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-rw-r--r--js/src/frontend/DefaultEmitter.cpp75
1 files changed, 75 insertions, 0 deletions
diff --git a/js/src/frontend/DefaultEmitter.cpp b/js/src/frontend/DefaultEmitter.cpp
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+++ b/js/src/frontend/DefaultEmitter.cpp
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "frontend/DefaultEmitter.h"
+
+#include "mozilla/Assertions.h" // MOZ_ASSERT
+
+#include "frontend/BytecodeEmitter.h" // BytecodeEmitter
+#include "vm/Opcodes.h" // JSOp
+
+using namespace js;
+using namespace js::frontend;
+
+using mozilla::Nothing;
+
+DefaultEmitter::DefaultEmitter(BytecodeEmitter* bce) : bce_(bce) {}
+
+bool DefaultEmitter::prepareForDefault() {
+ MOZ_ASSERT(state_ == State::Start);
+
+ // [stack] VALUE
+
+ ifUndefined_.emplace(bce_);
+ if (!ifUndefined_->emitIf(Nothing())) {
+ return false;
+ }
+
+ if (!bce_->emit1(JSOp::Dup)) {
+ // [stack] VALUE VALUE
+ return false;
+ }
+ if (!bce_->emit1(JSOp::Undefined)) {
+ // [stack] VALUE VALUE UNDEFINED
+ return false;
+ }
+ if (!bce_->emit1(JSOp::StrictEq)) {
+ // [stack] VALUE EQ?
+ return false;
+ }
+
+ if (!ifUndefined_->emitThen()) {
+ // [stack] VALUE
+ return false;
+ }
+
+ if (!bce_->emit1(JSOp::Pop)) {
+ // [stack]
+ return false;
+ }
+
+#ifdef DEBUG
+ state_ = State::Default;
+#endif
+ return true;
+}
+
+bool DefaultEmitter::emitEnd() {
+ MOZ_ASSERT(state_ == State::Default);
+
+ // [stack] DEFAULTVALUE
+
+ if (!ifUndefined_->emitEnd()) {
+ // [stack] VALUE/DEFAULTVALUE
+ return false;
+ }
+ ifUndefined_.reset();
+
+#ifdef DEBUG
+ state_ = State::End;
+#endif
+ return true;
+}