Various slangpy fixes. (#3227)

* Make dynamic cast transparent through `IRAttributedType`.

* Add [CUDAXxx] variant of attributes.

* Support marshaling of vector types.

* Wrap cuda kernels in `extern "C"` block.

---------

Co-authored-by: Yong He <yhe@nvidia.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/source/slang/slang-emit-c-like.cpp b/source/slang/slang-emit-c-like.cpp
index a74459954..d26893987 100644
--- a/source/slang/slang-emit-c-like.cpp
+++ b/source/slang/slang-emit-c-like.cpp
@@ -3321,6 +3321,20 @@ bool CLikeSourceEmitter::isTargetIntrinsic(IRInst* inst)
     return findTargetIntrinsicDefinition(inst, intrinsicDef);
 }
 
+bool shouldWrappInExternCBlock(IRFunc* func)
+{
+    for (auto decor : func->getDecorations())
+    {
+        switch (decor->getOp())
+        {
+        case kIROp_ExternCDecoration:
+        case kIROp_CudaKernelDecoration:
+            return true;
+        }
+    }
+    return false;
+}
+
 void CLikeSourceEmitter::emitFunc(IRFunc* func)
 {
     // Target-intrinsic functions should never be emitted
@@ -3329,6 +3343,15 @@ void CLikeSourceEmitter::emitFunc(IRFunc* func)
     if (isTargetIntrinsic(func))
         return;
 
+    bool shouldCloseExternCBlock = shouldWrappInExternCBlock(func);
+    if (shouldCloseExternCBlock)
+    {
+        // If this is a C++ `extern "C"` function, then we need to emit
+        // it as a C function, since that is what the C++ compiler will
+        // expect.
+        //
+        m_writer->emit("extern \"C\" {\n");
+    }
 
     if(!isDefinition(func))
     {
@@ -3345,6 +3368,10 @@ void CLikeSourceEmitter::emitFunc(IRFunc* func)
         //
         emitSimpleFunc(func);
     }
+    if (shouldCloseExternCBlock)
+    {
+        m_writer->emit("}\n");
+    }
 }
 
 void CLikeSourceEmitter::emitFuncDecorationsImpl(IRFunc* func)