[PATCH] D102631: Allow incomplete template types in unique_function arguments
Fehr Mathieu via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Wed May 19 08:55:00 PDT 2021
math-fehr updated this revision to Diff 346479.
math-fehr added a comment.
Address comments.
- Rename AdjustedParamT to AdjustedParamTBase and define AdjustedParamT alias
- Specialize also for rvalues
- Add static assert to make intentions clear
- Add rvalue tests, and renamed class to better express meaning
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D102631/new/
https://reviews.llvm.org/D102631
Files:
llvm/include/llvm/ADT/FunctionExtras.h
llvm/unittests/ADT/FunctionExtrasTest.cpp
Index: llvm/unittests/ADT/FunctionExtrasTest.cpp
===================================================================
--- llvm/unittests/ADT/FunctionExtrasTest.cpp
+++ llvm/unittests/ADT/FunctionExtrasTest.cpp
@@ -273,4 +273,22 @@
EXPECT_EQ("string", returns([] { return "hello"; }));
}
+// A forward declared type, and a templated type.
+class Incomplete;
+template <typename T> class Templated { T A; };
+
+// Check that we can define unique_function that have references to
+// incomplete types, even if those types are templated over an
+// incomplete type.
+TEST(UniqueFunctionTest, IncompleteTypes) {
+ unique_function<void(Templated<Incomplete> &&)>
+ IncompleteArgumentRValueReference;
+ unique_function<void(Templated<Incomplete> &)>
+ IncompleteArgumentLValueReference;
+ unique_function<void(Templated<Incomplete> *)> IncompleteArgumentPointer;
+ unique_function<Templated<Incomplete> &()> IncompleteResultLValueReference;
+ unique_function<Templated<Incomplete> && ()> IncompleteResultRValueReference2;
+ unique_function<Templated<Incomplete> *()> IncompleteResultPointer;
+}
+
} // anonymous namespace
Index: llvm/include/llvm/ADT/FunctionExtras.h
===================================================================
--- llvm/include/llvm/ADT/FunctionExtras.h
+++ llvm/include/llvm/ADT/FunctionExtras.h
@@ -89,13 +89,24 @@
// The heuristic used is related to common ABI register passing conventions.
// It doesn't have to be exact though, and in one way it is more strict
// because we want to still be able to observe either moves *or* copies.
+ template <typename T> struct AdjustedParamTBase {
+ static_assert(!std::is_reference<T>::value,
+ "references should be handled by template specialization");
+ using type = typename std::conditional<
+ llvm::is_trivially_copy_constructible<T>::value &&
+ llvm::is_trivially_move_constructible<T>::value &&
+ IsSizeLessThanThresholdT<T>::value,
+ T, T &>::type;
+ };
+
+ // This specialization ensures that 'AdjustedParam<V<T>&>' or
+ // 'AdjustedParam<V<T>&&>' does not trigger a compile-time error when 'T' is
+ // an incomplete type and V a templated type.
+ template <typename T> struct AdjustedParamTBase<T &> { using type = T &; };
+ template <typename T> struct AdjustedParamTBase<T &&> { using type = T &; };
+
template <typename T>
- using AdjustedParamT = typename std::conditional<
- !std::is_reference<T>::value &&
- llvm::is_trivially_copy_constructible<T>::value &&
- llvm::is_trivially_move_constructible<T>::value &&
- IsSizeLessThanThresholdT<T>::value,
- T, T &>::type;
+ using AdjustedParamT = typename AdjustedParamTBase<T>::type;
// The type of the erased function pointer we use as a callback to dispatch to
// the stored callable when it is trivial to move and destroy.
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