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Re: x86-64 push / jmp / mov of undefined label results in bad relocation for position-independent code
- From: "Jan Beulich" <JBeulich at suse dot com>
- To: "Bruno Loff" <bruno dot loff at gmail dot com>
- Cc: <binutils at sourceware dot org>
- Date: Tue, 22 Aug 2017 05:42:21 -0600
- Subject: Re: x86-64 push / jmp / mov of undefined label results in bad relocation for position-independent code
- Authentication-results: sourceware.org; auth=none
- References: <CAGOfsMg_wV92F+cnvdmMh9HyVytu0N6PUDo=Tz23GcVzZPruzw@mail.gmail.com>
>>> On 22.08.17 at 13:25, <firstname.lastname@example.org> wrote:
> When compiling an x86-64 assembly file which contains a `push`, `jmp`
> or `mov` instruction having an undefined label as an operand, `as`
> generates a relocation of type `R_X86_64_32S`, which is only 32bit
> long, i.e., it is too short for position-independent code (since such
> code might be loaded onto a position outside the 32-bit address
Of course. All three named mnemonics have only 32-bit immediate
operands, so a wider relocation cannot possibly be used with them.
You'll need to go through a register, using movabs or lea to load
the intended value into it.