New python script adding pretty printers for types defined in GDB.

        * gdb-gdb.py: New file.

2 files changed, 245 insertions, 0 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 1a5bafc..4ba426e 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,7 @@
+2010-01-06  Joel Brobecker  <brobecker@adacore.com>
+
+	* gdb-gdb.py: New file.
+
 2010-01-05  Michael Snyder  <msnyder@vmware.com>
 
 	* infrun.c (handle_inferior_event): Fix typo in comment.
diff --git a/gdb/gdb-gdb.py b/gdb/gdb-gdb.py
new file mode 100644
index 0000000..49695b5
--- /dev/null
+++ b/gdb/gdb-gdb.py
@@ -0,0 +1,241 @@
+# Copyright (C) 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/>.
+
+import gdb
+import os.path
+
+class TypeFlag:
+    """A class that allows us to store a flag name, its short name,
+    and its value.
+
+    In the GDB sources, struct type has a component called instance_flags
+    whose the value is the addition of various flags.  These flags are
+    defined by two emumerates: type_flag_value, and type_instance_flag_value.
+    This class helps us recreate a list with all these flags that is
+    easy to manipulate and sort.  Because all flag names start with either
+    TYPE_FLAG_ or TYPE_INSTANCE_FLAG_, a short_name attribute is provided
+    that strips this prefix.
+
+    ATTRIBUTES
+      name:  The enumeration name (eg: "TYPE_FLAG_UNSIGNED").
+      value: The associated value.
+      short_name: The enumeration name, with the suffix stripped.
+    """
+    def __init__(self, name, value):
+        self.name = name
+        self.value = value
+        self.short_name = name.replace("TYPE_FLAG_", '')
+        if self.short_name == name:
+            self.short_name = name.replace("TYPE_INSTANCE_FLAG_", '')
+    def __cmp__(self, other):
+        """Sort by value order."""
+        return self.value.__cmp__(other.value)
+
+# A list of all existing TYPE_FLAGS_* and TYPE_INSTANCE_FLAGS_*
+# enumerations, stored as TypeFlags objects.  Lazy-initialized.
+TYPE_FLAGS = None
+
+class TypeFlagsPrinter:
+    """A class that prints a decoded form of an instance_flags value.
+
+    This class uses a global named TYPE_FLAGS, which is a list of
+    all defined TypeFlag values.  Using a global allows us to compute
+    this list only once.
+
+    This class relies on a couple of enumeration types being defined.
+    If not, then printing of the instance_flag is going to be degraded,
+    but it's not a fatal error.
+    """
+    def __init__(self, val):
+        self.val = val
+    def __str__(self):
+        global TYPE_FLAGS
+        if TYPE_FLAGS is None:
+            self.init_TYPE_FLAGS()
+        if not self.val:
+            return "0"
+        if TYPE_FLAGS:
+            flag_list = [flag.short_name for flag in TYPE_FLAGS
+                         if self.val & flag.value]
+        else:
+            flag_list = ["???"]
+        return "0x%x [%s]" % (self.val, "|".join(flag_list))
+    def init_TYPE_FLAGS(self):
+        """Initialize the TYPE_FLAGS global as a list of TypeFlag objects.
+        This operation requires the search of a couple of enumeration types.
+        If not found, a warning is printed on stdout, and TYPE_FLAGS is
+        set to the empty list.
+
+        The resulting list is sorted by increasing value, to facilitate
+        printing of the list of flags used in an instance_flags value.
+        """
+        global TYPE_FLAGS
+        TYPE_FLAGS = []
+        try:
+            flags = gdb.lookup_type("enum type_flag_value")
+        except:
+            print "Warning: Cannot find enum type_flag_value type."
+            print "         `struct type' pretty-printer will be degraded"
+            return
+        try:
+            iflags = gdb.lookup_type("enum type_instance_flag_value")
+        except:
+            print "Warning: Cannot find enum type_instance_flag_value type."
+            print "         `struct type' pretty-printer will be degraded"
+            return
+        # Note: TYPE_FLAG_MIN is a duplicate of TYPE_FLAG_UNSIGNED,
+        # so exclude it from the list we are building.
+        TYPE_FLAGS = [TypeFlag(field.name, field.bitpos)
+                      for field in flags.fields()
+                      if field.name != 'TYPE_FLAG_MIN']
+        TYPE_FLAGS += [TypeFlag(field.name, field.bitpos)
+                       for field in iflags.fields()]
+        TYPE_FLAGS.sort()
+
+class StructTypePrettyPrinter:
+    """Pretty-print an object of type struct type"""
+    def __init__(self, val):
+        self.val = val
+    def to_string(self):
+        fields = []
+        fields.append("pointer_type = %s" % self.val['pointer_type'])
+        fields.append("reference_type = %s" % self.val['reference_type'])
+        fields.append("chain = %s" % self.val['reference_type'])
+        fields.append("instance_flags = %s"
+                      % TypeFlagsPrinter(self.val['instance_flags']))
+        fields.append("length = %d" % self.val['length'])
+        fields.append("main_type = %s" % self.val['main_type'])
+        return "\n{" + ",\n ".join(fields) + "}"
+
+class StructMainTypePrettyPrinter:
+    """Pretty-print an objet of type main_type"""
+    def __init__(self, val):
+        self.val = val
+    def flags_to_string(self):
+        """struct main_type contains a series of components that
+        are one-bit ints whose name start with "flag_".  For instance:
+        flag_unsigned, flag_stub, etc.  In essence, these components are
+        really boolean flags, and this method prints a short synthetic
+        version of the value of all these flags.  For instance, if
+        flag_unsigned and flag_static are the only components set to 1,
+        this function will return "unsigned|static".
+        """
+        fields = [field.name.replace("flag_", "")
+                  for field in self.val.type.fields()
+                  if field.name.startswith("flag_")
+                     and self.val[field.name]]
+        return "|".join(fields)
+    def owner_to_string(self):
+        """Return an image of component "owner".
+        """
+        if self.val['flag_objfile_owned'] != 0:
+            return "%s (objfile)" % self.val['owner']['objfile']
+        else:
+            return "%s (gdbarch)" % self.val['owner']['gdbarch']
+    def struct_field_location_img(self, field_val):
+        """Return an image of the loc component inside the given field
+        gdb.Value.
+        """
+        loc_val = field_val['loc']
+        loc_kind = str(field_val['loc_kind'])
+        if loc_kind == "FIELD_LOC_KIND_BITPOS":
+            return 'bitpos = %d' % loc_val['bitpos']
+        elif loc_kind == "FIELD_LOC_KIND_PHYSADDR":
+            return 'physaddr = 0x%x' % loc_val['physaddr']
+        elif loc_kind == "FIELD_LOC_KIND_PHYSNAME":
+            return 'physname = %s' % loc_val['physname']
+        elif loc_kind == "FIELD_LOC_KIND_DWARF_BLOCK":
+            return 'dwarf_block = %s' % loc_val['dwarf_block']
+        else:
+            return 'loc = ??? (unsupported loc_kind value)'
+    def struct_field_img(self, fieldno):
+        """Return an image of the main_type field number FIELDNO.
+        """
+        f = self.val['flds_bnds']['fields'][fieldno]
+        label = "field[%d]:" % fieldno
+        if f['artificial']:
+            label += " (artificial)"
+        fields = []
+        fields.append("name = %s" % f['name'])
+        fields.append("type = %s" % f['type'])
+        fields.append("loc_kind = %s" % f['loc_kind'])
+        fields.append("bitsize = %d" % f['bitsize'])
+        fields.append(self.struct_field_location_img(f))
+        return label + "\n" + "  {" + ",\n   ".join(fields) + "}"
+    def bounds_img(self):
+        """Return an image of the main_type bounds.
+        """
+        b = self.val['flds_bnds']['bounds'].dereference()
+        low = str(b['low'])
+        if b['low_undefined'] != 0:
+            low += " (undefined)"
+        high = str(b['high'])
+        if b['high_undefined'] != 0:
+            high += " (undefined)"
+        return "bounds = {%s, %s}" % (low, high)
+    def to_string(self):
+        """Return a pretty-printed image of our main_type.
+        """
+        fields = []
+        fields.append("name = %s" % self.val['name'])
+        fields.append("tag_name = %s" % self.val['tag_name'])
+        fields.append("code = %s" % self.val['code'])
+        fields.append("flags = [%s]" % self.flags_to_string())
+        fields.append("owner = %s" % self.owner_to_string())
+        fields.append("target_type = %s" % self.val['target_type'])
+        fields.append("vptr_basetype = %s" % self.val['vptr_basetype'])
+        if self.val['nfields'] > 0:
+            for fieldno in range(self.val['nfields']):
+                fields.append("field[%d]:")
+                fields.append(self.struct_field_img(fieldno))
+        if self.val.type.code == gdb.TYPE_CODE_RANGE:
+            fields.append(self.bounds_img())
+        # FIXME: We need to print the type_specific field as well.
+        # But I will wait for a patch that introduces a discriminant.
+        # This will simplify the selection of the right component in
+        # that union.
+        return "\n{" + ",\n ".join(fields) + "}"
+
+def type_lookup_function(val):
+    """A routine that returns the correct pretty printer for VAL
+    if appropriate.  Returns None otherwise.
+    """
+    if val.type.tag == "type":
+        return StructTypePrettyPrinter(val)
+    elif val.type.tag == "main_type":
+        return StructMainTypePrettyPrinter(val)
+    return None
+
+def register_pretty_printer(objfile):
+    """A routine to register a pretty-printer against the given OBJFILE.
+    """
+    objfile.pretty_printers.append(type_lookup_function)
+
+if __name__ == "__main__":
+    if gdb.current_objfile() is not None:
+        # This is the case where this script is being "auto-loaded"
+        # for a given objfile.  Register the pretty-printer for that
+        # objfile.
+        register_pretty_printer(gdb.current_objfile())
+    else:
+        # We need to locate the objfile corresponding to the GDB
+        # executable, and register the pretty-printer for that objfile.
+        # FIXME: The condition used to match the objfile is too simplistic
+        # and will not work on Windows.
+        for objfile in gdb.objfiles():
+            if os.path.basename(objfile.filename) == "gdb":
+                objfile.pretty_printers.append(type_lookup_function)