gecko/js/src/jsutil.h

381 lines
9.7 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/*
* PR assertion checker.
*/
#ifndef jsutil_h
#define jsutil_h
#include "mozilla/Assertions.h"
#include "mozilla/Compiler.h"
#include "mozilla/GuardObjects.h"
#include <limits.h>
#include "js/Utility.h"
#define JS_ALWAYS_TRUE(expr) MOZ_ALWAYS_TRUE(expr)
#define JS_ALWAYS_FALSE(expr) MOZ_ALWAYS_FALSE(expr)
#if defined(JS_DEBUG)
# define JS_DIAGNOSTICS_ASSERT(expr) MOZ_ASSERT(expr)
#elif defined(JS_CRASH_DIAGNOSTICS)
# define JS_DIAGNOSTICS_ASSERT(expr) do { if (MOZ_UNLIKELY(!(expr))) MOZ_CRASH(); } while(0)
#else
# define JS_DIAGNOSTICS_ASSERT(expr) ((void) 0)
#endif
static MOZ_ALWAYS_INLINE void *
js_memcpy(void *dst_, const void *src_, size_t len)
{
char *dst = (char *) dst_;
const char *src = (const char *) src_;
JS_ASSERT_IF(dst >= src, (size_t) (dst - src) >= len);
JS_ASSERT_IF(src >= dst, (size_t) (src - dst) >= len);
return memcpy(dst, src, len);
}
namespace js {
template <class T>
struct AlignmentTestStruct
{
char c;
T t;
};
/* This macro determines the alignment requirements of a type. */
#define JS_ALIGNMENT_OF(t_) \
(sizeof(js::AlignmentTestStruct<t_>) - sizeof(t_))
template <class T>
class AlignedPtrAndFlag
{
uintptr_t bits;
public:
AlignedPtrAndFlag(T *t, bool aFlag) {
JS_ASSERT((uintptr_t(t) & 1) == 0);
bits = uintptr_t(t) | uintptr_t(aFlag);
}
T *ptr() const {
return (T *)(bits & ~uintptr_t(1));
}
bool flag() const {
return (bits & 1) != 0;
}
void setPtr(T *t) {
JS_ASSERT((uintptr_t(t) & 1) == 0);
bits = uintptr_t(t) | uintptr_t(flag());
}
void setFlag() {
bits |= 1;
}
void unsetFlag() {
bits &= ~uintptr_t(1);
}
void set(T *t, bool aFlag) {
JS_ASSERT((uintptr_t(t) & 1) == 0);
bits = uintptr_t(t) | aFlag;
}
};
template <class T>
static inline void
Reverse(T *beg, T *end)
{
while (beg != end) {
if (--end == beg)
return;
T tmp = *beg;
*beg = *end;
*end = tmp;
++beg;
}
}
template <class T>
static inline T *
Find(T *beg, T *end, const T &v)
{
for (T *p = beg; p != end; ++p) {
if (*p == v)
return p;
}
return end;
}
template <class Container>
static inline typename Container::ElementType *
Find(Container &c, const typename Container::ElementType &v)
{
return Find(c.begin(), c.end(), v);
}
template <typename InputIterT, typename CallableT>
void
ForEach(InputIterT begin, InputIterT end, CallableT f)
{
for (; begin != end; ++begin)
f(*begin);
}
template <class T>
static inline T
Min(T t1, T t2)
{
return t1 < t2 ? t1 : t2;
}
template <class T>
static inline T
Max(T t1, T t2)
{
return t1 > t2 ? t1 : t2;
}
/* Allows a const variable to be initialized after its declaration. */
template <class T>
static T&
InitConst(const T &t)
{
return const_cast<T &>(t);
}
template <class T, class U>
MOZ_ALWAYS_INLINE T &
ImplicitCast(U &u)
{
T &t = u;
return t;
}
template<typename T>
class AutoScopedAssign
{
public:
AutoScopedAssign(T *addr, const T &value
MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
: addr_(addr), old(*addr_)
{
MOZ_GUARD_OBJECT_NOTIFIER_INIT;
*addr_ = value;
}
~AutoScopedAssign() { *addr_ = old; }
private:
MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
T *addr_;
T old;
};
template <typename T>
static inline bool
IsPowerOfTwo(T t)
{
return t && !(t & (t - 1));
}
template <typename T, typename U>
static inline U
ComputeByteAlignment(T bytes, U alignment)
{
JS_ASSERT(IsPowerOfTwo(alignment));
return (alignment - (bytes % alignment)) % alignment;
}
template <typename T, typename U>
static inline T
AlignBytes(T bytes, U alignment)
{
return bytes + ComputeByteAlignment(bytes, alignment);
}
static MOZ_ALWAYS_INLINE size_t
UnsignedPtrDiff(const void *bigger, const void *smaller)
{
return size_t(bigger) - size_t(smaller);
}
/*****************************************************************************/
/* A bit array is an array of bits represented by an array of words (size_t). */
static const size_t BitArrayElementBits = sizeof(size_t) * CHAR_BIT;
static inline unsigned
NumWordsForBitArrayOfLength(size_t length)
{
return (length + (BitArrayElementBits - 1)) / BitArrayElementBits;
}
static inline unsigned
BitArrayIndexToWordIndex(size_t length, size_t bitIndex)
{
unsigned wordIndex = bitIndex / BitArrayElementBits;
JS_ASSERT(wordIndex < length);
return wordIndex;
}
static inline size_t
BitArrayIndexToWordMask(size_t i)
{
return size_t(1) << (i % BitArrayElementBits);
}
static inline bool
IsBitArrayElementSet(size_t *array, size_t length, size_t i)
{
return array[BitArrayIndexToWordIndex(length, i)] & BitArrayIndexToWordMask(i);
}
static inline bool
IsAnyBitArrayElementSet(size_t *array, size_t length)
{
unsigned numWords = NumWordsForBitArrayOfLength(length);
for (unsigned i = 0; i < numWords; ++i) {
if (array[i])
return true;
}
return false;
}
static inline void
SetBitArrayElement(size_t *array, size_t length, size_t i)
{
array[BitArrayIndexToWordIndex(length, i)] |= BitArrayIndexToWordMask(i);
}
static inline void
ClearBitArrayElement(size_t *array, size_t length, size_t i)
{
array[BitArrayIndexToWordIndex(length, i)] &= ~BitArrayIndexToWordMask(i);
}
static inline void
ClearAllBitArrayElements(size_t *array, size_t length)
{
for (unsigned i = 0; i < length; ++i)
array[i] = 0;
}
} /* namespace js */
static inline void *
Poison(void *ptr, int value, size_t num)
{
static bool inited = false;
static bool poison = true;
if (!inited) {
char *env = getenv("JSGC_DISABLE_POISONING");
if (env)
poison = false;
inited = true;
}
if (poison)
return memset(ptr, value, num);
return nullptr;
}
/* Crash diagnostics */
#ifdef DEBUG
# define JS_CRASH_DIAGNOSTICS 1
#endif
#if defined(JS_CRASH_DIAGNOSTICS) || defined(JS_GC_ZEAL)
# define JS_POISON(p, val, size) Poison(p, val, size)
#else
# define JS_POISON(p, val, size) ((void) 0)
#endif
/* Bug 984101: Disable labeled poisoning until we have poison checking. */
#define JS_EXTRA_POISON(p, val, size) ((void) 0)
/* Basic stats */
#ifdef DEBUG
# define JS_BASIC_STATS 1
#endif
#ifdef JS_BASIC_STATS
# include <stdio.h>
typedef struct JSBasicStats {
uint32_t num;
uint32_t max;
double sum;
double sqsum;
uint32_t logscale; /* logarithmic scale: 0 (linear), 2, 10 */
uint32_t hist[11];
} JSBasicStats;
# define JS_INIT_STATIC_BASIC_STATS {0,0,0,0,0,{0,0,0,0,0,0,0,0,0,0,0}}
# define JS_BASIC_STATS_INIT(bs) memset((bs), 0, sizeof(JSBasicStats))
# define JS_BASIC_STATS_ACCUM(bs,val) \
JS_BasicStatsAccum(bs, val)
# define JS_MeanAndStdDevBS(bs,sigma) \
JS_MeanAndStdDev((bs)->num, (bs)->sum, (bs)->sqsum, sigma)
extern void
JS_BasicStatsAccum(JSBasicStats *bs, uint32_t val);
extern double
JS_MeanAndStdDev(uint32_t num, double sum, double sqsum, double *sigma);
extern void
JS_DumpBasicStats(JSBasicStats *bs, const char *title, FILE *fp);
extern void
JS_DumpHistogram(JSBasicStats *bs, FILE *fp);
#else
# define JS_BASIC_STATS_ACCUM(bs,val)
#endif
/* A jsbitmap_t is a long integer that can be used for bitmaps. */
typedef size_t jsbitmap;
#define JS_BITMAP_NBITS (sizeof(jsbitmap) * CHAR_BIT)
#define JS_TEST_BIT(_map,_bit) ((_map)[(_bit)/JS_BITMAP_NBITS] & \
(jsbitmap(1)<<((_bit)%JS_BITMAP_NBITS)))
#define JS_SET_BIT(_map,_bit) ((_map)[(_bit)/JS_BITMAP_NBITS] |= \
(jsbitmap(1)<<((_bit)%JS_BITMAP_NBITS)))
#define JS_CLEAR_BIT(_map,_bit) ((_map)[(_bit)/JS_BITMAP_NBITS] &= \
~(jsbitmap(1)<<((_bit)%JS_BITMAP_NBITS)))
/* Wrapper for various macros to stop warnings coming from their expansions. */
#if defined(__clang__)
# define JS_SILENCE_UNUSED_VALUE_IN_EXPR(expr) \
JS_BEGIN_MACRO \
_Pragma("clang diagnostic push") \
/* If these _Pragmas cause warnings for you, try disabling ccache. */ \
_Pragma("clang diagnostic ignored \"-Wunused-value\"") \
{ expr; } \
_Pragma("clang diagnostic pop") \
JS_END_MACRO
#elif MOZ_IS_GCC
#if MOZ_GCC_VERSION_AT_LEAST(4, 6, 0)
# define JS_SILENCE_UNUSED_VALUE_IN_EXPR(expr) \
JS_BEGIN_MACRO \
_Pragma("GCC diagnostic push") \
_Pragma("GCC diagnostic ignored \"-Wunused-but-set-variable\"") \
expr; \
_Pragma("GCC diagnostic pop") \
JS_END_MACRO
#endif
#endif
#if !defined(JS_SILENCE_UNUSED_VALUE_IN_EXPR)
# define JS_SILENCE_UNUSED_VALUE_IN_EXPR(expr) \
JS_BEGIN_MACRO \
expr; \
JS_END_MACRO
#endif
#endif /* jsutil_h */