diff --git a/native/Android.mk b/native/Android.mk
index c8342e3..4727b1e 100644
--- a/native/Android.mk
+++ b/native/Android.mk
@@ -3,6 +3,11 @@
 
 LOCAL_C_INCLUDES += $(LOCAL_PATH)/src
 
+LOCAL_CFLAGS += -Werror -Wall
+
+# To suppress compiler warnings for unused variables/functions used for debug features etc.
+LOCAL_CFLAGS += -Wno-unused-parameter -Wno-unused-function
+
 LOCAL_SRC_FILES := \
     jni/com_android_inputmethod_keyboard_ProximityInfo.cpp \
     jni/com_android_inputmethod_latin_BinaryDictionary.cpp \
diff --git a/native/src/bigram_dictionary.cpp b/native/src/bigram_dictionary.cpp
index 5ec310f..36761b8 100644
--- a/native/src/bigram_dictionary.cpp
+++ b/native/src/bigram_dictionary.cpp
@@ -30,8 +30,10 @@
     : DICT(dict), MAX_WORD_LENGTH(maxWordLength),
     MAX_ALTERNATIVES(maxAlternatives), IS_LATEST_DICT_VERSION(isLatestDictVersion),
     HAS_BIGRAM(hasBigram), mParentDictionary(parentDictionary) {
-    if (DEBUG_DICT) LOGI("BigramDictionary - constructor");
-    if (DEBUG_DICT) LOGI("Has Bigram : %d", hasBigram);
+    if (DEBUG_DICT) {
+        LOGI("BigramDictionary - constructor");
+        LOGI("Has Bigram : %d", hasBigram);
+    }
 }
 
 BigramDictionary::~BigramDictionary() {
@@ -54,7 +56,9 @@
         }
         insertAt++;
     }
-    if (DEBUG_DICT) LOGI("Bigram: InsertAt -> %d maxBigrams: %d", insertAt, mMaxBigrams);
+    if (DEBUG_DICT) {
+        LOGI("Bigram: InsertAt -> %d maxBigrams: %d", insertAt, mMaxBigrams);
+    }
     if (insertAt < mMaxBigrams) {
         memmove((char*) mBigramFreq + (insertAt + 1) * sizeof(mBigramFreq[0]),
                (char*) mBigramFreq + insertAt * sizeof(mBigramFreq[0]),
@@ -68,7 +72,9 @@
             *dest++ = *word++;
         }
         *dest = 0; // NULL terminate
-        if (DEBUG_DICT) LOGI("Bigram: Added word at %d", insertAt);
+        if (DEBUG_DICT) {
+            LOGI("Bigram: Added word at %d", insertAt);
+        }
         return true;
     }
     return false;
@@ -107,7 +113,9 @@
     if (HAS_BIGRAM && IS_LATEST_DICT_VERSION) {
         int pos = mParentDictionary->isValidWordRec(
                 DICTIONARY_HEADER_SIZE, prevWord, 0, prevWordLength);
-        if (DEBUG_DICT) LOGI("Pos -> %d", pos);
+        if (DEBUG_DICT) {
+            LOGI("Pos -> %d", pos);
+        }
         if (pos < 0) {
             return 0;
         }
@@ -151,7 +159,9 @@
         }
         pos = followDownBranchAddress; // pos start at count
         int count = DICT[pos] & 0xFF;
-        if (DEBUG_DICT) LOGI("count - %d",count);
+        if (DEBUG_DICT) {
+            LOGI("count - %d",count);
+        }
         pos++;
         for (int i = 0; i < count; i++) {
             // pos at data
@@ -225,7 +235,9 @@
         }
         depth++;
         if (followDownBranchAddress == 0) {
-            if (DEBUG_DICT) LOGI("ERROR!!! Cannot find bigram!!");
+            if (DEBUG_DICT) {
+                LOGI("ERROR!!! Cannot find bigram!!");
+            }
             break;
         }
     }
diff --git a/native/src/defines.h b/native/src/defines.h
index 00cbb6c..9261207 100644
--- a/native/src/defines.h
+++ b/native/src/defines.h
@@ -77,8 +77,8 @@
 }
 
 #else // FLAG_DBG
-#define LOGE
-#define LOGI
+#define LOGE(fmt, ...)
+#define LOGI(fmt, ...)
 #define DEBUG_DICT false
 #define DEBUG_DICT_FULL false
 #define DEBUG_SHOW_FOUND_WORD false
diff --git a/native/src/proximity_info.h b/native/src/proximity_info.h
index 0f12018..c2062e8 100644
--- a/native/src/proximity_info.h
+++ b/native/src/proximity_info.h
@@ -32,13 +32,13 @@
     bool hasSpaceProximity(const int x, const int y) const;
 private:
     int getStartIndexFromCoordinates(const int x, const int y) const;
-    const int CELL_WIDTH;
-    const int CELL_HEIGHT;
+    const int MAX_PROXIMITY_CHARS_SIZE;
     const int KEYBOARD_WIDTH;
     const int KEYBOARD_HEIGHT;
     const int GRID_WIDTH;
     const int GRID_HEIGHT;
-    const int MAX_PROXIMITY_CHARS_SIZE;
+    const int CELL_WIDTH;
+    const int CELL_HEIGHT;
     uint32_t *mProximityCharsArray;
 };
 }; // namespace latinime
diff --git a/native/src/unigram_dictionary.cpp b/native/src/unigram_dictionary.cpp
index 30fbaea..c188290 100644
--- a/native/src/unigram_dictionary.cpp
+++ b/native/src/unigram_dictionary.cpp
@@ -43,7 +43,9 @@
     ROOT_POS(isLatestDictVersion ? DICTIONARY_HEADER_SIZE : 0),
     BYTES_IN_ONE_CHAR(MAX_PROXIMITY_CHARS * sizeof(*mInputCodes)),
     MAX_UMLAUT_SEARCH_DEPTH(DEFAULT_MAX_UMLAUT_SEARCH_DEPTH) {
-    if (DEBUG_DICT) LOGI("UnigramDictionary - constructor");
+    if (DEBUG_DICT) {
+        LOGI("UnigramDictionary - constructor");
+    }
 }
 
 UnigramDictionary::~UnigramDictionary() {}
@@ -183,7 +185,9 @@
     // Suggestion with missing character
     if (SUGGEST_WORDS_WITH_MISSING_CHARACTER) {
         for (int i = 0; i < codesSize; ++i) {
-            if (DEBUG_DICT) LOGI("--- Suggest missing characters %d", i);
+            if (DEBUG_DICT) {
+                LOGI("--- Suggest missing characters %d", i);
+            }
             getSuggestionCandidates(i, -1, -1, NULL, 0, MAX_DEPTH);
         }
     }
@@ -194,7 +198,9 @@
     if (SUGGEST_WORDS_WITH_EXCESSIVE_CHARACTER
             && mInputLength >= MIN_USER_TYPED_LENGTH_FOR_EXCESSIVE_CHARACTER_SUGGESTION) {
         for (int i = 0; i < codesSize; ++i) {
-            if (DEBUG_DICT) LOGI("--- Suggest excessive characters %d", i);
+            if (DEBUG_DICT) {
+                LOGI("--- Suggest excessive characters %d", i);
+            }
             getSuggestionCandidates(-1, i, -1, NULL, 0, MAX_DEPTH);
         }
     }
@@ -205,7 +211,9 @@
     // Only suggest words that length is mInputLength
     if (SUGGEST_WORDS_WITH_TRANSPOSED_CHARACTERS) {
         for (int i = 0; i < codesSize; ++i) {
-            if (DEBUG_DICT) LOGI("--- Suggest transposed characters %d", i);
+            if (DEBUG_DICT) {
+                LOGI("--- Suggest transposed characters %d", i);
+            }
             getSuggestionCandidates(-1, -1, i, NULL, 0, mInputLength - 1);
         }
     }
@@ -216,7 +224,9 @@
     if (SUGGEST_WORDS_WITH_MISSING_SPACE_CHARACTER
             && mInputLength >= MIN_USER_TYPED_LENGTH_FOR_MISSING_SPACE_SUGGESTION) {
         for (int i = 1; i < codesSize; ++i) {
-            if (DEBUG_DICT) LOGI("--- Suggest missing space characters %d", i);
+            if (DEBUG_DICT) {
+                LOGI("--- Suggest missing space characters %d", i);
+            }
             getMissingSpaceWords(mInputLength, i);
         }
     }
@@ -226,12 +236,15 @@
     if (SUGGEST_WORDS_WITH_SPACE_PROXIMITY) {
         // The first and last "mistyped spaces" are taken care of by excessive character handling
         for (int i = 1; i < codesSize - 1; ++i) {
-            if (DEBUG_DICT) LOGI("--- Suggest words with proximity space %d", i);
+            if (DEBUG_DICT) {
+                LOGI("--- Suggest words with proximity space %d", i);
+            }
             const int x = xcoordinates[i];
             const int y = ycoordinates[i];
-            if (DEBUG_PROXIMITY_INFO)
+            if (DEBUG_PROXIMITY_INFO) {
                 LOGI("Input[%d] x = %d, y = %d, has space proximity = %d",
                         i, x, y, proximityInfo->hasSpaceProximity(x, y));
+            }
             if (proximityInfo->hasSpaceProximity(x, y)) {
                 getMistypedSpaceWords(mInputLength, i);
             }
@@ -242,7 +255,9 @@
 
 void UnigramDictionary::initSuggestions(const int *codes, const int codesSize,
         unsigned short *outWords, int *frequencies) {
-    if (DEBUG_DICT) LOGI("initSuggest");
+    if (DEBUG_DICT) {
+        LOGI("initSuggest");
+    }
     mFrequencies = frequencies;
     mOutputChars = outWords;
     mInputCodes = codes;
@@ -266,7 +281,9 @@
         LOGI("Found word = %s, freq = %d", s, frequency);
     }
     if (length > MAX_WORD_LENGTH) {
-        if (DEBUG_DICT) LOGI("Exceeded max word length.");
+        if (DEBUG_DICT) {
+            LOGI("Exceeded max word length.");
+        }
         return false;
     }
 
@@ -297,7 +314,9 @@
             *dest++ = *word++;
         }
         *dest = 0; // NULL terminate
-        if (DEBUG_DICT) LOGI("Added word at %d", insertAt);
+        if (DEBUG_DICT) {
+            LOGI("Added word at %d", insertAt);
+        }
         return true;
     }
     return false;
@@ -409,7 +428,9 @@
     // Allocating variable length array on stack
     unsigned short word[newWordLength];
     const int firstFreq = getBestWordFreq(firstWordStartPos, firstWordLength, mWord);
-    if (DEBUG_DICT) LOGI("First freq: %d", firstFreq);
+    if (DEBUG_DICT) {
+        LOGI("First freq: %d", firstFreq);
+    }
     if (firstFreq <= 0) return false;
 
     for (int i = 0; i < firstWordLength; ++i) {
@@ -417,7 +438,9 @@
     }
 
     const int secondFreq = getBestWordFreq(secondWordStartPos, secondWordLength, mWord);
-    if (DEBUG_DICT) LOGI("Second  freq:  %d", secondFreq);
+    if (DEBUG_DICT) {
+        LOGI("Second  freq:  %d", secondFreq);
+    }
     if (secondFreq <= 0) return false;
 
     word[firstWordLength] = SPACE;
@@ -514,7 +537,9 @@
     for (int i = 0; i < depth; ++i) lengthFreq *= TYPED_LETTER_MULTIPLIER;
     if (lengthFreq == matchWeight) {
         if (depth > 1) {
-            if (DEBUG_DICT) LOGI("Found full matched word.");
+            if (DEBUG_DICT) {
+                LOGI("Found full matched word.");
+            }
             multiplyRate(FULL_MATCHED_WORDS_PROMOTION_RATE, &finalFreq);
         }
         if (sameLength && transposedPos < 0 && skipPos < 0 && excessivePos < 0) {
@@ -768,7 +793,9 @@
     *siblingPos = Dictionary::setDictionaryValues(DICT, IS_LATEST_DICT_VERSION, firstChildPos, &c,
             newChildPosition, newTerminal, newFreq);
     const unsigned int inputC = currentChars[0];
-    if (DEBUG_DICT) assert(inputC <= U_SHORT_MAX);
+    if (DEBUG_DICT) {
+        assert(inputC <= U_SHORT_MAX);
+    }
     const unsigned short baseLowerC = toBaseLowerCase(c);
     const bool matched = (inputC == baseLowerC || inputC == c);
     const bool hasChild = *newChildPosition != 0;
@@ -776,7 +803,9 @@
         word[depth] = c;
         if (DEBUG_DICT && DEBUG_NODE) {
             LOGI("Node(%c, %c)<%d>, %d, %d", inputC, c, matched, hasChild, *newFreq);
-            if (*newTerminal) LOGI("Terminal %d", *newFreq);
+            if (*newTerminal) {
+                LOGI("Terminal %d", *newFreq);
+            }
         }
         if (hasChild) {
             *newCount = Dictionary::getCount(DICT, newChildPosition);