[generators] Decouple generator resume from fullcodegen.

src/runtime/runtime-generator.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/factory.h"
 #include "src/frames-inl.h"
 #include "src/objects-inl.h"
@@ skipping 54 matching lines @@
   } else {
     Handle<FixedArray> operand_stack =
         isolate->factory()->NewFixedArray(operands_count);
     frame->SaveOperandStack(*operand_stack);
     generator_object->set_operand_stack(*operand_stack);
   }
 
   return isolate->heap()->undefined_value();
 }
 
-
-// Note that this function is the slow path for resuming generators.  It is only
-// called if the suspended activation had operands on the stack, stack handlers
-// needing rewinding, or if the resume should throw an exception.  The fast path
-// is handled directly in FullCodeGenerator::EmitGeneratorResume(), which is
-// inlined into GeneratorNext, GeneratorReturn, and GeneratorThrow.
-// EmitGeneratorResume is called in any case, as it needs to reconstruct the
-// stack frame and make space for arguments and operands.
-RUNTIME_FUNCTION(Runtime_ResumeJSGeneratorObject) {
-  SealHandleScope shs(isolate);
-  DCHECK(args.length() == 3);
-  CONVERT_ARG_CHECKED(JSGeneratorObject, generator_object, 0);
-  CONVERT_ARG_CHECKED(Object, value, 1);
-  CONVERT_SMI_ARG_CHECKED(resume_mode_int, 2);
-  JavaScriptFrameIterator stack_iterator(isolate);
-  JavaScriptFrame* frame = stack_iterator.frame();
-
-  DCHECK_EQ(frame->function(), generator_object->function());
-  DCHECK(frame->function()->shared()->is_compiled());
-  DCHECK(!frame->function()->IsOptimized());
-
-  STATIC_ASSERT(JSGeneratorObject::kGeneratorExecuting < 0);
-  STATIC_ASSERT(JSGeneratorObject::kGeneratorClosed == 0);
-
-  Code* code = generator_object->function()->shared()->code();
-  int offset = generator_object->continuation();
-  DCHECK_GT(offset, 0);
-  frame->set_pc(code->instruction_start() + offset);
-  if (FLAG_enable_embedded_constant_pool) {
-    frame->set_constant_pool(code->constant_pool());
-  }
-  generator_object->set_continuation(JSGeneratorObject::kGeneratorExecuting);
-
-  FixedArray* operand_stack = generator_object->operand_stack();
-  int operands_count = operand_stack->length();
-  if (operands_count != 0) {
-    frame->RestoreOperandStack(operand_stack);
-    generator_object->set_operand_stack(isolate->heap()->empty_fixed_array());
-  }
-
-  JSGeneratorObject::ResumeMode resume_mode =
-      static_cast<JSGeneratorObject::ResumeMode>(resume_mode_int);
-  switch (resume_mode) {
-    // Note: this looks like NEXT and RETURN are the same but RETURN receives
-    // special treatment in the generator code (to which we return here).
-    case JSGeneratorObject::NEXT:
-    case JSGeneratorObject::RETURN:
-      return value;
-    case JSGeneratorObject::THROW:
-      return isolate->Throw(value);
-  }
-
-  UNREACHABLE();
-  return isolate->ThrowIllegalOperation();
-}
-
-
 RUNTIME_FUNCTION(Runtime_GeneratorClose) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0);
 
   generator->set_continuation(JSGeneratorObject::kGeneratorClosed);
 
   return isolate->heap()->undefined_value();
 }
 
@@ skipping 46 matching lines @@
   if (generator->is_suspended()) {
     Handle<Code> code(generator->function()->code(), isolate);
     int offset = generator->continuation();
     RUNTIME_ASSERT(0 <= offset && offset < code->instruction_size());
     return Smi::FromInt(code->SourcePosition(offset));
   }
 
   return isolate->heap()->undefined_value();
 }
 
-// Optimization for builtins calling any of the following three functions is
-// disabled in js/generator.js and compiler.cc, hence they are unreachable.
-
-RUNTIME_FUNCTION(Runtime_GeneratorNext) {
-  UNREACHABLE();
-  return nullptr;
-}
-
-RUNTIME_FUNCTION(Runtime_GeneratorReturn) {
-  UNREACHABLE();
-  return nullptr;
-}
-
-RUNTIME_FUNCTION(Runtime_GeneratorThrow) {
-  UNREACHABLE();
-  return nullptr;
-}
-
 }  // namespace internal
 }  // namespace v8