Merge pull request shader-slang#367 from csyonghe/extension2

Support transitive interfaces

Author: csyonghe

source/slang/ir.cpp

@@ -3690,12 +3690,12 @@ namespace Slang
         cloneFunctionCommon(context, clonedFunc, originalFunc);
 
         // for now, clone all unreferenced witness tables
-        /*for (auto gv = context->getOriginalModule()->getFirstGlobalValue();
+        for (auto gv = context->getOriginalModule()->getFirstGlobalValue();
             gv; gv = gv->getNextValue())
         {
             if (gv->op == kIROp_witness_table)
                 cloneGlobalValue(context, (IRWitnessTable*)gv);
-        }*/
+        }
 
         // We need to attach the layout information for
         // the entry point to this declaration, so that

source/slang/lookup.cpp

@@ -297,6 +297,23 @@ void DoLocalLookupImpl(
                 session,
                 name, extDeclRef, request, result, inBreadcrumbs);
         }
+
+    }
+    // for interface decls, also lookup in the base interfaces
+    if (request.semantics)
+    {
+        if (auto interfaceDeclRef = containerDeclRef.As<InterfaceDecl>())
+        {
+            auto baseInterfaces = getMembersOfType<InheritanceDecl>(interfaceDeclRef);
+            for (auto inheritanceDeclRef : baseInterfaces)
+            {
+                auto baseType = inheritanceDeclRef.getDecl()->base.type.As<DeclRefType>();
+                SLANG_ASSERT(baseType);
+                int diff = 0;
+                auto baseInterfaceDeclRef = baseType->declRef.SubstituteImpl(interfaceDeclRef.substitutions, &diff);
+                DoLocalLookupImpl(session, name, baseInterfaceDeclRef.As<ContainerDecl>(), request, result, inBreadcrumbs);
+            }
+        }
     }
 }
 

source/slang/lower-to-ir.cpp

@@ -2781,6 +2781,30 @@ struct DeclLoweringVisitor : DeclVisitor<DeclLoweringVisitor, LoweredValInfo>
         return LoweredValInfo();
     }
 
+    void walkInheritanceHierarchyAndCreateWitnessTableCopies(IRWitnessTable* witnessTable, Type* subType, InheritanceDecl* inheritanceDecl)
+    {
+        auto baseDeclRef = inheritanceDecl->base.type.As<DeclRefType>();
+        if (auto baseInterfaceDeclRef = baseDeclRef->declRef.As<InterfaceDecl>())
+        {
+            for (auto subInheritanceDeclRef : getMembersOfType<InheritanceDecl>(baseInterfaceDeclRef))
+            {
+                auto cpyMangledName = getMangledNameForConformanceWitness(subType, subInheritanceDeclRef.getDecl()->getSup().type);
+                if (!witnessTablesDictionary.ContainsKey(cpyMangledName))
+                {
+                    auto cpyTable = context->irBuilder->createWitnessTable();
+                    cpyTable->mangledName = cpyMangledName;
+                    context->irBuilder->createWitnessTableEntry(witnessTable,
+                        context->irBuilder->getDeclRefVal(subInheritanceDeclRef), cpyTable);
+                    cpyTable->entries = witnessTable->entries;
+                    witnessTablesDictionary.Add(cpyMangledName, cpyTable);
+                    walkInheritanceHierarchyAndCreateWitnessTableCopies(witnessTable, subType, subInheritanceDeclRef.getDecl());
+                }
+            }
+        }
+    }
+
+    Dictionary<String, IRWitnessTable*> witnessTablesDictionary;
+
     LoweredValInfo visitInheritanceDecl(InheritanceDecl* inheritanceDecl)
     {
         // Construct a type for the parent declaration.
@@ -2817,6 +2841,8 @@ struct DeclLoweringVisitor : DeclVisitor<DeclLoweringVisitor, LoweredValInfo>
         // conformance of the type to its super-type.
         auto witnessTable = context->irBuilder->createWitnessTable();
         witnessTable->mangledName = mangledName;
+        
+        witnessTablesDictionary.Add(mangledName, witnessTable);
 
         if (parentDecl->ParentDecl)
             witnessTable->genericDecl = dynamic_cast<GenericDecl*>(parentDecl->ParentDecl);
@@ -2850,6 +2876,7 @@ struct DeclLoweringVisitor : DeclVisitor<DeclLoweringVisitor, LoweredValInfo>
         }
 
         witnessTable->moveToEnd();
+        walkInheritanceHierarchyAndCreateWitnessTableCopies(witnessTable, type, inheritanceDecl);
 
         // A direct reference to this inheritance relationship (e.g.,
         // as a subtype witness) will take the form of a reference to

tests/compute/transitive-interface.slang

@@ -0,0 +1,66 @@
+//TEST(compute):COMPARE_COMPUTE:-xslang -use-ir
+//TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):dxbinding(0),glbinding(0),out
+
+RWStructuredBuffer<float> outputBuffer;
+
+interface IAdd
+{
+    float addf(float u, float v);
+}
+
+interface ISub
+{
+    float subf(float u, float v);
+}
+
+interface IAddAndSub : IAdd, ISub
+{
+}
+
+struct Simple : IAddAndSub
+{
+    float addf(float u, float v)
+    {
+        return u+v;
+    }
+    float subf(float u, float v)
+    {
+        return u-v;
+    }
+};
+
+float testAdd<T:IAdd>(T t)
+{
+    return t.addf(1.0, 1.0);
+}
+
+interface IAssoc
+{
+    associatedtype AT : IAdd;
+}
+
+struct AssocImpl : IAssoc
+{
+    typedef Simple AT;
+};
+
+float testAdd2<T:IAssoc>(T assoc)
+{
+    T.AT obj;
+    return obj.addf(1.0, 1.0);
+}
+
+float testSub<T:ISub>(T t, float base)
+{
+    return t.subf(base, 1.0);
+}
+
+[numthreads(4, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    AssocImpl s;
+	float outVal = testAdd2(s);
+    Simple s1;
+    outVal += testSub(s1, outVal);
+	outputBuffer[dispatchThreadID.x] = outVal;
+}

tests/compute/transitive-interface.slang.expected.txt

@@ -0,0 +1,4 @@
+3F800000
+3F800000
+3F800000
+3F800000