Re: [PATCH 2/2] Introduce Python testcases to check DWARF output

[David Malcolm <dmalcolm at redhat dot com>]

On Wed, 2017-07-26 at 18:00 +0200, Pierre-Marie de Rodat wrote:
[...]
> diff --git a/gcc/testsuite/python/dwarfutils/__init__.py
> b/gcc/testsuite/python/dwarfutils/__init__.py
> new file mode 100644
> index 00000000000..246fbbd15be
> --- /dev/null
> +++ b/gcc/testsuite/python/dwarfutils/__init__.py
[...]
> +def parse_dwarf(object_file=None, single_cu=True):
> +    """
> +    Fetch and decode DWARF compilation units in `object_file`.
> +
> +    If `single_cu` is True, make sure there is exactly one
> compilation unit and

"is True" -> "is true"

[...]

> --- /dev/null
> +++ b/gcc/testsuite/python/dwarfutils/data.py

> +
> +    def get_attr(self, name, single=True, or_error=True):
> +        """Look for an attribute in this DIE.
> +
> +        :param str|int name: Attribute name, or number if name is
> unknown.
> +        :param bool single: If true, this will raise a KeyError for
> +            zero/multiple matches and return an Attribute instance
> when found.
> +            Otherwise, return a potentially empty list of
> attributes.
> +        :param bool or_error: When True, if `single` is True and no
> attribute

"True" -> "true" in two places

[...]

> +    def find(self, predicate=None, tag=None, name=None,
> recursive=True,
> +             single=True):
> +        """Look for a DIE that satisfies the given expectations.
> +
> +        :param None|(DIE) -> bool predicate: If provided, function
> that filters
> +            out DIEs when it returns False.
> +        :param str|int|None tag: If provided, filter out DIEs whose
> tag does
> +            not match.
> +        :param str|None name: If provided, filter out DIEs whose
> name (see
> +            the `name` property) does not match.
> +        :param bool recursive: If True, perform the search
> recursively in
> +            self's children.
> +        :param bool single: If True, look for a single DIE and raise
> a

"True" -> "true", I suppose

[...]

> +class MatchResult(object):
> +    """Holder for the result of a DIE tree pattern match."""
> +
> +    def __init__(self):
> +        self.dict = {}
> +
> +        self.mismatch_reason = None
> +        """
> +        If left to None, the match succeded. Otherwise, must be set


"succeded" -> "succeeded"

> +
> +    def capture(self, name):
> +        """Return what has been captured by the `name` capture.
> +
> +        This is valid iff the match succeded.

here again.

[...]


> diff --git a/gcc/testsuite/python/dwarfutils/helpers.py
> b/gcc/testsuite/python/dwarfutils/helpers.py
> new file mode 100644
> index 00000000000..f5e77896ae6
> --- /dev/null
> +++ b/gcc/testsuite/python/dwarfutils/helpers.py
> @@ -0,0 +1,11 @@
> +import sys
> +
> +
> +def as_ascii(str_or_byte):
> +    """
> +    Python 2/3 compatibility helper.
> +
> +    In Python 2, just return the input. In Python 3, decode the
> input as ASCII.
> +    """
> +    return (str_or_byte if sys.version_info.major < 3 else
> +            str_or_byte.decode('ascii'))

Aha!  Python 2 and Python 3.


Presumably this all runs with LANG=C so that there's no danger of any
non-ASCII bytes?  (bytes.decode('ascii' will raise a UnicodeDecodeError
if any byte >=128).


> diff --git a/gcc/testsuite/python/dwarfutils/objdump.py
> b/gcc/testsuite/python/dwarfutils/objdump.py
> new file mode 100644
> index 00000000000..52cfc06c03b
> --- /dev/null
> +++ b/gcc/testsuite/python/dwarfutils/objdump.py

[...]

There's a fair amount of non-trivial parsing going on here.
I wonder if it would be helpful to add a "unittest" suite for the
parsing?
(e.g. to have some precanned fragments of objdump output as strings,
and to verify that they're parsed as expected).

Note that I'm not a reviewer for the testsuite, so this is just a
suggestion.

Hope this is constructive
Dave