[llvm-cxxfilt] Replace isalnum with isAlnum from StringExtras

D104366 introduced a new llvm-cxxfilt test with non-ASCII characters,
which caused a failure on llvm-clang-x86_64-expensive-checks-win
builder, with a stack trace suggesting issue in a call to isalnum.

The argument to isalnum should be either EOF or a value that is
representable in the type unsigned char. The llvm-cxxfilt does not
perform a cast from char to unsigned char before the call, so the
value might be out of valid range.

Replace the call to isalnum with isAlnum from StringExtras, which takes
a char as the argument. This also makes the check independent of the
current locale.

Differential Revision: https://reviews.llvm.org/D110986

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/tools/llvm-cxxfilt/llvm-cxxfilt.cpp b/llvm/tools/llvm-cxxfilt/llvm-cxxfilt.cpp
index d8bf8db..0a6d4b5 100644
--- a/llvm/tools/llvm-cxxfilt/llvm-cxxfilt.cpp
+++ b/llvm/tools/llvm-cxxfilt/llvm-cxxfilt.cpp
@@ -128,7 +128,7 @@ static void SplitStringDelims(
 static bool IsLegalItaniumChar(char C) {
   // Itanium CXX ABI [External Names]p5.1.1:
   // '$' and '.' in mangled names are reserved for private implementations.
-  return isalnum(C) || C == '.' || C == '$' || C == '_';
+  return isAlnum(C) || C == '.' || C == '$' || C == '_';
 }
 
 // If 'Split' is true, then 'Mangled' is broken into individual words and each