[XRay][clang] Add flag to choose instrumentation bundles

Summary:
This change addresses http://llvm.org/PR36926 by allowing users to pick
which instrumentation bundles to use, when instrumenting with XRay. In
particular, the flag `-fxray-instrumentation-bundle=` has four valid
values:

- `all`: the default, emits all instrumentation kinds
- `none`: equivalent to -fnoxray-instrument
- `function`: emits the entry/exit instrumentation
- `custom`: emits the custom event instrumentation

These can be combined either as comma-separated values, or as
repeated flag values.

Reviewers: echristo, kpw, eizan, pelikan

Reviewed By: pelikan

Subscribers: mgorny, cfe-commits

Differential Revision: https://reviews.llvm.org/D44970

llvm-svn: 329985

1 files changed, 5 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 73b95d981f4..4baa5aff72e 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -3341,6 +3341,11 @@ RValue CodeGenFunction::EmitBuiltinExpr(const FunctionDecl *FD,
   case Builtin::BI__xray_customevent: {
     if (!ShouldXRayInstrumentFunction())
       return RValue::getIgnored();
+
+    if (!CGM.getCodeGenOpts().XRayInstrumentationBundle.has(
+            XRayInstrKind::Custom))
+      return RValue::getIgnored();
+
     if (const auto *XRayAttr = CurFuncDecl->getAttr<XRayInstrumentAttr>())
       if (XRayAttr->neverXRayInstrument() && !AlwaysEmitXRayCustomEvents())
         return RValue::getIgnored();