AudioFlinger: Move NBLog thread_local to no linkage.

Access the thread_local by getter/setter only.
This prevents a memory leak with the clang compiler.

Test: adb shell dumpsys media.audio_flinger --unreachable
Bug: 284657986
Merged-In: Ic7128eea2aef47289c6e38ebca6fb5292d919410
Change-Id: Ic7128eea2aef47289c6e38ebca6fb5292d919410
(cherry picked from commit 5a5b514ac4673a82f665ebc230174a6a4a802632)
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 20f9470..654f506 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -3833,7 +3833,7 @@
 bool AudioFlinger::PlaybackThread::threadLoop()
 NO_THREAD_SAFETY_ANALYSIS  // manual locking of AudioFlinger
 {
-    tlNBLogWriter = mNBLogWriter.get();
+    aflog::setThreadWriter(mNBLogWriter.get());
 
     Vector< sp<Track> > tracksToRemove;
 
diff --git a/services/audioflinger/afutils/TypedLogger.cpp b/services/audioflinger/afutils/TypedLogger.cpp
index 57c206b..7c546a5 100644
--- a/services/audioflinger/afutils/TypedLogger.cpp
+++ b/services/audioflinger/afutils/TypedLogger.cpp
@@ -22,6 +22,25 @@
 #include <pthread.h>
 #include "TypedLogger.h"
 
-namespace android {
+namespace android::aflog {
+
+// External linkage access of thread local storage outside of this shared library
+// causes orphaned memory allocations.  This occurs in the implementation of
+// __emutls_get_address(), see b/284657986.
+//
+// We only expose a thread local storage getter and setter here, not the
+// actual thread local variable.
+
+namespace {
 thread_local NBLog::Writer *tlNBLogWriter;
+} // namespace
+
+NBLog::Writer *getThreadWriter() {
+    return tlNBLogWriter;
 }
+
+void setThreadWriter(NBLog::Writer *writer) {
+    tlNBLogWriter = writer;
+}
+
+} // namespace android::aflog
diff --git a/services/audioflinger/afutils/TypedLogger.h b/services/audioflinger/afutils/TypedLogger.h
index feb71e3..f34a50c 100644
--- a/services/audioflinger/afutils/TypedLogger.h
+++ b/services/audioflinger/afutils/TypedLogger.h
@@ -85,56 +85,57 @@
 //      slower than nullptr check when logging is enabled at compile-time and disabled at runtime.
 
 // Write formatted entry to log
-#define LOGT(fmt, ...) do { NBLog::Writer *x = tlNBLogWriter; if (x != nullptr) \
+#define LOGT(fmt, ...) do { NBLog::Writer *x = aflog::getThreadWriter(); if (x != nullptr) \
                                 x->logFormat((fmt), hash(__FILE__, __LINE__), ##__VA_ARGS__); } \
                                 while (0)
 
 // Write histogram timestamp entry
-#define LOG_HIST_TS() do { NBLog::Writer *x = tlNBLogWriter; if (x != nullptr) \
+#define LOG_HIST_TS() do { NBLog::Writer *x = aflog::getThreadWriter(); if (x != nullptr) \
         x->logEventHistTs(NBLog::EVENT_HISTOGRAM_ENTRY_TS, hash(__FILE__, __LINE__)); } while(0)
 
 // Record that audio was turned on/off
-#define LOG_AUDIO_STATE() do { NBLog::Writer *x = tlNBLogWriter; if (x != nullptr) \
+#define LOG_AUDIO_STATE() do { NBLog::Writer *x = aflog::getThreadWriter(); if (x != nullptr) \
         x->logEventHistTs(NBLog::EVENT_AUDIO_STATE, hash(__FILE__, __LINE__)); } while(0)
 
 // Log the difference bewteen frames presented by HAL and frames written to HAL output sink,
 // divided by the sample rate. Parameter ms is of type double.
-#define LOG_LATENCY(ms) do { NBLog::Writer *x = tlNBLogWriter; if (x != nullptr) \
+#define LOG_LATENCY(ms) do { NBLog::Writer *x = aflog::getThreadWriter(); if (x != nullptr) \
         x->log<NBLog::EVENT_LATENCY>(ms); } while (0)
 
 // Record thread overrun event nanosecond timestamp. Parameter ns is an int64_t.
-#define LOG_OVERRUN(ns) do { NBLog::Writer *x = tlNBLogWriter; if (x != nullptr) \
+#define LOG_OVERRUN(ns) do { NBLog::Writer *x = aflog::getThreadWriter(); if (x != nullptr) \
         x->log<NBLog::EVENT_OVERRUN>(ns); } while (0)
 
 // Record thread info. This currently includes type, frameCount, and sampleRate.
 // Parameter type is thread_info_t as defined in NBLog.h.
-#define LOG_THREAD_INFO(info) do { NBLog::Writer *x = tlNBLogWriter; \
+#define LOG_THREAD_INFO(info) do { NBLog::Writer *x = aflog::getThreadWriter(); \
         if (x != nullptr) x->log<NBLog::EVENT_THREAD_INFO>(info); } while (0)
 
-#define LOG_THREAD_PARAMS(params) do {NBLog::Writer *x = tlNBLogWriter; \
+#define LOG_THREAD_PARAMS(params) do {NBLog::Writer *x = aflog::getThreadWriter(); \
         if (x != nullptr) x->log<NBLog::EVENT_THREAD_PARAMS>(params); } while (0)
 
 // Record thread underrun event nanosecond timestamp. Parameter ns is an int64_t.
-#define LOG_UNDERRUN(ns) do { NBLog::Writer *x = tlNBLogWriter; if (x != nullptr) \
+#define LOG_UNDERRUN(ns) do { NBLog::Writer *x = aflog::getThreadWriter(); if (x != nullptr) \
         x->log<NBLog::EVENT_UNDERRUN>(ns); } while (0)
 
 // Record thread warmup time in milliseconds. Parameter ms is of type double.
-#define LOG_WARMUP_TIME(ms) do { NBLog::Writer *x = tlNBLogWriter; if (x != nullptr) \
+#define LOG_WARMUP_TIME(ms) do { \
+        NBLog::Writer *x = aflog::getThreadWriter(); if (x != nullptr) \
         x->log<NBLog::EVENT_WARMUP_TIME>(ms); } while (0)
 
 // Record a typed entry that represents a thread's work time in nanoseconds.
 // Parameter ns should be of type uint32_t.
-#define LOG_WORK_TIME(ns) do { NBLog::Writer *x = tlNBLogWriter; if (x != nullptr) \
+#define LOG_WORK_TIME(ns) do { NBLog::Writer *x = aflog::getThreadWriter(); if (x != nullptr) \
         x->log<NBLog::EVENT_WORK_TIME>(ns); } while (0)
 
-namespace android {
-extern "C" {
+namespace android::aflog {
 // TODO consider adding a thread_local NBLog::Writer tlStubNBLogWriter and then
-// initialize below tlNBLogWriter to &tlStubNBLogWriter to remove the need to
+// initialize setThreadWriter() to &tlStubNBLogWriter to remove the need to
 // check for nullptr every time. Also reduces the need to add a new logging macro above
 // each time we want to log a new type.
-extern thread_local NBLog::Writer *tlNBLogWriter;
-}
-} // namespace android
+
+NBLog::Writer *getThreadWriter();
+void setThreadWriter(NBLog::Writer *writer);
+} // namespace android::aflog
 
 #endif // ANDROID_TYPED_LOGGER_H
diff --git a/services/audioflinger/fastpath/FastThread.cpp b/services/audioflinger/fastpath/FastThread.cpp
index 77071dc..2ebdbc1 100644
--- a/services/audioflinger/fastpath/FastThread.cpp
+++ b/services/audioflinger/fastpath/FastThread.cpp
@@ -88,7 +88,7 @@
 {
     // LOGT now works even if tlNBLogWriter is nullptr, but we're considering changing that,
     // so this initialization permits a future change to remove the check for nullptr.
-    tlNBLogWriter = mDummyNBLogWriter.get();
+    aflog::setThreadWriter(mDummyNBLogWriter.get());
     for (;;) {
 
         // either nanosleep, sched_yield, or busy wait
@@ -118,9 +118,10 @@
 
             // As soon as possible of learning of a new dump area, start using it
             mDumpState = next->mDumpState != nullptr ? next->mDumpState : mDummyDumpState;
-            tlNBLogWriter = next->mNBLogWriter != nullptr ?
+            NBLog::Writer * const writer = next->mNBLogWriter != nullptr ?
                     next->mNBLogWriter : mDummyNBLogWriter.get();
-            setNBLogWriter(tlNBLogWriter); // This is used for debugging only
+            aflog::setThreadWriter(writer);
+            setNBLogWriter(writer); // This is used for debugging only
 
             // We want to always have a valid reference to the previous (non-idle) state.
             // However, the state queue only guarantees access to current and previous states.