gh-90815: Add mimalloc memory allocator (#109914)

* Add mimalloc v2.12

Modified src/alloc.c to remove include of alloc-override.c and not
compile new handler.

Did not include the following files:

 - include/mimalloc-new-delete.h
 - include/mimalloc-override.h
 - src/alloc-override-osx.c
 - src/alloc-override.c
 - src/static.c
 - src/region.c

mimalloc is thread safe and shares a single heap across all runtimes,
therefore finalization and getting global allocated blocks across all
runtimes is different.

* mimalloc: minimal changes for use in Python:

 - remove debug spam for freeing large allocations
 - use same bytes (0xDD) for freed allocations in CPython and mimalloc
   This is important for the test_capi debug memory tests

* Don't export mimalloc symbol in libpython.
* Enable mimalloc as Python allocator option.
* Add mimalloc MIT license.
* Log mimalloc in Lib/test/pythoninfo.py.
* Document new mimalloc support.
* Use macro defs for exports as done in:
  https://github.com/python/cpython/pull/31164/

Co-authored-by: Sam Gross <colesbury@gmail.com>
Co-authored-by: Christian Heimes <christian@python.org>
Co-authored-by: Victor Stinner <vstinner@python.org>

1 files changed, 10 insertions, 3 deletions

diff --git a/Tools/build/smelly.py b/Tools/build/smelly.py
index ab34530..7c53426 100755
--- a/Tools/build/smelly.py
+++ b/Tools/build/smelly.py
@@ -11,6 +11,11 @@ ALLOWED_PREFIXES = ('Py', '_Py')
 if sys.platform == 'darwin':
     ALLOWED_PREFIXES += ('__Py',)
 
+# mimalloc doesn't use static, but it's symbols are not exported
+# from the shared library.  They do show up in the static library
+# before its linked into an executable.
+ALLOWED_STATIC_PREFIXES = ('mi_', '_mi_')
+
 # "Legacy": some old symbols are prefixed by "PY_".
 EXCEPTIONS = frozenset({
     'PY_TIMEOUT_MAX',
@@ -59,7 +64,7 @@ def get_exported_symbols(library, dynamic=False):
     return stdout
 
 
-def get_smelly_symbols(stdout):
+def get_smelly_symbols(stdout, dynamic=False):
     smelly_symbols = []
     python_symbols = []
     local_symbols = []
@@ -77,7 +82,9 @@ def get_smelly_symbols(stdout):
         symbol = parts[-1]
         result = '%s (type: %s)' % (symbol, symtype)
 
-        if symbol.startswith(ALLOWED_PREFIXES) or symbol in EXCEPTIONS:
+        if (symbol.startswith(ALLOWED_PREFIXES) or
+            symbol in EXCEPTIONS or
+            (not dynamic and symbol.startswith(ALLOWED_STATIC_PREFIXES))):
             python_symbols.append(result)
             continue
 
@@ -95,7 +102,7 @@ def get_smelly_symbols(stdout):
 
 def check_library(library, dynamic=False):
     nm_output = get_exported_symbols(library, dynamic)
-    smelly_symbols, python_symbols = get_smelly_symbols(nm_output)
+    smelly_symbols, python_symbols = get_smelly_symbols(nm_output, dynamic)
 
     if not smelly_symbols:
         print(f"OK: no smelly symbol found ({len(python_symbols)} Python symbols)")