[Mesa-dev] [PATCHv5 2/4] anv: use cache uuid based on the build timestamp.

[Emil Velikov]

From: Emil Velikov <emil.velikov at collabora.com>

Do not rely on the git sha1:
 - its current truncated form makes it less unique
 - it does not attribute for local (Vulkand or otherwise) changes

Use a timestamp produced at the time of build. It's perfectly unique,
unless someone explicitly thinkers with their system clock. Even then
chances of producing the exact same one are very small, if not zero.

v2: Remove .tmp rule. Its not needed since we want for the header to be
regenerated on each time we call make (Eric).

v3:
 - Honour SOURCE_DATE_EPOCH, to make the build reproducible (Michel)
 - Replace the generated header with a define, to prevent needless
builds on consecutive `make' and/or `make install' calls. (Dave)

v4:
 - Keep the timestamp generation at make time. (Jason)

v5:
 - Ensure that file is regenerated on incremental builds.

Cc: mesa-stable at lists.freedesktop.org
Signed-off-by: Emil Velikov <emil.velikov at collabora.com>
---
 configure.ac                  |  2 ++
 src/intel/vulkan/Makefile.am  | 10 +++++++++-
 src/intel/vulkan/anv_device.c |  4 ++--
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/configure.ac b/configure.ac
index 8321e8e..3d32c53 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2620,6 +2620,8 @@ AC_SUBST([XA_MINOR], $XA_MINOR)
 AC_SUBST([XA_TINY], $XA_TINY)
 AC_SUBST([XA_VERSION], "$XA_MAJOR.$XA_MINOR.$XA_TINY")
 
+AC_SUBST([TIMESTAMP_CMD], '`test $(SOURCE_DATE_EPOCH) && echo $(SOURCE_DATE_EPOCH) || date +%s`')
+
 AC_ARG_ENABLE(valgrind,
               [AS_HELP_STRING([--enable-valgrind],
                              [Build mesa with valgrind support (default: auto)])],
diff --git a/src/intel/vulkan/Makefile.am b/src/intel/vulkan/Makefile.am
index 4d9ff90..3f49020 100644
--- a/src/intel/vulkan/Makefile.am
+++ b/src/intel/vulkan/Makefile.am
@@ -131,8 +131,16 @@ anv_entrypoints.c : anv_entrypoints_gen.py $(vulkan_include_HEADERS)
 	$(AM_V_GEN) cat $(vulkan_include_HEADERS) |\
 	$(PYTHON2) $(srcdir)/anv_entrypoints_gen.py code > $@
 
+.PHONY: anv_timestamp.h
+
+anv_timestamp.h:
+	@echo "Updating anv_timestamp.h"
+	$(AM_V_GEN) echo "#define ANV_TIMESTAMP \"$(TIMESTAMP_CMD)\"" > $@
+
+anv_device.$(OBJEXT): anv_timestamp.h
+
 BUILT_SOURCES = $(VULKAN_GENERATED_FILES)
-CLEANFILES = $(BUILT_SOURCES) dev_icd.json
+CLEANFILES = $(BUILT_SOURCES) dev_icd.json anv_timestamp.h
 EXTRA_DIST = \
 	$(top_srcdir)/include/vulkan/vk_icd.h \
 	anv_entrypoints_gen.py \
diff --git a/src/intel/vulkan/anv_device.c b/src/intel/vulkan/anv_device.c
index ea8e875..dd941b6 100644
--- a/src/intel/vulkan/anv_device.c
+++ b/src/intel/vulkan/anv_device.c
@@ -28,7 +28,7 @@
 #include <fcntl.h>
 
 #include "anv_private.h"
-#include "git_sha1.h"
+#include "anv_timestamp.h"
 #include "util/strtod.h"
 #include "util/debug.h"
 
@@ -426,7 +426,7 @@ void
 anv_device_get_cache_uuid(void *uuid)
 {
    memset(uuid, 0, VK_UUID_SIZE);
-   snprintf(uuid, VK_UUID_SIZE, "anv-%s", MESA_GIT_SHA1 + 4);
+   snprintf(uuid, VK_UUID_SIZE, "anv-%s", ANV_TIMESTAMP);
 }
 
 void anv_GetPhysicalDeviceProperties(
-- 
2.8.2