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Link-time relaxations of branches are common for MSP430, given that GCC
can generate pessimal branch instructions, and the
-mcode-region=either/-mdata-region=either options to shuffle sections
can further change the type of branch instruction required.
These relaxations can result in invalid code when .uleb128
directives, used in the .gcc_except_table section, are used to calculate
the distance between two labels. A value for the .uleb128 directive is
calculated at assembly-time, and can't be updated at link-time, even if
relaxation causes the distance between the labels to change.
This patch adds relocations for subtract expressions in .uleb128
directives, to allow the linker to re-calculate the value of these
expressions after relaxation has been performed.
bfd/ChangeLog:
* bfd-in2.h (bfd_reloc_code_real): Add
BFD_RELOC_MSP430_{SET,SUB}_ULEB128.
* elf32-msp430.c (msp430_elf_ignore_reloc): New.
(elf_msp430_howto_table): Add R_MSP430{,X}_GNU_{SET,SUB}_ULEB128.
(msp430_reloc_map): Add R_MSP430_GNU_{SET,SUB}_ULEB128.
(msp430x_reloc_map): Add R_MSP430X_GNU_{SET,SUB}_ULEB128.
(write_uleb128): New.
(msp430_final_link_relocate): Handle R_MSP430{,X}_GNU_{SET,SUB}_ULEB128.
* libbfd.c (_bfd_write_unsigned_leb128): New.
* libbfd.h (_bfd_write_unsigned_leb128): New prototype.
Add BFD_RELOC_MSP430_{SET,SUB}_ULEB128.
* reloc.c: Document BFD_RELOC_MSP430_{SET,SUB}_ULEB128.
binutils/ChangeLog:
* readelf.c (target_specific_reloc_handling): Handle
R_MSP430{,X}_GNU_{SET,SUB}_ULEB128.
gas/ChangeLog:
* config/tc-msp430.c (msp430_insert_uleb128_fixes): New.
(msp430_md_end): Call msp430_insert_uleb128_fixes.
include/ChangeLog:
* elf/msp430.h (elf_msp430_reloc_type): Add
R_MSP430_GNU_{SET,SUB}_ULEB128.
(elf_msp430x_reloc_type): Add R_MSP430X_GNU_{SET,SUB}_ULEB128.
ld/ChangeLog:
* testsuite/ld-msp430-elf/msp430-elf.exp: Run new tests.
* testsuite/ld-msp430-elf/uleb128.s: New test.
* testsuite/ld-msp430-elf/uleb128_430.d: New test.
* testsuite/ld-msp430-elf/uleb128_430x.d: New test.
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.