https://github.com/halide/Halide
Tip revision: bf3b66f9d5ce84bd85f0390c9e198b2e8f7bd554 authored by Z Stern on 24 September 2020, 18:00:10 UTC
Add atomic update support to thread_pool_common parallel for implementations.
Add atomic update support to thread_pool_common parallel for implementations.
Tip revision: bf3b66f
Util.h
// Always use assert, even if llvm-config defines NDEBUG
#ifdef NDEBUG
#undef NDEBUG
#include <assert.h>
#define NDEBUG
#else
#include <assert.h>
#endif
#ifndef HALIDE_UTIL_H
#define HALIDE_UTIL_H
/** \file
* Various utility functions used internally Halide. */
#include <cstdint>
#include <cstring>
#include <limits>
#include <string>
#include <utility>
#include <vector>
#include "runtime/HalideRuntime.h"
#ifdef Halide_STATIC_DEFINE
#define HALIDE_EXPORT
#else
#if defined(_MSC_VER)
// Halide_EXPORTS is quietly defined by CMake when building a shared library
#ifdef Halide_EXPORTS
#define HALIDE_EXPORT __declspec(dllexport)
#else
#define HALIDE_EXPORT __declspec(dllimport)
#endif
#else
#define HALIDE_EXPORT __attribute__((visibility("default")))
#endif
#endif
// If we're in user code, we don't want certain functions to be inlined.
#if defined(COMPILING_HALIDE) || defined(BUILDING_PYTHON)
#define HALIDE_NO_USER_CODE_INLINE
#else
#define HALIDE_NO_USER_CODE_INLINE HALIDE_NEVER_INLINE
#endif
// On windows, Halide needs a larger stack than the default MSVC provides
#ifdef _MSC_VER
#pragma comment(linker, "/STACK:8388608,1048576")
#endif
namespace Halide {
/** Load a plugin in the form of a dynamic library (e.g. for custom autoschedulers).
* If the string doesn't contain any . characters, the proper prefix and/or suffix
* for the platform will be added:
*
* foo -> libfoo.so (Linux/OSX/etc -- note that .dylib is not supported)
* foo -> foo.dll (Windows)
*
* otherwise, it is assumed to be an appropriate pathname.
*
* Any error in loading will assert-fail. */
void load_plugin(const std::string &lib_name);
namespace Internal {
/** Some numeric conversions are UB if the value won't fit in the result;
* safe_numeric_cast<>() is meant as a drop-in replacement for a C/C++ cast
* that adds well-defined behavior for the UB cases, attempting to mimic
* common implementation behavior as much as possible.
*/
template<typename DST, typename SRC,
typename std::enable_if<std::is_floating_point<SRC>::value>::type * = nullptr>
DST safe_numeric_cast(SRC s) {
if (std::is_integral<DST>::value) {
// Treat float -> int as a saturating cast; this is handled
// in different ways by different compilers, so an arbitrary but safe
// choice like this is reasonable.
if (s < (SRC)std::numeric_limits<DST>::min()) {
return std::numeric_limits<DST>::min();
}
if (s > (SRC)std::numeric_limits<DST>::max()) {
return std::numeric_limits<DST>::max();
}
}
return (DST)s;
}
template<typename DST, typename SRC,
typename std::enable_if<std::is_integral<SRC>::value>::type * = nullptr>
DST safe_numeric_cast(SRC s) {
if (std::is_integral<DST>::value) {
// any-int -> signed-int is technically UB if value won't fit;
// in practice, common compilers implement such conversions as done below
// (as verified by exhaustive testing on Clang for x86-64). We could
// probably continue to rely on that behavior, but making it explicit
// avoids possible wrather of UBSan and similar debug helpers.
// (Yes, using sizeof for this comparison is a little odd for the uint->int
// case, but the intent is to match existing common behavior, which this does.)
if (std::is_integral<SRC>::value && std::is_signed<DST>::value && sizeof(DST) < sizeof(SRC)) {
using UnsignedSrc = typename std::make_unsigned<SRC>::type;
return (DST)(s & (UnsignedSrc)(-1));
}
}
return (DST)s;
}
/** An aggressive form of reinterpret cast used for correct type-punning. */
template<typename DstType, typename SrcType>
DstType reinterpret_bits(const SrcType &src) {
static_assert(sizeof(SrcType) == sizeof(DstType), "Types must be same size");
DstType dst;
memcpy(&dst, &src, sizeof(SrcType));
return dst;
}
/** Make a unique name for an object based on the name of the stack
* variable passed in. If introspection isn't working or there are no
* debug symbols, just uses unique_name with the given prefix. */
std::string make_entity_name(void *stack_ptr, const std::string &type, char prefix);
/** Get value of an environment variable. Returns its value
* is defined in the environment. If the var is not defined, an empty string
* is returned.
*/
std::string get_env_variable(char const *env_var_name);
/** Get the name of the currently running executable. Platform-specific.
* If program name cannot be retrieved, function returns an empty string. */
std::string running_program_name();
/** Generate a unique name starting with the given prefix. It's unique
* relative to all other strings returned by unique_name in this
* process.
*
* The single-character version always appends a numeric suffix to the
* character.
*
* The string version will either return the input as-is (with high
* probability on the first time it is called with that input), or
* replace any existing '$' characters with underscores, then add a
* '$' sign and a numeric suffix to it.
*
* Note that unique_name('f') therefore differs from
* unique_name("f"). The former returns something like f123, and the
* latter returns either f or f$123.
*/
// @{
std::string unique_name(char prefix);
std::string unique_name(const std::string &prefix);
// @}
/** Test if the first string starts with the second string */
bool starts_with(const std::string &str, const std::string &prefix);
/** Test if the first string ends with the second string */
bool ends_with(const std::string &str, const std::string &suffix);
/** Replace all matches of the second string in the first string with the last string */
std::string replace_all(const std::string &str, const std::string &find, const std::string &replace);
/** Split the source string using 'delim' as the divider. */
std::vector<std::string> split_string(const std::string &source, const std::string &delim);
/** Perform a left fold of a vector. Returns a default-constructed
* vector element if the vector is empty. Similar to std::accumulate
* but with a less clunky syntax. */
template<typename T, typename Fn>
T fold_left(const std::vector<T> &vec, Fn f) {
T result;
if (vec.empty()) {
return result;
}
result = vec[0];
for (size_t i = 1; i < vec.size(); i++) {
result = f(result, vec[i]);
}
return result;
}
/** Returns a right fold of a vector. Returns a default-constructed
* vector element if the vector is empty. */
template<typename T, typename Fn>
T fold_right(const std::vector<T> &vec, Fn f) {
T result;
if (vec.empty()) {
return result;
}
result = vec.back();
for (size_t i = vec.size() - 1; i > 0; i--) {
result = f(vec[i - 1], result);
}
return result;
}
template<typename... T>
struct meta_and : std::true_type {};
template<typename T1, typename... Args>
struct meta_and<T1, Args...> : std::integral_constant<bool, T1::value && meta_and<Args...>::value> {};
template<typename... T>
struct meta_or : std::false_type {};
template<typename T1, typename... Args>
struct meta_or<T1, Args...> : std::integral_constant<bool, T1::value || meta_or<Args...>::value> {};
template<typename To, typename... Args>
struct all_are_convertible : meta_and<std::is_convertible<Args, To>...> {};
/** Returns base name and fills in namespaces, outermost one first in vector. */
std::string extract_namespaces(const std::string &name, std::vector<std::string> &namespaces);
struct FileStat {
uint64_t file_size;
uint32_t mod_time; // Unix epoch time
uint32_t uid;
uint32_t gid;
uint32_t mode;
};
/** Create a unique file with a name of the form prefixXXXXXsuffix in an arbitrary
* (but writable) directory; this is typically /tmp, but the specific
* location is not guaranteed. (Note that the exact form of the file name
* may vary; in particular, the suffix may be ignored on Windows.)
* The file is created (but not opened), thus this can be called from
* different threads (or processes, e.g. when building with parallel make)
* without risking collision. Note that if this file is used as a temporary
* file, the caller is responsibly for deleting it. Neither the prefix nor suffix
* may contain a directory separator.
*/
std::string file_make_temp(const std::string &prefix, const std::string &suffix);
/** Create a unique directory in an arbitrary (but writable) directory; this is
* typically somewhere inside /tmp, but the specific location is not guaranteed.
* The directory will be empty (i.e., this will never return /tmp itself,
* but rather a new directory inside /tmp). The caller is responsible for removing the
* directory after use.
*/
std::string dir_make_temp();
/** Wrapper for access(). Quietly ignores errors. */
bool file_exists(const std::string &name);
/** assert-fail if the file doesn't exist. useful primarily for testing purposes. */
void assert_file_exists(const std::string &name);
/** assert-fail if the file DOES exist. useful primarily for testing purposes. */
void assert_no_file_exists(const std::string &name);
/** Wrapper for unlink(). Asserts upon error. */
void file_unlink(const std::string &name);
/** Wrapper for unlink(). Quietly ignores errors. */
void file_unlink(const std::string &name);
/** Ensure that no file with this path exists. If such a file
* exists and cannot be removed, assert-fail. */
void ensure_no_file_exists(const std::string &name);
/** Wrapper for rmdir(). Asserts upon error. */
void dir_rmdir(const std::string &name);
/** Wrapper for stat(). Asserts upon error. */
FileStat file_stat(const std::string &name);
/** Read the entire contents of a file into a vector<char>. The file
* is read in binary mode. Errors trigger an assertion failure. */
std::vector<char> read_entire_file(const std::string &pathname);
/** Create or replace the contents of a file with a given pointer-and-length
* of memory. If the file doesn't exist, it is created; if it does exist, it
* is completely overwritten. Any error triggers an assertion failure. */
void write_entire_file(const std::string &pathname, const void *source, size_t source_len);
inline void write_entire_file(const std::string &pathname, const std::vector<char> &source) {
write_entire_file(pathname, source.data(), source.size());
}
/** A simple utility class that creates a temporary file in its ctor and
* deletes that file in its dtor; this is useful for temporary files that you
* want to ensure are deleted when exiting a certain scope. Since this is essentially
* just an RAII wrapper around file_make_temp() and file_unlink(), it has the same
* failure modes (i.e.: assertion upon error).
*/
class TemporaryFile final {
public:
TemporaryFile(const std::string &prefix, const std::string &suffix)
: temp_path(file_make_temp(prefix, suffix)), do_unlink(true) {
}
const std::string &pathname() const {
return temp_path;
}
~TemporaryFile() {
if (do_unlink) {
file_unlink(temp_path);
}
}
// You can call this if you want to defeat the automatic deletion;
// this is rarely what you want to do (since it defeats the purpose
// of this class), but can be quite handy for debugging purposes.
void detach() {
do_unlink = false;
}
private:
const std::string temp_path;
bool do_unlink;
TemporaryFile(const TemporaryFile &) = delete;
void operator=(const TemporaryFile &) = delete;
};
/** Routines to test if math would overflow for signed integers with
* the given number of bits. */
// @{
bool add_would_overflow(int bits, int64_t a, int64_t b);
bool sub_would_overflow(int bits, int64_t a, int64_t b);
bool mul_would_overflow(int bits, int64_t a, int64_t b);
// @}
/** Helper class for saving/restoring variable values on the stack, to allow
* for early-exit that preserves correctness */
template<typename T>
struct ScopedValue {
T &var;
T old_value;
/** Preserve the old value, restored at dtor time */
ScopedValue(T &var)
: var(var), old_value(var) {
}
/** Preserve the old value, then set the var to a new value. */
ScopedValue(T &var, T new_value)
: var(var), old_value(var) {
var = new_value;
}
~ScopedValue() {
var = old_value;
}
operator T() const {
return old_value;
}
// allow move but not copy
ScopedValue(const ScopedValue &that) = delete;
ScopedValue(ScopedValue &&that) noexcept = default;
};
// Wrappers for some C++14-isms that are useful and trivially implementable
// in C++11; these are defined in the Halide::Internal namespace. If we
// are compiling under C++14 or later, we just use the standard implementations
// rather than our own.
#if __cplusplus >= 201402L
// C++14: Use the standard implementations
using std::index_sequence;
using std::integer_sequence;
using std::make_index_sequence;
using std::make_integer_sequence;
#else
// C++11: std::integer_sequence (etc) is standard in C++14 but not C++11, but
// is easily written in C++11. This is a simple version that could
// probably be improved.
template<typename T, T... Ints>
struct integer_sequence {
static constexpr size_t size() {
return sizeof...(Ints);
}
};
template<typename T>
struct next_integer_sequence;
template<typename T, T... Ints>
struct next_integer_sequence<integer_sequence<T, Ints...>> {
using type = integer_sequence<T, Ints..., sizeof...(Ints)>;
};
template<typename T, T I, T N>
struct make_integer_sequence_helper {
using type = typename next_integer_sequence<
typename make_integer_sequence_helper<T, I + 1, N>::type>::type;
};
template<typename T, T N>
struct make_integer_sequence_helper<T, N, N> {
using type = integer_sequence<T>;
};
template<typename T, T N>
using make_integer_sequence = typename make_integer_sequence_helper<T, 0, N>::type;
template<size_t... Ints>
using index_sequence = integer_sequence<size_t, Ints...>;
template<size_t N>
using make_index_sequence = make_integer_sequence<size_t, N>;
#endif
// Helpers for timing blocks of code. Put 'TIC;' at the start and
// 'TOC;' at the end. Timing is reported at the toc via
// debug(0). The calls can be nested and will pretty-print
// appropriately. Took this idea from matlab via Jon Barron.
//
// Note that this uses global state internally, and is not thread-safe
// at all. Only use it for single-threaded debugging sessions.
void halide_tic_impl(const char *file, int line);
void halide_toc_impl(const char *file, int line);
#define HALIDE_TIC Halide::Internal::halide_tic_impl(__FILE__, __LINE__)
#define HALIDE_TOC Halide::Internal::halide_toc_impl(__FILE__, __LINE__)
#ifdef COMPILING_HALIDE
#define TIC HALIDE_TIC
#define TOC HALIDE_TOC
#endif
// statically cast a value from one type to another: this is really just
// some syntactic sugar around static_cast<>() to avoid compiler warnings
// regarding 'bool' in some compliation configurations.
template<typename TO>
struct StaticCast {
template<typename FROM, typename TO2 = TO, typename std::enable_if<!std::is_same<TO2, bool>::value>::type * = nullptr>
inline constexpr static TO2 value(const FROM &from) {
return static_cast<TO2>(from);
}
template<typename FROM, typename TO2 = TO, typename std::enable_if<std::is_same<TO2, bool>::value>::type * = nullptr>
inline constexpr static TO2 value(const FROM &from) {
return from != 0;
}
};
// Like std::is_convertible, but with additional tests for arithmetic types:
// ensure that the value will roundtrip losslessly (e.g., no integer truncation
// or dropping of fractional parts).
template<typename TO>
struct IsRoundtrippable {
template<typename FROM, typename TO2 = TO, typename std::enable_if<!std::is_convertible<FROM, TO>::value>::type * = nullptr>
inline constexpr static bool value(const FROM &from) {
return false;
}
template<typename FROM, typename TO2 = TO, typename std::enable_if<std::is_convertible<FROM, TO>::value && std::is_arithmetic<TO>::value && std::is_arithmetic<FROM>::value && !std::is_same<TO, FROM>::value>::type * = nullptr>
inline constexpr static bool value(const FROM &from) {
return StaticCast<FROM>::value(StaticCast<TO>::value(from)) == from;
}
template<typename FROM, typename TO2 = TO, typename std::enable_if<std::is_convertible<FROM, TO>::value && !(std::is_arithmetic<TO>::value && std::is_arithmetic<FROM>::value && !std::is_same<TO, FROM>::value)>::type * = nullptr>
inline constexpr static bool value(const FROM &from) {
return true;
}
};
/** Emit a version of a string that is a valid identifier in C (. is replaced with _) */
std::string c_print_name(const std::string &name);
/** Return the LLVM_VERSION against which this libHalide is compiled. This is provided
* only for internal tests which need to verify behavior; please don't use this outside
* of Halide tests. */
int get_llvm_version();
} // namespace Internal
} // namespace Halide
#endif