[generators] Implement Generator.prototype.return.

src/full-codegen/ia32/full-codegen-ia32.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.
 
 #if V8_TARGET_ARCH_IA32
 
 #include "src/ast/scopes.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 1828 matching lines @@
     case Yield::kSuspend:
       // Pop value from top-of-stack slot; box result into result register.
       EmitCreateIteratorResult(false);
       __ push(result_register());
       // Fall through.
     case Yield::kInitial: {
       Label suspend, continuation, post_runtime, resume;
 
       __ jmp(&suspend);
       __ bind(&continuation);
+      // When we arrive here, the stack top is the resume mode and
+      // result_register() holds the input value (the argument given to the
+      // respective resume operation).
       __ RecordGeneratorContinuation();
-      __ jmp(&resume);
+      __ pop(ebx);
+      __ cmp(ebx, Immediate(Smi::FromInt(JSGeneratorObject::RETURN)));
+      __ j(not_equal, &resume);
+      __ push(result_register());
+      EmitCreateIteratorResult(true);
+      EmitUnwindBeforeReturn();
+      EmitReturnSequence();
 
       __ bind(&suspend);
       VisitForAccumulatorValue(expr->generator_object());
       DCHECK(continuation.pos() > 0 && Smi::IsValid(continuation.pos()));
       __ mov(FieldOperand(eax, JSGeneratorObject::kContinuationOffset),
              Immediate(Smi::FromInt(continuation.pos())));
       __ mov(FieldOperand(eax, JSGeneratorObject::kContextOffset), esi);
       __ mov(ecx, esi);
       __ RecordWriteField(eax, JSGeneratorObject::kContextOffset, ecx, edx,
                           kDontSaveFPRegs);
@@ skipping 192 matching lines @@
   if (resume_mode == JSGeneratorObject::NEXT) {
     Label slow_resume;
     __ cmp(edx, Immediate(0));
     __ j(not_zero, &slow_resume);
     __ mov(edx, FieldOperand(edi, JSFunction::kCodeEntryOffset));
     __ mov(ecx, FieldOperand(ebx, JSGeneratorObject::kContinuationOffset));
     __ SmiUntag(ecx);
     __ add(edx, ecx);
     __ mov(FieldOperand(ebx, JSGeneratorObject::kContinuationOffset),
            Immediate(Smi::FromInt(JSGeneratorObject::kGeneratorExecuting)));
+    __ Push(Smi::FromInt(resume_mode));  // Consumed in continuation.
     __ jmp(edx);
     __ bind(&slow_resume);
   }
 
   // Otherwise, we push holes for the operand stack and call the runtime to fix
   // up the stack and the handlers.
   Label push_operand_holes, call_resume;
   __ bind(&push_operand_holes);
   __ sub(edx, Immediate(1));
   __ j(carry, &call_resume);
   __ push(ecx);
   __ jmp(&push_operand_holes);
   __ bind(&call_resume);
+  __ Push(Smi::FromInt(resume_mode));  // Consumed in continuation.
   __ push(ebx);
   __ push(result_register());
   __ Push(Smi::FromInt(resume_mode));
   __ CallRuntime(Runtime::kResumeJSGeneratorObject);
   // Not reached: the runtime call returns elsewhere.
   __ Abort(kGeneratorFailedToResume);
 
   __ bind(&done);
   context()->Plug(result_register());
 }
@@ skipping 2621 matching lines @@
             Assembler::target_address_at(call_target_address,
                                          unoptimized_code));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_IA32