Changes made in sprint for PLDI deadline.

.github/workflows/build.yml

@@ -168,10 +168,11 @@ jobs:
           - arm64
         free-threading:
           - false
-          - true
-        exclude:
-          # Skip Win32 on free-threaded builds
-          - { arch: Win32, free-threading: true }
+        # TODO(Immutable): Enable free-threading build when it is made to work.
+        #        - true
+        # exclude:
+        #   # Skip Win32 on free-threaded builds
+        #   - { arch: Win32, free-threading: true }
     uses: ./.github/workflows/reusable-windows.yml
     with:
       arch: ${{ matrix.arch }}
@@ -209,10 +210,11 @@ jobs:
         - macos-15-intel
         free-threading:
         - false
-        - true
-        exclude:
-        - os: macos-15-intel
-          free-threading: true
+        # TODO(Immutable): Enable free-threading build when it is made to work.
+        #        - true
+        # exclude:
+        # - os: macos-15-intel
+        #   free-threading: true
     uses: ./.github/workflows/reusable-macos.yml
     with:
       config_hash: ${{ needs.build-context.outputs.config-hash }}
@@ -234,14 +236,15 @@ jobs:
         - true
         free-threading:
         - false
-        - true
+        # TODO(Immutable): Enable free-threading build when it is made to work.
+        #        - true
         os:
         - ubuntu-24.04
         - ubuntu-24.04-arm
         exclude:
-        # Do not test BOLT with free-threading, to conserve resources
-        - bolt: true
-          free-threading: true
+        # # Do not test BOLT with free-threading, to conserve resources
+        # - bolt: true
+        #   free-threading: true
         # BOLT currently crashes during instrumentation on aarch64
         - os: ubuntu-24.04-arm
           bolt: true
@@ -614,13 +617,14 @@ jobs:
         - Thread
         free-threading:
         - false
-        - true
+        # TODO(Immutable): Enable free-threading build when it is made to work.
+        #        - true
         sanitizer:
         - TSan
-        include:
-        - check-name: Undefined behavior
-          sanitizer: UBSan
-          free-threading: false
+        # include:
+        # - check-name: Undefined behavior
+        #   sanitizer: UBSan
+        #   free-threading: false
     uses: ./.github/workflows/reusable-san.yml
     with:
       sanitizer: ${{ matrix.sanitizer }}

.github/workflows/jit.yml

@@ -129,33 +129,33 @@ jobs:
           make all --jobs 4
           ./python -m test --multiprocess 0 --timeout 4500 --verbose2 --verbose3
 
-  jit-with-disabled-gil:
-    name: Free-Threaded (Debug)
-    needs: interpreter
-    runs-on: ubuntu-24.04
-    timeout-minutes: 90
-    strategy:
-      fail-fast: false
-      matrix:
-        llvm:
-          - 19
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
-      - uses: actions/setup-python@v5
-        with:
-          python-version: '3.11'
-      - name: Build with JIT enabled and GIL disabled
-        run: |
-          sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" ./llvm.sh ${{ matrix.llvm }}
-          export PATH="$(llvm-config-${{ matrix.llvm }} --bindir):$PATH"
-          ./configure --enable-experimental-jit --with-pydebug --disable-gil
-          make all --jobs 4
-      - name: Run tests
-        run: |
-          ./python -m test --multiprocess 0 --timeout 4500 --verbose2 --verbose3
-        continue-on-error: true
+  # jit-with-disabled-gil:
+  #   name: Free-Threaded (Debug)
+  #   needs: interpreter
+  #   runs-on: ubuntu-24.04
+  #   timeout-minutes: 90
+  #   strategy:
+  #     fail-fast: false
+  #     matrix:
+  #       llvm:
+  #         - 19
+  #   steps:
+  #     - uses: actions/checkout@v4
+  #       with:
+  #         persist-credentials: false
+  #     - uses: actions/setup-python@v5
+  #       with:
+  #         python-version: '3.11'
+  #     - name: Build with JIT enabled and GIL disabled
+  #       run: |
+  #         sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" ./llvm.sh ${{ matrix.llvm }}
+  #         export PATH="$(llvm-config-${{ matrix.llvm }} --bindir):$PATH"
+  #         ./configure --enable-experimental-jit --with-pydebug --disable-gil
+  #         make all --jobs 4
+  #     - name: Run tests
+  #       run: |
+  #         ./python -m test --multiprocess 0 --timeout 4500 --verbose2 --verbose3
+  #       continue-on-error: true
 
   no-opt-jit:
     name: JIT without optimizations (Debug)

.github/workflows/tail-call.yml

@@ -122,11 +122,11 @@ jobs:
           make all --jobs 4
           ./python -m test --multiprocess 0 --timeout 4500 --verbose2 --verbose3
 
-      - name: Native Linux with free-threading (release)
-        if: matrix.target == 'free-threading'
-        run: |
-          sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" ./llvm.sh ${{ matrix.llvm }}
-          export PATH="$(llvm-config-${{ matrix.llvm }} --bindir):$PATH"
-          CC=clang-20 ./configure --with-tail-call-interp --disable-gil
-          make all --jobs 4
-          ./python -m test --multiprocess 0 --timeout 4500 --verbose2 --verbose3
+      # - name: Native Linux with free-threading (release)
+      #   if: matrix.target == 'free-threading'
+      #   run: |
+      #     sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" ./llvm.sh ${{ matrix.llvm }}
+      #     export PATH="$(llvm-config-${{ matrix.llvm }} --bindir):$PATH"
+      #     CC=clang-20 ./configure --with-tail-call-interp --disable-gil
+      #     make all --jobs 4
+      #     ./python -m test --multiprocess 0 --timeout 4500 --verbose2 --verbose3

Include/internal/pycore_freelist_state.h

@@ -8,29 +8,33 @@ extern "C" {
 #  error "this header requires Py_BUILD_CORE define"
 #endif
 
+#define MAXFREELIST(x) x
+//#define MAXFREELIST(x) 0
+
+
 #  define PyTuple_MAXSAVESIZE 20     // Largest tuple to save on freelist
-#  define Py_tuple_MAXFREELIST 2000  // Maximum number of tuples of each size to save
-#  define Py_lists_MAXFREELIST 80
-#  define Py_list_iters_MAXFREELIST 10
-#  define Py_tuple_iters_MAXFREELIST 10
-#  define Py_dicts_MAXFREELIST 80
-#  define Py_dictkeys_MAXFREELIST 80
-#  define Py_floats_MAXFREELIST 100
-#  define Py_complexes_MAXFREELIST 100
-#  define Py_ints_MAXFREELIST 100
-#  define Py_slices_MAXFREELIST 1
-#  define Py_ranges_MAXFREELIST 6
-#  define Py_range_iters_MAXFREELIST 6
-#  define Py_contexts_MAXFREELIST 255
-#  define Py_async_gens_MAXFREELIST 80
-#  define Py_async_gen_asends_MAXFREELIST 80
-#  define Py_futureiters_MAXFREELIST 255
-#  define Py_object_stack_chunks_MAXFREELIST 4
-#  define Py_unicode_writers_MAXFREELIST 1
-#  define Py_bytes_writers_MAXFREELIST 1
-#  define Py_pycfunctionobject_MAXFREELIST 16
-#  define Py_pycmethodobject_MAXFREELIST 16
-#  define Py_pymethodobjects_MAXFREELIST 20
+#  define Py_tuple_MAXFREELIST MAXFREELIST(2000)  // Maximum number of tuples of each size to save
+#  define Py_lists_MAXFREELIST MAXFREELIST(80)
+#  define Py_list_iters_MAXFREELIST MAXFREELIST(10)
+#  define Py_tuple_iters_MAXFREELIST MAXFREELIST(10)
+#  define Py_dicts_MAXFREELIST MAXFREELIST(80)
+#  define Py_dictkeys_MAXFREELIST MAXFREELIST(80)
+#  define Py_floats_MAXFREELIST MAXFREELIST(100)
+#  define Py_complexes_MAXFREELIST MAXFREELIST(100)
+#  define Py_ints_MAXFREELIST MAXFREELIST(100)
+#  define Py_slices_MAXFREELIST MAXFREELIST(1)
+#  define Py_ranges_MAXFREELIST MAXFREELIST(6)
+#  define Py_range_iters_MAXFREELIST MAXFREELIST(6)
+#  define Py_contexts_MAXFREELIST MAXFREELIST(255)
+#  define Py_async_gens_MAXFREELIST MAXFREELIST(80)
+#  define Py_async_gen_asends_MAXFREELIST MAXFREELIST(80)
+#  define Py_futureiters_MAXFREELIST MAXFREELIST(255)
+#  define Py_object_stack_chunks_MAXFREELIST MAXFREELIST(4)
+#  define Py_unicode_writers_MAXFREELIST MAXFREELIST(1)
+#  define Py_bytes_writers_MAXFREELIST MAXFREELIST(1)
+#  define Py_pycfunctionobject_MAXFREELIST MAXFREELIST(16)
+#  define Py_pycmethodobject_MAXFREELIST MAXFREELIST(16)
+#  define Py_pymethodobjects_MAXFREELIST MAXFREELIST(20)
 
 // A generic freelist of either PyObjects or other data structures.
 struct _Py_freelist {

Include/internal/pycore_global_strings.h

@@ -121,6 +121,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(__floor__)
         STRUCT_FOR_ID(__floordiv__)
         STRUCT_FOR_ID(__format__)
+        STRUCT_FOR_ID(__freezable__)
         STRUCT_FOR_ID(__fspath__)
         STRUCT_FOR_ID(__ge__)
         STRUCT_FOR_ID(__get__)
@@ -186,6 +187,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(__path__)
         STRUCT_FOR_ID(__pos__)
         STRUCT_FOR_ID(__pow__)
+        STRUCT_FOR_ID(__pre_freeze__)
         STRUCT_FOR_ID(__prepare__)
         STRUCT_FOR_ID(__qualname__)
         STRUCT_FOR_ID(__radd__)

Include/internal/pycore_interp_structs.h

@@ -840,6 +840,7 @@ struct _is {
 
     // Dictionary of the sys module
     PyObject *sysdict;
+    PyObject *mutable_modules;
 
     // Dictionary of the builtins module
     PyObject *builtins;

Include/internal/pycore_list.h

@@ -64,6 +64,8 @@ _Py_memory_repeat(char* dest, Py_ssize_t len_dest, Py_ssize_t len_src)
     }
 }
 
+PyAPI_FUNC(PyObject*) _Py_ListPop(PyListObject *self, Py_ssize_t index);
+
 typedef struct {
     PyObject_HEAD
     Py_ssize_t it_index;

Include/internal/pycore_moduleobject.h

@@ -18,30 +18,50 @@ extern int _PyModule_IsExtension(PyObject *obj);
 
 typedef struct {
     PyObject_HEAD
+    // For immutable modules to find the mutable state and
+    // for logging purposes after md_dict is cleared
+    PyObject *md_name;
+    int md_frozen;
+
+    // *******************************************************
+    // Module state, only available on mutable module objects
+    // *******************************************************
     PyObject *md_dict;
     PyModuleDef *md_def;
     void *md_state;
     PyObject *md_weaklist;
-    // for logging purposes after md_dict is cleared
-    PyObject *md_name;
 #ifdef Py_GIL_DISABLED
     void *md_gil;
 #endif
 } PyModuleObject;
 
+PyAPI_FUNC(PyModuleObject*) _PyInterpreterState_GetModuleState(PyObject *mod);
+
 static inline PyModuleDef* _PyModule_GetDef(PyObject *mod) {
     assert(PyModule_Check(mod));
-    return ((PyModuleObject *)mod)->md_def;
+    PyModuleObject *state = _PyInterpreterState_GetModuleState(mod);
+    if (state == NULL) {
+        return NULL;
+    }
+    return state->md_def;
 }
 
 static inline void* _PyModule_GetState(PyObject* mod) {
     assert(PyModule_Check(mod));
-    return ((PyModuleObject *)mod)->md_state;
+    PyModuleObject *state = _PyInterpreterState_GetModuleState(mod);
+    if (state == NULL) {
+        return NULL;
+    }
+    return state->md_state;
 }
 
 static inline PyObject* _PyModule_GetDict(PyObject *mod) {
     assert(PyModule_Check(mod));
-    PyObject *dict = ((PyModuleObject *)mod) -> md_dict;
+    PyModuleObject *state = _PyInterpreterState_GetModuleState(mod);
+    if (state == NULL) {
+        return NULL;
+    }
+    PyObject *dict = state -> md_dict;
     // _PyModule_GetDict(mod) must not be used after calling module_clear(mod)
     assert(dict != NULL);
     return dict;  // borrowed reference
@@ -56,6 +76,8 @@ extern Py_ssize_t _PyModule_GetFilenameUTF8(
 PyObject* _Py_module_getattro_impl(PyModuleObject *m, PyObject *name, int suppress);
 PyObject* _Py_module_getattro(PyObject *m, PyObject *name);
 
+extern int _Py_module_freeze_hook(PyObject *m);
+
 #ifdef __cplusplus
 }
 #endif