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::createRange(const APInt &Lo, const APInt &Hi) {
57   assert(Lo.getBitWidth() == Hi.getBitWidth() && "Mismatched bitwidths!");
58   // If the range is everything then it is useless.
59   if (Hi == Lo)
60     return nullptr;
61 
62   // Return the range [Lo, Hi).
63   Type *Ty = IntegerType::get(Context, Lo.getBitWidth());
64   Metadata *Range[2] = {createConstant(ConstantInt::get(Ty, Lo)),
65                         createConstant(ConstantInt::get(Ty, Hi))};
66   return MDNode::get(Context, Range);
67 }
68 
69 MDNode *MDBuilder::createAnonymousAARoot(StringRef Name, MDNode *Extra) {
70   // To ensure uniqueness the root node is self-referential.
71   MDNode *Dummy = MDNode::getTemporary(Context, None);
72 
73   SmallVector<Metadata *, 3> Args(1, Dummy);
74   if (Extra)
75     Args.push_back(Extra);
76   if (!Name.empty())
77     Args.push_back(createString(Name));
78   MDNode *Root = MDNode::get(Context, Args);
79 
80   // At this point we have
81   //   !0 = metadata !{}            <- dummy
82   //   !1 = metadata !{metadata !0} <- root
83   // Replace the dummy operand with the root node itself and delete the dummy.
84   Root->replaceOperandWith(0, Root);
85   MDNode::deleteTemporary(Dummy);
86   // We now have
87   //   !1 = metadata !{metadata !1} <- self-referential root
88   return Root;
89 }
90 
91 MDNode *MDBuilder::createTBAARoot(StringRef Name) {
92   return MDNode::get(Context, createString(Name));
93 }
94 
95 /// \brief Return metadata for a non-root TBAA node with the given name,
96 /// parent in the TBAA tree, and value for 'pointsToConstantMemory'.
97 MDNode *MDBuilder::createTBAANode(StringRef Name, MDNode *Parent,
98                                   bool isConstant) {
99   if (isConstant) {
100     Constant *Flags = ConstantInt::get(Type::getInt64Ty(Context), 1);
101     Metadata *Ops[3] = {createString(Name), Parent, createConstant(Flags)};
102     return MDNode::get(Context, Ops);
103   } else {
104     Metadata *Ops[2] = {createString(Name), Parent};
105     return MDNode::get(Context, Ops);
106   }
107 }
108 
109 MDNode *MDBuilder::createAliasScopeDomain(StringRef Name) {
110   return MDNode::get(Context, createString(Name));
111 }
112 
113 MDNode *MDBuilder::createAliasScope(StringRef Name, MDNode *Domain) {
114   Metadata *Ops[2] = {createString(Name), Domain};
115   return MDNode::get(Context, Ops);
116 }
117 
118 /// \brief Return metadata for a tbaa.struct node with the given
119 /// struct field descriptions.
120 MDNode *MDBuilder::createTBAAStructNode(ArrayRef<TBAAStructField> Fields) {
121   SmallVector<Metadata *, 4> Vals(Fields.size() * 3);
122   Type *Int64 = Type::getInt64Ty(Context);
123   for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
124     Vals[i * 3 + 0] = createConstant(ConstantInt::get(Int64, Fields[i].Offset));
125     Vals[i * 3 + 1] = createConstant(ConstantInt::get(Int64, Fields[i].Size));
126     Vals[i * 3 + 2] = Fields[i].TBAA;
127   }
128   return MDNode::get(Context, Vals);
129 }
130 
131 /// \brief Return metadata for a TBAA struct node in the type DAG
132 /// with the given name, a list of pairs (offset, field type in the type DAG).
133 MDNode *MDBuilder::createTBAAStructTypeNode(
134     StringRef Name, ArrayRef<std::pair<MDNode *, uint64_t>> Fields) {
135   SmallVector<Metadata *, 4> Ops(Fields.size() * 2 + 1);
136   Type *Int64 = Type::getInt64Ty(Context);
137   Ops[0] = createString(Name);
138   for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
139     Ops[i * 2 + 1] = Fields[i].first;
140     Ops[i * 2 + 2] = createConstant(ConstantInt::get(Int64, Fields[i].second));
141   }
142   return MDNode::get(Context, Ops);
143 }
144 
145 /// \brief Return metadata for a TBAA scalar type node with the
146 /// given name, an offset and a parent in the TBAA type DAG.
147 MDNode *MDBuilder::createTBAAScalarTypeNode(StringRef Name, MDNode *Parent,
148                                             uint64_t Offset) {
149   ConstantInt *Off = ConstantInt::get(Type::getInt64Ty(Context), Offset);
150   Metadata *Ops[3] = {createString(Name), Parent, createConstant(Off)};
151   return MDNode::get(Context, Ops);
152 }
153 
154 /// \brief Return metadata for a TBAA tag node with the given
155 /// base type, access type and offset relative to the base type.
156 MDNode *MDBuilder::createTBAAStructTagNode(MDNode *BaseType, MDNode *AccessType,
157                                            uint64_t Offset) {
158   Type *Int64 = Type::getInt64Ty(Context);
159   Metadata *Ops[3] = {BaseType, AccessType,
160                       createConstant(ConstantInt::get(Int64, Offset))};
161   return MDNode::get(Context, Ops);
162 }
163