[compiler-rt] [scudo] Only init RingBuffer when needed. (PR #85994)

[via llvm-commits]

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@@ -867,29 +867,83 @@ SCUDO_TYPED_TEST(ScudoCombinedTest, ReallocateInPlaceStress) {
   }
 }
 
+SCUDO_TYPED_TEST(ScudoCombinedTest, RingBufferDefaultDisabled) {
+  // The RingBuffer is not initialized until tracking is enabled for the
+  // first time.
+  auto *Allocator = this->Allocator.get();
+  ASSERT_EQ(0u, Allocator->getRingBufferSize());
+  ASSERT_EQ(nullptr, Allocator->getRingBufferAddress());
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ChiaHungDuan wrote:

I think we may want to use EXPECT_* instead of ASSERT_* here and below given that it's not a fatal failure. (I know you're following the styles, or we can fix them in another CL)

https://github.com/llvm/llvm-project/pull/85994