Mercurial > hg > CbC > CbC_llvm

comparison lib/ExecutionEngine/SectionMemoryManager.cpp @ 83:60c9769439b8 LLVM3.7

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
LLVM 3.7
author Tatsuki IHA <e125716@ie.u-ryukyu.ac.jp>
date Wed, 18 Feb 2015 14:55:36 +0900
parents
children afa8332a0e37
comparison
equal deleted inserted replaced
78:af83660cff7b 83:60c9769439b8
1 //===- SectionMemoryManager.cpp - Memory manager for MCJIT/RtDyld *- C++ -*-==//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements the section-based memory manager used by the MCJIT
11 // execution engine and RuntimeDyld
12 //
13 //===----------------------------------------------------------------------===//
14
15 #include "llvm/Config/config.h"
16 #include "llvm/ExecutionEngine/SectionMemoryManager.h"
17 #include "llvm/Support/MathExtras.h"
18
19 namespace llvm {
20
21 uint8_t *SectionMemoryManager::allocateDataSection(uintptr_t Size,
22 unsigned Alignment,
23 unsigned SectionID,
24 StringRef SectionName,
25 bool IsReadOnly) {
26 if (IsReadOnly)
27 return allocateSection(RODataMem, Size, Alignment);
28 return allocateSection(RWDataMem, Size, Alignment);
29 }
30
31 uint8_t *SectionMemoryManager::allocateCodeSection(uintptr_t Size,
32 unsigned Alignment,
33 unsigned SectionID,
34 StringRef SectionName) {
35 return allocateSection(CodeMem, Size, Alignment);
36 }
37
38 uint8_t *SectionMemoryManager::allocateSection(MemoryGroup &MemGroup,
39 uintptr_t Size,
40 unsigned Alignment) {
41 if (!Alignment)
42 Alignment = 16;
43
44 assert(!(Alignment & (Alignment - 1)) && "Alignment must be a power of two.");
45
46 uintptr_t RequiredSize = Alignment * ((Size + Alignment - 1)/Alignment + 1);
47 uintptr_t Addr = 0;
48
49 // Look in the list of free memory regions and use a block there if one
50 // is available.
51 for (int i = 0, e = MemGroup.FreeMem.size(); i != e; ++i) {
52 sys::MemoryBlock &MB = MemGroup.FreeMem[i];
53 if (MB.size() >= RequiredSize) {
54 Addr = (uintptr_t)MB.base();
55 uintptr_t EndOfBlock = Addr + MB.size();
56 // Align the address.
57 Addr = (Addr + Alignment - 1) & ~(uintptr_t)(Alignment - 1);
58 // Store cutted free memory block.
59 MemGroup.FreeMem[i] = sys::MemoryBlock((void*)(Addr + Size),
60 EndOfBlock - Addr - Size);
61 return (uint8_t*)Addr;
62 }
63 }
64
65 // No pre-allocated free block was large enough. Allocate a new memory region.
66 // Note that all sections get allocated as read-write. The permissions will
67 // be updated later based on memory group.
68 //
69 // FIXME: It would be useful to define a default allocation size (or add
70 // it as a constructor parameter) to minimize the number of allocations.
71 //
72 // FIXME: Initialize the Near member for each memory group to avoid
73 // interleaving.
74 std::error_code ec;
75 sys::MemoryBlock MB = sys::Memory::allocateMappedMemory(RequiredSize,
76 &MemGroup.Near,
77 sys::Memory::MF_READ |
78 sys::Memory::MF_WRITE,
79 ec);
80 if (ec) {
81 // FIXME: Add error propagation to the interface.
82 return nullptr;
83 }
84
85 // Save this address as the basis for our next request
86 MemGroup.Near = MB;
87
88 MemGroup.AllocatedMem.push_back(MB);
89 Addr = (uintptr_t)MB.base();
90 uintptr_t EndOfBlock = Addr + MB.size();
91
92 // Align the address.
93 Addr = (Addr + Alignment - 1) & ~(uintptr_t)(Alignment - 1);
94
95 // The allocateMappedMemory may allocate much more memory than we need. In
96 // this case, we store the unused memory as a free memory block.
97 unsigned FreeSize = EndOfBlock-Addr-Size;
98 if (FreeSize > 16)
99 MemGroup.FreeMem.push_back(sys::MemoryBlock((void*)(Addr + Size), FreeSize));
100
101 // Return aligned address
102 return (uint8_t*)Addr;
103 }
104
105 bool SectionMemoryManager::finalizeMemory(std::string *ErrMsg)
106 {
107 // FIXME: Should in-progress permissions be reverted if an error occurs?
108 std::error_code ec;
109
110 // Don't allow free memory blocks to be used after setting protection flags.
111 CodeMem.FreeMem.clear();
112
113 // Make code memory executable.
114 ec = applyMemoryGroupPermissions(CodeMem,
115 sys::Memory::MF_READ | sys::Memory::MF_EXEC);
116 if (ec) {
117 if (ErrMsg) {
118 *ErrMsg = ec.message();
119 }
120 return true;
121 }
122
123 // Don't allow free memory blocks to be used after setting protection flags.
124 RODataMem.FreeMem.clear();
125
126 // Make read-only data memory read-only.
127 ec = applyMemoryGroupPermissions(RODataMem,
128 sys::Memory::MF_READ | sys::Memory::MF_EXEC);
129 if (ec) {
130 if (ErrMsg) {
131 *ErrMsg = ec.message();
132 }
133 return true;
134 }
135
136 // Read-write data memory already has the correct permissions
137
138 // Some platforms with separate data cache and instruction cache require
139 // explicit cache flush, otherwise JIT code manipulations (like resolved
140 // relocations) will get to the data cache but not to the instruction cache.
141 invalidateInstructionCache();
142
143 return false;
144 }
145
146 std::error_code
147 SectionMemoryManager::applyMemoryGroupPermissions(MemoryGroup &MemGroup,
148 unsigned Permissions) {
149
150 for (int i = 0, e = MemGroup.AllocatedMem.size(); i != e; ++i) {
151 std::error_code ec;
152 ec =
153 sys::Memory::protectMappedMemory(MemGroup.AllocatedMem[i], Permissions);
154 if (ec) {
155 return ec;
156 }
157 }
158
159 return std::error_code();
160 }
161
162 void SectionMemoryManager::invalidateInstructionCache() {
163 for (int i = 0, e = CodeMem.AllocatedMem.size(); i != e; ++i)
164 sys::Memory::InvalidateInstructionCache(CodeMem.AllocatedMem[i].base(),
165 CodeMem.AllocatedMem[i].size());
166 }
167
168 SectionMemoryManager::~SectionMemoryManager() {
169 for (unsigned i = 0, e = CodeMem.AllocatedMem.size(); i != e; ++i)
170 sys::Memory::releaseMappedMemory(CodeMem.AllocatedMem[i]);
171 for (unsigned i = 0, e = RWDataMem.AllocatedMem.size(); i != e; ++i)
172 sys::Memory::releaseMappedMemory(RWDataMem.AllocatedMem[i]);
173 for (unsigned i = 0, e = RODataMem.AllocatedMem.size(); i != e; ++i)
174 sys::Memory::releaseMappedMemory(RODataMem.AllocatedMem[i]);
175 }
176
177 } // namespace llvm
178