this was one of the main instances of ugly code duplication: all archs
use basically the same types of relocations, but roughly equivalent
logic was duplicated for each arch to account for the different naming
and numbering of relocation types and variation in whether REL or RELA
records are used.
as an added bonus, both REL and RELA are now supported on all archs,
regardless of which is used by the standard toolchain.
the following issues are fixed:
- R_SH_REL32 was adding the load address of the module being relocated
to the result. this seems to have been a mistake in the original
port, since it does not match other dynamic linker implementations
and since adding a difference between two addresses (the symbol
value and the relocation address) to a load address does not make
sense.
- R_SH_TLS_DTPMOD32 was wrongly accepting an inline addend (i.e. using
+= rather than = on *reloc_addr) which makes no sense; addition is
not an operation that's defined on module ids.
- R_SH_TLS_DTPOFF32 and R_SH_TLS_TPOFF32 were wrongly using inline
addends rather than the RELA-provided addends.
in addition, handling of R_SH_GLOB_DAT, R_SH_JMP_SLOT, and R_SH_DIR32
are merged to all honor the addend. the first two should not need it
for correct usage generated by toolchains, but other dynamic linkers
allow addends here, and it simplifies the code anyway.
these issues were spotted while reviewing the code for the purpose of
refactoring this part of the dynamic linker. no testing was performed.
the immediate motivation is supporting TLSDESC relocations which
require allocation and thus may fail (unless we pre-allocate), but
this mechanism should also be used for throwing an error on
unsupported or invalid relocation types, and perhaps in certain cases,
for reporting when a relocation is not satisfiable.
linux, gcc, etc. all use "sh" as the name for the superh arch. there
was already some inconsistency internally in musl: the dynamic linker
was searching for "ld-musl-sh.path" as its path file despite its own
name being "ld-musl-superh.so.1". there was some sentiment in both
directions as to how to resolve the inconsistency, but overall "sh"
was favored.
Rich Felker
Bobby Bingham