Fix printEscapedString: Hex escape is \xHH, not \HH.

[Mogball]

llvm/lib/Support/StringExtras.cpp

70

Can you add a test case for this?

[matthiaskramm]

Adjust test case.

[matthiaskramm]

Redoing this change, since (at least) MLIR uses \HH for hex escapes.

llvm/lib/Support/StringExtras.cpp

 void llvm::printEscapedString(StringRef Name, raw_ostream &Out) {
   for (unsigned i = 0, e = Name.size(); i != e; ++i) {
     unsigned char C = Name[i];
     if (C == '\\')
       Out << '\\' << C;
     else if (isPrint(C) && C != '"')
       Out << C;
     else
-      Out << '\\' << hexdigit(C >> 4) << hexdigit(C & 0x0F);
+      Out << "\\x" << hexdigit(C >> 4) << hexdigit(C & 0x0F);
   }
 }
 
 void llvm::printHTMLEscaped(StringRef String, raw_ostream &Out) {
   for (char C : String) {
     if (C == '&')
       Out << "&amp;";
     else if (C == '<')

llvm/unittests/ADT/StringExtrasTest.cpp

TEST(StringExtrasTest, printLowerCase) {
   printLowerCase("ABCdefg01234.,&!~`'}\"", OS);
   EXPECT_EQ("abcdefg01234.,&!~`'}\"", OS.str());
 }
 
 TEST(StringExtrasTest, printEscapedString) {
   std::string str;
   raw_string_ostream OS(str);
   printEscapedString("ABCdef123&<>\\\"'\t", OS);
-  EXPECT_EQ("ABCdef123&<>\\\\\\22'\\09", OS.str());
+  EXPECT_EQ("ABCdef123&<>\\\\\\x22'\\x09", OS.str());
 }
 
 TEST(StringExtrasTest, printHTMLEscaped) {
   std::string str;
   raw_string_ostream OS(str);
   printHTMLEscaped("ABCdef123&<>\"'", OS);
   EXPECT_EQ("ABCdef123&amp;&lt;&gt;&quot;&apos;", OS.str());
 }