Hi,
On Wed, 9 Jan 2019, Kurt Nalty wrote:
After firing up gdb, and tracing through a few combinations of static and
dynamically linked object files, I have determined that the segfaults were due
to usage of procedure linking tables
(.plt) with the statically linked process. The plt addresses are not corrected
when static loaded, but are corrected during dynamic linking. File
x86_64-gen.c, lines
630-634 were
#ifdef TCC_TARGET_PE
greloca(cur_text_section, vtop->sym, ind + 1, R_X86_64_PC32,
(int)(vtop->c.i-4));
#else
greloca(cur_text_section, vtop->sym, ind + 1, R_X86_64_PLT32,
(int)(vtop->c.i-4));
#endif
and are replaced by
greloca(cur_text_section, vtop->sym, ind + 1, R_X86_64_PC32,
(int)(vtop->c.i-4));
This restores correct static linking in uClibc-0-9.30 and musl
environments. Dynamic linking is unaffected, and continues to use
procedure link table jumps and calls.
It's still wrong. The relocation to use really should be PLT32, even
though it doesn't often make a difference (*).
I've now found time to look into this, i.e. static linking with uClibc. I
fixed some problems in mob and reverted your patch again. A simple hello
world now works statically with uClibc. Would be nice if you can retry
(and maybe with bigger examples :) ).
Ciao,
Michael.
* it's a historic mistake of the initial x86-64 psABI implementations that
PC32 relocs are sometimes used in place of PLT32 relocs (or from a
different point of view, that both relocations exist, and not only PC32).
_______________________________________________
Tinycc-devel mailing list
[email protected]
https://lists.nongnu.org/mailman/listinfo/tinycc-devel
