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
126
127
128
129
130
131
132
133
134
135
136
137
|
using ARMeilleure.CodeGen;
using ARMeilleure.Memory;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Runtime.InteropServices;
namespace ARMeilleure.Translation
{
static class JitCache
{
private const int PageSize = 4 * 1024;
private const int PageMask = PageSize - 1;
private const int CodeAlignment = 4; // Bytes
private const int CacheSize = 2047 * 1024 * 1024;
private static ReservedRegion _jitRegion;
private static int _offset;
private static readonly List<JitCacheEntry> _cacheEntries = new List<JitCacheEntry>();
private static readonly object _lock = new object();
private static bool _initialized;
public static void Initialize(IJitMemoryAllocator allocator)
{
if (_initialized) return;
lock (_lock)
{
if (_initialized) return;
_jitRegion = new ReservedRegion(allocator, CacheSize);
if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
{
_jitRegion.ExpandIfNeeded(PageSize);
JitUnwindWindows.InstallFunctionTableHandler(_jitRegion.Pointer, CacheSize);
// The first page is used for the table based SEH structs.
_offset = PageSize;
}
_initialized = true;
}
}
public static IntPtr Map(CompiledFunction func)
{
byte[] code = func.Code;
lock (_lock)
{
Debug.Assert(_initialized);
int funcOffset = Allocate(code.Length);
IntPtr funcPtr = _jitRegion.Pointer + funcOffset;
Marshal.Copy(code, 0, funcPtr, code.Length);
ReprotectRange(funcOffset, code.Length);
Add(new JitCacheEntry(funcOffset, code.Length, func.UnwindInfo));
return funcPtr;
}
}
private static void ReprotectRange(int offset, int size)
{
// Map pages that are already full as RX.
// Map pages that are not full yet as RWX.
// On unix, the address must be page aligned.
int endOffs = offset + size;
int pageStart = offset & ~PageMask;
int pageEnd = endOffs & ~PageMask;
int fullPagesSize = pageEnd - pageStart;
if (fullPagesSize != 0)
{
_jitRegion.Block.MapAsRx((ulong)pageStart, (ulong)fullPagesSize);
}
int remaining = endOffs - pageEnd;
if (remaining != 0)
{
_jitRegion.Block.MapAsRwx((ulong)pageEnd, (ulong)remaining);
}
}
private static int Allocate(int codeSize)
{
codeSize = checked(codeSize + (CodeAlignment - 1)) & ~(CodeAlignment - 1);
int allocOffset = _offset;
_offset += codeSize;
_jitRegion.ExpandIfNeeded((ulong)_offset);
if ((ulong)(uint)_offset > CacheSize)
{
throw new OutOfMemoryException();
}
return allocOffset;
}
private static void Add(JitCacheEntry entry)
{
_cacheEntries.Add(entry);
}
public static bool TryFind(int offset, out JitCacheEntry entry)
{
lock (_lock)
{
foreach (JitCacheEntry cacheEntry in _cacheEntries)
{
int endOffset = cacheEntry.Offset + cacheEntry.Size;
if (offset >= cacheEntry.Offset && offset < endOffset)
{
entry = cacheEntry;
return true;
}
}
}
entry = default;
return false;
}
}
}
|
