Framework: Support vkGetInstanceProcAddr for global functions (#130)

Add support for global function queries for vkGetInstanceProcAddr, 
allows function queries with a nullptr instance handle.

This is not required for the Android loader, but is needed for the 
Khronos standard loader on Linux and Windows.

Author: solidpixel

source_common/framework/manual_functions.cpp

@@ -111,17 +111,38 @@ VkLayerDeviceCreateInfo* getChainInfo(const VkDeviceCreateInfo* pCreateInfo)
 }
 
 /* See header for documentation. */
-PFN_vkVoidFunction getInstanceLayerFunction(const char* name)
+std::pair<bool, PFN_vkVoidFunction> getInstanceLayerFunction(const char* name)
 {
+    const std::array<const char*, 5> globalFunctions {
+        // Supported since Vulkan 1.0
+        "vkCreateInstance",
+        "vkEnumerateInstanceExtensionProperties",
+        "vkEnumerateInstanceLayerProperties",
+        // Supported since Vulkan 1.1
+        "vkEnumerateInstanceVersion",
+        // Supported since Vulkan 1.2
+        "vkGetInstanceProcAddr",
+    };
+
+    bool isGlobal {false};
+    for (const auto* globalName : globalFunctions)
+    {
+        if (!strcmp(globalName, name))
+        {
+            isGlobal = true;
+            break;
+        }
+    }
+
     for (auto& function : instanceIntercepts)
     {
         if (!strcmp(function.name, name))
         {
-            return function.function;
+            return {isGlobal, function.function};
         }
     }
 
-    return nullptr;
+    return {isGlobal, nullptr};
 }
 
 /* See header for documentation. */
@@ -147,12 +168,14 @@ APIVersion getInstanceAPIVersion(PFN_vkGetInstanceProcAddr fpGetProcAddr)
     return { 1, 3 };
 #endif
 
+    // Try to get vkEnumerateInstanceVersion, and assume this is a Vulkan 1.0
+    // feature level if we don't get it ...
     auto fpFunctionRaw = fpGetProcAddr(nullptr, "vkEnumerateInstanceVersion");
     auto fpFunction = reinterpret_cast<PFN_vkEnumerateInstanceVersion>(fpFunctionRaw);
     if (!fpFunction)
     {
-        LAYER_ERR("Failed to get vkEnumerateInstanceVersion()");
-        return {0, 0};
+        LAYER_ERR("Failed to get vkEnumerateInstanceVersion(), assuming Vulkan 1.0");
+        return {1, 0};
     }
 
     uint32_t apiVersion = 0;
@@ -474,9 +497,18 @@ void enableDeviceVkExtImageCompressionControl(Instance& instance,
 /** See Vulkan API for documentation. */
 PFN_vkVoidFunction layer_vkGetInstanceProcAddr_default(VkInstance instance, const char* pName)
 {
-    // Only expose functions that the driver exposes to avoid changing
-    // queryable interface behavior seen by the application
-    auto layerFunction = getInstanceLayerFunction(pName);
+    auto [isGlobal, layerFunction] = getInstanceLayerFunction(pName);
+
+    // Global functions must be exposed and do not require the caller to pass
+    // a valid instance pointer, although it is required to be nullptr in
+    // Vulkan 1.2.193 or later
+    if (isGlobal)
+    {
+        return layerFunction;
+    }
+
+    // For other functions, only expose functions that the driver exposes to
+    // avoid changing queryable interface behavior seen by the application
     if (instance)
     {
         std::unique_lock<std::mutex> lock {g_vulkanLock};

source_common/framework/manual_functions.hpp

@@ -44,6 +44,7 @@
 #include <mutex>
 #include <string>
 #include <thread>
+#include <utility>
 #include <vector>
 
 /**
@@ -85,10 +86,11 @@ PFN_vkVoidFunction getFixedInstanceLayerFunction(const char* name);
  *
  * @param name   The Vulkan function name.
  *
- * @return The layer function pointer, or \c nullptr if the layer doesn't
+ * @return Boolean indicating if this is a globally accessible function, and
+ *         the layer function pointer, or \c nullptr if the layer doesn't
  *         intercept the function.
  */
-PFN_vkVoidFunction getInstanceLayerFunction(const char* name);
+std::pair<bool, PFN_vkVoidFunction> getInstanceLayerFunction(const char* name);
 
 /**
  * @brief Fetch the function for a given dynamic instance entrypoint name.