[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, 9 insertions, 3 deletions

diff --git a/lib/xray/xray_arm.cc b/lib/xray/xray_arm.cc
index 26d673ec2..94e1c2638 100644
--- a/lib/xray/xray_arm.cc
+++ b/lib/xray/xray_arm.cc
@@ -18,7 +18,7 @@
 #include <atomic>
 #include <cassert>
 
-extern "C" void __clear_cache(void* start, void* end);
+extern "C" void __clear_cache(void *start, void *end);
 
 namespace __xray {
 
@@ -122,8 +122,8 @@ inline static bool patchSled(const bool Enable, const uint32_t FuncId,
         reinterpret_cast<std::atomic<uint32_t> *>(FirstAddress),
         uint32_t(PatchOpcodes::PO_B20), std::memory_order_release);
   }
-  __clear_cache(reinterpret_cast<char*>(FirstAddress),
-      reinterpret_cast<char*>(CurAddress));
+  __clear_cache(reinterpret_cast<char *>(FirstAddress),
+                reinterpret_cast<char *>(CurAddress));
   return true;
 }
 
@@ -143,6 +143,12 @@ bool patchFunctionTailExit(const bool Enable, const uint32_t FuncId,
   return patchSled(Enable, FuncId, Sled, __xray_FunctionTailExit);
 }
 
+bool patchCustomEvent(const bool Enable, const uint32_t FuncId,
+                      const XRaySled &Sled)
+    XRAY_NEVER_INSTRUMENT { // FIXME: Implement in arm?
+  return false;
+}
+
 // FIXME: Maybe implement this better?
 bool probeRequiredCPUFeatures() XRAY_NEVER_INSTRUMENT { return true; }