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

[Brian Cain via cfe-commits]

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@@ -0,0 +1,62 @@
+//===-- xray_init.cpp -------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of XRay, a dynamic runtime instrumentation system.
+//
+// XRay initialisation logic for DSOs.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_atomic.h"
+#include "xray_defs.h"
+#include "xray_flags.h"
+#include "xray_interface_internal.h"
+
+using namespace __sanitizer;
+
+extern "C" {
+extern const XRaySledEntry __start_xray_instr_map[] __attribute__((weak))
+__attribute__((visibility("hidden")));
+extern const XRaySledEntry __stop_xray_instr_map[] __attribute__((weak))
+__attribute__((visibility("hidden")));
+extern const XRayFunctionSledIndex __start_xray_fn_idx[] __attribute__((weak))
+__attribute__((visibility("hidden")));
+extern const XRayFunctionSledIndex __stop_xray_fn_idx[] __attribute__((weak))
+__attribute__((visibility("hidden")));
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androm3da wrote:

How would this symbol resolution behave in a case where the main executable was not built with `-fxray-enable` and only the shared objects were?  If this case is unsupported, can we detect it and log a message or abort()/terminate?

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