[clang] Implement resource binding type prefix mismatch errors (PR #87578)

[Tex Riddell via cfe-commits]

================
@@ -0,0 +1,74 @@
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -x hlsl -o - -fsyntax-only %s -verify
+
+// the below will cause an llvm unreachable, because RWBuffers don't have resource attributes yet
+// NOT YET IMPLEMENTED : {{invalid register name prefix 'b' for register type 'RWBuffer' (expected 'u')}}
+// NOT YET IMPLEMENTED RWBuffer<int> a : register(b2, space1);
+
+// the below will cause an llvm unreachable, because RWBuffers don't have resource attributes yet
+// NOT YET IMPLEMENTED : {{invalid register name prefix 't' for register type 'RWBuffer' (expected 'u')}}
+// NOT YET IMPLEMENTED RWBuffer<int> b : register(t2, space1);
+
+// NOT YET IMPLEMENTED : {{invalid register name prefix 'u' for register type 'Texture1D' (expected 't')}}
+// NOT YET IMPLEMENTED Texture1D<float> tex : register(u3);
+
+// NOT YET IMPLEMENTED : {{invalid register name prefix 's' for register type 'Texture2D' (expected 't')}}
+// NOT YET IMPLEMENTED Texture2D<float> Texture : register(s0);
+
+// NOT YET IMPLEMENTED : {{invalid register name prefix 'u' for register type 'Texture2DMS' (expected 't')}}
+// NOT YET IMPLEMENTED Texture2DMS<float4, 4> T2DMS_t2 : register(u2)
+
+// NOT YET IMPLEMENTED : {{invalid register name prefix 't' for register type 'RWTexture3D' (expected 'u')}}
+// NOT YET IMPLEMENTED RWTexture3D<float4> RWT3D_u1 : register(t1)
+
+// NOT YET IMPLEMENTED : {{invalid register name prefix 'b' for register type 'Texture2DMS' (expected 't' or 's')}}
+// NOT YET IMPLEMENTED TextureCube TCube_b2 : register(B2);
+
+// NOT YET IMPLEMENTED : {{invalid register name prefix 'b' for register type 'Texture2DMS' (expected 't')}}
+// NOT YET IMPLEMENTED TextureCubeArray TCubeArray_t2 : register(b2);
+
+// NOT YET IMPLEMENTED : {{invalid register name prefix 'b' for register type 'Texture2DMS' (expected 't' or 's')}}
+// NOT YET IMPLEMENTED Texture1DArray T1DArray_t2 : register(b2);
+
+// NOT YET IMPLEMENTED : {{invalid register name prefix 'u' for register type 'Texture2DMS' (expected 't' or 's')}}
+// NOT YET IMPLEMENTED Texture2DArray T2DArray_b2 : register(B2);
+
+// NOT YET IMPLEMENTED : {{invalid register name prefix 'u' for register type 'Texture2DMS' (expected 'b' or 'c' or 'i')}}
+// NOT YET IMPLEMENTED Texture2DMSArray<float4> msTextureArray : register(t2, space2);
----------------
tex3d wrote:

Expected would be 't', not `'b' or 'c' or 'i'`.  In fact, that group ('b', 'c', 'i') were legacy constant register bindings for DX9, which is where I suspect this comes from, where 'b' meant a special bool constant and 'i' mapped to special loop constant values (used in DX9 shader models), and 'c' was a float constant value.  'b' was since used for constant buffer binding location as well, so there is a bit of a collision, but not on the same variable type, since the 'b', 'c', 'i' bindings were on global numeric variables, not on resource objects or cbuffer/tbuffer declarations.

So, we no longer support the DX9 'b','c','i' numeric constant bindings the same way, but we do reuse 'c' for manual cbuffer layout, and 'b' for cbuffer or ConstantBuffer binding.

https://github.com/llvm/llvm-project/pull/87578