mesa: In helpers, only check driver capability for meta

Make API context and version checks done by the helper functions pass
unconditionally while meta is in progress. This transparently makes
extension checks solely dependent on struct gl_extensions while in meta.

v2: Use an 8-bit data type instead of a GLuint

Signed-off-by: Nanley Chery <nanley.g.chery@intel.com>
Reviewed-by: Chad Versace <chad.versace@intel.com>

src/mesa/drivers/common/meta.c

@@ -449,6 +449,16 @@ _mesa_meta_begin(struct gl_context *ctx, GLbitfield state)
    save->API = ctx->API;
    ctx->API = API_OPENGL_COMPAT;
 
+   /* Mesa's extension helper functions use the current context's API to look up
+    * the version required by an extension as a step in determining whether or
+    * not it has been advertised. Since meta aims to only be restricted by the
+    * driver capability (and not by whether or not an extension has been
+    * advertised), set the helper functions' Version variable to a value that
+    * will make the checks on the context API and version unconditionally pass.
+    */
+   save->ExtensionsVersion = ctx->Extensions.Version;
+   ctx->Extensions.Version = ~0;
+
    /* Pausing transform feedback needs to be done early, or else we won't be
     * able to change other state.
     */
@@ -1222,6 +1232,7 @@ _mesa_meta_end(struct gl_context *ctx)
    ctx->Meta->SaveStackDepth--;
 
    ctx->API = save->API;
+   ctx->Extensions.Version = save->ExtensionsVersion;
 }
 
 

src/mesa/drivers/common/meta.h

@@ -72,6 +72,7 @@ struct save_state
 
    /* Always saved/restored with meta. */
    gl_api API;
+   uint8_t ExtensionsVersion;
 
    /** MESA_META_CLEAR (and others?) */
    struct gl_query_object *CurrentOcclusionObject;

src/mesa/main/extensions.h

@@ -91,7 +91,7 @@ enum {
 static inline bool \
 _mesa_has_##name_str(const struct gl_context *ctx) \
 { \
-   return ctx->Extensions.driver_cap && (ctx->Version >= \
+   return ctx->Extensions.driver_cap && (ctx->Extensions.Version >= \
           _mesa_extension_table[MESA_EXTENSION_##name_str].version[ctx->API]); \
 }
 #include "extensions_table.h"

src/mesa/main/mtypes.h

@@ -3820,6 +3820,12 @@ struct gl_extensions
    const GLubyte *String;
    /** Number of supported extensions */
    GLuint Count;
+   /**
+    * The context version which extension helper functions compare against.
+    * By default, the value is equal to ctx->Version. This changes to ~0
+    * while meta is in progress.
+    */
+   GLubyte Version;
 };
 
 

src/mesa/main/version.c

@@ -524,6 +524,7 @@ _mesa_compute_version(struct gl_context *ctx)
       return;
 
    ctx->Version = _mesa_get_version(&ctx->Extensions, &ctx->Const, ctx->API);
+   ctx->Extensions.Version = ctx->Version;
 
    /* Make sure that the GLSL version lines up with the GL version. In some
     * cases it can be too high, e.g. if an extension is missing.