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diff --git a/third_party/llvm-project/include/llvm/Support/Regex.h b/third_party/llvm-project/include/llvm/Support/Regex.h
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+++ b/third_party/llvm-project/include/llvm/Support/Regex.h
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+//===-- Regex.h - Regular Expression matcher implementation -*- C++ -*-----===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a POSIX regular expression matcher.  Both Basic and
+// Extended POSIX regular expressions (ERE) are supported.  EREs were extended
+// to support backreferences in matches.
+// This implementation also supports matching strings with embedded NUL chars.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_REGEX_H
+#define LLVM_SUPPORT_REGEX_H
+
+#include <string>
+
+struct llvm_regex;
+
+namespace llvm {
+  class StringRef;
+  template<typename T> class SmallVectorImpl;
+
+  class Regex {
+  public:
+    enum {
+      NoFlags=0,
+      /// Compile for matching that ignores upper/lower case distinctions.
+      IgnoreCase=1,
+      /// Compile for newline-sensitive matching. With this flag '[^' bracket
+      /// expressions and '.' never match newline. A ^ anchor matches the
+      /// null string after any newline in the string in addition to its normal
+      /// function, and the $ anchor matches the null string before any
+      /// newline in the string in addition to its normal function.
+      Newline=2,
+      /// By default, the POSIX extended regular expression (ERE) syntax is
+      /// assumed. Pass this flag to turn on basic regular expressions (BRE)
+      /// instead.
+      BasicRegex=4
+    };
+
+    Regex();
+    /// Compiles the given regular expression \p Regex.
+    ///
+    /// \param Regex - referenced string is no longer needed after this
+    /// constructor does finish.  Only its compiled form is kept stored.
+    Regex(StringRef Regex, unsigned Flags = NoFlags);
+    Regex(const Regex &) = delete;
+    Regex &operator=(Regex regex) {
+      std::swap(preg, regex.preg);
+      std::swap(error, regex.error);
+      return *this;
+    }
+    Regex(Regex &&regex);
+    ~Regex();
+
+    /// isValid - returns the error encountered during regex compilation, if
+    /// any.
+    bool isValid(std::string &Error) const;
+    bool isValid() const { return !error; }
+
+    /// getNumMatches - In a valid regex, return the number of parenthesized
+    /// matches it contains.  The number filled in by match will include this
+    /// many entries plus one for the whole regex (as element 0).
+    unsigned getNumMatches() const;
+
+    /// matches - Match the regex against a given \p String.
+    ///
+    /// \param Matches - If given, on a successful match this will be filled in
+    /// with references to the matched group expressions (inside \p String),
+    /// the first group is always the entire pattern.
+    ///
+    /// \param Error - If non-null, any errors in the matching will be recorded
+    /// as a non-empty string. If there is no error, it will be an empty string.
+    ///
+    /// This returns true on a successful match.
+    bool match(StringRef String, SmallVectorImpl<StringRef> *Matches = nullptr,
+               std::string *Error = nullptr) const;
+
+    /// sub - Return the result of replacing the first match of the regex in
+    /// \p String with the \p Repl string. Backreferences like "\0" in the
+    /// replacement string are replaced with the appropriate match substring.
+    ///
+    /// Note that the replacement string has backslash escaping performed on
+    /// it. Invalid backreferences are ignored (replaced by empty strings).
+    ///
+    /// \param Error If non-null, any errors in the substitution (invalid
+    /// backreferences, trailing backslashes) will be recorded as a non-empty
+    /// string. If there is no error, it will be an empty string.
+    std::string sub(StringRef Repl, StringRef String,
+                    std::string *Error = nullptr) const;
+
+    /// If this function returns true, ^Str$ is an extended regular
+    /// expression that matches Str and only Str.
+    static bool isLiteralERE(StringRef Str);
+
+    /// Turn String into a regex by escaping its special characters.
+    static std::string escape(StringRef String);
+
+  private:
+    struct llvm_regex *preg;
+    int error;
+  };
+}
+
+#endif // LLVM_SUPPORT_REGEX_H