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 
20 MDString *MDBuilder::createString(StringRef Str) {
21   return MDString::get(Context, Str);
22 }
23 
24 ConstantAsMetadata *MDBuilder::createConstant(Constant *C) {
25   return ConstantAsMetadata::get(C);
26 }
27 
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 
37 MDNode *MDBuilder::createBranchWeights(uint32_t TrueWeight,
38                                        uint32_t FalseWeight) {
39   uint32_t Weights[] = {TrueWeight, FalseWeight};
40   return createBranchWeights(Weights);
41 }
42 
43 MDNode *MDBuilder::createBranchWeights(ArrayRef<uint32_t> Weights) {
44   assert(Weights.size() >= 2 && "Need at least two branch weights!");
45 
46   SmallVector<Metadata *, 4> Vals(Weights.size() + 1);
47   Vals[0] = createString("branch_weights");
48 
49   Type *Int32Ty = Type::getInt32Ty(Context);
50   for (unsigned i = 0, e = Weights.size(); i != e; ++i)
51     Vals[i + 1] = createConstant(ConstantInt::get(Int32Ty, Weights[i]));
52 
53   return MDNode::get(Context, Vals);
54 }
55 
56 MDNode *MDBuilder::createFunctionEntryCount(uint64_t Count) {
57   SmallVector<Metadata *, 2> Vals(2);
58   Vals[0] = createString("function_entry_count");
59 
60   Type *Int64Ty = Type::getInt64Ty(Context);
61   Vals[1] = createConstant(ConstantInt::get(Int64Ty, Count));
62 
63   return MDNode::get(Context, Vals);
64 }
65 
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 
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   Metadata *Range[2] = {createConstant(Lo), createConstant(Hi)};
80   return MDNode::get(Context, Range);
81 }
82 
83 MDNode *MDBuilder::createAnonymousAARoot(StringRef Name, MDNode *Extra) {
84   // To ensure uniqueness the root node is self-referential.
85   auto Dummy = MDNode::getTemporary(Context, None);
86 
87   SmallVector<Metadata *, 3> Args(1, Dummy.get());
88   if (Extra)
89     Args.push_back(Extra);
90   if (!Name.empty())
91     Args.push_back(createString(Name));
92   MDNode *Root = MDNode::get(Context, Args);
93 
94   // At this point we have
95   //   !0 = metadata !{}            <- dummy
96   //   !1 = metadata !{metadata !0} <- root
97   // Replace the dummy operand with the root node itself and delete the dummy.
98   Root->replaceOperandWith(0, Root);
99 
100   // We now have
101   //   !1 = metadata !{metadata !1} <- self-referential root
102   return Root;
103 }
104 
105 MDNode *MDBuilder::createTBAARoot(StringRef Name) {
106   return MDNode::get(Context, createString(Name));
107 }
108 
109 /// \brief Return metadata for a non-root TBAA node with the given name,
110 /// parent in the TBAA tree, and value for 'pointsToConstantMemory'.
111 MDNode *MDBuilder::createTBAANode(StringRef Name, MDNode *Parent,
112                                   bool isConstant) {
113   if (isConstant) {
114     Constant *Flags = ConstantInt::get(Type::getInt64Ty(Context), 1);
115     Metadata *Ops[3] = {createString(Name), Parent, createConstant(Flags)};
116     return MDNode::get(Context, Ops);
117   } else {
118     Metadata *Ops[2] = {createString(Name), Parent};
119     return MDNode::get(Context, Ops);
120   }
121 }
122 
123 MDNode *MDBuilder::createAliasScopeDomain(StringRef Name) {
124   return MDNode::get(Context, createString(Name));
125 }
126 
127 MDNode *MDBuilder::createAliasScope(StringRef Name, MDNode *Domain) {
128   Metadata *Ops[2] = {createString(Name), Domain};
129   return MDNode::get(Context, Ops);
130 }
131 
132 /// \brief Return metadata for a tbaa.struct node with the given
133 /// struct field descriptions.
134 MDNode *MDBuilder::createTBAAStructNode(ArrayRef<TBAAStructField> Fields) {
135   SmallVector<Metadata *, 4> Vals(Fields.size() * 3);
136   Type *Int64 = Type::getInt64Ty(Context);
137   for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
138     Vals[i * 3 + 0] = createConstant(ConstantInt::get(Int64, Fields[i].Offset));
139     Vals[i * 3 + 1] = createConstant(ConstantInt::get(Int64, Fields[i].Size));
140     Vals[i * 3 + 2] = Fields[i].TBAA;
141   }
142   return MDNode::get(Context, Vals);
143 }
144 
145 /// \brief Return metadata for a TBAA struct node in the type DAG
146 /// with the given name, a list of pairs (offset, field type in the type DAG).
147 MDNode *MDBuilder::createTBAAStructTypeNode(
148     StringRef Name, ArrayRef<std::pair<MDNode *, uint64_t>> Fields) {
149   SmallVector<Metadata *, 4> Ops(Fields.size() * 2 + 1);
150   Type *Int64 = Type::getInt64Ty(Context);
151   Ops[0] = createString(Name);
152   for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
153     Ops[i * 2 + 1] = Fields[i].first;
154     Ops[i * 2 + 2] = createConstant(ConstantInt::get(Int64, Fields[i].second));
155   }
156   return MDNode::get(Context, Ops);
157 }
158 
159 /// \brief Return metadata for a TBAA scalar type node with the
160 /// given name, an offset and a parent in the TBAA type DAG.
161 MDNode *MDBuilder::createTBAAScalarTypeNode(StringRef Name, MDNode *Parent,
162                                             uint64_t Offset) {
163   ConstantInt *Off = ConstantInt::get(Type::getInt64Ty(Context), Offset);
164   Metadata *Ops[3] = {createString(Name), Parent, createConstant(Off)};
165   return MDNode::get(Context, Ops);
166 }
167 
168 /// \brief Return metadata for a TBAA tag node with the given
169 /// base type, access type and offset relative to the base type.
170 MDNode *MDBuilder::createTBAAStructTagNode(MDNode *BaseType, MDNode *AccessType,
171                                            uint64_t Offset, bool IsConstant) {
172   Type *Int64 = Type::getInt64Ty(Context);
173   if (IsConstant) {
174     Metadata *Ops[4] = {BaseType, AccessType,
175                         createConstant(ConstantInt::get(Int64, Offset)),
176                         createConstant(ConstantInt::get(Int64, 1))};
177     return MDNode::get(Context, Ops);
178   } else {
179     Metadata *Ops[3] = {BaseType, AccessType,
180                         createConstant(ConstantInt::get(Int64, Offset))};
181     return MDNode::get(Context, Ops);
182   }
183 }
184