[Mesa-dev] [PATCH 2/2] configure: Add machinery for --enable-shader-cache (and --disable-shader-cache)

[Carl Worth]

We don't actually have the code for the shader cache just yet, but
this configure machinery puts everything in place so that the shader
cache can be optionally compiled in.

Specifically, if the user passes no option (neither
--disable-shader-cache, nor --enable-shader-cache), then this feature
will be automatically detected based on the presence of a usable SHA-1
library. If no suitable library can be found, then the shader cache
will be automatically disabled, (and reported in the final output from
configure).

The user can force the shader-cache feature to not be compiled, (even
if a SHA-1 library is detected), by passing
--disable-shader-cache. This will prevent the compiled Mesa libraries
from depending on any library for SHA-1 implementation.

Finally, the user can also force the shader cache on with
--enable-shader-cache. This will cause configure to trigger a fatal
error if no sutiable SHA-1 implementation can be found for the
shader-cache feature.
---
 configure.ac              | 23 ++++++++++++++++++++++-
 src/util/Makefile.sources |  6 +++---
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/configure.ac b/configure.ac
index 9697e9f..0361893 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1026,11 +1026,26 @@ if test "x$with_sha1" = xlibcrypto; then
 	fi
 fi
 AC_MSG_CHECKING([for SHA1 implementation])
-AM_CONDITIONAL([HAVE_SHA1], [ test x$with_sha1 != x ])
 AC_MSG_RESULT([$with_sha1])
 AC_SUBST(SHA1_LIBS)
 AC_SUBST(SHA1_CFLAGS)
 
+# Allow user to configure out the shader-cache feature
+AC_ARG_ENABLE([shader-cache],
+    AS_HELP_STRING([--disable-shader-cache], [Disable binary shader cache]),
+    [enable_shader_cache="$enableval"],
+    [if test "x$with_sha1" != "x"; then
+        enable_shader_cache=yes
+     else
+        enable_shader_cache=no
+     fi])
+if test "x$with_sha1" = "x"; then
+    if test "x$enable_shader_cache" = "xyes"; then
+        AC_MSG_ERROR([Cannot enable shader cache (no SHA-1 implementation found)])
+    fi
+fi
+AM_CONDITIONAL([ENABLE_SHADER_CACHE], [ test x$enable_shader_cache = xyes ])
+
 # Check for libdrm
 PKG_CHECK_MODULES([LIBDRM], [libdrm >= $LIBDRM_REQUIRED],
                   [have_libdrm=yes], [have_libdrm=no])
@@ -2476,6 +2491,12 @@ else
     echo "        Gallium:         no"
 fi
 
+dnl Shader cache
+echo ""
+echo "        Shader cache:    $enable_shader_cache"
+if test "x$enable_shader_cache" = "xyes"; then
+    echo "        With SHA1 from:  $with_sha1"
+fi
 
 dnl Libraries
 echo ""
diff --git a/src/util/Makefile.sources b/src/util/Makefile.sources
index 39f87e4..d76ab13 100644
--- a/src/util/Makefile.sources
+++ b/src/util/Makefile.sources
@@ -1,5 +1,5 @@
-if HAVE_SHA1
-MESA_UTIL_SHA1_FILES := \
+if ENABLE_SHADER_CACHE
+MESA_UTIL_SHADER_CACHE_FILES := \
 	sha1.c \
 	sha1.h
 endif
@@ -11,7 +11,7 @@ MESA_UTIL_FILES :=	\
 	register_allocate.h \
 	rgtc.c \
 	strtod.cpp \
-        $(MESA_UTIL_SHA1_FILES)
+        $(MESA_UTIL_SHADER_CACHE_FILES)
 
 MESA_UTIL_GENERATED_FILES = \
 	format_srgb.c
-- 
2.1.3