Binutils with MCST patches
4d354d8b89
I've always found the code in ARM backend of gas to control what CPU/architecture and FPU are selected by the user and to support autodetection of features complex and confusing. Chief among the issues I have with that code is the lack of comments to explain the meaning of the various variables. This patch addresses that and much more: - add comments to explain meaning of all arm_feature_set variables - keep track of currently selected CPU, extensions and FPU in a separate set of new variables - make naming of variable more consistent - remove dead code - simplify handling of extensions The overall approach is as follows: * restrict m*_opt variable to hold the feature bits of the corresponding mcpu/march/mfpu command-line options * record selected CPU, extensions and FPU in new selected_* during md_begin * whenever a .cpu/.arch/.arch_extension/.fpu directive is met, update the corresponding selected_* variables (eg. selected_arch, then selected_cpu for a .cpu or .arch directive) and then finally cpu_variant from them * pass extension feature set pointer by value to arm_parse_extension since it's only ever called from arm_parse_cpu and arm_parse_arch which allocate the extension feature set themselves * likewise, remove allocation from s_arm_arch_extension since the use of arm_feature_set structure for selected_ext rather than a pointer alleviate the need for it * in autodetection mode, only set all CPU fits in cpu_variant but leave selected_cpu* variables unset * in md_begin, remove dead "else if" to set a default FPU when no FPU was selected. Setting a default FPU based on CPU as did the code before it turn dead should be based on the default FPU field of the CPU and architecture table as will be done in a separate patch. Logic is wrong anyway since it sets VFP2 as default FPU for Armv6-M and Armv7-M Hopefully that should be enough to understand the change but if not feel free to ask questions about the patch. While I believe the new code is easier to understand, it remains complex and the old one was even more complex so the change is difficult to understand. 2018-03-01 Thomas Preud'homme <thomas.preudhomme@arm.com> gas/ * config/tc-arm.c (cpu_variant, arm_arch_used, thumb_arch_used, legacy_cpu, legacy_fpu, mcpu_cpu_opt, dyn_mcpu_ext_opt, mcpu_fpu_opt, march_cpu_opt, dyn_march_ext_opt, march_fpu_opt, mfpu_opt, object_arch, selected_cpu): Comment meaning of variables. (dyn_mcpu_ext_opt): Also rename into ... (mcpu_ext_opt): This. (dyn_march_ext_opt): Also rename into ... (march_ext_opt): This. (object_arch): Also rename into ... (selected_object_arch): This and make it a plain arm_feature_set structure. (selected_arch, selected_ext, selected_fpu): New static variables. (mark_feature_used): Fix comments, feature is marked as used iff it is currently allowed. (do_bx): Adapt to change in name and type of object_arch. (md_begin): Set selected_arch rather than mcpu_cpu_opt, selected_ext rather than dyn_mcpu_ext_opt and selected_fpu rather than mfpu_opt. Remove dead code to set default FPU if architecture version is greater than 5. Set all CPU bits of cpu_variant directly in autodection leaving mcpu_cpu_opt, selected_arch and selected_cpu unset. (arm_parse_extension): Take extension feature set pointer parameter by value rather than by pointer. Remove allocation code. Adapt code accordingly. (arm_parse_cpu): Adapt to variable renaming and changes in arm_parse_extension () signature. (arm_parse_arch): Likewise. (aeabi_set_public_attributes): Also set selected_arch and selected_ext in addition to selected_cpu. Set flags_arch and flags_ext from them instead of selected_cpu. Adapt to variables renaming and type change. (arm_md_post_relax): Adapt to variable renaming. (s_arm_cpu): Set selcted_cpu_cpu and selected_ext instead of mcpu_cpu_opt and dyn_mcpu_ext_opt. Set selected_cpu from them and cpu_variant from selected_cpu and selected_fpu. (s_arm_arch): Likewise. (s_arm_object_arch): Adapt to variable renaming. (s_arm_arch_extension): Use ARM_CPU_IS_ANY instead of checking feature set against arm_any. Check selected_arch rather than *mcpu_cpu_opt. Set selected_ext rather than *dyn_mcpu_ext_opt and remove allocation code. (s_arm_fpu): Set selected_fpu instead of mfpu_opt. Set all CPU feature bits if in autodetection mode. |
||
|---|---|---|
| bfd | ||
| binutils | ||
| config | ||
| cpu | ||
| elfcpp | ||
| etc | ||
| gas | ||
| gdb | ||
| gold | ||
| gprof | ||
| include | ||
| intl | ||
| ld | ||
| libdecnumber | ||
| libiberty | ||
| opcodes | ||
| readline | ||
| sim | ||
| texinfo | ||
| zlib | ||
| .cvsignore | ||
| .gitattributes | ||
| .gitignore | ||
| 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 | ||
| README | ||
| README-maintainer-mode | ||
| setup.com | ||
| src-release.sh | ||
| symlink-tree | ||
| 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.