[clang] [compiler-rt] [XRay] Add support for instrumentation of DSOs on x86_64 (PR #90959)

[Jan Patrick Lehr via cfe-commits]

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@@ -80,29 +140,14 @@ void __xray_init() XRAY_NEVER_INSTRUMENT {
     return;
   }
 
-  {
-    SpinMutexLock Guard(&XRayInstrMapMutex);
-    XRayInstrMap.Sleds = __start_xray_instr_map;
-    XRayInstrMap.Entries = __stop_xray_instr_map - __start_xray_instr_map;
-    if (__start_xray_fn_idx != nullptr) {
-      XRayInstrMap.SledsIndex = __start_xray_fn_idx;
-      XRayInstrMap.Functions = __stop_xray_fn_idx - __start_xray_fn_idx;
-    } else {
-      size_t CountFunctions = 0;
-      uint64_t LastFnAddr = 0;
-
-      for (std::size_t I = 0; I < XRayInstrMap.Entries; I++) {
-        const auto &Sled = XRayInstrMap.Sleds[I];
-        const auto Function = Sled.function();
-        if (Function != LastFnAddr) {
-          CountFunctions++;
-          LastFnAddr = Function;
-        }
-      }
+  atomic_store(&XRayNumObjects, 0, memory_order_release);
+
+  // Pre-allocation takes up approx. 5kB for XRayMaxObjects=64.
+  XRayInstrMaps = allocateBuffer<XRaySledMap>(XRayMaxObjects);
+
+  __xray_register_sleds(__start_xray_instr_map, __stop_xray_instr_map,
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jplehr wrote:

Why is the return value not checked?

https://github.com/llvm/llvm-project/pull/90959