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diff --git a/libelffile/dwarf/expression.h b/libelffile/dwarf/expression.h
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+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_LIBELFFILE_DWARF_EXPRESSION_H_
+#define ART_LIBELFFILE_DWARF_EXPRESSION_H_
+
+#include <cstddef>
+#include <cstdint>
+
+#include "dwarf/dwarf_constants.h"
+#include "dwarf/writer.h"
+
+namespace art {
+namespace dwarf {
+
+// Writer for DWARF expressions which are used in .debug_info and .debug_loc sections.
+// See the DWARF specification for the precise meaning of the opcodes.
+// If multiple equivalent encodings are possible, it will choose the most compact one.
+// The writer is not exhaustive - it only implements opcodes we have needed so far.
+class Expression : private Writer<> {
+ public:
+  using Writer<>::data;
+  using Writer<>::size;
+
+  // Push signed integer on the stack.
+  void WriteOpConsts(int32_t value) {
+    if (0 <= value && value < 32) {
+      PushUint8(DW_OP_lit0 + value);
+    } else {
+      PushUint8(DW_OP_consts);
+      PushSleb128(value);
+    }
+  }
+
+  // Push unsigned integer on the stack.
+  void WriteOpConstu(uint32_t value) {
+    if (value < 32) {
+      PushUint8(DW_OP_lit0 + value);
+    } else {
+      PushUint8(DW_OP_constu);
+      PushUleb128(value);
+    }
+  }
+
+  // Variable is stored in given register.
+  void WriteOpReg(uint32_t dwarf_reg_num) {
+    if (dwarf_reg_num < 32) {
+      PushUint8(DW_OP_reg0 + dwarf_reg_num);
+    } else {
+      PushUint8(DW_OP_regx);
+      PushUleb128(dwarf_reg_num);
+    }
+  }
+
+  // Variable is stored on stack.  Also see DW_AT_frame_base.
+  void WriteOpFbreg(int32_t stack_offset) {
+    PushUint8(DW_OP_fbreg);
+    PushSleb128(stack_offset);
+  }
+
+  // The variable is stored in multiple locations (pieces).
+  void WriteOpPiece(uint32_t num_bytes) {
+    PushUint8(DW_OP_piece);
+    PushUleb128(num_bytes);
+  }
+
+  // Loads 32-bit or 64-bit value depending on architecture.
+  void WriteOpDeref() { PushUint8(DW_OP_deref); }
+
+  // Loads value of given byte size.
+  void WriteOpDerefSize(uint8_t num_bytes) {
+    PushUint8(DW_OP_deref_size);
+    PushUint8(num_bytes);
+  }
+
+  // Pop two values and push their sum.
+  void WriteOpPlus() { PushUint8(DW_OP_plus); }
+
+  // Add constant value to value on top of stack.
+  void WriteOpPlusUconst(uint32_t offset) {
+    PushUint8(DW_OP_plus_uconst);
+    PushUleb128(offset);
+  }
+
+  // Negate top of stack.
+  void WriteOpNeg() { PushUint8(DW_OP_neg); }
+
+  // Pop two values and push their bitwise-AND.
+  void WriteOpAnd() { PushUint8(DW_OP_and); }
+
+  // Push stack base pointer as determined from .debug_frame.
+  void WriteOpCallFrameCfa() { PushUint8(DW_OP_call_frame_cfa); }
+
+  // Push address of the variable we are working with.
+  void WriteOpPushObjectAddress() { PushUint8(DW_OP_push_object_address); }
+
+  // Return the top stack as the value of the variable.
+  // Otherwise, the top of stack is the variable's location.
+  void WriteOpStackValue() { PushUint8(DW_OP_stack_value); }
+
+  explicit Expression(std::vector<uint8_t>* buffer) : Writer<>(buffer) {
+    buffer->clear();
+  }
+};
+}  // namespace dwarf
+}  // namespace art
+
+#endif  // ART_LIBELFFILE_DWARF_EXPRESSION_H_