[interpreter, debugger] support debug breaks via bytecode array copy

src/mips/builtins-mips.cc

Index: src/mips/builtins-mips.cc
diff --git a/src/mips/builtins-mips.cc b/src/mips/builtins-mips.cc
index 9b79da73fbbc772fc32666de3e94fa408ae042f0..281dc62c6b498ef8a0d28b3800862bcf89142b2d 100644
--- a/src/mips/builtins-mips.cc
+++ b/src/mips/builtins-mips.cc
@@ -854,8 +854,15 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
   // Get the bytecode array from the function object and load the pointer to the
   // first entry into kInterpreterBytecodeRegister.
   __ lw(a0, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
+  Label load_debug_bytecode_array, bytecode_array_loaded;
+  Register debug_info = kInterpreterBytecodeArrayRegister;
+  DCHECK(!debug_info.is(a0));
+  __ lw(debug_info, FieldMemOperand(a0, SharedFunctionInfo::kDebugInfoOffset));
+  __ Branch(&load_debug_bytecode_array, ne, debug_info,
+            Operand(DebugInfo::uninitialized()));
   __ lw(kInterpreterBytecodeArrayRegister,
         FieldMemOperand(a0, SharedFunctionInfo::kFunctionDataOffset));
+  __ bind(&bytecode_array_loaded);
 
   if (FLAG_debug_code) {
     // Check function data field is actually a BytecodeArray object.
@@ -926,6 +933,12 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
 
   // Even though the first bytecode handler was called, we will never return.
   __ Abort(kUnexpectedReturnFromBytecodeHandler);
+
+  // Load debug copy of the bytecode array.
+  __ bind(&load_debug_bytecode_array);
+  __ lw(kInterpreterBytecodeArrayRegister,
+        FieldMemOperand(debug_info, DebugInfo::kAbstractCodeIndex));
+  __ Branch(&bytecode_array_loaded);
 }