initial checkin of SkSL compiler
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1984363002
CQ_EXTRA_TRYBOTS=client.skia.compile:Build-Ubuntu-GCC-x86_64-Release-CMake-Trybot,Build-Mac-Clang-x86_64-Release-CMake-Trybot
Review-Url: https://codereview.chromium.org/1984363002
diff --git a/src/sksl/ir/SkSLPrefixExpression.h b/src/sksl/ir/SkSLPrefixExpression.h
new file mode 100644
index 0000000..53c3849
--- /dev/null
+++ b/src/sksl/ir/SkSLPrefixExpression.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SKSL_PREFIXEXPRESSION
+#define SKSL_PREFIXEXPRESSION
+
+#include "SkSLExpression.h"
+
+namespace SkSL {
+
+/**
+ * An expression modified by a unary operator appearing before it, such as '!flag'.
+ */
+struct PrefixExpression : public Expression {
+ PrefixExpression(Token::Kind op, std::unique_ptr<Expression> operand)
+ : INHERITED(operand->fPosition, kPrefix_Kind, operand->fType)
+ , fOperand(std::move(operand))
+ , fOperator(op) {}
+
+ virtual std::string description() const override {
+ return Token::OperatorName(fOperator) + fOperand->description();
+ }
+
+ const std::unique_ptr<Expression> fOperand;
+ const Token::Kind fOperator;
+
+ typedef Expression INHERITED;
+};
+
+} // namespace
+
+#endif