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Diffstat (limited to 'src/include/jit/SectionMemoryManager.h')
| -rw-r--r-- | src/include/jit/SectionMemoryManager.h | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/src/include/jit/SectionMemoryManager.h b/src/include/jit/SectionMemoryManager.h new file mode 100644 index 00000000000..93cf9771570 --- /dev/null +++ b/src/include/jit/SectionMemoryManager.h @@ -0,0 +1,226 @@ +/* + * This is a copy LLVM source code modified by the PostgreSQL project. + * See SectionMemoryManager.cpp for notes on provenance and license. + */ + +//===- SectionMemoryManager.h - Memory manager for MCJIT/RtDyld -*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file contains the declaration of a section-based memory manager used by +// the MCJIT execution engine and RuntimeDyld. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_EXECUTIONENGINE_BACKPORT_SECTIONMEMORYMANAGER_H +#define LLVM_EXECUTIONENGINE_BACKPORT_SECTIONMEMORYMANAGER_H + +#include "llvm/ADT/SmallVector.h" +#include "llvm/ExecutionEngine/RTDyldMemoryManager.h" +#include "llvm/Support/Alignment.h" +#include "llvm/Support/Memory.h" +#include <cstdint> +#include <string> +#include <system_error> + +namespace llvm { +namespace backport { + +/// 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 { +public: + /// This enum describes the various reasons to allocate pages from + /// allocateMappedMemory. + enum class AllocationPurpose { + Code, + ROData, + RWData, + }; + + /// Implementations of this interface are used by SectionMemoryManager to + /// request pages from the operating system. + class MemoryMapper { + public: + /// This method attempts to allocate \p NumBytes bytes of virtual memory for + /// \p Purpose. \p NearBlock may point to an existing allocation, in which + /// case an attempt is made to allocate more memory near the existing block. + /// The actual allocated address is not guaranteed to be near the requested + /// address. \p Flags is used to set the initial protection flags for the + /// block of the memory. \p EC [out] returns an object describing any error + /// that occurs. + /// + /// This method may allocate more than the number of bytes requested. The + /// actual number of bytes allocated is indicated in the returned + /// MemoryBlock. + /// + /// The start of the allocated block must be aligned with the system + /// allocation granularity (64K on Windows, page size on Linux). If the + /// address following \p NearBlock is not so aligned, it will be rounded up + /// to the next allocation granularity boundary. + /// + /// \r a non-null MemoryBlock if the function was successful, otherwise a + /// null MemoryBlock with \p EC describing the error. + virtual sys::MemoryBlock + allocateMappedMemory(AllocationPurpose Purpose, size_t NumBytes, + const sys::MemoryBlock *const NearBlock, + unsigned Flags, std::error_code &EC) = 0; + + /// This method sets the protection flags for a block of memory to the state + /// specified by \p Flags. The behavior is not specified if the memory was + /// not allocated using the allocateMappedMemory method. + /// \p Block describes the memory block to be protected. + /// \p Flags specifies the new protection state to be assigned to the block. + /// + /// If \p Flags is MF_WRITE, the actual behavior varies with the operating + /// system (i.e. MF_READ | MF_WRITE on Windows) and the target architecture + /// (i.e. MF_WRITE -> MF_READ | MF_WRITE on i386). + /// + /// \r error_success if the function was successful, or an error_code + /// describing the failure if an error occurred. + virtual std::error_code protectMappedMemory(const sys::MemoryBlock &Block, + unsigned Flags) = 0; + + /// This method releases a block of memory that was allocated with the + /// allocateMappedMemory method. It should not be used to release any memory + /// block allocated any other way. + /// \p Block describes the memory to be released. + /// + /// \r error_success if the function was successful, or an error_code + /// describing the failure if an error occurred. + virtual std::error_code releaseMappedMemory(sys::MemoryBlock &M) = 0; + + virtual ~MemoryMapper(); + }; + + /// Creates a SectionMemoryManager instance with \p MM as the associated + /// memory mapper. If \p MM is nullptr then a default memory mapper is used + /// that directly calls into the operating system. + /// + /// If \p ReserveAlloc is true all memory will be pre-allocated, and any + /// attempts to allocate beyond pre-allocated memory will fail. + SectionMemoryManager(MemoryMapper *MM = nullptr, bool ReserveAlloc = false); + SectionMemoryManager(const SectionMemoryManager &) = delete; + void operator=(const SectionMemoryManager &) = delete; + ~SectionMemoryManager() override; + + /// Enable reserveAllocationSpace when requested. + bool needsToReserveAllocationSpace() override { return ReserveAllocation; } + + /// Implements allocating all memory in a single block. This is required to + /// limit memory offsets to fit the ARM ABI; large memory systems may + /// otherwise allocate separate sections too far apart. +#if LLVM_VERSION_MAJOR < 16 + virtual void reserveAllocationSpace(uintptr_t CodeSize, uint32_t CodeAlign, + uintptr_t RODataSize, + uint32_t RODataAlign, + uintptr_t RWDataSize, + uint32_t RWDataAlign) override; +#else + void reserveAllocationSpace(uintptr_t CodeSize, Align CodeAlign, + uintptr_t RODataSize, Align RODataAlign, + uintptr_t RWDataSize, Align RWDataAlign) override; +#endif + + /// 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. + uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment, + unsigned SectionID, + StringRef SectionName) override; + + /// 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. + uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment, + unsigned SectionID, StringRef SectionName, + bool isReadOnly) override; + + /// 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. + bool finalizeMemory(std::string *ErrMsg = nullptr) override; + + /// 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 FreeMemBlock { + // The actual block of free memory + sys::MemoryBlock Free; + // If there is a pending allocation from the same reservation right before + // this block, store it's index in PendingMem, to be able to update the + // pending region if part of this block is allocated, rather than having to + // create a new one + unsigned PendingPrefixIndex; + }; + + struct MemoryGroup { + // PendingMem contains all blocks of memory (subblocks of AllocatedMem) + // which have not yet had their permissions applied, but have been given + // out to the user. FreeMem contains all block of memory, which have + // neither had their permissions applied, nor been given out to the user. + SmallVector<sys::MemoryBlock, 16> PendingMem; + SmallVector<FreeMemBlock, 16> FreeMem; + + // All memory blocks that have been requested from the system + SmallVector<sys::MemoryBlock, 16> AllocatedMem; + + sys::MemoryBlock Near; + }; + + uint8_t *allocateSection(AllocationPurpose Purpose, uintptr_t Size, + unsigned Alignment); + + std::error_code applyMemoryGroupPermissions(MemoryGroup &MemGroup, + unsigned Permissions); + + bool hasSpace(const MemoryGroup &MemGroup, uintptr_t Size) const; + + void anchor() override; + + MemoryGroup CodeMem; + MemoryGroup RWDataMem; + MemoryGroup RODataMem; + MemoryMapper *MMapper; + std::unique_ptr<MemoryMapper> OwnedMMapper; + bool ReserveAllocation; +}; + +} // end namespace backport +} // end namespace llvm + +#endif // LLVM_EXECUTIONENGINE_BACKPORT_SECTIONMEMORYMANAGER_H |