[llvm] [dsymutil] Filter our swiftinterface files from the toolchain. (PR #71205)

[Jonas Devlieghere via llvm-commits]

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@@ -167,6 +167,21 @@ void CompileUnit::cleanupDataAfterClonning() {
   getOrigUnit().clear();
 }
 
+/// Make a best effort to guess the
+/// Xcode.app/Contents/Developer/Toolchains/ path from an SDK path.
+static SmallString<128> guessToolChainBaseDir(StringRef SysRoot) {
+  SmallString<128> Result;
+  // Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk
+  StringRef Base = SysRoot;
+  Base = sys::path::parent_path(Base);
+  if (sys::path::filename(Base) != "SDKs")
+    return Result;
+  Result = Base;
+  Base = sys::path::parent_path(Base);
+  sys::path::append(Result, "Toolchains");
+  return Result;
+}
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JDevlieghere wrote:

Sounds good, but I still think we should move all that in a `DWARFLinker` directory (i.e. on the filesystem) to avoid the proliferation of `DWARFLinker*` libs. The Transforms directory for example is good prior art for that. 

https://github.com/llvm/llvm-project/pull/71205