[Bug driver/65639] New: -nostdlib/-nodefaultlibs should not affect ASan runtime

[earthdok at google dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65639

            Bug ID: 65639
           Summary: -nostdlib/-nodefaultlibs should not affect ASan
                    runtime
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: driver
          Assignee: unassigned at gcc dot gnu.org
          Reporter: earthdok at google dot com
                CC: jakub at gcc dot gnu.org, kcc at gcc dot gnu.org,
                    samsonov at google dot com

In GCC trunk, if -nostdlib/-nodefaultlibs is passed together with
-fsanitize=address, the ASan runtime is not linked. Clang had the same behavior
briefly but ended up reverting to the old behavior (i.e. those flags do not
affect the ASan runtime):

http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20141020/117217.html
https://code.google.com/p/address-sanitizer/issues/detail?id=344

One use case where GCC's behavior is problematic is building an
ASan-instrumented glibc. Some executables are linked with -nostdlib and
explicitly linked against the just-built libc.so.6; -fsanitize=address causes
those build steps to fail due to unresolved ASan symbols.