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//===- SectionMemoryManager.h - Memory manager for MCJIT/RtDyld -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the declaration of a section-based memory manager used by
// the MCJIT execution engine and RuntimeDyld.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_EXECUTIONENGINE_SECTIONMEMORYMANAGER_H
#define LLVM_EXECUTIONENGINE_SECTIONMEMORYMANAGER_H
#include "llvm/ADT/SmallVector.h"
#include "llvm/ExecutionEngine/JITMemoryManager.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Memory.h"
namespace llvm {
/// This is a simple memory manager which implements the methods called by
/// the RuntimeDyld class to allocate memory for section-based loading of
/// objects, usually those generated by the MCJIT execution engine.
///
/// This memory manager allocates all section memory as read-write. The
/// RuntimeDyld will copy JITed section memory into these allocated blocks
/// and perform any necessary linking and relocations.
///
/// Any client using this memory manager MUST ensure that section-specific
/// page permissions have been applied before attempting to execute functions
/// in the JITed object. Permissions can be applied either by calling
/// MCJIT::finalizeObject or by calling SectionMemoryManager::applyPermissions
/// directly. Clients of MCJIT should call MCJIT::finalizeObject.
class SectionMemoryManager : public JITMemoryManager {
SectionMemoryManager(const SectionMemoryManager&) LLVM_DELETED_FUNCTION;
void operator=(const SectionMemoryManager&) LLVM_DELETED_FUNCTION;
public:
SectionMemoryManager() { }
virtual ~SectionMemoryManager();
/// \brief Allocates a memory block of (at least) the given size suitable for
/// executable code.
///
/// The value of \p Alignment must be a power of two. If \p Alignment is zero
/// a default alignment of 16 will be used.
virtual uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment,
unsigned SectionID);
/// \brief Allocates a memory block of (at least) the given size suitable for
/// executable code.
///
/// The value of \p Alignment must be a power of two. If \p Alignment is zero
/// a default alignment of 16 will be used.
virtual uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment,
unsigned SectionID,
bool isReadOnly);
/// \brief Applies section-specific memory permissions.
///
/// This method is called when object loading is complete and section page
/// permissions can be applied. It is up to the memory manager implementation
/// to decide whether or not to act on this method. The memory manager will
/// typically allocate all sections as read-write and then apply specific
/// permissions when this method is called. Code sections cannot be executed
/// until this function has been called.
///
/// \returns true if an error occurred, false otherwise.
virtual bool applyPermissions(std::string *ErrMsg = 0);
void registerEHFrames(StringRef SectionData);
/// This method returns the address of the specified function. As such it is
/// only useful for resolving library symbols, not code generated symbols.
///
/// If \p AbortOnFailure is false and no function with the given name is
/// found, this function returns a null pointer. Otherwise, it prints a
/// message to stderr and aborts.
virtual void *getPointerToNamedFunction(const std::string &Name,
bool AbortOnFailure = true);
/// \brief Invalidate instruction cache for code sections.
///
/// Some platforms with separate data cache and instruction cache require
/// explicit cache flush, otherwise JIT code manipulations (like resolved
/// relocations) will get to the data cache but not to the instruction cache.
///
/// This method is called from applyPermissions.
virtual void invalidateInstructionCache();
private:
struct MemoryGroup {
SmallVector<sys::MemoryBlock, 16> AllocatedMem;
SmallVector<sys::MemoryBlock, 16> FreeMem;
sys::MemoryBlock Near;
};
uint8_t *allocateSection(MemoryGroup &MemGroup, uintptr_t Size,
unsigned Alignment);
error_code applyMemoryGroupPermissions(MemoryGroup &MemGroup,
unsigned Permissions);
MemoryGroup CodeMem;
MemoryGroup RWDataMem;
MemoryGroup RODataMem;
public:
///
/// Functions below are not used by MCJIT or RuntimeDyld, but must be
/// implemented because they are declared as pure virtuals in the base class.
///
virtual void setMemoryWritable() {
llvm_unreachable("Unexpected call!");
}
virtual void setMemoryExecutable() {
llvm_unreachable("Unexpected call!");
}
virtual void setPoisonMemory(bool poison) {
llvm_unreachable("Unexpected call!");
}
virtual void AllocateGOT() {
llvm_unreachable("Unexpected call!");
}
virtual uint8_t *getGOTBase() const {
llvm_unreachable("Unexpected call!");
return 0;
}
virtual uint8_t *startFunctionBody(const Function *F,
uintptr_t &ActualSize){
llvm_unreachable("Unexpected call!");
return 0;
}
virtual uint8_t *allocateStub(const GlobalValue *F, unsigned StubSize,
unsigned Alignment) {
llvm_unreachable("Unexpected call!");
return 0;
}
virtual void endFunctionBody(const Function *F, uint8_t *FunctionStart,
uint8_t *FunctionEnd) {
llvm_unreachable("Unexpected call!");
}
virtual uint8_t *allocateSpace(intptr_t Size, unsigned Alignment) {
llvm_unreachable("Unexpected call!");
return 0;
}
virtual uint8_t *allocateGlobal(uintptr_t Size, unsigned Alignment) {
llvm_unreachable("Unexpected call!");
return 0;
}
virtual void deallocateFunctionBody(void *Body) {
llvm_unreachable("Unexpected call!");
}
};
}
#endif // LLVM_EXECUTION_ENGINE_SECTION_MEMORY_MANAGER_H
|
