[debug] remove obsolete handling for suspended generator objects.

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 1158 matching lines @@
     Code* current = Code::GetCodeFromTargetAddress(rinfo->target_address());
     if (MatchingCodeTargets(target, current)) index--;
     if (index == 0) return rinfo->pc() + delta;
   }
 
   UNREACHABLE();
   return NULL;
 }
 
 
-// Count the number of continuations at which the current pc offset is at.
-static int ComputeContinuationIndexFromPcOffset(Code* code, int pc_offset) {
-  UNREACHABLE();
-  return 666;
-}
-
-
-// Find the pc offset for the given continuation index.
-static int ComputePcOffsetFromContinuationIndex(Code* code, int index) {
-  UNREACHABLE();
-  return 666;
-}
-
-
 class RedirectActiveFunctions : public ThreadVisitor {
  public:
   explicit RedirectActiveFunctions(SharedFunctionInfo* shared)
       : shared_(shared) {
     DCHECK(shared->HasDebugCode());
   }
 
   void VisitThread(Isolate* isolate, ThreadLocalTop* top) {
     for (JavaScriptFrameIterator it(isolate, top); !it.done(); it.Advance()) {
       JavaScriptFrame* frame = it.frame();
@@ skipping 43 matching lines @@
 
 
 bool Debug::PrepareFunctionForBreakPoints(Handle<SharedFunctionInfo> shared) {
   DCHECK(shared->is_compiled());
 
   if (isolate_->concurrent_recompilation_enabled()) {
     isolate_->optimizing_compile_dispatcher()->Flush();
   }
 
   List<Handle<JSFunction> > functions;
-  List<Handle<JSGeneratorObject> > suspended_generators;
 
   // Flush all optimized code maps. Note that the below heap iteration does not
   // cover this, because the given function might have been inlined into code
   // for which no JSFunction exists.
   {
     SharedFunctionInfo::Iterator iterator(isolate_);
     while (SharedFunctionInfo* shared = iterator.Next()) {
       shared->ClearCodeFromOptimizedCodeMap();
     }
   }
 
   // Make sure we abort incremental marking.
   isolate_->heap()->CollectAllGarbage(Heap::kMakeHeapIterableMask,
                                       GarbageCollectionReason::kDebugger);
 
   DCHECK(shared->is_compiled());
   bool baseline_exists = shared->HasBaselineCode();
 
   {
     // TODO(yangguo): with bytecode, we still walk the heap to find all
     // optimized code for the function to deoptimize. We can probably be
     // smarter here and avoid the heap walk.
     HeapIterator iterator(isolate_->heap());
     HeapObject* obj;
-    // Continuation from old-style generators need to be recomputed.
-    // TODO(yangguo): Remove code for old-style generators.
-    bool find_resumables =
-        baseline_exists && IsResumableFunction(shared->kind());
 
     while ((obj = iterator.next())) {
       if (obj->IsJSFunction()) {
         JSFunction* function = JSFunction::cast(obj);
         if (!function->Inlines(*shared)) continue;
         if (function->code()->kind() == Code::OPTIMIZED_FUNCTION) {
           Deoptimizer::DeoptimizeFunction(function);
         }
         if (baseline_exists && function->shared() == *shared) {
           functions.Add(handle(function));
         }
-      } else if (find_resumables && obj->IsJSGeneratorObject()) {
-        // This case handles async functions as well, as they use generator
-        // objects for in-progress async function execution.
-        JSGeneratorObject* generator_obj = JSGeneratorObject::cast(obj);
-        if (!generator_obj->is_suspended()) continue;
-        JSFunction* function = generator_obj->function();
-        if (!function->Inlines(*shared)) continue;
-        int pc_offset = generator_obj->continuation();
-        int index =
-            ComputeContinuationIndexFromPcOffset(function->code(), pc_offset);
-        generator_obj->set_continuation(index);
-        suspended_generators.Add(handle(generator_obj));
       }
     }
   }
 
   // We do not need to replace code to debug bytecode.
   DCHECK(baseline_exists || functions.is_empty());
-  DCHECK(baseline_exists || suspended_generators.is_empty());
 
   // We do not need to recompile to debug bytecode.
   if (baseline_exists && !shared->code()->has_debug_break_slots()) {
     if (!Compiler::CompileDebugCode(shared)) return false;
   }
 
   for (Handle<JSFunction> const function : functions) {
     function->ReplaceCode(shared->code());
     JSFunction::EnsureLiterals(function);
   }
 
-  for (Handle<JSGeneratorObject> const generator_obj : suspended_generators) {
-    int index = generator_obj->continuation();
-    int pc_offset = ComputePcOffsetFromContinuationIndex(shared->code(), index);
-    generator_obj->set_continuation(pc_offset);
-  }
-
   // Update PCs on the stack to point to recompiled code.
   RedirectActiveFunctions redirect_visitor(*shared);
   redirect_visitor.VisitThread(isolate_, isolate_->thread_local_top());
   isolate_->thread_manager()->IterateArchivedThreads(&redirect_visitor);
 
   return true;
 }
 
 namespace {
 template <typename Iterator>
@@ skipping 1269 matching lines @@
 }
 
 
 void LockingCommandMessageQueue::Clear() {
   base::LockGuard<base::Mutex> lock_guard(&mutex_);
   queue_.Clear();
 }
 
 }  // namespace internal
 }  // namespace v8