[ISSUE] darktable-3.0.x: build fails for aarch64* with openmp

[ISSUE] darktable-3.0.x: build fails for aarch64* with openmp

[lemmi]

[-- Attachment #1: Type: text/plain, Size: 1384 bytes --]

New issue by lemmi on void-packages repository

https://github.com/void-linux/void-packages/issues/21105

Description:
Opening this issue to document the error when cross compiling darktable for aarch64:
```
/builddir/darktable-3.0.1/src/common/bilateral.c:332:6: warning: GCC does not currently support mixed size types for 'simd' functions
  332 | void dt_bilateral_slice_to_output(const dt_bilateral_t *const b, const float *const in, float *out,
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/builddir/darktable-3.0.1/src/common/bilateral.c:276:6: warning: GCC does not currently support mixed size types for 'simd' functions
  276 | void dt_bilateral_slice(const dt_bilateral_t *const b, const float *const in, float *out, const float detail)
      |      ^~~~~~~~~~~~~~~~~~
/tmp/cc0eANtK.s: Assembler messages:
/tmp/cc0eANtK.s:3724: Error: unknown pseudo-op: `.variant_pcs'
/tmp/cc0eANtK.s:3861: Error: unknown pseudo-op: `.variant_pcs'
/tmp/cc0eANtK.s:3986: Error: unknown pseudo-op: `.variant_pcs'
/tmp/cc0eANtK.s:4164: Error: unknown pseudo-op: `.variant_pcs'
make[2]: *** [src/CMakeFiles/lib_darktable.dir/build.make:136: src/CMakeFiles/lib_darktable.dir/common/bilateral.c.o] Error 1
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [CMakeFiles/Makefile2:1829: src/CMakeFiles/lib_darktable.dir/all] Error 2
make: *** [Makefile:172: all] Error 2
```

Re: darktable-3.0.x: build fails for aarch64* with openmp

[Sturmflut]

[-- Attachment #1: Type: text/plain, Size: 2522 bytes --]

New comment by Sturmflut on void-packages repository

https://github.com/void-linux/void-packages/issues/21105#issuecomment-755413178

Comment:
I just ran into the same problem when building for Fujitsu A64FX with GCC 9.2.1 on CentOS 8.2. This is the full compiler all:

`/opt/rh/gcc-toolset-9/root/usr/bin/cc -DDT_HAVE_SIGNAL_TRACE -DGDK_DISABLE_DEPRECATED -DGDK_VERSION_MIN_REQUIRED=GDK_VERSION_3_22 -DGLIB_VERSION_MAX_ALLOWED=GLIB_VERSION_MIN_REQUIRED -DGLIB_VERSION_MIN_REQUIRED=GLIB_VERSION_2_40 -DGTK_DISABLE_DEPRECATED -DGTK_DISABLE_SINGLE_INCLUDES -DHAVE_CONFIG_H -DHAVE_GAME -DHAVE_ICU -DHAVE_KWALLET -DHAVE_LENSFUN -DHAVE_OPENCL -DHAVE_SQLITE_324_OR_NEWER -DSQLITE_CORE -DSQLITE_ENABLE_ICU -D_XOPEN_SOURCE=700 -D__GDK_KEYSYMS_COMPAT_H__ -Dlib_darktable_EXPORTS -I/home/scc/mr2515/darktable/build/bin -I/home/scc/mr2515/darktable/src -isystem /home/scc/mr2515/darktable/src/external -isystem /home/scc/mr2515/darktable/src/external/OpenCL -I/home/scc/mr2515/darktable/build/lib64/darktable/rawspeed/src -isystem /home/scc/mr2515/darktable/src/external/rawspeed/src/external -I/home/scc/mr2515/darktable/src/external/rawspeed/src/librawspeed -I/home/scc/mr2515/darktable/src/external/whereami/src -isystem /usr/include/glib-2.0 -isystem /usr/lib64/glib-2.0/include -isystem /usr/include/gtk-3.0 -isystem /usr/include/pango-1.0 -isystem /usr/include/fribidi -isystem /usr/include/cairo -isystem /usr/include/pixman-1 -isystem /usr/include/freetype2 -isystem /usr/include/libpng16 -isystem /usr/include/uuid -isystem /usr/include/harfbuzz -isystem /usr/include/gdk-pixbuf-2.0 -isystem /usr/include/gio-unix-2.0 -isystem /usr/include/atk-1.0 -isystem /usr/include/at-spi2-atk/2.0 -isystem /usr/include/at-spi-2.0 -isystem /usr/include/dbus-1.0 -isystem /usr/lib64/dbus-1.0/include -isystem /usr/include/libxml2 -isystem /home/scc/mr2515/local/include -isystem /usr/include/librsvg-2.0 -isystem /usr/include/json-glib-1.0  -Wall -Wformat -Wformat-security -Wshadow -Wtype-limits -Wvla -Wold-style-declaration -Wno-unknown-pragmas -Wno-error=varargs -Wno-format-truncation -Wno-error=address-of-packed-member -std=c99 -fopenmp -march=native  -g -O2 -g -DNDEBUG -O2 -fPIC   -Werror -Wfatal-errors -o CMakeFiles/lib_darktable.dir/common/bilateral.c.o   -c /home/scc/mr2515/darktable/src/common/bilateral.c`

Looks like an actual compiler limitation on ARMv8A. The other compilers on the system are Cray 10 and Clang 10, but both don't pass the "supported platform" test in the CMakeFile.

I'll try to build GCC 10.

Re: darktable-3.0.x: build fails for aarch64* with openmp

[lemmi]

[-- Attachment #1: Type: text/plain, Size: 328 bytes --]

New comment by lemmi on void-packages repository

https://github.com/void-linux/void-packages/issues/21105#issuecomment-755870556

Comment:
Thanks for reporting. At the moment we turned openmp off, which is kind of a shame, since we now seem to get affordable multicore machines with aarch64.
Which darktable version is this? 

Re: darktable-3.0.x: build fails for aarch64* with openmp

[github-actions]

[-- Attachment #1: Type: text/plain, Size: 293 bytes --]

New comment by github-actions[bot] on void-packages repository

https://github.com/void-linux/void-packages/issues/21105#issuecomment-1100506602

Comment:
Issues become stale 90 days after last activity and are closed 14 days after that.  If this issue is still relevant bump it or assign it.

Re: [ISSUE] [CLOSED] darktable-3.0.x: build fails for aarch64* with openmp

[github-actions]

[-- Attachment #1: Type: text/plain, Size: 1387 bytes --]

Closed issue by lemmi on void-packages repository

https://github.com/void-linux/void-packages/issues/21105

Description:
Opening this issue to document the error when cross compiling darktable for aarch64:
```
/builddir/darktable-3.0.1/src/common/bilateral.c:332:6: warning: GCC does not currently support mixed size types for 'simd' functions
  332 | void dt_bilateral_slice_to_output(const dt_bilateral_t *const b, const float *const in, float *out,
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/builddir/darktable-3.0.1/src/common/bilateral.c:276:6: warning: GCC does not currently support mixed size types for 'simd' functions
  276 | void dt_bilateral_slice(const dt_bilateral_t *const b, const float *const in, float *out, const float detail)
      |      ^~~~~~~~~~~~~~~~~~
/tmp/cc0eANtK.s: Assembler messages:
/tmp/cc0eANtK.s:3724: Error: unknown pseudo-op: `.variant_pcs'
/tmp/cc0eANtK.s:3861: Error: unknown pseudo-op: `.variant_pcs'
/tmp/cc0eANtK.s:3986: Error: unknown pseudo-op: `.variant_pcs'
/tmp/cc0eANtK.s:4164: Error: unknown pseudo-op: `.variant_pcs'
make[2]: *** [src/CMakeFiles/lib_darktable.dir/build.make:136: src/CMakeFiles/lib_darktable.dir/common/bilateral.c.o] Error 1
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [CMakeFiles/Makefile2:1829: src/CMakeFiles/lib_darktable.dir/all] Error 2
make: *** [Makefile:172: all] Error 2
```

Re: darktable-3.0.x: build fails for aarch64* with openmp

[Sturmflut]

[-- Attachment #1: Type: text/plain, Size: 1491 bytes --]

New comment by Sturmflut on void-packages repository

https://github.com/void-linux/void-packages/issues/21105#issuecomment-1229026639

Comment:
Funnily I came across my own post in this issue one and a half years later when trying to build darktable on a Raspberry Pi.

It looks like this problem still exists with GCC 10.2.1 and the current darktable master (I just tried commit ab7e374330a9e50abad0f2784bda4b319e770239, a bunch of commits after the 4.0 release).

An example for code that raises this error is:

```
// Kahan summation algorithm
#ifdef _OPENMP
#pragma omp declare simd aligned(c)
#endif
static inline float Kahan_sum(const float m, float *const __restrict__ c, const float add)
{
   const float t1 = add - (*c);
   const float t2 = m + t1;
   *c = (t2 - m) - t1;
   return t2;
}
```

The two `const float` are 32 bit, the `float *const` should be 64 bit on AArch64. The limitation that all types must be of the same length for OpenMD SIMD only exists for AArch64 in GCC, and this is still the case in the latest GCC 12.2.0. So it's basically possible to use all parts of OpenMP except SIMD.

Theoretically this should be accomplished with CFLAGS="-fopenmp -fno-openmp-simd". But it isn't. There is also no GCC macro to check for OpenMP SIMD support or something like that (see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80502), so apart from changing the code I don't see an other option than to completely disable OpenMP when building on AArch64.

Re: darktable-3.0.x: build fails for aarch64* with openmp

[lemmi]

[-- Attachment #1: Type: text/plain, Size: 144 bytes --]

New comment by lemmi on void-packages repository

https://github.com/void-linux/void-packages/issues/21105#issuecomment-1229129059

Comment:
Th

Re: darktable-3.0.x: build fails for aarch64* with openmp

[lemmi]

[-- Attachment #1: Type: text/plain, Size: 163 bytes --]

New comment by lemmi on void-packages repository

https://github.com/void-linux/void-packages/issues/21105#issuecomment-1229129059

Comment:
Thanks for the update

Re: darktable>=3.0.x: build fails for aarch64* with openmp

[lemmi]

[-- Attachment #1: Type: text/plain, Size: 1455 bytes --]

New comment by lemmi on void-packages repository

https://github.com/void-linux/void-packages/issues/21105#issuecomment-1229132479

Comment:
So this made me have another look, whether I couldn't find a solution upstream. Seems like the flag is also necessary on macos, but they also add [`-DBUILD_SSE2_CODEPATHS=OFF`](https://github.com/macports/macports-ports/blob/2f8fe26bae7c95d4c9bb1c0b1eae2f8c8e6161f7/graphics/darktable-devel/Portfile#L139).
That made me try to replace `-DUSE_OPENMP=OFF` with that:
```diff
diff --git a/srcpkgs/darktable/template b/srcpkgs/darktable/template
index 9d0ba9ba70..58fd4fd818 100644
--- a/srcpkgs/darktable/template
+++ b/srcpkgs/darktable/template
@@ -40,6 +40,6 @@ fi

 case $XBPS_TARGET_MACHINE in
        aarch64*)
-               configure_args+=" -DUSE_OPENMP=OFF"
+               configure_args+=" -DBUILD_SSE2_CODEPATHS=OFF"
                ;;
 esac
```
Maybe someone can try whether this produces a working binary?

Regardless, without `-DUSE_OPENMP=OFF` I still get
```
/builddir/darktable-4.0.0/src/common/iop_profile.h:286:20: warning: GCC does not currently support mixed size types for 'simd' functions
  286 | static inline void dt_ioppr_rgb_matrix_to_xyz(const dt_aligned_pixel_t rgb, dt_aligned_pixel_t xyz,
      |                    ^~~~~~~~~~~~~~~~~~~~~~~~~~
```
But these issues are now warnings (at least with `darktable-4.0`), not errors anymore and `darktable` compiles.

Re: darktable>=3.0.x: build fails for aarch64* with openmp

[Sturmflut]

[-- Attachment #1: Type: text/plain, Size: 796 bytes --]

New comment by Sturmflut on void-packages repository

https://github.com/void-linux/void-packages/issues/21105#issuecomment-1229178884

Comment:
`BUILD_SSE2_CODEPATHS=OFF` should be set automatically by CMake. `USE_OPENMP=OFF` is undesirable if you have more than one CPU core.

As a Proof-of-Concept, I converted all the `#ifdef _OPENMP` to `#if defined(_OPENMP) && !defined(__aarch64__)` if they wrapped around a `#pragma omp simd`. The attached patch does this for the current darktable master. It builds with OpenMP on a Raspberry Pi 3 and runs in parallel on all four cores.

Obviously this has to be fixed first and foremost in GCC. If the OpenMP standard supports mixed types for OpenMP SIMD and GCC supports mixed types on other platforms, it definitely also should do so on AArch64.

Re: darktable>=3.0.x: build fails for aarch64* with openmp

[lemmi]

[-- Attachment #1: Type: text/plain, Size: 255 bytes --]

New comment by lemmi on void-packages repository

https://github.com/void-linux/void-packages/issues/21105#issuecomment-1229192301

Comment:
Yeah, we shouldn't maintain such a patch, agreed.
Have you by any chance tried building `darktable` with `llvm`?

Re: darktable>=3.0.x: build fails for aarch64* with openmp

[Sturmflut]

[-- Attachment #1: Type: text/plain, Size: 1048 bytes --]

New comment by Sturmflut on void-packages repository

https://github.com/void-linux/void-packages/issues/21105#issuecomment-1229198160

Comment:
I just did. You need the following patch to get Clang 11 working:

```
--- a/src/is_supported_platform.h
+++ b/src/is_supported_platform.h
@@ -30,7 +30,7 @@
 #define DT_SUPPORTED_X86 0
 #endif
 
-#if defined(__aarch64__) && (defined(__ARM_64BIT_STATE) && defined(__ARM_ARCH) && defined(__ARM_ARCH_8A) || defined(__APPLE__) || defined(__MINGW64__))
+#if defined(__aarch64__) && (defined(__ARM_64BIT_STATE) && defined(__ARM_ARCH) && (defined(__ARM_ARCH_8A) || __ARM_ARCH_PROFILE == 'A') || defined(__APPLE__) || defined(__MINGW64__))
 #define DT_SUPPORTED_ARMv8A 1
 #else
 #define DT_SUPPORTED_ARMv8A 0
```

It compiles fine without any modifications to the OpenMP SIMD statements and the generated binary seems to work perfectly, utilizing all four cores on the Raspberry Pi 3 Model B.

I've sent a Pull Request with this patch to the darktable devs, see darktable-org/darktable#12388.

Re: darktable>=3.0.x: build fails for aarch64* with openmp

[lemmi]

[-- Attachment #1: Type: text/plain, Size: 477 bytes --]

New comment by lemmi on void-packages repository

https://github.com/void-linux/void-packages/issues/21105#issuecomment-1233440250

Comment:
@Sturmflut I see the patch was accepted upstream. This means we need to conditionally build `darktable` with `llvm`, correct? I need to wait for `4.0.1` anyway, since `4.0.0` has a couple of issue that need to be resolved. Do you already have something in place I can use for the `llvm` build, so I can potentially add this to `4.0.1`?

Re: darktable>=3.0.x: build fails for aarch64* with openmp

[github-actions]

[-- Attachment #1: Type: text/plain, Size: 293 bytes --]

New comment by github-actions[bot] on void-packages repository

https://github.com/void-linux/void-packages/issues/21105#issuecomment-1331550609

Comment:
Issues become stale 90 days after last activity and are closed 14 days after that.  If this issue is still relevant bump it or assign it.

Re: [ISSUE] [CLOSED] darktable>=3.0.x: build fails for aarch64* with openmp

[github-actions]

[-- Attachment #1: Type: text/plain, Size: 1387 bytes --]

Closed issue by lemmi on void-packages repository

https://github.com/void-linux/void-packages/issues/21105

Description:
Opening this issue to document the error when cross compiling darktable for aarch64:
```
/builddir/darktable-3.0.1/src/common/bilateral.c:332:6: warning: GCC does not currently support mixed size types for 'simd' functions
  332 | void dt_bilateral_slice_to_output(const dt_bilateral_t *const b, const float *const in, float *out,
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/builddir/darktable-3.0.1/src/common/bilateral.c:276:6: warning: GCC does not currently support mixed size types for 'simd' functions
  276 | void dt_bilateral_slice(const dt_bilateral_t *const b, const float *const in, float *out, const float detail)
      |      ^~~~~~~~~~~~~~~~~~
/tmp/cc0eANtK.s: Assembler messages:
/tmp/cc0eANtK.s:3724: Error: unknown pseudo-op: `.variant_pcs'
/tmp/cc0eANtK.s:3861: Error: unknown pseudo-op: `.variant_pcs'
/tmp/cc0eANtK.s:3986: Error: unknown pseudo-op: `.variant_pcs'
/tmp/cc0eANtK.s:4164: Error: unknown pseudo-op: `.variant_pcs'
make[2]: *** [src/CMakeFiles/lib_darktable.dir/build.make:136: src/CMakeFiles/lib_darktable.dir/common/bilateral.c.o] Error 1
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [CMakeFiles/Makefile2:1829: src/CMakeFiles/lib_darktable.dir/all] Error 2
make: *** [Makefile:172: all] Error 2
```