RFA: libunwind basic support

["J. Johnston" <jjohnstn at redhat dot com>]

The attached patch adds basic libunwind frame support.  I will be shortly 
submitting an ia64-tdep.c patch which works in conjunction with this patch.  The 
libunwind code is protected by looking for the libunwind header files to 
compile.  At runtime, the libunwind frame sniffer will fail if either the 
libunwind library cannot be dynamically loaded or the frame in question does not 
have proper libunwind info.

For configuration I have added checks for libunwind.h and libunwind-ia64.h as 
this is being added for ia64 support only at present.  Regarding testing, I have 
this code working with my ia64 changes.  I have tested on systems with the 
libunwind-0.92 library/headers installed and not installed.

Ok to commit?

2003-10-15  Jeff Johnston  <jjohnstn@redhat.com>

	* libunwind-frame.c: New file.
	* libunwind-frame.h: New file.
	* configure.in: Add checks for libunwind.h and libunwind-ia64.h.
	* configure: Regenerated.
	* Makefile.in: Add support for libunwind-frame.o.
	* config.in: Regenerated.


Index: libunwind-frame.c
===================================================================
RCS file: libunwind-frame.c
diff -N libunwind-frame.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ libunwind-frame.c	15 Oct 2003 21:13:26 -0000
@@ -0,0 +1,349 @@
+/* Frame unwinder for frames using the libunwind library.
+
+   Copyright 2003 Free Software Foundation, Inc.
+
+   Contributed by Jeff Johnston
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of 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.
+
+   This program 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 a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include "defs.h"
+
+#ifdef HAVE_LIBUNWIND_H
+
+#include "inferior.h"
+#include "frame.h"
+#include "frame-base.h"
+#include "frame-unwind.h"
+#include "gdbcore.h"
+#include "gdbtypes.h"
+#include "symtab.h"
+#include "objfiles.h"
+#include "regcache.h"
+
+#include <dlfcn.h>
+
+#include "gdb_assert.h"
+#include "gdb_string.h"
+
+#include "libunwind-frame.h"
+
+#include "complaints.h"
+
+static int libunwind_initialized;
+static struct gdbarch_data *libunwind_descr_handle;
+
+#ifndef LIBUNWIND_SO
+#define LIBUNWIND_SO "libunwind.so"
+#endif
+
+/* Required function pointers from libunwind.  */
+static int (*unw_get_reg_p) (unw_cursor_t *, unw_regnum_t, unw_word_t *);
+static int (*unw_get_fpreg_p) (unw_cursor_t *, unw_regnum_t, unw_fpreg_t *);
+static int (*unw_get_saveloc_p) (unw_cursor_t *, unw_regnum_t, unw_save_loc_t *);
+static int (*unw_step_p) (unw_cursor_t *);
+static int (*unw_init_remote_p) (unw_cursor_t *, unw_addr_space_t, void *);
+static unw_addr_space_t (*unw_create_addr_space_p) (unw_accessors_t *, int);
+static int (*unw_search_unwind_table_p) (unw_addr_space_t, unw_word_t, unw_dyn_info_t *,
+					 unw_proc_info_t *, int, void *);
+static unw_word_t (*unw_find_dyn_list_p) (unw_addr_space_t, void *, size_t,
+					  unw_word_t, unw_word_t, void *);
+
+
+struct libunwind_frame_cache
+{
+  CORE_ADDR base;
+  CORE_ADDR func_addr;
+  unw_cursor_t cursor;
+};
+
+#define STRINGIFY2(name)	#name
+#define STRINGIFY(name)		STRINGIFY2(name)
+
+static char *get_reg_name = STRINGIFY(UNW_OBJ(get_reg));
+static char *get_fpreg_name = STRINGIFY(UNW_OBJ(get_fpreg));
+static char *get_saveloc_name = STRINGIFY(UNW_OBJ(get_saveloc));
+static char *step_name = STRINGIFY(UNW_OBJ(step));
+static char *init_remote_name = STRINGIFY(UNW_OBJ(init_remote));
+static char *create_addr_space_name = STRINGIFY(UNW_OBJ(create_addr_space));
+static char *search_unwind_table_name = STRINGIFY(UNW_OBJ(search_unwind_table));
+static char *find_dyn_list_name = STRINGIFY(UNW_OBJ(find_dyn_list));
+
+void
+libunwind_set_descr_handle (void *handle)
+{
+  libunwind_descr_handle = handle;
+}
+
+static struct libunwind_descr *
+libunwind_descr (struct gdbarch *gdbarch)
+{
+  return gdbarch_data (gdbarch, libunwind_descr_handle);
+}
+
+static struct libunwind_frame_cache *
+libunwind_frame_cache (struct frame_info *next_frame, void **this_cache)
+{
+  unw_accessors_t *acc;
+  unw_addr_space_t as;
+  unw_word_t fp;
+  unw_regnum_t uw_sp_regnum;
+  struct libunwind_frame_cache *cache;
+  struct libunwind_descr *descr;
+  int i, ret;
+
+  if (*this_cache)
+    return *this_cache;
+
+  /* Allocate a new cache.  */
+  cache = FRAME_OBSTACK_ZALLOC (struct libunwind_frame_cache);
+
+  cache->func_addr = frame_func_unwind (next_frame);
+
+  /* Get a cursor to the previous frame.  We do this by initializing
+     a cursor and stepping back to the frame level prior to the one we are 
+     currently in.  */
+  descr = libunwind_descr (get_frame_arch (next_frame));
+  acc = descr->accessors;
+  as =  unw_create_addr_space_p (acc,
+				 TARGET_BYTE_ORDER == BFD_ENDIAN_BIG
+				 ? __BIG_ENDIAN
+				 : __LITTLE_ENDIAN);
+
+  unw_init_remote_p (&cache->cursor, as, next_frame);
+  unw_step_p (&cache->cursor);
+
+  /* To get base address, get sp from previous frame.  */
+  uw_sp_regnum = descr->gdb2uw (SP_REGNUM);
+  ret = unw_get_reg_p (&cache->cursor, uw_sp_regnum, &fp);
+  if (ret < 0)
+    error ("Can't get libunwind sp register.");
+
+  cache->base = (CORE_ADDR)fp;
+
+  *this_cache = cache;
+  return cache;
+}
+
+unw_word_t 
+libunwind_find_dyn_list (unw_addr_space_t as, void *table, size_t table_size,
+			 unw_word_t segbase, unw_word_t gp, void *arg)
+{
+  return unw_find_dyn_list_p (as, table, table_size, segbase, gp, arg);
+}
+
+static const struct frame_unwind libunwind_frame_unwind =
+{
+  NORMAL_FRAME,
+  libunwind_frame_this_id,
+  libunwind_frame_prev_register
+};
+
+const struct frame_unwind *
+libunwind_frame_sniffer (struct frame_info *next_frame)
+{
+  unw_cursor_t cursor;
+  unw_accessors_t *acc;
+  unw_addr_space_t as;
+  struct libunwind_descr *descr;
+  int i, ret;
+
+  /* Get a cursor to the previous frame.  We do this by initializing
+     a cursor and stepping back to the frame level prior to the one we are 
+     currently in.  */
+  descr = libunwind_descr (get_frame_arch (next_frame));
+  acc = descr->accessors;
+  as =  unw_create_addr_space_p (acc,
+				 TARGET_BYTE_ORDER == BFD_ENDIAN_BIG
+				 ? __BIG_ENDIAN
+				 : __LITTLE_ENDIAN);
+
+  ret = unw_init_remote_p (&cursor, as, next_frame);
+
+  if (ret >= 0)
+    ret = unw_step_p (&cursor);
+
+  if (ret < 0)
+    return NULL;
+
+  return &libunwind_frame_unwind;
+}
+
+void
+libunwind_frame_this_id (struct frame_info *next_frame, void **this_cache,
+		      struct frame_id *this_id)
+{
+  struct libunwind_frame_cache *cache =
+    libunwind_frame_cache (next_frame, this_cache);
+
+  (*this_id) = frame_id_build (cache->base, cache->func_addr);
+}
+
+void
+libunwind_frame_prev_register (struct frame_info *next_frame, void **this_cache,
+			       int regnum, int *optimizedp,
+			       enum lval_type *lvalp, CORE_ADDR *addrp,
+			       int *realnump, void *valuep)
+{
+  struct libunwind_frame_cache *cache =
+    libunwind_frame_cache (next_frame, this_cache);
+
+  void *ptr;
+  unw_cursor_t *c;
+  unw_save_loc_t sl;
+  int i, ret;
+  unw_word_t intval;
+  unw_fpreg_t fpval;
+  unw_regnum_t uw_regnum;
+  struct libunwind_descr *descr;
+
+  descr = libunwind_descr (get_frame_arch (next_frame));
+  uw_regnum = descr->gdb2uw (regnum);
+
+  gdb_assert (regnum >= 0);
+
+  if (!target_has_registers)
+    error ("No registers.");
+
+  *optimizedp = 0;
+  *addrp = 0;
+  *lvalp = not_lval;
+  *realnump = -1;
+
+  memset (valuep, 0, DEPRECATED_REGISTER_RAW_SIZE (regnum));
+
+  if (uw_regnum < 0)
+    return;
+
+  if (descr->is_fpreg (uw_regnum))
+    {
+      ret = unw_get_fpreg_p (&cache->cursor, uw_regnum, &fpval);
+      ptr = &fpval;
+    }
+  else
+    {
+      ret = unw_get_reg_p (&cache->cursor, uw_regnum, &intval);
+      ptr = &intval;
+    }
+
+  if (ret < 0)
+    return;
+
+  memcpy (valuep, ptr, DEPRECATED_REGISTER_RAW_SIZE (regnum));
+
+  if (unw_get_saveloc_p (&cache->cursor, uw_regnum, &sl) < 0)
+    return;
+
+  switch (sl.type)
+    {
+    case UNW_SLT_NONE:
+      *optimizedp = 1;
+      break;
+
+    case UNW_SLT_MEMORY:
+      *lvalp = lval_memory;
+      *addrp = sl.u.addr;
+      break;
+
+    case UNW_SLT_REG:
+      *lvalp = lval_register;
+      *realnump = regnum;
+      break;
+    }
+} 
+
+CORE_ADDR
+libunwind_frame_base_address (struct frame_info *next_frame, void **this_cache)
+{
+  struct libunwind_frame_cache *cache =
+    libunwind_frame_cache (next_frame, this_cache);
+
+  return cache->base;
+}
+
+int
+libunwind_search_unwind_table (void *as, long ip, void *di,
+			       void *pi, int need_unwind_info, void *args)
+{
+  return unw_search_unwind_table_p (*(unw_addr_space_t *)as, (unw_word_t )ip, 
+				    di, pi, need_unwind_info, args);
+}
+
+static int
+libunwind_load (void)
+{
+  void *handle;
+
+  handle = dlopen (LIBUNWIND_SO, RTLD_NOW);
+  if (handle == NULL)
+    return 0;
+
+  /* Initialize pointers to the dynamic library functions we will use.  */
+
+  unw_get_reg_p = dlsym (handle, get_reg_name);
+  if (unw_get_reg_p == NULL)
+    return 0;
+
+  unw_get_fpreg_p = dlsym (handle, get_fpreg_name);
+  if (unw_get_fpreg_p == NULL)
+    return 0;
+
+  unw_get_saveloc_p = dlsym (handle, get_saveloc_name);
+  if (unw_get_saveloc_p == NULL)
+    return 0;
+
+  unw_step_p = dlsym (handle, step_name);
+  if (unw_step_p == NULL)
+    return 0;
+
+  unw_init_remote_p = dlsym (handle, init_remote_name);
+  if (unw_init_remote_p == NULL)
+    return 0;
+
+  unw_create_addr_space_p = dlsym (handle, create_addr_space_name);
+  if (unw_create_addr_space_p == NULL)
+    return 0;
+
+  unw_search_unwind_table_p = dlsym (handle, search_unwind_table_name);
+  if (unw_search_unwind_table_p == NULL)
+    return 0;
+
+  unw_find_dyn_list_p = dlsym (handle, find_dyn_list_name);
+  if (unw_find_dyn_list_p == NULL)
+    return 0;
+   
+  return 1;
+}
+
+int
+libunwind_is_initialized (void)
+{
+  return libunwind_initialized;
+}
+
+#endif /* HAVE_LIBUNWIND_H  */
+
+/* Provide a prototype to silence -Wmissing-prototypes.  */
+void _initialize_libunwind_frame (void);
+
+void
+_initialize_libunwind_frame (void)
+{
+#ifdef HAVE_LIBUNWIND_H
+  libunwind_initialized = libunwind_load ();
+#endif  
+}
Index: libunwind-frame.h
===================================================================
RCS file: libunwind-frame.h
diff -N libunwind-frame.h
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ libunwind-frame.h	15 Oct 2003 21:13:26 -0000
@@ -0,0 +1,71 @@
+/* Frame unwinder for frames with libunwind frame information.
+
+   Copyright 2003 Free Software Foundation, Inc.
+
+   Contributed by Jeff Johnston.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of 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.
+
+   This program 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 a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#ifdef HAVE_LIBUNWIND_H
+
+#ifndef LIBUNWIND_FRAME_H
+#define LIBUNWIND_FRAME_H 1
+
+#include "libunwind.h"
+
+struct frame_info;
+
+struct libunwind_descr
+{
+  int (*gdb2uw) (int);
+  int (*uw2gdb) (int);
+  int (*is_fpreg) (int);
+  void *accessors;
+};
+
+const struct frame_unwind *
+libunwind_frame_sniffer (struct frame_info *next_frame);
+
+void
+libunwind_set_descr_handle (void *handle);
+
+void
+libunwind_frame_this_id (struct frame_info *next_frame, void **this_cache,
+			 struct frame_id *this_id);
+void
+libunwind_frame_prev_register (struct frame_info *next_frame, void **this_cache,
+			       int regnum, int *optimizedp,
+			       enum lval_type *lvalp, CORE_ADDR *addrp,
+			       int *realnump, void *valuep);
+CORE_ADDR
+libunwind_frame_base_address (struct frame_info *next_frame, void **this_cache);
+
+int
+libunwind_is_initialized (void);
+
+int
+libunwind_search_unwind_table (void *as, long ip, void *di,
+			       void *pi, int need_unwind_info, void *args);
+
+unw_word_t
+libunwind_find_dyn_list (unw_addr_space_t, void *, size_t,
+			 unw_word_t, unw_word_t, void *);
+     
+#endif /* libunwind-frame.h */
+
+#endif /* HAVE_LIBUNWIND_H  */
Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/Makefile.in,v
retrieving revision 1.456
diff -u -r1.456 Makefile.in
--- Makefile.in	11 Oct 2003 15:22:39 -0000	1.456
+++ Makefile.in	15 Oct 2003 21:13:27 -0000
@@ -701,6 +701,7 @@
 jv_lang_h = jv-lang.h
 kod_h = kod.h
 language_h = language.h
+libunwind_frame_h = libunwind-frame.h
 linespec_h = linespec.h
 linux_nat_h = linux-nat.h
 m2_lang_h = m2-lang.h
@@ -890,6 +891,7 @@
 	ui-out.o cli-out.o \
 	varobj.o wrapper.o \
 	jv-lang.o jv-valprint.o jv-typeprint.o \
+	libunwind-frame.o \
 	m2-lang.o p-lang.o p-typeprint.o p-valprint.o \
 	scm-exp.o scm-lang.o scm-valprint.o \
 	sentinel-frame.o \
@@ -1271,6 +1273,7 @@
 	i386gnu-nat.c i386gnu-tdep.c \
 	ia64-linux-nat.c ia64-linux-tdep.c ia64-tdep.c \
 	infptrace.c inftarg.c irix4-nat.c irix5-nat.c \
+	libunwind-frame.c \
 	lynx-nat.c m3-nat.c \
 	m68hc11-tdep.c \
 	m68k-tdep.c \
@@ -1890,7 +1893,7 @@
 	$(arch_utils_h) $(floatformat_h) $(regcache_h) $(reggroups_h) \
 	$(frame_h) $(frame_base_h) $(frame_unwind_h) $(doublest_h) \
 	$(value_h) $(gdb_assert_h) $(objfiles_h) $(elf_common_h) \
-	$(elf_bfd_h) $(dis_asm_h)
+	$(elf_bfd_h) $(dis_asm_h) $(libunwind_frame_h)
 infcall.o: infcall.c $(defs_h) $(breakpoint_h) $(target_h) $(regcache_h) \
 	$(inferior_h) $(gdb_assert_h) $(block_h) $(gdbcore_h) $(language_h) \
 	$(symfile_h) $(gdbcmd_h) $(command_h) $(gdb_string_h) $(infcall_h)
@@ -1938,6 +1941,10 @@
 language.o: language.c $(defs_h) $(gdb_string_h) $(symtab_h) $(gdbtypes_h) \
 	$(value_h) $(gdbcmd_h) $(expression_h) $(language_h) $(target_h) \
 	$(parser_defs_h) $(jv_lang_h) $(demangle_h)
+libunwind-frame.o: libunwind-frame.c $(defs_h) \
+	$(frame_h) $(frame_base_h) $(frame_unwind_h) $(gdbcore_h) \
+	$(gdbtypes_h) $(symtab_h) $(objfiles_h) $(regcache_h) \
+	$(gdb_assert_h) $(gdb_string_h) $(complaints_h) $(libunwind_frame_h)
 linespec.o: linespec.c $(defs_h) $(symtab_h) $(frame_h) $(command_h) \
 	$(symfile_h) $(objfiles_h) $(source_h) $(demangle_h) $(value_h) \
 	$(completer_h) $(cp_abi_h) $(parser_defs_h) $(block_h) \
Index: configure.in
===================================================================
RCS file: /cvs/src/src/gdb/configure.in,v
retrieving revision 1.132
diff -u -r1.132 configure.in
--- configure.in	3 Sep 2003 15:02:48 -0000	1.132
+++ configure.in	15 Oct 2003 21:13:27 -0000
@@ -319,6 +319,8 @@
 AC_HEADER_DIRENT
 AC_HEADER_STAT
 AC_HEADER_STDC
+AC_CHECK_HEADERS(libunwind.h)
+AC_CHECK_HEADERS(libunwind-ia64.h)
 AC_CHECK_HEADERS(link.h)
 AC_CHECK_HEADERS(nlist.h)
 AC_CHECK_HEADERS(poll.h sys/poll.h)