Fix leakage of virtual address space on Linux platform.

src/platform-macos.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 210 matching lines @@
     fclose(file);
     return NULL;
   }
   void* memory =
       mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fileno(file), 0);
   return new PosixMemoryMappedFile(file, memory, size);
 }
 
 
 PosixMemoryMappedFile::~PosixMemoryMappedFile() {
-  if (memory_) munmap(memory_, size_);
+  if (memory_) OS::Free(memory_, size_);
   fclose(file_);
 }
 
 
 void OS::LogSharedLibraryAddresses() {
   unsigned int images_count = _dyld_image_count();
   for (unsigned int i = 0; i < images_count; ++i) {
     const mach_header* header = _dyld_get_image_header(i);
     if (header == NULL) continue;
 #if V8_HOST_ARCH_X64
@@ skipping 104 matching lines @@
   ASSERT(IsAligned(alignment, static_cast<intptr_t>(OS::AllocateAlignment())));
   size_t request_size = RoundUp(size + alignment,
                                 static_cast<intptr_t>(OS::AllocateAlignment()));
   void* reservation = mmap(NULL,
                            request_size,
                            PROT_NONE,
                            MAP_PRIVATE | MAP_ANON | MAP_NORESERVE,
                            kMmapFd,
                            kMmapFdOffset);
   if (reservation == MAP_FAILED) return;
+
   Address base = static_cast<Address>(reservation);
   Address aligned_base = RoundUp(base, alignment);
-  ASSERT(base <= aligned_base);
+  ASSERT_LE(base, aligned_base);
 
   // Unmap extra memory reserved before and after the desired block.
-  size_t bytes_prior = static_cast<size_t>(aligned_base - base);
-  if (bytes_prior > 0) {
-    munmap(base, bytes_prior);
-  }
-  if (static_cast<size_t>(aligned_base - base) < request_size - size) {
-    munmap(aligned_base + size, request_size - size - bytes_prior);
+  if (aligned_base != base) {
+    size_t prefix_size = static_cast<size_t>(aligned_base - base);
+    OS::Free(base, prefix_size);
+    request_size -= prefix_size;
   }
 
+  size_t aligned_size = RoundUp(size, OS::AllocateAlignment());
+  ASSERT_LE(aligned_size, request_size);
+
+  if (aligned_size != request_size) {
+    size_t suffix_size = request_size - aligned_size;
+    OS::Free(aligned_base + aligned_size, suffix_size);
+    request_size -= suffix_size;
+  }
+
+  ASSERT(aligned_size == request_size);
+
   address_ = static_cast<void*>(aligned_base);
-  size_ = size;
+  size_ = aligned_size;
 }
 
 
 VirtualMemory::~VirtualMemory() {
   if (IsReserved()) {
     bool result = ReleaseRegion(address(), size());
     ASSERT(result);
     USE(result);
   }
 }
@@ skipping 488 matching lines @@
 
 
 void Sampler::Stop() {
   ASSERT(IsActive());
   SamplerThread::RemoveActiveSampler(this);
   SetActive(false);
 }
 
 
 } }  // namespace v8::internal