Implement GetDimensions for structured buffers on WGSL (#6609)

* Implement structured buffer GetDimensions for WGSL

* byte address buffer fix

* enable wgsl test and minor fixups

* maybe fix get equivalent structured buffer

* remove unnecessary include

* clean up some code in meta file

1 files changed, 30 insertions, 0 deletions

diff --git a/source/slang/slang-emit-wgsl.cpp b/source/slang/slang-emit-wgsl.cpp
index d87cd06de..227c6cf75 100644
--- a/source/slang/slang-emit-wgsl.cpp
+++ b/source/slang/slang-emit-wgsl.cpp
@@ -1,5 +1,6 @@
 #include "slang-emit-wgsl.h"
 
+#include "slang-ir-layout.h"
 #include "slang-ir-util.h"
 
 // A note on row/column "terminology reversal".
@@ -1240,6 +1241,35 @@ bool WGSLSourceEmitter::tryEmitInstStmtImpl(IRInst* inst)
             m_writer->emit("(1));\n");
             return true;
         }
+    case kIROp_StructuredBufferGetDimensions:
+        {
+            IRIntegerValue strideValue;
+            auto dataType = inst->getOperand(0)->getDataType();
+            auto structuredBufferType = as<IRHLSLStructuredBufferTypeBase>(dataType);
+            if (structuredBufferType)
+            {
+                auto elementType = structuredBufferType->getElementType();
+                auto sizeDecor = elementType->findDecoration<IRSizeAndAlignmentDecoration>();
+                SLANG_ASSERT(sizeDecor);
+                strideValue = align(sizeDecor->getSize(), (int)sizeDecor->getAlignment());
+            }
+            else
+            {
+                SLANG_ASSERT(as<IRByteAddressBufferTypeBase>(dataType));
+                // ByteAddressBuffer(s) are an array of 32 bit integers, stride is 4 bytes.
+                strideValue = 4;
+            }
+
+            emitInstResultDecl(inst);
+            m_writer->emit("vec2<u32>(");
+            m_writer->emit("arrayLength(&");
+            emitOperand(inst->getOperand(0), getInfo(EmitOp::General));
+            m_writer->emit(")");
+            m_writer->emit(", ");
+            m_writer->emit(strideValue);
+            m_writer->emit(");\n");
+            return true;
+        }
     }
 }