From 4c57596b811645d56301a8026489a500ead0852f Mon Sep 17 00:00:00 2001
From: Jiyong Park <jiyong@google.com>
Date: Tue, 25 Aug 2020 17:05:41 +0900
Subject: [PATCH] Don't enable version lib for libadb_sysdeps

When use_version_lib is set to true, but build::GetBuildNumber() isn't
used, the library can't be processed by symbol_inject. For example,

$ m out/soong/.intermediates/system/core/adb/libadb_sysdeps/android/arm64_armv8-a_shared/versioned/libadb_sysdeps.so

FAILED:
out/soong/.intermediates/system/core/adb/libadb_sysdeps/android_arm64_armv8-a_shared/versioned/libadb_sysdeps.so
out/soong/host/linux-x86/bin/symbol_inject -i
out/soong/.intermediates/system/core/adb/libadb_sysdeps/android_arm64_armv8-a_shared/unstripped/libadb_sysdeps.so
-o
out/soong/.intermediates/system/core/adb/libadb_sysdeps/android_arm64_armv8-a_shared/versioned/libadb_sysdeps.so
-s soong_build_number -from 'SOONG BUILD NUMBER PLACEHOLDER' -v $(cat
out/soong/build_number.txt)
symbol not found
17:09:10 ninja failed with: exit status 1

This is because the visibility of the symbol `soong_build_number` in
libbuildversion.a is hidden via the -fvisibility=hidden flag for the
library. In addition, -Wl,--gc-sections strips the hidden symbol when
it is not referenced.

This fortunately hasn't caused a problem because, for the device target,
the output of symbol_inject was used only for dist outputs.
libadb_sysdeps wasn't registered as dists. So
versioned/libadb_sysprops.so never had a chance to be built. For the
host target, in the other hand, the output of symbol_inject is used
always, but --gc-sections is not used for host targets. So the symbol
wasn't stripped and therefore symbol_inject could always find the
symbol.

This however is expected to cause a problem when the support for
LinuxCross is added. It is one of the host targets, therefore
symbol_inject is always used. However, unlike other host targets,
--gc-sections is turned on because it inherits most of the flags from
Android/ARM64.

To avoid the problem, we might want to disable --gc-sections for the
target. But regardless of the decision, having a build rule that always
fails is not desirable - even though the build rule is essentially never
triggered. Therefore, we choose to not use version lib for
libadb_sysdeps because GetBuildNumber() is not used in the lib.

Bug: 159685774
Test: m \
out/soong/.intermediates/system/core/adb/libadb_sysdeps/android/\
arm64_armv8-a_shared/versioned/libadb_sysdeps.so

Change-Id: Ide1056b5b55e409ab809e302a697d10d759c92ce
---
 adb/Android.bp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/adb/Android.bp b/adb/Android.bp
index 8addf95aa..5351b3fbb 100644
--- a/adb/Android.bp
+++ b/adb/Android.bp
@@ -270,6 +270,8 @@ cc_library {
     host_supported: true,
     compile_multilib: "both",
     min_sdk_version: "apex_inherit",
+    // This library doesn't use build::GetBuildNumber()
+    use_version_lib: false,
 
     srcs: [
         "sysdeps/env.cpp",