fixup global generic parameters

1. simplify RoundUpToAlignment()
2. add new a render-compute test case to cover the situation where the entry-point interface (parameter/return types of an entry-point function) is dependent on the global generic type.
3. initial fixes to get this test case to compile (but is not producing correct HLSL output yet)

5 files changed, 66 insertions, 15 deletions

diff --git a/source/slang/ir.cpp b/source/slang/ir.cpp
index 2d3127a61..f5f52e08a 100644
--- a/source/slang/ir.cpp
+++ b/source/slang/ir.cpp
@@ -3103,10 +3103,22 @@ namespace Slang
     IRGlobalVar* cloneGlobalVar(IRSpecContext* context, IRGlobalVar* originalVar);
     IRFunc* cloneFunc(IRSpecContext* context, IRFunc* originalFunc);
     IRWitnessTable* cloneWitnessTable(IRSpecContext* context, IRWitnessTable* originalVar);
+    RefPtr<Substitutions> cloneSubstitutions(
+        IRSpecContext*  context,
+        Substitutions*  subst);
 
     RefPtr<Type> IRSpecContext::maybeCloneType(Type* originalType)
     {
-        return originalType->Substitute(subst).As<Type>();
+        auto rsType = originalType->Substitute(subst).As<Type>();
+        if (auto declRefType = rsType.As<DeclRefType>())
+        {
+            if (subst)
+            {
+                auto newSubst = cloneSubstitutions(this, subst);
+                insertSubstAtBottom(declRefType->declRef.substitutions, newSubst);
+            }
+        }
+        return rsType;
     }
 
     IRValue* IRSpecContext::maybeCloneValue(IRValue* originalValue)
@@ -3243,6 +3255,15 @@ namespace Slang
             newSubst->outer = cloneSubstitutions(context, subst->outer);
             return newSubst;
         }
+        else if (auto genTypeSubst = dynamic_cast<GlobalGenericParamSubstitution*>(subst))
+        {
+            RefPtr<GlobalGenericParamSubstitution> newSubst = new GlobalGenericParamSubstitution();
+            newSubst->actualType = genTypeSubst->actualType;
+            newSubst->paramDecl = genTypeSubst->paramDecl;
+            newSubst->witnessTables = genTypeSubst->witnessTables;
+            newSubst->outer = cloneSubstitutions(context, subst->outer);
+            return newSubst;
+        }
         else
             SLANG_UNREACHABLE("unimplemented cloneSubstitution");
         UNREACHABLE_RETURN(nullptr);
diff --git a/source/slang/parameter-binding.cpp b/source/slang/parameter-binding.cpp
index 836ed254f..0daa2abc7 100644
--- a/source/slang/parameter-binding.cpp
+++ b/source/slang/parameter-binding.cpp
@@ -1425,6 +1425,16 @@ static RefPtr<TypeLayout> processEntryPointParameter(
 
             return structLayout;
         }
+        else if (auto globalGenericParam = declRef.As<GlobalGenericParamDecl>())
+        {
+            auto genParamTypeLayout = new GenericParamTypeLayout();
+            // we should have already populated ProgramLayout::genericEntryPointParams list at this point,
+            // so we can find the index of this generic param decl in the list
+            genParamTypeLayout->type = type;
+            genParamTypeLayout->paramIndex = findGenericParam(context->shared->programLayout->globalGenericParams, globalGenericParam.getDecl());
+            genParamTypeLayout->findOrAddResourceInfo(LayoutResourceKind::GenericResource)->count++;
+            return genParamTypeLayout;
+        }
         else
         {
             SLANG_UNEXPECTED("unhandled type kind");
@@ -1442,7 +1452,8 @@ static RefPtr<TypeLayout> processEntryPointParameter(
 
 static void collectEntryPointParameters(
     ParameterBindingContext*        context,
-    EntryPointRequest*              entryPoint)
+    EntryPointRequest*              entryPoint,
+    Substitutions*                  typeSubst)
 {
     FuncDecl* entryPointFuncDecl = entryPoint->decl;
     if (!entryPointFuncDecl)
@@ -1507,7 +1518,7 @@ static void collectEntryPointParameters(
         auto paramTypeLayout = processEntryPointParameterWithPossibleSemantic(
             context,
             paramDecl.Ptr(),
-            paramDecl->type.type,
+            paramDecl->type.type->Substitute(typeSubst).As<Type>(),
             state,
             paramVarLayout);
 
@@ -1539,7 +1550,7 @@ static void collectEntryPointParameters(
         auto resultTypeLayout = processEntryPointParameterWithPossibleSemantic(
             context,
             entryPointFuncDecl,
-            resultType,
+            resultType->Substitute(typeSubst).As<Type>(),
             state,
             resultLayout);
 
@@ -1632,7 +1643,7 @@ static void collectParameters(
         for( auto& entryPoint : translationUnit->entryPoints )
         {
             context->stage = entryPoint->profile.GetStage();
-            collectEntryPointParameters(context, entryPoint.Ptr());
+            collectEntryPointParameters(context, entryPoint.Ptr(), nullptr);
         }
     }
 
@@ -1891,13 +1902,7 @@ RefPtr<ProgramLayout> specializeProgramLayout(
     newProgramLayout = new ProgramLayout();
     newProgramLayout->bindingForHackSampler = programLayout->bindingForHackSampler;
     newProgramLayout->hackSamplerVar = programLayout->hackSamplerVar;
-    for (auto & entryPoint : programLayout->entryPoints)
-    {
-        RefPtr<EntryPointLayout> newEntryPoint = new EntryPointLayout(*entryPoint);
-        // TODO: for now just copy existing entry point layouts, but we eventually need to
-        // specialize these as well...
-        newProgramLayout->entryPoints.Add(newEntryPoint);
-    }
+    newProgramLayout->globalGenericParams = programLayout->globalGenericParams;
 
     List<RefPtr<TypeLayout>> paramTypeLayouts;
     auto globalStructLayout = getGlobalStructLayout(programLayout);
@@ -1919,7 +1924,7 @@ RefPtr<ProgramLayout> specializeProgramLayout(
     SharedParameterBindingContext sharedContext;
     sharedContext.compileRequest = targetReq->compileRequest;
     sharedContext.defaultLayoutRules = layoutContext.getRulesFamily();
-    sharedContext.programLayout = programLayout;
+    sharedContext.programLayout = newProgramLayout;
 
     // Create a sub-context to collect parameters that get
     // declared into the global scope
@@ -1928,6 +1933,15 @@ RefPtr<ProgramLayout> specializeProgramLayout(
     context.translationUnit = nullptr;
     context.layoutContext = layoutContext;
     
+    
+    for (auto & translationUnit : targetReq->compileRequest->translationUnits)
+    {
+        for (auto & entryPoint : translationUnit->entryPoints)
+        {
+            collectEntryPointParameters(&context, entryPoint, typeSubst);
+        }
+    }
+
     auto constantBufferRules = context.getRulesFamily()->getConstantBufferRules();
     structLayout->rules = constantBufferRules;
 
diff --git a/source/slang/syntax.cpp b/source/slang/syntax.cpp
index e43dd9074..badfaea4f 100644
--- a/source/slang/syntax.cpp
+++ b/source/slang/syntax.cpp
@@ -1709,7 +1709,22 @@ void Type::accept(IValVisitor* visitor, void* extra)
         return sb.ProduceString();
     }
 
-
+    void insertSubstAtBottom(RefPtr<Substitutions> & substHead, RefPtr<Substitutions> substToInsert)
+    {
+        if (!substHead)
+        {
+            substHead = substToInsert;
+            return;
+        }
+        auto subst = substHead;
+        RefPtr<Substitutions> lastSubst = subst;
+        while (subst->outer)
+        {
+            lastSubst = subst;
+            subst = subst->outer;
+        }
+        lastSubst->outer = substToInsert;
+    }
 
     void insertSubstAtTop(DeclRefBase & declRef, RefPtr<Substitutions> substToInsert)
     {
diff --git a/source/slang/syntax.h b/source/slang/syntax.h
index b4d550ef5..f3690d9ae 100644
--- a/source/slang/syntax.h
+++ b/source/slang/syntax.h
@@ -1156,6 +1156,7 @@ namespace Slang
         Session* session,
         Decl*   decl);
 
+    void insertSubstAtBottom(RefPtr<Substitutions> & substHead, RefPtr<Substitutions> substToInsert);
     RefPtr<ThisTypeSubstitution> getNewThisTypeSubst(DeclRefBase & declRef);
     RefPtr<ThisTypeSubstitution> getThisTypeSubst(DeclRefBase & declRef, bool insertSubstEntry);
     void removeSubstitution(DeclRefBase & declRef, RefPtr<Substitutions> subst);
diff --git a/source/slang/type-layout.h b/source/slang/type-layout.h
index 4ce6dc355..07530bdfc 100644
--- a/source/slang/type-layout.h
+++ b/source/slang/type-layout.h
@@ -676,7 +676,7 @@ createStructuredBufferTypeLayout(
     RefPtr<Type>                structuredBufferType,
     RefPtr<Type>                elementType);
 
-
+int findGenericParam(List<RefPtr<GenericParamLayout>> & genericParameters, GlobalGenericParamDecl * decl);
 //
 
 }