76 lines
3.0 KiB
C++
76 lines
3.0 KiB
C++
//===--- DAGDeltaAlgorithm.h - A DAG Minimization Algorithm ----*- C++ -*--===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ADT_DAGDELTAALGORITHM_H
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#define LLVM_ADT_DAGDELTAALGORITHM_H
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#include <vector>
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#include <set>
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namespace llvm {
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/// DAGDeltaAlgorithm - Implements a "delta debugging" algorithm for minimizing
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/// directed acyclic graphs using a predicate function.
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///
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/// The result of the algorithm is a subset of the input change set which is
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/// guaranteed to satisfy the predicate, assuming that the input set did. For
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/// well formed predicates, the result set is guaranteed to be such that
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/// removing any single element not required by the dependencies on the other
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/// elements would falsify the predicate.
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///
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/// The DAG should be used to represent dependencies in the changes which are
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/// likely to hold across the predicate function. That is, for a particular
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/// changeset S and predicate P:
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///
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/// P(S) => P(S union pred(S))
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///
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/// The minization algorithm uses this dependency information to attempt to
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/// eagerly prune large subsets of changes. As with \see DeltaAlgorithm, the DAG
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/// is not required to satisfy this property, but the algorithm will run
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/// substantially fewer tests with appropriate dependencies. \see DeltaAlgorithm
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/// for more information on the properties which the predicate function itself
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/// should satisfy.
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class DAGDeltaAlgorithm {
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public:
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typedef unsigned change_ty;
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typedef std::pair<change_ty, change_ty> edge_ty;
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// FIXME: Use a decent data structure.
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typedef std::set<change_ty> changeset_ty;
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typedef std::vector<changeset_ty> changesetlist_ty;
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public:
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virtual ~DAGDeltaAlgorithm() {}
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/// Run - Minimize the DAG formed by the \arg Changes vertices and the \arg
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/// Dependencies edges by executing \see ExecuteOneTest() on subsets of
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/// changes and returning the smallest set which still satisfies the test
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/// predicate and the input \arg Dependencies.
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///
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/// \param Changes The list of changes.
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///
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/// \param Dependencies The list of dependencies amongst changes. For each
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/// (x,y) in \arg Dependencies, both x and y must be in \arg Changes. The
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/// minimization algorithm guarantees that for each tested changed set S, x
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/// \in S implies y \in S. It is an error to have cyclic dependencies.
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changeset_ty Run(const changeset_ty &Changes,
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const std::vector<edge_ty> &Dependencies);
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/// UpdatedSearchState - Callback used when the search state changes.
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virtual void UpdatedSearchState(const changeset_ty &Changes,
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const changesetlist_ty &Sets,
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const changeset_ty &Required) {}
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/// ExecuteOneTest - Execute a single test predicate on the change set \arg S.
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virtual bool ExecuteOneTest(const changeset_ty &S) = 0;
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};
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} // end namespace llvm
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#endif
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