Fix lowering logic around imported modules. (shader-slang#3668)

* Fix lowering logic around imported modules.

* Use actual source loc when emitting SPIRV.

source/slang/slang-lower-to-ir.cpp

@@ -656,6 +656,16 @@ bool isFromStdLib(Decl* decl)
     return false;
 }
 
+bool isDeclInDifferentModule(IRGenContext* context, Decl* decl)
+{
+    return getModuleDecl(decl) != context->getMainModuleDecl();
+}
+
+bool isForceInlineEarly(Decl* decl)
+{
+    return decl->hasModifier<UnsafeForceInlineEarlyAttribute>();
+}
+
 bool isImportedDecl(IRGenContext* context, Decl* decl, bool& outIsExplicitExtern)
 {
     // If the declaration has the extern attribute then it must be imported
@@ -6295,7 +6305,10 @@ void maybeEmitDebugLine(IRGenContext* context, StmtLoweringVisitor& visitor, Stm
     IRInst* debugSourceInst = nullptr;
     if (context->shared->mapSourceFileToDebugSourceInst.tryGetValue(source, debugSourceInst))
     {
-        auto humaneLoc = context->getLinkage()->getSourceManager()->getHumaneLoc(stmt->loc, SourceLocType::Emit);
+        // When working with RenderDoc, we need to use actual source loc instead of the nominal one,
+        // since RenderDoc has the builtin support to split a source file into multiple files based on
+        // line directives in the file.
+        auto humaneLoc = context->getLinkage()->getSourceManager()->getHumaneLoc(stmt->loc, SourceLocType::Actual);
         visitor.startBlockIfNeeded(stmt);
         context->irBuilder->emitDebugLine(debugSourceInst, humaneLoc.line, humaneLoc.line, humaneLoc.column, humaneLoc.column + 1);
     }
@@ -9131,6 +9144,10 @@ struct DeclLoweringVisitor : DeclVisitor<DeclLoweringVisitor, LoweredValInfo>
             // In Slang we currently try not to support forward declarations
             // (although we might have to give in eventually), so
             // this case should really only occur for builtin declarations.
+        }
+        else if (isDeclInDifferentModule(context, decl) && !isForceInlineEarly(decl))
+        {
+
         }
         else if (emitBody)
         {