Add ADL support to range based <algorithm> extensions

This adds support for ADL in the range based <algorithm> extensions
(llvm::for_each etc.).

Also adds the helper functions llvm::adl::begin and llvm::adl::end which wrap
std::begin and std::end with ADL support.

Saw this was missing from a recent llvm weekly post about adding llvm::for_each
and thought I might add it.

Patch by Stephen Dollberg!

Differential Revision: https://reviews.llvm.org/D40006

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318703 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 52 insertions, 14 deletions

diff --git a/unittests/ADT/STLExtrasTest.cpp b/unittests/ADT/STLExtrasTest.cpp
index 68cd9f5d2c8..89e876eb4de 100644
--- a/unittests/ADT/STLExtrasTest.cpp
+++ b/unittests/ADT/STLExtrasTest.cpp
@@ -252,20 +252,20 @@ TEST(STLExtrasTest, CountAdaptor) {
   EXPECT_EQ(3, count(v, 1));
   EXPECT_EQ(2, count(v, 2));
   EXPECT_EQ(1, count(v, 3));
-  EXPECT_EQ(1, count(v, 4));

-}

-

-TEST(STLExtrasTest, for_each) {

-  std::vector<int> v{ 0, 1, 2, 3, 4 };

-  int count = 0;

-

-  llvm::for_each(v, [&count](int) { ++count; });

-  EXPECT_EQ(5, count);

-}

-

-TEST(STLExtrasTest, ToVector) {

-  std::vector<char> v = {'a', 'b', 'c'};

-  auto Enumerated = to_vector<4>(enumerate(v));

+  EXPECT_EQ(1, count(v, 4));
+}
+
+TEST(STLExtrasTest, for_each) {
+  std::vector<int> v{0, 1, 2, 3, 4};
+  int count = 0;
+
+  llvm::for_each(v, [&count](int) { ++count; });
+  EXPECT_EQ(5, count);
+}
+
+TEST(STLExtrasTest, ToVector) {
+  std::vector<char> v = {'a', 'b', 'c'};
+  auto Enumerated = to_vector<4>(enumerate(v));
   ASSERT_EQ(3u, Enumerated.size());
   for (size_t I = 0; I < v.size(); ++I) {
     EXPECT_EQ(I, Enumerated[I].index());
@@ -326,4 +326,42 @@ TEST(STLExtrasTest, EraseIf) {
   EXPECT_EQ(7, V[3]);
 }
 
+namespace some_namespace {
+struct some_struct {
+  std::vector<int> data;
+  std::string swap_val;
+};
+
+std::vector<int>::const_iterator begin(const some_struct &s) {
+  return s.data.begin();
+}
+
+std::vector<int>::const_iterator end(const some_struct &s) {
+  return s.data.end();
 }
+
+void swap(some_struct &lhs, some_struct &rhs) {
+  // make swap visible as non-adl swap would even seem to
+  // work with std::swap which defaults to moving
+  lhs.swap_val = "lhs";
+  rhs.swap_val = "rhs";
+}
+} // namespace some_namespace
+
+TEST(STLExtrasTest, ADLTest) {
+  some_namespace::some_struct s{{1, 2, 3, 4, 5}, ""};
+  some_namespace::some_struct s2{{2, 4, 6, 8, 10}, ""};
+
+  EXPECT_EQ(*adl_begin(s), 1);
+  EXPECT_EQ(*(adl_end(s) - 1), 5);
+
+  adl_swap(s, s2);
+  EXPECT_EQ(s.swap_val, "lhs");
+  EXPECT_EQ(s2.swap_val, "rhs");
+
+  int count = 0;
+  llvm::for_each(s, [&count](int) { ++count; });
+  EXPECT_EQ(5, count);
+}
+
+} // namespace