GLX: Assign indices to the GLX dispatch functions defined in libGLX.

The dispatch functions in libGLX are now added to the GLX dispatch list just
like vendor-provided dispatch functions would be.

The function name cache in glXGetProcAddress is no longer required for
correctness, because it can look up a locally-defined dispatch stub in the same
list as the vendor-provided stubs.

In addition to simplifying glXGetProcAddress, this allows vendor libraries to
look up all GLX functions by index. In particular, this would allow a vendor
to look up glXDestroyContext, which would let it recover properly if it fails
to add a new context to the context-to-vendor mapping.

src/GLX/libglx.c

@@ -1658,29 +1658,10 @@ PUBLIC void glXSelectEvent(Display *dpy, GLXDrawable draw, unsigned long event_m
     }
 }
 
-typedef struct {
-    GLubyte *procName;
-    __GLXextFuncPtr addr;
-    UT_hash_handle hh;
-} __GLXprocAddressHash;
-
-static DEFINE_INITIALIZED_LKDHASH(__GLXprocAddressHash, __glXProcAddressHash);
-
-#define LOCAL_FUNC_TABLE_ENTRY(func) \
-    { (GLubyte *)#func, (__GLXextFuncPtr)(func) },
-
-/*
- * This helper function initializes the __GLXprocAddressHash with the
- * dispatch functions implemented above.
- */
-void cacheInitializeOnce(void)
+const __GLXlocalDispatchFunction LOCAL_GLX_DISPATCH_FUNCTIONS[] =
 {
-    size_t i;
-    __GLXprocAddressHash *pEntry;
-    const struct {
-        const GLubyte *procName;
-        __GLXextFuncPtr addr;
-    } localFuncTable[] = {
+#define LOCAL_FUNC_TABLE_ENTRY(func) \
+    { #func, (__GLXextFuncPtr)(func) },
         LOCAL_FUNC_TABLE_ENTRY(glXChooseFBConfig)
         LOCAL_FUNC_TABLE_ENTRY(glXChooseVisual)
         LOCAL_FUNC_TABLE_ENTRY(glXCopyContext)
@@ -1724,27 +1705,17 @@ void cacheInitializeOnce(void)
 
         LOCAL_FUNC_TABLE_ENTRY(glXImportContextEXT)
         LOCAL_FUNC_TABLE_ENTRY(glXFreeContextEXT)
-    };
+#undef LOCAL_FUNC_TABLE_ENTRY
+    { NULL, NULL }
+};
 
-    LKDHASH_WRLOCK(__glXProcAddressHash);
+typedef struct {
+    GLubyte *procName;
+    __GLXextFuncPtr addr;
+    UT_hash_handle hh;
+} __GLXprocAddressHash;
 
-    // Initialize the hash table with our locally-exported functions
-
-    for (i = 0; i < ARRAY_LEN(localFuncTable); i++) {
-        pEntry = malloc(sizeof(*pEntry));
-        if (!pEntry) {
-            assert(pEntry);
-            break;
-        }
-        pEntry->procName =
-            (GLubyte *)strdup((const char *)localFuncTable[i].procName);
-        pEntry->addr = localFuncTable[i].addr;
-        HASH_ADD_KEYPTR(hh, _LH(__glXProcAddressHash), pEntry->procName,
-                        strlen((const char *)pEntry->procName), pEntry);
-    }
-    LKDHASH_UNLOCK(__glXProcAddressHash);
-
-}
+static DEFINE_INITIALIZED_LKDHASH(__GLXprocAddressHash, __glXProcAddressHash);
 
 static void CleanupProcAddressEntry(void *unused, __GLXprocAddressHash *pEntry)
 {
@@ -1761,11 +1732,8 @@ static __GLXextFuncPtr __glXGetCachedProcAddress(const GLubyte *procName)
      * If this is the first time GetProcAddress has been called,
      * initialize the hash table with locally-exported functions.
      */
-    static glvnd_once_t cacheInitializeOnceControl = GLVND_ONCE_INIT;
     __GLXprocAddressHash *pEntry = NULL;
 
-    __glvndPthreadFuncs.once(&cacheInitializeOnceControl, cacheInitializeOnce);
-
     LKDHASH_RDLOCK(__glXProcAddressHash);
     HASH_FIND(hh, _LH(__glXProcAddressHash), procName,
               strlen((const char *)procName), pEntry);

src/GLX/libglxmapping.c

@@ -1040,7 +1040,17 @@ __GLXvendorInfo *__glXVendorFromDrawable(Display *dpy, GLXDrawable drawable)
 
 void __glXMappingInit(void)
 {
+    int i;
+
     __glvndWinsysDispatchInit();
+
+    // Add all of the GLX dispatch stubs that are defined in libGLX itself.
+    for (i=0; LOCAL_GLX_DISPATCH_FUNCTIONS[i].name != NULL; i++) {
+        // TODO: Is there any way to recover from a malloc failure here?
+        __glvndWinsysDispatchAllocIndex(
+                LOCAL_GLX_DISPATCH_FUNCTIONS[i].name,
+                LOCAL_GLX_DISPATCH_FUNCTIONS[i].addr);
+    }
 }
 
 /*!

src/GLX/libglxmapping.h

@@ -84,6 +84,17 @@ typedef struct __GLXdisplayInfoRec {
     Bool libglvndExtensionSupported;
 } __GLXdisplayInfo;
 
+typedef struct __GLXlocalDispatchFunctionRec {
+    const char *name;
+    __GLXextFuncPtr addr;
+} __GLXlocalDispatchFunction;
+
+/*!
+ * A NULL-termianted list of GLX dispatch functions that are implemented in
+ * libGLX instead of in any vendor library.
+ */
+extern const __GLXlocalDispatchFunction LOCAL_GLX_DISPATCH_FUNCTIONS[];
+
 /*!
  * Accessor functions used to retrieve the "current" dispatch table for each of
  * the three types of dispatch tables (see libglxabi.h for an explanation of