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llvm-mirror/include/llvm/ExecutionEngine/SectionMemoryManager.h
Filip Pizlo 1e0fa7cd7d This threads SectionName through the allocateCodeSection/allocateDataSection APIs, both in C++ and C land.
It's useful for the memory managers that are allocating a section to know what the name of the section is.  
At a minimum, this is useful for low-level debugging - it's customary for JITs to be able to tell you what 
memory they allocated, and as part of any such dump, they should be able to tell you some meta-data about 
what each allocation is for.  This allows clients that supply their own memory managers to do this.  
Additionally, we also envision the SectionName being useful for passing meta-data from within LLVM to an LLVM 
client.

This changes both the C and C++ APIs, and all of the clients of those APIs within LLVM.  I'm assuming that 
it's safe to change the C++ API because that API is allowed to change.  I'm assuming that it's safe to change 
the C API because we haven't shipped the API in a release yet (LLVM 3.3 doesn't include the MCJIT memory 
management C API).

llvm-svn: 191804
2013-10-02 00:59:25 +00:00

109 lines
4.4 KiB
C++

//===- 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/RuntimeDyld.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::finalizeMemory
/// directly. Clients of MCJIT should call MCJIT::finalizeObject.
class SectionMemoryManager : public RTDyldMemoryManager {
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,
StringRef SectionName);
/// \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,
StringRef SectionName,
bool isReadOnly);
/// \brief Update section-specific memory permissions and other attributes.
///
/// 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. In addition, any cache coherency
/// operations needed to reliably use the memory are also performed.
///
/// \returns true if an error occurred, false otherwise.
virtual bool finalizeMemory(std::string *ErrMsg = 0);
/// \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 finalizeMemory.
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;
};
}
#endif // LLVM_EXECUTION_ENGINE_SECTION_MEMORY_MANAGER_H