sysio::vm::growable_allocator Class Reference

#include <allocator.hpp>

Collaboration diagram for sysio::vm::growable_allocator:

Public Member Functions
	growable_allocator (size_t size)
	~growable_allocator ()
template<typename T >
T *	alloc (size_t size=0)
void *	start_code ()
template<bool IsJit>
void	end_code (void *code_base)
void	enable_code (bool is_jit)
void	disable_code ()
const void *	get_code_start () const
template<typename T >
void	reclaim (const T *ptr, size_t size=0)
void	finalize ()
void	free ()
void	reset ()
	growable_allocator (size_t size)
	~growable_allocator ()
template<typename T >
T *	alloc (size_t size=0)
void *	start_code ()
template<bool IsJit>
void	end_code (void *code_base)
void	enable_code (bool is_jit)
void	disable_code ()
const void *	get_code_start () const
template<typename T >
void	reclaim (const T *ptr, size_t size=0)
void	finalize ()
void	free ()
void	reset ()

Static Public Member Functions
template<std::size_t align_amt>
static constexpr size_t	align_offset (size_t offset)
static std::size_t	align_to_page (std::size_t offset)
template<std::size_t align_amt>
static constexpr size_t	align_offset (size_t offset)
static std::size_t	align_to_page (std::size_t offset)

Public Attributes
size_t	_offset = 0
size_t	_size = 0
std::size_t	_capacity = 0
char *	_base
char *	_code_base = nullptr
size_t	_code_size = 0
bool	is_jit = false

Static Public Attributes
static constexpr size_t	max_memory_size = 1024 * 1024 * 1024
static constexpr size_t	chunk_size = 128 * 1024

Detailed Description

Definition at line 267 of file allocator.hpp.

Constructor & Destructor Documentation

growable_allocator() [1/2]

sysio::vm::growable_allocator::growable_allocator ( size_t size )

inline

Definition at line 281 of file allocator.hpp.

                                      {
         SYS_VM_ASSERT(size <= max_memory_size, wasm_bad_alloc, "Too large initial memory size");
         _base = (char*)mmap(NULL, max_memory_size, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
         SYS_VM_ASSERT(_base != MAP_FAILED, wasm_bad_alloc, "mmap failed.");
         if (size != 0) {
            size_t chunks_to_alloc = (align_offset<chunk_size>(size) / chunk_size);
            _size += (chunk_size * chunks_to_alloc);
            mprotect((char*)_base, _size, PROT_READ | PROT_WRITE);
         }
         _capacity = max_memory_size;
      }

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~growable_allocator() [1/2]

sysio::vm::growable_allocator::~growable_allocator ( )

inline

Definition at line 293 of file allocator.hpp.

                            {
         munmap(_base, _capacity);
         if (is_jit) {
            jit_allocator::instance().free(_code_base);
         }
      }

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growable_allocator() [2/2]

sysio::vm::growable_allocator::growable_allocator ( size_t size )

inline

Definition at line 281 of file allocator.hpp.

                                      {
         SYS_VM_ASSERT(size <= max_memory_size, wasm_bad_alloc, "Too large initial memory size");
         _base = (char*)mmap(NULL, max_memory_size, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
         SYS_VM_ASSERT(_base != MAP_FAILED, wasm_bad_alloc, "mmap failed.");
         if (size != 0) {
            size_t chunks_to_alloc = (align_offset<chunk_size>(size) / chunk_size);
            _size += (chunk_size * chunks_to_alloc);
            mprotect((char*)_base, _size, PROT_READ | PROT_WRITE);
         }
         _capacity = max_memory_size;
      }

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~growable_allocator() [2/2]

sysio::vm::growable_allocator::~growable_allocator ( )

inline

Definition at line 293 of file allocator.hpp.

                            {
         munmap(_base, _capacity);
         if (is_jit) {
            jit_allocator::instance().free(_code_base);
         }
      }

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Member Function Documentation

align_offset() [1/2]

template<std::size_t align_amt>

static constexpr size_t sysio::vm::growable_allocator::align_offset ( size_t offset )

inlinestaticconstexpr

Definition at line 272 of file allocator.hpp.

{ return (offset + align_amt - 1) & ~(align_amt - 1); }

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align_offset() [2/2]

template<std::size_t align_amt>

static constexpr size_t sysio::vm::growable_allocator::align_offset ( size_t offset )

inlinestaticconstexpr

Definition at line 272 of file allocator.hpp.

{ return (offset + align_amt - 1) & ~(align_amt - 1); }

align_to_page() [1/2]

static std::size_t sysio::vm::growable_allocator::align_to_page ( std::size_t offset )

inlinestatic

Definition at line 274 of file allocator.hpp.

                                                       {
         std::size_t pagesize = static_cast<std::size_t>(::sysconf(_SC_PAGESIZE));
         assert(max_memory_size % page_size == 0);
         return (offset + pagesize - 1) & ~(pagesize - 1);
      }

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align_to_page() [2/2]

static std::size_t sysio::vm::growable_allocator::align_to_page ( std::size_t offset )

inlinestatic

Definition at line 274 of file allocator.hpp.

                                                       {
         std::size_t pagesize = static_cast<std::size_t>(::sysconf(_SC_PAGESIZE));
         assert(max_memory_size % page_size == 0);
         return (offset + pagesize - 1) & ~(pagesize - 1);
      }

alloc() [1/2]

template<typename T >

T * sysio::vm::growable_allocator::alloc ( size_t size = 0 )

inline

Definition at line 302 of file allocator.hpp.

                                {
         static_assert(max_memory_size % alignof(T) == 0, "alignment must divide max_memory_size.");
         _offset = align_offset<alignof(T)>(_offset);
         // Evaluating the inequality in this form cannot cause integer overflow.
         // Once this assertion passes, the rest of the function is safe.
         SYS_VM_ASSERT ((max_memory_size - _offset) / sizeof(T) >= size, wasm_bad_alloc, "Allocated too much memory");
         size_t aligned = (sizeof(T) * size) + _offset;
         if (aligned > _size) {
            size_t chunks_to_alloc = align_offset<chunk_size>(aligned - _size) / chunk_size;
            mprotect((char*)_base + _size, (chunk_size * chunks_to_alloc), PROT_READ | PROT_WRITE);
            _size += (chunk_size * chunks_to_alloc);
         }
 
         T* ptr  = (T*)(_base + _offset);
         _offset = aligned;
         return ptr;
      }

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alloc() [2/2]

template<typename T >

T * sysio::vm::growable_allocator::alloc ( size_t size = 0 )

inline

Definition at line 302 of file allocator.hpp.

                                {
         static_assert(max_memory_size % alignof(T) == 0, "alignment must divide max_memory_size.");
         _offset = align_offset<alignof(T)>(_offset);
         // Evaluating the inequality in this form cannot cause integer overflow.
         // Once this assertion passes, the rest of the function is safe.
         SYS_VM_ASSERT ((max_memory_size - _offset) / sizeof(T) >= size, wasm_bad_alloc, "Allocated too much memory");
         size_t aligned = (sizeof(T) * size) + _offset;
         if (aligned > _size) {
            size_t chunks_to_alloc = align_offset<chunk_size>(aligned - _size) / chunk_size;
            mprotect((char*)_base + _size, (chunk_size * chunks_to_alloc), PROT_READ | PROT_WRITE);
            _size += (chunk_size * chunks_to_alloc);
         }
 
         T* ptr  = (T*)(_base + _offset);
         _offset = aligned;
         return ptr;
      }

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disable_code() [1/2]

void sysio::vm::growable_allocator::disable_code ( )

inline

Definition at line 349 of file allocator.hpp.

                          {
         mprotect(_code_base, _code_size, PROT_NONE);
      }

disable_code() [2/2]

void sysio::vm::growable_allocator::disable_code ( )

inline

Definition at line 349 of file allocator.hpp.

                          {
         mprotect(_code_base, _code_size, PROT_NONE);
      }

enable_code() [1/2]

void sysio::vm::growable_allocator::enable_code ( bool is_jit )

inline

Definition at line 345 of file allocator.hpp.

                                    {
         mprotect(_code_base, _code_size, is_jit?PROT_EXEC:(PROT_READ|PROT_WRITE));
      }

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enable_code() [2/2]

void sysio::vm::growable_allocator::enable_code ( bool is_jit )

inline

Definition at line 345 of file allocator.hpp.

                                    {
         mprotect(_code_base, _code_size, is_jit?PROT_EXEC:(PROT_READ|PROT_WRITE));
      }

end_code() [1/2]

template<bool IsJit>

void sysio::vm::growable_allocator::end_code ( void * code_base )

inline

Definition at line 325 of file allocator.hpp.

                                      {
         assert((char*)code_base >= _base);
         assert((char*)code_base <= (_base+_offset));
         _offset = align_to_page(_offset);
         _code_base = (char*)code_base;
         _code_size = _offset - ((char*)code_base - _base);
         if constexpr (IsJit) {
            auto & jit_alloc = jit_allocator::instance();
            void * executable_code = jit_alloc.alloc(_code_size);
            int err = mprotect(executable_code, _code_size, PROT_READ | PROT_WRITE);
            SYS_VM_ASSERT(err == 0, wasm_bad_alloc, "mprotect failed");
            std::memcpy(executable_code, _code_base, _code_size);
            is_jit = true;
            _code_base = (char*)executable_code;
            _offset = (char*)code_base - _base;
         }
         enable_code(IsJit);
      }

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end_code() [2/2]

template<bool IsJit>

void sysio::vm::growable_allocator::end_code ( void * code_base )

inline

Definition at line 325 of file allocator.hpp.

                                      {
         assert((char*)code_base >= _base);
         assert((char*)code_base <= (_base+_offset));
         _offset = align_to_page(_offset);
         _code_base = (char*)code_base;
         _code_size = _offset - ((char*)code_base - _base);
         if constexpr (IsJit) {
            auto & jit_alloc = jit_allocator::instance();
            void * executable_code = jit_alloc.alloc(_code_size);
            int err = mprotect(executable_code, _code_size, PROT_READ | PROT_WRITE);
            SYS_VM_ASSERT(err == 0, wasm_bad_alloc, "mprotect failed");
            std::memcpy(executable_code, _code_base, _code_size);
            is_jit = true;
            _code_base = (char*)executable_code;
            _offset = (char*)code_base - _base;
         }
         enable_code(IsJit);
      }

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finalize() [1/2]

void sysio::vm::growable_allocator::finalize ( )

inline

Definition at line 369 of file allocator.hpp.

                      {
         if(_capacity != _offset) {
            std::size_t final_size = align_to_page(_offset);
            SYS_VM_ASSERT(munmap(_base + final_size, _capacity - final_size) == 0, wasm_bad_alloc, "failed to finalize growable_allocator");
            _capacity = _size = _offset = final_size;
         }
      }

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finalize() [2/2]

void sysio::vm::growable_allocator::finalize ( )

inline

Definition at line 369 of file allocator.hpp.

                      {
         if(_capacity != _offset) {
            std::size_t final_size = align_to_page(_offset);
            SYS_VM_ASSERT(munmap(_base + final_size, _capacity - final_size) == 0, wasm_bad_alloc, "failed to finalize growable_allocator");
            _capacity = _size = _offset = final_size;
         }
      }

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free() [1/2]

void sysio::vm::growable_allocator::free ( )

inline

Definition at line 377 of file allocator.hpp.

{ SYS_VM_ASSERT(false, wasm_bad_alloc, "unimplemented"); }

free() [2/2]

void sysio::vm::growable_allocator::free ( )

inline

Definition at line 377 of file allocator.hpp.

{ SYS_VM_ASSERT(false, wasm_bad_alloc, "unimplemented"); }

get_code_start() [1/2]

const void * sysio::vm::growable_allocator::get_code_start ( ) const

inline

Definition at line 353 of file allocator.hpp.

{ return _code_base; }

get_code_start() [2/2]

const void * sysio::vm::growable_allocator::get_code_start ( ) const

inline

Definition at line 353 of file allocator.hpp.

{ return _code_base; }

reclaim() [1/2]

template<typename T >

void sysio::vm::growable_allocator::reclaim ( const T * ptr, size_t size = 0 )

inline

Definition at line 359 of file allocator.hpp.

                                                {
         SYS_VM_ASSERT( _offset / sizeof(T) >= size, wasm_bad_alloc, "reclaimed too much memory" );
         SYS_VM_ASSERT( size == 0 || (char*)(ptr + size) == (_base + _offset), wasm_bad_alloc, "reclaiming memory must be strictly LIFO");
         if ( size != 0 )
            _offset = ((char*)ptr - _base);
      }

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reclaim() [2/2]

template<typename T >

void sysio::vm::growable_allocator::reclaim ( const T * ptr, size_t size = 0 )

inline

Definition at line 359 of file allocator.hpp.

                                                {
         SYS_VM_ASSERT( _offset / sizeof(T) >= size, wasm_bad_alloc, "reclaimed too much memory" );
         SYS_VM_ASSERT( size == 0 || (char*)(ptr + size) == (_base + _offset), wasm_bad_alloc, "reclaiming memory must be strictly LIFO");
         if ( size != 0 )
            _offset = ((char*)ptr - _base);
      }

reset() [1/2]

void sysio::vm::growable_allocator::reset ( )

inline

Definition at line 379 of file allocator.hpp.

{ _offset = 0; }

reset() [2/2]

void sysio::vm::growable_allocator::reset ( )

inline

Definition at line 379 of file allocator.hpp.

{ _offset = 0; }

start_code() [1/2]

void * sysio::vm::growable_allocator::start_code ( )

inline

Definition at line 320 of file allocator.hpp.

                          {
         _offset = align_to_page(_offset);
         return _base + _offset;
      }

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start_code() [2/2]

void * sysio::vm::growable_allocator::start_code ( )

inline

Definition at line 320 of file allocator.hpp.

                          {
         _offset = align_to_page(_offset);
         return _base + _offset;
      }

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Member Data Documentation

_base

char * sysio::vm::growable_allocator::_base

Definition at line 384 of file allocator.hpp.

_capacity

std::size_t sysio::vm::growable_allocator::_capacity = 0

Definition at line 383 of file allocator.hpp.

_code_base

char * sysio::vm::growable_allocator::_code_base = nullptr

Definition at line 385 of file allocator.hpp.

_code_size

size_t sysio::vm::growable_allocator::_code_size = 0

Definition at line 386 of file allocator.hpp.

_offset

size_t sysio::vm::growable_allocator::_offset = 0

Definition at line 381 of file allocator.hpp.

_size

size_t sysio::vm::growable_allocator::_size = 0

Definition at line 382 of file allocator.hpp.

chunk_size

static constexpr size_t sysio::vm::growable_allocator::chunk_size = 128 * 1024

staticconstexpr

Definition at line 270 of file allocator.hpp.

is_jit

bool sysio::vm::growable_allocator::is_jit = false

Definition at line 387 of file allocator.hpp.

max_memory_size

static constexpr size_t sysio::vm::growable_allocator::max_memory_size = 1024 * 1024 * 1024

staticconstexpr

Definition at line 269 of file allocator.hpp.

---

The documentation for this class was generated from the following files:

• libraries/sys-vm/include/sysio/sysio/vm/allocator.hpp
• libraries/sys-vm/include/sysio/vm/allocator.hpp