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| author | Andrew Martin <andrew.thaddeus@gmail.com> | 2019-08-19 08:18:19 -0400 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2019-10-26 05:19:38 -0400 |
| commit | 8916e64e5437c99b82d5610286430328af1d86bc (patch) | |
| tree | 3c9f00fbed65cb725b57acb0ee7b83d776475a89 /compiler/prelude/primops.txt.pp | |
| parent | acedfc8b8706a92127c96f487e3e3b1636451704 (diff) | |
| download | haskell-8916e64e5437c99b82d5610286430328af1d86bc.tar.gz | |
Implement shrinkSmallMutableArray# and resizeSmallMutableArray#.
This is a part of GHC Proposal #25: "Offer more array resizing primitives".
Resources related to the proposal:
- Discussion: https://github.com/ghc-proposals/ghc-proposals/pull/121
- Proposal: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0025-resize-boxed.rst
Only shrinkSmallMutableArray# is implemented as a primop since a
library-space implementation of resizeSmallMutableArray# (in GHC.Exts)
is no less efficient than a primop would be. This may be replaced by
a primop in the future if someone devises a strategy for growing
arrays in-place. The library-space implementation always copies the
array when growing it.
This commit also tweaks the documentation of the deprecated
sizeofMutableByteArray#, removing the mention of concurrency. That
primop is unsound even in single-threaded applications. Additionally,
the non-negativity assertion on the existing shrinkMutableByteArray#
primop has been removed since this predicate is trivially always true.
Diffstat (limited to 'compiler/prelude/primops.txt.pp')
| -rw-r--r-- | compiler/prelude/primops.txt.pp | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/compiler/prelude/primops.txt.pp b/compiler/prelude/primops.txt.pp index 47a78e2c8d..f47880b58d 100644 --- a/compiler/prelude/primops.txt.pp +++ b/compiler/prelude/primops.txt.pp @@ -1244,6 +1244,14 @@ primop NewSmallArrayOp "newSmallArray#" GenPrimOp primop SameSmallMutableArrayOp "sameSmallMutableArray#" GenPrimOp SmallMutableArray# s a -> SmallMutableArray# s a -> Int# +primop ShrinkSmallMutableArrayOp_Char "shrinkSmallMutableArray#" GenPrimOp + SmallMutableArray# s a -> Int# -> State# s -> State# s + {Shrink mutable array to new specified size, in + the specified state thread. The new size argument must be less than or + equal to the current size as reported by {\tt sizeofSmallMutableArray\#}.} + with out_of_line = True + has_side_effects = True + primop ReadSmallArrayOp "readSmallArray#" GenPrimOp SmallMutableArray# s a -> Int# -> State# s -> (# State# s, a #) {Read from specified index of mutable array. Result is not yet evaluated.} @@ -1264,6 +1272,13 @@ primop SizeofSmallArrayOp "sizeofSmallArray#" GenPrimOp primop SizeofSmallMutableArrayOp "sizeofSmallMutableArray#" GenPrimOp SmallMutableArray# s a -> Int# + {Return the number of elements in the array. Note that this is deprecated + as it is unsafe in the presence of resize operations on the + same byte array.} + with deprecated_msg = { Use 'getSizeofSmallMutableArray#' instead } + +primop GetSizeofSmallMutableArrayOp "getSizeofSmallMutableArray#" GenPrimOp + SmallMutableArray# s a -> State# s -> (# State# s, Int# #) {Return the number of elements in the array.} primop IndexSmallArrayOp "indexSmallArray#" GenPrimOp @@ -1463,7 +1478,7 @@ primop SizeofByteArrayOp "sizeofByteArray#" GenPrimOp primop SizeofMutableByteArrayOp "sizeofMutableByteArray#" GenPrimOp MutableByteArray# s -> Int# {Return the size of the array in bytes. Note that this is deprecated as it is - unsafe in the presence of concurrent resize operations on the same byte + unsafe in the presence of resize operations on the same byte array.} with deprecated_msg = { Use 'getSizeofMutableByteArray#' instead } |