Thunks/GL: Use guest-callable host function pointers to implement glXGetProcAddress

ThunkLibs/GuestLibs/CMakeLists.txt

@@ -112,7 +112,7 @@ add_guest_lib(asound)
 generate(libEGL ${CMAKE_CURRENT_SOURCE_DIR}/../libEGL/libEGL_interface.cpp thunks function_packs function_packs_public)
 add_guest_lib(EGL)
 
-generate(libGL ${CMAKE_CURRENT_SOURCE_DIR}/../libGL/libGL_interface.cpp thunks function_packs function_packs_public)
+generate(libGL ${CMAKE_CURRENT_SOURCE_DIR}/../libGL/libGL_interface.cpp thunks function_packs function_packs_public symbol_list)
 add_guest_lib(GL)
 
 # disabled for now, headers are platform specific

ThunkLibs/libGL/libGL_Guest.cpp

@@ -8,36 +8,56 @@ $end_info$
 #define GL_GLEXT_PROTOTYPES 1
 #define GLX_GLXEXT_PROTOTYPES 1
 
-#include "glcorearb.h"
-
 #include <GL/glx.h>
 #include <GL/glxext.h>
 #include <GL/gl.h>
 #include <GL/glext.h>
+
+#undef GL_ARB_viewport_array
+#include "glcorearb.h"
+
 #include <stdio.h>
-#include <cstring>
+#include <cstdlib>
+#include <functional>
+#include <string_view>
+#include <unordered_map>
 
 #include "common/Guest.h"
 
 #include "thunks.inl"
 #include "function_packs.inl"
 #include "function_packs_public.inl"
+#include "symbol_list.inl"
 
 typedef void voidFunc();
 
+// Maps OpenGL API function names to the address of a guest function which is
+// linked to the corresponding host function pointer
+const std::unordered_map<std::string_view, uintptr_t /* guest function address */> HostPtrInvokers =
+    std::invoke([]() {
+#define PAIR(name, unused) Ret[#name] = reinterpret_cast<uintptr_t>(GetCallerForHostThunkFromRuntimePointer<fexthunks_libGL_hostcall_##name>(name));
+        std::unordered_map<std::string_view, uintptr_t> Ret;
+        FOREACH_internal_SYMBOL(PAIR)
+        return Ret;
+#undef PAIR
+    });
+
 extern "C" {
 	voidFunc *glXGetProcAddress(const GLubyte *procname) {
+    auto Ret = fexfn_pack_glXGetProcAddress(procname);
+    if (!Ret) {
+        return nullptr;
+    }
 
-        for (int i = 0; internal_symtable[i].name; i++) {
-            if (strcmp(internal_symtable[i].name, (const char*)procname) == 0) {
-				// for debugging
-                //printf("glXGetProcAddress: looked up %s %s %p %p\n", procname, internal_symtable[i].name, internal_symtable[i].fn, &glXGetProcAddress);
-                return internal_symtable[i].fn;
-			}
-		}
+    auto TargetFuncIt = HostPtrInvokers.find(reinterpret_cast<const char*>(procname));
+    if (TargetFuncIt == HostPtrInvokers.end()) {
+      // Extension found in host but not in our interface definition => treat as fatal error
+      fprintf(stderr, "glXGetProcAddress: not found %s\n", procname);
+      __builtin_trap();
+    }
 
-		printf("glXGetProcAddress: not found %s\n", procname);
-		return nullptr;
+    LinkAddressToFunction((uintptr_t)Ret, TargetFuncIt->second);
+    return Ret;
 	}
 
 	voidFunc *glXGetProcAddressARB(const GLubyte *procname) {
@@ -45,4 +65,4 @@ extern "C" {
 	}
 }
 
-LOAD_LIB(libGL)
+LOAD_LIB(libGL)

ThunkLibs/libGL/libGL_Host.cpp

@@ -18,6 +18,8 @@ $end_info$
 #include <GL/gl.h>
 #include <GL/glext.h>
 
+#include <cstdlib>
+
 #include "common/Host.h"
 
 void fexfn_impl_libGL_glDebugMessageCallbackAMD_internal(GLDEBUGPROCAMD, const void*) {

ThunkLibs/libGL/libGL_interface.cpp

@@ -15,6 +15,14 @@ template<auto>
 struct fex_gen_config {
 };
 
+template<> struct fex_gen_config<glXGetProcAddress> : fexgen::custom_guest_entrypoint, fexgen::returns_guest_pointer {};
+
+// Symbols queryable through glXGetProcAddr
+namespace internal {
+template<auto>
+struct fex_gen_config : fexgen::generate_guest_symtable, fexgen::indirect_guest_calls {
+};
+
 template<> struct fex_gen_config<glXQueryCurrentRendererStringMESA> {};
 template<> struct fex_gen_config<glXQueryRendererStringMESA> {};
 template<> struct fex_gen_config<glXGetContextIDEXT> {};
@@ -93,13 +101,6 @@ template<> struct fex_gen_config<glXGetVisualFromFBConfig> {};
 template<> struct fex_gen_config<glXCreateContextAttribsARB> {};
 template<> struct fex_gen_config<glXSwapIntervalEXT> {};
 
-// Symbols exposed through glXGetProcAddr
-namespace internal {
-template<auto>
-struct fex_gen_config : fexgen::generate_guest_symtable {
-    const char* load_host_endpoint_via = "symbolFromGlXGetProcAddr";
-};
-
 template<> struct fex_gen_config<glColorP3ui> {};
 template<> struct fex_gen_config<glColorP3uiv> {};
 template<> struct fex_gen_config<glColorP4ui> {};
@@ -696,9 +697,9 @@ template<> struct fex_gen_config<glCullFace> {};
 template<> struct fex_gen_config<glCullParameterdvEXT> {};
 template<> struct fex_gen_config<glCullParameterfvEXT> {};
 template<> struct fex_gen_config<glCurrentPaletteMatrixARB> {};
-template<> struct fex_gen_config<glDebugMessageCallbackAMD> {};
-template<> struct fex_gen_config<glDebugMessageCallbackARB> {};
-template<> struct fex_gen_config<glDebugMessageCallback> {};
+template<> struct fex_gen_config<glDebugMessageCallbackAMD> : fexgen::callback_stub {};
+template<> struct fex_gen_config<glDebugMessageCallbackARB> : fexgen::callback_stub {};
+template<> struct fex_gen_config<glDebugMessageCallback> : fexgen::callback_stub {};
 template<> struct fex_gen_config<glDebugMessageControlARB> {};
 template<> struct fex_gen_config<glDebugMessageControl> {};
 template<> struct fex_gen_config<glDebugMessageEnableAMD> {};