Halide 14.0.0
Halide compiler and libraries
Function.h
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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;
20
21class Var;
22
23/** An enum to specify calling convention for extern stages. */
24enum class NameMangling {
25 Default, ///< Match whatever is specified in the Target
26 C, ///< No name mangling
27 CPlusPlus, ///< C++ name mangling
28};
29
30namespace Internal {
31
32struct Call;
33class Parameter;
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 Function from an existing FunctionContents pointer. Must be non-null */
61 explicit Function(const FunctionPtr &);
62
63 /** Get a handle on the halide function contents that this Function
64 * represents. */
66 return contents;
67 }
68
69 /** Deep copy this Function into 'copy'. It recursively deep copies all called
70 * functions, schedules, update definitions, extern func arguments, specializations,
71 * and reduction domains. This method does not deep-copy the Parameter objects.
72 * This method also takes a map of <old Function, deep-copied version> as input
73 * and would use the deep-copied Function from the map if exists instead of
74 * creating a new deep-copy to avoid creating deep-copies of the same Function
75 * multiple times. If 'name' is specified, copy's name will be set to that.
76 */
77 // @{
78 void deep_copy(const FunctionPtr &copy, std::map<FunctionPtr, FunctionPtr> &copied_map) const;
79 void deep_copy(std::string name, const FunctionPtr &copy,
80 std::map<FunctionPtr, FunctionPtr> &copied_map) const;
81 // @}
82
83 /** Add a pure definition to this function. It may not already
84 * have a definition. All the free variables in 'value' must
85 * appear in the args list. 'value' must not depend on any
86 * reduction domain */
87 void define(const std::vector<std::string> &args, std::vector<Expr> values);
88
89 /** Add an update definition to this function. It must already
90 * have a pure definition but not an update definition, and the
91 * length of args must match the length of args used in the pure
92 * definition. 'value' must depend on some reduction domain, and
93 * may contain variables from that domain as well as pure
94 * variables. Any pure variables must also appear as Variables in
95 * the args array, and they must have the same name as the pure
96 * definition's argument in the same index. */
97 void define_update(const std::vector<Expr> &args, std::vector<Expr> values);
98
99 /** Accept a visitor to visit all of the definitions and arguments
100 * of this function. */
101 void accept(IRVisitor *visitor) const;
102
103 /** Accept a mutator to mutator all of the definitions and
104 * arguments of this function. */
105 void mutate(IRMutator *mutator);
106
107 /** Get the name of the function. */
108 const std::string &name() const;
109
110 /** If this is a wrapper of another func, created by a chain of in
111 * or clone_in calls, returns the name of the original
112 * Func. Otherwise returns the name. */
113 const std::string &origin_name() const;
114
115 /** Get a mutable handle to the init definition. */
117
118 /** Get the init definition. */
119 const Definition &definition() const;
120
121 /** Get the pure arguments. */
122 const std::vector<std::string> &args() const;
123
124 /** Get the dimensionality. */
125 int dimensions() const;
126
127 /** Get the number of outputs. */
128 int outputs() const {
129 return (int)output_types().size();
130 }
131
132 /** Get the types of the outputs. */
133 const std::vector<Type> &output_types() const;
134
135 /** Get the right-hand-side of the pure definition. Returns an
136 * empty vector if there is no pure definition. */
137 const std::vector<Expr> &values() const;
138
139 /** Does this function have a pure definition? */
141
142 /** Does this function *only* have a pure definition? */
143 bool is_pure() const {
144 return (has_pure_definition() &&
147 }
148
149 /** Is it legal to inline this function? */
150 bool can_be_inlined() const;
151
152 /** Get a handle to the function-specific schedule for the purpose
153 * of modifying it. */
155
156 /** Get a const handle to the function-specific schedule for inspecting it. */
157 const FuncSchedule &schedule() const;
158
159 /** Get a handle on the output buffer used for setting constraints
160 * on it. */
161 const std::vector<Parameter> &output_buffers() const;
162
163 /** Get a mutable handle to the stage-specfic schedule for the update
164 * stage. */
166
167 /** Get a mutable handle to this function's update definition at
168 * index 'idx'. */
169 Definition &update(int idx = 0);
170
171 /** Get a const reference to this function's update definition at
172 * index 'idx'. */
173 const Definition &update(int idx = 0) const;
174
175 /** Get a const reference to this function's update definitions. */
176 const std::vector<Definition> &updates() const;
177
178 /** Does this function have an update definition? */
180
181 /** Check if the function has an extern definition. */
183
184 /** Get the name mangling specified for the extern definition. */
186
187 /** Make a call node to the extern definition. An error if the
188 * function has no extern definition. */
189 Expr make_call_to_extern_definition(const std::vector<Expr> &args,
190 const Target &t) const;
191
192 /** Get the proxy Expr for the extern stage. This is an expression
193 * known to have the same data access pattern as the extern
194 * stage. It must touch at least all of the memory that the extern
195 * stage does, though it is permissible for it to be conservative
196 * and touch a superset. For most Functions, including those with
197 * extern definitions, this will be an undefined Expr. */
198 // @{
201 // @}
202
203 /** Add an external definition of this Func. */
204 void define_extern(const std::string &function_name,
205 const std::vector<ExternFuncArgument> &args,
206 const std::vector<Type> &types,
207 const std::vector<Var> &dims,
208 NameMangling mangling, DeviceAPI device_api);
209
210 /** Retrive the arguments of the extern definition. */
211 // @{
212 const std::vector<ExternFuncArgument> &extern_arguments() const;
213 std::vector<ExternFuncArgument> &extern_arguments();
214 // @}
215
216 /** Get the name of the extern function called for an extern
217 * definition. */
218 const std::string &extern_function_name() const;
219
220 /** Get the DeviceAPI declared for an extern function. */
222
223 /** Test for equality of identity. */
224 bool same_as(const Function &other) const {
225 return contents.same_as(other.contents);
226 }
227
228 /** Get a const handle to the debug filename. */
229 const std::string &debug_file() const;
230
231 /** Get a handle to the debug filename. */
232 std::string &debug_file();
233
234 /** Use an an extern argument to another function. */
235 operator ExternFuncArgument() const;
236
237 /** Tracing calls and accessors, passed down from the Func
238 * equivalents. */
239 // @{
243 void add_trace_tag(const std::string &trace_tag);
244 bool is_tracing_loads() const;
245 bool is_tracing_stores() const;
247 const std::vector<std::string> &get_trace_tags() const;
248 // @}
249
250 /** Replace this Function's LoopLevels with locked copies that
251 * cannot be mutated further. */
253
254 /** Mark function as frozen, which means it cannot accept new
255 * definitions. */
256 void freeze();
257
258 /** Check if a function has been frozen. If so, it is an error to
259 * add new definitions. */
260 bool frozen() const;
261
262 /** Make a new Function with the same lifetime as this one, and
263 * return a strong reference to it. Useful to create Functions which
264 * have circular references to this one - e.g. the wrappers
265 * produced by Func::in. */
267
268 /** Mark calls of this function by 'f' to be replaced with its wrapper
269 * during the lowering stage. If the string 'f' is empty, it means replace
270 * all calls to this function by all other functions (excluding itself) in
271 * the pipeline with the wrapper. This will also freeze 'wrapper' to prevent
272 * user from updating the values of the Function it wraps via the wrapper.
273 * See \ref Func::in for more details. */
274 // @{
275 void add_wrapper(const std::string &f, Function &wrapper);
276 const std::map<std::string, FunctionPtr> &wrappers() const;
277 // @}
278
279 /** Check if a Function is a trivial wrapper around another
280 * Function, Buffer, or Parameter. Returns the Call node if it
281 * is. Otherwise returns null.
282 */
283 const Call *is_wrapper() const;
284
285 /** Replace every call to Functions in 'substitutions' keys by all Exprs
286 * referenced in this Function to call to their substitute Functions (i.e.
287 * the corresponding values in 'substitutions' map). */
288 // @{
289 Function &substitute_calls(const std::map<FunctionPtr, FunctionPtr> &substitutions);
291 // @}
292
293 /** Return true iff the name matches one of the Function's pure args. */
294 bool is_pure_arg(const std::string &name) const;
295};
296
297/** Deep copy an entire Function DAG. */
298std::pair<std::vector<Function>, std::map<std::string, Function>> deep_copy(
299 const std::vector<Function> &outputs,
300 const std::map<std::string, Function> &env);
301
302} // namespace Internal
303} // namespace Halide
304
305#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:543
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:65
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.
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.
Definition: Function.h:128
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'.
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.
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:143
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.
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 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:224
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 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.
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.
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:646
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.
This file defines the class FunctionDAG, which is our representation of a Halide pipeline,...
NameMangling
An enum to specify calling convention for extern stages.
Definition: Function.h:24
@ 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:256
An argument to an extern-defined Func.
A function call.
Definition: IR.h:466
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