Laszlo: I will verify your option (a) and (b). The problem is described in https://bugzilla.tianocore.org/show_bug.cgi?id=2024. I know there are some discussion in Jordan patch for PeiCore change. Before the conclusion for Jordan change is made, I expect to find the alternate option to resolve CLANG9 tool chain issue first.
Thanks Liming > -----Original Message----- > From: Laszlo Ersek <ler...@redhat.com> > Sent: Tuesday, October 1, 2019 5:10 AM > To: devel@edk2.groups.io; Gao, Liming <liming....@intel.com>; Justen, Jordan > L <jordan.l.jus...@intel.com> > Subject: Re: [edk2-devel] [Patch 12/12] OvmfPkg SecMain: Add build option > "-fno-omit-frame-pointer" for CLANG9 X64 > > + Jordan > > On 09/27/19 09:46, Liming Gao wrote: > > BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2024 > > > > Signed-off-by: Liming Gao <liming....@intel.com> > > --- > > OvmfPkg/Sec/SecMain.inf | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/OvmfPkg/Sec/SecMain.inf b/OvmfPkg/Sec/SecMain.inf > > index 63ba4cb555..cd765cac25 100644 > > --- a/OvmfPkg/Sec/SecMain.inf > > +++ b/OvmfPkg/Sec/SecMain.inf > > @@ -69,3 +69,7 @@ > > > > [FeaturePcd] > > gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire > > + > > +[BuildOptions] > > + # CLANG9 X64 requires it. > > + GCC:*_CLANG9_X64_CC_FLAGS = -fno-omit-frame-pointer > > > > I disagree with this patch for two reasons. > > First, the comment "CLANG9 X64 requires it" is quite lacking. It does > nothing to explain the issue; it doesn't even provide a pointer in the > code comment (only in the code message). > > Second, Jordan suggested an alternative approach at the end of > <https://bugzilla.tianocore.org/show_bug.cgi?id=2024#c3>, which I prefer > to the one seen above. Can we please try that with CLANG9 too? > > > ... Oh wait I see there are new comments in BZ#2024. > > Apparently, > > #pragma GCC optimize ("no-omit-frame-pointer") > > does not work with CLANG9. > > That's not a problem: we still have two options that are superior to the > present patch, and should be tested. > > (a) Does Jordan's series linked below fix the problem with CLANG9? > > [edk2-devel] [PATCH v2 0/6] Fix PEI Core issue during TemporaryRamMigration > http://mid.mail-archive.com/20190410084000.19660-1-jordan.l.justen@intel.com > https://edk2.groups.io/g/devel/message/38785 > > (b) Jordan's full #pragma suggestion was: > > #ifdef __GNUC__ > #pragma GCC push_options > #pragma GCC optimize ("no-omit-frame-pointer") > #else > #pragma optimize ("y", off) > #endif > > If the '#pragme GCC' branch doesn't help, can we customize the *other* > branch for CLANG9? > > For example, in patch#4, we rely on defined(__clang__). Therefore, can > we try the following: > > #ifdef __GNUC__ > #pragma GCC push_options > #pragma GCC optimize ("no-omit-frame-pointer") > #elif defined(__clang__) > #pragma clang optimize off <----- NOTE THIS > <http://clang.llvm.org/docs/LanguageExtensions.html> > #else > #pragma optimize ("y", off) > #endif > > In summary, the fact that CLANG9 breaks is just a symptom; it shows that > the PEI Core issue fixed by Jordan is real. We should go for the real > fix (a). > > Alternatively, use a clang-specific optimization override, as tightly as > possible; (b) might work. > > -*- > > In fact I think this is the perfect time to fix the PEI Core issue: we > now have a feature request that depends on fixing the bug in the PEI > Core. We should fix technical debt in edk2 at least *sometimes*. If we > are not willing to fix technical debt in edk2 for the sake of new > features, we will *never* fix technical debt. > > (Well, to be technically correct, we also fix technical debt when it > turns into security issues. Yay!) > > Please test this series with the present patch removed, and Jordan's v2 > series (linked above) applied. > > Thanks > Laszlo -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#48585): https://edk2.groups.io/g/devel/message/48585 Mute This Topic: https://groups.io/mt/34309065/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
