Add ability to read jit gdb data.

Changes:
- New JitDebug class to handle all of the jit gdb interface.
- Add unit tests for all, along with new offline test using debug data.
- Add new Memory type called MemoryOfflineParts that has multiple
  MemoryOffline objects to support the offline test.
- Update the tools to use the JitDebug object.
- Modify libbacktrace to use the JitDebug, but only looking in libart.so
  and libartd.so.
- Change the Format32Bits to Is32Bit since it's more accurate and I use
  it in a different context where original name didn't make sense.
- Add a new function to find global variables in an elf file
  (GetGlobalVariable).
- Add a new function to determine if a pc is valid for this elf (IsValidPc).

Bug: 68396769

Test: Ran new unit tests. Added new offline test that uses jit debug data.
Test: Ran art test that generates jit data and verified a crash unwinds
Test: through the jit data.
Change-Id: I6e7ee2f5bab2242028a06feece156dff21c0a974

1 files changed, 69 insertions, 0 deletions

diff --git a/libunwindstack/include/unwindstack/JitDebug.h b/libunwindstack/include/unwindstack/JitDebug.h
new file mode 100644
index 0000000..0bcd0b0
--- /dev/null
+++ b/libunwindstack/include/unwindstack/JitDebug.h
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2017 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_JIT_DEBUG_H
+#define _LIBUNWINDSTACK_JIT_DEBUG_H
+
+#include <stdint.h>
+
+#include <memory>
+#include <mutex>
+#include <string>
+#include <vector>
+
+namespace unwindstack {
+
+// Forward declarations.
+class Elf;
+class Maps;
+class Memory;
+enum ArchEnum : uint8_t;
+
+class JitDebug {
+ public:
+  explicit JitDebug(std::shared_ptr<Memory>& memory);
+  JitDebug(std::shared_ptr<Memory>& memory, std::vector<std::string>& search_libs);
+  ~JitDebug();
+
+  Elf* GetElf(Maps* maps, uint64_t pc);
+
+  void SetArch(ArchEnum arch);
+
+ private:
+  void Init(Maps* maps);
+
+  std::shared_ptr<Memory> memory_;
+  uint64_t entry_addr_ = 0;
+  bool initialized_ = false;
+  std::vector<Elf*> elf_list_;
+  std::vector<std::string> search_libs_;
+
+  std::mutex lock_;
+
+  uint64_t (JitDebug::*read_descriptor_func_)(uint64_t) = nullptr;
+  uint64_t (JitDebug::*read_entry_func_)(uint64_t*, uint64_t*) = nullptr;
+
+  uint64_t ReadDescriptor32(uint64_t);
+  uint64_t ReadDescriptor64(uint64_t);
+
+  uint64_t ReadEntry32Pack(uint64_t* start, uint64_t* size);
+  uint64_t ReadEntry32Pad(uint64_t* start, uint64_t* size);
+  uint64_t ReadEntry64(uint64_t* start, uint64_t* size);
+};
+
+}  // namespace unwindstack
+
+#endif  // _LIBUNWINDSTACK_JIT_DEBUG_H