[Bug c++/52538] Extend C++11 UDLs to be compatible with inttypes.h macros

[aaw at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52538

--- Comment #3 from Ollie Wild <aaw at gcc dot gnu.org> 2012-04-27 14:29:39 UTC ---
Author: aaw
Date: Fri Apr 27 14:29:32 2012
New Revision: 186909

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=186909
Log:
Add new option, -Wliteral-suffix.

This option, which is enabled by default, causes the preprocessor to warn
when a string or character literal is followed by a ud-suffix which does
not begin with an underscore.  According to [lex.ext]p10, this is
ill-formed.

Also modifies the preprocessor to treat such ill-formed suffixes as separate
preprocessing tokens.  This is consistent with the Clang front end (see
http://llvm.org/viewvc/llvm-project?view=rev&revision=152287), and enables
backwards compatibility with code that uses formatting macros from
<inttypes.h>, as in the following code block:

  int main() {
    int64_t i64 = 123;
    printf("My int64: %"PRId64"\n", i64);
  }

Google ref b/6377711.

2012-04-27   Ollie Wild  <aaw@google.com>

    PR c++/52538
    * gcc/c-family/c-common.c: Add CPP_W_LITERAL_SUFFIX mapping.
    * gcc/c-family/c-opts.c (c_common_handle_option): Handle
    OPT_Wliteral_suffix.
    * gcc/c-family/c.opt: Add Wliteral-suffix.
    * gcc/doc/invoke.texi (Wliteral-suffix): Document new option.
    * gcc/testsuite/g++.dg/cpp0x/Wliteral-suffix.c: New test.
    * libcpp/include/cpplib.h (struct cpp_options): Add new field,
    warn_literal_suffix.
    (CPP_W_LITERAL_SUFFIX): New enum.
    * libcpp/init.c (cpp_create_reader): Default initialization of
    warn_literal_suffix.
    * libcpp/lex.c (lex_raw_string): Treat user-defined literals which
    don't begin with '_' as separate tokens and produce a warning.
    (lex_string): Ditto.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/Wliteral-suffix.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/c-family/ChangeLog
    trunk/gcc/c-family/c-common.c
    trunk/gcc/c-family/c-opts.c
    trunk/gcc/c-family/c.opt
    trunk/gcc/doc/invoke.texi
    trunk/gcc/testsuite/ChangeLog
    trunk/libcpp/ChangeLog
    trunk/libcpp/include/cpplib.h
    trunk/libcpp/init.c
    trunk/libcpp/lex.c