1//===- MemoryModelRelaxationAnnotations.h -----------------------*- 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/// \file
10/// This file provides utility for Memory Model Relaxation Annotations (MMRAs).
11/// Those annotations are represented using Metadata. The MMRATagSet class
12/// offers a simple API to parse the metadata and perform common operations on
13/// it. The MMRAMetadata class is a simple tuple of MDNode that provides easy
14/// access to all MMRA annotations on an instruction.
15//
16//===----------------------------------------------------------------------===//
17
18#ifndef LLVM_IR_MEMORYMODELRELAXATIONANNOTATIONS_H
19#define LLVM_IR_MEMORYMODELRELAXATIONANNOTATIONS_H
20
21#include "llvm/ADT/DenseSet.h"
22#include "llvm/ADT/StringRef.h"
23#include <tuple> // for std::pair
24
25namespace llvm {
26
27template <typename T> class ArrayRef;
28
29class MDNode;
30class MDTuple;
31class Metadata;
32class raw_ostream;
33class LLVMContext;
34class Instruction;
35
36/// Helper class to manipulate `!mmra` metadata nodes.
37///
38/// This can be visualized as a set of "tags", with each tag
39/// representing a particular property of an instruction, as
40/// explained in the MemoryModelRelaxationAnnotations docs.
41///
42/// This class (and the optimizer in general) does not reason
43/// about the exact nature of the tags and the properties they
44/// imply. It just sees the metadata as a collection of tags, which
45/// are a prefix/suffix pair of strings.
46class MMRAMetadata {
47public:
48 using TagT = std::pair<StringRef, StringRef>;
49 using SetT = DenseSet<TagT>;
50 using const_iterator = SetT::const_iterator;
51
52 /// \name Constructors
53 /// @{
54 MMRAMetadata() = default;
55 MMRAMetadata(const Instruction &I);
56 MMRAMetadata(MDNode *MD);
57 /// @}
58
59 /// \name Metadata Helpers & Builders
60 /// @{
61
62 /// Combines \p A and \p B according to MMRA semantics.
63 /// \returns !mmra metadata for the combined MMRAs.
64 static MDNode *combine(LLVMContext &Ctx, const MMRAMetadata &A,
65 const MMRAMetadata &B);
66
67 /// Creates !mmra metadata for a single tag.
68 ///
69 /// !mmra metadata can either be a single tag, or a MDTuple containing
70 /// multiple tags.
71 static MDTuple *getTagMD(LLVMContext &Ctx, StringRef Prefix,
72 StringRef Suffix);
73 static MDTuple *getTagMD(LLVMContext &Ctx, const TagT &T) {
74 return getTagMD(Ctx, Prefix: T.first, Suffix: T.second);
75 }
76
77 /// Creates !mmra metadata from \p Tags.
78 /// \returns nullptr or a MDTuple* from \p Tags.
79 static MDTuple *getMD(LLVMContext &Ctx, ArrayRef<TagT> Tags);
80
81 /// \returns true if \p MD is a well-formed MMRA tag.
82 static bool isTagMD(const Metadata *MD);
83
84 /// @}
85
86 /// \name Compatibility Helpers
87 /// @{
88
89 /// \returns whether the MMRAs on \p A and \p B are compatible.
90 static bool checkCompatibility(const Instruction &A, const Instruction &B) {
91 return MMRAMetadata(A).isCompatibleWith(Other: B);
92 }
93
94 /// \returns whether this set of tags is compatible with \p Other.
95 bool isCompatibleWith(const MMRAMetadata &Other) const;
96
97 /// @}
98
99 /// \name Content Queries
100 /// @{
101
102 bool hasTag(StringRef Prefix, StringRef Suffix) const;
103 bool hasTagWithPrefix(StringRef Prefix) const;
104
105 const_iterator begin() const;
106 const_iterator end() const;
107 bool empty() const;
108 unsigned size() const;
109
110 /// @}
111
112 void print(raw_ostream &OS) const;
113 void dump() const;
114
115 operator bool() const { return !Tags.empty(); }
116 bool operator==(const MMRAMetadata &Other) const {
117 return Tags == Other.Tags;
118 }
119 bool operator!=(const MMRAMetadata &Other) const {
120 return Tags != Other.Tags;
121 }
122
123private:
124 SetT Tags;
125};
126
127/// \returns true if \p I can have !mmra metadata.
128bool canInstructionHaveMMRAs(const Instruction &I);
129
130} // namespace llvm
131
132#endif
133