From 2bcbfe8747b5f525523b6a0713cc2a8b463977c8 Mon Sep 17 00:00:00 2001
From: Ryan Houdek <Sonicadvance1@gmail.com>
Date: Sun, 19 Oct 2025 14:05:53 -0700
Subject: [PATCH] Windows: rpmalloc

---
 CMakeLists.txt                          |  2 +-
 FEXCore/Source/Utils/AllocatorHooks.cpp | 28 +++----------------------
 Source/Windows/ARM64EC/Module.cpp       |  1 +
 Source/Windows/Common/CRT/CRT.cpp       |  5 +++++
 4 files changed, 10 insertions(+), 26 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c7453c5a5..f3480b6ee 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -322,7 +322,7 @@ endif()
 if (ENABLE_FEX_ALLOCATOR)
   # The rpmalloc subproject that all FEXCore fextl objects allocate through.
   add_subdirectory(External/rpmalloc/)
-elseif (NOT MINGW_BUILD)
+elseif (NOT MINGW)
   message (STATUS
     " FEX allocator is disabled!\n"
     " This is not a recommended configuration!\n"
diff --git a/FEXCore/Source/Utils/AllocatorHooks.cpp b/FEXCore/Source/Utils/AllocatorHooks.cpp
index b800c8a9b..87e38d51f 100644
--- a/FEXCore/Source/Utils/AllocatorHooks.cpp
+++ b/FEXCore/Source/Utils/AllocatorHooks.cpp
@@ -82,6 +82,7 @@ void InitializeThread() {
   rpmalloc_thread_initialize();
 }
 
+#ifndef _WIN32
 [[nodiscard]]
 constexpr uint64_t AlignUp(uint64_t value, uint64_t size) {
   return value + (size - value % size) % size;
@@ -95,9 +96,6 @@ static void* FEX_rp_mmap(size_t size, size_t alignment, size_t* offset, size_t*
   }
 
   size_t map_size = AlignUp(size + alignment, global_config.page_size);
-#ifdef _WIN32
-  auto ptr = VirtualAlloc(0, map_size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
-#else
   auto ptr = fex_mmap_hook(0, map_size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 
   if (ptr == MAP_FAILED) {
@@ -112,7 +110,6 @@ static void* FEX_rp_mmap(size_t size, size_t alignment, size_t* offset, size_t*
 #endif
     prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, ptr, map_size, global_config.page_name);
   }
-#endif
 
   if (ptr == nullptr) {
     fprintf(stderr, "Failed to map VMA region.");
@@ -132,17 +129,7 @@ static void* FEX_rp_mmap(size_t size, size_t alignment, size_t* offset, size_t*
 }
 
 static void FEX_rp_memory_commit(void* address, size_t size) {
-  if (global_config.disable_decommit) {
-    return;
-  }
-
-#ifdef _WIN32
-  if (!VirtualAlloc(address, size, MEM_COMMIT, PAGE_READWRITE)) {
-#else
-  if (false) {
-#endif
-    fprintf(stderr, "Failed to commit VMA region.");
-  }
+  // NOP-implementation.
 }
 
 static void FEX_rp_memory_decommit(void* address, size_t size) {
@@ -150,33 +137,23 @@ static void FEX_rp_memory_decommit(void* address, size_t size) {
     return;
   }
 
-#ifdef _WIN32
-  if (!VirtualFree(address, size, MEM_DECOMMIT)) {
-#else
   if (madvise(address, size, MADV_DONTNEED)) {
-#endif
     fprintf(stderr, "Failed to decommit VMA region.");
   }
 }
 
 static void FEX_rp_memory_unmap(void* address, size_t offset, size_t mapped_size) {
   address = pointer_offset(address, -(int32_t)offset);
-#ifdef _WIN32
-  ::VirtualFree(address, mapped_size, MEM_RELEASE);
-#else
   int Result = fex_munmap_hook(address, mapped_size);
   if (Result == -1) {
     fprintf(stderr, "Failed to unmap VMA region.");
   }
-#endif
 #undef pointer_offset
 }
 
 void SetupAllocatorHooks(mmap_hook_type MMapHook, munmap_hook_type MunmapHook) {
-#ifndef _WIN32
   fex_mmap_hook = MMapHook;
   fex_munmap_hook = MunmapHook;
-#endif
 }
 
 static rpmalloc_interface_t global_interface {
@@ -194,6 +171,7 @@ void InitializeAllocator(size_t PageSize) {
   rp_mmap_hook = FEX_rp_mmap;
   rp_munmap_hook = FEX_rp_memory_unmap;
 }
+#endif
 
 #elif defined(_WIN32)
 #error "Tried building _WIN32 without jemalloc"
diff --git a/Source/Windows/ARM64EC/Module.cpp b/Source/Windows/ARM64EC/Module.cpp
index 49d3f1bce..2384efaff 100644
--- a/Source/Windows/ARM64EC/Module.cpp
+++ b/Source/Windows/ARM64EC/Module.cpp
@@ -1027,6 +1027,7 @@ NTSTATUS ThreadTerm(HANDLE Thread, LONG ExitCode) {
   if (ThreadTID == GetCurrentThreadId()) {
     FEX::Windows::DeinitCRTThread();
   }
+
   return STATUS_SUCCESS;
 }
 
diff --git a/Source/Windows/Common/CRT/CRT.cpp b/Source/Windows/Common/CRT/CRT.cpp
index bf87f1b0f..addea79d8 100644
--- a/Source/Windows/Common/CRT/CRT.cpp
+++ b/Source/Windows/Common/CRT/CRT.cpp
@@ -3,6 +3,7 @@
 #include <windef.h>
 #include <winternl.h>
 #include <wine/debug.h>
+#include <rpmalloc/rpmalloc.h>
 #include "CRT.h"
 
 extern "C" {
@@ -39,6 +40,8 @@ void RunFuncArray(TFuncIt Begin, TFuncIt End, TArgs... Args) {
 
 namespace FEX::Windows {
 void InitCRTProcess() {
+  rpmalloc_initialize(nullptr);
+
   auto GNUCtorBegin = &__CTOR_LIST__[1];
   auto GNUCtorEnd = GNUCtorBegin;
   while (*GNUCtorEnd != nullptr) {
@@ -53,10 +56,12 @@ void InitCRTProcess() {
 }
 
 void InitCRTThread() {
+  rpmalloc_thread_initialize();
   RunFuncArray(&XLA, &XLZ, nullptr, DLL_THREAD_ATTACH, nullptr);
 }
 
 void DeinitCRTThread() {
   RunFuncArray(&XLA, &XLZ, nullptr, DLL_THREAD_DETACH, nullptr);
+  rpmalloc_thread_finalize();
 }
 } // namespace FEX::Windows