[clang-query] Add option to print matcher expression

Summary:
This is useful if using clang-query -f with a file containing multiple
matchers.

Reviewers: aaron.ballman

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D52859

llvm-svn: 344840

1 files changed, 8 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-query/Query.cpp b/clang-tools-extra/clang-query/Query.cpp
index 63b4f3579b9..463e52c5806 100644
--- a/clang-tools-extra/clang-query/Query.cpp
+++ b/clang-tools-extra/clang-query/Query.cpp
@@ -41,6 +41,8 @@ bool HelpQuery::run(llvm::raw_ostream &OS, QuerySession &QS) const {
         "as part of other expressions.\n"
         "  set bind-root (true|false)        "
         "Set whether to bind the root matcher to \"root\".\n"
+        "  set print-matcher (true|false)    "
+        "Set whether to print the current matcher,\n"
         "  set output (diag|print|dump)      "
         "Set whether to print bindings as diagnostics,\n"
         "                                    "
@@ -86,6 +88,12 @@ bool MatchQuery::run(llvm::raw_ostream &OS, QuerySession &QS) const {
     }
     Finder.matchAST(AST->getASTContext());
 
+    if (QS.PrintMatcher) {
+      std::string prefixText = "Matcher: ";
+      OS << "\n  " << prefixText << Source << "\n";
+      OS << "  " << std::string(prefixText.size() + Source.size(), '=') << '\n';
+    }
+
     for (auto MI = Matches.begin(), ME = Matches.end(); MI != ME; ++MI) {
       OS << "\nMatch #" << ++MatchCount << ":\n\n";