Add DwarfSection classes.

Bug: 23762183

Test: Ran new unit tests.
Change-Id: Icca2a73c50d467718ba4ac41e1c8f541488620dd
diff --git a/libunwindstack/DwarfSection.h b/libunwindstack/DwarfSection.h
new file mode 100644
index 0000000..e617601
--- /dev/null
+++ b/libunwindstack/DwarfSection.h
@@ -0,0 +1,137 @@
+/*
+ * 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_SECTION_H
+#define _LIBUNWINDSTACK_DWARF_SECTION_H
+
+#include <stdint.h>
+
+#include <iterator>
+#include <unordered_map>
+
+#include "DwarfError.h"
+#include "DwarfLocation.h"
+#include "DwarfMemory.h"
+#include "DwarfStructs.h"
+
+// Forward declarations.
+class Memory;
+class Regs;
+
+class DwarfSection {
+ public:
+  DwarfSection(Memory* memory) : memory_(memory) {}
+  virtual ~DwarfSection() = default;
+
+  class iterator : public std::iterator<std::bidirectional_iterator_tag, DwarfFde*> {
+   public:
+    iterator(DwarfSection* section, size_t index) : section_(section), index_(index) {}
+
+    iterator& operator++() {
+      index_++;
+      return *this;
+    }
+    iterator& operator++(int increment) {
+      index_ += increment;
+      return *this;
+    }
+    iterator& operator--() {
+      index_--;
+      return *this;
+    }
+    iterator& operator--(int decrement) {
+      index_ -= decrement;
+      return *this;
+    }
+
+    bool operator==(const iterator& rhs) { return this->index_ == rhs.index_; }
+    bool operator!=(const iterator& rhs) { return this->index_ != rhs.index_; }
+
+    const DwarfFde* operator*() { return section_->GetFdeFromIndex(index_); }
+
+   private:
+    DwarfSection* section_ = nullptr;
+    size_t index_ = 0;
+  };
+
+  iterator begin() { return iterator(this, 0); }
+  iterator end() { return iterator(this, fde_count_); }
+
+  DwarfError last_error() { return last_error_; }
+
+  virtual bool Init(uint64_t offset, uint64_t size) = 0;
+
+  virtual bool Eval(const DwarfCie*, Memory*, const dwarf_loc_regs_t&, Regs*) = 0;
+
+  virtual bool GetFdeOffsetFromPc(uint64_t pc, uint64_t* fde_offset) = 0;
+
+  virtual bool Log(uint8_t indent, uint64_t pc, uint64_t load_bias, const DwarfFde* fde) = 0;
+
+  virtual const DwarfFde* GetFdeFromIndex(size_t index) = 0;
+
+  const DwarfFde* GetFdeFromPc(uint64_t pc);
+
+  virtual const DwarfFde* GetFdeFromOffset(uint64_t fde_offset) = 0;
+
+  virtual bool GetCfaLocationInfo(uint64_t pc, const DwarfFde* fde, dwarf_loc_regs_t* loc_regs) = 0;
+
+  virtual bool IsCie32(uint32_t value32) = 0;
+
+  virtual bool IsCie64(uint64_t value64) = 0;
+
+  virtual uint64_t GetCieOffsetFromFde32(uint32_t pointer) = 0;
+
+  virtual uint64_t GetCieOffsetFromFde64(uint64_t pointer) = 0;
+
+  virtual uint64_t AdjustPcFromFde(uint64_t pc) = 0;
+
+  bool Step(uint64_t pc, Regs* regs, Memory* process_memory);
+
+ protected:
+  DwarfMemory memory_;
+  DwarfError last_error_ = DWARF_ERROR_NONE;
+
+  uint64_t fde_count_;
+  std::unordered_map<uint64_t, DwarfFde> fde_entries_;
+  std::unordered_map<uint64_t, DwarfCie> cie_entries_;
+  std::unordered_map<uint64_t, dwarf_loc_regs_t> cie_loc_regs_;
+};
+
+template <typename AddressType>
+class DwarfSectionImpl : public DwarfSection {
+ public:
+  DwarfSectionImpl(Memory* memory) : DwarfSection(memory) {}
+  virtual ~DwarfSectionImpl() = default;
+
+  bool Eval(const DwarfCie* cie, Memory* regular_memory, const dwarf_loc_regs_t& loc_regs,
+            Regs* regs) override;
+
+  const DwarfCie* GetCie(uint64_t offset);
+  bool FillInCie(DwarfCie* cie);
+
+  const DwarfFde* GetFdeFromOffset(uint64_t offset) override;
+  bool FillInFde(DwarfFde* fde);
+
+  bool GetCfaLocationInfo(uint64_t pc, const DwarfFde* fde, dwarf_loc_regs_t* loc_regs) override;
+
+  bool Log(uint8_t indent, uint64_t pc, uint64_t load_bias, const DwarfFde* fde) override;
+
+ protected:
+  bool EvalExpression(const DwarfLocation& loc, uint8_t version, Memory* regular_memory,
+                      AddressType* value);
+};
+
+#endif  // _LIBUNWINDSTACK_DWARF_SECTION_H