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

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• Hash : a223430c
  Author :
  Date : 2016-08-31T12:05:39
  

  Promote unary nodes automatically
  
  Unary nodes now get their type set automatically based on the
  operation and operand. The operand should only be changed to another
  of the same type after the node is constructed. The operation can't
  be changed on unary and binary nodes after they've been constructed.
  
  BUG=angleproject:1490
  TEST=angle_unittests
  
  Change-Id: Ib1ea3dcb1162261966c02d5f03d8091cf647fac1
  Reviewed-on: https://chromium-review.googlesource.com/378935
  Reviewed-by: Jamie Madill <jmadill@chromium.org>
  Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
  

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• src/compiler/translator/RewriteElseBlocks.cpp

• //
  // Copyright (c) 2014 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.
  //
  // RewriteElseBlocks.cpp: Implementation for tree transform to change
  //   all if-else blocks to if-if blocks.
  //
  
  #include "compiler/translator/RewriteElseBlocks.h"
  #include "compiler/translator/NodeSearch.h"
  #include "compiler/translator/SymbolTable.h"
  
  namespace sh
  {
  
  namespace
  {
  
  class ElseBlockRewriter : public TIntermTraverser
  {
    public:
      ElseBlockRewriter();
  
    protected:
      bool visitAggregate(Visit visit, TIntermAggregate *aggregate) override;
  
    private:
      const TType *mFunctionType;
  
      TIntermNode *rewriteSelection(TIntermSelection *selection);
  };
  
  ElseBlockRewriter::ElseBlockRewriter()
      : TIntermTraverser(true, false, true),
        mFunctionType(NULL)
  {}
  
  bool ElseBlockRewriter::visitAggregate(Visit visit, TIntermAggregate *node)
  {
      switch (node->getOp())
      {
        case EOpSequence:
          if (visit == PostVisit)
          {
              for (size_t statementIndex = 0; statementIndex != node->getSequence()->size(); statementIndex++)
              {
                  TIntermNode *statement = (*node->getSequence())[statementIndex];
                  TIntermSelection *selection = statement->getAsSelectionNode();
                  if (selection && selection->getFalseBlock() != nullptr)
                  {
                      // Check for if / else if
                      TIntermSelection *elseIfBranch = selection->getFalseBlock()->getAsSelectionNode();
                      if (elseIfBranch)
                      {
                          selection->replaceChildNode(elseIfBranch, rewriteSelection(elseIfBranch));
                          delete elseIfBranch;
                      }
  
                      (*node->getSequence())[statementIndex] = rewriteSelection(selection);
                      delete selection;
                  }
              }
          }
          break;
  
        case EOpFunction:
          // Store the current function context (see comment below)
          mFunctionType = ((visit == PreVisit) ? &node->getType() : NULL);
          break;
  
        default: break;
      }
  
      return true;
  }
  
  TIntermNode *ElseBlockRewriter::rewriteSelection(TIntermSelection *selection)
  {
      ASSERT(selection != nullptr);
  
      nextTemporaryIndex();
  
      TIntermTyped *typedCondition = selection->getCondition()->getAsTyped();
      TIntermAggregate *storeCondition = createTempInitDeclaration(typedCondition);
  
      TIntermSelection *falseBlock = nullptr;
  
      TType boolType(EbtBool, EbpUndefined, EvqTemporary);
  
      if (selection->getFalseBlock())
      {
          TIntermAggregate *negatedElse = nullptr;
          // crbug.com/346463
          // D3D generates error messages claiming a function has no return value, when rewriting
          // an if-else clause that returns something non-void in a function. By appending dummy
          // returns (that are unreachable) we can silence this compile error.
          if (mFunctionType && mFunctionType->getBasicType() != EbtVoid)
          {
              TString typeString = mFunctionType->getStruct() ? mFunctionType->getStruct()->name() :
                  mFunctionType->getBasicString();
              TString rawText = "return (" + typeString + ")0";
              TIntermRaw *returnNode = new TIntermRaw(*mFunctionType, rawText);
              negatedElse = new TIntermAggregate(EOpSequence);
              negatedElse->getSequence()->push_back(returnNode);
          }
  
          TIntermSymbol *conditionSymbolElse = createTempSymbol(boolType);
          TIntermUnary *negatedCondition     = new TIntermUnary(EOpLogicalNot, conditionSymbolElse);
          falseBlock = new TIntermSelection(negatedCondition,
                                            selection->getFalseBlock(), negatedElse);
      }
  
      TIntermSymbol *conditionSymbolSel = createTempSymbol(boolType);
      TIntermSelection *newSelection = new TIntermSelection(conditionSymbolSel, selection->getTrueBlock(), falseBlock);
  
      TIntermAggregate *block = new TIntermAggregate(EOpSequence);
      block->getSequence()->push_back(storeCondition);
      block->getSequence()->push_back(newSelection);
  
      return block;
  }
  
  }
  
  void RewriteElseBlocks(TIntermNode *node, unsigned int *temporaryIndex)
  {
      ElseBlockRewriter rewriter;
      rewriter.useTemporaryIndex(temporaryIndex);
      node->traverse(&rewriter);
  }
  
  }
  

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