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* Copyright (C) 2011 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
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
#include <pthread.h>
#include <stdlib.h>
#include <limits>
#include <memory>
#include <random>
#include <string>
#include <type_traits>
#include <vector>
#include "arch/instruction_set.h"
#include "base/casts.h"
#include "base/logging.h"
#include "base/mutex.h"
#include "base/stringpiece.h"
#include "globals.h"
#include "primitive.h"
class BacktraceMap;
namespace art {
class ArtField;
class ArtMethod;
class DexFile;
namespace mirror {
class Class;
class Object;
class String;
} // namespace mirror
template <typename T>
bool ParseUint(const char *in, T* out) {
char* end;
unsigned long long int result = strtoull(in, &end, 0); // NOLINT(runtime/int)
if (in == end || *end != '\0') {
return false;
if (std::numeric_limits<T>::max() < result) {
return false;
*out = static_cast<T>(result);
return true;
template <typename T>
bool ParseInt(const char* in, T* out) {
char* end;
long long int result = strtoll(in, &end, 0); // NOLINT(runtime/int)
if (in == end || *end != '\0') {
return false;
if (result < std::numeric_limits<T>::min() || std::numeric_limits<T>::max() < result) {
return false;
*out = static_cast<T>(result);
return true;
// Return whether x / divisor == x * (1.0f / divisor), for every float x.
static constexpr bool CanDivideByReciprocalMultiplyFloat(int32_t divisor) {
// True, if the most significant bits of divisor are 0.
return ((divisor & 0x7fffff) == 0);
// Return whether x / divisor == x * (1.0 / divisor), for every double x.
static constexpr bool CanDivideByReciprocalMultiplyDouble(int64_t divisor) {
// True, if the most significant bits of divisor are 0.
return ((divisor & ((UINT64_C(1) << 52) - 1)) == 0);
static inline uint32_t PointerToLowMemUInt32(const void* p) {
uintptr_t intp = reinterpret_cast<uintptr_t>(p);
return intp & 0xFFFFFFFFU;
static inline bool NeedsEscaping(uint16_t ch) {
return (ch < ' ' || ch > '~');
template <typename T> T SafeAbs(T value) {
// std::abs has undefined behavior on min limits.
DCHECK_NE(value, std::numeric_limits<T>::min());
return std::abs(value);
template <typename T> T AbsOrMin(T value) {
return (value == std::numeric_limits<T>::min())
? value
: std::abs(value);
template <typename T>
inline typename std::make_unsigned<T>::type MakeUnsigned(T x) {
return static_cast<typename std::make_unsigned<T>::type>(x);
std::string PrintableChar(uint16_t ch);
// Returns an ASCII string corresponding to the given UTF-8 string.
// Java escapes are used for non-ASCII characters.
std::string PrintableString(const char* utf8);
// Tests whether 's' starts with 'prefix'.
bool StartsWith(const std::string& s, const char* prefix);
// Tests whether 's' ends with 'suffix'.
bool EndsWith(const std::string& s, const char* suffix);
// Used to implement PrettyClass, PrettyField, PrettyMethod, and PrettyTypeOf,
// one of which is probably more useful to you.
// Returns a human-readable equivalent of 'descriptor'. So "I" would be "int",
// "[[I" would be "int[][]", "[Ljava/lang/String;" would be
// "java.lang.String[]", and so forth.
std::string PrettyDescriptor(mirror::String* descriptor)
std::string PrettyDescriptor(const char* descriptor);
std::string PrettyDescriptor(mirror::Class* klass)
std::string PrettyDescriptor(Primitive::Type type);
// Returns a human-readable signature for 'f'. Something like "a.b.C.f" or
// "int a.b.C.f" (depending on the value of 'with_type').
std::string PrettyField(ArtField* f, bool with_type = true)
std::string PrettyField(uint32_t field_idx, const DexFile& dex_file, bool with_type = true);
// Returns a human-readable signature for 'm'. Something like "a.b.C.m" or
// "a.b.C.m(II)V" (depending on the value of 'with_signature').
std::string PrettyMethod(ArtMethod* m, bool with_signature = true)
std::string PrettyMethod(uint32_t method_idx, const DexFile& dex_file, bool with_signature = true);
// Returns a human-readable form of the name of the *class* of the given object.
// So given an instance of java.lang.String, the output would
// be "java.lang.String". Given an array of int, the output would be "int[]".
// Given String.class, the output would be "java.lang.Class<java.lang.String>".
std::string PrettyTypeOf(mirror::Object* obj)
// Returns a human-readable form of the type at an index in the specified dex file.
// Example outputs: char[], java.lang.String.
std::string PrettyType(uint32_t type_idx, const DexFile& dex_file);
// Returns a human-readable form of the name of the given class.
// Given String.class, the output would be "java.lang.Class<java.lang.String>".
std::string PrettyClass(mirror::Class* c)
// Returns a human-readable form of the name of the given class with its class loader.
std::string PrettyClassAndClassLoader(mirror::Class* c)
// Returns a human-readable version of the Java part of the access flags, e.g., "private static "
// (note the trailing whitespace).
std::string PrettyJavaAccessFlags(uint32_t access_flags);
// Returns a human-readable size string such as "1MB".
std::string PrettySize(int64_t size_in_bytes);
// Performs JNI name mangling as described in section 11.3 "Linking Native Methods"
// of the JNI spec.
std::string MangleForJni(const std::string& s);
// Turn "java.lang.String" into "Ljava/lang/String;".
std::string DotToDescriptor(const char* class_name);
// Turn "Ljava/lang/String;" into "java.lang.String" using the conventions of
// java.lang.Class.getName().
std::string DescriptorToDot(const char* descriptor);
// Turn "Ljava/lang/String;" into "java/lang/String" using the opposite conventions of
// java.lang.Class.getName().
std::string DescriptorToName(const char* descriptor);
// Tests for whether 's' is a valid class name in the three common forms:
bool IsValidBinaryClassName(const char* s); // "java.lang.String"
bool IsValidJniClassName(const char* s); // "java/lang/String"
bool IsValidDescriptor(const char* s); // "Ljava/lang/String;"
// Returns whether the given string is a valid field or method name,
// additionally allowing names that begin with '<' and end with '>'.
bool IsValidMemberName(const char* s);
// Returns the JNI native function name for the non-overloaded method 'm'.
std::string JniShortName(ArtMethod* m)
// Returns the JNI native function name for the overloaded method 'm'.
std::string JniLongName(ArtMethod* m)
bool ReadFileToString(const std::string& file_name, std::string* result);
bool PrintFileToLog(const std::string& file_name, LogSeverity level);
// Splits a string using the given separator character into a vector of
// strings. Empty strings will be omitted.
void Split(const std::string& s, char separator, std::vector<std::string>* result);
// Trims whitespace off both ends of the given string.
std::string Trim(const std::string& s);
// Joins a vector of strings into a single string, using the given separator.
template <typename StringT> std::string Join(const std::vector<StringT>& strings, char separator);
// Returns the calling thread's tid. (The C libraries don't expose this.)
pid_t GetTid();
// Returns the given thread's name.
std::string GetThreadName(pid_t tid);
// Returns details of the given thread's stack.
void GetThreadStack(pthread_t thread, void** stack_base, size_t* stack_size, size_t* guard_size);
// Reads data from "/proc/self/task/${tid}/stat".
void GetTaskStats(pid_t tid, char* state, int* utime, int* stime, int* task_cpu);
// Returns the name of the scheduler group for the given thread the current process, or the empty string.
std::string GetSchedulerGroupName(pid_t tid);
// Sets the name of the current thread. The name may be truncated to an
// implementation-defined limit.
void SetThreadName(const char* thread_name);
// Dumps the native stack for thread 'tid' to 'os'.
void DumpNativeStack(std::ostream& os,
pid_t tid,
BacktraceMap* map = nullptr,
const char* prefix = "",
ArtMethod* current_method = nullptr,
void* ucontext = nullptr)
// Dumps the kernel stack for thread 'tid' to 'os'. Note that this is only available on linux-x86.
void DumpKernelStack(std::ostream& os,
pid_t tid,
const char* prefix = "",
bool include_count = true);
// Find $ANDROID_ROOT, /system, or abort.
const char* GetAndroidRoot();
// Find $ANDROID_DATA, /data, or abort.
const char* GetAndroidData();
// Find $ANDROID_DATA, /data, or return null.
const char* GetAndroidDataSafe(std::string* error_msg);
// Returns the dalvik-cache location, with subdir appended. Returns the empty string if the cache
// could not be found (or created).
std::string GetDalvikCache(const char* subdir, bool create_if_absent = true);
// Returns the dalvik-cache location, or dies trying. subdir will be
// appended to the cache location.
std::string GetDalvikCacheOrDie(const char* subdir, bool create_if_absent = true);
// Return true if we found the dalvik cache and stored it in the dalvik_cache argument.
// have_android_data will be set to true if we have an ANDROID_DATA that exists,
// dalvik_cache_exists will be true if there is a dalvik-cache directory that is present.
// The flag is_global_cache tells whether this cache is /data/dalvik-cache.
void GetDalvikCache(const char* subdir, bool create_if_absent, std::string* dalvik_cache,
bool* have_android_data, bool* dalvik_cache_exists, bool* is_global_cache);
// Returns the absolute dalvik-cache path for a DexFile or OatFile. The path returned will be
// rooted at cache_location.
bool GetDalvikCacheFilename(const char* file_location, const char* cache_location,
std::string* filename, std::string* error_msg);
// Returns the absolute dalvik-cache path for a DexFile or OatFile, or
// dies trying. The path returned will be rooted at cache_location.
std::string GetDalvikCacheFilenameOrDie(const char* file_location,
const char* cache_location);
// Returns the system location for an image
std::string GetSystemImageFilename(const char* location, InstructionSet isa);
// Wrapper on fork/execv to run a command in a subprocess.
bool Exec(std::vector<std::string>& arg_vector, std::string* error_msg);
int ExecAndReturnCode(std::vector<std::string>& arg_vector, std::string* error_msg);
// Returns true if the file exists.
bool FileExists(const std::string& filename);
bool FileExistsAndNotEmpty(const std::string& filename);
class VoidFunctor {
template <typename A>
inline void operator() (A a ATTRIBUTE_UNUSED) const {
template <typename A, typename B>
inline void operator() (A a ATTRIBUTE_UNUSED, B b ATTRIBUTE_UNUSED) const {
template <typename A, typename B, typename C>
inline void operator() (A a ATTRIBUTE_UNUSED, B b ATTRIBUTE_UNUSED, C c ATTRIBUTE_UNUSED) const {
template <typename Vector>
void Push32(Vector* buf, int32_t data) {
static_assert(std::is_same<typename Vector::value_type, uint8_t>::value, "Invalid value type");
buf->push_back(data & 0xff);
buf->push_back((data >> 8) & 0xff);
buf->push_back((data >> 16) & 0xff);
buf->push_back((data >> 24) & 0xff);
inline bool TestBitmap(size_t idx, const uint8_t* bitmap) {
return ((bitmap[idx / kBitsPerByte] >> (idx % kBitsPerByte)) & 0x01) != 0;
static inline constexpr bool ValidPointerSize(size_t pointer_size) {
return pointer_size == 4 || pointer_size == 8;
void DumpMethodCFG(ArtMethod* method, std::ostream& os) SHARED_REQUIRES(Locks::mutator_lock_);
void DumpMethodCFG(const DexFile* dex_file, uint32_t dex_method_idx, std::ostream& os);
static inline const void* EntryPointToCodePointer(const void* entry_point) {
uintptr_t code = reinterpret_cast<uintptr_t>(entry_point);
// TODO: Make this Thumb2 specific. It is benign on other architectures as code is always at
// least 2 byte aligned.
code &= ~0x1;
return reinterpret_cast<const void*>(code);
using UsageFn = void (*)(const char*, ...);
template <typename T>
static void ParseUintOption(const StringPiece& option,
const std::string& option_name,
T* out,
UsageFn Usage,
bool is_long_option = true) {
std::string option_prefix = option_name + (is_long_option ? "=" : "");
DCHECK(option.starts_with(option_prefix)) << option << " " << option_prefix;
const char* value_string = option.substr(option_prefix.size()).data();
int64_t parsed_integer_value = 0;
if (!ParseInt(value_string, &parsed_integer_value)) {
Usage("Failed to parse %s '%s' as an integer", option_name.c_str(), value_string);
if (parsed_integer_value < 0) {
Usage("%s passed a negative value %d", option_name.c_str(), parsed_integer_value);
*out = dchecked_integral_cast<T>(parsed_integer_value);
void ParseDouble(const std::string& option,
char after_char,
double min,
double max,
double* parsed_value,
UsageFn Usage);
#if defined(__BIONIC__)
struct Arc4RandomGenerator {
typedef uint32_t result_type;
static constexpr uint32_t min() { return std::numeric_limits<uint32_t>::min(); }
static constexpr uint32_t max() { return std::numeric_limits<uint32_t>::max(); }
uint32_t operator() () { return arc4random(); }
using RNG = Arc4RandomGenerator;
using RNG = std::random_device;
template <typename T>
T GetRandomNumber(T min, T max) {
CHECK_LT(min, max);
std::uniform_int_distribution<T> dist(min, max);
RNG rng;
return dist(rng);
// Return the file size in bytes or -1 if the file does not exists.
int64_t GetFileSizeBytes(const std::string& filename);
// Sleep forever and never come back.
NO_RETURN void SleepForever();
inline void FlushInstructionCache(char* begin, char* end) {
// Only use __builtin___clear_cache with Clang or with GCC >= 4.3.0
// (__builtin___clear_cache was introduced in GCC 4.3.0).
#if defined(__clang__) || GCC_VERSION >= 40300
__builtin___clear_cache(begin, end);
// Only warn on non-Intel platforms, as x86 and x86-64 do not need
// cache flush instructions, as long as the "code uses the same
// linear address for modifying and fetching the instruction". See
// "Intel(R) 64 and IA-32 Architectures Software Developer's Manual
// Volume 3A: System Programming Guide, Part 1", section 11.6
// "Self-Modifying Code".
#if !defined(__i386__) && !defined(__x86_64__)
UNIMPLEMENTED(WARNING) << "cache flush";
} // namespace art