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PE32+ binaries that use addresses > 1^32 have a problem in that the linker 

converts some address expressions into absolute values, but the PE format
only stores absolutes as 32-bits.  This is a partial solution which attempts
to convert such absolute values back to section relative ones instead.  It
fails for symbols like __image_base and ImageBase__, but it is unclear as to
whether these values are ever actually used by applications.

	PR ld/16821
	* peXXigen.c (abs_finder): New function.
	(_bfd_XXi_swap_sym_out): For absolute symbols with values larger
	than 1^32 try to convert them into section relative values
	instead.
This commit is contained in:
Nick Clifton 2014-04-11 16:02:52 +01:00
parent 58a84dcf29
commit 32ae0d80cd
2 changed files with 39 additions and 0 deletions
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8
bfd/ChangeLog
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@ -1,3 +1,11 @@
2014-04-11 Nick Clifton <nickc@redhat.com>
PR ld/16821
* peXXigen.c (abs_finder): New function.
(_bfd_XXi_swap_sym_out): For absolute symbols with values larger
than 1^32 try to convert them into section relative values
instead.
2014-04-11 Nick Clifton <nickc@redhat.com>
* bfd-in2.h: Regenerate.

31
bfd/peXXigen.c
View File

@ -207,6 +207,14 @@ _bfd_XXi_swap_sym_in (bfd * abfd, void * ext1, void * in1)
#endif
}
static bfd_boolean
abs_finder (bfd * abfd ATTRIBUTE_UNUSED, asection * sec, void * data)
{
bfd_vma abs_val = * (bfd_vma *) data;
return (sec->vma <= abs_val) && ((sec->vma + (1L << 32)) > abs_val);
}
unsigned int
_bfd_XXi_swap_sym_out (bfd * abfd, void * inp, void * extp)
{
@ -221,6 +229,29 @@ _bfd_XXi_swap_sym_out (bfd * abfd, void * inp, void * extp)
else
memcpy (ext->e.e_name, in->_n._n_name, SYMNMLEN);
/* The PE32 and PE32+ formats only use 4 bytes to hold the value of a
symbol. This is a problem on 64-bit targets where we can generate
absolute symbols with values >= 1^32. We try to work around this
problem by finding a section whose base address is sufficient to
reduce the absolute value to < 1^32, and then transforming the
symbol into a section relative symbol. This of course is a hack. */
if (sizeof (in->n_value) > 4
&& in->n_value > ((1L << 32) - 1)
&& in->n_scnum == -1)
{
asection * sec;
sec = bfd_sections_find_if (abfd, abs_finder, & in->n_value);
if (sec)
{
in->n_value -= sec->vma;
in->n_scnum = sec->target_index;
}
/* else: FIXME: The value is outside the range of any section. This
happens for __image_base__ and __ImageBase__ and maybe some other
symbols as well. We should find a way to handle these values. */
}
H_PUT_32 (abfd, in->n_value, ext->e_value);
H_PUT_16 (abfd, in->n_scnum, ext->e_scnum);