[clang-tidy] Add UnnecessaryCopyInitialization check to new "performance" module in ClangTidy
Summary:
The patch adds a new ClangTidy check that detects when expensive-to-copy types are unnecessarily copy initialized from a const reference that has the same or are larger scope than the copy.
It currently only detects this when the copied variable is const qualified. But this will be extended to non const variables if they are only used in a const fashion.
Reviewers: alexfh
Subscribers: cfe-commits
Patch by Felix Berger!
Differential Revision: http://reviews.llvm.org/D15623
llvm-svn: 256632
diff --git a/clang-tools-extra/clang-tidy/utils/LexerUtils.cpp b/clang-tools-extra/clang-tidy/utils/LexerUtils.cpp
new file mode 100644
index 0000000..239c0f7
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/utils/LexerUtils.cpp
@@ -0,0 +1,39 @@
+//===--- LexerUtils.cpp - clang-tidy---------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "LexerUtils.h"
+
+namespace clang {
+namespace tidy {
+namespace lexer_utils {
+
+Token getPreviousNonCommentToken(const ASTContext &Context,
+ SourceLocation Location) {
+ const auto &SourceManager = Context.getSourceManager();
+ Token Token;
+ Token.setKind(tok::unknown);
+ Location = Location.getLocWithOffset(-1);
+ auto StartOfFile =
+ SourceManager.getLocForStartOfFile(SourceManager.getFileID(Location));
+ while (Location != StartOfFile) {
+ Location = Lexer::GetBeginningOfToken(Location, SourceManager,
+ Context.getLangOpts());
+ if (!Lexer::getRawToken(Location, Token, SourceManager,
+ Context.getLangOpts()) &&
+ !Token.is(tok::comment)) {
+ break;
+ }
+ Location = Location.getLocWithOffset(-1);
+ }
+ return Token;
+}
+
+} // namespace lexer_utils
+} // namespace tidy
+} // namespace clang