fablevoid 1541244b78 fix(relinker): treat jump table targets as branch targets when moving instructions ...

The AMD-only converter moves the instructions next to a short AMD-only
instruction into its stub, and refuses to move one that a branch
enters. It knew only direct jump and call targets, so a switch case
entered through a jump table could land inside the jump written over
the moved instructions.

The converter now also reads relative jump tables: a RIP-relative LEA
whose address lies in a loaded segment starts a table of 32-bit
offsets from that address, read while each target starts an
instruction of the segment being converted. To read them, Convert
takes the program headers and converts their executable load
segments; the relinker passes all headers, and
ElfReader::ReadCodeSegments, now unused, is removed.

The converter test builds a dispatch through such a table whose second
case enters the instruction after a 4-byte 256-bit store, and checks
that the store takes the instruction before it instead. It also checks
that reading stops at an entry that does not start an instruction,
that only a LEA forms a table address, that tables are read only
inside loaded segments, that only executable load segments are
converted, and that a segment past the end of the file fails the
conversion.

PPSA12544: one 256-bit store in Il2cppUserAssemblies moved the
instruction after it, which is case 1 of a switch; it now goes through
an island. The other relinked files are unchanged.

AI-assisted: yes

2026-10-12 13:06:23 +00:00

..

codegen

fix(relinker): treat jump table targets as branch targets when moving instructions

2026-10-12 13:06:23 +00:00