Use a custom Struct for stack trace storage

src/isolate.h

 // Copyright 2012 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.
 
 #ifndef V8_ISOLATE_H_
 #define V8_ISOLATE_H_
 
 #include <memory>
 #include <queue>
 #include <set>
@@ skipping 1451 matching lines @@
   friend v8::StartupData v8::V8::WarmUpSnapshotDataBlob(v8::StartupData,
                                                         const char*);
 
   DISALLOW_COPY_AND_ASSIGN(Isolate);
 };
 
 
 #undef FIELD_ACCESSOR
 #undef THREAD_LOCAL_TOP_ACCESSOR
 
+// Constants for stack trace frames encoded into a fixed array.
+class EncodedStackTraceFrame : public AllStatic {
+ public:
+  static const int kWasmObjectOffset = 0;
+  static const int kWasmFunctionIndexOffset = 1;
+
+  static const int kReceiverOffset = 0;
+  static const int kFunctionOffset = 1;
+
+  static const int kCodeOffset = 2;
+  static const int kOffsetOffset = 3;
+  static const int kFlagsOffset = 4;
+
+  static const int kElementsPerFrame = 5;
+};
 
 class PromiseOnStack {
  public:
   PromiseOnStack(Handle<JSObject> promise, PromiseOnStack* prev)
       : promise_(promise), prev_(prev) {}
   Handle<JSObject> promise() { return promise_; }
   PromiseOnStack* prev() { return prev_; }
 
  private:
   Handle<JSObject> promise_;
@@ skipping 195 matching lines @@
 
   EmbeddedVector<char, 128> filename_;
   FILE* file_;
   int scope_depth_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_ISOLATE_H_