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

• Show log

  Commit

• Hash : 8ad9e757
  Author :
  Date : 2017-01-16T19:55:20
  

  Always store function headers in TIntermFunctionPrototype nodes
  
  TIntermFunctionDefinition nodes now have a TIntermFunctionPrototype
  child that stores the function signature, instead of having a separate
  type and an aggregate child that stores the parameters.
  
  This makes parsing functions simpler, and paves the way for further
  simplifications of function parsing, like reducing conversions between
  symbol table structures and AST structures.
  
  TIntermAggregate is now only used for function calls.
  
  BUG=angleproject:1490
  TEST=angle_unittests, angle_end2end_tests
  
  Change-Id: Ib56a77b5ef5123b142963a18499690bf37fed987
  Reviewed-on: https://chromium-review.googlesource.com/427945
  Reviewed-by: Jamie Madill <jmadill@chromium.org>
  Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
  

Download

• 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/Intermediate.h"
  #include "compiler/translator/NodeSearch.h"
  #include "compiler/translator/SymbolTable.h"
  
  namespace sh
  {
  
  namespace
  {
  
  class ElseBlockRewriter : public TIntermTraverser
  {
    public:
      ElseBlockRewriter();
  
    protected:
      bool visitFunctionDefinition(Visit visit, TIntermFunctionDefinition *aggregate) override;
      bool visitBlock(Visit visit, TIntermBlock *block) override;
  
    private:
      const TType *mFunctionType;
  
      TIntermNode *rewriteIfElse(TIntermIfElse *ifElse);
  };
  
  ElseBlockRewriter::ElseBlockRewriter() : TIntermTraverser(true, false, true), mFunctionType(NULL)
  {
  }
  
  bool ElseBlockRewriter::visitFunctionDefinition(Visit visit, TIntermFunctionDefinition *node)
  {
      // Store the current function context (see comment below)
      mFunctionType = ((visit == PreVisit) ? &node->getFunctionPrototype()->getType() : nullptr);
      return true;
  }
  
  bool ElseBlockRewriter::visitBlock(Visit visit, TIntermBlock *node)
  {
      if (visit == PostVisit)
      {
          for (size_t statementIndex = 0; statementIndex != node->getSequence()->size();
               statementIndex++)
          {
              TIntermNode *statement = (*node->getSequence())[statementIndex];
              TIntermIfElse *ifElse  = statement->getAsIfElseNode();
              if (ifElse && ifElse->getFalseBlock() != nullptr)
              {
                  (*node->getSequence())[statementIndex] = rewriteIfElse(ifElse);
              }
          }
      }
      return true;
  }
  
  TIntermNode *ElseBlockRewriter::rewriteIfElse(TIntermIfElse *ifElse)
  {
      ASSERT(ifElse != nullptr);
  
      nextTemporaryIndex();
  
      TIntermDeclaration *storeCondition = createTempInitDeclaration(ifElse->getCondition());
  
      TIntermBlock *falseBlock = nullptr;
  
      TType boolType(EbtBool, EbpUndefined, EvqTemporary);
  
      if (ifElse->getFalseBlock())
      {
          TIntermBlock *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 TIntermBlock();
              negatedElse->getSequence()->push_back(returnNode);
          }
  
          TIntermSymbol *conditionSymbolElse = createTempSymbol(boolType);
          TIntermUnary *negatedCondition     = new TIntermUnary(EOpLogicalNot, conditionSymbolElse);
          TIntermIfElse *falseIfElse =
              new TIntermIfElse(negatedCondition, ifElse->getFalseBlock(), negatedElse);
          falseBlock = TIntermediate::EnsureBlock(falseIfElse);
      }
  
      TIntermSymbol *conditionSymbolSel = createTempSymbol(boolType);
      TIntermIfElse *newIfElse =
          new TIntermIfElse(conditionSymbolSel, ifElse->getTrueBlock(), falseBlock);
  
      TIntermBlock *block = new TIntermBlock();
      block->getSequence()->push_back(storeCondition);
      block->getSequence()->push_back(newIfElse);
  
      return block;
  }
  }
  
  void RewriteElseBlocks(TIntermNode *node, unsigned int *temporaryIndex)
  {
      ElseBlockRewriter rewriter;
      rewriter.useTemporaryIndex(temporaryIndex);
      node->traverse(&rewriter);
  }
  }
  

Download