Restored 32-bit support

.appveyor.yml

@@ -10,8 +10,8 @@ environment:
   TEST_OPTIONS:
   DEPLOY: YES
   matrix:
-  - PYTHON: C:/Python311-x64
-    ARCHITECTURE: x64
+  - PYTHON: C:/Python311
+    ARCHITECTURE: x86
     APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022
   - PYTHON: C:/Python38-x64
     ARCHITECTURE: x64

.github/workflows/test-docker.yml

@@ -39,6 +39,7 @@ jobs:
           centos-stream-8-amd64,
           centos-stream-9-amd64,
           debian-11-bullseye-amd64,
+          debian-12-bookworm-x86,
           debian-12-bookworm-amd64,
           fedora-37-amd64,
           fedora-38-amd64,

Tests/32bit_segfault_check.py

@@ -0,0 +1,8 @@
+#!/usr/bin/env python3
+
+import sys
+
+from PIL import Image
+
+if sys.maxsize < 2**32:
+    im = Image.new("L", (999999, 999999), 0)

Tests/check_large_memory.py

@@ -1,3 +1,5 @@
+import sys
+
 import pytest
 
 from PIL import Image
@@ -21,6 +23,9 @@
 XDIM = 48000
 
 
+pytestmark = pytest.mark.skipif(sys.maxsize <= 2**32, reason="requires 64-bit system")
+
+
 def _write_png(tmp_path, xdim, ydim):
     f = str(tmp_path / "temp.png")
     im = Image.new("L", (xdim, ydim), 0)

Tests/check_large_memory_numpy.py

@@ -1,3 +1,5 @@
+import sys
+
 import pytest
 
 from PIL import Image
@@ -17,6 +19,9 @@
 XDIM = 48000
 
 
+pytestmark = pytest.mark.skipif(sys.maxsize <= 2**32, reason="requires 64-bit system")
+
+
 def _write_png(tmp_path, xdim, ydim):
     dtype = np.uint8
     a = np.zeros((xdim, ydim), dtype=dtype)

Tests/test_core_resources.py

@@ -1,3 +1,5 @@
+import sys
+
 import pytest
 
 from PIL import Image
@@ -108,6 +110,9 @@ def test_set_blocks_max(self):
 
         with pytest.raises(ValueError):
             Image.core.set_blocks_max(-1)
+        if sys.maxsize < 2**32:
+            with pytest.raises(ValueError):
+                Image.core.set_blocks_max(2**29)
 
     @pytest.mark.skipif(is_pypy(), reason="Images not collected")
     def test_set_blocks_max_stats(self):

Tests/test_file_webp.py

@@ -1,5 +1,6 @@
 import io
 import re
+import sys
 import warnings
 
 import pytest
@@ -144,6 +145,7 @@ def test_write_unsupported_mode_P(self, tmp_path):
 
         self._roundtrip(tmp_path, "P", 50.0)
 
+    @pytest.mark.skipif(sys.maxsize <= 2**32, reason="Requires 64-bit system")
     def test_write_encoding_error_message(self, tmp_path):
         temp_file = str(tmp_path / "temp.webp")
         im = Image.new("RGB", (15000, 15000))

Tests/test_image_putdata.py

@@ -38,7 +38,10 @@ def put(value):
     assert put(0xFFFFFFFF) == (255, 255, 255, 255)
     assert put(-1) == (255, 255, 255, 255)
     assert put(-1) == (255, 255, 255, 255)
-    assert put(sys.maxsize) == (255, 255, 255, 255)
+    if sys.maxsize > 2**32:
+        assert put(sys.maxsize) == (255, 255, 255, 255)
+    else:
+        assert put(sys.maxsize) == (255, 255, 255, 127)
 
 
 def test_pypy_performance():

Tests/test_map.py

@@ -1,3 +1,5 @@
+import sys
+
 import pytest
 
 from PIL import Image
@@ -34,6 +36,7 @@ def test_tobytes():
     Image.MAX_IMAGE_PIXELS = max_pixels
 
 
+@pytest.mark.skipif(sys.maxsize <= 2**32, reason="Requires 64-bit system")
 def test_ysize():
     numpy = pytest.importorskip("numpy", reason="NumPy not installed")
 

codecov.yml

@@ -16,6 +16,7 @@ coverage:
 
 # Matches 'omit:' in .coveragerc
 ignore:
+  - "Tests/32bit_segfault_check.py"
   - "Tests/bench_cffi_access.py"
   - "Tests/check_*.py"
   - "Tests/createfontdatachunk.py"

docs/installation.rst

@@ -285,8 +285,11 @@ Many of Pillow's features require external libraries:
 
 .. tab:: Windows using MSYS2/MinGW
 
-    To build Pillow using MSYS2, make sure you run the **MSYS2 MinGW 64-bit** console,
-    *not* **MSYS2** directly.
+    To build Pillow using MSYS2, make sure you run the **MSYS2 MinGW 32-bit** or
+    **MSYS2 MinGW 64-bit** console, *not* **MSYS2** directly.
+
+    The following instructions target the 64-bit build, for 32-bit
+    replace all occurrences of ``mingw-w64-x86_64-`` with ``mingw-w64-i686-``.
 
     Make sure you have Python and GCC installed::
 
@@ -336,6 +339,8 @@ Many of Pillow's features require external libraries:
         pkg install -y python ndk-sysroot clang make \
             libjpeg-turbo
 
+    This has been tested within the Termux app on ChromeOS, on x86.
+
 Installing
 ^^^^^^^^^^
 
@@ -448,7 +453,7 @@ These platforms are built and tested for every change.
 +----------------------------------+----------------------------+---------------------+
 | Debian 11 Bullseye               | 3.9                        | x86-64              |
 +----------------------------------+----------------------------+---------------------+
-| Debian 12 Bookworm               | 3.11                       | x86-64              |
+| Debian 12 Bookworm               | 3.11                       | x86, x86-64         |
 +----------------------------------+----------------------------+---------------------+
 | Fedora 37                        | 3.11                       | x86-64              |
 +----------------------------------+----------------------------+---------------------+
@@ -472,6 +477,8 @@ These platforms are built and tested for every change.
 | Windows Server 2022              | 3.8, 3.9, 3.10, 3.11,      | x86-64              |
 |                                  | 3.12, PyPy3                |                     |
 |                                  +----------------------------+---------------------+
+|                                  | 3.11                       | x86                 |
+|                                  +----------------------------+---------------------+
 |                                  | 3.9 (MinGW)                | x86-64              |
 |                                  +----------------------------+---------------------+
 |                                  | 3.8, 3.9 (Cygwin)          | x86-64              |

docs/releasenotes/10.0.0.rst

@@ -4,11 +4,6 @@
 Backwards Incompatible Changes
 ==============================
 
-32-bit support
-^^^^^^^^^^^^^^
-
-32-bit architecture is no longer supported and 32-bit wheels are no longer provided.
-
 Categories
 ^^^^^^^^^^
 
@@ -129,14 +124,6 @@ Image.coerce_e
 
 This undocumented method has been removed.
 
-Deprecations
-============
-
-TODO
-^^^^
-
-TODO
-
 API Changes
 ===========
 
@@ -165,6 +152,11 @@ TODO
 Other Changes
 =============
 
+32-bit wheels
+^^^^^^^^^^^^^
+
+32-bit wheels are no longer provided.
+
 Support display_jpeg() in IPython
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 

setup.py

@@ -153,13 +153,16 @@ def _find_library_dirs_ldconfig():
 
     ldconfig = "ldconfig" if shutil.which("ldconfig") else "/sbin/ldconfig"
     if sys.platform.startswith("linux") or sys.platform.startswith("gnu"):
-        machine = os.uname()[4]
+        if struct.calcsize("l") == 4:
+            machine = os.uname()[4] + "-32"
+        else:
+            machine = os.uname()[4] + "-64"
         mach_map = {
-            "x86_64": "libc6,x86-64",
-            "ppc64": "libc6,64bit",
-            "sparc64": "libc6,64bit",
-            "s390x": "libc6,64bit",
-            "ia64": "libc6,IA-64",
+            "x86_64-64": "libc6,x86-64",
+            "ppc64-64": "libc6,64bit",
+            "sparc64-64": "libc6,64bit",
+            "s390x-64": "libc6,64bit",
+            "ia64-64": "libc6,IA-64",
         }
         abi_type = mach_map.get(machine, "libc6")
 
@@ -581,7 +584,10 @@ def build_extensions(self):
                 # user libs are at $PREFIX/lib
                 _add_directory(
                     library_dirs,
-                    os.path.join(os.environ["ANDROID_ROOT"], "lib64"),
+                    os.path.join(
+                        os.environ["ANDROID_ROOT"],
+                        "lib" if struct.calcsize("l") == 4 else "lib64",
+                    ),
                 )
 
         elif sys.platform.startswith("netbsd"):

src/libImaging/ImagingUtils.h

@@ -30,7 +30,7 @@
 /* This is to work around a bug in GCC prior 4.9 in 64 bit mode.
    GCC generates code with partial dependency which is 3 times slower.
    See: https://stackoverflow.com/a/26588074/253146 */
-#if defined(__SSE__) && !defined(__NO_INLINE__) && \
+#if defined(__x86_64__) && defined(__SSE__) && !defined(__NO_INLINE__) && \
     !defined(__clang__) && defined(GCC_VERSION) && (GCC_VERSION < 40900)
 static float __attribute__((always_inline)) inline _i2f(int v) {
     float x;

winbuild/build.rst

@@ -27,7 +27,7 @@ Download and install:
 * `Ninja <https://ninja-build.org/>`_
   (optional, use ``--nmake`` if not available; bundled in Visual Studio CMake component)
 
-* x64: `Netwide Assembler (NASM) <https://www.nasm.us/pub/nasm/releasebuilds/?C=M;O=D>`_
+* x86/x64: `Netwide Assembler (NASM) <https://www.nasm.us/pub/nasm/releasebuilds/?C=M;O=D>`_
 
 Any version of Visual Studio 2017 or newer should be supported,
 including Visual Studio 2017 Community, or Build Tools for Visual Studio 2019.
@@ -42,7 +42,7 @@ Run ``build_prepare.py`` to configure the build::
 
     usage: winbuild\build_prepare.py [-h] [-v] [-d PILLOW_BUILD]
                                      [--depends PILLOW_DEPS]
-                                     [--architecture {x64,ARM64}]
+                                     [--architecture {x86,x64,ARM64}]
                                      [--python PYTHON] [--executable EXECUTABLE]
                                      [--nmake] [--no-imagequant] [--no-fribidi]
 
@@ -56,7 +56,7 @@ Run ``build_prepare.py`` to configure the build::
       --depends PILLOW_DEPS
                             directory used to store cached dependencies (default:
                             'winbuild\depends')
-      --architecture {x64,ARM64}
+      --architecture {x86,x64,ARM64}
                             build architecture (default: same as host Python)
       --python PYTHON       Python install directory (default: use host Python)
       --executable EXECUTABLE

winbuild/build_prepare.py

@@ -3,6 +3,7 @@
 import platform
 import re
 import shutil
+import struct
 import subprocess
 import sys
 
@@ -97,6 +98,7 @@ def cmd_msbuild(
 SF_PROJECTS = "https://sourceforge.net/projects"
 
 architectures = {
+    "x86": {"vcvars_arch": "x86", "msbuild_arch": "Win32"},
     "x64": {"vcvars_arch": "x86_amd64", "msbuild_arch": "x64"},
     "ARM64": {"vcvars_arch": "x86_arm64", "msbuild_arch": "ARM64"},
 }
@@ -609,7 +611,11 @@ def build_pillow():
         choices=architectures,
         default=os.environ.get(
             "ARCHITECTURE",
-            "ARM64" if platform.machine() == "ARM64" else "x64",
+            (
+                "ARM64"
+                if platform.machine() == "ARM64"
+                else ("x86" if struct.calcsize("P") == 4 else "x64")
+            ),
         ),
         help="build architecture (default: same as host Python)",
     )