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Re: [patch][python] Add symbol, symbol table and frame block support to GDB API


On 02/04/2010 11:24 PM, Tom Tromey wrote:
>>>>>> "Phil" == Phil Muldoon <pmuldoon@redhat.com> writes:
 

> The code bits look mostly ok to me.  There are a few formatting nits, of
> course ;-), but also a more substantial issue.
> 
> Phil> +typedef struct {
> Phil> +  PyObject_HEAD
> Phil> +  struct block *block;
> Phil> +} block_object;
> 
> When an objfile is destroyed, so are blocks coming from that objfile.
> However, this module doesn't take that into account.  That means it can
> lead to crashes.

Tom,

I've added life-cycle support for symbols, symbol tables, symbol tables
and line, and blocks.  This was a little more involved than I first
thought.  I've also added the other changes you requested


Eli,

I've made that last changes you requested, too.

What do you think?

Cheers,

Phil

--

diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 98f42b9..d0764fd 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -267,23 +267,29 @@ SUBDIR_TUI_CFLAGS= \
 #
 SUBDIR_PYTHON_OBS = \
 	python.o \
+	py-block.o \
 	py-cmd.o \
 	py-frame.o \
 	py-function.o \
 	py-lazy-string.o \
 	py-objfile.o \
 	py-prettyprint.o \
+	py-symbol.o \
+	py-symtab.o \
 	py-type.o \
 	py-utils.o \
 	py-value.o
 SUBDIR_PYTHON_SRCS = \
 	python/python.c \
+	python/py-block.c \
 	python/py-cmd.c \
 	python/py-frame.c \
 	python/py-function.c \
 	python/py-lazy-string.c \
 	python/py-objfile.c \
 	python/py-prettyprint.c \
+	python/py-symbol.c \
+	python/py-symtab.c \
 	python/py-type.c \
 	python/py-utils.c \
 	python/py-value.c
@@ -1970,6 +1976,10 @@ python.o: $(srcdir)/python/python.c
 	$(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/python.c
 	$(POSTCOMPILE)
 
+py-block.o: $(srcdir)/python/py-block.c
+	$(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-block.c
+	$(POSTCOMPILE)
+
 py-cmd.o: $(srcdir)/python/py-cmd.c
 	$(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-cmd.c
 	$(POSTCOMPILE)
@@ -1994,6 +2004,14 @@ py-prettyprint.o: $(srcdir)/python/py-prettyprint.c
 	$(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-prettyprint.c
 	$(POSTCOMPILE)
 
+py-symbol.o: $(srcdir)/python/py-symbol.c
+	$(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-symbol.c
+	$(POSTCOMPILE)
+
+py-symtab.o: $(srcdir)/python/py-symtab.c
+	$(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-symtab.c
+	$(POSTCOMPILE)
+
 py-type.o: $(srcdir)/python/py-type.c
 	$(COMPILE) $(PYTHON_CFLAGS) $(srcdir)/python/py-type.c
 	$(POSTCOMPILE)
diff --git a/gdb/NEWS b/gdb/NEWS
index 867b51f..a7bdec8 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -203,6 +203,11 @@ QTDisconnected
 qTfP, qTsP
    Get data about the tracepoints currently in use.
 
+* Python scripting
+
+The GDB Python API now has access to symbols, symbol tables, and
+frame's code blocks.
+
 * Bug fixes
 
 Process record now works correctly with hardware watchpoints.
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 0e3e093..fdb7ddb 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -19547,7 +19547,10 @@ situation, a Python @code{KeyboardInterrupt} exception is thrown.
 * Commands In Python::          Implementing new commands in Python.
 * Functions In Python::         Writing new convenience functions.
 * Objfiles In Python::          Object files.
-* Frames In Python::            Acessing inferior stack frames from Python.
+* Frames In Python::            Accessing inferior stack frames from Python.
+* Blocks In Python::            Accessing frame blocks from Python.
+* Symbols In Python::           Python representation of symbols.
+* Symbol Tables In Python::     Python representation of symbol tables.
 * Lazy Strings In Python::      Python representation of lazy strings.
 @end menu
 
@@ -20707,7 +20710,7 @@ information.
 @end defivar
 
 @node Frames In Python
-@subsubsection Acessing inferior stack frames from Python.
+@subsubsection Accessing inferior stack frames from Python.
 
 @cindex frames in python
 When the debugged program stops, @value{GDBN} is able to analyze its call
@@ -20770,6 +20773,15 @@ function to a string.
 Returns the frame's resume address.
 @end defmethod
 
+@defmethod Frame block
+Returns the frame's code block.  @xref{Blocks In Python}.
+@end defmethod
+
+@defmethod Frame function
+Returns the symbol for the function corresponding to this frame.
+@xref{Symbols In Python}.
+@end defmethod
+
 @defmethod Frame older
 Return the frame that called this frame.
 @end defmethod
@@ -20778,10 +20790,308 @@ Return the frame that called this frame.
 Return the frame called by this frame.
 @end defmethod
 
+@defmethod Frame find_sal
+Return the frame's symtab and line object.
+@xref{Symbol Tables In Python}.
+@end defmethod
+
 @defmethod Frame read_var variable
 Return the value of the given variable in this frame.  @var{variable} must
 be a string.
 @end defmethod
+
+@defmethod Frame select
+Set this frame to be the selected frame.  @xref{Stack, ,Examining the
+Stack}.
+@end defmethod
+@end table
+
+@node Blocks In Python
+@subsubsection Accessing frame blocks from Python.
+
+@cindex blocks in python
+@tindex gdb.Block
+
+Within each frame, @value{GDBN} maintains information on each block
+stored in that frame.  These blocks are organized hierarchically, and
+are represented individually in Python as a @code{gdb.Block}.
+Please see @ref{Frames In Python} for a more in-depth discussion on
+frames.  Furthermore, see @ref{Stack, ,Examining the Stack} for more
+detailed technical information on @value{GDBN}'s book-keeping of the
+stack.
+
+The following block-related functions are available in the @code{gdb}
+module:
+
+@findex gdb.block_for_pc
+@defun block_for_pc pc
+Return the @code{gdb.Block} containing the given @var{pc} value.  If the
+block cannot be found for the @var{pc} value specified, the function
+will return @code{None}.
+@end defun
+
+A @code{gdb.Block} object has the following attributes:
+
+@table @code
+@defivar Block start
+The start address of the block.  This attribute is not writable.
+@end defivar
+
+@defivar Block end
+The end address of the block.  This attribute is not writable.
+@end defivar
+
+@defivar Block function
+The name of the block represented as a @code{gdb.Symbol}.  If the
+block is not named, then this attribute holds @code{None}.  This
+attribute is not writable.
+@end defivar
+
+@defivar Block superblock
+The block containing this block.  If this parent block does not exist,
+this attribute holds @code{None}.  This attribute is not writable.
+@end defivar
+@end table
+
+@node Symbols In Python
+@subsubsection Python representation of Symbols.
+
+@cindex symbols in python
+@tindex gdb.Symbol
+
+@value{GDBN} represents every variable, function and type as an
+entry in a symbol table.  @xref{Symbols, ,Examining the Symbol Table}.
+Similarly, Python represents these symbols in @value{GDBN} with the
+@code{gdb.Symbol} object.
+
+The following symbol-related functions are available in the @code{gdb}
+module:
+
+@findex gdb.lookup_symbol
+@defun lookup_symbol name [block] [domain]
+This function searches for a symbol by name.  The search scope can be
+restricted to the parameters defined in the optional domain and block
+arguments.
+
+@var{name} is the name of the symbol.  It must be a string.  The
+optional @var{block} argument restricts the search to symbols visible
+in that @var{block}.  The @var{block} argument must be a
+@code{gdb.Block} object.  The optional @var{domain} argument restricts
+the search to the domain type.  The @var{domain} argument must be a
+domain constant defined in the @code{gdb} module and described later
+in this chapter.
+@end defun
+
+A @code{gdb.Symbol} object has the following attributes:
+
+@table @code
+@defivar Symbol symtab
+The symbol table in which the symbol appears.  This attribute is
+represented as a @code{gdb.Symtab} object.  @xref{Symbol Tables In
+Python}.  This attribute is not writable.
+@end defivar
+
+@defivar Symbol name
+The name of the symbol as a string.  This attribute is not writable.
+@end defivar
+
+@defivar Symbol linkage_name
+The name of the symbol, as used by the linker (i.e., may be mangled).
+This attribute is not writable.
+@end defivar
+
+@defivar Symbol print_name
+The name of the symbol in a form suitable for output.  This is either
+@code{name} or @code{linkage_name}, depending on whether the user
+asked @value{GDBN} to display demangled or mangled names.
+@end defivar
+
+@defivar Symbol addr_class
+The address class of the symbol.  This classifies how to find the value
+of a symbol.  Each address class is a constant defined in the
+@code{gdb} module and described later in this chapter.
+@end defivar
+
+@defivar Symbol is_argument
+@code{True} if the symbol is an argument of a function.
+@end defivar
+
+@defivar Symbol is_constant
+@code{True} if the symbol is a constant.
+@end defivar
+
+@defivar Symbol is_function
+@code{True} if the symbol is a function or a method.
+@end defivar
+
+@defivar Symbol is_variable
+@code{True} if the symbol is a variable.
+@end defivar
+@end table
+
+The available domain categories in @code{gdb.Symbol} are represented
+as constants in the @code{gdb} module:
+
+@table @code
+@findex SYMBOL_UNDEF_DOMAIN
+@findex gdb.SYMBOL_UNDEF_DOMAIN
+@item SYMBOL_UNDEF_DOMAIN
+This is used when a domain has not been discovered or none of the
+following domains apply.  This usually indicates an error either
+in the symbol information or in @value{GDBN}'s handling of symbols.
+@findex SYMBOL_VAR_DOMAIN
+@findex gdb.SYMBOL_VAR_DOMAIN
+@item SYMBOL_VAR_DOMAIN
+This domain contains variables, function names, typedef names and enum
+type values.
+@findex SYMBOL_STRUCT_DOMAIN
+@findex gdb.SYMBOL_STRUCT_DOMAIN
+@item SYMBOL_STRUCT_DOMAIN
+This domain holds struct, union and enum type names.
+@findex SYMBOL_LABEL_DOMAIN
+@findex gdb.SYMBOL_LABEL_DOMAIN
+@item SYMBOL_LABEL_DOMAIN
+This domain contains names of labels (for gotos).
+@findex SYMBOL_VARIABLES_DOMAIN
+@findex gdb.SYMBOL_VARIABLES_DOMAIN
+@item SYMBOL_VARIABLES_DOMAIN
+This domain holds a subset of the @code{SYMBOLS_VAR_DOMAIN}; it
+contains everything minus functions and types.
+@findex SYMBOL_FUNCTIONS_DOMAIN
+@findex gdb.SYMBOL_FUNCTIONS_DOMAIN
+@item SYMBOL_FUNCTION_DOMAIN
+This domain contains all functions.
+@findex SYMBOL_TYPES_DOMAIN
+@findex gdb.SYMBOL_TYPES_DOMAIN
+@item SYMBOL_TYPES_DOMAIN
+This domain contains all types.
+@end table
+
+The available address class categories in @code{gdb.Symbol} are represented
+as constants in the @code{gdb} module:
+
+@table @code
+@findex SYMBOL_LOC_UNDEF
+@findex gdb.SYMBOL_LOC_UNDEF
+@item SYMBOL_LOC_UNDEF
+If this is returned by address class, it indicates an error either in
+the symbol information or in @value{GDBN}'s handling of symbols.
+@findex SYMBOL_LOC_CONST
+@findex gdb.SYMBOL_LOC_CONST
+@item SYMBOL_LOC_CONST
+Value is constant int.
+@findex SYMBOL_LOC_STATIC
+@findex gdb.SYMBOL_LOC_STATIC
+@item SYMBOL_LOC_STATIC
+Value is at a fixed address.
+@findex SYMBOL_LOC_REGISTER
+@findex gdb.SYMBOL_LOC_REGISTER
+@item SYMBOL_LOC_REGISTER
+Value is in a register.
+@findex SYMBOL_LOC_ARG
+@findex gdb.SYMBOL_LOC_ARG
+@item SYMBOL_LOC_ARG
+Value is an argument.  This value is at the offset stored within the
+symbol inside the frame's argument list.
+@findex SYMBOL_LOC_REF_ARG
+@findex gdb.SYMBOL_LOC_REF_ARG
+@item SYMBOL_LOC_REF_ARG
+Value address is stored in the frame's argument list.  Just like
+@code{LOC_ARG} except that the value's address is stored at the
+offset, not the value itself.
+@findex SYMBOL_LOC_REGPARM_ADDR
+@findex gdb.SYMBOL_LOC_REGPARM_ADDR
+@item SYMBOL_LOC_REGPARM_ADDR
+Value is a specified register.  Just like @code{LOC_REGISTER} except
+the register holds the address of the argument instead of the argument
+itself.
+@findex SYMBOL_LOC_LOCAL
+@findex gdb.SYMBOL_LOC_LOCAL
+@item SYMBOL_LOC_LOCAL
+Value is a local variable.
+@findex SYMBOL_LOC_TYPEDEF
+@findex gdb.SYMBOL_LOC_TYPEDEF
+@item SYMBOL_LOC_TYPEDEF
+Value not used.  Symbols in the domain @code{SYMBOL_STRUCT_DOMAIN} all
+have this class.
+@findex SYMBOL_LOC_BLOCK
+@findex gdb.SYMBOL_LOC_BLOCK
+@item SYMBOL_LOC_BLOCK
+Value is a block.
+@findex SYMBOL_LOC_CONST_BYTES
+@findex gdb.SYMBOL_LOC_CONST_BYTES
+@item SYMBOL_LOC_CONST_BYTES
+Value is a byte-sequence.
+@findex SYMBOL_LOC_UNRESOLVED
+@findex gdb.SYMBOL_LOC_UNRESOLVED
+@item SYMBOL_LOC_UNRESOLVED
+Value is at a fixed address, but the address of the variable has to be
+determined from the minimal symbol table whenever the variable is
+referenced.
+@findex SYMBOL_LOC_OPTIMIZED_OUT
+@findex gdb.SYMBOL_LOC_OPTIMIZED_OUT
+@item SYMBOL_LOC_OPTIMIZED_OUT
+The value does not actually exist in the program.
+@findex SYMBOL_LOC_COMPUTED
+@findex gdb.SYMBOL_LOC_COMPUTED
+@item SYMBOL_LOC_COMPUTED
+The value's address is a computed location.
+@end table
+
+@node Symbol Tables In Python
+@subsubsection Symbol table representation in Python.
+
+@cindex symbol tables in python
+@tindex gdb.Symtab
+@tindex gdb.Symtab_and_line
+
+Access to symbol table data maintained by @value{GDBN} on the inferior
+is exposed to Python via two objects: @code{gdb.Symtab_and_line} and
+@code{gdb.Symtab}.  Symbol table and line data for a frame is returned
+from the @code{find_sal} method in @code{gdb.Frame} object.
+@xref{Frames In Python}.
+
+For more information on @value{GDBN}'s symbol table management, see
+@ref{Symbols, ,Examining the Symbol Table} for more information.
+
+A @code{gdb.Symtab_and_line} object has the following attributes:
+
+@table @code
+@defivar Symtab_and_line symtab
+The symbol table object (@code{gdb.Symtab}) for this frame.
+This attribute is not writable.
+@end defivar
+
+@defivar Symtab_and_line pc
+Indicates the current program counter address.  This attribute is not
+writable.
+@end defivar
+
+@defivar Symtab_and_line line
+Indicates the current line number for this object.  This
+attribute is not writable.
+@end defivar
+@end table
+
+A @code{gdb.Symtab} object has the following attributes:
+
+@table @code
+@defivar Symtab filename
+The symbol table's source filename.  This attribute is not writable.
+@end defivar
+
+@defivar Symtab objfile
+The symbol table's backing object file.  @xref{Objfiles In Python}.
+This attribute is not writable.
+@end defivar
+@end table
+
+The following methods are provided:
+
+@table @code
+@defmethod Symtab fullname
+Return the symbol table's source absolute file name.
+@end defmethod
 @end table
 
 @node Lazy Strings In Python
diff --git a/gdb/python/py-block.c b/gdb/python/py-block.c
new file mode 100644
index 0000000..6f15e3b
--- /dev/null
+++ b/gdb/python/py-block.c
@@ -0,0 +1,441 @@
+/* Python interface to blocks.
+
+   Copyright (C) 2008, 2009, 2010 Free Software Foundation, Inc.
+
+   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 3 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, see <http://www.gnu.org/licenses/>.  */
+
+#include "defs.h"
+#include "block.h"
+#include "dictionary.h"
+#include "symtab.h"
+#include "python-internal.h"
+#include "exceptions.h"
+#include "objfiles.h"
+#include "symtab.h"
+
+typedef struct blpy_block_object {
+  PyObject_HEAD
+  /* The GDB block structure that represents a frame's code block.  */
+  struct block *block;
+  /* The backing object file.  There is no direct relationship in GDB
+     between a block and an object file.  When a block is created also
+     store a pointer to the object file for later use.  */
+  struct objfile *objfile;
+  /* Keep track of all blocks with a doubly-linked list.  Needed for
+     block invalidation if the source object file has been freed.  */
+  struct blpy_block_object *prev;
+  struct blpy_block_object *next;
+} block_object;
+
+typedef struct {
+  PyObject_HEAD
+  /* The block dictionary of symbols.  */
+  struct dictionary *dict;
+  /* The iterator for that dictionary.  */
+  struct dict_iterator iter;
+  /* Has the iterator been initialized flag.  */
+  int initialized_p;
+  /* Pointer back to the original source block object.  Needed to
+     check if the block is still valid, and has not been invalidated
+     when an object file has been freed.  */
+  struct blpy_block_object *source;
+} block_syms_iterator_object;
+
+/* Require a valid block.  All access to block_object->block should be
+   gated by this call.  This must be called inside a TRY_CATCH, or
+   another context in which a gdb exception is allowed.  */
+#define BLPY_REQUIRE_VALID(block_obj, block)		\
+  do {							\
+      block = block_object_to_block (block_obj);	\
+      if (block == NULL)			        \
+	error (_("Block is invalid."));			\
+    } while (0)
+
+/* Require a valid block.  This macro is called during block iterator
+   creation, and at each next call.  This must be called inside a
+   TRY_CATCH, or another context in which a gdb exception is
+   allowed.  */
+#define BLPY_ITER_REQUIRE_VALID(block_obj)		    \
+  do {							    \
+      if (block_obj->block == NULL)			    \
+	error (_("Source block for iterator is invalid.")); \
+    } while (0)
+
+static PyTypeObject block_syms_iterator_object_type;
+static const struct objfile_data *blpy_objfile_data_key;
+
+static PyObject *
+blpy_iter (PyObject *self)
+{
+  block_syms_iterator_object *block_iter_obj;
+  struct block *block = NULL;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      BLPY_REQUIRE_VALID (self, block);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  block_iter_obj = PyObject_New (block_syms_iterator_object,
+				 &block_syms_iterator_object_type);
+  if (block_iter_obj == NULL)
+      return NULL;
+
+  block_iter_obj->dict = BLOCK_DICT (block);
+  block_iter_obj->initialized_p = 0;
+  Py_INCREF (self);
+  block_iter_obj->source = (block_object *) self;
+
+  return (PyObject *) block_iter_obj;
+}
+
+static PyObject *
+blpy_get_start (PyObject *self, void *closure)
+{
+  struct block *block = NULL;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      BLPY_REQUIRE_VALID (self, block);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  return PyLong_FromUnsignedLongLong (BLOCK_START (block));
+}
+
+static PyObject *
+blpy_get_end (PyObject *self, void *closure)
+{
+  struct block *block = NULL;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      BLPY_REQUIRE_VALID (self, block);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  return PyLong_FromUnsignedLongLong (BLOCK_END (block));
+}
+
+static PyObject *
+blpy_get_function (PyObject *self, void *closure)
+{
+  struct symbol *sym;
+  struct block *block = NULL;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      BLPY_REQUIRE_VALID (self, block);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  sym = BLOCK_FUNCTION (block);
+  if (sym)
+    return symbol_to_symbol_object (sym);
+
+  Py_RETURN_NONE;
+}
+
+static PyObject *
+blpy_get_superblock (PyObject *self, void *closure)
+{
+  struct block *block = NULL;
+  struct block *super_block = NULL;
+  block_object *self_obj  = (block_object *) self;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      BLPY_REQUIRE_VALID (self, block);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  super_block = BLOCK_SUPERBLOCK (block);
+  if (super_block)
+    return block_to_block_object (super_block, self_obj->objfile);
+
+  Py_RETURN_NONE;
+}
+
+static void
+blpy_dealloc (PyObject *obj)
+{
+  block_object *block = (block_object *) obj;
+
+  if (block->prev)
+    block->prev->next = block->next;
+  else if (block->objfile)
+    {
+      set_objfile_data (block->objfile, blpy_objfile_data_key, block->next);
+    }
+  if (block->next)
+    block->next->prev = block->prev;
+  block->block = NULL;
+}
+
+/* Given a block, and a block_object that has previously been
+   allocated and initialized, populate the block_object with the
+   struct block data.  Also, register the block_object life-cycle
+   with the life-cycle of the the object file associated with this
+   block, if needed.  */
+static void
+set_block (block_object *obj, struct block *block,
+	   struct objfile *objfile)
+{
+  obj->block = block;
+  obj->prev = NULL;
+  if (objfile)
+    {
+      obj->objfile = objfile;
+      obj->next = objfile_data (objfile, blpy_objfile_data_key);
+      if (obj->next)
+	obj->next->prev = obj;
+      set_objfile_data (objfile, blpy_objfile_data_key, obj);
+    }
+  else
+    obj->next = NULL;
+}
+
+/* Create a new block object (gdb.Block) that encapsulates the struct
+   block object from GDB.  */
+PyObject *
+block_to_block_object (struct block *block, struct objfile *objfile)
+{
+  block_object *block_obj;
+
+  block_obj = PyObject_New (block_object, &block_object_type);
+  if (block_obj)
+    set_block (block_obj, block, objfile);
+
+  return (PyObject *) block_obj;
+}
+
+/* Return struct block reference that is wrapped by this object.  */
+struct block *
+block_object_to_block (PyObject *obj)
+{
+  if (! PyObject_TypeCheck (obj, &block_object_type))
+    return NULL;
+  return ((block_object *) obj)->block;
+}
+
+/* Return a reference to the block iterator.  */
+static PyObject *
+blpy_block_syms_iter (PyObject *self)
+{
+  block_syms_iterator_object *iter_obj = (block_syms_iterator_object *) self;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      BLPY_ITER_REQUIRE_VALID (iter_obj->source);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  Py_INCREF (self);
+  return self;
+}
+
+/* Return the next symbol in the iteration through the block's
+   dictionary.  */
+static PyObject *
+blpy_block_syms_iternext (PyObject *self)
+{
+  block_syms_iterator_object *iter_obj = (block_syms_iterator_object *) self;
+  struct symbol *sym;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      BLPY_ITER_REQUIRE_VALID (iter_obj->source);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  if (!iter_obj->initialized_p)
+    {
+      sym = dict_iterator_first (iter_obj->dict,  &(iter_obj->iter));
+      iter_obj->initialized_p = 1;
+    }
+  else
+    sym = dict_iterator_next (&(iter_obj->iter));
+
+  return (sym == NULL) ? NULL : symbol_to_symbol_object (sym);
+}
+
+static void
+blpy_block_syms_dealloc (PyObject *obj)
+{
+  block_syms_iterator_object *iter_obj = (block_syms_iterator_object *) obj;
+  Py_XDECREF (iter_obj->source);
+}
+
+/* Return the innermost lexical block containing the specified pc value,
+   or 0 if there is none.  */
+PyObject *
+gdbpy_block_for_pc (PyObject *self, PyObject *args)
+{
+  unsigned PY_LONG_LONG pc;
+  struct block *block;
+  struct obj_section *section;
+  struct symtab *symtab;
+  PyObject *sym_obj;
+
+  if (!PyArg_ParseTuple (args, "K", &pc))
+    return NULL;
+
+  section = find_pc_mapped_section (pc);
+  symtab = find_pc_sect_symtab (pc, section);
+  if (!symtab || symtab->objfile == NULL)
+    {
+      PyErr_SetString (PyExc_RuntimeError, "Cannot locate object file for block.");
+      return NULL;
+    }
+
+  block = block_for_pc (pc);
+  if (block)
+    return block_to_block_object (block, symtab->objfile);
+
+  Py_RETURN_NONE;
+}
+
+/* This function is called when an objfile is about to be freed.
+   Invalidate the block as further actions on the block would result
+   in bad data.  All access to obj->symbol should be gated by
+   BLPY_REQUIRE_VALID which will raise an exception on invalid
+   blocks.  */
+static void
+del_objfile_blocks (struct objfile *objfile, void *datum)
+{
+  block_object *obj = datum;
+  while (obj)
+    {
+      block_object *next = obj->next;
+
+      obj->block = NULL;
+      obj->objfile = NULL;
+      obj->next = NULL;
+      obj->prev = NULL;
+
+      obj = next;
+    }
+}
+
+void
+gdbpy_initialize_blocks (void)
+{
+  block_object_type.tp_new = PyType_GenericNew;
+  if (PyType_Ready (&block_object_type) < 0)
+    return;
+
+  block_syms_iterator_object_type.tp_new = PyType_GenericNew;
+  if (PyType_Ready (&block_syms_iterator_object_type) < 0)
+    return;
+
+  /* Register an objfile "free" callback so we can properly
+     invalidate blocks when an object file is about to be
+     deleted.  */
+  blpy_objfile_data_key
+    = register_objfile_data_with_cleanup (NULL, del_objfile_blocks);
+
+  Py_INCREF (&block_object_type);
+  PyModule_AddObject (gdb_module, "Block", (PyObject *) &block_object_type);
+
+  Py_INCREF (&block_syms_iterator_object_type);
+  PyModule_AddObject (gdb_module, "BlockIterator",
+		      (PyObject *) &block_syms_iterator_object_type);
+}
+
+
+
+static PyGetSetDef block_object_getset[] = {
+  { "start", blpy_get_start, NULL, "Start address of the block.", NULL },
+  { "end", blpy_get_end, NULL, "End address of the block.", NULL },
+  { "function", blpy_get_function, NULL,
+    "Symbol that names the block, or None.", NULL },
+  { "superblock", blpy_get_superblock, NULL,
+    "Block containing the block, or None.", NULL },
+  { NULL }  /* Sentinel */
+};
+
+PyTypeObject block_object_type = {
+  PyObject_HEAD_INIT (NULL)
+  0,				  /*ob_size*/
+  "gdb.Block",			  /*tp_name*/
+  sizeof (block_object),	  /*tp_basicsize*/
+  0,				  /*tp_itemsize*/
+  blpy_dealloc,                   /*tp_dealloc*/
+  0,				  /*tp_print*/
+  0,				  /*tp_getattr*/
+  0,				  /*tp_setattr*/
+  0,				  /*tp_compare*/
+  0,				  /*tp_repr*/
+  0,				  /*tp_as_number*/
+  0,				  /*tp_as_sequence*/
+  0,				  /*tp_as_mapping*/
+  0,				  /*tp_hash */
+  0,				  /*tp_call*/
+  0,				  /*tp_str*/
+  0,				  /*tp_getattro*/
+  0,				  /*tp_setattro*/
+  0,				  /*tp_as_buffer*/
+  Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER,  /*tp_flags*/
+  "GDB block object",		  /* tp_doc */
+  0,				  /* tp_traverse */
+  0,				  /* tp_clear */
+  0,				  /* tp_richcompare */
+  0,				  /* tp_weaklistoffset */
+  blpy_iter,			  /* tp_iter */
+  0,				  /* tp_iternext */
+  0,				  /* tp_methods */
+  0,				  /* tp_members */
+  block_object_getset		  /* tp_getset */
+};
+
+static PyTypeObject block_syms_iterator_object_type = {
+  PyObject_HEAD_INIT (NULL)
+  0,				  /*ob_size*/
+  "gdb.BlockIterator",		  /*tp_name*/
+  sizeof (block_syms_iterator_object),	      /*tp_basicsize*/
+  0,				  /*tp_itemsize*/
+  blpy_block_syms_dealloc,	  /*tp_dealloc*/
+  0,				  /*tp_print*/
+  0,				  /*tp_getattr*/
+  0,				  /*tp_setattr*/
+  0,				  /*tp_compare*/
+  0,				  /*tp_repr*/
+  0,				  /*tp_as_number*/
+  0,				  /*tp_as_sequence*/
+  0,				  /*tp_as_mapping*/
+  0,				  /*tp_hash */
+  0,				  /*tp_call*/
+  0,				  /*tp_str*/
+  0,				  /*tp_getattro*/
+  0,				  /*tp_setattro*/
+  0,				  /*tp_as_buffer*/
+  Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_ITER,  /*tp_flags*/
+  "GDB block syms iterator object",	      /*tp_doc */
+  0,				  /*tp_traverse */
+  0,				  /*tp_clear */
+  0,				  /*tp_richcompare */
+  0,				  /*tp_weaklistoffset */
+  blpy_block_syms_iter,           /*tp_iter */
+  blpy_block_syms_iternext,	  /*tp_iternext */
+  0				  /*tp_methods */
+};
diff --git a/gdb/python/py-frame.c b/gdb/python/py-frame.c
index 334bad9..bb892bd 100644
--- a/gdb/python/py-frame.c
+++ b/gdb/python/py-frame.c
@@ -26,6 +26,8 @@
 #include "stack.h"
 #include "value.h"
 #include "python-internal.h"
+#include "symfile.h"
+#include "objfiles.h"
 
 typedef struct {
   PyObject_HEAD
@@ -202,6 +204,63 @@ frapy_pc (PyObject *self, PyObject *args)
   return PyLong_FromUnsignedLongLong (pc);
 }
 
+/* Implementation of gdb.Frame.block (self) -> gdb.Block.
+   Returns the frame's code block.  */
+
+static PyObject *
+frapy_block (PyObject *self, PyObject *args)
+{
+  struct frame_info *frame;
+  struct block *block = NULL;
+  volatile struct gdb_exception except;
+  struct symtab_and_line sal;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      FRAPY_REQUIRE_VALID ((frame_object *) self, frame);
+
+      find_frame_sal (frame, &sal);
+      block = block_for_pc (get_frame_address_in_block (frame));
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  if (!sal.symtab || !sal.symtab->objfile)
+    {
+      PyErr_SetString (PyExc_RuntimeError, "Cannot locate object file for block.");
+      return NULL;
+    }
+
+  if (block)
+    return block_to_block_object (block, sal.symtab->objfile);
+
+  Py_RETURN_NONE;
+}
+
+
+/* Implementation of gdb.Frame.function (self) -> gdb.Symbol.
+   Returns the symbol for the function corresponding to this frame.  */
+
+static PyObject *
+frapy_function (PyObject *self, PyObject *args)
+{
+  struct symbol *sym = NULL;
+  struct frame_info *frame;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      FRAPY_REQUIRE_VALID ((frame_object *) self, frame);
+
+      sym = find_pc_function (get_frame_address_in_block (frame));
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  if (sym)
+    return symbol_to_symbol_object (sym);
+
+  Py_RETURN_NONE;
+}
+
 /* Convert a frame_info struct to a Python Frame object.
    Sets a Python exception and returns NULL on error.  */
 
@@ -296,6 +355,30 @@ frapy_newer (PyObject *self, PyObject *args)
   return next_obj;
 }
 
+/* Implementation of gdb.Frame.find_sal (self) -> gdb.Symtab_and_line.
+   Returns the frame's symtab and line.  */
+
+static PyObject *
+frapy_find_sal (PyObject *self, PyObject *args)
+{
+  struct frame_info *frame;
+  struct symtab_and_line sal;
+  struct objfile *objfile = NULL;
+  volatile struct gdb_exception except;
+  PyObject *sal_obj = NULL;   /* Initialize to appease gcc warning.  */
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      FRAPY_REQUIRE_VALID ((frame_object *) self, frame);
+
+      find_frame_sal (frame, &sal);
+      sal_obj = symtab_and_line_to_sal_object (sal);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  return sal_obj;
+}
+
 /* Implementation of gdb.Frame.read_var_value (self, variable) -> gdb.Value.
    Returns the value of the given variable in this frame.  The argument must be
    a string.  Returns None if GDB can't find the specified variable.  */
@@ -312,7 +395,9 @@ frapy_read_var (PyObject *self, PyObject *args)
   if (!PyArg_ParseTuple (args, "O", &sym_obj))
     return NULL;
 
-  if (gdbpy_is_string (sym_obj))
+  if (PyObject_TypeCheck (sym_obj, &symbol_object_type))
+    var = symbol_object_to_symbol (sym_obj);
+  else if (gdbpy_is_string (sym_obj))
     {
       char *var_name;
       struct block *block = NULL;
@@ -365,6 +450,26 @@ frapy_read_var (PyObject *self, PyObject *args)
   Py_RETURN_NONE;
 }
 
+/* Select this frame.  */
+
+static PyObject *
+frapy_select (PyObject *self, PyObject *args)
+{
+  struct frame_info *fi;
+  frame_object *frame = (frame_object *) self;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      FRAPY_REQUIRE_VALID (frame, fi);
+
+      select_frame (fi);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  Py_RETURN_NONE;
+}
+
 /* Implementation of gdb.selected_frame () -> gdb.Frame.
    Returns the selected frame object.  */
 
@@ -484,15 +589,26 @@ Return the reason why it's not possible to find frames older than this." },
   { "pc", frapy_pc, METH_NOARGS,
     "pc () -> Long.\n\
 Return the frame's resume address." },
+  { "block", frapy_block, METH_NOARGS,
+    "block () -> gdb.Block.\n\
+Return the frame's code block." },
+  { "function", frapy_function, METH_NOARGS,
+    "function () -> gdb.Symbol.\n\
+Returns the symbol for the function corresponding to this frame." },
   { "older", frapy_older, METH_NOARGS,
     "older () -> gdb.Frame.\n\
 Return the frame that called this frame." },
   { "newer", frapy_newer, METH_NOARGS,
     "newer () -> gdb.Frame.\n\
 Return the frame called by this frame." },
+  { "find_sal", frapy_find_sal, METH_NOARGS,
+    "find_sal () -> gdb.Symtab_and_line.\n\
+Return the frame's symtab and line." },
   { "read_var", frapy_read_var, METH_VARARGS,
     "read_var (variable) -> gdb.Value.\n\
 Return the value of the variable in this frame." },
+  { "select", frapy_select, METH_NOARGS,
+    "Select this frame as the user's current frame." },
   {NULL}  /* Sentinel */
 };
 
diff --git a/gdb/python/py-symbol.c b/gdb/python/py-symbol.c
new file mode 100644
index 0000000..28d3d5d
--- /dev/null
+++ b/gdb/python/py-symbol.c
@@ -0,0 +1,467 @@
+/* Python interface to symbols.
+
+   Copyright (C) 2008, 2009, 2010 Free Software Foundation, Inc.
+
+   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 3 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, see <http://www.gnu.org/licenses/>.  */
+
+#include "defs.h"
+#include "block.h"
+#include "exceptions.h"
+#include "frame.h"
+#include "symtab.h"
+#include "python-internal.h"
+#include "objfiles.h"
+
+typedef struct sympy_symbol_object {
+  PyObject_HEAD
+  /* The GDB symbol structure this object is wrapping.  */
+  struct symbol *symbol;
+  /* A symbol object is associated with an objfile, so keep track with
+     doubly-linked list, rooted in the objfile.  This lets us
+     invalidate the underlying struct symbol when the objfile is
+     deleted.  */
+  struct sympy_symbol_object *prev;
+  struct sympy_symbol_object *next;
+} symbol_object;
+
+/* Require a valid symbol.  All access to symbol_object->symbol should be
+   gated by this call.  This must be called inside a TRY_CATCH, or
+   another context in which a gdb exception is allowed.  */
+#define SYMPY_REQUIRE_VALID(symbol_obj, symbol)		\
+  do {							\
+      symbol = symbol_object_to_symbol (symbol_obj);	\
+      if (symbol == NULL)			        \
+	error (_("Symbol is invalid."));		\
+    } while (0)
+
+static const struct objfile_data *sympy_objfile_data_key;
+
+static PyObject *
+sympy_str (PyObject *self)
+{
+  char *s;
+  PyObject *result;
+  struct symbol *symbol = NULL;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      SYMPY_REQUIRE_VALID (self, symbol);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  s = xstrprintf ("symbol for %s",
+		  SYMBOL_PRINT_NAME (symbol));
+
+  result = PyString_FromString (s);
+  xfree (s);
+
+  return result;
+}
+
+static PyObject *
+sympy_get_symtab (PyObject *self, void *closure)
+{
+  struct symbol *symbol = NULL;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      SYMPY_REQUIRE_VALID (self, symbol);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  return symtab_to_symtab_object (SYMBOL_SYMTAB (symbol));
+}
+
+static PyObject *
+sympy_get_name (PyObject *self, void *closure)
+{
+  struct symbol *symbol = NULL;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      SYMPY_REQUIRE_VALID (self, symbol);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  return PyString_FromString (SYMBOL_NATURAL_NAME (symbol));
+}
+
+static PyObject *
+sympy_get_linkage_name (PyObject *self, void *closure)
+{
+  struct symbol *symbol = NULL;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      SYMPY_REQUIRE_VALID (self, symbol);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  return PyString_FromString (SYMBOL_LINKAGE_NAME (symbol));
+}
+
+static PyObject *
+sympy_get_print_name (PyObject *self, void *closure)
+{
+  struct symbol *symbol = NULL;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      SYMPY_REQUIRE_VALID (self, symbol);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  return PyString_FromString (SYMBOL_PRINT_NAME (symbol));
+}
+
+static PyObject *
+sympy_get_addr_class (PyObject *self, void *closure)
+{
+  struct symbol *symbol = NULL;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      SYMPY_REQUIRE_VALID (self, symbol);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  return PyInt_FromLong (SYMBOL_CLASS (symbol));
+}
+
+static PyObject *
+sympy_is_argument (PyObject *self, void *closure)
+{
+  struct symbol *symbol = NULL;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      SYMPY_REQUIRE_VALID (self, symbol);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  return PyBool_FromLong (SYMBOL_IS_ARGUMENT (symbol));
+}
+
+static PyObject *
+sympy_is_constant (PyObject *self, void *closure)
+{
+  struct symbol *symbol = NULL;
+  volatile struct gdb_exception except;
+  enum address_class class;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      SYMPY_REQUIRE_VALID (self, symbol);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  class = SYMBOL_CLASS (symbol);
+
+  return PyBool_FromLong (class == LOC_CONST || class == LOC_CONST_BYTES);
+}
+
+static PyObject *
+sympy_is_function (PyObject *self, void *closure)
+{
+  struct symbol *symbol = NULL;
+  volatile struct gdb_exception except;
+  enum address_class class;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      SYMPY_REQUIRE_VALID (self, symbol);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  class = SYMBOL_CLASS (symbol);
+
+  return PyBool_FromLong (class == LOC_BLOCK);
+}
+
+static PyObject *
+sympy_is_variable (PyObject *self, void *closure)
+{
+  struct symbol *symbol = NULL;
+  volatile struct gdb_exception except;
+  enum address_class class;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      SYMPY_REQUIRE_VALID (self, symbol);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  class = SYMBOL_CLASS (symbol);
+
+  return PyBool_FromLong (!SYMBOL_IS_ARGUMENT (symbol)
+			  && (class == LOC_LOCAL || class == LOC_REGISTER
+			      || class == LOC_STATIC || class == LOC_COMPUTED
+			      || class == LOC_OPTIMIZED_OUT));
+}
+
+/* Given a symbol, and a symbol_object that has previously been
+   allocated and initialized, populate the symbol_object with the
+   struct symbol data.  Also, register the symbol_object life-cycle
+   with the life-cycle of the the object file associated with this
+   symbol, if needed.  */
+static void
+set_symbol (symbol_object *obj, struct symbol *symbol)
+{
+  obj->symbol = symbol;
+  obj->prev = NULL;
+  if (symbol->symtab)
+    {
+      obj->next = objfile_data (symbol->symtab->objfile, sympy_objfile_data_key);
+      if (obj->next)
+	obj->next->prev = obj;
+      set_objfile_data (symbol->symtab->objfile, sympy_objfile_data_key, obj);
+    }
+  else
+    obj->next = NULL;
+}
+
+/* Create a new symbol object (gdb.Symbol) that encapsulates the struct
+   symbol object from GDB.  */
+PyObject *
+symbol_to_symbol_object (struct symbol *sym)
+{
+  symbol_object *sym_obj;
+
+  sym_obj = PyObject_New (symbol_object, &symbol_object_type);
+  if (sym_obj)
+    set_symbol (sym_obj, sym);
+
+  return (PyObject *) sym_obj;
+}
+
+/* Return the symbol that is wrapped by this symbol object.  */
+struct symbol *
+symbol_object_to_symbol (PyObject *obj)
+{
+  if (! PyObject_TypeCheck (obj, &symbol_object_type))
+    return NULL;
+  return ((symbol_object *) obj)->symbol;
+}
+
+static void
+sympy_dealloc (PyObject *obj)
+{
+  symbol_object *sym_obj = (symbol_object *) obj;
+
+  if (sym_obj->prev)
+    sym_obj->prev->next = sym_obj->next;
+  else if (sym_obj->symbol->symtab)
+    {
+      set_objfile_data (sym_obj->symbol->symtab->objfile, sympy_objfile_data_key, sym_obj->next);
+    }
+  if (sym_obj->next)
+    sym_obj->next->prev = sym_obj->prev;
+  sym_obj->symbol = NULL;
+}
+
+/* Implementation of
+   gdb.lookup_symbol (name [, block] [, domain]) -> (symbol, is_field_of_this)
+   A tuple with 2 elements is always returned.  The first is the symbol
+   object or None, the second is a boolean with the value of
+   is_a_field_of_this (see comment in lookup_symbol_in_language).  */
+PyObject *
+gdbpy_lookup_symbol (PyObject *self, PyObject *args, PyObject *kw)
+{
+  int domain = VAR_DOMAIN, is_a_field_of_this = 0;
+  const char *name;
+  static char *keywords[] = { "name", "block", "domain", NULL };
+  struct symbol *symbol;
+  PyObject *block_obj = NULL, *ret_tuple, *sym_obj, *bool_obj;
+  struct block *block = NULL;
+
+  if (! PyArg_ParseTupleAndKeywords (args, kw, "s|O!i", keywords, &name,
+				     &block_object_type, &block_obj, &domain))
+    return NULL;
+
+  if (block_obj)
+    block = block_object_to_block (block_obj);
+  else
+    {
+      struct frame_info *selected_frame;
+      volatile struct gdb_exception except;
+
+      TRY_CATCH (except, RETURN_MASK_ALL)
+	{
+	  selected_frame  = get_selected_frame (_("No frame selected."));
+	  block = block_for_pc (get_frame_address_in_block (selected_frame));
+	}
+      GDB_PY_HANDLE_EXCEPTION (except);
+    }
+
+  symbol = lookup_symbol (name, block, domain, &is_a_field_of_this);
+
+  ret_tuple = PyTuple_New (2);
+  if (!ret_tuple)
+    return NULL;
+
+  if (symbol)
+    {
+      sym_obj = symbol_to_symbol_object (symbol);
+      if (!sym_obj)
+	{
+	  Py_DECREF (ret_tuple);
+	  return NULL;
+	}
+    }
+  else
+    {
+      sym_obj = Py_None;
+      Py_INCREF (Py_None);
+    }
+  PyTuple_SET_ITEM (ret_tuple, 0, sym_obj);
+
+  bool_obj = is_a_field_of_this? Py_True : Py_False;
+  Py_INCREF (bool_obj);
+  PyTuple_SET_ITEM (ret_tuple, 1, bool_obj);
+
+  return ret_tuple;
+}
+
+/* This function is called when an objfile is about to be freed.
+   Invalidate the symbol as further actions on the symbol would result
+   in bad data.  All access to obj->symbol should be gated by
+   SYMPY_REQUIRE_VALID which will raise an exception on invalid
+   symbols.  */
+static void
+del_objfile_symbols (struct objfile *objfile, void *datum)
+{
+  symbol_object *obj = datum;
+  while (obj)
+    {
+      symbol_object *next = obj->next;
+
+      obj->symbol = NULL;
+      obj->next = NULL;
+      obj->prev = NULL;
+
+      obj = next;
+    }
+}
+
+void
+gdbpy_initialize_symbols (void)
+{
+  if (PyType_Ready (&symbol_object_type) < 0)
+    return;
+
+  /* Register an objfile "free" callback so we can properly
+     invalidate symbol when an object file that is about to be
+     deleted.  */
+  sympy_objfile_data_key
+    = register_objfile_data_with_cleanup (NULL, del_objfile_symbols);
+
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_UNDEF", LOC_UNDEF);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_CONST", LOC_CONST);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_STATIC", LOC_STATIC);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REGISTER", LOC_REGISTER);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_ARG", LOC_ARG);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REF_ARG", LOC_REF_ARG);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_LOCAL", LOC_LOCAL);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_TYPEDEF", LOC_TYPEDEF);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_LABEL", LOC_LABEL);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_BLOCK", LOC_BLOCK);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_CONST_BYTES",
+			   LOC_CONST_BYTES);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_UNRESOLVED", LOC_UNRESOLVED);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_OPTIMIZED_OUT",
+			   LOC_OPTIMIZED_OUT);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_COMPUTED", LOC_COMPUTED);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_LOC_REGPARM_ADDR",
+			   LOC_REGPARM_ADDR);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_UNDEF_DOMAIN", UNDEF_DOMAIN);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_VAR_DOMAIN", VAR_DOMAIN);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_STRUCT_DOMAIN", STRUCT_DOMAIN);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_LABEL_DOMAIN", LABEL_DOMAIN);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_VARIABLES_DOMAIN",
+			   VARIABLES_DOMAIN);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_FUNCTIONS_DOMAIN",
+			   FUNCTIONS_DOMAIN);
+  PyModule_AddIntConstant (gdb_module, "SYMBOL_TYPES_DOMAIN", TYPES_DOMAIN);
+
+  Py_INCREF (&symbol_object_type);
+  PyModule_AddObject (gdb_module, "Symbol", (PyObject *) &symbol_object_type);
+}
+
+
+
+static PyGetSetDef symbol_object_getset[] = {
+  { "symtab", sympy_get_symtab, NULL,
+    "Symbol table in which the symbol appears.", NULL },
+  { "name", sympy_get_name, NULL,
+    "Name of the symbol, as it appears in the source code.", NULL },
+  { "linkage_name", sympy_get_linkage_name, NULL,
+    "Name of the symbol, as used by the linker (i.e., may be mangled).", NULL },
+  { "print_name", sympy_get_print_name, NULL,
+    "Name of the symbol in a form suitable for output.\n\
+This is either name or linkage_name, depending on whether the user asked GDB\n\
+to display demangled or mangled names.", NULL },
+  { "addr_class", sympy_get_addr_class, NULL, "Address class of the symbol." },
+  { "is_argument", sympy_is_argument, NULL,
+    "True if the symbol is an argument of a function." },
+  { "is_constant", sympy_is_constant, NULL,
+    "True if the symbol is a constant." },
+  { "is_function", sympy_is_function, NULL,
+    "True if the symbol is a function or method." },
+  { "is_variable", sympy_is_variable, NULL,
+    "True if the symbol is a variable." },
+  { NULL }  /* Sentinel */
+};
+
+PyTypeObject symbol_object_type = {
+  PyObject_HEAD_INIT (NULL)
+  0,				  /*ob_size*/
+  "gdb.Symbol",			  /*tp_name*/
+  sizeof (symbol_object),	  /*tp_basicsize*/
+  0,				  /*tp_itemsize*/
+  sympy_dealloc,		  /*tp_dealloc*/
+  0,				  /*tp_print*/
+  0,				  /*tp_getattr*/
+  0,				  /*tp_setattr*/
+  0,				  /*tp_compare*/
+  0,				  /*tp_repr*/
+  0,				  /*tp_as_number*/
+  0,				  /*tp_as_sequence*/
+  0,				  /*tp_as_mapping*/
+  0,				  /*tp_hash */
+  0,				  /*tp_call*/
+  sympy_str,			  /*tp_str*/
+  0,				  /*tp_getattro*/
+  0,				  /*tp_setattro*/
+  0,				  /*tp_as_buffer*/
+  Py_TPFLAGS_DEFAULT,		  /*tp_flags*/
+  "GDB symbol object",		  /*tp_doc */
+  0,				  /*tp_traverse */
+  0,				  /*tp_clear */
+  0,				  /*tp_richcompare */
+  0,				  /*tp_weaklistoffset */
+  0,				  /*tp_iter */
+  0,				  /*tp_iternext */
+  0,				  /*tp_methods */
+  0,				  /*tp_members */
+  symbol_object_getset		  /*tp_getset */
+};
diff --git a/gdb/python/py-symtab.c b/gdb/python/py-symtab.c
new file mode 100644
index 0000000..c1592b5
--- /dev/null
+++ b/gdb/python/py-symtab.c
@@ -0,0 +1,550 @@
+/* Python interface to symbol tables.
+
+   Copyright (C) 2008, 2009, 2010 Free Software Foundation, Inc.
+
+   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 3 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, see <http://www.gnu.org/licenses/>.  */
+
+#include "defs.h"
+#include "charset.h"
+#include "symtab.h"
+#include "source.h"
+#include "python-internal.h"
+#include "exceptions.h"
+#include "objfiles.h"
+
+typedef struct stpy_symtab_object {
+  PyObject_HEAD
+  /* The GDB Symbol table structure.  */
+  struct symtab *symtab;
+  /* A symtab object is associated with an objfile, so keep track with
+     a doubly-linked list, rooted in the objfile.  This allows
+     invalidation of the underlying struct symtab when the objfile is
+     deleted.  */
+  struct stpy_symtab_object *prev;
+  struct stpy_symtab_object *next;
+} symtab_object;
+
+static PyTypeObject symtab_object_type;
+static const struct objfile_data *stpy_objfile_data_key;
+
+/* Require a valid symbol table.  All access to symtab_object->symtab
+   should be gated by this call.  This must be called inside a
+   TRY_CATCH, or another context in which a gdb exception is
+   allowed.  */
+#define STPY_REQUIRE_VALID(symtab_obj, symtab)		\
+  do {							\
+      symtab = symtab_object_to_symtab (symtab_obj);	\
+      if (symtab == NULL)			        \
+	error (_("Symbol table is invalid."));		\
+    } while (0)
+
+typedef struct salpy_sal_object {
+  PyObject_HEAD
+  /* The GDB Symbol table structure.  */
+  symtab_object *symtab;
+  /* The GDB Symbol table and line structure.  */
+  struct symtab_and_line *sal;
+  /* A Symtab and line object is associated with an objfile, so keep
+     track with a doubly-linked list, rooted in the objfile.  This
+     allows invalidation of the underlying struct symtab_and_line
+     when the objfile is deleted.  */
+  struct salpy_sal_object *prev;
+  struct salpy_sal_object *next;
+} sal_object;
+
+static PyTypeObject sal_object_type;
+static const struct objfile_data *salpy_objfile_data_key;
+
+/* Require a valid symbol table and line object.  All access to
+   sal_object->sal should be gated by this call.  This must be called
+   inside a  TRY_CATCH, or another context in which a gdb exception is
+   allowed.  */
+#define SALPY_REQUIRE_VALID(sal_obj, sal)		\
+  do {							\
+      sal = sal_object_to_symtab_and_line (sal_obj);	\
+      if (sal == NULL)					\
+	error (_("Symbol Table and Line is invalid."));	\
+    } while (0)
+
+static PyObject *
+stpy_str (PyObject *self)
+{
+  char *s;
+  PyObject *result;
+  struct symtab *symtab = NULL;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      STPY_REQUIRE_VALID (self, symtab);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  s = xstrprintf ("symbol table for %s",
+		  symtab->filename);
+
+  result = PyString_FromString (s);
+  xfree (s);
+
+  return result;
+}
+
+static PyObject *
+stpy_get_filename (PyObject *self, void *closure)
+{
+  PyObject *str_obj;
+  struct symtab *symtab = NULL;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      STPY_REQUIRE_VALID (self, symtab);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  str_obj = PyString_Decode (symtab->filename,
+			     strlen (symtab->filename),
+			     host_charset (), NULL);
+  return str_obj;
+}
+
+static PyObject *
+stpy_get_objfile (PyObject *self, void *closure)
+{
+  struct symtab *symtab = NULL;
+  volatile struct gdb_exception except;
+  PyObject *result;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      STPY_REQUIRE_VALID (self, symtab);
+    }
+
+  result = objfile_to_objfile_object (symtab->objfile);
+  Py_INCREF (result);
+  return result;
+}
+
+static PyObject *
+stpy_fullname (PyObject *self, PyObject *args)
+{
+  char *fullname;
+  struct symtab *symtab = NULL;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      STPY_REQUIRE_VALID (self, symtab);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  fullname = symtab_to_fullname (symtab);
+  if (fullname)
+    return PyString_Decode (fullname, strlen (fullname), host_charset (), NULL);
+
+  Py_RETURN_NONE;
+}
+
+static PyObject *
+salpy_str (PyObject *self)
+{
+  char *s, *filename;
+  sal_object *sal_obj;
+  PyObject *result;
+  struct symtab_and_line *sal = NULL;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      SALPY_REQUIRE_VALID (self, sal);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  sal_obj = (sal_object *) self;
+  filename = (sal_obj->symtab == (symtab_object *) Py_None)
+    ? "<unknown>" : sal_obj->symtab->symtab->filename;
+
+  s = xstrprintf ("symbol and line for %s, line %d", filename,
+		  sal->line);
+
+  result = PyString_FromString (s);
+  xfree (s);
+
+  return result;
+}
+
+static void
+stpy_dealloc (PyObject *obj)
+{
+  symtab_object *symtab = (symtab_object *) obj;
+
+  if (symtab->prev)
+    symtab->prev->next = symtab->next;
+  else if (symtab->symtab)
+    {
+      set_objfile_data (symtab->symtab->objfile,
+			stpy_objfile_data_key, symtab->next);
+    }
+  if (symtab->next)
+    symtab->next->prev = symtab->prev;
+  symtab->symtab = NULL;
+}
+
+
+static PyObject *
+salpy_get_pc (PyObject *self, void *closure)
+{
+  struct symtab_and_line *sal = NULL;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      SALPY_REQUIRE_VALID (self, sal);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  return PyLong_FromUnsignedLongLong (sal->pc);
+}
+
+static PyObject *
+salpy_get_line (PyObject *self, void *closure)
+{
+  struct symtab_and_line *sal = NULL;
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      SALPY_REQUIRE_VALID (self, sal);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  return PyLong_FromUnsignedLongLong (sal->line);
+}
+
+static PyObject *
+salpy_get_symtab (PyObject *self, void *closure)
+{
+  struct symtab_and_line *sal;
+  volatile struct gdb_exception except;
+  sal_object *self_sal = (sal_object *) self;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      SALPY_REQUIRE_VALID (self, sal);
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
+  Py_INCREF (self_sal->symtab);
+
+  return (PyObject *) self_sal->symtab;
+}
+
+static void
+salpy_dealloc (PyObject *self)
+{
+  sal_object *self_sal = (sal_object *) self;
+
+  if (self_sal->prev)
+    self_sal->prev->next = self_sal->next;
+  else if (self_sal->symtab != (symtab_object * ) Py_None)
+    set_objfile_data (self_sal->symtab->symtab->objfile,
+			salpy_objfile_data_key, self_sal->next);
+
+  if (self_sal->next)
+    self_sal->next->prev = self_sal->prev;
+
+  Py_DECREF (self_sal->symtab);
+  xfree (self_sal->sal);
+  self_sal->ob_type->tp_free (self);
+}
+
+/* Given a sal, and a sal_object that has previously been
+   allocated and initialized, populate the sal_object with the
+   struct sal data.  Also, register the sal_object life-cycle
+   with the life-cycle of the the object file associated with this
+   sal, if needed.  */
+static void
+set_sal (sal_object *sal_obj, struct symtab_and_line sal)
+{
+
+  symtab_object *symtab_obj;
+
+  if (sal.symtab)
+    {
+      symtab_obj = (symtab_object *) symtab_to_symtab_object (sal.symtab);
+      if (symtab_obj == NULL)
+	{
+	  Py_DECREF (sal_obj);
+	  return;
+	}
+    }
+  else
+    {
+      symtab_obj = (symtab_object *) Py_None;
+      Py_INCREF (Py_None);
+    }
+
+  sal_obj->sal = xmemdup (&sal, sizeof (struct symtab_and_line),
+			  sizeof(struct symtab_and_line));
+  sal_obj->symtab = symtab_obj;
+  sal_obj->prev = NULL;
+
+  /* If the SAL does not have a symtab, we do not add it to the
+     objfile cleanup observer linked list.  */
+  if (sal_obj->symtab != (symtab_object *)Py_None)
+    {
+      sal_obj->next = objfile_data (sal_obj->symtab->symtab->objfile, salpy_objfile_data_key);
+      if (sal_obj->next)
+	sal_obj->next->prev = sal_obj;
+      set_objfile_data (sal_obj->symtab->symtab->objfile, salpy_objfile_data_key, sal_obj);
+    }
+  else
+    sal_obj->next = NULL;
+}
+
+/* Given a symtab, and a symtab_object that has previously been
+   allocated and initialized, populate the symtab_object with the
+   struct symtab data.  Also, register the symtab_object life-cycle
+   with the life-cycle of the the object file associated with this
+   symtab, if needed.  */
+static void
+set_symtab (symtab_object *obj, struct symtab *symtab)
+{
+  obj->symtab = symtab;
+  obj->prev = NULL;
+  if (symtab)
+    {
+      obj->next = objfile_data (symtab->objfile, stpy_objfile_data_key);
+      if (obj->next)
+	obj->next->prev = obj;
+      set_objfile_data (symtab->objfile, stpy_objfile_data_key, obj);
+    }
+  else
+    obj->next = NULL;
+}
+
+/* Create a new symbol table (gdb.Symtab) object that encapsulates the
+   symtab structure from GDB.  */
+PyObject *
+symtab_to_symtab_object (struct symtab *symtab)
+{
+  symtab_object *symtab_obj;
+
+  symtab_obj = PyObject_New (symtab_object, &symtab_object_type);
+  if (symtab_obj)
+    set_symtab (symtab_obj, symtab);
+
+  return (PyObject *) symtab_obj;
+}
+
+/* Create a new symtab and line (gdb.Symtab_and_line) object
+   that encapsulates the symtab_and_line structure from GDB.  */
+PyObject *
+symtab_and_line_to_sal_object (struct symtab_and_line sal)
+
+{
+  sal_object *sal_obj;
+  symtab_object *symtab_obj;
+
+  sal_obj = PyObject_New (sal_object, &sal_object_type);
+
+  if (sal_obj)
+    set_sal (sal_obj, sal);
+
+  return (PyObject *) sal_obj;
+}
+
+/* Return struct symtab_and_line reference that is wrapped by this
+   object.  */
+struct symtab_and_line *
+sal_object_to_symtab_and_line (PyObject *obj)
+{
+  if (! PyObject_TypeCheck (obj, &sal_object_type))
+    return NULL;
+  return ((sal_object *) obj)->sal;
+}
+
+/* Return struct symtab reference that is wrapped by this object.  */
+struct symtab *
+symtab_object_to_symtab (PyObject *obj)
+{
+  if (! PyObject_TypeCheck (obj, &symtab_object_type))
+    return NULL;
+  return ((symtab_object *) obj)->symtab;
+}
+
+/* This function is called when an objfile is about to be freed.
+   Invalidate the symbol table as further actions on the symbol table
+   would result in bad data.  All access to obj->symtab should be
+   gated by STPY_REQUIRE_VALID which will raise an exception on
+   invalid symbol tables.  */
+static void
+del_objfile_symtab (struct objfile *objfile, void *datum)
+{
+  symtab_object *obj = datum;
+  while (obj)
+    {
+      symtab_object *next = obj->next;
+
+      obj->symtab = NULL;
+      obj->next = NULL;
+      obj->prev = NULL;
+      obj = next;
+    }
+}
+
+/* This function is called when an objfile is about to be freed.
+   Invalidate the sal object as further actions on the sal
+   would result in bad data.  All access to obj->sal should be
+   gated by SALPY_REQUIRE_VALID which will raise an exception on
+   invalid symbol table and line objects.  */
+static void
+del_objfile_sal (struct objfile *objfile, void *datum)
+{
+  sal_object *obj = datum;
+  while (obj)
+    {
+      sal_object *next = obj->next;
+
+      obj->symtab = NULL;
+      obj->next = NULL;
+      obj->prev = NULL;
+      xfree (obj->sal);
+      obj->sal = NULL;
+
+      obj = next;
+    }
+}
+
+void
+gdbpy_initialize_symtabs (void)
+{
+  symtab_object_type.tp_new = PyType_GenericNew;
+  if (PyType_Ready (&symtab_object_type) < 0)
+    return;
+
+  sal_object_type.tp_new = PyType_GenericNew;
+  if (PyType_Ready (&sal_object_type) < 0)
+    return;
+
+  /* Register an objfile "free" callback so we can properly
+     invalidate symbol tables, and symbol table and line data
+     structures when an object file that is about to be
+     deleted.  */
+  stpy_objfile_data_key
+    = register_objfile_data_with_cleanup (NULL, del_objfile_symtab);
+  salpy_objfile_data_key
+    = register_objfile_data_with_cleanup (NULL, del_objfile_sal);
+
+  Py_INCREF (&symtab_object_type);
+  PyModule_AddObject (gdb_module, "Symtab", (PyObject *) &symtab_object_type);
+
+  Py_INCREF (&sal_object_type);
+  PyModule_AddObject (gdb_module, "Symtab_and_line",
+		      (PyObject *) &sal_object_type);
+}
+
+
+
+static PyGetSetDef symtab_object_getset[] = {
+  { "filename", stpy_get_filename, NULL,
+    "The symbol table's source filename.", NULL },
+  { "objfile", stpy_get_objfile, NULL, "The symtab's objfile.",
+    NULL },
+  {NULL}  /* Sentinel */
+};
+
+static PyMethodDef symtab_object_methods[] = {
+  { "fullname", stpy_fullname, METH_NOARGS,
+    "Return the symtab's full source filename." },
+  {NULL}  /* Sentinel */
+};
+
+static PyTypeObject symtab_object_type = {
+  PyObject_HEAD_INIT (NULL)
+  0,				  /*ob_size*/
+  "gdb.Symtab",			  /*tp_name*/
+  sizeof (symtab_object),	  /*tp_basicsize*/
+  0,				  /*tp_itemsize*/
+  stpy_dealloc,			  /*tp_dealloc*/
+  0,				  /*tp_print*/
+  0,				  /*tp_getattr*/
+  0,				  /*tp_setattr*/
+  0,				  /*tp_compare*/
+  0,				  /*tp_repr*/
+  0,				  /*tp_as_number*/
+  0,				  /*tp_as_sequence*/
+  0,				  /*tp_as_mapping*/
+  0,				  /*tp_hash */
+  0,				  /*tp_call*/
+  stpy_str,			  /*tp_str*/
+  0,				  /*tp_getattro*/
+  0,				  /*tp_setattro*/
+  0,				  /*tp_as_buffer*/
+  Py_TPFLAGS_DEFAULT,		  /*tp_flags*/
+  "GDB symtab object",		  /*tp_doc */
+  0,				  /*tp_traverse */
+  0,				  /*tp_clear */
+  0,				  /*tp_richcompare */
+  0,				  /*tp_weaklistoffset */
+  0,				  /*tp_iter */
+  0,				  /*tp_iternext */
+  symtab_object_methods,	  /*tp_methods */
+  0,				  /*tp_members */
+  symtab_object_getset		  /*tp_getset */
+};
+
+static PyGetSetDef sal_object_getset[] = {
+  { "symtab", salpy_get_symtab, NULL, "Symtab object.", NULL },
+  { "pc", salpy_get_pc, NULL, "Return the symtab_and_line's pc.", NULL },
+  { "line", salpy_get_line, NULL,
+    "Return the symtab_and_line's line.", NULL },
+  {NULL}  /* Sentinel */
+};
+
+static PyTypeObject sal_object_type = {
+  PyObject_HEAD_INIT (NULL)
+  0,				  /*ob_size*/
+  "gdb.Symtab_and_line",	  /*tp_name*/
+  sizeof (sal_object),		  /*tp_basicsize*/
+  0,				  /*tp_itemsize*/
+  salpy_dealloc,		  /*tp_dealloc*/
+  0,				  /*tp_print*/
+  0,				  /*tp_getattr*/
+  0,				  /*tp_setattr*/
+  0,				  /*tp_compare*/
+  0,				  /*tp_repr*/
+  0,				  /*tp_as_number*/
+  0,				  /*tp_as_sequence*/
+  0,				  /*tp_as_mapping*/
+  0,				  /*tp_hash */
+  0,				  /*tp_call*/
+  salpy_str,			  /*tp_str*/
+  0,				  /*tp_getattro*/
+  0,				  /*tp_setattro*/
+  0,				  /*tp_as_buffer*/
+  Py_TPFLAGS_DEFAULT,		  /*tp_flags*/
+  "GDB symtab_and_line object",	  /*tp_doc */
+  0,				  /*tp_traverse */
+  0,				  /*tp_clear */
+  0,				  /*tp_richcompare */
+  0,				  /*tp_weaklistoffset */
+  0,				  /*tp_iter */
+  0,				  /*tp_iternext */
+  0,				  /*tp_methods */
+  0,				  /*tp_members */
+  sal_object_getset		  /*tp_getset */
+};
diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
index 9196f08..eaf84fc 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -61,32 +61,51 @@ typedef int Py_ssize_t;
 #define PyEval_ReleaseLock() 0
 #endif
 
+struct block;
+struct symbol;
+struct symtab_and_line;
 struct value;
 struct language_defn;
 
 extern PyObject *gdb_module;
 extern PyTypeObject value_object_type;
+extern PyTypeObject block_object_type;
+extern PyTypeObject symbol_object_type;
 
 PyObject *gdbpy_history (PyObject *self, PyObject *args);
 PyObject *gdbpy_frame_stop_reason_string (PyObject *, PyObject *);
+PyObject *gdbpy_lookup_symbol (PyObject *self, PyObject *args, PyObject *kw);
 PyObject *gdbpy_selected_frame (PyObject *self, PyObject *args);
+PyObject *gdbpy_block_for_pc (PyObject *self, PyObject *args);
 PyObject *gdbpy_lookup_type (PyObject *self, PyObject *args, PyObject *kw);
 PyObject *gdbpy_create_lazy_string_object (CORE_ADDR address, long length,
 					   const char *encoding, struct type *type);
 
+PyObject *symtab_and_line_to_sal_object (struct symtab_and_line sal);
+PyObject *symtab_to_symtab_object (struct symtab *symtab);
+PyObject *symbol_to_symbol_object (struct symbol *sym);
+PyObject *block_to_block_object (struct block *block, struct objfile *objfile);
 PyObject *value_to_value_object (struct value *v);
 PyObject *type_to_type_object (struct type *);
 PyObject *objfile_to_objfile_object (struct objfile *);
 
 PyObject *objfpy_get_printers (PyObject *, void *);
 
+struct block *block_object_to_block (PyObject *obj);
+struct symbol *symbol_object_to_symbol (PyObject *obj);
 struct value *value_object_to_value (PyObject *self);
 struct value *convert_value_from_python (PyObject *obj);
 struct type *type_object_to_type (PyObject *obj);
+struct symtab *symtab_object_to_symtab (PyObject *obj);
+struct symtab_and_line *sal_object_to_symtab_and_line (PyObject *obj);
 
 void gdbpy_initialize_values (void);
 void gdbpy_initialize_frames (void);
+void gdbpy_initialize_symtabs (void);
 void gdbpy_initialize_commands (void);
+void gdbpy_initialize_symbols (void);
+void gdbpy_initialize_symtabs (void);
+void gdbpy_initialize_blocks (void);
 void gdbpy_initialize_types (void);
 void gdbpy_initialize_functions (void);
 void gdbpy_initialize_objfile (void);
diff --git a/gdb/python/python.c b/gdb/python/python.c
index 29386c9..3d38de6 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -644,6 +644,9 @@ Enables or disables auto-loading of Python code when an object is opened."),
   gdbpy_initialize_values ();
   gdbpy_initialize_frames ();
   gdbpy_initialize_commands ();
+  gdbpy_initialize_symbols ();
+  gdbpy_initialize_symtabs ();
+  gdbpy_initialize_blocks ();
   gdbpy_initialize_functions ();
   gdbpy_initialize_types ();
   gdbpy_initialize_objfile ();
@@ -724,7 +727,14 @@ Return a string explaining unwind stop reason." },
     METH_VARARGS | METH_KEYWORDS,
     "lookup_type (name [, block]) -> type\n\
 Return a Type corresponding to the given name." },
-
+  { "lookup_symbol", (PyCFunction) gdbpy_lookup_symbol,
+    METH_VARARGS | METH_KEYWORDS,
+    "lookup_symbol (name [, block] [, domain]) -> (symbol, is_field_of_this)\n\
+Return a tuple with the symbol corresponding to the given name (or None) and\n\
+a boolean indicating if name is a field of the current implied argument\n\
+`this' (when the current language is object-oriented)." },
+  { "block_for_pc", gdbpy_block_for_pc, METH_VARARGS,
+    "Return the block containing the given pc value, or None." },
   { "parse_and_eval", gdbpy_parse_and_eval, METH_VARARGS,
     "parse_and_eval (String) -> Value.\n\
 Parse String as an expression, evaluate it, and return the result as a Value."
diff --git a/gdb/testsuite/gdb.python/Makefile.in b/gdb/testsuite/gdb.python/Makefile.in
index 3e81bd3..06f8c9c 100644
--- a/gdb/testsuite/gdb.python/Makefile.in
+++ b/gdb/testsuite/gdb.python/Makefile.in
@@ -1,7 +1,8 @@
 VPATH = @srcdir@
 srcdir = @srcdir@
 
-EXECUTABLES = py-type py-value py-prettyprint py-template
+EXECUTABLES = py-type py-value py-prettyprint py-template py-block \
+	py-symbol
 
 all info install-info dvi install uninstall installcheck check:
 	@echo "Nothing to be done for $@..."
diff --git a/gdb/testsuite/gdb.python/py-block.c b/gdb/testsuite/gdb.python/py-block.c
new file mode 100644
index 0000000..a748044
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-block.c
@@ -0,0 +1,41 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2010 Free Software Foundation, Inc.
+
+   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 3 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, see  <http://www.gnu.org/licenses/>.
+*/
+
+
+
+int block_func (void)
+{
+  int i = 0;
+  {
+    double i = 1.0;
+    double f = 2.0;
+    {
+      const char *i = "stuff";
+      const char *f = "foo";
+      const char *b = "bar";
+      return 0; /* Block break here.  */
+    }
+  }
+}
+
+
+int main (int argc, char *argv[])
+{
+  block_func ();
+  return 0; /* Break at end. */
+}
diff --git a/gdb/testsuite/gdb.python/py-block.exp b/gdb/testsuite/gdb.python/py-block.exp
new file mode 100644
index 0000000..31345e3
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-block.exp
@@ -0,0 +1,84 @@
+# Copyright (C) 2010 Free Software Foundation, Inc.
+#
+# 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 3 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, see <http://www.gnu.org/licenses/>.
+
+# This file is part of the GDB testsuite.  It tests the mechanism
+# exposing values to Python.
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+set testfile "py-block"
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
+    untested "Couldn't compile ${srcfile}"
+    return -1
+}
+
+# Run a command in GDB, and report a failure if a Python exception is thrown.
+# If report_pass is true, report a pass if no exception is thrown.
+proc gdb_py_test_silent_cmd {cmd name report_pass} {
+    global gdb_prompt
+
+  gdb_test_multiple $cmd $name {
+      -re "Traceback.*$gdb_prompt $"  { fail $name }
+      -re "$gdb_prompt $"	      { if $report_pass { pass $name } }
+  }
+}
+
+# Start with a fresh gdb.
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+gdb_test_multiple "python print 'hello, world!'" "verify python support" {
+    -re "not supported.*$gdb_prompt $"	{
+      unsupported "python support is disabled"
+      return -1
+    }
+    -re "$gdb_prompt $"	{}
+}
+
+if ![runto_main] then {
+    fail "Can't run to main"
+    return 0
+}
+
+global hex decimal
+gdb_breakpoint [gdb_get_line_number "Block break here."]
+gdb_continue_to_breakpoint "Block break here."
+
+# Test initial innermost block.
+gdb_py_test_silent_cmd "python frame = gdb.selected_frame()" "Get Frame" 0
+gdb_py_test_silent_cmd "python block = frame.block()" "Get block" 0
+gdb_test "python print block" "<gdb.Block object at $hex>" "Check block not None"
+gdb_test "python print block.function" "None" "First anonymous block"
+gdb_test "python print block.start" "${decimal}" "Check start not None"
+gdb_test "python print block.end" "${decimal}" "Check end not None"
+
+# Move up superblock(s) until we reach function block_func.
+gdb_test "python block = block.superblock" "" "Get superblock"
+gdb_test "python print block.function" "None" "Second anonymous block"
+gdb_test "python block = block.superblock" "" "Get superblock"
+gdb_test "python print block.function" "symbol for block_func"
+
+# Switch frames, then test for main block.
+gdb_test "up" ""
+gdb_py_test_silent_cmd "python frame = gdb.selected_frame()" "Get Frame" 0
+gdb_py_test_silent_cmd "python block = frame.block()" "Get block" 0
+gdb_test "python print block" "<gdb.Block object at $hex>" "Check block not None"
+gdb_test "python print block.function" "symbol for main" "main block"
diff --git a/gdb/testsuite/gdb.python/py-symbol.c b/gdb/testsuite/gdb.python/py-symbol.c
new file mode 100644
index 0000000..0c8bb60
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-symbol.c
@@ -0,0 +1,62 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2010 Free Software Foundation, Inc.
+
+   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 3 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, see  <http://www.gnu.org/licenses/>.
+*/
+
+#ifdef __cplusplus
+class SimpleClass
+{
+ private:
+  int i;
+
+ public:
+  void seti (int arg)
+  {
+    i = arg;
+  }
+
+  int valueofi (void)
+  {
+    return i; /* Break in class. */
+  }
+};
+#endif
+
+int func (int arg)
+{
+  int i = 2;
+  i = i * arg;
+  return arg; /* Block break here.  */
+}
+
+int main (int argc, char *argv[])
+{
+#ifdef __cplusplus
+  SimpleClass sclass;
+#endif
+  int a = 0;
+  int result;
+  enum tag {one, two, three};
+  enum tag t = one;
+
+  result = func (42);
+
+#ifdef __cplusplus
+  sclass.seti (42);
+  sclass.valueofi ();
+#endif
+  return 0; /* Break at end.  */
+}
diff --git a/gdb/testsuite/gdb.python/py-symbol.exp b/gdb/testsuite/gdb.python/py-symbol.exp
new file mode 100644
index 0000000..23b7844
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-symbol.exp
@@ -0,0 +1,137 @@
+# Copyright (C) 2010 Free Software Foundation, Inc.
+
+# 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 3 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, see <http://www.gnu.org/licenses/>.
+
+# This file is part of the GDB testsuite.  It tests the mechanism
+# exposing values to Python.
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+set testfile "py-symbol"
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
+    untested "Couldn't compile ${srcfile}"
+    return -1
+}
+
+# Run a command in GDB, and report a failure if a Python exception is thrown.
+# If report_pass is true, report a pass if no exception is thrown.
+proc gdb_py_test_silent_cmd {cmd name report_pass} {
+  global gdb_prompt
+
+  gdb_test_multiple $cmd $name {
+      -re "Traceback.*$gdb_prompt $"  { fail $name }
+      -re "$gdb_prompt $"	      { if $report_pass { pass $name } }
+  }
+}
+
+# Start with a fresh gdb.
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+gdb_test_multiple "python print 'hello, world!'" "verify python support" {
+    -re "not supported.*$gdb_prompt $"	{
+      unsupported "python support is disabled"
+      return -1
+    }
+    -re "$gdb_prompt $"	{}
+}
+
+if ![runto_main] then {
+    fail "Can't run to main"
+    return 0
+}
+
+global hex decimal
+
+gdb_breakpoint [gdb_get_line_number "Block break here."]
+gdb_continue_to_breakpoint "Block break here."
+gdb_py_test_silent_cmd "python frame = gdb.selected_frame()" "Get Frame" 0
+gdb_py_test_silent_cmd "python block = frame.block()" "Get block" 0
+
+# Test is_argument attribute.
+gdb_py_test_silent_cmd "python arg = gdb.lookup_symbol(\"arg\")" "Get variable a" 0
+gdb_test "python print arg\[0\].is_variable" "False" "Test arg.is_variable"
+gdb_test "python print arg\[0\].is_constant" "False" "Test arg.is_constant"
+gdb_test "python print arg\[0\].is_argument" "True" "Test arg.is_argument"
+gdb_test "python print arg\[0\].is_function" "False" "Test arg.is_function"
+
+# Test is_function attribute.
+gdb_py_test_silent_cmd "python func = frame.block().function" "Get block" 0
+gdb_test "python print func.is_variable" "False" "Test func.is_variable"
+gdb_test "python print func.is_constant" "False" "Test func.is_constant"
+gdb_test "python print func.is_argument" "False" "Test func.is_argument"
+gdb_test "python print func.is_function" "True" "Test func.is_function"
+gdb_test "python print func.name" "func" "Test func.name"
+gdb_test "python print func.print_name" "func" "Test func.print_name"
+gdb_test "python print func.linkage_name" "func" "Test func.linkage_name"
+gdb_test "python print func.addr_class == gdb.SYMBOL_LOC_BLOCK" "True" "Test func.addr_class"
+
+gdb_breakpoint [gdb_get_line_number "Break at end."]
+gdb_continue_to_breakpoint "Break at end."
+gdb_py_test_silent_cmd "python frame = gdb.selected_frame()" "Get Frame" 0
+
+# Test is_variable attribute.
+gdb_py_test_silent_cmd "python a = gdb.lookup_symbol(\'a\')" "Get variable a" 0
+gdb_test "python print a\[0\].is_variable" "True" "Test a.is_variable"
+gdb_test "python print a\[0\].is_constant" "False" "Test a.is_constant"
+gdb_test "python print a\[0\].is_argument" "False" "Test a.is_argument"
+gdb_test "python print a\[0\].is_function" "False" "Test a.is_function"
+gdb_test "python print a\[0\].addr_class == gdb.SYMBOL_LOC_COMPUTED" "True" "Test a.addr_class"
+
+# Test is_constant attribute
+gdb_py_test_silent_cmd "python t = gdb.lookup_symbol(\"one\")" "Get variable a" 0
+gdb_test "python print t\[0\].is_variable" "False" "Test t.is_variable"
+gdb_test "python print t\[0\].is_constant" "True" "Test t.is_constant"
+gdb_test "python print t\[0\].is_argument" "False" "Test t.is_argument"
+gdb_test "python print t\[0\].is_function" "False" "Test t.is_function"
+gdb_test "python print t\[0\].addr_class == gdb.SYMBOL_LOC_CONST" "True" "Test t.addr_class"
+gdb_test "python print t\[0\].symtab" "symbol table for.*" "Get symtab"
+
+# C++ tests
+# Recompile binary.
+ if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable "debug c++"] != "" } {
+     untested "Couldn't compile ${srcfile} in c++ mode"
+     return -1
+ }
+
+# Start with a fresh gdb.
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+if ![runto_main] then {
+    fail "Can't run to main"
+    return 0
+}
+
+gdb_breakpoint [gdb_get_line_number "Break in class."]
+gdb_continue_to_breakpoint "Break in class."
+
+gdb_py_test_silent_cmd "python cplusframe = gdb.selected_frame()" "Get Frame" 0
+gdb_py_test_silent_cmd "python cplusfunc = cplusframe.block().function" "Get block" 0
+gdb_test "python print cplusfunc.is_variable" "False" "Test func.is_variable"
+gdb_test "python print cplusfunc.is_constant" "False" "Test func.is_constant"
+gdb_test "python print cplusfunc.is_argument" "False" "Test func.is_argument"
+gdb_test "python print cplusfunc.is_function" "True" "Test func.is_function"
+gdb_test "python print cplusfunc.name" "SimpleClass::valueofi().*" "Test func.name"
+gdb_test "python print cplusfunc.print_name" "SimpleClass::valueofi().*" "Test func.print_name"
+gdb_test "python print cplusfunc.linkage_name" "_ZN11SimpleClass8valueofiEv" "Test func.linkage_name"
+gdb_test "python print cplusfunc.addr_class == gdb.SYMBOL_LOC_BLOCK" "True" "Test func.addr_class"
diff --git a/gdb/testsuite/gdb.python/py-symtab.exp b/gdb/testsuite/gdb.python/py-symtab.exp
new file mode 100644
index 0000000..a43207b
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-symtab.exp
@@ -0,0 +1,78 @@
+# Copyright (C) 2010 Free Software Foundation, Inc.
+
+# 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 3 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, see <http://www.gnu.org/licenses/>.
+
+# This file is part of the GDB testsuite.  It tests the mechanism
+# exposing values to Python.
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+set testfile "py-symbol"
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
+    untested "Couldn't compile ${srcfile}"
+    return -1
+}
+
+# Run a command in GDB, and report a failure if a Python exception is thrown.
+# If report_pass is true, report a pass if no exception is thrown.
+proc gdb_py_test_silent_cmd {cmd name report_pass} {
+  global gdb_prompt
+
+  gdb_test_multiple $cmd $name {
+      -re "Traceback.*$gdb_prompt $"  { fail $name }
+      -re "$gdb_prompt $"	      { if $report_pass { pass $name } }
+  }
+}
+
+# Start with a fresh gdb.
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+gdb_test_multiple "python print 'hello, world!'" "verify python support" {
+    -re "not supported.*$gdb_prompt $"	{
+      unsupported "python support is disabled"
+      return -1
+    }
+    -re "$gdb_prompt $"	{}
+}
+
+if ![runto_main] then {
+    fail "Can't run to main"
+    return 0
+}
+
+global hex decimal
+
+# Setup and get the symbol table.
+gdb_breakpoint [gdb_get_line_number "Block break here."]
+gdb_continue_to_breakpoint "Block break here."
+gdb_py_test_silent_cmd "python frame = gdb.selected_frame()" "Get Frame" 0
+gdb_py_test_silent_cmd "python sal = frame.find_sal()" "Get block" 0
+gdb_py_test_silent_cmd "python symtab = sal.symtab" "Get block" 0
+
+# Test sal.
+gdb_test "python print sal.symtab" "gdb/testsuite/gdb.python/py-symbol.c.*" "Test symtab"
+gdb_test "python print sal.pc" "${decimal}" "Test sal.pc"
+gdb_test "python print sal.line" "42" "Test sal.line"
+
+# Test symbol table.
+gdb_test "python print symtab.filename" "testsuite/gdb.python/py-symbol.c.*" "Test symtab.filename"
+gdb_test "python print symtab.objfile" "<gdb.Objfile object at ${hex}>" "Test symtab.objfile"
+gdb_test "python print symtab.fullname()" "testsuite/gdb.python/py-symbol.c.*" "Test symtab.fullname"


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