SectionMemoryManager.h revision 249259 
1//===- SectionMemoryManager.h - 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 contains the declaration of a section-based memory manager used by
11// the MCJIT execution engine and RuntimeDyld.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_EXECUTIONENGINE_SECTIONMEMORYMANAGER_H
16#define LLVM_EXECUTIONENGINE_SECTIONMEMORYMANAGER_H
17
18#include "llvm/ADT/SmallVector.h"
19#include "llvm/ExecutionEngine/JITMemoryManager.h"
20#include "llvm/Support/ErrorHandling.h"
21#include "llvm/Support/Memory.h"
22
23namespace llvm {
24
25/// This is a simple memory manager which implements the methods called by
26/// the RuntimeDyld class to allocate memory for section-based loading of
27/// objects, usually those generated by the MCJIT execution engine.
28///
29/// This memory manager allocates all section memory as read-write.  The
30/// RuntimeDyld will copy JITed section memory into these allocated blocks
31/// and perform any necessary linking and relocations.
32///
33/// Any client using this memory manager MUST ensure that section-specific
34/// page permissions have been applied before attempting to execute functions
35/// in the JITed object.  Permissions can be applied either by calling
36/// MCJIT::finalizeObject or by calling SectionMemoryManager::applyPermissions
37/// directly.  Clients of MCJIT should call MCJIT::finalizeObject.
38class SectionMemoryManager : public JITMemoryManager {
39  SectionMemoryManager(const SectionMemoryManager&) LLVM_DELETED_FUNCTION;
40  void operator=(const SectionMemoryManager&) LLVM_DELETED_FUNCTION;
41
42public:
43  SectionMemoryManager() { }
44  virtual ~SectionMemoryManager();
45
46  /// \brief Allocates a memory block of (at least) the given size suitable for
47  /// executable code.
48  ///
49  /// The value of \p Alignment must be a power of two.  If \p Alignment is zero
50  /// a default alignment of 16 will be used.
51  virtual uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment,
52                                       unsigned SectionID);
53
54  /// \brief Allocates a memory block of (at least) the given size suitable for
55  /// executable code.
56  ///
57  /// The value of \p Alignment must be a power of two.  If \p Alignment is zero
58  /// a default alignment of 16 will be used.
59  virtual uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment,
60                                       unsigned SectionID,
61                                       bool isReadOnly);
62
63  /// \brief Applies section-specific memory permissions.
64  ///
65  /// This method is called when object loading is complete and section page
66  /// permissions can be applied.  It is up to the memory manager implementation
67  /// to decide whether or not to act on this method.  The memory manager will
68  /// typically allocate all sections as read-write and then apply specific
69  /// permissions when this method is called.  Code sections cannot be executed
70  /// until this function has been called.
71  ///
72  /// \returns true if an error occurred, false otherwise.
73  virtual bool applyPermissions(std::string *ErrMsg = 0);
74
75  /// This method returns the address of the specified function. As such it is
76  /// only useful for resolving library symbols, not code generated symbols.
77  ///
78  /// If \p AbortOnFailure is false and no function with the given name is
79  /// found, this function returns a null pointer. Otherwise, it prints a
80  /// message to stderr and aborts.
81  virtual void *getPointerToNamedFunction(const std::string &Name,
82                                          bool AbortOnFailure = true);
83
84  /// \brief Invalidate instruction cache for code sections.
85  ///
86  /// Some platforms with separate data cache and instruction cache require
87  /// explicit cache flush, otherwise JIT code manipulations (like resolved
88  /// relocations) will get to the data cache but not to the instruction cache.
89  ///
90  /// This method is not called by RuntimeDyld or MCJIT during the load
91  /// process.  Clients may call this function when needed.  See the lli
92  /// tool for example use.
93  virtual void invalidateInstructionCache();
94
95private:
96  struct MemoryGroup {
97      SmallVector<sys::MemoryBlock, 16> AllocatedMem;
98      SmallVector<sys::MemoryBlock, 16> FreeMem;
99      sys::MemoryBlock Near;
100  };
101
102  uint8_t *allocateSection(MemoryGroup &MemGroup, uintptr_t Size,
103                           unsigned Alignment);
104
105  error_code applyMemoryGroupPermissions(MemoryGroup &MemGroup,
106                                         unsigned Permissions);
107
108  MemoryGroup CodeMem;
109  MemoryGroup RWDataMem;
110  MemoryGroup RODataMem;
111
112public:
113  ///
114  /// Functions below are not used by MCJIT or RuntimeDyld, but must be
115  /// implemented because they are declared as pure virtuals in the base class.
116  ///
117
118  virtual void setMemoryWritable() {
119    llvm_unreachable("Unexpected call!");
120  }
121  virtual void setMemoryExecutable() {
122    llvm_unreachable("Unexpected call!");
123  }
124  virtual void setPoisonMemory(bool poison) {
125    llvm_unreachable("Unexpected call!");
126  }
127  virtual void AllocateGOT() {
128    llvm_unreachable("Unexpected call!");
129  }
130  virtual uint8_t *getGOTBase() const {
131    llvm_unreachable("Unexpected call!");
132    return 0;
133  }
134  virtual uint8_t *startFunctionBody(const Function *F,
135                                     uintptr_t &ActualSize){
136    llvm_unreachable("Unexpected call!");
137    return 0;
138  }
139  virtual uint8_t *allocateStub(const GlobalValue *F, unsigned StubSize,
140                                unsigned Alignment) {
141    llvm_unreachable("Unexpected call!");
142    return 0;
143  }
144  virtual void endFunctionBody(const Function *F, uint8_t *FunctionStart,
145                               uint8_t *FunctionEnd) {
146    llvm_unreachable("Unexpected call!");
147  }
148  virtual uint8_t *allocateSpace(intptr_t Size, unsigned Alignment) {
149    llvm_unreachable("Unexpected call!");
150    return 0;
151  }
152  virtual uint8_t *allocateGlobal(uintptr_t Size, unsigned Alignment) {
153    llvm_unreachable("Unexpected call!");
154    return 0;
155  }
156  virtual void deallocateFunctionBody(void *Body) {
157    llvm_unreachable("Unexpected call!");
158  }
159  virtual uint8_t *startExceptionTable(const Function *F,
160                                       uintptr_t &ActualSize) {
161    llvm_unreachable("Unexpected call!");
162    return 0;
163  }
164  virtual void endExceptionTable(const Function *F, uint8_t *TableStart,
165                                 uint8_t *TableEnd, uint8_t *FrameRegister) {
166    llvm_unreachable("Unexpected call!");
167  }
168  virtual void deallocateExceptionTable(void *ET) {
169    llvm_unreachable("Unexpected call!");
170  }
171};
172
173}
174
175#endif // LLVM_EXECUTION_ENGINE_SECTION_MEMORY_MANAGER_H
176
177