On 10/25/2017 4:20 AM, Nathan Sidwell wrote:
On 10/25/2017 12:03 AM, Mukesh Kapoor wrote:
Thanks for pointing this out. Checking in the front end will be
difficult because the front end gets tokens after macro expansion. I
think the difficulty of fixing this bug comes because of the
requirement to maintain backward compatibility with the option
-Wliteral-suffix for -std=c++11.
IIUC the warning's intent is to catch cases of:
printf ("some format"PRIx64 ..., ...);
where there's no space between the string literals and the PRIx64
macro. I suspect it's very common for there to be a following
string-literal, so perhaps the preprocessor could detect:
<string-literal>NON-FN-MACRO<maybe-space><string-literal>
and warn on that sequence?
Yes, this can be done easily and this is also the usage mentioned in the
man page. I made this change in the compiler, bootstrapped it and ran
the tests. The following two tests fail after the fix:
g++.dg/cpp0x/Wliteral-suffix.C
g++.dg/cpp0x/warn_cxx0x4.C
Both tests have code similar to the following (from Wliteral-suffix.C):
#define BAR "bar"
#define PLUS_ONE + 1
char c = '3'PLUS_ONE; // { dg-warning "invalid suffix on literal" }
char s[] = "foo"BAR; // { dg-warning "invalid suffix on literal" }
Other compilers don't accept this code. Maybe I should just modify these
tests to have error messages instead of warnings and submit my revised fix?
Mukesh
nathan
