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authorJonathan Wakely <jwakely@redhat.com>2023-11-14 15:08:13 +0000
committerJonathan Wakely <jwakely@redhat.com>2023-11-14 15:55:03 +0000
commit4db820928065eccbeb725406450d826186582b9f (patch)
tree55ec98541bfc20cacd745ada48856d24a75ad6a6
parent8f331be42991aa4d58ac770faf993accfcce882b (diff)
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libstdc++: Fix std::deque::size() Xmethod [PR112491]
The Xmethod for std::deque::size() assumed that the first element would be at the start of the first node. That's only true if elements are only added at the back. If an element is inserted at the front, or removed from the front (or anywhere before the middle) then the first node will not be completely populated, and the Xmethod will give the wrong result. libstdc++-v3/ChangeLog: PR libstdc++/112491 * python/libstdcxx/v6/xmethods.py (DequeWorkerBase.size): Fix calculation to use _M_start._M_cur. * testsuite/libstdc++-xmethods/deque.cc: Check failing cases.
-rw-r--r--libstdc++-v3/python/libstdcxx/v6/xmethods.py13
-rw-r--r--libstdc++-v3/testsuite/libstdc++-xmethods/deque.cc20
2 files changed, 28 insertions, 5 deletions
diff --git a/libstdc++-v3/python/libstdcxx/v6/xmethods.py b/libstdc++-v3/python/libstdcxx/v6/xmethods.py
index 42e60eb..dcef285 100644
--- a/libstdc++-v3/python/libstdcxx/v6/xmethods.py
+++ b/libstdc++-v3/python/libstdcxx/v6/xmethods.py
@@ -193,11 +193,14 @@ class DequeWorkerBase(gdb.xmethod.XMethodWorker):
self._bufsize = 512 // val_type.sizeof or 1
def size(self, obj):
- first_node = obj['_M_impl']['_M_start']['_M_node']
- last_node = obj['_M_impl']['_M_finish']['_M_node']
- cur = obj['_M_impl']['_M_finish']['_M_cur']
- first = obj['_M_impl']['_M_finish']['_M_first']
- return (last_node - first_node) * self._bufsize + (cur - first)
+ start = obj['_M_impl']['_M_start']
+ finish = obj['_M_impl']['_M_finish']
+ if not start['_M_node']:
+ return 0
+ return (self._bufsize
+ * (finish['_M_node'] - start['_M_node'] - 1)
+ + (finish['_M_cur'] - finish['_M_first'])
+ + (start['_M_last'] - start['_M_cur']))
def index(self, obj, idx):
first_node = obj['_M_impl']['_M_start']['_M_node']
diff --git a/libstdc++-v3/testsuite/libstdc++-xmethods/deque.cc b/libstdc++-v3/testsuite/libstdc++-xmethods/deque.cc
index 2d7e846..e4077c1 100644
--- a/libstdc++-v3/testsuite/libstdc++-xmethods/deque.cc
+++ b/libstdc++-v3/testsuite/libstdc++-xmethods/deque.cc
@@ -67,6 +67,26 @@ main ()
// { dg-final { whatis-test q1.back() int } }
// { dg-final { whatis-test q3\[0\] int } }
+ // PR libstdc++/112491
+ std::deque<int> q5;
+ q5.push_front(0);
+// { dg-final { note-test q5.size() 1 } }
+ std::deque<int> q6 = q1;
+ q6.pop_front();
+// { dg-final { note-test {q6.size() == (q1_size-1)} true } }
+ std::deque<int> q7 = q2;
+ q7.pop_front();
+ q7.pop_front();
+// { dg-final { note-test {q7.size() == (q2_size-2)} true } }
+ std::deque<int> q8 = q3;
+ q8.pop_front();
+ q8.pop_front();
+ q8.pop_front();
+// { dg-final { note-test {q8.size() == (q3_size-3)} true } }
+ std::deque<int> q9 = q8;
+ q9.clear();
+// { dg-final { note-test q9.size() 0 } }
+
return 0; // Mark SPOT
}