Improve reproducibility of test runs.

Add random seed to run-tests.py, using either a user supplied
value or a random number generated by random.SystemRandom().
This same random seed is passed to all test cases, making sure
that we can easily reproduce test failures that depend on
random numbers (i.e. bugs related to our handwritten ASLR).

Also fix all uses of rand() to make use of our RNG class
instead.

R=machenbach@chromium.org

Review URL: https://codereview.chromium.org/231443002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@20637 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

test/cctest/test-strtod.cc

@@ -34,6 +34,7 @@
 #include "diy-fp.h"
 #include "double.h"
 #include "strtod.h"
+#include "utils/random-number-generator.h"
 
 using namespace v8::internal;
 
@@ -448,13 +449,13 @@ static const int kShortStrtodRandomCount = 2;
 static const int kLargeStrtodRandomCount = 2;
 
 TEST(RandomStrtod) {
-  srand(static_cast<unsigned int>(time(NULL)));
+  RandomNumberGenerator rng;
   char buffer[kBufferSize];
   for (int length = 1; length < 15; length++) {
     for (int i = 0; i < kShortStrtodRandomCount; ++i) {
       int pos = 0;
       for (int j = 0; j < length; ++j) {
-        buffer[pos++] = rand() % 10 + '0';
+        buffer[pos++] = rng.NextInt(10) + '0';
       }
       int exponent = DeterministicRandom() % (25*2 + 1) - 25 - length;
       buffer[pos] = '\0';
@@ -467,7 +468,7 @@ TEST(RandomStrtod) {
     for (int i = 0; i < kLargeStrtodRandomCount; ++i) {
       int pos = 0;
       for (int j = 0; j < length; ++j) {
-        buffer[pos++] = rand() % 10 + '0';
+        buffer[pos++] = rng.NextInt(10) + '0';
       }
       int exponent = DeterministicRandom() % (308*2 + 1) - 308 - length;
       buffer[pos] = '\0';

test/cctest/test-types.cc

@@ -29,6 +29,7 @@
 
 #include "cctest.h"
 #include "types.h"
+#include "utils/random-number-generator.h"
 
 using namespace v8::internal;
 
@@ -112,6 +113,8 @@ class Types {
     objects.push_back(array);
   }
 
+  RandomNumberGenerator rng;
+
   TypeHandle Representation;
   TypeHandle Semantic;
   TypeHandle None;
@@ -180,14 +183,14 @@ class Types {
   }
 
   TypeHandle Fuzz(int depth = 5) {
-    switch (rand() % (depth == 0 ? 3 : 20)) {
+    switch (rng.NextInt(depth == 0 ? 3 : 20)) {
       case 0: {  // bitset
         int n = 0
         #define COUNT_BITSET_TYPES(type, value) + 1
         BITSET_TYPE_LIST(COUNT_BITSET_TYPES)
         #undef COUNT_BITSET_TYPES
         ;
-        int i = rand() % n;
+        int i = rng.NextInt(n);
         #define PICK_BITSET_TYPE(type, value) \
           if (i-- == 0) return Type::type(region_);
         BITSET_TYPE_LIST(PICK_BITSET_TYPE)
@@ -195,13 +198,13 @@ class Types {
         UNREACHABLE();
       }
       case 1:  // class
-        switch (rand() % 2) {
+        switch (rng.NextInt(2)) {
           case 0: return ObjectClass;
           case 1: return ArrayClass;
         }
         UNREACHABLE();
       case 2:  // constant
-        switch (rand() % 6) {
+        switch (rng.NextInt(6)) {
           case 0: return SmiConstant;
           case 1: return Signed32Constant;
           case 2: return ObjectConstant1;
@@ -211,7 +214,7 @@ class Types {
         }
         UNREACHABLE();
       default: {  // union
-        int n = rand() % 10;
+        int n = rng.NextInt(10);
         TypeHandle type = None;
         for (int i = 0; i < n; ++i) {
           type = Type::Union(type, Fuzz(depth - 1), region_);

test/mjsunit/mjsunit.status

@@ -93,7 +93,11 @@
   # This test sets the umask on a per-process basis and hence cannot be
   # used in multi-threaded runs.
   # On android there is no /tmp directory.
-  'd8-os': [PASS, ['isolates or arch == android_arm or arch == android_arm64 or arch == android_ia32', SKIP]],
+  # Currently d8-os generates a temporary directory name using Math.random(), so
+  # we cannot run several variants of d8-os simultaneously, since all of them
+  # get the same random seed and would generate the same directory name. Besides
+  # that, it doesn't make sense to run several variants of d8-os anyways.
+  'd8-os': [PASS, NO_VARIANTS, ['isolates or arch == android_arm or arch == android_arm64 or arch == android_ia32', SKIP]],
   'tools/tickprocessor': [PASS, ['arch == android_arm or arch == android_arm64 or arch == android_ia32', SKIP]],
 
   ##############################################################################

tools/run-tests.py

@@ -34,6 +34,7 @@ import optparse
 import os
 from os.path import join
 import platform
+import random
 import shlex
 import subprocess
 import sys
@@ -200,6 +201,8 @@ def BuildOptions():
   result.add_option("--junittestsuite",
                     help="The testsuite name in the JUnit output file",
                     default="v8tests")
+  result.add_option("--random-seed", default=0, dest="random_seed",
+                    help="Default seed for initializing random generator")
   return result
 
 
@@ -250,6 +253,9 @@ def ProcessOptions(options):
   if options.j == 0:
     options.j = multiprocessing.cpu_count()
 
+  while options.random_seed == 0:
+    options.random_seed = random.SystemRandom().randint(-2147483648, 2147483647)
+
   def excl(*args):
     """Returns true if zero or one of multiple arguments are true."""
     return reduce(lambda x, y: x + y, args) <= 1
@@ -396,7 +402,8 @@ def Execute(arch, mode, args, options, suites, workspace):
                         timeout, options.isolates,
                         options.command_prefix,
                         options.extra_flags,
-                        options.no_i18n)
+                        options.no_i18n,
+                        options.random_seed)
 
   # TODO(all): Combine "simulator" and "simulator_run".
   simulator_run = not options.dont_skip_simulator_slow_tests and \

tools/testrunner/local/execution.py

@@ -171,6 +171,7 @@ class Runner(object):
     cmd = (self.context.command_prefix +
            [os.path.abspath(os.path.join(self.context.shell_dir, shell))] +
            d8testflag +
+           ["--random-seed=%s" % self.context.random_seed] +
            test.suite.GetFlagsForTestCase(test, self.context) +
            self.context.extra_flags)
     return cmd

tools/testrunner/objects/context.py

@@ -28,7 +28,7 @@
 
 class Context():
   def __init__(self, arch, mode, shell_dir, mode_flags, verbose, timeout,
-               isolates, command_prefix, extra_flags, noi18n):
+               isolates, command_prefix, extra_flags, noi18n, random_seed):
     self.arch = arch
     self.mode = mode
     self.shell_dir = shell_dir
@@ -39,13 +39,16 @@ class Context():
     self.command_prefix = command_prefix
     self.extra_flags = extra_flags
     self.noi18n = noi18n
+    self.random_seed = random_seed
 
   def Pack(self):
     return [self.arch, self.mode, self.mode_flags, self.timeout, self.isolates,
-            self.command_prefix, self.extra_flags, self.noi18n]
+            self.command_prefix, self.extra_flags, self.noi18n,
+            self.random_seed]
 
   @staticmethod
   def Unpack(packed):
     # For the order of the fields, refer to Pack() above.
     return Context(packed[0], packed[1], None, packed[2], False,
-                   packed[3], packed[4], packed[5], packed[6], packed[7])
+                   packed[3], packed[4], packed[5], packed[6], packed[7],
+                   packed[8])