[SYCL] Conditionally enable diagnosing that requires integration header (#5044)

#4945 introduced a new diagnostic that
works correctly only if integration header is included. However it is
possible that `-fsycl-is-host` flag can be used without integration
header, so the diagnostic should be issued only if integration header is
included. This patch adds new cc1 option that helps to understand that.

Author: Fznamznon

clang/include/clang/Basic/LangOptions.def

@@ -273,6 +273,8 @@ LANGOPT(
     "get/operator[], get_id/operator[] and get_global_id/get_global_linear_id "
     "in SYCL class id, iterm and nd_iterm")
 LANGOPT(SYCLDisableRangeRounding, 1, 0, "Disable parallel for range rounding")
+LANGOPT(SYCLEnableIntHeaderDiags, 1, 0, "Enable diagnostics that require the "
+        "SYCL integration header")
 
 LANGOPT(HIPUseNewLaunchAPI, 1, 0, "Use new kernel launching API for HIP")
 

clang/include/clang/Driver/Options.td

@@ -6060,6 +6060,9 @@ def fenable_sycl_dae : Flag<["-"], "fenable-sycl-dae">,
 def fsycl_disable_range_rounding : Flag<["-"], "fsycl-disable-range-rounding">,
   HelpText<"Disable parallel for range rounding.">,
   MarshallingInfoFlag<LangOpts<"SYCLDisableRangeRounding">>;
+def fsycl_enable_int_header_diags: Flag<["-"], "fsycl-enable-int-header-diags">,
+  HelpText<"Enable diagnostics that require the SYCL integration header.">,
+  MarshallingInfoFlag<LangOpts<"SYCLEnableIntHeaderDiags">>;
 
 } // let Flags = [CC1Option, NoDriverOption]
 

clang/lib/Driver/ToolChains/Clang.cpp

@@ -4853,6 +4853,10 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
         // header file.
         CmdArgs.push_back("-dependency-filter");
         CmdArgs.push_back(Args.MakeArgString(Header));
+
+        // Since this is a host compilation and the integration header is
+        // included, enable the integration header based diagnostics.
+        CmdArgs.push_back("-fsycl-enable-int-header-diags");
       }
       // Let the FE know we are doing a SYCL offload compilation, but we are
       // doing the host pass.

clang/lib/Frontend/CompilerInvocation.cpp

@@ -491,6 +491,13 @@ static bool FixupInvocation(CompilerInvocation &Invocation,
     Diags.Report(diag::err_drv_argument_not_allowed_with) << "-fsycl-is-device"
                                                           << "-fsycl-is-host";
 
+  // SYCLEnableIntHeader implies SYCLIsHost. Error if
+  // -fsycl-enable-int-header-diags is passed without -fsycl-is-host.
+  if (LangOpts.SYCLEnableIntHeaderDiags && !LangOpts.SYCLIsHost)
+    Diags.Report(diag::err_opt_not_valid_without_opt)
+        << "-fsycl-enable-int-header-diags"
+        << "-fsycl-is-host";
+
   if (Args.hasArg(OPT_fgnu89_inline) && LangOpts.CPlusPlus)
     Diags.Report(diag::err_drv_argument_not_allowed_with)
         << "-fgnu89-inline" << GetInputKindName(IK);

clang/lib/Sema/SemaSYCL.cpp

@@ -3515,7 +3515,8 @@ class SYCLKernelNameTypeVisitor
           // case will resolve to ::main::KernelName1 (instead of
           // ::KernelName1). Since this is not visible to runtime code that
           // submits kernels, this is invalid.
-          if (Tag->isCompleteDefinition() || S.getLangOpts().SYCLIsHost) {
+          if (Tag->isCompleteDefinition() ||
+              S.getLangOpts().SYCLEnableIntHeaderDiags) {
             S.Diag(KernelInvocationFuncLoc,
                    diag::err_sycl_kernel_incorrectly_named)
                 << /* kernel name should be forward declarable at namespace

clang/test/CodeGenSYCL/loop_fusion_host.cpp

@@ -5,14 +5,6 @@ __attribute__((sycl_kernel)) void kernel(const Func &kernelFunc) {
   kernelFunc();
 }
 
-// This test uses SYCL host only mode without integration header, so
-// forward declare used kernel name class, otherwise it will be diagnosed by
-// the diagnostic implemented in https://github.com/intel/llvm/pull/4945.
-// The error happens because in host mode it is assumed that all kernel names
-// are forward declared at global or namespace scope because of integration
-// header.
-class kernel_name_1;
-
 template <int SIZE>
 class KernelFunctor5 {
 public:

clang/test/CodeGenSYCL/stall_enable_host.cpp

@@ -2,14 +2,6 @@
 
 // Tests for IR of Intel FPGA [[intel::use_stall_enable_clusters]] function attribute on Host (no-op in IR-CodeGen for host-mode).
 
-// This test uses SYCL host only mode without integration header, so
-// forward declare used kernel name class, otherwise it will be diagnosed by
-// the diagnostic implemented in https://github.com/intel/llvm/pull/4945.
-// The error happens because in host mode it is assumed that all kernel names
-// are forward declared at global or namespace scope because of integration
-// header.
-class kernel_name_1;
-
 [[intel::use_stall_enable_clusters]] void test() {}
 
 void test1() {

clang/test/Frontend/sycl-int-header-diags.cpp

@@ -0,0 +1,6 @@
+// Test that we disallow -fsycl-enable-int-header-diags without -fsycl-is-host.
+
+// RUN: not %clang_cc1 -fsycl-enable-int-header-diags %s 2>&1 | FileCheck --check-prefix=ERROR %s
+// RUN: not %clang_cc1 -fsycl-is-device -fsycl-enable-int-header-diags %s 2>&1 | FileCheck --check-prefix=ERROR %s
+
+// ERROR: error: option '-fsycl-enable-int-header-diags' cannot be specified without '-fsycl-is-host'

clang/test/SemaSYCL/non-fwd-declarable-kernel-name.cpp

@@ -1,7 +1,13 @@
 // RUN: %clang_cc1 -fsycl-is-device -internal-isystem %S/Inputs -fno-sycl-unnamed-lambda -fsyntax-only -sycl-std=2020 -fsycl-int-header=%t.h %s
-// RUN: %clang_cc1 -fsycl-is-host -internal-isystem %S/Inputs -fno-sycl-unnamed-lambda -fsyntax-only -verify -include %t.h %s
+// RUN: %clang_cc1 -fsycl-is-host -DHEADER_FLAG -fsycl-enable-int-header-diags -internal-isystem %S/Inputs -fno-sycl-unnamed-lambda -fsyntax-only -verify -include %t.h %s
+// RUN: %clang_cc1 -fsycl-is-host -DNO_HEADER_FLAG -internal-isystem %S/Inputs -fno-sycl-unnamed-lambda -fsyntax-only -verify -include %t.h %s
 
-// This test verifies that incorrect kernel names are diagnosed correctly.
+// This test verifies that incorrect kernel names are diagnosed correctly if
+// integration header is included.
+
+#ifdef NO_HEADER_FLAG
+// expected-no-diagnostics
+#endif // NO_HEADER_FLAG
 
 #include "sycl.hpp"
 
@@ -29,18 +35,24 @@ int main() {
   });
 
   class NotOk;
+#ifdef HEADER_FLAG
   // expected-error@#KernelSingleTask {{'NotOk' is invalid; kernel name should be forward declarable at namespace scope}}
-  // expected-note@+2 {{in instantiation of function template specialization}}
+  // expected-note@+3 {{in instantiation of function template specialization}}
+#endif // HEADER_FLAG
   q.submit([&](handler &h) {
     h.single_task<class NotOk>([]() { function(); });
   });
+#ifdef HEADER_FLAG
   // expected-error@#KernelSingleTask {{'myWrapper::insideStruct' is invalid; kernel name should be forward declarable at namespace scope}}
-  // expected-note@+2 {{in instantiation of function template specialization}}
+  // expected-note@+3 {{in instantiation of function template specialization}}
+#endif // HEADER_FLAG
   q.submit([&](handler &h) {
     h.single_task<class myWrapper::insideStruct>([]() { function(); });
   });
+#ifdef HEADER_FLAG
   // expected-error@#KernelSingleTask {{'RandomTemplate<NotOk>' is invalid; kernel name should be forward declarable at namespace scope}}
-  // expected-note@+2 {{in instantiation of function template specialization}}
+  // expected-note@+3 {{in instantiation of function template specialization}}
+#endif // HEADER_FLAG
   q.submit([&](handler &h) {
     h.single_task<RandomTemplate<NotOk>>([]() { function(); });
   });

sycl/test/warnings/sycl_2020_deprecations.cpp

@@ -6,14 +6,6 @@
 #include <CL/sycl.hpp>
 #include <sycl/ext/intel/online_compiler.hpp>
 
-// This test uses SYCL host only mode without integration header, so
-// forward declare used kernel name class, otherwise it will be diagnosed by
-// the diagnostic implemented in https://github.com/intel/llvm/pull/4945.
-// The error happens because in host mode it is assumed that all kernel names
-// are forward declared at global or namespace scope because of integration
-// header.
-class Test;
-
 int main() {
   cl_context ClCtx;
   // expected-error@+1 {{no matching constructor for initialization of 'sycl::context'}}