Function.h
#ifndef HALIDE_FUNCTION_H
#define HALIDE_FUNCTION_H
/** \file
* Defines the internal representation of a halide function and related classes
*/
#include <map>
#include <string>
#include <utility>
#include <vector>
#include "Definition.h"
#include "Expr.h"
#include "FunctionPtr.h"
#include "Schedule.h"
namespace Halide {
struct ExternFuncArgument;
class Var;
/** An enum to specify calling convention for extern stages. */
enum class NameMangling {
Default, ///< Match whatever is specified in the Target
C, ///< No name mangling
CPlusPlus, ///< C++ name mangling
};
namespace Internal {
struct Call;
class Parameter;
/** A reference-counted handle to Halide's internal representation of
* a function. Similar to a front-end Func object, but with no
* syntactic sugar to help with definitions. */
class Function {
FunctionPtr contents;
public:
/** This lets you use a Function as a key in a map of the form
* map<Function, Foo, Function::Compare> */
struct Compare {
bool operator()(const Function &a, const Function &b) const {
internal_assert(a.contents.defined() && b.contents.defined());
return a.contents < b.contents;
}
};
/** Construct a new function with no definitions and no name. This
* constructor only exists so that you can make vectors of
* functions, etc.
*/
Function() = default;
/** Construct a new function with the given name */
explicit Function(const std::string &n);
/** Construct a Function from an existing FunctionContents pointer. Must be non-null */
explicit Function(const FunctionPtr &);
/** Get a handle on the halide function contents that this Function
* represents. */
FunctionPtr get_contents() const {
return contents;
}
/** Deep copy this Function into 'copy'. It recursively deep copies all called
* functions, schedules, update definitions, extern func arguments, specializations,
* and reduction domains. This method does not deep-copy the Parameter objects.
* This method also takes a map of <old Function, deep-copied version> as input
* and would use the deep-copied Function from the map if exists instead of
* creating a new deep-copy to avoid creating deep-copies of the same Function
* multiple times. If 'name' is specified, copy's name will be set to that.
*/
// @{
void deep_copy(const FunctionPtr ©, std::map<FunctionPtr, FunctionPtr> &copied_map) const;
void deep_copy(std::string name, const FunctionPtr ©,
std::map<FunctionPtr, FunctionPtr> &copied_map) const;
// @}
/** Add a pure definition to this function. It may not already
* have a definition. All the free variables in 'value' must
* appear in the args list. 'value' must not depend on any
* reduction domain */
void define(const std::vector<std::string> &args, std::vector<Expr> values);
/** Add an update definition to this function. It must already
* have a pure definition but not an update definition, and the
* length of args must match the length of args used in the pure
* definition. 'value' must depend on some reduction domain, and
* may contain variables from that domain as well as pure
* variables. Any pure variables must also appear as Variables in
* the args array, and they must have the same name as the pure
* definition's argument in the same index. */
void define_update(const std::vector<Expr> &args, std::vector<Expr> values);
/** Accept a visitor to visit all of the definitions and arguments
* of this function. */
void accept(IRVisitor *visitor) const;
/** Accept a mutator to mutator all of the definitions and
* arguments of this function. */
void mutate(IRMutator *mutator);
/** Get the name of the function. */
const std::string &name() const;
/** If this is a wrapper of another func, created by a chain of in
* or clone_in calls, returns the name of the original
* Func. Otherwise returns the name. */
const std::string &origin_name() const;
/** Get a mutable handle to the init definition. */
Definition &definition();
/** Get the init definition. */
const Definition &definition() const;
/** Get the pure arguments. */
const std::vector<std::string> &args() const;
/** Get the dimensionality. */
int dimensions() const;
/** Get the number of outputs. */
int outputs() const {
return (int)output_types().size();
}
/** Get the types of the outputs. */
const std::vector<Type> &output_types() const;
/** Get the right-hand-side of the pure definition. Returns an
* empty vector if there is no pure definition. */
const std::vector<Expr> &values() const;
/** Does this function have a pure definition? */
bool has_pure_definition() const;
/** Does this function *only* have a pure definition? */
bool is_pure() const {
return (has_pure_definition() &&
!has_update_definition() &&
!has_extern_definition());
}
/** Is it legal to inline this function? */
bool can_be_inlined() const;
/** Get a handle to the function-specific schedule for the purpose
* of modifying it. */
FuncSchedule &schedule();
/** Get a const handle to the function-specific schedule for inspecting it. */
const FuncSchedule &schedule() const;
/** Get a handle on the output buffer used for setting constraints
* on it. */
const std::vector<Parameter> &output_buffers() const;
/** Get a mutable handle to the stage-specfic schedule for the update
* stage. */
StageSchedule &update_schedule(int idx = 0);
/** Get a mutable handle to this function's update definition at
* index 'idx'. */
Definition &update(int idx = 0);
/** Get a const reference to this function's update definition at
* index 'idx'. */
const Definition &update(int idx = 0) const;
/** Get a const reference to this function's update definitions. */
const std::vector<Definition> &updates() const;
/** Does this function have an update definition? */
bool has_update_definition() const;
/** Check if the function has an extern definition. */
bool has_extern_definition() const;
/** Get the name mangling specified for the extern definition. */
NameMangling extern_definition_name_mangling() const;
/** Make a call node to the extern definition. An error if the
* function has no extern definition. */
Expr make_call_to_extern_definition(const std::vector<Expr> &args,
const Target &t) const;
/** Get the proxy Expr for the extern stage. This is an expression
* known to have the same data access pattern as the extern
* stage. It must touch at least all of the memory that the extern
* stage does, though it is permissible for it to be conservative
* and touch a superset. For most Functions, including those with
* extern definitions, this will be an undefined Expr. */
// @{
Expr extern_definition_proxy_expr() const;
Expr &extern_definition_proxy_expr();
// @}
/** Add an external definition of this Func. */
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);
/** Retrive the arguments of the extern definition. */
// @{
const std::vector<ExternFuncArgument> &extern_arguments() const;
std::vector<ExternFuncArgument> &extern_arguments();
// @}
/** Get the name of the extern function called for an extern
* definition. */
const std::string &extern_function_name() const;
/** Get the DeviceAPI declared for an extern function. */
DeviceAPI extern_function_device_api() const;
/** Test for equality of identity. */
bool same_as(const Function &other) const {
return contents.same_as(other.contents);
}
/** Get a const handle to the debug filename. */
const std::string &debug_file() const;
/** Get a handle to the debug filename. */
std::string &debug_file();
/** Use an an extern argument to another function. */
operator ExternFuncArgument() const;
/** Tracing calls and accessors, passed down from the Func
* equivalents. */
// @{
void trace_loads();
void trace_stores();
void trace_realizations();
void add_trace_tag(const std::string &trace_tag);
bool is_tracing_loads() const;
bool is_tracing_stores() const;
bool is_tracing_realizations() const;
const std::vector<std::string> &get_trace_tags() const;
// @}
/** Replace this Function's LoopLevels with locked copies that
* cannot be mutated further. */
void lock_loop_levels();
/** Mark function as frozen, which means it cannot accept new
* definitions. */
void freeze();
/** Check if a function has been frozen. If so, it is an error to
* add new definitions. */
bool frozen() const;
/** Make a new Function with the same lifetime as this one, and
* return a strong reference to it. Useful to create Functions which
* have circular references to this one - e.g. the wrappers
* produced by Func::in. */
Function new_function_in_same_group(const std::string &);
/** Mark calls of this function by 'f' to be replaced with its wrapper
* during the lowering stage. If the string 'f' is empty, it means replace
* all calls to this function by all other functions (excluding itself) in
* the pipeline with the wrapper. This will also freeze 'wrapper' to prevent
* user from updating the values of the Function it wraps via the wrapper.
* See \ref Func::in for more details. */
// @{
void add_wrapper(const std::string &f, Function &wrapper);
const std::map<std::string, FunctionPtr> &wrappers() const;
// @}
/** Check if a Function is a trivial wrapper around another
* Function, Buffer, or Parameter. Returns the Call node if it
* is. Otherwise returns null.
*/
const Call *is_wrapper() const;
/** Replace every call to Functions in 'substitutions' keys by all Exprs
* referenced in this Function to call to their substitute Functions (i.e.
* the corresponding values in 'substitutions' map). */
// @{
Function &substitute_calls(const std::map<FunctionPtr, FunctionPtr> &substitutions);
Function &substitute_calls(const Function &orig, const Function &substitute);
// @}
/** Return true iff the name matches one of the Function's pure args. */
bool is_pure_arg(const std::string &name) const;
};
/** Deep copy an entire Function DAG. */
std::pair<std::vector<Function>, std::map<std::string, Function>> deep_copy(
const std::vector<Function> &outputs,
const std::map<std::string, Function> &env);
} // namespace Internal
} // namespace Halide
#endif
