Add basic setup for regression testing Metal output.

.travis.yml

@@ -24,3 +24,4 @@ script:
   - make -j2
   - PATH=./glslang/StandAlone:./SPIRV-Tools/tools:$PATH
   - ./test_shaders.py shaders
+  - ./test_shaders.py --metal shaders-msl

CMakeLists.txt

@@ -93,6 +93,9 @@ if (${PYTHONINTERP_FOUND})
 	add_test(NAME spirv-cross-test
 		COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/test_shaders.py
 			${CMAKE_CURRENT_SOURCE_DIR}/shaders)
+	add_test(NAME spirv-cross-test-metal
+		COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/test_shaders.py --metal
+			${CMAKE_CURRENT_SOURCE_DIR}/shaders-msl)
   endif()
 else()
   message(WARNING "Testing disabled. Could not find python3. If you have python3 installed try running "

README.md

@@ -171,6 +171,8 @@ In these cases, run `./test_shaders.py shaders --update` to update the reference
 Always make sure you are running up to date glslangValidator as well as SPIRV-Tools when updating reference files.
 
 In short, the master branch should always be able to run `./test_shaders.py shaders` without failure.
+SPIRV-Cross uses Travis CI to test all pull requests, so it is not strictly needed to perform testing yourself if you have problems running it locally.
+A pull request which does not pass testing on Travis will not be accepted however.
 
 When adding support for new features to SPIRV-Cross, a new shader and reference file should be added which covers usage of the new shader features in question.
 
@@ -205,6 +207,10 @@ The current reference output is contained in reference/.
 
 See `./test_shaders.py --help` for more.
 
+### Metal backend
+
+To test the roundtrip path GLSL -> SPIR-V -> MSL, `--metal` can be added, e.g. `./test_shaders.py --metal shaders-msl`.
+
 ### Updating regression tests
 
 When legitimate changes are found, use `--update` flag to update regression files.

reference/shaders-msl/vert/basic.vert

@@ -0,0 +1,32 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct UBO
+{
+    float4x4 uMVP;
+};
+
+struct main0_in
+{
+    float4 aVertex [[attribute(0)]];
+    float3 aNormal [[attribute(0)]];
+};
+
+struct main0_out
+{
+    float3 vNormal [[user(locn0)]];
+    float4 gl_Position [[position]];
+    float gl_PointSize;
+};
+
+vertex main0_out main0(main0_in in [[stage_in]], constant UBO& _16 [[buffer(0)]])
+{
+    main0_out out = {};
+    out.gl_Position = _16.uMVP * in.aVertex;
+    out.vNormal = in.aNormal;
+    out.gl_Position.y = -(out.gl_Position.y);    // Invert Y-axis for Metal
+    return out;
+}
+

shaders-msl/vert/basic.vert

@@ -0,0 +1,15 @@
+#version 310 es
+
+layout(std140) uniform UBO
+{
+    uniform mat4 uMVP;
+};
+in vec4 aVertex;
+in vec3 aNormal;
+out vec3 vNormal;
+
+void main()
+{
+    gl_Position = uMVP * aVertex;
+    vNormal = aNormal;
+}

test_shaders.py

@@ -66,6 +66,19 @@ def validate_shader(shader, vulkan):
     else:
         subprocess.check_call(['glslangValidator', shader])
 
+def cross_compile_msl(shader):
+    spirv_f, spirv_path = tempfile.mkstemp()
+    msl_f, msl_path = tempfile.mkstemp(suffix = os.path.basename(shader))
+    os.close(spirv_f)
+    os.close(msl_f)
+    subprocess.check_call(['glslangValidator', '-V', '-o', spirv_path, shader])
+    spirv_cross_path = './spirv-cross'
+    subprocess.check_call([spirv_cross_path, '--entry', 'main', '--output', msl_path, spirv_path, '--metal'])
+    subprocess.check_call(['spirv-val', spirv_path])
+
+    # TODO: Add optional validation of the MSL output.
+    return (spirv_path, msl_path)
+
 def cross_compile(shader, vulkan, spirv, invalid_spirv, eliminate, is_legacy, flatten_ubo):
     spirv_f, spirv_path = tempfile.mkstemp()
     glsl_f, glsl_path = tempfile.mkstemp(suffix = os.path.basename(shader))
@@ -212,20 +225,30 @@ def test_shader(stats, shader, update, keep):
             a.append(str(i))
         print(','.join(a), file = stats)
 
-def test_shaders_helper(stats, shader_dir, update, malisc, keep):
+def test_shader_msl(stats, shader, update, keep):
+    joined_path = os.path.join(shader[0], shader[1])
+    print('Testing MSL shader:', joined_path)
+    spirv, msl = cross_compile_msl(joined_path)
+    regression_check(shader, msl, update, keep)
+    os.remove(spirv)
+
+def test_shaders_helper(stats, shader_dir, update, malisc, keep, backend):
     for root, dirs, files in os.walk(os.path.join(shader_dir)):
         for i in files:
             path = os.path.join(root, i)
             relpath = os.path.relpath(path, shader_dir)
-            test_shader(stats, (shader_dir, relpath), update, keep)
+            if backend == 'metal':
+                test_shader_msl(stats, (shader_dir, relpath), update, keep)
+            else:
+                test_shader(stats, (shader_dir, relpath), update, keep)
 
-def test_shaders(shader_dir, update, malisc, keep):
+def test_shaders(shader_dir, update, malisc, keep, backend):
     if malisc:
         with open('stats.csv', 'w') as stats:
             print('Shader,OrigRegs,OrigUniRegs,OrigALUShort,OrigLSShort,OrigTEXShort,OrigALULong,OrigLSLong,OrigTEXLong,CrossRegs,CrossUniRegs,CrossALUShort,CrossLSShort,CrossTEXShort,CrossALULong,CrossLSLong,CrossTEXLong', file = stats)
-            test_shaders_helper(stats, shader_dir, update, malisc, keep)
+            test_shaders_helper(stats, shader_dir, update, malisc, keep, backend)
     else:
-        test_shaders_helper(None, shader_dir, update, malisc, keep)
+        test_shaders_helper(None, shader_dir, update, malisc, keep, backend)
 
 def main():
     parser = argparse.ArgumentParser(description = 'Script for regression testing.')
@@ -240,13 +263,16 @@ def main():
     parser.add_argument('--malisc',
             action = 'store_true',
             help = 'Use malisc offline compiler to determine static cycle counts before and after spirv-cross.')
+    parser.add_argument('--metal',
+            action = 'store_true',
+            help = 'Test Metal backend.')
     args = parser.parse_args()
 
     if not args.folder:
         sys.stderr.write('Need shader folder.\n')
         sys.exit(1)
 
-    test_shaders(args.folder, args.update, args.malisc, args.keep)
+    test_shaders(args.folder, args.update, args.malisc, args.keep, 'metal' if args.metal else 'glsl')
     if args.malisc:
         print('Stats in stats.csv!')
     print('Tests completed!')