[clang][SYCL] Allow structs as free function kernel arguments

clang/lib/Sema/SemaSYCL.cpp

@@ -1443,9 +1443,12 @@ class KernelObjVisitor {
                   HandlerTys &...Handlers) {
     if (isSyclSpecialType(ParamTy, SemaSYCLRef))
       KP_FOR_EACH(handleOtherType, Param, ParamTy);
-    else if (ParamTy->isStructureOrClassType())
-      KP_FOR_EACH(handleOtherType, Param, ParamTy);
-    else if (ParamTy->isUnionType())
+    else if (ParamTy->isStructureOrClassType()) {
+      if (KP_FOR_EACH(handleStructType, Param, ParamTy)) {
+        CXXRecordDecl *RD = ParamTy->getAsCXXRecordDecl();
+        visitRecord(nullptr, Param, RD, ParamTy, Handlers...);
+      }
+    } else if (ParamTy->isUnionType())
       KP_FOR_EACH(handleOtherType, Param, ParamTy);
     else if (ParamTy->isReferenceType())
       KP_FOR_EACH(handleOtherType, Param, ParamTy);
@@ -1957,8 +1960,29 @@ class SyclKernelFieldChecker : public SyclKernelFieldHandler {
   }
 
   bool handleStructType(ParmVarDecl *PD, QualType ParamTy) final {
-    Diag.Report(PD->getLocation(), diag::err_bad_kernel_param_type) << ParamTy;
-    IsInvalid = true;
+    CXXRecordDecl *RD = ParamTy->getAsCXXRecordDecl();
+    // For free functions all struct/class kernel arguments are forward declared
+    // in integration header, that adds additional restrictions for kernel
+    // arguments.
+    // Lambdas are not forward declarable. So, diagnose them properly.
+    if (RD->isLambda()) {
+      Diag.Report(PD->getLocation(), diag::err_bad_kernel_param_type)
+          << ParamTy;
+      IsInvalid = true;
+      return isValid();
+    }
+
+    // Check that the type is defined at namespace scope.
+    const DeclContext *DeclCtx = RD->getDeclContext();
+    while (!DeclCtx->isTranslationUnit() &&
+           (isa<NamespaceDecl>(DeclCtx) || isa<LinkageSpecDecl>(DeclCtx)))
+      DeclCtx = DeclCtx->getParent();
+
+    if (!DeclCtx->isTranslationUnit()) {
+      Diag.Report(PD->getLocation(), diag::err_bad_kernel_param_type)
+          << ParamTy;
+      IsInvalid = true;
+    }
     return isValid();
   }
 
@@ -2037,14 +2061,16 @@ class SyclKernelFieldChecker : public SyclKernelFieldHandler {
   }
 
   bool enterStruct(const CXXRecordDecl *, ParmVarDecl *, QualType) final {
-    // TODO
-    unsupportedFreeFunctionParamType();
+    // TODO manipulate struct depth once special types are supported for free
+    // function kernels.
+    // ++StructFieldDepth;
     return true;
   }
 
   bool leaveStruct(const CXXRecordDecl *, ParmVarDecl *, QualType) final {
-    // TODO
-    unsupportedFreeFunctionParamType();
+    // TODO manipulate struct depth once special types are supported for free
+    // function kernels.
+    // --StructFieldDepth;
     return true;
   }
 
@@ -2162,8 +2188,7 @@ class SyclKernelDecompMarker : public SyclKernelFieldHandler {
   }
 
   bool handlePointerType(ParmVarDecl *, QualType) final {
-    // TODO
-    unsupportedFreeFunctionParamType();
+    PointerStack.back() = targetRequiresNewType(SemaSYCLRef.getASTContext());
     return true;
   }
 
@@ -2194,8 +2219,10 @@ class SyclKernelDecompMarker : public SyclKernelFieldHandler {
   }
 
   bool enterStruct(const CXXRecordDecl *, ParmVarDecl *, QualType) final {
-    // TODO
-    unsupportedFreeFunctionParamType();
+    // TODO handle decomposition once special type arguments are supported
+    // for free function kernels.
+    // CollectionStack.push_back(false);
+    PointerStack.push_back(false);
     return true;
   }
 
@@ -2221,10 +2248,24 @@ class SyclKernelDecompMarker : public SyclKernelFieldHandler {
     return true;
   }
 
-  bool leaveStruct(const CXXRecordDecl *RD, ParmVarDecl *PD,
+  bool leaveStruct(const CXXRecordDecl *, ParmVarDecl *,
                    QualType ParamTy) final {
-    // TODO
-    unsupportedFreeFunctionParamType();
+    CXXRecordDecl *RD = ParamTy->getAsCXXRecordDecl();
+    assert(RD && "should not be null.");
+    // TODO handle decomposition once special type arguments are supported
+    // for free function kernels.
+    // if (CollectionStack.pop_back_val()) {
+    //   if (!RD->hasAttr<SYCLRequiresDecompositionAttr>())
+    //     RD->addAttr(SYCLRequiresDecompositionAttr::CreateImplicit(
+    //         SemaSYCLRef.getASTContext()));
+    //   CollectionStack.back() = true;
+    //   PointerStack.pop_back();
+    if (PointerStack.pop_back_val()) {
+      PointerStack.back() = true;
+      if (!RD->hasAttr<SYCLGenerateNewTypeAttr>())
+        RD->addAttr(SYCLGenerateNewTypeAttr::CreateImplicit(
+            SemaSYCLRef.getASTContext()));
+    }
     return true;
   }
 
@@ -2974,8 +3015,15 @@ class SyclKernelDeclCreator : public SyclKernelFieldHandler {
 
   bool handleNonDecompStruct(const CXXRecordDecl *RD, ParmVarDecl *PD,
                              QualType ParamTy) final {
-    // TODO
-    unsupportedFreeFunctionParamType();
+    // This is a struct parameter which should not be decomposed.
+    CXXRecordDecl *ParamRecordDecl = ParamTy->getAsCXXRecordDecl();
+    assert(ParamRecordDecl && "Type must be a C++ record type");
+    // Check if we need to generate a new type for this record,
+    // i.e. this record contains pointers.
+    if (ParamRecordDecl->hasAttr<SYCLGenerateNewTypeAttr>())
+      addParam(PD, GenerateNewRecordType(ParamRecordDecl));
+    else
+      addParam(PD, ParamTy);
     return true;
   }
 
@@ -3203,8 +3251,7 @@ class SyclKernelArgsSizeChecker : public SyclKernelFieldHandler {
 
   bool handleNonDecompStruct(const CXXRecordDecl *, ParmVarDecl *,
                              QualType ParamTy) final {
-    // TODO
-    unsupportedFreeFunctionParamType();
+    addParam(ParamTy);
     return true;
   }
 
@@ -4194,7 +4241,7 @@ class FreeFunctionKernelBodyCreator : public SyclKernelFieldHandler {
 
   // Creates a DeclRefExpr to the ParmVar that represents the current pointer
   // parameter.
-  Expr *createPointerParamReferenceExpr(QualType PointerTy, bool Wrapped) {
+  Expr *createPointerParamReferenceExpr(QualType PointerTy) {
     ParmVarDecl *FreeFunctionParameter =
         DeclCreator.getParamVarDeclsForCurrentField()[0];
 
@@ -4212,6 +4259,50 @@ class FreeFunctionKernelBodyCreator : public SyclKernelFieldHandler {
     return DRE;
   }
 
+  Expr *createGetAddressOf(Expr *E) {
+    return UnaryOperator::Create(
+        SemaSYCLRef.getASTContext(), E, UO_AddrOf,
+        SemaSYCLRef.getASTContext().getPointerType(E->getType()), VK_PRValue,
+        OK_Ordinary, SourceLocation(), false,
+        SemaSYCLRef.SemaRef.CurFPFeatureOverrides());
+  }
+
+  Expr *createDerefOp(Expr *E) {
+    return UnaryOperator::Create(SemaSYCLRef.getASTContext(), E, UO_Deref,
+                                 E->getType()->getPointeeType(), VK_LValue,
+                                 OK_Ordinary, SourceLocation(), false,
+                                 SemaSYCLRef.SemaRef.CurFPFeatureOverrides());
+  }
+
+  Expr *createReinterpretCastExpr(Expr *E, QualType To) {
+    return CXXReinterpretCastExpr::Create(
+        SemaSYCLRef.getASTContext(), To, VK_PRValue, CK_BitCast, E,
+        /*Path=*/nullptr,
+        SemaSYCLRef.getASTContext().getTrivialTypeSourceInfo(To),
+        SourceLocation(), SourceLocation(), SourceRange());
+  }
+
+  Expr *createStructTemporary(ParmVarDecl *OrigFunctionParameter) {
+    Expr *DRE = createParamReferenceExpr();
+
+    assert(OrigFunctionParameter && "no parameter?");
+
+    CXXRecordDecl *RD = OrigFunctionParameter->getType()->getAsCXXRecordDecl();
+    InitializedEntity Entity = InitializedEntity::InitializeParameter(
+        SemaSYCLRef.getASTContext(), OrigFunctionParameter);
+
+    if (RD->hasAttr<SYCLGenerateNewTypeAttr>()) {
+      DRE = createReinterpretCastExpr(
+          createGetAddressOf(DRE), SemaSYCLRef.getASTContext().getPointerType(
+                                       OrigFunctionParameter->getType()));
+      DRE = createDerefOp(DRE);
+    }
+
+    ExprResult ArgE = SemaSYCLRef.SemaRef.PerformCopyInitialization(
+        Entity, SourceLocation(), DRE, false, false);
+    return ArgE.getAs<Expr>();
+  }
+
   // For a free function such as:
   // void f(int i, int* p, struct Simple S) { ... }
   //
@@ -4281,7 +4372,7 @@ class FreeFunctionKernelBodyCreator : public SyclKernelFieldHandler {
   }
 
   bool handlePointerType(ParmVarDecl *PD, QualType ParamTy) final {
-    Expr *PointerRef = createPointerParamReferenceExpr(ParamTy, false);
+    Expr *PointerRef = createPointerParamReferenceExpr(ParamTy);
     ArgExprs.push_back(PointerRef);
     return true;
   }
@@ -4299,10 +4390,10 @@ class FreeFunctionKernelBodyCreator : public SyclKernelFieldHandler {
     return true;
   }
 
-  bool handleNonDecompStruct(const CXXRecordDecl *, ParmVarDecl *,
+  bool handleNonDecompStruct(const CXXRecordDecl *, ParmVarDecl *PD,
                              QualType) final {
-    // TODO
-    unsupportedFreeFunctionParamType();
+    Expr *TempCopy = createStructTemporary(PD);
+    ArgExprs.push_back(TempCopy);
     return true;
   }
 
@@ -4588,8 +4679,7 @@ class SyclKernelIntHeaderCreator : public SyclKernelFieldHandler {
 
   bool handleNonDecompStruct(const CXXRecordDecl *, ParmVarDecl *PD,
                              QualType ParamTy) final {
-    // TODO
-    unsupportedFreeFunctionParamType();
+    addParam(PD, ParamTy, SYCLIntegrationHeader::kind_std_layout);
     return true;
   }
 
@@ -5435,6 +5525,7 @@ void SemaSYCL::MarkDevices() {
 
 void SemaSYCL::ProcessFreeFunction(FunctionDecl *FD) {
   if (isFreeFunction(*this, FD)) {
+    SyclKernelDecompMarker DecompMarker(*this);
     SyclKernelFieldChecker FieldChecker(*this);
     SyclKernelUnionChecker UnionChecker(*this);
 
@@ -5443,7 +5534,8 @@ void SemaSYCL::ProcessFreeFunction(FunctionDecl *FD) {
     DiagnosingSYCLKernel = true;
 
     // Check parameters of free function.
-    Visitor.VisitFunctionParameters(FD, FieldChecker, UnionChecker);
+    Visitor.VisitFunctionParameters(FD, FieldChecker, UnionChecker,
+                                    DecompMarker);
 
     DiagnosingSYCLKernel = false;
 
@@ -5889,6 +5981,14 @@ class SYCLFwdDeclEmitter
   void VisitPackTemplateArgument(const TemplateArgument &TA) {
     VisitTemplateArgs(TA.getPackAsArray());
   }
+
+  void VisitFunctionProtoType(const FunctionProtoType *T) {
+    for (const auto Ty : T->getParamTypes())
+      Visit(Ty.getCanonicalType());
+    // So far this visitor method is only used for free function kernels whose
+    // return type is void anyway, so it is not visited. Otherwise, add if
+    // required.
+  }
 };
 
 class SYCLKernelNameTypePrinter
@@ -6325,10 +6425,15 @@ void SYCLIntegrationHeader::emit(raw_ostream &O) {
   for (const KernelDesc &K : KernelDescs) {
     if (!isFreeFunction(S, K.SyclKernel))
       continue;
-
     ++FreeFunctionCount;
     // Generate forward declaration for free function.
     O << "\n// Definition of " << K.Name << " as a free function kernel\n";
+
+    O << "\n";
+    O << "// Forward declarations of kernel and its argument types:\n";
+    FwdDeclEmitter.Visit(K.SyclKernel->getType());
+    O << "\n";
+
     if (K.SyclKernel->getLanguageLinkage() == CLanguageLinkage)
       O << "extern \"C\" ";
     std::string ParmList;