deps: update V8 to 7.4.288.13

PR-URL: https://github.com/nodejs/node/pull/26685
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>

14 files changed, 603 insertions, 62 deletions

diff --git a/deps/v8/src/base/division-by-constant.cc b/deps/v8/src/base/division-by-constant.cc
index 4e0900fa24..7aa3a69014 100644
--- a/deps/v8/src/base/division-by-constant.cc
+++ b/deps/v8/src/base/division-by-constant.cc
@@ -93,16 +93,22 @@ MagicNumbersForDivision<T> UnsignedDivisionByConstant(T d,
 // -----------------------------------------------------------------------------
 // Instantiations.
 
-template struct V8_BASE_EXPORT MagicNumbersForDivision<uint32_t>;
-template struct V8_BASE_EXPORT MagicNumbersForDivision<uint64_t>;
+template struct EXPORT_TEMPLATE_DEFINE(V8_BASE_EXPORT)
+    MagicNumbersForDivision<uint32_t>;
+template struct EXPORT_TEMPLATE_DEFINE(V8_BASE_EXPORT)
+    MagicNumbersForDivision<uint64_t>;
 
-template MagicNumbersForDivision<uint32_t> SignedDivisionByConstant(uint32_t d);
-template MagicNumbersForDivision<uint64_t> SignedDivisionByConstant(uint64_t d);
+template EXPORT_TEMPLATE_DEFINE(V8_BASE_EXPORT)
+    MagicNumbersForDivision<uint32_t> SignedDivisionByConstant(uint32_t d);
+template EXPORT_TEMPLATE_DEFINE(V8_BASE_EXPORT)
+    MagicNumbersForDivision<uint64_t> SignedDivisionByConstant(uint64_t d);
 
-template MagicNumbersForDivision<uint32_t> UnsignedDivisionByConstant(
-    uint32_t d, unsigned leading_zeros);
-template MagicNumbersForDivision<uint64_t> UnsignedDivisionByConstant(
-    uint64_t d, unsigned leading_zeros);
+template EXPORT_TEMPLATE_DEFINE(V8_BASE_EXPORT)
+    MagicNumbersForDivision<uint32_t> UnsignedDivisionByConstant(
+        uint32_t d, unsigned leading_zeros);
+template EXPORT_TEMPLATE_DEFINE(V8_BASE_EXPORT)
+    MagicNumbersForDivision<uint64_t> UnsignedDivisionByConstant(
+        uint64_t d, unsigned leading_zeros);
 
 }  // namespace base
 }  // namespace v8
diff --git a/deps/v8/src/base/division-by-constant.h b/deps/v8/src/base/division-by-constant.h
index 5d063f8bd5..744283981b 100644
--- a/deps/v8/src/base/division-by-constant.h
+++ b/deps/v8/src/base/division-by-constant.h
@@ -8,6 +8,7 @@
 #include <stdint.h>
 
 #include "src/base/base-export.h"
+#include "src/base/export-template.h"
 
 namespace v8 {
 namespace base {
@@ -18,7 +19,7 @@ namespace base {
 // Delight", chapter 10. The template parameter must be one of the unsigned
 // integral types.
 template <class T>
-struct V8_BASE_EXPORT MagicNumbersForDivision {
+struct EXPORT_TEMPLATE_DECLARE(V8_BASE_EXPORT) MagicNumbersForDivision {
   MagicNumbersForDivision(T m, unsigned s, bool a)
       : multiplier(m), shift(s), add(a) {}
   bool operator==(const MagicNumbersForDivision& rhs) const {
@@ -34,25 +35,35 @@ struct V8_BASE_EXPORT MagicNumbersForDivision {
 // Calculate the multiplier and shift for signed division via multiplication.
 // The divisor must not be -1, 0 or 1 when interpreted as a signed value.
 template <class T>
-V8_BASE_EXPORT MagicNumbersForDivision<T> SignedDivisionByConstant(T d);
+EXPORT_TEMPLATE_DECLARE(V8_BASE_EXPORT)
+MagicNumbersForDivision<T> SignedDivisionByConstant(T d);
 
 // Calculate the multiplier and shift for unsigned division via multiplication,
 // see Warren's "Hacker's Delight", chapter 10. The divisor must not be 0 and
 // leading_zeros can be used to speed up the calculation if the given number of
 // upper bits of the dividend value are known to be zero.
 template <class T>
-V8_BASE_EXPORT MagicNumbersForDivision<T> UnsignedDivisionByConstant(
+EXPORT_TEMPLATE_DECLARE(V8_BASE_EXPORT)
+MagicNumbersForDivision<T> UnsignedDivisionByConstant(
     T d, unsigned leading_zeros = 0);
 
-extern template V8_BASE_EXPORT MagicNumbersForDivision<uint32_t>
-SignedDivisionByConstant(uint32_t d);
-extern template V8_BASE_EXPORT MagicNumbersForDivision<uint64_t>
-SignedDivisionByConstant(uint64_t d);
+// Explicit instantiation declarations.
+extern template struct EXPORT_TEMPLATE_DECLARE(V8_BASE_EXPORT)
+    MagicNumbersForDivision<uint32_t>;
+extern template struct EXPORT_TEMPLATE_DECLARE(V8_BASE_EXPORT)
+    MagicNumbersForDivision<uint64_t>;
 
-extern template V8_BASE_EXPORT MagicNumbersForDivision<uint32_t>
-UnsignedDivisionByConstant(uint32_t d, unsigned leading_zeros);
-extern template V8_BASE_EXPORT MagicNumbersForDivision<uint64_t>
-UnsignedDivisionByConstant(uint64_t d, unsigned leading_zeros);
+extern template EXPORT_TEMPLATE_DECLARE(V8_BASE_EXPORT)
+    MagicNumbersForDivision<uint32_t> SignedDivisionByConstant(uint32_t d);
+extern template EXPORT_TEMPLATE_DECLARE(V8_BASE_EXPORT)
+    MagicNumbersForDivision<uint64_t> SignedDivisionByConstant(uint64_t d);
+
+extern template EXPORT_TEMPLATE_DECLARE(V8_BASE_EXPORT)
+    MagicNumbersForDivision<uint32_t> UnsignedDivisionByConstant(
+        uint32_t d, unsigned leading_zeros);
+extern template EXPORT_TEMPLATE_DECLARE(V8_BASE_EXPORT)
+    MagicNumbersForDivision<uint64_t> UnsignedDivisionByConstant(
+        uint64_t d, unsigned leading_zeros);
 
 }  // namespace base
 }  // namespace v8
diff --git a/deps/v8/src/base/ieee754.cc b/deps/v8/src/base/ieee754.cc
index d9846b7254..4fcb4df001 100644
--- a/deps/v8/src/base/ieee754.cc
+++ b/deps/v8/src/base/ieee754.cc
@@ -309,7 +309,7 @@ int32_t __ieee754_rem_pio2(double x, double *y) {
   GET_LOW_WORD(low, x);
   SET_LOW_WORD(z, low);
   e0 = (ix >> 20) - 1046; /* e0 = ilogb(z)-23; */
-  SET_HIGH_WORD(z, ix - static_cast<int32_t>(e0 << 20));
+  SET_HIGH_WORD(z, ix - static_cast<int32_t>(static_cast<uint32_t>(e0) << 20));
   for (i = 0; i < 2; i++) {
     tx[i] = static_cast<double>(static_cast<int32_t>(z));
     z = (z - tx[i]) * two24;
@@ -1569,9 +1569,12 @@ double exp(double x) {
   /* x is now in primary range */
   t = x * x;
   if (k >= -1021) {
-    INSERT_WORDS(twopk, 0x3FF00000 + (k << 20), 0);
+    INSERT_WORDS(
+        twopk,
+        0x3FF00000 + static_cast<int32_t>(static_cast<uint32_t>(k) << 20), 0);
   } else {
-    INSERT_WORDS(twopk, 0x3FF00000 + ((k + 1000) << 20), 0);
+    INSERT_WORDS(twopk, 0x3FF00000 + (static_cast<uint32_t>(k + 1000) << 20),
+                 0);
   }
   c = x - t * (P1 + t * (P2 + t * (P3 + t * (P4 + t * P5))));
   if (k == 0) {
@@ -2341,7 +2344,10 @@ double expm1(double x) {
   if (k == 0) {
     return x - (x * e - hxs); /* c is 0 */
   } else {
-    INSERT_WORDS(twopk, 0x3FF00000 + (k << 20), 0); /* 2^k */
+    INSERT_WORDS(
+        twopk,
+        0x3FF00000 + static_cast<int32_t>(static_cast<uint32_t>(k) << 20),
+        0); /* 2^k */
     e = (x * (e - c) - c);
     e -= hxs;
     if (k == -1) return 0.5 * (x - e) - 0.5;
@@ -2642,6 +2648,317 @@ double cosh(double x) {
 }
 
 /*
+ * ES2019 Draft 2019-01-02 12.6.4
+ * Math.pow & Exponentiation Operator
+ *
+ * Return X raised to the Yth power
+ *
+ * Method:
+ *     Let x =  2   * (1+f)
+ *     1. Compute and return log2(x) in two pieces:
+ *        log2(x) = w1 + w2,
+ *        where w1 has 53-24 = 29 bit trailing zeros.
+ *     2. Perform y*log2(x) = n+y' by simulating muti-precision
+ *        arithmetic, where |y'|<=0.5.
+ *     3. Return x**y = 2**n*exp(y'*log2)
+ *
+ * Special cases:
+ *     1.  (anything) ** 0  is 1
+ *     2.  (anything) ** 1  is itself
+ *     3.  (anything) ** NAN is NAN
+ *     4.  NAN ** (anything except 0) is NAN
+ *     5.  +-(|x| > 1) **  +INF is +INF
+ *     6.  +-(|x| > 1) **  -INF is +0
+ *     7.  +-(|x| < 1) **  +INF is +0
+ *     8.  +-(|x| < 1) **  -INF is +INF
+ *     9.  +-1         ** +-INF is NAN
+ *     10. +0 ** (+anything except 0, NAN)               is +0
+ *     11. -0 ** (+anything except 0, NAN, odd integer)  is +0
+ *     12. +0 ** (-anything except 0, NAN)               is +INF
+ *     13. -0 ** (-anything except 0, NAN, odd integer)  is +INF
+ *     14. -0 ** (odd integer) = -( +0 ** (odd integer) )
+ *     15. +INF ** (+anything except 0,NAN) is +INF
+ *     16. +INF ** (-anything except 0,NAN) is +0
+ *     17. -INF ** (anything)  = -0 ** (-anything)
+ *     18. (-anything) ** (integer) is (-1)**(integer)*(+anything**integer)
+ *     19. (-anything except 0 and inf) ** (non-integer) is NAN
+ *
+ * Accuracy:
+ *      pow(x,y) returns x**y nearly rounded. In particular,
+ *      pow(integer, integer) always returns the correct integer provided it is
+ *      representable.
+ *
+ * Constants:
+ *     The hexadecimal values are the intended ones for the following
+ *     constants. The decimal values may be used, provided that the
+ *     compiler will convert from decimal to binary accurately enough
+ *     to produce the hexadecimal values shown.
+ */
+
+double pow(double x, double y) {
+  static const double
+      bp[] = {1.0, 1.5},
+      dp_h[] = {0.0, 5.84962487220764160156e-01},  // 0x3FE2B803, 0x40000000
+      dp_l[] = {0.0, 1.35003920212974897128e-08},  // 0x3E4CFDEB, 0x43CFD006
+      zero = 0.0, one = 1.0, two = 2.0,
+      two53 = 9007199254740992.0,  // 0x43400000, 0x00000000
+      huge = 1.0e300, tiny = 1.0e-300,
+      // poly coefs for (3/2)*(log(x)-2s-2/3*s**3
+      L1 = 5.99999999999994648725e-01,      // 0x3FE33333, 0x33333303
+      L2 = 4.28571428578550184252e-01,      // 0x3FDB6DB6, 0xDB6FABFF
+      L3 = 3.33333329818377432918e-01,      // 0x3FD55555, 0x518F264D
+      L4 = 2.72728123808534006489e-01,      // 0x3FD17460, 0xA91D4101
+      L5 = 2.30660745775561754067e-01,      // 0x3FCD864A, 0x93C9DB65
+      L6 = 2.06975017800338417784e-01,      // 0x3FCA7E28, 0x4A454EEF
+      P1 = 1.66666666666666019037e-01,      // 0x3FC55555, 0x5555553E
+      P2 = -2.77777777770155933842e-03,     // 0xBF66C16C, 0x16BEBD93
+      P3 = 6.61375632143793436117e-05,      // 0x3F11566A, 0xAF25DE2C
+      P4 = -1.65339022054652515390e-06,     // 0xBEBBBD41, 0xC5D26BF1
+      P5 = 4.13813679705723846039e-08,      // 0x3E663769, 0x72BEA4D0
+      lg2 = 6.93147180559945286227e-01,     // 0x3FE62E42, 0xFEFA39EF
+      lg2_h = 6.93147182464599609375e-01,   // 0x3FE62E43, 0x00000000
+      lg2_l = -1.90465429995776804525e-09,  // 0xBE205C61, 0x0CA86C39
+      ovt = 8.0085662595372944372e-0017,    // -(1024-log2(ovfl+.5ulp))
+      cp = 9.61796693925975554329e-01,      // 0x3FEEC709, 0xDC3A03FD =2/(3ln2)
+      cp_h = 9.61796700954437255859e-01,    // 0x3FEEC709, 0xE0000000 =(float)cp
+      cp_l = -7.02846165095275826516e-09,   // 0xBE3E2FE0, 0x145B01F5 =tail cp_h
+      ivln2 = 1.44269504088896338700e+00,   // 0x3FF71547, 0x652B82FE =1/ln2
+      ivln2_h =
+          1.44269502162933349609e+00,  // 0x3FF71547, 0x60000000 =24b 1/ln2
+      ivln2_l =
+          1.92596299112661746887e-08;  // 0x3E54AE0B, 0xF85DDF44 =1/ln2 tail
+
+  double z, ax, z_h, z_l, p_h, p_l;
+  double y1, t1, t2, r, s, t, u, v, w;
+  int i, j, k, yisint, n;
+  int hx, hy, ix, iy;
+  unsigned lx, ly;
+
+  EXTRACT_WORDS(hx, lx, x);
+  EXTRACT_WORDS(hy, ly, y);
+  ix = hx & 0x7fffffff;
+  iy = hy & 0x7fffffff;
+
+  /* y==zero: x**0 = 1 */
+  if ((iy | ly) == 0) return one;
+
+  /* +-NaN return x+y */
+  if (ix > 0x7ff00000 || ((ix == 0x7ff00000) && (lx != 0)) || iy > 0x7ff00000 ||
+      ((iy == 0x7ff00000) && (ly != 0))) {
+    return x + y;
+  }
+
+  /* determine if y is an odd int when x < 0
+   * yisint = 0 ... y is not an integer
+   * yisint = 1 ... y is an odd int
+   * yisint = 2 ... y is an even int
+   */
+  yisint = 0;
+  if (hx < 0) {
+    if (iy >= 0x43400000) {
+      yisint = 2; /* even integer y */
+    } else if (iy >= 0x3ff00000) {
+      k = (iy >> 20) - 0x3ff; /* exponent */
+      if (k > 20) {
+        j = ly >> (52 - k);
+        if ((j << (52 - k)) == static_cast<int>(ly)) yisint = 2 - (j & 1);
+      } else if (ly == 0) {
+        j = iy >> (20 - k);
+        if ((j << (20 - k)) == iy) yisint = 2 - (j & 1);
+      }
+    }
+  }
+
+  /* special value of y */
+  if (ly == 0) {
+    if (iy == 0x7ff00000) { /* y is +-inf */
+      if (((ix - 0x3ff00000) | lx) == 0) {
+        return y - y;                /* inf**+-1 is NaN */
+      } else if (ix >= 0x3ff00000) { /* (|x|>1)**+-inf = inf,0 */
+        return (hy >= 0) ? y : zero;
+      } else { /* (|x|<1)**-,+inf = inf,0 */
+        return (hy < 0) ? -y : zero;
+      }
+    }
+    if (iy == 0x3ff00000) { /* y is  +-1 */
+      if (hy < 0) {
+        return base::Divide(one, x);
+      } else {
+        return x;
+      }
+    }
+    if (hy == 0x40000000) return x * x; /* y is  2 */
+    if (hy == 0x3fe00000) {             /* y is  0.5 */
+      if (hx >= 0) {                    /* x >= +0 */
+        return sqrt(x);
+      }
+    }
+  }
+
+  ax = fabs(x);
+  /* special value of x */
+  if (lx == 0) {
+    if (ix == 0x7ff00000 || ix == 0 || ix == 0x3ff00000) {
+      z = ax;                         /*x is +-0,+-inf,+-1*/
+      if (hy < 0) z = base::Divide(one, z); /* z = (1/|x|) */
+      if (hx < 0) {
+        if (((ix - 0x3ff00000) | yisint) == 0) {
+          /* (-1)**non-int is NaN */
+          z = std::numeric_limits<double>::signaling_NaN();
+        } else if (yisint == 1) {
+          z = -z; /* (x<0)**odd = -(|x|**odd) */
+        }
+      }
+      return z;
+    }
+  }
+
+  n = (hx >> 31) + 1;
+
+  /* (x<0)**(non-int) is NaN */
+  if ((n | yisint) == 0) {
+    return std::numeric_limits<double>::signaling_NaN();
+  }
+
+  s = one; /* s (sign of result -ve**odd) = -1 else = 1 */
+  if ((n | (yisint - 1)) == 0) s = -one; /* (-ve)**(odd int) */
+
+  /* |y| is huge */
+  if (iy > 0x41e00000) {   /* if |y| > 2**31 */
+    if (iy > 0x43f00000) { /* if |y| > 2**64, must o/uflow */
+      if (ix <= 0x3fefffff) return (hy < 0) ? huge * huge : tiny * tiny;
+      if (ix >= 0x3ff00000) return (hy > 0) ? huge * huge : tiny * tiny;
+    }
+    /* over/underflow if x is not close to one */
+    if (ix < 0x3fefffff) return (hy < 0) ? s * huge * huge : s * tiny * tiny;
+    if (ix > 0x3ff00000) return (hy > 0) ? s * huge * huge : s * tiny * tiny;
+    /* now |1-x| is tiny <= 2**-20, suffice to compute
+       log(x) by x-x^2/2+x^3/3-x^4/4 */
+    t = ax - one; /* t has 20 trailing zeros */
+    w = (t * t) * (0.5 - t * (0.3333333333333333333333 - t * 0.25));
+    u = ivln2_h * t; /* ivln2_h has 21 sig. bits */
+    v = t * ivln2_l - w * ivln2;
+    t1 = u + v;
+    SET_LOW_WORD(t1, 0);
+    t2 = v - (t1 - u);
+  } else {
+    double ss, s2, s_h, s_l, t_h, t_l;
+    n = 0;
+    /* take care subnormal number */
+    if (ix < 0x00100000) {
+      ax *= two53;
+      n -= 53;
+      GET_HIGH_WORD(ix, ax);
+    }
+    n += ((ix) >> 20) - 0x3ff;
+    j = ix & 0x000fffff;
+    /* determine interval */
+    ix = j | 0x3ff00000; /* normalize ix */
+    if (j <= 0x3988E) {
+      k = 0; /* |x|<sqrt(3/2) */
+    } else if (j < 0xBB67A) {
+      k = 1; /* |x|<sqrt(3)   */
+    } else {
+      k = 0;
+      n += 1;
+      ix -= 0x00100000;
+    }
+    SET_HIGH_WORD(ax, ix);
+
+    /* compute ss = s_h+s_l = (x-1)/(x+1) or (x-1.5)/(x+1.5) */
+    u = ax - bp[k]; /* bp[0]=1.0, bp[1]=1.5 */
+    v = base::Divide(one, ax + bp[k]);
+    ss = u * v;
+    s_h = ss;
+    SET_LOW_WORD(s_h, 0);
+    /* t_h=ax+bp[k] High */
+    t_h = zero;
+    SET_HIGH_WORD(t_h, ((ix >> 1) | 0x20000000) + 0x00080000 + (k << 18));
+    t_l = ax - (t_h - bp[k]);
+    s_l = v * ((u - s_h * t_h) - s_h * t_l);
+    /* compute log(ax) */
+    s2 = ss * ss;
+    r = s2 * s2 *
+        (L1 + s2 * (L2 + s2 * (L3 + s2 * (L4 + s2 * (L5 + s2 * L6)))));
+    r += s_l * (s_h + ss);
+    s2 = s_h * s_h;
+    t_h = 3.0 + s2 + r;
+    SET_LOW_WORD(t_h, 0);
+    t_l = r - ((t_h - 3.0) - s2);
+    /* u+v = ss*(1+...) */
+    u = s_h * t_h;
+    v = s_l * t_h + t_l * ss;
+    /* 2/(3log2)*(ss+...) */
+    p_h = u + v;
+    SET_LOW_WORD(p_h, 0);
+    p_l = v - (p_h - u);
+    z_h = cp_h * p_h; /* cp_h+cp_l = 2/(3*log2) */
+    z_l = cp_l * p_h + p_l * cp + dp_l[k];
+    /* log2(ax) = (ss+..)*2/(3*log2) = n + dp_h + z_h + z_l */
+    t = static_cast<double>(n);
+    t1 = (((z_h + z_l) + dp_h[k]) + t);
+    SET_LOW_WORD(t1, 0);
+    t2 = z_l - (((t1 - t) - dp_h[k]) - z_h);
+  }
+
+  /* split up y into y1+y2 and compute (y1+y2)*(t1+t2) */
+  y1 = y;
+  SET_LOW_WORD(y1, 0);
+  p_l = (y - y1) * t1 + y * t2;
+  p_h = y1 * t1;
+  z = p_l + p_h;
+  EXTRACT_WORDS(j, i, z);
+  if (j >= 0x40900000) {               /* z >= 1024 */
+    if (((j - 0x40900000) | i) != 0) { /* if z > 1024 */
+      return s * huge * huge;          /* overflow */
+    } else {
+      if (p_l + ovt > z - p_h) return s * huge * huge; /* overflow */
+    }
+  } else if ((j & 0x7fffffff) >= 0x4090cc00) { /* z <= -1075 */
+    if (((j - 0xc090cc00) | i) != 0) {         /* z < -1075 */
+      return s * tiny * tiny;                  /* underflow */
+    } else {
+      if (p_l <= z - p_h) return s * tiny * tiny; /* underflow */
+    }
+  }
+  /*
+   * compute 2**(p_h+p_l)
+   */
+  i = j & 0x7fffffff;
+  k = (i >> 20) - 0x3ff;
+  n = 0;
+  if (i > 0x3fe00000) { /* if |z| > 0.5, set n = [z+0.5] */
+    n = j + (0x00100000 >> (k + 1));
+    k = ((n & 0x7fffffff) >> 20) - 0x3ff; /* new k for n */
+    t = zero;
+    SET_HIGH_WORD(t, n & ~(0x000fffff >> k));
+    n = ((n & 0x000fffff) | 0x00100000) >> (20 - k);
+    if (j < 0) n = -n;
+    p_h -= t;
+  }
+  t = p_l + p_h;
+  SET_LOW_WORD(t, 0);
+  u = t * lg2_h;
+  v = (p_l - (t - p_h)) * lg2 + t * lg2_l;
+  z = u + v;
+  w = v - (z - u);
+  t = z * z;
+  t1 = z - t * (P1 + t * (P2 + t * (P3 + t * (P4 + t * P5))));
+  r = base::Divide(z * t1, (t1 - two) - (w + z * w));
+  z = one - (r - z);
+  GET_HIGH_WORD(j, z);
+  j += static_cast<int>(static_cast<uint32_t>(n) << 20);
+  if ((j >> 20) <= 0) {
+    z = scalbn(z, n); /* subnormal output */
+  } else {
+    int tmp;
+    GET_HIGH_WORD(tmp, z);
+    SET_HIGH_WORD(z, tmp + static_cast<int>(static_cast<uint32_t>(n) << 20));
+  }
+  return s * z;
+}
+
+/*
  * ES6 draft 09-27-13, section 20.2.2.30.
  * Math.sinh
  * Method :
@@ -2752,6 +3069,16 @@ double tanh(double x) {
   return (jx >= 0) ? z : -z;
 }
 
+#undef EXTRACT_WORDS
+#undef EXTRACT_WORD64
+#undef GET_HIGH_WORD
+#undef GET_LOW_WORD
+#undef INSERT_WORDS
+#undef INSERT_WORD64
+#undef SET_HIGH_WORD
+#undef SET_LOW_WORD
+#undef STRICT_ASSIGN
+
 }  // namespace ieee754
 }  // namespace base
 }  // namespace v8
diff --git a/deps/v8/src/base/ieee754.h b/deps/v8/src/base/ieee754.h
index 72f3db15ef..f2b3a3eb58 100644
--- a/deps/v8/src/base/ieee754.h
+++ b/deps/v8/src/base/ieee754.h
@@ -60,6 +60,14 @@ V8_BASE_EXPORT double cbrt(double x);
 // Returns exp(x)-1, the exponential of |x| minus 1.
 V8_BASE_EXPORT double expm1(double x);
 
+// Returns |x| to the power of |y|.
+// The result of base ** exponent when base is 1 or -1 and exponent is
+// +Infinity or -Infinity differs from IEEE 754-2008. The first edition
+// of ECMAScript specified a result of NaN for this operation, whereas
+// later versions of IEEE 754-2008 specified 1. The historical ECMAScript
+// behaviour is preserved for compatibility reasons.
+V8_BASE_EXPORT double pow(double x, double y);
+
 // Returns the sine of |x|, where |x| is given in radians.
 V8_BASE_EXPORT double sin(double x);
 
diff --git a/deps/v8/src/base/macros.h b/deps/v8/src/base/macros.h
index 8a088ffc40..14c69d3fc2 100644
--- a/deps/v8/src/base/macros.h
+++ b/deps/v8/src/base/macros.h
@@ -146,7 +146,7 @@ V8_INLINE Dest bit_cast(Source const& source) {
 //  odr-used by the definition of the destructor of that class, [...]
 #define DISALLOW_NEW_AND_DELETE()                            \
   void* operator new(size_t) { base::OS::Abort(); }          \
-  void* operator new[](size_t) { base::OS::Abort(); };       \
+  void* operator new[](size_t) { base::OS::Abort(); }        \
   void operator delete(void*, size_t) { base::OS::Abort(); } \
   void operator delete[](void*, size_t) { base::OS::Abort(); }
 
diff --git a/deps/v8/src/base/platform/mutex.cc b/deps/v8/src/base/platform/mutex.cc
index a044075c16..2e2f7f9320 100644
--- a/deps/v8/src/base/platform/mutex.cc
+++ b/deps/v8/src/base/platform/mutex.cc
@@ -155,6 +155,45 @@ bool RecursiveMutex::TryLock() {
   return true;
 }
 
+SharedMutex::SharedMutex() { pthread_rwlock_init(&native_handle_, nullptr); }
+
+SharedMutex::~SharedMutex() {
+  int result = pthread_rwlock_destroy(&native_handle_);
+  DCHECK_EQ(0, result);
+  USE(result);
+}
+
+void SharedMutex::LockShared() {
+  int result = pthread_rwlock_rdlock(&native_handle_);
+  DCHECK_EQ(0, result);
+  USE(result);
+}
+
+void SharedMutex::LockExclusive() {
+  int result = pthread_rwlock_wrlock(&native_handle_);
+  DCHECK_EQ(0, result);
+  USE(result);
+}
+
+void SharedMutex::UnlockShared() {
+  int result = pthread_rwlock_unlock(&native_handle_);
+  DCHECK_EQ(0, result);
+  USE(result);
+}
+
+void SharedMutex::UnlockExclusive() {
+  // Same code as {UnlockShared} on POSIX.
+  UnlockShared();
+}
+
+bool SharedMutex::TryLockShared() {
+  return pthread_rwlock_tryrdlock(&native_handle_) == 0;
+}
+
+bool SharedMutex::TryLockExclusive() {
+  return pthread_rwlock_trywrlock(&native_handle_) == 0;
+}
+
 #elif V8_OS_WIN
 
 Mutex::Mutex() : native_handle_(SRWLOCK_INIT) {
@@ -233,6 +272,28 @@ bool RecursiveMutex::TryLock() {
   return true;
 }
 
+SharedMutex::SharedMutex() : native_handle_(SRWLOCK_INIT) {}
+
+SharedMutex::~SharedMutex() {}
+
+void SharedMutex::LockShared() { AcquireSRWLockShared(&native_handle_); }
+
+void SharedMutex::LockExclusive() { AcquireSRWLockExclusive(&native_handle_); }
+
+void SharedMutex::UnlockShared() { ReleaseSRWLockShared(&native_handle_); }
+
+void SharedMutex::UnlockExclusive() {
+  ReleaseSRWLockExclusive(&native_handle_);
+}
+
+bool SharedMutex::TryLockShared() {
+  return TryAcquireSRWLockShared(&native_handle_);
+}
+
+bool SharedMutex::TryLockExclusive() {
+  return TryAcquireSRWLockExclusive(&native_handle_);
+}
+
 #endif  // V8_OS_POSIX
 
 }  // namespace base
diff --git a/deps/v8/src/base/platform/mutex.h b/deps/v8/src/base/platform/mutex.h
index a69eee0bc6..ea589d5b98 100644
--- a/deps/v8/src/base/platform/mutex.h
+++ b/deps/v8/src/base/platform/mutex.h
@@ -20,7 +20,7 @@ namespace v8 {
 namespace base {
 
 // ----------------------------------------------------------------------------
-// Mutex
+// Mutex - a replacement for std::mutex
 //
 // This class is a synchronization primitive that can be used to protect shared
 // data from being simultaneously accessed by multiple threads. A mutex offers
@@ -106,9 +106,8 @@ typedef LazyStaticInstance<Mutex, DefaultConstructTrait<Mutex>,
 
 #define LAZY_MUTEX_INITIALIZER LAZY_STATIC_INSTANCE_INITIALIZER
 
-
 // -----------------------------------------------------------------------------
-// RecursiveMutex
+// RecursiveMutex - a replacement for std::recursive_mutex
 //
 // This class is a synchronization primitive that can be used to protect shared
 // data from being simultaneously accessed by multiple threads. A recursive
@@ -151,6 +150,7 @@ class V8_BASE_EXPORT RecursiveMutex final {
   // successfully locked.
   bool TryLock() V8_WARN_UNUSED_RESULT;
 
+ private:
   // The implementation-defined native handle type.
 #if V8_OS_POSIX
   typedef pthread_mutex_t NativeHandle;
@@ -158,14 +158,6 @@ class V8_BASE_EXPORT RecursiveMutex final {
   typedef CRITICAL_SECTION NativeHandle;
 #endif
 
-  NativeHandle& native_handle() {
-    return native_handle_;
-  }
-  const NativeHandle& native_handle() const {
-    return native_handle_;
-  }
-
- private:
   NativeHandle native_handle_;
 #ifdef DEBUG
   int level_;
@@ -191,6 +183,73 @@ typedef LazyStaticInstance<RecursiveMutex,
 
 #define LAZY_RECURSIVE_MUTEX_INITIALIZER LAZY_STATIC_INSTANCE_INITIALIZER
 
+// ----------------------------------------------------------------------------
+// SharedMutex - a replacement for std::shared_mutex
+//
+// This class is a synchronization primitive that can be used to protect shared
+// data from being simultaneously accessed by multiple threads. In contrast to
+// other mutex types which facilitate exclusive access, a shared_mutex has two
+// levels of access:
+// - shared: several threads can share ownership of the same mutex.
+// - exclusive: only one thread can own the mutex.
+// Shared mutexes are usually used in situations when multiple readers can
+// access the same resource at the same time without causing data races, but
+// only one writer can do so.
+// The SharedMutex class is non-copyable.
+
+class V8_BASE_EXPORT SharedMutex final {
+ public:
+  SharedMutex();
+  ~SharedMutex();
+
+  // Acquires shared ownership of the {SharedMutex}. If another thread is
+  // holding the mutex in exclusive ownership, a call to {LockShared()} will
+  // block execution until shared ownership can be acquired.
+  // If {LockShared()} is called by a thread that already owns the mutex in any
+  // mode (exclusive or shared), the behavior is undefined.
+  void LockShared();
+
+  // Locks the SharedMutex. If another thread has already locked the mutex, a
+  // call to {LockExclusive()} will block execution until the lock is acquired.
+  // If {LockExclusive()} is called by a thread that already owns the mutex in
+  // any mode (shared or exclusive), the behavior is undefined.
+  void LockExclusive();
+
+  // Releases the {SharedMutex} from shared ownership by the calling thread.
+  // The mutex must be locked by the current thread of execution in shared mode,
+  // otherwise, the behavior is undefined.
+  void UnlockShared();
+
+  // Unlocks the {SharedMutex}. It must be locked by the current thread of
+  // execution, otherwise, the behavior is undefined.
+  void UnlockExclusive();
+
+  // Tries to lock the {SharedMutex} in shared mode. Returns immediately. On
+  // successful lock acquisition returns true, otherwise returns false.
+  // This function is allowed to fail spuriously and return false even if the
+  // mutex is not currenly exclusively locked by any other thread.
+  bool TryLockShared() V8_WARN_UNUSED_RESULT;
+
+  // Tries to lock the {SharedMutex}. Returns immediately. On successful lock
+  // acquisition returns true, otherwise returns false.
+  // This function is allowed to fail spuriously and return false even if the
+  // mutex is not currently locked by any other thread.
+  // If try_lock is called by a thread that already owns the mutex in any mode
+  // (shared or exclusive), the behavior is undefined.
+  bool TryLockExclusive() V8_WARN_UNUSED_RESULT;
+
+ private:
+  // The implementation-defined native handle type.
+#if V8_OS_POSIX
+  typedef pthread_rwlock_t NativeHandle;
+#elif V8_OS_WIN
+  typedef SRWLOCK NativeHandle;
+#endif
+
+  NativeHandle native_handle_;
+
+  DISALLOW_COPY_AND_ASSIGN(SharedMutex);
+};
 
 // -----------------------------------------------------------------------------
 // LockGuard
@@ -210,22 +269,61 @@ template <typename Mutex, NullBehavior Behavior = NullBehavior::kRequireNotNull>
 class LockGuard final {
  public:
   explicit LockGuard(Mutex* mutex) : mutex_(mutex) {
-    if (Behavior == NullBehavior::kRequireNotNull || mutex_ != nullptr) {
-      mutex_->Lock();
-    }
+    if (has_mutex()) mutex_->Lock();
   }
   ~LockGuard() {
-    if (mutex_ != nullptr) mutex_->Unlock();
+    if (has_mutex()) mutex_->Unlock();
   }
 
  private:
-  Mutex* mutex_;
+  Mutex* const mutex_;
+
+  bool V8_INLINE has_mutex() const {
+    DCHECK_IMPLIES(Behavior == NullBehavior::kRequireNotNull,
+                   mutex_ != nullptr);
+    return Behavior == NullBehavior::kRequireNotNull || mutex_ != nullptr;
+  }
 
   DISALLOW_COPY_AND_ASSIGN(LockGuard);
 };
 
 using MutexGuard = LockGuard<Mutex>;
 
+enum MutexSharedType : bool { kShared = true, kExclusive = false };
+
+template <MutexSharedType kIsShared,
+          NullBehavior Behavior = NullBehavior::kRequireNotNull>
+class SharedMutexGuard final {
+ public:
+  explicit SharedMutexGuard(SharedMutex* mutex) : mutex_(mutex) {
+    if (!has_mutex()) return;
+    if (kIsShared) {
+      mutex_->LockShared();
+    } else {
+      mutex_->LockExclusive();
+    }
+  }
+  ~SharedMutexGuard() {
+    if (!has_mutex()) return;
+    if (kIsShared) {
+      mutex_->UnlockShared();
+    } else {
+      mutex_->UnlockExclusive();
+    }
+  }
+
+ private:
+  SharedMutex* const mutex_;
+
+  bool V8_INLINE has_mutex() const {
+    DCHECK_IMPLIES(Behavior == NullBehavior::kRequireNotNull,
+                   mutex_ != nullptr);
+    return Behavior == NullBehavior::kRequireNotNull || mutex_ != nullptr;
+  }
+
+  DISALLOW_COPY_AND_ASSIGN(SharedMutexGuard);
+};
+
 }  // namespace base
 }  // namespace v8
 
diff --git a/deps/v8/src/base/platform/platform-fuchsia.cc b/deps/v8/src/base/platform/platform-fuchsia.cc
index f6123437ec..7dd29dc39e 100644
--- a/deps/v8/src/base/platform/platform-fuchsia.cc
+++ b/deps/v8/src/base/platform/platform-fuchsia.cc
@@ -20,14 +20,13 @@ uint32_t GetProtectionFromMemoryPermission(OS::MemoryPermission access) {
     case OS::MemoryPermission::kNoAccess:
       return 0;  // no permissions
     case OS::MemoryPermission::kRead:
-      return ZX_VM_FLAG_PERM_READ;
+      return ZX_VM_PERM_READ;
     case OS::MemoryPermission::kReadWrite:
-      return ZX_VM_FLAG_PERM_READ | ZX_VM_FLAG_PERM_WRITE;
+      return ZX_VM_PERM_READ | ZX_VM_PERM_WRITE;
     case OS::MemoryPermission::kReadWriteExecute:
-      return ZX_VM_FLAG_PERM_READ | ZX_VM_FLAG_PERM_WRITE |
-             ZX_VM_FLAG_PERM_EXECUTE;
+      return ZX_VM_PERM_READ | ZX_VM_PERM_WRITE | ZX_VM_PERM_EXECUTE;
     case OS::MemoryPermission::kReadExecute:
-      return ZX_VM_FLAG_PERM_READ | ZX_VM_FLAG_PERM_EXECUTE;
+      return ZX_VM_PERM_READ | ZX_VM_PERM_EXECUTE;
   }
   UNREACHABLE();
 }
@@ -55,13 +54,17 @@ void* OS::Allocate(void* address, size_t size, size_t alignment,
   static const char kVirtualMemoryName[] = "v8-virtualmem";
   zx_object_set_property(vmo, ZX_PROP_NAME, kVirtualMemoryName,
                          strlen(kVirtualMemoryName));
+
+  // Always call zx_vmo_replace_as_executable() in case the memory will need
+  // to be marked as executable in the future.
+  // TOOD(https://crbug.com/v8/8899): Only call this when we know that the
+  // region will need to be marked as executable in the future.
+  if (zx_vmo_replace_as_executable(vmo, ZX_HANDLE_INVALID, &vmo) != ZX_OK) {
+    return nullptr;
+  }
+
   uintptr_t reservation;
   uint32_t prot = GetProtectionFromMemoryPermission(access);
-  if ((prot & ZX_VM_FLAG_PERM_EXECUTE) != 0) {
-    if (zx_vmo_replace_as_executable(vmo, ZX_HANDLE_INVALID, &vmo) != ZX_OK) {
-      return nullptr;
-    }
-  }
   zx_status_t status = zx_vmar_map(zx_vmar_root_self(), prot, 0, vmo, 0,
                                    request_size, &reservation);
   // Either the vmo is now referenced by the vmar, or we failed and are bailing,
diff --git a/deps/v8/src/base/platform/platform-posix.cc b/deps/v8/src/base/platform/platform-posix.cc
index e7edbf5f58..33a9371a92 100644
--- a/deps/v8/src/base/platform/platform-posix.cc
+++ b/deps/v8/src/base/platform/platform-posix.cc
@@ -93,7 +93,7 @@ bool g_hard_abort = false;
 const char* g_gc_fake_mmap = nullptr;
 
 DEFINE_LAZY_LEAKY_OBJECT_GETTER(RandomNumberGenerator,
-                                GetPlatformRandomNumberGenerator);
+                                GetPlatformRandomNumberGenerator)
 static LazyMutex rng_mutex = LAZY_MUTEX_INITIALIZER;
 
 #if !V8_OS_FUCHSIA
@@ -269,7 +269,7 @@ void* OS::GetRandomMmapAddr() {
   return reinterpret_cast<void*>(raw_addr);
 }
 
-// TODO(bbudge) Move Cygwin and Fuschia stuff into platform-specific files.
+// TODO(bbudge) Move Cygwin and Fuchsia stuff into platform-specific files.
 #if !V8_OS_CYGWIN && !V8_OS_FUCHSIA
 // static
 void* OS::Allocate(void* address, size_t size, size_t alignment,
diff --git a/deps/v8/src/base/platform/platform-posix.h b/deps/v8/src/base/platform/platform-posix.h
index 8cf5e54604..7d732b4a8f 100644
--- a/deps/v8/src/base/platform/platform-posix.h
+++ b/deps/v8/src/base/platform/platform-posix.h
@@ -14,7 +14,7 @@ namespace base {
 class PosixTimezoneCache : public TimezoneCache {
  public:
   double DaylightSavingsOffset(double time_ms) override;
-  void Clear() override {}
+  void Clear(TimeZoneDetection) override {}
   ~PosixTimezoneCache() override = default;
 
  protected:
diff --git a/deps/v8/src/base/platform/platform-win32.cc b/deps/v8/src/base/platform/platform-win32.cc
index 45aabf390f..c82ec5335a 100644
--- a/deps/v8/src/base/platform/platform-win32.cc
+++ b/deps/v8/src/base/platform/platform-win32.cc
@@ -113,7 +113,7 @@ class WindowsTimezoneCache : public TimezoneCache {
 
   ~WindowsTimezoneCache() override {}
 
-  void Clear() override { initialized_ = false; }
+  void Clear(TimeZoneDetection) override { initialized_ = false; }
 
   const char* LocalTimezone(double time) override;
 
@@ -690,7 +690,7 @@ void OS::StrNCpy(char* dest, int length, const char* src, size_t n) {
 #undef STRUNCATE
 
 DEFINE_LAZY_LEAKY_OBJECT_GETTER(RandomNumberGenerator,
-                                GetPlatformRandomNumberGenerator);
+                                GetPlatformRandomNumberGenerator)
 static LazyMutex rng_mutex = LAZY_MUTEX_INITIALIZER;
 
 void OS::Initialize(bool hard_abort, const char* const gc_fake_mmap) {
@@ -920,6 +920,11 @@ void OS::Sleep(TimeDelta interval) {
 
 
 void OS::Abort() {
+  // Give a chance to debug the failure.
+  if (IsDebuggerPresent()) {
+    DebugBreak();
+  }
+
   // Before aborting, make sure to flush output buffers.
   fflush(stdout);
   fflush(stderr);
diff --git a/deps/v8/src/base/platform/time.cc b/deps/v8/src/base/platform/time.cc
index 2e10f539f4..5339e14ade 100644
--- a/deps/v8/src/base/platform/time.cc
+++ b/deps/v8/src/base/platform/time.cc
@@ -314,8 +314,8 @@ class Clock final {
 };
 
 namespace {
-DEFINE_LAZY_LEAKY_OBJECT_GETTER(Clock, GetClock);
-};
+DEFINE_LAZY_LEAKY_OBJECT_GETTER(Clock, GetClock)
+}
 
 Time Time::Now() { return GetClock()->Now(); }
 
diff --git a/deps/v8/src/base/small-vector.h b/deps/v8/src/base/small-vector.h
index 5138e65ab5..bbfe2e2e9c 100644
--- a/deps/v8/src/base/small-vector.h
+++ b/deps/v8/src/base/small-vector.h
@@ -15,7 +15,7 @@ namespace base {
 
 // Minimal SmallVector implementation. Uses inline storage first, switches to
 // malloc when it overflows.
-template <typename T, size_t kInlineSize>
+template <typename T, size_t kSize>
 class SmallVector {
   // Currently only support trivially copyable and trivially destructible data
   // types, as it uses memcpy to copy elements and never calls destructors.
@@ -23,6 +23,8 @@ class SmallVector {
   STATIC_ASSERT(std::is_trivially_destructible<T>::value);
 
  public:
+  static constexpr size_t kInlineSize = kSize;
+
   SmallVector() = default;
   SmallVector(const SmallVector& other) V8_NOEXCEPT { *this = other; }
   SmallVector(SmallVector&& other) V8_NOEXCEPT { *this = std::move(other); }
@@ -62,9 +64,15 @@ class SmallVector {
     return *this;
   }
 
-  T* data() const { return begin_; }
-  T* begin() const { return begin_; }
-  T* end() const { return end_; }
+  T* data() { return begin_; }
+  const T* data() const { return begin_; }
+
+  T* begin() { return begin_; }
+  const T* begin() const { return begin_; }
+
+  T* end() { return end_; }
+  const T* end() const { return end_; }
+
   size_t size() const { return end_ - begin_; }
   bool empty() const { return end_ == begin_; }
   size_t capacity() const { return end_of_storage_ - begin_; }
diff --git a/deps/v8/src/base/timezone-cache.h b/deps/v8/src/base/timezone-cache.h
index 3d97eee126..5b8e5a20da 100644
--- a/deps/v8/src/base/timezone-cache.h
+++ b/deps/v8/src/base/timezone-cache.h
@@ -23,8 +23,22 @@ class TimezoneCache {
   // https://github.com/tc39/ecma262/pull/778
   virtual double LocalTimeOffset(double time_ms, bool is_utc) = 0;
 
+  /**
+   * Time zone redetection indicator for Clear function.
+   *
+   * kSkip indicates host time zone doesn't have to be redetected.
+   * kRedetect indicates host time zone should be redetected, and used to set
+   * the default time zone.
+   *
+   * The host time zone detection may require file system access or similar
+   * operations unlikely to be available inside a sandbox. If v8 is run inside a
+   * sandbox, the host time zone has to be detected outside the sandbox
+   * separately.
+   */
+  enum class TimeZoneDetection { kSkip, kRedetect };
+
   // Called when the local timezone changes
-  virtual void Clear() = 0;
+  virtual void Clear(TimeZoneDetection time_zone_detection) = 0;
 
   // Called when tearing down the isolate
   virtual ~TimezoneCache() = default;