[NFC] Fix some warnings and errors under C++20

clang/lib/Driver/ToolChains/Cuda.h

@@ -203,7 +203,7 @@ class LLVM_LIBRARY_VISIBILITY CudaToolChain : public ToolChain {
 
   unsigned GetDefaultDwarfVersion() const override { return 2; }
 
-  Tool *SelectTool(const JobAction &JA) const;
+  Tool *SelectTool(const JobAction &JA) const override;
 
   const ToolChain &HostTC;
   CudaInstallationDetector CudaInstallation;

clang/lib/Sema/SemaSYCL.cpp

@@ -935,7 +935,7 @@ void KernelObjVisitor::VisitRecord(CXXRecordDecl *Owner, ParentTy &Parent,
 
 // A base type that the SYCL OpenCL Kernel construction task uses to implement
 // individual tasks.
-template <typename Derived> class SyclKernelFieldHandler {
+class SyclKernelFieldHandler {
 protected:
   Sema &SemaRef;
   SyclKernelFieldHandler(Sema &S) : SemaRef(S) {}
@@ -1001,11 +1001,12 @@ template <typename Derived> class SyclKernelFieldHandler {
   virtual bool enterArray() { return true; }
   virtual bool nextElement(QualType) { return true; }
   virtual bool leaveArray(FieldDecl *, QualType, int64_t) { return true; }
+
+  virtual ~SyclKernelFieldHandler() = default;
 };
 
 // A type to check the validity of all of the argument types.
-class SyclKernelFieldChecker
-    : public SyclKernelFieldHandler<SyclKernelFieldChecker> {
+class SyclKernelFieldChecker : public SyclKernelFieldHandler {
   bool IsInvalid = false;
   DiagnosticsEngine &Diag;
 
@@ -1101,8 +1102,7 @@ class SyclKernelFieldChecker
 };
 
 // A type to Create and own the FunctionDecl for the kernel.
-class SyclKernelDeclCreator
-    : public SyclKernelFieldHandler<SyclKernelDeclCreator> {
+class SyclKernelDeclCreator : public SyclKernelFieldHandler {
   FunctionDecl *KernelDecl;
   llvm::SmallVector<ParmVarDecl *, 8> Params;
   SyclKernelFieldChecker &ArgChecker;
@@ -1286,8 +1286,7 @@ class SyclKernelDeclCreator
   using SyclKernelFieldHandler::handleSyclSamplerType;
 };
 
-class SyclKernelBodyCreator
-    : public SyclKernelFieldHandler<SyclKernelBodyCreator> {
+class SyclKernelBodyCreator : public SyclKernelFieldHandler {
   SyclKernelDeclCreator &DeclCreator;
   llvm::SmallVector<Stmt *, 16> BodyStmts;
   llvm::SmallVector<Stmt *, 16> FinalizeStmts;
@@ -1696,12 +1695,8 @@ class SyclKernelBodyCreator
   using SyclKernelFieldHandler::leaveStruct;
 };
 
-class SyclKernelIntHeaderCreator
-    : public SyclKernelFieldHandler<SyclKernelIntHeaderCreator> {
+class SyclKernelIntHeaderCreator : public SyclKernelFieldHandler {
   SYCLIntegrationHeader &Header;
-  const CXXRecordDecl *KernelObj;
-  // Necessary to figure out the offset of the base class.
-  const CXXRecordDecl *CurStruct = nullptr;
   int64_t CurOffset = 0;
 
   void addParam(const FieldDecl *FD, QualType ArgTy,
@@ -1720,7 +1715,7 @@ class SyclKernelIntHeaderCreator
   SyclKernelIntHeaderCreator(Sema &S, SYCLIntegrationHeader &H,
                              const CXXRecordDecl *KernelObj, QualType NameType,
                              StringRef Name, StringRef StableName)
-      : SyclKernelFieldHandler(S), Header(H), KernelObj(KernelObj) {
+      : SyclKernelFieldHandler(S), Header(H) {
     Header.startKernel(Name, NameType, StableName, KernelObj->getLocation());
   }
 

llvm/include/llvm/Support/PropertySetIO.h

@@ -60,7 +60,7 @@ class PropertyValue {
   // Casts from int value to a type tag.
   static Expected<Type> getTypeTag(int T) {
     if (T < first || T > last)
-      return createStringError(std::error_code(), "bad property type " + T);
+      return createStringError(std::error_code(), "bad property type ", T);
     return static_cast<Type>(T);
   }
 

llvm/lib/Support/PropertySetIO.cpp

@@ -61,12 +61,12 @@ PropertySetRegistry::read(const MemoryBuffer *Buf) {
     case PropertyValue::Type::UINT32: {
       APInt ValV;
       if (Val.getAsInteger(10, ValV))
-        return createStringError(EC, "invalid property value: " + Val);
+        return createStringError(EC, "invalid property value: ", Val.data());
       Prop.set(static_cast<uint32_t>(ValV.getZExtValue()));
       break;
     }
     default:
-      return createStringError(EC, "unsupported property type: " + Ttag.get());
+      return createStringError(EC, "unsupported property type: ", Ttag.get());
     }
     (*CurPropSet)[Parts.first] = Prop;
   }
@@ -85,7 +85,8 @@ raw_ostream &operator<<(raw_ostream &Out, const PropertyValue &Prop) {
     Out << Prop.asUint32();
     break;
   default:
-    llvm_unreachable_internal("unsupported property type: " + Prop.getType());
+    llvm_unreachable(
+        ("unsupported property type: " + utostr(Prop.getType())).c_str());
   }
   return Out;
 }

sycl/include/CL/sycl/id.hpp

@@ -109,7 +109,9 @@ template <int dimensions = 1> class id : public detail::array<dimensions> {
 // OP is: ==, !=
 #ifndef __SYCL_DISABLE_ID_TO_INT_CONV__
   using detail::array<dimensions>::operator==;
+#if __cpp_impl_three_way_comparison < 201907
   using detail::array<dimensions>::operator!=;
+#endif
 
   /* Enable operators with integral types.
    * Template operators take precedence than type conversion. In the case of

sycl/source/detail/os_util.cpp

@@ -59,7 +59,7 @@ struct ModuleInfo {
 constexpr OSModuleHandle OSUtil::ExeModuleHandle;
 constexpr OSModuleHandle OSUtil::DummyModuleHandle;
 
-static int callback(struct dl_phdr_info *Info, size_t Size, void *Data) {
+static int callback(struct dl_phdr_info *Info, size_t, void *Data) {
   auto Base = reinterpret_cast<unsigned char *>(Info->dlpi_addr);
   auto MI = reinterpret_cast<ModuleInfo *>(Data);
   auto TestAddr = reinterpret_cast<const unsigned char *>(MI->VirtAddr);