clang++18: ERROR: print .debug_names section failed: DW_DLE_READ_LITTLEENDIAN_ERROR Read would end past the end of section.

[PolarNettles]

With the fix for https://github.com/davea42/libdwarf-code/issues/260 I am now hitting this error. It looks like it happens when the last entry of .debug_names specifies a DW_IDX_parent.

ubu@xxx:~/libdwarf-0.11.0/src/bin/dwarfdump$ llvm-dwarfdump --debug-names cpp_test.o
cpp_test.o:     file format elf64-x86-64

.debug_names contents:
Name Index @ 0x0 {
...
  Bucket 8 [
    Name 9 {
      Hash: 0x7C9400EA
      String: 0x000000ef "afoo"
      Entry @ 0x138 {
        Abbrev: 0x1738
        Tag: DW_TAG_subprogram
        DW_IDX_die_offset: 0x00000071
        DW_IDX_parent: 0x0000002a
      }
    }
  ]
}

Reproduction steps:

ubu@xxx:~/libdwarf-0.11.0/src/bin/dwarfdump$ ./dwarfdump --print-debug-names cpp_test.o
...
./dwarfdump ERROR:  print .debug_names section failed:  DW_DLE_READ_LITTLEENDIAN_ERROR Read would end past the end of section. Attempting to continue.

cpp_test.zip

[davea42]

Reading DW_FORM_ref4 from a .debug_names table we were double-counting the 4 bytes read. oops. Running a full regression test now. Also, for a debug_names FORM_ref1 we were not checking for past-end.. Fixed.

[davea42]

I am updating the dwarfdump --print-debug-names format today so it looks better. Nothing changing in the library. Regression tests have run just fine, though I am rerunning now.

[davea42]

The feature, I learned today from the person who implemented it in clang, is to distinguish two cases for the code reading the .debug_names section:

1, Absence of DW_IDX_parent means the producer did not generate a parent.

2. DW_IDX_parent with DW_FORM_flag_present means means the parent is not indexed though it was generated.

[davea42]

dwarfdump now reports this. I think this can be closed.