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SetTheory.h
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1 //===- SetTheory.h - Generate ordered sets from DAG expressions -*- 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 implements the SetTheory class that computes ordered sets of
10 // Records from DAG expressions. Operators for standard set operations are
11 // predefined, and it is possible to add special purpose set operators as well.
12 //
13 // The user may define named sets as Records of predefined classes. Set
14 // expanders can be added to a SetTheory instance to teach it how to find the
15 // elements of such a named set.
16 //
17 // These are the predefined operators. The argument lists can be individual
18 // elements (defs), other sets (defs of expandable classes), lists, or DAG
19 // expressions that are evaluated recursively.
20 //
21 // - (add S1, S2 ...) Union sets. This is also how sets are created from element
22 // lists.
23 //
24 // - (sub S1, S2, ...) Set difference. Every element in S1 except for the
25 // elements in S2, ...
26 //
27 // - (and S1, S2) Set intersection. Every element in S1 that is also in S2.
28 //
29 // - (shl S, N) Shift left. Remove the first N elements from S.
30 //
31 // - (trunc S, N) Truncate. The first N elements of S.
32 //
33 // - (rotl S, N) Rotate left. Same as (add (shl S, N), (trunc S, N)).
34 //
35 // - (rotr S, N) Rotate right.
36 //
37 // - (decimate S, N) Decimate S by picking every N'th element, starting with
38 // the first one. For instance, (decimate S, 2) returns the even elements of
39 // S.
40 //
41 // - (sequence "Format", From, To) Generate a sequence of defs with printf.
42 // For instance, (sequence "R%u", 0, 3) -> [ R0, R1, R2, R3 ]
43 //
44 //===----------------------------------------------------------------------===//
45 
46 #ifndef LLVM_TABLEGEN_SETTHEORY_H
47 #define LLVM_TABLEGEN_SETTHEORY_H
48 
49 #include "llvm/ADT/ArrayRef.h"
50 #include "llvm/ADT/SetVector.h"
51 #include "llvm/ADT/StringMap.h"
52 #include "llvm/ADT/StringRef.h"
53 #include "llvm/Support/SMLoc.h"
54 #include <map>
55 #include <memory>
56 #include <vector>
57 
58 namespace llvm {
59 
60 class DagInit;
61 class Init;
62 class Record;
63 
64 class SetTheory {
65 public:
66  using RecVec = std::vector<Record *>;
68 
69  /// Operator - A callback representing a DAG operator.
70  class Operator {
71  virtual void anchor();
72 
73  public:
74  virtual ~Operator() = default;
75 
76  /// apply - Apply this operator to Expr's arguments and insert the result
77  /// in Elts.
78  virtual void apply(SetTheory&, DagInit *Expr, RecSet &Elts,
79  ArrayRef<SMLoc> Loc) = 0;
80  };
81 
82  /// Expander - A callback function that can transform a Record representing a
83  /// set into a fully expanded list of elements. Expanders provide a way for
84  /// users to define named sets that can be used in DAG expressions.
85  class Expander {
86  virtual void anchor();
87 
88  public:
89  virtual ~Expander() = default;
90 
91  virtual void expand(SetTheory&, Record*, RecSet &Elts) = 0;
92  };
93 
94 private:
95  // Map set defs to their fully expanded contents. This serves as a memoization
96  // cache and it makes it possible to return const references on queries.
97  using ExpandMap = std::map<Record *, RecVec>;
98  ExpandMap Expansions;
99 
100  // Known DAG operators by name.
102 
103  // Typed expanders by class name.
105 
106 public:
107  /// Create a SetTheory instance with only the standard operators.
108  SetTheory();
109 
110  /// addExpander - Add an expander for Records with the named super class.
111  void addExpander(StringRef ClassName, std::unique_ptr<Expander>);
112 
113  /// addFieldExpander - Add an expander for ClassName that simply evaluates
114  /// FieldName in the Record to get the set elements. That is all that is
115  /// needed for a class like:
116  ///
117  /// class Set<dag d> {
118  /// dag Elts = d;
119  /// }
120  ///
121  void addFieldExpander(StringRef ClassName, StringRef FieldName);
122 
123  /// addOperator - Add a DAG operator.
124  void addOperator(StringRef Name, std::unique_ptr<Operator>);
125 
126  /// evaluate - Evaluate Expr and append the resulting set to Elts.
127  void evaluate(Init *Expr, RecSet &Elts, ArrayRef<SMLoc> Loc);
128 
129  /// evaluate - Evaluate a sequence of Inits and append to Elts.
130  template<typename Iter>
131  void evaluate(Iter begin, Iter end, RecSet &Elts, ArrayRef<SMLoc> Loc) {
132  while (begin != end)
133  evaluate(*begin++, Elts, Loc);
134  }
135 
136  /// expand - Expand a record into a set of elements if possible. Return a
137  /// pointer to the expanded elements, or NULL if Set cannot be expanded
138  /// further.
139  const RecVec *expand(Record *Set);
140 };
141 
142 } // end namespace llvm
143 
144 #endif // LLVM_TABLEGEN_SETTHEORY_H
const_iterator end(StringRef path)
Get end iterator over path.
Definition: Path.cpp:233
const_iterator begin(StringRef path, Style style=Style::native)
Get begin iterator over path.
Definition: Path.cpp:224
This class represents lattice values for constants.
Definition: AllocatorList.h:23
Operator - A callback representing a DAG operator.
Definition: SetTheory.h:70
amdgpu Simplify well known AMD library false FunctionCallee Value const Twine & Name
SetTheory()
Create a SetTheory instance with only the standard operators.
Definition: SetTheory.cpp:257
Expander - A callback function that can transform a Record representing a set into a fully expanded l...
Definition: SetTheory.h:85
void evaluate(Iter begin, Iter end, RecSet &Elts, ArrayRef< SMLoc > Loc)
evaluate - Evaluate a sequence of Inits and append to Elts.
Definition: SetTheory.h:131
virtual ~Operator()=default
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory)...
Definition: APInt.h:32
void addFieldExpander(StringRef ClassName, StringRef FieldName)
addFieldExpander - Add an expander for ClassName that simply evaluates FieldName in the Record to get...
Definition: SetTheory.cpp:278
A SetVector that performs no allocations if smaller than a certain size.
Definition: SetVector.h:297
void addExpander(StringRef ClassName, std::unique_ptr< Expander >)
addExpander - Add an expander for Records with the named super class.
Definition: SetTheory.cpp:274
virtual void apply(SetTheory &, DagInit *Expr, RecSet &Elts, ArrayRef< SMLoc > Loc)=0
apply - Apply this operator to Expr&#39;s arguments and insert the result in Elts.
void addOperator(StringRef Name, std::unique_ptr< Operator >)
addOperator - Add a DAG operator.
Definition: SetTheory.cpp:270
StringMap - This is an unconventional map that is specialized for handling keys that are "strings"...
Definition: StringMap.h:242
const RecVec * expand(Record *Set)
expand - Expand a record into a set of elements if possible.
Definition: SetTheory.cpp:308
std::vector< Record * > RecVec
Definition: SetTheory.h:66
(v a, b) - Represent a DAG tree value.
Definition: Record.h:1302
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:48
void evaluate(Init *Expr, RecSet &Elts, ArrayRef< SMLoc > Loc)
evaluate - Evaluate Expr and append the resulting set to Elts.
Definition: SetTheory.cpp:282