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

src/arm64/assembler-arm64.h

 // Copyright 2013 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_ARM64_ASSEMBLER_ARM64_H_
 #define V8_ARM64_ASSEMBLER_ARM64_H_
 
 #include <deque>
 #include <list>
 #include <map>
@@ skipping 875 matching lines @@
                                                FLUSH_ICACHE_IF_NEEDED);
 
   // Return the code target address at a call site from the return address of
   // that call in the instruction stream.
   inline static Address target_address_from_return_address(Address pc);
 
   // Given the address of the beginning of a call, return the address in the
   // instruction stream that call will return from.
   inline static Address return_address_from_call_start(Address pc);
 
-  // Return the code target address of the patch debug break slot
-  inline static Address break_address_from_return_address(Address pc);
-
   // This sets the branch destination (which is in the constant pool on ARM).
   // This is for calls and branches within generated code.
   inline static void deserialization_set_special_target_at(
       Address constant_pool_entry, Code* code, Address target);
 
   // This sets the internal reference at the pc.
   inline static void deserialization_set_target_internal_reference_at(
       Address pc, Address target,
       RelocInfo::Mode mode = RelocInfo::INTERNAL_REFERENCE);
 
@@ skipping 39 matching lines @@
     DCHECK(size >= 0);
     DCHECK(static_cast<uint64_t>(size) == SizeOfCodeGeneratedSince(label));
   }
 
   // Return the number of instructions generated from label to the
   // current position.
   uint64_t InstructionsGeneratedSince(const Label* label) {
     return SizeOfCodeGeneratedSince(label) / kInstructionSize;
   }
 
-  // Number of instructions generated for the return sequence in
-  // FullCodeGenerator::EmitReturnSequence.
-  static const int kJSReturnSequenceInstructions = 7;
-  static const int kJSReturnSequenceLength =
-      kJSReturnSequenceInstructions * kInstructionSize;
-  // Distance between start of patched return sequence and the emitted address
-  // to jump to.
-  static const int kPatchReturnSequenceAddressOffset =  0;
   static const int kPatchDebugBreakSlotAddressOffset =  0;
 
   // Number of instructions necessary to be able to later patch it to a call.
-  // See DebugCodegen::GenerateSlot() and
-  // BreakLocation::SetDebugBreakAtSlot().
-  static const int kDebugBreakSlotInstructions = 4;
+  static const int kDebugBreakSlotInstructions = 5;
   static const int kDebugBreakSlotLength =
     kDebugBreakSlotInstructions * kInstructionSize;
 
-  static const int kPatchDebugBreakSlotReturnOffset = 2 * kInstructionSize;
-
   // Prevent contant pool emission until EndBlockConstPool is called.
   // Call to this function can be nested but must be followed by an equal
   // number of call to EndBlockConstpool.
   void StartBlockConstPool();
 
   // Resume constant pool emission. Need to be called as many time as
   // StartBlockConstPool to have an effect.
   void EndBlockConstPool();
 
   bool is_const_pool_blocked() const;
@@ skipping 28 matching lines @@
   // Debugging ----------------------------------------------------------------
   PositionsRecorder* positions_recorder() { return &positions_recorder_; }
   void RecordComment(const char* msg);
 
   // Record a deoptimization reason that can be used by a log or cpu profiler.
   // Use --trace-deopt to enable.
   void RecordDeoptReason(const int reason, const SourcePosition position);
 
   int buffer_space() const;
 
-  // Mark address of the ExitJSFrame code.
-  void RecordJSReturn();
-
   // Mark generator continuation.
   void RecordGeneratorContinuation();
 
   // Mark address of a debug break slot.
-  void RecordDebugBreakSlot();
-  void RecordDebugBreakSlotForCall(int argc);
-  void RecordDebugBreakSlotForConstructCall();
+  void RecordDebugBreakSlot(RelocInfo::Mode mode, int argc = 0);
 
   // Record the emission of a constant pool.
   //
   // The emission of constant and veneer pools depends on the size of the code
   // generated and the number of RelocInfo recorded.
   // The Debug mechanism needs to map code offsets between two versions of a
   // function, compiled with and without debugger support (see for example
   // Debug::PrepareForBreakPoints()).
   // Compiling functions with debugger support generates additional code
   // (DebugCodegen::GenerateSlot()). This may affect the emission of the pools
@@ skipping 1283 matching lines @@
 class EnsureSpace BASE_EMBEDDED {
  public:
   explicit EnsureSpace(Assembler* assembler) {
     assembler->CheckBufferSpace();
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM64_ASSEMBLER_ARM64_H_