From 7845dac09a6d316dfe686cb52a6bc0724f2d2b75 Mon Sep 17 00:00:00 2001
From: Roland Conybeare <rconybeare@gmail.com>
Date: Thu, 26 Mar 2026 14:58:14 -0400
Subject: [PATCH] xo-gc stack: + contains() method

---
 xo-alloc2/include/xo/alloc2/gc/ACollector.hpp          | 6 ++++++
 xo-alloc2/include/xo/alloc2/gc/ICollector_Any.hpp      | 1 +
 xo-alloc2/include/xo/alloc2/gc/ICollector_Xfer.hpp     | 3 +++
 xo-alloc2/include/xo/alloc2/gc/RCollector.hpp          | 1 +
 xo-gc/include/xo/gc/detail/ICollector_DX1Collector.hpp | 1 +
 xo-gc/src/gc/ICollector_DX1Collector.cpp               | 6 ++++++
 6 files changed, 18 insertions(+)

diff --git a/xo-alloc2/include/xo/alloc2/gc/ACollector.hpp b/xo-alloc2/include/xo/alloc2/gc/ACollector.hpp
index 63004b7b..6793f499 100644
--- a/xo-alloc2/include/xo/alloc2/gc/ACollector.hpp
+++ b/xo-alloc2/include/xo/alloc2/gc/ACollector.hpp
@@ -43,6 +43,12 @@ namespace xo {
                                         Generation g, role r) const noexcept = 0;
             virtual size_type committed(Copaque d,
                                         Generation g, role r) const noexcept = 0;
+
+            /** true if gc responsible for address @p addr with role @p r
+             **/
+            virtual bool contains(Copaque d,
+                                  role r, const void * addr) const noexcept = 0;
+
             virtual bool is_type_installed(Copaque d,
                                            typeseq tseq) const noexcept = 0;
 
diff --git a/xo-alloc2/include/xo/alloc2/gc/ICollector_Any.hpp b/xo-alloc2/include/xo/alloc2/gc/ICollector_Any.hpp
index 049978aa..ecc8cfc5 100644
--- a/xo-alloc2/include/xo/alloc2/gc/ICollector_Any.hpp
+++ b/xo-alloc2/include/xo/alloc2/gc/ICollector_Any.hpp
@@ -34,6 +34,7 @@ namespace xo {
             [[noreturn]] size_type allocated(Copaque, Generation, role) const noexcept override { _fatal(); }
             [[noreturn]] size_type reserved(Copaque, Generation, role) const noexcept override { _fatal(); }
             [[noreturn]] size_type committed(Copaque, Generation, role) const noexcept override { _fatal(); }
+            [[noreturn]] bool contains(Copaque, role, const void *) const noexcept override { _fatal(); }
             [[noreturn]] bool is_type_installed(Copaque, typeseq) const noexcept override { _fatal(); }
 
             // non-const methods
diff --git a/xo-alloc2/include/xo/alloc2/gc/ICollector_Xfer.hpp b/xo-alloc2/include/xo/alloc2/gc/ICollector_Xfer.hpp
index 6482508f..dd218043 100644
--- a/xo-alloc2/include/xo/alloc2/gc/ICollector_Xfer.hpp
+++ b/xo-alloc2/include/xo/alloc2/gc/ICollector_Xfer.hpp
@@ -44,6 +44,9 @@ namespace xo {
             bool is_type_installed(Copaque d, typeseq tseq) const noexcept override {
                 return I::is_type_installed(_dcast(d), tseq);
             }
+            bool contains(Copaque d, role r, const void * addr) const noexcept override {
+                return I::contains(_dcast(d), r, addr);
+            }
 
             // non-const methods
 
diff --git a/xo-alloc2/include/xo/alloc2/gc/RCollector.hpp b/xo-alloc2/include/xo/alloc2/gc/RCollector.hpp
index 9dc313b6..f63fb4ab 100644
--- a/xo-alloc2/include/xo/alloc2/gc/RCollector.hpp
+++ b/xo-alloc2/include/xo/alloc2/gc/RCollector.hpp
@@ -45,6 +45,7 @@ namespace xo {
             size_type allocated(Generation g, role r) const noexcept { return O::iface()->allocated(O::data(), g, r); }
             size_type reserved(Generation g, role r) const noexcept { return O::iface()->reserved(O::data(), g, r); }
             size_type committed(Generation g, role r) const noexcept { return O::iface()->committed(O::data(), g, r); }
+            bool contains(role r, const void * addr) const noexcept { return O::iface()->contains(O::data(), r, addr); }
             bool is_type_installed(typeseq tseq) const noexcept { return O::iface()->is_type_installed(O::data(), tseq); }
 
             bool install_type(const AGCObject & iface) { return O::iface()->install_type(O::data(), iface); }
diff --git a/xo-gc/include/xo/gc/detail/ICollector_DX1Collector.hpp b/xo-gc/include/xo/gc/detail/ICollector_DX1Collector.hpp
index 02c0902d..fe7bb015 100644
--- a/xo-gc/include/xo/gc/detail/ICollector_DX1Collector.hpp
+++ b/xo-gc/include/xo/gc/detail/ICollector_DX1Collector.hpp
@@ -44,6 +44,7 @@ namespace xo {
             static size_type reserved(const DX1Collector & d, Generation g, role r);
             static size_type committed(const DX1Collector & d, Generation g, role r);
             static bool is_type_installed(const DX1Collector & d, typeseq tseq);
+            static bool contains(const DX1Collector & d, role r, const void * addr);
 
             static bool install_type(DX1Collector & d, const AGCObject & iface);
             static void add_gc_root_poly(DX1Collector & d, obj<AGCObject> * p_root);
diff --git a/xo-gc/src/gc/ICollector_DX1Collector.cpp b/xo-gc/src/gc/ICollector_DX1Collector.cpp
index 09ec8bab..5503d429 100644
--- a/xo-gc/src/gc/ICollector_DX1Collector.cpp
+++ b/xo-gc/src/gc/ICollector_DX1Collector.cpp
@@ -47,6 +47,12 @@ namespace xo {
             return stat_helper(d, &DArena::committed, g, r);
         }
 
+        bool
+        ICollector_DX1Collector::contains(const DX1Collector & d, role r, const void * addr)
+        {
+            return d.contains(r, addr);
+        }
+
         bool
         ICollector_DX1Collector::is_type_installed(const DX1Collector & d, typeseq tseq)
         {