From 66455b708ae3f8d94a3601087e73394cab5977ca Mon Sep 17 00:00:00 2001
From: Tony Wasserka <neobrain@users.noreply.github.com>
Date: Thu, 9 Jul 2026 17:17:19 +0200
Subject: [PATCH] CodeCache: Switch between 32-/64-bit compilers during cache
 generation

---
 Source/Tools/FEXOfflineCompiler/CMakeLists.txt |  5 +++++
 Source/Tools/FEXOfflineCompiler/Main.cpp       | 18 +++++++++++++-----
 Source/Windows/Common/ImageTracker.cpp         |  5 +++--
 3 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/Source/Tools/FEXOfflineCompiler/CMakeLists.txt b/Source/Tools/FEXOfflineCompiler/CMakeLists.txt
index 33f337043..5ce74795d 100644
--- a/Source/Tools/FEXOfflineCompiler/CMakeLists.txt
+++ b/Source/Tools/FEXOfflineCompiler/CMakeLists.txt
@@ -9,6 +9,11 @@ target_link_libraries(FEXOfflineCompiler PRIVATE
   fmt::fmt)
 
 if (MINGW)
+  if (ARCHITECTURE_arm64ec)
+    set_target_properties(FEXOfflineCompiler PROPERTIES OUTPUT_NAME "FEXOfflineCompiler64")
+  else()
+    set_target_properties(FEXOfflineCompiler PROPERTIES OUTPUT_NAME "FEXOfflineCompiler32")
+  endif()
   patch_library_wine(FEXOfflineCompiler)
   target_include_directories(FEXOfflineCompiler PRIVATE
     "${CMAKE_SOURCE_DIR}/Source/Windows/include/"
diff --git a/Source/Tools/FEXOfflineCompiler/Main.cpp b/Source/Tools/FEXOfflineCompiler/Main.cpp
index 4b469f13f..e969af057 100644
--- a/Source/Tools/FEXOfflineCompiler/Main.cpp
+++ b/Source/Tools/FEXOfflineCompiler/Main.cpp
@@ -51,6 +51,14 @@ static std::unique_ptr<FEX::Windows::OvercommitTracker> OvercommitTracker;
 #endif
 static FEXCore::Core::InternalThreadState* Thread = nullptr;
 
+#ifdef _WIN32
+#ifdef _M_ARM64EC
+const bool Is64BitCompiler = true;
+#else
+const bool Is64BitCompiler = false;
+#endif
+#endif
+
 #ifdef _WIN32
 class AOTSyscallHandler : public FEXCore::HLE::SyscallHandler {
 #else
@@ -396,10 +404,8 @@ static std::optional<std::string> GenerateSingleCache(FEXCore::ExecutableFileInf
     return std::nullopt;
   }
   const bool Is64Bit = Loader.Is64BitMode();
-#elif defined(_M_ARM64EC)
-  const bool Is64Bit = true;
 #else
-  const bool Is64Bit = false;
+  const bool Is64Bit = Is64BitCompiler;
 #endif
   FEXCore::Config::Set(FEXCore::Config::CONFIG_IS64BIT_MODE, Is64Bit ? "1" : "0");
 
@@ -774,11 +780,13 @@ static int ProcessAll() {
     }
 
 #ifdef _WIN32
-    // For WoA, spawn a subprocess for each cache generation run to
-    // ensure robustness against JIT crashes.
+    // For WoA, spawn a subprocess for each cache generation run.
+    // This ensures robustness and allows for switching FEXOfflineCompiler between WoW64 and ARM64EC.
     char SelfPathRaw[PATH_MAX];
     GetModuleFileNameA(nullptr, SelfPathRaw, sizeof(SelfPathRaw));
     std::string SelfPath = SelfPathRaw;
+    auto NewExecName = fmt::format("FEXOfflineCompiler{}.exe", ExecutableIt->second.ExecutableBitness.value());
+    SelfPath.replace(SelfPath.size() - NewExecName.size(), NewExecName.size(), NewExecName);
 #endif
 
     fmt::println("\nChecking caches for executable {}", ExecutableIt->second.Filename);
diff --git a/Source/Windows/Common/ImageTracker.cpp b/Source/Windows/Common/ImageTracker.cpp
index 42c4c87b0..4d6c0dd59 100644
--- a/Source/Windows/Common/ImageTracker.cpp
+++ b/Source/Windows/Common/ImageTracker.cpp
@@ -227,8 +227,9 @@ int ImageTracker::OpenCodeMapFile() {
 
 void ImageTracker::LoadAOTImages(MappedImageInfo& ImageInfo) {
   // Don't attempt cache loading for FEXOfflineCompiler itself
-  static bool IsFOC = ImageInfo.Info.Filename.ends_with("fexofflinecompiler.exe");
-  if (IsFOC) {
+  static bool IsFOC32 = ImageInfo.Info.Filename.ends_with("fexofflinecompiler32.exe");
+  static bool IsFOC64 = ImageInfo.Info.Filename.ends_with("fexofflinecompiler64.exe");
+  if (IsFOC32 || IsFOC64) {
     return;
   }