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5eb4d7627a
We ought to detect when a data member is replaced by an anonymous data
member in a way that doesn't change the ABI in an incompatible way,
especially when that change is non equivocal.
For instance, consider this ABI-visible struct:
struct S
{
int a;
};
Now, consider that it's changed into:
struct S
{
union
{
int a;
char b;
};
};
Stricto sensu, the bit-layout of struct S doesn't change and so that
change isn't ABI-incompatible.
The current version of libabigail however flags that change as a
/potential/ issue and asks the user for further review. It appears
that this class of changes is frequent enough to be annoying,
especially in semi-automatic ABI compliance checking setups where we
want the least possible "false positives".
This patch detects that kind of change patterns where a data member is
replaced by an anonymous data member in a benign way, in terms of ABI.
So now let's look at a more complicated example where an ABI-visible
type looks like:
struct S
{
int a;
int b;
int c;
};
Now suppose that type was changed into:
struct S
{
union
{
int tag[3];
struct
{
int a;
int b;
int c;
};
};
};
The patch allows abidiff to recognise that kind of pattern, filter out
the detected change and report by default that the two binaries are
ABI compatible.
Here are the output that we'd get:
$ abidiff test-v0.o test-v1.o
Functions changes summary: 0 Removed, 0 Changed (1 filtered out), 0 Added function
Variables changes summary: 0 Removed, 0 Changed, 0 Added variable
When asked to show the detailed of the filtered out changes, we get:
$ abidiff --harmless test-v0.o test-v1.o
Functions changes summary: 0 Removed, 1 Changed, 0 Added function
Variables changes summary: 0 Removed, 0 Changed, 0 Added variable
1 function with some indirect sub-type change:
[C] 'function void foo(S*)' at test-v1.cc:18:1 has some indirect sub-type changes:
parameter 1 of type 'S*' has sub-type changes:
in pointed to type 'struct S' at test-v1.cc:1:1:
type size hasn't changed
data members 'S::a', 'S::b', 'S::c' were replaced by anonymous data member:
'union {int tag[3]; struct {int a; int b; int c;};}'
And using the leaf-node reporter, that would give:
$ abidiff --leaf-changes-only --harmless test-v0.o test-v1.o
Leaf changes summary: 1 artifact changed
Changed leaf types summary: 1 leaf type changed
Removed/Changed/Added functions summary: 0 Removed, 0 Changed, 0 Added function
Removed/Changed/Added variables summary: 0 Removed, 0 Changed, 0 Added variable
'struct S at test-v0.cc:1:1' changed:
type size hasn't changed
data members 'S::a', 'S::b', 'S::c' were replaced by anonymous data member:
'union {int tag[3]; struct {int a; int b; int c;};}'
* include/abg-comp-filter.h (has_data_member_replaced_by_anon_dm):
Declare new function.
* include/abg-comparison.h (changed_var_sptr)
(changed_var_sptrs_type): Declare new typedefs.
(HARMLESS_DATA_MEMBER_CHANGE_CATEGORY): Add a new enumerator to
the diff_category enum.
(EVERYTHING_CATEGORY): In the diff_category, adjust this
enumerator to OR the new HARMLESS_DATA_MEMBER_CHANGE_CATEGORY into
it.
(SUPPRESSED_CATEGORY, PRIVATE_TYPE_CATEGORY)
(SIZE_OR_OFFSET_CHANGE_CATEGORY, VIRTUAL_MEMBER_CHANGE_CATEGORY)
(CLASS_DECL_ONLY_DEF_CHANGE_CATEGORY)
(FN_PARM_TYPE_TOP_CV_CHANGE_CATEGORY)
(FN_RETURN_TYPE_CV_CHANGE_CATEGORY, VAR_TYPE_CV_CHANGE_CATEGORY)
(VOID_PTR_TO_PTR_CHANGE_CATEGORY)
(BENIGN_INFINITE_ARRAY_CHANGE_CATEGORY): Adjust the value of these
enumerators of the diff_category enum.
(class_or_union_diff::{data_members_replaced_by_adms,
ordered_data_members_replaced_by_adms}): Declare new member
functions.
* include/abg-fwd.h (var_decl_wptr): Declare new typedef.
(get_next_data_member, get_first_non_anonymous_data_member)
(find_data_member_from_anonymous_data_member)
(get_absolute_data_member_offset): Declare new functions.
* include/abg-ir.h (struct anonymous_dm_hash): Declare new type.
(anonymous_data_member_sptr_set_type): Declare new typedef.
(class decl_base): Befriend class class_or_union.
(class dm_context_rel): Pimpl-ify this class.
(dm_context_rel::{g,s}et_anonymous_data_member_types): Declare new
member functions.
(var_decl::get_anon_dm_reliable_name): Declare new member
function.
(class var_decl): Make get_absolute_data_member_offset,
get_absolute_data_member_offset be friends of this.
(class_or_union::maybe_fixup_members_of_anon_data_member): Declare
new protected member function.
* src/abg-comp-filter.cc (has_data_member_replaced_by_anon_dm):
Define new function.
(categorize_harmless_diff_node): Use the above.
* src/abg-comparison-priv.h
(class_or_union_diff::priv::{dms_replaced_by_adms_,
changed_var_sptrs_type dms_replaced_by_adms_ordered_}): Add new
data members.
(data_member_comp::compare_data_members): Factorize this out of ...
(data_member_comp::operator()(decl_base_sptr&, decl_base_sptr&)):
... this.
(data_member_comp::operator()(changed_var_sptr&,
changed_var_sptr&)): Add new member function.
(sort_changed_data_members): Declare ...
* src/abg-comparison.cc (sort_changed_data_members): ... new
function.
(get_default_harmless_categories_bitmap): Adjust to take the new
abigail::comparison::HARMLESS_DATA_MEMBER_CHANGE_CATEGORY into
account.
(operator<<(ostream& o, diff_category c)): Likewise.
(class_or_union_diff::ensure_lookup_tables_populated): Handle
Handle the insertion of anonymous data members to replace existing
data members.
(class_or_union_diff::{data_members_replaced_by_adms,
ordered_data_members_replaced_by_adms}): Define new accessors.
(suppression_categorization_visitor::visit_end): Propagate the
SUPPRESSION_CATEGORIZATION_VISITOR from changes to the type of the
data member if the data member doesn't have real local changes.
* src/abg-default-reporter.cc (default_reporter::report): Report
about anonymous data members that replace data members.
* src/abg-ir.cc (struct dm_context_rel::priv): Define new data
structure.
(dm_context_rel::{dm_context_rel, get_is_laid_out,
set_is_laid_out, get_offset_in_bits, set_offset_in_bits,
operator==, operator!=, get_anonymous_data_member,
set_anonymous_data_member}): Define the member functions here as
they are not inline anymore.
(class_or_union::maybe_fixup_members_of_anon_data_member): Define
new member function.
(class_or_union::add_data_member): Use it.
(get_first_non_anonymous_data_member, get_next_data_member)
(get_absolute_data_member_offset)
(find_data_member_from_anonymous_data_member): Define new
functions.
* src/abg-reporter-priv.h
(maybe_report_data_members_replaced_by_anon_dm): Declare ...
* src/abg-reporter-priv.cc
(maybe_report_data_members_replaced_by_anon_dm): ... new function.
* src/abg-leaf-reporter.cc (leaf_reporter::report): Report data
members replaced by anonymous data members.
* tests/data/test-diff-filter/test-PR25661-[1-6]-report-[1-4].txt: New
test reference outputs.
* tests/data/test-diff-filter/test-PR25661-[1-6]-v{0,1}.c: Test
source code files.
* tests/data/test-diff-filter/test-PR25661-[1-6]-v{0,1}.o: Test
binary input files.
* tests/data/Makefile.am: Add the new test files above to source
distribution.
* tests/test-diff-filter.cc (in_out_specs): Add the binary test
inputs above to this test harness.
* tests/data/test-diff-dwarf/test45-anon-dm-change-report-0.txt:
Adjust.
Signed-off-by: Dodji Seketeli <dodji@redhat.com>
|
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|---|---|---|
| .. | ||
| abg-comp-filter.h | ||
| abg-comparison.h | ||
| abg-config.h | ||
| abg-corpus.h | ||
| abg-cxx-compat.h | ||
| abg-diff-utils.h | ||
| abg-dwarf-reader.h | ||
| abg-fwd.h | ||
| abg-hash.h | ||
| abg-ini.h | ||
| abg-interned-str.h | ||
| abg-ir.h | ||
| abg-libxml-utils.h | ||
| abg-libzip-utils.h | ||
| abg-reader.h | ||
| abg-regex.h | ||
| abg-reporter.h | ||
| abg-sptr-utils.h | ||
| abg-suppression.h | ||
| abg-tools-utils.h | ||
| abg-traverse.h | ||
| abg-version.h.in | ||
| abg-viz-common.h | ||
| abg-viz-dot.h | ||
| abg-viz-svg.h | ||
| abg-workers.h | ||
| abg-writer.h | ||
| Makefile.am | ||