MSL: Add options to control emission of fragment outputs.

Like with `point_size` when not rendering points, Metal complains when
writing to a variable using the `[[depth]]` qualifier when no depth
buffer be attached. In that case, we must avoid emitting `FragDepth`,
just like with `PointSize`.

I assume it will also complain if there be no stencil attachment and the
shader write to `[[stencil]]`, or it write to `[[color(n)]]` but there
be no color attachment at n.

1 files changed, 6 insertions, 0 deletions

diff --git a/test_shaders.py b/test_shaders.py
index 7b68766d..621df273 100755
--- a/test_shaders.py
+++ b/test_shaders.py
@@ -258,6 +258,12 @@ def cross_compile_msl(shader, spirv, opt, iterations, paths):
         msl_args.append('--msl-force-native-arrays')
     if '.zero-initialize.' in shader:
         msl_args.append('--force-zero-initialized-variables')
+    if '.frag-output.' in shader:
+        # Arbitrary for testing purposes.
+        msl_args.append('--msl-disable-frag-depth-builtin')
+        msl_args.append('--msl-disable-frag-stencil-ref-builtin')
+        msl_args.append('--msl-enable-frag-output-mask')
+        msl_args.append('0x000000ca')
 
     subprocess.check_call(msl_args)