tsan: rearrange thread state callbacks (NFC)

[dvyukov]

Summary

Thread state functions are split into 2 parts:
tsan entry function (e.g. ThreadStart) and thread registry
state change callback (e.g. OnStart). Currently these
pairs of functions are located far from each other and
in reverse order. This makes it hard to read and follow the logic.
Reorder the code so that OnFoo directly follows ThreadFoo.
No other code changes.

compiler-rt/lib/tsan/rtl/tsan_rtl_thread.cpp

 ThreadContext::ThreadContext(Tid tid)
     : ThreadContextBase(tid), thr(), sync(), epoch0(), epoch1() {}
 
 #if !SANITIZER_GO
 ThreadContext::~ThreadContext() {
 }
 #endif
 
-void ThreadContext::OnDead() {
-  CHECK_EQ(sync.size(), 0);
-}
-
-void ThreadContext::OnJoined(void *arg) {
-  ThreadState *caller_thr = static_cast<ThreadState *>(arg);
-  AcquireImpl(caller_thr, 0, &sync);
-  sync.Reset(&caller_thr->proc()->clock_cache);
-}
-
-struct OnCreatedArgs {
-  ThreadState *thr;
-  uptr pc;
-};
-
-void ThreadContext::OnCreated(void *arg) {
-  thr = 0;
-  if (tid == kMainTid)
-    return;
-  OnCreatedArgs *args = static_cast<OnCreatedArgs *>(arg);
-  if (!args->thr)  // GCD workers don't have a parent thread.
-    return;
-  args->thr->fast_state.IncrementEpoch();
-  // Can't increment epoch w/o writing to the trace as well.
-  TraceAddEvent(args->thr, args->thr->fast_state, EventTypeMop, 0);
-  ReleaseImpl(args->thr, 0, &sync);
-  creation_stack_id = CurrentStackId(args->thr, args->pc);
-}
-
 void ThreadContext::OnReset() {
   CHECK_EQ(sync.size(), 0);
   uptr trace_p = GetThreadTrace(tid);
   ReleaseMemoryPagesToOS(trace_p, trace_p + TraceSize() * sizeof(Event));
   //!!! ReleaseMemoryToOS(GetThreadTraceHeader(tid), sizeof(Trace));
 }
 
-void ThreadContext::OnDetached(void *arg) {
-  ThreadState *thr1 = static_cast<ThreadState*>(arg);
-  sync.Reset(&thr1->proc()->clock_cache);
-}
-
-struct OnStartedArgs {
-  ThreadState *thr;
-  uptr stk_addr;
-  uptr stk_size;
-  uptr tls_addr;
-  uptr tls_size;
-};
-
-void ThreadContext::OnStarted(void *arg) {
-  OnStartedArgs *args = static_cast<OnStartedArgs*>(arg);
-  thr = args->thr;
-  // RoundUp so that one trace part does not contain events
-  // from different threads.
-  epoch0 = RoundUp(epoch1 + 1, kTracePartSize);
-  epoch1 = (u64)-1;
-  new(thr) ThreadState(ctx, tid, unique_id, epoch0, reuse_count,
-      args->stk_addr, args->stk_size, args->tls_addr, args->tls_size);
-#if !SANITIZER_GO
-  thr->shadow_stack = &ThreadTrace(thr->tid)->shadow_stack[0];
-  thr->shadow_stack_pos = thr->shadow_stack;
-  thr->shadow_stack_end = thr->shadow_stack + kShadowStackSize;
-#else
-  // Setup dynamic shadow stack.
-  const int kInitStackSize = 8;
-  thr->shadow_stack = (uptr *)Alloc(kInitStackSize * sizeof(uptr));
-  thr->shadow_stack_pos = thr->shadow_stack;
-  thr->shadow_stack_end = thr->shadow_stack + kInitStackSize;
-#endif
-  if (common_flags()->detect_deadlocks)
-    thr->dd_lt = ctx->dd->CreateLogicalThread(unique_id);
-  thr->fast_state.SetHistorySize(flags()->history_size);
-  // Commit switch to the new part of the trace.
-  // TraceAddEvent will reset stack0/mset0 in the new part for us.
-  TraceAddEvent(thr, thr->fast_state, EventTypeMop, 0);
-
-  thr->fast_synch_epoch = epoch0;
-  AcquireImpl(thr, 0, &sync);
-  sync.Reset(&thr->proc()->clock_cache);
-  thr->is_inited = true;
-  DPrintf("#%d: ThreadStart epoch=%zu stk_addr=%zx stk_size=%zx "
-          "tls_addr=%zx tls_size=%zx\n",
-          tid, (uptr)epoch0, args->stk_addr, args->stk_size,
-          args->tls_addr, args->tls_size);
-}
-
-void ThreadContext::OnFinished() {
-#if SANITIZER_GO
-  Free(thr->shadow_stack);
-  thr->shadow_stack_pos = nullptr;
-  thr->shadow_stack_end = nullptr;
-#endif
-  if (!detached) {
-    thr->fast_state.IncrementEpoch();
-    // Can't increment epoch w/o writing to the trace as well.
-    TraceAddEvent(thr, thr->fast_state, EventTypeMop, 0);
-    ReleaseImpl(thr, 0, &sync);
-  }
-  epoch1 = thr->fast_state.epoch();
-
-  if (common_flags()->detect_deadlocks)
-    ctx->dd->DestroyLogicalThread(thr->dd_lt);
-  thr->clock.ResetCached(&thr->proc()->clock_cache);
-#if !SANITIZER_GO
-  thr->last_sleep_clock.ResetCached(&thr->proc()->clock_cache);
-#endif
-#if !SANITIZER_GO
-  PlatformCleanUpThreadState(thr);
-#endif
-  thr->~ThreadState();
-  thr = 0;
-}
-
 #if !SANITIZER_GO
 struct ThreadLeak {
   ThreadContext *tctx;
   int count;
 };
 
 static void CollectThreadLeaks(ThreadContextBase *tctx_base, void *arg) {
   auto &leaks = *static_cast<Vector<ThreadLeak> *>(arg);

 }
 
 int ThreadCount(ThreadState *thr) {
   uptr result;
   ctx->thread_registry.GetNumberOfThreads(0, 0, &result);
   return (int)result;
 }
 
+struct OnCreatedArgs {
+  ThreadState *thr;
+  uptr pc;
+};
+
 Tid ThreadCreate(ThreadState *thr, uptr pc, uptr uid, bool detached) {
   OnCreatedArgs args = { thr, pc };
   u32 parent_tid = thr ? thr->tid : kInvalidTid;  // No parent for GCD workers.
   Tid tid = ctx->thread_registry.CreateThread(uid, detached, parent_tid, &args);
   DPrintf("#%d: ThreadCreate tid=%d uid=%zu\n", parent_tid, tid, uid);
   return tid;
 }
 
+void ThreadContext::OnCreated(void *arg) {
+  thr = 0;
+  if (tid == kMainTid)
+    return;
+  OnCreatedArgs *args = static_cast<OnCreatedArgs *>(arg);
+  if (!args->thr)  // GCD workers don't have a parent thread.
+    return;
+  args->thr->fast_state.IncrementEpoch();
+  // Can't increment epoch w/o writing to the trace as well.
+  TraceAddEvent(args->thr, args->thr->fast_state, EventTypeMop, 0);
+  ReleaseImpl(args->thr, 0, &sync);
+  creation_stack_id = CurrentStackId(args->thr, args->pc);
+}
+
+struct OnStartedArgs {
+  ThreadState *thr;
+  uptr stk_addr;
+  uptr stk_size;
+  uptr tls_addr;
+  uptr tls_size;
+};
+
 void ThreadStart(ThreadState *thr, Tid tid, tid_t os_id,
                  ThreadType thread_type) {
   uptr stk_addr = 0;
   uptr stk_size = 0;
   uptr tls_addr = 0;
   uptr tls_size = 0;
 #if !SANITIZER_GO
   if (thread_type != ThreadType::Fiber)
#if !SANITIZER_GO
   if (ctx->after_multithreaded_fork) {
     thr->ignore_interceptors++;
     ThreadIgnoreBegin(thr, 0);
     ThreadIgnoreSyncBegin(thr, 0);
   }
 #endif
 }
 
+void ThreadContext::OnStarted(void *arg) {
+  OnStartedArgs *args = static_cast<OnStartedArgs *>(arg);
+  thr = args->thr;
+  // RoundUp so that one trace part does not contain events
+  // from different threads.
+  epoch0 = RoundUp(epoch1 + 1, kTracePartSize);
+  epoch1 = (u64)-1;
+  new (thr)
+      ThreadState(ctx, tid, unique_id, epoch0, reuse_count, args->stk_addr,
+                  args->stk_size, args->tls_addr, args->tls_size);
+#if !SANITIZER_GO
+  thr->shadow_stack = &ThreadTrace(thr->tid)->shadow_stack[0];
+  thr->shadow_stack_pos = thr->shadow_stack;
+  thr->shadow_stack_end = thr->shadow_stack + kShadowStackSize;
+#else
+  // Setup dynamic shadow stack.
+  const int kInitStackSize = 8;
+  thr->shadow_stack = (uptr *)Alloc(kInitStackSize * sizeof(uptr));
+  thr->shadow_stack_pos = thr->shadow_stack;
+  thr->shadow_stack_end = thr->shadow_stack + kInitStackSize;
+#endif
+  if (common_flags()->detect_deadlocks)
+    thr->dd_lt = ctx->dd->CreateLogicalThread(unique_id);
+  thr->fast_state.SetHistorySize(flags()->history_size);
+  // Commit switch to the new part of the trace.
+  // TraceAddEvent will reset stack0/mset0 in the new part for us.
+  TraceAddEvent(thr, thr->fast_state, EventTypeMop, 0);
+
+  thr->fast_synch_epoch = epoch0;
+  AcquireImpl(thr, 0, &sync);
+  sync.Reset(&thr->proc()->clock_cache);
+  thr->is_inited = true;
+  DPrintf(
+      "#%d: ThreadStart epoch=%zu stk_addr=%zx stk_size=%zx "
+      "tls_addr=%zx tls_size=%zx\n",
+      tid, (uptr)epoch0, args->stk_addr, args->stk_size, args->tls_addr,
+      args->tls_size);
+}
+
 void ThreadFinish(ThreadState *thr) {
   ThreadCheckIgnore(thr);
   if (thr->stk_addr && thr->stk_size)
     DontNeedShadowFor(thr->stk_addr, thr->stk_size);
   if (thr->tls_addr && thr->tls_size)
     DontNeedShadowFor(thr->tls_addr, thr->tls_size);
   thr->is_dead = true;
   ctx->thread_registry.FinishThread(thr->tid);
 }
 
+void ThreadContext::OnFinished() {
+#if SANITIZER_GO
+  Free(thr->shadow_stack);
+  thr->shadow_stack_pos = nullptr;
+  thr->shadow_stack_end = nullptr;
+#endif
+  if (!detached) {
+    thr->fast_state.IncrementEpoch();
+    // Can't increment epoch w/o writing to the trace as well.
+    TraceAddEvent(thr, thr->fast_state, EventTypeMop, 0);
+    ReleaseImpl(thr, 0, &sync);
+  }
+  epoch1 = thr->fast_state.epoch();
+
+  if (common_flags()->detect_deadlocks)
+    ctx->dd->DestroyLogicalThread(thr->dd_lt);
+  thr->clock.ResetCached(&thr->proc()->clock_cache);
+#if !SANITIZER_GO
+  thr->last_sleep_clock.ResetCached(&thr->proc()->clock_cache);
+#endif
+#if !SANITIZER_GO
+  PlatformCleanUpThreadState(thr);
+#endif
+  thr->~ThreadState();
+  thr = 0;
+}
+
 struct ConsumeThreadContext {
   uptr uid;
   ThreadContextBase *tctx;
 };
 
 static bool ConsumeThreadByUid(ThreadContextBase *tctx, void *arg) {
   ConsumeThreadContext *findCtx = (ConsumeThreadContext *)arg;
   if (tctx->user_id == findCtx->uid && tctx->status != ThreadStatusInvalid) {

 
 void ThreadJoin(ThreadState *thr, uptr pc, Tid tid) {
   CHECK_GT(tid, 0);
   CHECK_LT(tid, kMaxTid);
   DPrintf("#%d: ThreadJoin tid=%d\n", thr->tid, tid);
   ctx->thread_registry.JoinThread(tid, thr);
 }
 
+void ThreadContext::OnJoined(void *arg) {
+  ThreadState *caller_thr = static_cast<ThreadState *>(arg);
+  AcquireImpl(caller_thr, 0, &sync);
+  sync.Reset(&caller_thr->proc()->clock_cache);
+}
+
+void ThreadContext::OnDead() { CHECK_EQ(sync.size(), 0); }
+
 void ThreadDetach(ThreadState *thr, uptr pc, Tid tid) {
   CHECK_GT(tid, 0);
   CHECK_LT(tid, kMaxTid);
   ctx->thread_registry.DetachThread(tid, thr);
 }
 
+void ThreadContext::OnDetached(void *arg) {
+  ThreadState *thr1 = static_cast<ThreadState *>(arg);
+  sync.Reset(&thr1->proc()->clock_cache);
+}
+
 void ThreadNotJoined(ThreadState *thr, uptr pc, Tid tid, uptr uid) {
   CHECK_GT(tid, 0);
   CHECK_LT(tid, kMaxTid);
   ctx->thread_registry.SetThreadUserId(tid, uid);
 }
 
 void ThreadSetName(ThreadState *thr, const char *name) {
   ctx->thread_registry.SetThreadName(thr->tid, name);