[LLVMdev] How to prevent LLVM from emitting R_X86_64_32 ELF relocations?
Yuri
yuri at rawbw.com
Fri Apr 26 20:02:27 PDT 2013
On 04/26/2013 19:50, Jiong Wang wrote:
>
>
> why do you want to prevent R_X86_64_32 generation? for 32bit dwarf,
> I think generation of R_X86_64_32 is reasonable.
>
> you can check http://dwarfstd.org/doc/DWARF4.pdf.
Because R_X86_64_32 elements are 4-byte addresses and can't be relocated
for the 64-bit address space over 32-bit limit.
Dwarf2 actually allows for both 32bit and 64-bit relocations. The
document, mentioned by you, explains this in section 7.5.1.1 on page
143. If the first DWORD of .debug_info section is 0xffffffff, then this
is 64-bit format.
But LLVM for some reason always chooses DWARF 32-bit format. This is why
I asked the question. Resulting relocable 64-bit objects can't be loaded
into addresses that are over 32-bit limit.
Yuri
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