[debugger] fix step-next for tail calls.

src/assembler.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 380 matching lines @@
     // Everything after runtime_entry (inclusive) is not GC'ed.
     RUNTIME_ENTRY,
     COMMENT,
     POSITION,            // See comment for kNoPosition above.
     STATEMENT_POSITION,  // See comment for kNoPosition above.
 
     // Additional code inserted for debug break slot.
     DEBUG_BREAK_SLOT_AT_POSITION,
     DEBUG_BREAK_SLOT_AT_RETURN,
     DEBUG_BREAK_SLOT_AT_CALL,
+    DEBUG_BREAK_SLOT_AT_TAIL_CALL,
 
     EXTERNAL_REFERENCE,  // The address of an external C++ function.
     INTERNAL_REFERENCE,  // An address inside the same function.
 
     // Encoded internal reference, used only on MIPS, MIPS64 and PPC.
     INTERNAL_REFERENCE_ENCODED,
 
     // Continuation points for a generator yield.
     GENERATOR_CONTINUATION,
 
@@ skipping 73 matching lines @@
     return mode == EXTERNAL_REFERENCE;
   }
   static inline bool IsInternalReference(Mode mode) {
     return mode == INTERNAL_REFERENCE;
   }
   static inline bool IsInternalReferenceEncoded(Mode mode) {
     return mode == INTERNAL_REFERENCE_ENCODED;
   }
   static inline bool IsDebugBreakSlot(Mode mode) {
     return IsDebugBreakSlotAtPosition(mode) || IsDebugBreakSlotAtReturn(mode) ||
-           IsDebugBreakSlotAtCall(mode);
+           IsDebugBreakSlotAtCall(mode) || IsDebugBreakSlotAtTailCall(mode);
   }
   static inline bool IsDebugBreakSlotAtPosition(Mode mode) {
     return mode == DEBUG_BREAK_SLOT_AT_POSITION;
   }
   static inline bool IsDebugBreakSlotAtReturn(Mode mode) {
     return mode == DEBUG_BREAK_SLOT_AT_RETURN;
   }
   static inline bool IsDebugBreakSlotAtCall(Mode mode) {
     return mode == DEBUG_BREAK_SLOT_AT_CALL;
   }
+  static inline bool IsDebugBreakSlotAtTailCall(Mode mode) {
+    return mode == DEBUG_BREAK_SLOT_AT_TAIL_CALL;
+  }
   static inline bool IsDebuggerStatement(Mode mode) {
     return mode == DEBUGGER_STATEMENT;
   }
   static inline bool IsNone(Mode mode) {
     return mode == NONE32 || mode == NONE64;
   }
   static inline bool IsCodeAgeSequence(Mode mode) {
     return mode == CODE_AGE_SEQUENCE;
   }
   static inline bool IsGeneratorContinuation(Mode mode) {
@@ skipping 800 matching lines @@
     std::vector<ConstantPoolEntry> shared_entries;
   };
 
   Label emitted_label_;  // Records pc_offset of emitted pool
   PerTypeEntryInfo info_[ConstantPoolEntry::NUMBER_OF_TYPES];
 };
 
 }  // namespace internal
 }  // namespace v8
 #endif  // V8_ASSEMBLER_H_