[compiler-rt] [NFC] [scudo] move static_asserts closer to what they relate to (PR #84257)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: Florian Mayer (fmayer)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/84257.diff


2 Files Affected:

- (modified) compiler-rt/lib/scudo/standalone/combined.h (+5-11) 
- (modified) compiler-rt/lib/scudo/standalone/stack_depot.h (+4) 


``````````diff
diff --git a/compiler-rt/lib/scudo/standalone/combined.h b/compiler-rt/lib/scudo/standalone/combined.h
index fa6077384d9826..c0b2ab63327fda 100644
--- a/compiler-rt/lib/scudo/standalone/combined.h
+++ b/compiler-rt/lib/scudo/standalone/combined.h
@@ -1553,16 +1553,6 @@ class Allocator {
     constexpr u32 kFramesPerStack = 16;
     static_assert(isPowerOfTwo(kFramesPerStack));
 
-    // We need StackDepot to be aligned to 8-bytes so the ring we store after
-    // is correctly assigned.
-    static_assert(sizeof(StackDepot) % alignof(atomic_u64) == 0);
-
-    // Make sure the maximum sized StackDepot fits withint a uintptr_t to
-    // simplify the overflow checking.
-    static_assert(sizeof(StackDepot) + UINT32_MAX * sizeof(atomic_u64) *
-                                           UINT32_MAX * sizeof(atomic_u32) <
-                  UINTPTR_MAX);
-
     if (AllocationRingBufferSize > kMaxU32Pow2 / kStacksPerRingBufferEntry)
       return;
     u32 TabSize = static_cast<u32>(roundUpPowerOfTwo(kStacksPerRingBufferEntry *
@@ -1570,8 +1560,12 @@ class Allocator {
     if (TabSize > UINT32_MAX / kFramesPerStack)
       return;
     u32 RingSize = static_cast<u32>(TabSize * kFramesPerStack);
-    DCHECK(isPowerOfTwo(RingSize));
 
+    // Make sure the maximum sized StackDepot fits withint a uintptr_t to
+    // prove we don't need overflow checking for StackDepotSize.
+    static_assert(sizeof(StackDepot) + UINT32_MAX * sizeof(atomic_u64) *
+                                           UINT32_MAX * sizeof(atomic_u32) <
+                  UINTPTR_MAX);
     uptr StackDepotSize = sizeof(StackDepot) + sizeof(atomic_u64) * RingSize +
                           sizeof(atomic_u32) * TabSize;
     MemMapT DepotMap;
diff --git a/compiler-rt/lib/scudo/standalone/stack_depot.h b/compiler-rt/lib/scudo/standalone/stack_depot.h
index 620137e44f3723..cf3cabf7085b60 100644
--- a/compiler-rt/lib/scudo/standalone/stack_depot.h
+++ b/compiler-rt/lib/scudo/standalone/stack_depot.h
@@ -199,6 +199,10 @@ class alignas(atomic_u64) StackDepot {
   void enable() NO_THREAD_SAFETY_ANALYSIS { RingEndMu.unlock(); }
 };
 
+// We need StackDepot to be aligned to 8-bytes so the ring we store after
+// is correctly assigned.
+static_assert(sizeof(StackDepot) % alignof(atomic_u64) == 0);
+
 } // namespace scudo
 
 #endif // SCUDO_STACK_DEPOT_H_

``````````

</details>


https://github.com/llvm/llvm-project/pull/84257