Bug 1692940 - Switch vpx build to nasm instead of yasm. r=firefox-build-system-reviewers,dmajor

We also remove the dependency on the check for GNU as, because all the
build environments we support for arm use GNU as, and the dependency
causes complications.

Differential Revision: https://phabricator.services.mozilla.com/D105427

media/libvpx/moz.build

@@ -9,8 +9,8 @@ with Files('*'):
 
 include('sources.mozbuild')
 
-if CONFIG['VPX_USE_YASM']:
-    USE_YASM = True
+if CONFIG['VPX_USE_NASM']:
+    USE_NASM = True
 
 # Linux, Mac and Win share file lists for x86* but not configurations.
 if CONFIG['CPU_ARCH'] == 'x86_64':

toolkit/moz.configure

@@ -1672,21 +1672,21 @@ with only_when(compile_environment):
 
         set_config("MOZ_SYSTEM_LIBVPX", True)
 
-    @depends("--with-system-libvpx", target, gnu_as)
-    def in_tree_vpx(system_libvpx, target, gnu_as):
+    @depends("--with-system-libvpx", target)
+    def in_tree_vpx(system_libvpx, target):
         if system_libvpx:
             return
 
-        use_yasm = (target.cpu in ("x86", "x86_64")) or None
-        need_yasm = False
-        arm_asm = (target.cpu == "arm" and gnu_as) or None
+        arm_asm = (target.cpu == "arm") or None
+        return namespace(arm_asm=arm_asm)
 
-        if use_yasm:
-            need_yasm = True
+    @depends(target, when=in_tree_vpx)
+    def vpx_nasm(target):
+        if target.cpu in ("x86", "x86_64"):
             if target.kernel == "WINNT":
-                need_yasm = Version("1.1")
-
-        return namespace(arm_asm=arm_asm, use_yasm=use_yasm, need_yasm=need_yasm)
+                # Version 2.03 is needed for automatic safeseh support.
+                return namespace(version="2.03", what="VPX")
+            return namespace(what="VPX")
 
     # Building with -mfpu=neon requires either the "softfp" or the
     # "hardfp" ABI. Depending on the compiler's default target, and the
@@ -1707,8 +1707,8 @@ with only_when(compile_environment):
         when=in_tree_vpx.arm_asm,
     )
 
-    @depends(in_tree_vpx, softfp, target)
-    def vpx_as_flags(vpx, softfp, target):
+    @depends(in_tree_vpx, vpx_nasm, softfp, target)
+    def vpx_as_flags(vpx, vpx_nasm, softfp, target):
         flags = []
         if vpx and vpx.arm_asm:
             # These flags are a lie; they're just used to enable the requisite
@@ -1716,11 +1716,11 @@ with only_when(compile_environment):
             flags = ["-march=armv7-a", "-mfpu=neon"]
             if softfp:
                 flags.append("-mfloat-abi=softfp")
-        elif vpx and vpx.use_yasm and target.os != "WINNT" and target.cpu != "x86_64":
+        elif vpx and vpx_nasm and target.os != "WINNT" and target.cpu != "x86_64":
             flags = ["-DPIC"]
         return flags
 
-    set_config("VPX_USE_YASM", in_tree_vpx.use_yasm)
+    set_config("VPX_USE_NASM", True, when=vpx_nasm)
     set_config("VPX_ASFLAGS", vpx_as_flags)
 
 
@@ -1921,14 +1921,12 @@ with only_when(compile_environment | artifact_builds):
 
 @depends(
     yasm_version,
-    in_tree_vpx.need_yasm,
     in_tree_jpeg.use_yasm,
     ffvpx.need_yasm,
 )
-def valid_yasm_version(yasm_version, for_vpx, for_jpeg, for_ffvpx=False):
+def valid_yasm_version(yasm_version, for_jpeg, for_ffvpx=False):
     # Note: the default for for_ffvpx above only matters for unit tests.
     requires = {
-        "vpx": for_vpx,
         "jpeg": for_jpeg,
         "ffvpx": for_ffvpx,
     }
@@ -1957,7 +1955,7 @@ def valid_yasm_version(yasm_version, for_vpx, for_jpeg, for_ffvpx=False):
 
 # nasm detection
 # ==============================================================
-@depends(dav1d_nasm)
+@depends(dav1d_nasm, vpx_nasm)
 def need_nasm(*requirements):
     requires = {
         x.what: x.version if hasattr(x, "version") else True for x in requirements if x