[cfe-dev] -fcheck-new not supported by LLVM/clang
li.beinan at gmail.com
Tue Nov 6 13:22:44 PST 2012
With Xcode4.5, llvm/clang:
Apple clang version 4.1 (tags/Apple/clang-421.11.66) (based on LLVM 3.1svn)
Thread model: posix
we use -fcheck-new in our compiler settings which has been triggering this
clang: warning: argument unused during compilation: '-fcheck-new'
We wonder if this gcc setting is not supported by clang.
gcc spec seems to say that without this the only mechanism against heap
allocation returning null pointers
is through exceptions. However, we disabled exceptions for performance
requirements. So this setting
is important to us.
Currently we have to use -Qunused-arguments to suppress the warnings, but
the real question is whether or not it is safe to work without -fcheck-new
if it's not supported by clang.
>From web search, we also found the following links which implies that it
could be a bug in LLVM/clang:
If -fcheck-new is an important feature for you (and not a
workaround for an old gcc
problem), please feel free to file a bug at http://llvm.org/bugs/
- Except for the -fcheck-new option, Clang seems to understand all the
other compiler options used during the HotSpot build process. For
-fcheck-new a warning is issued advertising that the option will be
ignored. So I just removed it frommake/linux/makefiles/clang.make. I
have also removed obvious workarounds for some older GCC versions in the
new Clang files which were derived from their corresponding GCC
There was a longer discussion around the fix for the CHECK macros
about one and a half years ago. I started a patch that time but than
somehow forgot about it. Now with the new compiler (and the old
warnings) I remembered about it. I hope to get it done this time and
to send it out for review soon. Thank you for the offer to take care
Anybody has any comments?
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