Add referenced modules as libraries when creating a session (#6569)

In the legacy compile request based API, the referenced modules are added to the request's
linkage libraries as part of compiler option parsing.
In the non-legacy compilation API, the argument parsing creates a temprary compile request
and so those libraries only survive as options.

This change will look for such options when creating an ISession object, and again add the
referenced modules to the libraries of the new linkage that's contained in the ISession
object.

This is done in two steps:

1. Factor out a helper to create a referenced module artifact in the same way as it's done
   during legacy option parsing.
2. Use the helper function to create artifacts to add to the linkage libararies, when the
   session is created.

This helps to address issue #4760, because it enables passing in downstream modules via
options, as is required for the following tests:

tests/library/library-test.slang.2 (dx12)
tests/library/export-test.slang.2 (dx12)

3 files changed, 49 insertions, 4 deletions

diff --git a/source/slang/slang-options.cpp b/source/slang/slang-options.cpp
index ed2424224..72756d360 100644
--- a/source/slang/slang-options.cpp
+++ b/source/slang/slang-options.cpp
@@ -1748,13 +1748,17 @@ SlangResult OptionsParser::_expectInt(const CommandLineArg& initArg, Int& outInt
     return SLANG_OK;
 }
 
-SlangResult OptionsParser::addReferencedModule(String path, SourceLoc loc, bool includeEntryPoint)
+SlangResult createArtifactFromReferencedModule(
+    String path,
+    SourceLoc loc,
+    DiagnosticSink* sink,
+    IArtifact** outArtifact)
 {
     auto desc = ArtifactDescUtil::getDescFromPath(path.getUnownedSlice());
 
     if (desc.kind == ArtifactKind::Unknown)
     {
-        m_sink->diagnose(loc, Diagnostics::unknownLibraryKind, Path::getPathExt(path));
+        sink->diagnose(loc, Diagnostics::unknownLibraryKind, Path::getPathExt(path));
         return SLANG_FAIL;
     }
 
@@ -1772,7 +1776,7 @@ SlangResult OptionsParser::addReferencedModule(String path, SourceLoc loc, bool
 
     if (!ArtifactDescUtil::isLinkable(desc))
     {
-        m_sink->diagnose(loc, Diagnostics::kindNotLinkable, Path::getPathExt(path));
+        sink->diagnose(loc, Diagnostics::kindNotLinkable, Path::getPathExt(path));
         return SLANG_FAIL;
     }
 
@@ -1803,11 +1807,20 @@ SlangResult OptionsParser::addReferencedModule(String path, SourceLoc loc, bool
             nullptr);
         if (!fileRep->exists())
         {
-            m_sink->diagnose(loc, Diagnostics::libraryDoesNotExist, path);
+            sink->diagnose(loc, Diagnostics::libraryDoesNotExist, path);
             return SLANG_FAIL;
         }
     }
     artifact->addRepresentation(fileRep);
+    *outArtifact = artifact.detach();
+    return SLANG_OK;
+}
+
+SlangResult OptionsParser::addReferencedModule(String path, SourceLoc loc, bool includeEntryPoint)
+{
+    ComPtr<IArtifact> artifact;
+    SLANG_RETURN_ON_FAIL(
+        createArtifactFromReferencedModule(path, loc, m_sink, artifact.writeRef()));
 
     SLANG_RETURN_ON_FAIL(_addLibraryReference(m_requestImpl, path, artifact, includeEntryPoint));
     for (Index i = m_rawTranslationUnits.getCount(); i < m_requestImpl->getTranslationUnitCount();
diff --git a/source/slang/slang-options.h b/source/slang/slang-options.h
index 3924ccb1c..7ee861879 100644
--- a/source/slang/slang-options.h
+++ b/source/slang/slang-options.h
@@ -2,12 +2,15 @@
 #ifndef SLANG_OPTIONS_H
 #define SLANG_OPTIONS_H
 
+#include "../compiler-core/slang-source-loc.h"
 #include "../core/slang-basic.h"
 
 namespace Slang
 {
 
 struct CommandOptions;
+class DiagnosticSink;
+class IArtifact;
 
 UnownedStringSlice getCodeGenTargetName(SlangCompileTarget target);
 
@@ -20,5 +23,11 @@ enum class Stage : SlangUInt32;
 
 SlangSourceLanguage findSourceLanguageFromPath(const String& path, Stage& outImpliedStage);
 
+SlangResult createArtifactFromReferencedModule(
+    String path,
+    SourceLoc loc,
+    DiagnosticSink* sink,
+    IArtifact** outArtifact);
+
 } // namespace Slang
 #endif
diff --git a/source/slang/slang.cpp b/source/slang/slang.cpp
index 8dfaf115e..18368b33b 100644
--- a/source/slang/slang.cpp
+++ b/source/slang/slang.cpp
@@ -861,6 +861,29 @@ Session::createSession(slang::SessionDesc const& inDesc, slang::ISession** outSe
             Math::Max(linkageDebugInfoLevel, target->getOptionSet().getDebugInfoLevel());
     linkage->m_optionSet.set(CompilerOptionName::DebugInformation, linkageDebugInfoLevel);
 
+    // Add any referenced modules to the linkage
+    for (auto& option : linkage->m_optionSet.options)
+    {
+        if (option.key != CompilerOptionName::ReferenceModule)
+            continue;
+        for (auto& path : option.value)
+        {
+            DiagnosticSink sink;
+            ComPtr<IArtifact> artifact;
+            SlangResult result = createArtifactFromReferencedModule(
+                path.stringValue,
+                SourceLoc{},
+                &sink,
+                artifact.writeRef());
+            if (SLANG_FAILED(result))
+            {
+                sink.diagnose(SourceLoc{}, Diagnostics::unableToReadFile, path.stringValue);
+                return result;
+            }
+            linkage->m_libModules.add(artifact);
+        }
+    }
+
     *outSession = asExternal(linkage.detach());
     return SLANG_OK;
 }