Remove inconsistent usage of macros that broke Thread.sleep/wait on host

Code for managing Thread.sleep/wait used both !defined(__APPLE__) and
HAVE_POSIX_CLOCKS interchangeably to mean the same thing. That worked when
one or other was set but failed on host because neither were set and could also
fail if they were both set. This changed to use HAVE_POSIX_CLOCKS consistently.

The code that used this was spread across 4 separate files with quite a lot of
duplication so that has been replaced with a new method
dvmInitCondForTimedWait in Sync.cpp.

A few extra comments were added to make some things that were a bit confusing
clearer, hopefully.

Change-Id: I7660c931f0cafcd0563afd1165de2aa615040602
Bug: https://code.google.com/p/android/issues/detail?id=68402

1 files changed, 17 insertions, 0 deletions

diff --git a/vm/Sync.cpp b/vm/Sync.cpp
index d2ef49fb5..c9a32d45f 100644
--- a/vm/Sync.cpp
+++ b/vm/Sync.cpp
@@ -550,9 +550,11 @@ static void absoluteTime(s8 msec, s4 nsec, struct timespec *ts)
 {
     s8 endSec;
 
+    // Clock used here must be consistent with clock specified in dvmInitCondForTimedWait
 #ifdef HAVE_POSIX_CLOCKS
     clock_gettime(CLOCK_MONOTONIC, ts);
 #else
+    // Platform (probably MacOS) doesn't support CLOCK_MONOTONIC
     {
         struct timeval tv;
         gettimeofday(&tv, NULL);
@@ -575,6 +577,20 @@ static void absoluteTime(s8 msec, s4 nsec, struct timespec *ts)
     }
 }
 
+void dvmInitCondForTimedWait(pthread_cond_t* cond)
+{
+    // Must be consistent with clock specified in absoluteTime
+#ifdef HAVE_POSIX_CLOCKS
+    pthread_condattr_t condAttr;
+    pthread_condattr_init(&condAttr);
+    pthread_condattr_setclock(&condAttr, CLOCK_MONOTONIC);
+    pthread_cond_init(cond, &condAttr);
+#else
+    // Platform (probably MacOS) doesn't support CLOCK_MONOTONIC or pthread_condattr_setclock
+    pthread_cond_init(cond, NULL);
+#endif
+}
+
 int dvmRelativeCondWait(pthread_cond_t* cond, pthread_mutex_t* mutex,
                         s8 msec, s4 nsec)
 {
@@ -640,6 +656,7 @@ static void waitMonitor(Thread* self, Monitor* mon, s8 msec, s4 nsec,
     if (msec == 0 && nsec == 0) {
         timed = false;
     } else {
+        // Calculate absolute time before doing any other work so it is as accurate as possible.
         absoluteTime(msec, nsec, &ts);
         timed = true;
     }