[compiler-rt] [compiler-rt][hwasan] Add fiber switch for HwASan (PR #153822)

[via llvm-commits]

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@@ -119,6 +119,60 @@ void Thread::Destroy() {
   *GetCurrentThreadLongPtr() = 0;
 }
 
+void Thread::StartSwitchFiber(uptr bottom, uptr size) {
+  if (atomic_load(&stack_switching_, memory_order_relaxed)) {
+    Report("ERROR: starting fiber switch while in fiber switch\n");
+    Die();
+  }
+
+  next_stack_bottom_ = bottom;
+  next_stack_top_ = bottom + size;
+  atomic_store(&stack_switching_, 1, memory_order_release);
+}
+
+void Thread::FinishSwitchFiber(uptr *bottom_old, uptr *size_old) {
+  if (!atomic_load(&stack_switching_, memory_order_relaxed)) {
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Tomahawkd wrote:

Fixed both `Thread::StartSwitchFiber` and `Thread::FinishSwitchFiber`

https://github.com/llvm/llvm-project/pull/153822