From bcaeacc6862be57f72ba1c51427214136c2e06df Mon Sep 17 00:00:00 2001
From: Christopher Ferris <cferris@google.com>
Date: Wed, 27 Mar 2024 16:17:50 -0700
Subject: [PATCH] Enable weak functions properly.

There is a check for WEAKS_AVAILABLE that is never set. Change this so
so it is available everywhere except apple/windows.

Add new test to verify that on Android the logStackInternal function is
defined.

Bug: 331489939

Test: All unit tests pass.
Change-Id: Ie982eba30ae421931a62718d39ff1f0c282453db
---
 libutils/CallStack.cpp      |  5 +++--
 libutils/CallStack_test.cpp | 41 +++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/libutils/CallStack.cpp b/libutils/CallStack.cpp
index fe827eb0e..029f4a76e 100644
--- a/libutils/CallStack.cpp
+++ b/libutils/CallStack.cpp
@@ -89,7 +89,8 @@ void CallStack::print(Printer& printer) const {
 // The following four functions may be used via weak symbol references from libutils.
 // Clients assume that if any of these symbols are available, then deleteStack() is.
 
-#ifdef WEAKS_AVAILABLE
+// Apple and Windows does not support this, so only compile on other platforms.
+#if !defined(__APPLE__) && !defined(_WIN32)
 
 CallStack::CallStackUPtr CallStack::getCurrentInternal(int ignoreDepth) {
     CallStack::CallStackUPtr stack(new CallStack());
@@ -110,6 +111,6 @@ void CallStack::deleteStack(CallStack* stack) {
     delete stack;
 }
 
-#endif // WEAKS_AVAILABLE
+#endif  // !defined(__APPLE__) && !defined(_WIN32)
 
 }; // namespace android
diff --git a/libutils/CallStack_test.cpp b/libutils/CallStack_test.cpp
index 2cfaf6127..7afc2c333 100644
--- a/libutils/CallStack_test.cpp
+++ b/libutils/CallStack_test.cpp
@@ -18,10 +18,16 @@
 
 #include <thread>
 
+#include <android-base/test_utils.h>
 #include <android-base/threads.h>
 #include <gtest/gtest.h>
 #include <utils/CallStack.h>
 
+#if defined(__ANDROID__)
+#include <log/log.h>
+#include <log/log_read.h>
+#endif
+
 __attribute__((__noinline__)) extern "C" void CurrentCaller(android::String8& backtrace) {
     android::CallStack cs;
     cs.update();
@@ -61,3 +67,38 @@ TEST(CallStackTest, thread_backtrace) {
 
     ASSERT_NE(-1, cs.toString().find("(ThreadBusyWait")) << "Full backtrace:\n" << cs.toString();
 }
+
+#if defined(__ANDROID__)
+TEST(CallStackTest, log_stack) {
+    android::CallStack::logStack("callstack_test");
+    auto logger_list = android_logger_list_open(android_name_to_log_id("main"),
+                                                ANDROID_LOG_NONBLOCK, 1000, getpid());
+    ASSERT_NE(nullptr, logger_list);
+    std::string log;
+    while (true) {
+        log_msg log_msg;
+        auto ret = android_logger_list_read(logger_list, &log_msg);
+        if (ret == -EAGAIN) {
+            break;
+        }
+        ASSERT_GT(ret, 0);
+        if (log_msg.msg() == nullptr) {
+            continue;
+        }
+        // First get the tag.
+        char* msg = &log_msg.msg()[1];
+        if (std::string(msg) != "callstack_test") {
+            continue;
+        }
+        // Now move past the tag.
+        msg = &msg[strlen(msg) + 1];
+        log += msg;
+        log += '\n';
+    }
+    ASSERT_NE("", log) << "No messages found in the log from the test.";
+    // Look for a backtrace line such as:
+    //   #00 pc 00000000000536e4  libutils_test (testing::Test::Run()+436)
+    ASSERT_MATCH(log, "#\\d+ pc \\d+");
+    android_logger_list_close(logger_list);
+}
+#endif