[clang] [Clang] add option --offload-jobs=N (PR #135229)

[Joseph Huber via cfe-commits]

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@@ -1233,6 +1233,10 @@ def offload_compression_level_EQ : Joined<["--"], "offload-compression-level=">,
   Flags<[HelpHidden]>,
   HelpText<"Compression level for offload device binaries (HIP only)">;
 
+def offload_jobs_EQ : Joined<["--"], "offload-jobs=">,
+  HelpText<"Set the number of threads for the clang-linker-wrapper. Defaults to"
+           " half of the available hardware threads if not specified.">;
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jhuber6 wrote:

Hm, we could possibly prevent the linker wrapper from creating more threads if there aren't multiple images at least. But yeah, I think that defaulting to a lot of parallelism can be problematic.

https://github.com/llvm/llvm-project/pull/135229