[gcc r14-5598] c++: Set DECL_CONTEXT for __cxa_thread_atexit [PR99187]

[Nathan Sidwell <nathan@gcc.gnu.org>]

https://gcc.gnu.org/g:eaeaad3fcac4d7a30b5a256410cb59fa1a3fa9dd

commit r14-5598-geaeaad3fcac4d7a30b5a256410cb59fa1a3fa9dd
Author: Nathaniel Shead <nathanieloshead@gmail.com>
Date:   Fri Nov 17 08:39:53 2023 +1100

    c++: Set DECL_CONTEXT for __cxa_thread_atexit [PR99187]
    
    Modules streaming requires DECL_CONTEXT to be set on declarations that
    are streamed. This ensures that __cxa_thread_atexit is given translation
    unit context much like is already done with many other support
    functions.
    
            PR c++/99187
    
    gcc/cp/ChangeLog:
    
            * cp-tree.h (enum cp_tree_index): Add CPTI_THREAD_ATEXIT.
            (thread_atexit_node): New.
            * decl.cc (get_thread_atexit_node): Cache in thread_atexit_node.
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/modules/pr99187.C: New test.
    
    Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
    Signed-off-by: Nathan Sidwell <nathan@acm.org>

Diff:
---
 gcc/cp/cp-tree.h                       |  4 ++++
 gcc/cp/decl.cc                         | 15 +++++++++++++--
 gcc/testsuite/g++.dg/modules/pr99187.C | 10 ++++++++++
 3 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 1fa710d7154..c7a1cf610c8 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -231,6 +231,7 @@ enum cp_tree_index
     CPTI_RETHROW_FN,
     CPTI_ATEXIT_FN_PTR_TYPE,
     CPTI_ATEXIT,
+    CPTI_THREAD_ATEXIT,
     CPTI_DSO_HANDLE,
     CPTI_DCAST,
 
@@ -375,6 +376,9 @@ extern GTY(()) tree cp_global_trees[CPTI_MAX];
 /* A pointer to `std::atexit'.  */
 #define atexit_node			cp_global_trees[CPTI_ATEXIT]
 
+/* A pointer to `__cxa_thread_atexit'.  */
+#define thread_atexit_node		cp_global_trees[CPTI_THREAD_ATEXIT]
+
 /* A pointer to `__dso_handle'.  */
 #define dso_handle_node			cp_global_trees[CPTI_DSO_HANDLE]
 
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index b8e1098d482..e6f75d771e0 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -9593,6 +9593,9 @@ get_atexit_node (void)
 static tree
 get_thread_atexit_node (void)
 {
+  if (thread_atexit_node)
+    return thread_atexit_node;
+
   /* The declaration for `__cxa_thread_atexit' is:
 
      int __cxa_thread_atexit (void (*)(void *), void *, void *) */
@@ -9601,10 +9604,18 @@ get_thread_atexit_node (void)
 					   ptr_type_node, ptr_type_node,
 					   NULL_TREE);
 
-  /* Now, build the function declaration.  */
+  /* Now, build the function declaration, as with __cxa_atexit.  */
+  unsigned flags = push_abi_namespace ();
   tree atexit_fndecl = build_library_fn_ptr ("__cxa_thread_atexit", fn_type,
 					     ECF_LEAF | ECF_NOTHROW);
-  return decay_conversion (atexit_fndecl, tf_warning_or_error);
+  DECL_CONTEXT (atexit_fndecl) = FROB_CONTEXT (current_namespace);
+  DECL_SOURCE_LOCATION (atexit_fndecl) = BUILTINS_LOCATION;
+  atexit_fndecl = pushdecl (atexit_fndecl, /*hiding=*/true);
+  pop_abi_namespace (flags);
+  mark_used (atexit_fndecl);
+  thread_atexit_node = decay_conversion (atexit_fndecl, tf_warning_or_error);
+
+  return thread_atexit_node;
 }
 
 /* Returns the __dso_handle VAR_DECL.  */
diff --git a/gcc/testsuite/g++.dg/modules/pr99187.C b/gcc/testsuite/g++.dg/modules/pr99187.C
new file mode 100644
index 00000000000..7f707e0c703
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/pr99187.C
@@ -0,0 +1,10 @@
+// { dg-additional-options "-fmodules-ts" }
+// { dg-module-cmi pr99187 }
+
+export module pr99187;
+
+export struct A { ~A() {} };
+
+export inline void f() {
+  static thread_local A a;
+}