[debug] remove obsolete handling for suspended generator objects.

R=mstarzinger@chromium.org, neis@chromium.org

BUG=v8:5657

Review-Url: https://codereview.chromium.org/2526763002
Cr-Commit-Position: refs/heads/master@{#41225}

src/debug/debug.cc

@@ -1176,20 +1176,6 @@ static Address ComputeNewPcForRedirect(Code* new_code, Code* old_code,
 }
 
 
-// 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)
@@ -1253,7 +1239,6 @@ bool Debug::PrepareFunctionForBreakPoints(Handle<SharedFunctionInfo> shared) {
   }
 
   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
@@ -1278,10 +1263,6 @@ bool Debug::PrepareFunctionForBreakPoints(Handle<SharedFunctionInfo> shared) {
     // 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()) {
@@ -1293,25 +1274,12 @@ bool Debug::PrepareFunctionForBreakPoints(Handle<SharedFunctionInfo> shared) {
         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()) {
@@ -1323,12 +1291,6 @@ bool Debug::PrepareFunctionForBreakPoints(Handle<SharedFunctionInfo> shared) {
     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());