1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
|
{-# OPTIONS_GHC -fno-warn-name-shadowing #-}
{-# LANGUAGE CPP, MagicHash, UnboxedTuples #-}
-------------------------------------------------------------------------------
--
-- (c) The University of Glasgow 2007
--
-- | Break Arrays
--
-- An array of bytes, indexed by a breakpoint number (breakpointId in Tickish)
-- There is one of these arrays per module.
--
-- Each byte is
-- 1 if the corresponding breakpoint is enabled
-- 0 otherwise
--
-------------------------------------------------------------------------------
module GHCi.BreakArray
(
BreakArray
(BA) -- constructor is exported only for GHC.CoreToByteCode
, newBreakArray
, getBreak
, setBreakOn
, setBreakOff
, showBreakArray
) where
import Prelude -- See note [Why do we import Prelude here?]
import Control.Monad
import Data.Word
import GHC.Word
import GHC.Exts hiding (extendWord8#, narrowWord8#)
import GHC.IO ( IO(..) )
import System.IO.Unsafe ( unsafeDupablePerformIO )
#if MIN_VERSION_base(4,16,0)
import GHC.Base (extendWord8#, narrowWord8#)
#else
narrowWord8#, extendWord8# :: Word# -> Word#
narrowWord8# w = w
extendWord8# w = w
{-# INLINE narrowWord8# #-}
{-# INLINE extendWord8# #-}
#endif
data BreakArray = BA (MutableByteArray# RealWorld)
breakOff, breakOn :: Word8
breakOn = 1
breakOff = 0
showBreakArray :: BreakArray -> IO ()
showBreakArray array = do
forM_ [0 .. (size array - 1)] $ \i -> do
val <- readBreakArray array i
putStr $ ' ' : show val
putStr "\n"
setBreakOn :: BreakArray -> Int -> IO Bool
setBreakOn array index
| safeIndex array index = do
writeBreakArray array index breakOn
return True
| otherwise = return False
setBreakOff :: BreakArray -> Int -> IO Bool
setBreakOff array index
| safeIndex array index = do
writeBreakArray array index breakOff
return True
| otherwise = return False
getBreak :: BreakArray -> Int -> IO (Maybe Word8)
getBreak array index
| safeIndex array index = do
val <- readBreakArray array index
return $ Just val
| otherwise = return Nothing
safeIndex :: BreakArray -> Int -> Bool
safeIndex array index = index < size array && index >= 0
size :: BreakArray -> Int
size (BA array) = size
where
-- We want to keep this operation pure. The mutable byte array
-- is never resized so this is safe.
size = unsafeDupablePerformIO $ sizeofMutableByteArray array
sizeofMutableByteArray :: MutableByteArray# RealWorld -> IO Int
sizeofMutableByteArray arr =
IO $ \s -> case getSizeofMutableByteArray# arr s of
(# s', n# #) -> (# s', I# n# #)
allocBA :: Int -> IO BreakArray
allocBA (I# sz) = IO $ \s1 ->
case newByteArray# sz s1 of { (# s2, array #) -> (# s2, BA array #) }
-- create a new break array and initialise elements to zero
newBreakArray :: Int -> IO BreakArray
newBreakArray entries@(I# sz) = do
BA array <- allocBA entries
case breakOff of
W8# off -> do
let loop n | isTrue# (n ==# sz) = return ()
| otherwise = do writeBA# array n (extendWord8# off); loop (n +# 1#)
loop 0#
return $ BA array
writeBA# :: MutableByteArray# RealWorld -> Int# -> Word# -> IO ()
writeBA# array i word = IO $ \s ->
case writeWord8Array# array i word s of { s -> (# s, () #) }
writeBreakArray :: BreakArray -> Int -> Word8 -> IO ()
writeBreakArray (BA array) (I# i) (W8# word) = writeBA# array i (extendWord8# word)
readBA# :: MutableByteArray# RealWorld -> Int# -> IO Word8
readBA# array i = IO $ \s ->
case readWord8Array# array i s of { (# s, c #) -> (# s, W8# (narrowWord8# c) #) }
readBreakArray :: BreakArray -> Int -> IO Word8
readBreakArray (BA array) (I# i) = readBA# array i
|
