[FFmpeg-devel] [PATCH v3 2/5] build: detect Metal.framework and build .metal files

[Martin Storsjö]

On Thu, 16 Dec 2021, Aman Karmani wrote:

> From: Aman Karmani <aman at tmm1.net>
>
> Signed-off-by: Aman Karmani <aman at tmm1.net>
> ---
> .gitignore         | 3 +++
> configure          | 8 +++++++-
> ffbuild/common.mak | 9 +++++++++
> 3 files changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/.gitignore b/.gitignore
> index 9ed24b542e..1a5bb29ad5 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -19,6 +19,9 @@
> *.swp
> *.ver
> *.version
> +*.metal.air
> +*.metallib
> +*.metallib.c
> *.ptx
> *.ptx.c
> *.ptx.gz
> diff --git a/configure b/configure
> index 5fffcb8afe..ab00b2d7cb 100755
> --- a/configure
> +++ b/configure
> @@ -309,6 +309,7 @@ External library support:
>                            if openssl, gnutls or libtls is not used [no]
>   --enable-mediacodec      enable Android MediaCodec support [no]
>   --enable-mediafoundation enable encoding via MediaFoundation [auto]
> +  --disable-metal          disable Apple Metal framework [autodetect]
>   --enable-libmysofa       enable libmysofa, needed for sofalizer filter [no]
>   --enable-openal          enable OpenAL 1.1 capture support [no]
>   --enable-opencl          enable OpenCL processing [no]
> @@ -382,6 +383,7 @@ Toolchain options:
>   --dep-cc=DEPCC           use dependency generator DEPCC [$cc_default]
>   --nvcc=NVCC              use Nvidia CUDA compiler NVCC or clang [$nvcc_default]
>   --ld=LD                  use linker LD [$ld_default]
> +  --metalcc=METALCC        use metal compiler METALCC [$metalcc_default]
>   --pkg-config=PKGCONFIG   use pkg-config tool PKGCONFIG [$pkg_config_default]
>   --pkg-config-flags=FLAGS pass additional flags to pkgconf []
>   --ranlib=RANLIB          use ranlib RANLIB [$ranlib_default]
> @@ -2564,6 +2566,7 @@ CMDLINE_SET="
>     ln_s
>     logfile
>     malloc_prefix
> +    metalcc
>     nm
>     optflags
>     nvcc
> @@ -3835,6 +3838,7 @@ host_cc_default="gcc"
> doxygen_default="doxygen"
> install="install"
> ln_s_default="ln -s -f"
> +metalcc_default="xcrun metal"
> nm_default="nm -g"
> pkg_config_default=pkg-config
> ranlib_default="ranlib"
> @@ -4435,7 +4439,7 @@ if enabled cuda_nvcc; then
> fi
>
> set_default arch cc cxx doxygen pkg_config ranlib strip sysinclude \
> -    target_exec x86asmexe
> +    target_exec x86asmexe metalcc
> enabled cross_compile || host_cc_default=$cc
> set_default host_cc
>
> @@ -6326,6 +6330,7 @@ check_apple_framework CoreFoundation
> check_apple_framework CoreMedia
> check_apple_framework CoreVideo
> check_apple_framework CoreAudio
> +check_apple_framework Metal
>
> enabled avfoundation && {
>     disable coregraphics applicationservices
> @@ -7620,6 +7625,7 @@ ARFLAGS=$arflags
> AR_O=$ar_o
> AR_CMD=$ar
> NM_CMD=$nm
> +METALCC=$metalcc
> RANLIB=$ranlib
> STRIP=$strip
> STRIPTYPE=$striptype
> diff --git a/ffbuild/common.mak b/ffbuild/common.mak
> index 0eb831d434..05440911f4 100644
> --- a/ffbuild/common.mak
> +++ b/ffbuild/common.mak
> @@ -112,6 +112,15 @@ COMPILE_LASX = $(call COMPILE,CC,LASXFLAGS)
> $(BIN2CEXE): ffbuild/bin2c_host.o
> 	$(HOSTLD) $(HOSTLDFLAGS) $(HOSTLD_O) $^ $(HOSTEXTRALIBS)
>
> +%.metal.air: %.metal
> +	$(METALCC) $(patsubst $(SRC_PATH)/%,$(SRC_LINK)/%,$<) -o $@
> +
> +%.metallib: %.metal.air
> +	$(METALCC)lib --split-module-without-linking $(patsubst $(SRC_PATH)/%,$(SRC_LINK)/%,$<) -o $@

Hmm, so does this try to run "xcrun metallib" instead of "xcrun metal"? I 
think that can be kinda brittle, e.g. if someone wants to configure a 
custom build env, where METALCC expands to e.g. 
"my-wrapped-metal-compiler.sh".

I guess it feels a bit boring to need to define two separate variables, 
but if it really is two separate tools, then I think that'd be the best 
for clarity.

// Martin