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