1 files changed, 182 insertions, 0 deletions
diff --git a/js/src/frontend/NameOpEmitter.h b/js/src/frontend/NameOpEmitter.h
new file mode 100644
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+++ b/js/src/frontend/NameOpEmitter.h
@@ -0,0 +1,182 @@
+/* -*- 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/. */
+
+#ifndef frontend_NameOpEmitter_h
+#define frontend_NameOpEmitter_h
+
+#include "mozilla/Attributes.h"
+
+#include "frontend/NameAnalysisTypes.h"
+#include "frontend/ParserAtom.h"  // TaggedParserAtomIndex
+#include "vm/SharedStencil.h"     // GCThingIndex
+
+namespace js {
+namespace frontend {
+
+struct BytecodeEmitter;
+enum class ValueUsage;
+
+// Class for emitting bytecode for name operation.
+//
+// Usage: (check for the return value is omitted for simplicity)
+//
+//   `name;`
+//     NameOpEmitter noe(this, atom_of_name
+//                       NameOpEmitter::Kind::Get);
+//     noe.emitGet();
+//
+//   `name();`
+//     this is handled in CallOrNewEmitter
+//
+//   `name++;`
+//     NameOpEmitter noe(this, atom_of_name
+//                       NameOpEmitter::Kind::PostIncrement);
+//     noe.emitIncDec();
+//
+//   `name = 10;`
+//     NameOpEmitter noe(this, atom_of_name
+//                       NameOpEmitter::Kind::SimpleAssignment);
+//     noe.prepareForRhs();
+//     emit(10);
+//     noe.emitAssignment();
+//
+//   `name += 10;`
+//     NameOpEmitter noe(this, atom_of_name
+//                       NameOpEmitter::Kind::CompoundAssignment);
+//     noe.prepareForRhs();
+//     emit(10);
+//     emit_add_op_here();
+//     noe.emitAssignment();
+//
+//   `name = 10;` part of `let name = 10;`
+//     NameOpEmitter noe(this, atom_of_name
+//                       NameOpEmitter::Kind::Initialize);
+//     noe.prepareForRhs();
+//     emit(10);
+//     noe.emitAssignment();
+//
+class MOZ_STACK_CLASS NameOpEmitter {
+ public:
+  enum class Kind {
+    Get,
+    Call,
+    PostIncrement,
+    PreIncrement,
+    PostDecrement,
+    PreDecrement,
+    SimpleAssignment,
+    CompoundAssignment,
+    Initialize
+  };
+
+ private:
+  BytecodeEmitter* bce_;
+
+  Kind kind_;
+
+  bool emittedBindOp_ = false;
+
+  TaggedParserAtomIndex name_;
+
+  GCThingIndex atomIndex_;
+
+  NameLocation loc_;
+
+#ifdef DEBUG
+  // The state of this emitter.
+  //
+  //               [Get]
+  //               [Call]
+  // +-------+      emitGet +-----+
+  // | Start |-+-+--------->| Get |
+  // +-------+   |          +-----+
+  //             |
+  //             | [PostIncrement]
+  //             | [PreIncrement]
+  //             | [PostDecrement]
+  //             | [PreDecrement]
+  //             |   emitIncDec +--------+
+  //             +------------->| IncDec |
+  //             |              +--------+
+  //             |
+  //             | [SimpleAssignment]
+  //             |                        prepareForRhs +-----+
+  //             +--------------------->+-------------->| Rhs |-+
+  //             |                      ^               +-----+ |
+  //             |                      |                       |
+  //             |                      |    +------------------+
+  //             | [CompoundAssignment] |    |
+  //             |   emitGet +-----+    |    | emitAssignment +------------+
+  //             +---------->| Get |----+    + -------------->| Assignment |
+  //                         +-----+                          +------------+
+  enum class State {
+    // The initial state.
+    Start,
+
+    // After calling emitGet.
+    Get,
+
+    // After calling emitIncDec.
+    IncDec,
+
+    // After calling prepareForRhs.
+    Rhs,
+
+    // After calling emitAssignment.
+    Assignment,
+  };
+  State state_ = State::Start;
+#endif
+
+ public:
+  NameOpEmitter(BytecodeEmitter* bce, TaggedParserAtomIndex name, Kind kind);
+  NameOpEmitter(BytecodeEmitter* bce, TaggedParserAtomIndex name,
+                const NameLocation& loc, Kind kind);
+
+ private:
+  [[nodiscard]] bool isCall() const { return kind_ == Kind::Call; }
+
+  [[nodiscard]] bool isSimpleAssignment() const {
+    return kind_ == Kind::SimpleAssignment;
+  }
+
+  [[nodiscard]] bool isCompoundAssignment() const {
+    return kind_ == Kind::CompoundAssignment;
+  }
+
+  [[nodiscard]] bool isIncDec() const {
+    return isPostIncDec() || isPreIncDec();
+  }
+
+  [[nodiscard]] bool isPostIncDec() const {
+    return kind_ == Kind::PostIncrement || kind_ == Kind::PostDecrement;
+  }
+
+  [[nodiscard]] bool isPreIncDec() const {
+    return kind_ == Kind::PreIncrement || kind_ == Kind::PreDecrement;
+  }
+
+  [[nodiscard]] bool isInc() const {
+    return kind_ == Kind::PostIncrement || kind_ == Kind::PreIncrement;
+  }
+
+  [[nodiscard]] bool isInitialize() const { return kind_ == Kind::Initialize; }
+
+ public:
+  [[nodiscard]] bool emittedBindOp() const { return emittedBindOp_; }
+
+  [[nodiscard]] const NameLocation& loc() const { return loc_; }
+
+  [[nodiscard]] bool emitGet();
+  [[nodiscard]] bool prepareForRhs();
+  [[nodiscard]] bool emitAssignment();
+  [[nodiscard]] bool emitIncDec(ValueUsage valueUsage);
+};
+
+} /* namespace frontend */
+} /* namespace js */
+
+#endif /* frontend_NameOpEmitter_h */