[Coverage] Emit gap region between statements if first statements contains terminate statements.

[zequanwu]

Summary

This solves the problems that D85036 tried to solve, but that patch introduced
new bugs and those bugs should be fixed in the clang coverage rather than
llvm-cov. I'll revert D85036 after this is landed to avoid reintroduce the bugs.

[rnk]

Are the check-profile presubmit test failures related to this patch? Do we have to revert D85036 in the same patch in order to keep the integration tests green?

[zequanwu]

Rebase and fix runtime-counter-relocation.c

Do we have to revert D85036 in the same patch in order to keep the integration tests green?

I didn't revert D85036. I don't know why phabricator thinks I did.

[vsk]

clang/lib/CodeGen/CoverageMappingGen.cpp

559

nit: Whether the visitor is at a ... stmt?

593

Does this mean a deferred gap region following a break; statement won't be completed before the next region is pushed?

942

What's supposed to be the difference between the zero region pushed after a return; vs. after a break;?

1057

Can this replace all of the machinery around DeferredRegions? It'd be nice to just have one way to set up gaps between statements.

[zequanwu]

• Revert the deletion of completeDeferred in pushRegion.
• Emit zero gap region only if OutCounter is different from parentCounter in whil, for statements.
• Update test cases.

[zequanwu]

clang/lib/CodeGen/CoverageMappingGen.cpp

593

I reverted this change.

942

What I think is DeferredRegion is only used for break; and continue. Other terminate statements like return;, throw etc will use the logic in VisitStmt to emit gap region. So, I added this condition to separate the two cases.

1057

See above comments.

[vsk]

clang/lib/CodeGen/CoverageMappingGen.cpp

942

What do you think of the notion of using the gaps inserted in VisitStmt to replace the whole deferred region system? Is it something that might be feasible (if perhaps out of scope for this patch), or do you see a fundamental reason it can't/shouldn't be done?

[zequanwu]

clang/lib/CodeGen/CoverageMappingGen.cpp

942

I think it is feasible. For break and continue, they only affect the statements after them in the same block. For other terminate statements, they affect all the statements after them even outside the block, see example below. Also instead of emitting a zero gap region in VisitStmt, we need emit gap region with (previous counter - current statement counter).

while (cond) {
...
break; // This affects statements' count until the end of the while body.
...
}

while (cond) {
...
return; // This affects statements' count until the end of the function body.
...
}

[vsk]

Thanks for the patient explanation.

clang/lib/CodeGen/CoverageMappingGen.cpp

942

Thanks, that's really helpful. It's clicking now that the main difference is that the deferred region sticks around after we're done visiting a block.

1389

Is the reason why we don't need to complete it because the logic in VisitStmt handles filling in the gap region? What happens if this isn't cleared, or if there are nested switches?

clang/test/CoverageMapping/classtemplate.cpp

83

Nice, this is from the special handling of noreturn calls.

clang/test/CoverageMapping/deferred-region.cpp

19

Nice, this should amount to the same end result, it's a smaller encoding.

43

I'm confused by this change. Do we lose the gap here? I assumed it was needed to prevent the condition count from if (true) from kicking in after the return?

clang/test/CoverageMapping/switch.cpp

62

The blank space after default: break; and before the closing '}' should have the same count as the switch condition, I thought (this goes for all of the unreachable code within a switch body)? The idea is to prevent 'not-executed' regions from appearing after the break stmt.

[zequanwu]

• Deprecate deferred region. Use the notion of gap region inserted in VisitStmt to replace deferred region.
• Emit gap region with OutCounter from last statement if exists.
• Move test cases from deferred-region.cpp to terminate-statements.cpp

clang/test/CoverageMapping/deferred-region.cpp

43

Fixed.

clang/test/CoverageMapping/switch.cpp

62

Yes, they are unreachable. So, shouldn't they always have zero count instead of same count as switch condition?

[vsk]

Thanks, this looks great.

clang/test/CoverageMapping/switch.cpp

62

I see, you're right. We use a gap region with zero count to cover the area after break. That's actually documented here: https://clang.llvm.org/docs/SourceBasedCodeCoverage.html#switch-statements. One interesting point is that there's only one gap region that covers the whole body; in this example, that would be Gap,File 0, [[@LINE]]:13 -> [[@LINE+8]]:10 = 0. So, perhaps the new gaps emitted in switches are redundant, but getting rid of them is just a performance optimization.

[zequanwu]

use itanium abi in terminate-statements.cpp

[zequanwu]

Thanks for reviewing.

clang/test/CoverageMapping/switch.cpp

62

Yes, they are redundant.

[thakis]

This broke ContinuousSyncMode/basic.c in check-profile on macOS (see e.g. end of https://logs.chromium.org/logs/chromium/buildbucket/cr-buildbucket.appspot.com/8853690069583264896/+/steps/package_clang/0/stdout?format=raw), so I reverted it for now.

It repros on my laptop, so let me know if you want me to try things :)

[zequanwu]

In D97101#2603321, @thakis wrote:

This broke ContinuousSyncMode/basic.c in check-profile on macOS (see e.g. end of https://logs.chromium.org/logs/chromium/buildbucket/cr-buildbucket.appspot.com/8853690069583264896/+/steps/package_clang/0/stdout?format=raw), so I reverted it for now.

It repros on my laptop, so let me know if you want me to try things :)

Relanded with update on the broken test case.

clang/lib/CodeGen/CoverageMappingGen.cpp

struct CounterCoverageMappingBuilder
   CounterExpressionBuilder Builder;
 
   /// A location in the most recently visited file or macro.
   ///
   /// This is used to adjust the active source regions appropriately when
   /// expressions cross file or macro boundaries.
   SourceLocation MostRecentLocation;
 
-  /// Location of the last terminated region.
-  Optional<std::pair<SourceLocation, size_t>> LastTerminatedRegion;
+  /// If there is a return, co_return, goto or throw inside.
+  bool HasTerminateStmt = false;
 
   /// Return a counter for the subtraction of \c RHS from \c LHS
   Counter subtractCounters(Counter LHS, Counter RHS) {
     return Builder.subtract(LHS, RHS);
   }
 
   /// Return a counter for the sum of \c LHS and \c RHS.
   Counter addCounters(Counter LHS, Counter RHS) {
struct CounterCoverageMappingBuilder
   /// Returns the index on the stack where the region was pushed. This can be
   /// 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,
                     Optional<Counter> FalseCount = None) {
 
     if (StartLoc && !FalseCount.hasValue()) {
       MostRecentLocation = *StartLoc;
-      completeDeferred(Count, MostRecentLocation);
     }
 
     RegionStack.emplace_back(Count, FalseCount, StartLoc, EndLoc,
                              FalseCount.hasValue());
 
     return RegionStack.size() - 1;
   }
 
   /// Complete any pending deferred region by setting its end location and
size_t completeDeferred(Counter Count, SourceLocation DeferredEndLoc) {
     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);
-  }
-
   size_t locationDepth(SourceLocation Loc) {
     size_t Depth = 0;
     while (Loc.isValid()) {
       Loc = getIncludeOrExpansionLoc(Loc);
       Depth++;
     }
     return Depth;
   }
while (RegionStack.size() > ParentIndex) {
             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");
   }
 
   /// Return the currently active region.
   SourceMappingRegion &getRegion() {
     assert(!RegionStack.empty() && "statement has no region");
     return RegionStack.back();
struct CounterCoverageMappingBuilder
   /// 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(EndLoc);
     pushRegion(Counter::getZero());
+    if (!HasTerminateStmt) {
       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) {
     size_t StartDepth = locationDepth(AfterLoc);
     size_t EndDepth = locationDepth(BeforeLoc);
     while (!SM.isWrittenInSameFile(AfterLoc, BeforeLoc)) {
while (!SM.isWrittenInSameFile(AfterLoc, BeforeLoc)) {
         StartDepth--;
       }
     }
     AfterLoc = getPreciseTokenLocEnd(AfterLoc);
     // 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))
+    if (!SM.isWrittenInSameFile(AfterLoc, BeforeLoc) ||
+        !SpellingRegion(SM, AfterLoc, BeforeLoc).isInSourceOrder())
       return None;
     return {{AfterLoc, BeforeLoc}};
   }
 
   /// 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)
void write(llvm::raw_ostream &OS) {
     CoverageMappingWriter Writer(VirtualFileMapping, Builder.getExpressions(),
                                  MappingRegions);
     Writer.write(OS);
   }
 
   void VisitStmt(const Stmt *S) {
     if (S->getBeginLoc().isValid())
       extendRegion(S);
+    const Stmt *LastStmt = nullptr;
+    bool LastStmtHasTerminateStmt = false;
+    bool SaveTerminateStmt = HasTerminateStmt;
+    HasTerminateStmt = false;
     for (const Stmt *Child : S->children())
-      if (Child)
+      if (Child) {
+        // If last statement contains terminate statements, add a gap area
+        // between the two statements. Skipping attributed statements, because
+        // they don't have valid start location.
+        if (LastStmt && LastStmtHasTerminateStmt &&
+            !dyn_cast<AttributedStmt>(Child)) {
+          auto Gap = findGapAreaBetween(getEnd(LastStmt), getStart(Child));
+          if (Gap)
+            fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(),
+                                 Counter::getZero());
+          LastStmtHasTerminateStmt = false;
+          SaveTerminateStmt = HasTerminateStmt;
+          HasTerminateStmt = false;
+        }
         this->Visit(Child);
+        LastStmt = Child;
+        LastStmtHasTerminateStmt = HasTerminateStmt;
+      }
+    if (SaveTerminateStmt)
+      HasTerminateStmt = true;
     handleFileExit(getEnd(S));
   }
 
   void VisitDecl(const Decl *D) {
     assert(!DeferredRegion && "Deferred region never completed");
 
     Stmt *Body = D->getBody();
 
void VisitDecl(const Decl *D) {
     // or closing braces from being marked as uncovered.
     DeferredRegion = None;
   }
 
   void VisitReturnStmt(const ReturnStmt *S) {
     extendRegion(S);
     if (S->getRetValue())
       Visit(S->getRetValue());
+    HasTerminateStmt = true;
     terminateRegion(S);
   }
 
   void VisitCoroutineBodyStmt(const CoroutineBodyStmt *S) {
     extendRegion(S);
     Visit(S->getBody());
   }
 
   void VisitCoreturnStmt(const CoreturnStmt *S) {
     extendRegion(S);
     if (S->getOperand())
       Visit(S->getOperand());
+    HasTerminateStmt = true;
     terminateRegion(S);
   }
 
   void VisitCXXThrowExpr(const CXXThrowExpr *E) {
     extendRegion(E);
     if (E->getSubExpr())
       Visit(E->getSubExpr());
+    HasTerminateStmt = true;
     terminateRegion(E);
   }
 
-  void VisitGotoStmt(const GotoStmt *S) { terminateRegion(S); }
+  void VisitGotoStmt(const GotoStmt *S) {
+    HasTerminateStmt = true;
+    terminateRegion(S);
+  }
 
   void VisitLabelStmt(const LabelStmt *S) {
     Counter LabelCount = getRegionCounter(S);
     SourceLocation Start = getStart(S);
-    completeTopLevelDeferredRegion(LabelCount, Start);
-    completeDeferred(LabelCount, Start);
     // We can't extendRegion here or we risk overlapping with our new region.
     handleFileExit(Start);
     pushRegion(LabelCount, Start);
     Visit(S->getSubStmt());
   }
 
   void VisitBreakStmt(const BreakStmt *S) {
     assert(!BreakContinueStack.empty() && "break not in a loop or switch!");
struct CounterCoverageMappingBuilder
   }
 
   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())
+    if (getFunctionExtInfo(*CalleeType).getNoReturn()) {
+      HasTerminateStmt = true;
       terminateRegion(E);
     }
+  }
 
   void VisitWhileStmt(const WhileStmt *S) {
     extendRegion(S);
 
     Counter ParentCount = getRegion().getCounter();
     Counter BodyCount = getRegionCounter(S);
 
     // Handle the body first so that we can get the backedge count.
     BreakContinueStack.push_back(BreakContinue());
     extendRegion(S->getBody());
     Counter BackedgeCount = propagateCounts(BodyCount, S->getBody());
     BreakContinue BC = BreakContinueStack.pop_back_val();
 
+    bool BodyHasTerminateStmt = HasTerminateStmt;
+    HasTerminateStmt = false;
+
     // Go back to handle the condition.
     Counter CondCount =
         addCounters(ParentCount, BackedgeCount, BC.ContinueCount);
     propagateCounts(CondCount, S->getCond());
     adjustForOutOfOrderTraversal(getEnd(S));
 
     // The body count applies to the area immediately after the increment.
     auto Gap = findGapAreaBetween(S->getRParenLoc(), getStart(S->getBody()));
     if (Gap)
       fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(), BodyCount);
 
     Counter OutCount =
         addCounters(BC.BreakCount, subtractCounters(CondCount, BodyCount));
     if (OutCount != ParentCount)
       pushRegion(OutCount);
 
     // Create Branch Region around condition.
     createBranchRegion(S->getCond(), BodyCount,
                        subtractCounters(CondCount, BodyCount));
+
+    if (BodyHasTerminateStmt)
+      HasTerminateStmt = true;
   }
 
   void VisitDoStmt(const DoStmt *S) {
     extendRegion(S);
 
     Counter ParentCount = getRegion().getCounter();
     Counter BodyCount = getRegionCounter(S);
 
     BreakContinueStack.push_back(BreakContinue());
     extendRegion(S->getBody());
     Counter BackedgeCount =
         propagateCounts(addCounters(ParentCount, BodyCount), S->getBody());
     BreakContinue BC = BreakContinueStack.pop_back_val();
 
+    bool BodyHasTerminateStmt = HasTerminateStmt;
+    HasTerminateStmt = false;
+
     Counter CondCount = addCounters(BackedgeCount, BC.ContinueCount);
     propagateCounts(CondCount, S->getCond());
 
     Counter OutCount =
         addCounters(BC.BreakCount, subtractCounters(CondCount, BodyCount));
     if (OutCount != ParentCount)
       pushRegion(OutCount);
 
     // Create Branch Region around condition.
     createBranchRegion(S->getCond(), BodyCount,
                        subtractCounters(CondCount, BodyCount));
+
+    if (BodyHasTerminateStmt)
+      HasTerminateStmt = true;
   }
 
   void VisitForStmt(const ForStmt *S) {
     extendRegion(S);
     if (S->getInit())
       Visit(S->getInit());
 
     Counter ParentCount = getRegion().getCounter();
     Counter BodyCount = getRegionCounter(S);
 
     // The loop increment may contain a break or continue.
     if (S->getInc())
       BreakContinueStack.emplace_back();
 
     // Handle the body first so that we can get the backedge count.
     BreakContinueStack.emplace_back();
     extendRegion(S->getBody());
     Counter BackedgeCount = propagateCounts(BodyCount, S->getBody());
     BreakContinue BodyBC = BreakContinueStack.pop_back_val();
 
+    bool BodyHasTerminateStmt = HasTerminateStmt;
+    HasTerminateStmt = false;
+
     // The increment is essentially part of the body but it needs to include
     // the count for all the continue statements.
     BreakContinue IncrementBC;
     if (const Stmt *Inc = S->getInc()) {
       propagateCounts(addCounters(BackedgeCount, BodyBC.ContinueCount), Inc);
       IncrementBC = BreakContinueStack.pop_back_val();
     }
 
void VisitForStmt(const ForStmt *S) {
     Counter OutCount = addCounters(BodyBC.BreakCount, IncrementBC.BreakCount,
                                    subtractCounters(CondCount, BodyCount));
     if (OutCount != ParentCount)
       pushRegion(OutCount);
 
     // Create Branch Region around condition.
     createBranchRegion(S->getCond(), BodyCount,
                        subtractCounters(CondCount, BodyCount));
+
+    if (BodyHasTerminateStmt)
+      HasTerminateStmt = true;
   }
 
   void VisitCXXForRangeStmt(const CXXForRangeStmt *S) {
     extendRegion(S);
     if (S->getInit())
       Visit(S->getInit());
     Visit(S->getLoopVarStmt());
     Visit(S->getRangeStmt());
 
     Counter ParentCount = getRegion().getCounter();
     Counter BodyCount = getRegionCounter(S);
 
     BreakContinueStack.push_back(BreakContinue());
     extendRegion(S->getBody());
     Counter BackedgeCount = propagateCounts(BodyCount, S->getBody());
     BreakContinue BC = BreakContinueStack.pop_back_val();
 
+    bool BodyHasTerminateStmt = HasTerminateStmt;
+    HasTerminateStmt = false;
+
     // The body count applies to the area immediately after the range.
     auto Gap = findGapAreaBetween(S->getRParenLoc(), getStart(S->getBody()));
     if (Gap)
       fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(), BodyCount);
 
     Counter LoopCount =
         addCounters(ParentCount, BackedgeCount, BC.ContinueCount);
     Counter OutCount =
         addCounters(BC.BreakCount, subtractCounters(LoopCount, BodyCount));
     if (OutCount != ParentCount)
       pushRegion(OutCount);
 
     // Create Branch Region around condition.
     createBranchRegion(S->getCond(), BodyCount,
                        subtractCounters(LoopCount, BodyCount));
+
+    if (BodyHasTerminateStmt)
+      HasTerminateStmt = true;
   }
 
   void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S) {
     extendRegion(S);
     Visit(S->getElement());
 
     Counter ParentCount = getRegion().getCounter();
     Counter BodyCount = getRegionCounter(S);
void VisitSwitchStmt(const SwitchStmt *S) {
     extendRegion(Body);
     if (const auto *CS = dyn_cast<CompoundStmt>(Body)) {
       if (!CS->body_empty()) {
         // 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));
         getRegion().setGap(true);
-        for (const auto *Child : CS->children())
-          Visit(Child);
+        Visit(Body);
 
         // 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
       propagateCounts(Counter::getZero(), Body);
     BreakContinue BC = BreakContinueStack.pop_back_val();
 
     if (!BreakContinueStack.empty())
       BreakContinueStack.back().ContinueCount = addCounters(
           BreakContinueStack.back().ContinueCount, BC.ContinueCount);
 
     Counter ParentCount = getRegion().getCounter();
     Counter ExitCount = getRegionCounter(S);
     SourceLocation ExitLoc = getEnd(S);
     pushRegion(ExitCount);
 
     // Ensure that handleFileExit recognizes when the end location is located
     // in a different file.
     MostRecentLocation = getStart(S);
     handleFileExit(ExitLoc);
 
     // Create a Branch Region around each Case. Subtract the case's
     // counter from the Parent counter to track the "False" branch count.
     Counter CaseCountSum;
     bool HasDefaultCase = false;
     const SwitchCase *Case = S->getSwitchCaseList();
void VisitIfStmt(const IfStmt *S) {
     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()) {
+      bool ThenHasTerminateStmt = HasTerminateStmt;
+      HasTerminateStmt = false;
+
       // The 'else' count applies to the area immediately after the 'then'.
       Gap = findGapAreaBetween(getEnd(S->getThen()), getStart(Else));
       if (Gap)
         fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(), ElseCount);
       extendRegion(Else);
       OutCount = addCounters(OutCount, propagateCounts(ElseCount, Else));
+
+      if (ThenHasTerminateStmt)
+        HasTerminateStmt = true;
     } else
       OutCount = addCounters(OutCount, ElseCount);
 
     if (OutCount != ParentCount)
       pushRegion(OutCount);
 
     // Create Branch Region around condition.
     createBranchRegion(S->getCond(), ThenCount,

clang/test/CoverageMapping/classtemplate.cpp

struct map {
   map(initializer_list<T> i, const string &s = string()) {}
   ~map() { abort(); }
 };
 
 }; // namespace std
 
 // CHECK-INIT-LIST-LABEL: _Z5Test4v:
 std::map<int, int> Test4() { // CHECK-INIT-LIST: File 0, [[@LINE]]:28 -> [[@LINE+3]]:2 = #0
-  abort();
+  abort();                           // CHECK-INIT-LIST-NEXT: Gap,File 0, [[@LINE]]:11 -> [[@LINE+1]]:3 = 0
   return std::map<int, int>{{0, 0}}; // CHECK-INIT-LIST-NEXT: [[@LINE]]:3 -> [[@LINE]]:36 = 0
 }
 
 int main() {
   Test<unsigned> t;
   t.set(Test<unsigned>::A, 5.5);
   t.set(Test<unsigned>::T, 5.6);
   t.set(Test<unsigned>::G, 5.7);
   t.set(Test<unsigned>::C, 5.8);
   Test4();
   return 0;
 }

clang/test/CoverageMapping/coroutine.cpp

 // CHECK-LABEL: _Z2f1i:
 int f1(int x) {       // CHECK-NEXT: File 0, [[@LINE]]:15 -> [[@LINE+8]]:2 = #0
   if (x > 42) {       // CHECK-NEXT: File 0, [[@LINE]]:7 -> [[@LINE]]:13 = #0
                       // CHECK-NEXT: Branch,File 0, [[@LINE-1]]:7 -> [[@LINE-1]]:13 = #1, (#0 - #1)
     ++x;              // CHECK-NEXT: Gap,File 0, [[@LINE-2]]:14 -> [[@LINE-2]]:15 = #1
   } else {            // CHECK-NEXT: File 0, [[@LINE-3]]:15 -> [[@LINE]]:4 = #1
     co_return x + 42; // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:4 -> [[@LINE-1]]:10 = (#0 - #1)
   }                   // CHECK-NEXT: File 0, [[@LINE-2]]:10 -> [[@LINE]]:4 = (#0 - #1)
-  co_return x;        // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:4 -> [[@LINE]]:3 = #1
-} // CHECK-NEXT: File 0, [[@LINE-1]]:3 -> [[@LINE]]:2 = #1
+  co_return x;        // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:4 -> [[@LINE]]:3 = 0
+} // CHECK-NEXT: File 0, [[@LINE-1]]:3 -> [[@LINE-1]]:14 = #1

clang/test/CoverageMapping/deferred-region.cpp

if (x == 0) {
     //< Don't complete the last deferred region in a decl, even though it may
     //< leave some whitespace marked with the same counter as the final return.
 }
 
 // CHECK-LABEL: _Z4foooi:
 void fooo(int x) {
   if (x == 0) {
     return;
-  } // CHECK: Gap,File 0, [[@LINE]]:4 -> [[@LINE+2]]:3 = (#0 - #1)
+  } // CHECK: Gap,File 0, [[@LINE]]:4 -> [[@LINE+2]]:3 = 0
 
   if (x == 1) {
     return;
   } // CHECK-NOT: Gap,File 0, [[@LINE]]:4
 
 }
 
 // CHECK-LABEL: _Z3bazv:
 void baz() { // CHECK: [[@LINE]]:12 -> [[@LINE+2]]:2
   return;    // CHECK-NOT: File
 }
 
 // CHECK-LABEL: _Z3mazv:
 void maz() {
   if (true)
-    return; // CHECK: Gap,File 0, [[@LINE]]:11 -> [[@LINE+2]]:3 = (#0 - #1)
+    return; // CHECK: Gap,File 0, [[@LINE]]:12 -> [[@LINE+2]]:3 = 0
 
   return; // CHECK-NOT: Gap
 }
 
 // CHECK-LABEL: _Z4maazv:
 void maaz() {
   if (true)
-    return; // CHECK: Gap,File 0, [[@LINE]]:11
+    return;
   else
     return; // CHECK-NOT: Gap,File 0, [[@LINE]]
 }
 
 // CHECK-LABEL: _Z5maaazv:
 void maaaz() {
   if (true) {
     return;
-  } else {  // CHECK: Gap,File 0, [[@LINE]]:4 -> [[@LINE]]:10
+  } else {
     return; // CHECK-NOT: Gap,File 0, [[@LINE]]
   }
 }
 
 // CHECK-LABEL: _Z3bari:
 void bar(int x) {
   IF (x)
-    return; // CHECK: Gap,File 0, [[@LINE]]:11 -> [[@LINE+2]]:3 = (#0 - #1)
+    return; // CHECK: Gap,File 0, [[@LINE]]:12 -> [[@LINE+2]]:3 = 0
 
   IF (!x)
-    return; // CHECK: Gap,File 0, [[@LINE]]:11 -> [[@LINE+2]]:3 = ((#0 - #1) - #2)
+    return; // CHECK: Gap,File 0, [[@LINE]]:12 -> [[@LINE+2]]:3 = 0
 
   foo(x);
 }
 
 // CHECK-LABEL: _Z4quuxi:
 // Deferred regions are not emitted within macro expansions.
 void quux(int x) {
   STMT(
void quux(int x) {
   )
 }
 
 // CHECK-LABEL: _Z8weird_ifv:
 void weird_if() {
   int i = 0;
 
   if (false)
-    return; // CHECK: Gap,File 0, [[@LINE]]:11 -> [[@LINE+2]]:3 = (#0 - #1)
+    return; // CHECK: Gap,File 0, [[@LINE]]:12 -> [[@LINE+2]]:3 = 0
 
   if (false)
     i++;
 
   if (i + 100 > 0) { // CHECK: [[@LINE]]:20 -> [[@LINE+6]]:4 = #3
     if (false)       // CHECK: [[@LINE+1]]:7 -> [[@LINE+1]]:13 = #4
-      return;        // CHECK: Gap,File 0, [[@LINE]]:13 -> [[@LINE+2]]:5 = (#3 - #4)
-                     // CHECK: [[@LINE+1]]:5 -> [[@LINE+3]]:4 = (#3 - #4)
-    return;          // CHECK: Gap,File 0, [[@LINE]]:5 -> [[@LINE+4]]:3 = ((#0 - #1) - #3)
+      return;        // CHECK: Gap,File 0, [[@LINE]]:14 -> [[@LINE+2]]:5 = 0
+                     // CHECK: [[@LINE+1]]:5 -> [[@LINE+1]]:11 = (#3 - #4)
+    return;
 
-  }
+  }                  // CHECK: Gap,File 0, [[@LINE]]:4 -> [[@LINE+2]]:3 = 0
 
   if (false)
     return; // CHECK-NOT: Gap,File 0, [[@LINE]]:11
 }
 
 // CHECK-LABEL: _Z8for_loopv:
 void for_loop() {
   if (false)
-    return; // CHECK: Gap,File 0, [[@LINE]]:11 -> [[@LINE+2]]:3 = (#0 - #1)
+    return; // CHECK: Gap,File 0, [[@LINE]]:12 -> [[@LINE+2]]:3 = 0
 
   for (int i = 0; i < 10; ++i) {
     if (i % 2 == 0)
       continue; // CHECK: Gap,File 0, [[@LINE]]:15 -> [[@LINE+2]]:5 = (#2 - #3)
 
     if (i % 5 == 0)
       break; // CHECK: Gap,File 0, [[@LINE]]:12 -> [[@LINE+2]]:5 = ((#2 - #3) - #4)
 
     int x = i; // CHECK: [[@LINE]]:5 -> [[@LINE+3]]:4 = ((#2 - #3) - #4)
     return; // CHECK-NOT: [[@LINE]]:11 -> [[@LINE+2]]
 
   }
 }
 
 struct Error {};
 
 // CHECK-LABEL: _Z10while_loopv:
 void while_loop() {
   if (false)
-    return; // CHECK: Gap,File 0, [[@LINE]]:11 -> [[@LINE+2]]:3 = (#0 - #1)
+    return; // CHECK: Gap,File 0, [[@LINE]]:12 -> [[@LINE+2]]:3 = 0
 
   int x = 0;
   while (++x < 10) {
     if (x == 1)
       continue; // CHECK: Gap,File 0, [[@LINE]]:15 -> [[@LINE+2]]:5 = (#2 - #3)
 
     while (++x < 4) {
       if (x == 3)
         break; // CHECK: Gap,File 0, [[@LINE]]:14 -> [[@LINE+2]]:7 = (#4 - #5)
 
       while (++x < 5) {}
     }
 
     if (x == 0)
-      throw Error(); // CHECK: Gap,File 0, [[@LINE]]:20 -> [[@LINE+2]]:5 = ((#2 - #3) - #7)
+      throw Error(); // CHECK: Gap,File 0, [[@LINE]]:21 -> [[@LINE+2]]:5 = 0
 
     while (++x < 9) {
       if (x == 0)
         break; // CHECK-NOT: [[@LINE]]:14 -> [[@LINE+2]]
 
     }
   }
 }
 
 // CHECK-LABEL: _Z5gotosv:
 void gotos() {
   if (false)
-    goto out; // CHECK: Gap,File 0, [[@LINE]]:13 -> [[@LINE+2]]:3 = (#0 - #1)
+    goto out; // CHECK: Gap,File 0, [[@LINE]]:14 -> [[@LINE+2]]:3 = 0
 
-  return; // CHECK: [[@LINE]]:3 -> [[@LINE+4]]:2 = (#0 - #1)
+  return; // CHECK: [[@LINE]]:3 -> [[@LINE]]:9 = (#0 - #1)
 
 out:
   return; // CHECK-NOT: Gap,File 0, [[@LINE]]:8
 }
 
 // CHECK-LABEL: _Z8switchesv:
 void switches() {
   int x;
   switch (x) {
     case 0:
       return;
     default:
       return; // CHECK-NOT: Gap,File 0, [[@LINE]]
   }
 }
 
 #include "deferred-region-helper.h"
 // CHECK-LABEL: _Z13included_funcv:
 // CHECK:  Gap,File 0, 2:13 -> 3:5 = #1
-// CHECK:  Gap,File 0, 3:11 -> 4:3 = (#0 - #1)
+// CHECK:  Gap,File 0, 3:12 -> 4:3 = 0
 
 // CHECK-LABEL: _Z7includev:
 void include() {
   included_func();
 }
 
 int main() {
   foo(0);

clang/test/CoverageMapping/label.cpp

 // RUN: %clang_cc1 -mllvm -emptyline-comment-coverage=false -fprofile-instrument=clang -fcoverage-mapping -dump-coverage-mapping -emit-llvm-only -main-file-name label.cpp %s | FileCheck %s
 
 // CHECK: func
 void func() {                // CHECK-NEXT: File 0, [[@LINE]]:13 -> {{[0-9]+}}:2 = #0
   int i = 0;                 // CHECK-NEXT: File 0, [[@LINE+3]]:14 -> [[@LINE+3]]:20 = (#0 + #3)
                              // CHECK-NEXT: Branch,File 0, [[@LINE+2]]:14 -> [[@LINE+2]]:20 = #1, ((#0 + #3) - #1)
                              // CHECK-NEXT: File 0, [[@LINE+1]]:22 -> [[@LINE+1]]:25 = #3
   for(i = 0; i < 10; ++i) {  // CHECK: File 0, [[@LINE]]:27 -> [[@LINE+11]]:4 = #1
                              // CHECK-NEXT: File 0, [[@LINE+1]]:8 -> [[@LINE+1]]:13 = #1
     if(i < 5) {              // CHECK: File 0, [[@LINE]]:15 -> [[@LINE+6]]:6 = #2
       {
         x:                   // CHECK-NEXT: File 0, [[@LINE]]:9 -> [[@LINE+4]]:6 = #3
           int j = 1;
       }
       int m = 2;
-    } else
-      goto x;                // CHECK: File 0, [[@LINE]]:7 -> [[@LINE]]:13 = (#1 - #2)
-    int k = 3;               // CHECK-NEXT: File 0, [[@LINE-1]]:13 -> [[@LINE]]:5 = #3
-  }                          // CHECK-NEXT: File 0, [[@LINE-1]]:5 -> [[@LINE]]:4 = #3
+    } else                   // CHECK: File 0, [[@LINE+1]]:7 -> [[@LINE+1]]:13 = (#1 - #2)
+      goto x;                // CHECK-NEXT: Gap,File 0, [[@LINE]]:14 -> [[@LINE+1]]:5 = 0
+    int k = 3;               // CHECK-NEXT: File 0, [[@LINE]]:5 -> [[@LINE+1]]:4 = #3
+  }                          // CHECK-NEXT: Gap,File 0, [[@LINE]]:4 -> [[@LINE+1]]:3 = 0
   static int j = 0;          // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+4]]:2 = ((#0 + #3) - #1)
   ++j;
   if(j == 1)                 // CHECK-NEXT: File 0, [[@LINE]]:6 -> [[@LINE]]:12 = ((#0 + #3) - #1)
     goto x;                  // CHECK: File 0, [[@LINE]]:5 -> [[@LINE]]:11 = #4
 }
 
                              // CHECK-NEXT: test1
 void test1(int x) {          // CHECK-NEXT: File 0, [[@LINE]]:19 -> {{[0-9]+}}:2 = #0
   if(x == 0)                 // CHECK-NEXT: File 0, [[@LINE]]:6 -> [[@LINE]]:12 = #0
     goto a;                  // CHECK: File 0, [[@LINE]]:5 -> [[@LINE]]:11 = #1
-                             // CHECK-NEXT: File 0, [[@LINE-1]]:11 -> [[@LINE+1]]:3 = (#0 - #1)
-  goto b;                    // CHECK: File 0, [[@LINE]]:3 -> [[@LINE+5]]:2 = (#0 - #1)
-                             // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:9 -> [[@LINE+1]]:1 = #2
+                             // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:12 -> [[@LINE+1]]:3 = 0
+  goto b;                    // CHECK: File 0, [[@LINE]]:3 -> [[@LINE]]:9 = (#0 - #1)
+                             // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:10 -> [[@LINE+1]]:1 = 0
 a:                           // CHECK-NEXT: File 0, [[@LINE]]:1 -> [[@LINE+3]]:2 = #2
 b:                           // CHECK-NEXT: File 0, [[@LINE]]:1 -> [[@LINE+2]]:2 = #3
   x = x + 1;
 }
 
                              // CHECK-NEXT: test2
 void test2(int x) {          // CHECK-NEXT: File 0, [[@LINE]]:19 -> {{[0-9]+}}:2 = #0
   if(x == 0)                 // CHECK-NEXT: File 0, [[@LINE]]:6 -> [[@LINE]]:12 = #0
     goto a;                  // CHECK: File 0, [[@LINE]]:5 -> [[@LINE]]:11 = #1
-                             // CHECK: Gap,File 0, [[@LINE-1]]:12 -> [[@LINE+3]]:8 = (#0 - #1)
+                             // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:12 -> [[@LINE+3]]:8 = (#0 - #1)
                              // CHECK-NEXT: File 0, [[@LINE+2]]:8 -> [[@LINE+3]]:11 = (#0 - #1)
                              // CHECK-NEXT: File 0, [[@LINE+1]]:11 -> [[@LINE+1]]:17 = (#0 - #1)
   else if(x == 1)            // CHECK: File 0, [[@LINE+1]]:5 -> [[@LINE+1]]:11 = #2
-    goto b;                  // CHECK-NEXT: File 0, [[@LINE]]:11 -> [[@LINE+1]]:1 = #3
+    goto b;                  // CHECK-NEXT: Gap,File 0, [[@LINE]]:12 -> [[@LINE+1]]:1 = 0
 a:                           // CHECK-NEXT: File 0, [[@LINE]]:1 -> [[@LINE+3]]:2 = #3
 b:                           // CHECK-NEXT: File 0, [[@LINE]]:1 -> [[@LINE+2]]:2 = #4
   x = x + 1;
 }
 
 // CHECK-NEXT: test3
 #define a b
 void test3() {
   if (0)
-    goto b; // CHECK: Gap,File 0, [[@LINE]]:11 -> [[@LINE+1]]:1 = [[retnCount:#[0-9]+]]
-a: // CHECK-NEXT: Expansion,File 0, [[@LINE]]:1 -> [[@LINE]]:2 = [[retnCount]] (Expanded file = 1)
+    goto b; // CHECK: Gap,File 0, [[@LINE]]:12 -> [[@LINE+1]]:1 = 0
+a: // CHECK-NEXT: Expansion,File 0, [[@LINE]]:1 -> [[@LINE]]:2 = [[retnCount:#[0-9]+]] (Expanded file = 1)
   return; // CHECK-NEXT: File 0, [[@LINE-1]]:2 -> [[@LINE]]:9 = [[retnCount]]
 }
 #undef a
 
                              // CHECK: main
 int main() {                 // CHECK-NEXT: File 0, [[@LINE]]:12 -> {{[0-9]+}}:2 = #0
   int j = 0;
   for(int i = 0; i < 10; ++i) { // CHECK: File 0, [[@LINE]]:31 -> [[@LINE+13]]:4 = #1
   a:                         // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+12]]:4 = #2
     if(i < 3)                // CHECK-NEXT: File 0, [[@LINE]]:8 -> [[@LINE]]:13 = #2
       goto e;                // CHECK: File 0, [[@LINE]]:7 -> [[@LINE]]:13 = #3
-                             // CHECK-NEXT: File 0, [[@LINE-1]]:13 -> [[@LINE+1]]:5 = (#2 - #3)
-    goto c;                  // CHECK-NEXT: File 0, [[@LINE]]:5 -> [[@LINE+8]]:4 = (#2 - #3)
-                             // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:11 -> [[@LINE+1]]:3 = #4
+                             // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:14 -> [[@LINE+1]]:5 = 0
+    goto c;                  // CHECK-NEXT: File 0, [[@LINE]]:5 -> [[@LINE]]:11 = (#2 - #3)
+                             // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:12 -> [[@LINE+1]]:3 = 0
   b:                         // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+6]]:4 = #4
     j = 2;
   c:                         // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+4]]:4 = #5
     j = 1;
                              // CHECK-NEXT: File 0, [[@LINE+1]]:3 -> [[@LINE+2]]:4 = #6
   e: f: ;                    // CHECK-NEXT: File 0, [[@LINE]]:6 -> [[@LINE+1]]:4 = #7
-  }
+  }                          // CHECK-NEXT: Gap,File 0, [[@LINE]]:4 -> [[@LINE+1]]:3 = 0
   func();                    // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+3]]:2 = ((#0 + #7) - #1)
   test1(0);
   test2(2);
 }

clang/test/CoverageMapping/moremacros.c

int main(int argc, const char *argv[]) {
   // CHECK-NEXT: File 0, [[@LINE+5]]:7 -> [[@LINE+5]]:12 = #0
   // CHECK-NEXT: Branch,File 0, [[@LINE+4]]:7 -> [[@LINE+4]]:12 = #2, (#0 - #2)
   // CHECK-NEXT: Gap,File 0, [[@LINE+3]]:13 -> [[@LINE+3]]:14 = #2
   // CHECK-NEXT: Expansion,File 0, [[@LINE+2]]:14 -> [[@LINE+2]]:19 = #2
   // CHECK-NEXT: File 0, [[@LINE+1]]:19 -> [[@LINE+4]]:8 = #2
   if (!argc) LBRAC
     return 0;
   // CHECK-NEXT: Expansion,File 0, [[@LINE+1]]:3 -> [[@LINE+1]]:8 = #2
-  RBRAC // CHECK-NEXT: [[@LINE]]:8 -> [[@LINE+8]]:3 = (#0 - #2)
+  RBRAC // CHECK-NEXT: [[@LINE]]:8 -> [[@LINE+8]]:3 = 0
 
   // CHECK-NEXT: File 0, [[@LINE+6]]:3 -> [[@LINE+17]]:2 = (#0 - #2)
   // CHECK-NEXT: File 0, [[@LINE+5]]:7 -> [[@LINE+5]]:12 = (#0 - #2)
   // CHECK-NEXT: Branch,File 0, [[@LINE+4]]:7 -> [[@LINE+4]]:12 = #3, ((#0 - #2) - #3)
   // CHECK-NEXT: Gap,File 0, [[@LINE+3]]:13 -> [[@LINE+3]]:14 = #3
   // CHECK-NEXT: Expansion,File 0, [[@LINE+2]]:14 -> [[@LINE+2]]:19 = #3
   // CHECK-NEXT: File 0, [[@LINE+1]]:19 -> [[@LINE+3]]:4 = #3
   if (!argc) LBRAC
     return 0;
-  } // CHECK-NEXT: [[@LINE]]:4 -> [[@LINE+5]]:3 = ((#0 - #2) - #3)
+  } // CHECK-NEXT: [[@LINE]]:4 -> [[@LINE+5]]:3 = 0
 
   // CHECK-NEXT: File 0, [[@LINE+3]]:3 -> [[@LINE+7]]:2 = ((#0 - #2) - #3)
   // CHECK-NEXT: File 0, [[@LINE+2]]:7 -> [[@LINE+2]]:12 = ((#0 - #2) - #3)
   // CHECK: File 0, [[@LINE+1]]:14 -> [[@LINE+4]]:8 = #4
   if (!argc) {
     return 0;
   // CHECK-NEXT: Expansion,File 0, [[@LINE+1]]:3 -> [[@LINE+1]]:8 = #4
   RBRAC
 }
 
 // CHECK-NEXT: File 1, 3:15 -> 3:16 = #2
 // CHECK-NEXT: File 2, 4:15 -> 4:16 = #2
 // CHECK-NEXT: File 3, 3:15 -> 3:16 = #3
 // CHECK-NEXT: File 4, 4:15 -> 4:16 = #4

clang/test/CoverageMapping/return.c

 // RUN: %clang_cc1 -mllvm -emptyline-comment-coverage=false -fprofile-instrument=clang -fcoverage-mapping -dump-coverage-mapping -emit-llvm-only -main-file-name return.c %s | FileCheck %s
 
 // CHECK: func
 void func() {                   // CHECK: File 0, [[@LINE]]:13 -> [[@LINE+3]]:2 = #0
-  return;
+  return;                       // CHECK-NEXT: Gap,File 0, [[@LINE]]:10 -> [[@LINE+1]]:3 = 0
   int i = 0;                    // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:2 = 0
 }
 
                                 // CHECK-NEXT: func2
 void func2() {                  // CHECK-NEXT: File 0, [[@LINE]]:14 -> {{[0-9]+}}:2 = #0
                                 // CHECK-NEXT: File 0, [[@LINE+3]]:18 -> [[@LINE+3]]:24 = ((#0 + #1) - #2)
                                 // CHECK-NEXT: Branch,File 0, [[@LINE+2]]:18 -> [[@LINE+2]]:24 = #1, (#0 - #2)
                                 // CHECK-NEXT: File 0, [[@LINE+1]]:26 -> [[@LINE+1]]:29 = (#1 - #2)
   for(int i = 0; i < 10; ++i) { // CHECK: File 0, [[@LINE]]:31 -> {{[0-9]+}}:4 = #1
                                 // CHECK-NEXT: File 0, [[@LINE+1]]:8 -> [[@LINE+1]]:13 = #1
     if(i > 2) {                 // CHECK: File 0, [[@LINE]]:15 -> [[@LINE+2]]:6 = #2
-      return;                   // CHECK-NEXT: File 0, [[@LINE+1]]:6 -> [[@LINE+3]]:5 = (#1 - #2)
+      return;                   // CHECK-NEXT: Gap,File 0, [[@LINE+1]]:6 -> [[@LINE+3]]:5 = 0
     }                           // CHECK-NEXT: File 0, [[@LINE+2]]:5 -> {{[0-9]+}}:4 = (#1 - #2)
                                 // CHECK-NEXT: File 0, [[@LINE+1]]:8 -> [[@LINE+1]]:14 = (#1 - #2)
     if(i == 3) {                // CHECK: File 0, [[@LINE]]:16 -> [[@LINE+2]]:6 = #3
       int j = 1;
     } else {                    // CHECK: File 0, [[@LINE]]:12 -> [[@LINE+2]]:6 = ((#1 - #2) - #3)
       int j = 2;
     }
   }
 }
 
                                // CHECK-NEXT: func3
 void func3(int x) {            // CHECK-NEXT: File 0, [[@LINE]]:19 -> {{[0-9]+}}:2 = #0
                                // CHECK-NEXT: File 0, [[@LINE+1]]:6 -> [[@LINE+1]]:11 = #0
-  if(x > 5) {                  // CHECK: File 0, [[@LINE]]:13 -> [[@LINE+6]]:4 = #1
+  if(x > 5) {                  // CHECK: File 0, [[@LINE]]:13 -> [[@LINE+7]]:4 = #1
     while(x >= 9) {            // CHECK-NEXT: File 0, [[@LINE]]:11 -> [[@LINE]]:17 = #1
-      return;                  // CHECK: File 0, [[@LINE-1]]:19 -> [[@LINE+2]]:6 = #2
+      return;                  // CHECK: File 0, [[@LINE-1]]:19 -> [[@LINE+3]]:6 = #2
+                               // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:14 -> [[@LINE+1]]:7 = 0
       --x;                     // CHECK-NEXT: File 0, [[@LINE]]:7 -> [[@LINE+1]]:6 = 0
-    }
+    }                          // CHECK-NEXT: Gap,File 0, [[@LINE]]:6 -> [[@LINE+1]]:5 = 0
     int i = 0;                 // CHECK-NEXT: File 0, [[@LINE]]:5 -> [[@LINE+1]]:4 = (#1 - #2)
-  }
+  }                            // CHECK-NEXT: Gap,File 0, [[@LINE]]:4 -> [[@LINE+1]]:3 = 0
   int j = 0;                   // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:2 = (#0 - #2)
 }
 
 int main(int argc, const char *argv[]) {
   func();
   func2();
   func3(10);
 }

clang/test/CoverageMapping/switch.cpp

 // RUN: %clang_cc1 -mllvm -emptyline-comment-coverage=false -fprofile-instrument=clang -fcoverage-mapping -dump-coverage-mapping -emit-llvm-only -std=c++1z -triple %itanium_abi_triple -main-file-name switch.cpp %s | FileCheck %s
 
 // CHECK: foo
-void foo(int i) {   // CHECK-NEXT: File 0, [[@LINE]]:17 -> [[@LINE+9]]:2 = #0
+void foo(int i) {   // CHECK-NEXT: File 0, [[@LINE]]:17 -> [[@LINE+11]]:2 = #0
   switch(i) {       // CHECK-NEXT: Branch,File 0, [[@LINE]]:10 -> [[@LINE]]:11 = ((#0 - #2) - #3), (#2 + #3)
-                    // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:13 -> [[@LINE+4]]:10 = 0
+                    // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:13 -> [[@LINE+5]]:10 = 0
   case 1:           // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:11 = #2
     return;         // CHECK-NEXT: Branch,File 0, [[@LINE-1]]:3 -> [[@LINE-1]]:9 = #2, (#0 - #2)
+                    // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:12 -> [[@LINE+1]]:3 = 0
   case 2:           // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:10 = #3
     break;          // CHECK-NEXT: Branch,File 0, [[@LINE-1]]:3 -> [[@LINE-1]]:9 = #3, (#0 - #3)
-  }                 // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:10 -> [[@LINE+1]]:3 = #1
+                    // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:10 -> [[@LINE+2]]:3 = #1
+  }                 // CHECK-NEXT: Gap,File 0, [[@LINE]]:4 -> [[@LINE+1]]:3 = 0
   int x = 0;        // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:2 = #1
 }
 
 int nop() { return 0; }
 
                     // CHECK: bar
 void bar(int i) {   // CHECK-NEXT: File 0, [[@LINE]]:17 -> [[@LINE+21]]:2 = #0
   switch (i)        // CHECK-NEXT: Branch,File 0, [[@LINE]]:11 -> [[@LINE]]:12 = #0, 0
int main() {        // CHECK-NEXT: File 0, [[@LINE]]:12 -> [[@LINE+38]]:2 = #0
   switch(i) {       // CHECK-NEXT: Gap,File 0, [[@LINE]]:13 -> [[@LINE+8]]:10 = 0
   case 0:           // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+2]]:10 = #2
     i = 1;          // CHECK-NEXT: Branch,File 0, [[@LINE-1]]:3 -> [[@LINE-1]]:9 = #2, (#0 - #2)
     break;
   case 1:           // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+2]]:10 = #3
     i = 2;          // CHECK-NEXT: Branch,File 0, [[@LINE-1]]:3 -> [[@LINE-1]]:9 = #3, (#0 - #3)
     break;
   default:          // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:10 = #4
     break;          // CHECK-NEXT: Branch,File 0, [[@LINE-1]]:3 -> [[@LINE-1]]:10 = #4, (#0 - #4)
   }                 // CHECK-NEXT: File 0, [[@LINE-1]]:10 -> [[@LINE+1]]:3 = #1
   switch(i) {       // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+26]]:2 = #1
   case 0:           // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:13 -> [[@LINE+6]]:10 = 0
     i = 1;          // CHECK-NEXT: File 0, [[@LINE-1]]:3 -> [[@LINE+1]]:10 = #6
     break;          // CHECK-NEXT: Branch,File 0, [[@LINE-2]]:3 -> [[@LINE-2]]:9 = #6, (#1 - #6)
   case 1:           // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+3]]:10 = #7
     i = 2;          // CHECK-NEXT: Branch,File 0, [[@LINE-1]]:3 -> [[@LINE-1]]:9 = #7, (#1 - #7)
   default:          // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:10 = (#7 + #8)

 }
 
                      // CHECK: pr44011
 int pr44011(int i) { // CHECK-NEXT: File 0, [[@LINE]]:20 -> {{.*}}:2 = #0
   switch (i) {       // CHECK-NEXT: Gap,File 0, [[@LINE]]:14 -> [[@LINE+6]]:13 = 0
 
   case 1:            // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:13 = #2
     return 0;        // CHECK-NEXT: Branch,File 0, [[@LINE-1]]:3 -> [[@LINE-1]]:9 = #2, (#0 - #2)
-
+                     // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:14 -> [[@LINE+1]]:3 = 0
   default:           // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:13 = #3
     return 1;        // CHECK-NEXT: Branch,File 0, [[@LINE-1]]:3 -> [[@LINE-1]]:10 = #3, (#0 - #3)
   }
 } // A region for counter #1 is missing due to the missing return.
 
 
 // FIXME: End location for "case 1" shouldn't point at the end of the switch.
                          // CHECK: fallthrough
int fallthrough(int i) { // CHECK-NEXT: File 0, [[@LINE]]:24 -> [[@LINE+14]]:2 = #0
   case 4:           // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+2]]:10 = (#4 + #5)
     i = 99;         // CHECK-NEXT: Branch,File 0, [[@LINE-1]]:3 -> [[@LINE-1]]:9 = #5, (#0 - #5)
     break;
   }
 }
 
 void abort(void) __attribute((noreturn));
                    // CHECK: noret
-int noret(int x) { // CHECK-NEXT: File 0, [[@LINE]]:18 -> [[@LINE+9]]:2
-  switch (x) {     // CHECK-NEXT: Gap,File 0, [[@LINE]]:14 -> [[@LINE+6]]:14 = 0
+int noret(int x) { // CHECK-NEXT: File 0, [[@LINE]]:18 -> [[@LINE+11]]:2
+  switch (x) {     // CHECK-NEXT: Gap,File 0, [[@LINE]]:14 -> [[@LINE+8]]:14 = 0
   default:         // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:12
     abort();      // CHECK-NEXT: Branch,File 0, [[@LINE-1]]:3 -> [[@LINE-1]]:10 = #2, (#0 - #2)
+                  // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:13 -> [[@LINE+1]]:3 = 0
   case 1:         // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:13
     return 5;     // CHECK-NEXT: Branch,File 0, [[@LINE-1]]:3 -> [[@LINE-1]]:9 = #3, (#0 - #3)
+                  // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:14 -> [[@LINE+1]]:3 = 0
   case 2:         // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:14
     return 10;    // CHECK-NEXT: Branch,File 0, [[@LINE-1]]:3 -> [[@LINE-1]]:9 = #4, (#0 - #4)
   }
 }

clang/test/CoverageMapping/switchmacro.c

 // RUN: %clang_cc1 -mllvm -emptyline-comment-coverage=false -fprofile-instrument=clang -fcoverage-mapping -dump-coverage-mapping -emit-llvm-only -main-file-name switchmacro.c %s | FileCheck %s
 
 #define FOO(x) (void)x
 
 // CHECK: foo
 int foo(int i) { // CHECK-NEXT: File 0, [[@LINE]]:16 -> {{[0-9]+}}:2 = #0
   switch (i) {   // CHECK-NEXT: Gap,File 0, [[@LINE]]:14 -> {{[0-9]+}}:11 = 0
   default:       // CHECK-NEXT: File 0, [[@LINE]]:3 -> {{[0-9]+}}:11 = #2
                  // CHECK-NEXT: Branch,File 0, [[@LINE-1]]:3 -> [[@LINE-1]]:10 = #2, (#0 - #2)
     if (i == 1)  // CHECK-NEXT: File 0, [[@LINE]]:9 -> [[@LINE]]:15 = #2
                  // CHECK-NEXT: Branch,File 0, [[@LINE-1]]:9 -> [[@LINE-1]]:15 = #3, (#2 - #3)
       return 0;  // CHECK: File 0, [[@LINE]]:7 -> [[@LINE]]:15 = #3
-                 // CHECK-NEXT: File 0, [[@LINE-1]]:15 -> [[@LINE+3]]:5 = (#2 - #3)
+                 // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:16 -> [[@LINE+3]]:5 = 0
     // CHECK-NEXT: Expansion,File 0, [[@LINE+2]]:5 -> [[@LINE+2]]:8 = (#2 - #3) (Expanded file = 1)
     // CHECK-NEXT: File 0, [[@LINE+1]]:8 -> {{[0-9]+}}:11 = (#2 - #3)
     FOO(1);
   case 0:        // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+2]]:13 = ((#2 + #4) - #3)
                  // CHECK-NEXT: Branch,File 0, [[@LINE-1]]:3 -> [[@LINE-1]]:9 = #4, (#0 - #4)
-    return 2;    // CHECK-NEXT: Gap,File 0, [[@LINE]]:13 -> [[@LINE+6]]:3 = #5
+    return 2;    // CHECK-NEXT: Gap,File 0, [[@LINE]]:14 -> [[@LINE+4]]:3 = 0
 
   // CHECK-NEXT: Expansion,File 0, [[@LINE+2]]:3 -> [[@LINE+2]]:6 = 0
   // CHECK-NEXT: File 0, [[@LINE+1]]:6 -> {{[0-9]+}}:11 = 0
   FOO(1);
   // CHECK-NEXT: File 0, [[@LINE+1]]:3 -> {{[0-9]+}}:11 = #5
   label: ;
   }
 }

clang/test/CoverageMapping/terminate-statements.cpp

+// RUN: %clang_cc1 -mllvm -emptyline-comment-coverage=false -fprofile-instrument=clang -fcoverage-mapping -dump-coverage-mapping -emit-llvm-only -main-file-name deferred-region.cpp -I %S/Inputs %s | FileCheck %s
+
+int f1() {
+  return 0;
+  return 0; // CHECK: Gap,File 0, [[@LINE-1]]:12 -> [[@LINE]]:3 = 0
+}
+
+int f2(int i) {
+  if (i)
+    return 0;
+  else
+    ;
+  return 1; // CHECK: Gap,File 0, [[@LINE-1]]:6 -> [[@LINE]]:3 = 0
+}
+
+int f3() {
+  for (int a = 1; a < 9; a--)
+    return a;
+  return 0; // CHECK: Gap,File 0, [[@LINE-1]]:14 -> [[@LINE]]:3 = 0
+}
+
+int f4(int i) {
+  while (i > 0) {
+    i++;
+    return i;
+  }
+  return 0; // CHECK: Gap,File 0, [[@LINE-1]]:4 -> [[@LINE]]:3 = 0
+}
+
+int f5(int i) {
+  do {
+    return i;
+  } while (i > 0);
+  return 0; // CHECK: Gap,File 0, [[@LINE-1]]:19 -> [[@LINE]]:3 = 0
+}
+
+int f6() {
+  int arr[] = {1, 2, 3, 4};
+  for (int i : arr) {
+    return i;
+  }
+  return 0; // CHECK: Gap,File 0, [[@LINE-1]]:4 -> [[@LINE]]:3 = 0
+}
+
+int f7() {
+  {
+    {
+      return 0;
+    }
+    return 0; // CHECK: Gap,File 0, [[@LINE-1]]:6 -> [[@LINE]]:5 = 0
+  }
+  return 0; // CHECK: Gap,File 0, [[@LINE-1]]:4 -> [[@LINE]]:3 = 0
+}
+
+int f8(int i) {
+  if (i == 1)
+    return 1;
+  if (i == 2) // CHECK: Gap,File 0, [[@LINE-1]]:14 -> [[@LINE]]:3 = 0
+    return 2;
+  if (i == 3) // CHECK: Gap,File 0, [[@LINE-1]]:14 -> [[@LINE]]:3 = 0
+    return 3;
+  return 4; // CHECK: Gap,File 0, [[@LINE-1]]:14 -> [[@LINE]]:3 = 0
+}
+
+int f9(int i) {
+  if (i == 1)
+    return 1;
+  else if (i == 2)
+    return 2;
+  return 3; // CHECK: Gap,File 0, [[@LINE-1]]:14 -> [[@LINE]]:3 = 0
+}
+
+int f10(int i) {
+  if (i == 1) {
+    return 0;
+    if (i == 2) // CHECK: Gap,File 0, [[@LINE-1]]:14 -> [[@LINE]]:5 = 0
+      return 0;
+  }
+  return 0; // CHECK: Gap,File 0, [[@LINE-1]]:4 -> [[@LINE]]:3 = 0
+}
+
+int f11(int i) {
+  if (i == 1)
+    i = 2;
+  else
+    return 0;
+  return 0; // CHECK: Gap,File 0, [[@LINE-1]]:14 -> [[@LINE]]:3 = 0
+}
+
+int f12(int i) {
+  int x = 1;
+  if (x == 1) {
+    if (x == 1) {
+      return 0;
+    }
+  } else if (x == 2) {
+    x = 2;
+  }
+  return 1; // CHECK: Gap,File 0, [[@LINE-1]]:4 -> [[@LINE]]:3 = 0
+}
+
+int f13(int i) {
+  if (i == 1) {
+    return 0;
+    if (i == 2) { // CHECK: Gap,File 0, [[@LINE-1]]:14 -> [[@LINE]]:5 = 0
+      i++;
+    }
+  }
+  return 0; // CHECK: Gap,File 0, [[@LINE-1]]:4 -> [[@LINE]]:3 = 0
+}
+
+int f14(int i) {
+  while (i == 0) {
+    while (i < 10) {
+      i++;
+      return 0;
+    }
+  }
+  return 0; // CHECK: Gap,File 0, [[@LINE-1]]:4 -> [[@LINE]]:3 = 0
+}
+
+int f15(int i) {
+  while (i == 0) {
+    return 0;
+    while (i < 10) { // CHECK: Gap,File 0, [[@LINE-1]]:14 -> [[@LINE]]:5 = 0
+      i++;
+    }
+  }
+  return 0; // CHECK: Gap,File 0, [[@LINE-1]]:4 -> [[@LINE]]:3 = 0
+}

clang/test/CoverageMapping/trycatch.cpp

 // RUN: %clang_cc1 -mllvm -emptyline-comment-coverage=false -triple %itanium_abi_triple -std=c++11 -fexceptions -fcxx-exceptions -fprofile-instrument=clang -fcoverage-mapping -dump-coverage-mapping -emit-llvm-only -main-file-name trycatch.cpp %s | FileCheck %s
 
 class Error {
 };
 
 class ImportantError {
 };
 
 class Warning {
 };
 
                                       // CHECK: func
 void func(int i) {                    // CHECK-NEXT: File 0, [[@LINE]]:18 -> {{[0-9]+}}:2 = #0
                                       // CHECK-NEXT: File 0, [[@LINE+1]]:6 -> [[@LINE+1]]:11 = #0
   if(i % 2) {                         // CHECK: File 0, [[@LINE]]:13 -> [[@LINE+4]]:4 = #1
-    throw Error();
+    throw Error();                    // CHECK-NEXT: Gap,File 0, [[@LINE]]:19 -> [[@LINE+1]]:5 = 0
     int j = 0;                        // CHECK-NEXT: File 0, [[@LINE]]:5 -> [[@LINE+2]]:4 = 0
                                       // CHECK: File 0, [[@LINE+1]]:10 -> [[@LINE+2]]:27 = (#0 - #1)
   } else if(i == 8)                   // CHECK-NEXT: File 0, [[@LINE]]:13 -> [[@LINE]]:19 = (#0 - #1)
     throw ImportantError();           // CHECK: File 0, [[@LINE]]:5 -> [[@LINE]]:27 = #2
 }
 
                                       // CHECK-NEXT: main
 int main() {                          // CHECK-NEXT: File 0, [[@LINE]]:12 -> [[@LINE+13]]:2 = #0

clang/test/CoverageMapping/unreachable-macro.c

 // RUN: %clang_cc1 -mllvm -emptyline-comment-coverage=false -fprofile-instrument=clang -fcoverage-mapping -dump-coverage-mapping -emit-llvm-only %s | FileCheck %s
 
 #define WHILE while (0) {}
 
 // CHECK: counters_in_macro_following_unreachable
 void counters_in_macro_following_unreachable() {
   // CHECK-NEXT: File 0, [[@LINE-1]]:48 -> {{[0-9]+}}:2 = #0
   return;
+  // CHECK-NEXT: Gap,File 0, [[@LINE-1]]:10 -> [[@LINE+3]]:3 = 0
   // CHECK-NEXT: Expansion,File 0, [[@LINE+2]]:3 -> [[@LINE+2]]:8 = 0
   // CHECK-NEXT: File 0, [[@LINE+1]]:8 -> [[@LINE+2]]:2 = 0
   WHILE
 }
 // CHECK-NEXT: File 1, 3:15 -> 3:27 = 0
 // CHECK-NEXT: File 1, 3:22 -> 3:23 = #1
 // CHECK-NEXT: Branch,File 1, 3:22 -> 3:23 = 0, 0
 // CHECK-NEXT: File 1, 3:25 -> 3:27 = #1

compiler-rt/test/profile/ContinuousSyncMode/runtime-counter-relocation.c

 // CHECK-COUNTS-NEXT: Instrumentation level: Front-end
 // CHECK-COUNTS-NEXT: Functions shown: 1
 // CHECK-COUNTS-NEXT: Total functions: 1
 // CHECK-COUNTS-NEXT: Maximum function count: 1
 // CHECK-COUNTS-NEXT: Maximum internal block count: 1
 
 // CHECK-COVERAGE: Filename                         Regions    Missed Regions     Cover   Functions  Missed Functions  Executed       Lines      Missed Lines     Cover
 // CHECK-COVERAGE-NEXT: ---
-// CHECK-COVERAGE-NEXT: runtime-counter-relocation.c      4                 1    75.00%           1                 0   100.00%           5                 2    60.00%
+// CHECK-COVERAGE-NEXT: runtime-counter-relocation.c      4                 1    75.00%           1                 0   100.00%           5                 1    80.00%
 // CHECK-COVERAGE-NEXT: ---
-// CHECK-COVERAGE-NEXT: TOTAL                             4                 1    75.00%           1                 0   100.00%           5                 2    60.00%
+// CHECK-COVERAGE-NEXT: TOTAL                             4                 1    75.00%           1                 0   100.00%           5                 1    80.00%
 
 extern int __llvm_profile_is_continuous_mode_enabled(void);
 
 int main() {
   if (__llvm_profile_is_continuous_mode_enabled())
     return 0;
   return 1;
 }