Merge experimental/gc branch to the bleeding_edge.

src/platform-win32.cc

Index: src/platform-win32.cc
===================================================================
--- src/platform-win32.cc	(revision 9327)
+++ src/platform-win32.cc	(working copy)
@@ -1397,41 +1397,99 @@
 }
 
 
+VirtualMemory::VirtualMemory() : address_(NULL), size_(0) { }
+
+
+VirtualMemory::VirtualMemory(size_t size)
+    : address_(ReserveRegion(size)), size_(size) { }
+
+
+VirtualMemory::VirtualMemory(size_t size, size_t alignment)
+    : address_(NULL), size_(0) {
+  ASSERT(IsAligned(alignment, static_cast<intptr_t>(OS::AllocateAlignment())));
+  size_t request_size = RoundUp(size + alignment,
+                                static_cast<intptr_t>(OS::AllocateAlignment()));
+  void* address = ReserveRegion(request_size);
+  if (address == NULL) return;
+  Address base = RoundUp(static_cast<Address>(address), alignment);
+  // Try reducing the size by freeing and then reallocating a specific area.
+  ReleaseRegion(address, request_size);
+  address = VirtualAlloc(base, size, MEM_RESERVE, PAGE_NOACCESS);
+  if (address != NULL) {
+    request_size = size;
+    ASSERT(base == static_cast<Address>(address));
+  } else {
+    // Resizing failed, just go with a bigger area.
+    address = ReserveRegion(request_size);
+    if (address == NULL) return;
+  }
+  address_ = address;
+  size_ = request_size;
+}
+
+
+VirtualMemory::~VirtualMemory() {
+  if (IsReserved()) {
+    bool result = ReleaseRegion(address_, size_);
+    ASSERT(result);
+    USE(result);
+  }
+}
+
+
 bool VirtualMemory::IsReserved() {
   return address_ != NULL;
 }
 
 
-VirtualMemory::VirtualMemory(size_t size) {
-  address_ = VirtualAlloc(NULL, size, MEM_RESERVE, PAGE_NOACCESS);
-  size_ = size;
+void VirtualMemory::Reset() {
+  address_ = NULL;
+  size_ = 0;
 }
 
 
-VirtualMemory::~VirtualMemory() {
-  if (IsReserved()) {
-    if (0 == VirtualFree(address(), 0, MEM_RELEASE)) address_ = NULL;
+bool VirtualMemory::Commit(void* address, size_t size, bool is_executable) {
+  if (CommitRegion(address, size, is_executable)) {
+    UpdateAllocatedSpaceLimits(address, static_cast<int>(size));
+    return true;
   }
+  return false;
 }
 
 
-bool VirtualMemory::Commit(void* address, size_t size, bool is_executable) {
+bool VirtualMemory::Uncommit(void* address, size_t size) {
+  ASSERT(IsReserved());
+  return UncommitRegion(address, size);
+}
+
+
+void* VirtualMemory::ReserveRegion(size_t size) {
+  return VirtualAlloc(NULL, size, MEM_RESERVE, PAGE_NOACCESS);
+}
+
+
+bool VirtualMemory::CommitRegion(void* base, size_t size, bool is_executable) {
   int prot = is_executable ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE;
-  if (NULL == VirtualAlloc(address, size, MEM_COMMIT, prot)) {
+  if (NULL == VirtualAlloc(base, size, MEM_COMMIT, prot)) {
     return false;
   }
 
-  UpdateAllocatedSpaceLimits(address, static_cast<int>(size));
+  UpdateAllocatedSpaceLimits(base, static_cast<int>(size));
   return true;
 }
 
 
-bool VirtualMemory::Uncommit(void* address, size_t size) {
-  ASSERT(IsReserved());
-  return VirtualFree(address, size, MEM_DECOMMIT) != false;
+bool VirtualMemory::UncommitRegion(void* base, size_t size) {
+  return VirtualFree(base, size, MEM_DECOMMIT) != 0;
 }
 
 
+bool VirtualMemory::ReleaseRegion(void* base, size_t size) {
+  return VirtualFree(base, 0, MEM_RELEASE) != 0;
+}
+
+
+
 // ----------------------------------------------------------------------------
 // Win32 thread support.