2 files changed, 19 insertions, 0 deletions
diff --git a/xpcom/build/PoisonIOInterposerMac.cpp b/xpcom/build/PoisonIOInterposerMac.cpp
index 21eca58757..46dc751221 100644
--- a/xpcom/build/PoisonIOInterposerMac.cpp
+++ b/xpcom/build/PoisonIOInterposerMac.cpp
@@ -328,10 +328,17 @@ void InitPoisonIOInterposer() {
     if (!d->Function) {
       continue;
     }
+
+    // Disable the interposer on arm64 until there's
+    // a mach_override_ptr implementation.
 #ifndef __aarch64__
+    // Temporarily disable the interposer on macOS x64
+    // while dynamic code disablement rides the trains.
+#  ifdef MOZ_INTERPOSER_FORCE_MACOS_X64
     DebugOnly<mach_error_t> t =
         mach_override_ptr(d->Function, d->Wrapper, &d->Buffer);
     MOZ_ASSERT(t == err_none);
+#  endif  // MOZ_INTERPOSER_FORCE_MACOS_X64
 #endif
   }
 }
diff --git a/xpcom/build/XPCOMInit.cpp b/xpcom/build/XPCOMInit.cpp
index 4d6572a501..6275ca9c53 100644
--- a/xpcom/build/XPCOMInit.cpp
+++ b/xpcom/build/XPCOMInit.cpp
@@ -233,6 +233,11 @@ static void InitializeJS() {
   JS::SetAVXEnabled(mozilla::StaticPrefs::javascript_options_wasm_simd_avx());
 #endif
 
+  if (XRE_IsParentProcess() &&
+      mozilla::StaticPrefs::javascript_options_main_process_disable_jit()) {
+    JS::DisableJitBackend();
+  }
+
   // Set all JS::Prefs.
   SET_JS_PREFS_FROM_BROWSER_PREFS;
 
@@ -320,6 +325,8 @@ NS_InitXPCOM(nsIServiceManager** aResult, nsIFile* aBinDirectory,
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
+
+  // Initialise the profiler
   AUTO_PROFILER_INIT2;
 
   // Set up the timer globals/timer thread
@@ -459,6 +466,11 @@ NS_InitXPCOM(nsIServiceManager** aResult, nsIFile* aBinDirectory,
   // to the directory service.
   nsDirectoryService::gService->RegisterCategoryProviders();
 
+  // Now that both the profiler and directory services have been started
+  // we can find the download directory, where the profiler can write
+  // profiles if necessary
+  profiler_lookup_download_directory();
+
   // Init mozilla::SharedThreadPool (which needs the service manager).
   mozilla::SharedThreadPool::InitStatics();