mesa: Generate a helper function for each extension

Generate functions which determine if an extension is supported in the
current context. Initially, enums were going to be explicitly used with
_mesa_extension_supported(). The idea to embed the function and enums
into generated helper functions was suggested by Kristian Høgsberg.

For performance, the function body no longer uses
_mesa_extension_supported() and, as suggested by Chad Versace, the
functions are also declared static inline.

v2: Place function qualifiers on separate line (Chad)
v3: Move function curly brace to new line (Chad)

Signed-off-by: Nanley Chery <[email protected]>
Reviewed-by: Chad Versace <[email protected]>

1 files changed, 42 insertions, 0 deletions

diff --git a/src/mesa/main/extensions.h b/src/mesa/main/extensions.h
index 595512a5d5c..6092eca36e7 100644
--- a/src/mesa/main/extensions.h
+++ b/src/mesa/main/extensions.h
@@ -55,6 +55,48 @@ _mesa_get_extension_count(struct gl_context *ctx);
 extern const GLubyte *
 _mesa_get_enabled_extension(struct gl_context *ctx, GLuint index);
 
+
+/**
+ * \brief An element of the \c extension_table.
+ */
+struct extension {
+   /** Name of extension, such as "GL_ARB_depth_clamp". */
+   const char *name;
+
+   /** Offset (in bytes) of the corresponding member in struct gl_extensions. */
+   size_t offset;
+
+   /** Minimum version the extension requires for the given API
+    * (see gl_api defined in mtypes.h). The value is equal to:
+    * 10 * major_version + minor_version
+    */
+   uint8_t version[API_OPENGL_LAST + 1];
+
+   /** Year the extension was proposed or approved.  Used to sort the 
+    * extension string chronologically. */
+   uint16_t year;
+} extern const extension_table[];
+
+
+/* Generate enums for the functions below */
+enum {
+#define EXT(name_str, ...) MESA_EXTENSION_##name_str,
+#include "extensions_table.h"
+#undef EXT
+};
+
+
+/** Checks if the context suports a user-facing extension */
+#define EXT(name_str, driver_cap, ...) \
+static inline bool \
+_mesa_has_##name_str(const struct gl_context *ctx) \
+{ \
+   return ctx->Extensions.driver_cap && (ctx->Version >= \
+          extension_table[MESA_EXTENSION_##name_str].version[ctx->API]); \
+}
+#include "extensions_table.h"
+#undef EXT
+
 extern struct gl_extensions _mesa_extension_override_enables;
 extern struct gl_extensions _mesa_extension_override_disables;