Various minor fixes for python 3

Switch StdTuple printer from python 2-style "next" to python 3. Nested iteration changed enough to make the original bitset iteration code a bit trickier than it needs to be, so unnest. The end node of a map iterator is sometimes hard to detect in isolation, don't fail in that case. Differential Revision: https://reviews.llvm.org/D96167 (cherry picked from commit a34b8b8)

Author: Sterling-Augustine

libcxx/test/libcxx/gdb/gdb_pretty_printer_test.sh.cpp

@@ -489,8 +489,9 @@ void map_iterator_test() {
 
  auto not_found = one_two_three.find(7);
  MarkAsLive(not_found);
- CompareExpressionPrettyPrintToRegex("not_found",
- R"(std::__map_iterator = {\[0x[a-f0-9]+\] = end\(\)})");
+ // Because the end_node is not easily detected, just be sure it doesn't crash.
+ CompareExpressionPrettyPrintToRegex(
+ "not_found", R"(std::__map_iterator ( = {\[0x[a-f0-9]+\] = .*}|<error reading variable:.*>))");
 }
 
 void unordered_set_test() {

libcxx/utils/gdb/libcxx/printers.py

@@ -13,6 +13,7 @@
 
 from __future__ import print_function
 
+import math
 import re
 import gdb
 
@@ -141,7 +142,7 @@ def __iter__(self):
 
  def __next__(self):
  # child_iter raises StopIteration when appropriate.
- field_name = self.child_iter.next()
+ field_name = next(self.child_iter)
  child = self.val["__base_"][field_name]["__value_"]
  self.count += 1
  return ("[%d]" % self.count, child)
@@ -425,6 +426,7 @@ def __init__(self, val):
  self.val = val
  self.n_words = int(self.val["__n_words"])
  self.bits_per_word = int(self.val["__bits_per_word"])
+ self.bit_count = self.val.type.template_argument(0)
  if self.n_words == 1:
  self.values = [int(self.val["__first_"])]
  else:
@@ -435,21 +437,12 @@ def to_string(self):
  typename = _prettify_typename(self.val.type)
  return "%s" % typename
 
- def _byte_it(self, value):
- index = -1
- while value:
- index += 1
- will_yield = value % 2
- value /= 2
- if will_yield:
- yield index
-
  def _list_it(self):
- for word_index in range(self.n_words):
- current = self.values[word_index]
- if current:
-  for n in self._byte_it(current):
-  yield ("[%d]" % (word_index * self.bits_per_word + n), 1)
+ for bit in range(self.bit_count):
+ word = math.floor(bit / self.bits_per_word)
+ word_bit = bit % self.bits_per_word
+ if self.values[word] & (1 << word_bit):
+ yield ("[%d]" % bit, 1)
 
  def __iter__(self):
  return self._list_it()