[LLVMdev] Assertions in RuntimeDyldELF in ExecutionEngine/MCJIT tests

[Alexey Samsonov]

Hi!

I'm trying to run LLVM test suite under AddressSanitizer and get test
failures in:
    LLVM :: ExecutionEngine/MCJIT/simpletest-remote.ll
    LLVM :: ExecutionEngine/MCJIT/test-data-align-remote.ll
    LLVM :: ExecutionEngine/MCJIT/test-fp-no-external-funcs-remote.ll
    LLVM :: ExecutionEngine/MCJIT/test-global-init-nonzero-remote.ll

All of them fail with assertion:
lli:
/usr/local/google/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp:230:
void llvm::RuntimeDyldELF::resolveX86_64Relocation(const llvm::SectionEntry
&, uint64_t, uint64_t, uint32_t, int64_t): Assertion `RealOffset <=
(2147483647) && RealOffset >= (-2147483647-1)' failed.

The reason is that AddressSanitizer replaces system malloc with its own
allocator, which
allocates memory at "unusual" parts of heap and the difference between
pointers can be significant
(and doesn't fit in 32 bytes).

I add debug output to calculation of RealOffset in resolveX86_64Relocation:

    uint64_t  FinalAddress = Section.LoadAddress + Offset;
    int64_t RealOffset = *Placeholder + Value + Addend - FinalAddress;
    fprintf(stderr, "%x + %lx + %lx - %lx = %lx\n",
            *Placeholder, Value, Addend, FinalAddress, RealOffset);
    assert(RealOffset <= INT32_MAX && RealOffset >= INT32_MIN);

This is what I get for system malloc:

0 + 7fec9867a000 + 0 - 7fec9867a040 = ffffffffffffffc0

This is what I get for ASan allocator (which results in assert failure):

0 + 600c0000a8a0 + 0 - 6018000090a0 = fffffff400001800


--
Alexey Samsonov, MSK
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