Revert^10 "Thread suspension cleanup and deadlock fix"""

This reverts commit 63af30b8fe8d4e1dc32db4dcb5e5dae1efdc7f31.

master (aosp/2530206) PS1 is identical to aosp/2377951 .

master (aosp/2530206) PS2 is a rebase.

At this point, master branch was replaced by main, and this CL moved.

PS1: Restructure documentation for the IncrementSuspendCount handshake
     to install a suspend barrier.
     Document a couple of additional mutator lock assumptions.
     Add some DCHECKs to check that suspended threads really are
     suspended.
     Weaken seq_cst memory order in a couple of places where it really
     didn't make sense here. Clearly not a correctness fix.
     Includes a rebase and merge with aosp/2587606.
PS2: Another rebase.
     Fix thumb assembler test to compensate for Thread structure layout
     changes.
PS3: Messy rebase, primarily to handle aosp/2670108, which included both
     new fixes around this and a few small snippets of this CL.
     Call EnsureFlipFunctionStarted without a state-and-flags argument
     only when we actually hold the mutator lock, as promised.
PS4: Minor rebase, some lint fixes.
PS5: Another minor lint fix that I had missed in PS4.
PS6: Fix for RunCheckpoint bug introduced around PS3. Fix expectations
     in jni_cfi_test to compensate for thread structure layout changes.
PS7: In PS3+, EnsureFlipFunctionStarted could access a destroyed "this"
     thread. Fix that, and make the function static to make this
     constraint more explicit. (And running a method on a potentially
     destroyed object just seemed unclean.)
PS8: Address reviewer comments. The major issue was that we released
     the suspend_count_lock too early in FlipThreadRoots, potentially
     allowing an intervening SuspendAll to block us. The fix involved
     a very minor extention of the mutex API.
PS9: Comment typo fix.
PS10: Address new reviewer comments. Rebase.

MUST_SLEEP for 129_ThreadGetId debug output.
Test: Treehugger.
Bug: 240742796
Bug: 203363895
Bug: 238032384
Bug: 253671779
Bug: 276660630
(and more)

Change-Id: I0f2450e394c03c17eece3698286b2f3e45727967

1 files changed, 9 insertions, 0 deletions

diff --git a/runtime/mirror/object.h b/runtime/mirror/object.h
index 95b9f86a4b..5e770f45a5 100644
--- a/runtime/mirror/object.h
+++ b/runtime/mirror/object.h
@@ -137,11 +137,16 @@ class MANAGED LOCKABLE Object {
       REQUIRES_SHARED(Locks::mutator_lock_)
       REQUIRES(!Roles::uninterruptible_);
 
+  // Returns a nonzero value that fits into lockword slot.
   int32_t IdentityHashCode()
       REQUIRES_SHARED(Locks::mutator_lock_)
       REQUIRES(!Locks::thread_list_lock_,
                !Locks::thread_suspend_count_lock_);
 
+  // Identical to the above, but returns 0 if monitor inflation would otherwise be needed.
+  int32_t IdentityHashCodeNoInflation() REQUIRES_SHARED(Locks::mutator_lock_)
+      REQUIRES(!Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_);
+
   static constexpr MemberOffset MonitorOffset() {
     return OFFSET_OF_OBJECT_MEMBER(Object, monitor_);
   }
@@ -726,6 +731,10 @@ class MANAGED LOCKABLE Object {
       REQUIRES_SHARED(Locks::mutator_lock_);
 
  private:
+  template <bool kAllowInflation>
+  int32_t IdentityHashCodeHelper() REQUIRES_SHARED(Locks::mutator_lock_)
+      REQUIRES(!Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_);
+
   // Get a field with acquire semantics.
   template<typename kSize>
   ALWAYS_INLINE kSize GetFieldAcquire(MemberOffset field_offset)