[XRay][compiler-rt] Runtime changes to support custom event logging

Summary:
This change implements support for the custom event logging sleds and
intrinsics at runtime. For now it only supports handling the sleds in
x86_64, with the implementations for other architectures stubbed out to
do nothing.

NOTE: Work in progress, uploaded for exposition/exploration purposes.

Depends on D27503, D30018, and D33032.

Reviewers: echristo, javed.absar, timshen

Subscribers: mehdi_amini, nemanjai, llvm-commits

Differential Revision: https://reviews.llvm.org/D30630

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@302857 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 38 insertions, 0 deletions

diff --git a/test/xray/TestCases/Linux/custom-event-logging.cc b/test/xray/TestCases/Linux/custom-event-logging.cc
new file mode 100644
index 000000000..29d177b9e
--- /dev/null
+++ b/test/xray/TestCases/Linux/custom-event-logging.cc
@@ -0,0 +1,38 @@
+// Use the clang feature for custom xray event logging.
+//
+// RUN: %clangxx_xray -std=c++11 %s -o %t
+// RUN: XRAY_OPTIONS="patch_premain=false verbosity=1 xray_naive_log=false xray_logfile_base=custom-event-logging.xray-" %run %t 2>&1 | FileCheck %s
+//
+#include <cstdio>
+#include "xray/xray_interface.h"
+
+[[clang::xray_always_instrument]] void foo() {
+  static constexpr char CustomLogged[] = "hello custom logging!";
+  printf("before calling the custom logging...\n");
+  __xray_customevent(CustomLogged, sizeof(CustomLogged));
+  printf("after calling the custom logging...\n");
+}
+
+void myprinter(void* ptr, size_t size) {
+  printf("%.*s\n", static_cast<int>(size), static_cast<const char*>(ptr));
+}
+
+int main() {
+  foo();
+  // CHECK: before calling the custom logging...
+  // CHECK-NEXT: after calling the custom logging...
+  printf("setting up custom event handler...\n");
+  // CHECK-NEXT: setting up custom event handler...
+  __xray_set_customevent_handler(myprinter);
+  __xray_patch();
+  // CHECK-NEXT: before calling the custom logging...
+  foo();
+  // CHECK-NEXT: hello custom logging!
+  // CHECK-NEXT: after calling the custom logging...
+  printf("removing custom event handler...\n");
+  // CHECK-NEXT: removing custom event handler...
+  __xray_set_customevent_handler(nullptr);
+  foo();
+  // CHECK-NEXT: before calling the custom logging...
+  // CHECK-NEXT: after calling the custom logging...
+}