Index: lib/ProfileData/Coverage/CoverageMappingReader.cpp
===================================================================
--- lib/ProfileData/Coverage/CoverageMappingReader.cpp
+++ lib/ProfileData/Coverage/CoverageMappingReader.cpp
@@ -13,7 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ProfileData/Coverage/CoverageMappingReader.h"
-#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/DenseMap.h"
 #include "llvm/Object/MachOUniversal.h"
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/Support/Debug.h"
@@ -331,7 +331,9 @@
   typedef typename coverage::CovMapTraits<Version, IntPtrT>::NameRefType
       NameRefType;
 
-  llvm::DenseSet<NameRefType> UniqueFunctionMappingData;
+  // Maps function's name references to the indexes of their records
+  // in \c Records.
+  llvm::DenseMap<NameRefType, size_t> FunctionRecords;
   InstrProfSymtab &ProfileNames;
   std::vector<StringRef> &Filenames;
   std::vector<BinaryCoverageReader::ProfileMappingRecord> &Records;
@@ -396,8 +398,14 @@
       // Ignore this record if we already have a record that points to the same
       // function name. This is useful to ignore the redundant records for the
       // functions with ODR linkage.
+      // In addition, prefer records with non-zero hash values because they were
+      // emitted for real functions, whereas records with zero hashes are likely
+      // just placeholders for unused inline functions.
       NameRefType NameRef = CFR->template getFuncNameRef<Endian>();
-      if (!UniqueFunctionMappingData.insert(NameRef).second) {
+      auto InsertResult =
+          FunctionRecords.insert(std::make_pair(NameRef, Records.size()));
+      if (!InsertResult.second &&
+          (!FuncHash || Records[InsertResult.first->second].FunctionHash)) {
         CFR++;
         continue;
       }
@@ -406,9 +414,14 @@
       if (std::error_code EC =
               CFR->template getFuncName<Endian>(ProfileNames, FuncName))
         return EC;
-      Records.push_back(BinaryCoverageReader::ProfileMappingRecord(
+      BinaryCoverageReader::ProfileMappingRecord FunctionRecord(
           Version, FuncName, FuncHash, Mapping, FilenamesBegin,
-          Filenames.size() - FilenamesBegin));
+          Filenames.size() - FilenamesBegin);
+      if (InsertResult.second) {
+        Records.push_back(FunctionRecord);
+      } else {
+        Records[InsertResult.first->second] = FunctionRecord;
+      }
       CFR++;
     }
     return std::error_code();
Index: test/tools/llvm-cov/Inputs/prefer_used_to_unused.cpp
===================================================================
--- /dev/null
+++ test/tools/llvm-cov/Inputs/prefer_used_to_unused.cpp
@@ -0,0 +1,5 @@
+#include "prefer_used_to_unused.h"
+
+int main() {
+  return sample_func(5);
+}
Index: test/tools/llvm-cov/Inputs/prefer_used_to_unused.proftext
===================================================================
--- /dev/null
+++ test/tools/llvm-cov/Inputs/prefer_used_to_unused.proftext
@@ -0,0 +1,17 @@
+_Z11sample_funci
+# Func Hash:
+10
+# Num Counters:
+2
+# Counter Values:
+1
+1
+
+main
+# Func Hash:
+0
+# Num Counters:
+1
+# Counter Values:
+1
+
Index: test/tools/llvm-cov/prefer_used_to_unused.h
===================================================================
--- /dev/null
+++ test/tools/llvm-cov/prefer_used_to_unused.h
@@ -0,0 +1,16 @@
+// Check that llvm-cov loads coverage mapping data for real function even though
+// an unused function comes first.
+
+// If you need to rebuild the 'covmapping' file for this test, please use
+// the following commands:
+// clang++ -fprofile-instr-generate -fcoverage-mapping -o tmp -x c++ prefer_used_to_unused.h prefer_used_to_unused.cpp
+// llvm-cov convert-for-testing -o prefer_used_to_unused.covmapping tmp
+
+// RUN: llvm-profdata merge %S/Inputs/prefer_used_to_unused.proftext -o %t.profdata
+// RUN: llvm-cov show %S/Inputs/prefer_used_to_unused.covmapping -instr-profile %t.profdata -filename-equivalence %s | FileCheck %s
+
+inline int sample_func(int A) { // CHECK:      1| [[@LINE]]|inline int sample_func(int A) {
+  if (A > 0)                    // CHECK-NEXT: 1| [[@LINE]]|  if (A > 0)
+    return A;                   // CHECK-NEXT: 1| [[@LINE]]|    return A;
+  return 0;                     // CHECK-NEXT: 0| [[@LINE]]|  return 0;
+}                               // CHECK-NEXT: 1| [[@LINE]]|}