4 files changed, 70 insertions, 11 deletions

diff --git a/clang/lib/CodeGen/CoverageMappingGen.cpp b/clang/lib/CodeGen/CoverageMappingGen.cpp
index bd34e1c5a85..44c90e30cd8 100644
--- a/clang/lib/CodeGen/CoverageMappingGen.cpp
+++ b/clang/lib/CodeGen/CoverageMappingGen.cpp
@@ -130,6 +130,16 @@ public:
     return strcmp(SM.getBufferName(SM.getSpellingLoc(Loc)), "<built-in>") == 0;
   }
 
+  /// \brief Check whether \c Loc is included or expanded from \c Parent.
+  bool isNestedIn(SourceLocation Loc, FileID Parent) {
+    do {
+      Loc = getIncludeOrExpansionLoc(Loc);
+      if (Loc.isInvalid())
+        return false;
+    } while (!SM.isInFileID(Loc, Parent));
+    return true;
+  }
+
   /// \brief Get the start of \c S ignoring macro arguments and builtin macros.
   SourceLocation getStart(const Stmt *S) {
     SourceLocation Loc = S->getLocStart();
@@ -310,7 +320,27 @@ struct EmptyCoverageMappingBuilder : public CoverageMappingBuilder {
     if (!D->hasBody())
       return;
     auto Body = D->getBody();
-    SourceRegions.emplace_back(Counter(), getStart(Body), getEnd(Body));
+    SourceLocation Start = getStart(Body);
+    SourceLocation End = getEnd(Body);
+    if (!SM.isWrittenInSameFile(Start, End)) {
+      // Walk up to find the common ancestor.
+      // Correct the locations accordingly.
+      FileID StartFileID = SM.getFileID(Start);
+      FileID EndFileID = SM.getFileID(End);
+      while (StartFileID != EndFileID && !isNestedIn(End, StartFileID)) {
+        Start = getIncludeOrExpansionLoc(Start);
+        assert(Start.isValid() &&
+               "Declaration start location not nested within a known region");
+        StartFileID = SM.getFileID(Start);
+      }
+      while (StartFileID != EndFileID) {
+        End = getPreciseTokenLocEnd(getIncludeOrExpansionLoc(End));
+        assert(End.isValid() &&
+               "Declaration end location not nested within a known region");
+        EndFileID = SM.getFileID(End);
+      }
+    }
+    SourceRegions.emplace_back(Counter(), Start, End);
   }
 
   /// \brief Write the mapping data to the output stream
@@ -471,16 +501,6 @@ struct CounterCoverageMappingBuilder
       MostRecentLocation = getIncludeOrExpansionLoc(MostRecentLocation);
   }
 
-  /// \brief Check whether \c Loc is included or expanded from \c Parent.
-  bool isNestedIn(SourceLocation Loc, FileID Parent) {
-    do {
-      Loc = getIncludeOrExpansionLoc(Loc);
-      if (Loc.isInvalid())
-        return false;
-    } while (!SM.isInFileID(Loc, Parent));
-    return true;
-  }
-
   /// \brief Adjust regions and state when \c NewLoc exits a file.
   ///
   /// If moving from our most recently tracked location to \c NewLoc exits any
diff --git a/clang/test/CoverageMapping/Inputs/ends_a_scope_only b/clang/test/CoverageMapping/Inputs/ends_a_scope_only
new file mode 100644
index 00000000000..5c34318c214
--- /dev/null
+++ b/clang/test/CoverageMapping/Inputs/ends_a_scope_only
@@ -0,0 +1 @@
+}
diff --git a/clang/test/CoverageMapping/Inputs/starts_a_scope_only b/clang/test/CoverageMapping/Inputs/starts_a_scope_only
new file mode 100644
index 00000000000..98232c64fce
--- /dev/null
+++ b/clang/test/CoverageMapping/Inputs/starts_a_scope_only
@@ -0,0 +1 @@
+{
diff --git a/clang/test/CoverageMapping/unused_function.cpp b/clang/test/CoverageMapping/unused_function.cpp
new file mode 100644
index 00000000000..b50b0893790
--- /dev/null
+++ b/clang/test/CoverageMapping/unused_function.cpp
@@ -0,0 +1,37 @@
+// RUN: %clang_cc1 -fprofile-instrument=clang -fcoverage-mapping -dump-coverage-mapping -emit-llvm-only %s | FileCheck %s
+
+#define START_SCOPE {
+#define END_SCOPE }
+
+// CHECK: _Z2f0v:
+// CHECK-NEXT: File 0, [[@LINE+1]]:18 -> [[@LINE+1]]:20 = 0
+inline void f0() {}
+
+// CHECK: _Z2f1v:
+// CHECK-NEXT: File 0, [[@LINE+1]]:18 -> [[@LINE+1]]:31 = 0
+inline void f1() START_SCOPE }
+
+// CHECK: _Z2f2v:
+// CHECK-NEXT: File 0, [[@LINE+1]]:18 -> [[@LINE+1]]:29 = 0
+inline void f2() { END_SCOPE
+
+// CHECK: _Z2f3v:
+// CHECK-NEXT: File 0, [[@LINE+1]]:18 -> [[@LINE+1]]:39 = 0
+inline void f3() START_SCOPE END_SCOPE
+
+// CHECK: _Z2f4v:
+// CHECK-NEXT: File 0, [[@LINE+2]]:10 -> [[@LINE+3]]:2 = 0
+inline void f4()
+#include "Inputs/starts_a_scope_only"
+}
+
+// CHECK: _Z2f5v:
+// CHECK-NEXT: File 0, [[@LINE+1]]:18 -> [[@LINE+2]]:36 = 0
+inline void f5() {
+#include "Inputs/ends_a_scope_only"
+
+// CHECK: _Z2f6v:
+// CHECK-NEXT: File 0, [[@LINE+2]]:10 -> [[@LINE+3]]:36 = 0
+inline void f6()
+#include "Inputs/starts_a_scope_only"
+#include "Inputs/ends_a_scope_only"