1 files changed, 21 insertions, 0 deletions

diff --git a/compiler-rt/lib/xray/xray_buffer_queue.h b/compiler-rt/lib/xray/xray_buffer_queue.h
index c1fa9fab768..cbd42835f8a 100644
--- a/compiler-rt/lib/xray/xray_buffer_queue.h
+++ b/compiler-rt/lib/xray/xray_buffer_queue.h
@@ -33,6 +33,7 @@ class BufferQueue {
 public:
   struct Buffer {
     atomic_uint64_t Extents{0};
+    uint64_t Generation{0};
     void *Data = nullptr;
     size_t Size = 0;
   };
@@ -130,6 +131,10 @@ private:
   // Count of buffers that have been handed out through 'getBuffer'.
   size_t LiveBuffers;
 
+  // We use a generation number to identify buffers and which generation they're
+  // associated with.
+  atomic_uint64_t Generation;
+
 public:
   enum class ErrorCode : unsigned {
     Ok,
@@ -137,6 +142,7 @@ public:
     QueueFinalizing,
     UnrecognizedBuffer,
     AlreadyFinalized,
+    AlreadyInitialized,
   };
 
   static const char *getErrorString(ErrorCode E) {
@@ -151,6 +157,8 @@ public:
       return "buffer being returned not owned by buffer queue";
     case ErrorCode::AlreadyFinalized:
       return "queue already finalized";
+    case ErrorCode::AlreadyInitialized:
+      return "queue already initialized";
     }
     return "unknown error";
   }
@@ -181,10 +189,23 @@ public:
   ///     the buffer being released.
   ErrorCode releaseBuffer(Buffer &Buf);
 
+  /// Initializes the buffer queue, starting a new generation. We can re-set the
+  /// size of buffers with |BS| along with the buffer count with |BC|.
+  ///
+  /// Returns:
+  ///   - ErrorCode::Ok when we successfully initialize the buffer. This
+  ///   requires that the buffer queue is previously finalized.
+  ///   - ErrorCode::AlreadyInitialized when the buffer queue is not finalized.
+  ErrorCode init(size_t BS, size_t BC);
+
   bool finalizing() const {
     return atomic_load(&Finalizing, memory_order_acquire);
   }
 
+  uint64_t generation() const {
+    return atomic_load(&Generation, memory_order_acquire);
+  }
+
   /// Returns the configured size of the buffers in the buffer queue.
   size_t ConfiguredBufferSize() const { return BufferSize; }