Halide 19.0.0
Halide compiler and libraries
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CodeGen_C.h
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1#ifndef HALIDE_CODEGEN_C_H
2#define HALIDE_CODEGEN_C_H
3
4/** \file
5 *
6 * Defines an IRPrinter that emits C++ code equivalent to a halide stmt
7 */
8
9#include "IRPrinter.h"
10#include "Scope.h"
11#include "Target.h"
12
13namespace Halide {
14
15struct Argument;
16class Module;
17
18namespace Internal {
19
20struct LoweredFunc;
21
22/** This class emits C++ code equivalent to a halide Stmt. It's
23 * mostly the same as an IRPrinter, but it's wrapped in a function
24 * definition, and some things are handled differently to be valid
25 * C++.
26 */
27class CodeGen_C : public IRPrinter {
28public:
38
39 /** Initialize a C code generator pointing at a particular output
40 * stream (e.g. a file, or std::cout) */
41 CodeGen_C(std::ostream &dest,
42 const Target &target,
44 const std::string &include_guard = "");
45 ~CodeGen_C() override;
46
47 /** Emit the declarations contained in the module as C code. */
48 void compile(const Module &module);
49
50 /** The target we're generating code for */
51 const Target &get_target() const {
52 return target;
53 }
54
55 static void test();
56
57protected:
58 enum class IntegerSuffixStyle {
59 PlainC = 0,
60 OpenCL = 1,
61 HLSL = 2
62 };
63
64 /** How to emit 64-bit integer constants */
66
67 /** Emit a declaration. */
68 // @{
69 void compile(const LoweredFunc &func, const MetadataNameMap &metadata_name_map);
70 void compile(const Buffer<> &buffer);
71 // @}
72
73 /** This is a hook that subclasses can use to transform a function body
74 * just before it is emitted -- e.g., to transform the IR to code that
75 * is easier to recognize and emit. The default implementation simply
76 * returns the input unchanged.
77 *
78 * This hook will always be called after the function declaration and
79 * opening brace is emitted, so in addition to (possibly) returning
80 * a modified Stmt, this function may also emit C++ code to the default
81 * stream if it wishes to add some prologue at the start of the function.
82 */
84
85 /** An ID for the most recently generated ssa variable */
86 std::string id;
87
88 /** The target being generated for. */
90
91 /** Controls whether this instance is generating declarations or
92 * definitions and whether the interface us extern "C" or C++. */
94
95 /** A cache of generated values in scope */
96 std::map<std::string, std::string> cache;
97
98 /** Emit an expression as an assignment, then return the id of the
99 * resulting var */
100 std::string print_expr(const Expr &);
101
102 /** Like print_expr, but cast the Expr to the given Type */
103 std::string print_cast_expr(const Type &, const Expr &);
104
105 /** Emit a statement */
106 void print_stmt(const Stmt &);
107
108 void create_assertion(const std::string &id_cond, const Expr &message);
109 void create_assertion(const Expr &cond, const Expr &message);
110
116
117 /** Emit the C name for a halide type. If space_option is AppendSpace,
118 * and there should be a space between the type and the next token,
119 * one is appended. (This allows both "int foo" and "Foo *foo" to be
120 * formatted correctly. Otherwise the latter is "Foo * foo".)
121 */
122 virtual std::string print_type(Type, AppendSpaceIfNeeded space_option = DoNotAppendSpace);
123
124 /** Emit a statement to reinterpret an expression as another type */
125 virtual std::string print_reinterpret(Type, const Expr &);
126
127 /** Emit a version of a string that is a valid identifier in C (. is replaced with _) */
128 virtual std::string print_name(const std::string &);
129
130 /** Add platform specific prologue */
131 virtual void add_platform_prologue();
132
133 /** Add typedefs for vector types. Not needed for OpenCL, might
134 * use different syntax for other C-like languages. */
135 virtual void add_vector_typedefs(const std::set<Type> &vector_types);
136
137 /** Bottleneck to allow customization of calls to generic Extern/PureExtern calls. */
138 virtual std::string print_extern_call(const Call *op);
139
140 /** Convert a vector Expr into a series of scalar Exprs, then reassemble into vector of original type. */
141 std::string print_scalarized_expr(const Expr &e);
142
143 /** Emit an SSA-style assignment, and set id to the freshly generated name. Return id. */
144 virtual std::string print_assignment(Type t, const std::string &rhs);
145
146 /** Emit free for the heap allocation. **/
147 void print_heap_free(const std::string &alloc_name);
148
149 /** Return true if only generating an interface, which may be extern "C" or C++ */
155
156 /** Return true if only generating an interface, which may be extern "C" or C++ */
161
162 /** Return true if only generating an interface, which may be extern "C" or C++ */
164 return is_header() || is_extern_decl();
165 }
166
167 /** Return true if generating C++ linkage. */
174
175 /** Open a new C scope (i.e. throw in a brace, increase the indent) */
177
178 /** Close a C scope (i.e. throw in an end brace, decrease the indent) */
179 void close_scope(const std::string &comment);
180
181 struct Allocation {
183 };
184
185 /** Track the types of allocations to avoid unnecessary casts. */
187
188 /** Track which allocations actually went on the heap. */
190
191 /** True if there is a void * __user_context parameter in the arguments. */
193
194 /** Track current calling convention scope. */
195 bool extern_c_open = false;
196
197 /** True if at least one gpu-based for loop is used. */
199
200 /** Track which handle types have been forward-declared already. */
201 std::set<const halide_handle_cplusplus_type *> forward_declared;
202
203 /** If the Type is a handle type, emit a forward-declaration for it
204 * if we haven't already. */
206
208
209 using IRPrinter::visit;
210
211 void visit(const Variable *) override;
212 void visit(const IntImm *) override;
213 void visit(const UIntImm *) override;
214 void visit(const StringImm *) override;
215 void visit(const FloatImm *) override;
216 void visit(const Cast *) override;
217 void visit(const Reinterpret *) override;
218 void visit(const Add *) override;
219 void visit(const Sub *) override;
220 void visit(const Mul *) override;
221 void visit(const Div *) override;
222 void visit(const Mod *) override;
223 void visit(const Max *) override;
224 void visit(const Min *) override;
225 void visit(const EQ *) override;
226 void visit(const NE *) override;
227 void visit(const LT *) override;
228 void visit(const LE *) override;
229 void visit(const GT *) override;
230 void visit(const GE *) override;
231 void visit(const And *) override;
232 void visit(const Or *) override;
233 void visit(const Not *) override;
234 void visit(const Call *) override;
235 void visit(const Select *) override;
236 void visit(const Load *) override;
237 void visit(const Store *) override;
238 void visit(const Let *) override;
239 void visit(const LetStmt *) override;
240 void visit(const AssertStmt *) override;
241 void visit(const ProducerConsumer *) override;
242 void visit(const For *) override;
243 void visit(const Ramp *) override;
244 void visit(const Broadcast *) override;
245 void visit(const Provide *) override;
246 void visit(const Allocate *) override;
247 void visit(const Free *) override;
248 void visit(const Realize *) override;
249 void visit(const IfThenElse *) override;
250 void visit(const Evaluate *) override;
251 void visit(const Shuffle *) override;
252 void visit(const Prefetch *) override;
253 void visit(const Fork *) override;
254 void visit(const Acquire *) override;
255 void visit(const Atomic *) override;
256 void visit(const VectorReduce *) override;
257
258 void visit_binop(Type t, const Expr &a, const Expr &b, const char *op);
259 void visit_relop(Type t, const Expr &a, const Expr &b, const char *scalar_op, const char *vector_op);
260
261 template<typename T>
262 static std::string with_sep(const std::vector<T> &v, const std::string &sep) {
263 std::ostringstream o;
264 for (size_t i = 0; i < v.size(); ++i) {
265 if (i > 0) {
266 o << sep;
267 }
268 o << v[i];
269 }
270 return o.str();
271 }
272
273 template<typename T>
274 static std::string with_commas(const std::vector<T> &v) {
275 return with_sep<T>(v, ", ");
276 }
277
278 /** Are we inside an atomic node that uses mutex locks?
279 This is used for detecting deadlocks from nested atomics. */
281
282 /** Emit atomic store instructions? */
283 bool emit_atomic_stores = false;
284
285 /** true if add_vector_typedefs() has been called. */
287
288 /** Some architectures have private memory for the call stack; this
289 * means a thread cannot hand pointers to stack memory to another
290 * thread. Returning true here flag forces heap allocation of
291 * things that might be shared, such as closures and any buffer
292 * that may be used in a parallel context. */
293 virtual bool is_stack_private_to_thread() const;
294
295 void emit_argv_wrapper(const std::string &function_name,
296 const std::vector<LoweredArgument> &args);
297 void emit_metadata_getter(const std::string &function_name,
298 const std::vector<LoweredArgument> &args,
299 const MetadataNameMap &metadata_name_map);
300 void emit_constexpr_function_info(const std::string &function_name,
301 const std::vector<LoweredArgument> &args,
302 const MetadataNameMap &metadata_name_map);
303 void emit_halide_free_helper(const std::string &alloc_name, const std::string &free_function);
304};
305
306} // namespace Internal
307} // namespace Halide
308
309#endif
This header file defines operators that let you dump a Halide expression, statement,...
Defines the Scope class, which is used for keeping track of names in a scope while traversing IR.
Defines the structure that describes a Halide target.
This class emits C++ code equivalent to a halide Stmt.
Definition CodeGen_C.h:27
void visit(const GE *) override
bool is_extern_decl()
Return true if only generating an interface, which may be extern "C" or C++.
Definition CodeGen_C.h:157
void visit(const Provide *) override
void visit(const Evaluate *) override
virtual std::string print_type(Type, AppendSpaceIfNeeded space_option=DoNotAppendSpace)
Emit the C name for a halide type.
void print_heap_free(const std::string &alloc_name)
Emit free for the heap allocation.
void visit(const NE *) override
void visit(const Realize *) override
CodeGen_C(std::ostream &dest, const Target &target, OutputKind output_kind=CImplementation, const std::string &include_guard="")
Initialize a C code generator pointing at a particular output stream (e.g.
void visit(const Call *) override
void visit(const UIntImm *) override
void close_scope(const std::string &comment)
Close a C scope (i.e.
void visit(const Or *) override
void visit(const Sub *) override
void create_assertion(const std::string &id_cond, const Expr &message)
void open_scope()
Open a new C scope (i.e.
virtual bool is_stack_private_to_thread() const
Some architectures have private memory for the call stack; this means a thread cannot hand pointers t...
OutputKind output_kind
Controls whether this instance is generating declarations or definitions and whether the interface us...
Definition CodeGen_C.h:93
bool is_header()
Return true if only generating an interface, which may be extern "C" or C++.
Definition CodeGen_C.h:150
bool using_vector_typedefs
true if add_vector_typedefs() has been called.
Definition CodeGen_C.h:286
void visit(const Max *) override
void visit(const Select *) override
void visit(const Load *) override
void visit(const FloatImm *) override
void forward_declare_type_if_needed(const Type &t)
If the Type is a handle type, emit a forward-declaration for it if we haven't already.
void visit(const LE *) override
void visit(const Div *) override
Expr scalarize_vector_reduce(const VectorReduce *op)
void visit(const Let *) override
void visit(const And *) override
void visit(const Atomic *) override
std::set< const halide_handle_cplusplus_type * > forward_declared
Track which handle types have been forward-declared already.
Definition CodeGen_C.h:201
bool is_header_or_extern_decl()
Return true if only generating an interface, which may be extern "C" or C++.
Definition CodeGen_C.h:163
virtual void add_vector_typedefs(const std::set< Type > &vector_types)
Add typedefs for vector types.
void visit(const For *) override
void print_stmt(const Stmt &)
Emit a statement.
void compile(const LoweredFunc &func, const MetadataNameMap &metadata_name_map)
Emit a declaration.
virtual Stmt preprocess_function_body(const Stmt &stmt)
This is a hook that subclasses can use to transform a function body just before it is emitted – e....
Scope< Allocation > allocations
Track the types of allocations to avoid unnecessary casts.
Definition CodeGen_C.h:186
virtual std::string print_name(const std::string &)
Emit a version of a string that is a valid identifier in C (.
void visit(const GT *) override
void visit(const Free *) override
void compile(const Buffer<> &buffer)
void visit(const Store *) override
bool emit_atomic_stores
Emit atomic store instructions?
Definition CodeGen_C.h:283
void emit_halide_free_helper(const std::string &alloc_name, const std::string &free_function)
void visit(const Prefetch *) override
void visit(const Add *) override
Scope heap_allocations
Track which allocations actually went on the heap.
Definition CodeGen_C.h:189
Target target
The target being generated for.
Definition CodeGen_C.h:89
virtual std::string print_extern_call(const Call *op)
Bottleneck to allow customization of calls to generic Extern/PureExtern calls.
virtual std::string print_reinterpret(Type, const Expr &)
Emit a statement to reinterpret an expression as another type.
void visit(const Reinterpret *) override
void visit(const AssertStmt *) override
void visit(const EQ *) override
const Target & get_target() const
The target we're generating code for.
Definition CodeGen_C.h:51
void create_assertion(const Expr &cond, const Expr &message)
void visit(const VectorReduce *) override
void visit(const Ramp *) override
void emit_argv_wrapper(const std::string &function_name, const std::vector< LoweredArgument > &args)
bool is_c_plus_plus_interface()
Return true if generating C++ linkage.
Definition CodeGen_C.h:168
void visit(const Not *) override
void emit_constexpr_function_info(const std::string &function_name, const std::vector< LoweredArgument > &args, const MetadataNameMap &metadata_name_map)
std::string id
An ID for the most recently generated ssa variable.
Definition CodeGen_C.h:86
void visit_relop(Type t, const Expr &a, const Expr &b, const char *scalar_op, const char *vector_op)
static std::string with_commas(const std::vector< T > &v)
Definition CodeGen_C.h:274
void visit(const Min *) override
void visit(const Variable *) override
void emit_metadata_getter(const std::string &function_name, const std::vector< LoweredArgument > &args, const MetadataNameMap &metadata_name_map)
void set_name_mangling_mode(NameMangling mode)
void visit(const Mul *) override
void visit(const Mod *) override
void visit(const Allocate *) override
bool have_user_context
True if there is a void * __user_context parameter in the arguments.
Definition CodeGen_C.h:192
static std::string with_sep(const std::vector< T > &v, const std::string &sep)
Definition CodeGen_C.h:262
void visit(const Cast *) override
virtual std::string print_assignment(Type t, const std::string &rhs)
Emit an SSA-style assignment, and set id to the freshly generated name.
bool extern_c_open
Track current calling convention scope.
Definition CodeGen_C.h:195
virtual void add_platform_prologue()
Add platform specific prologue.
bool inside_atomic_mutex_node
Are we inside an atomic node that uses mutex locks? This is used for detecting deadlocks from nested ...
Definition CodeGen_C.h:280
void visit(const IfThenElse *) override
void visit(const Broadcast *) override
void visit(const StringImm *) override
void compile(const Module &module)
Emit the declarations contained in the module as C code.
void visit(const Shuffle *) override
std::string print_expr(const Expr &)
Emit an expression as an assignment, then return the id of the resulting var.
void visit(const LT *) override
std::string print_scalarized_expr(const Expr &e)
Convert a vector Expr into a series of scalar Exprs, then reassemble into vector of original type.
void visit(const LetStmt *) override
bool uses_gpu_for_loops
True if at least one gpu-based for loop is used.
Definition CodeGen_C.h:198
void visit(const Fork *) override
void visit(const ProducerConsumer *) override
void visit(const Acquire *) override
std::map< std::string, std::string > cache
A cache of generated values in scope.
Definition CodeGen_C.h:96
IntegerSuffixStyle integer_suffix_style
How to emit 64-bit integer constants.
Definition CodeGen_C.h:65
void visit(const IntImm *) override
void visit_binop(Type t, const Expr &a, const Expr &b, const char *op)
std::string print_cast_expr(const Type &, const Expr &)
Like print_expr, but cast the Expr to the given Type.
An IRVisitor that emits IR to the given output stream in a human readable form.
Definition IRPrinter.h:122
void visit(const IntImm *) override
A common pattern when traversing Halide IR is that you need to keep track of stuff when you find a Le...
Definition Scope.h:94
A halide module.
Definition Module.h:142
This file defines the class FunctionDAG, which is our representation of a Halide pipeline,...
@ Internal
Not visible externally, similar to 'static' linkage in C.
NameMangling
An enum to specify calling convention for extern stages.
Definition Function.h:26
std::map< std::string, std::string > MetadataNameMap
Definition Module.h:138
A fragment of Halide syntax.
Definition Expr.h:258
The sum of two expressions.
Definition IR.h:56
Allocate a scratch area called with the given name, type, and size.
Definition IR.h:371
Logical and - are both expressions true.
Definition IR.h:175
If the 'condition' is false, then evaluate and return the message, which should be a call to an error...
Definition IR.h:294
Lock all the Store nodes in the body statement.
Definition IR.h:961
A vector with 'lanes' elements, in which every element is 'value'.
Definition IR.h:259
A function call.
Definition IR.h:490
The actual IR nodes begin here.
Definition IR.h:30
The ratio of two expressions.
Definition IR.h:83
Is the first expression equal to the second.
Definition IR.h:121
Evaluate and discard an expression, presumably because it has some side-effect.
Definition IR.h:476
Floating point constants.
Definition Expr.h:236
A for loop.
Definition IR.h:819
A pair of statements executed concurrently.
Definition IR.h:457
Free the resources associated with the given buffer.
Definition IR.h:413
Is the first expression greater than or equal to the second.
Definition IR.h:166
Is the first expression greater than the second.
Definition IR.h:157
An if-then-else block.
Definition IR.h:466
Integer constants.
Definition Expr.h:218
Is the first expression less than or equal to the second.
Definition IR.h:148
Is the first expression less than the second.
Definition IR.h:139
A let expression, like you might find in a functional language.
Definition IR.h:271
The statement form of a let node.
Definition IR.h:282
Load a value from a named symbol if predicate is true.
Definition IR.h:217
Definition of a lowered function.
Definition Module.h:101
The greater of two values.
Definition IR.h:112
The lesser of two values.
Definition IR.h:103
The remainder of a / b.
Definition IR.h:94
The product of two expressions.
Definition IR.h:74
Is the first expression not equal to the second.
Definition IR.h:130
Logical not - true if the expression false.
Definition IR.h:193
Logical or - is at least one of the expression true.
Definition IR.h:184
Represent a multi-dimensional region of a Func or an ImageParam that needs to be prefetched.
Definition IR.h:923
This node is a helpful annotation to do with permissions.
Definition IR.h:315
This defines the value of a function at a multi-dimensional location.
Definition IR.h:354
A linear ramp vector node.
Definition IR.h:247
Allocate a multi-dimensional buffer of the given type and size.
Definition IR.h:427
Reinterpret value as another type, without affecting any of the bits (on little-endian systems).
Definition IR.h:47
A ternary operator.
Definition IR.h:204
Construct a new vector by taking elements from another sequence of vectors.
Definition IR.h:855
A reference-counted handle to a statement node.
Definition Expr.h:427
Store a 'value' to the buffer called 'name' at a given 'index' if 'predicate' is true.
Definition IR.h:333
String constants.
Definition Expr.h:245
The difference of two expressions.
Definition IR.h:65
Unsigned integer constants.
Definition Expr.h:227
A named variable.
Definition IR.h:772
Horizontally reduce a vector to a scalar or narrower vector using the given commutative and associati...
Definition IR.h:979
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:283