diff --git a/components/fallible/lib.rs b/components/fallible/lib.rs
index 4a48190a1eb..c220699a786 100644
--- a/components/fallible/lib.rs
+++ b/components/fallible/lib.rs
@@ -6,16 +6,12 @@ extern crate hashglobe;
 extern crate smallvec;
 
 use hashglobe::FailedAllocationError;
+#[cfg(feature = "known_system_malloc")]
+use hashglobe::alloc;
 use smallvec::Array;
 use smallvec::SmallVec;
 use std::vec::Vec;
 
-#[cfg(feature = "known_system_malloc")]
-extern "C" {
-    fn realloc(ptr: *mut u8, bytes: usize) -> *mut u8;
-    fn malloc(bytes: usize) -> *mut u8;
-}
-
 pub trait FallibleVec<T> {
     /// Append |val| to the end of |vec|.  Returns Ok(()) on success,
     /// Err(reason) if it fails, with |reason| describing the failure.
@@ -67,9 +63,9 @@ fn try_double_vec<T>(vec: &mut Vec<T>) -> Result<(), FailedAllocationError> {
 
     let new_ptr = unsafe {
         if old_cap == 0 {
-            malloc(new_size_bytes)
+            alloc::alloc(new_size_bytes, 0)
         } else {
-            realloc(old_ptr as *mut u8, new_size_bytes)
+            alloc::realloc(old_ptr as *mut u8, new_size_bytes)
         }
     };
 
@@ -146,12 +142,12 @@ where
         // There's an old block to free, and, presumably, old contents to
         // copy.  realloc takes care of both aspects.
         unsafe {
-            new_ptr = realloc(old_ptr as *mut u8, new_size_bytes);
+            new_ptr = alloc::realloc(old_ptr as *mut u8, new_size_bytes);
         }
     } else {
         // There's no old block to free.  There may be old contents to copy.
         unsafe {
-            new_ptr = malloc(new_size_bytes);
+            new_ptr = alloc::alloc(new_size_bytes, 0);
             if !new_ptr.is_null() && old_size_bytes > 0 {
                 copy_nonoverlapping(old_ptr as *const u8,
                                     new_ptr as *mut u8, old_size_bytes);
diff --git a/components/hashglobe/src/alloc.rs b/components/hashglobe/src/alloc.rs
index c5e213b2931..f7d50501467 100644
--- a/components/hashglobe/src/alloc.rs
+++ b/components/hashglobe/src/alloc.rs
@@ -22,7 +22,7 @@ const MIN_ALIGN: usize = 8;
               target_arch = "sparc64")))]
 const MIN_ALIGN: usize = 16;
 
-pub use self::platform::{alloc, dealloc};
+pub use self::platform::{alloc, dealloc, realloc};
 
 #[cfg(any(unix, target_os = "redox"))]
 mod platform {
@@ -47,6 +47,11 @@ mod platform {
         libc::free(ptr as *mut libc::c_void)
     }
 
+    #[inline]
+    pub unsafe fn realloc(ptr: *mut u8, new_size: usize) -> *mut u8 {
+        libc::realloc(ptr as *mut libc::c_void, new_size) as *mut u8
+    }
+
     #[cfg(any(target_os = "android", target_os = "redox"))]
     #[inline]
     unsafe fn aligned_malloc(size: usize, align: usize) -> *mut u8 {
@@ -98,6 +103,7 @@ mod platform {
     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;
     }
@@ -149,4 +155,12 @@ mod platform {
                           GetLastError());
         }
     }
+
+    #[inline]
+    pub unsafe fn realloc(ptr: *mut u8, new_size: usize) -> *mut u8 {
+        HeapReAlloc(GetProcessHeap(),
+                    0,
+                    ptr as LPVOID,
+                    new_size) as *mut u8
+    }
 }
diff --git a/components/hashglobe/src/lib.rs b/components/hashglobe/src/lib.rs
index cdb98ad2003..f9d5109a51d 100644
--- a/components/hashglobe/src/lib.rs
+++ b/components/hashglobe/src/lib.rs
@@ -10,7 +10,7 @@
 
 extern crate heapsize;
 
-mod alloc;
+pub mod alloc;
 pub mod hash_map;
 pub mod hash_set;
 pub mod protected;