[PATCH] D130395: [DWP][DWARF] Detect and error on debug info offset overflow

[Alexander Yermolovich via Phabricator via llvm-commits]

ayermolo added a comment.

In D130395#3675026 <https://reviews.llvm.org/D130395#3675026>, @dblaikie wrote:

> Could /maybe/ test this with an assembly test, but it'd still have to generate something like a 4GB file... which probably isn't a great idea. Maybe have a test that's checked in and can be run manually, but I guess no one would ever know it was there/know to run it.
>
> But could you copy/paste some terminal execution that shows this failing/erroring correctly?

Yeah I wasn't sure how to test it. Checking in 4GB test seemed excessive.

Base case:

  [~/local/bzip2_DF] ~/local/llvm-build-upstream-release/bin/llvm-dwp -e bzip2 -o bzip2.dwp
  [~/local/bzip2_DF] ~/local/llvm-build-upstream-release/bin/llvm-readelf --sections bzip2.dwp
  There are 10 section headers, starting at offset 0x14ad8:
  
  Section Headers:
    [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
    [ 0]                   NULL            0000000000000000 000000 000000 00      0   0  0
    [ 1] .strtab           STRTAB          0000000000000000 014a40 000091 00      0   0  1
    [ 2] .debug_loclists.dwo PROGBITS      0000000000000000 000040 009a92 00   E  0   0  1
    [ 3] .debug_abbrev.dwo PROGBITS        0000000000000000 009ad2 0010cb 00   E  0   0  1
    [ 4] .debug_rnglists.dwo PROGBITS      0000000000000000 00ab9d 0004e4 00   E  0   0  1
    [ 5] .debug_str.dwo    PROGBITS        0000000000000000 00b081 001833 01 MSE  0   0  1
    [ 6] .debug_str_offsets.dwo PROGBITS   0000000000000000 00c8b4 0010fc 00   E  0   0  1
    [ 7] .debug_info.dwo   PROGBITS        0000000000000000 00d9b0 006e50 00   E  0   0  1
    [ 8] .debug_cu_index   PROGBITS        0000000000000000 014800 000224 00      0   0  1
    [ 9] .symtab           SYMTAB          0000000000000000 014a28 000018 18      1   1  8
  Key to Flags:
    W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
    L (link order), O (extra OS processing required), G (group), T (TLS),
    C (compressed), x (unknown), o (OS specific), E (exclude),
    R (retain), l (large), p (processor specific)

Error case:

> [~/local/ErrorCase] ~/local/llvm-build-upstream-release/bin/llvm-dwp -e error_binary -o error_binary.dwp
> error: debug information section offset is greater than 4GB

Regarding our discussion https://discourse.llvm.org/t/dwarf-dwp-4gb-limit/63902. Basically nothing can be done at this point, beyond waiting for DWARF6 spec?

I can add error for string (different diff), but I don't have a test case that will trigger it.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D130395/new/

https://reviews.llvm.org/D130395