1 files changed, 323 insertions, 45 deletions

diff --git a/lib/CodeGen/CoverageMappingGen.cpp b/lib/CodeGen/CoverageMappingGen.cpp
index a1023473bdd33..89a30dc7040c8 100644
--- a/lib/CodeGen/CoverageMappingGen.cpp
+++ b/lib/CodeGen/CoverageMappingGen.cpp
@@ -29,7 +29,7 @@ using namespace clang;
 using namespace CodeGen;
 using namespace llvm::coverage;
 
-void CoverageSourceInfo::SourceRangeSkipped(SourceRange Range) {
+void CoverageSourceInfo::SourceRangeSkipped(SourceRange Range, SourceLocation) {
   SkippedRanges.push_back(Range);
 }
 
@@ -45,10 +45,19 @@ class SourceMappingRegion {
   /// \brief The region's ending location.
   Optional<SourceLocation> LocEnd;
 
+  /// Whether this region should be emitted after its parent is emitted.
+  bool DeferRegion;
+
+  /// Whether this region is a gap region. The count from a gap region is set
+  /// as the line execution count if there are no other regions on the line.
+  bool GapRegion;
+
 public:
   SourceMappingRegion(Counter Count, Optional<SourceLocation> LocStart,
-                      Optional<SourceLocation> LocEnd)
-      : Count(Count), LocStart(LocStart), LocEnd(LocEnd) {}
+                      Optional<SourceLocation> LocEnd, bool DeferRegion = false,
+                      bool GapRegion = false)
+      : Count(Count), LocStart(LocStart), LocEnd(LocEnd),
+        DeferRegion(DeferRegion), GapRegion(GapRegion) {}
 
   const Counter &getCounter() const { return Count; }
 
@@ -71,6 +80,47 @@ public:
     assert(LocEnd && "Region has no end location");
     return *LocEnd;
   }
+
+  bool isDeferred() const { return DeferRegion; }
+
+  void setDeferred(bool Deferred) { DeferRegion = Deferred; }
+
+  bool isGap() const { return GapRegion; }
+
+  void setGap(bool Gap) { GapRegion = Gap; }
+};
+
+/// Spelling locations for the start and end of a source region.
+struct SpellingRegion {
+  /// The line where the region starts.
+  unsigned LineStart;
+
+  /// The column where the region starts.
+  unsigned ColumnStart;
+
+  /// The line where the region ends.
+  unsigned LineEnd;
+
+  /// The column where the region ends.
+  unsigned ColumnEnd;
+
+  SpellingRegion(SourceManager &SM, SourceLocation LocStart,
+                 SourceLocation LocEnd) {
+    LineStart = SM.getSpellingLineNumber(LocStart);
+    ColumnStart = SM.getSpellingColumnNumber(LocStart);
+    LineEnd = SM.getSpellingLineNumber(LocEnd);
+    ColumnEnd = SM.getSpellingColumnNumber(LocEnd);
+  }
+
+  SpellingRegion(SourceManager &SM, SourceMappingRegion &R)
+      : SpellingRegion(SM, R.getStartLoc(), R.getEndLoc()) {}
+
+  /// Check if the start and end locations appear in source order, i.e
+  /// top->bottom, left->right.
+  bool isInSourceOrder() const {
+    return (LineStart < LineEnd) ||
+           (LineStart == LineEnd && ColumnStart <= ColumnEnd);
+  }
 };
 
 /// \brief Provides the common functionality for the different
@@ -241,12 +291,9 @@ public:
       auto CovFileID = getCoverageFileID(LocStart);
       if (!CovFileID)
         continue;
-      unsigned LineStart = SM.getSpellingLineNumber(LocStart);
-      unsigned ColumnStart = SM.getSpellingColumnNumber(LocStart);
-      unsigned LineEnd = SM.getSpellingLineNumber(LocEnd);
-      unsigned ColumnEnd = SM.getSpellingColumnNumber(LocEnd);
+      SpellingRegion SR{SM, LocStart, LocEnd};
       auto Region = CounterMappingRegion::makeSkipped(
-          *CovFileID, LineStart, ColumnStart, LineEnd, ColumnEnd);
+          *CovFileID, SR.LineStart, SR.ColumnStart, SR.LineEnd, SR.ColumnEnd);
       // Make sure that we only collect the regions that are inside
       // the souce code of this function.
       if (Region.LineStart >= FileLineRanges[*CovFileID].first &&
@@ -284,16 +331,19 @@ public:
       if (Filter.count(std::make_pair(LocStart, LocEnd)))
         continue;
 
-      // Find the spilling locations for the mapping region.
-      unsigned LineStart = SM.getSpellingLineNumber(LocStart);
-      unsigned ColumnStart = SM.getSpellingColumnNumber(LocStart);
-      unsigned LineEnd = SM.getSpellingLineNumber(LocEnd);
-      unsigned ColumnEnd = SM.getSpellingColumnNumber(LocEnd);
-
-      assert(LineStart <= LineEnd && "region start and end out of order");
-      MappingRegions.push_back(CounterMappingRegion::makeRegion(
-          Region.getCounter(), *CovFileID, LineStart, ColumnStart, LineEnd,
-          ColumnEnd));
+      // Find the spelling locations for the mapping region.
+      SpellingRegion SR{SM, LocStart, LocEnd};
+      assert(SR.isInSourceOrder() && "region start and end out of order");
+
+      if (Region.isGap()) {
+        MappingRegions.push_back(CounterMappingRegion::makeGapRegion(
+            Region.getCounter(), *CovFileID, SR.LineStart, SR.ColumnStart,
+            SR.LineEnd, SR.ColumnEnd));
+      } else {
+        MappingRegions.push_back(CounterMappingRegion::makeRegion(
+            Region.getCounter(), *CovFileID, SR.LineStart, SR.ColumnStart,
+            SR.LineEnd, SR.ColumnEnd));
+      }
     }
   }
 
@@ -317,14 +367,11 @@ public:
              "region spans multiple files");
       Filter.insert(std::make_pair(ParentLoc, LocEnd));
 
-      unsigned LineStart = SM.getSpellingLineNumber(ParentLoc);
-      unsigned ColumnStart = SM.getSpellingColumnNumber(ParentLoc);
-      unsigned LineEnd = SM.getSpellingLineNumber(LocEnd);
-      unsigned ColumnEnd = SM.getSpellingColumnNumber(LocEnd);
-
+      SpellingRegion SR{SM, ParentLoc, LocEnd};
+      assert(SR.isInSourceOrder() && "region start and end out of order");
       MappingRegions.push_back(CounterMappingRegion::makeExpansion(
-          *ParentFileID, *ExpandedFileID, LineStart, ColumnStart, LineEnd,
-          ColumnEnd));
+          *ParentFileID, *ExpandedFileID, SR.LineStart, SR.ColumnStart,
+          SR.LineEnd, SR.ColumnEnd));
     }
     return Filter;
   }
@@ -389,6 +436,10 @@ struct CounterCoverageMappingBuilder
   /// \brief A stack of currently live regions.
   std::vector<SourceMappingRegion> RegionStack;
 
+  /// The currently deferred region: its end location and count can be set once
+  /// its parent has been popped from the region stack.
+  Optional<SourceMappingRegion> DeferredRegion;
+
   CounterExpressionBuilder Builder;
 
   /// \brief A location in the most recently visited file or macro.
@@ -397,6 +448,9 @@ struct CounterCoverageMappingBuilder
   /// expressions cross file or macro boundaries.
   SourceLocation MostRecentLocation;
 
+  /// Location of the last terminated region.
+  Optional<std::pair<SourceLocation, size_t>> LastTerminatedRegion;
+
   /// \brief Return a counter for the subtraction of \c RHS from \c LHS
   Counter subtractCounters(Counter LHS, Counter RHS) {
     return Builder.subtract(LHS, RHS);
@@ -424,19 +478,84 @@ struct CounterCoverageMappingBuilder
   /// used with popRegions to exit a "scope", ending the region that was pushed.
   size_t pushRegion(Counter Count, Optional<SourceLocation> StartLoc = None,
                     Optional<SourceLocation> EndLoc = None) {
-    if (StartLoc)
+    if (StartLoc) {
       MostRecentLocation = *StartLoc;
+      completeDeferred(Count, MostRecentLocation);
+    }
     RegionStack.emplace_back(Count, StartLoc, EndLoc);
 
     return RegionStack.size() - 1;
   }
 
+  /// Complete any pending deferred region by setting its end location and
+  /// count, and then pushing it onto the region stack.
+  size_t completeDeferred(Counter Count, SourceLocation DeferredEndLoc) {
+    size_t Index = RegionStack.size();
+    if (!DeferredRegion)
+      return Index;
+
+    // Consume the pending region.
+    SourceMappingRegion DR = DeferredRegion.getValue();
+    DeferredRegion = None;
+
+    // If the region ends in an expansion, find the expansion site.
+    FileID StartFile = SM.getFileID(DR.getStartLoc());
+    if (SM.getFileID(DeferredEndLoc) != StartFile) {
+      if (isNestedIn(DeferredEndLoc, StartFile)) {
+        do {
+          DeferredEndLoc = getIncludeOrExpansionLoc(DeferredEndLoc);
+        } while (StartFile != SM.getFileID(DeferredEndLoc));
+      } else {
+        return Index;
+      }
+    }
+
+    // The parent of this deferred region ends where the containing decl ends,
+    // so the region isn't useful.
+    if (DR.getStartLoc() == DeferredEndLoc)
+      return Index;
+
+    // If we're visiting statements in non-source order (e.g switch cases or
+    // a loop condition) we can't construct a sensible deferred region.
+    if (!SpellingRegion(SM, DR.getStartLoc(), DeferredEndLoc).isInSourceOrder())
+      return Index;
+
+    DR.setGap(true);
+    DR.setCounter(Count);
+    DR.setEndLoc(DeferredEndLoc);
+    handleFileExit(DeferredEndLoc);
+    RegionStack.push_back(DR);
+    return Index;
+  }
+
+  /// Complete a deferred region created after a terminated region at the
+  /// top-level.
+  void completeTopLevelDeferredRegion(Counter Count,
+                                      SourceLocation DeferredEndLoc) {
+    if (DeferredRegion || !LastTerminatedRegion)
+      return;
+
+    if (LastTerminatedRegion->second != RegionStack.size())
+      return;
+
+    SourceLocation Start = LastTerminatedRegion->first;
+    if (SM.getFileID(Start) != SM.getMainFileID())
+      return;
+
+    SourceMappingRegion DR = RegionStack.back();
+    DR.setStartLoc(Start);
+    DR.setDeferred(false);
+    DeferredRegion = DR;
+    completeDeferred(Count, DeferredEndLoc);
+  }
+
   /// \brief Pop regions from the stack into the function's list of regions.
   ///
   /// Adds all regions from \c ParentIndex to the top of the stack to the
   /// function's \c SourceRegions.
   void popRegions(size_t ParentIndex) {
     assert(RegionStack.size() >= ParentIndex && "parent not in stack");
+    bool ParentOfDeferredRegion = false;
     while (RegionStack.size() > ParentIndex) {
       SourceMappingRegion &Region = RegionStack.back();
       if (Region.hasStartLoc()) {
@@ -467,10 +586,34 @@ struct CounterCoverageMappingBuilder
           MostRecentLocation = getIncludeOrExpansionLoc(EndLoc);
 
         assert(SM.isWrittenInSameFile(Region.getStartLoc(), EndLoc));
+        assert(SpellingRegion(SM, Region).isInSourceOrder());
         SourceRegions.push_back(Region);
+
+        if (ParentOfDeferredRegion) {
+          ParentOfDeferredRegion = false;
+
+          // If there's an existing deferred region, keep the old one, because
+          // it means there are two consecutive returns (or a similar pattern).
+          if (!DeferredRegion.hasValue() &&
+              // File IDs aren't gathered within macro expansions, so it isn't
+              // useful to try and create a deferred region inside of one.
+              !EndLoc.isMacroID())
+            DeferredRegion =
+                SourceMappingRegion(Counter::getZero(), EndLoc, None);
+        }
+      } else if (Region.isDeferred()) {
+        assert(!ParentOfDeferredRegion && "Consecutive deferred regions");
+        ParentOfDeferredRegion = true;
       }
       RegionStack.pop_back();
+
+      // If the zero region pushed after the last terminated region no longer
+      // exists, clear its cached information.
+      if (LastTerminatedRegion &&
+          RegionStack.size() < LastTerminatedRegion->second)
+        LastTerminatedRegion = None;
     }
+    assert(!ParentOfDeferredRegion && "Deferred region with no parent");
   }
 
   /// \brief Return the currently active region.
@@ -481,15 +624,17 @@ struct CounterCoverageMappingBuilder
 
   /// \brief Propagate counts through the children of \c S.
   Counter propagateCounts(Counter TopCount, const Stmt *S) {
-    size_t Index = pushRegion(TopCount, getStart(S), getEnd(S));
+    SourceLocation StartLoc = getStart(S);
+    SourceLocation EndLoc = getEnd(S);
+    size_t Index = pushRegion(TopCount, StartLoc, EndLoc);
     Visit(S);
     Counter ExitCount = getRegion().getCounter();
     popRegions(Index);
 
     // The statement may be spanned by an expansion. Make sure we handle a file
     // exit out of this expansion before moving to the next statement.
-    if (SM.isBeforeInTranslationUnit(getStart(S), S->getLocStart()))
-      MostRecentLocation = getEnd(S);
+    if (SM.isBeforeInTranslationUnit(StartLoc, S->getLocStart()))
+      MostRecentLocation = EndLoc;
 
     return ExitCount;
   }
@@ -577,9 +722,11 @@ struct CounterCoverageMappingBuilder
       SourceLocation Loc = MostRecentLocation;
       while (isNestedIn(Loc, ParentFile)) {
         SourceLocation FileStart = getStartOfFileOrMacro(Loc);
-        if (StartLocs.insert(FileStart).second)
+        if (StartLocs.insert(FileStart).second) {
           SourceRegions.emplace_back(*ParentCounter, FileStart,
                                      getEndOfFileOrMacro(Loc));
+          assert(SpellingRegion(SM, SourceRegions.back()).isInSourceOrder());
+        }
         Loc = getIncludeOrExpansionLoc(Loc);
       }
     }
@@ -595,15 +742,53 @@ struct CounterCoverageMappingBuilder
     handleFileExit(StartLoc);
     if (!Region.hasStartLoc())
       Region.setStartLoc(StartLoc);
+
+    completeDeferred(Region.getCounter(), StartLoc);
   }
 
   /// \brief Mark \c S as a terminator, starting a zero region.
   void terminateRegion(const Stmt *S) {
     extendRegion(S);
     SourceMappingRegion &Region = getRegion();
+    SourceLocation EndLoc = getEnd(S);
     if (!Region.hasEndLoc())
-      Region.setEndLoc(getEnd(S));
+      Region.setEndLoc(EndLoc);
     pushRegion(Counter::getZero());
+    auto &ZeroRegion = getRegion();
+    ZeroRegion.setDeferred(true);
+    LastTerminatedRegion = {EndLoc, RegionStack.size()};
+  }
+
+  /// Find a valid gap range between \p AfterLoc and \p BeforeLoc.
+  Optional<SourceRange> findGapAreaBetween(SourceLocation AfterLoc,
+                                           SourceLocation BeforeLoc) {
+    // If the start and end locations of the gap are both within the same macro
+    // file, the range may not be in source order.
+    if (AfterLoc.isMacroID() || BeforeLoc.isMacroID())
+      return None;
+    if (!SM.isWrittenInSameFile(AfterLoc, BeforeLoc))
+      return None;
+    return {{AfterLoc, BeforeLoc}};
+  }
+
+  /// Find the source range after \p AfterStmt and before \p BeforeStmt.
+  Optional<SourceRange> findGapAreaBetween(const Stmt *AfterStmt,
+                                           const Stmt *BeforeStmt) {
+    return findGapAreaBetween(getPreciseTokenLocEnd(getEnd(AfterStmt)),
+                              getStart(BeforeStmt));
+  }
+
+  /// Emit a gap region between \p StartLoc and \p EndLoc with the given count.
+  void fillGapAreaWithCount(SourceLocation StartLoc, SourceLocation EndLoc,
+                            Counter Count) {
+    if (StartLoc == EndLoc)
+      return;
+    assert(SpellingRegion(SM, StartLoc, EndLoc).isInSourceOrder());
+    handleFileExit(StartLoc);
+    size_t Index = pushRegion(Count, StartLoc, EndLoc);
+    getRegion().setGap(true);
+    handleFileExit(EndLoc);
+    popRegions(Index);
   }
 
   /// \brief Keep counts of breaks and continues inside loops.
@@ -617,13 +802,15 @@ struct CounterCoverageMappingBuilder
       CoverageMappingModuleGen &CVM,
       llvm::DenseMap<const Stmt *, unsigned> &CounterMap, SourceManager &SM,
       const LangOptions &LangOpts)
-      : CoverageMappingBuilder(CVM, SM, LangOpts), CounterMap(CounterMap) {}
+      : CoverageMappingBuilder(CVM, SM, LangOpts), CounterMap(CounterMap),
+        DeferredRegion(None) {}
 
   /// \brief Write the mapping data to the output stream
   void write(llvm::raw_ostream &OS) {
     llvm::SmallVector<unsigned, 8> VirtualFileMapping;
     gatherFileIDs(VirtualFileMapping);
     SourceRegionFilter Filter = emitExpansionRegions();
+    assert(!DeferredRegion && "Deferred region never completed");
     emitSourceRegions(Filter);
     gatherSkippedRegions();
 
@@ -644,14 +831,42 @@ struct CounterCoverageMappingBuilder
     handleFileExit(getEnd(S));
   }
 
+  /// Determine whether the final deferred region emitted in \p Body should be
+  /// discarded.
+  static bool discardFinalDeferredRegionInDecl(Stmt *Body) {
+    if (auto *CS = dyn_cast<CompoundStmt>(Body)) {
+      Stmt *LastStmt = CS->body_back();
+      if (auto *IfElse = dyn_cast<IfStmt>(LastStmt)) {
+        if (auto *Else = dyn_cast_or_null<CompoundStmt>(IfElse->getElse()))
+          LastStmt = Else->body_back();
+        else
+          LastStmt = IfElse->getElse();
+      }
+      return dyn_cast_or_null<ReturnStmt>(LastStmt);
+    }
+    return false;
+  }
+
   void VisitDecl(const Decl *D) {
+    assert(!DeferredRegion && "Deferred region never completed");
+
     Stmt *Body = D->getBody();
 
     // Do not propagate region counts into system headers.
     if (Body && SM.isInSystemHeader(SM.getSpellingLoc(getStart(Body))))
       return;
 
-    propagateCounts(getRegionCounter(Body), Body);
+    Counter ExitCount = propagateCounts(getRegionCounter(Body), Body);
+    assert(RegionStack.empty() && "Regions entered but never exited");
+
+    if (DeferredRegion) {
+      // Complete (or discard) any deferred regions introduced by the last
+      // statement.
+      if (discardFinalDeferredRegionInDecl(Body))
+        DeferredRegion = None;
+      else
+        popRegions(completeDeferred(ExitCount, getEnd(Body)));
+    }
   }
 
   void VisitReturnStmt(const ReturnStmt *S) {
@@ -671,10 +886,12 @@ struct CounterCoverageMappingBuilder
   void VisitGotoStmt(const GotoStmt *S) { terminateRegion(S); }
 
   void VisitLabelStmt(const LabelStmt *S) {
+    Counter LabelCount = getRegionCounter(S);
     SourceLocation Start = getStart(S);
+    completeTopLevelDeferredRegion(LabelCount, Start);
     // We can't extendRegion here or we risk overlapping with our new region.
     handleFileExit(Start);
-    pushRegion(getRegionCounter(S), Start);
+    pushRegion(LabelCount, Start);
     Visit(S->getSubStmt());
   }
 
@@ -682,6 +899,8 @@ struct CounterCoverageMappingBuilder
     assert(!BreakContinueStack.empty() && "break not in a loop or switch!");
     BreakContinueStack.back().BreakCount = addCounters(
         BreakContinueStack.back().BreakCount, getRegion().getCounter());
+    // FIXME: a break in a switch should terminate regions for all preceding
+    // case statements, not just the most recent one.
     terminateRegion(S);
   }
 
@@ -692,6 +911,16 @@ struct CounterCoverageMappingBuilder
     terminateRegion(S);
   }
 
+  void VisitCallExpr(const CallExpr *E) {
+    VisitStmt(E);
+
+    // Terminate the region when we hit a noreturn function.
+    // (This is helpful dealing with switch statements.)
+    QualType CalleeType = E->getCallee()->getType();
+    if (getFunctionExtInfo(*CalleeType).getNoReturn())
+      terminateRegion(E);
+  }
+
   void VisitWhileStmt(const WhileStmt *S) {
     extendRegion(S);
 
@@ -710,6 +939,11 @@ struct CounterCoverageMappingBuilder
     propagateCounts(CondCount, S->getCond());
     adjustForOutOfOrderTraversal(getEnd(S));
 
+    // The body count applies to the area immediately after the increment.
+    auto Gap = findGapAreaBetween(S->getCond(), S->getBody());
+    if (Gap)
+      fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(), BodyCount);
+
     Counter OutCount =
         addCounters(BC.BreakCount, subtractCounters(CondCount, BodyCount));
     if (OutCount != ParentCount)
@@ -764,6 +998,12 @@ struct CounterCoverageMappingBuilder
       adjustForOutOfOrderTraversal(getEnd(S));
     }
 
+    // The body count applies to the area immediately after the increment.
+    auto Gap = findGapAreaBetween(getPreciseTokenLocEnd(S->getRParenLoc()),
+                                  getStart(S->getBody()));
+    if (Gap)
+      fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(), BodyCount);
+
     Counter OutCount =
         addCounters(BC.BreakCount, subtractCounters(CondCount, BodyCount));
     if (OutCount != ParentCount)
@@ -783,6 +1023,12 @@ struct CounterCoverageMappingBuilder
     Counter BackedgeCount = propagateCounts(BodyCount, S->getBody());
     BreakContinue BC = BreakContinueStack.pop_back_val();
 
+    // The body count applies to the area immediately after the range.
+    auto Gap = findGapAreaBetween(getPreciseTokenLocEnd(S->getRParenLoc()),
+                                  getStart(S->getBody()));
+    if (Gap)
+      fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(), BodyCount);
+
     Counter LoopCount =
         addCounters(ParentCount, BackedgeCount, BC.ContinueCount);
     Counter OutCount =
@@ -803,6 +1049,12 @@ struct CounterCoverageMappingBuilder
     Counter BackedgeCount = propagateCounts(BodyCount, S->getBody());
     BreakContinue BC = BreakContinueStack.pop_back_val();
 
+    // The body count applies to the area immediately after the collection.
+    auto Gap = findGapAreaBetween(getPreciseTokenLocEnd(S->getRParenLoc()),
+                                  getStart(S->getBody()));
+    if (Gap)
+      fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(), BodyCount);
+
     Counter LoopCount =
         addCounters(ParentCount, BackedgeCount, BC.ContinueCount);
     Counter OutCount =
@@ -823,15 +1075,20 @@ struct CounterCoverageMappingBuilder
     extendRegion(Body);
     if (const auto *CS = dyn_cast<CompoundStmt>(Body)) {
       if (!CS->body_empty()) {
-        // The body of the switch needs a zero region so that fallthrough counts
-        // behave correctly, but it would be misleading to include the braces of
-        // the compound statement in the zeroed area, so we need to handle this
-        // specially.
+        // Make a region for the body of the switch.  If the body starts with
+        // a case, that case will reuse this region; otherwise, this covers
+        // the unreachable code at the beginning of the switch body.
         size_t Index =
-            pushRegion(Counter::getZero(), getStart(CS->body_front()),
-                       getEnd(CS->body_back()));
+            pushRegion(Counter::getZero(), getStart(CS->body_front()));
         for (const auto *Child : CS->children())
           Visit(Child);
+
+        // Set the end for the body of the switch, if it isn't already set.
+        for (size_t i = RegionStack.size(); i != Index; --i) {
+          if (!RegionStack[i - 1].hasEndLoc())
+            RegionStack[i - 1].setEndLoc(getEnd(CS->body_back()));
+        }
+
         popRegions(Index);
       }
     } else
@@ -889,12 +1146,21 @@ struct CounterCoverageMappingBuilder
     // counter for the body when looking at the coverage.
     propagateCounts(ParentCount, S->getCond());
 
+    // The 'then' count applies to the area immediately after the condition.
+    auto Gap = findGapAreaBetween(S->getCond(), S->getThen());
+    if (Gap)
+      fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(), ThenCount);
+
     extendRegion(S->getThen());
     Counter OutCount = propagateCounts(ThenCount, S->getThen());
 
     Counter ElseCount = subtractCounters(ParentCount, ThenCount);
     if (const Stmt *Else = S->getElse()) {
-      extendRegion(S->getElse());
+      // The 'else' count applies to the area immediately after the 'then'.
+      Gap = findGapAreaBetween(S->getThen(), Else);
+      if (Gap)
+        fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(), ElseCount);
+      extendRegion(Else);
       OutCount = addCounters(OutCount, propagateCounts(ElseCount, Else));
     } else
       OutCount = addCounters(OutCount, ElseCount);
@@ -931,25 +1197,34 @@ struct CounterCoverageMappingBuilder
     Visit(E->getCond());
 
     if (!isa<BinaryConditionalOperator>(E)) {
+      // The 'then' count applies to the area immediately after the condition.
+      auto Gap =
+          findGapAreaBetween(E->getQuestionLoc(), getStart(E->getTrueExpr()));
+      if (Gap)
+        fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(), TrueCount);
+
       extendRegion(E->getTrueExpr());
       propagateCounts(TrueCount, E->getTrueExpr());
     }
+
     extendRegion(E->getFalseExpr());
     propagateCounts(subtractCounters(ParentCount, TrueCount),
                     E->getFalseExpr());
   }
 
   void VisitBinLAnd(const BinaryOperator *E) {
-    extendRegion(E);
-    Visit(E->getLHS());
+    extendRegion(E->getLHS());
+    propagateCounts(getRegion().getCounter(), E->getLHS());
+    handleFileExit(getEnd(E->getLHS()));
 
     extendRegion(E->getRHS());
     propagateCounts(getRegionCounter(E), E->getRHS());
   }
 
   void VisitBinLOr(const BinaryOperator *E) {
-    extendRegion(E);
-    Visit(E->getLHS());
+    extendRegion(E->getLHS());
+    propagateCounts(getRegion().getCounter(), E->getLHS());
+    handleFileExit(getEnd(E->getLHS()));
 
     extendRegion(E->getRHS());
     propagateCounts(getRegionCounter(E), E->getRHS());
@@ -992,6 +1267,9 @@ static void dump(llvm::raw_ostream &OS, StringRef FunctionName,
     case CounterMappingRegion::SkippedRegion:
       OS << "Skipped,";
       break;
+    case CounterMappingRegion::GapRegion:
+      OS << "Gap,";
+      break;
     }
 
     OS << "File " << R.FileID << ", " << R.LineStart << ":" << R.ColumnStart