From 5e0bd5f0c830536cd598c4edb9715a3e69c4f7e6 Mon Sep 17 00:00:00 2001
From: Tyler Veness <calcmogul@gmail.com>
Date: Tue, 9 Jul 2024 22:03:08 -0700
Subject: [PATCH] [upstream_utils] Upgrade Sleipnir to avoid pool allocator
 crash on Windows

---
 upstream_utils/update_sleipnir.py             |  4 ++--
 .../include/sleipnir/autodiff/Expression.hpp  | 24 +++++++++++++++----
 2 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/upstream_utils/update_sleipnir.py b/upstream_utils/update_sleipnir.py
index de152f6e4fe..4b783c82bab 100755
--- a/upstream_utils/update_sleipnir.py
+++ b/upstream_utils/update_sleipnir.py
@@ -15,8 +15,8 @@
 def main():
     upstream_root = clone_repo(
         "https://github.com/SleipnirGroup/Sleipnir",
-        # main on 2024-07-05
-        "b90f89d343379dd8dc88f22e0462eb7b59006b2c",
+        # main on 2024-07-09
+        "b6ffa2d4fdb99cab1bf79491f715a6a9a86633b5",
         shallow=False,
     )
     wpilib_root = get_repo_root()
diff --git a/wpimath/src/main/native/thirdparty/sleipnir/include/sleipnir/autodiff/Expression.hpp b/wpimath/src/main/native/thirdparty/sleipnir/include/sleipnir/autodiff/Expression.hpp
index 2be666e7c87..bdbeb473022 100644
--- a/wpimath/src/main/native/thirdparty/sleipnir/include/sleipnir/autodiff/Expression.hpp
+++ b/wpimath/src/main/native/thirdparty/sleipnir/include/sleipnir/autodiff/Expression.hpp
@@ -20,6 +20,14 @@
 
 namespace sleipnir::detail {
 
+// The global pool allocator uses a thread-local static pool resource, which
+// isn't guaranteed to be initialized properly across DLL boundaries on Windows
+#ifdef _WIN32
+inline constexpr bool kUsePoolAllocator = false;
+#else
+inline constexpr bool kUsePoolAllocator = true;
+#endif
+
 struct SLEIPNIR_DLLEXPORT Expression;
 
 inline void IntrusiveSharedPtrIncRefCount(Expression* expr);
@@ -38,8 +46,12 @@ using ExpressionPtr = IntrusiveSharedPtr<Expression>;
  */
 template <typename... Args>
 static ExpressionPtr MakeExpressionPtr(Args&&... args) {
-  return AllocateIntrusiveShared<Expression>(GlobalPoolAllocator<Expression>(),
-                                             std::forward<Args>(args)...);
+  if constexpr (kUsePoolAllocator) {
+    return AllocateIntrusiveShared<Expression>(
+        GlobalPoolAllocator<Expression>(), std::forward<Args>(args)...);
+  } else {
+    return MakeIntrusiveShared<Expression>(std::forward<Args>(args)...);
+  }
 }
 
 /**
@@ -437,9 +449,11 @@ inline void IntrusiveSharedPtrDecRefCount(Expression* expr) {
 
       // Not calling the destructor here is safe because it only decrements
       // refcounts, which was already done above.
-      auto alloc = GlobalPoolAllocator<Expression>();
-      std::allocator_traits<decltype(alloc)>::deallocate(alloc, elem,
-                                                         sizeof(Expression));
+      if constexpr (kUsePoolAllocator) {
+        auto alloc = GlobalPoolAllocator<Expression>();
+        std::allocator_traits<decltype(alloc)>::deallocate(alloc, elem,
+                                                           sizeof(Expression));
+      }
     }
   }
 }