Fix assertions and wrong output from StmtPrinter's string literal printing.

String literals (including unicode ones) can contain non-Unicode codepoints
if they were written using \x or similar. Write those out using \x, but be
careful that the following character can't be misinterpreted as part of the
\x escape sequence. Convert UTF-16 surrogate pairs back to codepoints before
rendering them.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@154069 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 46 insertions, 5 deletions

diff --git a/lib/AST/StmtPrinter.cpp b/lib/AST/StmtPrinter.cpp
index 7ebc1299f0..ef5eefb306 100644
--- a/lib/AST/StmtPrinter.cpp
+++ b/lib/AST/StmtPrinter.cpp
@@ -727,12 +727,40 @@ void StmtPrinter::VisitStringLiteral(StringLiteral *Str) {
   OS << '"';
   static char Hex[] = "0123456789ABCDEF";
 
+  unsigned LastSlashX = Str->getLength();
   for (unsigned I = 0, N = Str->getLength(); I != N; ++I) {
     switch (uint32_t Char = Str->getCodeUnit(I)) {
     default:
-      // FIXME: Is this the best way to print wchar_t?
+      // FIXME: Convert UTF-8 back to codepoints before rendering.
+
+      // Convert UTF-16 surrogate pairs back to codepoints before rendering.
+      // Leave invalid surrogates alone; we'll use \x for those.
+      if (Str->getKind() == StringLiteral::UTF16 && I != N - 1 &&
+          Char >= 0xd800 && Char <= 0xdbff) {
+        uint32_t Trail = Str->getCodeUnit(I + 1);
+        if (Trail >= 0xdc00 && Trail <= 0xdfff) {
+          Char = 0x10000 + ((Char - 0xd800) << 10) + (Trail - 0xdc00);
+          ++I;
+        }
+      }
+
       if (Char > 0xff) {
-        assert(Char <= 0x10ffff && "invalid unicode codepoint");
+        // If this is a wide string, output characters over 0xff using \x
+        // escapes. Otherwise, this is a UTF-16 or UTF-32 string, and Char is a
+        // codepoint: use \x escapes for invalid codepoints.
+        if (Str->getKind() == StringLiteral::Wide ||
+            (Char >= 0xd800 && Char <= 0xdfff) || Char >= 0x110000) {
+          // FIXME: Is this the best way to print wchar_t?
+          OS << "\\x";
+          int Shift = 28;
+          while ((Char >> Shift) == 0)
+            Shift -= 4;
+          for (/**/; Shift >= 0; Shift -= 4)
+            OS << Hex[(Char >> Shift) & 15];
+          LastSlashX = I;
+          break;
+        }
+
         if (Char > 0xffff)
           OS << "\\U00"
              << Hex[(Char >> 20) & 15]
@@ -745,13 +773,26 @@ void StmtPrinter::VisitStringLiteral(StringLiteral *Str) {
            << Hex[(Char >>  0) & 15];
         break;
       }
+
+      // If we used \x... for the previous character, and this character is a
+      // hexadecimal digit, prevent it being slurped as part of the \x.
+      if (LastSlashX + 1 == I) {
+        switch (Char) {
+          case '0': case '1': case '2': case '3': case '4':
+          case '5': case '6': case '7': case '8': case '9':
+          case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
+          case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
+            OS << "\"\"";
+        }
+      }
+
       if (Char <= 0xff && isprint(Char))
         OS << (char)Char;
       else  // Output anything hard as an octal escape.
         OS << '\\'
-        << (char)('0'+ ((Char >> 6) & 7))
-        << (char)('0'+ ((Char >> 3) & 7))
-        << (char)('0'+ ((Char >> 0) & 7));
+           << (char)('0' + ((Char >> 6) & 7))
+           << (char)('0' + ((Char >> 3) & 7))
+           << (char)('0' + ((Char >> 0) & 7));
       break;
     // Handle some common non-printable cases to make dumps prettier.
     case '\\': OS << "\\\\"; break;