build: detect Metal.framework and build .metal files

Reviewed-by: Ridley Combs <rcombs@rcombs.me>
Signed-off-by: Aman Karmani <aman@tmm1.net>

.gitignore

@@ -19,6 +19,9 @@
 *.swp
 *.ver
 *.version
+*.metal.air
+*.metallib
+*.metallib.c
 *.ptx
 *.ptx.c
 *.ptx.gz

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 +383,8 @@ 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]
+  --metallib=METALLIB      use metal linker METALLIB [$metallib_default]
   --pkg-config=PKGCONFIG   use pkg-config tool PKGCONFIG [$pkg_config_default]
   --pkg-config-flags=FLAGS pass additional flags to pkgconf []
   --ranlib=RANLIB          use ranlib RANLIB [$ranlib_default]
@@ -2564,6 +2567,8 @@ CMDLINE_SET="
     ln_s
     logfile
     malloc_prefix
+    metalcc
+    metallib
     nm
     optflags
     nvcc
@@ -3835,6 +3840,8 @@ host_cc_default="gcc"
 doxygen_default="doxygen"
 install="install"
 ln_s_default="ln -s -f"
+metalcc_default="xcrun metal"
+metallib_default="xcrun metallib"
 nm_default="nm -g"
 pkg_config_default=pkg-config
 ranlib_default="ranlib"
@@ -4435,7 +4442,7 @@ if enabled cuda_nvcc; then
 fi
 
 set_default arch cc cxx doxygen pkg_config ranlib strip sysinclude \
-    target_exec x86asmexe
+    target_exec x86asmexe metalcc metallib
 enabled cross_compile || host_cc_default=$cc
 set_default host_cc
 
@@ -6326,6 +6333,7 @@ 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 +7628,8 @@ ARFLAGS=$arflags
 AR_O=$ar_o
 AR_CMD=$ar
 NM_CMD=$nm
+METALCC=$metalcc
+METALLIB=$metallib
 RANLIB=$ranlib
 STRIP=$strip
 STRIPTYPE=$striptype

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
+	$(METALLIB) --split-module-without-linking $(patsubst $(SRC_PATH)/%,$(SRC_LINK)/%,$<) -o $@
+
+%.metallib.c: %.metallib $(BIN2CEXE)
+	$(BIN2C) $(patsubst $(SRC_PATH)/%,$(SRC_LINK)/%,$<) $@ $(subst .,_,$(basename $(notdir $@)))
+
 %.ptx: %.cu $(SRC_PATH)/compat/cuda/cuda_runtime.h
 	$(COMPILE_NVCC)