1 files changed, 145 insertions, 0 deletions
diff --git a/gfx/angle/checkout/src/compiler/translator/tree_util/ReplaceVariable.cpp b/gfx/angle/checkout/src/compiler/translator/tree_util/ReplaceVariable.cpp
new file mode 100644
index 0000000000..697cfe6c74
--- /dev/null
+++ b/gfx/angle/checkout/src/compiler/translator/tree_util/ReplaceVariable.cpp
@@ -0,0 +1,145 @@
+//
+// Copyright 2018 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.
+//
+// ReplaceVariable.cpp: Replace all references to a specific variable in the AST with references to
+// another variable.
+
+#include "compiler/translator/tree_util/ReplaceVariable.h"
+
+#include "compiler/translator/IntermNode.h"
+#include "compiler/translator/Symbol.h"
+#include "compiler/translator/tree_util/IntermTraverse.h"
+
+namespace sh
+{
+
+namespace
+{
+
+class ReplaceVariableTraverser : public TIntermTraverser
+{
+  public:
+    ReplaceVariableTraverser(const TVariable *toBeReplaced, const TIntermTyped *replacement)
+        : TIntermTraverser(true, false, false),
+          mToBeReplaced(toBeReplaced),
+          mReplacement(replacement)
+    {}
+
+    void visitSymbol(TIntermSymbol *node) override
+    {
+        if (&node->variable() == mToBeReplaced)
+        {
+            queueReplacement(mReplacement->deepCopy(), OriginalNode::IS_DROPPED);
+        }
+    }
+
+  private:
+    const TVariable *const mToBeReplaced;
+    const TIntermTyped *const mReplacement;
+};
+
+class ReplaceVariablesTraverser : public TIntermTraverser
+{
+  public:
+    ReplaceVariablesTraverser(const VariableReplacementMap &variableMap)
+        : TIntermTraverser(true, false, false), mVariableMap(variableMap)
+    {}
+
+    void visitSymbol(TIntermSymbol *node) override
+    {
+        auto iter = mVariableMap.find(&node->variable());
+        if (iter != mVariableMap.end())
+        {
+            queueReplacement(iter->second->deepCopy(), OriginalNode::IS_DROPPED);
+        }
+    }
+
+  private:
+    const VariableReplacementMap &mVariableMap;
+};
+
+class GetDeclaratorReplacementsTraverser : public TIntermTraverser
+{
+  public:
+    GetDeclaratorReplacementsTraverser(TSymbolTable *symbolTable,
+                                       VariableReplacementMap *variableMap)
+        : TIntermTraverser(true, false, false, symbolTable), mVariableMap(variableMap)
+    {}
+
+    bool visitDeclaration(Visit visit, TIntermDeclaration *node) override
+    {
+        const TIntermSequence &sequence = *(node->getSequence());
+
+        for (TIntermNode *decl : sequence)
+        {
+            TIntermSymbol *asSymbol = decl->getAsSymbolNode();
+            TIntermBinary *asBinary = decl->getAsBinaryNode();
+
+            if (asBinary != nullptr)
+            {
+                ASSERT(asBinary->getOp() == EOpInitialize);
+                asSymbol = asBinary->getLeft()->getAsSymbolNode();
+            }
+
+            ASSERT(asSymbol);
+            const TVariable &variable = asSymbol->variable();
+
+            ASSERT(mVariableMap->find(&variable) == mVariableMap->end());
+
+            const TVariable *replacementVariable = new TVariable(
+                mSymbolTable, variable.name(), &variable.getType(), variable.symbolType());
+
+            (*mVariableMap)[&variable] = new TIntermSymbol(replacementVariable);
+        }
+
+        return false;
+    }
+
+  private:
+    VariableReplacementMap *mVariableMap;
+};
+
+}  // anonymous namespace
+
+// Replaces every occurrence of a variable with another variable.
+[[nodiscard]] bool ReplaceVariable(TCompiler *compiler,
+                                   TIntermBlock *root,
+                                   const TVariable *toBeReplaced,
+                                   const TVariable *replacement)
+{
+    ReplaceVariableTraverser traverser(toBeReplaced, new TIntermSymbol(replacement));
+    root->traverse(&traverser);
+    return traverser.updateTree(compiler, root);
+}
+
+[[nodiscard]] bool ReplaceVariables(TCompiler *compiler,
+                                    TIntermBlock *root,
+                                    const VariableReplacementMap &variableMap)
+{
+    ReplaceVariablesTraverser traverser(variableMap);
+    root->traverse(&traverser);
+    return traverser.updateTree(compiler, root);
+}
+
+void GetDeclaratorReplacements(TSymbolTable *symbolTable,
+                               TIntermBlock *root,
+                               VariableReplacementMap *variableMap)
+{
+    GetDeclaratorReplacementsTraverser traverser(symbolTable, variableMap);
+    root->traverse(&traverser);
+}
+
+// Replaces every occurrence of a variable with a TIntermNode.
+[[nodiscard]] bool ReplaceVariableWithTyped(TCompiler *compiler,
+                                            TIntermBlock *root,
+                                            const TVariable *toBeReplaced,
+                                            const TIntermTyped *replacement)
+{
+    ReplaceVariableTraverser traverser(toBeReplaced, replacement);
+    root->traverse(&traverser);
+    return traverser.updateTree(compiler, root);
+}
+
+}  // namespace sh