[llvm] [libc] Add invoke / invoke_result type traits (PR #65750)
Guillaume Chatelet via llvm-commits
llvm-commits at lists.llvm.org
Wed Sep 13 05:23:33 PDT 2023
https://github.com/gchatelet updated https://github.com/llvm/llvm-project/pull/65750:
>From 6b7212b9d668de3202f9938e8016dd336aede1be Mon Sep 17 00:00:00 2001
From: Guillaume Chatelet <gchatelet at google.com>
Date: Fri, 8 Sep 2023 13:10:05 +0000
Subject: [PATCH] [libc] add invoke / invoke_result type traits
---
libc/src/__support/CPP/CMakeLists.txt | 2 +
libc/src/__support/CPP/type_traits.h | 2 +
libc/src/__support/CPP/type_traits/invoke.h | 58 +++++++++++++
.../__support/CPP/type_traits/invoke_result.h | 26 ++++++
.../src/__support/CPP/type_traits_test.cpp | 86 +++++++++++++++++++
.../llvm-project-overlay/libc/BUILD.bazel | 3 +
6 files changed, 177 insertions(+)
create mode 100644 libc/src/__support/CPP/type_traits/invoke.h
create mode 100644 libc/src/__support/CPP/type_traits/invoke_result.h
diff --git a/libc/src/__support/CPP/CMakeLists.txt b/libc/src/__support/CPP/CMakeLists.txt
index d24c023ec28ebc9..bb330a7b0ac5106 100644
--- a/libc/src/__support/CPP/CMakeLists.txt
+++ b/libc/src/__support/CPP/CMakeLists.txt
@@ -104,6 +104,8 @@ add_header_library(
type_traits/enable_if.h
type_traits/false_type.h
type_traits/integral_constant.h
+ type_traits/invoke.h
+ type_traits/invoke_result.h
type_traits/is_arithmetic.h
type_traits/is_array.h
type_traits/is_base_of.h
diff --git a/libc/src/__support/CPP/type_traits.h b/libc/src/__support/CPP/type_traits.h
index 9deb08b221593e1..3de2ca58903184c 100644
--- a/libc/src/__support/CPP/type_traits.h
+++ b/libc/src/__support/CPP/type_traits.h
@@ -18,6 +18,8 @@
#include "src/__support/CPP/type_traits/enable_if.h"
#include "src/__support/CPP/type_traits/false_type.h"
#include "src/__support/CPP/type_traits/integral_constant.h"
+#include "src/__support/CPP/type_traits/invoke.h"
+#include "src/__support/CPP/type_traits/invoke_result.h"
#include "src/__support/CPP/type_traits/is_arithmetic.h"
#include "src/__support/CPP/type_traits/is_array.h"
#include "src/__support/CPP/type_traits/is_base_of.h"
diff --git a/libc/src/__support/CPP/type_traits/invoke.h b/libc/src/__support/CPP/type_traits/invoke.h
new file mode 100644
index 000000000000000..e1f661339f349e7
--- /dev/null
+++ b/libc/src/__support/CPP/type_traits/invoke.h
@@ -0,0 +1,58 @@
+//===-- invoke type_traits --------------------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_SUPPORT_CPP_TYPE_TRAITS_INVOKE_H
+#define LLVM_LIBC_SRC_SUPPORT_CPP_TYPE_TRAITS_INVOKE_H
+
+#include "src/__support/CPP/type_traits/decay.h"
+#include "src/__support/CPP/type_traits/is_base_of.h"
+#include "src/__support/CPP/utility/forward.h"
+
+// BEWARE : this implementation is not fully conformant as it doesn't take
+// `cpp::reference_wrapper` into account.
+
+namespace __llvm_libc::cpp {
+
+namespace detail {
+
+// Catch all function types.
+template <class FunctionPtrType> struct invoke_dispatcher {
+ template <class... Args>
+ static auto call(FunctionPtrType &&fun, Args &&...args) {
+ return cpp::forward<FunctionPtrType>(fun)(cpp::forward<Args>(args)...);
+ }
+};
+
+// Catch pointer to member function types.
+template <class Class, class FunctionReturnType>
+struct invoke_dispatcher<FunctionReturnType Class::*> {
+ using FunctionPtrType = FunctionReturnType Class::*;
+
+ template <class T, class... Args, class DecayT = cpp::decay_t<T>>
+ static auto call(FunctionPtrType fun, T &&t1, Args &&...args) {
+ if constexpr (cpp::is_base_of_v<Class, DecayT>) {
+ // T is a (possibly cv ref) type.
+ return (cpp::forward<T>(t1).*fun)(cpp::forward<Args>(args)...);
+ } else {
+ // T is assumed to be a pointer type.
+ return (*cpp::forward<T>(t1).*fun)(cpp::forward<Args>(args)...);
+ }
+ }
+};
+
+} // namespace detail
+
+template <class Function, class... Args>
+auto invoke(Function &&fun, Args &&...args) {
+ return detail::invoke_dispatcher<cpp::decay_t<Function>>::call(
+ cpp::forward<Function>(fun), cpp::forward<Args>(args)...);
+}
+
+} // namespace __llvm_libc::cpp
+
+#endif // LLVM_LIBC_SRC_SUPPORT_CPP_TYPE_TRAITS_INVOKE_H
diff --git a/libc/src/__support/CPP/type_traits/invoke_result.h b/libc/src/__support/CPP/type_traits/invoke_result.h
new file mode 100644
index 000000000000000..1a071f5cb94836f
--- /dev/null
+++ b/libc/src/__support/CPP/type_traits/invoke_result.h
@@ -0,0 +1,26 @@
+//===-- invoke_result type_traits -------------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_LIBC_SRC_SUPPORT_CPP_TYPE_TRAITS_INVOKE_RESULT_H
+#define LLVM_LIBC_SRC_SUPPORT_CPP_TYPE_TRAITS_INVOKE_RESULT_H
+
+#include "src/__support/CPP/type_traits/invoke.h"
+#include "src/__support/CPP/utility/declval.h"
+
+namespace __llvm_libc::cpp {
+
+template <class F, class... Args> struct invoke_result {
+ using type =
+ decltype(cpp::invoke(cpp::declval<F>(), cpp::declval<Args>()...));
+};
+
+template <class F, class... Args>
+using invoke_result_t = typename invoke_result<F, Args...>::type;
+
+} // namespace __llvm_libc::cpp
+
+#endif // LLVM_LIBC_SRC_SUPPORT_CPP_TYPE_TRAITS_INVOKE_RESULT_H
diff --git a/libc/test/src/__support/CPP/type_traits_test.cpp b/libc/test/src/__support/CPP/type_traits_test.cpp
index cd025f588388d68..3c1a25b5a1033e9 100644
--- a/libc/test/src/__support/CPP/type_traits_test.cpp
+++ b/libc/test/src/__support/CPP/type_traits_test.cpp
@@ -145,6 +145,92 @@ TEST(LlvmLibcTypeTraitsTest, integral_constant) {
EXPECT_EQ((integral_constant<int, 4>::value), 4);
}
+namespace invoke_detail {
+
+enum State { INIT = 0, A_APPLY_CALLED, B_APPLY_CALLED };
+
+struct A {
+ State state = INIT;
+ virtual ~A() {}
+ virtual void apply() { state = A_APPLY_CALLED; }
+};
+
+struct B : public A {
+ virtual ~B() {}
+ virtual void apply() { state = B_APPLY_CALLED; }
+};
+
+void free_function() {}
+int free_function_return_5() { return 5; }
+int free_function_passtrough(int value) { return value; }
+
+struct Delegate {
+ int (*ptr)(int) = &free_function_passtrough;
+};
+
+} // namespace invoke_detail
+
+TEST(LlvmLibcTypeTraitsTest, invoke) {
+ using namespace invoke_detail;
+ { // member function call
+ A a;
+ EXPECT_EQ(a.state, INIT);
+ cpp::invoke(&A::apply, a);
+ EXPECT_EQ(a.state, A_APPLY_CALLED);
+ }
+ { // overriden member function call
+ B b;
+ EXPECT_EQ(b.state, INIT);
+ cpp::invoke(&A::apply, b);
+ EXPECT_EQ(b.state, B_APPLY_CALLED);
+ }
+ { // free function
+ cpp::invoke(&free_function);
+ EXPECT_EQ(cpp::invoke(&free_function_return_5), 5);
+ EXPECT_EQ(cpp::invoke(&free_function_passtrough, 1), 1);
+ }
+ { // pointer member function call
+ Delegate d;
+ EXPECT_EQ(cpp::invoke(&Delegate::ptr, d, 2), 2);
+ }
+ { // lambda
+ EXPECT_EQ(cpp::invoke([]() -> int { return 2; }), 2);
+ EXPECT_EQ(cpp::invoke([](int value) -> int { return value; }, 1), 1);
+ }
+}
+
+TEST(LlvmLibcTypeTraitsTest, invoke_result) {
+ using namespace invoke_detail;
+ EXPECT_TRUE(
+ (cpp::is_same_v<cpp::invoke_result_t<decltype(&A::apply), A>, void>));
+ EXPECT_TRUE(
+ (cpp::is_same_v<cpp::invoke_result_t<decltype(&A::apply), B>, void>));
+ EXPECT_TRUE(
+ (cpp::is_same_v<cpp::invoke_result_t<decltype(&free_function)>, void>));
+ EXPECT_TRUE(
+ (cpp::is_same_v<cpp::invoke_result_t<decltype(&free_function_return_5)>,
+ int>));
+ EXPECT_TRUE((cpp::is_same_v<
+ cpp::invoke_result_t<decltype(&free_function_passtrough), int>,
+ int>));
+ EXPECT_TRUE(
+ (cpp::is_same_v<
+ cpp::invoke_result_t<decltype(&Delegate::ptr), Delegate, int>, int>));
+ {
+ auto lambda = []() {};
+ EXPECT_TRUE((cpp::is_same_v<cpp::invoke_result_t<decltype(lambda)>, void>));
+ }
+ {
+ auto lambda = []() { return 0; };
+ EXPECT_TRUE((cpp::is_same_v<cpp::invoke_result_t<decltype(lambda)>, int>));
+ }
+ {
+ auto lambda = [](int) -> double { return 0; };
+ EXPECT_TRUE(
+ (cpp::is_same_v<cpp::invoke_result_t<decltype(lambda), int>, double>));
+ }
+}
+
using IntegralAndFloatingTypes =
testing::TypeList<bool, char, short, int, long, long long, unsigned char,
unsigned short, unsigned int, unsigned long,
diff --git a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
index 17e4913749d51c6..06cabc015decf30 100644
--- a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
@@ -295,6 +295,8 @@ libc_support_library(
"src/__support/CPP/type_traits/enable_if.h",
"src/__support/CPP/type_traits/false_type.h",
"src/__support/CPP/type_traits/integral_constant.h",
+ "src/__support/CPP/type_traits/invoke.h",
+ "src/__support/CPP/type_traits/invoke_result.h",
"src/__support/CPP/type_traits/is_arithmetic.h",
"src/__support/CPP/type_traits/is_array.h",
"src/__support/CPP/type_traits/is_base_of.h",
@@ -333,6 +335,7 @@ libc_support_library(
"src/__support/CPP/type_traits/type_identity.h",
"src/__support/CPP/type_traits/void_t.h",
"src/__support/CPP/utility/declval.h",
+ "src/__support/CPP/utility/forward.h",
],
deps = [
":__support_macros_attributes",
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