[clang] [llvm] [Driver][SYCL] Add initial SYCL offload compilation support (PR #107493)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-darwin` running on `doug-worker-3` while building `clang,llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/23/builds/4847

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang :: Driver/sycl.c' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 1: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/clang -### -fsycl -c /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/sycl.c 2>&1 | /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/FileCheck /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/sycl.c --check-prefix=ENABLED
+ /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/clang -### -fsycl -c /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/sycl.c
+ /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/FileCheck /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/sycl.c --check-prefix=ENABLED
/Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/sycl.c:18:13: error: ENABLED: expected string not found in input
// ENABLED: "-cc1"{{.*}} "-fsycl-is-device"
            ^
<stdin>:1:1: note: scanning from here
clang version 20.0.0git (https://github.com/llvm/llvm-project.git 0b0d61101fa0648a09ebc1dc7a26ee9a89e91be8)
^
<stdin>:9:80: note: possible intended match here
0. Program arguments: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/clang -### -fsycl -c /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/sycl.c
                                                                               ^

Input file: <stdin>
Check file: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/sycl.c

-dump-input=help explains the following input dump.

Input was:
<<<<<<
            1: clang version 20.0.0git (https://github.com/llvm/llvm-project.git 0b0d61101fa0648a09ebc1dc7a26ee9a89e91be8) 
check:18'0     X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
            2: Target: x86_64-apple-darwin23.6.0 
check:18'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            3: Thread model: posix 
check:18'0     ~~~~~~~~~~~~~~~~~~~~
            4: InstalledDir: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin 
check:18'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            5: Build config: +assertions 
check:18'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~
            6: Assertion failed: (TargetInitialized && "Target not initialized!"), function isTargetWatchOSBased, file Darwin.h, line 458. 
check:18'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            7: PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script. 
check:18'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            8: Stack dump: 
check:18'0     ~~~~~~~~~~~~
            9: 0. Program arguments: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/clang -### -fsycl -c /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Driver/sycl.c 
check:18'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
check:18'1                                                                                    ?                                                                                                      possible intended match
           10: 1. Compilation construction 
check:18'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           11: 2. Building compilation jobs 
check:18'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           12: 3. Building compilation jobs 
check:18'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...

```

</details>

https://github.com/llvm/llvm-project/pull/107493