Introduce an IR-level type system (#481)

* Introduce an IR-level type system

Up to this point, the Slang IR has used the front-end type system to represent types in the IR.
As a result (but ultimately more importantly) the IR representation of generics and specialization has used AST-level concepts embedded in the IR.
For example, to express the specialization of `vector<T,N>` to a concrete type `float` for `T`, we needed an IR operation that could represent the specialization, with operands that somehow represented the type argument `float`.
The whole thing was very complicated.

The big idea of this change is to introduce a new representation in which types in the IR are just ordinary instructions, so that using them as operands makes sense. The hierarchy of IR types closely mirrors the AST-side hierarchy for now, and that will probably be something we should maintain going forward.

In order to make these changes work, though, I also had to do major overhauls of things like the way substitutions are performed, how we check interface conformances, the way lookup through interface types is done, etc. etc. This is a big change, and unfortunately any attempt to summarize it in the commit message wouldn't do it justice.

* Fix 64-bit build warning

* Fix up some clang warnings/errors

1 files changed, 19 insertions, 1 deletions

diff --git a/tests/bindings/explicit-binding.hlsl b/tests/bindings/explicit-binding.hlsl
index 313f5a091..758be959b 100644
--- a/tests/bindings/explicit-binding.hlsl
+++ b/tests/bindings/explicit-binding.hlsl
@@ -7,6 +7,24 @@
 #define R(X) /**/
 #else
 #define R(X) X
+
+#define CA _SV023SLANG_parameterGroup_CA
+#define ca _SV023SLANG_ParameterGroup_CA2ca
+
+#define CB _SV023SLANG_parameterGroup_CB
+#define cb _SV023SLANG_ParameterGroup_CB2cb
+
+#define CC _SV023SLANG_parameterGroup_CC
+#define cc _SV023SLANG_ParameterGroup_CC2cc
+
+#define sa _SV02sa
+#define sb _SV02sb
+#define sc _SV02sc
+
+#define ta _SV02ta
+#define tb _SV02tb
+#define tc _SV02tc
+
 #endif
 
 float4 use(float4 val) { return val; };
@@ -46,7 +64,7 @@ cbuffer CC : register(b9)
 	float cc;
 }
 
-float4 main() : SV_Target
+float4 main() : SV_TARGET
 {
 	// Go ahead and use everything in this case:
 	return use(ta, sa) + use(ca)