HLSL: allow keyword-identifiers as cbuffer/struct names.

Test/hlsl.cbuffer-identifier.vert

+
+cbuffer ConstantBuffer : register( b0 )
+{
+    matrix World;
+    matrix View;
+    matrix Projection;
+};
+
+struct VS_INPUT
+{
+    float4 Pos : POSITION;
+    float3 Norm : NORMAL;
+};
+
+struct PS_INPUT
+{
+    float4 Pos : SV_POSITION;
+    float3 Norm : TEXCOORD0;
+};
+
+PS_INPUT main( VS_INPUT input )
+{
+    int ConstantBuffer = 42;  // test ConstantBuffer as an identifier
+
+    PS_INPUT output = (PS_INPUT)0;
+    output.Pos = mul( input.Pos, World );
+    output.Pos = mul( output.Pos, View );
+    output.Pos = mul( output.Pos, Projection );
+    output.Norm = mul( input.Norm, World );  // Work when output.Norm = mul( input.Norm, (float3x3)World );
+
+    return output;
+}

gtests/Hlsl.FromFile.cpp

@@ -108,6 +108,7 @@ INSTANTIATE_TEST_CASE_P(
         {"hlsl.calculatelod.dx10.frag", "main"},
         {"hlsl.calculatelodunclamped.dx10.frag", "main"},
         {"hlsl.cast.frag", "PixelShaderFunction"},
+        {"hlsl.cbuffer-identifier.vert", "main"},
         {"hlsl.charLit.vert", "main"},
         {"hlsl.clip.frag", "main"},
         {"hlsl.clipdistance-1.frag", "main"},

hlsl/hlslGrammar.cpp

@@ -2029,9 +2029,17 @@ bool HlslGrammar::acceptStruct(TType& type, TIntermNode*& nodeList)
 
     // Now known to be one of CBUFFER, TBUFFER, CLASS, or STRUCT
 
-    // IDENTIFIER
+
+    // IDENTIFIER.  It might also be a keyword which can double as an identifier.
+    // For example:  'cbuffer ConstantBuffer' or 'struct ConstantBuffer' is legal.
+    // 'cbuffer int' is also legal, and 'struct int' appears rejected only because
+    // it attempts to redefine the 'int' type.
+    const char* idString = getTypeString(peek());
     TString structName = "";
-    if (peekTokenClass(EHTokIdentifier)) {
+    if (peekTokenClass(EHTokIdentifier) || idString != nullptr) {
+        if (idString != nullptr)
+            structName = *idString;
+        else
             structName = *token.string;
         advanceToken();
     }
@@ -4056,6 +4064,7 @@ const char* HlslGrammar::getTypeString(EHlslTokenClass tokenClass) const
     case EHTokMin10float: return "min10float";
     case EHTokMin16int:   return "min16int";
     case EHTokMin12int:   return "min12int";
+    case EHTokConstantBuffer: return "ConstantBuffer";
     default:
         return nullptr;
     }