Warning option typo correction: When two options have the same edit_distance don't display either.

Also add a maximum edit distance threshold, so we don't correct "-Wx" to "-W#pragma-messages".

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@144644 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 4 deletions

diff --git a/lib/Basic/DiagnosticIDs.cpp b/lib/Basic/DiagnosticIDs.cpp
index 39fee69adb..cbca8d1c76 100644
--- a/lib/Basic/DiagnosticIDs.cpp
+++ b/lib/Basic/DiagnosticIDs.cpp
@@ -683,7 +683,7 @@ bool DiagnosticIDs::getDiagnosticsInGroup(
 
 StringRef DiagnosticIDs::getNearestWarningOption(StringRef Group) {
   StringRef Best;
-  unsigned BestDistance = 0;
+  unsigned BestDistance = Group.size() + 1; // Sanity threshold.
   for (const WarningOption *i = OptionTable, *e = OptionTable + OptionTableSize;
        i != e; ++i) {
     // Don't suggest ignored warning flags.
@@ -691,9 +691,11 @@ StringRef DiagnosticIDs::getNearestWarningOption(StringRef Group) {
       continue;
 
     unsigned Distance = i->getName().edit_distance(Group, true, BestDistance);
-
-    // Check if this is a better match.
-    if (Best.empty() || Distance < BestDistance) {
+    if (Distance == BestDistance) {
+      // Two matches with the same distance, don't prefer one over the other.
+      Best = "";
+    } else if (Distance < BestDistance) {
+      // This is a better match.
       Best = i->getName();
       BestDistance = Distance;
     }