kc3-lang/angle/src/compiler/translator/PruneEmptyDeclarations.cpp

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• Author : Jamie Madill
  Date : 2016-12-12 14:42:19
  Hash : d7b1ab58
  Message : Fix up translator style. Using git cl format. BUG=angleproject:650 Change-Id: I7d3f98d2b0dcfb0a8de6c35327db74e55c28d761 Reviewed-on: https://chromium-review.googlesource.com/419059 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>

• src/compiler/translator/PruneEmptyDeclarations.cpp

• //
  // Copyright (c) 2002-2015 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 PruneEmptyDeclarations function prunes unnecessary empty declarations and declarators from
  // the AST.
  
  #include "compiler/translator/PruneEmptyDeclarations.h"
  
  #include "compiler/translator/IntermNode.h"
  
  namespace sh
  {
  
  namespace
  {
  
  class PruneEmptyDeclarationsTraverser : private TIntermTraverser
  {
    public:
      static void apply(TIntermNode *root);
  
    private:
      PruneEmptyDeclarationsTraverser();
      bool visitDeclaration(Visit, TIntermDeclaration *node) override;
  };
  
  void PruneEmptyDeclarationsTraverser::apply(TIntermNode *root)
  {
      PruneEmptyDeclarationsTraverser prune;
      root->traverse(&prune);
      prune.updateTree();
  }
  
  PruneEmptyDeclarationsTraverser::PruneEmptyDeclarationsTraverser()
      : TIntermTraverser(true, false, false)
  {
  }
  
  bool PruneEmptyDeclarationsTraverser::visitDeclaration(Visit, TIntermDeclaration *node)
  {
      TIntermSequence *sequence = node->getSequence();
      if (sequence->size() >= 1)
      {
          TIntermSymbol *sym = sequence->front()->getAsSymbolNode();
          // Prune declarations without a variable name, unless it's an interface block declaration.
          if (sym != nullptr && sym->getSymbol() == "" && !sym->isInterfaceBlock())
          {
              if (sequence->size() > 1)
              {
                  // Generate a replacement that will remove the empty declarator in the beginning of
                  // a declarator list. Example of a declaration that will be changed:
                  // float, a;
                  // will be changed to
                  // float a;
                  // This applies also to struct declarations.
                  TIntermSequence emptyReplacement;
                  mMultiReplacements.push_back(
                      NodeReplaceWithMultipleEntry(node, sym, emptyReplacement));
              }
              else if (sym->getBasicType() != EbtStruct)
              {
                  // Single struct declarations may just declare the struct type and no variables, so
                  // they should not be pruned. All other single empty declarations can be pruned
                  // entirely. Example of an empty declaration that will be pruned:
                  // float;
                  TIntermSequence emptyReplacement;
                  TIntermBlock *parentAsBlock = getParentNode()->getAsBlock();
                  // The declaration may be inside a block or in a loop init expression.
                  ASSERT(parentAsBlock != nullptr || getParentNode()->getAsLoopNode() != nullptr);
                  if (parentAsBlock)
                  {
                      mMultiReplacements.push_back(
                          NodeReplaceWithMultipleEntry(parentAsBlock, node, emptyReplacement));
                  }
                  else
                  {
                      queueReplacement(node, nullptr, OriginalNode::IS_DROPPED);
                  }
              }
              else if (sym->getType().getQualifier() != EvqGlobal &&
                       sym->getType().getQualifier() != EvqTemporary)
              {
                  // We've hit an empty struct declaration with a qualifier, for example like
                  // this:
                  // const struct a { int i; };
                  // NVIDIA GL driver version 367.27 doesn't accept this kind of declarations, so
                  // we convert the declaration to a regular struct declaration. This is okay,
                  // since ESSL 1.00 spec section 4.1.8 says about structs that "The optional
                  // qualifiers only apply to any declarators, and are not part of the type being
                  // defined for name."
  
                  if (mInGlobalScope)
                  {
                      sym->getTypePointer()->setQualifier(EvqGlobal);
                  }
                  else
                  {
                      sym->getTypePointer()->setQualifier(EvqTemporary);
                  }
              }
          }
      }
      return false;
  }
  
  }  // namespace
  
  void PruneEmptyDeclarations(TIntermNode *root)
  {
      PruneEmptyDeclarationsTraverser::apply(root);
  }
  
  }  // namespace sh