diff --git a/cmds/statsd/src/config/ConfigManager.cpp b/cmds/statsd/src/config/ConfigManager.cpp
index 16b7e79..5fea90b 100644
--- a/cmds/statsd/src/config/ConfigManager.cpp
+++ b/cmds/statsd/src/config/ConfigManager.cpp
@@ -106,14 +106,14 @@
         // Add to set.
         mConfigs[key.GetUid()].insert(key);
 
-        for (sp<ConfigListener> listener : mListeners) {
+        for (const sp<ConfigListener>& listener : mListeners) {
             broadcastList.push_back(listener);
         }
     }
 
     const int64_t timestampNs = getElapsedRealtimeNs();
     // Tell everyone
-    for (sp<ConfigListener> listener : broadcastList) {
+    for (const sp<ConfigListener>& listener : broadcastList) {
         listener->OnConfigUpdated(timestampNs, key, config);
     }
 }
@@ -137,7 +137,7 @@
         if (uidIt != mConfigs.end() && uidIt->second.find(key) != uidIt->second.end()) {
             // Remove from map
             uidIt->second.erase(key);
-            for (sp<ConfigListener> listener : mListeners) {
+            for (const sp<ConfigListener>& listener : mListeners) {
                 broadcastList.push_back(listener);
             }
         }
@@ -153,7 +153,7 @@
         remove_saved_configs(key);
     }
 
-    for (sp<ConfigListener> listener:broadcastList) {
+    for (const sp<ConfigListener>& listener:broadcastList) {
         listener->OnConfigRemoved(key);
     }
 }
@@ -183,7 +183,7 @@
 
         mConfigs.erase(uidIt);
 
-        for (sp<ConfigListener> listener : mListeners) {
+        for (const sp<ConfigListener>& listener : mListeners) {
             broadcastList.push_back(listener);
         }
     }
@@ -191,7 +191,7 @@
     // Remove separately so if they do anything in the callback they can't mess up our iteration.
     for (auto& key : removed) {
         // Tell everyone
-        for (sp<ConfigListener> listener:broadcastList) {
+        for (const sp<ConfigListener>& listener:broadcastList) {
             listener->OnConfigRemoved(key);
         }
     }
@@ -213,7 +213,7 @@
         }
 
         mConfigReceivers.clear();
-        for (sp<ConfigListener> listener : mListeners) {
+        for (const sp<ConfigListener>& listener : mListeners) {
             broadcastList.push_back(listener);
         }
     }
@@ -221,7 +221,7 @@
     // Remove separately so if they do anything in the callback they can't mess up our iteration.
     for (auto& key : removed) {
         // Tell everyone
-        for (sp<ConfigListener> listener:broadcastList) {
+        for (const sp<ConfigListener>& listener:broadcastList) {
             listener->OnConfigRemoved(key);
         }
     }
diff --git a/cmds/statsd/src/external/SubsystemSleepStatePuller.cpp b/cmds/statsd/src/external/SubsystemSleepStatePuller.cpp
index 4501b64..2713d327 100644
--- a/cmds/statsd/src/external/SubsystemSleepStatePuller.cpp
+++ b/cmds/statsd/src/external/SubsystemSleepStatePuller.cpp
@@ -111,7 +111,7 @@
                              (long long)state.residencyInMsecSinceBoot,
                              (long long)state.totalTransitions,
                              state.supportedOnlyInSuspend ? 1 : 0);
-                        for (auto voter : state.voters) {
+                        for (const auto& voter : state.voters) {
                             auto voterPtr = make_shared<LogEvent>(
                                 android::util::SUBSYSTEM_SLEEP_STATE,
                                 wallClockTimestampNs, elapsedTimestampNs);
diff --git a/cmds/statsd/src/metrics/MetricsManager.cpp b/cmds/statsd/src/metrics/MetricsManager.cpp
index 4fac0e1..a6c7f3a 100644
--- a/cmds/statsd/src/metrics/MetricsManager.cpp
+++ b/cmds/statsd/src/metrics/MetricsManager.cpp
@@ -395,7 +395,7 @@
 // Returns the total byte size of all metrics managed by a single config source.
 size_t MetricsManager::byteSize() {
     size_t totalSize = 0;
-    for (auto metricProducer : mAllMetricProducers) {
+    for (const auto& metricProducer : mAllMetricProducers) {
         totalSize += metricProducer->byteSize();
     }
     return totalSize;
diff --git a/cmds/statsd/src/metrics/metrics_manager_util.cpp b/cmds/statsd/src/metrics/metrics_manager_util.cpp
index 811a00e..a1c80b8 100644
--- a/cmds/statsd/src/metrics/metrics_manager_util.cpp
+++ b/cmds/statsd/src/metrics/metrics_manager_util.cpp
@@ -537,7 +537,7 @@
         }
         noReportMetricIds.insert(no_report_metric);
     }
-    for (auto it : allMetricProducers) {
+    for (const auto& it : allMetricProducers) {
         uidMap.addListener(it);
     }
     return true;
diff --git a/cmds/statsd/src/packages/UidMap.cpp b/cmds/statsd/src/packages/UidMap.cpp
index 73ac968..88957df 100644
--- a/cmds/statsd/src/packages/UidMap.cpp
+++ b/cmds/statsd/src/packages/UidMap.cpp
@@ -141,7 +141,7 @@
     // listener removes itself before we call it. It's then the listener's job to handle it (expect
     // the callback to be called after listener is removed, and the listener should properly
     // ignore it).
-    for (auto weakPtr : broadcastList) {
+    for (const auto& weakPtr : broadcastList) {
         auto strongPtr = weakPtr.promote();
         if (strongPtr != NULL) {
             strongPtr->onUidMapReceived(timestamp);
@@ -181,7 +181,7 @@
         StatsdStats::getInstance().setUidMapChanges(mChanges.size());
     }
 
-    for (auto weakPtr : broadcastList) {
+    for (const auto& weakPtr : broadcastList) {
         auto strongPtr = weakPtr.promote();
         if (strongPtr != NULL) {
             strongPtr->notifyAppUpgrade(timestamp, appName, uid, versionCode);
@@ -248,7 +248,7 @@
         getListenerListCopyLocked(&broadcastList);
     }
 
-    for (auto weakPtr : broadcastList) {
+    for (const auto& weakPtr : broadcastList) {
         auto strongPtr = weakPtr.promote();
         if (strongPtr != NULL) {
             strongPtr->notifyAppRemoved(timestamp, app, uid);
diff --git a/cmds/statsd/tests/anomaly/AnomalyTracker_test.cpp b/cmds/statsd/tests/anomaly/AnomalyTracker_test.cpp
index 218d52a..e125887 100644
--- a/cmds/statsd/tests/anomaly/AnomalyTracker_test.cpp
+++ b/cmds/statsd/tests/anomaly/AnomalyTracker_test.cpp
@@ -71,12 +71,12 @@
                          const std::shared_ptr<DimToValMap>& currentBucket,
                          const std::set<const MetricDimensionKey>& trueList,
                          const std::set<const MetricDimensionKey>& falseList) {
-    for (MetricDimensionKey key : trueList) {
+    for (const MetricDimensionKey& key : trueList) {
         if (!tracker.detectAnomaly(bucketNum, key, getBucketValue(currentBucket, key))) {
             return false;
         }
     }
-    for (MetricDimensionKey key : falseList) {
+    for (const MetricDimensionKey& key : falseList) {
         if (tracker.detectAnomaly(bucketNum, key, getBucketValue(currentBucket, key))) {
             return false;
         }
diff --git a/core/jni/com_android_internal_os_Zygote.cpp b/core/jni/com_android_internal_os_Zygote.cpp
index 01105ba..2e6b1b9 100644
--- a/core/jni/com_android_internal_os_Zygote.cpp
+++ b/core/jni/com_android_internal_os_Zygote.cpp
@@ -414,7 +414,7 @@
     }
     endmntent(fp);
 
-    for (auto path : toUnmount) {
+    for (const auto& path : toUnmount) {
         if (umount2(path.c_str(), MNT_DETACH)) {
             ALOGW("Failed to unmount %s: %s", path.c_str(), strerror(errno));
         }
diff --git a/libs/hwui/tests/common/scenes/ShapeAnimation.cpp b/libs/hwui/tests/common/scenes/ShapeAnimation.cpp
index 0d87776..d189a93 100644
--- a/libs/hwui/tests/common/scenes/ShapeAnimation.cpp
+++ b/libs/hwui/tests/common/scenes/ShapeAnimation.cpp
@@ -76,7 +76,7 @@
                             paint.setStrokeWidth(strokeWidth);
                             // fill column with each op
                             int middleCount = canvas.save(SaveFlags::MatrixClip);
-                            for (auto op : ops) {
+                            for (const auto& op : ops) {
                                 int innerCount = canvas.save(SaveFlags::MatrixClip);
                                 canvas.clipRect(0, 0, cellSize, cellSize, SkClipOp::kIntersect);
                                 canvas.drawColor(Color::White, SkBlendMode::kSrcOver);
diff --git a/libs/hwui/tests/unit/VectorDrawableTests.cpp b/libs/hwui/tests/unit/VectorDrawableTests.cpp
index 02f740c..4f299e3 100644
--- a/libs/hwui/tests/unit/VectorDrawableTests.cpp
+++ b/libs/hwui/tests/unit/VectorDrawableTests.cpp
@@ -251,7 +251,7 @@
 }
 
 TEST(PathParser, parseStringForData) {
-    for (TestData testData : sTestDataSet) {
+    for (const TestData& testData : sTestDataSet) {
         PathParser::ParseResult result;
         // Test generated path data against the given data.
         PathData pathData;
@@ -271,7 +271,7 @@
 }
 
 TEST(VectorDrawableUtils, createSkPathFromPathData) {
-    for (TestData testData : sTestDataSet) {
+    for (const TestData& testData : sTestDataSet) {
         SkPath expectedPath;
         testData.skPathLamda(&expectedPath);
         SkPath actualPath;
@@ -281,7 +281,7 @@
 }
 
 TEST(PathParser, parseAsciiStringForSkPath) {
-    for (TestData testData : sTestDataSet) {
+    for (const TestData& testData : sTestDataSet) {
         PathParser::ParseResult result;
         size_t length = strlen(testData.pathString);
         // Check the return value as well as the SkPath generated.
@@ -304,8 +304,8 @@
 }
 
 TEST(VectorDrawableUtils, morphPathData) {
-    for (TestData fromData : sTestDataSet) {
-        for (TestData toData : sTestDataSet) {
+    for (const TestData& fromData : sTestDataSet) {
+        for (const TestData& toData : sTestDataSet) {
             bool canMorph = VectorDrawableUtils::canMorph(fromData.pathData, toData.pathData);
             if (fromData.pathData == toData.pathData) {
                 EXPECT_TRUE(canMorph);
@@ -319,8 +319,8 @@
 
 TEST(VectorDrawableUtils, interpolatePathData) {
     // Interpolate path data with itself and every other path data
-    for (TestData fromData : sTestDataSet) {
-        for (TestData toData : sTestDataSet) {
+    for (const TestData& fromData : sTestDataSet) {
+        for (const TestData& toData : sTestDataSet) {
             PathData outData;
             bool success = VectorDrawableUtils::interpolatePathData(&outData, fromData.pathData,
                                                                     toData.pathData, 0.5);
@@ -331,7 +331,7 @@
 
     float fractions[] = {0, 0.00001, 0.28, 0.5, 0.7777, 0.9999999, 1};
     // Now try to interpolate with a slightly modified version of self and expect success
-    for (TestData fromData : sTestDataSet) {
+    for (const TestData& fromData : sTestDataSet) {
         PathData toPathData = fromData.pathData;
         for (size_t i = 0; i < toPathData.points.size(); i++) {
             toPathData.points[i]++;
diff --git a/tools/aapt2/ResourceParser.cpp b/tools/aapt2/ResourceParser.cpp
index 39ca80b..968376b 100644
--- a/tools/aapt2/ResourceParser.cpp
+++ b/tools/aapt2/ResourceParser.cpp
@@ -78,7 +78,7 @@
 
 static uint32_t ParseFormatAttribute(const StringPiece& str) {
   uint32_t mask = 0;
-  for (StringPiece part : util::Tokenize(str, '|')) {
+  for (const StringPiece& part : util::Tokenize(str, '|')) {
     StringPiece trimmed_part = util::TrimWhitespace(part);
     uint32_t type = ParseFormatType(trimmed_part);
     if (type == 0) {
diff --git a/tools/aapt2/ResourceUtils.cpp b/tools/aapt2/ResourceUtils.cpp
index 82d9e04..99420de 100644
--- a/tools/aapt2/ResourceUtils.cpp
+++ b/tools/aapt2/ResourceUtils.cpp
@@ -360,7 +360,7 @@
     return util::make_unique<BinaryPrimitive>(flags);
   }
 
-  for (StringPiece part : util::Tokenize(str, '|')) {
+  for (const StringPiece& part : util::Tokenize(str, '|')) {
     StringPiece trimmed_part = util::TrimWhitespace(part);
 
     bool flag_set = false;
diff --git a/tools/aapt2/cmd/Compile.cpp b/tools/aapt2/cmd/Compile.cpp
index 411ad74..0b43c5d 100644
--- a/tools/aapt2/cmd/Compile.cpp
+++ b/tools/aapt2/cmd/Compile.cpp
@@ -486,7 +486,7 @@
     }
 
     Printer r_txt_printer(&fout_text);
-    for (const auto res : xmlres->file.exported_symbols) {
+    for (const auto& res : xmlres->file.exported_symbols) {
       r_txt_printer.Print("default int id ");
       r_txt_printer.Println(res.name.entry);
     }
diff --git a/tools/aapt2/java/AnnotationProcessor.cpp b/tools/aapt2/java/AnnotationProcessor.cpp
index 8d91b00..a4610b2 100644
--- a/tools/aapt2/java/AnnotationProcessor.cpp
+++ b/tools/aapt2/java/AnnotationProcessor.cpp
@@ -113,7 +113,7 @@
 void AnnotationProcessor::Print(Printer* printer) const {
   if (has_comments_) {
     std::string result = comment_.str();
-    for (StringPiece line : util::Tokenize(result, '\n')) {
+    for (const StringPiece& line : util::Tokenize(result, '\n')) {
       printer->Println(line);
     }
     printer->Println(" */");
diff --git a/tools/aapt2/util/Files.cpp b/tools/aapt2/util/Files.cpp
index 5a8ff09..a407c22 100644
--- a/tools/aapt2/util/Files.cpp
+++ b/tools/aapt2/util/Files.cpp
@@ -165,7 +165,7 @@
 
 std::string PackageToPath(const StringPiece& package) {
   std::string out_path;
-  for (StringPiece part : util::Tokenize(package, '.')) {
+  for (const StringPiece& part : util::Tokenize(package, '.')) {
     AppendPath(&out_path, part);
   }
   return out_path;