145 lines
4.7 KiB
C++
145 lines
4.7 KiB
C++
//===- SetTheory.h - Generate ordered sets from DAG expressions -*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the SetTheory class that computes ordered sets of
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// Records from DAG expressions. Operators for standard set operations are
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// predefined, and it is possible to add special purpose set operators as well.
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//
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// The user may define named sets as Records of predefined classes. Set
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// expanders can be added to a SetTheory instance to teach it how to find the
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// elements of such a named set.
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//
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// These are the predefined operators. The argument lists can be individual
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// elements (defs), other sets (defs of expandable classes), lists, or DAG
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// expressions that are evaluated recursively.
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//
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// - (add S1, S2 ...) Union sets. This is also how sets are created from element
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// lists.
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//
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// - (sub S1, S2, ...) Set difference. Every element in S1 except for the
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// elements in S2, ...
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//
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// - (and S1, S2) Set intersection. Every element in S1 that is also in S2.
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//
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// - (shl S, N) Shift left. Remove the first N elements from S.
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//
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// - (trunc S, N) Truncate. The first N elements of S.
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//
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// - (rotl S, N) Rotate left. Same as (add (shl S, N), (trunc S, N)).
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//
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// - (rotr S, N) Rotate right.
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//
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// - (decimate S, N) Decimate S by picking every N'th element, starting with
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// the first one. For instance, (decimate S, 2) returns the even elements of
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// S.
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//
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// - (sequence "Format", From, To) Generate a sequence of defs with printf.
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// For instance, (sequence "R%u", 0, 3) -> [ R0, R1, R2, R3 ]
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TABLEGEN_SETTHEORY_H
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#define LLVM_TABLEGEN_SETTHEORY_H
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/ADT/SetVector.h"
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#include "llvm/ADT/StringMap.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/Support/SMLoc.h"
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#include <map>
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#include <memory>
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#include <vector>
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namespace llvm {
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class DagInit;
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class Init;
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class Record;
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class SetTheory {
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public:
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using RecVec = std::vector<Record *>;
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using RecSet = SmallSetVector<Record *, 16>;
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/// Operator - A callback representing a DAG operator.
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class Operator {
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virtual void anchor();
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public:
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virtual ~Operator() = default;
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/// apply - Apply this operator to Expr's arguments and insert the result
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/// in Elts.
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virtual void apply(SetTheory&, DagInit *Expr, RecSet &Elts,
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ArrayRef<SMLoc> Loc) = 0;
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};
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/// Expander - A callback function that can transform a Record representing a
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/// set into a fully expanded list of elements. Expanders provide a way for
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/// users to define named sets that can be used in DAG expressions.
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class Expander {
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virtual void anchor();
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public:
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virtual ~Expander() = default;
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virtual void expand(SetTheory&, Record*, RecSet &Elts) = 0;
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};
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private:
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// Map set defs to their fully expanded contents. This serves as a memoization
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// cache and it makes it possible to return const references on queries.
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using ExpandMap = std::map<Record *, RecVec>;
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ExpandMap Expansions;
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// Known DAG operators by name.
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StringMap<std::unique_ptr<Operator>> Operators;
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// Typed expanders by class name.
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StringMap<std::unique_ptr<Expander>> Expanders;
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public:
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/// Create a SetTheory instance with only the standard operators.
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SetTheory();
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/// addExpander - Add an expander for Records with the named super class.
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void addExpander(StringRef ClassName, std::unique_ptr<Expander>);
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/// addFieldExpander - Add an expander for ClassName that simply evaluates
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/// FieldName in the Record to get the set elements. That is all that is
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/// needed for a class like:
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///
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/// class Set<dag d> {
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/// dag Elts = d;
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/// }
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///
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void addFieldExpander(StringRef ClassName, StringRef FieldName);
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/// addOperator - Add a DAG operator.
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void addOperator(StringRef Name, std::unique_ptr<Operator>);
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/// evaluate - Evaluate Expr and append the resulting set to Elts.
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void evaluate(Init *Expr, RecSet &Elts, ArrayRef<SMLoc> Loc);
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/// evaluate - Evaluate a sequence of Inits and append to Elts.
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template<typename Iter>
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void evaluate(Iter begin, Iter end, RecSet &Elts, ArrayRef<SMLoc> Loc) {
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while (begin != end)
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evaluate(*begin++, Elts, Loc);
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}
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/// expand - Expand a record into a set of elements if possible. Return a
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/// pointer to the expanded elements, or NULL if Set cannot be expanded
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/// further.
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const RecVec *expand(Record *Set);
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};
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} // end namespace llvm
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#endif // LLVM_TABLEGEN_SETTHEORY_H
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