Introduce clang-query tool.

This tool is for interactive exploration of the Clang AST using AST matchers.
It currently allows the user to enter a matcher at an interactive prompt
and view the resulting bindings as diagnostics, AST pretty prints or AST
dumps. Example session:

$ cat foo.c
void foo(void) {}
$ clang-query foo.c --
clang-query> match functionDecl()

Match #1:

foo.c:1:1: note: "root" binds here
void foo(void) {}
^~~~~~~~~~~~~~~~~
1 match.

Differential Revision: http://llvm-reviews.chandlerc.com/D2098

llvm-svn: 194227
diff --git a/clang-tools-extra/unittests/clang-query/QueryParserTest.cpp b/clang-tools-extra/unittests/clang-query/QueryParserTest.cpp
new file mode 100644
index 0000000..06737bc
--- /dev/null
+++ b/clang-tools-extra/unittests/clang-query/QueryParserTest.cpp
@@ -0,0 +1,87 @@
+//===---- QueryParserTest.cpp - clang-query test --------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "QueryParser.h"
+#include "Query.h"
+#include "QuerySession.h"
+#include "gtest/gtest.h"
+
+using namespace clang;
+using namespace clang::query;
+
+TEST(QueryParser, NoOp) {
+  QueryRef Q = ParseQuery("");
+  EXPECT_TRUE(isa<NoOpQuery>(Q));
+
+  Q = ParseQuery("\n");
+  EXPECT_TRUE(isa<NoOpQuery>(Q));
+}
+
+TEST(QueryParser, Invalid) {
+  QueryRef Q = ParseQuery("foo");
+  ASSERT_TRUE(isa<InvalidQuery>(Q));
+  EXPECT_EQ("unknown command: foo", cast<InvalidQuery>(Q)->ErrStr);
+}
+
+TEST(QueryParser, Help) {
+  QueryRef Q = ParseQuery("help");
+  ASSERT_TRUE(isa<HelpQuery>(Q));
+
+  Q = ParseQuery("help me");
+  ASSERT_TRUE(isa<InvalidQuery>(Q));
+  EXPECT_EQ("unexpected extra input: ' me'", cast<InvalidQuery>(Q)->ErrStr);
+}
+
+TEST(QueryParser, Set) {
+  QueryRef Q = ParseQuery("set");
+  ASSERT_TRUE(isa<InvalidQuery>(Q));
+  EXPECT_EQ("expected variable name", cast<InvalidQuery>(Q)->ErrStr);
+
+  Q = ParseQuery("set foo bar");
+  ASSERT_TRUE(isa<InvalidQuery>(Q));
+  EXPECT_EQ("unknown variable: 'foo'", cast<InvalidQuery>(Q)->ErrStr);
+
+  Q = ParseQuery("set output");
+  ASSERT_TRUE(isa<InvalidQuery>(Q));
+  EXPECT_EQ("expected variable value", cast<InvalidQuery>(Q)->ErrStr);
+
+  Q = ParseQuery("set bind-root true foo");
+  ASSERT_TRUE(isa<InvalidQuery>(Q));
+  EXPECT_EQ("unexpected extra input: ' foo'", cast<InvalidQuery>(Q)->ErrStr);
+
+  Q = ParseQuery("set output foo");
+  ASSERT_TRUE(isa<InvalidQuery>(Q));
+  EXPECT_EQ("expected 'diag', 'print' or 'dump', got 'foo'",
+            cast<InvalidQuery>(Q)->ErrStr);
+
+  Q = ParseQuery("set output dump");
+  ASSERT_TRUE(isa<SetQuery<OutputKind> >(Q));
+  EXPECT_EQ(&QuerySession::OutKind, cast<SetQuery<OutputKind> >(Q)->Var);
+  EXPECT_EQ(OK_Dump, cast<SetQuery<OutputKind> >(Q)->Value);
+
+  Q = ParseQuery("set bind-root foo");
+  ASSERT_TRUE(isa<InvalidQuery>(Q));
+  EXPECT_EQ("expected 'true' or 'false', got 'foo'",
+            cast<InvalidQuery>(Q)->ErrStr);
+
+  Q = ParseQuery("set bind-root true");
+  ASSERT_TRUE(isa<SetQuery<bool> >(Q));
+  EXPECT_EQ(&QuerySession::BindRoot, cast<SetQuery<bool> >(Q)->Var);
+  EXPECT_EQ(true, cast<SetQuery<bool> >(Q)->Value);
+}
+
+TEST(QueryParser, Match) {
+  QueryRef Q = ParseQuery("match decl()");
+  ASSERT_TRUE(isa<MatchQuery>(Q));
+  EXPECT_TRUE(cast<MatchQuery>(Q)->Matcher.canConvertTo<Decl>());
+
+  Q = ParseQuery("m stmt()");
+  ASSERT_TRUE(isa<MatchQuery>(Q));
+  EXPECT_TRUE(cast<MatchQuery>(Q)->Matcher.canConvertTo<Stmt>());
+}