[XRay][clang] Emit "never-instrument" attribute
Summary:
Before this change, we only emit the XRay attributes in LLVM IR when the
-fxray-instrument flag is provided. This may cause issues with thinlto
when the final binary is being built/linked with -fxray-instrument, and
the constitutent LLVM IR gets re-lowered with xray instrumentation.
With this change, we can honour the "never-instrument "attributes
provided in the source code and preserve those in the IR. This way, even
in thinlto builds, we retain the attributes which say whether functions
should never be XRay instrumented.
This change addresses llvm.org/PR38922.
Reviewers: mboerger, eizan
Subscribers: mehdi_amini, dexonsmith, cfe-commits, llvm-commits
Differential Revision: https://reviews.llvm.org/D52015
llvm-svn: 342200
diff --git a/clang/test/CodeGen/xray-attributes-noxray-supported.cpp b/clang/test/CodeGen/xray-attributes-noxray-supported.cpp
new file mode 100644
index 0000000..f9c8a2e
--- /dev/null
+++ b/clang/test/CodeGen/xray-attributes-noxray-supported.cpp
@@ -0,0 +1,29 @@
+// We want to ensure that the "never instrument" attributes show up even if we
+// explicitly turn off XRay instrumentation.
+//
+// RUN: %clang_cc1 %s -fno-xray-instrument -std=c++11 -x c++ -emit-llvm -o - \
+// RUN: -triple x86_64-unknown-linux-gnu | FileCheck %s
+// RUN: %clang_cc1 %s -fno-xray-instrument -std=c++11 -x c++ -emit-llvm -o - \
+// RUN: -triple arm-unknown-linux-gnu -target-abi apcs-gnu | FileCheck %s
+// RUN: %clang_cc1 %s -fno-xray-instrument -std=c++11 -x c++ -emit-llvm -o - \
+// RUN: -triple mips-unknown-linux-gnu | FileCheck %s
+// RUN: %clang_cc1 %s -fno-xray-instrument -std=c++11 -x c++ -emit-llvm -o - \
+// RUN: -triple mipsel-unknown-linux-gnu | FileCheck %s
+// RUN: %clang_cc1 %s -fno-xray-instrument -std=c++11 -x c++ -emit-llvm -o - \
+// RUN: -triple mips64-unknown-linux-gnu | FileCheck %s
+// RUN: %clang_cc1 %s -fno-xray-instrument -std=c++11 -x c++ -emit-llvm -o - \
+// RUN: -triple mips64el-unknown-linux-gnu | FileCheck %s
+// RUN: %clang_cc1 %s -fno-xray-instrument -std=c++11 -x c++ -emit-llvm -o - \
+// RUN: -triple powerpc64le-unknown-linux-gnu | FileCheck %s
+
+[[clang::xray_always_instrument]] void foo() {
+// CHECK: define void @_Z3foov() #0
+}
+
+[[clang::xray_never_instrument]] void bar() {
+// CHECK: define void @_Z3barv() #1
+}
+
+// CHECK-NOT: #0 = {{.*}}"function-instrument"="xray-always"
+// CHECK: #1 = {{.*}}"function-instrument"="xray-never"
+