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

• Show log

  Commit

• Hash : d0bad2c7
  Author :
  Date : 2016-09-09T18:01:16
  

  Split ternary node class from TIntermSelection
  
  Ternary operator nodes are typed parts of expressions, they always
  have two children and the children are also guaranteed to be
  TIntermTyped. "If" selection nodes can't be a part of an expression,
  they can have either one or two children and the children are code
  blocks. Due to all of these differences it makes sense to store these
  using two different AST node classes.
  
  BUG=angleproject:1490
  TEST=angle_unittests
  
  Change-Id: I913ab1d806e3cdb5c21106f078cc9c0b6c72ac54
  Reviewed-on: https://chromium-review.googlesource.com/384512
  Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
  Reviewed-by: Corentin Wallez <cwallez@chromium.org>
  

Download

• src/compiler/translator/RemoveSwitchFallThrough.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.
  //
  
  #include "compiler/translator/RemoveSwitchFallThrough.h"
  
  TIntermAggregate *RemoveSwitchFallThrough::removeFallThrough(TIntermAggregate *statementList)
  {
      RemoveSwitchFallThrough rm(statementList);
      ASSERT(statementList);
      statementList->traverse(&rm);
      bool lastStatementWasBreak = rm.mLastStatementWasBreak;
      rm.mLastStatementWasBreak = true;
      rm.handlePreviousCase();
      if (!lastStatementWasBreak)
      {
          TIntermBranch *finalBreak = new TIntermBranch(EOpBreak, nullptr);
          rm.mStatementListOut->getSequence()->push_back(finalBreak);
      }
      return rm.mStatementListOut;
  }
  
  RemoveSwitchFallThrough::RemoveSwitchFallThrough(TIntermAggregate *statementList)
      : TIntermTraverser(true, false, false),
        mStatementList(statementList),
        mLastStatementWasBreak(false),
        mPreviousCase(nullptr)
  {
      mStatementListOut = new TIntermAggregate();
      mStatementListOut->setOp(EOpSequence);
  }
  
  void RemoveSwitchFallThrough::visitSymbol(TIntermSymbol *node)
  {
      // Note that this assumes that switch statements which don't begin by a case statement
      // have already been weeded out in validation.
      mPreviousCase->getSequence()->push_back(node);
      mLastStatementWasBreak = false;
  }
  
  void RemoveSwitchFallThrough::visitConstantUnion(TIntermConstantUnion *node)
  {
      // Conditions of case labels are not traversed, so this is some other constant
      // Could be just a statement like "0;"
      mPreviousCase->getSequence()->push_back(node);
      mLastStatementWasBreak = false;
  }
  
  bool RemoveSwitchFallThrough::visitBinary(Visit, TIntermBinary *node)
  {
      mPreviousCase->getSequence()->push_back(node);
      mLastStatementWasBreak = false;
      return false;
  }
  
  bool RemoveSwitchFallThrough::visitUnary(Visit, TIntermUnary *node)
  {
      mPreviousCase->getSequence()->push_back(node);
      mLastStatementWasBreak = false;
      return false;
  }
  
  bool RemoveSwitchFallThrough::visitTernary(Visit, TIntermTernary *node)
  {
      mPreviousCase->getSequence()->push_back(node);
      mLastStatementWasBreak = false;
      return false;
  }
  
  bool RemoveSwitchFallThrough::visitSelection(Visit, TIntermSelection *node)
  {
      mPreviousCase->getSequence()->push_back(node);
      mLastStatementWasBreak = false;
      return false;
  }
  
  bool RemoveSwitchFallThrough::visitSwitch(Visit, TIntermSwitch *node)
  {
      mPreviousCase->getSequence()->push_back(node);
      mLastStatementWasBreak = false;
      // Don't go into nested switch statements
      return false;
  }
  
  void RemoveSwitchFallThrough::outputSequence(TIntermSequence *sequence, size_t startIndex)
  {
      for (size_t i = startIndex; i < sequence->size(); ++i)
      {
          mStatementListOut->getSequence()->push_back(sequence->at(i));
      }
  }
  
  void RemoveSwitchFallThrough::handlePreviousCase()
  {
      if (mPreviousCase)
          mCasesSharingBreak.push_back(mPreviousCase);
      if (mLastStatementWasBreak)
      {
          bool labelsWithNoStatements = true;
          for (size_t i = 0; i < mCasesSharingBreak.size(); ++i)
          {
              if (mCasesSharingBreak.at(i)->getSequence()->size() > 1)
              {
                  labelsWithNoStatements = false;
              }
              if (labelsWithNoStatements)
              {
                  // Fall-through is allowed in case the label has no statements.
                  outputSequence(mCasesSharingBreak.at(i)->getSequence(), 0);
              }
              else
              {
                  // Include all the statements that this case can fall through under the same label.
                  for (size_t j = i; j < mCasesSharingBreak.size(); ++j)
                  {
                      size_t startIndex = j > i ? 1 : 0; // Add the label only from the first sequence.
                      outputSequence(mCasesSharingBreak.at(j)->getSequence(), startIndex);
  
                  }
              }
          }
          mCasesSharingBreak.clear();
      }
      mLastStatementWasBreak = false;
      mPreviousCase = nullptr;
  }
  
  bool RemoveSwitchFallThrough::visitCase(Visit, TIntermCase *node)
  {
      handlePreviousCase();
      mPreviousCase = new TIntermAggregate();
      mPreviousCase->setOp(EOpSequence);
      mPreviousCase->getSequence()->push_back(node);
      // Don't traverse the condition of the case statement
      return false;
  }
  
  bool RemoveSwitchFallThrough::visitAggregate(Visit, TIntermAggregate *node)
  {
      if (node != mStatementList)
      {
          mPreviousCase->getSequence()->push_back(node);
          mLastStatementWasBreak = false;
          return false;
      }
      return true;
  }
  
  bool RemoveSwitchFallThrough::visitLoop(Visit, TIntermLoop *node)
  {
      mPreviousCase->getSequence()->push_back(node);
      mLastStatementWasBreak = false;
      return false;
  }
  
  bool RemoveSwitchFallThrough::visitBranch(Visit, TIntermBranch *node)
  {
      mPreviousCase->getSequence()->push_back(node);
      // TODO: Verify that accepting return or continue statements here doesn't cause problems.
      mLastStatementWasBreak = true;
      return false;
  }
  

Download