From 658475897b14781070549f72483fd283e3fe50aa Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka@google.com>
Date: Fri, 11 Sep 2020 13:45:07 -0700
Subject: [PATCH] [NFC][Asan] Early return from GetBlockBegin

---
 .../lib/sanitizer_common/sanitizer_allocator_primary64.h        | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary64.h b/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary64.h
index 774c09e42495..0a18b0c58ef7 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary64.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary64.h
@@ -186,13 +186,13 @@ class SizeClassAllocator64 {
 
   void *GetBlockBegin(const void *p) {
     uptr class_id = GetSizeClass(p);
+    if (class_id >= kNumClasses) return nullptr;
     uptr size = ClassIdToSize(class_id);
     if (!size) return nullptr;
     uptr chunk_idx = GetChunkIdx((uptr)p, size);
     uptr reg_beg = GetRegionBegin(p);
     uptr beg = chunk_idx * size;
     uptr next_beg = beg + size;
-    if (class_id >= kNumClasses) return nullptr;
     const RegionInfo *region = AddressSpaceView::Load(GetRegionInfo(class_id));
     if (region->mapped_user >= next_beg)
       return reinterpret_cast<void*>(reg_beg + beg);