Merge pull request #136 from KhronosGroup/hlsl-builtin

Rewrite HLSL backend handling of inputs and outputs.

reference/shaders-hlsl/frag/basic.frag

@@ -4,15 +4,15 @@ static float4 FragColor;
 static float4 vColor;
 static float2 vTex;
 
-struct InputFrag
+struct SPIRV_Cross_Input
 {
     float4 vColor : TEXCOORD0;
     float2 vTex : TEXCOORD1;
 };
 
-struct OutputFrag
+struct SPIRV_Cross_Output
 {
-    float4 FragColor : COLOR;
+    float4 FragColor : SV_Target0;
 };
 
 void frag_main()
@@ -20,12 +20,12 @@ void frag_main()
     FragColor = vColor * tex2D(uTex, vTex);
 }
 
-OutputFrag main(InputFrag input)
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
 {
-    vColor = input.vColor;
-    vTex = input.vTex;
+    vColor = stage_input.vColor;
+    vTex = stage_input.vTex;
     frag_main();
-    OutputFrag output;
-    output.FragColor = FragColor;
-    return output;
+    SPIRV_Cross_Output stage_output;
+    stage_output.FragColor = FragColor;
+    return stage_output;
 }

reference/shaders-hlsl/frag/builtins.frag

@@ -0,0 +1,33 @@
+static float4 gl_FragCoord;
+static float gl_FragDepth;
+static float4 FragColor;
+static float4 vColor;
+
+struct SPIRV_Cross_Input
+{
+    float4 gl_FragCoord : SV_Position;
+    float4 vColor : TEXCOORD0;
+};
+
+struct SPIRV_Cross_Output
+{
+    float gl_FragDepth : SV_Depth;
+    float4 FragColor : SV_Target0;
+};
+
+void frag_main()
+{
+    FragColor = gl_FragCoord + vColor;
+    gl_FragDepth = 0.5f;
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    gl_FragCoord = stage_input.gl_FragCoord;
+    vColor = stage_input.vColor;
+    frag_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_FragDepth = gl_FragDepth;
+    stage_output.FragColor = FragColor;
+    return stage_output;
+}

reference/shaders-hlsl/frag/io-block.frag

@@ -0,0 +1,28 @@
+static float4 FragColor;
+
+struct VertexOut
+{
+    float4 a : TEXCOORD1;
+    float4 b : TEXCOORD2;
+};
+
+static VertexOut _12;
+
+struct SPIRV_Cross_Output
+{
+    float4 FragColor : SV_Target0;
+};
+
+void frag_main()
+{
+    FragColor = _12.a + _12.b;
+}
+
+SPIRV_Cross_Output main(in VertexOut stage_input_12)
+{
+    _12 = stage_input_12;
+    frag_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.FragColor = FragColor;
+    return stage_output;
+}

reference/shaders-hlsl/frag/mrt.frag

@@ -0,0 +1,31 @@
+static float4 RT0;
+static float4 RT1;
+static float4 RT2;
+static float4 RT3;
+
+struct SPIRV_Cross_Output
+{
+    float4 RT0 : SV_Target0;
+    float4 RT1 : SV_Target1;
+    float4 RT2 : SV_Target2;
+    float4 RT3 : SV_Target3;
+};
+
+void frag_main()
+{
+    RT0 = float4(1.0f, 1.0f, 1.0f, 1.0f);
+    RT1 = float4(2.0f, 2.0f, 2.0f, 2.0f);
+    RT2 = float4(3.0f, 3.0f, 3.0f, 3.0f);
+    RT3 = float4(4.0f, 4.0f, 4.0f, 4.0f);
+}
+
+SPIRV_Cross_Output main()
+{
+    frag_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.RT0 = RT0;
+    stage_output.RT1 = RT1;
+    stage_output.RT2 = RT2;
+    stage_output.RT3 = RT3;
+    return stage_output;
+}

reference/shaders-hlsl/frag/no-return.frag

@@ -0,0 +1,8 @@
+void frag_main()
+{
+}
+
+void main()
+{
+    frag_main();
+}

reference/shaders-hlsl/frag/no-return2.frag

@@ -0,0 +1,17 @@
+static float4 vColor;
+
+struct SPIRV_Cross_Input
+{
+    float4 vColor : TEXCOORD0;
+};
+
+void frag_main()
+{
+    float4 v = vColor;
+}
+
+void main(SPIRV_Cross_Input stage_input)
+{
+    vColor = stage_input.vColor;
+    frag_main();
+}

reference/shaders-hlsl/vert/basic.vert

@@ -7,23 +7,22 @@ cbuffer UBO
 {
     _UBO _16;
 };
-uniform float4 gl_HalfPixel;
 
 static float4 gl_Position;
 static float4 aVertex;
 static float3 vNormal;
 static float3 aNormal;
 
-struct InputVert
+struct SPIRV_Cross_Input
 {
     float3 aNormal : TEXCOORD0;
     float4 aVertex : TEXCOORD1;
 };
 
-struct OutputVert
+struct SPIRV_Cross_Output
 {
+    float4 gl_Position : SV_Position;
     float3 vNormal : TEXCOORD0;
-    float4 gl_Position : POSITION;
 };
 
 void vert_main()
@@ -32,15 +31,13 @@ void vert_main()
     vNormal = aNormal;
 }
 
-OutputVert main(InputVert input)
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
 {
-    aVertex = input.aVertex;
-    aNormal = input.aNormal;
+    aVertex = stage_input.aVertex;
+    aNormal = stage_input.aNormal;
     vert_main();
-    OutputVert output;
-    output.gl_Position = gl_Position;
-    output.vNormal = vNormal;
-    output.gl_Position.x = output.gl_Position.x - gl_HalfPixel.x * output.gl_Position.w;
-    output.gl_Position.y = output.gl_Position.y + gl_HalfPixel.y * output.gl_Position.w;
-    return output;
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    stage_output.vNormal = vNormal;
+    return stage_output;
 }

reference/shaders-hlsl/vert/instancing.vert

@@ -0,0 +1,29 @@
+static float4 gl_Position;
+static int gl_VertexIndex;
+static int gl_InstanceIndex;
+struct SPIRV_Cross_Input
+{
+    uint gl_VertexIndex : SV_VertexID;
+    uint gl_InstanceIndex : SV_InstanceID;
+};
+
+struct SPIRV_Cross_Output
+{
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    float _19 = float(gl_VertexIndex + gl_InstanceIndex);
+    gl_Position = float4(_19, _19, _19, _19);
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    gl_VertexIndex = int(stage_input.gl_VertexIndex);
+    gl_InstanceIndex = int(stage_input.gl_InstanceIndex);
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    return stage_output;
+}

reference/shaders-hlsl/vert/locations.vert

@@ -0,0 +1,75 @@
+struct Foo
+{
+    float3 a;
+    float3 b;
+    float3 c;
+};
+
+static float4 gl_Position;
+static float4 Input2;
+static float4 Input4;
+static float4 Input0;
+static float vLocation0;
+static float vLocation1;
+static float vLocation2[2];
+static Foo vLocation4;
+static float vLocation9;
+
+struct VertexOut
+{
+    float3 color : TEXCOORD7;
+    float3 foo : TEXCOORD8;
+};
+
+static VertexOut vout;
+
+struct SPIRV_Cross_Input
+{
+    float4 Input2 : TEXCOORD2;
+    float4 Input4 : TEXCOORD4;
+    float4 Input0 : TEXCOORD0;
+};
+
+struct SPIRV_Cross_Output
+{
+    float4 gl_Position : SV_Position;
+    float vLocation0 : TEXCOORD0;
+    float vLocation1 : TEXCOORD1;
+    float vLocation2[2] : TEXCOORD2;
+    Foo vLocation4 : TEXCOORD4;
+    float vLocation9 : TEXCOORD9;
+};
+
+void vert_main()
+{
+    gl_Position = ((float4(1.0f, 1.0f, 1.0f, 1.0f) + Input2) + Input4) + Input0;
+    vLocation0 = 0.0f;
+    vLocation1 = 1.0f;
+    vLocation2[0] = 2.0f;
+    vLocation2[1] = 2.0f;
+    Foo foo;
+    foo.a = float3(1.0f, 1.0f, 1.0f);
+    foo.b = float3(1.0f, 1.0f, 1.0f);
+    foo.c = float3(1.0f, 1.0f, 1.0f);
+    vLocation4 = foo;
+    vLocation9 = 9.0f;
+    vout.color = float3(2.0f, 2.0f, 2.0f);
+    vout.foo = float3(4.0f, 4.0f, 4.0f);
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input, out VertexOut stage_outputvout)
+{
+    Input2 = stage_input.Input2;
+    Input4 = stage_input.Input4;
+    Input0 = stage_input.Input0;
+    vert_main();
+    stage_outputvout = vout;
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    stage_output.vLocation0 = vLocation0;
+    stage_output.vLocation1 = vLocation1;
+    stage_output.vLocation2 = vLocation2;
+    stage_output.vLocation4 = vLocation4;
+    stage_output.vLocation9 = vLocation9;
+    return stage_output;
+}

reference/shaders-hlsl/vert/no-input.vert

@@ -0,0 +1,18 @@
+static float4 gl_Position;
+struct SPIRV_Cross_Output
+{
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = float4(1.0f, 1.0f, 1.0f, 1.0f);
+}
+
+SPIRV_Cross_Output main()
+{
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    return stage_output;
+}

reference/shaders-hlsl/vert/qualifiers.vert

@@ -0,0 +1,50 @@
+static float4 gl_Position;
+static float vFlat;
+static float vCentroid;
+static float vSample;
+static float vNoperspective;
+
+struct Block
+{
+    nointerpolation float vFlat : TEXCOORD4;
+    centroid float vCentroid : TEXCOORD5;
+    sample float vSample : TEXCOORD6;
+    noperspective float vNoperspective : TEXCOORD7;
+};
+
+static Block vout;
+
+struct SPIRV_Cross_Output
+{
+    float4 gl_Position : SV_Position;
+    nointerpolation float vFlat : TEXCOORD0;
+    centroid float vCentroid : TEXCOORD1;
+    sample float vSample : TEXCOORD2;
+    noperspective float vNoperspective : TEXCOORD3;
+};
+
+void vert_main()
+{
+    gl_Position = float4(1.0f, 1.0f, 1.0f, 1.0f);
+    vFlat = 0.0f;
+    vCentroid = 1.0f;
+    vSample = 2.0f;
+    vNoperspective = 3.0f;
+    vout.vFlat = 0.0f;
+    vout.vCentroid = 1.0f;
+    vout.vSample = 2.0f;
+    vout.vNoperspective = 3.0f;
+}
+
+SPIRV_Cross_Output main(out Block stage_outputvout)
+{
+    vert_main();
+    stage_outputvout = vout;
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    stage_output.vFlat = vFlat;
+    stage_output.vCentroid = vCentroid;
+    stage_output.vSample = vSample;
+    stage_output.vNoperspective = vNoperspective;
+    return stage_output;
+}

shaders-hlsl/frag/builtins.frag

@@ -0,0 +1,11 @@
+#version 310 es
+precision mediump float;
+
+layout(location = 0) out vec4 FragColor;
+layout(location = 0) in vec4 vColor;
+
+void main()
+{
+	FragColor = gl_FragCoord + vColor;
+	gl_FragDepth = 0.5;
+}

shaders-hlsl/frag/io-block.frag

@@ -0,0 +1,16 @@
+#version 310 es
+#extension GL_EXT_shader_io_blocks : require
+precision mediump float;
+
+layout(location = 1) in VertexOut
+{
+	vec4 a;
+	vec4 b;
+};
+
+layout(location = 0) out vec4 FragColor;
+
+void main()
+{
+	FragColor = a + b;
+}

shaders-hlsl/frag/mrt.frag

@@ -0,0 +1,15 @@
+#version 310 es
+precision mediump float;
+
+layout(location = 0) out vec4 RT0;
+layout(location = 1) out vec4 RT1;
+layout(location = 2) out vec4 RT2;
+layout(location = 3) out vec4 RT3;
+
+void main()
+{
+	RT0 = vec4(1.0);
+	RT1 = vec4(2.0);
+	RT2 = vec4(3.0);
+	RT3 = vec4(4.0);
+}

shaders-hlsl/frag/no-return.frag

@@ -0,0 +1,5 @@
+#version 310 es
+
+void main()
+{
+}

shaders-hlsl/frag/no-return2.frag

@@ -0,0 +1,9 @@
+#version 310 es
+precision mediump float;
+
+layout(location = 0) in vec4 vColor;
+
+void main()
+{
+	vec4 v = vColor;
+}

shaders-hlsl/vert/instancing.vert

@@ -0,0 +1,6 @@
+#version 310 es
+
+void main()
+{
+	gl_Position = vec4(float(gl_VertexIndex + gl_InstanceIndex));
+}

shaders-hlsl/vert/locations.vert

@@ -0,0 +1,51 @@
+#version 310 es
+#extension GL_EXT_shader_io_blocks : require
+
+struct Foo
+{
+	vec3 a;
+	vec3 b;
+	vec3 c;
+};
+
+// This will lock to input location 2.
+layout(location = 2) in vec4 Input2;
+// This will lock to input location 4.
+layout(location = 4) in vec4 Input4;
+// This will pick first available, which is 0.
+in vec4 Input0;
+
+// Locks output 0.
+layout(location = 0) out float vLocation0;
+// Locks output 1.
+layout(location = 1) out float vLocation1;
+// Picks first available two locations, so, 2 and 3.
+out float vLocation2[2];
+// Picks first available location, 4.
+out Foo vLocation4;
+// Picks first available location 9.
+out float vLocation9;
+
+// Locks location 7 and 8.
+layout(location = 7) out VertexOut
+{
+	vec3 color;
+	vec3 foo;
+} vout;
+
+void main()
+{
+	gl_Position = vec4(1.0) + Input2 + Input4 + Input0;
+	vLocation0 = 0.0;
+	vLocation1 = 1.0;
+	vLocation2[0] = 2.0;
+	vLocation2[1] = 2.0;
+	Foo foo;
+	foo.a = vec3(1.0);
+	foo.b = vec3(1.0);
+	foo.c = vec3(1.0);
+	vLocation4 = foo;
+	vLocation9 = 9.0;
+	vout.color = vec3(2.0);
+	vout.foo = vec3(4.0);
+}

shaders-hlsl/vert/no-input.vert

@@ -0,0 +1,6 @@
+#version 310 es
+
+void main()
+{
+	gl_Position = vec4(1.0);
+}

shaders-hlsl/vert/qualifiers.vert

@@ -0,0 +1,27 @@
+#version 450
+
+layout(location = 0) flat out float vFlat;
+layout(location = 1) centroid out float vCentroid;
+layout(location = 2) sample out float vSample;
+layout(location = 3) noperspective out float vNoperspective;
+
+layout(location = 4) out Block
+{
+	flat float vFlat;
+	centroid float vCentroid;
+	sample float vSample;
+	noperspective float vNoperspective;
+} vout;
+
+void main()
+{
+	gl_Position = vec4(1.0);
+	vFlat = 0.0;
+	vCentroid = 1.0;
+	vSample = 2.0;
+	vNoperspective = 3.0;
+	vout.vFlat = 0.0;
+	vout.vCentroid = 1.0;
+	vout.vSample = 2.0;
+	vout.vNoperspective = 3.0;
+}

spirv_cpp.cpp

@@ -297,6 +297,8 @@ string CompilerCPP::compile()
 	backend.explicit_struct_type = true;
 	backend.use_initializer_list = true;
 
+	update_active_builtins();
+
 	uint32_t pass_count = 0;
 	do
 	{

spirv_cross.cpp

@@ -136,7 +136,7 @@ bool Compiler::block_is_pure(const SPIRBlock &block)
 	return true;
 }
 
-string Compiler::to_name(uint32_t id, bool allow_alias)
+string Compiler::to_name(uint32_t id, bool allow_alias) const
 {
 	if (allow_alias && ids.at(id).get_type() == TypeType)
 	{
@@ -491,7 +491,7 @@ bool Compiler::InterfaceVariableAccessHandler::handle(Op opcode, const uint32_t
 
 	case OpCopyMemory:
 	{
-		if (length < 3)
+		if (length < 2)
 			return false;
 
 		auto *var = compiler.maybe_get<SPIRVariable>(args[0]);
@@ -2865,7 +2865,7 @@ void Compiler::analyze_variable_scope(SPIRFunction &entry)
 
 			case OpCopyMemory:
 			{
-				if (length < 3)
+				if (length < 2)
 					return false;
 
 				uint32_t lhs = args[0];
@@ -3116,3 +3116,126 @@ bool Compiler::get_common_basic_type(const SPIRType &type, SPIRType::BaseType &b
 		return true;
 	}
 }
+
+bool Compiler::ActiveBuiltinHandler::handle(spv::Op opcode, const uint32_t *args, uint32_t length)
+{
+	const auto add_if_builtin = [&](uint32_t id) {
+		// Only handles variables here.
+		// Builtins which are part of a block are handled in AccessChain.
+		auto *var = compiler.maybe_get<SPIRVariable>(id);
+		if (var && compiler.meta[id].decoration.builtin)
+		{
+			auto &type = compiler.get<SPIRType>(var->basetype);
+			auto &flags =
+			    type.storage == StorageClassInput ? compiler.active_input_builtins : compiler.active_output_builtins;
+			flags |= 1ull << compiler.meta[id].decoration.builtin_type;
+		}
+	};
+
+	switch (opcode)
+	{
+	case OpStore:
+		if (length < 1)
+			return false;
+
+		add_if_builtin(args[0]);
+		break;
+
+	case OpCopyMemory:
+		if (length < 2)
+			return false;
+
+		add_if_builtin(args[0]);
+		add_if_builtin(args[1]);
+		break;
+
+	case OpCopyObject:
+	case OpLoad:
+		if (length < 3)
+			return false;
+
+		add_if_builtin(args[2]);
+		break;
+
+	case OpFunctionCall:
+	{
+		if (length < 3)
+			return false;
+
+		uint32_t count = length - 3;
+		args += 3;
+		for (uint32_t i = 0; i < count; i++)
+			add_if_builtin(args[i]);
+		break;
+	}
+
+	case OpAccessChain:
+	case OpInBoundsAccessChain:
+	{
+		if (length < 4)
+			return false;
+
+		// Only consider global variables, cannot consider variables in functions yet, or other
+		// access chains as they have not been created yet.
+		auto *var = compiler.maybe_get<SPIRVariable>(args[2]);
+		if (!var)
+			break;
+
+		auto *type = &compiler.get<SPIRType>(var->basetype);
+
+		// Start traversing type hierarchy at the proper non-pointer types.
+		while (type->pointer)
+		{
+			assert(type->parent_type);
+			type = &compiler.get<SPIRType>(type->parent_type);
+		}
+
+		auto &flags =
+		    type->storage == StorageClassInput ? compiler.active_input_builtins : compiler.active_output_builtins;
+
+		uint32_t count = length - 3;
+		args += 3;
+		for (uint32_t i = 0; i < count; i++)
+		{
+			// Arrays
+			if (!type->array.empty())
+			{
+				type = &compiler.get<SPIRType>(type->parent_type);
+			}
+			// Structs
+			else if (type->basetype == SPIRType::Struct)
+			{
+				uint32_t index = compiler.get<SPIRConstant>(args[i]).scalar();
+
+				if (index < uint32_t(compiler.meta[type->self].members.size()))
+				{
+					auto &decorations = compiler.meta[type->self].members[index];
+					if (decorations.builtin)
+						flags |= 1ull << decorations.builtin_type;
+				}
+
+				type = &compiler.get<SPIRType>(type->member_types[index]);
+			}
+			else
+			{
+				// No point in traversing further. We won't find any extra builtins.
+				break;
+			}
+		}
+		break;
+	}
+
+	default:
+		break;
+	}
+
+	return true;
+}
+
+void Compiler::update_active_builtins()
+{
+	active_input_builtins = 0;
+	active_output_builtins = 0;
+	ActiveBuiltinHandler handler(*this);
+	traverse_all_reachable_opcodes(get<SPIRFunction>(entry_point), handler);
+}

spirv_cross.hpp

@@ -411,7 +411,7 @@ protected:
 	std::unordered_set<uint32_t> selection_merge_targets;
 	std::unordered_set<uint32_t> multiselect_merge_targets;
 
-	virtual std::string to_name(uint32_t id, bool allow_alias = true);
+	virtual std::string to_name(uint32_t id, bool allow_alias = true) const;
 	bool is_builtin_variable(const SPIRVariable &var) const;
 	bool is_hidden_variable(const SPIRVariable &var, bool include_builtins = false) const;
 	bool is_immutable(uint32_t id) const;
@@ -577,6 +577,17 @@ protected:
 		void register_combined_image_sampler(SPIRFunction &caller, uint32_t texture_id, uint32_t sampler_id);
 	};
 
+	struct ActiveBuiltinHandler : OpcodeHandler
+	{
+		ActiveBuiltinHandler(Compiler &compiler_)
+		    : compiler(compiler_)
+		{
+		}
+
+		bool handle(spv::Op opcode, const uint32_t *args, uint32_t length) override;
+		Compiler &compiler;
+	};
+
 	bool traverse_all_reachable_opcodes(const SPIRBlock &block, OpcodeHandler &handler) const;
 	bool traverse_all_reachable_opcodes(const SPIRFunction &block, OpcodeHandler &handler) const;
 	// This must be an ordered data structure so we always pick the same type aliases.
@@ -591,6 +602,11 @@ protected:
 
 	std::unordered_set<uint32_t> forced_temporaries;
 	std::unordered_set<uint32_t> forwarded_temporaries;
+
+	uint64_t active_input_builtins = 0;
+	uint64_t active_output_builtins = 0;
+	// Traverses all reachable opcodes and sets active_builtins to a bitmask of all builtin variables which are accessed in the shader.
+	void update_active_builtins();
 };
 }
 

spirv_glsl.cpp

@@ -310,6 +310,7 @@ string CompilerGLSL::compile()
 	// Scan the SPIR-V to find trivial uses of extensions.
 	find_static_extensions();
 	fixup_image_load_store_access();
+	update_active_builtins();
 
 	uint32_t pass_count = 0;
 	do
@@ -3331,8 +3332,12 @@ string CompilerGLSL::access_chain_internal(uint32_t base, const uint32_t *indice
 
 	const auto *type = &expression_type(base);
 
-	// For resolving array accesses, etc, keep a local copy for poking.
-	SPIRType temp;
+	// Start traversing type hierarchy at the proper non-pointer types.
+	while (type->pointer)
+	{
+		assert(type->parent_type);
+		type = &get<SPIRType>(type->parent_type);
+	}
 
 	bool access_chain_is_arrayed = false;
 	bool row_major_matrix_needs_conversion = is_non_native_row_major_matrix(base);
@@ -3351,11 +3356,8 @@ string CompilerGLSL::access_chain_internal(uint32_t base, const uint32_t *indice
 				expr += to_expression(index);
 			expr += "]";
 
-			// We have to modify the type, so keep a local copy.
-			if (&temp != type)
-				temp = *type;
-			type = &temp;
-			temp.array.pop_back();
+			assert(type->parent_type);
+			type = &get<SPIRType>(type->parent_type);
 
 			access_chain_is_arrayed = true;
 		}
@@ -3414,11 +3416,7 @@ string CompilerGLSL::access_chain_internal(uint32_t base, const uint32_t *indice
 				expr += to_expression(index);
 			expr += "]";
 
-			// We have to modify the type, so keep a local copy.
-			if (&temp != type)
-				temp = *type;
-			type = &temp;
-			temp.columns = 1;
+			type = &get<SPIRType>(type->parent_type);
 		}
 		// Vector -> Scalar
 		else if (type->vecsize > 1)
@@ -3441,11 +3439,7 @@ string CompilerGLSL::access_chain_internal(uint32_t base, const uint32_t *indice
 				expr += "]";
 			}
 
-			// We have to modify the type, so keep a local copy.
-			if (&temp != type)
-				temp = *type;
-			type = &temp;
-			temp.vecsize = 1;
+			type = &get<SPIRType>(type->parent_type);
 		}
 		else
 			SPIRV_CROSS_THROW("Cannot subdivide a scalar value!");
@@ -3686,6 +3680,13 @@ std::pair<std::string, uint32_t> CompilerGLSL::flattened_access_chain_offset(uin
 {
 	const auto *type = &expression_type(base);
 
+	// Start traversing type hierarchy at the proper non-pointer types.
+	while (type->pointer)
+	{
+		assert(type->parent_type);
+		type = &get<SPIRType>(type->parent_type);
+	}
+
 	// This holds the type of the current pointer which we are traversing through.
 	// We always start out from a struct type which is the block.
 	// This is primarily used to reflect the array strides and matrix strides later.

spirv_glsl.hpp

@@ -357,8 +357,8 @@ protected:
 	virtual const char *to_storage_qualifiers_glsl(const SPIRVariable &var);
 	const char *flags_to_precision_qualifiers_glsl(const SPIRType &type, uint64_t flags);
 	const char *format_to_glsl(spv::ImageFormat format);
-	std::string layout_for_member(const SPIRType &type, uint32_t index);
-	std::string to_interpolation_qualifiers(uint64_t flags);
+	virtual std::string layout_for_member(const SPIRType &type, uint32_t index);
+	virtual std::string to_interpolation_qualifiers(uint64_t flags);
 	uint64_t combined_decoration_for_member(const SPIRType &type, uint32_t index);
 	std::string layout_for_variable(const SPIRVariable &variable);
 	std::string to_combined_image_sampler(uint32_t image_id, uint32_t samp_id);

spirv_hlsl.cpp

@@ -22,24 +22,6 @@ using namespace spv;
 using namespace spirv_cross;
 using namespace std;
 
-namespace
-{
-struct VariableComparator
-{
-	VariableComparator(const std::vector<Meta> &m)
-	    : meta(m)
-	{
-	}
-
-	bool operator()(SPIRVariable *var1, SPIRVariable *var2)
-	{
-		return meta[var1->self].decoration.alias.compare(meta[var2->self].decoration.alias) < 0;
-	}
-
-	const std::vector<Meta> &meta;
-};
-}
-
 string CompilerHLSL::type_to_glsl(const SPIRType &type)
 {
 	// Ignore the pointer type since GLSL doesn't have pointers.
@@ -148,21 +130,15 @@ void CompilerHLSL::emit_header()
 
 void CompilerHLSL::emit_interface_block_globally(const SPIRVariable &var)
 {
-	auto &execution = get_entry_point();
-
 	add_resource_name(var.self);
 
-	if (execution.model == ExecutionModelVertex && var.storage == StorageClassInput && is_builtin_variable(var))
-	{
-	}
-	else if (execution.model == ExecutionModelVertex && var.storage == StorageClassOutput && is_builtin_variable(var))
-	{
-		statement("static float4 gl_Position;");
-	}
-	else
-	{
-		statement("static ", variable_decl(var), ";");
-	}
+	// The global copies of I/O variables should not contain interpolation qualifiers.
+	// These are emitted inside the interface structs.
+	auto &flags = meta[var.self].decoration.decoration_flags;
+	auto old_flags = flags;
+	flags = 0;
+	statement("static ", variable_decl(var), ";");
+	flags = old_flags;
 }
 
 const char *CompilerHLSL::to_storage_qualifiers_glsl(const SPIRVariable &var)
@@ -178,71 +154,257 @@ const char *CompilerHLSL::to_storage_qualifiers_glsl(const SPIRVariable &var)
 	return "";
 }
 
-void CompilerHLSL::emit_interface_block_in_struct(const SPIRVariable &var, uint32_t &binding_number, bool builtins)
+void CompilerHLSL::emit_builtin_outputs_in_struct()
+{
+	bool legacy = options.shader_model <= 30;
+	for (uint32_t i = 0; i < 64; i++)
+	{
+		if (!(active_output_builtins & (1ull << i)))
+			continue;
+
+		const char *type = nullptr;
+		const char *semantic = nullptr;
+		auto builtin = static_cast<BuiltIn>(i);
+		switch (builtin)
+		{
+		case BuiltInPosition:
+			type = "float4";
+			semantic = legacy ? "POSITION" : "SV_Position";
+			break;
+
+		case BuiltInFragDepth:
+			type = "float";
+			semantic = legacy ? "DEPTH" : "SV_Depth";
+			break;
+
+		default:
+			SPIRV_CROSS_THROW("Unsupported builtin in HLSL.");
+			break;
+		}
+
+		if (type && semantic)
+			statement(type, " ", builtin_to_glsl(builtin), " : ", semantic, ";");
+	}
+}
+
+void CompilerHLSL::emit_builtin_inputs_in_struct()
+{
+	bool legacy = options.shader_model <= 30;
+	for (uint32_t i = 0; i < 64; i++)
+	{
+		if (!(active_input_builtins & (1ull << i)))
+			continue;
+
+		const char *type = nullptr;
+		const char *semantic = nullptr;
+		auto builtin = static_cast<BuiltIn>(i);
+		switch (builtin)
+		{
+		case BuiltInFragCoord:
+			type = "float4";
+			semantic = legacy ? "VPOS" : "SV_Position";
+			break;
+
+		case BuiltInVertexIndex:
+			if (legacy)
+				SPIRV_CROSS_THROW("Vertex index not supported in SM 3.0 or lower.");
+			type = "uint";
+			semantic = "SV_VertexID";
+			break;
+
+		case BuiltInInstanceIndex:
+			if (legacy)
+				SPIRV_CROSS_THROW("Instance index not supported in SM 3.0 or lower.");
+			type = "uint";
+			semantic = "SV_InstanceID";
+			break;
+
+		default:
+			SPIRV_CROSS_THROW("Unsupported builtin in HLSL.");
+			break;
+		}
+
+		if (type && semantic)
+			statement(type, " ", builtin_to_glsl(builtin), " : ", semantic, ";");
+	}
+}
+
+uint32_t CompilerHLSL::type_to_consumed_locations(const SPIRType &type) const
+{
+	// TODO: Need to verify correctness.
+	uint32_t elements = 0;
+
+	if (type.basetype == SPIRType::Struct)
+	{
+		for (uint32_t i = 0; i < uint32_t(type.member_types.size()); i++)
+			elements += type_to_consumed_locations(get<SPIRType>(type.member_types[i]));
+	}
+	else
+	{
+		uint32_t array_multiplier = 1;
+		for (uint32_t i = 0; i < uint32_t(type.array.size()); i++)
+		{
+			if (type.array_size_literal[i])
+				array_multiplier *= type.array[i];
+			else
+				array_multiplier *= get<SPIRConstant>(type.array[i]).scalar();
+		}
+		elements += array_multiplier * type.columns;
+	}
+	return elements;
+}
+
+string CompilerHLSL::to_interpolation_qualifiers(uint64_t flags)
+{
+	string res;
+	//if (flags & (1ull << DecorationSmooth))
+	//    res += "linear ";
+	if (flags & (1ull << DecorationFlat))
+		res += "nointerpolation ";
+	if (flags & (1ull << DecorationNoPerspective))
+		res += "noperspective ";
+	if (flags & (1ull << DecorationCentroid))
+		res += "centroid ";
+	if (flags & (1ull << DecorationPatch))
+		res += "patch "; // Seems to be different in actual HLSL.
+	if (flags & (1ull << DecorationSample))
+		res += "sample ";
+	if (flags & (1ull << DecorationInvariant))
+		res += "invariant "; // Not supported?
+
+	return res;
+}
+
+void CompilerHLSL::emit_io_block(const SPIRVariable &var)
+{
+	auto &type = get<SPIRType>(var.basetype);
+	add_resource_name(type.self);
+
+	statement("struct ", to_name(type.self));
+	begin_scope();
+	type.member_name_cache.clear();
+
+	for (uint32_t i = 0; i < uint32_t(type.member_types.size()); i++)
+	{
+		string semantic;
+		if (has_member_decoration(type.self, i, DecorationLocation))
+		{
+			uint32_t location = get_member_decoration(type.self, i, DecorationLocation);
+			semantic = join(" : TEXCOORD", location);
+		}
+
+		add_member_name(type, i);
+
+		auto &membertype = get<SPIRType>(type.member_types[i]);
+		statement(to_interpolation_qualifiers(get_member_decoration_mask(type.self, i)),
+		          variable_decl(membertype, to_member_name(type, i)), semantic, ";");
+	}
+
+	end_scope_decl();
+	statement("");
+
+	statement("static ", variable_decl(var), ";");
+	statement("");
+}
+
+void CompilerHLSL::emit_interface_block_in_struct(const SPIRVariable &var, unordered_set<uint32_t> &active_locations)
 {
 	auto &execution = get_entry_point();
 	auto &type = get<SPIRType>(var.basetype);
 
-	const char *binding = "TEXCOORD";
+	string binding;
 	bool use_binding_number = true;
+	bool legacy = options.shader_model <= 30;
 	if (execution.model == ExecutionModelFragment && var.storage == StorageClassOutput)
 	{
-		binding = "COLOR";
+		binding = join(legacy ? "COLOR" : "SV_Target", get_decoration(var.self, DecorationLocation));
 		use_binding_number = false;
 	}
-	else if (execution.model == ExecutionModelVertex && var.storage == StorageClassOutput && is_builtin_variable(var))
+
+	const auto get_vacant_location = [&]() -> uint32_t {
+		for (uint32_t i = 0; i < 64; i++)
+			if (!active_locations.count(i))
+				return i;
+		SPIRV_CROSS_THROW("All locations from 0 to 63 are exhausted.");
+	};
+
+	auto &m = meta[var.self].decoration;
+	auto name = to_name(var.self);
+	if (use_binding_number)
 	{
-		if (options.shader_model <= 30)
-		{
-			binding = "POSITION";
-		}
+		uint32_t binding_number;
+
+		// If an explicit location exists, use it with TEXCOORD[N] semantic.
+		// Otherwise, pick a vacant location.
+		if (m.decoration_flags & (1ull << DecorationLocation))
+			binding_number = m.location;
 		else
-		{
-			binding = "SV_POSITION";
-		}
-		use_binding_number = false;
-	}
+			binding_number = get_vacant_location();
 
-	bool is_no_builtin = !is_builtin_variable(var) && !var.remapped_variable;
-
-	if ((is_no_builtin && !builtins) || (!is_no_builtin && builtins))
-	{
-		auto &m = meta[var.self].decoration;
-		if (use_binding_number)
+		if (type.columns > 1)
 		{
-			if (type.vecsize == 4 && type.columns == 4)
+			if (!type.array.empty())
+				SPIRV_CROSS_THROW("Arrays of matrices used as input/output. This is not supported.");
+
+			// Unroll matrices.
+			for (uint32_t i = 0; i < type.columns; i++)
 			{
-				for (int i = 0; i < 4; ++i)
-				{
-					std::stringstream name;
-					name << m.alias << "_" << i;
-					SPIRType newtype = type;
-					newtype.columns = 1;
-					statement(variable_decl(newtype, name.str()), " : ", binding, binding_number++, ";");
-				}
-				--binding_number;
-			}
-			else
-			{
-				statement(variable_decl(type, m.alias), " : ", binding, binding_number, ";");
+				SPIRType newtype = type;
+				newtype.columns = 1;
+				statement(to_interpolation_qualifiers(get_decoration_mask(var.self)),
+				          variable_decl(newtype, join(name, "_", i)), " : TEXCOORD", binding_number, ";");
+				active_locations.insert(binding_number++);
 			}
 		}
 		else
 		{
-			if (execution.model == ExecutionModelVertex)
-			{
-				statement("float4 gl_Position", " : ", binding, ";");
-			}
-			else
-			{
-				statement(variable_decl(type, m.alias), " : ", binding, ";");
-			}
+			statement(to_interpolation_qualifiers(get_decoration_mask(var.self)), variable_decl(type, name),
+			          " : TEXCOORD", binding_number, ";");
+
+			// Structs and arrays should consume more locations.
+			uint32_t consumed_locations = type_to_consumed_locations(type);
+			for (uint32_t i = 0; i < consumed_locations; i++)
+				active_locations.insert(binding_number + i);
 		}
 	}
+	else
+		statement(variable_decl(type, name), " : ", binding, ";");
+}
 
-	if (is_no_builtin)
+void CompilerHLSL::emit_builtin_variables()
+{
+	// Emit global variables for the interface variables which are statically used by the shader.
+	for (uint32_t i = 0; i < 64; i++)
 	{
-		++binding_number;
+		if (!((active_input_builtins | active_output_builtins) & (1ull << i)))
+			continue;
+
+		const char *type = nullptr;
+		auto builtin = static_cast<BuiltIn>(i);
+
+		switch (builtin)
+		{
+		case BuiltInFragCoord:
+		case BuiltInPosition:
+			type = "float4";
+			break;
+
+		case BuiltInFragDepth:
+			type = "float";
+			break;
+
+		case BuiltInVertexIndex:
+		case BuiltInInstanceIndex:
+			type = "int";
+			break;
+
+		default:
+			SPIRV_CROSS_THROW(join("Unsupported builtin in HLSL: ", unsigned(builtin)));
+			break;
+		}
+
+		if (type)
+			statement("static ", type, " ", builtin_to_glsl(builtin), ";");
 	}
 }
 
@@ -250,10 +412,6 @@ void CompilerHLSL::emit_resources()
 {
 	auto &execution = get_entry_point();
 
-	// Emit PLS blocks if we have such variables.
-	if (!pls_inputs.empty() || !pls_outputs.empty())
-		emit_pls();
-
 	// Output all basic struct types which are not Block or BufferBlock as these are declared inplace
 	// when such variables are instantiated.
 	for (auto &id : ids)
@@ -334,17 +492,25 @@ void CompilerHLSL::emit_resources()
 		statement("");
 	emitted = false;
 
+	// Emit builtin input and output variables here.
+	emit_builtin_variables();
+
 	for (auto &id : ids)
 	{
 		if (id.get_type() == TypeVariable)
 		{
 			auto &var = id.get<SPIRVariable>();
 			auto &type = get<SPIRType>(var.basetype);
+			bool block = (meta[type.self].decoration.decoration_flags & (1ull << DecorationBlock)) != 0;
 
-			if (var.storage != StorageClassFunction && !var.remapped_variable && type.pointer &&
-			    (var.storage == StorageClassInput || var.storage == StorageClassOutput) &&
+			// Do not emit I/O blocks here.
+			// I/O blocks can be arrayed, so we must deal with them separately to support geometry shaders
+			// and tessellation down the line.
+			if (!block && var.storage != StorageClassFunction && !var.remapped_variable && type.pointer &&
+			    (var.storage == StorageClassInput || var.storage == StorageClassOutput) && !is_builtin_variable(var) &&
 			    interface_variable_exists_in_entry_point(var.self))
 			{
+				// Only emit non-builtins which are not blocks here. Builtin variables are handled separately.
 				emit_interface_block_globally(var);
 				emitted = true;
 			}
@@ -355,81 +521,114 @@ void CompilerHLSL::emit_resources()
 		statement("");
 	emitted = false;
 
-	if (execution.model == ExecutionModelVertex)
-	{
-		statement("struct InputVert");
-	}
-	else
-	{
-		statement("struct InputFrag");
-	}
-	begin_scope();
-	uint32_t binding_number = 0;
-	std::vector<SPIRVariable *> variables;
+	require_input = false;
+	require_output = false;
+	unordered_set<uint32_t> active_inputs;
+	unordered_set<uint32_t> active_outputs;
+	vector<SPIRVariable *> input_variables;
+	vector<SPIRVariable *> output_variables;
 	for (auto &id : ids)
 	{
 		if (id.get_type() == TypeVariable)
 		{
 			auto &var = id.get<SPIRVariable>();
 			auto &type = get<SPIRType>(var.basetype);
+			bool block = (meta[type.self].decoration.decoration_flags & (1ull << DecorationBlock)) != 0;
 
-			if (var.storage != StorageClassFunction && !var.remapped_variable && type.pointer &&
-			    var.storage == StorageClassInput && interface_variable_exists_in_entry_point(var.self))
+			if (var.storage != StorageClassInput && var.storage != StorageClassOutput)
+				continue;
+
+			// Do not emit I/O blocks here.
+			// I/O blocks can be arrayed, so we must deal with them separately to support geometry shaders
+			// and tessellation down the line.
+			if (!block && !var.remapped_variable && type.pointer && !is_builtin_variable(var) &&
+			    interface_variable_exists_in_entry_point(var.self))
 			{
-				if (execution.model == ExecutionModelVertex && is_builtin_variable(var))
-					continue;
-				variables.push_back(&var);
+				if (var.storage == StorageClassInput)
+					input_variables.push_back(&var);
+				else
+					output_variables.push_back(&var);
+			}
+
+			// Reserve input and output locations for block variables as necessary.
+			if (block && !is_builtin_variable(var) && interface_variable_exists_in_entry_point(var.self))
+			{
+				auto &active = var.storage == StorageClassInput ? active_inputs : active_outputs;
+				for (uint32_t i = 0; i < uint32_t(type.member_types.size()); i++)
+				{
+					if (has_member_decoration(type.self, i, DecorationLocation))
+					{
+						uint32_t location = get_member_decoration(type.self, i, DecorationLocation);
+						active.insert(location);
+					}
+				}
+
+				// Emit the block struct and a global variable here.
+				emit_io_block(var);
 			}
 		}
 	}
-	sort(variables.begin(), variables.end(), VariableComparator(meta));
-	for (auto var : variables)
-	{
-		emit_interface_block_in_struct(*var, binding_number, false);
-	}
-	for (auto var : variables)
-	{
-		emit_interface_block_in_struct(*var, binding_number, true);
-	}
-	end_scope_decl();
-	statement("");
 
-	if (execution.model == ExecutionModelVertex)
-	{
-		statement("struct OutputVert");
-	}
-	else
-	{
-		statement("struct OutputFrag");
-	}
-	begin_scope();
-	binding_number = 0;
-	variables.clear();
-	for (auto &id : ids)
-	{
-		if (id.get_type() == TypeVariable)
+	const auto variable_compare = [&](const SPIRVariable *a, const SPIRVariable *b) -> bool {
+		// Sort input and output variables based on, from more robust to less robust:
+		// - Location
+		// - Variable has a location
+		// - Name comparison
+		// - Variable has a name
+		// - Fallback: ID
+		bool has_location_a = has_decoration(a->self, DecorationLocation);
+		bool has_location_b = has_decoration(b->self, DecorationLocation);
+
+		if (has_location_a && has_location_b)
 		{
-			auto &var = id.get<SPIRVariable>();
-			auto &type = get<SPIRType>(var.basetype);
-
-			if (var.storage != StorageClassFunction && !var.remapped_variable && type.pointer &&
-			    var.storage == StorageClassOutput && interface_variable_exists_in_entry_point(var.self))
-			{
-				variables.push_back(&var);
-			}
+			return get_decoration(a->self, DecorationLocation) < get_decoration(b->self, DecorationLocation);
 		}
-	}
-	sort(variables.begin(), variables.end(), VariableComparator(meta));
-	for (auto var : variables)
+		else if (has_location_a && !has_location_b)
+			return true;
+		else if (!has_location_a && has_location_b)
+			return false;
+
+		const auto &name1 = to_name(a->self);
+		const auto &name2 = to_name(b->self);
+
+		if (name1.empty() && name2.empty())
+			return a->self < b->self;
+		else if (name1.empty())
+			return true;
+		else if (name2.empty())
+			return false;
+
+		return name1.compare(name2) < 0;
+	};
+
+	if (!input_variables.empty() || active_input_builtins)
 	{
-		emit_interface_block_in_struct(*var, binding_number, false);
+		require_input = true;
+		statement("struct SPIRV_Cross_Input");
+
+		begin_scope();
+		sort(input_variables.begin(), input_variables.end(), variable_compare);
+		emit_builtin_inputs_in_struct();
+		for (auto var : input_variables)
+			emit_interface_block_in_struct(*var, active_inputs);
+		end_scope_decl();
+		statement("");
 	}
-	for (auto var : variables)
+
+	if (!output_variables.empty() || active_output_builtins)
 	{
-		emit_interface_block_in_struct(*var, binding_number, true);
+		require_output = true;
+		statement("struct SPIRV_Cross_Output");
+
+		begin_scope();
+		// FIXME: Use locations properly if they exist.
+		sort(output_variables.begin(), output_variables.end(), variable_compare);
+		emit_builtin_outputs_in_struct();
+		for (auto var : output_variables)
+			emit_interface_block_in_struct(*var, active_outputs);
+		end_scope_decl();
+		statement("");
 	}
-	end_scope_decl();
-	statement("");
 
 	// Global variables.
 	for (auto global : global_variables)
@@ -456,6 +655,11 @@ void CompilerHLSL::emit_resources()
 	}
 }
 
+string CompilerHLSL::layout_for_member(const SPIRType &, uint32_t)
+{
+	return "";
+}
+
 void CompilerHLSL::emit_buffer_block(const SPIRVariable &var)
 {
 	auto &type = get<SPIRType>(var.basetype);
@@ -541,97 +745,198 @@ void CompilerHLSL::emit_function_prototype(SPIRFunction &func, uint64_t return_f
 
 void CompilerHLSL::emit_hlsl_entry_point()
 {
-	auto &execution = get_entry_point();
-	const char *post = "Frag";
-	if (execution.model == ExecutionModelVertex)
-	{
-		post = "Vert";
-	}
+	vector<string> arguments;
 
-	statement("Output", post, " main(Input", post, " input)");
-	begin_scope();
+	if (require_input)
+		arguments.push_back("SPIRV_Cross_Input stage_input");
 
+	// Add I/O blocks as separate arguments with appropriate storage qualifier.
 	for (auto &id : ids)
 	{
 		if (id.get_type() == TypeVariable)
 		{
 			auto &var = id.get<SPIRVariable>();
 			auto &type = get<SPIRType>(var.basetype);
+			bool block = (meta[type.self].decoration.decoration_flags & (1ull << DecorationBlock)) != 0;
 
-			if (var.storage != StorageClassFunction && !var.remapped_variable && type.pointer &&
-			    var.storage == StorageClassInput && interface_variable_exists_in_entry_point(var.self))
+			if (var.storage != StorageClassInput && var.storage != StorageClassOutput)
+				continue;
+
+			if (block && !is_builtin_variable(var) && interface_variable_exists_in_entry_point(var.self))
 			{
-				if (execution.model == ExecutionModelVertex && is_builtin_variable(var))
-					continue;
-
-				auto &m = meta[var.self].decoration;
-				auto &mtype = get<SPIRType>(var.basetype);
-				if (mtype.vecsize == 4 && mtype.columns == 4)
+				if (var.storage == StorageClassInput)
 				{
-					statement(m.alias, "[0] = input.", m.alias, "_0;");
-					statement(m.alias, "[1] = input.", m.alias, "_1;");
-					statement(m.alias, "[2] = input.", m.alias, "_2;");
-					statement(m.alias, "[3] = input.", m.alias, "_3;");
+					arguments.push_back(join("in ", variable_decl(type, join("stage_input", to_name(var.self)))));
+				}
+				else if (var.storage == StorageClassOutput)
+				{
+					arguments.push_back(join("out ", variable_decl(type, join("stage_output", to_name(var.self)))));
+				}
+			}
+		}
+	}
+
+	auto &execution = get_entry_point();
+	statement(require_output ? "SPIRV_Cross_Output " : "void ", "main(", merge(arguments), ")");
+	begin_scope();
+	bool legacy = options.shader_model <= 30;
+
+	// Copy builtins from entry point arguments to globals.
+	for (uint32_t i = 0; i < 64; i++)
+	{
+		if (!(active_input_builtins & (1ull << i)))
+			continue;
+
+		auto builtin = builtin_to_glsl(static_cast<BuiltIn>(i));
+		switch (static_cast<BuiltIn>(i))
+		{
+		case BuiltInFragCoord:
+			// VPOS in D3D9 is sampled at integer locations, apply half-pixel offset to be consistent.
+			// TODO: Do we need an option here? Any reason why a D3D9 shader would be used
+			// on a D3D10+ system with a different rasterization config?
+			if (legacy)
+				statement(builtin, " = stage_input.", builtin, " + float4(0.5f, 0.5f, 0.0f, 0.0f);");
+			else
+				statement(builtin, " = stage_input.", builtin, ";");
+			break;
+
+		case BuiltInVertexIndex:
+		case BuiltInInstanceIndex:
+			// D3D semantics are uint, but shader wants int.
+			statement(builtin, " = int(stage_input.", builtin, ");");
+			break;
+
+		default:
+			statement(builtin, " = stage_input.", builtin, ";");
+			break;
+		}
+	}
+
+	// Copy from stage input struct to globals.
+	for (auto &id : ids)
+	{
+		if (id.get_type() == TypeVariable)
+		{
+			auto &var = id.get<SPIRVariable>();
+			auto &type = get<SPIRType>(var.basetype);
+			bool block = (meta[type.self].decoration.decoration_flags & (1ull << DecorationBlock)) != 0;
+
+			if (var.storage != StorageClassInput)
+				continue;
+
+			if (!block && !var.remapped_variable && type.pointer && !is_builtin_variable(var) &&
+			    interface_variable_exists_in_entry_point(var.self))
+			{
+				auto name = to_name(var.self);
+				auto &mtype = get<SPIRType>(var.basetype);
+				if (mtype.columns > 1)
+				{
+					// Unroll matrices.
+					for (uint32_t col = 0; col < mtype.columns; col++)
+						statement(name, "[", col, "] = stage_input.", name, "_0;");
 				}
 				else
 				{
-					statement(m.alias, " = input.", m.alias, ";");
+					statement(name, " = stage_input.", name, ";");
 				}
 			}
+
+			// I/O blocks don't use the common stage input/output struct, but separate outputs.
+			if (block && !is_builtin_variable(var) && interface_variable_exists_in_entry_point(var.self))
+			{
+				auto name = to_name(var.self);
+				statement(name, " = stage_input", name, ";");
+			}
 		}
 	}
 
+	// Run the shader.
 	if (execution.model == ExecutionModelVertex)
-	{
 		statement("vert_main();");
-	}
-	else
-	{
+	else if (execution.model == ExecutionModelFragment)
 		statement("frag_main();");
-	}
-
-	statement("Output", post, " output;");
+	else
+		SPIRV_CROSS_THROW("Unsupported shader stage.");
 
+	// Copy block outputs.
 	for (auto &id : ids)
 	{
 		if (id.get_type() == TypeVariable)
 		{
 			auto &var = id.get<SPIRVariable>();
 			auto &type = get<SPIRType>(var.basetype);
+			bool block = (meta[type.self].decoration.decoration_flags & (1ull << DecorationBlock)) != 0;
 
-			if (var.storage != StorageClassFunction && !var.remapped_variable && type.pointer &&
-			    var.storage == StorageClassOutput && interface_variable_exists_in_entry_point(var.self))
+			if (var.storage != StorageClassOutput)
+				continue;
+
+			// I/O blocks don't use the common stage input/output struct, but separate outputs.
+			if (block && !is_builtin_variable(var) && interface_variable_exists_in_entry_point(var.self))
 			{
-				auto &m = meta[var.self].decoration;
-				bool is_no_builtin = !is_builtin_variable(var) && !var.remapped_variable;
-				if (is_no_builtin)
-					statement("output.", m.alias, " = ", m.alias, ";");
-				else if (execution.model == ExecutionModelVertex)
-				{
-					statement("output.gl_Position = gl_Position;");
-				}
+				auto name = to_name(var.self);
+				statement("stage_output", name, " = ", name, ";");
 			}
 		}
 	}
 
-	if (execution.model == ExecutionModelVertex)
+	// Copy stage outputs.
+	if (require_output)
 	{
-		if (options.shader_model <= 30)
-		{
-			statement("output.gl_Position.x = output.gl_Position.x - gl_HalfPixel.x * output.gl_Position.w;");
-			statement("output.gl_Position.y = output.gl_Position.y + gl_HalfPixel.y * output.gl_Position.w;");
-		}
-		if (options.flip_vert_y)
-		{
-			statement("output.gl_Position.y = -output.gl_Position.y;");
-		}
-		if (options.fixup_clipspace)
-		{
-			statement("output.gl_Position.z = (output.gl_Position.z + output.gl_Position.w) * 0.5;");
-		}
-	}
+		statement("SPIRV_Cross_Output stage_output;");
 
-	statement("return output;");
+		// Copy builtins from globals to return struct.
+		for (uint32_t i = 0; i < 64; i++)
+		{
+			if (!(active_output_builtins & (1ull << i)))
+				continue;
+
+			auto builtin = builtin_to_glsl(static_cast<BuiltIn>(i));
+			statement("stage_output.", builtin, " = ", builtin, ";");
+		}
+
+		for (auto &id : ids)
+		{
+			if (id.get_type() == TypeVariable)
+			{
+				auto &var = id.get<SPIRVariable>();
+				auto &type = get<SPIRType>(var.basetype);
+				bool block = (meta[type.self].decoration.decoration_flags & (1ull << DecorationBlock)) != 0;
+
+				if (var.storage != StorageClassOutput)
+					continue;
+
+				if (!block && var.storage != StorageClassFunction && !var.remapped_variable && type.pointer &&
+				    !is_builtin_variable(var) && interface_variable_exists_in_entry_point(var.self))
+				{
+					auto name = to_name(var.self);
+					statement("stage_output.", name, " = ", name, ";");
+				}
+			}
+		}
+
+		if (execution.model == ExecutionModelVertex)
+		{
+			// Do various mangling on the gl_Position.
+			if (options.shader_model <= 30)
+			{
+				statement("stage_output.gl_Position.x = stage_output.gl_Position.x - gl_HalfPixel.x * "
+				          "stage_output.gl_Position.w;");
+				statement("stage_output.gl_Position.y = stage_output.gl_Position.y + gl_HalfPixel.y * "
+				          "stage_output.gl_Position.w;");
+			}
+			if (options.flip_vert_y)
+			{
+				statement("stage_output.gl_Position.y = -stage_output.gl_Position.y;");
+			}
+			if (options.fixup_clipspace)
+			{
+				statement(
+				    "stage_output.gl_Position.z = (stage_output.gl_Position.z + stage_output.gl_Position.w) * 0.5;");
+			}
+		}
+
+		statement("return stage_output;");
+	}
 
 	end_scope();
 }
@@ -993,6 +1298,7 @@ string CompilerHLSL::compile()
 	// Do not deal with ES-isms like precision, older extensions and such.
 	CompilerGLSL::options.es = false;
 	CompilerGLSL::options.version = 450;
+	CompilerGLSL::options.vulkan_semantics = true;
 	backend.float_literal_suffix = true;
 	backend.double_literal_suffix = false;
 	backend.long_long_literal_suffix = true;
@@ -1002,10 +1308,12 @@ string CompilerHLSL::compile()
 	backend.swizzle_is_function = false;
 	backend.shared_is_implied = true;
 	backend.flexible_member_array_supported = false;
-	backend.explicit_struct_type = true;
+	backend.explicit_struct_type = false;
 	backend.use_initializer_list = true;
 	backend.use_constructor_splatting = false;
 
+	update_active_builtins();
+
 	uint32_t pass_count = 0;
 	do
 	{

spirv_hlsl.hpp

@@ -57,7 +57,9 @@ private:
 	void emit_header() override;
 	void emit_resources();
 	void emit_interface_block_globally(const SPIRVariable &type);
-	void emit_interface_block_in_struct(const SPIRVariable &type, uint32_t &binding_number, bool builtins);
+	void emit_interface_block_in_struct(const SPIRVariable &type, std::unordered_set<uint32_t> &active_locations);
+	void emit_builtin_inputs_in_struct();
+	void emit_builtin_outputs_in_struct();
 	void emit_texture_op(const Instruction &i) override;
 	void emit_instruction(const Instruction &instruction) override;
 	void emit_glsl_op(uint32_t result_type, uint32_t result_id, uint32_t op, const uint32_t *args,
@@ -65,11 +67,21 @@ private:
 	void emit_buffer_block(const SPIRVariable &type) override;
 	void emit_push_constant_block(const SPIRVariable &var) override;
 	void emit_uniform(const SPIRVariable &var) override;
+	std::string layout_for_member(const SPIRType &type, uint32_t index) override;
+	std::string to_interpolation_qualifiers(uint64_t flags) override;
 
 	const char *to_storage_qualifiers_glsl(const SPIRVariable &var) override;
 
 	Options options;
 	bool requires_op_fmod = false;
+
+	void emit_builtin_variables();
+	bool require_output = false;
+	bool require_input = false;
+
+	uint32_t type_to_consumed_locations(const SPIRType &type) const;
+
+	void emit_io_block(const SPIRVariable &var);
 };
 }
 

spirv_msl.cpp

@@ -68,6 +68,8 @@ string CompilerMSL::compile()
 	non_stage_in_input_var_ids.clear();
 	struct_member_padding.clear();
 
+	update_active_builtins();
+
 	// Preprocess OpCodes to extract the need to output additional header content
 	set_enabled_interface_variables(get_active_interface_variables());
 	preprocess_op_codes();
@@ -1792,7 +1794,7 @@ string CompilerMSL::argument_decl(const SPIRFunction::Parameter &arg)
 
 // If we're currently in the entry point function, and the object
 // has a qualified name, use it, otherwise use the standard name.
-string CompilerMSL::to_name(uint32_t id, bool allow_alias)
+string CompilerMSL::to_name(uint32_t id, bool allow_alias) const
 {
 	if (current_function && (current_function->self == entry_point))
 	{

spirv_msl.hpp

@@ -136,7 +136,7 @@ protected:
 	std::string constant_expression(const SPIRConstant &c) override;
 	size_t get_declared_struct_member_size(const SPIRType &struct_type, uint32_t index) const override;
 	std::string to_func_call_arg(uint32_t id) override;
-	std::string to_name(uint32_t id, bool allow_alias = true) override;
+	std::string to_name(uint32_t id, bool allow_alias = true) const override;
 	std::string to_function_name(uint32_t img, const SPIRType &imgtype, bool is_fetch, bool is_gather, bool is_proj,
 	                             bool has_array_offsets, bool has_offset, bool has_grad, bool has_lod,
 	                             bool has_dref) override;

test_shaders.py

@@ -107,7 +107,7 @@ def cross_compile_hlsl(shader):
     os.close(hlsl_f)
     subprocess.check_call(['glslangValidator', '-V', '-o', spirv_path, shader])
     spirv_cross_path = './spirv-cross'
-    subprocess.check_call([spirv_cross_path, '--entry', 'main', '--output', hlsl_path, spirv_path, '--hlsl'])
+    subprocess.check_call([spirv_cross_path, '--entry', 'main', '--output', hlsl_path, spirv_path, '--hlsl', '--shader-model', '50'])
     subprocess.check_call(['spirv-val', spirv_path])
 
     validate_shader_hlsl(hlsl_path)