Add additional comment describing individual wrapping step.

Author: mdtoguchi

clang/lib/Driver/Driver.cpp

@@ -5432,6 +5432,52 @@ class OffloadingActionBuilder final {
                   BundlingActions, types::TY_Object);
               if (auto *OWA = dyn_cast<OffloadWrapperJobAction>(DeviceAction))
                 OWA->setOffloadKind(Action::OFK_Host);
+              // The Backend compilation step performed here is being done for
+              // creating FPGA archives.  The possible split binaries after
+              // sycl-post-link need to be individually wrapped as opposed to
+              // being passed into the clang-offload-wrapper via a table and
+              // using the -batch option - effectively creating a single
+              // binary.  The resulting archive created from -fsycl-link should
+              // not contain the singular binary, but should be individual
+              // binaries to be consumed later by either the -fsycl-link=image
+              // device compilation step or being linked into the final exe.
+              //
+              // Typical compile flow:
+              //               .bc
+              //                |
+              //     sycl-post-link -split=kernel
+              //                |
+              //       +--------+--------+
+              //       |        |        |
+              //     split1   split2   split3
+              //       |        |        |
+              // llvm-spirv llvm-spirv llvm-spirv
+              //       |        |        |
+              //     ocloc    ocloc    ocloc
+              //       |        |        |
+              //       +--------+--------+
+              //                |
+              //     clang-offload-wrapper -batch
+              //                |
+              //               .o
+              //
+              // Individual wrap compile flow:
+              //               .bc
+              //                |
+              //     sycl-post-link -split=kernel
+              //                |
+              //       +--------+--------+
+              //       |        |        |
+              //     split1   split2   split3
+              //       |        |        |
+              // llvm-spirv llvm-spirv llvm-spirv
+              //       |        |        |
+              //     ocloc    ocloc    ocloc
+              //       |        |        |
+              //     wrap     wrap     wrap
+              //       |        |        |
+              //      .o       .o       .o
+              //
               Action *CompiledDeviceAction =
                   C.MakeAction<OffloadWrapperJobAction>(FPGAAOTAction,
                                                         types::TY_Tempfilelist);