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discussion of this change. Boy are my fingers tired. ;-) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45411 91177308-0d34-0410-b5e6-96231b3b80d8
97 lines
4.1 KiB
C++
97 lines
4.1 KiB
C++
//===-- JITMemoryManager.h - Interface JIT uses to Allocate Mem -*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the JITMemoryManagerInterface
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_EXECUTION_ENGINE_JIT_MEMMANAGER_H
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#define LLVM_EXECUTION_ENGINE_JIT_MEMMANAGER_H
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#include "llvm/Support/DataTypes.h"
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namespace llvm {
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class Function;
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/// JITMemoryManager - This interface is used by the JIT to allocate and manage
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/// memory for the code generated by the JIT. This can be reimplemented by
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/// clients that have a strong desire to control how the layout of JIT'd memory
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/// works.
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class JITMemoryManager {
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protected:
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bool HasGOT;
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public:
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JITMemoryManager() : HasGOT(false) {}
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virtual ~JITMemoryManager();
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/// CreateDefaultMemManager - This is used to create the default
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/// JIT Memory Manager if the client does not provide one to the JIT.
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static JITMemoryManager *CreateDefaultMemManager();
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//===--------------------------------------------------------------------===//
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// Global Offset Table Management
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//===--------------------------------------------------------------------===//
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/// AllocateGOT - If the current table requires a Global Offset Table, this
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/// method is invoked to allocate it. This method is required to set HasGOT
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/// to true.
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virtual void AllocateGOT() = 0;
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/// isManagingGOT - Return true if the AllocateGOT method is called.
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///
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bool isManagingGOT() const {
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return HasGOT;
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}
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/// getGOTBase - If this is managing a Global Offset Table, this method should
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/// return a pointer to its base.
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virtual unsigned char *getGOTBase() const = 0;
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//===--------------------------------------------------------------------===//
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// Main Allocation Functions
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//===--------------------------------------------------------------------===//
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/// startFunctionBody - When we start JITing a function, the JIT calls this
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/// method to allocate a block of free RWX memory, which returns a pointer to
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/// it. The JIT doesn't know ahead of time how much space it will need to
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/// emit the function, so it doesn't pass in the size. Instead, this method
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/// is required to pass back a "valid size". The JIT will be careful to not
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/// write more than the returned ActualSize bytes of memory.
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virtual unsigned char *startFunctionBody(const Function *F,
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uintptr_t &ActualSize) = 0;
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/// allocateStub - This method is called by the JIT to allocate space for a
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/// function stub (used to handle limited branch displacements) while it is
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/// JIT compiling a function. For example, if foo calls bar, and if bar
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/// either needs to be lazily compiled or is a native function that exists too
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/// far away from the call site to work, this method will be used to make a
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/// thunk for it. The stub should be "close" to the current function body,
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/// but should not be included in the 'actualsize' returned by
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/// startFunctionBody.
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virtual unsigned char *allocateStub(unsigned StubSize, unsigned Alignment) =0;
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/// endFunctionBody - This method is called when the JIT is done codegen'ing
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/// the specified function. At this point we know the size of the JIT
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/// compiled function. This passes in FunctionStart (which was returned by
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/// the startFunctionBody method) and FunctionEnd which is a pointer to the
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/// actual end of the function. This method should mark the space allocated
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/// and remember where it is in case the client wants to deallocate it.
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virtual void endFunctionBody(const Function *F, unsigned char *FunctionStart,
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unsigned char *FunctionEnd) = 0;
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/// deallocateMemForFunction - Free JIT memory for the specified function.
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/// This is never called when the JIT is currently emitting a function.
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virtual void deallocateMemForFunction(const Function *F) = 0;
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};
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} // end namespace llvm.
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#endif
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