diff --git a/cmds/statsd/Android.mk b/cmds/statsd/Android.mk
index 67b9089..740fdc0 100644
--- a/cmds/statsd/Android.mk
+++ b/cmds/statsd/Android.mk
@@ -116,10 +116,8 @@
 
 LOCAL_CFLAGS += \
     -Wall \
+    -Wextra \
     -Werror \
-    -Wno-missing-field-initializers \
-    -Wno-unused-variable \
-    -Wno-unused-function \
     -Wno-unused-parameter
 
 ifeq (debug,)
diff --git a/cmds/statsd/src/FieldValue.cpp b/cmds/statsd/src/FieldValue.cpp
index 7b0b69a..6894bcf 100644
--- a/cmds/statsd/src/FieldValue.cpp
+++ b/cmds/statsd/src/FieldValue.cpp
@@ -23,6 +23,23 @@
 namespace os {
 namespace statsd {
 
+int32_t getEncodedField(int32_t pos[], int32_t depth, bool includeDepth) {
+    int32_t field = 0;
+    for (int32_t i = 0; i <= depth; i++) {
+        int32_t shiftBits = 8 * (kMaxLogDepth - i);
+        field |= (pos[i] << shiftBits);
+    }
+
+    if (includeDepth) {
+        field |= (depth << 24);
+    }
+    return field;
+}
+
+int32_t encodeMatcherMask(int32_t mask[], int32_t depth) {
+    return getEncodedField(mask, depth, false) | 0xff000000;
+}
+
 bool Field::matches(const Matcher& matcher) const {
     if (mTag != matcher.mMatcher.getTag()) {
         return false;
@@ -32,7 +49,7 @@
     }
 
     return false;
-};
+}
 
 void translateFieldMatcher(int tag, const FieldMatcher& matcher, int depth, int* pos, int* mask,
                            std::vector<Matcher>* output) {
@@ -71,7 +88,6 @@
 
     if (matcher.child_size() == 0) {
         output->push_back(Matcher(Field(tag, pos, depth), encodeMatcherMask(mask, depth)));
-        Matcher matcher = Matcher(Field(tag, pos, depth), encodeMatcherMask(mask, depth));
     } else {
         for (const auto& child : matcher.child()) {
             translateFieldMatcher(tag, child, depth + 1, pos, mask, output);
diff --git a/cmds/statsd/src/FieldValue.h b/cmds/statsd/src/FieldValue.h
index 7484108..d17dded 100644
--- a/cmds/statsd/src/FieldValue.h
+++ b/cmds/statsd/src/FieldValue.h
@@ -33,29 +33,14 @@
 
 enum Type { INT, LONG, FLOAT, STRING };
 
+int32_t getEncodedField(int32_t pos[], int32_t depth, bool includeDepth);
 
-static int32_t getEncodedField(int32_t pos[], int32_t depth, bool includeDepth) {
-    int32_t field = 0;
-    for (int32_t i = 0; i <= depth; i++) {
-        int32_t shiftBits = 8 * (kMaxLogDepth - i);
-        field |= (pos[i] << shiftBits);
-    }
-
-    if (includeDepth) {
-        field |= (depth << 24);
-    }
-    return field;
-}
-
-static int32_t encodeMatcherMask(int32_t mask[], int32_t depth) {
-    return getEncodedField(mask, depth, false) | 0xff000000;
-}
+int32_t encodeMatcherMask(int32_t mask[], int32_t depth);
 
 // Get the encoded field for a leaf with a [field] number at depth 0;
-static int32_t getSimpleField(size_t field) {
+inline int32_t getSimpleField(size_t field) {
     return ((int32_t)field << 8 * 2);
 }
-
 /**
  * Field is a wrapper class for 2 integers that represents the field of a log element in its Atom
  * proto.
diff --git a/cmds/statsd/src/HashableDimensionKey.cpp b/cmds/statsd/src/HashableDimensionKey.cpp
index 68e2176..d901bd6 100644
--- a/cmds/statsd/src/HashableDimensionKey.cpp
+++ b/cmds/statsd/src/HashableDimensionKey.cpp
@@ -68,7 +68,6 @@
         for (const auto& value : values) {
             // TODO: potential optimization here to break early because all fields are naturally
             // sorted.
-            int32_t filteredField;
             if (value.mField.matches(matcher)) {
                 matchedResults.push_back(FieldValue(
                         Field(value.mField.getTag(), (value.mField.getField() & matcher.mMask)),
@@ -148,7 +147,6 @@
                        const std::vector<FieldValue>& values, std::vector<FieldValue>* output) {
     for (const auto& field : matcherFields) {
         for (const auto& value : values) {
-            int filteredField;
             if (value.mField.matches(field)) {
                 output->push_back(value);
             }
diff --git a/cmds/statsd/src/StatsLogProcessor.cpp b/cmds/statsd/src/StatsLogProcessor.cpp
index 3a20b12..05350db 100644
--- a/cmds/statsd/src/StatsLogProcessor.cpp
+++ b/cmds/statsd/src/StatsLogProcessor.cpp
@@ -57,7 +57,7 @@
 const int FIELD_ID_UID = 1;
 const int FIELD_ID_ID = 2;
 // for ConfigMetricsReport
-const int FIELD_ID_METRICS = 1;
+// const int FIELD_ID_METRICS = 1; // written in MetricsManager.cpp
 const int FIELD_ID_UID_MAP = 2;
 const int FIELD_ID_LAST_REPORT_NANOS = 3;
 const int FIELD_ID_CURRENT_REPORT_NANOS = 4;
diff --git a/cmds/statsd/src/StatsService.cpp b/cmds/statsd/src/StatsService.cpp
index ee38667..b92e897 100644
--- a/cmds/statsd/src/StatsService.cpp
+++ b/cmds/statsd/src/StatsService.cpp
@@ -121,8 +121,6 @@
  */
 status_t StatsService::onTransact(uint32_t code, const Parcel& data, Parcel* reply,
                                   uint32_t flags) {
-    status_t err;
-
     switch (code) {
         case SHELL_COMMAND_TRANSACTION: {
             int in = data.readFileDescriptor();
diff --git a/cmds/statsd/src/guardrail/StatsdStats.cpp b/cmds/statsd/src/guardrail/StatsdStats.cpp
index 06c5b00..a38f98f 100644
--- a/cmds/statsd/src/guardrail/StatsdStats.cpp
+++ b/cmds/statsd/src/guardrail/StatsdStats.cpp
@@ -45,18 +45,9 @@
 const int FIELD_ID_ATOM_STATS = 7;
 const int FIELD_ID_UIDMAP_STATS = 8;
 const int FIELD_ID_ANOMALY_ALARM_STATS = 9;
-const int FIELD_ID_PULLED_ATOM_STATS = 10;
+// const int FIELD_ID_PULLED_ATOM_STATS = 10; // The proto is written in stats_log_util.cpp
 const int FIELD_ID_LOGGER_ERROR_STATS = 11;
 
-const int FIELD_ID_MATCHER_STATS_NAME = 1;
-const int FIELD_ID_MATCHER_STATS_COUNT = 2;
-
-const int FIELD_ID_CONDITION_STATS_NAME = 1;
-const int FIELD_ID_CONDITION_STATS_COUNT = 2;
-
-const int FIELD_ID_METRIC_STATS_NAME = 1;
-const int FIELD_ID_METRIC_STATS_COUNT = 2;
-
 const int FIELD_ID_ATOM_STATS_TAG = 1;
 const int FIELD_ID_ATOM_STATS_COUNT = 2;
 
diff --git a/cmds/statsd/src/logd/LogEvent.cpp b/cmds/statsd/src/logd/LogEvent.cpp
index ce3a4b9..1e1fb35 100644
--- a/cmds/statsd/src/logd/LogEvent.cpp
+++ b/cmds/statsd/src/logd/LogEvent.cpp
@@ -166,10 +166,6 @@
 void LogEvent::init(android_log_context context) {
     android_log_list_element elem;
     int i = 0;
-
-    int seenListStart = 0;
-
-    int32_t field = 0;
     int depth = -1;
     int pos[] = {1, 1, 1};
     do {
diff --git a/cmds/statsd/src/metrics/DurationMetricProducer.cpp b/cmds/statsd/src/metrics/DurationMetricProducer.cpp
index 6b321e1..b6ec375 100644
--- a/cmds/statsd/src/metrics/DurationMetricProducer.cpp
+++ b/cmds/statsd/src/metrics/DurationMetricProducer.cpp
@@ -150,10 +150,9 @@
 
 
     std::unordered_set<HashableDimensionKey> conditionDimensionsKeySet;
-    ConditionState conditionState = mWizard->getMetConditionDimension(
-        mConditionTrackerIndex, mDimensionsInCondition, &conditionDimensionsKeySet);
+    mWizard->getMetConditionDimension(mConditionTrackerIndex, mDimensionsInCondition,
+                                      &conditionDimensionsKeySet);
 
-    bool condition = (conditionState == ConditionState::kTrue);
     for (auto& pair : mCurrentSlicedDurationTrackerMap) {
         conditionDimensionsKeySet.erase(pair.first.getDimensionKeyInCondition());
     }
diff --git a/cmds/statsd/src/metrics/GaugeMetricProducer.cpp b/cmds/statsd/src/metrics/GaugeMetricProducer.cpp
index da0cafe..b5a9294 100644
--- a/cmds/statsd/src/metrics/GaugeMetricProducer.cpp
+++ b/cmds/statsd/src/metrics/GaugeMetricProducer.cpp
@@ -333,7 +333,6 @@
 }
 
 void GaugeMetricProducer::updateCurrentSlicedBucketForAnomaly() {
-    status_t err = NO_ERROR;
     for (const auto& slice : *mCurrentSlicedBucket) {
         if (slice.second.empty()) {
             continue;
diff --git a/cmds/statsd/src/metrics/duration_helper/MaxDurationTracker.cpp b/cmds/statsd/src/metrics/duration_helper/MaxDurationTracker.cpp
index c29876b..95df5ae6 100644
--- a/cmds/statsd/src/metrics/duration_helper/MaxDurationTracker.cpp
+++ b/cmds/statsd/src/metrics/duration_helper/MaxDurationTracker.cpp
@@ -177,7 +177,6 @@
             false;  // has either a kStarted or kPaused event across bucket boundaries
     // meaning we need to carry them over to the new bucket.
     for (auto it = mInfos.begin(); it != mInfos.end(); ++it) {
-        int64_t finalDuration = it->second.lastDuration;
         if (it->second.state == DurationState::kStopped) {
             // No need to keep buckets for events that were stopped before.
             mInfos.erase(it);
diff --git a/cmds/statsd/src/stats_log_util.cpp b/cmds/statsd/src/stats_log_util.cpp
index 86c258b..98ac262 100644
--- a/cmds/statsd/src/stats_log_util.cpp
+++ b/cmds/statsd/src/stats_log_util.cpp
@@ -39,15 +39,12 @@
 const int DIMENSIONS_VALUE_VALUE_STR = 2;
 const int DIMENSIONS_VALUE_VALUE_INT = 3;
 const int DIMENSIONS_VALUE_VALUE_LONG = 4;
-const int DIMENSIONS_VALUE_VALUE_BOOL = 5;
+// const int DIMENSIONS_VALUE_VALUE_BOOL = 5; // logd doesn't have bool data type.
 const int DIMENSIONS_VALUE_VALUE_FLOAT = 6;
 const int DIMENSIONS_VALUE_VALUE_TUPLE = 7;
 
 const int DIMENSIONS_VALUE_TUPLE_VALUE = 1;
 
-// for MessageValue Proto
-const int FIELD_ID_FIELD_VALUE_IN_MESSAGE_VALUE_PROTO = 1;
-
 // for PulledAtomStats proto
 const int FIELD_ID_PULLED_ATOM_STATS = 10;
 const int FIELD_ID_PULL_ATOM_ID = 1;
@@ -129,11 +126,6 @@
     protoOutput->end(topToken);
 }
 
-// for Field Proto
-const int FIELD_FIELD = 1;
-const int FIELD_POSITION_INDEX = 2;
-const int FIELD_CHILD = 3;
-
 // Supported Atoms format
 // XYZ_Atom {
 //     repeated SubMsg field_1 = 1;