YAMLIO: Fix serialization of strings with embedded nuls

Summary:
A bug/typo in Output::scalarString caused us to round-trip a StringRef
through a const char *. This meant that any strings with embedded nuls
were unintentionally cut short at the first such character. (It also
could have caused accidental buffer overruns, but it seems that all
StringRefs coming into this functions were formed from null-terminated
strings.)

This patch fixes the bug and adds an appropriate test.

Reviewers: sammccall, jhenderson

Subscribers: kristina, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60505

llvm-svn: 358176

1 files changed, 6 insertions, 6 deletions

diff --git a/llvm/lib/Support/YAMLTraits.cpp b/llvm/lib/Support/YAMLTraits.cpp
index 4b5bf6ad30d3..e7932fe4239c 100644
--- a/llvm/lib/Support/YAMLTraits.cpp
+++ b/llvm/lib/Support/YAMLTraits.cpp
@@ -660,11 +660,6 @@ void Output::scalarString(StringRef &S, QuotingType MustQuote) {
     return;
   }
 
-  unsigned i = 0;
-  unsigned j = 0;
-  unsigned End = S.size();
-  const char *Base = S.data();
-
   const char *const Quote = MustQuote == QuotingType::Single ? "'" : "\"";
   output(Quote); // Starting quote.
 
@@ -672,11 +667,16 @@ void Output::scalarString(StringRef &S, QuotingType MustQuote) {
   // present, and will be escaped using a variety of unicode-scalar and special short-form
   // escapes. This is handled in yaml::escape.
   if (MustQuote == QuotingType::Double) {
-    output(yaml::escape(Base, /* EscapePrintable= */ false));
+    output(yaml::escape(S, /* EscapePrintable= */ false));
     outputUpToEndOfLine(Quote);
     return;
   }
 
+  unsigned i = 0;
+  unsigned j = 0;
+  unsigned End = S.size();
+  const char *Base = S.data();
+
   // When using single-quoted strings, any single quote ' must be doubled to be escaped.
   while (j < End) {
     if (S[j] == '\'') {                    // Escape quotes.