[clang] [llvm] Make sanitizer special case list slash-agnostic (PR #149886)

[James Y Knight via llvm-commits]

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@@ -57,9 +59,12 @@ Error SpecialCaseList::Matcher::insert(StringRef Pattern, unsigned LineNumber,
   auto Glob = std::make_unique<Matcher::Glob>();
   Glob->Name = Pattern.str();
   Glob->LineNo = LineNumber;
+  // Backslashes are valid in posix-style filenames.
+  bool IsSlashAgnostic = Triple(sys::getDefaultTargetTriple()).isOSWindows();
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jyknight wrote:

Because we're talking about source files being read by the compiler, the interpretation of paths should be based on whether the compiler is built for and running on windows -- not based on what target the compiler defaults to build code for. 

You could detect that with `#ifdef _WIN32`. But even better is to use the abstraction `llvm::sys::path::is_style_windows(llvm::sys::path::native)`, which does the same, but in a more self-documenting manner.

https://github.com/llvm/llvm-project/pull/149886