1 //===---- llvm/MDBuilder.h - Builder for LLVM metadata ----------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines the MDBuilder class, which is used as a convenient way to
10 // create LLVM metadata with a consistent and simplified interface.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_IR_MDBUILDER_H
15 #define LLVM_IR_MDBUILDER_H
16 
17 #include "llvm/ADT/DenseSet.h"
18 #include "llvm/ADT/StringRef.h"
19 #include "llvm/IR/Constants.h"
20 #include "llvm/IR/GlobalValue.h"
21 #include "llvm/Support/DataTypes.h"
22 #include <utility>
23 
24 namespace llvm {
25 
26 class APInt;
27 template <typename T> class ArrayRef;
28 class LLVMContext;
29 class Constant;
30 class ConstantAsMetadata;
31 class MDNode;
32 class MDString;
33 class Metadata;
34 
35 class MDBuilder {
36   LLVMContext &Context;
37 
38 public:
39   MDBuilder(LLVMContext &context) : Context(context) {}
40 
41   /// Return the given string as metadata.
42   MDString *createString(StringRef Str);
43 
44   /// Return the given constant as metadata.
45   ConstantAsMetadata *createConstant(Constant *C);
46 
47   //===------------------------------------------------------------------===//
48   // FPMath metadata.
49   //===------------------------------------------------------------------===//
50 
51   /// Return metadata with the given settings.  The special value 0.0
52   /// for the Accuracy parameter indicates the default (maximal precision)
53   /// setting.
54   MDNode *createFPMath(float Accuracy);
55 
56   //===------------------------------------------------------------------===//
57   // Prof metadata.
58   //===------------------------------------------------------------------===//
59 
60   /// Return metadata containing two branch weights.
61   MDNode *createBranchWeights(uint32_t TrueWeight, uint32_t FalseWeight);
62 
63   /// Return metadata containing a number of branch weights.
64   MDNode *createBranchWeights(ArrayRef<uint32_t> Weights);
65 
66   /// Return metadata specifying that a branch or switch is unpredictable.
67   MDNode *createUnpredictable();
68 
69   /// Return metadata containing the entry \p Count for a function, a boolean
70   /// \Synthetic indicating whether the counts were synthetized, and the
71   /// GUIDs stored in \p Imports that need to be imported for sample PGO, to
72   /// enable the same inlines as the profiled optimized binary
73   MDNode *createFunctionEntryCount(uint64_t Count, bool Synthetic,
74                                    const DenseSet<GlobalValue::GUID> *Imports);
75 
76   /// Return metadata containing the section prefix for a function.
77   MDNode *createFunctionSectionPrefix(StringRef Prefix);
78 
79   /// Return metadata containing the pseudo probe descriptor for a function.
80   MDNode *createPseudoProbeDesc(uint64_t GUID, uint64_t Hash, Function *F);
81 
82   //===------------------------------------------------------------------===//
83   // Range metadata.
84   //===------------------------------------------------------------------===//
85 
86   /// Return metadata describing the range [Lo, Hi).
87   MDNode *createRange(const APInt &Lo, const APInt &Hi);
88 
89   /// Return metadata describing the range [Lo, Hi).
90   MDNode *createRange(Constant *Lo, Constant *Hi);
91 
92   //===------------------------------------------------------------------===//
93   // Callees metadata.
94   //===------------------------------------------------------------------===//
95 
96   /// Return metadata indicating the possible callees of indirect
97   /// calls.
98   MDNode *createCallees(ArrayRef<Function *> Callees);
99 
100   //===------------------------------------------------------------------===//
101   // Callback metadata.
102   //===------------------------------------------------------------------===//
103 
104   /// Return metadata describing a callback (see llvm::AbstractCallSite).
105   MDNode *createCallbackEncoding(unsigned CalleeArgNo, ArrayRef<int> Arguments,
106                                  bool VarArgsArePassed);
107 
108   /// Merge the new callback encoding \p NewCB into \p ExistingCallbacks.
109   MDNode *mergeCallbackEncodings(MDNode *ExistingCallbacks, MDNode *NewCB);
110 
111   //===------------------------------------------------------------------===//
112   // AA metadata.
113   //===------------------------------------------------------------------===//
114 
115 protected:
116   /// Return metadata appropriate for a AA root node (scope or TBAA).
117   /// Each returned node is distinct from all other metadata and will never
118   /// be identified (uniqued) with anything else.
119   MDNode *createAnonymousAARoot(StringRef Name = StringRef(),
120                                 MDNode *Extra = nullptr);
121 
122 public:
123   /// Return metadata appropriate for a TBAA root node. Each returned
124   /// node is distinct from all other metadata and will never be identified
125   /// (uniqued) with anything else.
126   MDNode *createAnonymousTBAARoot() {
127     return createAnonymousAARoot();
128   }
129 
130   /// Return metadata appropriate for an alias scope domain node.
131   /// Each returned node is distinct from all other metadata and will never
132   /// be identified (uniqued) with anything else.
133   MDNode *createAnonymousAliasScopeDomain(StringRef Name = StringRef()) {
134     return createAnonymousAARoot(Name);
135   }
136 
137   /// Return metadata appropriate for an alias scope root node.
138   /// Each returned node is distinct from all other metadata and will never
139   /// be identified (uniqued) with anything else.
140   MDNode *createAnonymousAliasScope(MDNode *Domain,
141                                     StringRef Name = StringRef()) {
142     return createAnonymousAARoot(Name, Domain);
143   }
144 
145   /// Return metadata appropriate for a TBAA root node with the given
146   /// name.  This may be identified (uniqued) with other roots with the same
147   /// name.
148   MDNode *createTBAARoot(StringRef Name);
149 
150   /// Return metadata appropriate for an alias scope domain node with
151   /// the given name. This may be identified (uniqued) with other roots with
152   /// the same name.
153   MDNode *createAliasScopeDomain(StringRef Name);
154 
155   /// Return metadata appropriate for an alias scope node with
156   /// the given name. This may be identified (uniqued) with other scopes with
157   /// the same name and domain.
158   MDNode *createAliasScope(StringRef Name, MDNode *Domain);
159 
160   /// Return metadata for a non-root TBAA node with the given name,
161   /// parent in the TBAA tree, and value for 'pointsToConstantMemory'.
162   MDNode *createTBAANode(StringRef Name, MDNode *Parent,
163                          bool isConstant = false);
164 
165   struct TBAAStructField {
166     uint64_t Offset;
167     uint64_t Size;
168     MDNode *Type;
169     TBAAStructField(uint64_t Offset, uint64_t Size, MDNode *Type) :
170       Offset(Offset), Size(Size), Type(Type) {}
171   };
172 
173   /// Return metadata for a tbaa.struct node with the given
174   /// struct field descriptions.
175   MDNode *createTBAAStructNode(ArrayRef<TBAAStructField> Fields);
176 
177   /// Return metadata for a TBAA struct node in the type DAG
178   /// with the given name, a list of pairs (offset, field type in the type DAG).
179   MDNode *
180   createTBAAStructTypeNode(StringRef Name,
181                            ArrayRef<std::pair<MDNode *, uint64_t>> Fields);
182 
183   /// Return metadata for a TBAA scalar type node with the
184   /// given name, an offset and a parent in the TBAA type DAG.
185   MDNode *createTBAAScalarTypeNode(StringRef Name, MDNode *Parent,
186                                    uint64_t Offset = 0);
187 
188   /// Return metadata for a TBAA tag node with the given
189   /// base type, access type and offset relative to the base type.
190   MDNode *createTBAAStructTagNode(MDNode *BaseType, MDNode *AccessType,
191                                   uint64_t Offset, bool IsConstant = false);
192 
193   /// Return metadata for a TBAA type node in the TBAA type DAG with the
194   /// given parent type, size in bytes, type identifier and a list of fields.
195   MDNode *createTBAATypeNode(MDNode *Parent, uint64_t Size, Metadata *Id,
196                              ArrayRef<TBAAStructField> Fields =
197                                  ArrayRef<TBAAStructField>());
198 
199   /// Return metadata for a TBAA access tag with the given base type,
200   /// final access type, offset of the access relative to the base type, size of
201   /// the access and flag indicating whether the accessed object can be
202   /// considered immutable for the purposes of the TBAA analysis.
203   MDNode *createTBAAAccessTag(MDNode *BaseType, MDNode *AccessType,
204                               uint64_t Offset, uint64_t Size,
205                               bool IsImmutable = false);
206 
207   /// Return mutable version of the given mutable or immutable TBAA
208   /// access tag.
209   MDNode *createMutableTBAAAccessTag(MDNode *Tag);
210 
211   /// Return metadata containing an irreducible loop header weight.
212   MDNode *createIrrLoopHeaderWeight(uint64_t Weight);
213 };
214 
215 } // end namespace llvm
216 
217 #endif
218