Align base::Pickle allocations to 4k boundaries

base/pickle.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/pickle.h"
 
 #include <stdlib.h>
 
 #include <algorithm>  // for max()
 
+#include "base/bits.h"
+#include "base/macros.h"
+
 namespace base {
 
 // static
 const int Pickle::kPayloadUnit = 64;
 
 static const size_t kCapacityReadOnly = static_cast<size_t>(-1);
 
 PickleIterator::PickleIterator(const Pickle& pickle)
     : payload_(pickle.payload()),
       read_index_(0),
       end_index_(pickle.payload_size()) {
 }
 
 template <typename Type>
 inline bool PickleIterator::ReadBuiltinType(Type* result) {
   const char* read_from = GetReadPointerAndAdvance<Type>();
   if (!read_from)
     return false;
   if (sizeof(Type) > sizeof(uint32))
     memcpy(result, read_from, sizeof(*result));
   else
     *result = *reinterpret_cast<const Type*>(read_from);
   return true;
 }
 
 inline void PickleIterator::Advance(size_t size) {
-  size_t aligned_size = AlignInt(size, sizeof(uint32_t));
+  size_t aligned_size = bits::Align(size, sizeof(uint32_t));
   if (end_index_ - read_index_ < aligned_size) {
     read_index_ = end_index_;
   } else {
     read_index_ += aligned_size;
   }
 }
 
 template<typename Type>
 inline const char* PickleIterator::GetReadPointerAndAdvance() {
   if (sizeof(Type) > end_index_ - read_index_) {
@@ skipping 155 matching lines @@
   return true;
 }
 
 // Payload is uint32 aligned.
 
 Pickle::Pickle()
     : header_(NULL),
       header_size_(sizeof(Header)),
       capacity_after_header_(0),
       write_offset_(0) {
+  static_assert((Pickle::kPayloadUnit & (Pickle::kPayloadUnit - 1)) == 0,
+                "Pickle::kPayloadUnit must be a power of two");
   Resize(kPayloadUnit);
   header_->payload_size = 0;
 }
 
 Pickle::Pickle(int header_size)
     : header_(NULL),
-      header_size_(AlignInt(header_size, sizeof(uint32))),
+      header_size_(bits::Align(header_size, sizeof(uint32))),
       capacity_after_header_(0),
       write_offset_(0) {
   DCHECK_GE(static_cast<size_t>(header_size), sizeof(Header));
   DCHECK_LE(header_size, kPayloadUnit);
   Resize(kPayloadUnit);
   header_->payload_size = 0;
 }
 
 Pickle::Pickle(const char* data, int data_len)
     : header_(reinterpret_cast<Header*>(const_cast<char*>(data))),
       header_size_(0),
       capacity_after_header_(kCapacityReadOnly),
       write_offset_(0) {
   if (data_len >= static_cast<int>(sizeof(Header)))
     header_size_ = data_len - header_->payload_size;
 
   if (header_size_ > static_cast<unsigned int>(data_len))
     header_size_ = 0;
 
-  if (header_size_ != AlignInt(header_size_, sizeof(uint32)))
+  if (header_size_ != bits::Align(header_size_, sizeof(uint32)))
     header_size_ = 0;
 
   // If there is anything wrong with the data, we're not going to use it.
   if (!header_size_)
     header_ = NULL;
 }
 
 Pickle::Pickle(const Pickle& other)
     : header_(NULL),
       header_size_(other.header_size_),
@@ skipping 48 matching lines @@
 bool Pickle::WriteData(const char* data, int length) {
   return length >= 0 && WriteInt(length) && WriteBytes(data, length);
 }
 
 bool Pickle::WriteBytes(const void* data, int length) {
   WriteBytesCommon(data, length);
   return true;
 }
 
 void Pickle::Reserve(size_t length) {
-  size_t data_len = AlignInt(length, sizeof(uint32));
+  size_t data_len = bits::Align(length, sizeof(uint32));
   DCHECK_GE(data_len, length);
 #ifdef ARCH_CPU_64_BITS
   DCHECK_LE(data_len, kuint32max);
 #endif
   DCHECK_LE(write_offset_, kuint32max - data_len);
   size_t new_size = write_offset_ + data_len;
   if (new_size > capacity_after_header_)
     Resize(capacity_after_header_ * 2 + new_size);
 }
 
 void Pickle::Resize(size_t new_capacity) {
   CHECK_NE(capacity_after_header_, kCapacityReadOnly);
-  capacity_after_header_ = AlignInt(new_capacity, kPayloadUnit);
+  capacity_after_header_ = bits::Align(new_capacity, kPayloadUnit);
   void* p = realloc(header_, GetTotalAllocatedSize());
   CHECK(p);
   header_ = reinterpret_cast<Header*>(p);
 }
 
 size_t Pickle::GetTotalAllocatedSize() const {
   if (capacity_after_header_ == kCapacityReadOnly)
     return 0;
   return header_size_ + capacity_after_header_;
 }
 
 // static
 const char* Pickle::FindNext(size_t header_size,
                              const char* start,
                              const char* end) {
-  DCHECK_EQ(header_size, AlignInt(header_size, sizeof(uint32)));
+  DCHECK_EQ(header_size, bits::Align(header_size, sizeof(uint32)));
   DCHECK_LE(header_size, static_cast<size_t>(kPayloadUnit));
 
   size_t length = static_cast<size_t>(end - start);
   if (length < sizeof(Header))
     return NULL;
 
   const Header* hdr = reinterpret_cast<const Header*>(start);
   if (length < header_size || length - header_size < hdr->payload_size)
     return NULL;
   return start + header_size + hdr->payload_size;
 }
 
 template <size_t length> void Pickle::WriteBytesStatic(const void* data) {
   WriteBytesCommon(data, length);
 }
 
 template void Pickle::WriteBytesStatic<2>(const void* data);
 template void Pickle::WriteBytesStatic<4>(const void* data);
 template void Pickle::WriteBytesStatic<8>(const void* data);
 
 inline void Pickle::WriteBytesCommon(const void* data, size_t length) {
   DCHECK_NE(kCapacityReadOnly, capacity_after_header_)
       << "oops: pickle is readonly";
   MSAN_CHECK_MEM_IS_INITIALIZED(data, length);
-  size_t data_len = AlignInt(length, sizeof(uint32));
+  size_t data_len = bits::Align(length, sizeof(uint32));
   DCHECK_GE(data_len, length);
 #ifdef ARCH_CPU_64_BITS
   DCHECK_LE(data_len, kuint32max);
 #endif
   DCHECK_LE(write_offset_, kuint32max - data_len);
   size_t new_size = write_offset_ + data_len;
   if (new_size > capacity_after_header_) {
-    Resize(std::max(capacity_after_header_ * 2, new_size));
+    size_t new_capacity = capacity_after_header_ * 2;
+    const size_t kPickleHeapAlign = 4096;
+    if (new_capacity > kPickleHeapAlign)
+      new_capacity = bits::Align(new_capacity, kPickleHeapAlign) - kPayloadUnit;
+    Resize(std::max(new_capacity, new_size));
   }
 
   char* write = mutable_payload() + write_offset_;
   memcpy(write, data, length);
   memset(write + length, 0, data_len - length);
   header_->payload_size = static_cast<uint32>(new_size);
   write_offset_ = new_size;
 }
 
 }  // namespace base