Make interface types non c-style in Slang2026. (#7260)

* Make interface types non c-style.

* Make Optional<T> work with autodiff and existential types.

* Fix.

* patch behind slang 2026.

* Fix warnings.

* cleanup.

* Fix tests.

* Fix.

* Fix com interface lowering.

* Add comment to test.

* regenerate command line reference

* Add test for passing `none` to autodiff function.

* Fix recording of `getDynamicObjectRTTIBytes`.

* Fix nested Optional types.

---------

Co-authored-by: slangbot <186143334+slangbot@users.noreply.github.com>

1 files changed, 39 insertions, 6 deletions

diff --git a/include/slang.h b/include/slang.h
index dc52e80b3..11538bcac 100644
--- a/include/slang.h
+++ b/include/slang.h
@@ -906,7 +906,6 @@ typedef uint32_t SlangSizeT;
         DisableSourceMap,               // bool
         UnscopedEnum,                   // bool
         PreserveParameters, // bool: preserve all resource parameters in the output code.
-
         // Target
 
         Capability,                // intValue0: CapabilityName
@@ -998,8 +997,13 @@ typedef uint32_t SlangSizeT;
         TrackLiveness,
         LoopInversion, // bool, enable loop inversion optimization
 
-        // Deprecated
-        ParameterBlocksUseRegisterSpaces,
+        ParameterBlocksUseRegisterSpaces, // Deprecated
+        LanguageVersion,                  // intValue0: SlangLanguageVersion
+        TypeConformance, // stringValue0: additional type conformance to link, in the format of
+                         // "<TypeName>:<IInterfaceName>[=<sequentialId>]", for example
+                         // "Impl:IFoo=3" or "Impl:IFoo".
+        EnableExperimentalDynamicDispatch, // bool, experimental
+        EmitReflectionJSON,                // bool
 
         CountOfParsableOptions,
 
@@ -1016,14 +1020,11 @@ typedef uint32_t SlangSizeT;
         // Setting of EmitSpirvDirectly or EmitSpirvViaGLSL will turn into this option internally.
         EmitSpirvMethod, // enum SlangEmitSpirvMethod
 
-        EmitReflectionJSON, // bool
         SaveGLSLModuleBinSource,
 
         SkipDownstreamLinking, // bool, experimental
         DumpModule,
 
-        EnableExperimentalDynamicDispatch, // bool, experimental
-        LanguageVersion,                   // intValue0: SlangLanguageVersion
         CountOf,
     };
 
@@ -4052,6 +4053,7 @@ struct ISession : public ISlangUnknown
         ISlangBlob** outNameBlob) = 0;
 
     /** Get the sequential ID used to identify a type witness in a dynamic object.
+        The sequential ID is part of the RTTI bytes returned by `getDynamicObjectRTTIBytes`.
      */
     virtual SLANG_NO_THROW SlangResult SLANG_MCALL getTypeConformanceWitnessSequentialID(
         slang::TypeReflection* type,
@@ -4113,6 +4115,37 @@ struct ISession : public ISlangUnknown
         const char* path,
         const char* string,
         slang::IBlob** outDiagnostics = nullptr) = 0;
+
+
+    /** Get the 16-byte RTTI header to fill into a dynamic object.
+        This header is used to identify the type of the object for dynamic dispatch purpose.
+        For example, given the following shader:
+
+        ```slang
+        [anyValueSize(32)] dyn interface IFoo { int eval(); }
+        struct Impl : IFoo { int eval() { return 1; } }
+
+        ConstantBuffer<dyn IFoo> cb0;
+
+        [numthreads(1,1,1)
+        void main()
+        {
+            cb0.eval();
+        }
+        ```
+
+        The constant buffer `cb0` should be filled with 16+32=48 bytes of data, where the first
+        16 bytes should be the RTTI bytes returned by calling `getDynamicObjectRTTIBytes(type_Impl,
+        type_IFoo)`, and the rest 32 bytes should hold the actual data of the dynamic object (in
+        this case, fields in the `Impl` type).
+
+        `bufferSizeInBytes` must be greater than 16.
+     */
+    virtual SLANG_NO_THROW SlangResult SLANG_MCALL getDynamicObjectRTTIBytes(
+        slang::TypeReflection* type,
+        slang::TypeReflection* interfaceType,
+        uint32_t* outRTTIDataBuffer,
+        uint32_t bufferSizeInBytes) = 0;
 };
 
     #define SLANG_UUID_ISession ISession::getTypeGuid()