Merge pull request #1303 from KhronosGroup/fix-1302

MSL: Fix access chain for deep struct hierarchy on array of buffers.

reference/shaders-msl-no-opt/frag/ubo-array-multiple-structs-access-chain.argument.msl2.frag

@@ -0,0 +1,32 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct Foo
+{
+    float4 v;
+};
+
+struct UBO
+{
+    Foo foo;
+};
+
+struct spvDescriptorSetBuffer0
+{
+    constant UBO* ubos [[id(0)]][2];
+};
+
+struct main0_out
+{
+    float4 FragColor [[color(0)]];
+};
+
+fragment main0_out main0(constant spvDescriptorSetBuffer0& spvDescriptorSet0 [[buffer(0)]])
+{
+    main0_out out = {};
+    out.FragColor = spvDescriptorSet0.ubos[1]->foo.v;
+    return out;
+}
+

reference/shaders-msl-no-opt/frag/ubo-array-multiple-structs-access-chain.frag

@@ -0,0 +1,33 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct Foo
+{
+    float4 v;
+};
+
+struct UBO
+{
+    Foo foo;
+};
+
+struct main0_out
+{
+    float4 FragColor [[color(0)]];
+};
+
+fragment main0_out main0(constant UBO* ubos_0 [[buffer(0)]], constant UBO* ubos_1 [[buffer(1)]])
+{
+    constant UBO* ubos[] =
+    {
+        ubos_0,
+        ubos_1,
+    };
+
+    main0_out out = {};
+    out.FragColor = ubos[1]->foo.v;
+    return out;
+}
+

shaders-msl-no-opt/frag/ubo-array-multiple-structs-access-chain.argument.msl2.frag

@@ -0,0 +1,18 @@
+#version 450
+
+struct Foo
+{
+	vec4 v;
+};
+
+layout(set = 0, binding = 0) uniform UBO
+{
+	Foo foo;
+} ubos[2];
+
+layout(location = 0) out vec4 FragColor;
+
+void main()
+{
+	FragColor = ubos[1].foo.v;
+}

shaders-msl-no-opt/frag/ubo-array-multiple-structs-access-chain.frag

@@ -0,0 +1,18 @@
+#version 450
+
+struct Foo
+{
+	vec4 v;
+};
+
+layout(set = 0, binding = 0) uniform UBO
+{
+	Foo foo;
+} ubos[2];
+
+layout(location = 0) out vec4 FragColor;
+
+void main()
+{
+	FragColor = ubos[1].foo.v;
+}

spirv_msl.cpp

@@ -10505,7 +10505,12 @@ string CompilerMSL::to_member_reference(uint32_t base, const SPIRType &type, uin
 
 	if (var)
 	{
-		bool is_buffer_variable = var->storage == StorageClassUniform || var->storage == StorageClassStorageBuffer;
+		// Only allow -> dereference for block types. This is so we get expressions like
+		// buffer[i]->first_member.second_member, rather than buffer[i]->first->second.
+		bool is_block = has_decoration(type.self, DecorationBlock) || has_decoration(type.self, DecorationBufferBlock);
+
+		bool is_buffer_variable =
+		    is_block && (var->storage == StorageClassUniform || var->storage == StorageClassStorageBuffer);
 		declared_as_pointer = is_buffer_variable && is_array(get<SPIRType>(var->basetype));
 	}