Halide 21.0.0
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
13#include <unordered_map>
14
15namespace Halide {
16
17struct Argument;
18class Module;
19
20namespace Internal {
21
22struct LoweredFunc;
23
24/** This class emits C++ code equivalent to a halide Stmt. It's
25 * mostly the same as an IRPrinter, but it's wrapped in a function
26 * definition, and some things are handled differently to be valid
27 * C++.
28 */
29class CodeGen_C : public IRPrinter {
30public:
40
41 /** Initialize a C code generator pointing at a particular output
42 * stream (e.g. a file, or std::cout) */
43 CodeGen_C(std::ostream &dest,
44 const Target &target,
46 const std::string &include_guard = "");
47 ~CodeGen_C() override;
48
49 /** Emit the declarations contained in the module as C code. */
50 void compile(const Module &module);
51
52 /** The target we're generating code for */
53 const Target &get_target() const {
54 return target;
55 }
56
57 static void test();
58
59protected:
60 enum class IntegerSuffixStyle {
61 PlainC = 0,
62 OpenCL = 1,
63 HLSL = 2
64 };
65
66 /** How to emit 64-bit integer constants */
68
69 /** Emit a declaration. */
70 // @{
71 void compile(const LoweredFunc &func, const MetadataNameMap &metadata_name_map);
72 void compile(const Buffer<> &buffer);
73 // @}
74
75 /** This is a hook that subclasses can use to transform a function body
76 * just before it is emitted -- e.g., to transform the IR to code that
77 * is easier to recognize and emit. The default implementation simply
78 * returns the input unchanged.
79 *
80 * This hook will always be called after the function declaration and
81 * opening brace is emitted, so in addition to (possibly) returning
82 * a modified Stmt, this function may also emit C++ code to the default
83 * stream if it wishes to add some prologue at the start of the function.
84 */
86
87 /** An ID for the most recently generated ssa variable */
88 std::string id;
89
90 /** The target being generated for. */
92
93 /** Controls whether this instance is generating declarations or
94 * definitions and whether the interface us extern "C" or C++. */
96
97 /** A cache of generated values in scope */
98 std::map<std::string, std::string> cache;
99
100 /** Emit an expression as an assignment, then return the id of the
101 * resulting var */
102 std::string print_expr(const Expr &);
103
104 /** Like print_expr, but cast the Expr to the given Type */
105 std::string print_cast_expr(const Type &, const Expr &);
106
107 /** Emit a statement */
108 void print_stmt(const Stmt &);
109
110 void create_assertion(const std::string &id_cond, const Expr &message);
111 void create_assertion(const Expr &cond, const Expr &message);
112
118
119 /** Emit the C name for a halide type. If space_option is AppendSpace,
120 * and there should be a space between the type and the next token,
121 * one is appended. (This allows both "int foo" and "Foo *foo" to be
122 * formatted correctly. Otherwise the latter is "Foo * foo".)
123 */
124 virtual std::string print_type(Type, AppendSpaceIfNeeded space_option = DoNotAppendSpace);
125
126 /** Emit a statement to reinterpret an expression as another type */
127 virtual std::string print_reinterpret(Type, const Expr &);
128
129 /** Emit a version of a string that is a valid identifier in C (. is replaced with _) */
130 virtual std::string print_name(const std::string &);
131
132 /** Add platform specific prologue */
133 virtual void add_platform_prologue();
134
135 /** Add typedefs for vector types. Not needed for OpenCL, might
136 * use different syntax for other C-like languages. */
137 virtual void add_vector_typedefs(const std::set<Type> &vector_types);
138
139 std::unordered_map<std::string, std::string> extern_function_name_map;
140
141 /** Bottleneck to allow customization of calls to generic Extern/PureExtern calls. */
142 virtual std::string print_extern_call(const Call *op);
143
144 /** Convert a vector Expr into a series of scalar Exprs, then reassemble into vector of original type. */
145 std::string print_scalarized_expr(const Expr &e);
146
147 /** Emit an SSA-style assignment, and set id to the freshly generated name. Return id. */
148 virtual std::string print_assignment(Type t, const std::string &rhs);
149
150 /** Emit free for the heap allocation. **/
151 void print_heap_free(const std::string &alloc_name);
152
153 /** Return true if only generating an interface, which may be extern "C" or C++ */
159
160 /** Return true if only generating an interface, which may be extern "C" or C++ */
165
166 /** Return true if only generating an interface, which may be extern "C" or C++ */
168 return is_header() || is_extern_decl();
169 }
170
171 /** Return true if generating C++ linkage. */
178
179 /** Open a new C scope (i.e. throw in a brace, increase the indent) */
181
182 /** Close a C scope (i.e. throw in an end brace, decrease the indent) */
183 void close_scope(const std::string &comment);
184
185 struct Allocation {
187 };
188
189 /** Track the types of allocations to avoid unnecessary casts. */
191
192 /** Track which allocations actually went on the heap. */
194
195 /** True if there is a void * __user_context parameter in the arguments. */
197
198 /** Track current calling convention scope. */
199 bool extern_c_open = false;
200
201 /** True if at least one gpu-based for loop is used. */
203
204 /** Track which handle types have been forward-declared already. */
205 std::set<const halide_handle_cplusplus_type *> forward_declared;
206
207 /** If the Type is a handle type, emit a forward-declaration for it
208 * if we haven't already. */
210
212
213 using IRPrinter::visit;
214
215 void visit(const Variable *) override;
216 void visit(const IntImm *) override;
217 void visit(const UIntImm *) override;
218 void visit(const StringImm *) override;
219 void visit(const FloatImm *) override;
220 void visit(const Cast *) override;
221 void visit(const Reinterpret *) override;
222 void visit(const Add *) override;
223 void visit(const Sub *) override;
224 void visit(const Mul *) override;
225 void visit(const Div *) override;
226 void visit(const Mod *) override;
227 void visit(const Max *) override;
228 void visit(const Min *) override;
229 void visit(const EQ *) override;
230 void visit(const NE *) override;
231 void visit(const LT *) override;
232 void visit(const LE *) override;
233 void visit(const GT *) override;
234 void visit(const GE *) override;
235 void visit(const And *) override;
236 void visit(const Or *) override;
237 void visit(const Not *) override;
238 void visit(const Call *) override;
239 void visit(const Select *) override;
240 void visit(const Load *) override;
241 void visit(const Store *) override;
242 void visit(const Let *) override;
243 void visit(const LetStmt *) override;
244 void visit(const AssertStmt *) override;
245 void visit(const ProducerConsumer *) override;
246 void visit(const For *) override;
247 void visit(const Ramp *) override;
248 void visit(const Broadcast *) override;
249 void visit(const Provide *) override;
250 void visit(const Allocate *) override;
251 void visit(const Free *) override;
252 void visit(const Realize *) override;
253 void visit(const IfThenElse *) override;
254 void visit(const Evaluate *) override;
255 void visit(const Shuffle *) override;
256 void visit(const Prefetch *) override;
257 void visit(const Fork *) override;
258 void visit(const Acquire *) override;
259 void visit(const Atomic *) override;
260 void visit(const VectorReduce *) override;
261
262 void visit_binop(Type t, const Expr &a, const Expr &b, const char *op);
263 void visit_relop(Type t, const Expr &a, const Expr &b, const char *scalar_op, const char *vector_op);
264
265 template<typename T>
266 static std::string with_sep(const std::vector<T> &v, const std::string &sep) {
267 std::ostringstream o;
268 for (size_t i = 0; i < v.size(); ++i) {
269 if (i > 0) {
270 o << sep;
271 }
272 o << v[i];
273 }
274 return o.str();
275 }
276
277 template<typename T>
278 static std::string with_commas(const std::vector<T> &v) {
279 return with_sep<T>(v, ", ");
280 }
281
282 /** Are we inside an atomic node that uses mutex locks?
283 This is used for detecting deadlocks from nested atomics. */
285
286 /** Emit atomic store instructions? */
287 bool emit_atomic_stores = false;
288
289 /** true if add_vector_typedefs() has been called. */
291
292 /** Some architectures have private memory for the call stack; this
293 * means a thread cannot hand pointers to stack memory to another
294 * thread. Returning true here flag forces heap allocation of
295 * things that might be shared, such as closures and any buffer
296 * that may be used in a parallel context. */
297 virtual bool is_stack_private_to_thread() const;
298
299 void emit_argv_wrapper(const std::string &function_name,
300 const std::vector<LoweredArgument> &args);
301 void emit_metadata_getter(const std::string &function_name,
302 const std::vector<LoweredArgument> &args,
303 const MetadataNameMap &metadata_name_map);
304 void emit_constexpr_function_info(const std::string &function_name,
305 const std::vector<LoweredArgument> &args,
306 const MetadataNameMap &metadata_name_map);
307 void emit_halide_free_helper(const std::string &alloc_name, const std::string &free_function);
308};
309
310} // namespace Internal
311} // namespace Halide
312
313#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.
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:161
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:95
bool is_header()
Return true if only generating an interface, which may be extern "C" or C++.
Definition CodeGen_C.h:154
bool using_vector_typedefs
true if add_vector_typedefs() has been called.
Definition CodeGen_C.h:290
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:205
bool is_header_or_extern_decl()
Return true if only generating an interface, which may be extern "C" or C++.
Definition CodeGen_C.h:167
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:190
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:287
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:193
Target target
The target being generated for.
Definition CodeGen_C.h:91
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:53
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:172
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:88
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:278
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:196
static std::string with_sep(const std::vector< T > &v, const std::string &sep)
Definition CodeGen_C.h:266
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:199
virtual void add_platform_prologue()
Add platform specific prologue.
bool inside_atomic_mutex_node
Are we inside an atomic node that uses mutex locks?
Definition CodeGen_C.h:284
void visit(const IfThenElse *) override
std::unordered_map< std::string, std::string > extern_function_name_map
Definition CodeGen_C.h:139
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:202
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:98
IntegerSuffixStyle integer_suffix_style
How to emit 64-bit integer constants.
Definition CodeGen_C.h:67
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.
void visit(const IntImm *) override
IRPrinter(std::ostream &)
Construct an IRPrinter pointed at a given output stream (e.g.
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,...
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 struct representing an argument to a halide-generated function.
Definition Argument.h:37
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:994
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:848
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:956
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:884
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:801
Horizontally reduce a vector to a scalar or narrower vector using the given commutative and associati...
Definition IR.h:1012
A struct representing a target machine and os to generate code for.
Definition Target.h:19