Move code related to debug info generation to its own directory.

debug/dwarf/ contains helper classes which hide the details
of the DWARF file format. It acts as independent DWARF library.

debug/ contains ART-specific code which generates ELF debug
sections (which includes non-DWARF sections like .symtab).

Change-Id: Id351f604e4e64be2ca395a78324ea02e30481497
diff --git a/compiler/debug/dwarf/writer.h b/compiler/debug/dwarf/writer.h
new file mode 100644
index 0000000..95912ad
--- /dev/null
+++ b/compiler/debug/dwarf/writer.h
@@ -0,0 +1,182 @@
+/*
+ * Copyright (C) 2015 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_COMPILER_DEBUG_DWARF_WRITER_H_
+#define ART_COMPILER_DEBUG_DWARF_WRITER_H_
+
+#include <type_traits>
+#include <vector>
+#include "base/bit_utils.h"
+#include "base/logging.h"
+#include "leb128.h"
+
+namespace art {
+namespace dwarf {
+
+// The base class for all DWARF writers.
+template <typename Vector = std::vector<uint8_t>>
+class Writer {
+  static_assert(std::is_same<typename Vector::value_type, uint8_t>::value, "Invalid value type");
+
+ public:
+  void PushUint8(int value) {
+    DCHECK_GE(value, 0);
+    DCHECK_LE(value, UINT8_MAX);
+    data_->push_back(value & 0xff);
+  }
+
+  void PushUint16(int value) {
+    DCHECK_GE(value, 0);
+    DCHECK_LE(value, UINT16_MAX);
+    data_->push_back((value >> 0) & 0xff);
+    data_->push_back((value >> 8) & 0xff);
+  }
+
+  void PushUint32(uint32_t value) {
+    data_->push_back((value >> 0) & 0xff);
+    data_->push_back((value >> 8) & 0xff);
+    data_->push_back((value >> 16) & 0xff);
+    data_->push_back((value >> 24) & 0xff);
+  }
+
+  void PushUint32(int value) {
+    DCHECK_GE(value, 0);
+    PushUint32(static_cast<uint32_t>(value));
+  }
+
+  void PushUint32(uint64_t value) {
+    DCHECK_LE(value, UINT32_MAX);
+    PushUint32(static_cast<uint32_t>(value));
+  }
+
+  void PushUint64(uint64_t value) {
+    data_->push_back((value >> 0) & 0xff);
+    data_->push_back((value >> 8) & 0xff);
+    data_->push_back((value >> 16) & 0xff);
+    data_->push_back((value >> 24) & 0xff);
+    data_->push_back((value >> 32) & 0xff);
+    data_->push_back((value >> 40) & 0xff);
+    data_->push_back((value >> 48) & 0xff);
+    data_->push_back((value >> 56) & 0xff);
+  }
+
+  void PushInt8(int value) {
+    DCHECK_GE(value, INT8_MIN);
+    DCHECK_LE(value, INT8_MAX);
+    PushUint8(static_cast<uint8_t>(value));
+  }
+
+  void PushInt16(int value) {
+    DCHECK_GE(value, INT16_MIN);
+    DCHECK_LE(value, INT16_MAX);
+    PushUint16(static_cast<uint16_t>(value));
+  }
+
+  void PushInt32(int value) {
+    PushUint32(static_cast<uint32_t>(value));
+  }
+
+  void PushInt64(int64_t value) {
+    PushUint64(static_cast<uint64_t>(value));
+  }
+
+  // Variable-length encoders.
+
+  void PushUleb128(uint32_t value) {
+    EncodeUnsignedLeb128(data_, value);
+  }
+
+  void PushUleb128(int value) {
+    DCHECK_GE(value, 0);
+    EncodeUnsignedLeb128(data_, value);
+  }
+
+  void PushSleb128(int value) {
+    EncodeSignedLeb128(data_, value);
+  }
+
+  // Miscellaneous functions.
+
+  void PushString(const char* value) {
+    data_->insert(data_->end(), value, value + strlen(value) + 1);
+  }
+
+  void PushData(const uint8_t* ptr, size_t num_bytes) {
+    data_->insert(data_->end(), ptr, ptr + num_bytes);
+  }
+
+  void PushData(const char* ptr, size_t num_bytes) {
+    data_->insert(data_->end(), ptr, ptr + num_bytes);
+  }
+
+  void PushData(const Vector* buffer) {
+    data_->insert(data_->end(), buffer->begin(), buffer->end());
+  }
+
+  void UpdateUint32(size_t offset, uint32_t value) {
+    DCHECK_LT(offset + 3, data_->size());
+    (*data_)[offset + 0] = (value >> 0) & 0xFF;
+    (*data_)[offset + 1] = (value >> 8) & 0xFF;
+    (*data_)[offset + 2] = (value >> 16) & 0xFF;
+    (*data_)[offset + 3] = (value >> 24) & 0xFF;
+  }
+
+  void UpdateUint64(size_t offset, uint64_t value) {
+    DCHECK_LT(offset + 7, data_->size());
+    (*data_)[offset + 0] = (value >> 0) & 0xFF;
+    (*data_)[offset + 1] = (value >> 8) & 0xFF;
+    (*data_)[offset + 2] = (value >> 16) & 0xFF;
+    (*data_)[offset + 3] = (value >> 24) & 0xFF;
+    (*data_)[offset + 4] = (value >> 32) & 0xFF;
+    (*data_)[offset + 5] = (value >> 40) & 0xFF;
+    (*data_)[offset + 6] = (value >> 48) & 0xFF;
+    (*data_)[offset + 7] = (value >> 56) & 0xFF;
+  }
+
+  void UpdateUleb128(size_t offset, uint32_t value) {
+    DCHECK_LE(offset + UnsignedLeb128Size(value), data_->size());
+    UpdateUnsignedLeb128(data_->data() + offset, value);
+  }
+
+  void Pop() {
+    return data_->pop_back();
+  }
+
+  void Pad(int alignment) {
+    DCHECK_NE(alignment, 0);
+    data_->resize(RoundUp(data_->size(), alignment), 0);
+  }
+
+  const Vector* data() const {
+    return data_;
+  }
+
+  size_t size() const {
+    return data_->size();
+  }
+
+  explicit Writer(Vector* buffer) : data_(buffer) { }
+
+ private:
+  Vector* const data_;
+
+  DISALLOW_COPY_AND_ASSIGN(Writer);
+};
+
+}  // namespace dwarf
+}  // namespace art
+
+#endif  // ART_COMPILER_DEBUG_DWARF_WRITER_H_