Impala Public Jenkins has submitted this change and it was merged. (
http://gerrit.cloudera.org:8080/10267 )
Change subject: IMPALA-6974: Use CMAKE_POSITION_INDEPENDENT_CODE in backend
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IMPALA-6974: Use CMAKE_POSITION_INDEPENDENT_CODE in backend
Compilation of individual c++ files are only slightly
different between static and shared compilation. First,
CMake adds -D${LIBRARY_NAME}_EXPORTS to each compilation.
Second, CMake sets CMAKE_POSITION_INDEPENDENT_CODE, which
adds an -fPIC/-fPIE flag automatically. The extra define
is not used by our code, so preprocessing results in
identical code. However, we currently add a global -fPIC
to all compilation whether static or shared. This
introduces a second -fPIC flag on shared where static
only has one. This prevents a hit in ccache, even after
preprocessing.
Switching a global -fPIC to CMAKE_POSITION_INDEPENDENT_CODE
eliminates the difference between shared and static
compilation (apart from the added define). This allows
a ccache hit after preprocessing.
There is a slight difference in some of the compile
commands. CMAKE_POSITION_INDEPENDENT_CODE will add
an -fPIC or a -fPIE depending on whether the C++ file
is going to be an executable. For example,
daemon-main.cc gets -fPIE whereas hdfs-scan-node.cc
gets -fPIC. Previously, everything had an -fPIC.
This saves about an hour on all-build-options-ub1604
due to a higher ccache hit rate.
Before:
cache hit (direct) 1523
cache hit (preprocessed) 61
cache miss 12690
After:
cache hit (direct) 1513
cache hit (preprocessed) 5575
cache miss 7186
Change-Id: Id37bb5afa6a9b7909bb4efe1390a67f7d1469544
Reviewed-on: http://gerrit.cloudera.org:8080/10267
Reviewed-by: Dan Hecht <dhe...@cloudera.com>
Reviewed-by: Tim Armstrong <tarmstr...@cloudera.com>
Tested-by: Impala Public Jenkins <impala-public-jenk...@cloudera.com>
---
M be/CMakeLists.txt
1 file changed, 1 insertion(+), 1 deletion(-)
Approvals:
Dan Hecht: Looks good to me, but someone else must approve
Tim Armstrong: Looks good to me, approved
Impala Public Jenkins: Verified
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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: merged
Gerrit-Change-Id: Id37bb5afa6a9b7909bb4efe1390a67f7d1469544
Gerrit-Change-Number: 10267
Gerrit-PatchSet: 6
Gerrit-Owner: Joe McDonnell <joemcdonn...@cloudera.com>
Gerrit-Reviewer: Dan Hecht <dhe...@cloudera.com>
Gerrit-Reviewer: Impala Public Jenkins <impala-public-jenk...@cloudera.com>
Gerrit-Reviewer: Tim Armstrong <tarmstr...@cloudera.com>
