1 //===-- JITMemoryManager.h - Interface JIT uses to Allocate Mem -*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #ifndef LLVM_EXECUTION_ENGINE_JIT_MEMMANAGER_H
11 #define LLVM_EXECUTION_ENGINE_JIT_MEMMANAGER_H
13 #include "llvm/ExecutionEngine/RuntimeDyld.h"
14 #include "llvm/Support/DataTypes.h"
23 /// JITMemoryManager - This interface is used by the JIT to allocate and manage
24 /// memory for the code generated by the JIT. This can be reimplemented by
25 /// clients that have a strong desire to control how the layout of JIT'd memory
27 class JITMemoryManager : public RTDyldMemoryManager {
32 JITMemoryManager() : HasGOT(false) {}
33 virtual ~JITMemoryManager();
35 /// CreateDefaultMemManager - This is used to create the default
36 /// JIT Memory Manager if the client does not provide one to the JIT.
37 static JITMemoryManager *CreateDefaultMemManager();
39 /// setMemoryWritable - When code generation is in progress,
40 /// the code pages may need permissions changed.
41 virtual void setMemoryWritable() = 0;
43 /// setMemoryExecutable - When code generation is done and we're ready to
44 /// start execution, the code pages may need permissions changed.
45 virtual void setMemoryExecutable() = 0;
47 /// setPoisonMemory - Setting this flag to true makes the memory manager
48 /// garbage values over freed memory. This is useful for testing and
49 /// debugging, and may be turned on by default in debug mode.
50 virtual void setPoisonMemory(bool poison) = 0;
52 //===--------------------------------------------------------------------===//
53 // Global Offset Table Management
54 //===--------------------------------------------------------------------===//
56 /// AllocateGOT - If the current table requires a Global Offset Table, this
57 /// method is invoked to allocate it. This method is required to set HasGOT
59 virtual void AllocateGOT() = 0;
61 /// isManagingGOT - Return true if the AllocateGOT method is called.
62 bool isManagingGOT() const {
66 /// getGOTBase - If this is managing a Global Offset Table, this method should
67 /// return a pointer to its base.
68 virtual uint8_t *getGOTBase() const = 0;
70 //===--------------------------------------------------------------------===//
71 // Main Allocation Functions
72 //===--------------------------------------------------------------------===//
74 /// startFunctionBody - When we start JITing a function, the JIT calls this
75 /// method to allocate a block of free RWX memory, which returns a pointer to
76 /// it. If the JIT wants to request a block of memory of at least a certain
77 /// size, it passes that value as ActualSize, and this method returns a block
78 /// with at least that much space. If the JIT doesn't know ahead of time how
79 /// much space it will need to emit the function, it passes 0 for the
80 /// ActualSize. In either case, this method is required to pass back the size
81 /// of the allocated block through ActualSize. The JIT will be careful to
82 /// not write more than the returned ActualSize bytes of memory.
83 virtual uint8_t *startFunctionBody(const Function *F,
84 uintptr_t &ActualSize) = 0;
86 /// allocateStub - This method is called by the JIT to allocate space for a
87 /// function stub (used to handle limited branch displacements) while it is
88 /// JIT compiling a function. For example, if foo calls bar, and if bar
89 /// either needs to be lazily compiled or is a native function that exists too
90 /// far away from the call site to work, this method will be used to make a
91 /// thunk for it. The stub should be "close" to the current function body,
92 /// but should not be included in the 'actualsize' returned by
93 /// startFunctionBody.
94 virtual uint8_t *allocateStub(const GlobalValue* F, unsigned StubSize,
95 unsigned Alignment) = 0;
97 /// endFunctionBody - This method is called when the JIT is done codegen'ing
98 /// the specified function. At this point we know the size of the JIT
99 /// compiled function. This passes in FunctionStart (which was returned by
100 /// the startFunctionBody method) and FunctionEnd which is a pointer to the
101 /// actual end of the function. This method should mark the space allocated
102 /// and remember where it is in case the client wants to deallocate it.
103 virtual void endFunctionBody(const Function *F, uint8_t *FunctionStart,
104 uint8_t *FunctionEnd) = 0;
106 /// allocateSpace - Allocate a memory block of the given size. This method
107 /// cannot be called between calls to startFunctionBody and endFunctionBody.
108 virtual uint8_t *allocateSpace(intptr_t Size, unsigned Alignment) = 0;
110 /// allocateGlobal - Allocate memory for a global.
111 virtual uint8_t *allocateGlobal(uintptr_t Size, unsigned Alignment) = 0;
113 /// deallocateFunctionBody - Free the specified function body. The argument
114 /// must be the return value from a call to startFunctionBody() that hasn't
115 /// been deallocated yet. This is never called when the JIT is currently
116 /// emitting a function.
117 virtual void deallocateFunctionBody(void *Body) = 0;
119 /// startExceptionTable - When we finished JITing the function, if exception
120 /// handling is set, we emit the exception table.
121 virtual uint8_t* startExceptionTable(const Function* F,
122 uintptr_t &ActualSize) = 0;
124 /// endExceptionTable - This method is called when the JIT is done emitting
125 /// the exception table.
126 virtual void endExceptionTable(const Function *F, uint8_t *TableStart,
127 uint8_t *TableEnd, uint8_t* FrameRegister) = 0;
129 /// deallocateExceptionTable - Free the specified exception table's memory.
130 /// The argument must be the return value from a call to startExceptionTable()
131 /// that hasn't been deallocated yet. This is never called when the JIT is
132 /// currently emitting an exception table.
133 virtual void deallocateExceptionTable(void *ET) = 0;
135 /// CheckInvariants - For testing only. Return true if all internal
136 /// invariants are preserved, or return false and set ErrorStr to a helpful
138 virtual bool CheckInvariants(std::string &) {
142 /// GetDefaultCodeSlabSize - For testing only. Returns DefaultCodeSlabSize
143 /// from DefaultJITMemoryManager.
144 virtual size_t GetDefaultCodeSlabSize() {
148 /// GetDefaultDataSlabSize - For testing only. Returns DefaultCodeSlabSize
149 /// from DefaultJITMemoryManager.
150 virtual size_t GetDefaultDataSlabSize() {
154 /// GetDefaultStubSlabSize - For testing only. Returns DefaultCodeSlabSize
155 /// from DefaultJITMemoryManager.
156 virtual size_t GetDefaultStubSlabSize() {
160 /// GetNumCodeSlabs - For testing only. Returns the number of MemoryBlocks
161 /// allocated for code.
162 virtual unsigned GetNumCodeSlabs() {
166 /// GetNumDataSlabs - For testing only. Returns the number of MemoryBlocks
167 /// allocated for data.
168 virtual unsigned GetNumDataSlabs() {
172 /// GetNumStubSlabs - For testing only. Returns the number of MemoryBlocks
173 /// allocated for function stubs.
174 virtual unsigned GetNumStubSlabs() {
179 } // end namespace llvm.