1 files changed, 60 insertions, 12 deletions

diff --git a/source/slang/lower-to-ir.cpp b/source/slang/lower-to-ir.cpp
index b53bb8ebb..e5d62d257 100644
--- a/source/slang/lower-to-ir.cpp
+++ b/source/slang/lower-to-ir.cpp
@@ -4793,21 +4793,23 @@ struct DeclLoweringVisitor : DeclVisitor<DeclLoweringVisitor, LoweredValInfo>
         // A user-defined variable declaration will usually turn into
         // an `alloca` operation for the variable's storage,
         // plus some code to initialize it and then store to the variable.
-        //
-        // TODO: we may want to special-case things when the variable's
-        // type, qualifiers, or context mark it as something that can't
-        // be mutable (or even do some limited dataflow pass to check
-        // which variables ever get assigned) so that we can directly
-        // emit an SSA value in this common case.
-        //
 
         IRType* varType = lowerType(context, decl->getType());
 
-        // TODO: If the variable is marked `static` then we need to
-        // deal with it specially: we should move its allocation out
-        // to the global scope, and then we have to deal with its
-        // initializer expression a bit carefully (it should only
-        // be initialized on-demand at its first use).
+        // As a special case, an immutable local variable with an
+        // initializer can just lower to the SSA value of its initializer.
+        //
+        if(as<LetDecl>(decl))
+        {
+            if(auto initExpr = decl->initExpr)
+            {
+                auto initVal = lowerRValueExpr(context, initExpr);
+                initVal = materialize(context, initVal);
+                setGlobalValue(context, decl, initVal);
+                return initVal;
+            }
+        }
+
 
         LoweredValInfo varVal = createVar(context, varType, decl);
 
@@ -6187,6 +6189,30 @@ static void lowerProgramEntryPointToIR(
     {
         builder->addExportDecoration(loweredEntryPointFunc, getMangledName(entryPointFuncDeclRef).getUnownedSlice());
     }
+
+    // We may have shader parameters of interface/existential type,
+    // which need us to supply concrete type information for specialization.
+    //
+    auto existentialSlotCount = entryPoint->getExistentialSlotCount();
+    if( existentialSlotCount )
+    {
+        List<IRInst*> existentialSlotArgs;
+        for( UInt ii = 0; ii < existentialSlotCount; ++ii )
+        {
+            auto arg = entryPoint->getExistentialSlotArg(ii);
+
+            auto irArgType = lowerType(context, arg.type);
+            auto irWitnessTable = lowerSimpleVal(context, arg.witness);
+
+            existentialSlotArgs.Add(irArgType);
+            existentialSlotArgs.Add(irWitnessTable);
+        }
+
+        builder->addBindExistentialSlotsDecoration(loweredEntryPointFunc, existentialSlotArgs.Count(), existentialSlotArgs.Buffer());
+    }
+
+
+
 }
 
     /// Ensure that `decl` and all relevant declarations under it get emitted.
@@ -6394,6 +6420,28 @@ RefPtr<IRModule> generateIRForProgram(
         }
     }
 
+    // We may have shader parameters of interface/existential type,
+    // which need us to supply concrete type information for specialization.
+    //
+    auto existentialSlotCount = program->getExistentialSlotCount();
+    if( existentialSlotCount )
+    {
+        List<IRInst*> existentialSlotArgs;
+        for( UInt ii = 0; ii < existentialSlotCount; ++ii )
+        {
+            auto arg = program->getExistentialSlotArg(ii);
+
+            auto irArgType = lowerType(context, arg.type);
+            auto irWitnessTable = lowerSimpleVal(context, arg.witness);
+
+            existentialSlotArgs.Add(irArgType);
+            existentialSlotArgs.Add(irWitnessTable);
+        }
+
+        builder->emitBindGlobalExistentialSlots(existentialSlotArgs.Count(), existentialSlotArgs.Buffer());
+    }
+
+
     // TODO: Should we apply any of the validation or
     // mandatory optimization passes here?