--- a/python/mozbuild/mozbuild/action/check_binary.py
+++ b/python/mozbuild/mozbuild/action/check_binary.py
@@ -209,18 +209,27 @@ def check_nsmodules(target, binary):
         raise RuntimeError('Could not find NSModules')
 
     def print_symbols(symbols):
         for addr, size, sym in symbols:
             print('%x %d %s' % (addr, size, sym))
 
     symbols = sorted(symbols)
     next_addr = None
+    # MSVC linker, when doing incremental linking, adds padding when
+    # merging sections. Allow there to be more space between the NSModule
+    # symbols, as long as they are in the right order.
+    if buildconfig.substs.get('_MSC_VER') and \
+            buildconfig.substs.get('DEVELOPER_OPTIONS'):
+        sym_cmp = lambda guessed, actual: guessed <= actual
+    else:
+        sym_cmp = lambda guessed, actual: guessed == actual
+
     for addr, size, sym in symbols:
-        if next_addr is not None and next_addr != addr:
+        if next_addr is not None and not sym_cmp(next_addr, addr):
             print_symbols(symbols)
             raise RuntimeError('NSModules are not adjacent')
         next_addr = addr + size
 
     # The mac linker doesn't emit the start/stop symbols in the symbol table.
     # We'll just assume it did the job correctly.
     if get_type(binary) == MACHO:
         return

--- a/xpcom/components/nsComponentManager.cpp
+++ b/xpcom/components/nsComponentManager.cpp
@@ -358,17 +358,20 @@ nsComponentManagerImpl::Init()
 
   InitializeStaticModules();
 
   nsCategoryManager::GetSingleton()->SuppressNotifications(true);
 
   RegisterModule(&kXPCOMModule, nullptr);
 
   for (auto module : AllStaticModules()) {
-    RegisterModule(module, nullptr);
+    if (module) { // On local Windows builds, the list may contain null
+                  // pointers from padding.
+      RegisterModule(module, nullptr);
+    }
   }
 
   for (uint32_t i = 0; i < sExtraStaticModules->Length(); ++i) {
     RegisterModule((*sExtraStaticModules)[i], nullptr);
   }
 
   bool loadChromeManifests = (XRE_GetProcessType() != GeckoProcessType_GPU);
   if (loadChromeManifests) {