[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)) {
+    Report("ERROR: finishing a fiber switch that has not started\n");
+    Die();
+  }
+
+  if (bottom_old)
+    *bottom_old = stack_bottom_;
+  if (size_old)
+    *size_old = stack_top_ - stack_bottom_;
+  stack_bottom_ = next_stack_bottom_;
+  stack_top_ = next_stack_top_;
+  atomic_store(&stack_switching_, 0, memory_order_release);
+  next_stack_top_ = 0;
+  next_stack_bottom_ = 0;
+}
+
+inline Thread::StackBounds Thread::GetStackBounds() const {
+  if (!atomic_load(&stack_switching_, memory_order_acquire)) {
+    // Make sure the stack bounds are fully initialized.
+    if (stack_bottom_ >= stack_top_)
+      return {0, 0};
+    return {stack_bottom_, stack_top_};
+  }
+  char local;
+  const uptr cur_stack = (uptr)&local;
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Tomahawkd wrote:

Fixed

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