Improve StringMap iterator support.

StringMap's iterators did not support LLVM's
iterator_facade_base, which made it unusable in various
STL algorithms or with some of our range adapters.
This patch makes both StringMapConstIterator as well as
StringMapIterator support iterator_facade_base.

With this in place, it is easy to make an iterator adapter
that iterates over only keys, and whose value_type is
StringRef.  So I add StringMapKeyIterator as well, and
provide the method StringMap::keys() that returns a
range that can be iterated.

Differential Revision: https://reviews.llvm.org/D31171

llvm-svn: 298436

1 files changed, 29 insertions, 0 deletions

diff --git a/llvm/unittests/ADT/StringMapTest.cpp b/llvm/unittests/ADT/StringMapTest.cpp
index 911c72d7496..d2b1c31805e 100644
--- a/llvm/unittests/ADT/StringMapTest.cpp
+++ b/llvm/unittests/ADT/StringMapTest.cpp
@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringSet.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/DataTypes.h"
 #include "gtest/gtest.h"
@@ -269,6 +270,34 @@ TEST_F(StringMapTest, InsertRehashingPairTest) {
   EXPECT_EQ(42u, It->second);
 }
 
+TEST_F(StringMapTest, IterMapKeys) {
+  StringMap<int> Map;
+  Map["A"] = 1;
+  Map["B"] = 2;
+  Map["C"] = 3;
+  Map["D"] = 3;
+
+  auto Keys = to_vector<4>(Map.keys());
+  std::sort(Keys.begin(), Keys.end());
+
+  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());
+  std::sort(Keys.begin(), Keys.end());
+
+  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) {}