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Targets such as xtensa incur a much higher overhead to resolve location view numbers than e.g. x86, because the expressions used to compute view numbers cannot be resolved soon enough. Each view number is computed by incrementing the previous view, if they are both at the same address, or by resetting it to zero otherwise. If PV is the previous view number, PL is its location, and NL is the location of the next view, its number is computed by evaluating NV = !(NL > PL) * (PV + 1). set_or_check_view uses resolve_expression to decide whether portions of this expression can be simplified to constants. The (NL > PL) subexpression is one that can often be resolved to a constant, breaking chains of view number computations at instructions of nonzero length, but not after alignment that might be unnecessary. Alas, when nearly every frag ends with a relaxable instruction, frag_offset_fixed_p will correctly fail to determine a known offset between two unresolved addresses in neighboring frags, so the unresolved symbolic operation will be constructed and used in the computation of most view numbers. This results in very deep expressions. As view numbers get referenced in location view lists, each operand in the list goes through symbol_clone_if_forward_ref, which recurses on every subexpression. If each view number were to be referenced, this would exhibit O(n^2) behavior, where n is the depth of the view number expressions, i.e., the length of view number sequences without an early resolution that cuts the expression short. This patch enables address compares used by view numbering to be resolved even when exact offsets are not known, using new logic to determine when the location either remained the same or changed for sure, even with the possibility of relaxation. This enables most view number expressions to be resolved with a small, reasonable depth. PR gas/24444 * frags.c (frag_gtoffset_p): New. * frags.h (frag_gtoffset_p): Declare it. * expr.c (resolve_expression): Use it.
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.