RFR: JDK-8160926: FLAGS_COMPILER_CHECK_ARGUMENTS doesn't handle cross-compilation

Magnus Ihse Bursie magnus.ihse.bursie at oracle.com
Tue Feb 5 09:12:50 UTC 2019


On 2019-02-05 01:36, Erik Joelsson wrote:
> Please review this fix for configure flags checking. The macros for 
> checking compiler capabilities were not able to handle cross 
> compilation very well. With this fix, they accept an optional PREFIX 
> argument, instructing them to check the compiler with the given prefix 
> (which is either empty or BUILD_). Using this, I have moved all calls 
> to the macros into BUILD/TARGET specific macro bodies so that we 
> correctly check both the build and target compilers for valid flags.
>
> I have verified by running cross compilation configurations of 
> linux-aarch64 using both the same and different versions of GCC for 
> build and target, and compared the output in both configure.log and 
> the spec files. I've also run tier1 (equivalent to submission forest) 
> and a  COMPARE_BUILD run on Oracle's main platforms as well.
>
> The change unfortunately required adding another prefix type format 
> since our compiler/tool variables use <empty>/BUILD_ as prefix and the 
> existing formats were TARGET_/BUILD_ and <empty>/OPENJDK_TARGET_. I 
> think we could benefit greatly from unifying these.
>
> I've also touched some white space nearby my changes as well as fixed 
> a trivial error message about "linker" not being found by quoting the 
> LINKER_NAME assignment in toolchain.m4.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8160926
>
> Webrev: http://cr.openjdk.java.net/~erikj/8160926/webrev.01
Looks good. Thanks for finally getting this fixed.

A related problem, that perhaps should be fixed at the same time, is 
that we need to add -Werror to provoke an actual warning message that 
fails. This has been done manually in some (but not all) cases where we 
call FLAGS_COMPILER_CHECK_ARGUMENTS. It might depend on version of gcc, 
or what kind of options we are testing -- I don't remember the detail. 
But I think it would be safe, and prudent, to let 
FLAGS_COMPILER_CHECK_ARGUMENTS automatically add 
$CFLAGS_WARNINGS_ARE_ERRORS to the flag tested. (Assuming that the 
definition of CFLAGS_WARNINGS_ARE_ERRORS is available at the time of 
first call to FLAGS_COMPILER_CHECK_ARGUMENTS, but I think it is, or 
rather, should be.)

/Magnus


> /Erik
>



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