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   return createBranchWeights({TrueWeight, FalseWeight});
40 }
41 
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 
55 MDNode *MDBuilder::createUnpredictable() {
56   return MDNode::get(Context, None);
57 }
58 
59 MDNode *MDBuilder::createFunctionEntryCount(
60     uint64_t Count, const DenseSet<GlobalValue::GUID> *Imports) {
61   Type *Int64Ty = Type::getInt64Ty(Context);
62   SmallVector<Metadata *, 8> Ops;
63   Ops.push_back(createString("function_entry_count"));
64   Ops.push_back(createConstant(ConstantInt::get(Int64Ty, Count)));
65   if (Imports)
66     for (auto ID : *Imports)
67       Ops.push_back(createConstant(ConstantInt::get(Int64Ty, ID)));
68   return MDNode::get(Context, Ops);
69 }
70 
71 MDNode *MDBuilder::createFunctionSectionPrefix(StringRef Prefix) {
72   return MDNode::get(Context,
73                      {createString("function_section_prefix"),
74                       createString(Prefix)});
75 }
76 
77 MDNode *MDBuilder::createRange(const APInt &Lo, const APInt &Hi) {
78   assert(Lo.getBitWidth() == Hi.getBitWidth() && "Mismatched bitwidths!");
79 
80   Type *Ty = IntegerType::get(Context, Lo.getBitWidth());
81   return createRange(ConstantInt::get(Ty, Lo), ConstantInt::get(Ty, Hi));
82 }
83 
84 MDNode *MDBuilder::createRange(Constant *Lo, Constant *Hi) {
85   // If the range is everything then it is useless.
86   if (Hi == Lo)
87     return nullptr;
88 
89   // Return the range [Lo, Hi).
90   return MDNode::get(Context, {createConstant(Lo), createConstant(Hi)});
91 }
92 
93 MDNode *MDBuilder::createAnonymousAARoot(StringRef Name, MDNode *Extra) {
94   // To ensure uniqueness the root node is self-referential.
95   auto Dummy = MDNode::getTemporary(Context, None);
96 
97   SmallVector<Metadata *, 3> Args(1, Dummy.get());
98   if (Extra)
99     Args.push_back(Extra);
100   if (!Name.empty())
101     Args.push_back(createString(Name));
102   MDNode *Root = MDNode::get(Context, Args);
103 
104   // At this point we have
105   //   !0 = metadata !{}            <- dummy
106   //   !1 = metadata !{metadata !0} <- root
107   // Replace the dummy operand with the root node itself and delete the dummy.
108   Root->replaceOperandWith(0, Root);
109 
110   // We now have
111   //   !1 = metadata !{metadata !1} <- self-referential root
112   return Root;
113 }
114 
115 MDNode *MDBuilder::createTBAARoot(StringRef Name) {
116   return MDNode::get(Context, createString(Name));
117 }
118 
119 /// \brief Return metadata for a non-root TBAA node with the given name,
120 /// parent in the TBAA tree, and value for 'pointsToConstantMemory'.
121 MDNode *MDBuilder::createTBAANode(StringRef Name, MDNode *Parent,
122                                   bool isConstant) {
123   if (isConstant) {
124     Constant *Flags = ConstantInt::get(Type::getInt64Ty(Context), 1);
125     return MDNode::get(Context,
126                        {createString(Name), Parent, createConstant(Flags)});
127   }
128   return MDNode::get(Context, {createString(Name), Parent});
129 }
130 
131 MDNode *MDBuilder::createAliasScopeDomain(StringRef Name) {
132   return MDNode::get(Context, createString(Name));
133 }
134 
135 MDNode *MDBuilder::createAliasScope(StringRef Name, MDNode *Domain) {
136   return MDNode::get(Context, {createString(Name), Domain});
137 }
138 
139 /// \brief Return metadata for a tbaa.struct node with the given
140 /// struct field descriptions.
141 MDNode *MDBuilder::createTBAAStructNode(ArrayRef<TBAAStructField> Fields) {
142   SmallVector<Metadata *, 4> Vals(Fields.size() * 3);
143   Type *Int64 = Type::getInt64Ty(Context);
144   for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
145     Vals[i * 3 + 0] = createConstant(ConstantInt::get(Int64, Fields[i].Offset));
146     Vals[i * 3 + 1] = createConstant(ConstantInt::get(Int64, Fields[i].Size));
147     Vals[i * 3 + 2] = Fields[i].TBAA;
148   }
149   return MDNode::get(Context, Vals);
150 }
151 
152 /// \brief Return metadata for a TBAA struct node in the type DAG
153 /// with the given name, a list of pairs (offset, field type in the type DAG).
154 MDNode *MDBuilder::createTBAAStructTypeNode(
155     StringRef Name, ArrayRef<std::pair<MDNode *, uint64_t>> Fields) {
156   SmallVector<Metadata *, 4> Ops(Fields.size() * 2 + 1);
157   Type *Int64 = Type::getInt64Ty(Context);
158   Ops[0] = createString(Name);
159   for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
160     Ops[i * 2 + 1] = Fields[i].first;
161     Ops[i * 2 + 2] = createConstant(ConstantInt::get(Int64, Fields[i].second));
162   }
163   return MDNode::get(Context, Ops);
164 }
165 
166 /// \brief Return metadata for a TBAA scalar type node with the
167 /// given name, an offset and a parent in the TBAA type DAG.
168 MDNode *MDBuilder::createTBAAScalarTypeNode(StringRef Name, MDNode *Parent,
169                                             uint64_t Offset) {
170   ConstantInt *Off = ConstantInt::get(Type::getInt64Ty(Context), Offset);
171   return MDNode::get(Context,
172                      {createString(Name), Parent, createConstant(Off)});
173 }
174 
175 /// \brief Return metadata for a TBAA tag node with the given
176 /// base type, access type and offset relative to the base type.
177 MDNode *MDBuilder::createTBAAStructTagNode(MDNode *BaseType, MDNode *AccessType,
178                                            uint64_t Offset, bool IsConstant) {
179   IntegerType *Int64 = Type::getInt64Ty(Context);
180   ConstantInt *Off = ConstantInt::get(Int64, Offset);
181   if (IsConstant) {
182     return MDNode::get(Context, {BaseType, AccessType, createConstant(Off),
183                                  createConstant(ConstantInt::get(Int64, 1))});
184   }
185   return MDNode::get(Context, {BaseType, AccessType, createConstant(Off)});
186 }
187