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authorJan Beulich <jbeulich@suse.com>2023-08-25 14:56:44 +0200
committerJan Beulich <jbeulich@suse.com>2023-08-25 14:56:44 +0200
commit67694446f772ae95d330419eb6d01e38e6d24612 (patch)
tree21119de766ad7554bd06371b5713ab4f58917c96 /bfd/coffcode.h
parent183440b0aa1cd752c324a2f4c16a620bd938d9ad (diff)
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bfd: correct relocation handling for objcopy COFF -> ELF
While documented to not be reliable, it is still odd for objcopy to silently produce bad output when converting COFF/PE object files to ELF ones. The issue there is that relocation addends all are screwed up by subtracting the symbol's section offset. In the COFF/PE world, to my knowledge, section contents stores the addends alone, not the result of symbol value plus addend. Hence the compensation talked about in a comment ahead of the sole use site of CALC_ADDEND() may need to account for the VMA (which is always zero for object files anyway), but not for the symbol value. The coff-sh.c adjustment is based upon guessing that behavior there is the same. Note also how coff-aarch64.c short-circuits CALC_ADDEND() altogether, which may suggest that a much simpler macro might do for the COFF_WITH_PE case in the three arch-specific files touched here. For (at least) Arm/WinCE this actually results in more appropriate objdump output as well, as can be seen in the one testcase which has its expectations adjusted (the generated binary doesn't change).
Diffstat (limited to 'bfd/coffcode.h')
-rw-r--r--bfd/coffcode.h9
1 files changed, 8 insertions, 1 deletions
diff --git a/bfd/coffcode.h b/bfd/coffcode.h
index e3f4afd..2792703 100644
--- a/bfd/coffcode.h
+++ b/bfd/coffcode.h
@@ -5192,6 +5192,12 @@ SUBSUBSECTION
final-linked object. See @code{CALC_ADDEND}.
*/
+#ifdef COFF_WITH_PE
+#define COFF_PE_ADDEND_BIAS(ptr) 0 /* Symbol value not stored in raw data. */
+#else
+#define COFF_PE_ADDEND_BIAS(ptr) ((ptr)->value)
+#endif
+
#ifndef CALC_ADDEND
#define CALC_ADDEND(abfd, ptr, reloc, cache_ptr) \
{ \
@@ -5208,7 +5214,8 @@ SUBSUBSECTION
cache_ptr->addend = 0; \
else if (ptr && bfd_asymbol_bfd (ptr) == abfd \
&& ptr->section != NULL) \
- cache_ptr->addend = - (ptr->section->vma + ptr->value); \
+ cache_ptr->addend = - (ptr->section->vma \
+ + COFF_PE_ADDEND_BIAS (ptr)); \
else \
cache_ptr->addend = 0; \
}