/* Target-dependent code for the GNU C Library (glibc).
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/* Target-dependent code for the GNU C Library (glibc).
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Copyright (C) 2002, 2003, 2007, 2008, 2009, 2010
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Copyright (C) 2002, 2003, 2007, 2008, 2009, 2010
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Free Software Foundation, Inc.
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Free Software Foundation, Inc.
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This file is part of GDB.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "defs.h"
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#include "frame.h"
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#include "frame.h"
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#include "symtab.h"
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#include "symtab.h"
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#include "symfile.h"
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#include "symfile.h"
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#include "objfiles.h"
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#include "objfiles.h"
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#include "glibc-tdep.h"
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#include "glibc-tdep.h"
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/* Calling functions in shared libraries. */
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/* Calling functions in shared libraries. */
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/* See the comments for SKIP_SOLIB_RESOLVER at the top of infrun.c.
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/* See the comments for SKIP_SOLIB_RESOLVER at the top of infrun.c.
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This function:
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This function:
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1) decides whether a PLT has sent us into the linker to resolve
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1) decides whether a PLT has sent us into the linker to resolve
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a function reference, and
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a function reference, and
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2) if so, tells us where to set a temporary breakpoint that will
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2) if so, tells us where to set a temporary breakpoint that will
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trigger when the dynamic linker is done. */
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trigger when the dynamic linker is done. */
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CORE_ADDR
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CORE_ADDR
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glibc_skip_solib_resolver (struct gdbarch *gdbarch, CORE_ADDR pc)
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glibc_skip_solib_resolver (struct gdbarch *gdbarch, CORE_ADDR pc)
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{
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{
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/* The GNU dynamic linker is part of the GNU C library, and is used
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/* The GNU dynamic linker is part of the GNU C library, and is used
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by all GNU systems (GNU/Hurd, GNU/Linux). An unresolved PLT
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by all GNU systems (GNU/Hurd, GNU/Linux). An unresolved PLT
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entry points to "_dl_runtime_resolve", which calls "fixup" to
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entry points to "_dl_runtime_resolve", which calls "fixup" to
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patch the PLT, and then passes control to the function.
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patch the PLT, and then passes control to the function.
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We look for the symbol `_dl_runtime_resolve', and find `fixup' in
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We look for the symbol `_dl_runtime_resolve', and find `fixup' in
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the same objfile. If we are at the entry point of `fixup', then
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the same objfile. If we are at the entry point of `fixup', then
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we set a breakpoint at the return address (at the top of the
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we set a breakpoint at the return address (at the top of the
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stack), and continue.
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stack), and continue.
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It's kind of gross to do all these checks every time we're
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It's kind of gross to do all these checks every time we're
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called, since they don't change once the executable has gotten
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called, since they don't change once the executable has gotten
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started. But this is only a temporary hack --- upcoming versions
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started. But this is only a temporary hack --- upcoming versions
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of GNU/Linux will provide a portable, efficient interface for
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of GNU/Linux will provide a portable, efficient interface for
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debugging programs that use shared libraries. */
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debugging programs that use shared libraries. */
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struct objfile *objfile;
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struct objfile *objfile;
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struct minimal_symbol *resolver
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struct minimal_symbol *resolver
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= lookup_minimal_symbol_and_objfile ("_dl_runtime_resolve", &objfile);
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= lookup_minimal_symbol_and_objfile ("_dl_runtime_resolve", &objfile);
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if (resolver)
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if (resolver)
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{
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{
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/* The dynamic linker began using this name in early 2005. */
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/* The dynamic linker began using this name in early 2005. */
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struct minimal_symbol *fixup
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struct minimal_symbol *fixup
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= lookup_minimal_symbol ("_dl_fixup", NULL, objfile);
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= lookup_minimal_symbol ("_dl_fixup", NULL, objfile);
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/* This is the name used in older versions. */
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/* This is the name used in older versions. */
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if (! fixup)
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if (! fixup)
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fixup = lookup_minimal_symbol ("fixup", NULL, objfile);
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fixup = lookup_minimal_symbol ("fixup", NULL, objfile);
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if (fixup && SYMBOL_VALUE_ADDRESS (fixup) == pc)
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if (fixup && SYMBOL_VALUE_ADDRESS (fixup) == pc)
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return frame_unwind_caller_pc (get_current_frame ());
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return frame_unwind_caller_pc (get_current_frame ());
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}
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}
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return 0;
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return 0;
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}
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}
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