From 5395b2af579e71d26706a1fa9db02a969aea558e Mon Sep 17 00:00:00 2001
From: Felipe Leme <felipeal@google.com>
Date: Fri, 19 Mar 2021 12:37:39 -0700
Subject: [PATCH] Lazy load the allocation of Slog message formatting objects.

Test: manual verification looking at logcat output
Fixes: 182963900

Change-Id: If62ccfe085b20cda8755fefc3ec757ad59986685
---
 core/java/android/util/Slog.java | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/core/java/android/util/Slog.java b/core/java/android/util/Slog.java
index f61ab29851635..d3eaeae993e68 100644
--- a/core/java/android/util/Slog.java
+++ b/core/java/android/util/Slog.java
@@ -30,11 +30,11 @@ import java.util.Locale;
  */
 public final class Slog {
 
-    @GuardedBy("sMessageBuilder")
-    private static final StringBuilder sMessageBuilder = new StringBuilder();
+    @GuardedBy("Slog.class")
+    private static StringBuilder sMessageBuilder;
 
-    @GuardedBy("sMessageBuilder")
-    private static final Formatter sFormatter = new Formatter(sMessageBuilder, Locale.ENGLISH);
+    @GuardedBy("Slog.class")
+    private static Formatter sFormatter;
 
     private Slog() {
     }
@@ -226,7 +226,12 @@ public final class Slog {
     }
 
     private static String getMessage(String format, @Nullable Object... args) {
-        synchronized (sMessageBuilder) {
+        synchronized (Slog.class) {
+            if (sMessageBuilder == null) {
+                // Lazy load so they're not created if not used by the process
+                sMessageBuilder = new StringBuilder();
+                sFormatter = new Formatter(sMessageBuilder, Locale.ENGLISH);
+            }
             sFormatter.format(format, args);
             String message = sMessageBuilder.toString();
             sMessageBuilder.setLength(0);