From 7a69d764b0ba06997cd9837a7db4bf247b0ac449 Mon Sep 17 00:00:00 2001
From: Hans-Kristian Arntzen <post@arntzen-software.no>
Date: Tue, 7 Jan 2020 11:36:51 +0100
Subject: [PATCH] MSL: Add trivial tests for Component decoration.

Verifies that Component decoration is honored for vertex outputs and
fragment inputs.
---
 .../components/fragment-input-component.frag  | 23 ++++++++++++++++
 .../components/vertex-output-component.vert   | 26 +++++++++++++++++++
 .../components/fragment-input-component.frag  | 10 +++++++
 .../components/vertex-output-component.vert   | 12 +++++++++
 spirv_msl.cpp                                 |  9 ++++++-
 5 files changed, 79 insertions(+), 1 deletion(-)
 create mode 100644 reference/shaders-msl-no-opt/components/fragment-input-component.frag
 create mode 100644 reference/shaders-msl-no-opt/components/vertex-output-component.vert
 create mode 100644 shaders-msl-no-opt/components/fragment-input-component.frag
 create mode 100644 shaders-msl-no-opt/components/vertex-output-component.vert

diff --git a/reference/shaders-msl-no-opt/components/fragment-input-component.frag b/reference/shaders-msl-no-opt/components/fragment-input-component.frag
new file mode 100644
index 00000000..9a65918a
--- /dev/null
+++ b/reference/shaders-msl-no-opt/components/fragment-input-component.frag
@@ -0,0 +1,23 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct main0_out
+{
+    float4 FragColor [[color(0)]];
+};
+
+struct main0_in
+{
+    float3 Foo3 [[user(locn0)]];
+    float Foo1 [[user(locn0_3)]];
+};
+
+fragment main0_out main0(main0_in in [[stage_in]])
+{
+    main0_out out = {};
+    out.FragColor = float4(in.Foo3, in.Foo1);
+    return out;
+}
+
diff --git a/reference/shaders-msl-no-opt/components/vertex-output-component.vert b/reference/shaders-msl-no-opt/components/vertex-output-component.vert
new file mode 100644
index 00000000..cf135b51
--- /dev/null
+++ b/reference/shaders-msl-no-opt/components/vertex-output-component.vert
@@ -0,0 +1,26 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct main0_out
+{
+    float3 Foo3 [[user(locn0)]];
+    float Foo1 [[user(locn0_3)]];
+    float4 gl_Position [[position]];
+};
+
+struct main0_in
+{
+    float4 vFoo [[attribute(0)]];
+};
+
+vertex main0_out main0(main0_in in [[stage_in]])
+{
+    main0_out out = {};
+    out.gl_Position = in.vFoo;
+    out.Foo3 = in.vFoo.xyz;
+    out.Foo1 = in.vFoo.w;
+    return out;
+}
+
diff --git a/shaders-msl-no-opt/components/fragment-input-component.frag b/shaders-msl-no-opt/components/fragment-input-component.frag
new file mode 100644
index 00000000..60d48bef
--- /dev/null
+++ b/shaders-msl-no-opt/components/fragment-input-component.frag
@@ -0,0 +1,10 @@
+#version 450
+
+layout(location = 0, component = 3) in float Foo1;
+layout(location = 0, component = 0) in vec3 Foo3;
+layout(location = 0) out vec4 FragColor;
+
+void main()
+{
+	FragColor = vec4(Foo3, Foo1);
+}
diff --git a/shaders-msl-no-opt/components/vertex-output-component.vert b/shaders-msl-no-opt/components/vertex-output-component.vert
new file mode 100644
index 00000000..5abd8dc6
--- /dev/null
+++ b/shaders-msl-no-opt/components/vertex-output-component.vert
@@ -0,0 +1,12 @@
+#version 450
+
+layout(location = 0) in vec4 vFoo;
+layout(location = 0) out vec3 Foo3;
+layout(location = 0, component = 3) out float Foo1;
+
+void main()
+{
+	gl_Position = vFoo;
+	Foo3 = vFoo.xyz;
+	Foo1 = vFoo.w;
+}
diff --git a/spirv_msl.cpp b/spirv_msl.cpp
index 53e6f32f..a2b3a349 100644
--- a/spirv_msl.cpp
+++ b/spirv_msl.cpp
@@ -8604,7 +8604,14 @@ string CompilerMSL::member_attribute_qualifier(const SPIRType &type, uint32_t in
 			uint32_t locn = get_ordered_member_location(type.self, index, &comp);
 			if (locn != k_unknown_location)
 			{
-				if (comp != k_unknown_component)
+				// For user-defined attributes, this is fine. From Vulkan spec:
+				// A user-defined output variable is considered to match an input variable in the subsequent stage if
+				// the two variables are declared with the same Location and Component decoration and match in type
+				// and decoration, except that interpolation decorations are not required to match. For the purposes
+				// of interface matching, variables declared without a Component decoration are considered to have a
+				// Component decoration of zero.
+
+				if (comp != k_unknown_component && comp != 0)
 					quals = string("user(locn") + convert_to_string(locn) + "_" + convert_to_string(comp) + ")";
 				else
 					quals = string("user(locn") + convert_to_string(locn) + ")";