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Diffstat (limited to 'src/3rdparty/angle/src/compiler/translator/PruneEmptyDeclarations.cpp')
-rw-r--r-- | src/3rdparty/angle/src/compiler/translator/PruneEmptyDeclarations.cpp | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/src/3rdparty/angle/src/compiler/translator/PruneEmptyDeclarations.cpp b/src/3rdparty/angle/src/compiler/translator/PruneEmptyDeclarations.cpp new file mode 100644 index 0000000000..ef62dbfce7 --- /dev/null +++ b/src/3rdparty/angle/src/compiler/translator/PruneEmptyDeclarations.cpp @@ -0,0 +1,81 @@ +// +// 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. +// +// The PruneEmptyDeclarations function prunes unnecessary empty declarations and declarators from the AST. + +#include "compiler/translator/PruneEmptyDeclarations.h" + +#include "compiler/translator/IntermNode.h" + +namespace +{ + +class PruneEmptyDeclarationsTraverser : private TIntermTraverser +{ + public: + static void apply(TIntermNode *root); + private: + PruneEmptyDeclarationsTraverser(); + bool visitAggregate(Visit, TIntermAggregate *node) override; +}; + +void PruneEmptyDeclarationsTraverser::apply(TIntermNode *root) +{ + PruneEmptyDeclarationsTraverser prune; + root->traverse(&prune); + prune.updateTree(); +} + +PruneEmptyDeclarationsTraverser::PruneEmptyDeclarationsTraverser() + : TIntermTraverser(true, false, false) +{ +} + +bool PruneEmptyDeclarationsTraverser::visitAggregate(Visit, TIntermAggregate *node) +{ + if (node->getOp() == EOpDeclaration) + { + TIntermSequence *sequence = node->getSequence(); + if (sequence->size() >= 1) + { + TIntermSymbol *sym = sequence->front()->getAsSymbolNode(); + // Prune declarations without a variable name, unless it's an interface block declaration. + if (sym != nullptr && sym->getSymbol() == "" && !sym->isInterfaceBlock()) + { + if (sequence->size() > 1) + { + // Generate a replacement that will remove the empty declarator in the beginning of a declarator + // list. Example of a declaration that will be changed: + // float, a; + // will be changed to + // float a; + // This applies also to struct declarations. + TIntermSequence emptyReplacement; + mMultiReplacements.push_back(NodeReplaceWithMultipleEntry(node, sym, emptyReplacement)); + } + else if (sym->getBasicType() != EbtStruct) + { + // Single struct declarations may just declare the struct type and no variables, so they should + // not be pruned. All other single empty declarations can be pruned entirely. Example of an empty + // declaration that will be pruned: + // float; + TIntermSequence emptyReplacement; + TIntermAggregate *parentAgg = getParentNode()->getAsAggregate(); + ASSERT(parentAgg != nullptr); + mMultiReplacements.push_back(NodeReplaceWithMultipleEntry(parentAgg, node, emptyReplacement)); + } + } + } + return false; + } + return true; +} + +} // namespace + +void PruneEmptyDeclarations(TIntermNode *root) +{ + PruneEmptyDeclarationsTraverser::apply(root); +} |