Support generic `struct` types during IR-based emit

Fixes #318

Most of the required support was actually in place, so this is just a bunch of fixes:

- Detect when we are in "full IR" mode, so that we can always emit `struct` declarations with their mangled named (which will produce different names for different specializations, since we emit decl-refs)

  - Carefully exclude builtin types from this for now. We'll need a more complete solution for mapping HLSL/Slang builtin types to their GLSL equivalents soon.

- Skip emitting types referenced by generic IR functions, since they might not be usable.

  - Also fix things up so that we emit types used in the initializer for any global variables.

- Fix bug in generic specialization where we specialize the same function more than once, with different type arguments. We were crashing on a `Dictionary::Add` call where the key already exists from a previous specialization attempt.

- Fix name-mangling logic so that when outputting a possibly-specialized generic it looks for the outer-most `GenericSubstitution` rather than just the first one in the list. This is to handle the way that we insert other substitutions willy-nilly in places where they realistically don't belong. :(

All of these changes together allow us to pass a slightly modified (more advanced) version of the test case posted to #318.

1 files changed, 14 insertions, 1 deletions

diff --git a/source/slang/ir.cpp b/source/slang/ir.cpp
index 38a0f0c03..cd36e8d47 100644
--- a/source/slang/ir.cpp
+++ b/source/slang/ir.cpp
@@ -3079,7 +3079,20 @@ namespace Slang
     {
         if(!originalValue)
             return;
-        context->getClonedValues().Add(originalValue, clonedValue);
+
+        // Note: setting the entry direclty here rather than
+        // using `Add` or `AddIfNotExists` because we can conceivably
+        // clone the same value (e.g., a basic block inside a generic
+        // function) multiple times, and that is okay, and we really
+        // just need to keep track of the most recent value.
+
+        // TODO: The same thing could potentially be handled more
+        // cleanly by having a notion of scoping for these cloned-value
+        // mappings, so that we register cloned values for things
+        // inside of a function to a temporary mapping that we
+        // throw away after the function is done.
+
+        context->getClonedValues()[originalValue] = clonedValue;
     }
 
     // Information on values to use when registering a cloned value