Re: For an armv7 context, /usr/local/llvm1[789]/lib/clang/1[789]/include/arm_bf16.h does not exist: one thing blocking a firefox build via llvm1[78]

Reply: Mark Millard : "Re: For an armv7 context, /usr/local/llvm1[789]/lib/clang/1[789]/include/arm_bf16.h does not exist: one thing blocking a firefox build via llvm1[78]"
In reply to: Mark Millard : "Re: For an armv7 context, /usr/local/llvm1[789]/lib/clang/1[789]/include/arm_bf16.h does not exist: one thing blocking a firefox build via llvm1[78]"
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From: Brooks Davis <brooks_at_freebsd.org>
Date: Tue, 03 Sep 2024 18:12:59 UTC
On Fri, Aug 30, 2024 at 10:05:06PM -0700, Mark Millard wrote:
> On Aug 30, 2024, at 21:26, Mark Millard <marklmi@yahoo.com> wrote:
> 
> > On Aug 30, 2024, at 20:33, Mark Millard <marklmi@yahoo.com> wrote:
> > 
> >> [Subject was retitled.]
> >> 
> >> On Aug 30, 2024, at 16:24, Mark Millard <marklmi@yahoo.com> wrote:
> >> 
> >>> What my test-of-building got was: No <arm_bf16.h> include file found and
> >>> no OFlags::TMPFILE found (OFlags:: was found, TMPFILE in OFlags:: was not):
> >>> 
> >>> In file included from /wrkdirs/usr/ports/www/firefox/work/firefox-129.0.2/mfbt/lz4/xxhash.c:43:
> >>> In file included from /wrkdirs/usr/ports/www/firefox/work/firefox-129.0.2/mfbt/lz4/xxhash.h:3434:
> >>> /usr/local/llvm17/lib/clang/17/include/arm_neon.h:37:10: fatal error: 'arm_bf16.h' file not found
> >>> 37 | #include <arm_bf16.h>
> >>>    |          ^~~~~~~~~~~~
> >>> . . .
> >>> 
> >>> error[E0599]: no associated item named `TMPFILE` found for struct `backend::fs::types::OFlags` in the current scope
> >>> --> /wrkdirs/usr/ports/www/firefox/work/firefox-129.0.2/third_party/rust/rustix/src/backend/libc/fs/syscalls.rs:144:32
> >>>  |
> >>> 144 |       if oflags.contains(OFlags::TMPFILE) && crate::backend::if_glibc_is_less_than_2_25() {
> >>>  |                                  ^^^^^^^ associated item not found in `OFlags`
> >>>  |
> >>> ::: /wrkdirs/usr/ports/www/firefox/work/firefox-129.0.2/third_party/rust/rustix/src/backend/libc/fs/types.rs:203:1
> >>>  |
> >>> 203 | / bitflags! {
> >>> 204 | |     /// `O_*` constants for use with [`openat`].
> >>> 205 | |     ///
> >>> 206 | |     /// [`openat`]: crate::fs::openat
> >>> ...   |
> >>> 333 | |     }
> >>> 334 | | }
> >>>  | |_- associated item `TMPFILE` not found for this struct
> >>>  |
> >>> . . .
> >>>  = note: this error originates in the macro `$crate::__impl_bitflags` which comes from the expansion of the macro `bitflags` (in Nightly builds, run with -Z macro-backtrace for more info)
> >>> 
> >>> . . .
> >>> 
> >>> error[E0599]: no associated item named `TMPFILE` found for struct `backend::fs::types::OFlags` in the current scope
> >>> --> /wrkdirs/usr/ports/www/firefox/work/firefox-129.0.2/third_party/rust/rustix/src/backend/libc/fs/syscalls.rs:207:32
> >>>  |
> >>> 207 |       if oflags.contains(OFlags::TMPFILE) && crate::backend::if_glibc_is_less_than_2_25() {
> >>>  |                                  ^^^^^^^ associated item not found in `OFlags`
> >>>  |
> >>> ::: /wrkdirs/usr/ports/www/firefox/work/firefox-129.0.2/third_party/rust/rustix/src/backend/libc/fs/types.rs:203:1
> >>>  |
> >>> 203 | / bitflags! {
> >>> 204 | |     /// `O_*` constants for use with [`openat`].
> >>> 205 | |     ///
> >>> 206 | |     /// [`openat`]: crate::fs::openat
> >>> ...   |
> >>> 333 | |     }
> >>> 334 | | }
> >>>  | |_- associated item `TMPFILE` not found for this struct
> >>>  |
> >>> . . .
> >>>  = note: this error originates in the macro `$crate::__impl_bitflags` which comes from the expansion of the macro `bitflags` (in Nightly builds, run with -Z macro-backtrace for more info)
> >>> 
> >>> . . .
> >>>  = note: this error originates in the macro `$crate::__impl_bitflags` which comes from the expansion of the macro `bitflags` (in Nightly builds, run with -Z macro-backtrace for more info)
> >>> 
> >>> For more information about this error, try `rustc --explain E0599`.
> >>> error: could not compile `rustix` (lib) due to 2 previous errors
> >>> 
> >>> 
> >>> For reference:
> >>> 
> >>> # uname -apKU
> >>> FreeBSD aarch64-main-pbase 15.0-CURRENT FreeBSD 15.0-CURRENT #8 main-n271819-5cbb98c8259c-dirty: Fri Aug 23 22:06:47 PDT 2024     root@aarch64-main-pbase:/usr/obj/BUILDs/main-CA76-nodbg-clang/usr/main-src/arm64.aarch64/sys/GENERIC-NODBG-CA76 arm64 aarch64 1500023 1500023
> >>> 
> >>> # ~/fbsd-based-on-what-commit.sh -C /usr/ports/
> >>> 87a38a839ab8 (HEAD -> main, freebsd/main, freebsd/HEAD) net-im/dissent: update package description
> >>> Author:     Jan Beich <jbeich@FreeBSD.org>
> >>> Commit:     Jan Beich <jbeich@FreeBSD.org>
> >>> CommitDate: 2024-08-24 18:30:01 +0000
> >>> branch: main
> >>> merge-base: 87a38a839ab83c2def100a0975a7afb29e873cf2
> >>> merge-base: CommitDate: 2024-08-24 18:30:01 +0000
> >>> n674987 (--first-parent --count for merge-base)
> >>> 
> >>> But firefox was updated to use: nss>=3.103:security/nss to match what was
> >>> available.
> >> 
> >> 
> >> Using devel/llvm18 instead got the same.
> >> 
> >> Looking inside even a /usr/local/llvm19/lib/clang/19/include/
> >> also shows the arm_bf16.h file is not present. By contrast,
> >> for an aarch64 context:
> >> 
> >> # file /usr/local/llvm19/lib/clang/19/include/arm_bf16.h
> >> /usr/local/llvm19/lib/clang/19/include/arm_bf16.h: C source, ASCII text
> >> 
> >> Looking quickly at more llvm* shows:
> >> 
> >> # grep -r arm_bf16 /usr/ports/devel/llvm1*/ | more
> >> /usr/ports/devel/llvm11/pkg-plist:%%CLANG%%llvm%%LLVM_SUFFIX%%/lib/clang/%%LLVM_RELEASE%%/include/arm_bf16.h
> >> /usr/ports/devel/llvm12/pkg-plist:%%CLANG%%llvm%%LLVM_SUFFIX%%/lib/clang/%%LLVM_RELEASE%%/include/arm_bf16.h
> >> /usr/ports/devel/llvm13/pkg-plist:%%CLANG%%llvm%%LLVM_SUFFIX%%/lib/clang/%%LLVM_RELEASE%%/include/arm_bf16.h
> >> /usr/ports/devel/llvm14/Makefile:_BE_INCS_ARM=          arm_bf16.h arm_cde.h arm_fp16.h arm_mve.h arm_neon.h arm_sve.h
> >> /usr/ports/devel/llvm15/Makefile:_BE_INCS_ARM=          arm_bf16.h arm_cde.h arm_fp16.h arm_mve.h arm_neon.h arm_sve.h
> >> /usr/ports/devel/llvm16/files/patch-backport-llvm-db49231:    `arm_sve.h` and `arm_bf16.h`, and all those generated files will contain a
> >> /usr/ports/devel/llvm16/files/patch-backport-llvm-db49231:    `arm_bf16.h` immediately before their own typedef:
> >> /usr/ports/devel/llvm16/files/patch-backport-llvm-db49231:        #include <arm_bf16.h>
> >> /usr/ports/devel/llvm16/files/patch-backport-llvm-db49231:    Since `arm_bf16.h` is very likely supposed to be the one true place where
> >> /usr/ports/devel/llvm16/files/patch-backport-llvm-db49231:   OS << "#include <arm_bf16.h>\n";
> >> /usr/ports/devel/llvm16/files/patch-backport-llvm-db49231:   OS << "#include <arm_bf16.h>\n";
> >> /usr/ports/devel/llvm16/Makefile:_BE_INCS_ARM=          arm_bf16.h arm_cde.h arm_fp16.h arm_mve.h arm_neon.h arm_sve.h
> >> /usr/ports/devel/llvm17/Makefile:_BE_INCS_AArch64=      arm_bf16.h arm_sme_draft_spec_subject_to_change.h
> >> /usr/ports/devel/llvm18/Makefile:_BE_INCS_AArch64=      arm_bf16.h
> >> /usr/ports/devel/llvm19/Makefile:_BE_INCS_AArch64=      arm_bf16.h
> >> 
> >> llvm1[456] had _BE_INCS_ARM containing arm_bf16.h (and more).
> >> llvm1[789] do not.
> >> 
> >> I wonder if:
> >> 
> >> https://cgit.freebsd.org/ports/commit/devel/llvm17/Makefile?id=778e212f234a825c5e19612df4be2e8f838cb024
> >> 
> >> doing:
> >> 
> >> -_BE_INCS_ARM= arm_bf16.h arm_cde.h arm_fp16.h arm_mve.h arm_neon.h arm_sve.h
> >> +_BE_INCS_ARM= arm_cde.h arm_fp16.h arm_mve.h arm_neon.h arm_sve.h
> >> 
> >> was correct.  I'll note that in an armv7 context:
> >> 
> >> # find /usr/local/*/gcc14/ -name arm_bf16.h -print
> >> /usr/local/lib/gcc14/gcc/armv7-portbld-freebsd15.0/14.2.0/include/arm_bf16.h
> >> 
> >> suggesting that gcc14 considers the file as not aarch64 specific but
> >> as armv7 compatibile.
> > 
> > I got that wrong! arm vs. aarch64 have different source files with the
> > same name (under different paths):
> > 
> > gcc/gcc/config/arm/arm_bf16.h     has guard test: #ifndef _GCC_ARM_BF16_H
> > gcc/gcc/config/aarch64/arm_bf16.h has guard test: #ifndef _AARCH64_BF16_H_
> > 
> > (More content is different.)
> 
> As for llvm*:
> 
> clang/lib/Basic/Targets/ARM.cpp has:
> 
>   if (HasBFloat16) {
>     Builder.defineMacro("__ARM_FEATURE_BF16", "1");
>     Builder.defineMacro("__ARM_FEATURE_BF16_VECTOR_ARITHMETIC", "1");
>     Builder.defineMacro("__ARM_BF16_FORMAT_ALTERNATIVE", "1");
>   }
> 
> clang/lib/Basic/Targets/AArch64.cpp has:
> 
>   if (HasBFloat16) {
>     Builder.defineMacro("__ARM_FEATURE_BF16", "1");
>     Builder.defineMacro("__ARM_FEATURE_BF16_VECTOR_ARITHMETIC", "1");
>     Builder.defineMacro("__ARM_BF16_FORMAT_ALTERNATIVE", "1");
>   }
> 
> which suggests bf16 support has 32-bit support (even if it is armv8
> 32-bit). Looking for AArch32 state in:
> 
> DDI0487K_a_a-profile_architecture_reference_manual.pdf
> 
> it says (via the AArch32 column of a table):
> 
> BF16 Supported if FEAT_AA32BF16 is implemented.
> 
> Looks to me like the removal of arm_bf16.h for llvm target ARM
> was incorrect.

The commit to the port simply refects changes upstream which made
arm_br16.h aarch64-only.  It was done in a massive commit (a70cf56d20b956)
so may well have been wrong and no one notices because they always build
all the backends.

-- Brooks