Modified the new type system to support generic differentiable types … (#2413)

* Modified the new type system to support generic differentiable types and added support for differentiating overloaded functions.

* Changed a few asserts to release asserts to avoid unreferenced variable errors

* Fixed a naming issue with TypeWitnessBreadcumb::Flavor::Decl

* Added logic to avoid tracking differentiable types if the module does not use auto-diff or define differentiable types.

* Moved the auto-diff passes to after the specialization step, added a more complex generics test

* Added a generics stress test and fixed AST-side logic. IR side needs some more work

* Added differential getter and setter logic, fixed multiple issues with DifferentiableTypeDictionary, added support for loops and conditions

* Changed differential getters to use pointer types, added getter type checking

* Fixed some bugs related to diff type registration and differential getters

* Removed some superfluous code

* Removed some more unused code.

* Fixed an issue with witness substitution

* Minor fix

Co-authored-by: Yong He <yonghe@outlook.com>

1 files changed, 22 insertions, 2 deletions

diff --git a/source/slang/slang-ast-expr.h b/source/slang/slang-ast-expr.h
index 13d687da0..e0a55cc29 100644
--- a/source/slang/slang-ast-expr.h
+++ b/source/slang/slang-ast-expr.h
@@ -38,6 +38,18 @@ class VarExpr : public DeclRefExpr
     SLANG_AST_CLASS(VarExpr)
 };
 
+class DifferentiableDeclRefExpr : public Expr
+{
+    SLANG_AST_CLASS(DifferentiableDeclRefExpr)
+
+    // Inner decl ref expr that references a differentiable expression.
+    Expr* inner = nullptr;
+
+    // Information on getters and setters if available.
+    Expr* setterExpr = nullptr;
+    Expr* getterExpr = nullptr;
+};
+
 // An expression that references an overloaded set of declarations
 // having the same name.
 class OverloadedExpr : public Expr
@@ -428,13 +440,21 @@ class OpenRefExpr : public Expr
     Expr* innerExpr = nullptr;
 };
 
+    /// Base class for higher-order function application
+    /// Eg: foo(fn) where fn is a function expression.
+    ///
+class HigherOrderInvokeExpr : public Expr
+{
+    SLANG_ABSTRACT_AST_CLASS(HigherOrderInvokeExpr)
+    Expr* baseFunction;
+};
+
     /// An expression of the form `__jvp(fn)` to access the 
     /// forward-mode derivative version of the function `fn`
     ///
-class JVPDifferentiateExpr: public Expr
+class JVPDifferentiateExpr: public HigherOrderInvokeExpr
 {
     SLANG_AST_CLASS(JVPDifferentiateExpr)
-    Expr* baseFunction;
 };
 
     /// A type expression of the form `__TaggedUnion(A, ...)`.