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For synthesizing CFI (SCFI) for hand-written asm, the SCFI machinery in GAS works on the generic GAS insns (ginsns). This patch adds support in the aarch64 backend to create ginsns for a subset of the supported machine instructions. The subset includes the minimal necessary instructions to ensure SCFI correctness: - Any potential register saves and unsaves. Hence, process instructions belonging to a variety of iclasses involving str, ldr, stp, ldp. - Any change of flow instructions. This includes all conditional and unconditional branches, call (bl, blr, etc.) and return. - Most importantly, any instruction that could affect the two registers of interest: REG_SP, REG_FP. This set includes all pre-indexed and post-indexed memory operations, with writeback, on the stack. This set must also include other instructions (e.g., arithmetic insns) where the destination register is one of the afore-mentioned registers. With respect to callee-saved registers in Aarch64, FP/Advanced SIMD registers D8-D15 are included along with the relevant GPRs. Calculating offsets for loads and stores especially for Q registers needs special attention here. As an example, str q8, [sp, #16] On big-endian: STR Qn stores as a 128-bit integer (MSB first), hence, should record D8 as being saved at sp+24 rather than sp+16. On little-endian: should record D8 as being saved at sp+16 D8-D15 are the low 64 bits of Q8-Q15, and of Z8-Z15 if SVE is used; hence, they remain "interesting" for SCFI purposes in such cases. A CFI save slot always represents the low 64 bits, regardless of whether a save occurs on D, Q or Z registers. Currently, the ginsn creation machinery can handle D and Q registers on little-endian and big-endian. Apart from creating ginsn, another key responsibility of the backend is to make sure there are safeguards in place to detect and alert if an instruction of interest may have been skipped. This is done via aarch64_ginsn_unhandled () (similar to the x86 backend). This function , hence, is also intended to alert when future ISA changes may otherwise render SCFI results incorrect, because of missing ginsns for the newly added machine instructions. At this time, becuase of the complexities wrt endianness in handling Z register usage, skip sve_misc opclass altogether for now. The SCFI machinery will error out (using the aarch64_ginsn_unhandled () code path) though if Z register usage affects correctness. The current SCFI machinery does not currently synthesize the PAC-related, aarch64-specific CFI directives: .cfi_b_key_frame. The support for this is planned for near future. SCFI is enabled for ELF targets only. gas/ * config/tc-aarch64-ginsn.c: New file. * config/tc-aarch64.c (md_assemble): Include tc-aarch64-ginsn.c file. Invoke aarch64_ginsn_new. * config/tc-aarch64.h (TARGET_USE_GINSN): Define for SCFI enablement. (TARGET_USE_SCFI): Likewise. (SCFI_MAX_REG_ID): New definition. (REG_FP): Likewise. (REG_LR): Likewise. (REG_SP): Likewise. (SCFI_INIT_CFA_OFFSET): Likewise. (SCFI_CALLEE_SAVED_REG_P): Likewise. (aarch64_scfi_callee_saved_p): New declaration. |
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| bfd | ||
| binutils | ||
| config | ||
| contrib | ||
| cpu | ||
| elfcpp | ||
| etc | ||
| gas | ||
| gdb | ||
| gdbserver | ||
| gdbsupport | ||
| gnulib | ||
| gold | ||
| gprof | ||
| gprofng | ||
| include | ||
| ld | ||
| libbacktrace | ||
| libctf | ||
| libdecnumber | ||
| libiberty | ||
| libsframe | ||
| opcodes | ||
| readline | ||
| sim | ||
| texinfo | ||
| zlib | ||
| .cvsignore | ||
| .editorconfig | ||
| .gitattributes | ||
| .gitignore | ||
| .pre-commit-config.yaml | ||
| ar-lib | ||
| ChangeLog | ||
| compile | ||
| config-ml.in | ||
| config.guess | ||
| config.rpath | ||
| config.sub | ||
| configure | ||
| configure.ac | ||
| COPYING | ||
| COPYING3 | ||
| COPYING3.LIB | ||
| COPYING.LIB | ||
| COPYING.LIBGLOSS | ||
| COPYING.NEWLIB | ||
| depcomp | ||
| djunpack.bat | ||
| install-sh | ||
| libtool.m4 | ||
| lt~obsolete.m4 | ||
| ltgcc.m4 | ||
| ltmain.sh | ||
| ltoptions.m4 | ||
| ltsugar.m4 | ||
| ltversion.m4 | ||
| MAINTAINERS | ||
| Makefile.def | ||
| Makefile.in | ||
| Makefile.tpl | ||
| makefile.vms | ||
| missing | ||
| mkdep | ||
| mkinstalldirs | ||
| move-if-change | ||
| multilib.am | ||
| README | ||
| README-maintainer-mode | ||
| SECURITY.txt | ||
| setup.com | ||
| src-release.sh | ||
| symlink-tree | ||
| test-driver | ||
| ylwrap | ||
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.