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| Dir : //opt/alt/ruby30/include/ruby/internal/memory.h |
#ifndef RBIMPL_MEMORY_H /*-*-C++-*-vi:se ft=cpp:*/
#define RBIMPL_MEMORY_H
/**
* @file
* @author Ruby developers <ruby-core@ruby-lang.org>
* @copyright This file is a part of the programming language Ruby.
* Permission is hereby granted, to either redistribute and/or
* modify this file, provided that the conditions mentioned in the
* file COPYING are met. Consult the file for details.
* @warning Symbols prefixed with either `RBIMPL` or `rbimpl` are
* implementation details. Don't take them as canon. They could
* rapidly appear then vanish. The name (path) of this header file
* is also an implementation detail. Do not expect it to persist
* at the place it is now. Developers are free to move it anywhere
* anytime at will.
* @note To ruby-core: remember that this header can be possibly
* recursively included from extension libraries written in C++.
* Do not expect for instance `__VA_ARGS__` is always available.
* We assume C99 for ruby itself but we don't assume languages of
* extension libraries. They could be written in C++98.
* @brief Memory management stuff.
*/
#include "ruby/internal/config.h"
#ifdef STDC_HEADERS
# include <stddef.h>
#endif
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#ifdef HAVE_STDINT_H
# include <stdint.h>
#endif
#ifdef HAVE_ALLOCA_H
# include <alloca.h>
#endif
#if defined(_MSC_VER) && defined(_WIN64)
# include <intrin.h>
# pragma intrinsic(_umul128)
#endif
#include "ruby/internal/attr/alloc_size.h"
#include "ruby/internal/attr/const.h"
#include "ruby/internal/attr/constexpr.h"
#include "ruby/internal/attr/noalias.h"
#include "ruby/internal/attr/nonnull.h"
#include "ruby/internal/attr/noreturn.h"
#include "ruby/internal/attr/restrict.h"
#include "ruby/internal/attr/returns_nonnull.h"
#include "ruby/internal/cast.h"
#include "ruby/internal/dllexport.h"
#include "ruby/internal/has/builtin.h"
#include "ruby/internal/stdalign.h"
#include "ruby/internal/stdbool.h"
#include "ruby/internal/xmalloc.h"
#include "ruby/backward/2/limits.h"
#include "ruby/backward/2/long_long.h"
#include "ruby/backward/2/assume.h"
#include "ruby/defines.h"
/* Make alloca work the best possible way. */
#if defined(alloca)
# /* Take that. */
#elif RBIMPL_HAS_BUILTIN(__builtin_alloca)
# define alloca __builtin_alloca
#elif defined(_AIX)
# pragma alloca
#elif defined(__cplusplus)
extern "C" void *alloca(size_t);
#else
extern void *alloca();
#endif
#if defined(HAVE_INT128_T) && SIZEOF_SIZE_T <= 8
# define DSIZE_T uint128_t
#elif SIZEOF_SIZE_T * 2 <= SIZEOF_LONG_LONG
# define DSIZE_T unsigned LONG_LONG
#endif
#ifdef C_ALLOCA
# define RUBY_ALLOCV_LIMIT 0
#else
# define RUBY_ALLOCV_LIMIT 1024
#endif
#ifdef __GNUC__
#define RB_GC_GUARD(v) \
(*__extension__ ({ \
volatile VALUE *rb_gc_guarded_ptr = &(v); \
__asm__("" : : "m"(rb_gc_guarded_ptr)); \
rb_gc_guarded_ptr; \
}))
#elif defined _MSC_VER
#define RB_GC_GUARD(v) (*rb_gc_guarded_ptr(&(v)))
#else
#define HAVE_RB_GC_GUARDED_PTR_VAL 1
#define RB_GC_GUARD(v) (*rb_gc_guarded_ptr_val(&(v),(v)))
#endif
/* Casts needed because void* is NOT compaible with others in C++. */
#define RB_ALLOC_N(type,n) RBIMPL_CAST((type *)ruby_xmalloc2((n), sizeof(type)))
#define RB_ALLOC(type) RBIMPL_CAST((type *)ruby_xmalloc(sizeof(type)))
#define RB_ZALLOC_N(type,n) RBIMPL_CAST((type *)ruby_xcalloc((n), sizeof(type)))
#define RB_ZALLOC(type) (RB_ZALLOC_N(type, 1))
#define RB_REALLOC_N(var,type,n) \
((var) = RBIMPL_CAST((type *)ruby_xrealloc2((void *)(var), (n), sizeof(type))))
#define ALLOCA_N(type,n) \
RBIMPL_CAST((type *)(!(n) ? NULL : alloca(rbimpl_size_mul_or_raise(sizeof(type), (n)))))
/* allocates _n_ bytes temporary buffer and stores VALUE including it
* in _v_. _n_ may be evaluated twice. */
#define RB_ALLOCV(v, n) \
((n) < RUBY_ALLOCV_LIMIT ? \
((v) = 0, !(n) ? NULL : alloca(n)) : \
rb_alloc_tmp_buffer(&(v), (n)))
#define RB_ALLOCV_N(type, v, n) \
RBIMPL_CAST((type *) \
(((size_t)(n) < RUBY_ALLOCV_LIMIT / sizeof(type)) ? \
((v) = 0, !(n) ? NULL : alloca((n) * sizeof(type))) : \
rb_alloc_tmp_buffer2(&(v), (n), sizeof(type))))
#define RB_ALLOCV_END(v) rb_free_tmp_buffer(&(v))
#define MEMZERO(p,type,n) memset((p), 0, rbimpl_size_mul_or_raise(sizeof(type), (n)))
#define MEMCPY(p1,p2,type,n) memcpy((p1), (p2), rbimpl_size_mul_or_raise(sizeof(type), (n)))
#define MEMMOVE(p1,p2,type,n) memmove((p1), (p2), rbimpl_size_mul_or_raise(sizeof(type), (n)))
#define MEMCMP(p1,p2,type,n) memcmp((p1), (p2), rbimpl_size_mul_or_raise(sizeof(type), (n)))
#define ALLOC_N RB_ALLOC_N
#define ALLOC RB_ALLOC
#define ZALLOC_N RB_ZALLOC_N
#define ZALLOC RB_ZALLOC
#define REALLOC_N RB_REALLOC_N
#define ALLOCV RB_ALLOCV
#define ALLOCV_N RB_ALLOCV_N
#define ALLOCV_END RB_ALLOCV_END
/* Expecting this struct to be eliminated by function inlinings */
struct rbimpl_size_mul_overflow_tag {
bool left;
size_t right;
};
RBIMPL_SYMBOL_EXPORT_BEGIN()
RBIMPL_ATTR_RESTRICT()
RBIMPL_ATTR_RETURNS_NONNULL()
RBIMPL_ATTR_ALLOC_SIZE((2))
void *rb_alloc_tmp_buffer(volatile VALUE *store, long len);
RBIMPL_ATTR_RESTRICT()
RBIMPL_ATTR_RETURNS_NONNULL()
RBIMPL_ATTR_ALLOC_SIZE((2,3))
void *rb_alloc_tmp_buffer_with_count(volatile VALUE *store, size_t len,size_t count);
void rb_free_tmp_buffer(volatile VALUE *store);
RBIMPL_ATTR_NORETURN()
void ruby_malloc_size_overflow(size_t, size_t);
#ifdef HAVE_RB_GC_GUARDED_PTR_VAL
volatile VALUE *rb_gc_guarded_ptr_val(volatile VALUE *ptr, VALUE val);
#endif
RBIMPL_SYMBOL_EXPORT_END()
#ifdef _MSC_VER
# pragma optimize("", off)
static inline volatile VALUE *
rb_gc_guarded_ptr(volatile VALUE *ptr)
{
return ptr;
}
# pragma optimize("", on)
#endif
/* Does anyone use it? Just here for backwards compatibility. */
static inline int
rb_mul_size_overflow(size_t a, size_t b, size_t max, size_t *c)
{
#ifdef DSIZE_T
RB_GNUC_EXTENSION DSIZE_T da, db, c2;
da = a;
db = b;
c2 = da * db;
if (c2 > max) return 1;
*c = RBIMPL_CAST((size_t)c2);
#else
if (b != 0 && a > max / b) return 1;
*c = a * b;
#endif
return 0;
}
#if RBIMPL_COMPILER_SINCE(GCC, 7, 0, 0)
RBIMPL_ATTR_CONSTEXPR(CXX14) /* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70507 */
#elif RBIMPL_COMPILER_SINCE(Clang, 7, 0, 0)
RBIMPL_ATTR_CONSTEXPR(CXX14) /* https://bugs.llvm.org/show_bug.cgi?id=37633 */
#endif
RBIMPL_ATTR_CONST()
static inline struct rbimpl_size_mul_overflow_tag
rbimpl_size_mul_overflow(size_t x, size_t y)
{
struct rbimpl_size_mul_overflow_tag ret = { false, 0, };
#if RBIMPL_HAS_BUILTIN(__builtin_mul_overflow)
ret.left = __builtin_mul_overflow(x, y, &ret.right);
#elif defined(DSIZE_T)
RB_GNUC_EXTENSION DSIZE_T dx = x;
RB_GNUC_EXTENSION DSIZE_T dy = y;
RB_GNUC_EXTENSION DSIZE_T dz = dx * dy;
ret.left = dz > SIZE_MAX;
ret.right = RBIMPL_CAST((size_t)dz);
#elif defined(_MSC_VER) && defined(_WIN64)
unsigned __int64 dp = 0;
unsigned __int64 dz = _umul128(x, y, &dp);
ret.left = RBIMPL_CAST((bool)dp);
ret.right = RBIMPL_CAST((size_t)dz);
#else
/* https://wiki.sei.cmu.edu/confluence/display/c/INT30-C.+Ensure+that+unsigned+integer+operations+do+not+wrap */
ret.left = (y != 0) && (x > SIZE_MAX / y);
ret.right = x * y;
#endif
return ret;
}
static inline size_t
rbimpl_size_mul_or_raise(size_t x, size_t y)
{
struct rbimpl_size_mul_overflow_tag size =
rbimpl_size_mul_overflow(x, y);
if (RB_LIKELY(! size.left)) {
return size.right;
}
else {
ruby_malloc_size_overflow(x, y);
RBIMPL_UNREACHABLE_RETURN(0);
}
}
static inline void *
rb_alloc_tmp_buffer2(volatile VALUE *store, long count, size_t elsize)
{
const size_t total_size = rbimpl_size_mul_or_raise(count, elsize);
const size_t cnt = (total_size + sizeof(VALUE) - 1) / sizeof(VALUE);
return rb_alloc_tmp_buffer_with_count(store, total_size, cnt);
}
#ifndef __MINGW32__
RBIMPL_SYMBOL_EXPORT_BEGIN()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
RBIMPL_ATTR_RETURNS_NONNULL()
/* At least since 2004, glibc's <string.h> annotates memcpy to be
* __attribute__((__nonnull__(1, 2))). However it is safe to pass NULL to the
* source pointer, if n is 0. Let's wrap memcpy. */
static inline void *
ruby_nonempty_memcpy(void *dest, const void *src, size_t n)
{
if (n) {
return memcpy(dest, src, n);
}
else {
return dest;
}
}
RBIMPL_SYMBOL_EXPORT_END()
#undef memcpy
#define memcpy ruby_nonempty_memcpy
#endif
#endif /* RBIMPL_MEMORY_H */