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//
// 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
{
TIntermSymbol *MakeNewTemporary(const TString &name, TBasicType type)
{
TType variableType(type, EbpHigh, EvqInternal);
return new TIntermSymbol(-1, name, variableType);
}
TIntermBinary *MakeNewBinary(TOperator op, TIntermTyped *left, TIntermTyped *right, const TType &resultType)
{
TIntermBinary *binary = new TIntermBinary(op);
binary->setLeft(left);
binary->setRight(right);
binary->setType(resultType);
return binary;
}
TIntermUnary *MakeNewUnary(TOperator op, TIntermTyped *operand)
{
TIntermUnary *unary = new TIntermUnary(op, operand->getType());
unary->setOperand(operand);
return unary;
}
bool ElseBlockRewriter::visitAggregate(Visit visit, TIntermAggregate *node)
{
switch (node->getOp())
{
case EOpSequence:
{
for (size_t statementIndex = 0; statementIndex != node->getSequence().size(); statementIndex++)
{
TIntermNode *statement = node->getSequence()[statementIndex];
TIntermSelection *selection = statement->getAsSelectionNode();
if (selection && selection->getFalseBlock() != NULL)
{
node->getSequence()[statementIndex] = rewriteSelection(selection);
delete selection;
}
}
}
break;
default: break;
}
return true;
}
TIntermNode *ElseBlockRewriter::rewriteSelection(TIntermSelection *selection)
{
ASSERT(selection->getFalseBlock() != NULL);
TString temporaryName = "cond_" + str(mTemporaryIndex++);
TIntermTyped *typedCondition = selection->getCondition()->getAsTyped();
TType resultType(EbtBool, EbpUndefined);
TIntermSymbol *conditionSymbolA = MakeNewTemporary(temporaryName, EbtBool);
TIntermSymbol *conditionSymbolB = MakeNewTemporary(temporaryName, EbtBool);
TIntermSymbol *conditionSymbolC = MakeNewTemporary(temporaryName, EbtBool);
TIntermBinary *storeCondition = MakeNewBinary(EOpInitialize, conditionSymbolA,
typedCondition, resultType);
TIntermUnary *negatedCondition = MakeNewUnary(EOpLogicalNot, conditionSymbolB);
TIntermSelection *falseBlock = new TIntermSelection(negatedCondition,
selection->getFalseBlock(), NULL);
TIntermSelection *newIfElse = new TIntermSelection(conditionSymbolC,
selection->getTrueBlock(), falseBlock);
TIntermAggregate *declaration = new TIntermAggregate(EOpDeclaration);
declaration->getSequence().push_back(storeCondition);
TIntermAggregate *block = new TIntermAggregate(EOpSequence);
block->getSequence().push_back(declaration);
block->getSequence().push_back(newIfElse);
return block;
}
void RewriteElseBlocks(TIntermNode *node)
{
ElseBlockRewriter rewriter;
node->traverse(&rewriter);
}
}
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