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This patch fixes the bug in my patch skipping stack protector https://www.sourceware.org/ml/gdb-patches/2010-12/msg00110.html In my skipping stack protector patch, I misunderstood the constant vs. immediate on instruction encodings, and treated immediate as constant by mistake. The instruction 'ldr Rd, [PC, #immed]' loads the address of __stack_chk_guard to Rd, and #immed is an offset from PC. We should get the __stack_chk_guard from *(pc + #immed). As a result of this mistake, arm_analyze_load_stack_chk_guard returns the wrong address of __stack_chk_guard, and the symbol __stack_chk_guard can't be found. However, we continue to match the following instructions when symbol isn't found, so the code still works. In other words, the code just matches the instruction pattern without checking __stack_chk_guard symbol correctly. Joel's patch <https://sourceware.org/ml/gdb-patches/2014-10/msg00605.html> makes the heuristics stricter that we stop matching instructions if symbol __stack_chk_guard isn't found. Then the bug is exposed. This patch is to correct the load address computation for ldr instruction, and it fixes some fails in gdb.mi/gdb792.exp on armv4t both arm and thumb mode. Regression tested on arm-linux-gnueabi target with {armv4t, armv7-a} x {marm, mthumb} x {-fstack-protector,-fno-stack-protector} gdb: 2014-10-29 Yao Qi <yao@codesourcery.com> * arm-tdep.c (arm_analyze_load_stack_chk_guard): Compute the loaded address correctly of ldr instruction.
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.