Remove dependency from platform.h implementations on isolate

src/platform-posix.cc

Index: src/platform-posix.cc
diff --git a/src/platform-posix.cc b/src/platform-posix.cc
index fe3feb52fc8d77a94eb937c8e6f28aa99caa8623..ae47bd4d3fac7467806729160696ecc908598b25 100644
--- a/src/platform-posix.cc
+++ b/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
@@ -198,42 +208,36 @@ 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));
+  uintptr_t 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
-    // fulfilling our placement request.
-    raw_addr &= V8_UINT64_C(0x3ffffffff000);
+  // Currently available CPUs have 48 bits of virtual addressing.  Truncate
+  // the hint address to 46 bits to give the kernel a fighting chance of
+  // fulfilling our placement request.
+  raw_addr &= V8_UINT64_C(0x3ffffffff000);
 #else
-    raw_addr &= 0x3ffff000;
+  raw_addr &= 0x3ffff000;
 
 # ifdef __sun
-    // For our Solaris/illumos mmap hint, we pick a random address in the bottom
-    // half of the top half of the address space (that is, the third quarter).
-    // Because we do not MAP_FIXED, this will be treated only as a hint -- the
-    // system will not fail to mmap() because something else happens to already
-    // be mapped at our random address. We deliberately set the hint high enough
-    // to get well above the system's break (that is, the heap); Solaris and
-    // illumos will try the hint and if that fails allocate as if there were
-    // no hint at all. The high hint prevents the break from getting hemmed in
-    // at low values, ceding half of the address space to the system heap.
-    raw_addr += 0x80000000;
+  // For our Solaris/illumos mmap hint, we pick a random address in the bottom
+  // half of the top half of the address space (that is, the third quarter).
+  // Because we do not MAP_FIXED, this will be treated only as a hint -- the
+  // system will not fail to mmap() because something else happens to already
+  // be mapped at our random address. We deliberately set the hint high enough
+  // to get well above the system's break (that is, the heap); Solaris and
+  // illumos will try the hint and if that fails allocate as if there were
+  // no hint at all. The high hint prevents the break from getting hemmed in
+  // at low values, ceding half of the address space to the system heap.
+  raw_addr += 0x80000000;
 # else
-    // The range 0x20000000 - 0x60000000 is relatively unpopulated across a
-    // variety of ASLR modes (PAE kernel, NX compat mode, etc) and on macos
-    // 10.6 and 10.7.
-    raw_addr += 0x20000000;
+  // The range 0x20000000 - 0x60000000 is relatively unpopulated across a
+  // variety of ASLR modes (PAE kernel, NX compat mode, etc) and on macos
+  // 10.6 and 10.7.
+  raw_addr += 0x20000000;
 # endif
 #endif
-    return reinterpret_cast<void*>(raw_addr);
-  }
-  return NULL;
+  return reinterpret_cast<void*>(raw_addr);
 }