1 //===---- llvm/MDBuilder.h - Builder for LLVM metadata ----------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file defines the MDBuilder class, which is used as a convenient way to 11 // create LLVM metadata with a consistent and simplified interface. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_IR_MDBUILDER_H 16 #define LLVM_IR_MDBUILDER_H 17 18 #include "llvm/IR/Constants.h" 19 #include "llvm/IR/DerivedTypes.h" 20 #include "llvm/IR/Metadata.h" 21 22 namespace llvm { 23 24 class APInt; 25 class LLVMContext; 26 27 class MDBuilder { 28 LLVMContext &Context; 29 30 public: 31 MDBuilder(LLVMContext &context) : Context(context) {} 32 33 /// \brief Return the given string as metadata. 34 MDString *createString(StringRef Str) { 35 return MDString::get(Context, Str); 36 } 37 38 //===------------------------------------------------------------------===// 39 // FPMath metadata. 40 //===------------------------------------------------------------------===// 41 42 /// \brief Return metadata with the given settings. The special value 0.0 43 /// for the Accuracy parameter indicates the default (maximal precision) 44 /// setting. 45 MDNode *createFPMath(float Accuracy) { 46 if (Accuracy == 0.0) 47 return 0; 48 assert(Accuracy > 0.0 && "Invalid fpmath accuracy!"); 49 Value *Op = ConstantFP::get(Type::getFloatTy(Context), Accuracy); 50 return MDNode::get(Context, Op); 51 } 52 53 //===------------------------------------------------------------------===// 54 // Prof metadata. 55 //===------------------------------------------------------------------===// 56 57 /// \brief Return metadata containing two branch weights. 58 MDNode *createBranchWeights(uint32_t TrueWeight, uint32_t FalseWeight) { 59 uint32_t Weights[] = { TrueWeight, FalseWeight }; 60 return createBranchWeights(Weights); 61 } 62 63 /// \brief Return metadata containing a number of branch weights. 64 MDNode *createBranchWeights(ArrayRef<uint32_t> Weights) { 65 assert(Weights.size() >= 2 && "Need at least two branch weights!"); 66 67 SmallVector<Value *, 4> Vals(Weights.size()+1); 68 Vals[0] = createString("branch_weights"); 69 70 Type *Int32Ty = Type::getInt32Ty(Context); 71 for (unsigned i = 0, e = Weights.size(); i != e; ++i) 72 Vals[i+1] = ConstantInt::get(Int32Ty, Weights[i]); 73 74 return MDNode::get(Context, Vals); 75 } 76 77 //===------------------------------------------------------------------===// 78 // Range metadata. 79 //===------------------------------------------------------------------===// 80 81 /// \brief Return metadata describing the range [Lo, Hi). 82 MDNode *createRange(const APInt &Lo, const APInt &Hi) { 83 assert(Lo.getBitWidth() == Hi.getBitWidth() && "Mismatched bitwidths!"); 84 // If the range is everything then it is useless. 85 if (Hi == Lo) 86 return 0; 87 88 // Return the range [Lo, Hi). 89 Type *Ty = IntegerType::get(Context, Lo.getBitWidth()); 90 Value *Range[2] = { ConstantInt::get(Ty, Lo), ConstantInt::get(Ty, Hi) }; 91 return MDNode::get(Context, Range); 92 } 93 94 95 //===------------------------------------------------------------------===// 96 // TBAA metadata. 97 //===------------------------------------------------------------------===// 98 99 /// \brief Return metadata appropriate for a TBAA root node. Each returned 100 /// node is distinct from all other metadata and will never be identified 101 /// (uniqued) with anything else. 102 MDNode *createAnonymousTBAARoot() { 103 // To ensure uniqueness the root node is self-referential. 104 MDNode *Dummy = MDNode::getTemporary(Context, ArrayRef<Value*>()); 105 MDNode *Root = MDNode::get(Context, Dummy); 106 // At this point we have 107 // !0 = metadata !{} <- dummy 108 // !1 = metadata !{metadata !0} <- root 109 // Replace the dummy operand with the root node itself and delete the dummy. 110 Root->replaceOperandWith(0, Root); 111 MDNode::deleteTemporary(Dummy); 112 // We now have 113 // !1 = metadata !{metadata !1} <- self-referential root 114 return Root; 115 } 116 117 /// \brief Return metadata appropriate for a TBAA root node with the given 118 /// name. This may be identified (uniqued) with other roots with the same 119 /// name. 120 MDNode *createTBAARoot(StringRef Name) { 121 return MDNode::get(Context, createString(Name)); 122 } 123 124 /// \brief Return metadata for a non-root TBAA node with the given name, 125 /// parent in the TBAA tree, and value for 'pointsToConstantMemory'. 126 MDNode *createTBAANode(StringRef Name, MDNode *Parent, 127 bool isConstant = false) { 128 if (isConstant) { 129 Constant *Flags = ConstantInt::get(Type::getInt64Ty(Context), 1); 130 Value *Ops[3] = { createString(Name), Parent, Flags }; 131 return MDNode::get(Context, Ops); 132 } else { 133 Value *Ops[2] = { createString(Name), Parent }; 134 return MDNode::get(Context, Ops); 135 } 136 } 137 138 struct TBAAStructField { 139 uint64_t Offset; 140 uint64_t Size; 141 MDNode *TBAA; 142 TBAAStructField(uint64_t Offset, uint64_t Size, MDNode *TBAA) : 143 Offset(Offset), Size(Size), TBAA(TBAA) {} 144 }; 145 146 /// \brief Return metadata for a tbaa.struct node with the given 147 /// struct field descriptions. 148 MDNode *createTBAAStructNode(ArrayRef<TBAAStructField> Fields) { 149 SmallVector<Value *, 4> Vals(Fields.size() * 3); 150 Type *Int64 = IntegerType::get(Context, 64); 151 for (unsigned i = 0, e = Fields.size(); i != e; ++i) { 152 Vals[i * 3 + 0] = ConstantInt::get(Int64, Fields[i].Offset); 153 Vals[i * 3 + 1] = ConstantInt::get(Int64, Fields[i].Size); 154 Vals[i * 3 + 2] = Fields[i].TBAA; 155 } 156 return MDNode::get(Context, Vals); 157 } 158 159 }; 160 161 } // end namespace llvm 162 163 #endif 164
