Debugger: use debug break slots to break at function exit.

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 352 matching lines @@
     // Please note the order is important (see IsCodeTarget, IsGCRelocMode).
     CODE_TARGET,  // Code target which is not any of the above.
     CODE_TARGET_WITH_ID,
     CONSTRUCT_CALL,  // code target that is a call to a JavaScript constructor.
     DEBUGGER_STATEMENT,  // Code target for the debugger statement.
     EMBEDDED_OBJECT,
     CELL,
 
     // Everything after runtime_entry (inclusive) is not GC'ed.
     RUNTIME_ENTRY,
-    JS_RETURN,  // Marks start of the ExitJSFrame code.
     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_CONSTRUCT_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.
@@ skipping 45 matching lines @@
     return mode == EMBEDDED_OBJECT;
   }
   static inline bool IsCell(Mode mode) { return mode == CELL; }
   static inline bool IsRuntimeEntry(Mode mode) {
     return mode == RUNTIME_ENTRY;
   }
   // Is the relocation mode affected by GC?
   static inline bool IsGCRelocMode(Mode mode) {
     return mode <= LAST_GCED_ENUM;
   }
-  static inline bool IsJSReturn(Mode mode) {
-    return mode == JS_RETURN;
-  }
   static inline bool IsComment(Mode mode) {
     return mode == COMMENT;
   }
   static inline bool IsConstPool(Mode mode) {
     return mode == CONST_POOL;
   }
   static inline bool IsVeneerPool(Mode mode) {
     return mode == VENEER_POOL;
   }
   static inline bool IsDeoptReason(Mode mode) {
     return mode == DEOPT_REASON;
   }
   static inline bool IsPosition(Mode mode) {
     return mode == POSITION || mode == STATEMENT_POSITION;
   }
   static inline bool IsStatementPosition(Mode mode) {
     return mode == STATEMENT_POSITION;
   }
   static inline bool IsExternalReference(Mode mode) {
     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) || IsDebugBreakSlotAtCall(mode) ||
+    return IsDebugBreakSlotAtPosition(mode) || IsDebugBreakSlotAtReturn(mode) ||
+           IsDebugBreakSlotAtCall(mode) ||
            IsDebugBreakSlotAtConstructCall(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 IsDebugBreakSlotAtConstructCall(Mode mode) {
     return mode == DEBUG_BREAK_SLOT_AT_CONSTRUCT_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) {
     return mode == GENERATOR_CONTINUATION;
   }
   static inline int ModeMask(Mode mode) { return 1 << mode; }
 
   // Accessors
   byte* pc() const { return pc_; }
   void set_pc(byte* pc) { pc_ = pc; }
   Mode rmode() const {  return rmode_; }
   intptr_t data() const { return data_; }
   Code* host() const { return host_; }
   void set_host(Code* host) { host_ = host; }
 
-  // Apply a relocation by delta bytes
+  // Apply a relocation by delta bytes. When the code object is moved, PC
+  // relative addresses have to be updated as well as absolute addresses
+  // inside the code (internal references).
   INLINE(void apply(intptr_t delta,
                     ICacheFlushMode icache_flush_mode =
                         FLUSH_ICACHE_IF_NEEDED));
 
   // Is the pointer this relocation info refers to coded like a plain pointer
   // or is it strange in some way (e.g. relative or patched into a series of
   // instructions).
   bool IsCodedSpecially();
 
   // If true, the pointer this relocation info refers to is an entry in the
@@ skipping 68 matching lines @@
   // applies to; can only be called if rmode_ is INTERNAL_REFERENCE.
   INLINE(Address target_internal_reference());
 
   // Return the reference address this relocation applies to;
   // can only be called if rmode_ is INTERNAL_REFERENCE.
   INLINE(Address target_internal_reference_address());
 
   // Read/modify the address of a call instruction. This is used to relocate
   // the break points where straight-line code is patched with a call
   // instruction.
-  INLINE(Address call_address());
-  INLINE(void set_call_address(Address target));
-  INLINE(Object* call_object());
-  INLINE(void set_call_object(Object* target));
-  INLINE(Object** call_object_address());
+  INLINE(Address debug_call_address());
+  INLINE(void set_debug_call_address(Address target));
 
   // Wipe out a relocation to a fixed value, used for making snapshots
   // reproducible.
   INLINE(void WipeOut());
 
   template<typename StaticVisitor> inline void Visit(Heap* heap);
   inline void Visit(Isolate* isolate, ObjectVisitor* v);
 
   // Patch the code with a call.
   void PatchCodeWithCall(Address target, int guard_bytes);
@@ skipping 19 matching lines @@
 #endif  // ENABLE_DISASSEMBLER
 #ifdef VERIFY_HEAP
   void Verify(Isolate* isolate);
 #endif
 
   static const int kCodeTargetMask = (1 << (LAST_CODE_ENUM + 1)) - 1;
   static const int kPositionMask = 1 << POSITION | 1 << STATEMENT_POSITION;
   static const int kDataMask =
       (1 << CODE_TARGET_WITH_ID) | kPositionMask | (1 << COMMENT);
   static const int kDebugBreakSlotMask =
-      1 << DEBUG_BREAK_SLOT_AT_POSITION | 1 << DEBUG_BREAK_SLOT_AT_CALL |
-      1 << DEBUG_BREAK_SLOT_AT_CONSTRUCT_CALL;
-  static const int kApplyMask;  // Modes affected by apply. Depends on arch.
+      1 << DEBUG_BREAK_SLOT_AT_POSITION | 1 << DEBUG_BREAK_SLOT_AT_RETURN |
+      1 << DEBUG_BREAK_SLOT_AT_CALL | 1 << DEBUG_BREAK_SLOT_AT_CONSTRUCT_CALL;
+  static const int kApplyMask;  // Modes affected by apply.  Depends on arch.
 
  private:
   // On ARM, note that pc_ is the address of the constant pool entry
   // to be relocated and not the address of the instruction
   // referencing the constant pool entry (except when rmode_ ==
   // comment).
   byte* pc_;
   Mode rmode_;
   intptr_t data_;
   Code* host_;
@@ skipping 614 matching lines @@
   };
 
   Label emitted_label_;  // Records pc_offset of emitted pool
   PerTypeEntryInfo info_[ConstantPoolEntry::NUMBER_OF_TYPES];
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ASSEMBLER_H_