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The CTF variable section is an optional (usually-not-present) section in the CTF dict which contains name -> type mappings corresponding to data symbols that are present in the linker input but not in the output symbol table: the idea is that programs that use their own symbol- resolution mechanisms can use this section to look up the types of symbols they have found using their own mechanism. Because these removed symbols (mostly static variables, functions, etc) all have names that are unlikely to appear in the ELF symtab and because very few programs have their own symbol-resolution mechanisms, a special linker flag (--ctf-variables) is needed to emit this section. Historically, we emitted only removed data symbols into the variable section. This seemed to make sense at the time, but in hindsight it really doesn't: functions are symbols too, and a C program can look them up just like any other type. So extend the variable section so that it contains all static function symbols too (if it is emitted at all), with types of kind CTF_K_FUNCTION. This is a little fiddly. We relied on compiler assistance for data symbols: the compiler simply emits all data symbols twice, once into the symtypetab as an indexed symbol and once into the variable section. Rather than wait for a suitably adjusted compiler that does the same for function symbols, we can pluck unreported function symbols out of the symtab and add them to the variable section ourselves. While we're at it, we do the same with data symbols: this is redundant right now because the compiler does it, but it costs very little time and lets the compiler drop this kludge and save a little space in .o files. include/ * ctf.h: Mention the new things we can see in the variable section. ld/ * testsuite/ld-ctf/data-func-conflicted-vars.d: New test. libctf/ * ctf-link.c (ctf_link_deduplicating_variables): Duplicate symbols into the variable section too. * ctf-serialize.c (symtypetab_delete_nonstatic_vars): Rename to... (symtypetab_delete_nonstatics): ... this. Check the funchash when pruning redundant variables. (ctf_symtypetab_sect_sizes): Adjust accordingly. * NEWS: Describe this change.
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.