23cedd1dc9
In addition to the existing relocs we need two more to mark all instructions in the call sequence, PLTCALL on the call itself (plus the toc restore insn for ppc64), and PLTSEQ on others. All relocations in a particular sequence have the same symbol. Example ppc64 ELFv2 assembly: .reloc .,R_PPC64_PLTSEQ,puts std 2,24(1) addis 12,2,puts@plt@ha # .reloc .,R_PPC64_PLT16_HA,puts ld 12,puts@plt@l(12) # .reloc .,R_PPC64_PLT16_LO_DS,puts .reloc .,R_PPC64_PLTSEQ,puts mtctr 12 .reloc .,R_PPC64_PLTCALL,puts bctrl ld 2,24(1) Example ppc32 -fPIC assembly: addis 12,30,puts+32768@plt@ha # .reloc .,R_PPC_PLT16_HA,puts+0x8000 lwz 12,12,puts+32768@plt@l # .reloc .,R_PPC_PLT16_LO,puts+0x8000 .reloc .,R_PPC_PLTSEQ,puts+32768 mtctr 12 .reloc .,R_PPC_PLTCALL,puts+32768 bctrl Marking sequences like this allows the linker to convert them to nops and a direct call if the target symbol turns out to be local. When the call is __tls_get_addr, each relocation shown above is paired with an R_PPC*_TLSLD or R_PPC*_TLSGD reloc to additionally mark the sequence for possible TLS optimization. The TLSLD or TLSGD relocs are emitted first. include/ * elf/ppc.h (R_PPC_PLTSEQ, R_PPC_PLTCALL): Define. * elf/ppc64.h (R_PPC64_PLTSEQ, R_PPC64_PLTCALL): Define. bfd/ * elf32-ppc.c (ppc_elf_howto_raw): Add PLTSEQ and PLTCALL howtos. (is_plt_seq_reloc): New function. (ppc_elf_check_relocs): Handle PLTSEQ and PLTCALL relocs. (ppc_elf_tls_optimize): Handle inline plt call sequence. (ppc_elf_relax_section): Handle PLTCALL reloc. (ppc_elf_relocate_section): Nop out inline plt call sequence when resolving locally. * elf64-ppc.c (ppc64_elf_howto_raw): Add R_PPC64_PLTSEQ and R_PPC64_PLTCALL entries. Comment R_PPC64_TOCSAVE. (has_tls_get_addr_call): Correct comment. (is_branch_reloc): Add PLTCALL. (is_plt_seq_reloc): New function. (ppc64_elf_check_relocs): Handle PLT16_LO_DS reloc. Set has_tls_reloc for R_PPC64_TLSGD and R_PPC64_TLSLD. Create plt entry for R_PPC64_PLTCALL. (ppc64_elf_tls_optimize): Handle inline plt call sequence. (ppc_type_of_stub): Handle PLTCALL reloc. (toc_adjusting_stub_needed): Likewise. (ppc64_elf_relocate_section): Set "can_plt_call" for PLTCALL reloc insn. Nop out inline plt call sequence when resolving locally. Handle __tls_get_addr inline plt call optimization. elfcpp/ * powerpc.h (R_POWERPC_PLTSEQ, R_POWERPC_PLTCALL): Define. gold/ * powerpc.cc (Target_powerpc::Track_tls::maybe_skip_tls_get_addr_call): Handle inline plt sequence relocs. (Stub_table::Plt_stub_key::Plt_stub_key): Likewise. (Target_powerpc::Scan::reloc_needs_plt_for_ifunc): Likewise. (Target_powerpc::Relocate::relocate): Likewise.
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.