[PATCH v3 3/3] Port libstdc++ pretty-printers to Python 2 + Python 3

Samuel Bronson
2014-07-11T03:45:38Z

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Loosely based on Matthias Klose's earlier patch
<http://patchwork.ozlabs.org/patch/287368/>.

This time with his name spelled correctly; sorry about that!

Tested with:

$ make check-target-libstdc++-v3 RUNTESTFLAGS='--directory libstdc++-prettyprinters'

libstdc++-v3/

PR libstdc++/58962
* python/libstdcxx/v6/printers.py: Port to Python 2+3
(imap): New compat function.
(izip): Likewise.
(Iterator): New mixin to allow writing iterators in Python 3 style
regardless of which version we're running on.
[Python3] (long) New compat alias for "int".
* testsuite/lib/gdb-test.exp: Port to Python 2+3 (print syntax)

Signed-off-by: Matthias Klose <doko@ubuntu.com>
Signed-off-by: Samuel Bronson <naesten@gmail.com>
---
libstdc++-v3/python/libstdcxx/v6/printers.py | 110 +++++++++++++++++++--------
libstdc++-v3/testsuite/lib/gdb-test.exp | 4 +-
2 files changed, 79 insertions(+), 35 deletions(-)

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diff --git a/libstdc++-v3/python/libstdcxx/v6/printers.py b/libstdc++-v3/python/libstdcxx/v6/printers.py
index 623a815..313b08d 100644
--- a/libstdc++-v3/python/libstdcxx/v6/printers.py
+++ b/libstdc++-v3/python/libstdcxx/v6/printers.py
@@ -1,4 +1,4 @@
-# Pretty-printers for libstc++.
+# Pretty-printers for libstdc++.

# Copyright (C) 2008-2014 Free Software Foundation, Inc.

@@ -18,6 +18,50 @@
import gdb
import itertools
import re
+import sys
+
+### Python 2 + Python 3 compatability code
+
+# Resources about compatability:
+#
+# * <http://pythonhosted.org/six/>: Documentation of the "six" module
+
+# FIXME: The handling of e.g. std::basic_string (at least on char)
+# probably needs updating to work with Python 3's new string rules.
+#
+# In particular, Python 3 has a separate type (called byte) for
+# bytestrings, and a special b"" syntax for the byte literals; the old
+# str() type has been redefined to always store Unicode text.
+#
+# We probably can't do much about this until GDB get their act
+# together: <https://sourceware.org/bugzilla/show_bug.cgi?id=17138>
+
+if sys.version_info[0] > 2:
+ ### Python 3 stuff
+ Iterator = object
+ # Python 3 folds these into the normal functions.
+ imap = map
+ izip = zip
+ # Also, int subsumes long
+ long = int
+else:
+ ### Python 2 stuff
+ class Iterator:
+ """Compatability mixin for iterators
+
+ Instead of writing next() methods for iterators, write
+ __next__() methods and use this mixin to make them work in
+ Python 2 as well as Python 3.
+
+ Idea stolen from the "six" documentation:
+ <http://pythonhosted.org/six/#six.Iterator>
+ """
+
+ def next(self):
+ return self.__next__()
+
+ # In Python 2, we still need these from itertools
+ from itertools import imap, izip

# Try to use the new-style pretty-printing if available.
_use_gdb_pp = True
@@ -87,7 +131,7 @@ class UniquePointerPrinter:
class StdListPrinter:
"Print a std::list"

- class _iterator:
+ class _iterator(Iterator):
def __init__(self, nodetype, head):
self.nodetype = nodetype
self.base = head['_M_next']
@@ -97,7 +141,7 @@ class StdListPrinter:
def __iter__(self):
return self

- def next(self):
+ def __next__(self):
if self.base == self.head:
raise StopIteration
elt = self.base.cast(self.nodetype).dereference()
@@ -135,7 +179,7 @@ class StdListIteratorPrinter:
class StdSlistPrinter:
"Print a __gnu_cxx::slist"

- class _iterator:
+ class _iterator(Iterator):
def __init__(self, nodetype, head):
self.nodetype = nodetype
self.base = head['_M_head']['_M_next']
@@ -144,7 +188,7 @@ class StdSlistPrinter:
def __iter__(self):
return self

- def next(self):
+ def __next__(self):
if self.base == 0:
raise StopIteration
elt = self.base.cast(self.nodetype).dereference()
@@ -180,7 +224,7 @@ class StdSlistIteratorPrinter:
class StdVectorPrinter:
"Print a std::vector"

- class _iterator:
+ class _iterator(Iterator):
def __init__ (self, start, finish, bitvec):
self.bitvec = bitvec
if bitvec:
@@ -198,7 +242,7 @@ class StdVectorPrinter:
def __iter__(self):
return self

- def next(self):
+ def __next__(self):
count = self.count
self.count = self.count + 1
if self.bitvec:
@@ -265,7 +309,7 @@ class StdVectorIteratorPrinter:
class StdTuplePrinter:
"Print a std::tuple"

- class _iterator:
+ class _iterator(Iterator):
def __init__ (self, head):
self.head = head

@@ -282,7 +326,7 @@ class StdTuplePrinter:
def __iter__ (self):
return self

- def next (self):
+ def __next__ (self):
nodes = self.head.type.fields ()
# Check for further recursions in the inheritance tree.
if len (nodes) == 0:
@@ -341,7 +385,7 @@ class StdStackOrQueuePrinter:
return self.visualizer.display_hint ()
return None

-class RbtreeIterator:
+class RbtreeIterator(Iterator):
def __init__(self, rbtree):
self.size = rbtree['_M_t']['_M_impl']['_M_node_count']
self.node = rbtree['_M_t']['_M_impl']['_M_header']['_M_left']
@@ -353,7 +397,7 @@ class RbtreeIterator:
def __len__(self):
return int (self.size)

- def next(self):
+ def __next__(self):
if self.count == self.size:
raise StopIteration
result = self.node
@@ -422,7 +466,7 @@ class StdMapPrinter:
"Print a std::map or std::multimap"

# Turn an RbtreeIterator into a pretty-print iterator.
- class _iter:
+ class _iter(Iterator):
def __init__(self, rbiter, type):
self.rbiter = rbiter
self.count = 0
@@ -431,9 +475,9 @@ class StdMapPrinter:
def __iter__(self):
return self

- def next(self):
+ def __next__(self):
if self.count % 2 == 0:
- n = self.rbiter.next()
+ n = next(self.rbiter)
n = n.cast(self.type).dereference()
n = get_value_from_Rb_tree_node(n)
self.pair = n
@@ -465,7 +509,7 @@ class StdSetPrinter:
"Print a std::set or std::multiset"

# Turn an RbtreeIterator into a pretty-print iterator.
- class _iter:
+ class _iter(Iterator):
def __init__(self, rbiter, type):
self.rbiter = rbiter
self.count = 0
@@ -474,8 +518,8 @@ class StdSetPrinter:
def __iter__(self):
return self

- def next(self):
- item = self.rbiter.next()
+ def __next__(self):
+ item = next(self.rbiter)
item = item.cast(self.type).dereference()
item = get_value_from_Rb_tree_node(item)
# FIXME: this is weird ... what to do?
@@ -541,7 +585,7 @@ class StdBitsetPrinter:
class StdDequePrinter:
"Print a std::deque"

- class _iter:
+ class _iter(Iterator):
def __init__(self, node, start, end, last, buffer_size):
self.node = node
self.p = start
@@ -553,7 +597,7 @@ class StdDequePrinter:
def __iter__(self):
return self

- def next(self):
+ def __next__(self):
if self.p == self.last:
raise StopIteration

@@ -638,7 +682,7 @@ class StdStringPrinter:
def display_hint (self):
return 'string'

-class Tr1HashtableIterator:
+class Tr1HashtableIterator(Iterator):
def __init__ (self, hash):
self.buckets = hash['_M_buckets']
self.bucket = 0
@@ -654,7 +698,7 @@ class Tr1HashtableIterator:
def __iter__ (self):
return self

- def next (self):
+ def __next__ (self):
if self.node == 0:
raise StopIteration
node = self.node.cast(self.node_type)
@@ -669,7 +713,7 @@ class Tr1HashtableIterator:
self.bucket = self.bucket + 1
return result

-class StdHashtableIterator:
+class StdHashtableIterator(Iterator):
def __init__(self, hash):
self.node = hash['_M_before_begin']['_M_nxt']
self.node_type = find_type(hash.type, '__node_type').pointer()
@@ -677,7 +721,7 @@ class StdHashtableIterator:
def __iter__(self):
return self

- def next(self):
+ def __next__(self):
if self.node == 0:
raise StopIteration
elt = self.node.cast(self.node_type).dereference()
@@ -706,10 +750,10 @@ class Tr1UnorderedSetPrinter:
return '[%d]' % i

def children (self):
- counter = itertools.imap (self.format_count, itertools.count())
+ counter = imap (self.format_count, itertools.count())
if self.typename.startswith('std::tr1'):
- return itertools.izip (counter, Tr1HashtableIterator (self.hashtable()))
- return itertools.izip (counter, StdHashtableIterator (self.hashtable()))
+ return izip (counter, Tr1HashtableIterator (self.hashtable()))
+ return izip (counter, StdHashtableIterator (self.hashtable()))

class Tr1UnorderedMapPrinter:
"Print a tr1::unordered_map"
@@ -741,15 +785,15 @@ class Tr1UnorderedMapPrinter:
return '[%d]' % i

def children (self):
- counter = itertools.imap (self.format_count, itertools.count())
+ counter = imap (self.format_count, itertools.count())
# Map over the hash table and flatten the result.
if self.typename.startswith('std::tr1'):
- data = self.flatten (itertools.imap (self.format_one, Tr1HashtableIterator (self.hashtable())))
+ data = self.flatten (imap (self.format_one, Tr1HashtableIterator (self.hashtable())))
# Zip the two iterators together.
- return itertools.izip (counter, data)
- data = self.flatten (itertools.imap (self.format_one, StdHashtableIterator (self.hashtable())))
+ return izip (counter, data)
+ data = self.flatten (imap (self.format_one, StdHashtableIterator (self.hashtable())))
# Zip the two iterators together.
- return itertools.izip (counter, data)
+ return izip (counter, data)

def display_hint (self):
@@ -758,7 +802,7 @@ class Tr1UnorderedMapPrinter:
class StdForwardListPrinter:
"Print a std::forward_list"

- class _iterator:
+ class _iterator(Iterator):
def __init__(self, nodetype, head):
self.nodetype = nodetype
self.base = head['_M_next']
@@ -767,7 +811,7 @@ class StdForwardListPrinter:
def __iter__(self):
return self

- def next(self):
+ def __next__(self):
if self.base == 0:
raise StopIteration
elt = self.base.cast(self.nodetype).dereference()
diff --git a/libstdc++-v3/testsuite/lib/gdb-test.exp b/libstdc++-v3/testsuite/lib/gdb-test.exp
index 6d7ea9d..9cb6ecf 100644
--- a/libstdc++-v3/testsuite/lib/gdb-test.exp
+++ b/libstdc++-v3/testsuite/lib/gdb-test.exp
@@ -91,7 +91,7 @@ proc gdb-test { marker {selector {}} } {
}
}

- set do_whatis_tests [gdb_batch_check "python print gdb.type_printers" \
+ set do_whatis_tests [gdb_batch_check "python print(gdb.type_printers)" \
"\\\[\\\]"]
if {!$do_whatis_tests} {
send_log "skipping 'whatis' tests - gdb too old"
@@ -259,6 +259,6 @@ proc gdb_batch_check {command pattern} {
# but not earlier versions.
# Return 1 if the version is ok, 0 otherwise.
proc gdb_version_check {} {
- return [gdb_batch_check "python print gdb.lookup_global_symbol" \
+ return [gdb_batch_check "python print(gdb.lookup_global_symbol)" \
"<built-in function lookup_global_symbol>"]
}