Optimize Memory::ReadString
This function is responsible for majority of CPU time in prefetto.
Reduce the number of memory reads (don't read strings byte-by-byte).
Update all calls of ReadString to include the third parameter to have
a max read.
Add an Elf creation benchmark since this function is on the elf
creation path.
Test: libunwindstack_unit_test
Change-Id: Ia36e1f1a5ba76c9e9f13c43fb9e3691dde7897f2
diff --git a/libunwindstack/benchmarks/Utils.h b/libunwindstack/benchmarks/Utils.h
new file mode 100644
index 0000000..bee6efc
--- /dev/null
+++ b/libunwindstack/benchmarks/Utils.h
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2020 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_UTILS_H
+#define _LIBUNWINDSTACK_UTILS_H
+
+#include <stdint.h>
+
+#include <string>
+
+std::string GetElfFile();
+
+std::string GetSymbolSortedElfFile();
+
+std::string GetCompressedElfFile();
+
+#if defined(__BIONIC__)
+
+#include <meminfo/procmeminfo.h>
+#include <procinfo/process_map.h>
+
+void GatherRss(uint64_t* rss_bytes);
+
+#endif
+
+#endif // _LIBUNWINDSTACK_UTILS_h