1 //===- SectionMemoryManager.h - Memory manager for MCJIT/RtDyld -*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file contains the declaration of a section-based memory manager used by 11 // the MCJIT execution engine and RuntimeDyld. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_EXECUTIONENGINE_SECTIONMEMORYMANAGER_H 16 #define LLVM_EXECUTIONENGINE_SECTIONMEMORYMANAGER_H 17 18 #include "llvm/ADT/SmallVector.h" 19 #include "llvm/ExecutionEngine/RuntimeDyld.h" 20 #include "llvm/Support/ErrorHandling.h" 21 #include "llvm/Support/Memory.h" 22 23 namespace llvm { 24 25 /// This is a simple memory manager which implements the methods called by 26 /// the RuntimeDyld class to allocate memory for section-based loading of 27 /// objects, usually those generated by the MCJIT execution engine. 28 /// 29 /// This memory manager allocates all section memory as read-write. The 30 /// RuntimeDyld will copy JITed section memory into these allocated blocks 31 /// and perform any necessary linking and relocations. 32 /// 33 /// Any client using this memory manager MUST ensure that section-specific 34 /// page permissions have been applied before attempting to execute functions 35 /// in the JITed object. Permissions can be applied either by calling 36 /// MCJIT::finalizeObject or by calling SectionMemoryManager::finalizeMemory 37 /// directly. Clients of MCJIT should call MCJIT::finalizeObject. 38 class SectionMemoryManager : public RTDyldMemoryManager { 39 SectionMemoryManager(const SectionMemoryManager&) LLVM_DELETED_FUNCTION; 40 void operator=(const SectionMemoryManager&) LLVM_DELETED_FUNCTION; 41 42 public: 43 SectionMemoryManager() { } 44 virtual ~SectionMemoryManager(); 45 46 /// \brief Allocates a memory block of (at least) the given size suitable for 47 /// executable code. 48 /// 49 /// The value of \p Alignment must be a power of two. If \p Alignment is zero 50 /// a default alignment of 16 will be used. 51 virtual uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment, 52 unsigned SectionID); 53 54 /// \brief Allocates a memory block of (at least) the given size suitable for 55 /// executable code. 56 /// 57 /// The value of \p Alignment must be a power of two. If \p Alignment is zero 58 /// a default alignment of 16 will be used. 59 virtual uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment, 60 unsigned SectionID, 61 bool isReadOnly); 62 63 /// \brief Update section-specific memory permissions and other attributes. 64 /// 65 /// This method is called when object loading is complete and section page 66 /// permissions can be applied. It is up to the memory manager implementation 67 /// to decide whether or not to act on this method. The memory manager will 68 /// typically allocate all sections as read-write and then apply specific 69 /// permissions when this method is called. Code sections cannot be executed 70 /// until this function has been called. In addition, any cache coherency 71 /// operations needed to reliably use the memory are also performed. 72 /// 73 /// \returns true if an error occurred, false otherwise. 74 virtual bool finalizeMemory(std::string *ErrMsg = 0); 75 76 /// \brief Invalidate instruction cache for code sections. 77 /// 78 /// Some platforms with separate data cache and instruction cache require 79 /// explicit cache flush, otherwise JIT code manipulations (like resolved 80 /// relocations) will get to the data cache but not to the instruction cache. 81 /// 82 /// This method is called from finalizeMemory. 83 virtual void invalidateInstructionCache(); 84 85 private: 86 struct MemoryGroup { 87 SmallVector<sys::MemoryBlock, 16> AllocatedMem; 88 SmallVector<sys::MemoryBlock, 16> FreeMem; 89 sys::MemoryBlock Near; 90 }; 91 92 uint8_t *allocateSection(MemoryGroup &MemGroup, uintptr_t Size, 93 unsigned Alignment); 94 95 error_code applyMemoryGroupPermissions(MemoryGroup &MemGroup, 96 unsigned Permissions); 97 98 MemoryGroup CodeMem; 99 MemoryGroup RWDataMem; 100 MemoryGroup RODataMem; 101 }; 102 103 } 104 105 #endif // LLVM_EXECUTION_ENGINE_SECTION_MEMORY_MANAGER_H 106 107
