On Fri, Dec 01, 2017 at 03:16:23PM -0500, Jason Merrill wrote:
> commit e39b7d506d236ce7ef9f64d1bcf0b384bb2d8038
> Author: Jason Merrill <ja...@redhat.com>
> Date: Fri Dec 1 07:45:03 2017 -0500
>
> PR c++/79228 - extensions hide C++14 complex literal operators
>
> libcpp/
> * expr.c (interpret_float_suffix): Ignore 'i' in C++14 and up.
> (interpret_int_suffix): Likewise.
> gcc/cp/
> * parser.c (cp_parser_userdef_numeric_literal): Be helpful about
> 'i' in C++14 and up.
>
> + /* In C++14 and up these suffixes are in the standard library, so treat
> + them as user-defined literals. */
> + if (CPP_OPTION (pfile, cplusplus)
> + && CPP_OPTION (pfile, lang) > CLK_CXX11
> + && (!memcmp (orig_s, "i", orig_len)
> + || !memcmp (orig_s, "if", orig_len)
> + || !memcmp (orig_s, "il", orig_len)))
This doesn't seem right, it will invoke UB if orig_len > 2 by potentially
accessing bytes beyond 'i' and '\0' in "i" (and for orig_len > 3 also after
"if" or "il").
If you only want to return 0 if orig_len bytes starting at orig_s are 'i'
or 'i' 'f' or 'i' 'l', then I'd write instead as in the patch below.
Or if memcmp is more readable, at least check orig_len first.
> + /* In C++14 and up these suffixes are in the standard library, so treat
> + them as user-defined literals. */
> + if (CPP_OPTION (pfile, cplusplus)
> + && CPP_OPTION (pfile, lang) > CLK_CXX11
> + && (!memcmp (s, "i", orig_len)
> + || !memcmp (s, "if", orig_len)
> + || !memcmp (s, "il", orig_len)))
Similarly. Additionally, "if" can't happen here, because we don't allow 'f'
among suffixes.
So, ok for trunk if it passes testing, or some other form thereof?
2017-12-05 Jakub Jelinek <ja...@redhat.com>
PR c++/79228
* expr.c (interpret_float_suffix): Avoid memcmp.
(interpret_int_suffix): Likewise. Don't check for if.
--- libcpp/expr.c.jj 2017-12-01 22:13:24.000000000 +0100
+++ libcpp/expr.c 2017-12-05 13:26:57.019683785 +0100
@@ -280,9 +280,10 @@ interpret_float_suffix (cpp_reader *pfil
them as user-defined literals. */
if (CPP_OPTION (pfile, cplusplus)
&& CPP_OPTION (pfile, lang) > CLK_CXX11
- && (!memcmp (orig_s, "i", orig_len)
- || !memcmp (orig_s, "if", orig_len)
- || !memcmp (orig_s, "il", orig_len)))
+ && orig_s[0] == 'i'
+ && (orig_len == 1
+ || (orig_len == 2
+ && (orig_s[1] == 'f' || orig_s[1] == 'l'))))
return 0;
}
@@ -345,9 +346,8 @@ interpret_int_suffix (cpp_reader *pfile,
them as user-defined literals. */
if (CPP_OPTION (pfile, cplusplus)
&& CPP_OPTION (pfile, lang) > CLK_CXX11
- && (!memcmp (s, "i", orig_len)
- || !memcmp (s, "if", orig_len)
- || !memcmp (s, "il", orig_len)))
+ && s[0] == 'i'
+ && (orig_len == 1 || (orig_len == 2 && s[1] == 'l')))
return 0;
}
Jakub
