3Offset =
       LoadConstant("class_Map__bit_field3__int", "class_Map__bit_field3__SMI");
@@ -322,18 +323,22 @@ void TwoByteString::Load() {
 
 
 void ConsString::Load() {
-  kFirstOffset = LoadConstant("class_ConsString__first__String");
-  kSecondOffset = LoadConstant("class_ConsString__second__String");
+  kFirstOffset = LoadConstant({"class_ConsString__first__String",
+                               "class_ConsString__first_offset__int"});
+  kSecondOffset = LoadConstant({"class_ConsString__second__String",
+                                "class_ConsString__second_offset__int"});
 }
 
 
 void SlicedString::Load() {
   kParentOffset = LoadConstant("class_SlicedString__parent__String");
-  kOffsetOffset = LoadConstant("class_SlicedString__offset__SMI");
+  kOffsetOffset = LoadConstant({"class_SlicedString__offset__SMI",
+                                "class_SlicedString__offset_offset__int"});
 }
 
 void ThinString::Load() {
-  kActualOffset = LoadConstant("class_ThinString__actual__String");
+  kActualOffset = LoadConstant({"class_ThinString__actual__String",
+                                "class_ThinString__actual_offset__int"});
 }
 
 void FixedArrayBase::Load() {
@@ -347,12 +352,26 @@ void FixedArray::Load() {
 
 
 void FixedTypedArrayBase::Load() {
+  kBasePointerOffset = LoadOptionalConstant(
+      {"class_FixedTypedArrayBase__base_pointer__Object"}, 0);
+  kExternalPointerOffset = LoadOptionalConstant(
+      {"class_FixedTypedArrayBase__external_pointer__Object",
+       "class_FixedTypedArrayBase__external_pointer__uintptr_t"},
+      0);
+}
+
+void JSTypedArray::Load() {
   kBasePointerOffset =
-      LoadConstant("class_FixedTypedArrayBase__base_pointer__Object");
-  kExternalPointerOffset =
-      LoadConstant("class_FixedTypedArrayBase__external_pointer__Object");
+      LoadOptionalConstant({"class_JSTypedArray__base_pointer__Object"}, 0);
+  kExternalPointerOffset = LoadOptionalConstant(
+      {"class_JSTypedArray__external_pointer__uintptr_t"}, 0);
 }
 
+// TODO(mmarchini): proper validation so that we log an error if neither classes
+// were able to load their constants.
+bool JSTypedArray::IsDataPointerInJSTypedArray() {
+  return kBasePointerOffset.Loaded() && kExternalPointerOffset.Loaded();
+}
 
 void Oddball::Load() {
   kKindOffset = LoadConstant("class_Oddball__kind_offset__int");
@@ -369,19 +388,15 @@ void Oddball::Load() {
 
 void JSArrayBuffer::Load() {
   kBackingStoreOffset =
-      LoadConstant("class_JSArrayBuffer__backing_store__Object");
-  kByteLengthOffset = LoadConstant("class_JSArrayBuffer__byte_length__Object");
-
-  // v4 compatibility fix
-  if (kBackingStoreOffset == -1) {
-    common_->Load();
+      LoadConstant({"class_JSArrayBuffer__backing_store__Object",
+                    "class_JSArrayBuffer__backing_store__uintptr_t"});
+  kByteLengthOffset =
+      LoadConstant({"class_JSArrayBuffer__byte_length__Object",
+                    "class_JSArrayBuffer__byte_length__size_t"});
 
-    kBackingStoreOffset = kByteLengthOffset + common_->kPointerSize;
+  if (kBackingStoreOffset.Check()) {
   }
 
-  kBitFieldOffset = kBackingStoreOffset + common_->kPointerSize;
-  if (common_->kPointerSize == 8) kBitFieldOffset += 4;
-
   kWasNeuteredMask = LoadConstant("jsarray_buffer_was_neutered_mask");
   kWasNeuteredShift = LoadConstant("jsarray_buffer_was_neutered_shift");
 
@@ -393,19 +408,45 @@ void JSArrayBuffer::Load() {
 }
 
 
+bool JSArrayBuffer::IsByteLengthScalar() {
+  return kByteLengthOffset.name() ==
+         "v8dbg_class_JSArrayBuffer__byte_length__size_t";
+}
+
+Constant<int64_t> JSArrayBuffer::BitFieldOffset() {
+  if (!kBackingStoreOffset.Check()) return Constant<int64_t>();
+
+  common_->Load();
+  int64_t kBitFieldOffset = *kBackingStoreOffset + common_->kPointerSize;
+  if (common_->kPointerSize == 8) kBitFieldOffset += 4;
+  return Constant<int64_t>(kBitFieldOffset);
+}
+
+
 void JSArrayBufferView::Load() {
   kBufferOffset = LoadConstant("class_JSArrayBufferView__buffer__Object");
   kByteOffsetOffset =
-      LoadConstant("class_JSArrayBufferView__raw_byte_offset__Object");
+      LoadConstant({"class_JSArrayBufferView__raw_byte_offset__Object",
+                    "class_JSArrayBufferView__byte_offset__size_t"});
   kByteLengthOffset =
-      LoadConstant("class_JSArrayBufferView__raw_byte_length__Object");
+      LoadConstant({"class_JSArrayBufferView__raw_byte_length__Object",
+                    "class_JSArrayBufferView__byte_length__size_t"});
 }
 
+bool JSArrayBufferView::IsByteLengthScalar() {
+  return kByteLengthOffset.name() ==
+         "v8dbg_class_JSArrayBufferView__byte_length__size_t";
+}
+
+bool JSArrayBufferView::IsByteOffsetScalar() {
+  return kByteOffsetOffset.name() ==
+         "v8dbg_class_JSArrayBufferView__byte_offset__size_t";
+}
 
 void DescriptorArray::Load() {
-  kDetailsOffset = LoadConstant("prop_desc_details");
-  kKeyOffset = LoadConstant("prop_desc_key");
-  kValueOffset = LoadConstant("prop_desc_value");
+  kDetailsOffset = LoadConstant({"prop_desc_details"});
+  kKeyOffset = LoadConstant({"prop_desc_key"});
+  kValueOffset = LoadConstant({"prop_desc_value"});
 
   kPropertyIndexMask = LoadConstant("prop_index_mask");
   kPropertyIndexShift = LoadConstant("prop_index_shift");
@@ -455,8 +496,12 @@ void DescriptorArray::Load() {
     kRepresentationDouble = 7;
   }
 
-  kFirstIndex = LoadConstant("prop_idx_first");
-  kSize = LoadConstant("prop_desc_size");
+  // NOTE(mmarchini): removed from V8 7.2.
+  // https://github.com/v8/v8/commit/1ad0cd5
+  kFirstIndex = LoadOptionalConstant({"prop_idx_first"}, 0);
+  kSize = LoadConstant({"prop_desc_size"});
+  kHeaderSize = LoadOptionalConstant(
+      {"class_DescriptorArray__header_size__uintptr_t"}, 24);
 }
 
 
@@ -505,7 +550,24 @@ void Frame::Load() {
 
 
 void Symbol::Load() {
-  kNameOffset = LoadConstant("class_Symbol__name__Object");
+  // map is the last field of HeapObject
+  Constant<int64_t> maybe_name_offset =
+      LoadConstant({"class_HeapObject__map__Map"});
+  common_->Load();
+  if (maybe_name_offset.Check()) {
+    int name_offset = *maybe_name_offset;
+
+    name_offset += common_->kPointerSize;
+    // class Name extends HeapObject and has only one uint32 field
+    name_offset += sizeof(uint32_t);
+    // class Symbol extends Name and has one int32 field before name
+    name_offset += sizeof(int32_t);
+
+    kNameOffset =
+        LoadOptionalConstant({"class_Symbol__name__Object"}, name_offset);
+  } else {
+    kNameOffset = LoadConstant({"class_Symbol__name__Object"});
+  }
 }
 
 

diff --git a/src/llv8-constants.h b/src/llv8-constants.h
@@ -296,8 +296,8 @@ class ConsString : public Module {
  public:
   CONSTANTS_DEFAULT_METHODS(ConsString);
 
-  int64_t kFirstOffset;
-  int64_t kSecondOffset;
+  Constant<int64_t> kFirstOffset;
+  Constant<int64_t> kSecondOffset;
 
  protected:
   void Load();
@@ -308,7 +308,7 @@ class SlicedString : public Module {
   CONSTANTS_DEFAULT_METHODS(SlicedString);
 
   int64_t kParentOffset;
-  int64_t kOffsetOffset;
+  Constant<int64_t> kOffsetOffset;
 
  protected:
   void Load();
@@ -318,7 +318,7 @@ class ThinString : public Module {
  public:
   CONSTANTS_DEFAULT_METHODS(ThinString);
 
-  int64_t kActualOffset;
+  Constant<int64_t> kActualOffset;
 
  protected:
   void Load();
@@ -348,8 +348,21 @@ class FixedTypedArrayBase : public Module {
  public:
   CONSTANTS_DEFAULT_METHODS(FixedTypedArrayBase);
 
-  int64_t kBasePointerOffset;
-  int64_t kExternalPointerOffset;
+  Constant<int64_t> kBasePointerOffset;
+  Constant<int64_t> kExternalPointerOffset;
+
+ protected:
+  void Load();
+};
+
+class JSTypedArray : public Module {
+ public:
+  CONSTANTS_DEFAULT_METHODS(JSTypedArray);
+
+  Constant<int64_t> kBasePointerOffset;
+  Constant<int64_t> kExternalPointerOffset;
+
+  bool IsDataPointerInJSTypedArray();
 
  protected:
   void Load();
@@ -379,13 +392,15 @@ class JSArrayBuffer : public Module {
 
   int64_t kKindOffset;
 
-  int64_t kBackingStoreOffset;
-  int64_t kByteLengthOffset;
-  int64_t kBitFieldOffset;
+  Constant<int64_t> kBackingStoreOffset;
+  Constant<int64_t> kByteLengthOffset;
 
   int64_t kWasNeuteredMask;
   int64_t kWasNeuteredShift;
 
+  Constant<int64_t> BitFieldOffset();
+  bool IsByteLengthScalar();
+
  protected:
   void Load();
 };
@@ -395,8 +410,11 @@ class JSArrayBufferView : public Module {
   CONSTANTS_DEFAULT_METHODS(JSArrayBufferView);
 
   int64_t kBufferOffset;
-  int64_t kByteOffsetOffset;
-  int64_t kByteLengthOffset;
+  Constant<int64_t> kByteOffsetOffset;
+  Constant<int64_t> kByteLengthOffset;
+
+  bool IsByteLengthScalar();
+  bool IsByteOffsetScalar();
 
  protected:
   void Load();
@@ -406,9 +424,9 @@ class DescriptorArray : public Module {
  public:
   CONSTANTS_DEFAULT_METHODS(DescriptorArray);
 
-  int64_t kDetailsOffset;
-  int64_t kKeyOffset;
-  int64_t kValueOffset;
+  Constant<int64_t> kDetailsOffset;
+  Constant<int64_t> kKeyOffset;
+  Constant<int64_t> kValueOffset;
 
   int64_t kPropertyIndexMask;
   int64_t kPropertyIndexShift;
@@ -417,8 +435,10 @@ class DescriptorArray : public Module {
 
   int64_t kRepresentationDouble;
 
-  int64_t kFirstIndex;
-  int64_t kSize;
+  Constant<int64_t> kFirstIndex;
+  Constant<int64_t> kHeaderSize;
+  Constant<int64_t> kSize;
+  Constant<int64_t> kEntrySize;
 
   // node.js <= 7
   int64_t kPropertyTypeMask = -1;
@@ -489,7 +509,7 @@ class Symbol : public Module {
  public:
   CONSTANTS_DEFAULT_METHODS(Symbol);
 
-  int64_t kNameOffset;
+  Constant<int64_t> kNameOffset;
 
  protected:
   void Load();