[ADT] Enable set_difference() to be used on StringSet

[mmpozulp]

I meant to run arc diff --update D62369 but I ran arc diff instead, oops! Please ignore this revision.

[mmpozulp]

Please see https://reviews.llvm.org/D62369 which is the revision that I meant to update. Instead I created this new revision by accident.

llvm/include/llvm/ADT/StringMap.h

public:
   /// if the key is not in the map.
   ValueTy &operator[](StringRef Key) { return try_emplace(Key).first->second; }
 
   /// count - Return 1 if the element is in the map, 0 otherwise.
   size_type count(StringRef Key) const {
     return find(Key) == end() ? 0 : 1;
   }
 
+  template <typename InputTy>
+  size_type count(const StringMapEntry<InputTy> &MapEntry) const {
+    return count(MapEntry.getKey());
+  }
+
   /// insert - Insert the specified key/value pair into the map.  If the key
   /// already exists in the map, return false and ignore the request, otherwise
   /// insert it and return true.
   bool insert(MapEntryTy *KeyValue) {
     unsigned BucketNo = LookupBucketFor(KeyValue->getKey());
     StringMapEntryBase *&Bucket = TheTable[BucketNo];
     if (Bucket && Bucket != getTombstoneVal())
       return false;  // Already exists in map.

llvm/include/llvm/ADT/StringSet.h

std::pair<typename base::iterator, bool> insert(StringRef Key) {
       return base::insert(std::make_pair(Key, '\0'));
     }
 
     template <typename InputIt>
     void insert(const InputIt &Begin, const InputIt &End) {
       for (auto It = Begin; It != End; ++It)
         base::insert(std::make_pair(*It, '\0'));
     }
+
+    template <typename ValueTy>
+    std::pair<typename base::iterator, bool>
+    insert(const StringMapEntry<ValueTy> &MapEntry) {
+      return insert(MapEntry.getKey());
+    }
   };
 
 } // end namespace llvm
 
 #endif // LLVM_ADT_STRINGSET_H

llvm/unittests/ADT/CMakeLists.txt

add_llvm_unittest(ADTTests
   SmallVectorTest.cpp
   SparseBitVectorTest.cpp
   SparseMultiSetTest.cpp
   SparseSetTest.cpp
   StatisticTest.cpp
   StringExtrasTest.cpp
   StringMapTest.cpp
   StringRefTest.cpp
+  StringSetTest.cpp
   StringSwitchTest.cpp
   TinyPtrVectorTest.cpp
   TripleTest.cpp
   TwineTest.cpp
   VariadicFunctionTest.cpp
   )
 
 target_link_libraries(ADTTests PRIVATE LLVMTestingSupport)
 
 add_dependencies(ADTTests intrinsics_gen)

llvm/unittests/ADT/StringMapTest.cpp

 //===- llvm/unittest/ADT/StringMapMap.cpp - StringMap unit tests ----------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/StringMap.h"
-#include "llvm/ADT/StringSet.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/DataTypes.h"
 #include "gtest/gtest.h"
 #include <limits>
 #include <tuple>
 using namespace llvm;
 
 namespace {
TEST_F(StringMapTest, IterMapKeys) {
 
   auto Keys = to_vector<4>(Map.keys());
   llvm::sort(Keys);
 
   SmallVector<StringRef, 4> Expected = {"A", "B", "C", "D"};
   EXPECT_EQ(Expected, Keys);
 }
 
-TEST_F(StringMapTest, IterSetKeys) {
-  StringSet<> Set;
-  Set.insert("A");
-  Set.insert("B");
-  Set.insert("C");
-  Set.insert("D");
-
-  auto Keys = to_vector<4>(Set.keys());
-  llvm::sort(Keys);
-
-  SmallVector<StringRef, 4> Expected = {"A", "B", "C", "D"};
-  EXPECT_EQ(Expected, Keys);
-}
-
 // Create a non-default constructable value
 struct StringMapTestStruct {
   StringMapTestStruct(int i) : i(i) {}
   StringMapTestStruct() = delete;
   int i;
 };
 
 TEST_F(StringMapTest, NonDefaultConstructable) {

llvm/unittests/ADT/StringSetTest.cpp

+//===- llvm/unittest/ADT/StringSetTest.cpp - StringSet unit tests ----------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/StringSet.h"
+#include "gtest/gtest.h"
+using namespace llvm;
+
+namespace {
+
+// Test fixture
+class StringSetTest : public testing::Test {};
+
+TEST_F(StringSetTest, IterSetKeys) {
+  StringSet<> Set;
+  Set.insert("A");
+  Set.insert("B");
+  Set.insert("C");
+  Set.insert("D");
+
+  auto Keys = to_vector<4>(Set.keys());
+  llvm::sort(Keys);
+
+  SmallVector<StringRef, 4> Expected = {"A", "B", "C", "D"};
+  EXPECT_EQ(Expected, Keys);
+}
+
+TEST_F(StringSetTest, InsertAndCountStringMapEntry) {
+  // Test insert(StringMapEntry) and count(StringMapEntry)
+  // which are required for set_difference(StringSet, StringSet).
+  StringSet<> Set;
+  StringMapEntry<StringRef> Element(1, "A");
+  Set.insert(Element);
+  size_t Count = Set.count(Element);
+  size_t Expected = 1;
+  EXPECT_EQ(Expected, Count);
+}
+
+} // end anonymous namespace