[XRay][compiler-rt] Support patching/unpatching specific functions

Summary:
This change allows us to patch/unpatch specific functions using the
function ID. This is useful in cases where implementations might want to
do coverage-style, or more fine-grained control of which functions to
patch or un-patch at runtime.

Depends on D32693.

Reviewers: dblaikie, echristo, kpw

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D32695

llvm-svn: 302112

1 files changed, 8 insertions, 0 deletions

diff --git a/compiler-rt/include/xray/xray_interface.h b/compiler-rt/include/xray/xray_interface.h
index 52a7e1d9e94..e2d0a89d67b 100644
--- a/compiler-rt/include/xray/xray_interface.h
+++ b/compiler-rt/include/xray/xray_interface.h
@@ -67,6 +67,14 @@ extern XRayPatchingStatus __xray_patch();
 // result values.
 extern XRayPatchingStatus __xray_unpatch();
 
+// This patches a specific function id. See XRayPatchingStatus for possible
+// result values.
+extern XRayPatchingStatus __xray_patch_function(int32_t FuncId);
+
+// This unpatches a specific function id. See XRayPatchingStatus for possible
+// result values.
+extern XRayPatchingStatus __xray_unpatch_function(int32_t FuncId);
+
 // Use XRay to log the first argument of each (instrumented) function call.
 // When this function exits, all threads will have observed the effect and
 // start logging their subsequent affected function calls (if patched).