Add support for only a .eh_frame.

Static executables only have a .eh_frame section and no .eh_frame_hdr
section. Add support for this by rearranging the class hierarchy and
creating a DwarfEhFrameWithHdr class and a DwarfEhFrame class to handle
the different cases.

Add new unit tests for DwarfEhFrame and for the new functionality.

Bug: 68820189

Test: Passes new unit tests, unwinds static executables.
Change-Id: I63d7cb8c52a686e96579a2266e18c0d06bbb6e63
diff --git a/libunwindstack/DwarfEhFrameWithHdr.h b/libunwindstack/DwarfEhFrameWithHdr.h
new file mode 100644
index 0000000..3571166
--- /dev/null
+++ b/libunwindstack/DwarfEhFrameWithHdr.h
@@ -0,0 +1,78 @@
+/*
+ * 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 _LIBUNWINDSTACK_DWARF_EH_FRAME_WITH_HDR_H
+#define _LIBUNWINDSTACK_DWARF_EH_FRAME_WITH_HDR_H
+
+#include <stdint.h>
+
+#include <unordered_map>
+
+#include "DwarfEhFrame.h"
+
+namespace unwindstack {
+
+// Forward declarations.
+class Memory;
+
+template <typename AddressType>
+class DwarfEhFrameWithHdr : public DwarfEhFrame<AddressType> {
+ public:
+  // Add these so that the protected members of DwarfSectionImpl
+  // can be accessed without needing a this->.
+  using DwarfSectionImpl<AddressType>::memory_;
+  using DwarfSectionImpl<AddressType>::fde_count_;
+  using DwarfSectionImpl<AddressType>::entries_offset_;
+  using DwarfSectionImpl<AddressType>::entries_end_;
+  using DwarfSectionImpl<AddressType>::last_error_;
+
+  struct FdeInfo {
+    AddressType pc;
+    uint64_t offset;
+  };
+
+  DwarfEhFrameWithHdr(Memory* memory) : DwarfEhFrame<AddressType>(memory) {}
+  virtual ~DwarfEhFrameWithHdr() = default;
+
+  bool Init(uint64_t offset, uint64_t size) override;
+
+  bool GetFdeOffsetFromPc(uint64_t pc, uint64_t* fde_offset) override;
+
+  const DwarfFde* GetFdeFromIndex(size_t index) override;
+
+  const FdeInfo* GetFdeInfoFromIndex(size_t index);
+
+  bool GetFdeOffsetSequential(uint64_t pc, uint64_t* fde_offset);
+
+  bool GetFdeOffsetBinary(uint64_t pc, uint64_t* fde_offset, uint64_t total_entries);
+
+ protected:
+  uint8_t version_;
+  uint8_t ptr_encoding_;
+  uint8_t table_encoding_;
+  size_t table_entry_size_;
+
+  uint64_t ptr_offset_;
+
+  uint64_t entries_data_offset_;
+  uint64_t cur_entries_offset_ = 0;
+
+  std::unordered_map<uint64_t, FdeInfo> fde_info_;
+};
+
+}  // namespace unwindstack
+
+#endif  // _LIBUNWINDSTACK_DWARF_EH_FRAME_WITH_HDR_H