Add compatibility bug for RTSS when querying for vkCreateDevice

The Riva Tuner Statistics Server (RTSS) layer depenended upon a loader bug
which was to allow layers to query vkCreateDevice from loader_gpa_instance_terminator
with a NULL VkInstance handle. Since this bug has been in the loader since pretty
much the start of Vulkan, it is infeasible to fix. For that reason the
inconsistency with the spec is preserved.

diff --git a/loader/loader.c b/loader/loader.c
index 7e3627d..de5c413 100644 (file)
--- a/loader/loader.c
+++ b/loader/loader.c
@@ -4259,6 +4259,15 @@ VKAPI_ATTR PFN_vkVoidFunction VKAPI_CALL loader_gpa_instance_terminator(VkInstan
         return (PFN_vkVoidFunction)terminator_CreateInstance;
     }
 
+    // While the spec is very clear that quering vkCreateDevice requires a valid VkInstance, because the loader allowed querying
+    // with a NULL VkInstance handle for a long enough time, it is impractical to fix this bug in the loader
+
+    // As such, this is a bug to maintain compatibility for the RTSS layer (Riva Tuner Statistics Server) but may
+    // be dependend upon by other layers out in the wild.
+    if (!strcmp(pName, "vkCreateDevice")) {
+        return (PFN_vkVoidFunction)terminator_CreateDevice;
+    }
+
     // inst is not wrapped
     if (inst == VK_NULL_HANDLE) {
         return NULL;
@@ -4270,10 +4279,6 @@ VKAPI_ATTR PFN_vkVoidFunction VKAPI_CALL loader_gpa_instance_terminator(VkInstan
 
     if (disp_table == NULL) return NULL;
 
-    if (!strcmp(pName, "vkCreateDevice")) {
-        return (PFN_vkVoidFunction)terminator_CreateDevice;
-    }
-
     // The VK_EXT_debug_utils functions need a special case here so the terminators can still be found from
     // vkGetInstanceProcAddr This is because VK_EXT_debug_utils is an instance level extension with device level functions, and
     // is 'supported' by the loader.