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Diffstat (limited to 'third_party/protobuf/3.6.0/src/google/protobuf/compiler/cpp/cpp_padding_optimizer.cc')
| -rw-r--r-- | third_party/protobuf/3.6.0/src/google/protobuf/compiler/cpp/cpp_padding_optimizer.cc | 220 |
1 files changed, 0 insertions, 220 deletions
diff --git a/third_party/protobuf/3.6.0/src/google/protobuf/compiler/cpp/cpp_padding_optimizer.cc b/third_party/protobuf/3.6.0/src/google/protobuf/compiler/cpp/cpp_padding_optimizer.cc deleted file mode 100644 index e9303865c0..0000000000 --- a/third_party/protobuf/3.6.0/src/google/protobuf/compiler/cpp/cpp_padding_optimizer.cc +++ /dev/null @@ -1,220 +0,0 @@ -// Protocol Buffers - Google's data interchange format -// Copyright 2008 Google Inc. All rights reserved. -// https://developers.google.com/protocol-buffers/ -// -// 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 with the -// distribution. -// * Neither the name of Google Inc. nor the names of its -// contributors may be used to endorse or promote products derived from -// this software without specific prior written permission. -// -// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS -// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT -// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR -// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT -// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, -// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT -// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, -// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY -// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT -// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE -// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - -#include <google/protobuf/compiler/cpp/cpp_padding_optimizer.h> - -#include <google/protobuf/compiler/cpp/cpp_helpers.h> - -namespace google { -namespace protobuf { -namespace compiler { -namespace cpp { - -namespace { - -// FieldGroup is just a helper for PaddingOptimizer below. It holds a vector of -// fields that are grouped together because they have compatible alignment, and -// a preferred location in the final field ordering. -class FieldGroup { - public: - FieldGroup() : preferred_location_(0) {} - - // A group with a single field. - FieldGroup(float preferred_location, const FieldDescriptor* field) - : preferred_location_(preferred_location), fields_(1, field) {} - - // Append the fields in 'other' to this group. - void Append(const FieldGroup& other) { - if (other.fields_.empty()) { - return; - } - // Preferred location is the average among all the fields, so we weight by - // the number of fields on each FieldGroup object. - preferred_location_ = (preferred_location_ * fields_.size() + - (other.preferred_location_ * other.fields_.size())) / - (fields_.size() + other.fields_.size()); - fields_.insert(fields_.end(), other.fields_.begin(), other.fields_.end()); - } - - void SetPreferredLocation(float location) { preferred_location_ = location; } - const std::vector<const FieldDescriptor*>& fields() const { return fields_; } - - // FieldGroup objects sort by their preferred location. - bool operator<(const FieldGroup& other) const { - return preferred_location_ < other.preferred_location_; - } - - private: - // "preferred_location_" is an estimate of where this group should go in the - // final list of fields. We compute this by taking the average index of each - // field in this group in the original ordering of fields. This is very - // approximate, but should put this group close to where its member fields - // originally went. - float preferred_location_; - std::vector<const FieldDescriptor*> fields_; - // We rely on the default copy constructor and operator= so this type can be - // used in a vector. -}; - -} // namespace - -// Reorder 'fields' so that if the fields are output into a c++ class in the new -// order, fields of similar family (see below) are together and within each -// family, alignment padding is minimized. -// -// We try to do this while keeping each field as close as possible to its field -// number order so that we don't reduce cache locality much for function that -// access each field in order. Originally, OptimizePadding used declaration -// order for its decisions, but generated code minus the serializer/parsers uses -// the output of OptimizePadding as well (stored in -// MessageGenerator::optimized_order_). Since the serializers use field number -// order, we use that as a tie-breaker. -// -// We classify each field into a particular "family" of fields, that we perform -// the same operation on in our generated functions. -// -// REPEATED is placed first, as the C++ compiler automatically initializes -// these fields in layout order. -// -// STRING is grouped next, as our Clear/SharedCtor/SharedDtor walks it and -// calls ArenaStringPtr::Destroy on each. -// -// -// MESSAGE is grouped next, as our Clear/SharedDtor code walks it and calls -// delete on each. We initialize these fields with a NULL pointer (see -// MessageFieldGenerator::GenerateConstructorCode), which allows them to be -// memset. -// -// ZERO_INITIALIZABLE is memset in Clear/SharedCtor -// -// OTHER these fields are initialized one-by-one. -void PaddingOptimizer::OptimizeLayout( - std::vector<const FieldDescriptor*>* fields, const Options& options) { - // The sorted numeric order of Family determines the declaration order in the - // memory layout. - enum Family { - REPEATED = 0, - STRING = 1, - MESSAGE = 3, - ZERO_INITIALIZABLE = 4, - OTHER = 5, - kMaxFamily - }; - - // First divide fields into those that align to 1 byte, 4 bytes or 8 bytes. - std::vector<FieldGroup> aligned_to_1[kMaxFamily]; - std::vector<FieldGroup> aligned_to_4[kMaxFamily]; - std::vector<FieldGroup> aligned_to_8[kMaxFamily]; - for (int i = 0; i < fields->size(); ++i) { - const FieldDescriptor* field = (*fields)[i]; - - Family f = OTHER; - if (field->is_repeated()) { - f = REPEATED; - } else if (field->cpp_type() == FieldDescriptor::CPPTYPE_STRING) { - f = STRING; - } else if (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) { - f = MESSAGE; - - } else if (CanInitializeByZeroing(field)) { - f = ZERO_INITIALIZABLE; - } - - const int j = field->number(); - switch (EstimateAlignmentSize(field)) { - case 1: - aligned_to_1[f].push_back(FieldGroup(j, field)); - break; - case 4: - aligned_to_4[f].push_back(FieldGroup(j, field)); - break; - case 8: - aligned_to_8[f].push_back(FieldGroup(j, field)); - break; - default: - GOOGLE_LOG(FATAL) << "Unknown alignment size " << EstimateAlignmentSize(field) - << "for a field " << field->full_name() << "."; - } - } - - // For each family, group fields to optimize padding. - for (int f = 0; f < kMaxFamily; f++) { - // Now group fields aligned to 1 byte into sets of 4, and treat those like a - // single field aligned to 4 bytes. - for (int i = 0; i < aligned_to_1[f].size(); i += 4) { - FieldGroup field_group; - for (int j = i; j < aligned_to_1[f].size() && j < i + 4; ++j) { - field_group.Append(aligned_to_1[f][j]); - } - aligned_to_4[f].push_back(field_group); - } - // Sort by preferred location to keep fields as close to their field number - // order as possible. Using stable_sort ensures that the output is - // consistent across runs. - std::stable_sort(aligned_to_4[f].begin(), aligned_to_4[f].end()); - - // Now group fields aligned to 4 bytes (or the 4-field groups created above) - // into pairs, and treat those like a single field aligned to 8 bytes. - for (int i = 0; i < aligned_to_4[f].size(); i += 2) { - FieldGroup field_group; - for (int j = i; j < aligned_to_4[f].size() && j < i + 2; ++j) { - field_group.Append(aligned_to_4[f][j]); - } - if (i == aligned_to_4[f].size() - 1) { - if (f == OTHER) { - // Move incomplete 4-byte block to the beginning. This is done to - // pair with the (possible) leftover blocks from the - // ZERO_INITIALIZABLE family. - field_group.SetPreferredLocation(-1); - } else { - // Move incomplete 4-byte block to the end. - field_group.SetPreferredLocation(fields->size() + 1); - } - } - aligned_to_8[f].push_back(field_group); - } - // Sort by preferred location. - std::stable_sort(aligned_to_8[f].begin(), aligned_to_8[f].end()); - } - - // Now pull out all the FieldDescriptors in order. - fields->clear(); - for (int f = 0; f < kMaxFamily; ++f) { - for (int i = 0; i < aligned_to_8[f].size(); ++i) { - fields->insert(fields->end(), aligned_to_8[f][i].fields().begin(), - aligned_to_8[f][i].fields().end()); - } - } -} - -} // namespace cpp -} // namespace compiler -} // namespace protobuf -} // namespace google |