HLSL: HS return is arrayed to match SPIR-V semantics

HLSL HS outputs a per ctrl point value, and the DS reads an array
of that type.  (It also has a per patch frequency).  The per-ctrl-pt
frequency is arrayed on just one side, as opposed to SPIR-V which
is arrayed on both.  To match semantics, the compiler creates an
array behind the scenes and indexes it by invocation ID, assigning
the HS return value to it.

hlsl/hlslParseHelper.h

@@ -80,6 +80,7 @@ public:
     void handleFunctionDeclarator(const TSourceLoc&, TFunction& function, bool prototype);
     TIntermAggregate* handleFunctionDefinition(const TSourceLoc&, TFunction&, const TAttributeMap&, TIntermNode*& entryPointTree);
     TIntermNode* transformEntryPoint(const TSourceLoc&, TFunction&, const TAttributeMap&);
+    void handleEntryPointAttributes(const TSourceLoc&, TFunction&, const TAttributeMap&);
     void handleFunctionBody(const TSourceLoc&, TFunction&, TIntermNode* functionBody, TIntermNode*& node);
     void remapEntryPointIO(TFunction& function, TVariable*& returnValue, TVector<TVariable*>& inputs, TVector<TVariable*>& outputs);
     void remapNonEntryPointIO(TFunction& function);
@@ -283,6 +284,9 @@ protected:
 
     void finish() override; // post-processing
 
+    // Linkage symbol helpers
+    TIntermSymbol* findLinkageSymbol(TBuiltInVariable biType) const;
+
     // Current state of parsing
     struct TPragma contextPragma;
     int loopNestingLevel;        // 0 if outside all loops