Disable avx2 python extension due to colab crash

Related issue: #432

glue/python/src/stim/__init__.py

@@ -8,10 +8,11 @@
 import stim._detect_machine_architecture as _tmp
 
 _tmp = _tmp._UNSTABLE_detect_march()
-if _tmp == 'avx2':
-    from stim._stim_avx2 import *
-    from stim._stim_avx2 import _UNSTABLE_raw_gate_data, _UNSTABLE_raw_format_data, __version__
-elif _tmp == 'sse2':
+# NOTE: avx2 disabled until https://github.com/quantumlib/Stim/issues/432 is fixed
+# if _tmp == 'avx2':
+#     from stim._stim_avx2 import *
+#     from stim._stim_avx2 import _UNSTABLE_raw_gate_data, _UNSTABLE_raw_format_data, __version__
+if _tmp == 'avx2' or _tmp == 'sse2':
     from stim._stim_sse2 import *
     from stim._stim_sse2 import _UNSTABLE_raw_gate_data, _UNSTABLE_raw_format_data, __version__
 else:

setup.py

@@ -68,18 +68,20 @@
         '-DSTIM_PYBIND11_MODULE_NAME=_stim_sse2',
     ],
 )
-stim_avx2 = Extension(
-    'stim._stim_avx2',
-    sources=RELEVANT_SOURCE_FILES,
-    include_dirs=[pybind11.get_include(), "src"],
-    language='c++',
-    extra_compile_args=[
-        *common_compile_args,
-        '-msse2',
-        '-mavx2',
-        '-DSTIM_PYBIND11_MODULE_NAME=_stim_avx2',
-    ],
-)
+
+# NOTE: disabled until https://github.com/quantumlib/Stim/issues/432 is fixed
+# stim_avx2 = Extension(
+#     'stim._stim_avx2',
+#     sources=RELEVANT_SOURCE_FILES,
+#     include_dirs=[pybind11.get_include(), "src"],
+#     language='c++',
+#     extra_compile_args=[
+#         *common_compile_args,
+#         '-msse2',
+#         '-mavx2',
+#         '-DSTIM_PYBIND11_MODULE_NAME=_stim_avx2',
+#     ],
+# )
 
 with open('glue/python/README.md', encoding='UTF-8') as f:
     long_description = f.read()

src/stim/mem/monotonic_buffer.h

@@ -62,26 +62,40 @@ struct MonotonicBuffer {
         ensure_available(reserve);
     }
     ~MonotonicBuffer() {
-        for (auto &v : old_areas) {
-            free(v.ptr_start);
+        std::vector<PointerRange<T>> to_delete_old = std::move(old_areas);
+        T *to_delete_cur = cur.ptr_start;
+
+        old_areas.clear();
+        cur.ptr_start = nullptr;
+        cur.ptr_end = nullptr;
+        tail.ptr_start = nullptr;
+        tail.ptr_end = nullptr;
+
+        for (const auto &old : to_delete_old) {
+            free(old.ptr_start);
         }
-        if (cur.ptr_start) {
-            free(cur.ptr_start);
+        if (to_delete_cur != nullptr) {
+            free(to_delete_cur);
         }
-        old_areas.clear();
-        cur.ptr_start = cur.ptr_end = tail.ptr_start = tail.ptr_end = nullptr;
     }
     MonotonicBuffer(MonotonicBuffer &&other) noexcept
         : tail(other.tail), cur(other.cur), old_areas(std::move(other.old_areas)) {
         other.cur.ptr_start = nullptr;
         other.cur.ptr_end = nullptr;
         other.tail.ptr_start = nullptr;
         other.tail.ptr_end = nullptr;
+        other.old_areas.clear();
     }
     MonotonicBuffer(const MonotonicBuffer &other) = delete;
     MonotonicBuffer &operator=(MonotonicBuffer &&other) noexcept {
-        (*this).~MonotonicBuffer();
-        new (this) MonotonicBuffer(std::move(other));
+        tail = other.tail;
+        cur = other.cur;
+        old_areas = std::move(other.old_areas);
+        other.cur.ptr_start = nullptr;
+        other.cur.ptr_end = nullptr;
+        other.tail.ptr_start = nullptr;
+        other.tail.ptr_end = nullptr;
+        other.old_areas.clear();
         return *this;
     }