[compiler-rt] b5bc56d - [NFC][Asan] Fit ChunkHeader into redzone

[Vitaly Buka via llvm-commits]

Author: Vitaly Buka
Date: 2020-09-09T03:29:51-07:00
New Revision: b5bc56da8aa23dc57db9d286b0591dbcf9b1bdd3

URL: https://github.com/llvm/llvm-project/commit/b5bc56da8aa23dc57db9d286b0591dbcf9b1bdd3
DIFF: https://github.com/llvm/llvm-project/commit/b5bc56da8aa23dc57db9d286b0591dbcf9b1bdd3.diff

LOG: [NFC][Asan] Fit ChunkHeader into redzone

In code as-is min redzone and ChunkHeader are 16 byte.
This patch just makes sure that redzone is calculated correctly if we
extend ChunkHeader.

Added: 
    

Modified: 
    compiler-rt/lib/asan/asan_allocator.cpp

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/asan/asan_allocator.cpp b/compiler-rt/lib/asan/asan_allocator.cpp
index a15c569b42ba..64796f752671 100644
--- a/compiler-rt/lib/asan/asan_allocator.cpp
+++ b/compiler-rt/lib/asan/asan_allocator.cpp
@@ -354,17 +354,18 @@ struct Allocator {
 
   // -------------------- Helper methods. -------------------------
   uptr ComputeRZLog(uptr user_requested_size) {
-    u32 rz_log =
-      user_requested_size <= 64        - 16   ? 0 :
-      user_requested_size <= 128       - 32   ? 1 :
-      user_requested_size <= 512       - 64   ? 2 :
-      user_requested_size <= 4096      - 128  ? 3 :
-      user_requested_size <= (1 << 14) - 256  ? 4 :
-      user_requested_size <= (1 << 15) - 512  ? 5 :
-      user_requested_size <= (1 << 16) - 1024 ? 6 : 7;
-    u32 min_rz = atomic_load(&min_redzone, memory_order_acquire);
-    u32 max_rz = atomic_load(&max_redzone, memory_order_acquire);
-    return Min(Max(rz_log, RZSize2Log(min_rz)), RZSize2Log(max_rz));
+    u32 rz_log = user_requested_size <= 64 - 16            ? 0
+                 : user_requested_size <= 128 - 32         ? 1
+                 : user_requested_size <= 512 - 64         ? 2
+                 : user_requested_size <= 4096 - 128       ? 3
+                 : user_requested_size <= (1 << 14) - 256  ? 4
+                 : user_requested_size <= (1 << 15) - 512  ? 5
+                 : user_requested_size <= (1 << 16) - 1024 ? 6
+                                                           : 7;
+    u32 hdr_log = RZSize2Log(RoundUpToPowerOfTwo(sizeof(ChunkHeader)));
+    u32 min_log = RZSize2Log(atomic_load(&min_redzone, memory_order_acquire));
+    u32 max_log = RZSize2Log(atomic_load(&max_redzone, memory_order_acquire));
+    return Min(Max(rz_log, Max(min_log, hdr_log)), Max(max_log, hdr_log));
   }
 
   static uptr ComputeUserRequestedAlignmentLog(uptr user_requested_alignment) {