[Driver][SYCL] Fix processing when using -fsycl-link (#1765)

When using -fsycl-link, the expectation is for the generated object file
to be able to be linked in by a non-SYCL enabled compiler/linker.  The
generated object did not contain the proper device binary.  Fix this up
to go through all of the proper steps to create the wrapped .spv.

Signed-off-by: Michael D Toguchi <michael.d.toguchi@intel.com>

Author: mdtoguchi

clang/lib/Driver/Driver.cpp

@@ -3549,12 +3549,21 @@ class OffloadingActionBuilder final {
           for (auto SDA : SYCLDeviceActions)
             SYCLLinkBinaryList.push_back(SDA);
           if (WrapDeviceOnlyBinary) {
-            auto *DeviceLinkAction =
-              C.MakeAction<LinkJobAction>(SYCLLinkBinaryList, types::TY_Image);
-            // Wrap the binary when -fsycl-link is given
-            SYCLLinkBinary =
-                C.MakeAction<OffloadWrapperJobAction>(DeviceLinkAction,
-                                                      types::TY_Object);
+            // -fsycl-link behavior does the following to the unbundled device
+            // binaries:
+            //   1) Link them together using llvm-link
+            //   2) Pass the linked binary through sycl-post-link
+            //   3) Translate final .bc file to .spv
+            //   4) Wrap the binary with the offload wrapper which can be used
+            //      by any compilation link step.
+            auto *DeviceLinkAction = C.MakeAction<LinkJobAction>(
+                SYCLLinkBinaryList, types::TY_Image);
+            auto *PostLinkAction = C.MakeAction<SYCLPostLinkJobAction>(
+                DeviceLinkAction, types::TY_LLVM_BC);
+            auto *TranslateAction = C.MakeAction<SPIRVTranslatorJobAction>(
+                PostLinkAction, types::TY_Image);
+            SYCLLinkBinary = C.MakeAction<OffloadWrapperJobAction>(
+                TranslateAction, types::TY_Object);
           } else {
             auto *Link = C.MakeAction<LinkJobAction>(SYCLLinkBinaryList,
                                                          types::TY_Image);

clang/test/Driver/sycl-offload.c

@@ -423,8 +423,10 @@
 // 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-unknown-sycldevice{{.*}})" {3}, object
+// CHK-LINK-UB: 3: sycl-post-link, {2}, ir, (device-sycl)
+// CHK-LINK-UB: 4: llvm-spirv, {3}, image, (device-sycl)
+// CHK-LINK-UB: 5: clang-offload-wrapper, {4}, object, (device-sycl)
+// CHK-LINK-UB: 6: offload, "device-sycl (spir64-unknown-unknown-sycldevice)" {5}, object
 
 /// ###########################################################################
 
@@ -437,8 +439,10 @@
 // CHK-LINK: 1: preprocessor, {0}, cpp-output, (device-sycl)
 // CHK-LINK: 2: compiler, {1}, ir, (device-sycl)
 // CHK-LINK: 3: linker, {2}, image, (device-sycl)
-// CHK-LINK: 4: clang-offload-wrapper, {3}, object, (device-sycl)
-// CHK-LINK: 5: offload, "device-sycl (spir64-unknown-unknown-sycldevice{{.*}})" {4}, object
+// CHK-LINK: 4: sycl-post-link, {3}, ir, (device-sycl)
+// CHK-LINK: 5: llvm-spirv, {4}, image, (device-sycl)
+// CHK-LINK: 6: clang-offload-wrapper, {5}, object, (device-sycl)
+// CHK-LINK: 7: offload, "device-sycl (spir64-unknown-unknown-sycldevice)" {6}, object
 
 /// ###########################################################################