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/SmallVector.h"
19 #include "llvm/ADT/StringRef.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 Function;
32 class MDNode;
33 class MDString;
34 class Metadata;
35 
36 class MDBuilder {
37   LLVMContext &Context;
38 
39 public:
40   MDBuilder(LLVMContext &context) : Context(context) {}
41 
42   /// Return the given string as metadata.
43   MDString *createString(StringRef Str);
44 
45   /// Return the given constant as metadata.
46   ConstantAsMetadata *createConstant(Constant *C);
47 
48   //===------------------------------------------------------------------===//
49   // FPMath metadata.
50   //===------------------------------------------------------------------===//
51 
52   /// Return metadata with the given settings.  The special value 0.0
53   /// for the Accuracy parameter indicates the default (maximal precision)
54   /// setting.
55   MDNode *createFPMath(float Accuracy);
56 
57   //===------------------------------------------------------------------===//
58   // Prof metadata.
59   //===------------------------------------------------------------------===//
60 
61   /// Return metadata containing two branch weights.
62   MDNode *createBranchWeights(uint32_t TrueWeight, uint32_t FalseWeight);
63 
64   /// Return metadata containing a number of branch weights.
65   MDNode *createBranchWeights(ArrayRef<uint32_t> Weights);
66 
67   /// Return metadata specifying that a branch or switch is unpredictable.
68   MDNode *createUnpredictable();
69 
70   /// Return metadata containing the entry \p Count for a function, a boolean
71   /// \Synthetic indicating whether the counts were synthetized, and the
72   /// GUIDs stored in \p Imports that need to be imported for sample PGO, to
73   /// enable the same inlines as the profiled optimized binary
74   MDNode *createFunctionEntryCount(uint64_t Count, bool Synthetic,
75                                    const DenseSet<GlobalValue::GUID> *Imports);
76 
77   /// Return metadata containing the section prefix for a function.
78   MDNode *createFunctionSectionPrefix(StringRef Prefix);
79 
80   /// Return metadata containing the pseudo probe descriptor for a function.
81   MDNode *createPseudoProbeDesc(uint64_t GUID, uint64_t Hash, StringRef FName);
82 
83   /// Return metadata containing llvm statistics.
84   MDNode *
85   createLLVMStats(ArrayRef<std::pair<StringRef, uint64_t>> LLVMStatsVec);
86 
87   //===------------------------------------------------------------------===//
88   // Range metadata.
89   //===------------------------------------------------------------------===//
90 
91   /// Return metadata describing the range [Lo, Hi).
92   MDNode *createRange(const APInt &Lo, const APInt &Hi);
93 
94   /// Return metadata describing the range [Lo, Hi).
95   MDNode *createRange(Constant *Lo, Constant *Hi);
96 
97   //===------------------------------------------------------------------===//
98   // Callees metadata.
99   //===------------------------------------------------------------------===//
100 
101   /// Return metadata indicating the possible callees of indirect
102   /// calls.
103   MDNode *createCallees(ArrayRef<Function *> Callees);
104 
105   //===------------------------------------------------------------------===//
106   // Callback metadata.
107   //===------------------------------------------------------------------===//
108 
109   /// Return metadata describing a callback (see llvm::AbstractCallSite).
110   MDNode *createCallbackEncoding(unsigned CalleeArgNo, ArrayRef<int> Arguments,
111                                  bool VarArgsArePassed);
112 
113   /// Merge the new callback encoding \p NewCB into \p ExistingCallbacks.
114   MDNode *mergeCallbackEncodings(MDNode *ExistingCallbacks, MDNode *NewCB);
115 
116   /// Return metadata feeding to the CodeGen about how to generate a function
117   /// prologue for the "function" santizier.
118   MDNode *createRTTIPointerPrologue(Constant *PrologueSig, Constant *RTTI);
119 
120   //===------------------------------------------------------------------===//
121   // PC sections metadata.
122   //===------------------------------------------------------------------===//
123 
124   /// A pair of PC section name with auxilliary constant data.
125   using PCSection = std::pair<StringRef, SmallVector<Constant *>>;
126 
127   /// Return metadata for PC sections.
128   MDNode *createPCSections(ArrayRef<PCSection> Sections);
129 
130   //===------------------------------------------------------------------===//
131   // AA metadata.
132   //===------------------------------------------------------------------===//
133 
134 protected:
135   /// Return metadata appropriate for a AA root node (scope or TBAA).
136   /// Each returned node is distinct from all other metadata and will never
137   /// be identified (uniqued) with anything else.
138   MDNode *createAnonymousAARoot(StringRef Name = StringRef(),
139                                 MDNode *Extra = nullptr);
140 
141 public:
142   /// Return metadata appropriate for a TBAA root node. Each returned
143   /// node is distinct from all other metadata and will never be identified
144   /// (uniqued) with anything else.
145   MDNode *createAnonymousTBAARoot() {
146     return createAnonymousAARoot();
147   }
148 
149   /// Return metadata appropriate for an alias scope domain node.
150   /// Each returned node is distinct from all other metadata and will never
151   /// be identified (uniqued) with anything else.
152   MDNode *createAnonymousAliasScopeDomain(StringRef Name = StringRef()) {
153     return createAnonymousAARoot(Name);
154   }
155 
156   /// Return metadata appropriate for an alias scope root node.
157   /// Each returned node is distinct from all other metadata and will never
158   /// be identified (uniqued) with anything else.
159   MDNode *createAnonymousAliasScope(MDNode *Domain,
160                                     StringRef Name = StringRef()) {
161     return createAnonymousAARoot(Name, Domain);
162   }
163 
164   /// Return metadata appropriate for a TBAA root node with the given
165   /// name.  This may be identified (uniqued) with other roots with the same
166   /// name.
167   MDNode *createTBAARoot(StringRef Name);
168 
169   /// Return metadata appropriate for an alias scope domain node with
170   /// the given name. This may be identified (uniqued) with other roots with
171   /// the same name.
172   MDNode *createAliasScopeDomain(StringRef Name);
173 
174   /// Return metadata appropriate for an alias scope node with
175   /// the given name. This may be identified (uniqued) with other scopes with
176   /// the same name and domain.
177   MDNode *createAliasScope(StringRef Name, MDNode *Domain);
178 
179   /// Return metadata for a non-root TBAA node with the given name,
180   /// parent in the TBAA tree, and value for 'pointsToConstantMemory'.
181   MDNode *createTBAANode(StringRef Name, MDNode *Parent,
182                          bool isConstant = false);
183 
184   struct TBAAStructField {
185     uint64_t Offset;
186     uint64_t Size;
187     MDNode *Type;
188     TBAAStructField(uint64_t Offset, uint64_t Size, MDNode *Type) :
189       Offset(Offset), Size(Size), Type(Type) {}
190   };
191 
192   /// Return metadata for a tbaa.struct node with the given
193   /// struct field descriptions.
194   MDNode *createTBAAStructNode(ArrayRef<TBAAStructField> Fields);
195 
196   /// Return metadata for a TBAA struct node in the type DAG
197   /// with the given name, a list of pairs (offset, field type in the type DAG).
198   MDNode *
199   createTBAAStructTypeNode(StringRef Name,
200                            ArrayRef<std::pair<MDNode *, uint64_t>> Fields);
201 
202   /// Return metadata for a TBAA scalar type node with the
203   /// given name, an offset and a parent in the TBAA type DAG.
204   MDNode *createTBAAScalarTypeNode(StringRef Name, MDNode *Parent,
205                                    uint64_t Offset = 0);
206 
207   /// Return metadata for a TBAA tag node with the given
208   /// base type, access type and offset relative to the base type.
209   MDNode *createTBAAStructTagNode(MDNode *BaseType, MDNode *AccessType,
210                                   uint64_t Offset, bool IsConstant = false);
211 
212   /// Return metadata for a TBAA type node in the TBAA type DAG with the
213   /// given parent type, size in bytes, type identifier and a list of fields.
214   MDNode *createTBAATypeNode(MDNode *Parent, uint64_t Size, Metadata *Id,
215                              ArrayRef<TBAAStructField> Fields =
216                                  ArrayRef<TBAAStructField>());
217 
218   /// Return metadata for a TBAA access tag with the given base type,
219   /// final access type, offset of the access relative to the base type, size of
220   /// the access and flag indicating whether the accessed object can be
221   /// considered immutable for the purposes of the TBAA analysis.
222   MDNode *createTBAAAccessTag(MDNode *BaseType, MDNode *AccessType,
223                               uint64_t Offset, uint64_t Size,
224                               bool IsImmutable = false);
225 
226   /// Return mutable version of the given mutable or immutable TBAA
227   /// access tag.
228   MDNode *createMutableTBAAAccessTag(MDNode *Tag);
229 
230   /// Return metadata containing an irreducible loop header weight.
231   MDNode *createIrrLoopHeaderWeight(uint64_t Weight);
232 };
233 
234 } // end namespace llvm
235 
236 #endif
237