1 files changed, 60 insertions, 2 deletions

diff --git a/src/mesa/main/context.c b/src/mesa/main/context.c
index 544cc142fde..02875ba2a06 100644
--- a/src/mesa/main/context.c
+++ b/src/mesa/main/context.c
@@ -883,6 +883,19 @@ update_default_objects(struct gl_context *ctx)
 }
 
 
+/* XXX this is temporary and should be removed at some point in the
+ * future when there's a reasonable expectation that the libGL library
+ * contains the _glapi_new_nop_table() and _glapi_set_nop_handler()
+ * functions which were added in Mesa 10.6.
+ */
+#if !defined(_WIN32)
+/* Avoid libGL / driver ABI break */
+#define USE_GLAPI_NOP_FEATURES 0
+#else
+#define USE_GLAPI_NOP_FEATURES 1
+#endif
+
+
 /**
  * This function is called by the glapi no-op functions.  For each OpenGL
  * function/entrypoint there's a simple no-op function.  These "no-op"
@@ -898,6 +911,7 @@ update_default_objects(struct gl_context *ctx)
  *
  * \param name  the name of the OpenGL function
  */
+#if USE_GLAPI_NOP_FEATURES
 static void
 nop_handler(const char *name)
 {
@@ -914,6 +928,7 @@ nop_handler(const char *name)
    }
 #endif
 }
+#endif
 
 
 /**
@@ -923,7 +938,45 @@ nop_handler(const char *name)
 static void GLAPIENTRY
 nop_glFlush(void)
 {
-   /* don't record an error like we do in _mesa_generic_nop() */
+   /* don't record an error like we do in nop_handler() */
+}
+#endif
+
+
+#if !USE_GLAPI_NOP_FEATURES
+static int
+generic_nop(void)
+{
+   GET_CURRENT_CONTEXT(ctx);
+   _mesa_error(ctx, GL_INVALID_OPERATION,
+               "unsupported function called "
+               "(unsupported extension or deprecated function?)");
+   return 0;
+}
+#endif
+
+
+/**
+ * Create a new API dispatch table in which all entries point to the
+ * generic_nop() function.  This will not work on Windows because of
+ * the __stdcall convention which requires the callee to clean up the
+ * call stack.  That's impossible with one generic no-op function.
+ */
+#if !USE_GLAPI_NOP_FEATURES
+static struct _glapi_table *
+new_nop_table(unsigned numEntries)
+{
+   struct _glapi_table *table;
+
+   table = malloc(numEntries * sizeof(_glapi_proc));
+   if (table) {
+      _glapi_proc *entry = (_glapi_proc *) table;
+      unsigned i;
+      for (i = 0; i < numEntries; i++) {
+         entry[i] = (_glapi_proc) generic_nop;
+      }
+   }
+   return table;
 }
 #endif
 
@@ -941,7 +994,11 @@ alloc_dispatch_table(void)
     * Mesa we do this to accommodate different versions of libGL and various
     * DRI drivers.
     */
-   GLint numEntries = MAX2(_glapi_get_dispatch_table_size(), _gloffset_COUNT);
+   int numEntries = MAX2(_glapi_get_dispatch_table_size(), _gloffset_COUNT);
+
+#if !USE_GLAPI_NOP_FEATURES
+   struct _glapi_table *table = new_nop_table(numEntries);
+#else
    struct _glapi_table *table = _glapi_new_nop_table(numEntries);
 
 #if defined(_WIN32)
@@ -967,6 +1024,7 @@ alloc_dispatch_table(void)
 #endif
 
    _glapi_set_nop_handler(nop_handler);
+#endif
 
    return table;
 }