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btfdiff: Use --show_private_classes with DWARF 

In DWARF we have the information if a struct/class is defined only
inside another struct/class or in a function, and then we consider those
to be 'private classes', requiring the use of --show_private_classes to
see those when asking for all structs.

That is not the case with BTF, that doesn't have that info and thus
shows all structs, private or not.

So, to compare the outputs in btfdiff we need to ask for
--show_private_classes when printing from DWARF.

With the Linux kernel vmlinux file the only private structure noticed
when not using this option, i.e. the only private class, as 'struct
sun_disklabel', defined in the block/partitions/sun.c file, inside the
'sun_partition' function.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo 2019-02-19 11:04:44 -03:00
parent e6c59bd11d
commit 88028b5d0c
1 changed files with 4 additions and 1 deletions
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@ -2,6 +2,9 @@
# Copyright © 2019 Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>
# Use pahole to produce output from BTF and from DWARF, then do a diff
# Use --flat_arrays with DWARF as BTF, like CTF, flattens arrays.
# Use --show_private_classes as BTF shows all structs, while pahole knows
# if some struct is defined only inside another struct/class or in a function,
# this information is not available when loading from BTF.
if [ $# -eq 0 ] ; then
echo "Usage: btfdiff <filename_with_BTF_and_DWARF_info>"
@ -12,7 +15,7 @@ file=$1
btf_output=$(mktemp /tmp/btfdiff.btf.XXXXXX)
dwarf_output=$(mktemp /tmp/btfdiff.dwarf.XXXXXX)
pahole -F dwarf --flat_arrays $file > $dwarf_output
pahole -F dwarf --flat_arrays --show_private_classes $file > $dwarf_output
pahole -F btf $file > $btf_output
diff -up $dwarf_output $btf_output