Move operator precedence calculation to new header

Thereby, it can be reused by clang-format and others.
Review: http://llvm-reviews.chandlerc.com/D229

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@170757 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/OperatorPrecedence.cpp b/lib/Basic/OperatorPrecedence.cpp
new file mode 100644
index 0000000..f722c2d
--- /dev/null
+++ b/lib/Basic/OperatorPrecedence.cpp
@@ -0,0 +1,76 @@
+//===--- OperatorPrecedence.cpp ---------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief Defines and computes precedence levels for binary/ternary operators.
+///
+//===----------------------------------------------------------------------===//
+#include "clang/Basic/OperatorPrecedence.h"
+
+namespace clang {
+
+prec::Level clang::getBinOpPrecedence(
+    tok::TokenKind Kind, bool GreaterThanIsOperator, bool CPlusPlus0x) {
+  switch (Kind) {
+  case tok::greater:
+    // C++ [temp.names]p3:
+    //   [...] When parsing a template-argument-list, the first
+    //   non-nested > is taken as the ending delimiter rather than a
+    //   greater-than operator. [...]
+    if (GreaterThanIsOperator)
+      return prec::Relational;
+    return prec::Unknown;
+
+  case tok::greatergreater:
+    // C++0x [temp.names]p3:
+    //
+    //   [...] Similarly, the first non-nested >> is treated as two
+    //   consecutive but distinct > tokens, the first of which is
+    //   taken as the end of the template-argument-list and completes
+    //   the template-id. [...]
+    if (GreaterThanIsOperator || !CPlusPlus0x)
+      return prec::Shift;
+    return prec::Unknown;
+
+  default:                        return prec::Unknown;
+  case tok::comma:                return prec::Comma;
+  case tok::equal:
+  case tok::starequal:
+  case tok::slashequal:
+  case tok::percentequal:
+  case tok::plusequal:
+  case tok::minusequal:
+  case tok::lesslessequal:
+  case tok::greatergreaterequal:
+  case tok::ampequal:
+  case tok::caretequal:
+  case tok::pipeequal:            return prec::Assignment;
+  case tok::question:             return prec::Conditional;
+  case tok::pipepipe:             return prec::LogicalOr;
+  case tok::ampamp:               return prec::LogicalAnd;
+  case tok::pipe:                 return prec::InclusiveOr;
+  case tok::caret:                return prec::ExclusiveOr;
+  case tok::amp:                  return prec::And;
+  case tok::exclaimequal:
+  case tok::equalequal:           return prec::Equality;
+  case tok::lessequal:
+  case tok::less:
+  case tok::greaterequal:         return prec::Relational;
+  case tok::lessless:             return prec::Shift;
+  case tok::plus:
+  case tok::minus:                return prec::Additive;
+  case tok::percent:
+  case tok::slash:
+  case tok::star:                 return prec::Multiplicative;
+  case tok::periodstar:
+  case tok::arrowstar:            return prec::PointerToMember;
+  }
+}
+
+}  // namespace clang