]> git.ipfire.org Git - thirdparty/gcc.git/commitdiff
libstdc++: Fix std::deque::size() Xmethod [PR112491]
authorJonathan Wakely <jwakely@redhat.com>
Tue, 14 Nov 2023 15:08:13 +0000 (15:08 +0000)
committerJonathan Wakely <jwakely@redhat.com>
Tue, 14 Nov 2023 22:40:17 +0000 (22:40 +0000)
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.

(cherry picked from commit 4db820928065eccbeb725406450d826186582b9f)

libstdc++-v3/python/libstdcxx/v6/xmethods.py
libstdc++-v3/testsuite/libstdc++-xmethods/deque.cc

index c627f8ba8000375371befdb4f33fda14d5ce23d8..4e9ac150ba066ec03e64ac6949250b14c584b639 100644 (file)
@@ -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']
index fbb053fef917ac9f8da8090a53e74ae09e4361f1..646d00f9cbda94bd0a9fa50d3297107489d4d998 100644 (file)
@@ -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
 }