| Message ID | f8a2430c-f068-2290-6b95-dc369a9ac385@suse.cz |
|---|---|
| State | New |
| Headers | show |
| Series | [DOCUMENTATION] Document ASLR for Precompiled Headers. | expand |
On Tue, Feb 4, 2020 at 2:45 PM Martin Liška <mliska@suse.cz> wrote: > > Hi. > > The patch is about enhancement of the documentation, where > we do not support ASLR for Precompiled Headers. > > Ready for trunk? I think we support ASLR just fine? > Thanks, > Martin > > gcc/ChangeLog: > > 2020-02-04 Martin Liska <mliska@suse.cz> > > PR c++/92717 > * doc/invoke.texi: Document that one should > not combine ASLR and -fpch. > --- > gcc/doc/invoke.texi | 2 ++ > 1 file changed, 2 insertions(+) > >
On 2/4/20 2:55 PM, Richard Biener wrote: > On Tue, Feb 4, 2020 at 2:45 PM Martin Liška <mliska@suse.cz> wrote: >> >> Hi. >> >> The patch is about enhancement of the documentation, where >> we do not support ASLR for Precompiled Headers. >> >> Ready for trunk? > > I think we support ASLR just fine? There's issue where somebody confirms the opposite: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92717#c8 Martin > >> Thanks, >> Martin >> >> gcc/ChangeLog: >> >> 2020-02-04 Martin Liska <mliska@suse.cz> >> >> PR c++/92717 >> * doc/invoke.texi: Document that one should >> not combine ASLR and -fpch. >> --- >> gcc/doc/invoke.texi | 2 ++ >> 1 file changed, 2 insertions(+) >> >>
On Tue, Feb 04, 2020 at 02:55:31PM +0100, Richard Biener wrote: > On Tue, Feb 4, 2020 at 2:45 PM Martin Liška <mliska@suse.cz> wrote: > > > > Hi. > > > > The patch is about enhancement of the documentation, where > > we do not support ASLR for Precompiled Headers. > > > > Ready for trunk? > > I think we support ASLR just fine? We do support ASLR just fine, just the PCH from it will not be bitwise reproduceable. So the doc patch is misplaced (putting it between sentence talking about options and the list of those options is weird) and should make it clear that ASLR may result in non-reproduceable PCH files. > > gcc/ChangeLog: > > > > 2020-02-04 Martin Liska <mliska@suse.cz> > > > > PR c++/92717 > > * doc/invoke.texi: Document that one should > > not combine ASLR and -fpch. > > --- > > gcc/doc/invoke.texi | 2 ++ > > 1 file changed, 2 insertions(+) > > > > Jakub
On 2/4/20 2:59 PM, Jakub Jelinek wrote: > On Tue, Feb 04, 2020 at 02:55:31PM +0100, Richard Biener wrote: >> On Tue, Feb 4, 2020 at 2:45 PM Martin Liška <mliska@suse.cz> wrote: >>> >>> Hi. >>> >>> The patch is about enhancement of the documentation, where >>> we do not support ASLR for Precompiled Headers. >>> >>> Ready for trunk? >> >> I think we support ASLR just fine? > > We do support ASLR just fine, just the PCH from it will not be bitwise > reproduceable. So the doc patch is misplaced (putting it between sentence > talking about options and the list of those options is weird) and should make > it clear that ASLR may result in non-reproduceable PCH files. You are right. I fixed the placing of the hunk and relaxed the wording. Martin > >>> gcc/ChangeLog: >>> >>> 2020-02-04 Martin Liska <mliska@suse.cz> >>> >>> PR c++/92717 >>> * doc/invoke.texi: Document that one should >>> not combine ASLR and -fpch. >>> --- >>> gcc/doc/invoke.texi | 2 ++ >>> 1 file changed, 2 insertions(+) >>> >>> > > Jakub >
On Tue, Feb 4, 2020 at 4:09 PM Martin Liška <mliska@suse.cz> wrote: > > On 2/4/20 2:59 PM, Jakub Jelinek wrote: > > On Tue, Feb 04, 2020 at 02:55:31PM +0100, Richard Biener wrote: > >> On Tue, Feb 4, 2020 at 2:45 PM Martin Liška <mliska@suse.cz> wrote: > >>> > >>> Hi. > >>> > >>> The patch is about enhancement of the documentation, where > >>> we do not support ASLR for Precompiled Headers. > >>> > >>> Ready for trunk? > >> > >> I think we support ASLR just fine? > > > > We do support ASLR just fine, just the PCH from it will not be bitwise > > reproduceable. So the doc patch is misplaced (putting it between sentence > > talking about options and the list of those options is weird) and should make > > it clear that ASLR may result in non-reproduceable PCH files. > > You are right. I fixed the placing of the hunk and relaxed the wording. I think the wording is still too defensive - "non-reproducible" results suggest the binaries produced are somehow not reproducible (or worse). But it's just the PCH file itself that can differ between builds. So something like "Address space layout randomization (ASLR) can lead to not binary identical PCH files. If you rely on stable PCH file contents disable ASLR when generating PCH files." ? > > Martin > > > > >>> gcc/ChangeLog: > >>> > >>> 2020-02-04 Martin Liska <mliska@suse.cz> > >>> > >>> PR c++/92717 > >>> * doc/invoke.texi: Document that one should > >>> not combine ASLR and -fpch. > >>> --- > >>> gcc/doc/invoke.texi | 2 ++ > >>> 1 file changed, 2 insertions(+) > >>> > >>> > > > > Jakub > > >
On 2/5/20 8:52 AM, Richard Biener wrote: > "Address space layout randomization (ASLR) can lead to not binary identical > PCH files. If you rely on stable PCH file contents disable ASLR when generating > PCH files." > > ? I'm fine with that. Installed as r10-6442-gf4239581925d6a9fba049f8f771e909a7a5e5ce7. Martin
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 4dec0c8326b..eb4b786b405 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -31091,6 +31091,8 @@ for any cases where this rule is relaxed. @item Each of the following options must be the same when building and using the precompiled header: +@item Address space layout randomization (ASLR) is disabled. + @gccoptlist{-fexceptions} @item