diff options
Diffstat (limited to 'src/3rdparty/angle/src/compiler/translator/UnfoldShortCircuitAST.cpp')
-rw-r--r-- | src/3rdparty/angle/src/compiler/translator/UnfoldShortCircuitAST.cpp | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/src/3rdparty/angle/src/compiler/translator/UnfoldShortCircuitAST.cpp b/src/3rdparty/angle/src/compiler/translator/UnfoldShortCircuitAST.cpp new file mode 100644 index 0000000000..29c4397d56 --- /dev/null +++ b/src/3rdparty/angle/src/compiler/translator/UnfoldShortCircuitAST.cpp @@ -0,0 +1,81 @@ +// +// Copyright (c) 2002-2013 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/UnfoldShortCircuitAST.h" + +namespace +{ + +// "x || y" is equivalent to "x ? true : y". +TIntermSelection *UnfoldOR(TIntermTyped *x, TIntermTyped *y) +{ + const TType boolType(EbtBool, EbpUndefined); + ConstantUnion *u = new ConstantUnion; + u->setBConst(true); + TIntermConstantUnion *trueNode = new TIntermConstantUnion( + u, TType(EbtBool, EbpUndefined, EvqConst, 1)); + return new TIntermSelection(x, trueNode, y, boolType); +} + +// "x && y" is equivalent to "x ? y : false". +TIntermSelection *UnfoldAND(TIntermTyped *x, TIntermTyped *y) +{ + const TType boolType(EbtBool, EbpUndefined); + ConstantUnion *u = new ConstantUnion; + u->setBConst(false); + TIntermConstantUnion *falseNode = new TIntermConstantUnion( + u, TType(EbtBool, EbpUndefined, EvqConst, 1)); + return new TIntermSelection(x, y, falseNode, boolType); +} + +} // namespace anonymous + +bool UnfoldShortCircuitAST::visitBinary(Visit visit, TIntermBinary *node) +{ + TIntermSelection *replacement = NULL; + + switch (node->getOp()) + { + case EOpLogicalOr: + replacement = UnfoldOR(node->getLeft(), node->getRight()); + break; + case EOpLogicalAnd: + replacement = UnfoldAND(node->getLeft(), node->getRight()); + break; + default: + break; + } + if (replacement) + { + replacements.push_back( + NodeUpdateEntry(getParentNode(), node, replacement)); + } + return true; +} + +void UnfoldShortCircuitAST::updateTree() +{ + for (size_t ii = 0; ii < replacements.size(); ++ii) + { + const NodeUpdateEntry& entry = replacements[ii]; + ASSERT(entry.parent); + bool replaced = entry.parent->replaceChildNode( + entry.original, entry.replacement); + ASSERT(replaced); + + // In AST traversing, a parent is visited before its children. + // After we replace a node, if an immediate child is to + // be replaced, we need to make sure we don't update the replaced + // node; instead, we update the replacement node. + for (size_t jj = ii + 1; jj < replacements.size(); ++jj) + { + NodeUpdateEntry& entry2 = replacements[jj]; + if (entry2.parent == entry.original) + entry2.parent = entry.replacement; + } + } +} + |