family of functions. Previous functionality only included checking to
see if the format string was a string literal. Now we check parse the
format string (if it is a literal) and perform the following checks:
(1) Warn if: number conversions (e.g. "%d") != number data arguments.
(2) Warn about missing format strings (e.g., "printf()").
(3) Warn if the format string is not a string literal.
(4) Warn about the use se of '%n' conversion. This conversion is
discouraged for security reasons.
(5) Warn about malformed conversions. For example '%;', '%v'; these
are not valid.
(6) Warn about empty format strings; e.g. printf(""). Although these
can be optimized away by the compiler, they can be indicative of
broken programmer logic. We may need to add additional support to
see when such cases occur within macro expansion to avoid false
positives.
(7) Warn if the string literal is wide; e.g. L"%d".
(8) Warn if we detect a '\0' character WITHIN the format string.
Test cases are included.
llvm-svn: 41076
"I've coded up some support in clang to flag warnings for non-constant format strings used in calls to printf-like functions (all the functions listed in "man fprintf"). Non-constant format strings are a source of many security exploits in C/C++ programs, and I believe are currently detected by gcc using the flag -Wformat-nonliteral."
llvm-svn: 41003
