Assign unique IDs to FunctionLiterals

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index c59beab8be3d72eeb8afc87ffdc603771eec6749..6d10a00eaf73bc6053389372f3db5f5157f19eea 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -7473,6 +7473,12 @@ class SharedFunctionInfo: public HeapObject {
   // available.
   DECL_ACCESSORS(feedback_metadata, TypeFeedbackMetadata)
 
+  // [function_literal_num] - uniquely identifies the FunctionLiteral this
+  // SharedFunctionInfo represents within its script, or -1 if this
+  // SharedFunctionInfo object doesn't correspond to a parsed FunctionLiteral.
+  inline int function_literal_num() const;
+  inline void set_function_literal_num(int value);
+
 #if TRACE_MAPS
   // [unique_id] - For --trace-maps purposes, an identifier that's persistent
   // even if the GC moves this SharedFunctionInfo.
@@ -7779,13 +7785,15 @@ class SharedFunctionInfo: public HeapObject {
   static const int kFunctionIdentifierOffset = kDebugInfoOffset + kPointerSize;
   static const int kFeedbackMetadataOffset =
       kFunctionIdentifierOffset + kPointerSize;
+  static const int kFunctionLiteralNumOffset =
+      kFeedbackMetadataOffset + kPointerSize;
 #if TRACE_MAPS
-  static const int kUniqueIdOffset = kFeedbackMetadataOffset + kPointerSize;
+  static const int kUniqueIdOffset = kFunctionLiteralNumOffset + kPointerSize;
   static const int kLastPointerFieldOffset = kUniqueIdOffset;
 #else
   // Just to not break the postmortrem support with conditional offsets
-  static const int kUniqueIdOffset = kFeedbackMetadataOffset;
-  static const int kLastPointerFieldOffset = kFeedbackMetadataOffset;
+  static const int kUniqueIdOffset = kFunctionLiteralNumOffset;
+  static const int kLastPointerFieldOffset = kFunctionLiteralNumOffset;
 #endif
 
 #if V8_HOST_ARCH_32_BIT