From 9b1dbf02c9adffedc28c56284967ab87941abb53 Mon Sep 17 00:00:00 2001
From: Dean Michael Berris <dberris@google.com>
Date: Wed, 20 Jul 2016 14:14:50 +0000
Subject: [compiler-rt] [XRay] Basic initialization and flag definition for
 XRay runtime

Summary:
This patch implements the initialisation and patching routines for the XRay runtime, along with the necessary trampolines for function entry/exit handling. For now we only define the basic hooks for allowing an implementation to define a handler that gets run on function entry/exit. We expose a minimal API for controlling the behaviour of the runtime (patching, cleanup, and setting the handler to invoke when instrumenting).

Depends on D19904

Reviewers: echristo, kcc, rnk

Subscribers: rnk, mehdi_amini, llvm-commits

Differential Revision: https://reviews.llvm.org/D21612

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@276117 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/xray/xray_interface.h | 66 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 include/xray/xray_interface.h

(limited to 'include/xray')

diff --git a/include/xray/xray_interface.h b/include/xray/xray_interface.h
new file mode 100644
index 000000000..b8a0a6192
--- /dev/null
+++ b/include/xray/xray_interface.h
@@ -0,0 +1,66 @@
+//===-- xray_interface.h ----------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of XRay, a dynamic runtime instrumentation system.
+//
+// APIs for controlling XRay functionality explicitly.
+//===----------------------------------------------------------------------===//
+#ifndef XRAY_XRAY_INTERFACE_H
+#define XRAY_XRAY_INTERFACE_H
+
+#include <cstdint>
+
+extern "C" {
+
+enum XRayEntryType { ENTRY = 0, EXIT = 1 };
+
+// Provide a function to invoke for when instrumentation points are hit. This is
+// a user-visible control surface that overrides the default implementation. The
+// function provided should take the following arguments:
+//
+//   - function id: an identifier that indicates the id of a function; this id
+//                  is generated by xray; the mapping between the function id
+//                  and the actual function pointer is available through
+//                  __xray_table.
+//   - entry type: identifies what kind of instrumentation point was encountered
+//                 (function entry, function exit, etc.). See the enum
+//                 XRayEntryType for more details.
+//
+// Returns 1 on success, 0 on error.
+extern int __xray_set_handler(void (*entry)(int32_t, XRayEntryType));
+
+// This removes whatever the currently provided handler is. Returns 1 on
+// success, 0 on error.
+extern int __xray_remove_handler();
+
+enum XRayPatchingStatus {
+  NOT_INITIALIZED = 0,
+  NOTIFIED = 1,
+  ONGOING = 2,
+  FAILED = 3
+};
+
+// This tells XRay to patch the instrumentation points. This is an asynchronous
+// process, and returns the following status in specific cases:
+//
+//   - 0 : XRay is not initialized.
+//   - 1 : We've done the notification.
+//   - 2 : Patching / un-patching is on-going.
+extern XRayPatchingStatus __xray_patch();
+
+// Reverses the effect of __xray_patch(). This is an asynchronous process, and
+// returns the following status in specific cases.
+//
+//   - 0 : XRay is not initialized.
+//   - 1 : We've done the notification.
+//   - 2 : Patching / un-patching is on-going.
+extern int __xray_unpatch();
+}
+
+#endif
-- 
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