[debugger] infrastructure for side-effect-free debug-evaluate.

src/runtime/runtime-debug.cc

 // Copyright 2014 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.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
+#include "src/compiler.h"
 #include "src/debug/debug-evaluate.h"
 #include "src/debug/debug-frames.h"
 #include "src/debug/debug-scopes.h"
 #include "src/debug/debug.h"
 #include "src/debug/liveedit.h"
 #include "src/frames-inl.h"
 #include "src/globals.h"
 #include "src/interpreter/bytecodes.h"
 #include "src/interpreter/interpreter.h"
 #include "src/isolate-inl.h"
@@ skipping 1832 matching lines @@
 // built-in function such as Array.forEach to enable stepping into the callback,
 // if we are indeed stepping and the callback is subject to debugging.
 RUNTIME_FUNCTION(Runtime_DebugPrepareStepInIfStepping) {
   HandleScope scope(isolate);
   DCHECK_EQ(1, args.length());
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, fun, 0);
   isolate->debug()->PrepareStepIn(fun);
   return isolate->heap()->undefined_value();
 }
 
+// Perform %DebugPrepareStepInIfStepping and a read-only check.
+RUNTIME_FUNCTION(Runtime_DebugOnFunctionCall) {
+  HandleScope scope(isolate);
+  DCHECK_EQ(1, args.length());
+  CONVERT_ARG_HANDLE_CHECKED(JSFunction, fun, 0);
+  if (isolate->debug()->last_step_action() >= StepIn) {

[jgruber, 2017/01/10 12:46:38]

Maybe we should refactor these '>= StepIn' checks to improve readability and
robustness (e.g. what if we add a new step action). It's also not documented in
debug.h that the order of StepActions is significant. 

[Yang, 2017/01/10 14:14:07]

We do have static asserts in many places to guard the order. I'd like to do that
clean up in a separate CL.

+    isolate->debug()->PrepareStepIn(fun);
+  }
+  if (isolate->debug()->needs_readonly_check() &&
+      !isolate->debug()->PerformReadOnlyCheck(fun)) {
+    return isolate->heap()->exception();
+  }
+  return isolate->heap()->undefined_value();
+}
+
 // Set one shot breakpoints for the suspended generator object.
 RUNTIME_FUNCTION(Runtime_DebugPrepareStepInSuspendedGenerator) {
   HandleScope scope(isolate);
   DCHECK_EQ(0, args.length());
   isolate->debug()->PrepareStepInSuspendedGenerator();
   return isolate->heap()->undefined_value();
 }
 
 RUNTIME_FUNCTION(Runtime_DebugRecordGenerator) {
   HandleScope scope(isolate);
@@ skipping 45 matching lines @@
 }
 
 
 RUNTIME_FUNCTION(Runtime_DebugBreakInOptimizedCode) {
   UNIMPLEMENTED();
   return NULL;
 }
 
 }  // namespace internal
 }  // namespace v8