diff --git a/Android.bp b/Android.bp
index e404cd0372ec4..b28567af0b778 100644
--- a/Android.bp
+++ b/Android.bp
@@ -34,6 +34,11 @@ cc_library {
         include_dirs: ["external/protobuf/src"],
     },
 
+    cflags: [
+        "-Wall",
+        "-Werror",
+        "-Wno-unused-parameter",
+    ],
     target: {
         host: {
             proto: {
diff --git a/cmds/am/Android.bp b/cmds/am/Android.bp
index 7eb4edfecbf92..bb16df1d159dc 100644
--- a/cmds/am/Android.bp
+++ b/cmds/am/Android.bp
@@ -4,6 +4,7 @@
 cc_library_host_static {
     name: "libinstrumentation",
     srcs: ["**/*.proto"],
+    cflags: ["-Wall", "-Werror"],
     proto: {
         type: "full",
         export_proto_headers: true,
diff --git a/tools/bit/Android.bp b/tools/bit/Android.bp
index 258e9b517f6d1..a8062719d586e 100644
--- a/tools/bit/Android.bp
+++ b/tools/bit/Android.bp
@@ -30,6 +30,11 @@ cc_binary_host {
         "util.cpp",
     ],
 
+    cflags: [
+        "-Wall",
+        "-Werror",
+    ],
+
     static_libs: [
         "libexpat",
         "libinstrumentation",
diff --git a/tools/bit/adb.cpp b/tools/bit/adb.cpp
index c8faf5c667228..fa7d3d4031d41 100644
--- a/tools/bit/adb.cpp
+++ b/tools/bit/adb.cpp
@@ -302,7 +302,9 @@ run_instrumentation_test(const string& packageName, const string& runner, const
     print_command(cmd);
 
     int fds[2];
-    pipe(fds);
+    if (0 != pipe(fds)) {
+        return errno;
+    }
 
     pid_t pid = fork();
 
diff --git a/tools/bit/command.cpp b/tools/bit/command.cpp
index 9a8449bf9356f..1ff7c221b26e7 100644
--- a/tools/bit/command.cpp
+++ b/tools/bit/command.cpp
@@ -105,7 +105,9 @@ get_command_output(const Command& command, int* err, bool quiet)
     }
 
     int fds[2];
-    pipe(fds);
+    if (0 != pipe(fds)) {
+        return string();
+    }
 
     pid_t pid = fork();
 
diff --git a/tools/bit/main.cpp b/tools/bit/main.cpp
index 91ca5143965e6..a8a4cfcab3513 100644
--- a/tools/bit/main.cpp
+++ b/tools/bit/main.cpp
@@ -596,6 +596,15 @@ check_device_property(const string& property, const string& expected)
     }
 }
 
+static void
+chdir_or_exit(const char *path) {
+    // TODO: print_command("cd", path);
+    if (0 != chdir(path)) {
+        print_error("Error: Could not chdir: %s", path);
+        exit(1);
+    }
+}
+
 /**
  * Run the build, install, and test actions.
  */
@@ -618,8 +627,7 @@ run_phases(vector<Target*> targets, const Options& options)
     const string buildId = get_build_var(buildTop, "BUILD_ID", false);
     const string buildOut = get_out_dir();
 
-    // TODO: print_command("cd", buildTop.c_str());
-    chdir(buildTop.c_str());
+    chdir_or_exit(buildTop.c_str());
 
     // Get the modules for the targets
     map<string,Module> modules;
@@ -999,7 +1007,7 @@ run_tab_completion(const string& word)
     const string buildProduct = get_required_env("TARGET_PRODUCT", false);
     const string buildOut = get_out_dir();
 
-    chdir(buildTop.c_str());
+    chdir_or_exit(buildTop.c_str());
 
     string buildDevice = sniff_device_name(buildOut, buildProduct);
 
diff --git a/tools/bit/util.cpp b/tools/bit/util.cpp
index fc93bcb8c935d..922393146b103 100644
--- a/tools/bit/util.cpp
+++ b/tools/bit/util.cpp
@@ -101,7 +101,6 @@ TrackedFile::HasChanged() const
 void
 get_directory_contents(const string& name, map<string,FileInfo>* results)
 {
-    int err;
     DIR* dir = opendir(name.c_str());
     if (dir == NULL) {
         return;
@@ -241,7 +240,9 @@ read_file(const string& filename)
     fseek(file, 0, SEEK_SET);
 
     char* buf = (char*)malloc(size);
-    fread(buf, 1, size, file);
+    if ((size_t) size != fread(buf, 1, size, file)) {
+        return string();
+    }
 
     string result(buf, size);
 
diff --git a/tools/incident_report/Android.bp b/tools/incident_report/Android.bp
index ab55dbd818212..f2d0d0f3e5534 100644
--- a/tools/incident_report/Android.bp
+++ b/tools/incident_report/Android.bp
@@ -31,5 +31,5 @@ cc_binary_host {
         "libprotobuf-cpp-full",
     ],
 
-    cflags: ["-Wno-unused-parameter"],
+    cflags: ["-Wall", "-Werror"],
 }
diff --git a/tools/incident_report/printer.cpp b/tools/incident_report/printer.cpp
index bd660dd20dfd1..bff1025ad8da6 100644
--- a/tools/incident_report/printer.cpp
+++ b/tools/incident_report/printer.cpp
@@ -70,7 +70,6 @@ Out::printf(const char* format, ...)
 
     len = vsnprintf(mBuf, mBufSize, format, args);
     va_end(args);
-    bool truncated = (len >= mBufSize) && (reallocate(len) < len);
 
     va_start(args, format);
     len = vsnprintf(mBuf, mBufSize, format, args);
diff --git a/tools/incident_section_gen/Android.bp b/tools/incident_section_gen/Android.bp
index 1756e06c66fae..f07445a17781b 100644
--- a/tools/incident_section_gen/Android.bp
+++ b/tools/incident_section_gen/Android.bp
@@ -22,6 +22,8 @@ cc_binary_host {
     cflags: [
         "-g",
         "-O0",
+        "-Wall",
+        "-Werror",
     ],
     srcs: ["main.cpp"],
     shared_libs: [