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Use thread-local RNG for Math.random() (511328, r=shaver,waldo).
This commit is contained in:
Andreas Gal
parent
0c97581323
commit
b4232322c2
@ -58,6 +58,7 @@
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#include "jsfun.h"
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#include "jsgc.h"
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#include "jslock.h"
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#include "jsmath.h"
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#include "jsnum.h"
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#include "jsobj.h"
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#include "jsopcode.h"
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@ -83,6 +84,7 @@ InitThreadData(JSThreadData *data)
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#ifdef JS_TRACER
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js_InitJIT(&data->traceMonitor);
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#endif
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js_InitRandom(data);
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}
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static void
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@ -250,6 +250,9 @@ struct JSThreadData {
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/* Property cache for faster call/get/set invocation. */
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JSPropertyCache propertyCache;
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/* Random number generator state, used by jsmath.cpp. */
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int64 rngSeed;
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#ifdef JS_TRACER
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/* Trace-tree JIT recorder/interpreter state. */
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JSTraceMonitor traceMonitor;
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@ -456,14 +459,6 @@ struct JSRuntime {
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*/
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JSSetSlotRequest *setSlotRequests;
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/* Random number generator state, used by jsmath.c. */
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JSBool rngInitialized;
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int64 rngMultiplier;
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int64 rngAddend;
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int64 rngMask;
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int64 rngSeed;
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jsdouble rngDscale;
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/* Well-known numbers held for use by this runtime's contexts. */
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jsdouble *jsNaN;
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jsdouble *jsNegativeInfinity;
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@ -427,90 +427,47 @@ math_pow(JSContext *cx, uintN argc, jsval *vp)
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return js_NewNumberInRootedValue(cx, z, vp);
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}
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static const int64 RNG_MULTIPLIER = 0x5DEECE66DLL;
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static const int64 RNG_ADDEND = 0xBLL;
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static const int64 RNG_MASK = (1LL << 48) - 1;
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static const jsdouble RNG_DSCALE = jsdouble(1LL << 53);
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/*
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* Math.random() support, lifted from java.util.Random.java.
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*/
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static void
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random_setSeed(JSRuntime *rt, int64 seed)
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static inline void
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random_setSeed(JSThreadData *data, int64 seed)
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{
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int64 tmp;
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JSLL_I2L(tmp, 1000);
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JSLL_DIV(seed, seed, tmp);
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JSLL_XOR(tmp, seed, rt->rngMultiplier);
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JSLL_AND(rt->rngSeed, tmp, rt->rngMask);
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data->rngSeed = (seed ^ RNG_MULTIPLIER) & RNG_MASK;
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}
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void
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js_random_init(JSRuntime *rt)
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js_InitRandom(JSThreadData *data)
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{
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int64 tmp, tmp2;
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/* Do at most once. */
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if (rt->rngInitialized)
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return;
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rt->rngInitialized = JS_TRUE;
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/* rt->rngMultiplier = 0x5DEECE66DL */
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JSLL_ISHL(tmp, 0x5, 32);
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JSLL_UI2L(tmp2, 0xDEECE66DL);
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JSLL_OR(rt->rngMultiplier, tmp, tmp2);
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/* rt->rngAddend = 0xBL */
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JSLL_I2L(rt->rngAddend, 0xBL);
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/* rt->rngMask = (1L << 48) - 1 */
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JSLL_I2L(tmp, 1);
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JSLL_SHL(tmp2, tmp, 48);
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JSLL_SUB(rt->rngMask, tmp2, tmp);
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/* rt->rngDscale = (jsdouble)(1L << 53) */
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JSLL_SHL(tmp2, tmp, 53);
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JSLL_L2D(rt->rngDscale, tmp2);
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/* Finally, set the seed from current time. */
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random_setSeed(rt, PRMJ_Now());
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random_setSeed(data, PRMJ_Now() / 1000);
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}
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static uint32
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random_next(JSRuntime *rt, int bits)
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static inline uint64
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random_next(JSThreadData *data, int bits)
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{
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int64 nextseed, tmp;
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uint32 retval;
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JSLL_MUL(nextseed, rt->rngSeed, rt->rngMultiplier);
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JSLL_ADD(nextseed, nextseed, rt->rngAddend);
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JSLL_AND(nextseed, nextseed, rt->rngMask);
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rt->rngSeed = nextseed;
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JSLL_USHR(tmp, nextseed, 48 - bits);
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JSLL_L2I(retval, tmp);
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return retval;
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uint64 nextseed = data->rngSeed * RNG_MULTIPLIER;
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nextseed += RNG_ADDEND;
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nextseed &= RNG_MASK;
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data->rngSeed = nextseed;
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return nextseed >> (48 - bits);
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}
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jsdouble
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js_random_nextDouble(JSRuntime *rt)
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static inline jsdouble
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random_nextDouble(JSThreadData *data)
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{
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int64 tmp, tmp2;
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jsdouble d;
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JSLL_ISHL(tmp, random_next(rt, 26), 27);
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JSLL_UI2L(tmp2, random_next(rt, 27));
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JSLL_ADD(tmp, tmp, tmp2);
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JSLL_L2D(d, tmp);
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return d / rt->rngDscale;
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return jsdouble((random_next(data, 26) << 27) + random_next(data, 27)) / RNG_DSCALE;
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}
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static JSBool
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math_random(JSContext *cx, uintN argc, jsval *vp)
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{
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JSRuntime *rt;
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jsdouble z;
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rt = cx->runtime;
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JS_LOCK_RUNTIME(rt);
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js_random_init(rt);
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z = js_random_nextDouble(rt);
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JS_UNLOCK_RUNTIME(rt);
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jsdouble z = random_nextDouble(JS_THREAD_DATA(cx));
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return js_NewNumberInRootedValue(cx, z, vp);
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}
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@ -716,13 +673,9 @@ math_pow_tn(jsdouble d, jsdouble p)
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}
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static jsdouble FASTCALL
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math_random_tn(JSRuntime* rt)
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math_random_tn(JSContext *cx)
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{
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JS_LOCK_RUNTIME(rt);
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js_random_init(rt);
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jsdouble z = js_random_nextDouble(rt);
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JS_UNLOCK_RUNTIME(rt);
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return z;
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return random_nextDouble(JS_THREAD_DATA(cx));
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}
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static jsdouble FASTCALL
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@ -752,7 +705,7 @@ JS_DEFINE_TRCINFO_1(math_min,
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JS_DEFINE_TRCINFO_1(math_pow,
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(2, (static, DOUBLE, math_pow_tn, DOUBLE, DOUBLE, 1, 1)))
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JS_DEFINE_TRCINFO_1(math_random,
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(1, (static, DOUBLE, math_random_tn, RUNTIME, 0, 0)))
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(1, (static, DOUBLE, math_random_tn, CONTEXT, 0, 0)))
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JS_DEFINE_TRCINFO_1(math_round,
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(1, (static, DOUBLE, math_round_tn, DOUBLE, 1, 1)))
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JS_DEFINE_TRCINFO_1(math_ceil,
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@ -51,10 +51,7 @@ extern JSObject *
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js_InitMathClass(JSContext *cx, JSObject *obj);
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extern void
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js_random_init(JSRuntime *rt);
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extern jsdouble
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js_random_nextDouble(JSRuntime *rt);
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js_InitRandom(JSThreadData *data);
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JS_END_EXTERN_C
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