std: init HEAP only once

Author: Berrysoft

library/std/src/sys/pal/windows/alloc.rs

@@ -89,30 +89,12 @@ extern "system" {
 // Either a non-null handle returned by `GetProcessHeap`, or null when not yet initialized or `GetProcessHeap` failed.
 static HEAP: AtomicPtr<c_void> = AtomicPtr::new(ptr::null_mut());
 
-// Get a handle to the default heap of the current process, or null if the operation fails.
-// If this operation is successful, `HEAP` will be successfully initialized and contain
-// a non-null handle returned by `GetProcessHeap`.
-#[inline]
-fn init_or_get_process_heap() -> c::HANDLE {
-    let heap = HEAP.load(Ordering::Relaxed);
-    if heap.is_null() {
-        // `HEAP` has not yet been successfully initialized
-        let heap = unsafe { GetProcessHeap() };
-        if !heap.is_null() {
-            // SAFETY: No locking is needed because within the same process,
-            // successful calls to `GetProcessHeap` will always return the same value, even on different threads.
-            HEAP.store(heap, Ordering::Release);
-
-            // SAFETY: `HEAP` contains a non-null handle returned by `GetProcessHeap`
-            heap
-        } else {
-            // Could not get the current process heap.
-            ptr::null_mut()
-        }
-    } else {
-        // SAFETY: `HEAP` contains a non-null handle returned by `GetProcessHeap`
-        heap
-    }
+// Initialize `HEAP` when the app starts.
+pub fn init() {
+    let heap = unsafe { GetProcessHeap() };
+    // SAFETY: No locking is needed because within the same process,
+    // successful calls to `GetProcessHeap` will always return the same value, even on different threads.
+    HEAP.store(heap, Ordering::Release);
 }
 
 // Get a non-null handle to the default heap of the current process.
@@ -133,7 +115,8 @@ struct Header(*mut u8);
 // initialized.
 #[inline]
 unsafe fn allocate(layout: Layout, zeroed: bool) -> *mut u8 {
-    let heap = init_or_get_process_heap();
+    // SAFETY: Check the pointer here.
+    let heap = unsafe { get_process_heap() };
     if heap.is_null() {
         // Allocation has failed, could not get the current process heap.
         return ptr::null_mut();

library/std/src/sys/pal/windows/mod.rs

@@ -58,6 +58,7 @@ impl<T> IoResult<T> for Result<T, api::WinError> {
 // SAFETY: must be called only once during runtime initialization.
 // NOTE: this is not guaranteed to run, for example when Rust code is called externally.
 pub unsafe fn init(_argc: isize, _argv: *const *const u8, _sigpipe: u8) {
+    alloc::init();
     stack_overflow::init();
 
     // Normally, `thread::spawn` will call `Thread::set_name` but since this thread already