Dead code elimination in ELF uses separate ELF sections for every
functions or data items that may be garbage collected. This can end up
being more than 32,633 sections which, when the ELF internal and
relocation sections are added in, can exceed the legacy ELF maximum of
65,279 sections.
Newer versions of the ELF specification has added support for much
larger number of sections by putting a place holder value (usually
SHN_XINDEX == 0xffff, but 0 in some cases) into fields where the
section index is a 16-bit value, and storing the full value in a
diffent place: the program header uses entries in section header 0,
the symbol table uses an auxiliary segment with the additional
indicies; the section header did not need it as the sh_link field is
already 32 (or 64) bits long.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Use a hash table to look up sections by name, and an RAA to look up
sections by index; thus remove O(n) searches. This becomes important
since ELF uses sections for dead code elimination.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
