[debug] Untangle DebugInfo from break point support

src/builtins/x64/builtins-x64.cc

 // Copyright 2012 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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/code-factory.h"
 #include "src/codegen.h"
 #include "src/counters.h"
 #include "src/deoptimizer.h"
@@ skipping 770 matching lines @@
   __ movp(rbx, FieldOperand(rdi, JSFunction::kFeedbackVectorOffset));
   __ movp(rbx, FieldOperand(rbx, Cell::kValueOffset));
   __ movp(rbx,
           FieldOperand(rbx, FeedbackVector::kOptimizedCodeIndex * kPointerSize +
                                 FeedbackVector::kHeaderSize));
   __ movp(optimized_code_entry, FieldOperand(rbx, WeakCell::kValueOffset));
   __ JumpIfNotSmi(optimized_code_entry, &switch_to_optimized_code);
 
   // Get the bytecode array from the function object (or from the DebugInfo if
   // it is present) and load it into kInterpreterBytecodeArrayRegister.
+  Label maybe_load_debug_bytecode_array, bytecode_array_loaded;
   __ movp(rax, FieldOperand(rdi, JSFunction::kSharedFunctionInfoOffset));
-  Label load_debug_bytecode_array, bytecode_array_loaded;
-  __ JumpIfNotSmi(FieldOperand(rax, SharedFunctionInfo::kDebugInfoOffset),
-                  &load_debug_bytecode_array);
   __ movp(kInterpreterBytecodeArrayRegister,
           FieldOperand(rax, SharedFunctionInfo::kFunctionDataOffset));
+  __ JumpIfNotSmi(FieldOperand(rax, SharedFunctionInfo::kDebugInfoOffset),
+                  &maybe_load_debug_bytecode_array);
   __ bind(&bytecode_array_loaded);
 
   // Check whether we should continue to use the interpreter.
   // TODO(rmcilroy) Remove self healing once liveedit only has to deal with
   // Ignition bytecode.
   Label switch_to_different_code_kind;
   __ Move(rcx, masm->CodeObject());  // Self-reference to this code.
   __ cmpp(rcx, FieldOperand(rax, SharedFunctionInfo::kCodeOffset));
   __ j(not_equal, &switch_to_different_code_kind);
 
@@ skipping 67 matching lines @@
                           kInterpreterBytecodeOffsetRegister, times_1, 0));
   __ movp(rbx, Operand(kInterpreterDispatchTableRegister, rbx,
                        times_pointer_size, 0));
   __ call(rbx);
   masm->isolate()->heap()->SetInterpreterEntryReturnPCOffset(masm->pc_offset());
 
   // The return value is in rax.
   LeaveInterpreterFrame(masm, rbx, rcx);
   __ ret(0);
 
-  // Load debug copy of the bytecode array.
-  __ bind(&load_debug_bytecode_array);
-  Register debug_info = kInterpreterBytecodeArrayRegister;
-  __ movp(debug_info, FieldOperand(rax, SharedFunctionInfo::kDebugInfoOffset));
+  // Load debug copy of the bytecode array if it exists.
+  // kInterpreterBytecodeArrayRegister is already loaded with
+  // SharedFunctionInfo::kFunctionDataOffset.
+  __ bind(&maybe_load_debug_bytecode_array);
+  __ movp(rcx, FieldOperand(rax, SharedFunctionInfo::kDebugInfoOffset));
+  __ SmiToInteger32(kScratchRegister,
+                    FieldOperand(rcx, DebugInfo::kFlagsOffset));
+  __ testl(kScratchRegister, Immediate(DebugInfo::kHasBreakInfo));
+  __ j(zero, &bytecode_array_loaded);
   __ movp(kInterpreterBytecodeArrayRegister,
-          FieldOperand(debug_info, DebugInfo::kDebugBytecodeArrayIndex));
+          FieldOperand(rcx, DebugInfo::kDebugBytecodeArrayOffset));
   __ jmp(&bytecode_array_loaded);
 
   // If the shared code is no longer this entry trampoline, then the underlying
   // function has been switched to a different kind of code and we heal the
   // closure by switching the code entry field over to the new code as well.
   __ bind(&switch_to_different_code_kind);
   __ leave();  // Leave the frame so we can tail call.
   __ movp(rcx, FieldOperand(rdi, JSFunction::kSharedFunctionInfoOffset));
   __ movp(rcx, FieldOperand(rcx, SharedFunctionInfo::kCodeOffset));
   __ leap(rcx, FieldOperand(rcx, Code::kHeaderSize));
@@ skipping 2335 matching lines @@
   // Now jump to the instructions of the returned code object.
   __ jmp(r11);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64