From 72862a7eb44b85706e2135531347f1f953743ef2 Mon Sep 17 00:00:00 2001
From: Michael Wu <mwu@mozilla.com>
Date: Mon, 29 Feb 2016 14:50:53 -0500
Subject: [PATCH] Add __rust_unsized_deallocate for C libraries to hook into.

__rust_deallocate requires a size to be passed in, especially when
jemalloc is used. Most C/C++ libraries don't use sized deallocation,
so this allows non-rust code to hook into Rust's allocator without
changing every free() call.
---
 src/doc/book/custom-allocators.md     | 5 +++++
 src/liballoc_jemalloc/lib.rs          | 9 +++++++++
 src/liballoc_system/lib.rs            | 5 +++++
 src/test/auxiliary/allocator-dummy.rs | 8 ++++++++
 4 files changed, 27 insertions(+)

diff --git a/src/doc/book/custom-allocators.md b/src/doc/book/custom-allocators.md
index d69ef6cf7e83a..1b6b925648843 100644
--- a/src/doc/book/custom-allocators.md
+++ b/src/doc/book/custom-allocators.md
@@ -110,6 +110,11 @@ pub extern fn __rust_allocate(size: usize, _align: usize) -> *mut u8 {
     unsafe { libc::malloc(size as libc::size_t) as *mut u8 }
 }
 
+#[no_mangle]
+pub extern fn __rust_unsized_deallocate(ptr: *mut u8, _align: usize) {
+    unsafe { libc::free(ptr as *mut libc::c_void) }
+}
+
 #[no_mangle]
 pub extern fn __rust_deallocate(ptr: *mut u8, _old_size: usize, _align: usize) {
     unsafe { libc::free(ptr as *mut libc::c_void) }
diff --git a/src/liballoc_jemalloc/lib.rs b/src/liballoc_jemalloc/lib.rs
index c96d303e6bb64..e32b7912ddae4 100644
--- a/src/liballoc_jemalloc/lib.rs
+++ b/src/liballoc_jemalloc/lib.rs
@@ -54,6 +54,9 @@ extern {
     #[cfg_attr(any(target_os = "macos", target_os = "android", target_os = "ios"),
                link_name = "je_xallocx")]
     fn xallocx(ptr: *mut c_void, size: size_t, extra: size_t, flags: c_int) -> size_t;
+    #[cfg_attr(any(target_os = "macos", target_os = "android", target_os = "ios"),
+               link_name = "je_dallocx")]
+    fn dallocx(ptr: *mut c_void, flags: c_int);
     #[cfg_attr(any(target_os = "macos", target_os = "android", target_os = "ios"),
                link_name = "je_sdallocx")]
     fn sdallocx(ptr: *mut c_void, size: size_t, flags: c_int);
@@ -114,6 +117,12 @@ pub extern "C" fn __rust_reallocate_inplace(ptr: *mut u8,
     unsafe { xallocx(ptr as *mut c_void, size as size_t, 0, flags) as usize }
 }
 
+#[no_mangle]
+pub extern "C" fn __rust_unsized_deallocate(ptr: *mut u8, align: usize) {
+    let flags = align_to_flags(align);
+    unsafe { dallocx(ptr as *mut c_void, flags) }
+}
+
 #[no_mangle]
 pub extern "C" fn __rust_deallocate(ptr: *mut u8, old_size: usize, align: usize) {
     let flags = align_to_flags(align);
diff --git a/src/liballoc_system/lib.rs b/src/liballoc_system/lib.rs
index 6a62e00d31169..0a52060fa1648 100644
--- a/src/liballoc_system/lib.rs
+++ b/src/liballoc_system/lib.rs
@@ -42,6 +42,11 @@ pub extern "C" fn __rust_allocate(size: usize, align: usize) -> *mut u8 {
     unsafe { imp::allocate(size, align) }
 }
 
+#[no_mangle]
+pub extern "C" fn __rust_unsized_deallocate(ptr: *mut u8, align: usize) {
+    unsafe { imp::deallocate(ptr, 0, align) }
+}
+
 #[no_mangle]
 pub extern "C" fn __rust_deallocate(ptr: *mut u8, old_size: usize, align: usize) {
     unsafe { imp::deallocate(ptr, old_size, align) }
diff --git a/src/test/auxiliary/allocator-dummy.rs b/src/test/auxiliary/allocator-dummy.rs
index a1d21db8f4d5d..d5eb87dd3ecac 100644
--- a/src/test/auxiliary/allocator-dummy.rs
+++ b/src/test/auxiliary/allocator-dummy.rs
@@ -27,6 +27,14 @@ pub extern fn __rust_allocate(size: usize, align: usize) -> *mut u8 {
     }
 }
 
+#[no_mangle]
+pub extern fn __rust_unsized_deallocate(ptr: *mut u8, align: usize) {
+    unsafe {
+        HITS += 1;
+        libc::free(ptr as *mut _)
+    }
+}
+
 #[no_mangle]
 pub extern fn __rust_deallocate(ptr: *mut u8, old_size: usize, align: usize) {
     unsafe {