Mesa (master): glsl/linker: Allow mixing of desktop GLSL versions.

[Paul Berry]

Module: Mesa
Branch: master
Commit: 672fab0b1bdffbbdf689f8494c798f868d4d84a4
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=672fab0b1bdffbbdf689f8494c798f868d4d84a4

Author: Paul Berry <stereotype441 at gmail.com>
Date:   Sun Oct 13 18:01:11 2013 -0700

glsl/linker: Allow mixing of desktop GLSL versions.

Previously, Mesa followed the linkage rules outlined in the GLSL
1.20-1.40 specs, which (collectively) said that GLSL versions 1.10 and
1.20 could be linked together, but no other versions could be linked.

In GLSL 4.30, the linkage rules were relaxed so that any two desktop
GLSL versions can be linked together.  This change was made because it
reflected the behaviour of nearly all existing implementations (see
Khronos bug 8463).  Mesa was one of the few (perhaps the only)
exceptions to prohibit cross-linking of some GLSL versions.

Since the GLSL linkage rules were deliberately relaxed in order to
match the behaviour of existing implementations, it seems appropriate
to relax the rules in Mesa too (even though Mesa doesn't support GLSL
4.30 yet).

Note that linking ES and desktop shaders is still prohibited, as is
linking ES shaders having different GLSL versions.

Fixes piglit tests "shaders/version-mixing {interstage,intrastage}".

Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
Reviewed-by: Eric Anholt <eric at anholt.net>

---

 src/glsl/linker.cpp |   10 +++-------
 1 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index 9095a40..0a949b4 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -2057,14 +2057,10 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
       }
    }
 
-   /* Previous to GLSL version 1.30, different compilation units could mix and
-    * match shading language versions.  With GLSL 1.30 and later, the versions
-    * of all shaders must match.
-    *
-    * GLSL ES has never allowed mixing of shading language versions.
+   /* In desktop GLSL, different shader versions may be linked together.  In
+    * GLSL ES, all shader versions must be the same.
     */
-   if ((is_es_prog || max_version >= 130)
-       && min_version != max_version) {
+   if (is_es_prog && min_version != max_version) {
       linker_error(prog, "all shaders must use same shading "
 		   "language version\n");
       goto done;