[SYCL][Driver] Add clang driver option to enable SYCL compilation mode

Summary:
As a first step this implementation enables compilation of the offload
code.

Reviewers: ABataev

Subscribers: ebevhan, Anastasia, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D74048

Author: bader

clang/include/clang/Driver/Options.td

@@ -124,6 +124,9 @@ def pedantic_Group : OptionGroup<"<pedantic group>">, Group<f_Group>,
 def opencl_Group : OptionGroup<"<opencl group>">, Group<f_Group>,
                    DocName<"OpenCL flags">;
 
+def sycl_Group : OptionGroup<"<SYCL group>">, Group<f_Group>,
+                 DocName<"SYCL flags">;
+
 def m_Group : OptionGroup<"<m group>">, Group<CompileOnly_Group>,
               DocName<"Target-dependent compilation options">;
 
@@ -3407,6 +3410,11 @@ defm stack_arrays : BooleanFFlag<"stack-arrays">, Group<gfortran_Group>;
 defm underscoring : BooleanFFlag<"underscoring">, Group<gfortran_Group>;
 defm whole_file : BooleanFFlag<"whole-file">, Group<gfortran_Group>;
 
+// C++ SYCL options
+def fsycl : Flag<["-"], "fsycl">, Group<sycl_Group>,
+  HelpText<"Enable SYCL kernels compilation for device">;
+def fno_sycl : Flag<["-"], "fno-sycl">, Group<sycl_Group>,
+  HelpText<"Disable SYCL kernels compilation for device">;
 
 include "CC1Options.td"
 

clang/lib/Driver/ToolChains/Clang.cpp

@@ -4023,6 +4023,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back(Args.MakeArgString(NormalizedTriple));
   }
 
+  if (Args.hasFlag(options::OPT_fsycl, options::OPT_fno_sycl, false))
+    CmdArgs.push_back("-fsycl-is-device");
+
   if (IsOpenMPDevice) {
     // We have to pass the triple of the host if compiling for an OpenMP device.
     std::string NormalizedTriple =

clang/test/Driver/sycl.c

@@ -0,0 +1,10 @@
+// RUN: %clang -### -fsycl -c %s 2>&1 | FileCheck %s --check-prefix=ENABLED
+// RUN: %clang -### -fsycl %s 2>&1 | FileCheck %s --check-prefix=ENABLED
+// RUN: %clang -### -fno-sycl -fsycl %s 2>&1 | FileCheck %s --check-prefix=ENABLED
+// RUN: %clangxx -### -fsycl %s 2>&1 | FileCheck %s --check-prefix=ENABLED
+// RUN: %clangxx -### -fno-sycl %s 2>&1 | FileCheck %s --check-prefix=DISABLED
+// RUN: %clangxx -### -fsycl -fno-sycl %s 2>&1 | FileCheck %s --check-prefix=DISABLED
+// RUN: %clangxx -### %s 2>&1 | FileCheck %s --check-prefix=DISABLED
+
+// ENABLED: "-cc1"{{.*}} "-fsycl-is-device"
+// DISABLED-NOT: "-fsycl-is-device"