Merge pull request #1 from auth12/windows

Windows

1 files changed, 278 insertions, 0 deletions

diff --git a/client/asmjit/core/jitallocator.h b/client/asmjit/core/jitallocator.h
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+++ b/client/asmjit/core/jitallocator.h
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+// AsmJit - Machine code generation for C++
+//
+//  * Official AsmJit Home Page: https://asmjit.com
+//  * Official Github Repository: https://github.com/asmjit/asmjit
+//
+// Copyright (c) 2008-2020 The AsmJit Authors
+//
+// This software is provided 'as-is', without any express or implied
+// warranty. In no event will the authors be held liable for any damages
+// arising from the use of this software.
+//
+// Permission is granted to anyone to use this software for any purpose,
+// including commercial applications, and to alter it and redistribute it
+// freely, subject to the following restrictions:
+//
+// 1. The origin of this software must not be misrepresented; you must not
+//    claim that you wrote the original software. If you use this software
+//    in a product, an acknowledgment in the product documentation would be
+//    appreciated but is not required.
+// 2. Altered source versions must be plainly marked as such, and must not be
+//    misrepresented as being the original software.
+// 3. This notice may not be removed or altered from any source distribution.
+
+#ifndef ASMJIT_CORE_JITALLOCATOR_H_INCLUDED
+#define ASMJIT_CORE_JITALLOCATOR_H_INCLUDED
+
+#include "../core/api-config.h"
+#ifndef ASMJIT_NO_JIT
+
+#include "../core/globals.h"
+#include "../core/virtmem.h"
+
+ASMJIT_BEGIN_NAMESPACE
+
+//! \addtogroup asmjit_virtual_memory
+//! \{
+
+// ============================================================================
+// [asmjit::JitAllocator]
+// ============================================================================
+
+//! A simple implementation of memory manager that uses `asmjit::VirtMem`
+//! functions to manage virtual memory for JIT compiled code.
+//!
+//! Implementation notes:
+//!
+//! - Granularity of allocated blocks is different than granularity for a typical
+//!   C malloc. In addition, the allocator can use several memory pools having a
+//!   different granularity to minimize the maintenance overhead. Multiple pools
+//!   feature requires `kFlagUseMultiplePools` flag to be set.
+//!
+//! - The allocator doesn't store any information in executable memory, instead,
+//!   the implementation uses two bit-vectors to manage allocated memory of each
+//!   allocator-block. The first bit-vector called 'used' is used to track used
+//!   memory (where each bit represents memory size defined by granularity) and
+//!   the second bit vector called 'stop' is used as a sentinel to mark where
+//!   the allocated area ends.
+//!
+//! - Internally, the allocator also uses RB tree to keep track of all blocks
+//!   across all pools. Each inserted block is added to the tree so it can be
+//!   matched fast during `release()` and `shrink()`.
+class JitAllocator {
+public:
+  ASMJIT_NONCOPYABLE(JitAllocator)
+
+  struct Impl {
+    //! Allocator options, see \ref JitAllocator::Options.
+    uint32_t options;
+    //! Base block size (0 if the allocator is not initialized).
+    uint32_t blockSize;
+    //! Base granularity (0 if the allocator is not initialized).
+    uint32_t granularity;
+    //! A pattern that is used to fill unused memory if secure mode is enabled.
+    uint32_t fillPattern;
+  };
+
+  //! Allocator implementation (private).
+  Impl* _impl;
+
+  enum Options : uint32_t {
+    //! Enables the use of an anonymous memory-mapped memory that is mapped into
+    //! two buffers having a different pointer. The first buffer has read and
+    //! execute permissions and the second buffer has read+write permissions.
+    //!
+    //! See \ref VirtMem::allocDualMapping() for more details about this feature.
+    kOptionUseDualMapping = 0x00000001u,
+
+    //! Enables the use of multiple pools with increasing granularity instead of
+    //! a single pool. This flag would enable 3 internal pools in total having
+    //! 64, 128, and 256 bytes granularity.
+    //!
+    //! This feature is only recommended for users that generate a lot of code
+    //! and would like to minimize the overhead of `JitAllocator` itself by
+    //! having blocks of different allocation granularities. Using this feature
+    //! only for few allocations won't pay off as the allocator may need to
+    //! create more blocks initially before it can take the advantage of
+    //! variable block granularity.
+    kOptionUseMultiplePools = 0x00000002u,
+
+    //! Always fill reserved memory by a fill-pattern.
+    //!
+    //! Causes a new block to be cleared by the fill pattern and freshly
+    //! released memory to be cleared before making it ready for another use.
+    kOptionFillUnusedMemory = 0x00000004u,
+
+    //! When this flag is set the allocator would immediately release unused
+    //! blocks during `release()` or `reset()`. When this flag is not set the
+    //! allocator would keep one empty block in each pool to prevent excessive
+    //! virtual memory allocations and deallocations in border cases, which
+    //! involve constantly allocating and deallocating a single block caused
+    //! by repetitive calling `alloc()` and `release()` when the allocator has
+    //! either no blocks or have all blocks fully occupied.
+    kOptionImmediateRelease = 0x00000008u,
+
+    //! Use a custom fill pattern, must be combined with `kFlagFillUnusedMemory`.
+    kOptionCustomFillPattern = 0x10000000u
+  };
+
+  //! \name Construction & Destruction
+  //! \{
+
+  //! Parameters that can be passed to `JitAllocator` constructor.
+  //!
+  //! Use it like this:
+  //!
+  //! ```
+  //! // Zero initialize (zero means the default value) and change what you need.
+  //! JitAllocator::CreateParams params {};
+  //! params.blockSize = 1024 * 1024;
+  //!
+  //! // Create the allocator.
+  //! JitAllocator allocator(&params);
+  //! ```
+  struct CreateParams {
+    //! Allocator options, see \ref JitAllocator::Options.
+    //!
+    //! No options are used by default.
+    uint32_t options;
+
+    //! Base size of a single block in bytes (default 64kB).
+    //!
+    //! \remarks Block size must be equal or greater to page size and must be
+    //! power of 2. If the input is not valid then the default block size will
+    //! be used instead.
+    uint32_t blockSize;
+
+    //! Base granularity (and also natural alignment) of allocations in bytes
+    //! (default 64).
+    //!
+    //! Since the `JitAllocator` uses bit-arrays to mark used memory the
+    //! granularity also specifies how many bytes correspond to a single bit in
+    //! such bit-array. Higher granularity means more waste of virtual memory
+    //! (as it increases the natural alignment), but smaller bit-arrays as less
+    //! bits would be required per a single block.
+    uint32_t granularity;
+
+    //! Patter to use to fill unused memory.
+    //!
+    //! Only used if \ref kOptionCustomFillPattern is set.
+    uint32_t fillPattern;
+
+    // Reset the content of `CreateParams`.
+    inline void reset() noexcept { memset(this, 0, sizeof(*this)); }
+  };
+
+  //! Creates a `JitAllocator` instance.
+  explicit ASMJIT_API JitAllocator(const CreateParams* params = nullptr) noexcept;
+  //! Destroys the `JitAllocator` instance and release all blocks held.
+  ASMJIT_API ~JitAllocator() noexcept;
+
+  inline bool isInitialized() const noexcept { return _impl->blockSize == 0; }
+
+  //! Free all allocated memory - makes all pointers returned by `alloc()` invalid.
+  //!
+  //! \remarks This function is not thread-safe as it's designed to be used when
+  //! nobody else is using allocator. The reason is that there is no point of
+  //1 calling `reset()` when the allocator is still in use.
+  ASMJIT_API void reset(uint32_t resetPolicy = Globals::kResetSoft) noexcept;
+
+  //! \}
+
+  //! \name Accessors
+  //! \{
+
+  //! Returns allocator options, see `Flags`.
+  inline uint32_t options() const noexcept { return _impl->options; }
+  //! Tests whether the allocator has the given `option` set.
+  inline bool hasOption(uint32_t option) const noexcept { return (_impl->options & option) != 0; }
+
+  //! Returns a base block size (a minimum size of block that the allocator would allocate).
+  inline uint32_t blockSize() const noexcept { return _impl->blockSize; }
+  //! Returns granularity of the allocator.
+  inline uint32_t granularity() const noexcept { return _impl->granularity; }
+  //! Returns pattern that is used to fill unused memory if `kFlagUseFillPattern` is set.
+  inline uint32_t fillPattern() const noexcept { return _impl->fillPattern; }
+
+  //! \}
+
+  //! \name Alloc & Release
+  //! \{
+
+  //! Allocate `size` bytes of virtual memory.
+  //!
+  //! \remarks This function is thread-safe.
+  ASMJIT_API Error alloc(void** roPtrOut, void** rwPtrOut, size_t size) noexcept;
+
+  //! Release a memory returned by `alloc()`.
+  //!
+  //! \remarks This function is thread-safe.
+  ASMJIT_API Error release(void* ro) noexcept;
+
+  //! Free extra memory allocated with `p` by restricting it to `newSize` size.
+  //!
+  //! \remarks This function is thread-safe.
+  ASMJIT_API Error shrink(void* ro, size_t newSize) noexcept;
+
+  //! \}
+
+  //! \name Statistics
+  //! \{
+
+  //! Statistics about `JitAllocator`.
+  struct Statistics {
+    //! Number of blocks `JitAllocator` maintains.
+    size_t _blockCount;
+    //! How many bytes are currently used / allocated.
+    size_t _usedSize;
+    //! How many bytes are currently reserved by the allocator.
+    size_t _reservedSize;
+    //! Allocation overhead (in bytes) required to maintain all blocks.
+    size_t _overheadSize;
+
+    inline void reset() noexcept {
+      _blockCount = 0;
+      _usedSize = 0;
+      _reservedSize = 0;
+      _overheadSize = 0;
+    }
+
+    //! Returns count of blocks managed by `JitAllocator` at the moment.
+    inline size_t blockCount() const noexcept { return _blockCount; }
+
+    //! Returns how many bytes are currently used.
+    inline size_t usedSize() const noexcept { return _usedSize; }
+    //! Returns the number of bytes unused by the allocator at the moment.
+    inline size_t unusedSize() const noexcept { return _reservedSize - _usedSize; }
+    //! Returns the total number of bytes bytes reserved by the allocator (sum of sizes of all blocks).
+    inline size_t reservedSize() const noexcept { return _reservedSize; }
+    //! Returns the number of bytes the allocator needs to manage the allocated memory.
+    inline size_t overheadSize() const noexcept { return _overheadSize; }
+
+    inline double usedSizeAsPercent() const noexcept {
+      return (double(usedSize()) / (double(reservedSize()) + 1e-16)) * 100.0;
+    }
+
+    inline double unusedSizeAsPercent() const noexcept {
+      return (double(unusedSize()) / (double(reservedSize()) + 1e-16)) * 100.0;
+    }
+
+    inline double overheadSizeAsPercent() const noexcept {
+      return (double(overheadSize()) / (double(reservedSize()) + 1e-16)) * 100.0;
+    }
+  };
+
+  //! Returns JIT allocator statistics.
+  //!
+  //! \remarks This function is thread-safe.
+  ASMJIT_API Statistics statistics() const noexcept;
+
+  //! \}
+};
+
+//! \}
+
+ASMJIT_END_NAMESPACE
+
+#endif
+#endif