Use addr_of_mut in pyo3-ffi

build.rs

@@ -1,7 +1,7 @@
-use std::{env, process::Command};
+use std::env;
 
 use pyo3_build_config::pyo3_build_script_impl::{cargo_env_var, errors::Result};
-use pyo3_build_config::{bail, InterpreterConfig};
+use pyo3_build_config::{bail, print_feature_cfgs, InterpreterConfig};
 
 fn ensure_auto_initialize_ok(interpreter_config: &InterpreterConfig) -> Result<()> {
     if cargo_env_var("CARGO_FEATURE_AUTO_INITIALIZE").is_some() {
@@ -32,17 +32,6 @@ fn ensure_auto_initialize_ok(interpreter_config: &InterpreterConfig) -> Result<(
     Ok(())
 }
 
-fn rustc_minor_version() -> Option<u32> {
-    let rustc = env::var_os("RUSTC")?;
-    let output = Command::new(rustc).arg("--version").output().ok()?;
-    let version = core::str::from_utf8(&output.stdout).ok()?;
-    let mut pieces = version.split('.');
-    if pieces.next() != Some("rustc 1") {
-        return None;
-    }
-    pieces.next()?.parse().ok()
-}
-
 /// Prepares the PyO3 crate for compilation.
 ///
 /// This loads the config from pyo3-build-config and then makes some additional checks to improve UX
@@ -55,18 +44,10 @@ fn configure_pyo3() -> Result<()> {
 
     interpreter_config.emit_pyo3_cfgs();
 
-    let rustc_minor_version = rustc_minor_version().unwrap_or(0);
     ensure_auto_initialize_ok(interpreter_config)?;
 
-    // Enable use of const generics on Rust 1.51 and greater
-    if rustc_minor_version >= 51 {
-        println!("cargo:rustc-cfg=min_const_generics");
-    }
-
-    // Enable use of std::ptr::addr_of! on Rust 1.51 and greater
-    if rustc_minor_version >= 51 {
-        println!("cargo:rustc-cfg=addr_of");
-    }
+    // Emit cfgs like `addr_of` and `min_const_generics`
+    print_feature_cfgs();
 
     Ok(())
 }

pyo3-build-config/src/lib.rs

@@ -10,6 +10,7 @@ mod impl_;
 
 #[cfg(feature = "resolve-config")]
 use std::io::Cursor;
+use std::{env, process::Command};
 
 #[cfg(feature = "resolve-config")]
 use once_cell::sync::OnceCell;
@@ -115,6 +116,36 @@ fn abi3_config() -> InterpreterConfig {
     interpreter_config
 }
 
+/// Use certain features if we detect the compiler being used supports them.
+///
+/// Features may be removed or added as MSRV gets bumped or new features become available,
+/// so this function is unstable.
+#[doc(hidden)]
+pub fn print_feature_cfgs() {
+    fn rustc_minor_version() -> Option<u32> {
+        let rustc = env::var_os("RUSTC")?;
+        let output = Command::new(rustc).arg("--version").output().ok()?;
+        let version = core::str::from_utf8(&output.stdout).ok()?;
+        let mut pieces = version.split('.');
+        if pieces.next() != Some("rustc 1") {
+            return None;
+        }
+        pieces.next()?.parse().ok()
+    }
+
+    let rustc_minor_version = rustc_minor_version().unwrap_or(0);
+
+    // Enable use of const generics on Rust 1.51 and greater
+    if rustc_minor_version >= 51 {
+        println!("cargo:rustc-cfg=min_const_generics");
+    }
+
+    // Enable use of std::ptr::addr_of! on Rust 1.51 and greater
+    if rustc_minor_version >= 51 {
+        println!("cargo:rustc-cfg=addr_of");
+    }
+}
+
 /// Private exports used in PyO3's build.rs
 ///
 /// Please don't use these - they could change at any time.

pyo3-ffi/build.rs

@@ -1,5 +1,5 @@
 use pyo3_build_config::{
-    bail, ensure,
+    bail, ensure, print_feature_cfgs,
     pyo3_build_script_impl::{
         cargo_env_var, env_var, errors::Result, resolve_interpreter_config, InterpreterConfig,
         PythonVersion,
@@ -100,6 +100,9 @@ fn configure_pyo3() -> Result<()> {
         println!("{}", line);
     }
 
+    // Emit cfgs like `addr_of` and `min_const_generics`
+    print_feature_cfgs();
+
     Ok(())
 }
 

pyo3-ffi/src/boolobject.rs

@@ -10,7 +10,7 @@ extern "C" {
 
 #[inline]
 pub unsafe fn PyBool_Check(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyBool_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyBool_Type)) as c_int
 }
 
 #[cfg_attr(windows, link(name = "pythonXY"))]
@@ -23,12 +23,12 @@ extern "C" {
 
 #[inline]
 pub unsafe fn Py_False() -> *mut PyObject {
-    &mut _Py_FalseStruct as *mut PyLongObject as *mut PyObject
+    addr_of_mut_shim!(_Py_FalseStruct) as *mut PyLongObject as *mut PyObject
 }
 
 #[inline]
 pub unsafe fn Py_True() -> *mut PyObject {
-    &mut _Py_TrueStruct as *mut PyLongObject as *mut PyObject
+    addr_of_mut_shim!(_Py_TrueStruct) as *mut PyLongObject as *mut PyObject
 }
 
 #[inline]

pyo3-ffi/src/bytearrayobject.rs

@@ -12,12 +12,12 @@ extern "C" {
 
 #[inline]
 pub unsafe fn PyByteArray_Check(op: *mut PyObject) -> c_int {
-    PyObject_TypeCheck(op, &mut PyByteArray_Type)
+    PyObject_TypeCheck(op, addr_of_mut_shim!(PyByteArray_Type))
 }
 
 #[inline]
 pub unsafe fn PyByteArray_CheckExact(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyByteArray_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyByteArray_Type)) as c_int
 }
 
 extern "C" {

pyo3-ffi/src/bytesobject.rs

@@ -16,7 +16,7 @@ pub unsafe fn PyBytes_Check(op: *mut PyObject) -> c_int {
 
 #[inline]
 pub unsafe fn PyBytes_CheckExact(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyBytes_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyBytes_Type)) as c_int
 }
 
 extern "C" {

pyo3-ffi/src/complexobject.rs

@@ -40,12 +40,12 @@ extern "C" {
 
 #[inline]
 pub unsafe fn PyComplex_Check(op: *mut PyObject) -> c_int {
-    PyObject_TypeCheck(op, &mut PyComplex_Type)
+    PyObject_TypeCheck(op, addr_of_mut_shim!(PyComplex_Type))
 }
 
 #[inline]
 pub unsafe fn PyComplex_CheckExact(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyComplex_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyComplex_Type)) as c_int
 }
 
 extern "C" {

pyo3-ffi/src/context.rs

@@ -12,17 +12,17 @@ extern "C" {
 
 #[inline]
 pub unsafe fn PyContext_CheckExact(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyContext_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyContext_Type)) as c_int
 }
 
 #[inline]
 pub unsafe fn PyContextVar_CheckExact(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyContextVar_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyContextVar_Type)) as c_int
 }
 
 #[inline]
 pub unsafe fn PyContextToken_CheckExact(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyContextToken_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyContextToken_Type)) as c_int
 }
 
 extern "C" {

pyo3-ffi/src/cpython/code.rs

@@ -84,7 +84,7 @@ extern "C" {
 #[inline]
 #[cfg(not(PyPy))]
 pub unsafe fn PyCode_Check(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyCode_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyCode_Type)) as c_int
 }
 
 #[inline]

pyo3-ffi/src/cpython/frameobject.rs

@@ -60,7 +60,7 @@ extern "C" {
 
 #[inline]
 pub unsafe fn PyFrame_Check(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyFrame_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyFrame_Type)) as c_int
 }
 
 extern "C" {

pyo3-ffi/src/dictobject.rs

@@ -15,7 +15,7 @@ pub unsafe fn PyDict_Check(op: *mut PyObject) -> c_int {
 
 #[inline]
 pub unsafe fn PyDict_CheckExact(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyDict_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyDict_Type)) as c_int
 }
 
 extern "C" {
@@ -76,17 +76,17 @@ extern "C" {
 
 #[inline]
 pub unsafe fn PyDictKeys_Check(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyDictKeys_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyDictKeys_Type)) as c_int
 }
 
 #[inline]
 pub unsafe fn PyDictValues_Check(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyDictValues_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyDictValues_Type)) as c_int
 }
 
 #[inline]
 pub unsafe fn PyDictItems_Check(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyDictItems_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyDictItems_Type)) as c_int
 }
 
 #[inline]

pyo3-ffi/src/floatobject.rs

@@ -20,12 +20,12 @@ extern "C" {
 
 #[inline]
 pub unsafe fn PyFloat_Check(op: *mut PyObject) -> c_int {
-    PyObject_TypeCheck(op, &mut PyFloat_Type)
+    PyObject_TypeCheck(op, addr_of_mut_shim!(PyFloat_Type))
 }
 
 #[inline]
 pub unsafe fn PyFloat_CheckExact(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyFloat_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyFloat_Type)) as c_int
 }
 
 // skipped Py_RETURN_NAN

pyo3-ffi/src/funcobject.rs

@@ -12,7 +12,7 @@ extern "C" {
 
 #[inline]
 pub unsafe fn PyFunction_Check(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyFunction_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyFunction_Type)) as c_int
 }
 
 extern "C" {

pyo3-ffi/src/genobject.rs

@@ -25,12 +25,12 @@ extern "C" {
 
 #[inline]
 pub unsafe fn PyGen_Check(op: *mut PyObject) -> c_int {
-    PyObject_TypeCheck(op, &mut PyGen_Type)
+    PyObject_TypeCheck(op, addr_of_mut_shim!(PyGen_Type))
 }
 
 #[inline]
 pub unsafe fn PyGen_CheckExact(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyGen_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyGen_Type)) as c_int
 }
 
 extern "C" {
@@ -55,7 +55,7 @@ extern "C" {
 
 #[inline]
 pub unsafe fn PyCoro_CheckExact(op: *mut PyObject) -> c_int {
-    PyObject_TypeCheck(op, &mut PyCoro_Type)
+    PyObject_TypeCheck(op, addr_of_mut_shim!(PyCoro_Type))
 }
 
 // skipped _PyCoro_GetAwaitableIter
@@ -75,7 +75,7 @@ extern "C" {
 
 #[inline]
 pub unsafe fn PyAsyncGen_CheckExact(op: *mut PyObject) -> c_int {
-    PyObject_TypeCheck(op, &mut PyAsyncGen_Type)
+    PyObject_TypeCheck(op, addr_of_mut_shim!(PyAsyncGen_Type))
 }
 
 // skipped _PyAsyncGenValueWrapperNew

pyo3-ffi/src/iterobject.rs

@@ -9,7 +9,7 @@ extern "C" {
 
 #[inline]
 pub unsafe fn PySeqIter_Check(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PySeqIter_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PySeqIter_Type)) as c_int
 }
 
 extern "C" {
@@ -19,7 +19,7 @@ extern "C" {
 
 #[inline]
 pub unsafe fn PyCallIter_Check(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyCallIter_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyCallIter_Type)) as c_int
 }
 
 extern "C" {

pyo3-ffi/src/lib.rs

@@ -265,6 +265,19 @@ macro_rules! opaque_struct {
     };
 }
 
+macro_rules! addr_of_mut_shim {
+    ($place:expr) => {{
+        #[cfg(addr_of)]
+        {
+            ::std::ptr::addr_of_mut!($place)
+        }
+        #[cfg(not(addr_of))]
+        {
+            &mut $place as *mut _
+        }
+    }};
+}
+
 pub use self::abstract_::*;
 pub use self::bltinmodule::*;
 pub use self::boolobject::*;

pyo3-ffi/src/listobject.rs

@@ -17,7 +17,7 @@ pub unsafe fn PyList_Check(op: *mut PyObject) -> c_int {
 
 #[inline]
 pub unsafe fn PyList_CheckExact(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyList_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyList_Type)) as c_int
 }
 
 extern "C" {

pyo3-ffi/src/longobject.rs

@@ -20,7 +20,7 @@ pub unsafe fn PyLong_Check(op: *mut PyObject) -> c_int {
 
 #[inline]
 pub unsafe fn PyLong_CheckExact(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyLong_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyLong_Type)) as c_int
 }
 
 extern "C" {

pyo3-ffi/src/memoryobject.rs

@@ -12,7 +12,7 @@ extern "C" {
 
 #[inline]
 pub unsafe fn PyMemoryView_Check(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyMemoryView_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyMemoryView_Type)) as c_int
 }
 
 // skipped non-limited PyMemoryView_GET_BUFFER

pyo3-ffi/src/methodobject.rs

@@ -13,19 +13,19 @@ extern "C" {
 #[cfg(Py_3_9)]
 #[inline]
 pub unsafe fn PyCFunction_CheckExact(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyCFunction_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyCFunction_Type)) as c_int
 }
 
 #[cfg(Py_3_9)]
 #[inline]
 pub unsafe fn PyCFunction_Check(op: *mut PyObject) -> c_int {
-    PyObject_TypeCheck(op, &mut PyCFunction_Type)
+    PyObject_TypeCheck(op, addr_of_mut_shim!(PyCFunction_Type))
 }
 
 #[cfg(not(Py_3_9))]
 #[inline]
 pub unsafe fn PyCFunction_Check(op: *mut PyObject) -> c_int {
-    (Py_TYPE(op) == &mut PyCFunction_Type) as c_int
+    (Py_TYPE(op) == addr_of_mut_shim!(PyCFunction_Type)) as c_int
 }
 
 pub type PyCFunction =