Add support for caching small reads.

Add benchmarking to verify this is faster.

Test: Ran unit tests.
Change-Id: I1487114331f4581ec2368e56c4f18c6e3e6bcc7d
diff --git a/libunwindstack/Android.bp b/libunwindstack/Android.bp
index 14f82c7..a5e0dc9 100644
--- a/libunwindstack/Android.bp
+++ b/libunwindstack/Android.bp
@@ -184,6 +184,7 @@
         "tests/MapInfoGetLoadBiasTest.cpp",
         "tests/MapsTest.cpp",
         "tests/MemoryBufferTest.cpp",
+        "tests/MemoryCacheTest.cpp",
         "tests/MemoryFake.cpp",
         "tests/MemoryFileTest.cpp",
         "tests/MemoryLocalTest.cpp",
@@ -310,6 +311,28 @@
     ],
 }
 
+//-------------------------------------------------------------------------
+// Benchmarks
+//-------------------------------------------------------------------------
+cc_benchmark {
+    name: "unwind_benchmarks",
+    host_supported: true,
+    defaults: ["libunwindstack_flags"],
+
+    // Disable optimizations so that all of the calls are not optimized away.
+    cflags: [
+        "-O0",
+    ],
+
+    srcs: [
+        "benchmarks/unwind_benchmarks.cpp",
+    ],
+
+    shared_libs: [
+        "libunwindstack",
+    ],
+}
+
 // Generates the elf data for use in the tests for .gnu_debugdata frames.
 // Once these files are generated, use the xz command to compress the data.
 cc_binary_host {