https://sourceware.org/bugzilla/show_bug.cgi?id=22269
--- Comment #10 from H.J. Lu <hjl.tools at gmail dot com> --- (In reply to Alan Modra from comment #9) > > Since call is PC relative, this doesn't branch to address 0. > > I don't see why this matters. A symbol that resolves to zero without > dynamic relocs in a PIE or shared lib results in an address of zero. If > that zero is in a PC-relative instruction then you get zero relative to the > shared library or PIE base. Typical code for dealing with weakly defined > functions like > if (foo) > foo (); > will give you a load of zero (absolute) on the condition, but a relative > zero for the call. If there is a program bug: foo (); without if (foo) check, PC relative branch to base may not crash and may lead to undesired behavior. > > This doesn't work with > > > > -pie --no-dynamic-linker -z dynamic-undefined-weak > > Define "doesn't work". I would have said that combination of options ought > to result in a dynamic reloc for "func" on the original testcase. Which is > what powerpc will do. It may not work in the runtime environment for static > PIE, but that's a different issue. By passing -z dynamic-undefined-weak you > asked for dynamic relocs! -z dynamic-undefined-weak applies to there is a DT_NEEDED entry which may provide definition for undefined weak reference at run-time. For static PIE, weak undefined should always be resolved to 0. -- You are receiving this mail because: You are on the CC list for the bug. _______________________________________________ bug-binutils mailing list bug-binutils@gnu.org https://lists.gnu.org/mailman/listinfo/bug-binutils
