Halide 17.0.0
Halide compiler and libraries
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Function.h
Go to the documentation of this file.
1#ifndef HALIDE_FUNCTION_H
2#define HALIDE_FUNCTION_H
3
4/** \file
5 * Defines the internal representation of a halide function and related classes
6 */
7#include <map>
8#include <string>
9#include <utility>
10#include <vector>
11
12#include "Definition.h"
13#include "Expr.h"
14#include "FunctionPtr.h"
15#include "Schedule.h"
16
17namespace Halide {
18
19struct ExternFuncArgument;
20class Parameter;
21class Tuple;
22class Var;
23
24/** An enum to specify calling convention for extern stages. */
25enum class NameMangling {
26 Default, ///< Match whatever is specified in the Target
27 C, ///< No name mangling
28 CPlusPlus, ///< C++ name mangling
29};
30
31namespace Internal {
32
33struct Call;
34
35/** A reference-counted handle to Halide's internal representation of
36 * a function. Similar to a front-end Func object, but with no
37 * syntactic sugar to help with definitions. */
38class Function {
39 FunctionPtr contents;
40
41public:
42 /** This lets you use a Function as a key in a map of the form
43 * map<Function, Foo, Function::Compare> */
44 struct Compare {
45 bool operator()(const Function &a, const Function &b) const {
46 internal_assert(a.contents.defined() && b.contents.defined());
47 return a.contents < b.contents;
48 }
49 };
50
51 /** Construct a new function with no definitions and no name. This
52 * constructor only exists so that you can make vectors of
53 * functions, etc.
54 */
55 Function() = default;
56
57 /** Construct a new function with the given name */
58 explicit Function(const std::string &n);
59
60 /** Construct a new function with the given name,
61 * with a requirement that it can only represent Expr(s) of the given type(s),
62 * and must have exactly the give nnumber of dimensions.
63 * required_types.empty() means there are no constraints on the type(s).
64 * required_dims == AnyDims means there are no constraints on the dimensions. */
65 explicit Function(const std::vector<Type> &required_types, int required_dims, const std::string &n);
66
67 /** Construct a Function from an existing FunctionContents pointer. Must be non-null */
68 explicit Function(const FunctionPtr &);
69
70 /** Update a function with deserialized data */
71 void update_with_deserialization(const std::string &name,
72 const std::string &origin_name,
73 const std::vector<Halide::Type> &output_types,
74 const std::vector<Halide::Type> &required_types,
75 int required_dims,
76 const std::vector<std::string> &args,
78 const Definition &init_def,
79 const std::vector<Definition> &updates,
80 const std::string &debug_file,
81 const std::vector<Parameter> &output_buffers,
82 const std::vector<ExternFuncArgument> &extern_arguments,
83 const std::string &extern_function_name,
84 NameMangling name_mangling,
85 DeviceAPI device_api,
87 bool trace_loads,
88 bool trace_stores,
90 const std::vector<std::string> &trace_tags,
91 bool frozen);
92
93 /** Get a handle on the halide function contents that this Function
94 * represents. */
96 return contents;
97 }
98
99 /** Deep copy this Function into 'copy'. It recursively deep copies all called
100 * functions, schedules, update definitions, extern func arguments, specializations,
101 * and reduction domains. This method does not deep-copy the Parameter objects.
102 * This method also takes a map of <old Function, deep-copied version> as input
103 * and would use the deep-copied Function from the map if exists instead of
104 * creating a new deep-copy to avoid creating deep-copies of the same Function
105 * multiple times. If 'name' is specified, copy's name will be set to that.
106 */
107 // @{
108 void deep_copy(const FunctionPtr &copy, std::map<FunctionPtr, FunctionPtr> &copied_map) const;
109 void deep_copy(std::string name, const FunctionPtr &copy,
110 std::map<FunctionPtr, FunctionPtr> &copied_map) const;
111 // @}
112
113 /** Add a pure definition to this function. It may not already
114 * have a definition. All the free variables in 'value' must
115 * appear in the args list. 'value' must not depend on any
116 * reduction domain */
117 void define(const std::vector<std::string> &args, std::vector<Expr> values);
118
119 /** Add an update definition to this function. It must already
120 * have a pure definition but not an update definition, and the
121 * length of args must match the length of args used in the pure
122 * definition. 'value' must depend on some reduction domain, and
123 * may contain variables from that domain as well as pure
124 * variables. Any pure variables must also appear as Variables in
125 * the args array, and they must have the same name as the pure
126 * definition's argument in the same index. */
127 void define_update(const std::vector<Expr> &args, std::vector<Expr> values);
128
129 /** Accept a visitor to visit all of the definitions and arguments
130 * of this function. */
132
133 /** Accept a mutator to mutator all of the definitions and
134 * arguments of this function. */
136
137 /** Get the name of the function. */
138 const std::string &name() const;
139
140 /** If this is a wrapper of another func, created by a chain of in
141 * or clone_in calls, returns the name of the original
142 * Func. Otherwise returns the name. */
143 const std::string &origin_name() const;
144
145 /** Get a mutable handle to the init definition. */
147
148 /** Get the init definition. */
149 const Definition &definition() const;
150
151 /** Get the pure arguments. */
152 const std::vector<std::string> &args() const;
153
154 /** Get the dimensionality. */
155 int dimensions() const;
156
157 /** Get the number of outputs. */
158 int outputs() const;
159
160 /** Get the types of the outputs. */
161 const std::vector<Type> &output_types() const;
162
163 /** Get the type constaints on the outputs (if any). */
164 const std::vector<Type> &required_types() const;
165
166 /** Get the dimensionality constaints on the outputs (if any). */
168
169 /** Get the right-hand-side of the pure definition. Returns an
170 * empty vector if there is no pure definition.
171 *
172 * Warning: Any Vars in the Exprs are not qualified with the Func name, so
173 * the Exprs may contain names which collide with names provided by
174 * unique_name.
175 */
176 const std::vector<Expr> &values() const;
177
178 /** Does this function have a pure definition? */
180
181 /** Does this function *only* have a pure definition? */
182 bool is_pure() const {
183 return (has_pure_definition() &&
186 }
187
188 /** Is it legal to inline this function? */
189 bool can_be_inlined() const;
190
191 /** Get a handle to the function-specific schedule for the purpose
192 * of modifying it. */
194
195 /** Get a const handle to the function-specific schedule for inspecting it. */
196 const FuncSchedule &schedule() const;
197
198 /** Get a handle on the output buffer used for setting constraints
199 * on it. */
200 const std::vector<Parameter> &output_buffers() const;
201
202 /** Get a mutable handle to the stage-specfic schedule for the update
203 * stage. */
205
206 /** Get a mutable handle to this function's update definition at
207 * index 'idx'. */
208 Definition &update(int idx = 0);
209
210 /** Get a const reference to this function's update definition at
211 * index 'idx'. */
212 const Definition &update(int idx = 0) const;
213
214 /** Get a const reference to this function's update definitions. */
215 const std::vector<Definition> &updates() const;
216
217 /** Does this function have an update definition? */
219
220 /** Check if the function has an extern definition. */
222
223 /** Get the name mangling specified for the extern definition. */
225
226 /** Make a call node to the extern definition. An error if the
227 * function has no extern definition. */
228 Expr make_call_to_extern_definition(const std::vector<Expr> &args,
229 const Target &t) const;
230
231 /** Get the proxy Expr for the extern stage. This is an expression
232 * known to have the same data access pattern as the extern
233 * stage. It must touch at least all of the memory that the extern
234 * stage does, though it is permissible for it to be conservative
235 * and touch a superset. For most Functions, including those with
236 * extern definitions, this will be an undefined Expr. */
237 // @{
240 // @}
241
242 /** Add an external definition of this Func. */
243 void define_extern(const std::string &function_name,
244 const std::vector<ExternFuncArgument> &args,
245 const std::vector<Type> &types,
246 const std::vector<Var> &dims,
247 NameMangling mangling, DeviceAPI device_api);
248
249 /** Retrive the arguments of the extern definition. */
250 // @{
251 const std::vector<ExternFuncArgument> &extern_arguments() const;
252 std::vector<ExternFuncArgument> &extern_arguments();
253 // @}
254
255 /** Get the name of the extern function called for an extern
256 * definition. */
257 const std::string &extern_function_name() const;
258
259 /** Get the DeviceAPI declared for an extern function. */
261
262 /** Test for equality of identity. */
263 bool same_as(const Function &other) const {
264 return contents.same_as(other.contents);
265 }
266
267 /** Get a const handle to the debug filename. */
268 const std::string &debug_file() const;
269
270 /** Get a handle to the debug filename. */
271 std::string &debug_file();
272
273 /** Use an an extern argument to another function. */
274 operator ExternFuncArgument() const;
275
276 /** Tracing calls and accessors, passed down from the Func
277 * equivalents. */
278 // @{
282 void add_trace_tag(const std::string &trace_tag);
283 bool is_tracing_loads() const;
284 bool is_tracing_stores() const;
286 const std::vector<std::string> &get_trace_tags() const;
287 // @}
288
289 /** Replace this Function's LoopLevels with locked copies that
290 * cannot be mutated further. */
292
293 /** Mark function as frozen, which means it cannot accept new
294 * definitions. */
295 void freeze();
296
297 /** Check if a function has been frozen. If so, it is an error to
298 * add new definitions. */
299 bool frozen() const;
300
301 /** Make a new Function with the same lifetime as this one, and
302 * return a strong reference to it. Useful to create Functions which
303 * have circular references to this one - e.g. the wrappers
304 * produced by Func::in. */
306
307 /** Mark calls of this function by 'f' to be replaced with its wrapper
308 * during the lowering stage. If the string 'f' is empty, it means replace
309 * all calls to this function by all other functions (excluding itself) in
310 * the pipeline with the wrapper. This will also freeze 'wrapper' to prevent
311 * user from updating the values of the Function it wraps via the wrapper.
312 * See \ref Func::in for more details. */
313 // @{
314 void add_wrapper(const std::string &f, Function &wrapper);
315 const std::map<std::string, FunctionPtr> &wrappers() const;
316 // @}
317
318 /** Check if a Function is a trivial wrapper around another
319 * Function, Buffer, or Parameter. Returns the Call node if it
320 * is. Otherwise returns null.
321 */
322 const Call *is_wrapper() const;
323
324 /** Replace every call to Functions in 'substitutions' keys by all Exprs
325 * referenced in this Function to call to their substitute Functions (i.e.
326 * the corresponding values in 'substitutions' map). */
327 // @{
328 Function &substitute_calls(const std::map<FunctionPtr, FunctionPtr> &substitutions);
330 // @}
331
332 /** Return true iff the name matches one of the Function's pure args. */
333 bool is_pure_arg(const std::string &name) const;
334
335 /** If the Function has type requirements, check that the given argument
336 * is compatible with them. If not, assert-fail. (If there are no type requirements, do nothing.) */
337 void check_types(const Expr &e) const;
338 void check_types(const Tuple &t) const;
339 void check_types(const Type &t) const;
340 void check_types(const std::vector<Expr> &exprs) const;
341 void check_types(const std::vector<Type> &types) const;
342
343 /** If the Function has dimension requirements, check that the given argument
344 * is compatible with them. If not, assert-fail. (If there are no dimension requirements, do nothing.) */
345 void check_dims(int dims) const;
346
347 /** Define the output buffers. If the Function has types specified, this can be called at
348 * any time. If not, it can only be called for a Function with a pure definition. */
349 void create_output_buffers(const std::vector<Type> &types, int dims) const;
350};
351
352/** Deep copy an entire Function DAG. */
353std::pair<std::vector<Function>, std::map<std::string, Function>> deep_copy(
354 const std::vector<Function> &outputs,
355 const std::map<std::string, Function> &env);
356
357extern std::atomic<int> random_variable_counter;
358
359} // namespace Internal
360} // namespace Halide
361
362#endif
Defines the internal representation of a halide function's definition and related classes.
#define internal_assert(c)
Definition Errors.h:19
Base classes for Halide expressions (Halide::Expr) and statements (Halide::Internal::Stmt)
Defines the internal representation of the schedule for a function.
A Function definition which can either represent a init or an update definition.
Definition Definition.h:38
A schedule for a Function of a Halide pipeline.
Definition Schedule.h:590
A reference-counted handle to Halide's internal representation of a function.
Definition Function.h:38
const std::vector< ExternFuncArgument > & extern_arguments() const
Retrive the arguments of the extern definition.
const std::string & extern_function_name() const
Get the name of the extern function called for an extern definition.
FunctionPtr get_contents() const
Get a handle on the halide function contents that this Function represents.
Definition Function.h:95
void define(const std::vector< std::string > &args, std::vector< Expr > values)
Add a pure definition to this function.
void deep_copy(const FunctionPtr &copy, std::map< FunctionPtr, FunctionPtr > &copied_map) const
Deep copy this Function into 'copy'.
bool frozen() const
Check if a function has been frozen.
DeviceAPI extern_function_device_api() const
Get the DeviceAPI declared for an extern function.
Function(const std::string &n)
Construct a new function with the given name.
int dimensions() const
Get the dimensionality.
void check_types(const Type &t) const
bool is_tracing_realizations() const
bool has_extern_definition() const
Check if the function has an extern definition.
int outputs() const
Get the number of outputs.
int required_dimensions() const
Get the dimensionality constaints on the outputs (if any).
Function & substitute_calls(const std::map< FunctionPtr, FunctionPtr > &substitutions)
Replace every call to Functions in 'substitutions' keys by all Exprs referenced in this Function to c...
const std::map< std::string, FunctionPtr > & wrappers() const
const Definition & update(int idx=0) const
Get a const reference to this function's update definition at index 'idx'.
const std::vector< Type > & required_types() const
Get the type constaints on the outputs (if any).
void lock_loop_levels()
Replace this Function's LoopLevels with locked copies that cannot be mutated further.
bool can_be_inlined() const
Is it legal to inline this function?
StageSchedule & update_schedule(int idx=0)
Get a mutable handle to the stage-specfic schedule for the update stage.
bool is_tracing_stores() const
std::string & debug_file()
Get a handle to the debug filename.
const Call * is_wrapper() const
Check if a Function is a trivial wrapper around another Function, Buffer, or Parameter.
bool has_pure_definition() const
Does this function have a pure definition?
FuncSchedule & schedule()
Get a handle to the function-specific schedule for the purpose of modifying it.
const std::vector< Parameter > & output_buffers() const
Get a handle on the output buffer used for setting constraints on it.
const Definition & definition() const
Get the init definition.
void check_dims(int dims) const
If the Function has dimension requirements, check that the given argument is compatible with them.
Function()=default
Construct a new function with no definitions and no name.
bool is_pure() const
Does this function only have a pure definition?
Definition Function.h:182
bool has_update_definition() const
Does this function have an update definition?
void trace_loads()
Tracing calls and accessors, passed down from the Func equivalents.
std::vector< ExternFuncArgument > & extern_arguments()
const FuncSchedule & schedule() const
Get a const handle to the function-specific schedule for inspecting it.
Function new_function_in_same_group(const std::string &)
Make a new Function with the same lifetime as this one, and return a strong reference to it.
const std::vector< Definition > & updates() const
Get a const reference to this function's update definitions.
Definition & definition()
Get a mutable handle to the init definition.
void check_types(const std::vector< Expr > &exprs) const
void create_output_buffers(const std::vector< Type > &types, int dims) const
Define the output buffers.
void update_with_deserialization(const std::string &name, const std::string &origin_name, const std::vector< Halide::Type > &output_types, const std::vector< Halide::Type > &required_types, int required_dims, const std::vector< std::string > &args, const FuncSchedule &func_schedule, const Definition &init_def, const std::vector< Definition > &updates, const std::string &debug_file, const std::vector< Parameter > &output_buffers, const std::vector< ExternFuncArgument > &extern_arguments, const std::string &extern_function_name, NameMangling name_mangling, DeviceAPI device_api, const Expr &extern_proxy_expr, bool trace_loads, bool trace_stores, bool trace_realizations, const std::vector< std::string > &trace_tags, bool frozen)
Update a function with deserialized data.
const std::vector< std::string > & args() const
Get the pure arguments.
void mutate(IRMutator *mutator)
Accept a mutator to mutator all of the definitions and arguments of this function.
void define_extern(const std::string &function_name, const std::vector< ExternFuncArgument > &args, const std::vector< Type > &types, const std::vector< Var > &dims, NameMangling mangling, DeviceAPI device_api)
Add an external definition of this Func.
void check_types(const Expr &e) const
If the Function has type requirements, check that the given argument is compatible with them.
void deep_copy(std::string name, const FunctionPtr &copy, std::map< FunctionPtr, FunctionPtr > &copied_map) const
Definition & update(int idx=0)
Get a mutable handle to this function's update definition at index 'idx'.
NameMangling extern_definition_name_mangling() const
Get the name mangling specified for the extern definition.
void define_update(const std::vector< Expr > &args, std::vector< Expr > values)
Add an update definition to this function.
void accept(IRVisitor *visitor) const
Accept a visitor to visit all of the definitions and arguments of this function.
bool same_as(const Function &other) const
Test for equality of identity.
Definition Function.h:263
const std::vector< Type > & output_types() const
Get the types of the outputs.
bool is_pure_arg(const std::string &name) const
Return true iff the name matches one of the Function's pure args.
const std::vector< std::string > & get_trace_tags() const
void check_types(const Tuple &t) const
void freeze()
Mark function as frozen, which means it cannot accept new definitions.
const std::vector< Expr > & values() const
Get the right-hand-side of the pure definition.
Function & substitute_calls(const Function &orig, const Function &substitute)
const std::string & debug_file() const
Get a const handle to the debug filename.
void add_wrapper(const std::string &f, Function &wrapper)
Mark calls of this function by 'f' to be replaced with its wrapper during the lowering stage.
void check_types(const std::vector< Type > &types) const
Expr make_call_to_extern_definition(const std::vector< Expr > &args, const Target &t) const
Make a call node to the extern definition.
Function(const FunctionPtr &)
Construct a Function from an existing FunctionContents pointer.
const std::string & origin_name() const
If this is a wrapper of another func, created by a chain of in or clone_in calls, returns the name of...
const std::string & name() const
Get the name of the function.
void add_trace_tag(const std::string &trace_tag)
Expr extern_definition_proxy_expr() const
Get the proxy Expr for the extern stage.
Function(const std::vector< Type > &required_types, int required_dims, const std::string &n)
Construct a new function with the given name, with a requirement that it can only represent Expr(s) o...
A base class for passes over the IR which modify it (e.g.
Definition IRMutator.h:26
A base class for algorithms that need to recursively walk over the IR.
Definition IRVisitor.h:19
A schedule for a single stage of a Halide pipeline.
Definition Schedule.h:695
Create a small array of Exprs for defining and calling functions with multiple outputs.
Definition Tuple.h:18
std::pair< std::vector< Function >, std::map< std::string, Function > > deep_copy(const std::vector< Function > &outputs, const std::map< std::string, Function > &env)
Deep copy an entire Function DAG.
Expr substitute(const std::string &name, const Expr &replacement, const Expr &expr)
Substitute variables with the given name with the replacement expression within expr.
std::atomic< int > random_variable_counter
This file defines the class FunctionDAG, which is our representation of a Halide pipeline,...
Expr cast(Expr a)
Cast an expression to the halide type corresponding to the C++ type T.
Definition IROperator.h:364
NameMangling
An enum to specify calling convention for extern stages.
Definition Function.h:25
@ C
No name mangling.
@ CPlusPlus
C++ name mangling.
@ Default
Match whatever is specified in the Target.
DeviceAPI
An enum describing a type of device API.
Definition DeviceAPI.h:15
A fragment of Halide syntax.
Definition Expr.h:258
An argument to an extern-defined Func.
A function call.
Definition IR.h:490
This lets you use a Function as a key in a map of the form map<Function, Foo, Function::Compare>
Definition Function.h:44
bool operator()(const Function &a, const Function &b) const
Definition Function.h:45
A possibly-weak pointer to a Halide function.
Definition FunctionPtr.h:27
bool defined() const
Check if the reference is defined.
Definition FunctionPtr.h:74
bool same_as(const FunctionPtr &other) const
Check if two FunctionPtrs refer to the same Function.
Definition FunctionPtr.h:79
A struct representing a target machine and os to generate code for.
Definition Target.h:19
Types in the halide type system.
Definition Type.h:276