Cache the location of failed typo corrections so that typo correction

isn't repeatedly attempted for the same identifier at the same location.

llvm-svn: 191543

3 files changed, 50 insertions, 29 deletions

diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 56988b1d570..6ac19ae5f75 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -2493,7 +2493,8 @@ public:
                              CorrectionCandidateCallback &CCC,
                              DeclContext *MemberContext = 0,
                              bool EnteringContext = false,
-                             const ObjCObjectPointerType *OPT = 0);
+                             const ObjCObjectPointerType *OPT = 0,
+                             bool RecordFailure = true);
 
   void diagnoseTypo(const TypoCorrection &Correction,
                     const PartialDiagnostic &TypoDiag,
@@ -2705,6 +2706,17 @@ private:
                                            bool receiverIdOrClass,
                                            bool warn, bool instance);
 
+  /// \brief Record the typo correction failure and return an empty correction.
+  TypoCorrection FailedCorrection(IdentifierInfo *Typo, SourceLocation TypoLoc,
+                                  bool RecordFailure = true,
+                                  bool IsUnqualifiedLookup = false) {
+    if (IsUnqualifiedLookup)
+      (void)UnqualifiedTyposCorrected[Typo];
+    if (RecordFailure)
+      TypoCorrectionFailures[Typo].insert(TypoLoc);
+    return TypoCorrection();
+  }
+
 public:
   /// AddInstanceMethodToGlobalPool - All instance methods in a translation
   /// unit are added to a global pool. This allows us to efficiently associate
@@ -6308,6 +6320,14 @@ public:
   /// string represents a keyword.
   UnqualifiedTyposCorrectedMap UnqualifiedTyposCorrected;
 
+  typedef llvm::SmallSet<SourceLocation, 2> SrcLocSet;
+  typedef llvm::DenseMap<IdentifierInfo *, SrcLocSet> IdentifierSourceLocations;
+
+  /// \brief A cache containing identifiers for which typo correction failed and
+  /// their locations, so that repeated attempts to correct an identifier in a
+  /// given location are ignored if typo correction already failed for it.
+  IdentifierSourceLocations TypoCorrectionFailures;
+
   /// \brief Worker object for performing CFG-based warnings.
   sema::AnalysisBasedWarnings AnalysisWarnings;
 
diff --git a/clang/lib/Sema/SemaExprObjC.cpp b/clang/lib/Sema/SemaExprObjC.cpp
index 81d2a8122a1..5550eb8cf9d 100644
--- a/clang/lib/Sema/SemaExprObjC.cpp
+++ b/clang/lib/Sema/SemaExprObjC.cpp
@@ -1839,9 +1839,9 @@ Sema::ObjCMessageKind Sema::getObjCMessageKind(Scope *S,
   }
 
   ObjCInterfaceOrSuperCCC Validator(getCurMethodDecl());
-  if (TypoCorrection Corrected = CorrectTypo(Result.getLookupNameInfo(),
-                                             Result.getLookupKind(), S, NULL,
-                                             Validator)) {
+  if (TypoCorrection Corrected =
+          CorrectTypo(Result.getLookupNameInfo(), Result.getLookupKind(), S,
+                      NULL, Validator, NULL, false, NULL, false)) {
     if (Corrected.isKeyword()) {
       // If we've found the keyword "super" (the only keyword that would be
       // returned by CorrectTypo), this is a send to super.
diff --git a/clang/lib/Sema/SemaLookup.cpp b/clang/lib/Sema/SemaLookup.cpp
index 75b0f984f8c..c2e23c7ede4 100644
--- a/clang/lib/Sema/SemaLookup.cpp
+++ b/clang/lib/Sema/SemaLookup.cpp
@@ -4056,7 +4056,8 @@ TypoCorrection Sema::CorrectTypo(const DeclarationNameInfo &TypoName,
                                  CorrectionCandidateCallback &CCC,
                                  DeclContext *MemberContext,
                                  bool EnteringContext,
-                                 const ObjCObjectPointerType *OPT) {
+                                 const ObjCObjectPointerType *OPT,
+                                 bool RecordFailure) {
   // Always let the ExternalSource have the first chance at correction, even
   // if we would otherwise have given up.
   if (ExternalSource) {
@@ -4095,6 +4096,12 @@ TypoCorrection Sema::CorrectTypo(const DeclarationNameInfo &TypoName,
   if (S && S->isInObjcMethodScope() && Typo == getSuperIdentifier())
     return TypoCorrection();
 
+  // Abort if typo correction already failed for this specific typo.
+  IdentifierSourceLocations::iterator locs = TypoCorrectionFailures.find(Typo);
+  if (locs != TypoCorrectionFailures.end() &&
+      locs->second.count(TypoName.getLoc()) > 0)
+    return TypoCorrection();
+
   NamespaceSpecifierSet Namespaces(Context, CurContext, SS);
 
   TypoCorrectionConsumer Consumer(*this, Typo);
@@ -4193,24 +4200,16 @@ TypoCorrection Sema::CorrectTypo(const DeclarationNameInfo &TypoName,
   AddKeywordsToConsumer(*this, Consumer, S, CCC, SS && SS->isNotEmpty());
 
   // If we haven't found anything, we're done.
-  if (Consumer.empty()) {
-    // If this was an unqualified lookup, note that no correction was found.
-    if (IsUnqualifiedLookup)
-      (void)UnqualifiedTyposCorrected[Typo];
-
-    return TypoCorrection();
-  }
+  if (Consumer.empty())
+    return FailedCorrection(Typo, TypoName.getLoc(), RecordFailure,
+                            IsUnqualifiedLookup);
 
   // Make sure the best edit distance (prior to adding any namespace qualifiers)
   // is not more that about a third of the length of the typo's identifier.
   unsigned ED = Consumer.getBestEditDistance(true);
-  if (ED > 0 && Typo->getName().size() / ED < 3) {
-    // If this was an unqualified lookup, note that no correction was found.
-    if (IsUnqualifiedLookup)
-      (void)UnqualifiedTyposCorrected[Typo];
-
-    return TypoCorrection();
-  }
+  if (ED > 0 && Typo->getName().size() / ED < 3)
+    return FailedCorrection(Typo, TypoName.getLoc(), RecordFailure,
+                            IsUnqualifiedLookup);
 
   // Build the NestedNameSpecifiers for the KnownNamespaces, if we're going
   // to search those namespaces.
@@ -4327,7 +4326,7 @@ retry_lookup:
 
       case LookupResult::Ambiguous:
         // We don't deal with ambiguities.
-        return TypoCorrection();
+        return FailedCorrection(Typo, TypoName.getLoc(), RecordFailure);
 
       case LookupResult::FoundOverloaded: {
         TypoCorrectionConsumer::result_iterator Prev = I;
@@ -4431,7 +4430,8 @@ retry_lookup:
   }
 
   // No corrections remain...
-  if (Consumer.empty()) return TypoCorrection();
+  if (Consumer.empty())
+    return FailedCorrection(Typo, TypoName.getLoc(), RecordFailure);
 
   TypoResultsMap &BestResults = Consumer.getBestResults();
   ED = Consumer.getBestEditDistance(true);
@@ -4440,21 +4440,21 @@ retry_lookup:
     // If this was an unqualified lookup and we believe the callback
     // object wouldn't have filtered out possible corrections, note
     // that no correction was found.
-    if (IsUnqualifiedLookup && !ValidatingCallback)
-      (void)UnqualifiedTyposCorrected[Typo];
-
-    return TypoCorrection();
+    return FailedCorrection(Typo, TypoName.getLoc(), RecordFailure,
+                            IsUnqualifiedLookup && !ValidatingCallback);
   }
 
   // If only a single name remains, return that result.
   if (BestResults.size() == 1) {
     const TypoResultList &CorrectionList = BestResults.begin()->second;
     const TypoCorrection &Result = CorrectionList.front();
-    if (CorrectionList.size() != 1) return TypoCorrection();
+    if (CorrectionList.size() != 1)
+      return FailedCorrection(Typo, TypoName.getLoc(), RecordFailure);
 
     // Don't correct to a keyword that's the same as the typo; the keyword
     // wasn't actually in scope.
-    if (ED == 0 && Result.isKeyword()) return TypoCorrection();
+    if (ED == 0 && Result.isKeyword())
+      return FailedCorrection(Typo, TypoName.getLoc(), RecordFailure);
 
     // Record the correction for unqualified lookup.
     if (IsUnqualifiedLookup)
@@ -4477,7 +4477,8 @@ retry_lookup:
 
     // Don't correct to a keyword that's the same as the typo; the keyword
     // wasn't actually in scope.
-    if (ED == 0) return TypoCorrection();
+    if (ED == 0)
+      return FailedCorrection(Typo, TypoName.getLoc(), RecordFailure);
 
     // Record the correction for unqualified lookup.
     if (IsUnqualifiedLookup)
@@ -4493,7 +4494,7 @@ retry_lookup:
   if (IsUnqualifiedLookup && !ValidatingCallback)
     (void)UnqualifiedTyposCorrected[Typo];
 
-  return TypoCorrection();
+  return FailedCorrection(Typo, TypoName.getLoc(), RecordFailure);
 }
 
 void TypoCorrection::addCorrectionDecl(NamedDecl *CDecl) {