[asan] Optimize Quarantine of secondary allocations

[vitalybuka]

Summary

For the secondary allocation we don't need poison and fill memory if we
skip quarantine, and we don't need to poison after quarantine. In both
cases the secondary allocator will unmap memory and unpoison the shadow
from get_allocator().Deallocate().

Depends on D153496.

compiler-rt/lib/asan/asan_allocator.cpp

void PreQuarantine(AsanChunk *m) const {
     FillChunk(m);
     // Poison the region.
     PoisonShadow(m->Beg(), RoundUpTo(m->UsedSize(), ASAN_SHADOW_GRANULARITY),
                  kAsanHeapFreeMagic);
   }
 
   void Recycle(AsanChunk *m) const {
     void *p = get_allocator().GetBlockBegin(m);
+
+    // The secondary will immediately unpoison and unmap the memory, so this
+    // branch is unnecessary.
+    if (get_allocator().FromPrimary(p)) {
       if (p != m) {
         // Clear the magic value, as allocator internals may overwrite the
         // contents of deallocated chunk, confusing GetAsanChunk lookup.
         reinterpret_cast<LargeChunkHeader *>(p)->Set(nullptr);
       }
 
       u8 old_chunk_state = CHUNK_QUARANTINE;
       if (!atomic_compare_exchange_strong(&m->chunk_state, &old_chunk_state,
-                                        CHUNK_INVALID, memory_order_acquire)) {
+                                          CHUNK_INVALID,
+                                          memory_order_acquire)) {
         CHECK_EQ(old_chunk_state, CHUNK_QUARANTINE);
       }
 
       PoisonShadow(m->Beg(), RoundUpTo(m->UsedSize(), ASAN_SHADOW_GRANULARITY),
                    kAsanHeapLeftRedzoneMagic);
+    }
 
     // Statistics.
     AsanStats &thread_stats = GetCurrentThreadStats();
     thread_stats.real_frees++;
     thread_stats.really_freed += m->UsedSize();
 
     get_allocator().Deallocate(cache_, p);
   }
 
   void RecyclePassThrough(AsanChunk *m) const {
-    // TODO: We don't need all these here.
-    PreQuarantine(m);
+    // Recycle for the secondary will immediately unpoison and unmap the
+    // memory, so quarantine preparation is unnecessary.
+    if (get_allocator().FromPrimary(m)) {
+      // The primary allocation may need pattern fill if enabled.
+      FillChunk(m);
+    }
     Recycle(m);
   }
 
   void *Allocate(uptr size) const {
     void *res = get_allocator().Allocate(cache_, size, 1);
     // TODO(alekseys): Consider making quarantine OOM-friendly.
     if (UNLIKELY(!res))
       ReportOutOfMemory(size, stack_);