MDBuilder.cpp revision dce4a407a24b04eebc6a376f8e62b41aaa7b071f 
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"
18using namespace llvm;
19
20MDString *MDBuilder::createString(StringRef Str) {
21  return MDString::get(Context, Str);
22}
23
24MDNode *MDBuilder::createFPMath(float Accuracy) {
25  if (Accuracy == 0.0)
26    return nullptr;
27  assert(Accuracy > 0.0 && "Invalid fpmath accuracy!");
28  Value *Op = ConstantFP::get(Type::getFloatTy(Context), Accuracy);
29  return MDNode::get(Context, Op);
30}
31
32MDNode *MDBuilder::createBranchWeights(uint32_t TrueWeight,
33                                       uint32_t FalseWeight) {
34  uint32_t Weights[] = {TrueWeight, FalseWeight};
35  return createBranchWeights(Weights);
36}
37
38MDNode *MDBuilder::createBranchWeights(ArrayRef<uint32_t> Weights) {
39  assert(Weights.size() >= 2 && "Need at least two branch weights!");
40
41  SmallVector<Value *, 4> Vals(Weights.size() + 1);
42  Vals[0] = createString("branch_weights");
43
44  Type *Int32Ty = Type::getInt32Ty(Context);
45  for (unsigned i = 0, e = Weights.size(); i != e; ++i)
46    Vals[i + 1] = ConstantInt::get(Int32Ty, Weights[i]);
47
48  return MDNode::get(Context, Vals);
49}
50
51MDNode *MDBuilder::createRange(const APInt &Lo, const APInt &Hi) {
52  assert(Lo.getBitWidth() == Hi.getBitWidth() && "Mismatched bitwidths!");
53  // If the range is everything then it is useless.
54  if (Hi == Lo)
55    return nullptr;
56
57  // Return the range [Lo, Hi).
58  Type *Ty = IntegerType::get(Context, Lo.getBitWidth());
59  Value *Range[2] = {ConstantInt::get(Ty, Lo), ConstantInt::get(Ty, Hi)};
60  return MDNode::get(Context, Range);
61}
62
63MDNode *MDBuilder::createAnonymousTBAARoot() {
64  // To ensure uniqueness the root node is self-referential.
65  MDNode *Dummy = MDNode::getTemporary(Context, ArrayRef<Value *>());
66  MDNode *Root = MDNode::get(Context, Dummy);
67  // At this point we have
68  //   !0 = metadata !{}            <- dummy
69  //   !1 = metadata !{metadata !0} <- root
70  // Replace the dummy operand with the root node itself and delete the dummy.
71  Root->replaceOperandWith(0, Root);
72  MDNode::deleteTemporary(Dummy);
73  // We now have
74  //   !1 = metadata !{metadata !1} <- self-referential root
75  return Root;
76}
77
78MDNode *MDBuilder::createTBAARoot(StringRef Name) {
79  return MDNode::get(Context, createString(Name));
80}
81
82/// \brief Return metadata for a non-root TBAA node with the given name,
83/// parent in the TBAA tree, and value for 'pointsToConstantMemory'.
84MDNode *MDBuilder::createTBAANode(StringRef Name, MDNode *Parent,
85                                  bool isConstant) {
86  if (isConstant) {
87    Constant *Flags = ConstantInt::get(Type::getInt64Ty(Context), 1);
88    Value *Ops[3] = {createString(Name), Parent, Flags};
89    return MDNode::get(Context, Ops);
90  } else {
91    Value *Ops[2] = {createString(Name), Parent};
92    return MDNode::get(Context, Ops);
93  }
94}
95
96/// \brief Return metadata for a tbaa.struct node with the given
97/// struct field descriptions.
98MDNode *MDBuilder::createTBAAStructNode(ArrayRef<TBAAStructField> Fields) {
99  SmallVector<Value *, 4> Vals(Fields.size() * 3);
100  Type *Int64 = Type::getInt64Ty(Context);
101  for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
102    Vals[i * 3 + 0] = ConstantInt::get(Int64, Fields[i].Offset);
103    Vals[i * 3 + 1] = ConstantInt::get(Int64, Fields[i].Size);
104    Vals[i * 3 + 2] = Fields[i].TBAA;
105  }
106  return MDNode::get(Context, Vals);
107}
108
109/// \brief Return metadata for a TBAA struct node in the type DAG
110/// with the given name, a list of pairs (offset, field type in the type DAG).
111MDNode *MDBuilder::createTBAAStructTypeNode(
112    StringRef Name, ArrayRef<std::pair<MDNode *, uint64_t>> Fields) {
113  SmallVector<Value *, 4> Ops(Fields.size() * 2 + 1);
114  Type *Int64 = Type::getInt64Ty(Context);
115  Ops[0] = createString(Name);
116  for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
117    Ops[i * 2 + 1] = Fields[i].first;
118    Ops[i * 2 + 2] = ConstantInt::get(Int64, Fields[i].second);
119  }
120  return MDNode::get(Context, Ops);
121}
122
123/// \brief Return metadata for a TBAA scalar type node with the
124/// given name, an offset and a parent in the TBAA type DAG.
125MDNode *MDBuilder::createTBAAScalarTypeNode(StringRef Name, MDNode *Parent,
126                                            uint64_t Offset) {
127  ConstantInt *Off = ConstantInt::get(Type::getInt64Ty(Context), Offset);
128  Value *Ops[3] = {createString(Name), Parent, Off};
129  return MDNode::get(Context, Ops);
130}
131
132/// \brief Return metadata for a TBAA tag node with the given
133/// base type, access type and offset relative to the base type.
134MDNode *MDBuilder::createTBAAStructTagNode(MDNode *BaseType, MDNode *AccessType,
135                                           uint64_t Offset) {
136  Type *Int64 = Type::getInt64Ty(Context);
137  Value *Ops[3] = {BaseType, AccessType, ConstantInt::get(Int64, Offset)};
138  return MDNode::get(Context, Ops);
139}
140