[compiler-rt] 9e5f3dd - [ORC-RT] Add apply_tuple utility.

[Lang Hames via llvm-commits]

Author: Lang Hames
Date: 2021-05-18T08:44:15-07:00
New Revision: 9e5f3dd9dbb0c4eb0d2d341329a780b828f70fb0

URL: https://github.com/llvm/llvm-project/commit/9e5f3dd9dbb0c4eb0d2d341329a780b828f70fb0
DIFF: https://github.com/llvm/llvm-project/commit/9e5f3dd9dbb0c4eb0d2d341329a780b828f70fb0.diff

LOG: [ORC-RT] Add apply_tuple utility.

This is a substitute for std::apply, which we can't use until we move to c++17.

apply_tuple will be used in upcoming the upcoming wrapper-function utils code.

Added: 
    compiler-rt/lib/orc/stl_extras.h
    compiler-rt/lib/orc/unittests/stl_extras_test.cpp

Modified: 
    compiler-rt/lib/orc/unittests/CMakeLists.txt

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/orc/stl_extras.h b/compiler-rt/lib/orc/stl_extras.h
new file mode 100644
index 0000000000000..5af9de4a9dbbf
--- /dev/null
+++ b/compiler-rt/lib/orc/stl_extras.h
@@ -0,0 +1,45 @@
+//===-------- stl_extras.h - Useful STL related functions-------*- 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of the ORC runtime support library.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef ORC_RT_STL_EXTRAS_H
+#define ORC_RT_STL_EXTRAS_H
+
+#include <utility>
+
+namespace __orc_rt {
+
+namespace detail {
+
+template <typename F, typename Tuple, std::size_t... I>
+decltype(auto) apply_tuple_impl(F &&f, Tuple &&t, std::index_sequence<I...>) {
+  return std::forward<F>(f)(std::get<I>(std::forward<Tuple>(t))...);
+}
+
+} // end namespace detail
+
+/// Given an input tuple (a1, a2, ..., an), pass the arguments of the
+/// tuple variadically to f as if by calling f(a1, a2, ..., an) and
+/// return the result.
+///
+/// FIXME: Switch to std::apply once we can use c++17.
+template <typename F, typename Tuple>
+decltype(auto) apply_tuple(F &&f, Tuple &&t) {
+  using Indices = std::make_index_sequence<
+      std::tuple_size<typename std::decay<Tuple>::type>::value>;
+
+  return detail::apply_tuple_impl(std::forward<F>(f), std::forward<Tuple>(t),
+                                  Indices{});
+}
+
+} // namespace __orc_rt
+
+#endif // ORC_RT_STL_EXTRAS

diff  --git a/compiler-rt/lib/orc/unittests/CMakeLists.txt b/compiler-rt/lib/orc/unittests/CMakeLists.txt
index b9884b49e7429..1783a4a092ed7 100644
--- a/compiler-rt/lib/orc/unittests/CMakeLists.txt
+++ b/compiler-rt/lib/orc/unittests/CMakeLists.txt
@@ -82,6 +82,7 @@ endmacro()
 set(UNITTEST_SOURCES
   extensible_rtti_test.cpp
   orc_unit_test_main.cpp
+  stl_extras_test.cpp
   )
 
 if (COMPILER_RT_CAN_EXECUTE_TESTS)

diff  --git a/compiler-rt/lib/orc/unittests/stl_extras_test.cpp b/compiler-rt/lib/orc/unittests/stl_extras_test.cpp
new file mode 100644
index 0000000000000..0a505c00dc01c
--- /dev/null
+++ b/compiler-rt/lib/orc/unittests/stl_extras_test.cpp
@@ -0,0 +1,65 @@
+//===-- stl_extras_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.
+//
+// Note:
+//   This unit test was adapted from tests in
+//   llvm/unittests/ADT/STLExtrasTest.cpp
+//
+//===----------------------------------------------------------------------===//
+
+#include "stl_extras.h"
+#include "gtest/gtest.h"
+
+using namespace __orc_rt;
+
+TEST(STLExtrasTest, ApplyTuple) {
+  auto T = std::make_tuple(1, 3, 7);
+  auto U = __orc_rt::apply_tuple(
+      [](int A, int B, int C) { return std::make_tuple(A - B, B - C, C - A); },
+      T);
+
+  EXPECT_EQ(-2, std::get<0>(U));
+  EXPECT_EQ(-4, std::get<1>(U));
+  EXPECT_EQ(6, std::get<2>(U));
+
+  auto V = __orc_rt::apply_tuple(
+      [](int A, int B, int C) {
+        return std::make_tuple(std::make_pair(A, char('A' + A)),
+                               std::make_pair(B, char('A' + B)),
+                               std::make_pair(C, char('A' + C)));
+      },
+      T);
+
+  EXPECT_EQ(std::make_pair(1, 'B'), std::get<0>(V));
+  EXPECT_EQ(std::make_pair(3, 'D'), std::get<1>(V));
+  EXPECT_EQ(std::make_pair(7, 'H'), std::get<2>(V));
+}
+
+class apply_variadic {
+  static int apply_one(int X) { return X + 1; }
+  static char apply_one(char C) { return C + 1; }
+  static std::string apply_one(std::string S) {
+    return S.substr(0, S.size() - 1);
+  }
+
+public:
+  template <typename... Ts> auto operator()(Ts &&... Items) {
+    return std::make_tuple(apply_one(Items)...);
+  }
+};
+
+TEST(STLExtrasTest, ApplyTupleVariadic) {
+  auto Items = std::make_tuple(1, std::string("Test"), 'X');
+  auto Values = __orc_rt::apply_tuple(apply_variadic(), Items);
+
+  EXPECT_EQ(2, std::get<0>(Values));
+  EXPECT_EQ("Tes", std::get<1>(Values));
+  EXPECT_EQ('Y', std::get<2>(Values));
+}