From 83c2e52ba59519898efa4984de756a799c74b35c Mon Sep 17 00:00:00 2001
From: Tony Wasserka <neobrain@users.noreply.github.com>
Date: Thu, 7 Jul 2022 12:34:00 +0200
Subject: [PATCH] Vulkan: Handle queries for unknown functions more gracefully

---
 ThunkLibs/libvulkan/Guest.cpp | 44 ++++++++++++++++++++++++-----------
 1 file changed, 30 insertions(+), 14 deletions(-)

diff --git a/ThunkLibs/libvulkan/Guest.cpp b/ThunkLibs/libvulkan/Guest.cpp
index 1d3d42846..64a80ada9 100644
--- a/ThunkLibs/libvulkan/Guest.cpp
+++ b/ThunkLibs/libvulkan/Guest.cpp
@@ -36,18 +36,40 @@ const std::unordered_map<std::string_view, uintptr_t /* guest function address *
 #undef PAIR
     });
 
+// This variable controls the behavior of vkGetDevice/InstanceProcAddr for functions we don't know the signature of:
+// - if false (default), we return a nullptr (since the application might have a fallback code path)
+// - if true, we return a stub function that fatally errors upon being called
+constexpr bool stub_unknown_functions = false;
+
+// Fatally erroring function with a thunk-like interface. This is used as a placeholder for unknown Vulkan functions
+[[noreturn]] static void FatalError(void* raw_args) {
+    auto called_function = reinterpret_cast<PackedArguments<void, uintptr_t>*>(raw_args)->a0;
+    fprintf(stderr, "FATAL: Called unknown Vulkan function at address %p\n", reinterpret_cast<void*>(called_function));
+    __builtin_trap();
+}
+
+static PFN_vkVoidFunction MakeGuestCallable(const char* origin, PFN_vkVoidFunction func, const char* name) {
+    auto It = HostPtrInvokers.find(name);
+    if (It == HostPtrInvokers.end()) {
+        fprintf(stderr, "%s: Unknown Vulkan function at address %p: %s\n", origin, func, name);
+        if (stub_unknown_functions) {
+            const auto StubHostPtrInvoker = CallHostThunkFromRuntimePointer<FatalError, void>;
+            LinkAddressToFunction((uintptr_t)func, reinterpret_cast<uintptr_t>(StubHostPtrInvoker));
+            return func;
+        }
+        return nullptr;
+    }
+    fprintf(stderr, "Linking address %p to host invoker %#lx\n", func, It->second);
+    LinkAddressToFunction((uintptr_t)func, It->second);
+    return func;
+}
+
 PFN_vkVoidFunction vkGetDeviceProcAddr(VkDevice a_0,const char* a_1){
     auto Ret = fexfn_pack_vkGetDeviceProcAddr(a_0, a_1);
     if (!Ret) {
         return nullptr;
     }
-    auto It = HostPtrInvokers.find(a_1);
-    if (It == HostPtrInvokers.end() || !It->second) {
-      fprintf(stderr, "\tvkGetDeviceProcAddr: Couldn't find Guest symbol: '%s'\n", a_1);
-      __builtin_trap();
-    }
-    LinkAddressToFunction((uintptr_t)Ret, It->second);
-    return Ret;
+    return MakeGuestCallable(__FUNCTION__, Ret, a_1);
 }
 
 PFN_vkVoidFunction vkGetInstanceProcAddr(VkInstance a_0,const char* a_1){
@@ -58,13 +80,7 @@ PFN_vkVoidFunction vkGetInstanceProcAddr(VkInstance a_0,const char* a_1){
         if (!Ret) {
             return nullptr;
         }
-        auto It = HostPtrInvokers.find(a_1);
-        if (It == HostPtrInvokers.end() || !It->second) {
-          fprintf(stderr, "\tvkGetInstanceProcAddr: Couldn't find Guest symbol: '%s'\n", a_1);
-          __builtin_trap();
-        }
-        LinkAddressToFunction((uintptr_t)Ret, It->second);
-        return Ret;
+        return MakeGuestCallable(__FUNCTION__, Ret, a_1);
     }
 }