[llvm] [llvm][Support] Add support for executing a detached process (PR #81708)

[Michael Spencer via llvm-commits]

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@@ -284,6 +285,8 @@ static bool Execute(ProcessInfo &PI, StringRef Program,
   unsigned CreateFlags = CREATE_UNICODE_ENVIRONMENT;
   if (AffinityMask)
     CreateFlags |= CREATE_SUSPENDED;
+  if (DetachProcess)
+    CreateFlags |= DETACHED_PROCESS;
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Bigcheese wrote:

We discussed using `ShellExecute`, but it still gives you a console. The goal here is to not have a console at all. `DETACHED_PROCESS` gives the correct semantics for a daemon spawned by any given `clang` instance that doesn't belong to any specific instance.

https://github.com/llvm/llvm-project/pull/81708