On 2015-04-20 09:02, Erik Joelsson wrote:
Looks good to me.
Thanks Erik.
Unfortunately, I never got round to pushing this. In the meantime, the
codebase evolved, and I had to add a couple of more disabled warnings. I
also modified the help text on a failed build slightly.
Here's the updated webrev:
http://cr.openjdk.java.net/~ihse/JDK-8074859-warnings-as-errors/webrev.01
/Magnus
/Erik
On 2015-04-17 14:52, Magnus Ihse Bursie wrote:
With JDK-8074096, the number of warnings in the product was reduced
to a minimum. This enables the next step, which is turning on the
respective compiler flags that turns warnings into errors. In the
long run, this is the only way to keep the warnings from creeping back.
Even with JDK-8074096, the product does not build 100% warning free.
This is due to some warnings that cannot be disabled, or (in one
case) where C and C++ code is mixed, and warnings for both languages
cannot be used. A system similar to the one introduced in JDK-8074096
is therefore needed, in which individual libraries can be exempted
from this flag, until such warnings are fixed. A library can thus
disable warnings as errors with WARNINGS_AS_ERRORS := false, or
(better) use a toolchain-specific version, e.g WARNINGS_AS_ERRORS_gcc
:= false. This is intended as a temporary measure, though. The
long-term solution is reasonably to fix the warnings and remove that
argument.
Also, different versions of compilers can generate a different set of
warnings. It is therefore necessary to be able to turn off this
globally. Therefor a new flag for configure is introduced:
--disable-warnings-as-errors.
While the code compiles without errors on the build systems used
internally at Oracle, this might not be the case on other
combinations of operating system versions and toolchain versions. To
facilitate for unexpecting developers, a help message is added if the
build fails, that suggests using --disable-warnings-as-errors. This
solution was chosen as a compromise between the "hard core" solution
of turning on warnings as errors by default for anyone, and the
cowar... erm, conservative solution of checking if the compiler
versions exactly match what's used inside Oracle (and therefore
regularly tested), and only turn it on in that case.
Similarly to JDK-8074096, I intend to file follow-up bugs for each
individual library that got a WARNINGS_AS_ERRORS_* := false.
Bug: https://bugs.openjdk.java.net/browse/JDK-8074859
WebRev for top:
http://cr.openjdk.java.net/~ihse/JDK-8074859-warnings-as-errors-top/webrev.01
WebRev for jdk:
http://cr.openjdk.java.net/~ihse/JDK-8074859-warnings-as-errors-jdk/webrev.01
Some comments:
* I needed to add a few more DISABLED_WARNINGS. For windows, this is
most likely due to the recent compiler change. For other libraries,
I'm not sure, but it might well be the result of recent changes that
has introduced new warnings. If so, it highlights the need of this
patch to keep the build warning free.
* For a few libraries and toolchains, there is *both*
WARNINGS_AS_ERRORS := false and a DISABLED_WARNINGS list. This is the
case if not all warnings are possible to disable.
* I have removed some incorrect uses of SHARED_LIBRARY_FLAGS. This is
included in our JDK LDFLAGS, so it should not be set separately, and
definitely not as CFLAGS. (This caused compiler warnings, which now
turned into errors.) However, a more suitable long-term solution is
probably to move the knowledge of how to create shared libraries more
specifically into SetupNativeCompilation, and not set it as part of
the JDK flags.
/Magnus
