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-rw-r--r--js/src/frontend/ExpressionStatementEmitter.cpp54
1 files changed, 54 insertions, 0 deletions
diff --git a/js/src/frontend/ExpressionStatementEmitter.cpp b/js/src/frontend/ExpressionStatementEmitter.cpp
new file mode 100644
index 0000000000..bb00c831b1
--- /dev/null
+++ b/js/src/frontend/ExpressionStatementEmitter.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/ExpressionStatementEmitter.h"
+
+#include "frontend/BytecodeEmitter.h"
+#include "vm/Opcodes.h"
+
+using namespace js;
+using namespace js::frontend;
+
+using mozilla::Maybe;
+
+ExpressionStatementEmitter::ExpressionStatementEmitter(BytecodeEmitter* bce,
+ ValueUsage valueUsage)
+ : bce_(bce), valueUsage_(valueUsage) {}
+
+bool ExpressionStatementEmitter::prepareForExpr(uint32_t beginPos) {
+ MOZ_ASSERT(state_ == State::Start);
+
+ if (!bce_->updateSourceCoordNotes(beginPos)) {
+ return false;
+ }
+
+#ifdef DEBUG
+ depth_ = bce_->bytecodeSection().stackDepth();
+ state_ = State::Expr;
+#endif
+ return true;
+}
+
+bool ExpressionStatementEmitter::emitEnd() {
+ MOZ_ASSERT(state_ == State::Expr);
+ MOZ_ASSERT(bce_->bytecodeSection().stackDepth() == depth_ + 1);
+
+ // [stack] VAL
+
+ JSOp op = valueUsage_ == ValueUsage::WantValue ? JSOp::SetRval : JSOp::Pop;
+ if (!bce_->emit1(op)) {
+ // [stack] # if WantValue
+ // [stack] VAL
+ // [stack] # otherwise
+ // [stack]
+ return false;
+ }
+
+#ifdef DEBUG
+ state_ = State::End;
+#endif
+ return true;
+}