1 files changed, 23 insertions, 5 deletions

diff --git a/clang/lib/CodeGen/CoverageMappingGen.cpp b/clang/lib/CodeGen/CoverageMappingGen.cpp
index 080525c8e6c..e008f44fc6f 100644
--- a/clang/lib/CodeGen/CoverageMappingGen.cpp
+++ b/clang/lib/CodeGen/CoverageMappingGen.cpp
@@ -92,6 +92,14 @@ public:
   /// \brief The source mapping regions for this function.
   std::vector<SourceMappingRegion> SourceRegions;
 
+  /// \brief A set of regions which can be used as a filter.
+  ///
+  /// It is produced by emitExpansionRegions() and is used in
+  /// emitSourceRegions() to suppress producing code regions if
+  /// the same area is covered by expansion regions.
+  typedef llvm::SmallSet<std::pair<SourceLocation, SourceLocation>, 8>
+      SourceRegionFilter;
+
   CoverageMappingBuilder(CoverageMappingModuleGen &CVM, SourceManager &SM,
                          const LangOptions &LangOpts)
       : CVM(CVM), SM(SM), LangOpts(LangOpts) {}
@@ -249,7 +257,7 @@ public:
 
   /// \brief Generate the coverage counter mapping regions from collected
   /// source regions.
-  void emitSourceRegions() {
+  void emitSourceRegions(const SourceRegionFilter &Filter) {
     for (const auto &Region : SourceRegions) {
       assert(Region.hasEndLoc() && "incomplete region");
 
@@ -269,6 +277,13 @@ public:
       assert(SM.isWrittenInSameFile(LocStart, LocEnd) &&
              "region spans multiple files");
 
+      // Don't add code regions for the area covered by expansion regions.
+      // This not only suppresses redundant regions, but sometimes prevents
+      // creating regions with wrong counters if, for example, a statement's
+      // body ends at the end of a nested macro.
+      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);
@@ -283,7 +298,8 @@ public:
   }
 
   /// \brief Generate expansion regions for each virtual file we've seen.
-  void emitExpansionRegions() {
+  SourceRegionFilter emitExpansionRegions() {
+    SourceRegionFilter Filter;
     for (const auto &FM : FileIDMapping) {
       SourceLocation ExpandedLoc = FM.second.second;
       SourceLocation ParentLoc = getIncludeOrExpansionLoc(ExpandedLoc);
@@ -299,6 +315,7 @@ public:
       SourceLocation LocEnd = getPreciseTokenLocEnd(ParentLoc);
       assert(SM.isWrittenInSameFile(ParentLoc, LocEnd) &&
              "region spans multiple files");
+      Filter.insert(std::make_pair(ParentLoc, LocEnd));
 
       unsigned LineStart = SM.getSpellingLineNumber(ParentLoc);
       unsigned ColumnStart = SM.getSpellingColumnNumber(ParentLoc);
@@ -309,6 +326,7 @@ public:
           *ParentFileID, *ExpandedFileID, LineStart, ColumnStart, LineEnd,
           ColumnEnd));
     }
+    return Filter;
   }
 };
 
@@ -350,7 +368,7 @@ struct EmptyCoverageMappingBuilder : public CoverageMappingBuilder {
   void write(llvm::raw_ostream &OS) {
     SmallVector<unsigned, 16> FileIDMapping;
     gatherFileIDs(FileIDMapping);
-    emitSourceRegions();
+    emitSourceRegions(SourceRegionFilter());
 
     if (MappingRegions.empty())
       return;
@@ -605,8 +623,8 @@ struct CounterCoverageMappingBuilder
   void write(llvm::raw_ostream &OS) {
     llvm::SmallVector<unsigned, 8> VirtualFileMapping;
     gatherFileIDs(VirtualFileMapping);
-    emitSourceRegions();
-    emitExpansionRegions();
+    SourceRegionFilter Filter = emitExpansionRegions();
+    emitSourceRegions(Filter);
     gatherSkippedRegions();
 
     if (MappingRegions.empty())