[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, 7 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 57b1c4b..5367c2a 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -468,7 +468,10 @@ bool CodeGenFunction::ShouldXRayInstrumentFunction() const {
 /// AlwaysEmitXRayCustomEvents - Return true if we should emit IR for calls to
 /// the __xray_customevent(...) builin calls, when doing XRay instrumentation.
 bool CodeGenFunction::AlwaysEmitXRayCustomEvents() const {
-  return CGM.getCodeGenOpts().XRayAlwaysEmitCustomEvents;
+  return CGM.getCodeGenOpts().XRayInstrumentFunctions &&
+         (CGM.getCodeGenOpts().XRayAlwaysEmitCustomEvents ||
+          CGM.getCodeGenOpts().XRayInstrumentationBundle.Mask ==
+              XRayInstrKind::Custom);
 }
 
 llvm::Constant *
@@ -900,7 +903,9 @@ void CodeGenFunction::StartFunction(GlobalDecl GD,
   }
 
   // Apply xray attributes to the function (as a string, for now)
-  bool InstrumentXray = ShouldXRayInstrumentFunction();
+  bool InstrumentXray = ShouldXRayInstrumentFunction() &&
+                        CGM.getCodeGenOpts().XRayInstrumentationBundle.has(
+                            XRayInstrKind::Function);
   if (D && InstrumentXray) {
     if (const auto *XRayAttr = D->getAttr<XRayInstrumentAttr>()) {
       if (XRayAttr->alwaysXRayInstrument())