freebsd-skq/contrib/llvm/lib/Support/DeltaAlgorithm.cpp
ed b9a7e30aff Upgrade our Clang in base to r108428.
This commit merges the latest LLVM sources from the vendor space. It
also updates the build glue to match the new sources. Clang's version
number is changed to match LLVM's, which means /usr/include/clang/2.0
has been renamed to /usr/include/clang/2.8.

Obtained from:	projects/clangbsd
2010-07-20 17:16:57 +00:00

115 lines
3.4 KiB
C++

//===--- 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);
}