[llvm-commits] [llvm] r70572 - in /llvm/trunk: include/llvm/ADT/DenseMap.h unittests/ADT/DenseSetTest.cpp

[Stuart Hastings]

Author: stuart
Date: Fri May  1 15:47:53 2009
New Revision: 70572

URL: http://llvm.org/viewvc/llvm-project?rev=70572&view=rev
Log:
Prevent looping when DenseSet is abused.

Added:
    llvm/trunk/unittests/ADT/DenseSetTest.cpp
Modified:
    llvm/trunk/include/llvm/ADT/DenseMap.h

Modified: llvm/trunk/include/llvm/ADT/DenseMap.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/DenseMap.h?rev=70572&r1=70571&r2=70572&view=diff

==============================================================================
--- llvm/trunk/include/llvm/ADT/DenseMap.h (original)
+++ llvm/trunk/include/llvm/ADT/DenseMap.h Fri May  1 15:47:53 2009
@@ -346,12 +346,12 @@
     // probe almost the entire table until it found the empty bucket.  If the
     // table completely filled with tombstones, no lookup would ever succeed,
     // causing infinite loops in lookup.
+    ++NumEntries;
     if (NumEntries*4 >= NumBuckets*3 ||
         NumBuckets-(NumEntries+NumTombstones) < NumBuckets/8) {
       this->grow(NumBuckets * 2);
       LookupBucketFor(Key, TheBucket);
     }
-    ++NumEntries;
 
     // If we are writing over a tombstone, remember this.
     if (!KeyInfoT::isEqual(TheBucket->first, getEmptyKey()))

Added: llvm/trunk/unittests/ADT/DenseSetTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ADT/DenseSetTest.cpp?rev=70572&view=auto

==============================================================================
--- llvm/trunk/unittests/ADT/DenseSetTest.cpp (added)
+++ llvm/trunk/unittests/ADT/DenseSetTest.cpp Fri May  1 15:47:53 2009
@@ -0,0 +1,30 @@
+//===- llvm/unittest/ADT/DenseSetTest.cpp - DenseSet unit tests --*- C++ -*-===//
+//
+//                     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/DenseSet.h>
+
+using namespace llvm;
+
+namespace {
+
+// Test fixture
+class DenseSetTest : public testing::Test {
+};
+
+// Test hashing with a set of only two entries.
+TEST_F(DenseSetTest, DoubleEntrySetTest) {
+  llvm::DenseSet<unsigned> set(2);
+  set.insert(0);
+  set.insert(1);
+  // Original failure was an infinite loop in this call:
+  EXPECT_EQ(0, set.count(2));
+}
+
+}