Re: [edk2-devel] [PATCH v2 6/7] BaseTools/tools_def CLANG3x ARM AARCH64: force use of C99 standard

["Leif Lindholm" <leif.lindholm@linaro.org>]

On Tue, May 28, 2019 at 08:10:44AM +0200, Ard Biesheuvel wrote:
> On Tue, 28 May 2019 at 02:17, Liming Gao <liming.gao@intel.com> wrote:
> >
> > Ard:
> >   Is there any impact with new option? If no behavior change, I am OK for this patch. Reviewed-by: Liming Gao <liming.gao@intel.com>
> >
> 
> We don't rely on anything provided by the C11 standard, so it should
> not result in a behavior change. I do wonder whether x86 may be
> affected as well, though.

A minor concern would be that GCC defaults to "gnu11" since (after a
cursory search) 5.1, so we could be setting ourselves up for future
clashes. Which is possibly fine, as long as we're aware.

/
    Leif

> Jian, did you try building OpenSSL 1.1.1b for x86 with the CLANG38
> toolchain with a recent version of Clang?
> 
> 
> 
> > >-----Original Message-----
> > >From: Ard Biesheuvel [mailto:ard.biesheuvel@linaro.org]
> > >Sent: Tuesday, May 28, 2019 4:52 AM
> > >To: devel@edk2.groups.io
> > >Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>; Laszlo Ersek
> > ><lersek@redhat.com>; Gao, Liming <liming.gao@intel.com>; Wang, Jian J
> > ><jian.j.wang@intel.com>; Leif Lindholm <leif.lindholm@linaro.org>; Kinney,
> > >Michael D <michael.d.kinney@intel.com>
> > >Subject: [PATCH v2 6/7] BaseTools/tools_def CLANG3x ARM AARCH64: force
> > >use of C99 standard
> > >
> > >When building OpenSSL for ARM or AARCH64 with recent Clang, the following
> > >error may result:
> > >
> > >  In file included
> > >from .../CryptoPkg/Library/BaseCryptLib/Pk/CryptPkcs7VerifyEku.c:18:
> > >  In file included
> > >from .../CryptoPkg/Library/OpensslLib/openssl/crypto/include/internal/x509_
> > >int.h:10:
> > >  In file included
> > >from .../CryptoPkg/Library/OpensslLib/openssl/include/internal/refcount.h:2
> > >1:
> > >  In file included from /usr/lib/llvm-7/lib/clang/7.0.1/include/stdatomic.h:35:
> > >  In file included from /usr/lib/llvm-7/lib/clang/7.0.1/include/stdint.h:61:
> > >  /usr/include/stdint.h:26:10: fatal error: 'bits/libc-header-start.h' file not
> > >found
> > >  #include <bits/libc-header-start.h>
> > >         ^~~~~~~~~~~~~~~~~~~~~~~~~~
> > >  1 error generated.
> > >
> > >This is caused by the fact that the refcount.h header includes compiler
> > >headers that in turn rely on system headers, which we don't support.
> > >
> > >Since the C native atomics are a C11 feature, let's explicitly use the
> > >C99 standard instead to work around this issue.
> > >
> > >Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > >---
> > > BaseTools/Conf/tools_def.template | 8 ++++----
> > > 1 file changed, 4 insertions(+), 4 deletions(-)
> > >
> > >diff --git a/BaseTools/Conf/tools_def.template
> > >b/BaseTools/Conf/tools_def.template
> > >index 26a2cf604f74..7fe6f4406a72 100755
> > >--- a/BaseTools/Conf/tools_def.template
> > >+++ b/BaseTools/Conf/tools_def.template
> > >@@ -2280,8 +2280,8 @@ DEFINE CLANG35_ARM_TARGET        = -target arm-
> > >linux-gnueabi
> > > DEFINE CLANG35_AARCH64_TARGET    = -target aarch64-linux-gnu
> > >
> > > DEFINE CLANG35_WARNING_OVERRIDES = -Wno-parentheses-equality -
> > >Wno-tautological-compare -Wno-tautological-constant-out-of-range-compare
> > >-Wno-empty-body -Wno-unknown-warning-option
> > >-DEFINE CLANG35_ARM_CC_FLAGS      = DEF(GCC_ARM_CC_FLAGS)
> > >DEF(CLANG35_ARM_TARGET) DEF(CLANG35_WARNING_OVERRIDES)
> > >-DEFINE CLANG35_AARCH64_CC_FLAGS  = DEF(GCC_AARCH64_CC_FLAGS)
> > >DEF(CLANG35_AARCH64_TARGET) -mcmodel=small
> > >DEF(CLANG35_WARNING_OVERRIDES)
> > >+DEFINE CLANG35_ARM_CC_FLAGS      = DEF(GCC_ARM_CC_FLAGS)
> > >DEF(CLANG35_ARM_TARGET) DEF(CLANG35_WARNING_OVERRIDES) -
> > >std=c99
> > >+DEFINE CLANG35_AARCH64_CC_FLAGS  = DEF(GCC_AARCH64_CC_FLAGS)
> > >DEF(CLANG35_AARCH64_TARGET) -mcmodel=small
> > >DEF(CLANG35_WARNING_OVERRIDES) -std=c99
> > >
> > > ##################
> > > # CLANG35 ARM definitions
> > >@@ -2430,7 +2430,7 @@ NOOPT_CLANG38_X64_DLINK2_FLAGS     =
> > >DEF(GCC5_X64_DLINK2_FLAGS) -O0
> > > # CLANG38 ARM definitions
> > > ##################
> > > DEFINE CLANG38_ARM_TARGET        = -target arm-linux-gnueabi
> > >-DEFINE CLANG38_ARM_CC_FLAGS      = DEF(GCC_ARM_CC_FLAGS)
> > >DEF(CLANG38_ARM_TARGET) DEF(CLANG38_WARNING_OVERRIDES) -mno-
> > >movt
> > >+DEFINE CLANG38_ARM_CC_FLAGS      = DEF(GCC_ARM_CC_FLAGS)
> > >DEF(CLANG38_ARM_TARGET) DEF(CLANG38_WARNING_OVERRIDES) -mno-
> > >movt -std=c99
> > > DEFINE CLANG38_ARM_DLINK_FLAGS   = DEF(CLANG38_ARM_TARGET)
> > >DEF(GCC_ARM_DLINK_FLAGS)
> > >
> > > *_CLANG38_ARM_PP_FLAGS           = DEF(GCC_PP_FLAGS)
> > >@@ -2474,7 +2474,7 @@ RELEASE_CLANG38_ARM_DLINK_FLAGS  =
> > >DEF(CLANG38_ARM_DLINK_FLAGS) -flto -Wl,-O3 -L
> > > # CLANG38 AARCH64 definitions
> > > ##################
> > > DEFINE CLANG38_AARCH64_TARGET    = -target aarch64-linux-gnu
> > >-DEFINE CLANG38_AARCH64_CC_FLAGS  = DEF(GCC_AARCH64_CC_FLAGS)
> > >DEF(CLANG38_AARCH64_TARGET) -mcmodel=small
> > >DEF(CLANG38_WARNING_OVERRIDES)
> > >+DEFINE CLANG38_AARCH64_CC_FLAGS  = DEF(GCC_AARCH64_CC_FLAGS)
> > >DEF(CLANG38_AARCH64_TARGET) -mcmodel=small
> > >DEF(CLANG38_WARNING_OVERRIDES) -std=c99
> > > DEFINE CLANG38_AARCH64_DLINK_FLAGS  =
> > >DEF(CLANG38_AARCH64_TARGET) DEF(GCC_AARCH64_DLINK_FLAGS) -z
> > >common-page-size=0x1000
> > >
> > > *_CLANG38_AARCH64_PP_FLAGS       = DEF(GCC_PP_FLAGS)
> > >--
> > >2.20.1
> >
> >
> > 
> >