sim: A trie data structure specifically to speed up paging lookups.

This change adds a trie data structure which stores an arbitrary pointer type
based on an address and a number of relevant bits. Then lookups can be done
against the trie where the tree is traversed and the first legitimate match
found is returned.

2 files changed, 128 insertions, 0 deletions

diff --git a/src/unittest/SConscript b/src/unittest/SConscript
index 606bffd05..3ceae23b5 100644
--- a/src/unittest/SConscript
+++ b/src/unittest/SConscript
@@ -48,6 +48,7 @@ UnitTest('rangemaptest', 'rangemaptest.cc')
 UnitTest('rangemultimaptest', 'rangemultimaptest.cc')
 UnitTest('refcnttest', 'refcnttest.cc')
 UnitTest('strnumtest', 'strnumtest.cc')
+UnitTest('trietest', 'trietest.cc')
 
 stattest_py = PySource('m5', 'stattestmain.py', skip_lib=True)
 stattest_swig = SwigSource('m5.internal', 'stattest.i', skip_lib=True)
diff --git a/src/unittest/trietest.cc b/src/unittest/trietest.cc
new file mode 100644
index 000000000..ed8a772fa
--- /dev/null
+++ b/src/unittest/trietest.cc
@@ -0,0 +1,127 @@
+/*
+ * Copyright (c) 2012 Google
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Gabe Black
+ */
+
+#include <cassert>
+#include <iostream>
+
+#include "base/cprintf.hh"
+#include "base/trie.hh"
+#include "base/types.hh"
+#include "unittest/unittest.hh"
+
+using UnitTest::setCase;
+
+typedef Trie<Addr, uint32_t> TestTrie;
+
+int
+main()
+{
+    // Create an empty Ptr and verify it's data pointer is NULL.
+    setCase("An empty trie.");
+    TestTrie trie1;
+    trie1.dump("Empty");
+    cprintf("\n\n");
+
+    setCase("A single entry.");
+    trie1.insert(0x0123456789abcdef, 40, (uint32_t *)(uintptr_t)(1));
+    trie1.dump("One entry");
+    cprintf("\n\n");
+
+    setCase("Two entries, one on the way to the other.");
+    TestTrie trie2;
+    trie2.insert(0x0123456789abcdef, 40, (uint32_t *)(uintptr_t)(1));
+    trie2.insert(0x0123456789abcdef, 36, (uint32_t *)(uintptr_t)(2));
+    trie2.dump("Two entries inline v1");
+    cprintf("\n\n");
+
+    TestTrie trie3;
+    trie3.insert(0x0123456789abcdef, 36, (uint32_t *)(uintptr_t)(2));
+    trie3.insert(0x0123456789abcdef, 40, (uint32_t *)(uintptr_t)(1));
+    trie3.dump("Two entries inline v2");
+    cprintf("\n\n");
+
+    setCase("Two entries on different paths.");
+    TestTrie trie4;
+    trie4.insert(0x0123456789abcdef, 40, (uint32_t *)(uintptr_t)(2));
+    trie4.insert(0x0123456776543210, 40, (uint32_t *)(uintptr_t)(1));
+    trie4.dump("Two split entries");
+    cprintf("\n\n");
+
+    setCase("Skipping past an entry but not two.");
+    TestTrie trie5;
+    trie5.insert(0x0123456789000000, 40, (uint32_t *)(uintptr_t)(4));
+    trie5.insert(0x0123000000000000, 40, (uint32_t *)(uintptr_t)(1));
+    trie5.insert(0x0123456780000000, 40, (uint32_t *)(uintptr_t)(3));
+    trie5.insert(0x0123456700000000, 40, (uint32_t *)(uintptr_t)(2));
+    trie5.dump("Complex insertion");
+    cprintf("\n\n");
+
+    setCase("Looking things up.");
+    EXPECT_EQ((uintptr_t)trie5.lookup(0x0123000000000000), 1);
+    EXPECT_EQ((uintptr_t)trie5.lookup(0x0123456700000000), 2);
+    EXPECT_EQ((uintptr_t)trie5.lookup(0x0123456780000000), 3);
+    EXPECT_EQ((uintptr_t)trie5.lookup(0x0123456789000000), 4);
+
+    setCase("Removing entries.");
+    TestTrie trie6;
+    TestTrie::Handle node1, node2;
+    trie6.insert(0x0123456789000000, 40, (uint32_t *)(uintptr_t)(4));
+    trie6.insert(0x0123000000000000, 40, (uint32_t *)(uintptr_t)(1));
+    trie6.insert(0x0123456780000000, 40, (uint32_t *)(uintptr_t)(3));
+    node1 = trie6.insert(0x0123456700000000, 40, (uint32_t *)(uintptr_t)(2));
+    node2 = trie6.insert(0x0123456700000000, 32, (uint32_t *)(uintptr_t)(10));
+    trie6.dump("Fill before removal");
+    cprintf("\n\n");
+
+    EXPECT_EQ((uintptr_t)trie6.lookup(0x0123000000000000), 1);
+    EXPECT_EQ((uintptr_t)trie6.lookup(0x0123456700000000), 10);
+    EXPECT_EQ((uintptr_t)trie6.lookup(0x0123456780000000), 10);
+    EXPECT_EQ((uintptr_t)trie6.lookup(0x0123456789000000), 10);
+
+    trie6.remove(node2);
+    trie6.dump("One node removed");
+    cprintf("\n\n");
+
+    EXPECT_EQ((uintptr_t)trie6.lookup(0x0123000000000000), 1);
+    EXPECT_EQ((uintptr_t)trie6.lookup(0x0123456700000000), 2);
+    EXPECT_EQ((uintptr_t)trie6.lookup(0x0123456780000000), 3);
+    EXPECT_EQ((uintptr_t)trie6.lookup(0x0123456789000000), 4);
+
+    trie6.remove(node1);
+    trie6.dump("Two nodes removed");
+    cprintf("\n\n");
+
+    EXPECT_EQ((uintptr_t)trie6.lookup(0x0123000000000000), 1);
+    EXPECT_EQ(trie6.lookup(0x0123456700000000), NULL);
+    EXPECT_EQ((uintptr_t)trie6.lookup(0x0123456780000000), 3);
+    EXPECT_EQ((uintptr_t)trie6.lookup(0x0123456789000000), 4);
+
+    return UnitTest::printResults();
+}