[analyzer] Use faster hashing (MD5) in CloneDetector.

This replaces the old approach of fingerprinting every AST node into a string,
which avoided collisions and was simple to implement, but turned out to be
extremely ineffective with respect to both performance and memory.

The collisions are now dealt with in a separate pass, which no longer causes
performance problems because collisions are rare.

Patch by Raphael Isemann!

Differential Revision: https://reviews.llvm.org/D22515

llvm-svn: 279378

1 files changed, 0 insertions, 9 deletions

diff --git a/clang/lib/StaticAnalyzer/Checkers/CloneChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/CloneChecker.cpp
index 3b4b78b422a..b4ac223c022 100644
--- a/clang/lib/StaticAnalyzer/Checkers/CloneChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/CloneChecker.cpp
@@ -91,15 +91,6 @@ void CloneChecker::reportClones(SourceManager &SM, AnalysisManager &Mgr,
                                                "Related code clone is here.");
 
   for (CloneDetector::CloneGroup &Group : CloneGroups) {
-    // For readability reasons we sort the clones by line numbers.
-    std::sort(Group.Sequences.begin(), Group.Sequences.end(),
-              [&SM](const StmtSequence &LHS, const StmtSequence &RHS) {
-                return SM.isBeforeInTranslationUnit(LHS.getStartLoc(),
-                                                    RHS.getStartLoc()) &&
-                       SM.isBeforeInTranslationUnit(LHS.getEndLoc(),
-                                                    RHS.getEndLoc());
-              });
-
     // We group the clones by printing the first as a warning and all others
     // as a note.
     DiagEngine.Report(Group.Sequences.front().getStartLoc(), WarnID);