[Mesa-dev] [PATCH v2 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).

Cc: Jason Ekstrand <jason at jlekstrand.net>
Cc: mesa-stable at lists.freedesktop.org
Signed-off-by: Emil Velikov <emil.velikov at collabora.com>
---
Strictly speaking v2 _could_ make a difference if one has a machine
powerful enough to have `make' and `make install' each this Makefile
within the same second. That sounds pretty much impossible though :-)

If people prefer we could drop the header all together and provide the
define via the Makefile. It would be a bit unusual (in mesa at least)
but it should work.
---
 src/intel/vulkan/.gitignore   | 1 +
 src/intel/vulkan/Makefile.am  | 9 ++++++++-
 src/intel/vulkan/anv_device.c | 4 ++--
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/intel/vulkan/.gitignore b/src/intel/vulkan/.gitignore
index a496146..ce6f23f 100644
--- a/src/intel/vulkan/.gitignore
+++ b/src/intel/vulkan/.gitignore
@@ -2,3 +2,4 @@
 /anv_entrypoints.c
 /anv_entrypoints.h
 /dev_icd.json
+/anv_timestamp.h
diff --git a/src/intel/vulkan/Makefile.am b/src/intel/vulkan/Makefile.am
index 4d9ff90..5f68f29 100644
--- a/src/intel/vulkan/Makefile.am
+++ b/src/intel/vulkan/Makefile.am
@@ -131,7 +131,14 @@ anv_entrypoints.c : anv_entrypoints_gen.py $(vulkan_include_HEADERS)
 	$(AM_V_GEN) cat $(vulkan_include_HEADERS) |\
 	$(PYTHON2) $(srcdir)/anv_entrypoints_gen.py code > $@
 
-BUILT_SOURCES = $(VULKAN_GENERATED_FILES)
+
+.PHONY: anv_timestamp.h
+
+anv_timestamp.h:
+	@echo "Updating anv_timestamp.h"
+	$(AM_V_GEN) echo "#define ANV_TIMESTAMP `date +%s`" > $@
+
+BUILT_SOURCES = $(VULKAN_GENERATED_FILES) anv_timestamp.h
 CLEANFILES = $(BUILT_SOURCES) dev_icd.json
 EXTRA_DIST = \
 	$(top_srcdir)/include/vulkan/vk_icd.h \
diff --git a/src/intel/vulkan/anv_device.c b/src/intel/vulkan/anv_device.c
index 97300c3..e395b1c 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