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 namespace CodeGen { 33 34 /// Attributes that may be specified on loops. 35 struct LoopAttributes { 36 explicit LoopAttributes(bool IsParallel = false); 37 void clear(); 38 39 /// Generate llvm.loop.parallel metadata for loads and stores. 40 bool IsParallel; 41 42 /// State of loop vectorization or unrolling. 43 enum LVEnableState { Unspecified, Enable, Disable, Full }; 44 45 /// Value for llvm.loop.vectorize.enable metadata. 46 LVEnableState VectorizeEnable; 47 48 /// Value for llvm.loop.unroll.* metadata (enable, disable, or full). 49 LVEnableState UnrollEnable; 50 51 /// Value for llvm.loop.unroll_and_jam.* metadata (enable, disable, or full). 52 LVEnableState UnrollAndJamEnable; 53 54 /// Value for llvm.loop.vectorize.width metadata. 55 unsigned VectorizeWidth; 56 57 /// Value for llvm.loop.interleave.count metadata. 58 unsigned InterleaveCount; 59 60 /// llvm.unroll. 61 unsigned UnrollCount; 62 63 /// llvm.unroll. 64 unsigned UnrollAndJamCount; 65 66 /// Value for llvm.loop.distribute.enable metadata. 67 LVEnableState DistributeEnable; 68 69 /// Value for llvm.loop.pipeline.disable metadata. 70 bool PipelineDisabled; 71 72 /// Value for llvm.loop.pipeline.iicount metadata. 73 unsigned PipelineInitiationInterval; 74 }; 75 76 /// Information used when generating a structured loop. 77 class LoopInfo { 78 public: 79 /// Construct a new LoopInfo for the loop with entry Header. 80 LoopInfo(llvm::BasicBlock *Header, const LoopAttributes &Attrs, 81 const llvm::DebugLoc &StartLoc, const llvm::DebugLoc &EndLoc); 82 83 /// Get the loop id metadata for this loop. 84 llvm::MDNode *getLoopID() const { return LoopID; } 85 86 /// Get the header block of this loop. 87 llvm::BasicBlock *getHeader() const { return Header; } 88 89 /// Get the set of attributes active for this loop. 90 const LoopAttributes &getAttributes() const { return Attrs; } 91 92 /// Return this loop's access group or nullptr if it does not have one. 93 llvm::MDNode *getAccessGroup() const { return AccGroup; } 94 95 private: 96 /// Loop ID metadata. 97 llvm::MDNode *LoopID; 98 /// Header block of this loop. 99 llvm::BasicBlock *Header; 100 /// The attributes for this loop. 101 LoopAttributes Attrs; 102 /// The access group for memory accesses parallel to this loop. 103 llvm::MDNode *AccGroup = nullptr; 104 }; 105 106 /// A stack of loop information corresponding to loop nesting levels. 107 /// This stack can be used to prepare attributes which are applied when a loop 108 /// is emitted. 109 class LoopInfoStack { 110 LoopInfoStack(const LoopInfoStack &) = delete; 111 void operator=(const LoopInfoStack &) = delete; 112 113 public: 114 LoopInfoStack() {} 115 116 /// Begin a new structured loop. The set of staged attributes will be 117 /// applied to the loop and then cleared. 118 void push(llvm::BasicBlock *Header, const llvm::DebugLoc &StartLoc, 119 const llvm::DebugLoc &EndLoc); 120 121 /// Begin a new structured loop. Stage attributes from the Attrs list. 122 /// The staged attributes are applied to the loop and then cleared. 123 void push(llvm::BasicBlock *Header, clang::ASTContext &Ctx, 124 llvm::ArrayRef<const Attr *> Attrs, const llvm::DebugLoc &StartLoc, 125 const llvm::DebugLoc &EndLoc); 126 127 /// End the current loop. 128 void pop(); 129 130 /// Return the top loop id metadata. 131 llvm::MDNode *getCurLoopID() const { return getInfo().getLoopID(); } 132 133 /// Return true if the top loop is parallel. 134 bool getCurLoopParallel() const { 135 return hasInfo() ? getInfo().getAttributes().IsParallel : false; 136 } 137 138 /// Function called by the CodeGenFunction when an instruction is 139 /// created. 140 void InsertHelper(llvm::Instruction *I) const; 141 142 /// Set the next pushed loop as parallel. 143 void setParallel(bool Enable = true) { StagedAttrs.IsParallel = Enable; } 144 145 /// Set the next pushed loop 'vectorize.enable' 146 void setVectorizeEnable(bool Enable = true) { 147 StagedAttrs.VectorizeEnable = 148 Enable ? LoopAttributes::Enable : LoopAttributes::Disable; 149 } 150 151 /// Set the next pushed loop as a distribution candidate. 152 void setDistributeState(bool Enable = true) { 153 StagedAttrs.DistributeEnable = 154 Enable ? LoopAttributes::Enable : LoopAttributes::Disable; 155 } 156 157 /// Set the next pushed loop unroll state. 158 void setUnrollState(const LoopAttributes::LVEnableState &State) { 159 StagedAttrs.UnrollEnable = State; 160 } 161 162 /// Set the next pushed loop unroll_and_jam state. 163 void setUnrollAndJamState(const LoopAttributes::LVEnableState &State) { 164 StagedAttrs.UnrollAndJamEnable = State; 165 } 166 167 /// Set the vectorize width for the next loop pushed. 168 void setVectorizeWidth(unsigned W) { StagedAttrs.VectorizeWidth = W; } 169 170 /// Set the interleave count for the next loop pushed. 171 void setInterleaveCount(unsigned C) { StagedAttrs.InterleaveCount = C; } 172 173 /// Set the unroll count for the next loop pushed. 174 void setUnrollCount(unsigned C) { StagedAttrs.UnrollCount = C; } 175 176 /// \brief Set the unroll count for the next loop pushed. 177 void setUnrollAndJamCount(unsigned C) { StagedAttrs.UnrollAndJamCount = C; } 178 179 /// Set the pipeline disabled state. 180 void setPipelineDisabled(bool S) { StagedAttrs.PipelineDisabled = S; } 181 182 /// Set the pipeline initiation interval. 183 void setPipelineInitiationInterval(unsigned C) { 184 StagedAttrs.PipelineInitiationInterval = C; 185 } 186 187 private: 188 /// Returns true if there is LoopInfo on the stack. 189 bool hasInfo() const { return !Active.empty(); } 190 /// Return the LoopInfo for the current loop. HasInfo should be called 191 /// first to ensure LoopInfo is present. 192 const LoopInfo &getInfo() const { return Active.back(); } 193 /// The set of attributes that will be applied to the next pushed loop. 194 LoopAttributes StagedAttrs; 195 /// Stack of active loops. 196 llvm::SmallVector<LoopInfo, 4> Active; 197 }; 198 199 } // end namespace CodeGen 200 } // end namespace clang 201 202 #endif 203