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
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
//===- SectionMemoryManager.cpp - Memory manager for MCJIT/RtDyld *- C++ -*-==//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the section-based memory manager used by the MCJIT
// execution engine and RuntimeDyld
//
//===----------------------------------------------------------------------===//
#include "llvm/Config/config.h"
#include "llvm/ExecutionEngine/SectionMemoryManager.h"
#include "llvm/Support/MathExtras.h"
namespace llvm {
uint8_t *SectionMemoryManager::allocateDataSection(uintptr_t Size,
unsigned Alignment,
unsigned SectionID,
StringRef SectionName,
bool IsReadOnly) {
if (IsReadOnly)
return allocateSection(RODataMem, Size, Alignment);
return allocateSection(RWDataMem, Size, Alignment);
}
uint8_t *SectionMemoryManager::allocateCodeSection(uintptr_t Size,
unsigned Alignment,
unsigned SectionID,
StringRef SectionName) {
return allocateSection(CodeMem, Size, Alignment);
}
uint8_t *SectionMemoryManager::allocateSection(MemoryGroup &MemGroup,
uintptr_t Size,
unsigned Alignment) {
if (!Alignment)
Alignment = 16;
assert(!(Alignment & (Alignment - 1)) && "Alignment must be a power of two.");
uintptr_t RequiredSize = Alignment * ((Size + Alignment - 1)/Alignment + 1);
uintptr_t Addr = 0;
// Look in the list of free memory regions and use a block there if one
// is available.
for (int i = 0, e = MemGroup.FreeMem.size(); i != e; ++i) {
sys::MemoryBlock &MB = MemGroup.FreeMem[i];
if (MB.size() >= RequiredSize) {
Addr = (uintptr_t)MB.base();
uintptr_t EndOfBlock = Addr + MB.size();
// Align the address.
Addr = (Addr + Alignment - 1) & ~(uintptr_t)(Alignment - 1);
// Store cutted free memory block.
MemGroup.FreeMem[i] = sys::MemoryBlock((void*)(Addr + Size),
EndOfBlock - Addr - Size);
return (uint8_t*)Addr;
}
}
// No pre-allocated free block was large enough. Allocate a new memory region.
// Note that all sections get allocated as read-write. The permissions will
// be updated later based on memory group.
//
// FIXME: It would be useful to define a default allocation size (or add
// it as a constructor parameter) to minimize the number of allocations.
//
// FIXME: Initialize the Near member for each memory group to avoid
// interleaving.
std::error_code ec;
sys::MemoryBlock MB = sys::Memory::allocateMappedMemory(RequiredSize,
&MemGroup.Near,
sys::Memory::MF_READ |
sys::Memory::MF_WRITE,
ec);
if (ec) {
// FIXME: Add error propagation to the interface.
return nullptr;
}
// Save this address as the basis for our next request
MemGroup.Near = MB;
MemGroup.AllocatedMem.push_back(MB);
Addr = (uintptr_t)MB.base();
uintptr_t EndOfBlock = Addr + MB.size();
// Align the address.
Addr = (Addr + Alignment - 1) & ~(uintptr_t)(Alignment - 1);
// The allocateMappedMemory may allocate much more memory than we need. In
// this case, we store the unused memory as a free memory block.
unsigned FreeSize = EndOfBlock-Addr-Size;
if (FreeSize > 16)
MemGroup.FreeMem.push_back(sys::MemoryBlock((void*)(Addr + Size), FreeSize));
// Return aligned address
return (uint8_t*)Addr;
}
bool SectionMemoryManager::finalizeMemory(std::string *ErrMsg)
{
// FIXME: Should in-progress permissions be reverted if an error occurs?
std::error_code ec;
// Don't allow free memory blocks to be used after setting protection flags.
CodeMem.FreeMem.clear();
// Make code memory executable.
ec = applyMemoryGroupPermissions(CodeMem,
sys::Memory::MF_READ | sys::Memory::MF_EXEC);
if (ec) {
if (ErrMsg) {
*ErrMsg = ec.message();
}
return true;
}
// Don't allow free memory blocks to be used after setting protection flags.
RODataMem.FreeMem.clear();
// Make read-only data memory read-only.
ec = applyMemoryGroupPermissions(RODataMem,
sys::Memory::MF_READ | sys::Memory::MF_EXEC);
if (ec) {
if (ErrMsg) {
*ErrMsg = ec.message();
}
return true;
}
// Read-write data memory already has the correct permissions
// Some platforms with separate data cache and instruction cache require
// explicit cache flush, otherwise JIT code manipulations (like resolved
// relocations) will get to the data cache but not to the instruction cache.
invalidateInstructionCache();
return false;
}
std::error_code
SectionMemoryManager::applyMemoryGroupPermissions(MemoryGroup &MemGroup,
unsigned Permissions) {
for (int i = 0, e = MemGroup.AllocatedMem.size(); i != e; ++i) {
std::error_code ec;
ec =
sys::Memory::protectMappedMemory(MemGroup.AllocatedMem[i], Permissions);
if (ec) {
return ec;
}
}
return std::error_code();
}
void SectionMemoryManager::invalidateInstructionCache() {
for (int i = 0, e = CodeMem.AllocatedMem.size(); i != e; ++i)
sys::Memory::InvalidateInstructionCache(CodeMem.AllocatedMem[i].base(),
CodeMem.AllocatedMem[i].size());
}
SectionMemoryManager::~SectionMemoryManager() {
for (unsigned i = 0, e = CodeMem.AllocatedMem.size(); i != e; ++i)
sys::Memory::releaseMappedMemory(CodeMem.AllocatedMem[i]);
for (unsigned i = 0, e = RWDataMem.AllocatedMem.size(); i != e; ++i)
sys::Memory::releaseMappedMemory(RWDataMem.AllocatedMem[i]);
for (unsigned i = 0, e = RODataMem.AllocatedMem.size(); i != e; ++i)
sys::Memory::releaseMappedMemory(RODataMem.AllocatedMem[i]);
}
} // namespace llvm
|
