[all-commits] [llvm/llvm-project] e5c19b: [BOLT] Skip function instead of aborting on jump t...

[nitro via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: e5c19b0ebc54206348273fc2f7cf67cb195908ed
      https://github.com/llvm/llvm-project/commit/e5c19b0ebc54206348273fc2f7cf67cb195908ed
  Author: nitro <nitro123 at outlook.com>
  Date:   2026-07-15 (Wed, 15 Jul 2026)

  Changed paths:
    M bolt/lib/Core/BinaryContext.cpp
    A bolt/test/X86/jump-table-failed-reanalysis.s

  Log Message:
  -----------
  [BOLT] Skip function instead of aborting on jump table analysis failure (#206742)

`analyzeJumpTable()` runs twice on a candidate jump table: once from
`analyzeMemoryAt` while the referencing function is being disassembled,
and
again from `populateJumpTables()` after disassembly. The second run is
stricter,
because the check that an entry points at an instruction
(`getInstructionAtOffset`) only fires once the target function reaches
the
`Disassembled` state. A table can therefore be accepted the first time
and
rejected the second -- for instance when an entry lands at an address
with no
instruction (a symbol whose declared size is larger than its
disassembled
extent). `populateJumpTables()` reached `llvm_unreachable("jump table
heuristic
failure")` and aborted in that case.

Handle it the way BOLT already handles indirect branches it can't
analyze: drop
the table and skip the owning function(s) via `addFragmentsToSkip()`.
The
`JumpTable` is deliberately left in the maps so it is still freed by
`~BinaryContext` (an earlier attempt at this, 52cd00ca, was reverted in
468d4f6d
because it erased the table without deallocating it).

New test `jump-table-failed-reanalysis.s` builds such a table; before
this change
BOLT aborts, after it the function is skipped and the rest of the binary
is
processed normally.



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