1//===-- MyExtension.cpp - Transform dialect tutorial ----------------------===//
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 defines Transform dialect extension operations used in the
10// Chapter 3 of the Transform dialect tutorial.
11//
12//===----------------------------------------------------------------------===//
13
14#include "MyExtension.h"
15#include "mlir/Dialect/Func/IR/FuncOps.h"
16#include "mlir/Dialect/SCF/IR/SCF.h"
17#include "mlir/Dialect/Transform/IR/TransformDialect.h"
18#include "mlir/Dialect/Transform/IR/TransformTypes.h"
19#include "mlir/IR/DialectImplementation.h"
20#include "mlir/Interfaces/CallInterfaces.h"
21#include "llvm/ADT/TypeSwitch.h"
22
23#define GET_TYPEDEF_CLASSES
24#include "MyExtensionTypes.cpp.inc"
25
26#define GET_OP_CLASSES
27#include "MyExtension.cpp.inc"
28
29//===---------------------------------------------------------------------===//
30// MyExtension
31//===---------------------------------------------------------------------===//
32
33// Define a new transform dialect extension. This uses the CRTP idiom to
34// identify extensions.
35class MyExtension
36 : public ::mlir::transform::TransformDialectExtension<MyExtension> {
37public:
38 // The extension must derive the base constructor.
39 using Base::Base;
40
41 // This function initializes the extension, similarly to `initialize` in
42 // dialect definitions. List individual operations and dependent dialects
43 // here.
44 void init();
45};
46
47void MyExtension::init() {
48 // Similarly to dialects, an extension can declare a dependent dialect. This
49 // dialect will be loaded along with the extension and, therefore, along with
50 // the Transform dialect. Only declare as dependent the dialects that contain
51 // the attributes or types used by transform operations. Do NOT declare as
52 // dependent the dialects produced during the transformation.
53 // declareDependentDialect<MyDialect>();
54
55 // When transformations are applied, they may produce new operations from
56 // previously unloaded dialects. Typically, a pass would need to declare
57 // itself dependent on the dialects containing such new operations. To avoid
58 // confusion with the dialects the extension itself depends on, the Transform
59 // dialects differentiates between:
60 // - dependent dialects, which are used by the transform operations, and
61 // - generated dialects, which contain the entities (attributes, operations,
62 // types) that may be produced by applying the transformation even when
63 // not present in the original payload IR.
64 // In the following chapter, we will be add operations that generate function
65 // calls and structured control flow operations, so let's declare the
66 // corresponding dialects as generated.
67 declareGeneratedDialect<::mlir::scf::SCFDialect>();
68 declareGeneratedDialect<::mlir::func::FuncDialect>();
69
70 // Register the additional transform dialect types with the dialect. List all
71 // types generated from ODS.
72 registerTypes<
73#define GET_TYPEDEF_LIST
74#include "MyExtensionTypes.cpp.inc"
75 >();
76
77 // ODS generates these helpers for type printing and parsing, but the
78 // Transform dialect provides its own support for types supplied by the
79 // extension. Reference these functions to avoid a compiler warning.
80 (void)&generatedTypeParser;
81 (void)&generatedTypePrinter;
82
83 // Finally, we register the additional transform operations with the dialect.
84 // List all operations generated from ODS. This call will perform additional
85 // checks that the operations implement the transform and memory effect
86 // interfaces required by the dialect interpreter and assert if they do not.
87 registerTransformOps<
88#define GET_OP_LIST
89#include "MyExtension.cpp.inc"
90 >();
91}
92
93//===---------------------------------------------------------------------===//
94// ChangeCallTargetOp
95//===---------------------------------------------------------------------===//
96
97static void updateCallee(mlir::func::CallOp call, llvm::StringRef newTarget) {
98 call.setCallee(newTarget);
99}
100
101// Implementation of our transform dialect operation.
102// This operation returns a tri-state result that can be one of:
103// - success when the transformation succeeded;
104// - definite failure when the transformation failed in such a way that
105// following
106// transformations are impossible or undesirable, typically it could have left
107// payload IR in an invalid state; it is expected that a diagnostic is emitted
108// immediately before returning the definite error;
109// - silenceable failure when the transformation failed but following
110// transformations
111// are still applicable, typically this means a precondition for the
112// transformation is not satisfied and the payload IR has not been modified.
113// The silenceable failure additionally carries a Diagnostic that can be emitted
114// to the user.
115::mlir::DiagnosedSilenceableFailure
116mlir::transform::ChangeCallTargetOp::applyToOne(
117 // The rewriter that should be used when modifying IR.
118 ::mlir::transform::TransformRewriter &rewriter,
119 // The single payload operation to which the transformation is applied.
120 ::mlir::func::CallOp call,
121 // The payload IR entities that will be appended to lists associated with
122 // the results of this transform operation. This list contains one entry per
123 // result.
124 ::mlir::transform::ApplyToEachResultList &results,
125 // The transform application state. This object can be used to query the
126 // current associations between transform IR values and payload IR entities.
127 // It can also carry additional user-defined state.
128 ::mlir::transform::TransformState &state) {
129
130 // Dispatch to the actual transformation.
131 updateCallee(call, getNewTarget());
132
133 // If everything went well, return success.
134 return DiagnosedSilenceableFailure::success();
135}
136
137void mlir::transform::ChangeCallTargetOp::getEffects(
138 ::llvm::SmallVectorImpl<::mlir::MemoryEffects::EffectInstance> &effects) {
139 // Indicate that the `call` handle is only read by this operation because the
140 // associated operation is not erased but rather modified in-place, so the
141 // reference to it remains valid.
142 onlyReadsHandle(getCall(), effects);
143
144 // Indicate that the payload is modified by this operation.
145 modifiesPayload(effects);
146}
147
148//===---------------------------------------------------------------------===//
149// CallToOp
150//===---------------------------------------------------------------------===//
151
152static mlir::Operation *replaceCallWithOp(mlir::RewriterBase &rewriter,
153 mlir::CallOpInterface call) {
154 // Construct an operation from an unregistered dialect. This is discouraged
155 // and is only used here for brevity of the overall example.
156 mlir::OperationState state(call.getLoc(), "my.mm4");
157 state.types.assign(call->result_type_begin(), call->result_type_end());
158 state.operands.assign(call->operand_begin(), call->operand_end());
159
160 mlir::Operation *replacement = rewriter.create(state);
161 rewriter.replaceOp(call, replacement->getResults());
162 return replacement;
163}
164
165// See above for the signature description.
166mlir::DiagnosedSilenceableFailure mlir::transform::CallToOp::applyToOne(
167 mlir::transform::TransformRewriter &rewriter, mlir::CallOpInterface call,
168 mlir::transform::ApplyToEachResultList &results,
169 mlir::transform::TransformState &state) {
170
171 // Dispatch to the actual transformation.
172 Operation *replacement = replaceCallWithOp(rewriter, call);
173
174 // Associate the payload operation produced by the rewrite with the result
175 // handle of this transform operation.
176 results.push_back(replacement);
177
178 // If everything went well, return success.
179 return DiagnosedSilenceableFailure::success();
180}
181
182//===---------------------------------------------------------------------===//
183// CallOpInterfaceHandleType
184//===---------------------------------------------------------------------===//
185
186// The interface declares this method to verify constraints this type has on
187// payload operations. It returns the now familiar tri-state result.
188mlir::DiagnosedSilenceableFailure
189mlir::transform::CallOpInterfaceHandleType::checkPayload(
190 // Location at which diagnostics should be emitted.
191 mlir::Location loc,
192 // List of payload operations that are about to be associated with the
193 // handle that has this type.
194 llvm::ArrayRef<mlir::Operation *> payload) const {
195
196 // All payload operations are expected to implement CallOpInterface, check
197 // this.
198 for (Operation *op : payload) {
199 if (llvm::isa<mlir::CallOpInterface>(op))
200 continue;
201
202 // By convention, these verifiers always emit a silenceable failure since
203 // they are checking a precondition.
204 DiagnosedSilenceableFailure diag =
205 emitSilenceableError(loc)
206 << "expected the payload operation to implement CallOpInterface";
207 diag.attachNote(op->getLoc()) << "offending operation";
208 return diag;
209 }
210
211 // If everything is okay, return success.
212 return DiagnosedSilenceableFailure::success();
213}
214
215//===---------------------------------------------------------------------===//
216// Extension registration
217//===---------------------------------------------------------------------===//
218
219void registerMyExtension(::mlir::DialectRegistry &registry) {
220 registry.addExtensions<MyExtension>();
221}
222

source code of mlir/examples/transform/Ch3/lib/MyExtension.cpp