Add an implementation of the delta debugging algorithm.

 - This is a pretty slow / memory intensive implementation, and I will likely
   change it to an iterative model, but it works.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90447 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 96 insertions, 0 deletions

diff --git a/unittests/ADT/DeltaAlgorithmTest.cpp b/unittests/ADT/DeltaAlgorithmTest.cpp
new file mode 100644
index 0000000000..362892207f
--- /dev/null
+++ b/unittests/ADT/DeltaAlgorithmTest.cpp
@@ -0,0 +1,96 @@
+//===- llvm/unittest/ADT/DeltaAlgorithmTest.cpp ---------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "gtest/gtest.h"
+#include "llvm/ADT/DeltaAlgorithm.h"
+#include <algorithm>
+#include <cstdarg>
+using namespace llvm;
+
+std::ostream &operator<<(std::ostream &OS,
+                         const std::set<unsigned> &S) {
+  OS << "{";
+  for (std::set<unsigned>::const_iterator it = S.begin(),
+         ie = S.end(); it != ie; ++it) {
+    if (it != S.begin())
+      OS << ",";
+    OS << *it;
+  }
+  OS << "}";
+  return OS;
+}
+
+namespace {
+
+class FixedDeltaAlgorithm : public DeltaAlgorithm {
+  changeset_ty FailingSet;
+  unsigned NumTests;
+
+protected:
+  virtual bool ExecuteOneTest(const changeset_ty &Changes) {
+    ++NumTests;
+    return std::includes(Changes.begin(), Changes.end(),
+                         FailingSet.begin(), FailingSet.end());
+  }
+
+public:
+  FixedDeltaAlgorithm(const changeset_ty &_FailingSet)
+    : FailingSet(_FailingSet),
+      NumTests(0) {}
+
+  unsigned getNumTests() const { return NumTests; }
+};
+
+std::set<unsigned> fixed_set(unsigned N, ...) {
+  std::set<unsigned> S;
+  va_list ap;
+  va_start(ap, N);
+  for (unsigned i = 0; i != N; ++i)
+    S.insert(va_arg(ap, unsigned));
+  va_end(ap);
+  return S;
+}
+
+std::set<unsigned> range(unsigned Start, unsigned End) {
+  std::set<unsigned> S;
+  while (Start != End)
+    S.insert(Start++);
+  return S;
+}
+
+std::set<unsigned> range(unsigned N) {
+  return range(0, N);
+}
+
+TEST(DeltaAlgorithmTest, Basic) {
+  // P = {3,5,7} \in S
+  //   [0, 20) should minimize to {3,5,7} in a reasonable number of tests.
+  std::set<unsigned> Fails = fixed_set(3, 3, 5, 7);
+  FixedDeltaAlgorithm FDA(Fails);
+  EXPECT_EQ(fixed_set(3, 3, 5, 7), FDA.Run(range(20)));
+  EXPECT_GE(33U, FDA.getNumTests());
+
+  // P = {3,5,7} \in S
+  //   [10, 20) should minimize to [10,20)
+  EXPECT_EQ(range(10,20), FDA.Run(range(10,20)));
+
+  // P = [0,4) \in S
+  //   [0, 4) should minimize to [0,4) in 11 tests.
+  //
+  // 11 = |{ {},
+  //         {0}, {1}, {2}, {3},
+  //         {1, 2, 3}, {0, 2, 3}, {0, 1, 3}, {0, 1, 2}, 
+  //         {0, 1}, {2, 3} }|
+  FDA = FixedDeltaAlgorithm(range(10));
+  EXPECT_EQ(range(4), FDA.Run(range(4)));
+  EXPECT_EQ(11U, FDA.getNumTests());  
+}
+
+}
+