From d3c72db3bb210939ca9ff814577e00111baf4018 Mon Sep 17 00:00:00 2001
From: Mathieu Chartier <mathieuc@google.com>
Date: Wed, 23 Oct 2019 09:53:39 -0700
Subject: [PATCH] Avoid preloading classes for boot image profiling

Since the clinits may execute methods, we should avoid preloading
classes to avoid executing methods that may not be required. These
samples could cause inaccuracy in the boot image profile.

Test: manual: adb logcat | grep preloadClasses
Bug: 139883463

Change-Id: I5b4568a477724606105196cba010109f80eecec1
---
 core/java/com/android/internal/os/ZygoteInit.java | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/core/java/com/android/internal/os/ZygoteInit.java b/core/java/com/android/internal/os/ZygoteInit.java
index 72d24645a2e7e..ad4c6dd7a92b3 100644
--- a/core/java/com/android/internal/os/ZygoteInit.java
+++ b/core/java/com/android/internal/os/ZygoteInit.java
@@ -248,6 +248,18 @@ public class ZygoteInit {
 
         InputStream is;
         try {
+            // If we are profiling the boot image, avoid preloading classes.
+            // Can't use device_config since we are the zygote.
+            String prop = SystemProperties.get(
+                    "persist.device_config.runtime_native_boot.profilebootclasspath", "");
+            // Might be empty if the property is unset since the default is "".
+            if (prop.length() == 0) {
+                prop = SystemProperties.get("dalvik.vm.profilebootclasspath", "");
+            }
+            if ("true".equals(prop)) {
+                return;
+            }
+
             is = new FileInputStream(PRELOADED_CLASSES);
         } catch (FileNotFoundException e) {
             Log.e(TAG, "Couldn't find " + PRELOADED_CLASSES + ".");