saner parameter order for reallocation functions

Using reallocate(old_ptr, old_size, new_size, align) makes a lot more
sense than reallocate(old_ptr, new_size, align, old_size) and matches up
with the order used by existing platform APIs like mremap.

Closes #17837

[breaking-change]

src/liballoc/heap.rs

@@ -31,9 +31,8 @@ pub unsafe fn allocate(size: uint, align: uint) -> *mut u8 {
 /// create the allocation referenced by `ptr`. The `old_size` parameter may also
 /// be the value returned by `usable_size` for the requested size.
 #[inline]
-pub unsafe fn reallocate(ptr: *mut u8, size: uint, align: uint,
-                         old_size: uint) -> *mut u8 {
-    imp::reallocate(ptr, size, align, old_size)
+pub unsafe fn reallocate(ptr: *mut u8, old_size: uint, size: uint, align: uint) -> *mut u8 {
+    imp::reallocate(ptr, old_size, size, align)
 }
 
 /// Extends or shrinks the allocation referenced by `ptr` to `size` bytes of
@@ -50,9 +49,8 @@ pub unsafe fn reallocate(ptr: *mut u8, size: uint, align: uint,
 /// create the allocation referenced by `ptr`. The `old_size` parameter may be
 /// any value in range_inclusive(requested_size, usable_size).
 #[inline]
-pub unsafe fn reallocate_inplace(ptr: *mut u8, size: uint, align: uint,
-                                 old_size: uint) -> bool {
-    imp::reallocate_inplace(ptr, size, align, old_size)
+pub unsafe fn reallocate_inplace(ptr: *mut u8, old_size: uint, size: uint, align: uint) -> bool {
+    imp::reallocate_inplace(ptr, old_size, size, align)
 }
 
 /// Deallocates the memory referenced by `ptr`.
@@ -170,8 +168,7 @@ mod imp {
     }
 
     #[inline]
-    pub unsafe fn reallocate(ptr: *mut u8, size: uint, align: uint,
-                             _old_size: uint) -> *mut u8 {
+    pub unsafe fn reallocate(ptr: *mut u8, _old_size: uint, size: uint, align: uint) -> *mut u8 {
         let flags = align_to_flags(align);
         let ptr = je_rallocx(ptr as *mut c_void, size as size_t, flags) as *mut u8;
         if ptr.is_null() {
@@ -181,8 +178,8 @@ mod imp {
     }
 
     #[inline]
-    pub unsafe fn reallocate_inplace(ptr: *mut u8, size: uint, align: uint,
-                                     old_size: uint) -> bool {
+    pub unsafe fn reallocate_inplace(ptr: *mut u8, old_size: uint, size: uint,
+                                     align: uint) -> bool {
         let flags = align_to_flags(align);
         let new_size = je_xallocx(ptr as *mut c_void, size as size_t, 0, flags) as uint;
         // checking for failure to shrink is tricky
@@ -243,8 +240,7 @@ mod imp {
     }
 
     #[inline]
-    pub unsafe fn reallocate(ptr: *mut u8, size: uint, align: uint,
-                             old_size: uint) -> *mut u8 {
+    pub unsafe fn reallocate(ptr: *mut u8, old_size: uint, size: uint, align: uint) -> *mut u8 {
         if align <= MIN_ALIGN {
             libc_heap::realloc_raw(ptr, size)
         } else {
@@ -256,8 +252,8 @@ mod imp {
     }
 
     #[inline]
-    pub unsafe fn reallocate_inplace(_ptr: *mut u8, size: uint, _align: uint,
-                                     old_size: uint) -> bool {
+    pub unsafe fn reallocate_inplace(_ptr: *mut u8, old_size: uint, size: uint,
+                                     _align: uint) -> bool {
         size == old_size
     }
 
@@ -303,8 +299,7 @@ mod imp {
     }
 
     #[inline]
-    pub unsafe fn reallocate(ptr: *mut u8, size: uint, align: uint,
-                             _old_size: uint) -> *mut u8 {
+    pub unsafe fn reallocate(ptr: *mut u8, _old_size: uint, size: uint, align: uint) -> *mut u8 {
         if align <= MIN_ALIGN {
             libc_heap::realloc_raw(ptr, size)
         } else {
@@ -318,8 +313,8 @@ mod imp {
     }
 
     #[inline]
-    pub unsafe fn reallocate_inplace(_ptr: *mut u8, size: uint, _align: uint,
-                                     old_size: uint) -> bool {
+    pub unsafe fn reallocate_inplace(_ptr: *mut u8, old_size: uint, size: uint,
+                                     _align: uint) -> bool {
         size == old_size
     }
 
@@ -351,7 +346,7 @@ mod test {
         unsafe {
             let size = 4000;
             let ptr = heap::allocate(size, 8);
-            let ret = heap::reallocate_inplace(ptr, size, 8, size);
+            let ret = heap::reallocate_inplace(ptr, size, size, 8);
             heap::deallocate(ptr, size, 8);
             assert!(ret);
         }

src/libcollections/vec.rs

@@ -622,12 +622,11 @@ impl<T: Clone> CloneableVector<T> for Vec<T> {
 
 // FIXME: #13996: need a way to mark the return value as `noalias`
 #[inline(never)]
-unsafe fn alloc_or_realloc<T>(ptr: *mut T, size: uint, old_size: uint) -> *mut T {
+unsafe fn alloc_or_realloc<T>(ptr: *mut T, old_size: uint, size: uint) -> *mut T {
     if old_size == 0 {
         allocate(size, mem::min_align_of::<T>()) as *mut T
     } else {
-        reallocate(ptr as *mut u8, size,
-                   mem::min_align_of::<T>(), old_size) as *mut T
+        reallocate(ptr as *mut u8, old_size, size, mem::min_align_of::<T>()) as *mut T
     }
 }
 
@@ -720,8 +719,7 @@ impl<T> Vec<T> {
             let size = capacity.checked_mul(&mem::size_of::<T>())
                                .expect("capacity overflow");
             unsafe {
-                self.ptr = alloc_or_realloc(self.ptr, size,
-                                            self.cap * mem::size_of::<T>());
+                self.ptr = alloc_or_realloc(self.ptr, self.cap * mem::size_of::<T>(), size);
             }
             self.cap = capacity;
         }
@@ -751,9 +749,9 @@ impl<T> Vec<T> {
                 // Overflow check is unnecessary as the vector is already at
                 // least this large.
                 self.ptr = reallocate(self.ptr as *mut u8,
+                                      self.cap * mem::size_of::<T>(),
                                       self.len * mem::size_of::<T>(),
-                                      mem::min_align_of::<T>(),
-                                      self.cap * mem::size_of::<T>()) as *mut T;
+                                      mem::min_align_of::<T>()) as *mut T;
             }
             self.cap = self.len;
         }
@@ -1736,8 +1734,7 @@ impl<T> MutableSeq<T> for Vec<T> {
             let size = max(old_size, 2 * mem::size_of::<T>()) * 2;
             if old_size > size { fail!("capacity overflow") }
             unsafe {
-                self.ptr = alloc_or_realloc(self.ptr, size,
-                                            self.cap * mem::size_of::<T>());
+                self.ptr = alloc_or_realloc(self.ptr, self.cap * mem::size_of::<T>(), size);
             }
             self.cap = max(self.cap, 2) * 2;
         }

src/test/run-pass/realloc-16687.rs

@@ -63,19 +63,18 @@ unsafe fn test_triangle() -> bool {
 
         heap::deallocate(ptr, size, align);
     }
-    unsafe fn reallocate(ptr: *mut u8, size: uint, align: uint,
-                             old_size: uint) -> *mut u8 {
+    unsafe fn reallocate(ptr: *mut u8, old_size: uint, size: uint, align: uint) -> *mut u8 {
         if PRINT {
-            println!("reallocate(ptr=0x{:010x} size={:u} align={:u} old_size={:u})",
-                     ptr as uint, size, align, old_size);
+            println!("reallocate(ptr=0x{:010x} old_size={:u} size={:u} align={:u})",
+                     ptr as uint, old_size, size, align);
         }
 
-        let ret = heap::reallocate(ptr, size, align, old_size);
+        let ret = heap::reallocate(ptr, old_size, size, align);
 
         if PRINT {
-            println!("reallocate(ptr=0x{:010x} size={:u} align={:u} old_size={:u}) \
+            println!("reallocate(ptr=0x{:010x} old_size={:u} size={:u} align={:u}) \
                       ret: 0x{:010x}",
-                     ptr as uint, size, align, old_size, ret as uint);
+                     ptr as uint, old_size, size, align, ret as uint);
         }
         ret
     }
@@ -125,10 +124,10 @@ unsafe fn test_triangle() -> bool {
             let (p0, p1, old_size) = (ascend[2*i], ascend[2*i+1], idx_to_size(i));
             assert!(old_size < new_size);
 
-            ascend[2*i] = reallocate(p0, new_size, ALIGN, old_size);
+            ascend[2*i] = reallocate(p0, old_size, new_size, ALIGN);
             sanity_check(ascend.as_slice());
 
-            ascend[2*i+1] = reallocate(p1, new_size, ALIGN, old_size);
+            ascend[2*i+1] = reallocate(p1, old_size, new_size, ALIGN);
             sanity_check(ascend.as_slice());
         }
     }
@@ -140,10 +139,10 @@ unsafe fn test_triangle() -> bool {
             let (p0, p1, new_size) = (ascend[2*i], ascend[2*i+1], idx_to_size(i));
             assert!(new_size < old_size);
 
-            ascend[2*i] = reallocate(p0, new_size, ALIGN, old_size);
+            ascend[2*i] = reallocate(p0, old_size, new_size, ALIGN);
             sanity_check(ascend.as_slice());
 
-            ascend[2*i+1] = reallocate(p1, new_size, ALIGN, old_size);
+            ascend[2*i+1] = reallocate(p1, old_size, new_size, ALIGN);
             sanity_check(ascend.as_slice());
         }
     }
@@ -155,10 +154,10 @@ unsafe fn test_triangle() -> bool {
             let (p0, p1, old_size) = (ascend[2*i], ascend[2*i+1], idx_to_size(i));
             assert!(old_size < new_size);
 
-            ascend[2*i+1] = reallocate(p1, new_size, ALIGN, old_size);
+            ascend[2*i+1] = reallocate(p1, old_size, new_size, ALIGN);
             sanity_check(ascend.as_slice());
 
-            ascend[2*i] = reallocate(p0, new_size, ALIGN, old_size);
+            ascend[2*i] = reallocate(p0, old_size, new_size, ALIGN);
             sanity_check(ascend.as_slice());
         }
     }
@@ -170,10 +169,10 @@ unsafe fn test_triangle() -> bool {
             let (p0, p1, new_size) = (ascend[2*i], ascend[2*i+1], idx_to_size(i));
             assert!(new_size < old_size);
 
-            ascend[2*i+1] = reallocate(p1, new_size, ALIGN, old_size);
+            ascend[2*i+1] = reallocate(p1, old_size, new_size, ALIGN);
             sanity_check(ascend.as_slice());
 
-            ascend[2*i] = reallocate(p0, new_size, ALIGN, old_size);
+            ascend[2*i] = reallocate(p0, old_size, new_size, ALIGN);
             sanity_check(ascend.as_slice());
         }
     }