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/headers.h b/compiler/debug/dwarf/headers.h
new file mode 100644
index 0000000..146d9fd
--- /dev/null
+++ b/compiler/debug/dwarf/headers.h
@@ -0,0 +1,207 @@
+/*
+ * 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_HEADERS_H_
+#define ART_COMPILER_DEBUG_DWARF_HEADERS_H_
+
+#include <cstdint>
+
+#include "debug/dwarf/debug_frame_opcode_writer.h"
+#include "debug/dwarf/debug_info_entry_writer.h"
+#include "debug/dwarf/debug_line_opcode_writer.h"
+#include "debug/dwarf/dwarf_constants.h"
+#include "debug/dwarf/register.h"
+#include "debug/dwarf/writer.h"
+#include "utils/array_ref.h"
+
+namespace art {
+namespace dwarf {
+
+// Note that all headers start with 32-bit length.
+// DWARF also supports 64-bit lengths, but we never use that.
+// It is intended to support very large debug sections (>4GB),
+// and compilers are expected *not* to use it by default.
+// In particular, it is not related to machine architecture.
+
+// Write common information entry (CIE) to .debug_frame or .eh_frame section.
+template<typename Vector>
+void WriteCIE(bool is64bit,
+              Reg return_address_register,
+              const DebugFrameOpCodeWriter<Vector>& opcodes,
+              CFIFormat format,
+              std::vector<uint8_t>* buffer) {
+  static_assert(std::is_same<typename Vector::value_type, uint8_t>::value, "Invalid value type");
+
+  Writer<> writer(buffer);
+  size_t cie_header_start_ = writer.data()->size();
+  writer.PushUint32(0);  // Length placeholder.
+  writer.PushUint32((format == DW_EH_FRAME_FORMAT) ? 0 : 0xFFFFFFFF);  // CIE id.
+  writer.PushUint8(1);   // Version.
+  writer.PushString("zR");
+  writer.PushUleb128(DebugFrameOpCodeWriter<Vector>::kCodeAlignmentFactor);
+  writer.PushSleb128(DebugFrameOpCodeWriter<Vector>::kDataAlignmentFactor);
+  writer.PushUleb128(return_address_register.num());  // ubyte in DWARF2.
+  writer.PushUleb128(1);  // z: Augmentation data size.
+  if (is64bit) {
+    if (format == DW_EH_FRAME_FORMAT) {
+      writer.PushUint8(DW_EH_PE_pcrel | DW_EH_PE_sdata8);   // R: Pointer encoding.
+    } else {
+      DCHECK(format == DW_DEBUG_FRAME_FORMAT);
+      writer.PushUint8(DW_EH_PE_absptr | DW_EH_PE_udata8);  // R: Pointer encoding.
+    }
+  } else {
+    if (format == DW_EH_FRAME_FORMAT) {
+      writer.PushUint8(DW_EH_PE_pcrel | DW_EH_PE_sdata4);   // R: Pointer encoding.
+    } else {
+      DCHECK(format == DW_DEBUG_FRAME_FORMAT);
+      writer.PushUint8(DW_EH_PE_absptr | DW_EH_PE_udata4);  // R: Pointer encoding.
+    }
+  }
+  writer.PushData(opcodes.data());
+  writer.Pad(is64bit ? 8 : 4);
+  writer.UpdateUint32(cie_header_start_, writer.data()->size() - cie_header_start_ - 4);
+}
+
+// Write frame description entry (FDE) to .debug_frame or .eh_frame section.
+inline
+void WriteFDE(bool is64bit,
+              uint64_t section_address,  // Absolute address of the section.
+              uint64_t cie_address,  // Absolute address of last CIE.
+              uint64_t code_address,
+              uint64_t code_size,
+              const ArrayRef<const uint8_t>& opcodes,
+              CFIFormat format,
+              uint64_t buffer_address,  // Address of buffer in linked application.
+              std::vector<uint8_t>* buffer,
+              std::vector<uintptr_t>* patch_locations) {
+  CHECK_GE(cie_address, section_address);
+  CHECK_GE(buffer_address, section_address);
+
+  Writer<> writer(buffer);
+  size_t fde_header_start = writer.data()->size();
+  writer.PushUint32(0);  // Length placeholder.
+  if (format == DW_EH_FRAME_FORMAT) {
+    uint32_t cie_pointer = (buffer_address + buffer->size()) - cie_address;
+    writer.PushUint32(cie_pointer);
+  } else {
+    DCHECK(format == DW_DEBUG_FRAME_FORMAT);
+    uint32_t cie_pointer = cie_address - section_address;
+    writer.PushUint32(cie_pointer);
+  }
+  if (format == DW_EH_FRAME_FORMAT) {
+    // .eh_frame encodes the location as relative address.
+    code_address -= buffer_address + buffer->size();
+  } else {
+    DCHECK(format == DW_DEBUG_FRAME_FORMAT);
+    // Relocate code_address if it has absolute value.
+    patch_locations->push_back(buffer_address + buffer->size() - section_address);
+  }
+  if (is64bit) {
+    writer.PushUint64(code_address);
+    writer.PushUint64(code_size);
+  } else {
+    writer.PushUint32(code_address);
+    writer.PushUint32(code_size);
+  }
+  writer.PushUleb128(0);  // Augmentation data size.
+  writer.PushData(opcodes.data(), opcodes.size());
+  writer.Pad(is64bit ? 8 : 4);
+  writer.UpdateUint32(fde_header_start, writer.data()->size() - fde_header_start - 4);
+}
+
+// Write compilation unit (CU) to .debug_info section.
+template<typename Vector>
+void WriteDebugInfoCU(uint32_t debug_abbrev_offset,
+                      const DebugInfoEntryWriter<Vector>& entries,
+                      size_t debug_info_offset,  // offset from start of .debug_info.
+                      std::vector<uint8_t>* debug_info,
+                      std::vector<uintptr_t>* debug_info_patches) {
+  static_assert(std::is_same<typename Vector::value_type, uint8_t>::value, "Invalid value type");
+
+  Writer<> writer(debug_info);
+  size_t start = writer.data()->size();
+  writer.PushUint32(0);  // Length placeholder.
+  writer.PushUint16(4);  // Version.
+  writer.PushUint32(debug_abbrev_offset);
+  writer.PushUint8(entries.Is64bit() ? 8 : 4);
+  size_t entries_offset = writer.data()->size();
+  DCHECK_EQ(entries_offset, DebugInfoEntryWriter<Vector>::kCompilationUnitHeaderSize);
+  writer.PushData(entries.data());
+  writer.UpdateUint32(start, writer.data()->size() - start - 4);
+  // Copy patch locations and make them relative to .debug_info section.
+  for (uintptr_t patch_location : entries.GetPatchLocations()) {
+    debug_info_patches->push_back(debug_info_offset + entries_offset + patch_location);
+  }
+}
+
+struct FileEntry {
+  std::string file_name;
+  int directory_index;
+  int modification_time;
+  int file_size;
+};
+
+// Write line table to .debug_line section.
+template<typename Vector>
+void WriteDebugLineTable(const std::vector<std::string>& include_directories,
+                         const std::vector<FileEntry>& files,
+                         const DebugLineOpCodeWriter<Vector>& opcodes,
+                         size_t debug_line_offset,  // offset from start of .debug_line.
+                         std::vector<uint8_t>* debug_line,
+                         std::vector<uintptr_t>* debug_line_patches) {
+  static_assert(std::is_same<typename Vector::value_type, uint8_t>::value, "Invalid value type");
+
+  Writer<> writer(debug_line);
+  size_t header_start = writer.data()->size();
+  writer.PushUint32(0);  // Section-length placeholder.
+  writer.PushUint16(3);  // .debug_line version.
+  size_t header_length_pos = writer.data()->size();
+  writer.PushUint32(0);  // Header-length placeholder.
+  writer.PushUint8(1 << opcodes.GetCodeFactorBits());
+  writer.PushUint8(DebugLineOpCodeWriter<Vector>::kDefaultIsStmt ? 1 : 0);
+  writer.PushInt8(DebugLineOpCodeWriter<Vector>::kLineBase);
+  writer.PushUint8(DebugLineOpCodeWriter<Vector>::kLineRange);
+  writer.PushUint8(DebugLineOpCodeWriter<Vector>::kOpcodeBase);
+  static const int opcode_lengths[DebugLineOpCodeWriter<Vector>::kOpcodeBase] = {
+      0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1 };
+  for (int i = 1; i < DebugLineOpCodeWriter<Vector>::kOpcodeBase; i++) {
+    writer.PushUint8(opcode_lengths[i]);
+  }
+  for (const std::string& directory : include_directories) {
+    writer.PushData(directory.data(), directory.size() + 1);
+  }
+  writer.PushUint8(0);  // Terminate include_directories list.
+  for (const FileEntry& file : files) {
+    writer.PushData(file.file_name.data(), file.file_name.size() + 1);
+    writer.PushUleb128(file.directory_index);
+    writer.PushUleb128(file.modification_time);
+    writer.PushUleb128(file.file_size);
+  }
+  writer.PushUint8(0);  // Terminate file list.
+  writer.UpdateUint32(header_length_pos, writer.data()->size() - header_length_pos - 4);
+  size_t opcodes_offset = writer.data()->size();
+  writer.PushData(opcodes.data());
+  writer.UpdateUint32(header_start, writer.data()->size() - header_start - 4);
+  // Copy patch locations and make them relative to .debug_line section.
+  for (uintptr_t patch_location : opcodes.GetPatchLocations()) {
+    debug_line_patches->push_back(debug_line_offset + opcodes_offset + patch_location);
+  }
+}
+
+}  // namespace dwarf
+}  // namespace art
+
+#endif  // ART_COMPILER_DEBUG_DWARF_HEADERS_H_