cmake: backport support for vendored libavif to SDL2_image

[sezero]

@madebr: Please review this.

There is a CI run failure with MacOS vendored build like:

   "_dav1d_warp_affine_8x8_8bpc_sse2", referenced from:
      _dav1d_mc_dsp_init_8bpc in mc_tmpl.c.o

... but I think that is a problem with your dav1d cmake support
and not with this backport: I think dav1d is built with either
incorrect nasm output format flags or without any flags at all.
In mac case, we want -fmacho, in windows case we want -fwin,
and in linux/elf case we want -felf, and all need appending a
32 or 64 depending on x86 or x64 target.

[sezero]

OK, I cross-built dav1d for x86_64 mac, the same errors, and cmake
seems to use -f macho64 correctly. On the other hand build using
meson as a dylib with the same environment succeeds.

The problem seems to be with symbol decoration: macho and windows-
x86 symbols must be prefixed with and underscore. This probably has
something to do with meson defining PREFIX macro...

[sezero]

For reference, here are the configs generated by meson: meson_configs.zip

[sezero]

Manually adding PREFIX define in config.asm and config.h generated
by your dav1d cmake port: build succeeds.

However: There seem to be more missing stuff in dav1d cmake port,
one such thing is STACK_ALIGNMENT in config.asm. There may be others.

Is it not possible to run meson configurator from within cmake??

[sezero]

Is it not possible to run meson configurator from within cmake??

I could find https://discourse.cmake.org/t/3985 and
https://cmake.org/cmake/help/latest/module/ExternalProject.html,
but I'm not fluent enough with cmake to make use of them

[sezero]

The following seems to work for me and seems to match meson better.
Tested by cross-compiling dav1d as an x86_64 dylib. @madebr: Please
review.
[EDIT: patch applied to dav1d, see next post for discussion]

[sezero]

OK, I pushed libsdl-org/dav1d@66d3dd8 to our dav1d 1.2.1-SDL branch and bumped the dav1d revision here accordingly. The CI link failure seems to be cured. @madebr: Please confirm that things are in order. If you confirm, I will bump it in SDL3 branch too.

@slouken: Noticed a few things in your dav1d Android configuration:

• PREFIX is defined in all configs: Is that accurate, or some copy/paste artifact?

• There is no config.asm in none of the configs.

• STACK_ALIGNMENT is defined as 32: is that deliberately picked? Because meson build systems defines it either as 4 or 16 unless user-specified.

• STACK_ALIGNMENT is defined only for x86_64 config but not arm configs: Intentional??

• EDIT: Same arguments for the dav1d configs in SDL_image/Xcode (except for PREFIX which is really needed when targeting APPLE platforms.)

[madebr]

Your dav1d changes look fine, I have these suggestions:

• Make TRIM_DSP_FUNCTIONS a compile definitions, instead of adding it to the config file. CMAKE_BUILD_TYPE is not defined for multi-config generators, such as Visual Studio.
• Make DAV1D_STACK_ALIGNMENT a configurable option, that can be overriden by users.

--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -151,19 +151,15 @@ else()
   set(CONFIG_LOG 0)
 endif()
 
-list(APPEND config01_variables TRIM_DSP_FUNCTIONS)
-if(CMAKE_BUILD_TYPE STREQUAL "Release" OR
-   CMAKE_BUILD_TYPE STREQUAL "MinSizeRel")
-set(TRIM_DSP_FUNCTIONS 1)
-endif()
+# TRIM_DSP_FUNCTIONS=1 if Release or Debug mode
+add_definitions(-DTRIM_DSP_FUNCTIONS=$<BOOL:$<OR:$<CONFIG:Release>,$<CONFIG:MinSizeRel>>>)
 
-if(NOT DAV1D_STACK_ALIGNMENT)
-  if(DAV1D_CPU_X64 OR APPLE OR (CMAKE_SYSTEM_NAME MATCHES ".*Linux"))
-    set(DAV1D_STACK_ALIGNMENT 16)
-  else()
-    set(DAV1D_STACK_ALIGNMENT 4)
-  endif()
+if(DAV1D_CPU_X64 OR APPLE OR CMAKE_SYSTEM_NAME MATCHES ".*Linux")
+    set(DAV1D_STACK_ALIGNMENT_DEFAULT 16)
+else()
+    set(DAV1D_STACK_ALIGNMENT_DEFAULT 4)
 endif()
+set(DAV1D_STACK_ALIGNMENT "${DAV1D_STACK_ALIGNMENT_DEFAULT}" CACHE STRING "Dav1d stack alignment")
 list(APPEND config_variables_value STACK_ALIGNMENT)
 set(STACK_ALIGNMENT ${DAV1D_STACK_ALIGNMENT})

Is it not possible to run meson configurator from within cmake??

I could find https://discourse.cmake.org/t/3985 and https://cmake.org/cmake/help/latest/module/ExternalProject.html, but I'm not fluent enough with cmake to make use of them

I tried this approach and asked on the #cmake channel on cpplang.slack.com, but got no satisfying answer (apart from people telling me they got no interest in cmake, or that I should use a package manager).
While trying, I had to auto-generate a "cross build definition file" for meson which I can't do for all toolchains + cmake gnerators.

[sezero]

Your dav1d changes look fine, I have these suggestions:

* Make `TRIM_DSP_FUNCTIONS` a compile definitions, instead of adding it to the config file. `CMAKE_BUILD_TYPE` is not defined for multi-config generators, such as Visual Studio.

OK

* Make `DAV1D_STACK_ALIGNMENT` a configurable option, that can be overriden by users.

[...]
+if(DAV1D_CPU_X64 OR APPLE OR CMAKE_SYSTEM_NAME MATCHES ".*Linux")
+    set(DAV1D_STACK_ALIGNMENT_DEFAULT 16)
+else()
+    set(DAV1D_STACK_ALIGNMENT_DEFAULT 4)
 endif()
+set(DAV1D_STACK_ALIGNMENT "${DAV1D_STACK_ALIGNMENT_DEFAULT}" CACHE STRING "Dav1d stack alignment")

OK. It's guaranteed that cmdline arg like -DDAV1D_STACK_ALIGNMENT works here, yes?

Is it not possible to run meson configurator from within cmake??

I could find https://discourse.cmake.org/t/3985 and https://cmake.org/cmake/help/latest/module/ExternalProject.html, but I'm not fluent enough with cmake to make use of them

I tried this approach and asked on the #cmake channel on cpplang.slack.com, but got no satisfying answer (apart from people telling me they got no interest in cmake, or that I should use a package manager). While trying, I had to auto-generate a "cross build definition file" for meson which I can't do for all toolchains + cmake gnerators.

OK, then.

[sezero]

OK. It's guaranteed that cmdline arg like -DDAV1D_STACK_ALIGNMENT works here, yes?

OK, stopped beign lazy and confirmed that it works, pushed the suggested changes to dav1d, bumped the rev here.

Is this PR good?

@slouken: Comments for the notes I wrote about your Android and Xcode configs?

[sezero]

One thing I'm curious about is that how this is happening with MSVC:

-- Performing Test LINKER_SUPPORTS_NO_UNDEFINED - Success

[madebr]

One thing I'm curious about is that how this is happening with MSVC:

-- Performing Test LINKER_SUPPORTS_NO_UNDEFINED - Success

SDL3 has this too. The MSVC linker emits a warning, not an error, when it receives an unknown argument.
There is a cmake issue tracking this.

[sezero]

One thing I'm curious about is that how this is happening with MSVC:

-- Performing Test LINKER_SUPPORTS_NO_UNDEFINED - Success

SDL3 has this too. The MSVC linker emits a warning, not an error, when it receives an unknown argument. There is a cmake issue tracking this.

Well, we should restrict that to non-windows.. (And also to non-openbsd like SDL2/3..)

[sezero]

Anyways, merging this patch. The rest should be subject to new tickets.