1 files changed, 130 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_cranelift/example/alloc_system.rs b/compiler/rustc_codegen_cranelift/example/alloc_system.rs
new file mode 100644
index 000000000..cf95c89bc
--- /dev/null
+++ b/compiler/rustc_codegen_cranelift/example/alloc_system.rs
@@ -0,0 +1,130 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+#![no_std]
+
+pub struct System;
+
+#[cfg(any(windows, unix, target_os = "redox"))]
+mod realloc_fallback {
+    use core::alloc::{GlobalAlloc, Layout};
+    use core::cmp;
+    use core::ptr;
+    impl super::System {
+        pub(crate) unsafe fn realloc_fallback(
+            &self,
+            ptr: *mut u8,
+            old_layout: Layout,
+            new_size: usize,
+        ) -> *mut u8 {
+            // Docs for GlobalAlloc::realloc require this to be valid:
+            let new_layout = Layout::from_size_align_unchecked(new_size, old_layout.align());
+            let new_ptr = GlobalAlloc::alloc(self, new_layout);
+            if !new_ptr.is_null() {
+                let size = cmp::min(old_layout.size(), new_size);
+                ptr::copy_nonoverlapping(ptr, new_ptr, size);
+                GlobalAlloc::dealloc(self, ptr, old_layout);
+            }
+            new_ptr
+        }
+    }
+}
+#[cfg(any(unix, target_os = "redox"))]
+mod platform {
+    use core::alloc::{GlobalAlloc, Layout};
+    use core::ffi::c_void;
+    use core::ptr;
+    use System;
+    extern "C" {
+        fn posix_memalign(memptr: *mut *mut c_void, align: usize, size: usize) -> i32;
+        fn free(p: *mut c_void);
+    }
+    unsafe impl GlobalAlloc for System {
+        #[inline]
+        unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+            aligned_malloc(&layout)
+        }
+        #[inline]
+        unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
+            let ptr = self.alloc(layout.clone());
+            if !ptr.is_null() {
+                ptr::write_bytes(ptr, 0, layout.size());
+            }
+            ptr
+        }
+        #[inline]
+        unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
+            free(ptr as *mut c_void)
+        }
+        #[inline]
+        unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
+            self.realloc_fallback(ptr, layout, new_size)
+        }
+    }
+    unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 {
+        let mut out = ptr::null_mut();
+        let ret = posix_memalign(&mut out, layout.align(), layout.size());
+        if ret != 0 { ptr::null_mut() } else { out as *mut u8 }
+    }
+}
+#[cfg(windows)]
+#[allow(nonstandard_style)]
+mod platform {
+    use core::alloc::{GlobalAlloc, Layout};
+    use System;
+    type LPVOID = *mut u8;
+    type HANDLE = LPVOID;
+    type SIZE_T = usize;
+    type DWORD = u32;
+    type BOOL = i32;
+    extern "system" {
+        fn GetProcessHeap() -> HANDLE;
+        fn HeapAlloc(hHeap: HANDLE, dwFlags: DWORD, dwBytes: SIZE_T) -> LPVOID;
+        fn HeapReAlloc(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID, dwBytes: SIZE_T) -> LPVOID;
+        fn HeapFree(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID) -> BOOL;
+        fn GetLastError() -> DWORD;
+    }
+    #[repr(C)]
+    struct Header(*mut u8);
+    const HEAP_ZERO_MEMORY: DWORD = 0x00000008;
+    unsafe fn get_header<'a>(ptr: *mut u8) -> &'a mut Header {
+        &mut *(ptr as *mut Header).offset(-1)
+    }
+    unsafe fn align_ptr(ptr: *mut u8, align: usize) -> *mut u8 {
+        let aligned = ptr.add(align - (ptr as usize & (align - 1)));
+        *get_header(aligned) = Header(ptr);
+        aligned
+    }
+    #[inline]
+    unsafe fn allocate_with_flags(layout: Layout, flags: DWORD) -> *mut u8 {
+        let size = layout.size() + layout.align();
+        let ptr = HeapAlloc(GetProcessHeap(), flags, size);
+        (if ptr.is_null() { ptr } else { align_ptr(ptr, layout.align()) }) as *mut u8
+    }
+    unsafe impl GlobalAlloc for System {
+        #[inline]
+        unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+            allocate_with_flags(layout, 0)
+        }
+        #[inline]
+        unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
+            allocate_with_flags(layout, HEAP_ZERO_MEMORY)
+        }
+        #[inline]
+        unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
+            let header = get_header(ptr);
+            let err = HeapFree(GetProcessHeap(), 0, header.0 as LPVOID);
+            debug_assert!(err != 0, "Failed to free heap memory: {}", GetLastError());
+        }
+        #[inline]
+        unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
+            self.realloc_fallback(ptr, layout, new_size)
+        }
+    }
+}