[Sema] Handle UTF-8 invalid format string specifiers
Improve invalid format string specifier handling by printing out
invalid specifiers characters with \x, \u and \U. Previously clang
would print gargabe whenever the character is unprintable.
Example, before:
NSLog(@"%\u25B9"); => warning: invalid conversion specifier ' [-Wformat-invalid-specifier]
after:
NSLog(@"%\u25B9"); => warning: invalid conversion specifier '\u25b9' [-Wformat-invalid-specifier]
Differential Revision: http://reviews.llvm.org/D18296
rdar://problem/24672159
llvm-svn: 264752
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index cc261e0..062041e 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -36,6 +36,8 @@
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallBitVector.h"
#include "llvm/ADT/SmallString.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/Locale.h"
#include "llvm/Support/ConvertUTF.h"
#include "llvm/Support/raw_ostream.h"
#include <limits>
@@ -3976,12 +3978,41 @@
// gibberish when trying to match arguments.
keepGoing = false;
}
-
- EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion)
- << StringRef(csStart, csLen),
- Loc, /*IsStringLocation*/true,
- getSpecifierRange(startSpec, specifierLen));
-
+
+ StringRef Specifier(csStart, csLen);
+
+ // If the specifier in non-printable, it could be the first byte of a UTF-8
+ // sequence. In that case, print the UTF-8 code point. If not, print the byte
+ // hex value.
+ std::string CodePointStr;
+ if (!llvm::sys::locale::isPrint(*csStart)) {
+ UTF32 CodePoint;
+ const UTF8 **B = reinterpret_cast<const UTF8 **>(&csStart);
+ const UTF8 *E =
+ reinterpret_cast<const UTF8 *>(csStart + csLen);
+ ConversionResult Result =
+ llvm::convertUTF8Sequence(B, E, &CodePoint, strictConversion);
+
+ if (Result != conversionOK) {
+ unsigned char FirstChar = *csStart;
+ CodePoint = (UTF32)FirstChar;
+ }
+
+ llvm::raw_string_ostream OS(CodePointStr);
+ if (CodePoint < 256)
+ OS << "\\x" << llvm::format("%02x", CodePoint);
+ else if (CodePoint <= 0xFFFF)
+ OS << "\\u" << llvm::format("%04x", CodePoint);
+ else
+ OS << "\\U" << llvm::format("%08x", CodePoint);
+ OS.flush();
+ Specifier = CodePointStr;
+ }
+
+ EmitFormatDiagnostic(
+ S.PDiag(diag::warn_format_invalid_conversion) << Specifier, Loc,
+ /*IsStringLocation*/ true, getSpecifierRange(startSpec, specifierLen));
+
return keepGoing;
}