Add a global elf cache.

Bug: 65682279

Test: Ran new unit tests.
Change-Id: I19c64614b2b11a27f58204d4cc34913c02e04c36

2 files changed, 16 insertions, 2 deletions

diff --git a/libunwindstack/include/unwindstack/Elf.h b/libunwindstack/include/unwindstack/Elf.h
index e562d6d..a874709 100644
--- a/libunwindstack/include/unwindstack/Elf.h
+++ b/libunwindstack/include/unwindstack/Elf.h
@@ -22,6 +22,7 @@
 #include <memory>
 #include <mutex>
 #include <string>
+#include <unordered_map>
 
 #include <unwindstack/ElfInterface.h>
 #include <unwindstack/Memory.h>
@@ -96,6 +97,14 @@ class Elf {
 
   static uint64_t GetLoadBias(Memory* memory);
 
+  static void SetCachingEnabled(bool enable);
+  static bool CachingEnabled() { return cache_enabled_; }
+
+  static void CacheLock();
+  static void CacheUnlock();
+  static void CacheAdd(MapInfo* info);
+  static bool CacheGet(const std::string& name, std::shared_ptr<Elf>* elf);
+
  protected:
   bool valid_ = false;
   uint64_t load_bias_ = 0;
@@ -109,6 +118,10 @@ class Elf {
 
   std::unique_ptr<Memory> gnu_debugdata_memory_;
   std::unique_ptr<ElfInterface> gnu_debugdata_interface_;
+
+  static bool cache_enabled_;
+  static std::unordered_map<std::string, std::shared_ptr<Elf>>* cache_;
+  static std::mutex* cache_lock_;
 };
 
 }  // namespace unwindstack
diff --git a/libunwindstack/include/unwindstack/MapInfo.h b/libunwindstack/include/unwindstack/MapInfo.h
index 22e48f7..a57fe68 100644
--- a/libunwindstack/include/unwindstack/MapInfo.h
+++ b/libunwindstack/include/unwindstack/MapInfo.h
@@ -20,6 +20,7 @@
 #include <stdint.h>
 
 #include <atomic>
+#include <memory>
 #include <mutex>
 #include <string>
 
@@ -40,14 +41,14 @@ struct MapInfo {
         flags(flags),
         name(name),
         load_bias(static_cast<uint64_t>(-1)) {}
-  ~MapInfo() { delete elf; }
+  ~MapInfo() = default;
 
   uint64_t start = 0;
   uint64_t end = 0;
   uint64_t offset = 0;
   uint16_t flags = 0;
   std::string name;
-  Elf* elf = nullptr;
+  std::shared_ptr<Elf> elf;
   // This value is only non-zero if the offset is non-zero but there is
   // no elf signature found at that offset. This indicates that the
   // entire file is represented by the Memory object returned by CreateMemory,