PATCH: [perl #119601] Bleadperl breaks ETHER/Devel-Declare

I will not otherwise mention that stealing .c code from the core is a
dangerous practice.

This is actually a bug in the module, which had been masked until now.
The first two parameters to utf8_to_uvchr_buf() are both U8*.  But  both
's' and PL_bufend are char*.  The 's' has a cast to U8* in the failing
line, but not PL_bufend.

Interestingly, the line in the official toke.c (introduced in 4b88fb76)
has always been right, so the stealer didn't copy it correctly.

What de69f3af3 did was turn this former function call into a macro that
manipulates the parameters and calls another function, thereby removing
a layer of function call overhead.  The manipulation involves
subtracting 's' from PL_bufend, and this fails to compile due to the
missing cast on the latter parameter.

The problem goes away if the macro casts both parameters to U8*, and
that is what this commit does.

diff --git a/utf8.h b/utf8.h
index 1bca7e8..7036488 100644 (file)
--- a/utf8.h
+++ b/utf8.h
@@ -43,7 +43,7 @@
 #define uvchr_to_utf8_flags(d,uv,flags)                                        \
                             uvoffuni_to_utf8_flags(d,NATIVE_TO_UNI(uv),flags)
 #define utf8_to_uvchr_buf(s, e, lenp)                                          \
-                     utf8n_to_uvchr(s, (e) - (s), lenp,                        \
+                     utf8n_to_uvchr(s, (U8*)(e) - (U8*)(s), lenp,              \
                                     ckWARN_d(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY)
 
 #define to_uni_fold(c, p, lenp) _to_uni_fold_flags(c, p, lenp, FOLD_FLAGS_FULL)