On Jan 4, 2017, Martin Sebor <mse...@gmail.com> wrote:
> The manual recommends to use a length modifier to constrain the length
> of output to that of a narrower type:
> sprintf (xname, "<U%4hx>", ((unsigned short)((uintptr_t)(t) & 0xffff)));
> This should work even without optimization.
It might not work if short happens to be wider than 16 bits, but I guess
we need not worry about that at -O1.
In stage2 of bootstrap-O1, the code that warns if sprintf might
overflow its output buffer cannot tell that an unsigned value narrowed
to 16 bits will fit in 4 bytes with %4x.
Converting the value to 'unsigned short' makes it obvious that it
fits, at least on machines with 16-bit shorts.
Regstrapped on x86_64-linux-gnu and i686-linux-gnu. Ok to install?
for gcc/c-family/ChangeLog
* c-pretty-print.c (pp_c_tree_decl_identifier): Convert 16-bit
value to unsigned short to fit in 4 hex digits without
warnings.
---
gcc/c-family/c-pretty-print.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gcc/c-family/c-pretty-print.c b/gcc/c-family/c-pretty-print.c
index 90428ca..07fdbae 100644
--- a/gcc/c-family/c-pretty-print.c
+++ b/gcc/c-family/c-pretty-print.c
@@ -2400,7 +2400,7 @@ pp_c_tree_decl_identifier (c_pretty_printer *pp, tree t)
else
{
static char xname[8];
- sprintf (xname, "<U%4x>", ((unsigned)((uintptr_t)(t) & 0xffff)));
+ sprintf (xname, "<U%4hx>", ((unsigned short)((uintptr_t)(t) & 0xffff)));
name = xname;
}
--
Alexandre Oliva, freedom fighter http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/ FSF Latin America board member
Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer
