Add parsing of OpenCL C++ -cl-std flags (#510)

Hello!

Support for OpenCL C++ was added into LLVM 14, but IGC doesn't support
parsing of those flags just yet. I've opened PRs which adds support for
parsing these flags to the following repositories:
[intel-graphics-compiler](intel/intel-graphics-compiler#328),
[compute-runtime](intel/compute-runtime#731) and
[opencl-clang](#510).

The options are passed down into LLVM which then happily compiles my C++
kernel.

PRs should be merged in the following order: opencl-clang,
intel-graphics-compiler, then finally compute-runtime.

Kind regards,
-Lucas

Co-authored-by: Lucas Zadrozny <lucas.zadrozny@hotmail.com>

Author: lucasz93

opencl_clang_options.td

@@ -34,6 +34,9 @@ def cl_std_CL1_1: Flag<["-"], "cl-std=CL1.1">;
 def cl_std_CL1_2: Flag<["-"], "cl-std=CL1.2">;
 def cl_std_CL2_0: Flag<["-"], "cl-std=CL2.0">;
 def cl_std_CL3_0: Flag<["-"], "cl-std=CL3.0">;
+def cl_std_CLCxx: Flag<["-"], "cl-std=CLC++">;
+def cl_std_CLCxx1_0: Flag<["-"], "cl-std=CLC++1.0">;
+def cl_std_CLCxx2021: Flag<["-"], "cl-std=CLC++2021">;
 def cl_uniform_work_group_size: Flag<["-"], "cl-uniform-work-group-size">;
 def cl_no_subgroup_ifp: Flag<["-"], "cl-no-subgroup-ifp">;
 def triple : Separate<["-"], "triple">,  HelpText<"Specify target triple (e.g. i686-apple-darwin9)">;

options_compile.cpp

@@ -81,6 +81,7 @@ std::string EffectiveOptionsFilter::processOptions(const OpenCLArgList &args,
                                                    ArgsVector &effectiveArgs) {
   // Reset args
   int iCLStdSet = 0;
+  bool isCpp = false;
   bool fp64Enabled = false;
   std::string szTriple;
   std::string sourceName(llvm::Twine(s_progID++).str());
@@ -150,6 +151,17 @@ std::string EffectiveOptionsFilter::processOptions(const OpenCLArgList &args,
       iCLStdSet = 300;
       effectiveArgs.push_back((*it)->getAsString(args));
       break;
+    case OPT_COMPILE_cl_std_CLCxx:
+    case OPT_COMPILE_cl_std_CLCxx1_0:
+      iCLStdSet = 200;
+      isCpp = true;
+      effectiveArgs.push_back((*it)->getAsString(args));
+      break;
+    case OPT_COMPILE_cl_std_CLCxx2021:
+      iCLStdSet = 300;
+      isCpp = true;
+      effectiveArgs.push_back((*it)->getAsString(args));
+      break;
     case OPT_COMPILE_triple:
       szTriple = (*it)->getValue();
       break;
@@ -231,7 +243,9 @@ std::string EffectiveOptionsFilter::processOptions(const OpenCLArgList &args,
 
   // Specifying the option makes clang emit function body for functions
   // marked with inline keyword.
-  effectiveArgs.push_back("-fgnu89-inline");
+  if (!isCpp) {
+    effectiveArgs.push_back("-fgnu89-inline");
+  }
 
   // Do not support all extensions by default. Support for a particular
   // extension should be enabled by passing a '-cl-ext' option in pszOptionsEx.