[PATCH] D49383: [cfi-verify] Support cross-DSO by treating certain calls as traps.

[Peter Collingbourne via Phabricator via llvm-commits]

pcc added a comment.

I agree with eugenis that the PLT symbolization should live in lib/Object. That would also help us implement PLT symbolization in llvm-objdump. I was imagining that there would be a function that would take an object file and return a list of (PLT entry address, symbol) pairs. That would seem to be sufficient for llvm-objdump as well as for this code.

I was discussing PLT symbolization offline with eugenis and did a little more investigation. It turns out that it shouldn't be that hard to symbolize the PLT, at least not on aarch64. All of bfd/gold/lld start their PLT entries with a straightforward ADRP/LDR sequence, which you can pretty straighforwardly map onto a GOT entry and then onto a symbol.



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Comment at: tools/llvm-cfi-verify/lib/FileAnalysis.cpp:539
+  TrapOnFailFunctions.insert("__cfi_slowpath");
+  TrapOnFailFunctions.insert("abort");
+  TrapOnFailFunctions.insert("__cfi_slowpath at plt");
----------------
Where does `abort` come from? In the diagnostic mode the failure path will end up calling `__ubsan_handle_cfi_check_fail` or `__ubsan_handle_cfi_check_fail_abort`.


https://reviews.llvm.org/D49383