HLSL: Support OpArrayLength.

reference/opt/shaders-hlsl/comp/ssbo-array-length.comp

@@ -0,0 +1,15 @@
+RWByteAddressBuffer _11 : register(u1);
+
+void comp_main()
+{
+    uint _14;
+    _11.GetDimensions(_14);
+    _14 = (_14 - 16) / 16;
+    _11.Store(0, uint(int(_14)));
+}
+
+[numthreads(1, 1, 1)]
+void main()
+{
+    comp_main();
+}

reference/opt/shaders/comp/ssbo-array-length.comp

@@ -0,0 +1,14 @@
+#version 450
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+
+layout(binding = 1, std140) buffer SSBO
+{
+    uint size;
+    float v[];
+} _11;
+
+void main()
+{
+    _11.size = uint(int(_11.v.length()));
+}
+

reference/shaders-hlsl/comp/ssbo-array-length.comp

@@ -0,0 +1,15 @@
+RWByteAddressBuffer _11 : register(u1);
+
+void comp_main()
+{
+    uint _14;
+    _11.GetDimensions(_14);
+    _14 = (_14 - 16) / 16;
+    _11.Store(0, uint(int(_14)));
+}
+
+[numthreads(1, 1, 1)]
+void main()
+{
+    comp_main();
+}

reference/shaders/comp/ssbo-array-length.comp

@@ -0,0 +1,14 @@
+#version 450
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+
+layout(binding = 1, std140) buffer SSBO
+{
+    uint size;
+    float v[];
+} _11;
+
+void main()
+{
+    _11.size = uint(int(_11.v.length()));
+}
+

shaders-hlsl/comp/ssbo-array-length.comp

@@ -0,0 +1,12 @@
+#version 450
+layout(local_size_x = 1) in;
+layout(set = 0, binding = 1, std140) buffer SSBO
+{
+	uint size;
+	float v[];
+};
+
+void main()
+{
+	size = v.length();
+}

shaders/comp/ssbo-array-length.comp

@@ -0,0 +1,12 @@
+#version 450
+layout(local_size_x = 1) in;
+layout(set = 0, binding = 1, std140) buffer SSBO
+{
+	uint size;
+	float v[];
+};
+
+void main()
+{
+	size = v.length();
+}

spirv_hlsl.cpp

@@ -4508,6 +4508,25 @@ void CompilerHLSL::emit_instruction(const Instruction &instruction)
 		HLSL_UFOP(reversebits);
 		break;
 
+	case OpArrayLength:
+	{
+		auto *var = maybe_get<SPIRVariable>(ops[2]);
+		if (!var)
+			SPIRV_CROSS_THROW("Array length must point directly to an SSBO block.");
+
+		auto &type = get<SPIRType>(var->basetype);
+		if (!has_decoration(type.self, DecorationBlock) && !has_decoration(type.self, DecorationBufferBlock))
+			SPIRV_CROSS_THROW("Array length expression must point to a block type.");
+
+		// This must be 32-bit uint, so we're good to go.
+		emit_uninitialized_temporary_expression(ops[0], ops[1]);
+		statement(to_expression(ops[2]), ".GetDimensions(", to_expression(ops[1]), ");");
+		uint32_t offset = type_struct_member_offset(type, ops[3]);
+		uint32_t stride = type_struct_member_array_stride(type, ops[3]);
+		statement(to_expression(ops[1]), " = (", to_expression(ops[1]), " - ", offset, ") / ", stride, ";");
+		break;
+	}
+
 	default:
 		CompilerGLSL::emit_instruction(instruction);
 		break;