Fix leakage of virtual address space on Linux platform.

src/platform-linux.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 459 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() {
   // This function assumes that the layout of the file is as follows:
   // hex_start_addr-hex_end_addr rwxp <unused data> [binary_file_name]
   // If we encounter an unexpected situation we abort scanning further entries.
   FILE* fp = fopen("/proc/self/maps", "r");
   if (fp == NULL) return;
@@ skipping 61 matching lines @@
   // PROT_EXEC so that analysis tools can properly attribute ticks. We
   // do a mmap with a name known by ll_prof.py and immediately munmap
   // it. This injects a GC marker into the stream of events generated
   // by the kernel and allows us to synchronize V8 code log and the
   // kernel log.
   int size = sysconf(_SC_PAGESIZE);
   FILE* f = fopen(kGCFakeMmap, "w+");
   void* addr = mmap(NULL, size, PROT_READ | PROT_EXEC, MAP_PRIVATE,
                     fileno(f), 0);
   ASSERT(addr != MAP_FAILED);
-  munmap(addr, size);
+  OS::Free(addr, size);
   fclose(f);
 }
 
 
 int OS::StackWalk(Vector<OS::StackFrame> frames) {
   // backtrace is a glibc extension.
 #ifdef __GLIBC__
   int frames_size = frames.length();
   ScopedVector<void*> addresses(frames_size);
 
@@ skipping 41 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(GetRandomMmapAddr(),
                            request_size,
                            PROT_NONE,
                            MAP_PRIVATE | MAP_ANONYMOUS | 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 563 matching lines @@
 
 
 void Sampler::Stop() {
   ASSERT(IsActive());
   SignalSender::RemoveActiveSampler(this);
   SetActive(false);
 }
 
 
 } }  // namespace v8::internal