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 23 namespace llvm { 24 class BasicBlock; 25 class Instruction; 26 class MDNode; 27 } // end namespace llvm 28 29 namespace clang { 30 class Attr; 31 class ASTContext; 32 class CodeGenOptions; 33 namespace CodeGen { 34 35 /// Attributes that may be specified on loops. 36 struct 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. 87 class LoopInfo { 88 public: 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(); 109 110 private: 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. 197 class LoopInfoStack { 198 LoopInfoStack(const LoopInfoStack &) = delete; 199 void operator=(const LoopInfoStack &) = delete; 200 201 public: 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; } 287 288 private: 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