Hello Matthias,
It's our experience that GCC ignores unknown warning tags, so we regard
it as safe to disable warnings only present in later versions of GCC. If
another error is triggered, it will however print a message like you
describe for any unknown tags. This is what happened in the issue
Aleksey linked and I suspect is also happening for you.
/Erik
On 2018-10-31 08:40, Baesken, Matthias wrote:
Hello, I noticed that we currently set flags for gcc to disable warnings.
See
https://hg.openjdk.java.net/jdk/jdk/file/896e80158d35/make/hotspot/lib/CompileJvm.gmk
DISABLED_WARNINGS_gcc := extra parentheses comment unknown-pragmas address \
delete-non-virtual-dtor char-subscripts array-bounds int-in-bool-context \
ignored-qualifiers missing-field-initializers implicit-fallthrough \
empty-body strict-overflow sequence-point maybe-uninitialized \
misleading-indentation
However int-in-bool-context ( -Wnoint-in-bool-context ) seems to be
available only in gcc 7 + .
Example call with gcc 6 leads to a warning :
/gcc-6/bin/gcc sizeof.c -Wall -Wextra -Wno-int-in-bool-context -o
sizeof
sizeof.c: At top level:
cc1: warning: unrecognized command line option '-Wno-int-in-bool-context'
Should we force all users to gcc 7 and higher (otherwise we could maybe
check CC_VERSION_NUMBER in the makefile) ?
Before we internally switched our OpenJDK builds from gcc 4.8 to gcc 7
we had a patch in our build-queue that disabled the
-Wnoint-in-bool-context .
Best regards, Matthias
