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When the DWARF reader encounters a function DIE 'f' that has a DW_AT_specification that points to a member function, the current implementation creates a function IR for the member function. The problem is that the member function has no ELF symbol associated to it. The ELF symbol is associated to 'f', not to the member function. The DWARF reader then wrongly drops the member function on the floor because it has no ELF symbol function associated. So that member function specification never gets its concrete function represented in the IR. This patch fixes the issue by detecting that the member function is the "specification" for 'f' and that the ELF symbol associated to it might not be there. In that case, if the ELF symbol is on the 'f' DIE itself, we get it from there. The patch makes more member functions to be represented so it uncovers a latent issue which is explained below. Today, some compilers can emit redundant DWARF constructs like "const reference" or "const void". A reference is always const so the const is superfluous. A similar thing can be said about "const void". maybe_strip_qualification detects those constructs and rewrites the IR into a "no-op qualified reference", or a "no-op qualified void". The no-op was needed in the previous incarnations of the DWARF reader because it was expecting a 'qualified type' IR to be associated to a qualified type DIE. Note, however, that that expectation has been generally relaxed since then. The problem is that the comparison engine, when building the diff IR needs to strip those no-op qualified types off, to avoid having spurious change diagnostics. That stripping introduces some challenges because the tree is more or less un-mutable at that point (after type canonicalization) so the stripping can only be partial. This patch removes the no-op qualified types altogether, rather than trying harder to handle them down the line. In other words, a const reference is now represented as a reference and a const void as a void. This makes things much simpler. The problem however is that the in-memory IR (and thus the emitted ABIXML) doesn't have any no-op qualified type anymore. So comparing an old ABIXML that contains those no-op qualified types against its origin ELF corpus can yield some spurious diagnostics. To fix it, one needs to re-generate the ABIXML file. This patch bumps the ABIXML version to 2.1 and introduces a new ABIXML-FORMAT-VERSIONS file that documents the format changes. * ABIXML-FORMAT-VERSIONS: New file that documents the version changes of the ABIXML-FORMAT-VERSIONS. * include/abg-fwd.h (look_through_no_op_qualified_type): Remove this function declaration. (strip_useless_const_qualification): Declare new function declaration. * src/abg-comparison.cc (compute_diff_for_types): Avoid stripping off no-op-qualified types as these beasts don't exist anymore. (redundancy_marking_visitor::visit_end): Allow a variable which type has local changes to be considered redundant if its type is itself redundant. * src/abg-config.cc (config::config): Bump the abixml version from 2.0 to 2.1. * src/abg-dwarf-reader.cc (maybe_strip_qualification): Factorize out the new strip_useless_const_qualification function from here. (build_or_get_fn_decl_if_not_suppressed): If the function is created but doesn't have an ELF symbol associated to it, then update it so that the ELF symbol can be associated. Otherwise, potential_member_fn_should_be_dropped might later drop that function on the floor because it doesn't have any ELF symbol associated. * src/abg-ir.cc (strip_useless_const_qualification): Define this, which is has been factorized out of maybe_strip_qualification. (look_through_no_op_qualified_type): Remove this definition. (equals): In the overload for reference_type_def, do not peel typedefs off from the reference before comparison. This is now useless as the comparison infrastructure got a lot better. In the overload for references, stop using look_through_no_op_qualified_type as this function doesn't exist anymore. * src/abg-tools-utils.cc (abidiff_status_has_error): Detect when there is a usage error as well. * tests/data/test-types-stability/PR28450-libepetra.so.13.0: Add new testing binary to the repository. * tests/data/Makefile.am: Add the new testing binary above to source distribution. * tests/test-types-stability.cc (elf_paths): Add the new test to this test harness. * tests/test-diff-dwarf-abixml.cc (main): Add better error messages. * tests/data/test-abidiff-exit/test-member-size-report0.txt: Adjust. * tests/data/test-annotate/libtest23.so.abi: Likewise. * tests/data/test-annotate/libtest24-drop-fns-2.so.abi: Likewise. * tests/data/test-annotate/libtest24-drop-fns.so.abi: Likewise. * tests/data/test-annotate/test-anonymous-members-0.o.abi: Likewise. * tests/data/test-annotate/test0.abi: Likewise. * tests/data/test-annotate/test1.abi: Likewise. * tests/data/test-annotate/test13-pr18894.so.abi: Likewise. * tests/data/test-annotate/test14-pr18893.so.abi: Likewise. * tests/data/test-annotate/test15-pr18892.so.abi: Likewise. * tests/data/test-annotate/test17-pr19027.so.abi: Likewise. * tests/data/test-annotate/test18-pr19037-libvtkRenderingLIC-6.1.so.abi: Likewise. * tests/data/test-annotate/test19-pr19023-libtcmalloc_and_profiler.so.abi: Likewise. * tests/data/test-annotate/test20-pr19025-libvtkParallelCore-6.1.so.abi: Likewise. * tests/data/test-annotate/test6.so.abi: Likewise. * tests/data/test-annotate/test7.so.abi: Likewise. * tests/data/test-annotate/test8-qualified-this-pointer.so.abi: Likewise. * tests/data/test-diff-dwarf-abixml/test0-pr19026-libvtkIOSQL-6.1.so.1.abi: Likewise. * tests/data/test-diff-dwarf/test0-report.txt: Likewise. * tests/data/test-diff-dwarf/test28-vtable-changes-report-0.txt: Likewise. * tests/data/test-diff-dwarf/test42-PR21296-clanggcc-report0.txt: Likewise. * tests/data/test-diff-filter/test0-report.txt: Likewise. * tests/data/test-diff-filter/test01-report.txt: Likewise. * tests/data/test-diff-filter/test10-report.txt: Likewise. * tests/data/test-diff-filter/test30-pr18904-rvalueref-report0.txt: Likewise. * tests/data/test-diff-filter/test30-pr18904-rvalueref-report1.txt: Likewise. * tests/data/test-diff-filter/test30-pr18904-rvalueref-report2.txt: Likewise. * tests/data/test-diff-filter/test31-pr18535-libstdc++-report-0.txt: Likewise. * tests/data/test-diff-filter/test31-pr18535-libstdc++-report-1.txt: Likewise. * tests/data/test-diff-filter/test35-pr18754-no-added-syms-report-0.txt: Likewise. * tests/data/test-diff-filter/test35-pr18754-no-added-syms-report-1.txt: Likewise. * tests/data/test-diff-filter/test41-report-0.txt: Likewise. * tests/data/test-diff-filter/test9-report.txt: Likewise. * tests/data/test-diff-pkg/libsigc++-2.0-0c2a_2.4.0-1_amd64--libsigc++-2.0-0v5_2.4.1-1ubuntu2_amd64-report-0.txt: Likewise. * tests/data/test-diff-pkg/tbb-4.1-9.20130314.fc22.x86_64--tbb-4.3-3.20141204.fc23.x86_64-report-0.txt: Likewise. * tests/data/test-diff-pkg/tbb-4.1-9.20130314.fc22.x86_64--tbb-4.3-3.20141204.fc23.x86_64-report-1.txt: Likewise. * tests/data/test-diff-suppr/test24-soname-report-1.txt: Likewise. * tests/data/test-diff-suppr/test24-soname-report-10.txt: Likewise. * tests/data/test-diff-suppr/test24-soname-report-12.txt: Likewise. * tests/data/test-diff-suppr/test24-soname-report-14.txt: Likewise. * tests/data/test-diff-suppr/test24-soname-report-16.txt: Likewise. * tests/data/test-diff-suppr/test24-soname-report-4.txt: Likewise. * tests/data/test-diff-suppr/test31-report-1.txt: Likewise. * tests/data/test-read-dwarf/PR22015-libboost_iostreams.so.abi: Likewise. * tests/data/test-read-dwarf/PR22122-libftdc.so.abi: Likewise. * tests/data/test-read-dwarf/libtest23.so.abi: Likewise. * tests/data/test-read-dwarf/libtest24-drop-fns-2.so.abi: Likewise. * tests/data/test-read-dwarf/libtest24-drop-fns.so.abi: Likewise. * tests/data/test-read-dwarf/test-libaaudio.so.abi: Likewise. * tests/data/test-read-dwarf/test-libandroid.so.abi: Likewise. * tests/data/test-read-dwarf/test0.abi: Likewise. * tests/data/test-read-dwarf/test0.hash.abi: Likewise. * tests/data/test-read-dwarf/test1.abi: Likewise. * tests/data/test-read-dwarf/test1.hash.abi: Likewise. * tests/data/test-read-dwarf/test10-pr18818-gcc.so.abi: Likewise. * tests/data/test-read-dwarf/test11-pr18828.so.abi: Likewise. * tests/data/test-read-dwarf/test12-pr18844.so.abi: Likewise. * tests/data/test-read-dwarf/test14-pr18893.so.abi: Likewise. * tests/data/test-read-dwarf/test15-pr18892.so.abi: Likewise. * tests/data/test-read-dwarf/test16-pr18904.so.abi: Likewise. * tests/data/test-read-dwarf/test17-pr19027.so.abi: Likewise. * tests/data/test-read-dwarf/test18-pr19037-libvtkRenderingLIC-6.1.so.abi: Likewise. * tests/data/test-read-dwarf/test19-pr19023-libtcmalloc_and_profiler.so.abi: Likewise. * tests/data/test-read-dwarf/test2.so.abi: Likewise. * tests/data/test-read-dwarf/test2.so.hash.abi: Likewise. * tests/data/test-read-dwarf/test20-pr19025-libvtkParallelCore-6.1.so.abi: Likewise. * tests/data/test-read-dwarf/test21-pr19092.so.abi: Likewise. * tests/data/test-read-dwarf/test22-pr19097-libstdc++.so.6.0.17.so.abi: Likewise. * tests/data/test-read-dwarf/test3-alias-1.so.hash.abi: Likewise. * tests/data/test-read-dwarf/test3-alias-2.so.hash.abi: Likewise. * tests/data/test-read-dwarf/test3-alias-3.so.hash.abi: Likewise. * tests/data/test-read-dwarf/test3-alias-4.so.hash.abi: Likewise. * tests/data/test-read-dwarf/test3.so.abi: Likewise. * tests/data/test-read-dwarf/test3.so.hash.abi: Likewise. * tests/data/test-read-dwarf/test4.so.abi: Likewise. * tests/data/test-read-dwarf/test4.so.hash.abi: Likewise. * tests/data/test-read-dwarf/test5.o.abi: Likewise. * tests/data/test-read-dwarf/test5.o.hash.abi: Likewise. * tests/data/test-read-dwarf/test6.so.abi: Likewise. * tests/data/test-read-dwarf/test6.so.hash.abi: Likewise. * tests/data/test-read-dwarf/test7.so.abi: Likewise. * tests/data/test-read-dwarf/test7.so.hash.abi: Likewise. * tests/data/test-read-dwarf/test8-qualified-this-pointer.so.abi: Likewise. * tests/data/test-read-dwarf/test8-qualified-this-pointer.so.hash.abi: Likewise. * tests/data/test-read-dwarf/test9-pr18818-clang.so.abi: Likewise. * tests/data/test-read-write/test-crc.xml: Likewise. * tests/data/test-read-write/test26.xml: Likewise. * tests/data/test-read-write/test27.xml: Likewise. * tests/data/test-read-write/test28-without-std-fns-ref.xml: Likewise. * tests/data/test-read-write/test28-without-std-vars-ref.xml: Likewise. Signed-off-by: Dodji Seketeli <dodji@redhat.com>
68 lines
2.7 KiB
Plaintext
68 lines
2.7 KiB
Plaintext
2.1 version
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===========
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This occurred in libabigail 2.1. The IR doesn't contain no-op
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qualified types anymore. These were the ancient way to represent
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qualified type that were edited by libabigail to avoid spurious
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diagnostics. E.g, const references or const void type. In those
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cases, we were replacing these by qualified types that were no-ops.
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Those no-ops qualified types further needed to be stripped off in the
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diff IR to avoid emitting spurious changes. It turned out stripping
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out those no-op qualified types was causing some difficulties in the
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algorithms that propagate type diff node categorization.
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For instance, variable diff type node would have the categorization of
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its diff->type_diff() be different from what we could see from the
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change observed between its diff->first_subject()->get_type() and
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diff->second_subject()->get_type(). This is because diff->type_diff()
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strips the no-op qualified types to create a new diff IR node, whereas
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looking at the difference between diff->first_subject->get_type() and
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diff->second_subject()->get_type() gives a different perspective.
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So looking at the "changes" carried by 'diff' could yield a result
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suggesting that there was a change to be diagnosed, carried by the
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difference between diff->first_subject()->get_type() and
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diff->second_subject()->get_type() -- a difference between two no-ops
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qualified types -- whereas actually looking at diff->type_diff() (that
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should be equivalent) yields a different information because it's
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stripped off of the no-op qualified type.
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Just removing the no-op qualified types removed all those issues
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altogether. So in concrete terms, when we see a const reference, it's
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replaced by a reference (because a reference is always const) and
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when we see a const void, it's replaced by void. As simple as that.
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But then the emitted ABIXML won't carry any no-op qualified type
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anymore. Older versions of ABIXML might still carry those, and so
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abidiff-ing those against their original binary might yield some
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spurious diagnostics. Hence the minor version bump.
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relevant commit:
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----------------
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commit 8a4f72005bc96fecf63414784cf94857eddbd124
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Author: Dodji Seketeli <dodji@redhat.com>
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Date: Thu Nov 4 10:59:32 2021 +0100
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Bug 28450 - Fix cloned member function handling in DWARF
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2.0 version
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===========
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This occured in libabigail 2.0. The interpretation of
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DW_AT_bit_offset (DWARF 5) changed so the value of the
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'layout-offset-in-bits' property of the 'data-member' element might
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now have changed in an incompatible way.
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relevant commit:
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----------------
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commit 23046152e0843bc2f141e37dcce047305c3f4379
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Author: Dodji Seketeli <dodji@redhat.com>
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Date: Thu Oct 22 16:04:08 2020 +0200
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Bump ABIXML format version to 2.0
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1.0 version
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===========
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This was the initial version of abixml.
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