On Fri, Jun 7, 2024 at 8:29 AM Tom de Vries <tdevries@suse.de> wrote:

> After fixing test-case gdb.python/py-disasm.exp to recognize the arm nop:
> ...
>         nop     {0}
> ...
> we run into:
> ...
> disassemble test^M
> Dump of assembler code for function test:^M
>    0x004004d8 <+0>:     push    {r11}           @ (str r11, [sp, #-4]!)^M
>    0x004004dc <+4>:     add     r11, sp, #0^M
>    0x004004e0 <+8>:     nop     {0}^M
> => 0x004004e4 <+12>:    Python Exception <class 'ValueError'>: Buffer \
>   returned from read_memory is sized 0 instead of the expected 4^M
> ^M
> unknown disassembler error (error = -1)^M
> (gdb) FAIL: $exp: global_disassembler=ShowInfoRepr: disassemble test
> ...
>
> This is caused by this code in gdbpy_disassembler::read_memory_func:
> ...
>   gdbpy_ref<> result_obj (PyObject_CallMethod ((PyObject *) obj,
>                                               "read_memory",
>                                               "KL", len, offset));
> ...
> where len has type "unsigned int", and offset has type "LONGEST".
>
> Indeed L means "long long", but K means "unsigned long long".
>
> Fix this by using I instead, meaning "unsigned int".
>
> Tested on arm-linux.
>
> PR python/31845
> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31845
> ---
>  gdb/python/py-disasm.c                 | 2 +-
>  gdb/testsuite/gdb.python/py-disasm.exp | 2 +-
>  gdb/testsuite/gdb.python/py-disasm.py  | 2 +-
>  3 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/gdb/python/py-disasm.c b/gdb/python/py-disasm.c
> index 2d8ce44a065..a545ec8d3cb 100644
> --- a/gdb/python/py-disasm.c
> +++ b/gdb/python/py-disasm.c
> @@ -855,7 +855,7 @@ gdbpy_disassembler::read_memory_func (bfd_vma memaddr,
> gdb_byte *buff,
>       overridden by the user.  */
>    gdbpy_ref<> result_obj (PyObject_CallMethod ((PyObject *) obj,
>                                                "read_memory",
> -                                              "KL", len, offset));
> +                                              "IL", len, offset));
>
>    /* Handle any exceptions.  */
>    if (result_obj == nullptr)
> diff --git a/gdb/testsuite/gdb.python/py-disasm.exp
> b/gdb/testsuite/gdb.python/py-disasm.exp
> index 7c6f972a7e7..5d7d9221169 100644
> --- a/gdb/testsuite/gdb.python/py-disasm.exp
> +++ b/gdb/testsuite/gdb.python/py-disasm.exp
> @@ -65,7 +65,7 @@ proc py_remove_all_disassemblers {} {
>  #
>  # Each different disassembler tests some different feature of the
>  # Python disassembler API.
> -set nop "(nop|nop\t0)"
> +set nop "(nop|nop\t0|[string_to_regexp nop\t{0}])"
>  set unknown_error_pattern "unknown disassembler error \\(error = -1\\)"
>  set addr_pattern "\r\n=> ${curr_pc_pattern} <\[^>\]+>:\\s+"
>  set base_pattern "${addr_pattern}${nop}"
> diff --git a/gdb/testsuite/gdb.python/py-disasm.py
> b/gdb/testsuite/gdb.python/py-disasm.py
> index c09eae811ee..2741fdb6c19 100644
> --- a/gdb/testsuite/gdb.python/py-disasm.py
> +++ b/gdb/testsuite/gdb.python/py-disasm.py
> @@ -46,7 +46,7 @@ def check_building_disassemble_result():
>
>
>  def is_nop(s):
> -    return s == "nop" or s == "nop\t0"
> +    return s == "nop" or s == "nop\t0" or s == "nop\t{0}"
>
>
>  # Remove all currently registered disassemblers.
>
> base-commit: f9478936896ada7786e8d68622f6e6ff78b97b0d
> --
> 2.35.3
>
> Looks reasonable.
 Reviewed-By: Alexandra Petlanova Hajkova <ahajkova@redhat.com>