loader: Support layers that don't have an extension entrypoint

Change all layers and loader interface to init dispatch tables on
GPA("GetXXXProcAddr").  After that initialization rest of dispatch
tables are inited via unwrapped object using the GPA in the dispatch
table.  This also allows App generated GPA calls that the loader can't resolve
to function correctly.

1 files changed, 18 insertions, 29 deletions

diff --git a/layers/shader_checker.cpp b/layers/shader_checker.cpp
index 9484cd0b..5b66c631 100644
--- a/layers/shader_checker.cpp
+++ b/layers/shader_checker.cpp
@@ -160,7 +160,7 @@ static VkLayerDispatchTable * initLayerTable(const VkBaseLayerObject *devw)
         return it->second;
     }
 
-    layer_initialize_dispatch_table(pTable, (PFN_vkGetDeviceProcAddr) devw->pGPA, (VkDevice) devw->nextObject);
+    layer_initialize_dispatch_table(pTable, devw);
 
     return pTable;
 }
@@ -180,24 +180,11 @@ static VkLayerInstanceDispatchTable * initLayerInstanceTable(const VkBaseLayerOb
         return it->second;
     }
 
-    layer_init_instance_dispatch_table(pTable, (PFN_vkGetInstanceProcAddr) instw->pGPA, (VkInstance) instw->nextObject);
+    layer_init_instance_dispatch_table(pTable, instw);
 
     return pTable;
 }
 
-VK_LAYER_EXPORT VkResult VKAPI vkEnumerateLayers(VkPhysicalDevice physicalDevice, size_t maxStringSize, size_t* pLayerCount, char* const* pOutLayers, void* pReserved)
-{
-    if (pLayerCount == NULL || pOutLayers == NULL || pOutLayers[0] == NULL || pOutLayers[1] == NULL || pReserved == NULL)
-        return VK_ERROR_INVALID_POINTER;
-
-    if (*pLayerCount < 1)
-        return VK_ERROR_INITIALIZATION_FAILED;
-    *pLayerCount = 1;
-    strncpy((char *) pOutLayers[0], "ShaderChecker", maxStringSize);
-    return VK_SUCCESS;
-}
-
-
 #define SHADER_CHECKER_LAYER_EXT_ARRAY_SIZE 2
 static const VkExtensionProperties shaderCheckerExts[SHADER_CHECKER_LAYER_EXT_ARRAY_SIZE] = {
     {
@@ -966,25 +953,27 @@ VK_LAYER_EXPORT void * VKAPI vkGetDeviceProcAddr(VkDevice device, const char* pN
     if (device == NULL)
         return NULL;
 
-    initLayerTable((const VkBaseLayerObject *) device);
-
     loader_platform_thread_once(&g_initOnce, initLayer);
 
+    /* loader uses this to force layer initialization; device object is wrapped */
+    if (!strcmp("vkGetDeviceProcAddr", pName)) {
+        initLayerTable((const VkBaseLayerObject *) device);
+        return (void *) vkGetDeviceProcAddr;
+    }
+
 #define ADD_HOOK(fn)    \
     if (!strncmp(#fn, pName, sizeof(#fn))) \
         return (void *) fn
 
-    ADD_HOOK(vkGetDeviceProcAddr);
     ADD_HOOK(vkCreateShader);
     ADD_HOOK(vkDestroyDevice);
     ADD_HOOK(vkCreateGraphicsPipeline);
     ADD_HOOK(vkCreateGraphicsPipelineDerivative);
 #undef ADD_HOOK
-
-    VkBaseLayerObject* devw = (VkBaseLayerObject *) device;
-    if (devw->pGPA == NULL)
+    VkLayerDispatchTable* pTable = tableMap[(VkBaseLayerObject *)device];
+    if (pTable->GetDeviceProcAddr == NULL)
         return NULL;
-    return devw->pGPA((VkObject) devw->nextObject, pName);
+    return pTable->GetDeviceProcAddr(device, pName);
 }
 
 VK_LAYER_EXPORT void * VKAPI vkGetInstanceProcAddr(VkInstance inst, const char* pName)
@@ -992,22 +981,22 @@ VK_LAYER_EXPORT void * VKAPI vkGetInstanceProcAddr(VkInstance inst, const char*
     if (inst == NULL)
         return NULL;
 
-    initLayerInstanceTable((const VkBaseLayerObject *) inst);
-
     loader_platform_thread_once(&g_initOnce, initLayer);
 
+    if (!strcmp("vkGetInstanceProcAddr", pName)) {
+        initLayerInstanceTable((const VkBaseLayerObject *) inst);
+        return (void *) vkGetInstanceProcAddr;
+    }
 #define ADD_HOOK(fn)    \
     if (!strncmp(#fn, pName, sizeof(#fn))) \
         return (void *) fn
 
-    ADD_HOOK(vkGetInstanceProcAddr);
     ADD_HOOK(vkDestroyInstance);
-    ADD_HOOK(vkEnumerateLayers);
     ADD_HOOK(vkGetGlobalExtensionInfo);
 #undef ADD_HOOK
 
-    VkBaseLayerObject* instw = (VkBaseLayerObject *) inst;
-    if (instw->pGPA == NULL)
+    VkLayerInstanceDispatchTable* pTable = tableInstanceMap[(VkBaseLayerObject *) inst];
+    if (pTable->GetInstanceProcAddr == NULL)
         return NULL;
-    return instw->pGPA((VkObject) instw->nextObject, pName);
+    return pTable->GetInstanceProcAddr(inst, pName);
 }