[SYCL] add support for -fsycl-link

Generate a wrapped device binary that can be used independently with a host
link step.  Takes the provided fat objects or source, extracts or creates the
associated device binaries and wraps them to be used during a regular host
link step

Signed-off-by: Michael D Toguchi <[email protected]>

Author: mdtoguchi

clang/include/clang/Basic/DiagnosticDriverKinds.td

@@ -235,6 +235,7 @@ def err_drv_invalid_omp_target : Error<"OpenMP target is invalid: '%0'">;
 def err_drv_invalid_sycl_target : Error<"SYCL target is invalid: '%0'">;
 def err_drv_sycl_target_conflict : Error<"The option -fsycl-targets conflicts with -fsycl-link-targets">;
 def err_drv_sycl_add_link_conflict : Error<"The option -fsycl-link-targets conflicts with -fsycl-add-targets">;
+def err_drv_sycl_link_link_targets_conflict : Error<"The option -fsycl-link-targets conflicts with -fsycl-link">;
 def err_drv_omp_host_ir_file_not_found : Error<
   "The provided host compiler IR file '%0' is required to generate code for OpenMP target regions but cannot be found.">;
 def err_drv_omp_host_target_not_supported : Error<

clang/include/clang/Driver/Options.td

@@ -1719,6 +1719,8 @@ def fsycl_use_bitcode : Flag<["-"], "fsycl-use-bitcode">,
   Flags<[CC1Option]>, HelpText<"Use LLVM bitcode instead of SPIR-V in fat objects">;
 def fno_sycl_use_bitcode : Flag<["-"], "fno-sycl-use-bitcode">,
   Flags<[CC1Option]>, HelpText<"Use SPIR-V instead of LLVM bitcode in fat objects">;
+def fsycl_link : Flag<["-"], "fsycl-link">,
+  Flags<[CC1Option]>, HelpText<"Generate partially linked device object to be used with the host link">;
 def fsyntax_only : Flag<["-"], "fsyntax-only">,
   Flags<[DriverOption,CoreOption,CC1Option]>, Group<Action_Group>;
 def ftabstop_EQ : Joined<["-"], "ftabstop=">, Group<f_Group>;

clang/lib/Driver/Driver.cpp

@@ -719,12 +719,17 @@ void Driver::CreateOffloadingDeviceToolChains(Compilation &C,
           C.getInputArgs().getLastArg(options::OPT_fsycl_link_targets_EQ);
   Arg *SYCLAddTargets =
           C.getInputArgs().getLastArg(options::OPT_fsycl_add_targets_EQ);
+  Arg *SYCLLink =
+          C.getInputArgs().getLastArg(options::OPT_fsycl_link);
   // -fsycl-targets cannot be used with -fsycl-link-targets
   if (SYCLTargets && SYCLLinkTargets)
     Diag(clang::diag::err_drv_sycl_target_conflict);
   // -fsycl-link-targets and -fsycl-add-targets cannot be used together
   if (SYCLLinkTargets && SYCLAddTargets)
     Diag(clang::diag::err_drv_sycl_add_link_conflict);
+  // -fsycl-link-targets is not allowed with -fsycl-link
+  if (SYCLLinkTargets && SYCLLink)
+    Diag(clang::diag::err_drv_sycl_link_link_targets_conflict);
 
   // -fsycl-add-targets is a list of paired items (Triple and file) which are
   // gathered and used to be linked into the final device binary. This can
@@ -2997,6 +3002,9 @@ class OffloadingActionBuilder final {
     /// Flag to signal if the user requested device-only compilation.
     bool CompileDeviceOnly = false;
 
+    /// Flag to signal if the user requested the device object to be wrapped
+    bool WrapDeviceOnlyBinary = false;
+
     /// The SYCL actions for the current input.
     ActionList SYCLDeviceActions;
 
@@ -3061,8 +3069,17 @@ class OffloadingActionBuilder final {
           for (auto SDA : SYCLDeviceActions) {
             SYCLLinkBinaryList.push_back(SDA);
           }
-          SYCLLinkBinary = C.MakeAction<LinkJobAction>(SYCLLinkBinaryList,
-                                                       types::TY_Image);
+          if (WrapDeviceOnlyBinary) {
+            auto *DeviceLinkAction =
+              C.MakeAction<LinkJobAction>(SYCLLinkBinaryList, types::TY_Image);
+            // Wrap the binary when -fsycl-link is given
+            SYCLLinkBinary =
+                C.MakeAction<OffloadWrappingJobAction>(DeviceLinkAction,
+                                                       types::TY_Object);
+          }
+          else
+            SYCLLinkBinary = C.MakeAction<LinkJobAction>(SYCLLinkBinaryList,
+                                                         types::TY_Image);
 
           // Remove the SYCL actions as they are already connected to an host
           // action or fat binary.
@@ -3217,9 +3234,11 @@ class OffloadingActionBuilder final {
 
       Arg *SYCLLinkTargets = Args.getLastArg(
                                   options::OPT_fsycl_link_targets_EQ);
-      CompileDeviceOnly = SYCLLinkTargets &&
-                          SYCLLinkTargets->getOption().matches(
-                              options::OPT_fsycl_link_targets_EQ);
+      WrapDeviceOnlyBinary = Args.hasArg(options::OPT_fsycl_link);
+      CompileDeviceOnly = (SYCLLinkTargets &&
+                           SYCLLinkTargets->getOption().matches(
+                              options::OPT_fsycl_link_targets_EQ)) ||
+                          WrapDeviceOnlyBinary;
       Arg *SYCLAddTargets = Args.getLastArg(
                                   options::OPT_fsycl_add_targets_EQ);
       if (SYCLAddTargets) {
@@ -4654,9 +4673,10 @@ InputInfo Driver::BuildJobsForActionNoCache(
     Result = InputInfo(A, BaseInput);
   else {
     std::string OffloadingPrefix;
-    // When generating binaries with -fsycl-link-target, the output file prefix
-    // is the triple arch only
-    if (Args.getLastArg(options::OPT_fsycl_link_targets_EQ)) {
+    // When generating binaries with -fsycl-link-target or -fsycl-link, the
+    // output file prefix is the triple arch only.
+    if (Args.getLastArg(options::OPT_fsycl_link_targets_EQ) ||
+        Args.hasArg(options::OPT_fsycl_link)) {
       OffloadingPrefix = "-";
       OffloadingPrefix += TC->getTriple().getArchName();
     } else {

clang/test/Driver/sycl-offload.c

@@ -282,6 +282,32 @@
 
 /// ###########################################################################
 
+/// Check -fsycl-link behaviors unbundle
+// RUN:   touch %t.o
+// RUN:   %clang -### -ccc-print-phases -target x86_64-unknown-linux-gnu -fsycl -o %t.out -fsycl-link %t.o 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHK-LINK-UB %s
+// CHK-LINK-UB: 0: input, "[[INPUT:.+\.o]]", object
+// CHK-LINK-UB: 1: clang-offload-unbundler, {0}, object
+// CHK-LINK-UB: 2: linker, {1}, image, (device-sycl)
+// CHK-LINK-UB: 3: clang-offload-wrapper, {2}, object, (device-sycl)
+// CHK-LINK-UB: 4: offload, "device-sycl (spir64-unknown-linux-sycldevice)" {3}, object
+
+/// ###########################################################################
+
+/// Check -fsycl-link behaviors from source
+// RUN:   %clang -### -ccc-print-phases -target x86_64-unknown-linux-gnu -fsycl -o %t.out -fsycl-link %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHK-LINK %s
+// CHK-LINK: 0: input, "[[INPUT:.+\.c]]", c, (device-sycl)
+// CHK-LINK: 1: preprocessor, {0}, cpp-output, (device-sycl)
+// CHK-LINK: 2: compiler, {1}, ir, (device-sycl)
+// CHK-LINK: 3: backend, {2}, assembler, (device-sycl)
+// CHK-LINK: 4: assembler, {3}, object, (device-sycl)
+// CHK-LINK: 5: linker, {4}, image, (device-sycl)
+// CHK-LINK: 6: clang-offload-wrapper, {5}, object, (device-sycl)
+// CHK-LINK: 7: offload, "device-sycl (spir64-unknown-linux-sycldevice)" {6}, object
+
+/// ###########################################################################
+
 /// Check -fsycl-add-targets=<triple> behaviors unbundle
 // RUN:   touch %t.o
 // RUN:   %clang -### -ccc-print-phases -target x86_64-unknown-linux-gnu -fsycl -o %t.out -fsycl-add-targets=spir64-unknown-linux-sycldevice:dummy.spv %t.o 2>&1 \