Clarify the order of frame summaries and rename getters

src/debug/debug.cc

 // Copyright 2012 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/debug/debug.h"
 
 #include <memory>
 
 #include "src/api.h"
 #include "src/arguments.h"
@@ skipping 41 matching lines @@
       in_debug_event_listener_(false),
       break_on_exception_(false),
       break_on_uncaught_exception_(false),
       side_effect_check_failed_(false),
       debug_info_list_(NULL),
       feature_tracker_(isolate),
       isolate_(isolate) {
   ThreadInit();
 }
 
-BreakLocation BreakLocation::FromFrame(StandardFrame* frame) {
-  // TODO(clemensh): Handle Wasm frames.
-  DCHECK(!frame->is_wasm());
-
-  auto summary = FrameSummary::GetFirst(frame).AsJavaScript();
+BreakLocation BreakLocation::FromFrame(Handle<DebugInfo> debug_info,
+                                       JavaScriptFrame* frame) {
+  auto summary = FrameSummary::GetTop(frame).AsJavaScript();
   int offset = summary.code_offset();
   Handle<AbstractCode> abstract_code = summary.abstract_code();
   if (abstract_code->IsCode()) offset = offset - 1;
-  Handle<DebugInfo> debug_info(summary.function()->shared()->GetDebugInfo());
   auto it = BreakIterator::GetIterator(debug_info, abstract_code);
   it->SkipTo(BreakIndexFromCodeOffset(debug_info, abstract_code, offset));
   return it->GetBreakLocation();
 }
 
 void BreakLocation::AllAtCurrentStatement(Handle<DebugInfo> debug_info,
                                           JavaScriptFrame* frame,
                                           List<BreakLocation>* result_out) {
-  auto summary = FrameSummary::GetFirst(frame).AsJavaScript();
+  auto summary = FrameSummary::GetTop(frame).AsJavaScript();
   int offset = summary.code_offset();
   Handle<AbstractCode> abstract_code = summary.abstract_code();
   if (abstract_code->IsCode()) offset = offset - 1;
   int statement_position;
   {
     auto it = BreakIterator::GetIterator(debug_info, abstract_code);
     it->SkipTo(BreakIndexFromCodeOffset(debug_info, abstract_code, offset));
     statement_position = it->statement_position();
   }
   for (auto it = BreakIterator::GetIterator(debug_info, abstract_code);
@@ skipping 424 matching lines @@
   DebugScope debug_scope(this);
   if (debug_scope.failed()) return;
 
   // Postpone interrupt during breakpoint processing.
   PostponeInterruptsScope postpone(isolate_);
 
   // Return if we fail to retrieve debug info.
   Handle<JSFunction> function(frame->function());
   Handle<SharedFunctionInfo> shared(function->shared());
   if (!EnsureDebugInfo(shared, function)) return;
+  Handle<DebugInfo> debug_info(shared->GetDebugInfo(), isolate_);
 
-  BreakLocation location = BreakLocation::FromFrame(frame);
+  // Find the break location where execution has stopped.
+  BreakLocation location = BreakLocation::FromFrame(debug_info, frame);
 
   // Find actual break points, if any, and trigger debug break event.
-  MaybeHandle<FixedArray> break_points_hit;
-  if (break_points_active()) {
-    // Get the debug info, which must exist if we reach here.
-    Handle<DebugInfo> debug_info(shared->GetDebugInfo(), isolate_);
-
-    break_points_hit = CheckBreakPoints(debug_info, &location);
-  }
-
+  MaybeHandle<FixedArray> break_points_hit =
+      CheckBreakPoints(debug_info, &location);
   if (!break_points_hit.is_null()) {
     // Clear all current stepping setup.
     ClearStepping();
     // Notify the debug event listeners.
     Handle<JSArray> jsarr = isolate_->factory()->NewJSArrayWithElements(
         break_points_hit.ToHandleChecked());
     OnDebugBreak(jsarr, false);
     return;
   }
 
@@ skipping 12 matching lines @@
       if (current_fp < target_fp) return;
       step_break = true;
       break;
     case StepNext:
       // Step next should not break in a deeper frame.
       if (current_fp < target_fp) return;
       // For step-next, a tail call is like a return and should break.
       step_break = location.IsTailCall();
     // Fall through.
     case StepIn: {
-      FrameSummary summary = FrameSummary::GetFirst(frame);
+      FrameSummary summary = FrameSummary::GetTop(frame);
       step_break = step_break || location.IsReturn() || current_fp != last_fp ||
                    thread_local_.last_statement_position_ !=
                        summary.SourceStatementPosition();
       break;
     }
     case StepFrame:
       step_break = current_fp != last_fp;
       break;
   }
 
@@ skipping 428 matching lines @@
     // Step out: Find the calling JavaScript frame and flood it with
     // breakpoints.
     frames_it.Advance();
     // Fill the function to return to with one-shot break points.
     JSFunction* function = frames_it.frame()->function();
     FloodWithOneShot(Handle<JSFunction>(function));
     return;
   }
 
   // Get the debug info (create it if it does not exist).
-  auto summary = FrameSummary::GetFirst(frame).AsJavaScript();
+  auto summary = FrameSummary::GetTop(frame).AsJavaScript();
   Handle<JSFunction> function(summary.function());
   Handle<SharedFunctionInfo> shared(function->shared());
   if (!EnsureDebugInfo(shared, function)) {
     // Return if ensuring debug info failed.
     return;
   }
 
-  BreakLocation location = BreakLocation::FromFrame(frame);
+  Handle<DebugInfo> debug_info(shared->GetDebugInfo());
+  BreakLocation location = BreakLocation::FromFrame(debug_info, frame);
 
   // Any step at a return is a step-out.
   if (location.IsReturn()) step_action = StepOut;
   // A step-next at a tail call is a step-out.
   if (location.IsTailCall() && step_action == StepNext) step_action = StepOut;
 
   thread_local_.last_statement_position_ =
       summary.abstract_code()->SourceStatementPosition(summary.code_offset());
   thread_local_.last_fp_ = frame->UnpaddedFP();
   // No longer perform the current async step.
@@ skipping 546 matching lines @@
   after_break_target_ = NULL;
   if (!LiveEdit::SetAfterBreakTarget(this)) {
     // Continue just after the slot.
     after_break_target_ = frame->pc();
   }
 }
 
 bool Debug::IsBreakAtReturn(JavaScriptFrame* frame) {
   HandleScope scope(isolate_);
 
+  // Get the executing function in which the debug break occurred.
+  Handle<SharedFunctionInfo> shared(frame->function()->shared());
+
   // With no debug info there are no break points, so we can't be at a return.
-  if (!frame->function()->shared()->HasDebugInfo()) return false;
+  if (!shared->HasDebugInfo()) return false;
 
   DCHECK(!frame->is_optimized());
-  BreakLocation location = BreakLocation::FromFrame(frame);
+  Handle<DebugInfo> debug_info(shared->GetDebugInfo());
+  BreakLocation location = BreakLocation::FromFrame(debug_info, frame);
   return location.IsReturn() || location.IsTailCall();
 }
 
 void Debug::FramesHaveBeenDropped(StackFrame::Id new_break_frame_id,
                                   LiveEditFrameDropMode mode) {
   if (mode != LIVE_EDIT_CURRENTLY_SET_MODE) {
     thread_local_.frame_drop_mode_ = mode;
   }
   thread_local_.break_frame_id_ = new_break_frame_id;
 }
@@ skipping 673 matching lines @@
   OnDebugBreak(isolate_->factory()->undefined_value(), debug_command_only);
 }
 
 #ifdef DEBUG
 void Debug::PrintBreakLocation() {
   if (!FLAG_print_break_location) return;
   HandleScope scope(isolate_);
   JavaScriptFrameIterator iterator(isolate_);
   if (iterator.done()) return;
   JavaScriptFrame* frame = iterator.frame();
-  FrameSummary summary = FrameSummary::GetFirst(frame);
+  FrameSummary summary = FrameSummary::GetTop(frame);
   int source_position = summary.SourcePosition();
   Handle<Object> script_obj = summary.script();
   PrintF("[debug] break in function '");
   summary.FunctionName()->PrintOn(stdout);
   PrintF("'.\n");
   if (script_obj->IsScript()) {
     Handle<Script> script = Handle<Script>::cast(script_obj);
     Handle<String> source(String::cast(script->source()));
     Script::InitLineEnds(script);
     int line =
@@ skipping 344 matching lines @@
   logger_->DebugEvent("Put", message.text());
 }
 
 void LockingCommandMessageQueue::Clear() {
   base::LockGuard<base::Mutex> lock_guard(&mutex_);
   queue_.Clear();
 }
 
 }  // namespace internal
 }  // namespace v8