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Pedro Alves 20944a6e20 Fix stepping past GNU ifunc resolvers (introduce lookup_msym_prefer)
When we're stepping (with "step"), we want to skip trampoline-like
functions automatically, including GNU ifunc resolvers.  That is done
by infrun.c calling into:

  in_solib_dynsym_resolve_code
    -> svr4_in_dynsym_resolve_code
      -> in_gnu_ifunc_stub

A problem here is that if there's a regular text symbol at the same
address as the ifunc symbol, the minimal symbol lookup in
in_gnu_ifunc_stub may miss the GNU ifunc symbol:

(...)
    41: 000000000000071a    53 FUNC    GLOBAL DEFAULT   11 gnu_ifunc_resolver
(...)
    50: 000000000000071a    53 IFUNC   GLOBAL DEFAULT   11 gnu_ifunc
(...)

This causes this FAIL in the tests added later in the series:

 (gdb) PASS: gdb.base/gnu-ifunc.exp: resolver_attr=1: resolver_debug=0: final_debug=0: resolver received HWCAP
 set step-mode on
 (gdb) PASS: gdb.base/gnu-ifunc.exp: resolver_attr=1: resolver_debug=0: final_debug=0: set step-mode on
 step
 0x00007ffff7bd371a in gnu_ifunc_resolver () from build/gdb/testsuite/outputs/gdb.base/gnu-ifunc/gnu-ifunc-lib-1-0-0.so
 (gdb) FAIL: gdb.base/gnu-ifunc.exp: resolver_attr=1: resolver_debug=0: final_debug=0: step

Above, GDB simply thought that it stepped into a regular function, so
it stopped stepping, while it should have continued stepping past the
resolver.

The fix is to teach minimal symbol lookup to prefer GNU ifunc symbols
if desired.

gdb/ChangeLog:
2018-04-26  Pedro Alves  <palves@redhat.com>

	* minsyms.c (lookup_minimal_symbol_by_pc_section_1): Rename to ...
	(lookup_minimal_symbol_by_pc_section): ... this.  Replace
	'want_trampoline' parameter by a lookup_msym_prefer parameter.
	Handle it.
	(lookup_minimal_symbol_by_pc_section): Delete old implementation.
	(lookup_minimal_symbol_by_pc): Adjust.
	(in_gnu_ifunc_stub): Prefer GNU ifunc symbols.
	(lookup_solib_trampoline_symbol_by_pc): Adjust.
	* minsyms.h (lookup_msym_prefer): New enum.
	(lookup_minimal_symbol_by_pc_section): Replace 'want_trampoline'
	parameter by a lookup_msym_prefer parameter.
2018-04-26 13:08:47 +01:00
bfd Automatic date update in version.in 2018-04-26 00:00:46 +00:00
binutils [ARM] FDPIC: Update testsuite so that many tests pass with arm*-uclinuxfdpiceabi. 2018-04-25 21:13:14 +00:00
config config: Sync with GCC 2018-04-05 15:22:13 -07:00
cpu
elfcpp PowerPC inline PLT call support 2018-04-09 17:25:20 +09:30
etc
gas x86: fold various non-memory operand AVX512VL templates 2018-04-26 08:55:02 +02:00
gdb Fix stepping past GNU ifunc resolvers (introduce lookup_msym_prefer) 2018-04-26 13:08:47 +01:00
gold Fix bug with relocation addends and merge sections with --icf. 2018-04-24 22:13:56 -07:00
gprof Updated Spanish translation for gprof directory 2018-04-18 12:02:17 +01:00
include [ARM] Add TLS relocations for FDPIC. 2018-04-25 20:57:02 +00:00
intl
ld [ARM] FDPIC: Update testsuite so that many tests pass with arm*-uclinuxfdpiceabi. 2018-04-25 21:13:14 +00:00
libdecnumber
libiberty Resync libiberty sources with master version in GCC repository. 2018-04-17 13:53:38 +01:00
opcodes x86: fold various non-memory operand AVX512VL templates 2018-04-26 08:55:02 +02:00
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		   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.