[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 1820 matching lines @@
       (line == 0) ? 0 : Smi::cast(line_ends_array->get(line - 1))->value() + 1;
   const int end = Smi::cast(line_ends_array->get(line))->value();
 
   Handle<String> source =
       handle(String::cast(script_handle->source()), isolate);
   Handle<String> str = isolate->factory()->NewSubString(source, start, end);
 
   return *str;
 }
 
-// Set one shot breakpoints for the callback function that is passed to a
-// 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) {
+// On function call, depending on circumstances, prepare for stepping in,
+// or perform a side effect check.
+RUNTIME_FUNCTION(Runtime_DebugOnFunctionCall) {
   HandleScope scope(isolate);
   DCHECK_EQ(1, args.length());
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, fun, 0);
-  isolate->debug()->PrepareStepIn(fun);
+  if (isolate->debug()->last_step_action() >= StepIn) {
+    isolate->debug()->PrepareStepIn(fun);
+  }
+  if (isolate->needs_side_effect_check() &&
+      !isolate->debug()->PerformSideEffectCheck(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();
 }
@@ skipping 67 matching lines @@
 }
 
 
 RUNTIME_FUNCTION(Runtime_DebugBreakInOptimizedCode) {
   UNIMPLEMENTED();
   return NULL;
 }
 
 }  // namespace internal
 }  // namespace v8