1 files changed, 47 insertions, 0 deletions
diff --git a/gfx/angle/checkout/src/compiler/translator/tree_ops/RemoveInvariantDeclaration.cpp b/gfx/angle/checkout/src/compiler/translator/tree_ops/RemoveInvariantDeclaration.cpp
new file mode 100644
index 0000000000..5a8ca44150
--- /dev/null
+++ b/gfx/angle/checkout/src/compiler/translator/tree_ops/RemoveInvariantDeclaration.cpp
@@ -0,0 +1,47 @@
+//
+// Copyright 2016 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/tree_ops/RemoveInvariantDeclaration.h"
+
+#include "compiler/translator/tree_util/IntermTraverse.h"
+
+namespace sh
+{
+
+namespace
+{
+
+// An AST traverser that removes invariant declaration for input in fragment shader
+// when GLSL >= 4.20 and for output in vertex shader when GLSL < 4.2.
+class RemoveInvariantDeclarationTraverser : public TIntermTraverser
+{
+  public:
+    RemoveInvariantDeclarationTraverser() : TIntermTraverser(true, false, false) {}
+
+  private:
+    bool visitGlobalQualifierDeclaration(Visit visit,
+                                         TIntermGlobalQualifierDeclaration *node) override
+    {
+        if (node->isInvariant())
+        {
+            TIntermSequence emptyReplacement;
+            mMultiReplacements.emplace_back(getParentNode()->getAsBlock(), node,
+                                            std::move(emptyReplacement));
+        }
+        return false;
+    }
+};
+
+}  // anonymous namespace
+
+bool RemoveInvariantDeclaration(TCompiler *compiler, TIntermNode *root)
+{
+    RemoveInvariantDeclarationTraverser traverser;
+    root->traverse(&traverser);
+    return traverser.updateTree(compiler, root);
+}
+
+}  // namespace sh