[gtest] Fix printing of StringRef and SmallString in assert messages.

Summary:
These are detected by gtest as containers, and so previously printed as e.g.
  { '.' (46, 0x2E), 's' (115, 0x73), 'e' (101, 0x65), 'c' (99, 0x63), '0' (48, 0x30) },

gtest itself overloads PrintTo for std::string and friends, we use the same mechanism.

Reviewers: labath

Subscribers: dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66520

llvm-svn: 369518

1 files changed, 29 insertions, 0 deletions

diff --git a/llvm/utils/unittest/googletest/include/gtest/internal/custom/gtest-printers.h b/llvm/utils/unittest/googletest/include/gtest/internal/custom/gtest-printers.h
index 60c1ea050b6..da2b418525c 100644
--- a/llvm/utils/unittest/googletest/include/gtest/internal/custom/gtest-printers.h
+++ b/llvm/utils/unittest/googletest/include/gtest/internal/custom/gtest-printers.h
@@ -39,4 +39,33 @@
 #ifndef GTEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_PRINTERS_H_
 #define GTEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_PRINTERS_H_
 
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringRef.h"
+#include <ostream>
+
+namespace llvm {
+
+// Printing of llvm String types.
+// gtest sees these as containers of char (they have nested iterator types),
+// so their operator<< is never considered unless we provide PrintTo().
+// PrintStringTo provides quotes and escaping, at the cost of a copy.
+
+inline void PrintTo(llvm::StringRef S, std::ostream *OS) {
+  *OS << ::testing::PrintToString(S.str());
+}
+// We need both SmallString<N> and SmallVectorImpl<char> overloads:
+//  - the SmallString<N> template is needed as overload resolution will
+//    instantiate generic PrintTo<T> rather than do derived-to-base conversion
+//  - but SmallVectorImpl<char> is sometimes the actual static type, in code
+//    that erases the small size
+template <unsigned N>
+inline void PrintTo(const SmallString<N> &S, std::ostream *OS) {
+  *OS << ::testing::PrintToString(std::string(S.data(), S.size()));
+}
+inline void PrintTo(const SmallVectorImpl<char> &S, std::ostream *OS) {
+  *OS << ::testing::PrintToString(std::string(S.data(), S.size()));
+}
+
+} // namespace llvm
+
 #endif  // GTEST_INCLUDE_GTEST_INTERNAL_CUSTOM_GTEST_PRINTERS_H_