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Diffstat (limited to 'src/3rdparty/angle/src/compiler/translator/RecordConstantPrecision.cpp')
-rw-r--r-- | src/3rdparty/angle/src/compiler/translator/RecordConstantPrecision.cpp | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/src/3rdparty/angle/src/compiler/translator/RecordConstantPrecision.cpp b/src/3rdparty/angle/src/compiler/translator/RecordConstantPrecision.cpp new file mode 100644 index 0000000000..14e88b749a --- /dev/null +++ b/src/3rdparty/angle/src/compiler/translator/RecordConstantPrecision.cpp @@ -0,0 +1,157 @@ +// +// 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. +// +// During parsing, all constant expressions are folded to constant union nodes. The expressions that have been +// folded may have had precision qualifiers, which should affect the precision of the consuming operation. +// If the folded constant union nodes are written to output as such they won't have any precision qualifiers, +// and their effect on the precision of the consuming operation is lost. +// +// RecordConstantPrecision is an AST traverser that inspects the precision qualifiers of constants and hoists +// the constants outside the containing expression as precision qualified named variables in case that is +// required for correct precision propagation. +// + +#include "compiler/translator/RecordConstantPrecision.h" + +#include "compiler/translator/InfoSink.h" +#include "compiler/translator/IntermNode.h" + +namespace +{ + +class RecordConstantPrecisionTraverser : public TIntermTraverser +{ + public: + RecordConstantPrecisionTraverser(); + + void visitConstantUnion(TIntermConstantUnion *node) override; + + void nextIteration(); + + bool foundHigherPrecisionConstant() const { return mFoundHigherPrecisionConstant; } + protected: + bool operandAffectsParentOperationPrecision(TIntermTyped *operand); + + bool mFoundHigherPrecisionConstant; +}; + +RecordConstantPrecisionTraverser::RecordConstantPrecisionTraverser() + : TIntermTraverser(true, false, true), + mFoundHigherPrecisionConstant(false) +{ +} + +bool RecordConstantPrecisionTraverser::operandAffectsParentOperationPrecision(TIntermTyped *operand) +{ + const TIntermBinary *parentAsBinary = getParentNode()->getAsBinaryNode(); + if (parentAsBinary != nullptr) + { + // If the constant is assigned or is used to initialize a variable, or if it's an index, + // its precision has no effect. + switch (parentAsBinary->getOp()) + { + case EOpInitialize: + case EOpAssign: + case EOpIndexDirect: + case EOpIndexDirectStruct: + case EOpIndexDirectInterfaceBlock: + case EOpIndexIndirect: + return false; + default: + break; + } + + TIntermTyped *otherOperand = parentAsBinary->getRight(); + if (otherOperand == operand) + { + otherOperand = parentAsBinary->getLeft(); + } + // If the precision of the other child is at least as high as the precision of the constant, the precision of + // the constant has no effect. + if (otherOperand->getAsConstantUnion() == nullptr && otherOperand->getPrecision() >= operand->getPrecision()) + { + return false; + } + } + + TIntermAggregate *parentAsAggregate = getParentNode()->getAsAggregate(); + if (parentAsAggregate != nullptr) + { + if (!parentAsAggregate->gotPrecisionFromChildren()) + { + // This can be either: + // * a call to an user-defined function + // * a call to a texture function + // * some other kind of aggregate + // In any of these cases the constant precision has no effect. + return false; + } + if (parentAsAggregate->isConstructor() && parentAsAggregate->getBasicType() == EbtBool) + { + return false; + } + // If the precision of operands does affect the result, but the precision of any of the other children + // has a precision that's at least as high as the precision of the constant, the precision of the constant + // has no effect. + TIntermSequence *parameters = parentAsAggregate->getSequence(); + for (TIntermNode *parameter : *parameters) + { + const TIntermTyped *typedParameter = parameter->getAsTyped(); + if (parameter != operand && typedParameter != nullptr && parameter->getAsConstantUnion() == nullptr && + typedParameter->getPrecision() >= operand->getPrecision()) + { + return false; + } + } + } + return true; +} + +void RecordConstantPrecisionTraverser::visitConstantUnion(TIntermConstantUnion *node) +{ + if (mFoundHigherPrecisionConstant) + return; + + // If the constant has lowp or undefined precision, it can't increase the precision of consuming operations. + if (node->getPrecision() < EbpMedium) + return; + + // It's possible the node has no effect on the precision of the consuming expression, depending on the + // consuming expression, and the precision of the other parameters of the expression. + if (!operandAffectsParentOperationPrecision(node)) + return; + + // Make the constant a precision-qualified named variable to make sure it affects the precision of the consuming + // expression. + TIntermSequence insertions; + insertions.push_back(createTempInitDeclaration(node, EvqConst)); + insertStatementsInParentBlock(insertions); + mReplacements.push_back(NodeUpdateEntry(getParentNode(), node, createTempSymbol(node->getType()), false)); + mFoundHigherPrecisionConstant = true; +} + +void RecordConstantPrecisionTraverser::nextIteration() +{ + nextTemporaryIndex(); + mFoundHigherPrecisionConstant = false; +} + +} // namespace + +void RecordConstantPrecision(TIntermNode *root, unsigned int *temporaryIndex) +{ + RecordConstantPrecisionTraverser traverser; + ASSERT(temporaryIndex != nullptr); + traverser.useTemporaryIndex(temporaryIndex); + // Iterate as necessary, and reset the traverser between iterations. + do + { + traverser.nextIteration(); + root->traverse(&traverser); + if (traverser.foundHigherPrecisionConstant()) + traverser.updateTree(); + } + while (traverser.foundHigherPrecisionConstant()); +} |