[generators] Decouple generator resume from fullcodegen.

src/full-codegen/arm64/full-codegen-arm64.cc

Index: src/full-codegen/arm64/full-codegen-arm64.cc
diff --git a/src/full-codegen/arm64/full-codegen-arm64.cc b/src/full-codegen/arm64/full-codegen-arm64.cc
index eb044dbfd9dd0a650fa31dc1fba10a8933a6dab8..fbd653e9eccb575d1a2c2241cabd923323f65dbe 100644
--- a/src/full-codegen/arm64/full-codegen-arm64.cc
+++ b/src/full-codegen/arm64/full-codegen-arm64.cc
@@ -3744,7 +3744,7 @@ void FullCodeGenerator::VisitYield(Yield* expr) {
   // and suchlike. The implementation changes a little by bleeding_edge so I
   // don't want to spend too much time on it now.
 
-  Label suspend, continuation, post_runtime, resume;
+  Label suspend, continuation, post_runtime, resume, exception;
 
   __ B(&suspend);
   // TODO(jbramley): This label is bound here because the following code
@@ -3756,12 +3756,18 @@ void FullCodeGenerator::VisitYield(Yield* expr) {
   // respective resume operation).
   __ RecordGeneratorContinuation();
   __ Pop(x1);
-  __ Cmp(x1, Smi::FromInt(JSGeneratorObject::RETURN));
-  __ B(ne, &resume);
+  STATIC_ASSERT(JSGeneratorObject::kNext < JSGeneratorObject::kReturn);
+  STATIC_ASSERT(JSGeneratorObject::kThrow > JSGeneratorObject::kReturn);
+  __ Cmp(x1, Operand(Smi::FromInt(JSGeneratorObject::kReturn)));
+  __ B(lt, &resume);
   __ Push(result_register());
+  __ B(gt, &exception);
   EmitCreateIteratorResult(true);
   EmitUnwindAndReturn();
 
+  __ Bind(&exception);
+  __ CallRuntime(Runtime::kThrow);
+
   __ Bind(&suspend);
   OperandStackDepthIncrement(1);  // Not popped on this path.
   VisitForAccumulatorValue(expr->generator_object());
@@ -3786,110 +3792,6 @@ void FullCodeGenerator::VisitYield(Yield* expr) {
   context()->Plug(result_register());
 }
 
-
-void FullCodeGenerator::EmitGeneratorResume(Expression *generator,
-    Expression *value,
-    JSGeneratorObject::ResumeMode resume_mode) {
-  ASM_LOCATION("FullCodeGenerator::EmitGeneratorResume");
-  Register generator_object = x1;
-  Register the_hole = x2;
-  Register operand_stack_size = w3;
-  Register function = x4;
-
-  // The value stays in x0, and is ultimately read by the resumed generator, as
-  // if CallRuntime(Runtime::kSuspendJSGeneratorObject) returned it. Or it
-  // is read to throw the value when the resumed generator is already closed. x1
-  // will hold the generator object until the activation has been resumed.
-  VisitForStackValue(generator);
-  VisitForAccumulatorValue(value);
-  PopOperand(generator_object);
-
-  // Store input value into generator object.
-  __ Str(result_register(),
-         FieldMemOperand(x1, JSGeneratorObject::kInputOffset));
-  __ Mov(x2, result_register());
-  __ RecordWriteField(x1, JSGeneratorObject::kInputOffset, x2, x3,
-                      kLRHasBeenSaved, kDontSaveFPRegs);
-
-  // Load suspended function and context.
-  __ Ldr(cp, FieldMemOperand(generator_object,
-                             JSGeneratorObject::kContextOffset));
-  __ Ldr(function, FieldMemOperand(generator_object,
-                                   JSGeneratorObject::kFunctionOffset));
-
-  // Load receiver and store as the first argument.
-  __ Ldr(x10, FieldMemOperand(generator_object,
-                              JSGeneratorObject::kReceiverOffset));
-  __ Push(x10);
-
-  // Push holes for arguments to generator function. Since the parser forced
-  // context allocation for any variables in generators, the actual argument
-  // values have already been copied into the context and these dummy values
-  // will never be used.
-  __ Ldr(x10, FieldMemOperand(function, JSFunction::kSharedFunctionInfoOffset));
-
-  // The number of arguments is stored as an int32_t, and -1 is a marker
-  // (SharedFunctionInfo::kDontAdaptArgumentsSentinel), so we need sign
-  // extension to correctly handle it. However, in this case, we operate on
-  // 32-bit W registers, so extension isn't required.
-  __ Ldr(w10, FieldMemOperand(x10,
-                              SharedFunctionInfo::kFormalParameterCountOffset));
-  __ LoadRoot(the_hole, Heap::kTheHoleValueRootIndex);
-  __ PushMultipleTimes(the_hole, w10);
-
-  // Enter a new JavaScript frame, and initialize its slots as they were when
-  // the generator was suspended.
-  Label resume_frame, done;
-  __ Bl(&resume_frame);
-  __ B(&done);
-
-  __ Bind(&resume_frame);
-  __ Push(lr,           // Return address.
-          fp,           // Caller's frame pointer.
-          cp,           // Callee's context.
-          function);    // Callee's JS Function.
-  __ Add(fp, __ StackPointer(), kPointerSize * 2);
-
-  // Load and untag the operand stack size.
-  __ Ldr(x10, FieldMemOperand(generator_object,
-                              JSGeneratorObject::kOperandStackOffset));
-  __ Ldr(operand_stack_size,
-         UntagSmiFieldMemOperand(x10, FixedArray::kLengthOffset));
-
-  // If we are sending a value and there is no operand stack, we can jump back
-  // in directly.
-  if (resume_mode == JSGeneratorObject::NEXT) {
-    Label slow_resume;
-    __ Cbnz(operand_stack_size, &slow_resume);
-    __ Ldr(x10, FieldMemOperand(function, JSFunction::kCodeEntryOffset));
-    __ Ldrsw(x11,
-             UntagSmiFieldMemOperand(generator_object,
-                                     JSGeneratorObject::kContinuationOffset));
-    __ Add(x10, x10, x11);
-    __ Mov(x12, Smi::FromInt(JSGeneratorObject::kGeneratorExecuting));
-    __ Str(x12, FieldMemOperand(generator_object,
-                                JSGeneratorObject::kContinuationOffset));
-    __ Push(Smi::FromInt(resume_mode));  // Consumed in continuation.
-    __ Br(x10);
-
-    __ Bind(&slow_resume);
-  }
-
-  // Otherwise, we push holes for the operand stack and call the runtime to fix
-  // up the stack and the handlers.
-  __ PushMultipleTimes(the_hole, operand_stack_size);
-
-  __ Mov(x10, Smi::FromInt(resume_mode));
-  __ Push(Smi::FromInt(resume_mode));  // Consumed in continuation.
-  __ Push(generator_object, result_register(), x10);
-  __ CallRuntime(Runtime::kResumeJSGeneratorObject);
-  // Not reached: the runtime call returns elsewhere.
-  __ Unreachable();
-
-  __ Bind(&done);
-  context()->Plug(result_register());
-}
-
 void FullCodeGenerator::PushOperands(Register reg1, Register reg2) {
   OperandStackDepthIncrement(2);
   __ Push(reg1, reg2);