simpleperf: port read_apk and read_apk/read_elf tests to nonlinux.

Also make following small changes:
1. Manage testdata files like libziparchive.
2. Replace StringToPid() with android::base::ParseInt().
3. Add tests in read_elf_test.

Bug: 26962895

Change-Id: I6603e9f3cea3a013e2618ea003790d102739f843

16 files changed, 138 insertions, 73 deletions

diff --git a/simpleperf/Android.mk b/simpleperf/Android.mk
index 17676b35..5c5642bd 100644
--- a/simpleperf/Android.mk
+++ b/simpleperf/Android.mk
@@ -41,19 +41,22 @@ simpleperf_shared_libraries_target := \
 simpleperf_static_libraries_target := \
   libziparchive \
 
-simpleperf_shared_libraries_host := libbase
-
 simpleperf_shared_libraries_host_linux := \
   libbacktrace \
   libbacktrace_offline \
-  libziparchive-host \
 
 simpleperf_shared_libraries_host_darwin := libLLVM
 
 simpleperf_shared_libraries_host_windows := libLLVM
 
-simpleperf_ldlibs_host_linux := -lrt
+simpleperf_static_libraries_host := \
+  libziparchive-host \
+  libbase \
+  liblog \
+  libz \
+  libutils \
 
+simpleperf_ldlibs_host_linux := -lrt
 
 # libsimpleperf
 # =========================================================
@@ -67,6 +70,7 @@ libsimpleperf_src_files := \
   event_attr.cpp \
   event_type.cpp \
   perf_regs.cpp \
+  read_apk.cpp \
   read_elf.cpp \
   record.cpp \
   record_file_reader.cpp \
@@ -82,7 +86,6 @@ libsimpleperf_src_files_linux := \
   environment.cpp \
   event_fd.cpp \
   event_selection_set.cpp \
-  read_apk.cpp \
   record_file_writer.cpp \
   workload.cpp \
 
@@ -103,6 +106,7 @@ LOCAL_SRC_FILES := \
   $(libsimpleperf_src_files) \
   $(libsimpleperf_src_files_linux) \
 
+LOCAL_STATIC_LIBRARIES := $(simpleperf_static_libraries_target)
 LOCAL_SHARED_LIBRARIES := $(simpleperf_shared_libraries_target)
 LOCAL_MULTILIB := first
 include $(LLVM_DEVICE_BUILD_MK)
@@ -121,6 +125,7 @@ LOCAL_SRC_FILES := $(libsimpleperf_src_files)
 LOCAL_SRC_FILES_darwin := $(libsimpleperf_src_files_darwin)
 LOCAL_SRC_FILES_linux := $(libsimpleperf_src_files_linux)
 LOCAL_SRC_FILES_windows := $(libsimpleperf_src_files_windows)
+LOCAL_STATIC_LIBRARIES := $(simpleperf_static_libraries_host)
 LOCAL_SHARED_LIBRARIES := $(simpleperf_shared_libraries_host)
 LOCAL_SHARED_LIBRARIES_darwin := $(simpleperf_shared_libraries_host_darwin)
 LOCAL_SHARED_LIBRARIES_linux := $(simpleperf_shared_libraries_host_linux)
@@ -143,8 +148,8 @@ LOCAL_MODULE_PATH := $(TARGET_OUT_OPTIONAL_EXECUTABLES)
 LOCAL_CPPFLAGS := $(simpleperf_cppflags_target)
 LOCAL_SRC_FILES := main.cpp
 LOCAL_WHOLE_STATIC_LIBRARIES := libsimpleperf
-LOCAL_SHARED_LIBRARIES := $(simpleperf_shared_libraries_target)
 LOCAL_STATIC_LIBRARIES := $(simpleperf_static_libraries_target)
+LOCAL_SHARED_LIBRARIES := $(simpleperf_shared_libraries_target)
 LOCAL_MULTILIB := first
 include $(BUILD_EXECUTABLE)
 
@@ -158,6 +163,7 @@ LOCAL_CPPFLAGS_linux := $(simpleperf_cppflags_host_linux)
 LOCAL_CPPFLAGS_windows := $(simpleperf_cppflags_host_windows)
 LOCAL_SRC_FILES := main.cpp
 LOCAL_WHOLE_STATIC_LIBRARIES := libsimpleperf
+LOCAL_STATIC_LIBRARIES := $(simpleperf_static_libraries_host)
 LOCAL_SHARED_LIBRARIES := $(simpleperf_shared_libraries_host)
 LOCAL_SHARED_LIBRARIES_darwin := $(simpleperf_shared_libraries_host_darwin)
 LOCAL_SHARED_LIBRARIES_linux := $(simpleperf_shared_libraries_host_linux)
@@ -172,6 +178,8 @@ include $(BUILD_HOST_EXECUTABLE)
 simpleperf_unit_test_src_files := \
   command_test.cpp \
   gtest_main.cpp \
+  read_apk_test.cpp \
+  read_elf_test.cpp \
   record_test.cpp \
   sample_tree_test.cpp \
 
@@ -182,8 +190,6 @@ simpleperf_unit_test_src_files_linux := \
   cmd_report_test.cpp \
   cmd_stat_test.cpp \
   environment_test.cpp \
-  read_elf_test.cpp \
-  read_apk_test.cpp \
   record_file_test.cpp \
   workload_test.cpp \
 
@@ -197,8 +203,8 @@ LOCAL_SRC_FILES := \
   $(simpleperf_unit_test_src_files_linux) \
 
 LOCAL_WHOLE_STATIC_LIBRARIES := libsimpleperf
-LOCAL_SHARED_LIBRARIES := $(simpleperf_shared_libraries_target)
 LOCAL_STATIC_LIBRARIES += $(simpleperf_static_libraries_target)
+LOCAL_SHARED_LIBRARIES := $(simpleperf_shared_libraries_target)
 LOCAL_MULTILIB := first
 include $(BUILD_NATIVE_TEST)
 
@@ -213,6 +219,7 @@ LOCAL_CPPFLAGS_windows := $(simpleperf_cppflags_host_windows)
 LOCAL_SRC_FILES := $(simpleperf_unit_test_src_files)
 LOCAL_SRC_FILES_linux := $(simpleperf_unit_test_src_files_linux)
 LOCAL_WHOLE_STATIC_LIBRARIES := libsimpleperf
+LOCAL_STATIC_LIBRARIES := $(simpleperf_static_libraries_host)
 LOCAL_SHARED_LIBRARIES := $(simpleperf_shared_libraries_host)
 LOCAL_SHARED_LIBRARIES_darwin := $(simpleperf_shared_libraries_host_darwin)
 LOCAL_SHARED_LIBRARIES_linux := $(simpleperf_shared_libraries_host_linux)
@@ -225,7 +232,6 @@ include $(BUILD_HOST_NATIVE_TEST)
 # simpleperf_cpu_hotplug_test
 # =========================================================
 simpleperf_cpu_hotplug_test_src_files := \
-  gtest_main.cpp \
   cpu_hotplug_test.cpp \
 
 # simpleperf_cpu_hotplug_test target
@@ -249,6 +255,7 @@ LOCAL_CPPFLAGS := $(simpleperf_cppflags_host)
 LOCAL_CPPFLAGS_linux := $(simpleperf_cppflags_host_linux)
 LOCAL_SRC_FILES := $(simpleperf_cpu_hotplug_test_src_files)
 LOCAL_WHOLE_STATIC_LIBRARIES := libsimpleperf
+LOCAL_STATIC_LIBRARIES := $(simpleperf_static_libraries_host)
 LOCAL_SHARED_LIBRARIES := $(simpleperf_shared_libraries_host)
 LOCAL_SHARED_LIBRARIES_linux := $(simpleperf_shared_libraries_host_linux)
 LOCAL_LDLIBS_linux := $(simpleperf_ldlibs_host_linux)
diff --git a/simpleperf/cmd_report.cpp b/simpleperf/cmd_report.cpp
index 54ec0ee3..b667de69 100644
--- a/simpleperf/cmd_report.cpp
+++ b/simpleperf/cmd_report.cpp
@@ -25,6 +25,7 @@
 #include <vector>
 
 #include <android-base/logging.h>
+#include <android-base/parseint.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
 
@@ -392,9 +393,9 @@ bool ReportCommand::ParseOptions(const std::vector<std::string>& args) {
       }
       std::vector<std::string> strs = android::base::Split(args[i], ",");
       std::vector<int> ids;
-      for (auto& s : strs) {
+      for (const auto& s : strs) {
         int id;
-        if (!StringToPid(s, &id)) {
+        if (!android::base::ParseInt(s.c_str(), &id, 0)) {
           LOG(ERROR) << "invalid id in " << args[i] << " option: " << s;
           return false;
         }
diff --git a/simpleperf/cpu_hotplug_test.cpp b/simpleperf/cpu_hotplug_test.cpp
index 68d4ea73..61cbc80e 100644
--- a/simpleperf/cpu_hotplug_test.cpp
+++ b/simpleperf/cpu_hotplug_test.cpp
@@ -252,3 +252,9 @@ TEST(cpu_offline, offline_while_recording_on_another_cpu) {
     ASSERT_TRUE(event_fd != nullptr);
   }
 }
+
+int main(int argc, char** argv) {
+  InitLogging(argv, android::base::StderrLogger);
+  testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
diff --git a/simpleperf/environment.cpp b/simpleperf/environment.cpp
index 039eed59..8b39881d 100644
--- a/simpleperf/environment.cpp
+++ b/simpleperf/environment.cpp
@@ -27,6 +27,7 @@
 
 #include <android-base/file.h>
 #include <android-base/logging.h>
+#include <android-base/parseint.h>
 #include <android-base/strings.h>
 #include <android-base/stringprintf.h>
 
@@ -305,9 +306,9 @@ static std::vector<pid_t> GetThreadsInProcess(pid_t pid) {
   std::string task_dirname = android::base::StringPrintf("/proc/%d/task", pid);
   std::vector<std::string> subdirs;
   GetEntriesInDir(task_dirname, nullptr, &subdirs);
-  for (auto& name : subdirs) {
+  for (const auto& name : subdirs) {
     int tid;
-    if (!StringToPid(name, &tid)) {
+    if (!android::base::ParseInt(name.c_str(), &tid, 0)) {
       continue;
     }
     result.push_back(tid);
@@ -341,7 +342,7 @@ bool GetThreadComms(std::vector<ThreadComm>* thread_comms) {
   GetEntriesInDir("/proc", nullptr, &subdirs);
   for (auto& name : subdirs) {
     int pid;
-    if (!StringToPid(name, &pid)) {
+    if (!android::base::ParseInt(name.c_str(), &pid, 0)) {
       continue;
     }
     if (!GetThreadComm(pid, thread_comms)) {
@@ -396,9 +397,9 @@ bool GetModuleBuildId(const std::string& module_name, BuildId* build_id) {
 
 bool GetValidThreadsFromProcessString(const std::string& pid_str, std::set<pid_t>* tid_set) {
   std::vector<std::string> strs = android::base::Split(pid_str, ",");
-  for (auto& s : strs) {
+  for (const auto& s : strs) {
     int pid;
-    if (!StringToPid(s, &pid)) {
+    if (!android::base::ParseInt(s.c_str(), &pid, 0)) {
       LOG(ERROR) << "Invalid pid '" << s << "'";
       return false;
     }
@@ -414,9 +415,9 @@ bool GetValidThreadsFromProcessString(const std::string& pid_str, std::set<pid_t
 
 bool GetValidThreadsFromThreadString(const std::string& tid_str, std::set<pid_t>* tid_set) {
   std::vector<std::string> strs = android::base::Split(tid_str, ",");
-  for (auto& s : strs) {
+  for (const auto& s : strs) {
     int tid;
-    if (!StringToPid(s, &tid)) {
+    if (!android::base::ParseInt(s.c_str(), &tid, 0)) {
       LOG(ERROR) << "Invalid tid '" << s << "'";
       return false;
     }
diff --git a/simpleperf/get_test_data.h b/simpleperf/get_test_data.h
new file mode 100644
index 00000000..313da040
--- /dev/null
+++ b/simpleperf/get_test_data.h
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2015 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 SIMPLE_PERF_GET_TEST_DATA_H_
+#define SIMPLE_PERF_GET_TEST_DATA_H_
+
+#include <string>
+
+std::string GetTestData(const std::string& filename);
+
+#endif  // SIMPLE_PERF_GET_TEST_DATA_H_
diff --git a/simpleperf/gtest_main.cpp b/simpleperf/gtest_main.cpp
index 5de802af..04412eaa 100644
--- a/simpleperf/gtest_main.cpp
+++ b/simpleperf/gtest_main.cpp
@@ -18,8 +18,30 @@
 
 #include <android-base/logging.h>
 
+#include "get_test_data.h"
+#include "utils.h"
+
+static std::string testdata_dir;
+
 int main(int argc, char** argv) {
   InitLogging(argv, android::base::StderrLogger);
   testing::InitGoogleTest(&argc, argv);
+  for (int i = 1; i < argc; ++i) {
+    if (strcmp(argv[i], "-t") == 0 && i + 1 < argc) {
+      testdata_dir = argv[i + 1];
+      break;
+    }
+  }
+  if (testdata_dir.empty()) {
+    printf("Usage: simpleperf_unit_test -t <testdata_dir>\n");
+    return 1;
+  }
+  if (testdata_dir.back() != '/') {
+    testdata_dir.push_back('/');
+  }
   return RUN_ALL_TESTS();
 }
+
+std::string GetTestData(const std::string& filename) {
+  return testdata_dir + filename;
+}
diff --git a/simpleperf/read_apk.cpp b/simpleperf/read_apk.cpp
index 5e8077e9..270b3052 100644
--- a/simpleperf/read_apk.cpp
+++ b/simpleperf/read_apk.cpp
@@ -24,22 +24,22 @@
 #include <sys/types.h>
 #include <unistd.h>
 
-#include <iostream>
 #include <map>
 
 #include <android-base/file.h>
 #include <android-base/logging.h>
+#include <ziparchive/zip_archive.h>
 
 #include "read_elf.h"
 #include "utils.h"
-#include "ziparchive/zip_archive.h"
 
 bool IsValidJarOrApkPath(const std::string& filename) {
   static const char zip_preamble[] = {0x50, 0x4b, 0x03, 0x04 };
   if (!IsRegularFile(filename)) {
     return false;
   }
-  FILE* fp = fopen(filename.c_str(), "reb");
+  std::string mode = std::string("rb") + CLOSE_ON_EXEC_MODE;
+  FILE* fp = fopen(filename.c_str(), mode.c_str());
   if (fp == nullptr) {
     return false;
   }
diff --git a/simpleperf/read_apk_test.cpp b/simpleperf/read_apk_test.cpp
index f2234486..5824f4b7 100644
--- a/simpleperf/read_apk_test.cpp
+++ b/simpleperf/read_apk_test.cpp
@@ -17,22 +17,23 @@
 #include "read_apk.h"
 
 #include <gtest/gtest.h>
+#include "get_test_data.h"
 
 static const std::string fibjar = "fibonacci.jar";
 static const std::string jniapk = "has_embedded_native_libs.apk";
 
 TEST(read_apk, IsValidJarOrApkPath) {
   ASSERT_FALSE(IsValidJarOrApkPath("/dev/zero"));
-  ASSERT_FALSE(IsValidJarOrApkPath("/proc/self/exe"));
-  ASSERT_TRUE(IsValidJarOrApkPath(fibjar));
+  ASSERT_FALSE(IsValidJarOrApkPath(GetTestData("elf_file")));
+  ASSERT_TRUE(IsValidJarOrApkPath(GetTestData(fibjar)));
 }
 
 TEST(read_apk, CollectEmbeddedElfInfoFromApk) {
   ApkInspector inspector;
   ASSERT_TRUE(inspector.FindElfInApkByMmapOffset("/dev/null", 0) == nullptr);
-  ASSERT_TRUE(inspector.FindElfInApkByMmapOffset(fibjar, 0) == nullptr);
-  ASSERT_TRUE(inspector.FindElfInApkByMmapOffset(jniapk, 0) == nullptr);
-  EmbeddedElf *ee1 = inspector.FindElfInApkByMmapOffset(jniapk, 0x91000);
+  ASSERT_TRUE(inspector.FindElfInApkByMmapOffset(GetTestData(fibjar), 0) == nullptr);
+  ASSERT_TRUE(inspector.FindElfInApkByMmapOffset(GetTestData(jniapk), 0) == nullptr);
+  EmbeddedElf *ee1 = inspector.FindElfInApkByMmapOffset(GetTestData(jniapk), 0x91000);
   ASSERT_TRUE(ee1 != nullptr);
   ASSERT_EQ(ee1->entry_name(), "lib/armeabi-v7a/libframeworks_coretests_jni.so");
   ASSERT_TRUE(ee1->entry_offset() == 593920);
diff --git a/simpleperf/read_elf.cpp b/simpleperf/read_elf.cpp
index a4e65ff2..03bdcc56 100644
--- a/simpleperf/read_elf.cpp
+++ b/simpleperf/read_elf.cpp
@@ -46,7 +46,7 @@
 
 FileHelper::FileHelper(const char *filename) : fd_(-1)
 {
-  fd_ = TEMP_FAILURE_RETRY(open(filename, O_RDONLY));
+  fd_ = TEMP_FAILURE_RETRY(open(filename, O_RDONLY | O_BINARY));
 }
 
 FileHelper::~FileHelper()
@@ -57,13 +57,7 @@ FileHelper::~FileHelper()
 bool IsValidElfFile(int fd) {
   static const char elf_magic[] = {0x7f, 'E', 'L', 'F'};
   char buf[4];
-  size_t sz4 = 4;
-
-  ssize_t rc = TEMP_FAILURE_RETRY(read(fd, buf, sz4));
-  if (rc < 0 || rc != 4 || memcmp(buf, elf_magic, 4) != 0) {
-    return false;
-  }
-  return true;
+  return android::base::ReadFully(fd, buf, 4) && memcmp(buf, elf_magic, 4) == 0;
 }
 
 bool IsValidElfPath(const std::string& filename) {
diff --git a/simpleperf/read_elf_test.cpp b/simpleperf/read_elf_test.cpp
index 407e7b78..7a5194ea 100644
--- a/simpleperf/read_elf_test.cpp
+++ b/simpleperf/read_elf_test.cpp
@@ -18,19 +18,55 @@
 
 #include <gtest/gtest.h>
 
-static void ParseSymbol(const ElfFileSymbol& symbol, bool* result) {
-  if (symbol.is_func) {
-    *result = true;
-  }
+#include <map>
+#include "get_test_data.h"
+
+static const unsigned char elf_file_build_id[] = {
+    0x76, 0x00, 0x32, 0x9e, 0x31, 0x05, 0x8e, 0x12, 0xb1, 0x45,
+    0xd1, 0x53, 0xef, 0x27, 0xcd, 0x40, 0xe1, 0xa5, 0xf7, 0xb9
+};
+
+TEST(read_elf, GetBuildIdFromElfFile) {
+  BuildId build_id;
+  ASSERT_TRUE(GetBuildIdFromElfFile(GetTestData("elf_file"), &build_id));
+  ASSERT_EQ(build_id, BuildId(elf_file_build_id));
 }
 
-TEST(read_elf, parse_symbols_from_elf_file) {
+static void ParseSymbol(const ElfFileSymbol& symbol, std::map<std::string, ElfFileSymbol>* symbols) {
+  (*symbols)[symbol.name] = symbol;
+}
+
+static void CheckElfFileSymbols(const std::map<std::string, ElfFileSymbol>& symbols) {
+  auto pos = symbols.find("GlobalVar");
+  ASSERT_NE(pos, symbols.end());
+  ASSERT_FALSE(pos->second.is_func);
+  pos = symbols.find("GlobalFunc");
+  ASSERT_NE(pos, symbols.end());
+  ASSERT_TRUE(pos->second.is_func);
+  ASSERT_TRUE(pos->second.is_in_text_section);
+}
+
+TEST(read_elf, parse_symbols_from_elf_file_with_correct_build_id) {
+  BuildId build_id(elf_file_build_id);
+  std::map<std::string, ElfFileSymbol> symbols;
+  ASSERT_TRUE(ParseSymbolsFromElfFile(GetTestData("elf_file"), build_id,
+                                      std::bind(ParseSymbol, std::placeholders::_1, &symbols)));
+  CheckElfFileSymbols(symbols);
+}
+
+TEST(read_elf, parse_symbols_from_elf_file_without_build_id) {
   BuildId build_id;
-  GetBuildIdFromElfFile("proc/self/exe", &build_id);
-  bool result = false;
-  ASSERT_TRUE(ParseSymbolsFromElfFile("/proc/self/exe", build_id,
-                                      std::bind(ParseSymbol, std::placeholders::_1, &result)));
-  ASSERT_TRUE(result);
+  std::map<std::string, ElfFileSymbol> symbols;
+  ASSERT_TRUE(ParseSymbolsFromElfFile(GetTestData("elf_file"), build_id,
+                                      std::bind(ParseSymbol, std::placeholders::_1, &symbols)));
+  CheckElfFileSymbols(symbols);
+}
+
+TEST(read_elf, parse_symbols_from_elf_file_with_wrong_build_id) {
+  BuildId build_id("wrong_build_id");
+  std::map<std::string, ElfFileSymbol> symbols;
+  ASSERT_FALSE(ParseSymbolsFromElfFile(GetTestData("elf_file"), build_id,
+                                       std::bind(ParseSymbol, std::placeholders::_1, &symbols)));
 }
 
 TEST(read_elf, arm_mapping_symbol) {
@@ -43,5 +79,5 @@ TEST(read_elf, arm_mapping_symbol) {
 TEST(read_elf, IsValidElfPath) {
   ASSERT_FALSE(IsValidElfPath("/dev/zero"));
   ASSERT_FALSE(IsValidElfPath("/sys/devices/system/cpu/online"));
-  ASSERT_TRUE(IsValidElfPath("/proc/self/exe"));
+  ASSERT_TRUE(IsValidElfPath(GetTestData("elf_file")));
 }
diff --git a/simpleperf/test_inputs/Android.mk b/simpleperf/test_inputs/Android.mk
deleted file mode 100644
index 6f565c1c..00000000
--- a/simpleperf/test_inputs/Android.mk
+++ /dev/null
@@ -1,20 +0,0 @@
-
-# some data files used by simpleperf_unit_test
-
-LOCAL_PATH := $(call my-dir)
-
-include $(CLEAR_VARS)
-LOCAL_MODULE := fibonacci.jar
-LOCAL_MODULE_TAGS := optional
-LOCAL_MODULE_CLASS := DATA
-LOCAL_MODULE_PATH := $(TARGET_OUT_DATA_NATIVE_TESTS)/simpleperf_unit_test
-LOCAL_SRC_FILES := fibonacci.jar
-include $(BUILD_PREBUILT)
-
-include $(CLEAR_VARS)
-LOCAL_MODULE := has_embedded_native_libs.apk
-LOCAL_MODULE_TAGS := optional
-LOCAL_MODULE_CLASS := DATA
-LOCAL_MODULE_PATH := $(TARGET_OUT_DATA_NATIVE_TESTS)/simpleperf_unit_test
-LOCAL_SRC_FILES := has_embedded_native_libs.apk
-include $(BUILD_PREBUILT)
diff --git a/simpleperf/testdata/elf_file b/simpleperf/testdata/elf_file
new file mode 100644
index 00000000..53b589a5
--- /dev/null
+++ b/simpleperf/testdata/elf_file
diff --git a/simpleperf/test_inputs/fibonacci.jar b/simpleperf/testdata/fibonacci.jar
index df57e40f..df57e40f 100644
--- a/simpleperf/test_inputs/fibonacci.jar
+++ b/simpleperf/testdata/fibonacci.jar
diff --git a/simpleperf/test_inputs/has_embedded_native_libs.apk b/simpleperf/testdata/has_embedded_native_libs.apk
index 2a1924cd..2a1924cd 100644
--- a/simpleperf/test_inputs/has_embedded_native_libs.apk
+++ b/simpleperf/testdata/has_embedded_native_libs.apk
diff --git a/simpleperf/utils.cpp b/simpleperf/utils.cpp
index ae157b53..eabad29f 100644
--- a/simpleperf/utils.cpp
+++ b/simpleperf/utils.cpp
@@ -114,9 +114,3 @@ bool IsRegularFile(const std::string& filename) {
   }
   return false;
 }
-
-bool StringToPid(const std::string& s, int* pid) {
-  char* endptr;
-  *pid = static_cast<int>(strtol(s.c_str(), &endptr, 10));
-  return *endptr == '\0';
-}
diff --git a/simpleperf/utils.h b/simpleperf/utils.h
index c63ac6c2..2ce0726d 100644
--- a/simpleperf/utils.h
+++ b/simpleperf/utils.h
@@ -66,6 +66,5 @@ void GetEntriesInDir(const std::string& dirpath, std::vector<std::string>* files
                      std::vector<std::string>* subdirs);
 bool IsDir(const std::string& dirpath);
 bool IsRegularFile(const std::string& filename);
-bool StringToPid(const std::string& s, int* pid);
 
 #endif  // SIMPLE_PERF_UTILS_H_