1//===- Serializer.h - MLIR SPIR-V Serializer ------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file declares the MLIR SPIR-V module to SPIR-V binary serializer.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef MLIR_LIB_TARGET_SPIRV_SERIALIZATION_SERIALIZER_H
14#define MLIR_LIB_TARGET_SPIRV_SERIALIZATION_SERIALIZER_H
15
16#include "mlir/Dialect/SPIRV/IR/SPIRVOps.h"
17#include "mlir/IR/Builders.h"
18#include "mlir/Target/SPIRV/Serialization.h"
19#include "llvm/ADT/SetVector.h"
20#include "llvm/ADT/SmallVector.h"
21#include "llvm/Support/raw_ostream.h"
22
23namespace mlir {
24namespace spirv {
25
26void encodeInstructionInto(SmallVectorImpl<uint32_t> &binary, spirv::Opcode op,
27 ArrayRef<uint32_t> operands);
28
29/// A SPIR-V module serializer.
30///
31/// A SPIR-V binary module is a single linear stream of instructions; each
32/// instruction is composed of 32-bit words with the layout:
33///
34/// | <word-count>|<opcode> | <operand> | <operand> | ... |
35/// | <------ word -------> | <-- word --> | <-- word --> | ... |
36///
37/// For the first word, the 16 high-order bits are the word count of the
38/// instruction, the 16 low-order bits are the opcode enumerant. The
39/// instructions then belong to different sections, which must be laid out in
40/// the particular order as specified in "2.4 Logical Layout of a Module" of
41/// the SPIR-V spec.
42class Serializer {
43public:
44 /// Creates a serializer for the given SPIR-V `module`.
45 explicit Serializer(spirv::ModuleOp module,
46 const SerializationOptions &options);
47
48 /// Serializes the remembered SPIR-V module.
49 LogicalResult serialize();
50
51 /// Collects the final SPIR-V `binary`.
52 void collect(SmallVectorImpl<uint32_t> &binary);
53
54#ifndef NDEBUG
55 /// (For debugging) prints each value and its corresponding result <id>.
56 void printValueIDMap(raw_ostream &os);
57#endif
58
59private:
60 // Note that there are two main categories of methods in this class:
61 // * process*() methods are meant to fully serialize a SPIR-V module entity
62 // (header, type, op, etc.). They update internal vectors containing
63 // different binary sections. They are not meant to be called except the
64 // top-level serialization loop.
65 // * prepare*() methods are meant to be helpers that prepare for serializing
66 // certain entity. They may or may not update internal vectors containing
67 // different binary sections. They are meant to be called among themselves
68 // or by other process*() methods for subtasks.
69
70 //===--------------------------------------------------------------------===//
71 // <id>
72 //===--------------------------------------------------------------------===//
73
74 // Note that it is illegal to use id <0> in SPIR-V binary module. Various
75 // methods in this class, if using SPIR-V word (uint32_t) as interface,
76 // check or return id <0> to indicate error in processing.
77
78 /// Consumes the next unused <id>. This method will never return 0.
79 uint32_t getNextID() { return nextID++; }
80
81 //===--------------------------------------------------------------------===//
82 // Module structure
83 //===--------------------------------------------------------------------===//
84
85 uint32_t getSpecConstID(StringRef constName) const {
86 return specConstIDMap.lookup(Key: constName);
87 }
88
89 uint32_t getVariableID(StringRef varName) const {
90 return globalVarIDMap.lookup(Key: varName);
91 }
92
93 uint32_t getFunctionID(StringRef fnName) const {
94 return funcIDMap.lookup(Key: fnName);
95 }
96
97 /// Gets the <id> for the function with the given name. Assigns the next
98 /// available <id> if the function haven't been deserialized.
99 uint32_t getOrCreateFunctionID(StringRef fnName);
100
101 void processCapability();
102
103 void processDebugInfo();
104
105 void processExtension();
106
107 void processMemoryModel();
108
109 LogicalResult processConstantOp(spirv::ConstantOp op);
110
111 LogicalResult processSpecConstantOp(spirv::SpecConstantOp op);
112
113 LogicalResult
114 processSpecConstantCompositeOp(spirv::SpecConstantCompositeOp op);
115
116 LogicalResult
117 processSpecConstantOperationOp(spirv::SpecConstantOperationOp op);
118
119 /// SPIR-V dialect supports OpUndef using spirv.UndefOp that produces a SSA
120 /// value to use with other operations. The SPIR-V spec recommends that
121 /// OpUndef be generated at module level. The serialization generates an
122 /// OpUndef for each type needed at module level.
123 LogicalResult processUndefOp(spirv::UndefOp op);
124
125 /// Emit OpName for the given `resultID`.
126 LogicalResult processName(uint32_t resultID, StringRef name);
127
128 /// Processes a SPIR-V function op.
129 LogicalResult processFuncOp(spirv::FuncOp op);
130 LogicalResult processFuncParameter(spirv::FuncOp op);
131
132 LogicalResult processVariableOp(spirv::VariableOp op);
133
134 /// Process a SPIR-V GlobalVariableOp
135 LogicalResult processGlobalVariableOp(spirv::GlobalVariableOp varOp);
136
137 /// Process attributes that translate to decorations on the result <id>
138 LogicalResult processDecorationAttr(Location loc, uint32_t resultID,
139 Decoration decoration, Attribute attr);
140 LogicalResult processDecoration(Location loc, uint32_t resultID,
141 NamedAttribute attr);
142
143 template <typename DType>
144 LogicalResult processTypeDecoration(Location loc, DType type,
145 uint32_t resultId) {
146 return emitError(loc, message: "unhandled decoration for type:") << type;
147 }
148
149 /// Process member decoration
150 LogicalResult processMemberDecoration(
151 uint32_t structID,
152 const spirv::StructType::MemberDecorationInfo &memberDecorationInfo);
153
154 //===--------------------------------------------------------------------===//
155 // Types
156 //===--------------------------------------------------------------------===//
157
158 uint32_t getTypeID(Type type) const { return typeIDMap.lookup(Val: type); }
159
160 Type getVoidType() { return mlirBuilder.getNoneType(); }
161
162 bool isVoidType(Type type) const { return isa<NoneType>(Val: type); }
163
164 /// Returns true if the given type is a pointer type to a struct in some
165 /// interface storage class.
166 bool isInterfaceStructPtrType(Type type) const;
167
168 /// Main dispatch method for serializing a type. The result <id> of the
169 /// serialized type will be returned as `typeID`.
170 LogicalResult processType(Location loc, Type type, uint32_t &typeID);
171 LogicalResult processTypeImpl(Location loc, Type type, uint32_t &typeID,
172 SetVector<StringRef> &serializationCtx);
173
174 /// Method for preparing basic SPIR-V type serialization. Returns the type's
175 /// opcode and operands for the instruction via `typeEnum` and `operands`.
176 LogicalResult prepareBasicType(Location loc, Type type, uint32_t resultID,
177 spirv::Opcode &typeEnum,
178 SmallVectorImpl<uint32_t> &operands,
179 bool &deferSerialization,
180 SetVector<StringRef> &serializationCtx);
181
182 LogicalResult prepareFunctionType(Location loc, FunctionType type,
183 spirv::Opcode &typeEnum,
184 SmallVectorImpl<uint32_t> &operands);
185
186 //===--------------------------------------------------------------------===//
187 // Constant
188 //===--------------------------------------------------------------------===//
189
190 uint32_t getConstantID(Attribute value) const {
191 return constIDMap.lookup(Val: value);
192 }
193
194 /// Main dispatch method for processing a constant with the given `constType`
195 /// and `valueAttr`. `constType` is needed here because we can interpret the
196 /// `valueAttr` as a different type than the type of `valueAttr` itself; for
197 /// example, ArrayAttr, whose type is NoneType, is used for spirv::ArrayType
198 /// constants.
199 uint32_t prepareConstant(Location loc, Type constType, Attribute valueAttr);
200
201 /// Prepares array attribute serialization. This method emits corresponding
202 /// OpConstant* and returns the result <id> associated with it. Returns 0 if
203 /// failed.
204 uint32_t prepareArrayConstant(Location loc, Type constType, ArrayAttr attr);
205
206 /// Prepares bool/int/float DenseElementsAttr serialization. This method
207 /// iterates the DenseElementsAttr to construct the constant array, and
208 /// returns the result <id> associated with it. Returns 0 if failed. Note
209 /// that the size of `index` must match the rank.
210 /// TODO: Consider to enhance splat elements cases. For splat cases,
211 /// we don't need to loop over all elements, especially when the splat value
212 /// is zero. We can use OpConstantNull when the value is zero.
213 uint32_t prepareDenseElementsConstant(Location loc, Type constType,
214 DenseElementsAttr valueAttr, int dim,
215 MutableArrayRef<uint64_t> index);
216
217 /// Prepares scalar attribute serialization. This method emits corresponding
218 /// OpConstant* and returns the result <id> associated with it. Returns 0 if
219 /// the attribute is not for a scalar bool/integer/float value. If `isSpec` is
220 /// true, then the constant will be serialized as a specialization constant.
221 uint32_t prepareConstantScalar(Location loc, Attribute valueAttr,
222 bool isSpec = false);
223
224 uint32_t prepareConstantBool(Location loc, BoolAttr boolAttr,
225 bool isSpec = false);
226
227 uint32_t prepareConstantInt(Location loc, IntegerAttr intAttr,
228 bool isSpec = false);
229
230 uint32_t prepareConstantFp(Location loc, FloatAttr floatAttr,
231 bool isSpec = false);
232
233 //===--------------------------------------------------------------------===//
234 // Control flow
235 //===--------------------------------------------------------------------===//
236
237 /// Returns the result <id> for the given block.
238 uint32_t getBlockID(Block *block) const { return blockIDMap.lookup(Val: block); }
239
240 /// Returns the result <id> for the given block. If no <id> has been assigned,
241 /// assigns the next available <id>
242 uint32_t getOrCreateBlockID(Block *block);
243
244#ifndef NDEBUG
245 /// (For debugging) prints the block with its result <id>.
246 void printBlock(Block *block, raw_ostream &os);
247#endif
248
249 /// Processes the given `block` and emits SPIR-V instructions for all ops
250 /// inside. Does not emit OpLabel for this block if `omitLabel` is true.
251 /// `emitMerge` is a callback that will be invoked before handling the
252 /// terminator op to inject the Op*Merge instruction if this is a SPIR-V
253 /// selection/loop header block.
254 LogicalResult processBlock(Block *block, bool omitLabel = false,
255 function_ref<LogicalResult()> emitMerge = nullptr);
256
257 /// Emits OpPhi instructions for the given block if it has block arguments.
258 LogicalResult emitPhiForBlockArguments(Block *block);
259
260 LogicalResult processSelectionOp(spirv::SelectionOp selectionOp);
261
262 LogicalResult processLoopOp(spirv::LoopOp loopOp);
263
264 LogicalResult processBranchConditionalOp(spirv::BranchConditionalOp);
265
266 LogicalResult processBranchOp(spirv::BranchOp branchOp);
267
268 //===--------------------------------------------------------------------===//
269 // Operations
270 //===--------------------------------------------------------------------===//
271
272 LogicalResult encodeExtensionInstruction(Operation *op,
273 StringRef extensionSetName,
274 uint32_t opcode,
275 ArrayRef<uint32_t> operands);
276
277 uint32_t getValueID(Value val) const { return valueIDMap.lookup(Val: val); }
278
279 LogicalResult processAddressOfOp(spirv::AddressOfOp addressOfOp);
280
281 LogicalResult processReferenceOfOp(spirv::ReferenceOfOp referenceOfOp);
282
283 /// Main dispatch method for serializing an operation.
284 LogicalResult processOperation(Operation *op);
285
286 /// Serializes an operation `op` as core instruction with `opcode` if
287 /// `extInstSet` is empty. Otherwise serializes it as an extended instruction
288 /// with `opcode` from `extInstSet`.
289 /// This method is a generic one for dispatching any SPIR-V ops that has no
290 /// variadic operands and attributes in TableGen definitions.
291 LogicalResult processOpWithoutGrammarAttr(Operation *op, StringRef extInstSet,
292 uint32_t opcode);
293
294 /// Dispatches to the serialization function for an operation in SPIR-V
295 /// dialect that is a mirror of an instruction in the SPIR-V spec. This is
296 /// auto-generated from ODS. Dispatch is handled for all operations in SPIR-V
297 /// dialect that have hasOpcode == 1.
298 LogicalResult dispatchToAutogenSerialization(Operation *op);
299
300 /// Serializes an operation in the SPIR-V dialect that is a mirror of an
301 /// instruction in the SPIR-V spec. This is auto generated if hasOpcode == 1
302 /// and autogenSerialization == 1 in ODS.
303 template <typename OpTy>
304 LogicalResult processOp(OpTy op) {
305 return op.emitError("unsupported op serialization");
306 }
307
308 //===--------------------------------------------------------------------===//
309 // Utilities
310 //===--------------------------------------------------------------------===//
311
312 /// Emits an OpDecorate instruction to decorate the given `target` with the
313 /// given `decoration`.
314 LogicalResult emitDecoration(uint32_t target, spirv::Decoration decoration,
315 ArrayRef<uint32_t> params = {});
316
317 /// Emits an OpLine instruction with the given `loc` location information into
318 /// the given `binary` vector.
319 LogicalResult emitDebugLine(SmallVectorImpl<uint32_t> &binary, Location loc);
320
321private:
322 /// The SPIR-V module to be serialized.
323 spirv::ModuleOp module;
324
325 /// An MLIR builder for getting MLIR constructs.
326 mlir::Builder mlirBuilder;
327
328 /// Serialization options.
329 SerializationOptions options;
330
331 /// A flag which indicates if the last processed instruction was a merge
332 /// instruction.
333 /// According to SPIR-V spec: "If a branch merge instruction is used, the last
334 /// OpLine in the block must be before its merge instruction".
335 bool lastProcessedWasMergeInst = false;
336
337 /// The <id> of the OpString instruction, which specifies a file name, for
338 /// use by other debug instructions.
339 uint32_t fileID = 0;
340
341 /// The next available result <id>.
342 uint32_t nextID = 1;
343
344 // The following are for different SPIR-V instruction sections. They follow
345 // the logical layout of a SPIR-V module.
346
347 SmallVector<uint32_t, 4> capabilities;
348 SmallVector<uint32_t, 0> extensions;
349 SmallVector<uint32_t, 0> extendedSets;
350 SmallVector<uint32_t, 3> memoryModel;
351 SmallVector<uint32_t, 0> entryPoints;
352 SmallVector<uint32_t, 4> executionModes;
353 SmallVector<uint32_t, 0> debug;
354 SmallVector<uint32_t, 0> names;
355 SmallVector<uint32_t, 0> decorations;
356 SmallVector<uint32_t, 0> typesGlobalValues;
357 SmallVector<uint32_t, 0> functions;
358
359 /// Recursive struct references are serialized as OpTypePointer instructions
360 /// to the recursive struct type. However, the OpTypePointer instruction
361 /// cannot be emitted before the recursive struct's OpTypeStruct.
362 /// RecursiveStructPointerInfo stores the data needed to emit such
363 /// OpTypePointer instructions after forward references to such types.
364 struct RecursiveStructPointerInfo {
365 uint32_t pointerTypeID;
366 spirv::StorageClass storageClass;
367 };
368
369 // Maps spirv::StructType to its recursive reference member info.
370 DenseMap<Type, SmallVector<RecursiveStructPointerInfo, 0>>
371 recursiveStructInfos;
372
373 /// `functionHeader` contains all the instructions that must be in the first
374 /// block in the function, and `functionBody` contains the rest. After
375 /// processing FuncOp, the encoded instructions of a function are appended to
376 /// `functions`. An example of instructions in `functionHeader` in order:
377 /// OpFunction ...
378 /// OpFunctionParameter ...
379 /// OpFunctionParameter ...
380 /// OpLabel ...
381 /// OpVariable ...
382 /// OpVariable ...
383 SmallVector<uint32_t, 0> functionHeader;
384 SmallVector<uint32_t, 0> functionBody;
385
386 /// Map from type used in SPIR-V module to their <id>s.
387 DenseMap<Type, uint32_t> typeIDMap;
388
389 /// Map from constant values to their <id>s.
390 DenseMap<Attribute, uint32_t> constIDMap;
391
392 /// Map from specialization constant names to their <id>s.
393 llvm::StringMap<uint32_t> specConstIDMap;
394
395 /// Map from GlobalVariableOps name to <id>s.
396 llvm::StringMap<uint32_t> globalVarIDMap;
397
398 /// Map from FuncOps name to <id>s.
399 llvm::StringMap<uint32_t> funcIDMap;
400
401 /// Map from blocks to their <id>s.
402 DenseMap<Block *, uint32_t> blockIDMap;
403
404 /// Map from the Type to the <id> that represents undef value of that type.
405 DenseMap<Type, uint32_t> undefValIDMap;
406
407 /// Map from results of normal operations to their <id>s.
408 DenseMap<Value, uint32_t> valueIDMap;
409
410 /// Map from extended instruction set name to <id>s.
411 llvm::StringMap<uint32_t> extendedInstSetIDMap;
412
413 /// Map from values used in OpPhi instructions to their offset in the
414 /// `functions` section.
415 ///
416 /// When processing a block with arguments, we need to emit OpPhi
417 /// instructions to record the predecessor block <id>s and the values they
418 /// send to the block in question. But it's not guaranteed all values are
419 /// visited and thus assigned result <id>s. So we need this list to capture
420 /// the offsets into `functions` where a value is used so that we can fix it
421 /// up later after processing all the blocks in a function.
422 ///
423 /// More concretely, say if we are visiting the following blocks:
424 ///
425 /// ```mlir
426 /// ^phi(%arg0: i32):
427 /// ...
428 /// ^parent1:
429 /// ...
430 /// spirv.Branch ^phi(%val0: i32)
431 /// ^parent2:
432 /// ...
433 /// spirv.Branch ^phi(%val1: i32)
434 /// ```
435 ///
436 /// When we are serializing the `^phi` block, we need to emit at the beginning
437 /// of the block OpPhi instructions which has the following parameters:
438 ///
439 /// OpPhi id-for-i32 id-for-%arg0 id-for-%val0 id-for-^parent1
440 /// id-for-%val1 id-for-^parent2
441 ///
442 /// But we don't know the <id> for %val0 and %val1 yet. One way is to visit
443 /// all the blocks twice and use the first visit to assign an <id> to each
444 /// value. But it's paying the overheads just for OpPhi emission. Instead,
445 /// we still visit the blocks once for emission. When we emit the OpPhi
446 /// instructions, we use 0 as a placeholder for the <id>s for %val0 and %val1.
447 /// At the same time, we record their offsets in the emitted binary (which is
448 /// placed inside `functions`) here. And then after emitting all blocks, we
449 /// replace the dummy <id> 0 with the real result <id> by overwriting
450 /// `functions[offset]`.
451 DenseMap<Value, SmallVector<size_t, 1>> deferredPhiValues;
452};
453} // namespace spirv
454} // namespace mlir
455
456#endif // MLIR_LIB_TARGET_SPIRV_SERIALIZATION_SERIALIZER_H
457

source code of mlir/lib/Target/SPIRV/Serialization/Serializer.h