kc3-lang/angle/src/compiler/translator/tree_ops/SeparateDeclarations.cpp

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• Hash : 9f4b159b
  Author :
  Date : 2021-01-19T12:48:15
  

  Translator: Avoid vector copies with multi-replacement
  
  Turns push_backs into emplace_backs and changes the TIntermSequence
  constructor argument to &&.
  
  Bug: angleproject:5535
  Change-Id: I640ce879b6ade48a28dea6385ebb7a95cb8304ff
  Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2636680
  Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
  Reviewed-by: Jamie Madill <jmadill@chromium.org>
  Reviewed-by: Tim Van Patten <timvp@google.com>
  

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• src/compiler/translator/tree_ops/SeparateDeclarations.cpp

• //
  // Copyright 2002 The ANGLE Project Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  //
  // The SeparateDeclarations function processes declarations, so that in the end each declaration
  // contains only one declarator.
  // This is useful as an intermediate step when initialization needs to be separated from
  // declaration, or when things need to be unfolded out of the initializer.
  // Example:
  //     int a[1] = int[1](1), b[1] = int[1](2);
  // gets transformed when run through this class into the AST equivalent of:
  //     int a[1] = int[1](1);
  //     int b[1] = int[1](2);
  
  #include "compiler/translator/tree_ops/SeparateDeclarations.h"
  
  #include "compiler/translator/tree_util/IntermTraverse.h"
  
  namespace sh
  {
  
  namespace
  {
  
  class SeparateDeclarationsTraverser : private TIntermTraverser
  {
    public:
      ANGLE_NO_DISCARD static bool apply(TCompiler *compiler, TIntermNode *root);
  
    private:
      SeparateDeclarationsTraverser();
      bool visitDeclaration(Visit, TIntermDeclaration *node) override;
  };
  
  bool SeparateDeclarationsTraverser::apply(TCompiler *compiler, TIntermNode *root)
  {
      SeparateDeclarationsTraverser separateDecl;
      root->traverse(&separateDecl);
      return separateDecl.updateTree(compiler, root);
  }
  
  SeparateDeclarationsTraverser::SeparateDeclarationsTraverser()
      : TIntermTraverser(true, false, false)
  {}
  
  bool SeparateDeclarationsTraverser::visitDeclaration(Visit, TIntermDeclaration *node)
  {
      TIntermSequence *sequence = node->getSequence();
      if (sequence->size() > 1)
      {
          TIntermBlock *parentBlock = getParentNode()->getAsBlock();
          ASSERT(parentBlock != nullptr);
  
          TIntermSequence replacementDeclarations;
          for (size_t ii = 0; ii < sequence->size(); ++ii)
          {
              TIntermDeclaration *replacementDeclaration = new TIntermDeclaration();
  
              replacementDeclaration->appendDeclarator(sequence->at(ii)->getAsTyped());
              replacementDeclaration->setLine(sequence->at(ii)->getLine());
              replacementDeclarations.push_back(replacementDeclaration);
          }
  
          mMultiReplacements.emplace_back(parentBlock, node, std::move(replacementDeclarations));
      }
      return false;
  }
  
  }  // namespace
  
  bool SeparateDeclarations(TCompiler *compiler, TIntermNode *root)
  {
      return SeparateDeclarationsTraverser::apply(compiler, root);
  }
  
  }  // namespace sh
  

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