/3rd_party/llvm/lib/Support/DeltaAlgorithm.cpp
https://code.google.com/p/softart/ · C++ · 114 lines · 76 code · 18 blank · 20 comment · 18 complexity · 56af99590ed9b9b4d618490972f5f0d5 MD5 · raw file
- //===--- DeltaAlgorithm.cpp - A Set Minimization Algorithm -----*- C++ -*--===//
- //
- // The LLVM Compiler Infrastructure
- //
- // This file is distributed under the University of Illinois Open Source
- // License. See LICENSE.TXT for details.
- //===----------------------------------------------------------------------===//
- #include "llvm/ADT/DeltaAlgorithm.h"
- #include <algorithm>
- #include <iterator>
- using namespace llvm;
- DeltaAlgorithm::~DeltaAlgorithm() {
- }
- bool DeltaAlgorithm::GetTestResult(const changeset_ty &Changes) {
- if (FailedTestsCache.count(Changes))
- return false;
- bool Result = ExecuteOneTest(Changes);
- if (!Result)
- FailedTestsCache.insert(Changes);
- return Result;
- }
- void DeltaAlgorithm::Split(const changeset_ty &S, changesetlist_ty &Res) {
- // FIXME: Allow clients to provide heuristics for improved splitting.
- // FIXME: This is really slow.
- changeset_ty LHS, RHS;
- unsigned idx = 0, N = S.size() / 2;
- for (changeset_ty::const_iterator it = S.begin(),
- ie = S.end(); it != ie; ++it, ++idx)
- ((idx < N) ? LHS : RHS).insert(*it);
- if (!LHS.empty())
- Res.push_back(LHS);
- if (!RHS.empty())
- Res.push_back(RHS);
- }
- DeltaAlgorithm::changeset_ty
- DeltaAlgorithm::Delta(const changeset_ty &Changes,
- const changesetlist_ty &Sets) {
- // Invariant: union(Res) == Changes
- UpdatedSearchState(Changes, Sets);
- // If there is nothing left we can remove, we are done.
- if (Sets.size() <= 1)
- return Changes;
- // Look for a passing subset.
- changeset_ty Res;
- if (Search(Changes, Sets, Res))
- return Res;
- // Otherwise, partition the sets if possible; if not we are done.
- changesetlist_ty SplitSets;
- for (changesetlist_ty::const_iterator it = Sets.begin(),
- ie = Sets.end(); it != ie; ++it)
- Split(*it, SplitSets);
- if (SplitSets.size() == Sets.size())
- return Changes;
- return Delta(Changes, SplitSets);
- }
- bool DeltaAlgorithm::Search(const changeset_ty &Changes,
- const changesetlist_ty &Sets,
- changeset_ty &Res) {
- // FIXME: Parallelize.
- for (changesetlist_ty::const_iterator it = Sets.begin(),
- ie = Sets.end(); it != ie; ++it) {
- // If the test passes on this subset alone, recurse.
- if (GetTestResult(*it)) {
- changesetlist_ty Sets;
- Split(*it, Sets);
- Res = Delta(*it, Sets);
- return true;
- }
- // Otherwise, if we have more than two sets, see if test passes on the
- // complement.
- if (Sets.size() > 2) {
- // FIXME: This is really slow.
- changeset_ty Complement;
- std::set_difference(
- Changes.begin(), Changes.end(), it->begin(), it->end(),
- std::insert_iterator<changeset_ty>(Complement, Complement.begin()));
- if (GetTestResult(Complement)) {
- changesetlist_ty ComplementSets;
- ComplementSets.insert(ComplementSets.end(), Sets.begin(), it);
- ComplementSets.insert(ComplementSets.end(), it + 1, Sets.end());
- Res = Delta(Complement, ComplementSets);
- return true;
- }
- }
- }
- return false;
- }
- DeltaAlgorithm::changeset_ty DeltaAlgorithm::Run(const changeset_ty &Changes) {
- // Check empty set first to quickly find poor test functions.
- if (GetTestResult(changeset_ty()))
- return changeset_ty();
- // Otherwise run the real delta algorithm.
- changesetlist_ty Sets;
- Split(Changes, Sets);
- return Delta(Changes, Sets);
- }