[XRay][Driver] Do not link in XRay runtime in shared libs

deanberris · deanberris · commit b013dc4b0569 · 2017-09-25T23:40:33.000Z
Summary: This change ensures that we don't link in the XRay runtime when building shared libraries with clang. This doesn't prevent us from building shared libraris tht have XRay instrumentation sleds, but it does prevent us from linking in the static XRay runtime into a shared library. The XRay runtime currently doesn't support dynamic registration of instrumentation sleds in shared objects, which we'll start enabling in the future. That work has to happen in the back-end and in the runtime. Reviewers: rnk, pelikan Subscribers: cfe-commits Differential Revision: https://reviews.llvm.org/D38226 llvm-svn: 314177
diff --git a/clang/lib/Driver/ToolChains/Gnu.cpp b/clang/lib/Driver/ToolChains/Gnu.cpp
@@ -206,13 +206,18 @@ void tools::gcc::Linker::RenderExtraToolArgs(const JobAction &JA,
 
 static bool addXRayRuntime(const ToolChain &TC, const ArgList &Args,
                            ArgStringList &CmdArgs) {
+  // Do not add the XRay runtime to shared libraries.
+  if (Args.hasArg(options::OPT_shared))
+    return false;
+
   if (Args.hasFlag(options::OPT_fxray_instrument,
                    options::OPT_fnoxray_instrument, false)) {
     CmdArgs.push_back("-whole-archive");
     CmdArgs.push_back(TC.getCompilerRTArgString(Args, "xray", false));
     CmdArgs.push_back("-no-whole-archive");
     return true;
   }
+
   return false;
 }
 
diff --git a/clang/test/Driver/XRay/xray-shared-noxray.cpp b/clang/test/Driver/XRay/xray-shared-noxray.cpp
@@ -0,0 +1,14 @@
+// RUN: %clangxx -shared -fPIC -o /dev/null -v -fxray-instrument %s 2>&1 | \
+// RUN:     FileCheck %s --check-prefix=SHARED
+// RUN: %clangxx -static -o /dev/null -v -fxray-instrument %s 2>&1 -DMAIN | \
+// RUN:     FileCheck %s --check-prefix=STATIC
+// RUN: %clangxx -static -fPIE -o /dev/null -v -fxray-instrument %s 2>&1 \
+// RUN:     -DMAIN | FileCheck %s --check-prefix=STATIC
+//
+// SHARED-NOT: {{clang_rt\.xray-}}
+// STATIC: {{clang_rt\.xray-}}
+int foo() { return 42; }
+
+#ifdef MAIN
+int main() { return foo(); }
+#endif
