Does ggc-page.c require MMAP_DEV_ZERO and MMAP_ANON?

[H. J. Lu]

I notice a strange gcc bug where I got bootstrap comparison failure
when MMAP_DEV_ZERO and MMAP_ANON weren't available due to an ia64
kernel bug. I got

Gcc from gcc-3_3-rhl-branch in cvs on Sun Jun 22 16:04:11 UTC 2003
failed to bootstrap under Linux/ia64 on Itanium 2 running RHAS 2.1.
The last known working one was checked out on Wed Jun 18 15:04:48 UTC
2003. The same gcc bootstrapped successfully on Itanium 1 running
RHAS 2.1. The error message is

Bootstrap comparison failure!
java/decl.o differs
make[3]: *** [compare] Error 1
make[3]: Leaving directory `/export/build/gnu/gcc-3.3-redhat/build-ia64-
linux/gcc'
make[2]: *** [bootstrap] Error 2
make[2]: Leaving directory `/export/build/gnu/gcc-3.3-redhat/build-ia64-linux'
Command exited with non-zero status 2

t turned out that it is a gcc bug exposed by a kernel bug. When I
configured gcc, I got

checking for working mmap from /dev/zero... no
checking for working mmap with MAP_ANON(YMOUS)... no

As the result, I had

/* #undef HAVE_MMAP_DEV_ZERO */
/* #undef HAVE_MMAP_ANON */
#define HAVE_MMAP_FILE 1

in auto-host.h. Apparently, ggc-page.c doesn't work too well with
this configuration.


H.J.