[coverage] Block coverage with support for IfStatements

src/objects/debug-objects.h

 // 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.
 
 #ifndef V8_OBJECTS_DEBUG_OBJECTS_H_
 #define V8_OBJECTS_DEBUG_OBJECTS_H_
 
 #include "src/objects.h"
 
 // Has to be the last include (doesn't have include guards):
@@ skipping 56 matching lines @@
   // Get the number of break points for this function.
   int GetBreakPointCount();
 
   inline bool HasDebugBytecodeArray();
   inline bool HasDebugCode();
 
   inline BytecodeArray* OriginalBytecodeArray();
   inline BytecodeArray* DebugBytecodeArray();
   inline Code* DebugCode();
 
+  // --- Block Coverage ---
+  // ----------------------
+
+  bool HasCoverageInfo() const;
+
+  // Clears all fields related to block coverage. Returns true iff the
+  // DebugInfo is now empty.
+  bool ClearCoverageInfo();
+  DECL_ACCESSORS(coverage_info, Object)
+
   DECLARE_CAST(DebugInfo)
 
   // Dispatched behavior.
   DECLARE_PRINTER(DebugInfo)
   DECLARE_VERIFIER(DebugInfo)
 
   static const int kSharedFunctionInfoOffset = Struct::kHeaderSize;
   static const int kDebuggerHintsOffset =
       kSharedFunctionInfoOffset + kPointerSize;
   static const int kDebugBytecodeArrayOffset =
       kDebuggerHintsOffset + kPointerSize;
   static const int kBreakPointsStateOffset =
       kDebugBytecodeArrayOffset + kPointerSize;
   static const int kFlagsOffset = kBreakPointsStateOffset + kPointerSize;
-  static const int kSize = kFlagsOffset + kPointerSize;
+  static const int kCoverageInfoOffset = kFlagsOffset + kPointerSize;
+  static const int kSize = kCoverageInfoOffset + kPointerSize;
 
   static const int kEstimatedNofBreakPointsInFunction = 4;
 
  private:
   // Get the break point info object for a source position.
   Object* GetBreakPointInfo(int source_position);
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(DebugInfo);
 };
 
@@ skipping 23 matching lines @@
 
   DECLARE_CAST(BreakPointInfo)
 
   static const int kSourcePositionOffset = kValue1Offset;
   static const int kBreakPointObjectsOffset = kValue2Offset;
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(BreakPointInfo);
 };
 
+// Holds information related to block code coverage.
+// More information at go/v8-designdoc-block-code-coverage.

[Michael Starzinger, 2017/06/06 11:49:32]

nit: Likewise, no "go" links.

[jgruber, 2017/06/06 14:52:46]

Done.

+class CoverageInfo : public FixedArray {
+ public:
+  int SlotCount() const;
+
+  int StartSourcePosition(int slot_index) const;
+  int EndSourcePosition(int slot_index) const;
+  int BlockCount(int slot_index) const;
+
+  void InitializeSlot(int slot_index, int start_pos, int end_pos);
+  void IncrementBlockCount(int slot_index);
+
+  static int FixedArrayLengthForSlotCount(int slot_count) {
+    return slot_count * kSlotIndexCount + kFirstSlotIndex;
+  }
+
+  DECLARE_CAST(CoverageInfo)
+
+ private:
+  static int FirstIndexForSlot(int slot_index) {
+    return kFirstSlotIndex + slot_index * kSlotIndexCount;
+  }
+
+  static const int kFirstSlotIndex = 0;
+
+  // Each slot is assigned a group of indices starting at kFirstSlotIndex.
+  // Within this group, semantics are as follows:
+  static const int kSlotStartSourcePositionIndex = 0;
+  static const int kSlotEndSourcePositionIndex = 1;
+  static const int kSlotBlockCountIndex = 2;
+  static const int kSlotIndexCount = 3;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(CoverageInfo);
+};
+
 }  // namespace internal
 }  // namespace v8
 
 #include "src/objects/object-macros-undef.h"
 
 #endif  // V8_OBJECTS_DEBUG_OBJECTS_H_