<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/61949>61949</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [debuginfo-analyzer] VLAs cause debuginfo-analyzer to crash
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            debuginfo
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
            CarlosAlbertoEnciso
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          jmorse
      </td>
    </tr>
</table>

<pre>
    llvm-debuginfo-analyzer does not expect to see array variables where the size is non-constant, for example in this sample:

    void ext(int *, int);

    int foo(int bar) {
      int array[bar];
      ext(array, bar);
 return array[4];
    }

We get this DWARF:

    0x0000007a: DW_TAG_array_type
                    DW_AT_type      (0x00000072 "int")

    0x0000007f:     DW_TAG_subrange_type
 DW_AT_type    (0x00000089 "__ARRAY_SIZE_TYPE__")
 DW_AT_count   (0x0000003f)

    0x00000088:     NULL

Where the DW_AT_count is a reference to a DW_TAG_variable in the relevant subprogram. However, llvm-debuginfo-analyzer interprets everything that's a DW_AT_count as being an unsigned constant, and crashes. This is fairly simple to fix the crash for; whether there's a way of representing a variable-length array in the logical view of the debuginfo is a question I don't know the answer to. Tested with 77308dd400a1bc . Relevant bit of stack trace:

     #5 0x00007f9f90af9859 abort /build/glibc-SzIz7B/glibc-2.31/stdlib/abort.c:81:7 
     #6 0x0000000001559b73 llvm::logicalview::LVELFReader::processOneAttribute(llvm::DWARFDie const&, unsigned long*, llvm::DWARFAbbreviationDeclaration::AttributeSpec const&)
 #7 0x000000000155ae51 llvm::logicalview::LVELFReader::processOneDie(llvm::DWARFDie const&, llvm::logicalview::LVScope*, llvm::DWARFDie&) 
     #8 0x000000000155bac9 llvm::logicalview::LVELFReader::traverseDieAndChildren(llvm::DWARFDie&, llvm::logicalview::LVScope*, llvm::DWARFDie&) 
     #9 0x000000000155bb41 llvm::logicalview::LVELFReader::traverseDieAndChildren(llvm::DWARFDie&, llvm::logicalview::LVScope*, llvm::DWARFDie&) 
    #10 0x000000000155bb41 llvm::logicalview::LVELFReader::traverseDieAndChildren(llvm::DWARFDie&, llvm::logicalview::LVScope*, llvm::DWARFDie&) 
    #11 0x000000000155d440 llvm::logicalview::LVELFReader::createScopes() 
    #12 0x00000000014bf87d llvm::logicalview::LVReader::doLoad() 
    #13 0x00000000015014f8 llvm::logicalview::LVReaderHandler::createReader(llvm::StringRef, std::vector<std::unique_ptr<llvm::logicalview::LVReader, std::default_delete<llvm::logicalview::LVReader>>, std::allocator <std::unique_ptr<llvm::logicalview::LVReader, std::default_delete<llvm::logicalview::LVReader>>>>&, llvm::PointerUnion<llvm::object::ObjectFile*, llvm::pdb::PDBFile*>&, llvm::StringRef, llvm::StringRef)
</pre>
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