diff mbox series

libstdc++: Fix fancy pointer support in linked lists

Message ID 20241209161401.1852965-1-jwakely@redhat.com
State New
Headers show
Series libstdc++: Fix fancy pointer support in linked lists | expand

Commit Message

Jonathan Wakely Dec. 9, 2024, 4:13 p.m. UTC 
The union members I used in the new _Node types for fancy pointers only
work for value types that are trivially default constructible. This
change adds an unsigned char member to the union, so the node's default
constructor is not defined as deleted.

libstdc++-v3/ChangeLog:

	* include/bits/forward_list.h (__fwd_list::_Node): Add trivial
	member to the union.
	* include/bits/stl_list.h (__list::_Node): Likewise.
	* testsuite/23_containers/forward_list/requirements/explicit_instantiation/alloc_ptr.cc:
	Check explicit instantiation of non-trivial value type.
	* testsuite/23_containers/list/requirements/explicit_instantiation/alloc_ptr.cc:
	Likewise.
---

This fixes an oopsie in my recent std::list and std::forward_list
changes.

Tested x86_64-linux.

 libstdc++-v3/include/bits/forward_list.h              |  1 +
 libstdc++-v3/include/bits/stl_list.h                  |  1 +
 .../requirements/explicit_instantiation/alloc_ptr.cc  | 11 +++++++++++
 .../requirements/explicit_instantiation/alloc_ptr.cc  | 11 +++++++++++
 4 files changed, 24 insertions(+)
diff mbox series

Patch

diff --git a/libstdc++-v3/include/bits/forward_list.h b/libstdc++-v3/include/bits/forward_list.h
index f4a53bb4d7e..e650bbaa6de 100644
--- a/libstdc++-v3/include/bits/forward_list.h
+++ b/libstdc++-v3/include/bits/forward_list.h
@@ -425,6 +425,7 @@  namespace __fwdlist
       _Node(_Node&&) = delete;
 
       union {
+	unsigned char _M_uninit{};
 #if ! _GLIBCXX_INLINE_VERSION
 	// For ABI compatibility we need to overalign this member.
 	alignas(__alignof__(value_type)) // XXX GLIBCXX_ABI Deprecated
diff --git a/libstdc++-v3/include/bits/stl_list.h b/libstdc++-v3/include/bits/stl_list.h
index 9f7d27242b6..ca9a2a1f0b9 100644
--- a/libstdc++-v3/include/bits/stl_list.h
+++ b/libstdc++-v3/include/bits/stl_list.h
@@ -291,6 +291,7 @@  namespace __list
       using _Node_ptr = __ptr_rebind<_ValPtr, _Node>;
 
       union {
+	unsigned char _M_uninit{};
 	value_type _M_data;
       };
 
diff --git a/libstdc++-v3/testsuite/23_containers/forward_list/requirements/explicit_instantiation/alloc_ptr.cc b/libstdc++-v3/testsuite/23_containers/forward_list/requirements/explicit_instantiation/alloc_ptr.cc
index 621ff4c652c..e3bf8a13095 100644
--- a/libstdc++-v3/testsuite/23_containers/forward_list/requirements/explicit_instantiation/alloc_ptr.cc
+++ b/libstdc++-v3/testsuite/23_containers/forward_list/requirements/explicit_instantiation/alloc_ptr.cc
@@ -59,6 +59,17 @@  struct Allocator
 
 template class std::forward_list<int, Allocator<int>>;
 
+struct NonTrivial
+{
+  NonTrivial() { }
+  NonTrivial(const NonTrivial&) { }
+  ~NonTrivial() { }
+  bool operator==(const NonTrivial&) const { return true; } // for remove(T)
+  bool operator<(const NonTrivial&) const { return false; } // for sort()
+};
+
+template class std::forward_list<NonTrivial, Allocator<NonTrivial>>;
+
 #include <testsuite_iterators.h>
 
 void
diff --git a/libstdc++-v3/testsuite/23_containers/list/requirements/explicit_instantiation/alloc_ptr.cc b/libstdc++-v3/testsuite/23_containers/list/requirements/explicit_instantiation/alloc_ptr.cc
index d3b2cfe6d92..c52591b3cf8 100644
--- a/libstdc++-v3/testsuite/23_containers/list/requirements/explicit_instantiation/alloc_ptr.cc
+++ b/libstdc++-v3/testsuite/23_containers/list/requirements/explicit_instantiation/alloc_ptr.cc
@@ -57,6 +57,17 @@  struct Allocator
 
 template class std::list<int, Allocator<int>>;
 
+struct NonTrivial
+{
+  NonTrivial() { }
+  NonTrivial(const NonTrivial&) { }
+  ~NonTrivial() { }
+  bool operator==(const NonTrivial&) const { return true; } // for remove(T)
+  bool operator<(const NonTrivial&) const { return false; } // for sort()
+};
+
+template class std::list<NonTrivial, Allocator<NonTrivial>>;
+
 #include <testsuite_iterators.h>
 
 void