[debug] Untangle DebugInfo from break point support

src/builtins/arm64/builtins-arm64.cc

Index: src/builtins/arm64/builtins-arm64.cc
diff --git a/src/builtins/arm64/builtins-arm64.cc b/src/builtins/arm64/builtins-arm64.cc
index 7e96dc4fb3658f52886ad35af4050a7d753008cf..80d04e847fd96667cfd49e9283a004716fa46996 100644
--- a/src/builtins/arm64/builtins-arm64.cc
+++ b/src/builtins/arm64/builtins-arm64.cc
@@ -1074,14 +1074,12 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
 
   // 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;
   __ Ldr(x0, FieldMemOperand(x1, JSFunction::kSharedFunctionInfoOffset));
-  Register debug_info = kInterpreterBytecodeArrayRegister;
-  Label load_debug_bytecode_array, bytecode_array_loaded;
-  DCHECK(!debug_info.is(x0));
-  __ Ldr(debug_info, FieldMemOperand(x0, SharedFunctionInfo::kDebugInfoOffset));
-  __ JumpIfNotSmi(debug_info, &load_debug_bytecode_array);
   __ Ldr(kInterpreterBytecodeArrayRegister,
          FieldMemOperand(x0, SharedFunctionInfo::kFunctionDataOffset));
+  __ Ldr(x11, FieldMemOperand(x0, SharedFunctionInfo::kDebugInfoOffset));
+  __ JumpIfNotSmi(x11, &maybe_load_debug_bytecode_array);
   __ Bind(&bytecode_array_loaded);
 
   // Check whether we should continue to use the interpreter.
@@ -1170,10 +1168,16 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
   LeaveInterpreterFrame(masm, x2);
   __ Ret();
 
-  // Load debug copy of the bytecode array.
-  __ Bind(&load_debug_bytecode_array);
+  // Load debug copy of the bytecode array if it exists.
+  // kInterpreterBytecodeArrayRegister is already loaded with
+  // SharedFunctionInfo::kFunctionDataOffset.
+  __ Bind(&maybe_load_debug_bytecode_array);
+  __ Ldr(x10, FieldMemOperand(x11, DebugInfo::kFlagsOffset));
+  __ SmiUntag(x10);
+  __ TestAndBranchIfAllClear(x10, DebugInfo::kHasBreakInfo,
+                             &bytecode_array_loaded);
   __ Ldr(kInterpreterBytecodeArrayRegister,
-         FieldMemOperand(debug_info, DebugInfo::kDebugBytecodeArrayIndex));
+         FieldMemOperand(x11, DebugInfo::kDebugBytecodeArrayOffset));
   __ B(&bytecode_array_loaded);
 
   // If the shared code is no longer this entry trampoline, then the underlying