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Re: PATCH: Add --with-build-config=bootstrap-asan support
On Mon, Nov 19, 2012 at 12:01 AM, Paolo Bonzini <bonzini@gnu.org> wrote:
> Il 19/11/2012 05:35, H.J. Lu ha scritto:
>> On Sun, Nov 18, 2012 at 7:28 AM, Paolo Bonzini <bonzini@gnu.org> wrote:
>>> Il 18/11/2012 00:54, H.J. Lu ha scritto:
>>>> +@if gcc-bootstrap
>>>> +ifneq ($(filter bootstrap-asan,$(BUILD_CONFIG)),)
>>>> +LIBASAN_LIBS=-B$$r/prev-$(TARGET_SUBDIR)/libsanitizer/asan/.libs
>>>> +endif
>>>> +@endif gcc-bootstrap
>>>
>>> Do you need this to be here? POSTSTAGE1_*_EXPORT is only used when
>>> bootstrapping, and they are defined with "=" so the definition could be
>>> placed (or so it seems at first look) in bootstrap-asan.mk.
>>>
>>
>> It turns out to be quite tricky:
>>
>> 1. We can't use -faddress-sanitizer in libcpp due to
>>
>> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55380
>
> Does -faddress-sanitizer add a CPP symbol that lets you work around it?
> If not, it's a bug. If so, please make libcpp revert to the dump
> algorithm if said symbol is defined.
No, it doesn't define a CPP symbol.
>> 2. We can't use -faddress-sanitizer in libiberty since
>> it will make all host binaries depend on libasan.
>> 3. We can't use -faddress-sanitizer in lto-plugin
>> since it will make linker depends on libasan.
>
> These are features, not bugs. You asked for that explicitly. In fact,
> I think that using bootstrap-asan in a combined tree should make all
> host binaries use asan.
That is true. But we have to support separate ld. My patch
will delegate this decision to each tool directory.
>> So basically we can only use -faddress-sanitizer in
>> the gcc directory, which isn't easy to do.
>
> No, there's no need for that.
I'd like to support separate linker.
--
H.J.