glsl: Switch to disable-by-default for the GLSL shader cache

The shader cache is expected to be developed incrementally over a
fairly long series of commits. For that period of instability, we
require users to opt into the shader cache by setting:

	MESA_GLSL_CACHE_ENABLE=1

In the future, when the shader cache is complete, we can revert this
commit so that the cache will be on by default.

The user can always disable the cache with
MESA_GLSL_CACHE_DISABLE=1. That functionality is not affected by this
commit, (nor will it be affected by the future revert).

Reviewed-by: Eric Anholt <eric@anholt.net>

diff --git a/src/compiler/glsl/tests/cache_test.c b/src/compiler/glsl/tests/cache_test.c
index 0ef05aacb265482ba65d6cbd8f09f010a8bd14ac..8547141051d7d57e5f71c24ebb077afb053cdb67 100644 (file)
--- a/src/compiler/glsl/tests/cache_test.c
+++ b/src/compiler/glsl/tests/cache_test.c
@@ -388,6 +388,11 @@ main(void)
 #ifdef ENABLE_SHADER_CACHE
    int err;
 
+   /* While the shader cache is still experimental, this variable must
+    * be set or the cache does nothing.
+    */
+   setenv("MESA_GLSL_CACHE_ENABLE", "1", 1);
+
    test_disk_cache_create();
 
    test_put_and_get();

diff --git a/src/util/disk_cache.c b/src/util/disk_cache.c
index 6de608c2e4a0ee6e80bfcf773caf29b6f45c5697..551ceebd3b89ee3c7de2f4fcdc791d075fbc1ec0 100644 (file)
--- a/src/util/disk_cache.c
+++ b/src/util/disk_cache.c
@@ -151,6 +151,13 @@ disk_cache_create(void)
    if (getenv("MESA_GLSL_CACHE_DISABLE"))
       goto fail;
 
+   /* As a temporary measure, (while the shader cache is under
+    * development, and known to not be fully functional), also require
+    * the MESA_GLSL_CACHE_ENABLE variable to be set.
+    */
+   if (!getenv("MESA_GLSL_CACHE_ENABLE"))
+      goto fail;
+
    /* Determine path for cache based on the first defined name as follows:
     *
     *   $MESA_GLSL_CACHE_DIR