Make SourceMap a value type (#2812)

* #include an absolute path didn't work - because paths were taken to always be relative.

* Moved JSON source map writing logic to JSONSourceMapUtil.

* Use ArtifactHandler to read/write SourceMaps.
Use ObjectCastableAdapter to hold SourceMap
Only serialize SourceMap <-> JSON on demand.

* Make some types swappable.

* BoxValue impl.

* Added asBoxValue.

* Remove const get funcs.

* Fix typo in asBoxValue.

* Fix another typo in asBoxValue.

* Slightly simplify conversion to blob of SourceMap.

* Small fix for asBoxValue

24 files changed, 245 insertions, 154 deletions

diff --git a/source/compiler-core/slang-artifact-handler-impl.cpp b/source/compiler-core/slang-artifact-handler-impl.cpp
index 1a8e8374d..5d2a74036 100644
--- a/source/compiler-core/slang-artifact-handler-impl.cpp
+++ b/source/compiler-core/slang-artifact-handler-impl.cpp
@@ -130,7 +130,7 @@ SlangResult DefaultArtifactHandler::expandChildren(IArtifact* container)
 	return SLANG_OK;
 }
 
-static SlangResult _loadSourceMap(IArtifact* artifact, ArtifactKeep intermediateKeep, RefPtr<SourceMap>& outSourceMap)
+static SlangResult _loadSourceMap(IArtifact* artifact, ArtifactKeep intermediateKeep, SourceMap& outSourceMap)
 {
 	const auto desc = artifact->getDesc();
 	if (isDerivedFrom(desc.kind, ArtifactKind::Json) &&
@@ -139,10 +139,7 @@ static SlangResult _loadSourceMap(IArtifact* artifact, ArtifactKeep intermediate
 		ComPtr<ISlangBlob> blob;
 		SLANG_RETURN_ON_FAIL(artifact->loadBlob(intermediateKeep, blob.writeRef()));
 
-		RefPtr<SourceMap> sourceMap;
-		SLANG_RETURN_ON_FAIL(JSONSourceMapUtil::read(blob, sourceMap));
-
-		outSourceMap = sourceMap;
+		SLANG_RETURN_ON_FAIL(JSONSourceMapUtil::read(blob, outSourceMap));
 		return SLANG_OK;
 	}
 
@@ -183,10 +180,9 @@ SlangResult DefaultArtifactHandler::getOrCreateRepresentation(IArtifact* artifac
 	if (guid == SourceMap::getTypeGuid())
 	{
 		// Blob -> SourceMap
-		RefPtr<SourceMap> sourceMap;
-		SLANG_RETURN_ON_FAIL(_loadSourceMap(artifact, getIntermediateKeep(keep), sourceMap));
-		ComPtr<IObjectCastableAdapter> castable(new ObjectCastableAdapter(sourceMap));
-		return _addRepresentation(artifact, keep, castable, outCastable);
+		ComPtr<IBoxValue<SourceMap>> sourceMap(new BoxValue<SourceMap>);
+		SLANG_RETURN_ON_FAIL(_loadSourceMap(artifact, getIntermediateKeep(keep), sourceMap->get()));
+		return _addRepresentation(artifact, keep, sourceMap, outCastable);
 	}
 	else if (guid == ISlangSharedLibrary::getTypeGuid())
 	{
@@ -200,18 +196,17 @@ SlangResult DefaultArtifactHandler::getOrCreateRepresentation(IArtifact* artifac
 		SLANG_RETURN_ON_FAIL(_createOSFile(artifact, getIntermediateKeep(keep), fileRep.writeRef()));
 		return _addRepresentation(artifact, keep, fileRep, outCastable);
 	}
-	else if (guid == ISlangBlob::getTypeGuid())
+
+	// Handle known conversion to blobs 
+	if (guid == ISlangBlob::getTypeGuid())
 	{
-		for (ICastable* rep : reps)
-		{
-			if (SourceMap* sourceMap = as<SourceMap>(rep))
-			{
-				// SourceMap -> Blob
-				ComPtr<ISlangBlob> blob;
-				SLANG_RETURN_ON_FAIL(JSONSourceMapUtil::write(sourceMap, blob));
-				// Add the rep
-				return _addRepresentation(artifact, keep, blob, outCastable);
-			}
+		if (auto sourceMap = findRepresentation<SourceMap>(artifact))
+		{	
+			// SourceMap -> Blob
+			ComPtr<ISlangBlob> blob;
+			SLANG_RETURN_ON_FAIL(JSONSourceMapUtil::write(*sourceMap, blob));
+			// Add the rep
+			return _addRepresentation(artifact, keep, blob, outCastable);
 		}
 	}
 
diff --git a/source/compiler-core/slang-json-source-map-util.cpp b/source/compiler-core/slang-json-source-map-util.cpp
index 4ef6ee3d6..193c812b7 100644
--- a/source/compiler-core/slang-json-source-map-util.cpp
+++ b/source/compiler-core/slang-json-source-map-util.cpp
@@ -172,9 +172,9 @@ void _encode(Index v, StringBuilder& out)
     out.append(dst, cur);
 }
 
-/* static */SlangResult JSONSourceMapUtil::decode(JSONContainer* container, JSONValue root, DiagnosticSink* sink, RefPtr<SourceMap>& out)
+/* static */SlangResult JSONSourceMapUtil::decode(JSONContainer* container, JSONValue root, DiagnosticSink* sink, SourceMap& outSourceMap)
 {
-    RefPtr<SourceMap> sourceMap(new SourceMap);
+    outSourceMap.clear();
 
     // Let's try and decode the JSON into native types to make this easier...
     RttiTypeFuncsMap typeMap = JSONNativeUtil::getTypeFuncsMap();
@@ -188,23 +188,23 @@ void _encode(Index v, StringBuilder& out)
         SLANG_RETURN_ON_FAIL(converter.convert(root, GetRttiInfo<JSONSourceMap>::get(), &native));
     }
 
-    sourceMap->m_file = native.file;
-    sourceMap->m_sourceRoot = native.sourceRoot;
+    outSourceMap.m_file = native.file;
+    outSourceMap.m_sourceRoot = native.sourceRoot;
 
     const Count sourcesCount = native.sources.getCount();
     
     // These should all be unique, but for simplicity, we build a table
-    sourceMap->m_sources.setCount(sourcesCount);
+    outSourceMap.m_sources.setCount(sourcesCount);
     for (Index i = 0; i < sourcesCount; ++i)
     {
-        sourceMap->m_sources[i] = sourceMap->m_slicePool.add(native.sources[i]);
+        outSourceMap.m_sources[i] = outSourceMap.m_slicePool.add(native.sources[i]);
     }
 
     Count sourcesContentCount = native.sourcesContent.getCount();
     sourcesContentCount = std::min(sourcesContentCount, sourcesCount);
 
-    sourceMap->m_sourcesContent.setCount(sourcesContentCount);
-    for (auto& cur : sourceMap->m_sourcesContent)
+    outSourceMap.m_sourcesContent.setCount(sourcesContentCount);
+    for (auto& cur : outSourceMap.m_sourcesContent)
     {
         cur = StringSlicePool::kNullHandle;
     }
@@ -218,7 +218,7 @@ void _encode(Index v, StringBuilder& out)
             if (value.getKind() == JSONValue::Kind::String)
             {
                 auto stringValue = container->getString(value);
-                sourceMap->m_sourcesContent[i] = sourceMap->m_slicePool.add(stringValue);
+                outSourceMap.m_sourcesContent[i] = outSourceMap.m_slicePool.add(stringValue);
             }
         }
     }
@@ -237,13 +237,13 @@ void _encode(Index v, StringBuilder& out)
 
     const Count linesCount = lines.getCount();
 
-    sourceMap->m_lineStarts.setCount(linesCount + 1);
+    outSourceMap.m_lineStarts.setCount(linesCount + 1);
 
     for (Index generatedLine = 0; generatedLine < linesCount; ++generatedLine)
     {
         const auto line = lines[generatedLine];
 
-        sourceMap->m_lineStarts[generatedLine] = sourceMap->m_lineEntries.getCount();
+        outSourceMap.m_lineStarts[generatedLine] = outSourceMap.m_lineEntries.getCount();
 
         // If it's empty move to next line
         if (line.getLength() == 0)
@@ -312,47 +312,45 @@ void _encode(Index v, StringBuilder& out)
             entry.sourceFileIndex = sourceFileIndex;
             entry.nameIndex = nameIndex;
 
-            sourceMap->m_lineEntries.add(entry);
+            outSourceMap.m_lineEntries.add(entry);
         }
     }
 
     // Mark the end
-    sourceMap->m_lineStarts[linesCount] = sourceMap->m_lineEntries.getCount();
-
-    out.swapWith(sourceMap);
+    outSourceMap.m_lineStarts[linesCount] = outSourceMap.m_lineEntries.getCount();
 
     return SLANG_OK;
 }
 
-SlangResult JSONSourceMapUtil::encode(SourceMap* sourceMap, JSONContainer* container, DiagnosticSink* sink, JSONValue& outValue)
+SlangResult JSONSourceMapUtil::encode(const SourceMap& sourceMap, JSONContainer* container, DiagnosticSink* sink, JSONValue& outValue)
 {
     // Convert to native
     JSONSourceMap native;
 
-    native.file = sourceMap->m_file;
-    native.sourceRoot = sourceMap->m_sourceRoot;
+    native.file = sourceMap.m_file;
+    native.sourceRoot = sourceMap.m_sourceRoot;
 
     // Copy over the sources
     {
-        const auto count = sourceMap->m_sources.getCount();
+        const auto count = sourceMap.m_sources.getCount();
         native.sources.setCount(count);
         for (Index i = 0; i < count; ++i)
         {
-            native.sources[i] = sourceMap->m_slicePool.getSlice(sourceMap->m_sources[i]);
+            native.sources[i] = sourceMap.m_slicePool.getSlice(sourceMap.m_sources[i]);
         }
     }
 
     // Copy out the sourcesContent, care is needed around handling null
     {
-        const auto count = sourceMap->m_sourcesContent.getCount();
+        const auto count = sourceMap.m_sourcesContent.getCount();
         native.sourcesContent.setCount(count);
         for (Index i = 0; i < count; ++i)
         {
-            const auto srcValue = sourceMap->m_sourcesContent[i];
+            const auto srcValue = sourceMap.m_sourcesContent[i];
             
             const JSONValue dstValue = (srcValue == StringSlicePool::kNullHandle) ?
                 native.sourcesContent[i] = JSONValue::makeNull() :
-                container->createString(sourceMap->m_slicePool.getSlice(srcValue));
+                container->createString(sourceMap.m_slicePool.getSlice(srcValue));
 
             native.sourcesContent[i] = dstValue;
         }
@@ -360,11 +358,11 @@ SlangResult JSONSourceMapUtil::encode(SourceMap* sourceMap, JSONContainer* conta
 
     // Copy out the names
     {
-        const auto count = sourceMap->m_names.getCount();
+        const auto count = sourceMap.m_names.getCount();
         native.names.setCount(count);
         for (Index i = 0; i < count; ++i)
         {
-            native.names[i] = sourceMap->m_slicePool.getSlice(sourceMap->m_names[i]);
+            native.names[i] = sourceMap.m_slicePool.getSlice(sourceMap.m_names[i]);
         }
     }
 
@@ -372,7 +370,7 @@ SlangResult JSONSourceMapUtil::encode(SourceMap* sourceMap, JSONContainer* conta
 
     // Do the encoding!
     {
-        const Count linesCount = sourceMap->getGeneratedLineCount();
+        const Count linesCount = sourceMap.getGeneratedLineCount();
 
         Index sourceFileIndex = 0;
 
@@ -388,7 +386,7 @@ SlangResult JSONSourceMapUtil::encode(SourceMap* sourceMap, JSONContainer* conta
                 mappings.appendChar(';');
             }
 
-            const auto entries = sourceMap->getEntriesForLine(i);
+            const auto entries = sourceMap.getEntriesForLine(i);
             const auto entriesCount = entries.getCount();
 
             if (entriesCount == 0)
@@ -455,13 +453,15 @@ SlangResult JSONSourceMapUtil::encode(SourceMap* sourceMap, JSONContainer* conta
     return SLANG_OK;
 }
 
-/* static */SlangResult JSONSourceMapUtil::read(ISlangBlob* blob, RefPtr<SourceMap>& outSourceMap)
+/* static */SlangResult JSONSourceMapUtil::read(ISlangBlob* blob, SourceMap& outSourceMap)
 {
     return read(blob, nullptr, outSourceMap);
 }
 
-SlangResult JSONSourceMapUtil::read(ISlangBlob* blob, DiagnosticSink* parentSink, RefPtr<SourceMap>& outSourceMap)
+SlangResult JSONSourceMapUtil::read(ISlangBlob* blob, DiagnosticSink* parentSink, SourceMap& outSourceMap)
 {
+    outSourceMap.clear();
+
     SourceManager sourceManager;
     sourceManager.initialize(nullptr, nullptr);
     DiagnosticSink sink(&sourceManager, nullptr);
@@ -487,16 +487,13 @@ SlangResult JSONSourceMapUtil::read(ISlangBlob* blob, DiagnosticSink* parentSink
         rootValue = builder.getRootValue();
     }
 
-    RefPtr<SourceMap> sourceMap;
-
-    SLANG_RETURN_ON_FAIL(decode(container, rootValue, &sink, sourceMap));
+    SLANG_RETURN_ON_FAIL(decode(container, rootValue, &sink, outSourceMap));
 
-    outSourceMap = sourceMap;
     return SLANG_OK;
 }
 
 
-/* static */SlangResult JSONSourceMapUtil::write(SourceMap* sourceMap, ComPtr<ISlangBlob>& outBlob)
+/* static */SlangResult JSONSourceMapUtil::write(const SourceMap& sourceMap, ComPtr<ISlangBlob>& outBlob)
 {
     SourceManager sourceMapSourceManager;
     sourceMapSourceManager.initialize(nullptr, nullptr);
@@ -508,7 +505,7 @@ SlangResult JSONSourceMapUtil::read(ISlangBlob* blob, DiagnosticSink* parentSink
     return SLANG_OK;
 }
 
-/* static */ SlangResult JSONSourceMapUtil::write(SourceMap* sourceMap, DiagnosticSink* sink, ComPtr<ISlangBlob>& outBlob)
+/* static */ SlangResult JSONSourceMapUtil::write(const SourceMap& sourceMap, DiagnosticSink* sink, ComPtr<ISlangBlob>& outBlob)
 {
     auto sourceManager = sink->getSourceManager();
 
diff --git a/source/compiler-core/slang-json-source-map-util.h b/source/compiler-core/slang-json-source-map-util.h
index 8d5071d4e..d61936ce4 100644
--- a/source/compiler-core/slang-json-source-map-util.h
+++ b/source/compiler-core/slang-json-source-map-util.h
@@ -10,20 +10,20 @@ namespace Slang {
 struct  JSONSourceMapUtil
 {
         /// Decode from root into the source map
-    static SlangResult decode(JSONContainer* container, JSONValue root, DiagnosticSink* sink, RefPtr<SourceMap>& out);
+    static SlangResult decode(JSONContainer* container, JSONValue root, DiagnosticSink* sink, SourceMap& out);
 
         /// Converts the source map contents into JSON
-    static SlangResult encode(SourceMap* sourceMap, JSONContainer* container, DiagnosticSink* sink, JSONValue& outValue);
+    static SlangResult encode(const SourceMap& sourceMap, JSONContainer* container, DiagnosticSink* sink, JSONValue& outValue);
 
         /// Read the blob (encoded as JSON) as a source map. 
         /// Sink is optional, and can be passed as nullptr
-    static SlangResult read(ISlangBlob* blob, DiagnosticSink* sink, RefPtr<SourceMap>& outSourceMap);
-    static SlangResult read(ISlangBlob* blob, RefPtr<SourceMap>& outSourceMap);
+    static SlangResult read(ISlangBlob* blob, DiagnosticSink* sink, SourceMap& outSourceMap);
+    static SlangResult read(ISlangBlob* blob, SourceMap& outSourceMap);
 
         /// Write source map to outBlob JSON
-    static SlangResult write(SourceMap* sourceMap, ComPtr<ISlangBlob>& outBlob);
+    static SlangResult write(const SourceMap& sourceMap, ComPtr<ISlangBlob>& outBlob);
         /// Write out the source map into a blob
-    static SlangResult write(SourceMap* sourceMap, DiagnosticSink* sink, ComPtr<ISlangBlob>& outBlob);
+    static SlangResult write(const SourceMap& sourceMap, DiagnosticSink* sink, ComPtr<ISlangBlob>& outBlob);
 };
 
 } // namespace Slang
diff --git a/source/compiler-core/slang-source-loc.cpp b/source/compiler-core/slang-source-loc.cpp
index 23cbdf839..3d992ee8d 100644
--- a/source/compiler-core/slang-source-loc.cpp
+++ b/source/compiler-core/slang-source-loc.cpp
@@ -211,7 +211,7 @@ SlangResult _findLocWithSourceMap(SourceManager* lookupSourceManager, SourceView
         auto sourceMap = sourceFile->getSourceMap();
         SLANG_ASSERT(sourceMap);
 
-        entryIndex = sourceMap->findEntry(lineIndex, colIndex);   
+        entryIndex = sourceMap->get().findEntry(lineIndex, colIndex);   
     }
 
     if (entryIndex < 0)
@@ -222,7 +222,7 @@ SlangResult _findLocWithSourceMap(SourceManager* lookupSourceManager, SourceView
     // Keep searching through source maps 
     do 
     {
-        auto sourceMap = sourceFile->getSourceMap();
+        auto sourceMap = sourceFile->getSourceMap()->getPtr();
 
         // Find the entry
         const auto& entry = sourceMap->getEntryByIndex(entryIndex);
@@ -242,7 +242,7 @@ SlangResult _findLocWithSourceMap(SourceManager* lookupSourceManager, SourceView
                     // If it has a source map, we try and look up the current location in it's source map
                     if (auto foundSourceMap = foundSourceFile->getSourceMap())
                     {
-                        const auto foundEntryIndex = foundSourceMap->findEntry(entry.sourceLine, entry.sourceColumn);
+                        const auto foundEntryIndex = foundSourceMap->get().findEntry(entry.sourceLine, entry.sourceColumn);
 
                         // If we found the entry repeat the lookup
                         if (foundEntryIndex >= 0)
@@ -258,7 +258,7 @@ SlangResult _findLocWithSourceMap(SourceManager* lookupSourceManager, SourceView
     } while (false);
 
     // Generate the HandleSourceLoc
-    auto sourceMap = sourceFile->getSourceMap();
+    auto sourceMap = sourceFile->getSourceMap()->getPtr();
     const auto& entry = sourceMap->getEntryByIndex(entryIndex);
 
     // We need to add the pool of the originating source view/file
diff --git a/source/compiler-core/slang-source-loc.h b/source/compiler-core/slang-source-loc.h
index 98b1bdbbd..fafff7de6 100644
--- a/source/compiler-core/slang-source-loc.h
+++ b/source/compiler-core/slang-source-loc.h
@@ -5,6 +5,7 @@
 #include "../core/slang-basic.h"
 #include "../core/slang-memory-arena.h"
 #include "../core/slang-string-slice-pool.h"
+#include "../core/slang-castable.h"
 
 #include "slang-source-map.h"
 
@@ -254,9 +255,9 @@ public:
 
         /// Get the source map associated with this file. If it's set when doing 
         /// lookup for source locations, the source map will be used
-    SourceMap* getSourceMap() const { return m_sourceMap; }
+    IBoxValue<SourceMap>* getSourceMap() const { return m_sourceMap; }
         /// Set a source map
-    void setSourceMap(SourceMap* sourceMap) { m_sourceMap = sourceMap; }
+    void setSourceMap(IBoxValue<SourceMap>* sourceMap) { m_sourceMap = sourceMap; }
 
         /// Ctor
     SourceFile(SourceManager* sourceManager, const PathInfo& pathInfo, size_t contentSize);
@@ -279,7 +280,7 @@ public:
 
     // If set then the locations in this file are really from locations from elsewhere, 
     // where the SourceMap specifies that mapping
-    RefPtr<SourceMap> m_sourceMap;
+    ComPtr<IBoxValue<SourceMap>> m_sourceMap;
 };
 
 enum class SourceLocType
diff --git a/source/compiler-core/slang-source-map.cpp b/source/compiler-core/slang-source-map.cpp
index 4ea50eb3f..7a6e368a4 100644
--- a/source/compiler-core/slang-source-map.cpp
+++ b/source/compiler-core/slang-source-map.cpp
@@ -4,7 +4,7 @@ namespace Slang {
 
 void SourceMap::clear()
 {
-    String empty;
+    const String empty;
 
     m_file = empty;
     m_sourceRoot = empty;
@@ -23,6 +23,18 @@ void SourceMap::clear()
     m_slicePool.clear();
 }
 
+void SourceMap::swapWith(ThisType& rhs)
+{
+    m_file.swapWith(rhs.m_file);
+    m_sourceRoot.swapWith(rhs.m_sourceRoot);
+    m_sources.swapWith(rhs.m_sources);
+    m_names.swapWith(rhs.m_names);
+    m_sourcesContent.swapWith(rhs.m_sourcesContent);
+    m_lineStarts.swapWith(rhs.m_lineStarts);
+    m_lineEntries.swapWith(rhs.m_lineEntries);
+    m_slicePool.swapWith(rhs.m_slicePool);
+}
+
 void SourceMap::advanceToLine(Index nextLineIndex)
 {
     const Count currentLineIndex = getGeneratedLineCount() - 1;
diff --git a/source/compiler-core/slang-source-map.h b/source/compiler-core/slang-source-map.h
index f1338508f..e0c8d065a 100644
--- a/source/compiler-core/slang-source-map.h
+++ b/source/compiler-core/slang-source-map.h
@@ -10,9 +10,11 @@
 
 namespace Slang {
 
-class SourceMap : public RefObject
+class SourceMap 
 {
 public:
+    typedef SourceMap ThisType;
+
     SLANG_CLASS_GUID(0x731383ea, 0xe516, 0x4cc3, { 0xa6, 0xcf, 0x37, 0xd2, 0x8c, 0x24, 0x5c, 0x5e });
 
     struct Entry
@@ -66,6 +68,9 @@ public:
         /// Clear the contents of the source map
     void clear();
 
+        /// Swap this with rhs
+    void swapWith(ThisType& rhs);
+
         /// Ctor
     SourceMap():
         m_slicePool(StringSlicePool::Style::Default)
diff --git a/source/core/slang-castable.cpp b/source/core/slang-castable.cpp
index 6b7644bf2..f3c6541dd 100644
--- a/source/core/slang-castable.cpp
+++ b/source/core/slang-castable.cpp
@@ -20,37 +20,6 @@ namespace Slang {
     return castable;
 }
 
-/* !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ObjectCastableAdapter !!!!!!!!!!!!!!!!!!!!!!!!!!! */
-
-void* ObjectCastableAdapter::castAs(const Guid& guid)
-{
-    if (auto intf = getInterface(guid))
-    {
-        return intf;
-    }
-    return getObject(guid);
-}
-
-void* ObjectCastableAdapter::getInterface(const Guid& guid)
-{
-    if (guid == ISlangUnknown::getTypeGuid() ||
-        guid == ICastable::getTypeGuid() ||
-        guid == IObjectCastableAdapter::getTypeGuid())
-    {
-        return static_cast<IObjectCastableAdapter*>(this);
-    }
-    return nullptr;
-}
-
-void* ObjectCastableAdapter::getObject(const Guid& guid)
-{
-    if (guid == m_containedGuid)
-    {
-        return m_contained;
-    }
-    return nullptr;
-}
-
 /* !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! UnknownCastableAdapter !!!!!!!!!!!!!!!!!!!!!!!!!!! */
 
 void* UnknownCastableAdapter::castAs(const Guid& guid)
diff --git a/source/core/slang-castable.h b/source/core/slang-castable.h
index 4f4fdc940..dc6c49a89 100644
--- a/source/core/slang-castable.h
+++ b/source/core/slang-castable.h
@@ -35,18 +35,36 @@ SLANG_FORCE_INLINE T* as(ICastable* castable)
     return nullptr;
 }
 
-/* Adapter interface to make non castable ref counted object usable as ICastable */
-class IObjectCastableAdapter : public ICastable
+/* An interface for boxing values */
+class IBoxValueBase: public ICastable
 {
     SLANG_COM_INTERFACE(0x8b4aad81, 0x4934, 0x4a67, { 0xb2, 0xe2, 0xe9, 0x17, 0xfc, 0x29, 0x12, 0x54 });
 
         /// Get the contained object
-    virtual SLANG_NO_THROW RefObject* SLANG_MCALL getContained() = 0;
+    virtual SLANG_NO_THROW void* SLANG_MCALL getValuePtr() = 0;
         /// Get the guid that represents the contained ref object
-    virtual SLANG_NO_THROW SlangUUID getContainedGuid() = 0;
+    virtual SLANG_NO_THROW SlangUUID SLANG_MCALL getValueTypeGuid() = 0;
 };
 
-class ObjectCastableAdapter : public ComBaseObject, public IObjectCastableAdapter
+template <typename T>
+class IBoxValue : public IBoxValueBase
+{
+    public:
+
+    SLANG_FORCE_INLINE T& get() { return *reinterpret_cast<T*>(getValuePtr()); }
+    SLANG_FORCE_INLINE T* getPtr() { return reinterpret_cast<T*>(getValuePtr()); }
+};
+
+// Cast into a boxed value type
+template <typename T>
+SLANG_FORCE_INLINE IBoxValue<T>* asBoxValue(ICastable* castable)
+{
+    IBoxValueBase* base = as<IBoxValueBase>(castable);
+    return (base && base->getValueTypeGuid() == T::getTypeGuid()) ? static_cast<IBoxValue<T>*>(base) : nullptr;
+}
+
+template <typename T>
+class BoxValue : public ComBaseObject, public IBoxValue<T>
 {
 public:
     SLANG_COM_BASE_IUNKNOWN_ALL
@@ -54,39 +72,59 @@ public:
     // ICastable
     SLANG_NO_THROW void* SLANG_MCALL castAs(const Guid& guid) SLANG_OVERRIDE;
 
-    // IObjectCastableAdapter
-    virtual SLANG_NO_THROW RefObject* SLANG_MCALL getContained() SLANG_OVERRIDE { return m_contained; }
-    virtual SlangUUID getContainedGuid() SLANG_OVERRIDE { return m_containedGuid; }
+    // IBoxValue
+    virtual SLANG_NO_THROW void* SLANG_MCALL getValuePtr() SLANG_OVERRIDE { return &m_value; }
+    virtual SlangUUID SLANG_MCALL getValueTypeGuid() SLANG_OVERRIDE { return T::getTypeGuid(); }
 
-    template <typename T>
-    explicit ObjectCastableAdapter(T* ptr)
-    {
-        m_containedGuid = T::getTypeGuid();
-        m_contained = ptr;
-    }
-    template <typename T>
-    explicit ObjectCastableAdapter(const RefPtr<T>& ptr)
-    {
-        m_containedGuid = T::getTypeGuid();
-        m_contained = ptr;
-    }
+    BoxValue() {}
 
-    ObjectCastableAdapter(RefObject* obj, const Guid& containedGuid) :
-        m_contained(obj),
-        m_containedGuid(containedGuid)
+    explicit BoxValue(const T& rhs):
+        m_value(rhs)
     {
-        SLANG_ASSERT(obj);
     }
 
 protected:
-    void* getInterface(const Guid& guid);
+    void* getInterface(const Guid& guid); 
     void* getObject(const Guid& guid);
-
-    RefPtr<RefObject> m_contained;
-    SlangUUID m_containedGuid;
+    
+    T m_value;
 };
 
+// ------------------------------------------------------------
+template <typename T>
+void* BoxValue<T>::getInterface(const Guid& guid)
+{
+    if (guid == ISlangUnknown::getTypeGuid() ||
+        guid == ICastable::getTypeGuid() ||
+        guid == IBoxValueBase::getTypeGuid())
+    {
+        return static_cast<IBoxValueBase*>(this);
+    }
+    return nullptr;
+}
+
+// ------------------------------------------------------------
+template <typename T>
+void* BoxValue<T>::getObject(const Guid& guid)
+{
+    if (guid == T::getTypeGuid())
+    {
+        return &m_value;
+    }
+    return nullptr;
+}
 
+// ------------------------------------------------------------
+template <typename T>
+void* BoxValue<T>::castAs(const Guid& guid)
+{
+    if (auto ptr = getObject(guid))
+    {
+        return ptr;
+    }
+    return getInterface(guid);
+}
+ 
 /* Adapter interface to make a non castable types work as ICastable */
 class IUnknownCastableAdapter : public ICastable
 {
diff --git a/source/core/slang-dictionary.h b/source/core/slang-dictionary.h
index fffec9640..0839a649c 100644
--- a/source/core/slang-dictionary.h
+++ b/source/core/slang-dictionary.h
@@ -83,6 +83,7 @@ namespace Slang
     public:
         typedef TValue ValueType;
         typedef TKey KeyType;
+		typedef Dictionary ThisType;
 	private:
 		inline int GetProbeOffset(int /*probeId*/) const
 		{
@@ -481,6 +482,10 @@ namespace Slang
 		{
 			return _count;
 		}
+
+			/// Swap this with rhs
+		void swapWith(ThisType& rhs);
+
 	private:
 		template<typename... Args>
 		void Init(const KeyValuePair<TKey, TValue> & kvPair, Args... args)
@@ -543,6 +548,16 @@ namespace Slang
 		}
 	};
 
+	// ---------------------------------------------------------
+	template<typename TKey, typename TValue>
+	void Dictionary<TKey, TValue>::swapWith(ThisType& rhs)
+	{
+		Swap(bucketSizeMinusOne, rhs.bucketSizeMinusOne);
+		Swap(_count, rhs._count);
+		marks.swapWith(rhs.marks);
+		Swap(hashMap, rhs.hashMap);
+	}
+
 	class _DummyClass
 	{};
 
diff --git a/source/core/slang-free-list.cpp b/source/core/slang-free-list.cpp
index 4bada9434..d364b548c 100644
--- a/source/core/slang-free-list.cpp
+++ b/source/core/slang-free-list.cpp
@@ -63,6 +63,22 @@ void FreeList::init(size_t elementSize, size_t alignment, size_t elemsPerBlock)
 	_init(elementSize, alignment, elemsPerBlock);
 }
 
+void FreeList::swapWith(ThisType& rhs)
+{
+	Swap(m_top, rhs.m_top);
+	Swap(m_end, rhs.m_end);
+
+	Swap(m_activeBlocks, rhs.m_activeBlocks);
+	Swap(m_freeBlocks, rhs.m_freeBlocks);
+	
+	Swap(m_freeElements, rhs.m_freeElements);
+	
+	Swap(m_elementSize, rhs.m_elementSize);
+	Swap(m_alignment, rhs.m_alignment);
+	Swap(m_blockSize, rhs.m_blockSize);
+	Swap(m_blockAllocationSize, rhs.m_blockAllocationSize);	
+}
+
 void FreeList::_deallocateBlocks(Block* block)
 {
 	while (block)
diff --git a/source/core/slang-free-list.h b/source/core/slang-free-list.h
index ee0158279..090c13613 100644
--- a/source/core/slang-free-list.h
+++ b/source/core/slang-free-list.h
@@ -69,6 +69,9 @@ class FreeList
 		/// Initialize. If called on an already initialized heap, the heap will be deallocated.
 	void init(size_t elementSize, size_t alignment, size_t elemsPerBlock);
 	
+		/// Swap this with rhs
+	void swapWith(ThisType& rhs);
+
 		/// Default Ctor
 	FreeList() { _init(); }
 		/// Ctor
diff --git a/source/core/slang-memory-arena.cpp b/source/core/slang-memory-arena.cpp
index 6fc6c0c3f..6a13addb6 100644
--- a/source/core/slang-memory-arena.cpp
+++ b/source/core/slang-memory-arena.cpp
@@ -23,6 +23,7 @@ MemoryArena::~MemoryArena()
     reset();
 }
 
+
 MemoryArena::MemoryArena(size_t blockPayloadSize, size_t blockAlignment)
 {
     _initialize(blockPayloadSize, blockAlignment);
@@ -62,6 +63,22 @@ void MemoryArena::_initialize(size_t blockPayloadSize, size_t alignment)
     _resetCurrentBlock();
 }
 
+void MemoryArena::swapWith(ThisType& rhs)
+{
+    Swap(m_start, rhs.m_start);
+    Swap(m_end, rhs.m_end);
+    Swap(m_current, rhs.m_current);
+
+    Swap(m_blockPayloadSize, rhs.m_blockPayloadSize);
+    Swap(m_blockAllocSize, rhs.m_blockAllocSize);
+    Swap(m_blockAlignment, rhs.m_blockAlignment);
+
+    Swap(m_availableBlocks, rhs.m_availableBlocks);
+    Swap(m_usedBlocks, rhs.m_usedBlocks);
+
+    m_blockFreeList.swapWith(rhs.m_blockFreeList);
+}
+
 void MemoryArena::_resetCurrentBlock()
 {
     m_start = nullptr;
diff --git a/source/core/slang-memory-arena.h b/source/core/slang-memory-arena.h
index f63a48413..a947de5a2 100644
--- a/source/core/slang-memory-arena.h
+++ b/source/core/slang-memory-arena.h
@@ -149,6 +149,9 @@ public:
         /// Add a block such that it will be freed when everything else is freed.
     void addExternalBlock(void* data, size_t size);
 
+        // Swap this with rhs 
+    void swapWith(ThisType& rhs);
+
         /// Default Ctor
     MemoryArena();
         /// Construct with block size and alignment. Block alignment must be a power of 2.
diff --git a/source/core/slang-string-slice-pool.cpp b/source/core/slang-string-slice-pool.cpp
index a0af3ba68..45cc811a3 100644
--- a/source/core/slang-string-slice-pool.cpp
+++ b/source/core/slang-string-slice-pool.cpp
@@ -41,6 +41,14 @@ void StringSlicePool::clear()
     }
 }
 
+void StringSlicePool::swapWith(ThisType& rhs)
+{
+    Swap(m_style, rhs.m_style);
+    m_slices.swapWith(rhs.m_slices);
+    m_map.swapWith(rhs.m_map);
+    m_arena.swapWith(rhs.m_arena);
+}
+
 StringSlicePool::Handle StringSlicePool::add(const Slice& slice)
 {
     const Handle* handlePtr = m_map.TryGetValue(slice);
diff --git a/source/core/slang-string-slice-pool.h b/source/core/slang-string-slice-pool.h
index 15d204468..90586a527 100644
--- a/source/core/slang-string-slice-pool.h
+++ b/source/core/slang-string-slice-pool.h
@@ -99,6 +99,9 @@ public:
         /// Get the index of the first added handle
     Index getFirstAddedIndex() const { return m_style == Style::Default ? kDefaultHandlesCount : 0; }
 
+        /// Swap this with rhs
+    void swapWith(ThisType& rhs);
+
         /// Ctor
     explicit StringSlicePool(Style style);
 
diff --git a/source/core/slang-uint-set.h b/source/core/slang-uint-set.h
index 334e7ebe8..f2c573865 100644
--- a/source/core/slang-uint-set.h
+++ b/source/core/slang-uint-set.h
@@ -15,6 +15,7 @@ namespace Slang
 class UIntSet
 {
 public:
+    typedef UIntSet ThisType;
     typedef uint32_t Element;                                   ///< Type that holds the bits to say if value is present
     
     UIntSet() {}
@@ -64,6 +65,9 @@ public:
         /// 
     bool isEmpty() const;
 
+        /// Swap this with rhs
+    void swapWith(ThisType& rhs) { m_buffer.swapWith(rhs.m_buffer); }
+
         /// Store the union of set1 and set2 in outRs
     static void calcUnion(UIntSet& outRs, const UIntSet& set1, const UIntSet& set2);
         /// Store the intersection of set1 and set2 in outRs
diff --git a/source/slang/slang-compiler.cpp b/source/slang/slang-compiler.cpp
index 907f39f48..b5fd27d55 100644
--- a/source/slang/slang-compiler.cpp
+++ b/source/slang/slang-compiler.cpp
@@ -1913,11 +1913,10 @@ namespace Slang
                 auto artifactDesc = ArtifactDesc::make(ArtifactKind::Json, ArtifactPayload::SourceMap, ArtifactStyle::Obfuscated);
 
                 // Create the source map artifact
-                auto sourceMapArtifact = Artifact::create(artifactDesc, sourceMap->m_file.getUnownedSlice());
+                auto sourceMapArtifact = Artifact::create(artifactDesc, sourceMap->get().m_file.getUnownedSlice());
 
                 // Add the repesentation
-                ComPtr<IObjectCastableAdapter> castableAdapter(new ObjectCastableAdapter(sourceMap));
-                sourceMapArtifact->addRepresentation(castableAdapter);
+                sourceMapArtifact->addRepresentation(sourceMap);
 
                 // Associate with the container
                 m_containerArtifact->addAssociated(sourceMapArtifact);
diff --git a/source/slang/slang-emit-source-writer.cpp b/source/slang/slang-emit-source-writer.cpp
index f66f36758..985d0a0bf 100644
--- a/source/slang/slang-emit-source-writer.cpp
+++ b/source/slang/slang-emit-source-writer.cpp
@@ -18,7 +18,7 @@
 
 namespace Slang {
 
-SourceWriter::SourceWriter(SourceManager* sourceManager, LineDirectiveMode lineDirectiveMode, SourceMap* sourceMap)
+SourceWriter::SourceWriter(SourceManager* sourceManager, LineDirectiveMode lineDirectiveMode, IBoxValue<SourceMap>* sourceMap)
 {
     m_sourceMap = sourceMap;
     m_lineDirectiveMode = lineDirectiveMode;
@@ -360,23 +360,25 @@ void SourceWriter::_updateSourceMap(const HumaneSourceLoc& sourceLocation)
     if (sourceLocation.line <= 0)
         return;
 
+    auto sourceMap = m_sourceMap->getPtr();
+
     // We need to work out the current column in the generated (ie being written) output
     Index generatedLineIndex, generatedColumnIndex;
     _calcLocation(generatedLineIndex, generatedColumnIndex);
 
     // Advance to the current output line
-    m_sourceMap->advanceToLine(generatedLineIndex);
+    sourceMap->advanceToLine(generatedLineIndex);
 
     // Add the entry into the map, mapping back to the original source
     SourceMap::Entry entry;
     entry.init();
 
-    entry.sourceFileIndex = m_sourceMap->getSourceFileIndex(sourceLocation.pathInfo.getName().getUnownedSlice());
+    entry.sourceFileIndex = sourceMap->getSourceFileIndex(sourceLocation.pathInfo.getName().getUnownedSlice());
     entry.sourceLine = sourceLocation.line - 1;
     entry.sourceColumn = sourceLocation.column - 1;
     entry.generatedColumn = generatedColumnIndex;
     
-    m_sourceMap->addEntry(entry);
+    sourceMap->addEntry(entry);
 }
 
 void SourceWriter::_emitLineDirectiveIfNeeded(const HumaneSourceLoc& sourceLocation)
diff --git a/source/slang/slang-emit-source-writer.h b/source/slang/slang-emit-source-writer.h
index c47b5f5fa..b64eb052a 100644
--- a/source/slang/slang-emit-source-writer.h
+++ b/source/slang/slang-emit-source-writer.h
@@ -6,7 +6,7 @@
 
 #include "slang-compiler.h"
 #include "../compiler-core/slang-source-map.h"
-
+#include "../core/slang-castable.h"
 
 namespace Slang
 {
@@ -75,10 +75,10 @@ public:
     SourceManager* getSourceManager() const { return m_sourceManager; }
 
         /// Get the associated source map. If source map tracking is not required, can return nullptr.
-    SourceMap* getSourceMap() const { return m_sourceMap; }
+    IBoxValue<SourceMap>* getSourceMap() const { return m_sourceMap; }
 
         /// Ctor
-    SourceWriter(SourceManager* sourceManager, LineDirectiveMode lineDirectiveMode, SourceMap* sourceMap);
+    SourceWriter(SourceManager* sourceManager, LineDirectiveMode lineDirectiveMode, IBoxValue<SourceMap>* sourceMap);
 
 protected:
     void _emitTextSpan(char const* textBegin, char const* textEnd);
@@ -140,7 +140,7 @@ protected:
     Dictionary<String, int> m_mapGLSLSourcePathToID;
     int m_glslSourceIDCount = 0;
 
-    RefPtr<SourceMap> m_sourceMap;
+    ComPtr<IBoxValue<SourceMap>> m_sourceMap;
 
     LineDirectiveMode m_lineDirectiveMode;
 };
diff --git a/source/slang/slang-emit.cpp b/source/slang/slang-emit.cpp
index 67a4c4610..f9284d001 100644
--- a/source/slang/slang-emit.cpp
+++ b/source/slang/slang-emit.cpp
@@ -969,12 +969,12 @@ SlangResult CodeGenContext::emitEntryPointsSourceFromIR(ComPtr<IArtifact>& outAr
         lineDirectiveMode = LineDirectiveMode::GLSL;
     }
 
-    RefPtr<SourceMap> sourceMap;
+    ComPtr<IBoxValue<SourceMap>> sourceMap;
 
     // If SourceMap is enabled, we create one and associate it with the sourceWriter
     if (targetRequest->getLinkage()->m_generateSourceMap)
     {
-        sourceMap = new SourceMap;
+        sourceMap = new BoxValue<SourceMap>;
     }
 
     SourceWriter sourceWriter(sourceManager, lineDirectiveMode, sourceMap );
@@ -1154,8 +1154,7 @@ SlangResult CodeGenContext::emitEntryPointsSourceFromIR(ComPtr<IArtifact>& outAr
     {
         auto sourceMapArtifact = ArtifactUtil::createArtifact(ArtifactDesc::make(ArtifactKind::Json, ArtifactPayload::SourceMap, ArtifactStyle::None));
 
-        ComPtr<IObjectCastableAdapter> castableAdapter(new ObjectCastableAdapter(sourceMap));
-        sourceMapArtifact->addRepresentation(castableAdapter);
+        sourceMapArtifact->addRepresentation(sourceMap);
 
         artifact->addAssociated(sourceMapArtifact);
     }
diff --git a/source/slang/slang-ir-obfuscate-loc.cpp b/source/slang/slang-ir-obfuscate-loc.cpp
index 9a2f15fa4..7bb4bef7d 100644
--- a/source/slang/slang-ir-obfuscate-loc.cpp
+++ b/source/slang/slang-ir-obfuscate-loc.cpp
@@ -7,6 +7,8 @@
 #include "../core/slang-hash.h"
 #include "../core/slang-char-util.h"
 
+#include "../core/slang-castable.h"
+
 namespace Slang
 {
 
@@ -247,7 +249,10 @@ SlangResult obfuscateModuleLocs(IRModule* module, SourceManager* sourceManager)
     // We can now create a map. The locs are in order in entries, so that should make lookup easier.
     // This doesn't "leak" anything as the obfuscated loc map is not distributed.
 
-    RefPtr<SourceMap> sourceMap = new SourceMap;
+    ComPtr<IBoxValue<SourceMap>> boxedSourceMap(new BoxValue<SourceMap>);
+
+    auto sourceMap = boxedSourceMap->getPtr();
+
     sourceMap->m_file = obfusctatedPathInfo.getName();
 
     // Set up entries one per line
@@ -349,10 +354,10 @@ SlangResult obfuscateModuleLocs(IRModule* module, SourceManager* sourceManager)
     }
 
     // Associate the sourceMap with the obfuscated file
-    obfuscatedFile->setSourceMap(sourceMap);
+    obfuscatedFile->setSourceMap(boxedSourceMap);
 
     // Set the obfuscated map onto the module
-    module->setObfuscatedSourceMap(sourceMap);
+    module->setObfuscatedSourceMap(boxedSourceMap);
 
     return SLANG_OK;
 }
diff --git a/source/slang/slang-ir.h b/source/slang/slang-ir.h
index 78069a122..a53fe0092 100644
--- a/source/slang/slang-ir.h
+++ b/source/slang/slang-ir.h
@@ -2034,8 +2034,8 @@ public:
     SLANG_FORCE_INLINE IRModuleInst* getModuleInst() const { return m_moduleInst;  }
     SLANG_FORCE_INLINE MemoryArena& getMemoryArena() { return m_memoryArena; }
 
-    SLANG_FORCE_INLINE SourceMap* getObfuscatedSourceMap() const { return m_obfuscatedSourceMap; }
-    SLANG_FORCE_INLINE void setObfuscatedSourceMap(SourceMap* sourceMap) { m_obfuscatedSourceMap = sourceMap; }
+    SLANG_FORCE_INLINE IBoxValue<SourceMap>* getObfuscatedSourceMap() const { return m_obfuscatedSourceMap; }
+    SLANG_FORCE_INLINE void setObfuscatedSourceMap(IBoxValue<SourceMap>* sourceMap) { m_obfuscatedSourceMap = sourceMap; }
 
     IRDeduplicationContext* getDeduplicationContext() const { return &m_deduplicationContext; }
 
@@ -2105,7 +2105,7 @@ private:
     mutable IRDeduplicationContext m_deduplicationContext;
 
         /// Holds the obfuscated source map for this module if applicable
-    RefPtr<SourceMap> m_obfuscatedSourceMap;
+    ComPtr<IBoxValue<SourceMap>> m_obfuscatedSourceMap;
 };
 
 struct IRSpecializationDictionaryItem : public IRInst
diff --git a/source/slang/slang.cpp b/source/slang/slang.cpp
index bedfb1161..6b2814ca7 100644
--- a/source/slang/slang.cpp
+++ b/source/slang/slang.cpp
@@ -2385,7 +2385,7 @@ void FrontEndCompileRequest::generateIR()
         if (useSerialIRBottleneck)
         {
             // Keep the obfuscated source map (if there is one)
-            RefPtr<SourceMap> obfuscatedSourceMap = irModule->getObfuscatedSourceMap();
+            ComPtr<IBoxValue<SourceMap>> obfuscatedSourceMap(irModule->getObfuscatedSourceMap());
 
             IRSerialData serialData;
             {
@@ -4884,9 +4884,9 @@ SlangResult _addLibraryReference(EndToEndCompileRequest* req, IArtifact* artifac
             {
                 ComPtr<ICastable> castable;
                 SLANG_RETURN_ON_FAIL(associated->getOrCreateRepresentation(SourceMap::getTypeGuid(), ArtifactKeep::Yes, castable.writeRef()));
-
-                auto sourceMap = as<SourceMap>(castable);
-
+                auto sourceMap = asBoxValue<SourceMap>(castable);
+                SLANG_ASSERT(sourceMap);
+                
                 // I guess we add to all ir modules?
 
                 for (auto irModule : library->m_modules)