Halide 16.0.0
Halide compiler and libraries
Util.h
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1// Always use assert, even if llvm-config defines NDEBUG
2#ifdef NDEBUG
3#undef NDEBUG
4#include <assert.h>
5#define NDEBUG
6#else
7#include <cassert>
8#endif
9
10#ifndef HALIDE_UTIL_H
11#define HALIDE_UTIL_H
12
13/** \file
14 * Various utility functions used internally Halide. */
15
16#include <cstdint>
17#include <cstring>
18#include <functional>
19#include <limits>
20#include <string>
21#include <utility>
22#include <vector>
23
25
26#ifdef Halide_STATIC_DEFINE
27#define HALIDE_EXPORT
28#else
29#if defined(_MSC_VER)
30// Halide_EXPORTS is quietly defined by CMake when building a shared library
31#ifdef Halide_EXPORTS
32#define HALIDE_EXPORT __declspec(dllexport)
33#else
34#define HALIDE_EXPORT __declspec(dllimport)
35#endif
36#else
37#define HALIDE_EXPORT __attribute__((visibility("default")))
38#endif
39#endif
40
41// If we're in user code, we don't want certain functions to be inlined.
42#if defined(COMPILING_HALIDE) || defined(BUILDING_PYTHON)
43#define HALIDE_NO_USER_CODE_INLINE
44#else
45#define HALIDE_NO_USER_CODE_INLINE HALIDE_NEVER_INLINE
46#endif
47
48// Clang uses __has_feature() for sanitizers...
49#if defined(__has_feature)
50#if __has_feature(address_sanitizer)
51#define HALIDE_INTERNAL_USING_ASAN
52#endif
53#if __has_feature(memory_sanitizer)
54#define HALIDE_INTERNAL_USING_MSAN
55#endif
56#if __has_feature(thread_sanitizer)
57#define HALIDE_INTERNAL_USING_TSAN
58#endif
59#if __has_feature(coverage_sanitizer)
60#define HALIDE_INTERNAL_USING_COVSAN
61#endif
62#if __has_feature(undefined_behavior_sanitizer)
63#define HALIDE_INTERNAL_USING_UBSAN
64#endif
65#endif
66
67// ...but GCC/MSVC don't like __has_feature, so handle them separately.
68// (Only AddressSanitizer for now, not sure if any others are well-supported
69// outside of Clang.
70#if defined(__SANITIZE_ADDRESS__) && !defined(HALIDE_INTERNAL_USING_ASAN)
71#define HALIDE_INTERNAL_USING_ASAN
72#endif
73
74namespace Halide {
75
76/** Load a plugin in the form of a dynamic library (e.g. for custom autoschedulers).
77 * If the string doesn't contain any . characters, the proper prefix and/or suffix
78 * for the platform will be added:
79 *
80 * foo -> libfoo.so (Linux/OSX/etc -- note that .dylib is not supported)
81 * foo -> foo.dll (Windows)
82 *
83 * otherwise, it is assumed to be an appropriate pathname.
84 *
85 * Any error in loading will assert-fail. */
86void load_plugin(const std::string &lib_name);
87
88namespace Internal {
89
90/** Some numeric conversions are UB if the value won't fit in the result;
91 * safe_numeric_cast<>() is meant as a drop-in replacement for a C/C++ cast
92 * that adds well-defined behavior for the UB cases, attempting to mimic
93 * common implementation behavior as much as possible.
94 */
95template<typename DST, typename SRC,
96 typename std::enable_if<std::is_floating_point<SRC>::value>::type * = nullptr>
98 if (std::is_integral<DST>::value) {
99 // Treat float -> int as a saturating cast; this is handled
100 // in different ways by different compilers, so an arbitrary but safe
101 // choice like this is reasonable.
102 if (s < (SRC)std::numeric_limits<DST>::min()) {
104 }
105 if (s > (SRC)std::numeric_limits<DST>::max()) {
107 }
108 }
109 return (DST)s;
110}
111
112template<typename DST, typename SRC,
113 typename std::enable_if<std::is_integral<SRC>::value>::type * = nullptr>
114DST safe_numeric_cast(SRC s) {
115 if (std::is_integral<DST>::value) {
116 // any-int -> signed-int is technically UB if value won't fit;
117 // in practice, common compilers implement such conversions as done below
118 // (as verified by exhaustive testing on Clang for x86-64). We could
119 // probably continue to rely on that behavior, but making it explicit
120 // avoids possible wrather of UBSan and similar debug helpers.
121 // (Yes, using sizeof for this comparison is a little odd for the uint->int
122 // case, but the intent is to match existing common behavior, which this does.)
123 if (std::is_integral<SRC>::value && std::is_signed<DST>::value && sizeof(DST) < sizeof(SRC)) {
124 using UnsignedSrc = typename std::make_unsigned<SRC>::type;
125 return (DST)(s & (UnsignedSrc)(-1));
126 }
127 }
128 return (DST)s;
129}
130
131/** An aggressive form of reinterpret cast used for correct type-punning. */
132template<typename DstType, typename SrcType>
133DstType reinterpret_bits(const SrcType &src) {
134 static_assert(sizeof(SrcType) == sizeof(DstType), "Types must be same size");
135 DstType dst;
136 memcpy(&dst, &src, sizeof(SrcType));
137 return dst;
138}
139
140/** Make a unique name for an object based on the name of the stack
141 * variable passed in. If introspection isn't working or there are no
142 * debug symbols, just uses unique_name with the given prefix. */
143std::string make_entity_name(void *stack_ptr, const std::string &type, char prefix);
144
145/** Get value of an environment variable. Returns its value
146 * is defined in the environment. If the var is not defined, an empty string
147 * is returned.
148 */
149std::string get_env_variable(char const *env_var_name);
150
151/** Get the name of the currently running executable. Platform-specific.
152 * If program name cannot be retrieved, function returns an empty string. */
154
155/** Generate a unique name starting with the given prefix. It's unique
156 * relative to all other strings returned by unique_name in this
157 * process.
158 *
159 * The single-character version always appends a numeric suffix to the
160 * character.
161 *
162 * The string version will either return the input as-is (with high
163 * probability on the first time it is called with that input), or
164 * replace any existing '$' characters with underscores, then add a
165 * '$' sign and a numeric suffix to it.
166 *
167 * Note that unique_name('f') therefore differs from
168 * unique_name("f"). The former returns something like f123, and the
169 * latter returns either f or f$123.
170 */
171// @{
172std::string unique_name(char prefix);
173std::string unique_name(const std::string &prefix);
174// @}
175
176/** Test if the first string starts with the second string */
177bool starts_with(const std::string &str, const std::string &prefix);
178
179/** Test if the first string ends with the second string */
180bool ends_with(const std::string &str, const std::string &suffix);
181
182/** Replace all matches of the second string in the first string with the last string */
183std::string replace_all(const std::string &str, const std::string &find, const std::string &replace);
184
185/** Split the source string using 'delim' as the divider. */
186std::vector<std::string> split_string(const std::string &source, const std::string &delim);
187
188/** Perform a left fold of a vector. Returns a default-constructed
189 * vector element if the vector is empty. Similar to std::accumulate
190 * but with a less clunky syntax. */
191template<typename T, typename Fn>
192T fold_left(const std::vector<T> &vec, Fn f) {
193 T result;
194 if (vec.empty()) {
195 return result;
196 }
197 result = vec[0];
198 for (size_t i = 1; i < vec.size(); i++) {
199 result = f(result, vec[i]);
200 }
201 return result;
202}
203
204/** Returns a right fold of a vector. Returns a default-constructed
205 * vector element if the vector is empty. */
206template<typename T, typename Fn>
207T fold_right(const std::vector<T> &vec, Fn f) {
208 T result;
209 if (vec.empty()) {
210 return result;
211 }
212 result = vec.back();
213 for (size_t i = vec.size() - 1; i > 0; i--) {
214 result = f(vec[i - 1], result);
215 }
216 return result;
217}
218
219template<typename... T>
220struct meta_and : std::true_type {};
221
222template<typename T1, typename... Args>
223struct meta_and<T1, Args...> : std::integral_constant<bool, T1::value && meta_and<Args...>::value> {};
224
225template<typename... T>
226struct meta_or : std::false_type {};
227
228template<typename T1, typename... Args>
229struct meta_or<T1, Args...> : std::integral_constant<bool, T1::value || meta_or<Args...>::value> {};
230
231template<typename To, typename... Args>
232struct all_are_convertible : meta_and<std::is_convertible<Args, To>...> {};
233
234/** Returns base name and fills in namespaces, outermost one first in vector. */
235std::string extract_namespaces(const std::string &name, std::vector<std::string> &namespaces);
236
237/** Like extract_namespaces(), but strip and discard the namespaces, returning base name only */
238std::string strip_namespaces(const std::string &name);
239
240struct FileStat {
242 uint32_t mod_time; // Unix epoch time
246};
247
248/** Create a unique file with a name of the form prefixXXXXXsuffix in an arbitrary
249 * (but writable) directory; this is typically /tmp, but the specific
250 * location is not guaranteed. (Note that the exact form of the file name
251 * may vary; in particular, the suffix may be ignored on Windows.)
252 * The file is created (but not opened), thus this can be called from
253 * different threads (or processes, e.g. when building with parallel make)
254 * without risking collision. Note that if this file is used as a temporary
255 * file, the caller is responsibly for deleting it. Neither the prefix nor suffix
256 * may contain a directory separator.
257 */
258std::string file_make_temp(const std::string &prefix, const std::string &suffix);
259
260/** Create a unique directory in an arbitrary (but writable) directory; this is
261 * typically somewhere inside /tmp, but the specific location is not guaranteed.
262 * The directory will be empty (i.e., this will never return /tmp itself,
263 * but rather a new directory inside /tmp). The caller is responsible for removing the
264 * directory after use.
265 */
266std::string dir_make_temp();
267
268/** Wrapper for access(). Quietly ignores errors. */
269bool file_exists(const std::string &name);
270
271/** assert-fail if the file doesn't exist. useful primarily for testing purposes. */
272void assert_file_exists(const std::string &name);
273
274/** assert-fail if the file DOES exist. useful primarily for testing purposes. */
275void assert_no_file_exists(const std::string &name);
276
277/** Wrapper for unlink(). Asserts upon error. */
278void file_unlink(const std::string &name);
279
280/** Wrapper for unlink(). Quietly ignores errors. */
281void file_unlink(const std::string &name);
282
283/** Ensure that no file with this path exists. If such a file
284 * exists and cannot be removed, assert-fail. */
285void ensure_no_file_exists(const std::string &name);
286
287/** Wrapper for rmdir(). Asserts upon error. */
288void dir_rmdir(const std::string &name);
289
290/** Wrapper for stat(). Asserts upon error. */
291FileStat file_stat(const std::string &name);
292
293/** Read the entire contents of a file into a vector<char>. The file
294 * is read in binary mode. Errors trigger an assertion failure. */
295std::vector<char> read_entire_file(const std::string &pathname);
296
297/** Create or replace the contents of a file with a given pointer-and-length
298 * of memory. If the file doesn't exist, it is created; if it does exist, it
299 * is completely overwritten. Any error triggers an assertion failure. */
300void write_entire_file(const std::string &pathname, const void *source, size_t source_len);
301
302inline void write_entire_file(const std::string &pathname, const std::vector<char> &source) {
303 write_entire_file(pathname, source.data(), source.size());
304}
305
306/** A simple utility class that creates a temporary file in its ctor and
307 * deletes that file in its dtor; this is useful for temporary files that you
308 * want to ensure are deleted when exiting a certain scope. Since this is essentially
309 * just an RAII wrapper around file_make_temp() and file_unlink(), it has the same
310 * failure modes (i.e.: assertion upon error).
311 */
312class TemporaryFile final {
313public:
314 TemporaryFile(const std::string &prefix, const std::string &suffix)
315 : temp_path(file_make_temp(prefix, suffix)) {
316 }
317 const std::string &pathname() const {
318 return temp_path;
319 }
321 if (do_unlink) {
322 file_unlink(temp_path);
323 }
324 }
325 // You can call this if you want to defeat the automatic deletion;
326 // this is rarely what you want to do (since it defeats the purpose
327 // of this class), but can be quite handy for debugging purposes.
328 void detach() {
329 do_unlink = false;
330 }
331
332private:
333 const std::string temp_path;
334 bool do_unlink = true;
335
336public:
337 TemporaryFile(const TemporaryFile &) = delete;
341};
342
343/** Routines to test if math would overflow for signed integers with
344 * the given number of bits. */
345// @{
346bool add_would_overflow(int bits, int64_t a, int64_t b);
347bool sub_would_overflow(int bits, int64_t a, int64_t b);
348bool mul_would_overflow(int bits, int64_t a, int64_t b);
349// @}
350
351/** Routines to perform arithmetic on signed types without triggering signed
352 * overflow. If overflow would occur, sets result to zero, and returns
353 * false. Otherwise set result to the correct value, and returns true. */
354// @{
358// @}
359
360/** Helper class for saving/restoring variable values on the stack, to allow
361 * for early-exit that preserves correctness */
362template<typename T>
364 T &var;
366 /** Preserve the old value, restored at dtor time */
368 : var(var), old_value(var) {
369 }
370 /** Preserve the old value, then set the var to a new value. */
371 ScopedValue(T &var, T new_value)
372 : var(var), old_value(var) {
373 var = new_value;
374 }
376 var = old_value;
377 }
378 operator T() const {
379 return old_value;
380 }
381 // allow move but not copy
382 ScopedValue(const ScopedValue &that) = delete;
383 ScopedValue(ScopedValue &&that) noexcept = default;
384};
385
386// Helpers for timing blocks of code. Put 'TIC;' at the start and
387// 'TOC;' at the end. Timing is reported at the toc via
388// debug(0). The calls can be nested and will pretty-print
389// appropriately. Took this idea from matlab via Jon Barron.
390//
391// Note that this uses global state internally, and is not thread-safe
392// at all. Only use it for single-threaded debugging sessions.
393
394void halide_tic_impl(const char *file, int line);
395void halide_toc_impl(const char *file, int line);
396#define HALIDE_TIC Halide::Internal::halide_tic_impl(__FILE__, __LINE__)
397#define HALIDE_TOC Halide::Internal::halide_toc_impl(__FILE__, __LINE__)
398#ifdef COMPILING_HALIDE
399#define TIC HALIDE_TIC
400#define TOC HALIDE_TOC
401#endif
402
403// statically cast a value from one type to another: this is really just
404// some syntactic sugar around static_cast<>() to avoid compiler warnings
405// regarding 'bool' in some compliation configurations.
406template<typename TO>
408 template<typename FROM>
409 inline constexpr static TO value(const FROM &from) {
410 if constexpr (std::is_same<TO, bool>::value) {
411 return from != 0;
412 } else {
413 return static_cast<TO>(from);
414 }
415 }
416};
417
418// Like std::is_convertible, but with additional tests for arithmetic types:
419// ensure that the value will roundtrip losslessly (e.g., no integer truncation
420// or dropping of fractional parts).
421template<typename TO>
423 template<typename FROM>
424 inline constexpr static bool value(const FROM &from) {
425 if constexpr (std::is_convertible<FROM, TO>::value) {
426 if constexpr (std::is_arithmetic<TO>::value &&
427 std::is_arithmetic<FROM>::value &&
428 !std::is_same<TO, FROM>::value) {
429 const TO to = static_cast<TO>(from);
430 const FROM roundtripped = static_cast<FROM>(to);
431 return roundtripped == from;
432 } else {
433 return true;
434 }
435 } else {
436 return false;
437 }
438 }
439};
440
441/** Emit a version of a string that is a valid identifier in C (. is replaced with _)
442 * If prefix_underscore is true (the default), an underscore will be prepended if the
443 * input starts with an alphabetic character to avoid reserved word clashes.
444 */
445std::string c_print_name(const std::string &name, bool prefix_underscore = true);
446
447/** Return the LLVM_VERSION against which this libHalide is compiled. This is provided
448 * only for internal tests which need to verify behavior; please don't use this outside
449 * of Halide tests. */
451
452} // namespace Internal
453
454/** Set how much stack the compiler should use for compilation in
455 * bytes. This can also be set through the environment variable
456 * HL_COMPILER_STACK_SIZE, though this function takes precedence. A
457 * value of zero causes the compiler to just use the calling stack for
458 * all compilation tasks.
459 *
460 * Calling this or setting the environment variable should not be
461 * necessary. It is provided for three kinds of testing:
462 *
463 * First, Halide uses it in our internal tests to make sure
464 * we're not using a silly amount of stack size on some
465 * canary programs to avoid stack usage regressions.
466 *
467 * Second, if you have a mysterious crash inside a generator, you can
468 * set a larger stack size as a way to test if it's a stack
469 * overflow. Perhaps our default stack size is not large enough for
470 * your program and schedule. Use this call or the environment var as
471 * a workaround, and then open a bug with a reproducer at
472 * github.com/halide/Halide/issues so that we can determine what's
473 * going wrong that is causing your code to use so much stack.
474 *
475 * Third, perhaps using a side-stack is causing problems with
476 * sanitizing, debugging, or profiling tools. If this is a problem,
477 * you can set HL_COMPILER_STACK_SIZE to zero to make Halide stay on
478 * the main thread's stack.
479 */
481
482/** The default amount of stack used for lowering and codegen. 32 MB
483 * ought to be enough for anyone. */
484constexpr size_t default_compiler_stack_size = 32 * 1024 * 1024;
485
486/** Return how much stack size the compiler should use for calls that
487 * go through run_with_large_stack below. Currently that's lowering
488 * and codegen. If no call to set_compiler_stack_size has been made,
489 * this checks the value of the environment variable
490 * HL_COMPILER_STACK_SIZE. If that's unset, it returns
491 * default_compiler_stack_size, defined above. */
493
494namespace Internal {
495
496/** Call the given action in a platform-specific context that
497 * provides at least the stack space returned by
498 * get_compiler_stack_size. If that value is zero, just calls the
499 * function on the calling thread. Otherwise on Windows this
500 * uses a Fiber, and on other platforms it uses swapcontext. */
501void run_with_large_stack(const std::function<void()> &action);
502
503/** Portable versions of popcount, count-leading-zeros, and
504 count-trailing-zeros. */
505// @{
509// @}
510
511} // namespace Internal
512} // namespace Halide
513
514#endif
This file declares the routines used by Halide internally in its runtime.
#define HALIDE_MUST_USE_RESULT
Definition: HalideRuntime.h:56
A simple utility class that creates a temporary file in its ctor and deletes that file in its dtor; t...
Definition: Util.h:312
TemporaryFile & operator=(TemporaryFile &&)=delete
TemporaryFile(TemporaryFile &&)=delete
TemporaryFile & operator=(const TemporaryFile &)=delete
const std::string & pathname() const
Definition: Util.h:317
TemporaryFile(const TemporaryFile &)=delete
TemporaryFile(const std::string &prefix, const std::string &suffix)
Definition: Util.h:314
void assert_file_exists(const std::string &name)
assert-fail if the file doesn't exist.
int ctz64(uint64_t x)
void file_unlink(const std::string &name)
Wrapper for unlink().
std::string make_entity_name(void *stack_ptr, const std::string &type, char prefix)
Make a unique name for an object based on the name of the stack variable passed in.
bool ends_with(const std::string &str, const std::string &suffix)
Test if the first string ends with the second string.
void run_with_large_stack(const std::function< void()> &action)
Call the given action in a platform-specific context that provides at least the stack space returned ...
void write_entire_file(const std::string &pathname, const void *source, size_t source_len)
Create or replace the contents of a file with a given pointer-and-length of memory.
std::vector< char > read_entire_file(const std::string &pathname)
Read the entire contents of a file into a vector<char>.
std::string file_make_temp(const std::string &prefix, const std::string &suffix)
Create a unique file with a name of the form prefixXXXXXsuffix in an arbitrary (but writable) directo...
int get_llvm_version()
Return the LLVM_VERSION against which this libHalide is compiled.
void dir_rmdir(const std::string &name)
Wrapper for rmdir().
std::string c_print_name(const std::string &name, bool prefix_underscore=true)
Emit a version of a string that is a valid identifier in C (.
int clz64(uint64_t x)
void halide_toc_impl(const char *file, int line)
HALIDE_MUST_USE_RESULT bool add_with_overflow(int bits, int64_t a, int64_t b, int64_t *result)
Routines to perform arithmetic on signed types without triggering signed overflow.
bool sub_would_overflow(int bits, int64_t a, int64_t b)
std::string get_env_variable(char const *env_var_name)
Get value of an environment variable.
bool add_would_overflow(int bits, int64_t a, int64_t b)
Routines to test if math would overflow for signed integers with the given number of bits.
std::string extract_namespaces(const std::string &name, std::vector< std::string > &namespaces)
Returns base name and fills in namespaces, outermost one first in vector.
HALIDE_MUST_USE_RESULT bool mul_with_overflow(int bits, int64_t a, int64_t b, int64_t *result)
void ensure_no_file_exists(const std::string &name)
Ensure that no file with this path exists.
DstType reinterpret_bits(const SrcType &src)
An aggressive form of reinterpret cast used for correct type-punning.
Definition: Util.h:133
bool mul_would_overflow(int bits, int64_t a, int64_t b)
std::string replace_all(const std::string &str, const std::string &find, const std::string &replace)
Replace all matches of the second string in the first string with the last string.
FileStat file_stat(const std::string &name)
Wrapper for stat().
std::vector< std::string > split_string(const std::string &source, const std::string &delim)
Split the source string using 'delim' as the divider.
T fold_left(const std::vector< T > &vec, Fn f)
Perform a left fold of a vector.
Definition: Util.h:192
std::string unique_name(char prefix)
Generate a unique name starting with the given prefix.
std::string running_program_name()
Get the name of the currently running executable.
DST safe_numeric_cast(SRC s)
Some numeric conversions are UB if the value won't fit in the result; safe_numeric_cast<>() is meant ...
Definition: Util.h:97
void assert_no_file_exists(const std::string &name)
assert-fail if the file DOES exist.
std::string dir_make_temp()
Create a unique directory in an arbitrary (but writable) directory; this is typically somewhere insid...
int popcount64(uint64_t x)
Portable versions of popcount, count-leading-zeros, and count-trailing-zeros.
HALIDE_MUST_USE_RESULT bool sub_with_overflow(int bits, int64_t a, int64_t b, int64_t *result)
void halide_tic_impl(const char *file, int line)
bool starts_with(const std::string &str, const std::string &prefix)
Test if the first string starts with the second string.
std::string strip_namespaces(const std::string &name)
Like extract_namespaces(), but strip and discard the namespaces, returning base name only.
T fold_right(const std::vector< T > &vec, Fn f)
Returns a right fold of a vector.
Definition: Util.h:207
bool file_exists(const std::string &name)
Wrapper for access().
This file defines the class FunctionDAG, which is our representation of a Halide pipeline,...
@ Internal
Not visible externally, similar to 'static' linkage in C.
constexpr size_t default_compiler_stack_size
The default amount of stack used for lowering and codegen.
Definition: Util.h:484
size_t get_compiler_stack_size()
Return how much stack size the compiler should use for calls that go through run_with_large_stack bel...
Expr min(const FuncRef &a, const FuncRef &b)
Explicit overloads of min and max for FuncRef.
Definition: Func.h:584
void load_plugin(const std::string &lib_name)
Load a plugin in the form of a dynamic library (e.g.
void set_compiler_stack_size(size_t)
Set how much stack the compiler should use for compilation in bytes.
Expr max(const FuncRef &a, const FuncRef &b)
Definition: Func.h:587
unsigned __INT64_TYPE__ uint64_t
signed __INT64_TYPE__ int64_t
void * memcpy(void *s1, const void *s2, size_t n)
unsigned __INT32_TYPE__ uint32_t
static constexpr bool value(const FROM &from)
Definition: Util.h:424
Helper class for saving/restoring variable values on the stack, to allow for early-exit that preserve...
Definition: Util.h:363
ScopedValue(ScopedValue &&that) noexcept=default
ScopedValue(T &var, T new_value)
Preserve the old value, then set the var to a new value.
Definition: Util.h:371
ScopedValue(T &var)
Preserve the old value, restored at dtor time.
Definition: Util.h:367
ScopedValue(const ScopedValue &that)=delete
static constexpr TO value(const FROM &from)
Definition: Util.h:409