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//===-- JITMemoryManager.h - Interface JIT uses to Allocate Mem -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_EXECUTIONENGINE_JITMEMORYMANAGER_H
#define LLVM_EXECUTIONENGINE_JITMEMORYMANAGER_H
#include "llvm/ExecutionEngine/RuntimeDyld.h"
#include "llvm/Support/DataTypes.h"
#include <string>
namespace llvm {
class Function;
class GlobalValue;
/// JITMemoryManager - This interface is used by the JIT to allocate and manage
/// memory for the code generated by the JIT. This can be reimplemented by
/// clients that have a strong desire to control how the layout of JIT'd memory
/// works.
class JITMemoryManager : public RTDyldMemoryManager {
protected:
bool HasGOT;
public:
JITMemoryManager() : HasGOT(false) {}
virtual ~JITMemoryManager();
/// CreateDefaultMemManager - This is used to create the default
/// JIT Memory Manager if the client does not provide one to the JIT.
static JITMemoryManager *CreateDefaultMemManager();
/// setMemoryWritable - When code generation is in progress,
/// the code pages may need permissions changed.
virtual void setMemoryWritable() = 0;
/// setMemoryExecutable - When code generation is done and we're ready to
/// start execution, the code pages may need permissions changed.
virtual void setMemoryExecutable() = 0;
/// setPoisonMemory - Setting this flag to true makes the memory manager
/// garbage values over freed memory. This is useful for testing and
/// debugging, and may be turned on by default in debug mode.
virtual void setPoisonMemory(bool poison) = 0;
//===--------------------------------------------------------------------===//
// Global Offset Table Management
//===--------------------------------------------------------------------===//
/// AllocateGOT - If the current table requires a Global Offset Table, this
/// method is invoked to allocate it. This method is required to set HasGOT
/// to true.
virtual void AllocateGOT() = 0;
/// isManagingGOT - Return true if the AllocateGOT method is called.
bool isManagingGOT() const {
return HasGOT;
}
/// getGOTBase - If this is managing a Global Offset Table, this method should
/// return a pointer to its base.
virtual uint8_t *getGOTBase() const = 0;
//===--------------------------------------------------------------------===//
// Main Allocation Functions
//===--------------------------------------------------------------------===//
/// startFunctionBody - When we start JITing a function, the JIT calls this
/// method to allocate a block of free RWX memory, which returns a pointer to
/// it. If the JIT wants to request a block of memory of at least a certain
/// size, it passes that value as ActualSize, and this method returns a block
/// with at least that much space. If the JIT doesn't know ahead of time how
/// much space it will need to emit the function, it passes 0 for the
/// ActualSize. In either case, this method is required to pass back the size
/// of the allocated block through ActualSize. The JIT will be careful to
/// not write more than the returned ActualSize bytes of memory.
virtual uint8_t *startFunctionBody(const Function *F,
uintptr_t &ActualSize) = 0;
/// allocateStub - This method is called by the JIT to allocate space for a
/// function stub (used to handle limited branch displacements) while it is
/// JIT compiling a function. For example, if foo calls bar, and if bar
/// either needs to be lazily compiled or is a native function that exists too
/// far away from the call site to work, this method will be used to make a
/// thunk for it. The stub should be "close" to the current function body,
/// but should not be included in the 'actualsize' returned by
/// startFunctionBody.
virtual uint8_t *allocateStub(const GlobalValue* F, unsigned StubSize,
unsigned Alignment) = 0;
/// endFunctionBody - This method is called when the JIT is done codegen'ing
/// the specified function. At this point we know the size of the JIT
/// compiled function. This passes in FunctionStart (which was returned by
/// the startFunctionBody method) and FunctionEnd which is a pointer to the
/// actual end of the function. This method should mark the space allocated
/// and remember where it is in case the client wants to deallocate it.
virtual void endFunctionBody(const Function *F, uint8_t *FunctionStart,
uint8_t *FunctionEnd) = 0;
/// allocateSpace - Allocate a memory block of the given size. This method
/// cannot be called between calls to startFunctionBody and endFunctionBody.
virtual uint8_t *allocateSpace(intptr_t Size, unsigned Alignment) = 0;
/// allocateGlobal - Allocate memory for a global.
virtual uint8_t *allocateGlobal(uintptr_t Size, unsigned Alignment) = 0;
/// deallocateFunctionBody - Free the specified function body. The argument
/// must be the return value from a call to startFunctionBody() that hasn't
/// been deallocated yet. This is never called when the JIT is currently
/// emitting a function.
virtual void deallocateFunctionBody(void *Body) = 0;
/// CheckInvariants - For testing only. Return true if all internal
/// invariants are preserved, or return false and set ErrorStr to a helpful
/// error message.
virtual bool CheckInvariants(std::string &) {
return true;
}
/// GetDefaultCodeSlabSize - For testing only. Returns DefaultCodeSlabSize
/// from DefaultJITMemoryManager.
virtual size_t GetDefaultCodeSlabSize() {
return 0;
}
/// GetDefaultDataSlabSize - For testing only. Returns DefaultCodeSlabSize
/// from DefaultJITMemoryManager.
virtual size_t GetDefaultDataSlabSize() {
return 0;
}
/// GetDefaultStubSlabSize - For testing only. Returns DefaultCodeSlabSize
/// from DefaultJITMemoryManager.
virtual size_t GetDefaultStubSlabSize() {
return 0;
}
/// GetNumCodeSlabs - For testing only. Returns the number of MemoryBlocks
/// allocated for code.
virtual unsigned GetNumCodeSlabs() {
return 0;
}
/// GetNumDataSlabs - For testing only. Returns the number of MemoryBlocks
/// allocated for data.
virtual unsigned GetNumDataSlabs() {
return 0;
}
/// GetNumStubSlabs - For testing only. Returns the number of MemoryBlocks
/// allocated for function stubs.
virtual unsigned GetNumStubSlabs() {
return 0;
}
};
} // end namespace llvm.
#endif
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