WIP: HLSL: hlsl register class iomapping

Adds --hlsl-iomap option to perform IO mapping in HLSL register space.

--shift-cbuffer-binding is now a synonym for --shift-ubo-binding.

The idea way to do this seems to be passing in a dedicated IO resolver, but
that would require more intrusive restructuring, so maybe best for its
own PR.

The TDefaultHlslIoResolver class and the former TDefaultIoResolver class
share quite a bit of mechanism in a common base class.

TODO: tbuffers are landing in the wrong register class, which needs some
investigation.  They're either wrong upstream, or the detection in the
resolver is wrong.

glslang/MachineIndependent/localintermediate.h

@@ -175,11 +175,13 @@ public:
         shiftImageBinding(0),
         shiftUboBinding(0),
         shiftSsboBinding(0),
+        shiftUavBinding(0),
         autoMapBindings(false),
         flattenUniformArrays(false),
         useUnknownFormat(false),
         hlslOffsets(false),
-        useStorageBuffer(false)
+        useStorageBuffer(false),
+        hlslIoMapping(false)
     {
         localSize[0] = 1;
         localSize[1] = 1;
@@ -212,6 +214,8 @@ public:
     unsigned int getShiftUboBinding()     const { return shiftUboBinding; }
     void setShiftSsboBinding(unsigned int shift)     { shiftSsboBinding = shift; }
     unsigned int getShiftSsboBinding()  const { return shiftSsboBinding; }
+    void setShiftUavBinding(unsigned int shift) { shiftUavBinding = shift; }
+    unsigned int getShiftUavBinding()  const { return shiftUavBinding; }
     void setAutoMapBindings(bool map)               { autoMapBindings = map; }
     bool getAutoMapBindings()             const { return autoMapBindings; }
     void setFlattenUniformArrays(bool flatten)      { flattenUniformArrays = flatten; }
@@ -222,6 +226,8 @@ public:
     bool usingHlslOFfsets() const { return hlslOffsets; }
     void setUseStorageBuffer() { useStorageBuffer = true; }
     bool usingStorageBuffer() const { return useStorageBuffer; }
+    void setHlslIoMapping(bool b) { hlslIoMapping = b; }
+    bool usingHlslIoMapping()     { return hlslIoMapping; }
 
     void setVersion(int v) { version = v; }
     int getVersion() const { return version; }
@@ -505,11 +511,13 @@ protected:
     unsigned int shiftImageBinding;
     unsigned int shiftUboBinding;
     unsigned int shiftSsboBinding;
+    unsigned int shiftUavBinding;
     bool autoMapBindings;
     bool flattenUniformArrays;
     bool useUnknownFormat;
     bool hlslOffsets;
     bool useStorageBuffer;
+    bool hlslIoMapping;
 
     typedef std::list<TCall> TGraph;
     TGraph callGraph;