1 //===- SetTheory.h - Generate ordered sets from DAG expressions -*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the SetTheory class that computes ordered sets of
11 // Records from DAG expressions. Operators for standard set operations are
12 // predefined, and it is possible to add special purpose set operators as well.
14 // The user may define named sets as Records of predefined classes. Set
15 // expanders can be added to a SetTheory instance to teach it how to find the
16 // elements of such a named set.
18 // These are the predefined operators. The argument lists can be individual
19 // elements (defs), other sets (defs of expandable classes), lists, or DAG
20 // expressions that are evaluated recursively.
22 // - (add S1, S2 ...) Union sets. This is also how sets are created from element
25 // - (sub S1, S2, ...) Set difference. Every element in S1 except for the
26 // elements in S2, ...
28 // - (and S1, S2) Set intersection. Every element in S1 that is also in S2.
30 // - (shl S, N) Shift left. Remove the first N elements from S.
32 // - (trunc S, N) Truncate. The first N elements of S.
34 // - (rotl S, N) Rotate left. Same as (add (shl S, N), (trunc S, N)).
36 // - (rotr S, N) Rotate right.
38 // - (decimate S, N) Decimate S by picking every N'th element, starting with
39 // the first one. For instance, (decimate S, 2) returns the even elements of
42 // - (sequence "Format", From, To) Generate a sequence of defs with printf.
43 // For instance, (sequence "R%u", 0, 3) -> [ R0, R1, R2, R3 ]
45 //===----------------------------------------------------------------------===//
47 #ifndef LLVM_TABLEGEN_SETTHEORY_H
48 #define LLVM_TABLEGEN_SETTHEORY_H
50 #include "llvm/ADT/ArrayRef.h"
51 #include "llvm/ADT/SetVector.h"
52 #include "llvm/ADT/StringMap.h"
53 #include "llvm/ADT/StringRef.h"
54 #include "llvm/Support/SMLoc.h"
67 using RecVec = std::vector<Record *>;
68 using RecSet = SmallSetVector<Record *, 16>;
70 /// Operator - A callback representing a DAG operator.
72 virtual void anchor();
75 virtual ~Operator() = default;
77 /// apply - Apply this operator to Expr's arguments and insert the result
79 virtual void apply(SetTheory&, DagInit *Expr, RecSet &Elts,
80 ArrayRef<SMLoc> Loc) = 0;
83 /// Expander - A callback function that can transform a Record representing a
84 /// set into a fully expanded list of elements. Expanders provide a way for
85 /// users to define named sets that can be used in DAG expressions.
87 virtual void anchor();
90 virtual ~Expander() = default;
92 virtual void expand(SetTheory&, Record*, RecSet &Elts) = 0;
96 // Map set defs to their fully expanded contents. This serves as a memoization
97 // cache and it makes it possible to return const references on queries.
98 using ExpandMap = std::map<Record *, RecVec>;
101 // Known DAG operators by name.
102 StringMap<std::unique_ptr<Operator>> Operators;
104 // Typed expanders by class name.
105 StringMap<std::unique_ptr<Expander>> Expanders;
108 /// Create a SetTheory instance with only the standard operators.
111 /// addExpander - Add an expander for Records with the named super class.
112 void addExpander(StringRef ClassName, std::unique_ptr<Expander>);
114 /// addFieldExpander - Add an expander for ClassName that simply evaluates
115 /// FieldName in the Record to get the set elements. That is all that is
116 /// needed for a class like:
118 /// class Set<dag d> {
122 void addFieldExpander(StringRef ClassName, StringRef FieldName);
124 /// addOperator - Add a DAG operator.
125 void addOperator(StringRef Name, std::unique_ptr<Operator>);
127 /// evaluate - Evaluate Expr and append the resulting set to Elts.
128 void evaluate(Init *Expr, RecSet &Elts, ArrayRef<SMLoc> Loc);
130 /// evaluate - Evaluate a sequence of Inits and append to Elts.
131 template<typename Iter>
132 void evaluate(Iter begin, Iter end, RecSet &Elts, ArrayRef<SMLoc> Loc) {
134 evaluate(*begin++, Elts, Loc);
137 /// expand - Expand a record into a set of elements if possible. Return a
138 /// pointer to the expanded elements, or NULL if Set cannot be expanded
140 const RecVec *expand(Record *Set);
143 } // end namespace llvm
145 #endif // LLVM_TABLEGEN_SETTHEORY_H