deps: cherry-pick c736883 from upstream V8

Original commit message:

    Optionally use halfsiphash for integer hashing.

    Change-Id: Ibd14f7b3fe78635675c76ae864112e3a3a7bc701
    Reviewed-on: https://chromium-review.googlesource.com/c/1382463
    Commit-Queue: Yang Guo <yangguo@chromium.org>
    Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
    Cr-Commit-Position: refs/heads/master@{#58674}

Refs: https://github.com/v8/v8/commit/c736883ed4e3ff92d1fd5a60497cec5311df9a25

8 files changed, 308 insertions, 2 deletions

diff --git a/deps/v8/BUILD.gn b/deps/v8/BUILD.gn
index 6bb77db7ea..10e1a28b0a 100644
--- a/deps/v8/BUILD.gn
+++ b/deps/v8/BUILD.gn
@@ -116,6 +116,9 @@ declare_args() {
   # tools/gen-postmortem-metadata.py for details.
   v8_postmortem_support = false
 
+  # Use Siphash as added protection against hash flooding attacks.
+  v8_use_siphash = false
+
   # Switches off inlining in V8.
   v8_no_inline = false
 
@@ -390,6 +393,9 @@ config("features") {
   if (v8_use_multi_snapshots) {
     defines += [ "V8_MULTI_SNAPSHOTS" ]
   }
+  if (v8_use_siphash) {
+    defines += [ "V8_USE_SIPHASH" ]
+  }
 }
 
 config("toolchain") {
@@ -2502,6 +2508,8 @@ v8_source_set("v8_base") {
     "src/string-stream.h",
     "src/strtod.cc",
     "src/strtod.h",
+    "src/third_party/siphash/halfsiphash.cc",
+    "src/third_party/siphash/halfsiphash.h",
     "src/third_party/utf8-decoder/utf8-decoder.h",
     "src/torque-assembler.h",
     "src/tracing/trace-event.cc",
diff --git a/deps/v8/PRESUBMIT.py b/deps/v8/PRESUBMIT.py
index 88a64e727b..e48d51d8e5 100644
--- a/deps/v8/PRESUBMIT.py
+++ b/deps/v8/PRESUBMIT.py
@@ -43,6 +43,9 @@ _EXCLUDED_PATHS = (
     r"^tools[\\\/].*",
 )
 
+_LICENSE_FILE = (
+    r"LICENSE"
+)
 
 # Regular expression that matches code which should not be run through cpplint.
 _NO_LINT_PATHS = (
@@ -311,8 +314,13 @@ def _CommonChecks(input_api, output_api):
   results.extend(_CheckCommitMessageBugEntry(input_api, output_api))
   results.extend(input_api.canned_checks.CheckPatchFormatted(
       input_api, output_api))
+
+  # License files are taken as is, even if they include gendered pronouns.
+  license_filter = lambda path: input_api.FilterSourceFile(
+      path, black_list=_LICENSE_FILE)
   results.extend(input_api.canned_checks.CheckGenderNeutral(
-      input_api, output_api))
+      input_api, output_api, source_file_filter=license_filter))
+
   results.extend(_V8PresubmitChecks(input_api, output_api))
   results.extend(_CheckUnwantedDependencies(input_api, output_api))
   results.extend(
diff --git a/deps/v8/src/third_party/siphash/LICENSE b/deps/v8/src/third_party/siphash/LICENSE
new file mode 100644
index 0000000000..670154e353
--- /dev/null
+++ b/deps/v8/src/third_party/siphash/LICENSE
@@ -0,0 +1,116 @@
+CC0 1.0 Universal
+
+Statement of Purpose
+
+The laws of most jurisdictions throughout the world automatically confer
+exclusive Copyright and Related Rights (defined below) upon the creator and
+subsequent owner(s) (each and all, an "owner") of an original work of
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+Certain owners wish to permanently relinquish those rights to a Work for the
+purpose of contributing to a commons of creative, cultural and scientific
+works ("Commons") that the public can reliably and without fear of later
+claims of infringement build upon, modify, incorporate in other works, reuse
+and redistribute as freely as possible in any form whatsoever and for any
+purposes, including without limitation commercial purposes. These owners may
+contribute to the Commons to promote the ideal of a free culture and the
+further production of creative, cultural and scientific works, or to gain
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+of additional consideration or compensation, the person associating CC0 with a
+Work (the "Affirmer"), to the extent that he or she is an owner of Copyright
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+1. Copyright and Related Rights. A Work made available under CC0 may be
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diff --git a/deps/v8/src/third_party/siphash/halfsiphash.cc b/deps/v8/src/third_party/siphash/halfsiphash.cc
new file mode 100644
index 0000000000..d3730c4819
--- /dev/null
+++ b/deps/v8/src/third_party/siphash/halfsiphash.cc
@@ -0,0 +1,83 @@
+/*
+ * SipHash reference C implementation
+ *
+ * Copyright (c) 2016 Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>
+ *
+ * To the extent possible under law, the author(s) have dedicated all
+ * copyright and related and neighboring rights to this software to the public
+ * domain worldwide. This software is distributed without any warranty.
+ *
+ * You should have received a copy of the CC0 Public Domain Dedication along
+ * with this software. If not, see
+ * <http://creativecommons.org/publicdomain/zero/1.0/>.
+ */
+
+/*
+ * Originally taken from https://github.com/veorq/SipHash/
+ * Altered to match V8's use case.
+ */
+
+#include <stdint.h>
+
+#include "src/base/logging.h"
+#include "src/base/v8-fallthrough.h"
+
+#define ROTL(x, b) (uint32_t)(((x) << (b)) | ((x) >> (32 - (b))))
+
+#define SIPROUND       \
+  do {                 \
+    v0 += v1;          \
+    v1 = ROTL(v1, 5);  \
+    v1 ^= v0;          \
+    v0 = ROTL(v0, 16); \
+    v2 += v3;          \
+    v3 = ROTL(v3, 8);  \
+    v3 ^= v2;          \
+    v0 += v3;          \
+    v3 = ROTL(v3, 7);  \
+    v3 ^= v0;          \
+    v2 += v1;          \
+    v1 = ROTL(v1, 13); \
+    v1 ^= v2;          \
+    v2 = ROTL(v2, 16); \
+  } while (0)
+
+// Simplified half-siphash-2-4 implementation for 4 byte input.
+uint32_t halfsiphash(const uint32_t value, const uint64_t seed) {
+  uint32_t v0 = 0;
+  uint32_t v1 = 0;
+  uint32_t v2 = 0x6c796765;
+  uint32_t v3 = 0x74656462;
+  uint32_t k[2];
+  memcpy(k, &seed, sizeof(seed));
+  uint32_t b = 4 << 24;
+  v3 ^= k[1];
+  v2 ^= k[0];
+  v1 ^= k[1];
+  v0 ^= k[0];
+
+  v3 ^= value;
+
+  // 2 c-rounds
+  SIPROUND;
+  SIPROUND;
+
+  v0 ^= value;
+  v3 ^= b;
+
+  // 2 c-rounds
+  SIPROUND;
+  SIPROUND;
+
+  v0 ^= b;
+  v2 ^= 0xff;
+
+  // 4 d-rounds
+  SIPROUND;
+  SIPROUND;
+  SIPROUND;
+  SIPROUND;
+
+  b = v1 ^ v3;
+  return b;
+}
diff --git a/deps/v8/src/third_party/siphash/halfsiphash.h b/deps/v8/src/third_party/siphash/halfsiphash.h
new file mode 100644
index 0000000000..7b55115774
--- /dev/null
+++ b/deps/v8/src/third_party/siphash/halfsiphash.h
@@ -0,0 +1,17 @@
+/*
+ * SipHash reference C implementation
+ *
+ * Copyright (c) 2016 Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>
+ *
+ * To the extent possible under law, the author(s) have dedicated all
+ * copyright and related and neighboring rights to this software to the public
+ * domain worldwide. This software is distributed without any warranty.
+ *
+ * You should have received a copy of the CC0 Public Domain Dedication along
+ * with this software. If not, see
+ * <http://creativecommons.org/publicdomain/zero/1.0/>.
+ */
+
+#include <cstdint>
+
+uint32_t halfsiphash(const uint32_t value, const uint64_t seed);
diff --git a/deps/v8/src/utils.h b/deps/v8/src/utils.h
index 90a1227a2b..51c22ffd70 100644
--- a/deps/v8/src/utils.h
+++ b/deps/v8/src/utils.h
@@ -22,6 +22,7 @@
 #include "src/base/platform/platform.h"
 #include "src/base/v8-fallthrough.h"
 #include "src/globals.h"
+#include "src/third_party/siphash/halfsiphash.h"
 #include "src/vector.h"
 
 #if defined(V8_OS_AIX)
@@ -513,7 +514,11 @@ inline uint32_t ComputeLongHash(uint64_t key) {
 }
 
 inline uint32_t ComputeSeededHash(uint32_t key, uint64_t seed) {
+#ifdef V8_USE_SIPHASH
+  return halfsiphash(key, seed);
+#else
   return ComputeLongHash(static_cast<uint64_t>(key) ^ seed);
+#endif  // V8_USE_SIPHASH
 }
 
 inline uint32_t ComputePointerHash(void* ptr) {
diff --git a/deps/v8/test/cctest/test-code-stub-assembler.cc b/deps/v8/test/cctest/test-code-stub-assembler.cc
index ffe9200eee..4289efa1d0 100644
--- a/deps/v8/test/cctest/test-code-stub-assembler.cc
+++ b/deps/v8/test/cctest/test-code-stub-assembler.cc
@@ -345,7 +345,7 @@ TEST(ComputeIntegerHash) {
     Handle<Object> result = ft.Call(key).ToHandleChecked();
 
     uint32_t hash = ComputeSeededHash(k, isolate->heap()->HashSeed());
-    Smi* expected = Smi::FromInt(hash & Smi::kMaxValue);
+    Smi* expected = Smi::FromInt(hash);
     CHECK_EQ(expected, Smi::cast(*result));
   }
 }
diff --git a/deps/v8/test/cctest/test-hashcode.cc b/deps/v8/test/cctest/test-hashcode.cc
index 2059d53885..7c07ff6fdc 100644
--- a/deps/v8/test/cctest/test-hashcode.cc
+++ b/deps/v8/test/cctest/test-hashcode.cc
@@ -8,6 +8,8 @@
 
 #include "src/objects-inl.h"
 #include "src/objects.h"
+#include "src/third_party/siphash/halfsiphash.h"
+#include "src/utils.h"
 #include "src/v8.h"
 
 #include "test/cctest/cctest.h"
@@ -227,5 +229,72 @@ TEST(TransitionSlowToFastWithPropertyArray) {
   CheckFastObject(obj, hash);
 }
 
+namespace {
+
+typedef uint32_t (*HashFunction)(uint32_t key, uint64_t seed);
+
+void TestIntegerHashQuality(const int samples_log2, int num_buckets_log2,
+                            uint64_t seed, double max_var,
+                            HashFunction hash_function) {
+  int samples = 1 << samples_log2;
+  int num_buckets = 1 << num_buckets_log2;
+  int mean = samples / num_buckets;
+  int* buckets = new int[num_buckets];
+
+  for (int i = 0; i < num_buckets; i++) buckets[i] = 0;
+
+  for (int i = 0; i < samples; i++) {
+    uint32_t hash = hash_function(i, seed);
+    buckets[hash % num_buckets]++;
+  }
+
+  int sum_deviation = 0;
+  for (int i = 0; i < num_buckets; i++) {
+    int deviation = abs(buckets[i] - mean);
+    sum_deviation += deviation * deviation;
+  }
+  delete[] buckets;
+
+  double variation_coefficient = sqrt(sum_deviation * 1.0 / num_buckets) / mean;
+
+  printf("samples: 1 << %2d, buckets: 1 << %2d, var_coeff: %0.3f\n",
+         samples_log2, num_buckets_log2, variation_coefficient);
+  CHECK_LT(variation_coefficient, max_var);
+}
+uint32_t HalfSipHash(uint32_t key, uint64_t seed) {
+  return halfsiphash(key, seed);
+}
+
+uint32_t JenkinsHash(uint32_t key, uint64_t seed) {
+  return ComputeLongHash(static_cast<uint64_t>(key) ^ seed);
+}
+
+uint32_t DefaultHash(uint32_t key, uint64_t seed) {
+  return ComputeSeededHash(key, seed);
+}
+}  // anonymous namespace
+
+void TestIntegerHashQuality(HashFunction hash_function) {
+  TestIntegerHashQuality(17, 13, 0x123456789ABCDEFU, 0.4, hash_function);
+  TestIntegerHashQuality(16, 12, 0x123456789ABCDEFU, 0.4, hash_function);
+  TestIntegerHashQuality(15, 11, 0xFEDCBA987654321U, 0.4, hash_function);
+  TestIntegerHashQuality(14, 10, 0xFEDCBA987654321U, 0.4, hash_function);
+  TestIntegerHashQuality(13, 9, 1, 0.4, hash_function);
+  TestIntegerHashQuality(12, 8, 1, 0.4, hash_function);
+
+  TestIntegerHashQuality(17, 10, 0x123456789ABCDEFU, 0.2, hash_function);
+  TestIntegerHashQuality(16, 9, 0x123456789ABCDEFU, 0.2, hash_function);
+  TestIntegerHashQuality(15, 8, 0xFEDCBA987654321U, 0.2, hash_function);
+  TestIntegerHashQuality(14, 7, 0xFEDCBA987654321U, 0.2, hash_function);
+  TestIntegerHashQuality(13, 6, 1, 0.2, hash_function);
+  TestIntegerHashQuality(12, 5, 1, 0.2, hash_function);
+}
+
+TEST(HalfSipHashQuality) { TestIntegerHashQuality(HalfSipHash); }
+
+TEST(JenkinsHashQuality) { TestIntegerHashQuality(JenkinsHash); }
+
+TEST(DefaultHashQuality) { TestIntegerHashQuality(DefaultHash); }
+
 }  // namespace internal
 }  // namespace v8