Remove dependency from platform.h implementations on isolate

BUG=none
R=bmeurer@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/347223004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21997 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/platform-posix.cc

@@ -43,8 +43,9 @@
 
 #include "src/v8.h"
 
-#include "src/isolate-inl.h"
+#include "src/base/lazy-instance.h"
 #include "src/platform.h"
+#include "src/utils/random-number-generator.h"
 
 #ifdef V8_FAST_TLS_SUPPORTED
 #include "src/base/atomicops.h"
@@ -186,6 +187,15 @@ void OS::Guard(void* address, const size_t size) {
 }
 
 
+static base::LazyInstance<RandomNumberGenerator>::type
+    platform_random_number_generator = LAZY_INSTANCE_INITIALIZER;
+
+
+void OS::SetRandomSeed(int64_t seed) {
+  platform_random_number_generator.Pointer()->SetSeed(seed);
+}
+
+
 void* OS::GetRandomMmapAddr() {
 #if V8_OS_NACL
   // TODO(bradchen): restore randomization once Native Client gets
@@ -198,13 +208,9 @@ void* OS::GetRandomMmapAddr() {
   // Dynamic tools do not support custom mmap addresses.
   return NULL;
 #endif
-  Isolate* isolate = Isolate::UncheckedCurrent();
-  // Note that the current isolate isn't set up in a call path via
-  // CpuFeatures::Probe. We don't care about randomization in this case because
-  // the code page is immediately freed.
-  if (isolate != NULL) {
   uintptr_t raw_addr;
-    isolate->random_number_generator()->NextBytes(&raw_addr, sizeof(raw_addr));
+  platform_random_number_generator.Pointer()->NextBytes(&raw_addr,
+                                                        sizeof(raw_addr));
 #if V8_TARGET_ARCH_X64
   // Currently available CPUs have 48 bits of virtual addressing.  Truncate
   // the hint address to 46 bits to give the kernel a fighting chance of
@@ -232,8 +238,6 @@ void* OS::GetRandomMmapAddr() {
 # endif
 #endif
   return reinterpret_cast<void*>(raw_addr);
-  }
-  return NULL;
 }
 
 

src/platform-win32.cc

@@ -19,8 +19,9 @@
 
 #include "src/v8.h"
 
-#include "src/isolate-inl.h"
+#include "src/base/lazy-instance.h"
 #include "src/platform.h"
+#include "src/utils/random-number-generator.h"
 
 #ifdef _MSC_VER
 
@@ -708,12 +709,16 @@ size_t OS::AllocateAlignment() {
 }
 
 
+static base::LazyInstance<RandomNumberGenerator>::type
+    platform_random_number_generator = LAZY_INSTANCE_INITIALIZER;
+
+
+void OS::SetRandomSeed(int64_t seed) {
+  platform_random_number_generator.Pointer()->SetSeed(seed);
+}
+
+
 void* OS::GetRandomMmapAddr() {
-  Isolate* isolate = Isolate::UncheckedCurrent();
-  // Note that the current isolate isn't set up in a call path via
-  // CpuFeatures::Probe. We don't care about randomization in this case because
-  // the code page is immediately freed.
-  if (isolate != NULL) {
   // The address range used to randomize RWX allocations in OS::Allocate
   // Try not to map pages into the default range that windows loads DLLs
   // Use a multiple of 64k to prevent committing unused memory.
@@ -727,12 +732,10 @@ void* OS::GetRandomMmapAddr() {
   static const intptr_t kAllocationRandomAddressMax = 0x3FFF0000;
 #endif
   uintptr_t address =
-        (isolate->random_number_generator()->NextInt() << kPageSizeBits) |
+      (platform_random_number_generator.Pointer()->NextInt() << kPageSizeBits) |
       kAllocationRandomAddressMin;
   address &= kAllocationRandomAddressMax;
   return reinterpret_cast<void *>(address);
-  }
-  return NULL;
 }
 
 

src/platform.h

@@ -212,6 +212,10 @@ class OS {
   // Assign memory as a guard page so that access will cause an exception.
   static void Guard(void* address, const size_t size);
 
+  // Set a fixed random seed for the random number generator used for
+  // GetRandomMmapAddr.
+  static void SetRandomSeed(int64_t seed);
+
   // Generate a random address to be used for hinting mmap().
   static void* GetRandomMmapAddr();
 

src/utils/random-number-generator.h

@@ -71,13 +71,15 @@ class RandomNumberGenerator V8_FINAL {
   // Fills the elements of a specified array of bytes with random numbers.
   void NextBytes(void* buffer, size_t buflen);
 
+  // Override the current ssed.
+  void SetSeed(int64_t seed);
+
  private:
   static const int64_t kMultiplier = V8_2PART_UINT64_C(0x5, deece66d);
   static const int64_t kAddend = 0xb;
   static const int64_t kMask = V8_2PART_UINT64_C(0xffff, ffffffff);
 
   int Next(int bits) V8_WARN_UNUSED_RESULT;
-  void SetSeed(int64_t seed);
 
   int64_t seed_;
 };

src/v8.cc

@@ -90,6 +90,8 @@ void V8::InitializeOncePerProcessImpl() {
     FLAG_max_semi_space_size = 1;
   }
 
+  if (FLAG_random_seed != 0) OS::SetRandomSeed(FLAG_random_seed);
+
 #ifdef V8_USE_DEFAULT_PLATFORM
   platform_ = new DefaultPlatform;
 #endif