Re: [PATCH 2/4] Add Jeff Mahoney's py-crash patches.

[Jeff Mahoney <jeffm at suse dot com>]

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On 2/1/16 5:22 PM, Doug Evans wrote:
> On Sun, Jan 31, 2016 at 1:44 PM, Ales Novak <alnovak@suse.cz>
> wrote:
>> --- gdb/Makefile.in              |  12 ++ 
>> gdb/python/py-minsymbol.c    | 353
>> +++++++++++++++++++++++++++++++++++++ gdb/python/py-objfile.c
>> |  29 +++- gdb/python/py-section.c      | 401
>> +++++++++++++++++++++++++++++++++++++++++++ 
>> gdb/python/py-symbol.c       |  52 ++++-- 
>> gdb/python/python-internal.h |  14 ++ gdb/python/python.c
>> |   7 +- 7 files changed, 853 insertions(+), 15 deletions(-) 
>> create mode 100644 gdb/python/py-minsymbol.c create mode 100644
>> gdb/python/py-section.c
> 
> 
> Hi.

Hi Doug -

> Part of what this patch is doing is exporting bfd to python. E.g.,
> all the SEC_* constants.
> 
> As a rule we absolutely discourage people from using bfd outside
> of the the binutils+gdb source tree. Either this rule needs to
> change, or I don't think we can allow this patch. I'd be interested
> to hear what others in the community think.

That's unfortunate.  The Linux kernel uses ELF sections for a number
of purposes.  Most notably is the definition of per-cpu variables.
Without the ELF section, we can't resolve the addresses for the
variables.  So, from our perspective, it's a requirement.

> For myself, I would much rather export ELF separately (e.g., a
> separate python API one can use independent of any particular tool,
> including gdb), and then have gdb provide the necessary glue to use
> this API. [I can imagine some compromises being needed, at least
> for now; e.g., it'd be cumbersome to read in all ELF symbols
> twice. But fixing that is just an optimization.]

Ok, that's doable.  As it is, the section code mixes GDB and BFD
pretty heavily.  It shouldn't be too difficult to separate the two out
and push the section stuff into a new BFD python interface and
associate the objfiles with it.

- -Jeff

> 
>> ... +  if (PyModule_AddIntConstant (gdb_module, "SEC_NO_FLAGS",
>> SEC_NO_FLAGS) < 0 +      || PyModule_AddIntConstant (gdb_module,
>> "SEC_ALLOC", SEC_ALLOC) < 0 +      || PyModule_AddIntConstant
>> (gdb_module, "SEC_LOAD", SEC_LOAD) < 0 +      ||
>> PyModule_AddIntConstant (gdb_module, "SEC_RELOC", SEC_RELOC) < 0 
>> +      || PyModule_AddIntConstant (gdb_module, "SEC_READONLY",
>> SEC_READONLY) < 0 +      || PyModule_AddIntConstant (gdb_module,
>> "SEC_CODE", SEC_CODE) < 0 +      || PyModule_AddIntConstant
>> (gdb_module, "SEC_DATA", SEC_DATA) < 0 +      ||
>> PyModule_AddIntConstant (gdb_module, "SEC_ROM", SEC_ROM) < 0 +
>> || PyModule_AddIntConstant (gdb_module, "SEC_CONSTRUCTOR", +
>> SEC_CONSTRUCTOR) < 0 +      || PyModule_AddIntConstant
>> (gdb_module, "SEC_HAS_CONTENTS", +
>> SEC_HAS_CONTENTS) < 0 +      || PyModule_AddIntConstant
>> (gdb_module, "SEC_NEVER_LOAD", +
>> SEC_NEVER_LOAD) < 0 +      || PyModule_AddIntConstant
>> (gdb_module, "SEC_THREAD_LOCAL", +
>> SEC_THREAD_LOCAL) < 0 +      || PyModule_AddIntConstant
>> (gdb_module, "SEC_HAS_GOT_REF", +
>> SEC_HAS_GOT_REF) < 0 +      || PyModule_AddIntConstant
>> (gdb_module, "SEC_IS_COMMON", +
>> SEC_IS_COMMON) < 0 +      || PyModule_AddIntConstant (gdb_module,
>> "SEC_DEBUGGING", +                                 SEC_DEBUGGING)
>> < 0 +      || PyModule_AddIntConstant (gdb_module,
>> "SEC_IN_MEMORY", +                                 SEC_IN_MEMORY)
>> < 0 +      || PyModule_AddIntConstant (gdb_module, "SEC_EXCLUDE",
>> SEC_EXCLUDE) < 0 +      || PyModule_AddIntConstant (gdb_module,
>> "SEC_SORT_ENTRIES", +
>> SEC_SORT_ENTRIES) < 0 +      || PyModule_AddIntConstant
>> (gdb_module, "SEC_LINK_ONCE", +
>> SEC_LINK_ONCE) < 0 +      || PyModule_AddIntConstant (gdb_module,
>> "SEC_LINK_DUPLICATES", +
>> SEC_LINK_DUPLICATES) < 0 +      || PyModule_AddIntConstant
>> (gdb_module, "SEC_LINK_DUPLICATES_DISCARD", +
>> SEC_LINK_DUPLICATES_DISCARD) < 0 +      ||
>> PyModule_AddIntConstant (gdb_module,
>> "SEC_LINK_DUPLICATES_ONE_ONLY", +
>> SEC_LINK_DUPLICATES_ONE_ONLY) < 0 +      ||
>> PyModule_AddIntConstant (gdb_module,
>> "SEC_LINK_DUPLICATES_SAME_SIZE", +
>> SEC_LINK_DUPLICATES_SAME_SIZE) < 0 +      ||
>> PyModule_AddIntConstant (gdb_module, "SEC_LINKER_CREATED", +
>> SEC_LINKER_CREATED) < 0 +      || PyModule_AddIntConstant
>> (gdb_module, "SEC_KEEP", SEC_KEEP) < 0 +      ||
>> PyModule_AddIntConstant (gdb_module, "SEC_SMALL_DATA", +
>> SEC_SMALL_DATA) < 0 +      || PyModule_AddIntConstant
>> (gdb_module, "SEC_MERGE", SEC_MERGE) < 0 +      ||
>> PyModule_AddIntConstant (gdb_module, "SEC_STRNGS", SEC_STRINGS) <
>> 0 +      || PyModule_AddIntConstant (gdb_module, "SEC_GROUP",
>> SEC_GROUP) < 0 +      || PyModule_AddIntConstant (gdb_module,
>> "SEC_COFF_SHARED_LIBRARY", +
>> SEC_COFF_SHARED_LIBRARY) < 0 +      || PyModule_AddIntConstant
>> (gdb_module, "SEC_ELF_REVERSE_COPY", +
>> SEC_ELF_REVERSE_COPY) < 0 +      || PyModule_AddIntConstant
>> (gdb_module, "SEC_COFF_SHARED", +
>> SEC_COFF_SHARED) < 0 +      || PyModule_AddIntConstant
>> (gdb_module, "SEC_COFF_NOREAD", +
>> SEC_COFF_NOREAD) < 0) +    return -1; ...
> 


- -- 
Jeff Mahoney
SUSE Labs
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