Add a flag to control type splitting

The `-split-mixed-types` flag can be provided to command-line `slangc`, and the `SLANG_COMPILE_FLAG_SPLIT_MIXED_TYPE` flag can be passed to `spSetCompileFlags`.
Either of these turns on a mode where Slang will split types that included both resource and non-resource fields.
The declaration of such a type will just drop the resource fields, while a variable declare using such a type turns into multiple declararations: one for the non-resource fields, and then one for each resource field (recursively).

This behavior was already implemented for GLSL support, and this change just adds a flag so that the user can turn it on unconditionally.

Caveats:

- This does not apply in "full rewriter" mode, which is what happens if the user doesn't use any `import`s. I could try to fix that, but it seems like in that mode people are asking to bypass as much of the compiler as possible.

- When it *does* apply, it applies to user code as well as library/Slang code. So this will potentially rewrite the user's own HLSL in ways they wouldn't expect. I don't see a great way around it, though.

1 files changed, 5 insertions, 1 deletions

diff --git a/slang.h b/slang.h
index 2f6c112c0..3ed715f23 100644
--- a/slang.h
+++ b/slang.h
@@ -93,7 +93,11 @@ extern "C"
     typedef unsigned int SlangCompileFlags;
     enum
     {
-        SLANG_COMPILE_FLAG_NO_CHECKING = 1 << 0, /**< Disable semantic checking as much as possible. */
+         /** Disable semantic checking as much as possible. */
+        SLANG_COMPILE_FLAG_NO_CHECKING          = 1 << 0,
+
+        /* Split apart types that contain a mix of resource and non-resource data */
+        SLANG_COMPILE_FLAG_SPLIT_MIXED_TYPES    = 1 << 1,
     };
 
     /*!