[clang] [Clang][Driver] Parallelize device cc1 jobs for offload arches (PR #208254)

[Joseph Huber via cfe-commits]

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@@ -5132,6 +5132,56 @@ static void ProcessVSRuntimeLibrary(const ToolChain &TC, const ArgList &Args,
     CmdArgs.push_back("--dependent-lib=softintrin");
 }
 
+static bool CanRunOffloadDeviceCC1JobInParallel(const JobAction &JA,
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jhuber6 wrote:

General question, why do we need to touch `Clang.cpp` at all? I figured that we'd just be able to travel the tree of Jobs before executing and determine eligibility there.

https://github.com/llvm/llvm-project/pull/208254