[llvm-cxxfilt] Make --quote to work with "import thunk for" prefix

Author: keryell

llvm/test/tools/llvm-cxxfilt/quote.test

@@ -5,10 +5,13 @@ RUN: echo _Z3barv '"_Z3barv"' > %t
 RUN: echo '"_Z3barv"' _Z3barv >> %t
 // This is not mangled, thus it should not be quoted
 RUN: echo 'log()' >> %t
+// Check that an "import thunk for" prefix can be quoted along the demangled name
+RUN: echo __imp__ZSt6futureIvE >> %t
 RUN: llvm-cxxfilt --quote < %t | FileCheck --match-full-lines --check-prefix=CHECK-FILE %s
 CHECK-FILE: "bar()" "bar()"
 CHECK-FILE-NEXT: "bar()" "bar()"
 CHECK-FILE-NEXT: log()
+CHECK-FILE-NEXT: "import thunk for std::future<void>"
 
 // Check it works with cli symbols too. Since a quoted mangled name is not a
 // mangled name, it should be unchanged

llvm/tools/llvm-cxxfilt/llvm-cxxfilt.cpp

@@ -66,7 +66,7 @@ static void error(const Twine &Message) {
 }
 
 // Quote Undecorated with "" if asked for and not already followed by a '"'
-static std::string optionalQuote(std::string Undecorated,
+static std::string optionalQuote(const std::string &Undecorated,
                                  StringRef Delimiters) {
   if (Quote && (Delimiters.empty() || Delimiters[0] != '"'))
     return '"' + Undecorated + '"';
@@ -99,7 +99,7 @@ static std::string demangle(const std::string &Mangled, StringRef Delimiters) {
   }
 
   Result =
-      Undecorated ? Prefix + optionalQuote(Undecorated, Delimiters) : Mangled;
+      Undecorated ? optionalQuote(Prefix + Undecorated, Delimiters) : Mangled;
   free(Undecorated);
   return Result;
 }