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1 //===---- llvm/MDBuilder.cpp - Builder for LLVM metadata ------------------===//
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 #include "llvm/IR/MDBuilder.h"
16 #include "llvm/IR/Constants.h"
17 #include "llvm/IR/Metadata.h"
18 using namespace llvm;
19 
createString(StringRef Str)20 MDString *MDBuilder::createString(StringRef Str) {
21   return MDString::get(Context, Str);
22 }
23 
createConstant(Constant * C)24 ConstantAsMetadata *MDBuilder::createConstant(Constant *C) {
25   return ConstantAsMetadata::get(C);
26 }
27 
createFPMath(float Accuracy)28 MDNode *MDBuilder::createFPMath(float Accuracy) {
29   if (Accuracy == 0.0)
30     return nullptr;
31   assert(Accuracy > 0.0 && "Invalid fpmath accuracy!");
32   auto *Op =
33       createConstant(ConstantFP::get(Type::getFloatTy(Context), Accuracy));
34   return MDNode::get(Context, Op);
35 }
36 
createBranchWeights(uint32_t TrueWeight,uint32_t FalseWeight)37 MDNode *MDBuilder::createBranchWeights(uint32_t TrueWeight,
38                                        uint32_t FalseWeight) {
39   return createBranchWeights({TrueWeight, FalseWeight});
40 }
41 
createBranchWeights(ArrayRef<uint32_t> Weights)42 MDNode *MDBuilder::createBranchWeights(ArrayRef<uint32_t> Weights) {
43   assert(Weights.size() >= 1 && "Need at least one branch weights!");
44 
45   SmallVector<Metadata *, 4> Vals(Weights.size() + 1);
46   Vals[0] = createString("branch_weights");
47 
48   Type *Int32Ty = Type::getInt32Ty(Context);
49   for (unsigned i = 0, e = Weights.size(); i != e; ++i)
50     Vals[i + 1] = createConstant(ConstantInt::get(Int32Ty, Weights[i]));
51 
52   return MDNode::get(Context, Vals);
53 }
54 
createUnpredictable()55 MDNode *MDBuilder::createUnpredictable() {
56   return MDNode::get(Context, None);
57 }
58 
createFunctionEntryCount(uint64_t Count)59 MDNode *MDBuilder::createFunctionEntryCount(uint64_t Count) {
60   Type *Int64Ty = Type::getInt64Ty(Context);
61   return MDNode::get(Context,
62                      {createString("function_entry_count"),
63                       createConstant(ConstantInt::get(Int64Ty, Count))});
64 }
65 
createRange(const APInt & Lo,const APInt & Hi)66 MDNode *MDBuilder::createRange(const APInt &Lo, const APInt &Hi) {
67   assert(Lo.getBitWidth() == Hi.getBitWidth() && "Mismatched bitwidths!");
68 
69   Type *Ty = IntegerType::get(Context, Lo.getBitWidth());
70   return createRange(ConstantInt::get(Ty, Lo), ConstantInt::get(Ty, Hi));
71 }
72 
createRange(Constant * Lo,Constant * Hi)73 MDNode *MDBuilder::createRange(Constant *Lo, Constant *Hi) {
74   // If the range is everything then it is useless.
75   if (Hi == Lo)
76     return nullptr;
77 
78   // Return the range [Lo, Hi).
79   return MDNode::get(Context, {createConstant(Lo), createConstant(Hi)});
80 }
81 
createAnonymousAARoot(StringRef Name,MDNode * Extra)82 MDNode *MDBuilder::createAnonymousAARoot(StringRef Name, MDNode *Extra) {
83   // To ensure uniqueness the root node is self-referential.
84   auto Dummy = MDNode::getTemporary(Context, None);
85 
86   SmallVector<Metadata *, 3> Args(1, Dummy.get());
87   if (Extra)
88     Args.push_back(Extra);
89   if (!Name.empty())
90     Args.push_back(createString(Name));
91   MDNode *Root = MDNode::get(Context, Args);
92 
93   // At this point we have
94   //   !0 = metadata !{}            <- dummy
95   //   !1 = metadata !{metadata !0} <- root
96   // Replace the dummy operand with the root node itself and delete the dummy.
97   Root->replaceOperandWith(0, Root);
98 
99   // We now have
100   //   !1 = metadata !{metadata !1} <- self-referential root
101   return Root;
102 }
103 
createTBAARoot(StringRef Name)104 MDNode *MDBuilder::createTBAARoot(StringRef Name) {
105   return MDNode::get(Context, createString(Name));
106 }
107 
108 /// \brief Return metadata for a non-root TBAA node with the given name,
109 /// parent in the TBAA tree, and value for 'pointsToConstantMemory'.
createTBAANode(StringRef Name,MDNode * Parent,bool isConstant)110 MDNode *MDBuilder::createTBAANode(StringRef Name, MDNode *Parent,
111                                   bool isConstant) {
112   if (isConstant) {
113     Constant *Flags = ConstantInt::get(Type::getInt64Ty(Context), 1);
114     return MDNode::get(Context,
115                        {createString(Name), Parent, createConstant(Flags)});
116   }
117   return MDNode::get(Context, {createString(Name), Parent});
118 }
119 
createAliasScopeDomain(StringRef Name)120 MDNode *MDBuilder::createAliasScopeDomain(StringRef Name) {
121   return MDNode::get(Context, createString(Name));
122 }
123 
createAliasScope(StringRef Name,MDNode * Domain)124 MDNode *MDBuilder::createAliasScope(StringRef Name, MDNode *Domain) {
125   return MDNode::get(Context, {createString(Name), Domain});
126 }
127 
128 /// \brief Return metadata for a tbaa.struct node with the given
129 /// struct field descriptions.
createTBAAStructNode(ArrayRef<TBAAStructField> Fields)130 MDNode *MDBuilder::createTBAAStructNode(ArrayRef<TBAAStructField> Fields) {
131   SmallVector<Metadata *, 4> Vals(Fields.size() * 3);
132   Type *Int64 = Type::getInt64Ty(Context);
133   for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
134     Vals[i * 3 + 0] = createConstant(ConstantInt::get(Int64, Fields[i].Offset));
135     Vals[i * 3 + 1] = createConstant(ConstantInt::get(Int64, Fields[i].Size));
136     Vals[i * 3 + 2] = Fields[i].TBAA;
137   }
138   return MDNode::get(Context, Vals);
139 }
140 
141 /// \brief Return metadata for a TBAA struct node in the type DAG
142 /// with the given name, a list of pairs (offset, field type in the type DAG).
createTBAAStructTypeNode(StringRef Name,ArrayRef<std::pair<MDNode *,uint64_t>> Fields)143 MDNode *MDBuilder::createTBAAStructTypeNode(
144     StringRef Name, ArrayRef<std::pair<MDNode *, uint64_t>> Fields) {
145   SmallVector<Metadata *, 4> Ops(Fields.size() * 2 + 1);
146   Type *Int64 = Type::getInt64Ty(Context);
147   Ops[0] = createString(Name);
148   for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
149     Ops[i * 2 + 1] = Fields[i].first;
150     Ops[i * 2 + 2] = createConstant(ConstantInt::get(Int64, Fields[i].second));
151   }
152   return MDNode::get(Context, Ops);
153 }
154 
155 /// \brief Return metadata for a TBAA scalar type node with the
156 /// given name, an offset and a parent in the TBAA type DAG.
createTBAAScalarTypeNode(StringRef Name,MDNode * Parent,uint64_t Offset)157 MDNode *MDBuilder::createTBAAScalarTypeNode(StringRef Name, MDNode *Parent,
158                                             uint64_t Offset) {
159   ConstantInt *Off = ConstantInt::get(Type::getInt64Ty(Context), Offset);
160   return MDNode::get(Context,
161                      {createString(Name), Parent, createConstant(Off)});
162 }
163 
164 /// \brief Return metadata for a TBAA tag node with the given
165 /// base type, access type and offset relative to the base type.
createTBAAStructTagNode(MDNode * BaseType,MDNode * AccessType,uint64_t Offset,bool IsConstant)166 MDNode *MDBuilder::createTBAAStructTagNode(MDNode *BaseType, MDNode *AccessType,
167                                            uint64_t Offset, bool IsConstant) {
168   IntegerType *Int64 = Type::getInt64Ty(Context);
169   ConstantInt *Off = ConstantInt::get(Int64, Offset);
170   if (IsConstant) {
171     return MDNode::get(Context, {BaseType, AccessType, createConstant(Off),
172                                  createConstant(ConstantInt::get(Int64, 1))});
173   }
174   return MDNode::get(Context, {BaseType, AccessType, createConstant(Off)});
175 }
176