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The Git repository of the Libabigail Project
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This patch teaches the ELF/DWARF reader of libabigail to load special
ELF sections that are specific to Linux Kernel binaries (either
vmlinux or linux kernel modules).
The patch creates a new flag that tells the ELF reader that it needs
to consider the input binary as a Linux Kernel binary. This is the
new 'Linux Kernel mode'.
In this linux kernel mode, the reader expects sections that are named
__ksymtab and/or __ksymtab_gpl sections. Those sections contain
indexes (of ELF symbols described in the normal ELF symbol table) of
exported ELF symbols that are specifically marked by developers using
EXPORT_SYMBOL or EXPORT_SYMBOL_GPL macros. These are symbols of
global variables and functions defined and meant to be used by kernel
modules. They constitute the interface exported by the Linux Kernel
to its modules. So the patch only exports the publicly defined and
exported ELF symbols that are also listed in __ksymtab and
__ksymtab_gpl sections.
The patch also fixes and re-organizes things left and right so that
this new mode works in a well integrated manner with the other parts
of the reader:
- The load address of the binary is no more assumed to be the load
address specified by the program header that is at offset zero.
This is usually the case for user-space programs. To handle Linux
Kernel binaries, the load address is now the one specified by the
program header that is at the smallest offset.
- The patch now tries to populate the various symbol maps only when
necessary. That way, the new symbol maps defined for the ksymtab
and ksymtab_gpl section are also loaded only when necessary; that
is, when in Linux Kernel mode.
- The patch (more) agressively suppresses non-member functions or
variables that are not declarations and that have no associated
ELF symbol.
The patch knows how to recognize and read relevant ELF symbol
information from __ksymtab and __ksymtab_gpl sections.
The patch makes abidiff and abidw detect that a binary is a
Linux Kernel binary (either a vmlinux or a module). It does this by
detecting the presence of the speciall __ksymtab_strings section.
If it detects that a binary is a Linux Kernel binary then it only
considers functions and variables which are defined and exported in
the sense of ELF *AND* which ELF symbols are listed in the __ksymtab
and __ksymtab_gpl sections.
If users want abidiff and abidw to consider their input binaries as
normal ELF binaries then they can use the option --no-linux-kernel-mode.
* include/abg-dwarf-reader.h (create_read_context): Take a new
flag to say if the context is to read an ELF binary in linux
kernel mode.
* src/abg-dwarf-reader.cc (typedef address_set_type)
(address_set_sptr): New typedefs.
(get_binary_load_address): The load address of the binary is
the load address specified by the program header that is at the
smallest offset; not by the program header that is at offset zero.
(read_context::{ksymtab_section_, ksymtab_gpl_section_,
linux_exported_fn_syms_, linux_exported_var_syms_,
linux_exported_gpl_fn_syms_, linux_exported_gpl_var_syms_,
load_in_linux_kernel_mode_}): New data members.
(read_context::read_context): Initialize ksymtab_section_,
ksymtab_gpl_section_ and load_in_linux_kernel_mode_.
(read_context::{find_symbol_table_section, find_opd_section,
lookup_elf_fn_symbol_from_address,
lookup_elf_var_symbol_from_address, get_function_address,
get_variable_address}): Make these const.
(read_context::{find_ksymtab_section, find_ksymtab_gpl_section,
lookup_elf_symbol_from_address, function_symbol_is_exported,
variable_symbol_is_exported, linux_exported_fn_syms,
create_or_get_linux_exported_fn_syms, linux_exported_var_syms,
create_or_get_linux_exported_var_syms, linux_exported_gpl_fn_syms,
linux_exported_gpl_var_syms,
create_or_get_linux_exported_gpl_fn_syms,
linux_exported_gpl_var_syms,
create_or_get_linux_exported_gpl_var_syms, architecture_word_size,
load_kernel_symbol_table, load_ksymtab_symbols,
load_ksymtab_gpl_symbols,
load_linux_specific_exported_symbol_maps,
load_in_linux_kernel_mode}): New member functions.
(read_context::read_int_from_array_of_bytes): Factorize this
new member function out of ...
(read_context::{lookup_ppc64_elf_fn_entry_point_address}):
... this. Make this function const too.
(read_context::read_uint64_from_array_of_bytes): New function.
Uses read_int_from_array_of_bytes above.
(read_context::{fun_entry_addr_sym_map_sptr}): Try to load symbol
maps only when it's necessary.
(read_context::elf_architecture_is_big_endian): Fix logic.
(read_context::{var_addr_sym_map}): Express the const variant in
terms of the non-const one. In the non-const one, load the map
only when necessary.
(read_context::load_symbol_maps_from_symtab_section): Renamed
load_symbol_maps into this.
(read_context::is_linux_kernel_binary): Define new member
function.
(read_context::{function, variable}_symbol_is_exported): If we are
not prevented from considering loading in linux kernel mode, then
just looking at a linux kernel binary makes us consider the
special kernel sections.
(read_debug_info_into_corpus): Likewise.
(build_ir_node_from_die): Take a new flag that says if the ir node
is a declaration required by another concrete IR node.
(enum read_context::kernel_symbol_table_kind): New enum.
(read_context::load_symbol_maps): Support loading linux kernel
specific sections too.
(build_var_decl): Use the new
read_context::variable_symbol_is_exported.
(function_is_suppressed): Suppress non-member functions or
variables that are not declarations and that have no symbol.
(variable_is_suppressed, build_var_decl_if_not_suppressed): Take a
new flag that says if the variable is a declaration required by a
concrete variable. If non member variable that is a declaration
is not the specification of another concrete variable, then it's
suppressed.
(add_fn_symbols_to_map, add_var_symbols_to_map): New function
definitions.
(read_debug_info_into_corpus): If we are reading linux kernel or
linux kernel modules, only set explicitely exported symbols (in
the linux kernel binary sense) as exported function or variable
symbols.
(create_read_context): Take a new flag to say if the context is to
read an ELF binary in linux kernel mode.
* tools/abidiff.cc (options::options): Initialize
options::linux_kernel_mode to true.
(display_usage): Display usage of the --no-linux-kernel-mode option.
(parse_command_line): Parse the --no-linux-kernel-mode option.
* tools/abidw.cc (options::options): Initialize
options::linux_kernel_mode to true.
(display_usage): Display usage of --no-linux-kernel-mode option.
(parse_command_line): Parse the --no-linux-kernel-mode option.
* doc/manuals/abidiff.rst: Document the new --no-linux-kernel-mode
options.
* doc/manuals/abidw.rst: Likewise.
* tests/data/test-diff-dwarf-abixml/test0-pr19026-libvtkIOSQL-6.1.so.1.abi:
Adjust.
* tests/data/test-read-dwarf/test9-pr18818-clang.so.abi: Adjust.
* tests/data/test-read-dwarf/test10-pr18818-gcc.so.abi: Adjust.
* tests/data/test-read-dwarf/test11-pr18828.so.abi: Adjust.
* tests/data/test-read-dwarf/test12-pr18844.so.abi: Likewise.
* tests/data/test-read-dwarf/test13-pr18894.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/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/libtest23.so.abi: Adjust.
* tests/data/test-read-dwarf/libtest24-drop-fns-2.so.abi: Adjust.
* tests/data/test-read-dwarf/libtest24-drop-fns.so.abi: Adjust.
Signed-off-by: Dodji Seketeli <dodji@redhat.com>
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| autoconf-archive | ||
| bash-completion | ||
| doc | ||
| include | ||
| m4 | ||
| scripts | ||
| src | ||
| tests | ||
| tools | ||
| .gitignore | ||
| abigail.m4 | ||
| AUTHORS | ||
| ChangeLog | ||
| COMMIT-LOG-GUIDELINES | ||
| COMPILING | ||
| configure.ac | ||
| CONTRIBUTING | ||
| COPYING | ||
| COPYING-GPLV3 | ||
| COPYING-LGPLV2 | ||
| COPYING-LGPLV3 | ||
| default.abignore | ||
| gen-changelog.py | ||
| install-sh | ||
| libabigail.pc.in | ||
| ltmain.sh | ||
| Makefile.am | ||
| NEWS | ||
| README | ||
| release-text-template.txt | ||
| VISIBILITY | ||
This is the Application Binary Interface Generic Analysis and Instrumentation Library. It aims at constructing, manipulating, serializing and de-serializing ABI-relevant artifacts. The set of artifacts that we are intersted is made of quantities like types, variable, fonctions and declarations of a given library or program. For a given library or program this set of quantities is called an ABI corpus. This library aims at (among other things) providing a way to compare two ABI Corpora (apparently the plural of corpus is copora, heh, that's cool), provide detailed information about their differences, and help build tools to infer interesting conclusions about these differences. You are welcome to contribute to this project after reading the files CONTRIBUTING and COMMIT-LOG-GUIDELINES files in the source tree. Communicating with the maintainers of this project -- including sending patches to be include to the source code -- happens via email at libabigail@sourceware.org.