[ORC-RT] Add IntervalMap and IntervalSet collections.

IntervalMap is an optionally-coalescing map -- it uses half-open ranges as keys,
allows lookups based on elements of the ranges (returning an iterator to the
containing range) and optionally coalesces adjacent ranges that have the same
value.

IntervalSet is an optionally-coalescing set based on IntervalMap.

These collections will be used to store and lookup metadata section ranges,
e.g. unwind-info ranges.

compiler-rt/lib/orc/interval_map.h

@@ -0,0 +1,153 @@
+//===--------- interval_map.h - A sorted interval map -----------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Implements a coalescing interval map.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef ORC_RT_INTERVAL_MAP_H
+#define ORC_RT_INTERVAL_MAP_H
+
+#include "adt.h"
+#include <cassert>
+#include <map>
+
+namespace __orc_rt {
+
+enum class IntervalCoalescing { Enabled, Disabled };
+
+/// Maps intervals to keys with optional coalescing.
+///
+/// NOTE: The interface is kept mostly compatible with LLVM's IntervalMap
+///       collection to make it easy to swap over in the future if we choose
+///       to.
+template <typename KeyT, typename ValT, IntervalCoalescing Coalescing>
+class IntervalMap {
+private:
+  using KeyPairT = std::pair<KeyT, KeyT>;
+
+  struct Compare {
+    using is_transparent = std::true_type;
+    bool operator()(const KeyPairT &LHS, const KeyPairT &RHS) const {
+      return LHS < RHS;
+    }
+    bool operator()(const KeyPairT &LHS, const KeyT &RHS) const {
+      return LHS.first < RHS;
+    }
+    bool operator()(const KeyT &LHS, const KeyPairT &RHS) const {
+      return LHS < RHS.first;
+    }
+  };
+
+  using ImplMap = std::map<KeyPairT, ValT, Compare>;
+
+public:
+  using iterator = typename ImplMap::iterator;
+  using const_iterator = typename ImplMap::const_iterator;
+  using size_type = typename ImplMap::size_type;
+
+  bool empty() const { return Impl.empty(); }
+
+  void clear() { Impl.clear(); }
+
+  iterator begin() { return Impl.begin(); }
+  iterator end() { return Impl.end(); }
+
+  const_iterator begin() const { return Impl.begin(); }
+  const_iterator end() const { return Impl.end(); }
+
+  iterator find(KeyT K) {
+    // Early out if the key is clearly outside the range.
+    if (empty() || K < begin()->first.first ||
+        K >= std::prev(end())->first.second)
+      return end();
+
+    auto I = Impl.upper_bound(K);
+    assert(I != begin() && "Should have hit early out above");
+    I = std::prev(I);
+    if (K < I->first.second)
+      return I;
+    return end();
+  }
+
+  const_iterator find(KeyT K) const {
+    return const_cast<IntervalMap<KeyT, ValT, Coalescing> *>(this)->find(K);
+  }
+
+  ValT lookup(KeyT K, ValT NotFound = ValT()) const {
+    auto I = find(K);
+    if (I == end())
+      return NotFound;
+    return I->second;
+  }
+
+  void insert(KeyT KS, KeyT KE, ValT V) {
+    if (Coalescing == IntervalCoalescing::Enabled) {
+      auto J = Impl.upper_bound(KS);
+
+      // Coalesce-right if possible. Either way, J points at our insertion
+      // point.
+      if (J != end() && KE == J->first.first && J->second == V) {
+        KE = J->first.second;
+        auto Tmp = J++;
+        Impl.erase(Tmp);
+      }
+
+      // Coalesce-left if possible.
+      if (J != begin()) {
+        auto I = std::prev(J);
+        if (I->first.second == KS && I->second == V) {
+          KS = I->first.first;
+          Impl.erase(I);
+        }
+      }
+      Impl.insert(J, std::make_pair(std::make_pair(KS, KE), std::move(V)));
+    } else
+      Impl.insert(std::make_pair(std::make_pair(KS, KE), std::move(V)));
+  }
+
+  // Erase [KS, KE), which must be entirely containing within one existing
+  // range in the map. Removal is allowed to split the range.
+  void erase(KeyT KS, KeyT KE) {
+    if (empty())
+      return;
+
+    auto J = Impl.upper_bound(KS);
+
+    // Check previous range. Bail out if range to remove is entirely after
+    // it.
+    auto I = std::prev(J);
+    if (KS >= I->first.second)
+      return;
+
+    // Assert that range is wholly contained.
+    assert(KE <= I->first.second);
+
+    auto Tmp = std::move(*I);
+    Impl.erase(I);
+
+    // Split-right -- introduce right-split range.
+    if (KE < Tmp.first.second) {
+      Impl.insert(
+          J, std::make_pair(std::make_pair(KE, Tmp.first.second), Tmp.second));
+      J = std::prev(J);
+    }
+
+    // Split-left -- introduce left-split range.
+    if (KS > Tmp.first.first)
+      Impl.insert(
+          J, std::make_pair(std::make_pair(Tmp.first.first, KS), Tmp.second));
+  }
+
+private:
+  ImplMap Impl;
+};
+
+} // End namespace __orc_rt
+
+#endif // ORC_RT_INTERVAL_MAP_H

compiler-rt/lib/orc/macho_platform.cpp

@@ -14,6 +14,7 @@
 #include "common.h"
 #include "debug.h"
 #include "error.h"
+#include "interval_map.h"
 #include "wrapper_function_utils.h"
 
 #include <algorithm>

compiler-rt/lib/orc/tests/unit/CMakeLists.txt

@@ -5,6 +5,8 @@ set(UNITTEST_SOURCES
   error_test.cpp
   executor_address_test.cpp
   extensible_rtti_test.cpp
+  interval_map_test.cpp
+  interval_set_test.cpp
   orc_unit_test_main.cpp
   wrapper_function_utils_test.cpp
   simple_packed_serialization_test.cpp

compiler-rt/lib/orc/tests/unit/interval_map_test.cpp

@@ -0,0 +1,188 @@
+//===-- interval_map_test.cpp ---------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of the ORC runtime.
+//
+//===----------------------------------------------------------------------===//
+
+#include "interval_map.h"
+#include "gtest/gtest.h"
+
+using namespace __orc_rt;
+
+TEST(IntervalMapTest, DefaultConstructed) {
+  // Check that a default-constructed IntervalMap behaves as expected.
+  IntervalMap<unsigned, unsigned, IntervalCoalescing::Enabled> M;
+
+  EXPECT_TRUE(M.empty());
+  EXPECT_TRUE(M.begin() == M.end());
+  EXPECT_TRUE(M.find(0) == M.end());
+}
+
+TEST(IntervalMapTest, InsertSingleElement) {
+  // Check that a map with a single element inserted behaves as expected.
+  IntervalMap<unsigned, unsigned, IntervalCoalescing::Enabled> M;
+
+  M.insert(7, 8, 42);
+
+  EXPECT_FALSE(M.empty());
+  EXPECT_EQ(std::next(M.begin()), M.end());
+  EXPECT_EQ(M.find(7), M.begin());
+  EXPECT_EQ(M.find(8), M.end());
+  EXPECT_EQ(M.lookup(7), 42U);
+  EXPECT_EQ(M.lookup(8), 0U); // 8 not present, so should return unsigned().
+}
+
+TEST(IntervalMapTest, InsertCoalesceWithPrevious) {
+  // Check that insertions coalesce with previous ranges that share the same
+  // value. Also check that they _don't_ coalesce if the values are different.
+
+  // Check that insertion coalesces with previous range when values are equal.
+  IntervalMap<unsigned, unsigned, IntervalCoalescing::Enabled> M1;
+
+  M1.insert(7, 8, 42);
+  M1.insert(8, 9, 42);
+
+  EXPECT_FALSE(M1.empty());
+  EXPECT_EQ(std::next(M1.begin()), M1.end()); // Should see just one range.
+  EXPECT_EQ(M1.find(7), M1.find(8)); // 7 and 8 should point to same range.
+  EXPECT_EQ(M1.lookup(7), 42U);      // Value should be preserved.
+
+  // Check that insertion does not coalesce with previous range when values are
+  // not equal.
+  IntervalMap<unsigned, unsigned, IntervalCoalescing::Enabled> M2;
+
+  M2.insert(7, 8, 42);
+  M2.insert(8, 9, 7);
+
+  EXPECT_FALSE(M2.empty());
+  EXPECT_EQ(std::next(std::next(M2.begin())), M2.end()); // Expect two ranges.
+  EXPECT_NE(M2.find(7), M2.find(8)); // 7 and 8 should be different ranges.
+  EXPECT_EQ(M2.lookup(7), 42U); // Keys 7 and 8 should map to different values.
+  EXPECT_EQ(M2.lookup(8), 7U);
+}
+
+TEST(IntervalMapTest, InsertCoalesceWithFollowing) {
+  // Check that insertions coalesce with following ranges that share the same
+  // value. Also check that they _don't_ coalesce if the values are different.
+
+  // Check that insertion coalesces with following range when values are equal.
+  IntervalMap<unsigned, unsigned, IntervalCoalescing::Enabled> M1;
+
+  M1.insert(8, 9, 42);
+  M1.insert(7, 8, 42);
+
+  EXPECT_FALSE(M1.empty());
+  EXPECT_EQ(std::next(M1.begin()), M1.end()); // Should see just one range.
+  EXPECT_EQ(M1.find(7), M1.find(8)); // 7 and 8 should point to same range.
+  EXPECT_EQ(M1.lookup(7), 42U);      // Value should be preserved.
+
+  // Check that insertion does not coalesce with previous range when values are
+  // not equal.
+  IntervalMap<unsigned, unsigned, IntervalCoalescing::Enabled> M2;
+
+  M2.insert(8, 9, 42);
+  M2.insert(7, 8, 7);
+
+  EXPECT_FALSE(M2.empty());
+  EXPECT_EQ(std::next(std::next(M2.begin())), M2.end()); // Expect two ranges.
+  EXPECT_EQ(M2.lookup(7), 7U); // Keys 7 and 8 should map to different values.
+  EXPECT_EQ(M2.lookup(8), 42U);
+}
+
+TEST(IntervalMapTest, InsertCoalesceBoth) {
+  // Check that insertions coalesce with ranges on both sides where posssible.
+  // Also check that they _don't_ coalesce if the values are different.
+
+  // Check that insertion coalesces with both previous and following ranges
+  // when values are equal.
+  IntervalMap<unsigned, unsigned, IntervalCoalescing::Enabled> M1;
+
+  M1.insert(7, 8, 42);
+  M1.insert(9, 10, 42);
+
+  // Check no coalescing yet.
+  EXPECT_NE(M1.find(7), M1.find(9));
+
+  // Insert a 3rd range to trigger coalescing on both sides.
+  M1.insert(8, 9, 42);
+
+  EXPECT_FALSE(M1.empty());
+  EXPECT_EQ(std::next(M1.begin()), M1.end()); // Should see just one range.
+  EXPECT_EQ(M1.find(7), M1.find(8)); // 7, 8, and 9 should point to same range.
+  EXPECT_EQ(M1.find(8), M1.find(9));
+  EXPECT_EQ(M1.lookup(7), 42U); // Value should be preserved.
+
+  // Check that insertion does not coalesce with previous range when values are
+  // not equal.
+  IntervalMap<unsigned, unsigned, IntervalCoalescing::Enabled> M2;
+
+  M2.insert(7, 8, 42);
+  M2.insert(8, 9, 7);
+  M2.insert(9, 10, 42);
+
+  EXPECT_FALSE(M2.empty());
+  // Expect three ranges.
+  EXPECT_EQ(std::next(std::next(std::next(M2.begin()))), M2.end());
+  EXPECT_NE(M2.find(7), M2.find(8)); // All keys should map to different ranges.
+  EXPECT_NE(M2.find(8), M2.find(9));
+  EXPECT_EQ(M2.lookup(7), 42U); // Key 7, 8, and 9 should map to different vals.
+  EXPECT_EQ(M2.lookup(8), 7U);
+  EXPECT_EQ(M2.lookup(9), 42U);
+}
+
+TEST(IntervalMapTest, EraseSingleElement) {
+  // Check that we can insert and then remove a single range.
+  IntervalMap<unsigned, unsigned, IntervalCoalescing::Enabled> M;
+
+  M.insert(7, 10, 42);
+  EXPECT_FALSE(M.empty());
+  M.erase(7, 10);
+  EXPECT_TRUE(M.empty());
+}
+
+TEST(IntervalMapTest, EraseSplittingLeft) {
+  // Check that removal of a trailing subrange succeeds, but leaves the
+  // residual range in-place.
+  IntervalMap<unsigned, unsigned, IntervalCoalescing::Enabled> M;
+
+  M.insert(7, 10, 42);
+  EXPECT_FALSE(M.empty());
+  M.erase(9, 10);
+  EXPECT_EQ(std::next(M.begin()), M.end());
+  EXPECT_EQ(M.begin()->first.first, 7U);
+  EXPECT_EQ(M.begin()->first.second, 9U);
+}
+
+TEST(IntervalMapTest, EraseSplittingRight) {
+  // Check that removal of a leading subrange succeeds, but leaves the
+  // residual range in-place.
+  IntervalMap<unsigned, unsigned, IntervalCoalescing::Enabled> M;
+
+  M.insert(7, 10, 42);
+  EXPECT_FALSE(M.empty());
+  M.erase(7, 8);
+  EXPECT_EQ(std::next(M.begin()), M.end());
+  EXPECT_EQ(M.begin()->first.first, 8U);
+  EXPECT_EQ(M.begin()->first.second, 10U);
+}
+
+TEST(IntervalMapTest, EraseSplittingBoth) {
+  // Check that removal of an interior subrange leaves both the leading and
+  // trailing residual subranges in-place.
+  IntervalMap<unsigned, unsigned, IntervalCoalescing::Enabled> M;
+
+  M.insert(7, 10, 42);
+  EXPECT_FALSE(M.empty());
+  M.erase(8, 9);
+  EXPECT_EQ(std::next(std::next(M.begin())), M.end());
+  EXPECT_EQ(M.begin()->first.first, 7U);
+  EXPECT_EQ(M.begin()->first.second, 8U);
+  EXPECT_EQ(std::next(M.begin())->first.first, 9U);
+  EXPECT_EQ(std::next(M.begin())->first.second, 10U);
+}