[clang-format] NFC Fix uninitialized memory problem

[sstwcw]

Summary

The setLength function checks for the token kind which could be
uninitialized in the previous version.

The problem was introduced in 2e32ff106e.

[sstwcw]

This problem was found by the build bot after I pushed the buggy code.
https://lab.llvm.org/buildbot#builders/5/builds/25268
It looks like uninitialized memory was not checked when I ran ninja check-clang-format locally. Am I missing some configuration?

[owenpan]

Can you remove NFC? IMO, fixing a memory error is not NFC.

clang/lib/Format/FormatTokenLexer.cpp

if (!VerilogToken.match(StringRef(Start, Lex->getBuffer().end() - Start),
     return false;
   }
   // There is a null byte at the end of the buffer, so we don't have to check
   // Start[1] is within the buffer.
   if (Start[0] == '\\' && (Start[1] == '\r' || Start[1] == '\n'))
     return false;
   size_t Len = Matches[0].size();
 
-  Tok.setLength(Len);
-  Tok.setLocation(Lex->getSourceLocation(Start, Len));
   // The kind has to be an identifier so we can match it against those defined
-  // in Keywords.
+  // in Keywords. The kind has to be set before the length because the setLength
+  // function checks that the kind is not an annotation.
   Tok.setKind(tok::raw_identifier);
+  Tok.setLength(Len);
+  Tok.setLocation(Lex->getSourceLocation(Start, Len));
   Tok.setRawIdentifierData(Start);
   Lex->seek(Lex->getCurrentBufferOffset() + Len, /*IsAtStartofline=*/false);
   return true;
 }
 
 void FormatTokenLexer::readRawToken(FormatToken &Tok) {
   // For Verilog, first see if there is a special token, and fall back to the
   // normal lexer if there isn't one.