1//===---- CGLoopInfo.h - LLVM CodeGen for loop metadata -*- C++ -*---------===//
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 is the internal state used for llvm translation for loop statement
10// metadata.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_LIB_CODEGEN_CGLOOPINFO_H
15#define LLVM_CLANG_LIB_CODEGEN_CGLOOPINFO_H
16
17#include "llvm/ADT/ArrayRef.h"
18#include "llvm/ADT/SmallVector.h"
19#include "llvm/IR/DebugLoc.h"
20#include "llvm/IR/Value.h"
21#include "llvm/Support/Compiler.h"
22
23namespace llvm {
24class BasicBlock;
25class Instruction;
26class MDNode;
27} // end namespace llvm
28
29namespace clang {
30class Attr;
31class ASTContext;
32class CodeGenOptions;
33namespace CodeGen {
34
35/// Attributes that may be specified on loops.
36struct LoopAttributes {
37 explicit LoopAttributes(bool IsParallel = false);
38 void clear();
39
40 /// Generate llvm.loop.parallel metadata for loads and stores.
41 bool IsParallel;
42
43 /// State of loop vectorization or unrolling.
44 enum LVEnableState { Unspecified, Enable, Disable, Full };
45
46 /// Value for llvm.loop.vectorize.enable metadata.
47 LVEnableState VectorizeEnable;
48
49 /// Value for llvm.loop.unroll.* metadata (enable, disable, or full).
50 LVEnableState UnrollEnable;
51
52 /// Value for llvm.loop.unroll_and_jam.* metadata (enable, disable, or full).
53 LVEnableState UnrollAndJamEnable;
54
55 /// Value for llvm.loop.vectorize.predicate metadata
56 LVEnableState VectorizePredicateEnable;
57
58 /// Value for llvm.loop.vectorize.width metadata.
59 unsigned VectorizeWidth;
60
61 // Value for llvm.loop.vectorize.scalable.enable
62 LVEnableState VectorizeScalable;
63
64 /// Value for llvm.loop.interleave.count metadata.
65 unsigned InterleaveCount;
66
67 /// llvm.unroll.
68 unsigned UnrollCount;
69
70 /// llvm.unroll.
71 unsigned UnrollAndJamCount;
72
73 /// Value for llvm.loop.distribute.enable metadata.
74 LVEnableState DistributeEnable;
75
76 /// Value for llvm.loop.pipeline.disable metadata.
77 bool PipelineDisabled;
78
79 /// Value for llvm.loop.pipeline.iicount metadata.
80 unsigned PipelineInitiationInterval;
81
82 /// Value for whether the loop is required to make progress.
83 bool MustProgress;
84};
85
86/// Information used when generating a structured loop.
87class LoopInfo {
88public:
89 /// Construct a new LoopInfo for the loop with entry Header.
90 LoopInfo(llvm::BasicBlock *Header, const LoopAttributes &Attrs,
91 const llvm::DebugLoc &StartLoc, const llvm::DebugLoc &EndLoc,
92 LoopInfo *Parent);
93
94 /// Get the loop id metadata for this loop.
95 llvm::MDNode *getLoopID() const { return TempLoopID.get(); }
96
97 /// Get the header block of this loop.
98 llvm::BasicBlock *getHeader() const { return Header; }
99
100 /// Get the set of attributes active for this loop.
101 const LoopAttributes &getAttributes() const { return Attrs; }
102
103 /// Return this loop's access group or nullptr if it does not have one.
104 llvm::MDNode *getAccessGroup() const { return AccGroup; }
105
106 /// Create the loop's metadata. Must be called after its nested loops have
107 /// been processed.
108 void finish();
109
110private:
111 /// Loop ID metadata.
112 llvm::TempMDTuple TempLoopID;
113 /// Header block of this loop.
114 llvm::BasicBlock *Header;
115 /// The attributes for this loop.
116 LoopAttributes Attrs;
117 /// The access group for memory accesses parallel to this loop.
118 llvm::MDNode *AccGroup = nullptr;
119 /// Start location of this loop.
120 llvm::DebugLoc StartLoc;
121 /// End location of this loop.
122 llvm::DebugLoc EndLoc;
123 /// The next outer loop, or nullptr if this is the outermost loop.
124 LoopInfo *Parent;
125 /// If this loop has unroll-and-jam metadata, this can be set by the inner
126 /// loop's LoopInfo to set the llvm.loop.unroll_and_jam.followup_inner
127 /// metadata.
128 llvm::MDNode *UnrollAndJamInnerFollowup = nullptr;
129
130 /// Create a LoopID without any transformations.
131 llvm::MDNode *
132 createLoopPropertiesMetadata(llvm::ArrayRef<llvm::Metadata *> LoopProperties);
133
134 /// Create a LoopID for transformations.
135 ///
136 /// The methods call each other in case multiple transformations are applied
137 /// to a loop. The transformation first to be applied will use LoopID of the
138 /// next transformation in its followup attribute.
139 ///
140 /// @param Attrs The loop's transformations.
141 /// @param LoopProperties Non-transformation properties such as debug
142 /// location, parallel accesses and disabled
143 /// transformations. These are added to the returned
144 /// LoopID.
145 /// @param HasUserTransforms [out] Set to true if the returned MDNode encodes
146 /// at least one transformation.
147 ///
148 /// @return A LoopID (metadata node) that can be used for the llvm.loop
149 /// annotation or followup-attribute.
150 /// @{
151 llvm::MDNode *
152 createPipeliningMetadata(const LoopAttributes &Attrs,
153 llvm::ArrayRef<llvm::Metadata *> LoopProperties,
154 bool &HasUserTransforms);
155 llvm::MDNode *
156 createPartialUnrollMetadata(const LoopAttributes &Attrs,
157 llvm::ArrayRef<llvm::Metadata *> LoopProperties,
158 bool &HasUserTransforms);
159 llvm::MDNode *
160 createUnrollAndJamMetadata(const LoopAttributes &Attrs,
161 llvm::ArrayRef<llvm::Metadata *> LoopProperties,
162 bool &HasUserTransforms);
163 llvm::MDNode *
164 createLoopVectorizeMetadata(const LoopAttributes &Attrs,
165 llvm::ArrayRef<llvm::Metadata *> LoopProperties,
166 bool &HasUserTransforms);
167 llvm::MDNode *
168 createLoopDistributeMetadata(const LoopAttributes &Attrs,
169 llvm::ArrayRef<llvm::Metadata *> LoopProperties,
170 bool &HasUserTransforms);
171 llvm::MDNode *
172 createFullUnrollMetadata(const LoopAttributes &Attrs,
173 llvm::ArrayRef<llvm::Metadata *> LoopProperties,
174 bool &HasUserTransforms);
175 /// @}
176
177 /// Create a LoopID for this loop, including transformation-unspecific
178 /// metadata such as debug location.
179 ///
180 /// @param Attrs This loop's attributes and transformations.
181 /// @param LoopProperties Additional non-transformation properties to add
182 /// to the LoopID, such as transformation-specific
183 /// metadata that are not covered by @p Attrs.
184 /// @param HasUserTransforms [out] Set to true if the returned MDNode encodes
185 /// at least one transformation.
186 ///
187 /// @return A LoopID (metadata node) that can be used for the llvm.loop
188 /// annotation.
189 llvm::MDNode *createMetadata(const LoopAttributes &Attrs,
190 llvm::ArrayRef<llvm::Metadata *> LoopProperties,
191 bool &HasUserTransforms);
192};
193
194/// A stack of loop information corresponding to loop nesting levels.
195/// This stack can be used to prepare attributes which are applied when a loop
196/// is emitted.
197class LoopInfoStack {
198 LoopInfoStack(const LoopInfoStack &) = delete;
199 void operator=(const LoopInfoStack &) = delete;
200
201public:
202 LoopInfoStack() {}
203
204 /// Begin a new structured loop. The set of staged attributes will be
205 /// applied to the loop and then cleared.
206 void push(llvm::BasicBlock *Header, const llvm::DebugLoc &StartLoc,
207 const llvm::DebugLoc &EndLoc);
208
209 /// Begin a new structured loop. Stage attributes from the Attrs list.
210 /// The staged attributes are applied to the loop and then cleared.
211 void push(llvm::BasicBlock *Header, clang::ASTContext &Ctx,
212 const clang::CodeGenOptions &CGOpts,
213 llvm::ArrayRef<const Attr *> Attrs, const llvm::DebugLoc &StartLoc,
214 const llvm::DebugLoc &EndLoc, bool MustProgress = false);
215
216 /// End the current loop.
217 void pop();
218
219 /// Return the top loop id metadata.
220 llvm::MDNode *getCurLoopID() const { return getInfo().getLoopID(); }
221
222 /// Return true if the top loop is parallel.
223 bool getCurLoopParallel() const {
224 return hasInfo() ? getInfo().getAttributes().IsParallel : false;
225 }
226
227 /// Function called by the CodeGenFunction when an instruction is
228 /// created.
229 void InsertHelper(llvm::Instruction *I) const;
230
231 /// Set the next pushed loop as parallel.
232 void setParallel(bool Enable = true) { StagedAttrs.IsParallel = Enable; }
233
234 /// Set the next pushed loop 'vectorize.enable'
235 void setVectorizeEnable(bool Enable = true) {
236 StagedAttrs.VectorizeEnable =
237 Enable ? LoopAttributes::Enable : LoopAttributes::Disable;
238 }
239
240 /// Set the next pushed loop as a distribution candidate.
241 void setDistributeState(bool Enable = true) {
242 StagedAttrs.DistributeEnable =
243 Enable ? LoopAttributes::Enable : LoopAttributes::Disable;
244 }
245
246 /// Set the next pushed loop unroll state.
247 void setUnrollState(const LoopAttributes::LVEnableState &State) {
248 StagedAttrs.UnrollEnable = State;
249 }
250
251 /// Set the next pushed vectorize predicate state.
252 void setVectorizePredicateState(const LoopAttributes::LVEnableState &State) {
253 StagedAttrs.VectorizePredicateEnable = State;
254 }
255
256 /// Set the next pushed loop unroll_and_jam state.
257 void setUnrollAndJamState(const LoopAttributes::LVEnableState &State) {
258 StagedAttrs.UnrollAndJamEnable = State;
259 }
260
261 /// Set the vectorize width for the next loop pushed.
262 void setVectorizeWidth(unsigned W) { StagedAttrs.VectorizeWidth = W; }
263
264 void setVectorizeScalable(const LoopAttributes::LVEnableState &State) {
265 StagedAttrs.VectorizeScalable = State;
266 }
267
268 /// Set the interleave count for the next loop pushed.
269 void setInterleaveCount(unsigned C) { StagedAttrs.InterleaveCount = C; }
270
271 /// Set the unroll count for the next loop pushed.
272 void setUnrollCount(unsigned C) { StagedAttrs.UnrollCount = C; }
273
274 /// \brief Set the unroll count for the next loop pushed.
275 void setUnrollAndJamCount(unsigned C) { StagedAttrs.UnrollAndJamCount = C; }
276
277 /// Set the pipeline disabled state.
278 void setPipelineDisabled(bool S) { StagedAttrs.PipelineDisabled = S; }
279
280 /// Set the pipeline initiation interval.
281 void setPipelineInitiationInterval(unsigned C) {
282 StagedAttrs.PipelineInitiationInterval = C;
283 }
284
285 /// Set no progress for the next loop pushed.
286 void setMustProgress(bool P) { StagedAttrs.MustProgress = P; }
287
288private:
289 /// Returns true if there is LoopInfo on the stack.
290 bool hasInfo() const { return !Active.empty(); }
291 /// Return the LoopInfo for the current loop. HasInfo should be called
292 /// first to ensure LoopInfo is present.
293 const LoopInfo &getInfo() const { return *Active.back(); }
294 /// The set of attributes that will be applied to the next pushed loop.
295 LoopAttributes StagedAttrs;
296 /// Stack of active loops.
297 llvm::SmallVector<std::unique_ptr<LoopInfo>, 4> Active;
298};
299
300} // end namespace CodeGen
301} // end namespace clang
302
303#endif
304