Implement type splitting for raw buffers (shader-slang#393)

* Fix render-test to handle raw buffers

I don't know if this fix will work for UAVs that are neither structured nor raw, but it fixes the code that currently only really works if every UAV is structured (since it doesn't set a format).

* Make type legalization consider raw buffer types

The type layout logic was already handling these, but the type splitting logic in legalization was failing to split structure types that contain, e.g., `RWByteAddressBuffer`.

A compute test case has been added to confirm the fix.

Author: Tim Foley

source/slang/legalize-types.cpp

@@ -91,6 +91,10 @@ static bool isResourceType(Type* type)
     {
         return true;
     }
+    else if(auto untypedBufferType = type->As<UntypedBufferResourceType>())
+    {
+        return true;
+    }
 
     // TODO: need more comprehensive coverage here
 

tests/compute/buffer-type-splitting.slang

@@ -0,0 +1,29 @@
+//TEST(compute):COMPARE_COMPUTE:
+//TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):dxbinding(0),glbinding(0),out
+//TEST_INPUT:ubuffer(data=[0 2 3 3]):dxbinding(1),glbinding(1)
+//TEST_INPUT:ubuffer(data=[4 5 6 7]):dxbinding(2),glbinding(2)
+//TEST_INPUT:ubuffer(data=[8 9 10 11]):dxbinding(3),glbinding(3)
+//TEST_INPUT:ubuffer(data=[12 13 14 15]):dxbinding(4),glbinding(4)
+
+RWStructuredBuffer<int> outputBuffer;
+
+struct S
+{
+	RWByteAddressBuffer a;
+	RWByteAddressBuffer b;
+};
+S s[2];
+
+[numthreads(4, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    uint i = dispatchThreadID.x;
+
+    int val =
+          s[0].a.Load(i * 4)
+        + s[1].a.Load(i * 4)*16
+        + s[0].b.Load(i * 4)*256
+        + s[1].b.Load(i * 4)*4096;
+
+    outputBuffer[i] = val; 
+}

tests/compute/buffer-type-splitting.slang.expected.txt

@@ -0,0 +1,4 @@
+C840
+D952
+EA63
+FB73

tools/render-test/render-d3d11.cpp

@@ -815,6 +815,16 @@ class D3D11Renderer : public Renderer, public ShaderCompiler
             viewDesc.Buffer.Flags = 0;
             viewDesc.ViewDimension = D3D11_UAV_DIMENSION_BUFFER;
             viewDesc.Format = DXGI_FORMAT_UNKNOWN;
+
+            if( bufferDesc.stride == 0 )
+            {
+                // TODO: are there UAV cases we need to handle that are neither
+                // raw nor structured? RWBuffer<T> would be one...
+
+                viewDesc.Buffer.Flags |= D3D11_BUFFER_UAV_FLAG_RAW;
+                viewDesc.Format = DXGI_FORMAT_R32_TYPELESS;
+            }
+
             dxDevice->CreateUnorderedAccessView(bufferOut, &viewDesc, &viewOut);
         }
         if (bufferDesc.type != InputBufferType::ConstantBuffer)