Revert "[debug] add runtime side effect check for StaCurrentContextSlot"

This reverts commit 0340874b.

Reason for revert: Tentative revert for https://crbug.com/v8/7626

Original change's description:
> [debug] add runtime side effect check for StaCurrentContextSlot
> 
> R=​yangguo@chromium.org
> 
> Bug: v8:7588
> Change-Id: If78f6dd460c7423923800a98d44520c1bf71663c
> Reviewed-on: https://chromium-review.googlesource.com/996236
> Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#52398}

TBR=yangguo@chromium.org,kozyatinskiy@chromium.org

Change-Id: I77a679649a6149607aefd44f6b7f3f6dfe548776
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7588
Reviewed-on: https://chromium-review.googlesource.com/998036Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52428}

src/debug/debug-evaluate.cc

@@ -858,7 +858,6 @@ bool BytecodeRequiresRuntimeCheck(interpreter::Bytecode bytecode) {
     case Bytecode::kStaKeyedProperty:
     case Bytecode::kStaInArrayLiteral:
     case Bytecode::kStaDataPropertyInLiteral:
-    case Bytecode::kStaCurrentContextSlot:
       return true;
     default:
       return false;

src/debug/debug.cc

@@ -2413,28 +2413,8 @@ bool Debug::PerformSideEffectCheckForCallback(Handle<Object> callback_info) {
   return false;
 }
 
-bool Debug::PerformSideEffectCheckAtBytecode(InterpretedFrame* frame) {
-  using interpreter::Bytecode;
-
+bool Debug::PerformSideEffectCheckForObject(Handle<Object> object) {
   DCHECK_EQ(isolate_->debug_execution_mode(), DebugInfo::kSideEffects);
-  SharedFunctionInfo* shared = frame->function()->shared();
-  BytecodeArray* bytecode_array = shared->bytecode_array();
-  int offset = frame->GetBytecodeOffset();
-  interpreter::BytecodeArrayAccessor bytecode_accessor(handle(bytecode_array),
-                                                       offset);
-
-  Bytecode bytecode = bytecode_accessor.current_bytecode();
-  interpreter::Register reg;
-  switch (bytecode) {
-    case Bytecode::kStaCurrentContextSlot:
-      reg = interpreter::Register::current_context();
-      break;
-    default:
-      reg = bytecode_accessor.GetRegisterOperand(0);
-      break;
-  }
-  Handle<Object> object =
-      handle(frame->ReadInterpreterRegister(reg.index()), isolate_);
   if (object->IsHeapObject()) {
     Address address = Handle<HeapObject>::cast(object)->address();
     if (temporary_objects_->HasObject(address)) {
@@ -2442,6 +2422,14 @@ bool Debug::PerformSideEffectCheckAtBytecode(InterpretedFrame* frame) {
     }
   }
   if (FLAG_trace_side_effect_free_debug_evaluate) {
+    JavaScriptFrameIterator it(isolate_);
+    InterpretedFrame* interpreted_frame =
+        reinterpret_cast<InterpretedFrame*>(it.frame());
+    SharedFunctionInfo* shared = interpreted_frame->function()->shared();
+    BytecodeArray* bytecode_array = shared->bytecode_array();
+    int bytecode_offset = interpreted_frame->GetBytecodeOffset();
+    interpreter::Bytecode bytecode =
+        interpreter::Bytecodes::FromByte(bytecode_array->get(bytecode_offset));
     PrintF("[debug-evaluate] %s failed runtime side effect check.\n",
            interpreter::Bytecodes::ToString(bytecode));
   }

src/debug/debug.h

@@ -347,7 +347,7 @@ class Debug {
 
   bool PerformSideEffectCheck(Handle<JSFunction> function);
   bool PerformSideEffectCheckForCallback(Handle<Object> callback_info);
-  bool PerformSideEffectCheckAtBytecode(InterpretedFrame* frame);
+  bool PerformSideEffectCheckForObject(Handle<Object> object);
 
   // Flags and states.
   DebugScope* debugger_entry() {

src/runtime/runtime-debug.cc

@@ -59,8 +59,15 @@ RUNTIME_FUNCTION_RETURN_PAIR(Runtime_DebugBreakOnBytecode) {
 
   bool side_effect_check_failed = false;
   if (isolate->debug_execution_mode() == DebugInfo::kSideEffects) {
-    side_effect_check_failed =
-        !isolate->debug()->PerformSideEffectCheckAtBytecode(interpreted_frame);
+    int offset = interpreted_frame->GetBytecodeOffset();
+    interpreter::BytecodeArrayAccessor bytecode_accessor(handle(bytecode_array),
+                                                         offset);
+    interpreter::Register reg = bytecode_accessor.GetRegisterOperand(0);
+    Handle<Object> first_operand = handle(
+        interpreted_frame->ReadInterpreterRegister(reg.index()), isolate);
+    if (!isolate->debug()->PerformSideEffectCheckForObject(first_operand)) {
+      side_effect_check_failed = true;
+    }
   }
 
   if (Bytecodes::Returns(bytecode)) {

test/debugger/debug/side-effect/debug-evaluate-no-side-effect-runtime-check.js

@@ -4,13 +4,6 @@
 
 Debug = debug.Debug;
 
-// StaCurrentContextSlot
-success(10, `(function(){
-  const x = 10;
-  function f1() {return x;}
-  return x;
-})()`);
-
 // StaNamedProperty
 var a = {name: 'foo'};
 function set_name(a) {