Index: llvm/test/tools/llvm-cxxfilt/delimiters.test
===================================================================
--- /dev/null
+++ llvm/test/tools/llvm-cxxfilt/delimiters.test
@@ -0,0 +1,62 @@
+RUN: echo ",,_Z3Foo!" \
+RUN:      "_Z3Foo\""  \
+RUN:      "_Z3Foo\""  \
+RUN:      "_Z3Foo#"   \
+RUN:      "_Z3Foo%"   \
+RUN:      "_Z3Foo&"   \
+RUN:      "_Z3Foo'"   \
+RUN:      "_Z3Foo("   \
+RUN:      "_Z3Foo)"   \
+RUN:      "_Z3Foo*"   \
+RUN:      "_Z3Foo+"   \
+RUN:      "_Z3Foo,"   \
+RUN:      "_Z3Foo-"   \
+RUN:      "_Z3Foo/"   \
+RUN:      "_Z3Foo:"   \
+RUN:      "_Z3Foo;"   \
+RUN:      "_Z3Foo<"   \
+RUN:      "_Z3Foo="   \
+RUN:      "_Z3Foo>"   \
+RUN:      "_Z3Foo?"   \
+RUN:      "_Z3Foo@"   \
+RUN:      "_Z3Foo["   \
+RUN:      "_Z3Foo\\"  \
+RUN:      "_Z3Foo]"   \
+RUN:      "_Z3Foo^"   \
+RUN:      "_Z3Foo\`"  \
+RUN:      "_Z3Foo{"   \
+RUN:      "_Z3Foo|"   \
+RUN:      "_Z3Foo}"   \
+RUN:      "_Z3Foo~,," \
+RUN:      '_Z3Foo$ ._Z3Foo' | llvm-cxxfilt | FileCheck %s
+
+CHECK: ,,Foo!
+CHECK: Foo"
+CHECK: Foo#
+CHECK: Foo%
+CHECK: Foo&
+CHECK: Foo'
+CHECK: Foo(
+CHECK: Foo)
+CHECK: Foo*
+CHECK: Foo+
+CHECK: Foo,
+CHECK: Foo-
+CHECK: Foo/
+CHECK: Foo:
+CHECK: Foo;
+CHECK: Foo<
+CHECK: Foo=
+CHECK: Foo>
+CHECK: Foo?
+CHECK: Foo@
+CHECK: Foo[
+CHECK: Foo\
+CHECK: Foo]
+CHECK: Foo^
+CHECK: Foo`
+CHECK: Foo{
+CHECK: Foo|
+CHECK: Foo}
+CHECK: Foo~,,
+CHECK: _Z3Foo$ ._Z3Foo
Index: llvm/tools/llvm-cxxfilt/llvm-cxxfilt.cpp
===================================================================
--- llvm/tools/llvm-cxxfilt/llvm-cxxfilt.cpp
+++ llvm/tools/llvm-cxxfilt/llvm-cxxfilt.cpp
@@ -78,19 +78,52 @@
   return Result;
 }
 
+// Split 'Source' on any character that fails to pass 'IsLegalChar'.  The
+// returned vector consists of pairs where 'first' is the delimited word, and
+// 'second' are the delimiters following that word.
+static void SplitStringDelims(
+    StringRef Source,
+    SmallVectorImpl<std::pair<StringRef, StringRef>> &OutFragments,
+    function_ref<bool(char)> IsLegalChar) {
+  // The beginning of the string.
+  StringRef::iterator First = Source.begin();
+
+  // Obtain any leading delimiters.
+  StringRef::iterator Start =
+      std::find_if(Source.begin(), Source.end(), IsLegalChar);
+  if (Start != First)
+    OutFragments.push_back({"", Source.slice(0, Start - First)});
+
+  // Capture each word and the delimiters following that word.
+  while (Start != Source.end()) {
+    Start = std::find_if(Start, Source.end(), IsLegalChar);
+    StringRef::iterator End =
+        std::find_if_not(Start, Source.end(), IsLegalChar);
+    StringRef::iterator DEnd = std::find_if(End, Source.end(), IsLegalChar);
+    OutFragments.push_back({Source.slice(Start - First, End - First),
+                            Source.slice(End - First, DEnd - First)});
+    Start = DEnd;
+  }
+}
+
+// This returns true if 'C' is a character that can show up in an
+// Itanium-mangled string.
+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 == '_';
+}
+
 // If 'Split' is true, then 'Mangled' is broken into individual words and each
 // word is demangled.  Otherwise, the entire string is treated as a single
 // mangled item.  The result is output to 'OS'.
 static void demangleLine(llvm::raw_ostream &OS, StringRef Mangled, bool Split) {
   std::string Result;
   if (Split) {
-    SmallVector<StringRef, 16> Words;
-    SplitString(Mangled, Words);
-    for (auto Word : Words)
-      Result += demangle(OS, Word) + ' ';
-    // Remove the trailing space character.
-    if (Result.back() == ' ')
-      Result.pop_back();
+    SmallVector<std::pair<StringRef, StringRef>, 16> Words;
+    SplitStringDelims(Mangled, Words, IsLegalItaniumChar);
+    for (auto &Word : Words)
+      Result += demangle(OS, Word.first) + Word.second.str();
   } else
     Result = demangle(OS, Mangled);
   OS << Result << '\n';