sstate: Implement hash equivalence sstate

Converts sstate so that it can use a hash equivalence server to
determine if a task really needs to be rebuilt, or if it can be restored
from a different (equivalent) sstate object.

The unique hashes are cached persistently using persist_data. This has
a number of advantages:
 1) Unique hashes can be cached between invocations of bitbake to
    prevent needing to contact the server every time (which is slow)
 2) The value of each tasks unique hash can easily be synchronized
    between different threads, which will be useful if bitbake is
    updated to do on the fly task re-hashing.

[YOCTO #13030]

(From OE-Core rev: d889acb4f8f06f09cece80fa12661725e6e5f037)

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/meta/conf/bitbake.conf b/meta/conf/bitbake.conf
index 6480062354..e64ce6a6da 100644
--- a/meta/conf/bitbake.conf
+++ b/meta/conf/bitbake.conf
@@ -867,7 +867,9 @@ BB_HASHBASE_WHITELIST ?= "TMPDIR FILE PATH PWD BB_TASKHASH BBPATH BBSERVER DL_DI
     STAMPS_DIR PRSERV_DUMPDIR PRSERV_DUMPFILE PRSERV_LOCKDOWN PARALLEL_MAKE \
     CCACHE_DIR EXTERNAL_TOOLCHAIN CCACHE CCACHE_NOHASHDIR LICENSE_PATH SDKPKGSUFFIX \
     WARN_QA ERROR_QA WORKDIR STAMPCLEAN PKGDATA_DIR BUILD_ARCH SSTATE_PKGARCH \
-    BB_WORKERCONTEXT BB_LIMITEDDEPS extend_recipe_sysroot DEPLOY_DIR"
+    BB_WORKERCONTEXT BB_LIMITEDDEPS BB_UNIHASH extend_recipe_sysroot DEPLOY_DIR \
+    SSTATE_HASHEQUIV_METHOD SSTATE_HASHEQUIV_SERVER SSTATE_HASHEQUIV_REPORT_TASKDATA \
+    SSTATE_HASHEQUIV_OWNER"
 BB_HASHCONFIG_WHITELIST ?= "${BB_HASHBASE_WHITELIST} DATE TIME SSH_AGENT_PID \
     SSH_AUTH_SOCK PSEUDO_BUILD BB_ENV_EXTRAWHITE DISABLE_SANITY_CHECKS \
     PARALLEL_MAKE BB_NUMBER_THREADS BB_ORIGENV BB_INVALIDCONF BBINCLUDED \