AST Serialization writing (shader-slang#1407)

* Try to fix problem with C++ extractor concating tokens producing an erroneous result.

* Improve naming/comments around C++ extractor fix.

* Another small improvement around space concating when outputing token list.

* Handle some more special cases for consecutive tokens for C++ extractor concat of tokens.

* WIP AST serialization.

* Comment out so compile works.

* More work on AST serialization.

* WIP AST serialize.

* WIP AST Serialization - handling more types.

* WIP: Compiles but not all types are converted, as not all List element types are handled.

* Compiles with array types.

* Finish off AST serialization of remaining types.

* Remove ComputedLayoutModifier and TupleVarModifier.

* Add fields to ASTSerialClass type.

* Construct AST type layout.

* AST Serialization working for writing to ASTSerialWriter.

* Removed call to ASTSerialization::selfTest in session creation.

* Fixes for gcc.

* Diagnostics handling - better handling of dashify.

* Improve comment around DiagnosticLookup.

* Updated VS project.

Author: jsmall-zzz

source/slang/slang-ast-base.h

@@ -275,7 +275,7 @@ class Modifier : public SyntaxNode
     Modifier* next = nullptr;
 
     // The keyword that was used to introduce t that was used to name this modifier.
-    Name* name;
+    Name* name = nullptr;
 
     Name* getName() { return name; }
     NameLoc getNameAndLoc() { return NameLoc(name, loc); }

source/slang/slang-ast-modifier.h

@@ -814,23 +814,6 @@ class HLSLTriangleAdjModifier : public HLSLGeometryShaderInputPrimitiveTypeModif
     SLANG_CLASS(HLSLTriangleAdjModifier)
 };
 
-
-// A modifier to be attached to syntax after we've computed layout
-class ComputedLayoutModifier : public Modifier 
-{
-    SLANG_CLASS(ComputedLayoutModifier)
- 
-    RefPtr<Layout> layout;
-};
-
-
-class TupleVarModifier : public Modifier 
-{
-    SLANG_CLASS(TupleVarModifier)
- 
-//  TupleFieldModifier* tupleField = nullptr;
-};
-
 // A modifier to indicate that a constructor/initializer can be used
 // to perform implicit type conversion, and to specify the cost of
 // the conversion, if applied.

source/slang/slang-ast-reflect.h

@@ -20,7 +20,8 @@
     SLANG_FORCE_INLINE static bool isDerivedFrom(ASTNodeType type) { return int(type) >= int(kType) && int(type) <= int(ASTNodeType::LAST); } \
     SLANG_CLASS_REFLECT_SUPER_##TYPE(SUPER) \
     friend class ASTBuilder; \
-    friend struct ASTConstructAccess;
+    friend struct ASTConstructAccess; \
+    friend struct ASTFieldAccess;
 
 // Macro definitions - use the SLANG_ASTNode_ definitions to invoke the IMPL to produce the code
 // injected into AST classes