libdwfl: Introduce dwfl_module_getsym_info and dwfl_module_addrinfo.

Some arches like ppc64 use function descriptor values instead of function
addresses causing matching of names and addresses to fail when using
dwfl_module_getsym or dwfl_module_addrsym.

Add ebl hook to resolve any function descriptor values found in non-ET_REL
modules.

The new function dwfl_module_getsym_info doesn't adjust the symbol value
in any way, but returns the adjusted and/or resolved address associated
with the symbol separately. The new function dwfl_module_addrinfo resolves
against both the address associated with the symbol (which could be the
function entry address) value and the adjusted st_value. So that it is
easy to resolve and match either function descriptors and/or function
entry addresses.

Since these new functions also return more information they replace the
dwfl_module_getsym_elf and dwfl_module_addrsym_elf functions that never
made it into a released elfutils version.

addr2line and readelf now use the new functions when looking up functions
names. addr2line will now also display the section the address was found
in when given -x.

Extra testcases were added for both addr2line and the dwflsyms testscase.

Signed-off-by: Mark Wielaard <mjw@redhat.com>

6 files changed, 69 insertions, 1 deletions

diff --git a/libebl/ChangeLog b/libebl/ChangeLog
index f1aa242b..fc6bdd56 100644
--- a/libebl/ChangeLog
+++ b/libebl/ChangeLog
@@ -1,3 +1,12 @@
+2013-12-18  Mark Wielaard  <mjw@redhat.com>
+
+	* Makefile.am (gen_SOURCES): Add eblresolvesym.c.
+	* ebl-hooks.h (resolve_sym_value): New entry.
+	* eblresolvesym.c: New file.
+	* libebl.h (ebl_resolve_sym_value): New definition.
+	* libeblP.h (fd_addr): New field.
+	(fd_data): Likewise.
+
 2013-12-18  Jan Kratochvil  <jan.kratochvil@redhat.com>
 
 	unwinder: s390 and s390x
diff --git a/libebl/Makefile.am b/libebl/Makefile.am
index fc4f1b6f..916af72a 100644
--- a/libebl/Makefile.am
+++ b/libebl/Makefile.am
@@ -55,7 +55,7 @@ gen_SOURCES = eblopenbackend.c eblclosebackend.c eblstrtab.c \
 	      eblsysvhashentrysize.c eblauxvinfo.c eblcheckobjattr.c \
 	      ebl_check_special_section.c ebl_syscall_abi.c eblabicfi.c \
 	      eblstother.c eblinitreg.c ebldwarftoregno.c eblnormalizepc.c \
-	      eblunwind.c
+	      eblunwind.c eblresolvesym.c
 
 libebl_a_SOURCES = $(gen_SOURCES)
 
diff --git a/libebl/ebl-hooks.h b/libebl/ebl-hooks.h
index 22438953..bfb7f4a9 100644
--- a/libebl/ebl-hooks.h
+++ b/libebl/ebl-hooks.h
@@ -183,5 +183,10 @@ bool EBLHOOK(unwind) (Ebl *ebl, Dwarf_Addr pc, ebl_tid_registers_t *setfunc,
 		      ebl_pid_memory_read_t *readfunc, void *arg,
 		      bool *signal_framep);
 
+/* Returns true if the value can be resolved to an address in an
+   allocated section, which will be returned in *SHNDXP.
+   (e.g. function descriptor resolving)  */
+bool EBLHOOK(resolve_sym_value) (Ebl *ebl, GElf_Addr *addr);
+
 /* Destructor for ELF backend handle.  */
 void EBLHOOK(destr) (struct ebl *);
diff --git a/libebl/eblresolvesym.c b/libebl/eblresolvesym.c
new file mode 100644
index 00000000..470f6f06
--- /dev/null
+++ b/libebl/eblresolvesym.c
@@ -0,0 +1,43 @@
+/* Resolve a symbol value to an allocated section of the Elf file.
+   Copyright (C) 2013 Red Hat, Inc.
+   This file is part of elfutils.
+
+   This file is free software; you can redistribute it and/or modify
+   it under the terms of either
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at
+       your option) any later version
+
+   or
+
+     * the GNU General Public License as published by the Free
+       Software Foundation; either version 2 of the License, or (at
+       your option) any later version
+
+   or both in parallel, as here.
+
+   elfutils is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <libeblP.h>
+#include <assert.h>
+
+bool
+ebl_resolve_sym_value (Ebl *ebl, GElf_Addr *addr)
+{
+  if (ebl == NULL || ebl->resolve_sym_value == NULL)
+    return false;
+
+  return ebl->resolve_sym_value (ebl, addr);
+}
diff --git a/libebl/libebl.h b/libebl/libebl.h
index 84c2f4cd..50d6baab 100644
--- a/libebl/libebl.h
+++ b/libebl/libebl.h
@@ -439,6 +439,12 @@ extern bool ebl_unwind (Ebl *ebl, Dwarf_Addr pc, ebl_tid_registers_t *setfunc,
 			bool *signal_framep)
   __nonnull_attribute__ (1, 3, 4, 5, 7);
 
+/* Returns true if the value can be resolved to an address in an
+   allocated section, which will be returned in *ADDR
+   (e.g. function descriptor resolving)  */
+extern bool ebl_resolve_sym_value (Ebl *ebl, GElf_Addr *addr)
+   __nonnull_attribute__ (2);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/libebl/libeblP.h b/libebl/libeblP.h
index 4f4137d5..f91c2a0d 100644
--- a/libebl/libeblP.h
+++ b/libebl/libeblP.h
@@ -64,6 +64,11 @@ struct ebl
      Ebl architecture can unwind iff FRAME_NREGS > 0.  */
   size_t frame_nregs;
 
+  /* Function descriptor load address and table as used by
+     ebl_resolve_sym_value if available for this arch.  */
+  GElf_Addr fd_addr;
+  Elf_Data *fd_data;
+
   /* Internal data.  */
   void *dlhandle;
 };