Add XRay flags to Clang. We implement two flags to control the XRay behaviour:

-fxray-instrument: enables XRay annotation of IR
-fxray-instruction-threshold: configures the threshold for function size (looking at IR instructions), and allow LLVM to decide whether to add the nop sleds later on in the process.

Also implements the related xray_always_instrument and xray_never_instrument function attributes.

Patch by Dean Michael Berris.

llvm-svn: 275330

1 files changed, 37 insertions, 0 deletions

diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index d3844dd..e4dd0c6 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -3181,6 +3181,28 @@ static bool addSanitizerRuntimes(const ToolChain &TC, const ArgList &Args,
   return !StaticRuntimes.empty();
 }
 
+static bool addXRayRuntime(const ToolChain &TC, const ArgList &Args,
+                           ArgStringList &CmdArgs) {
+  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;
+}
+
+static void linkXRayRuntimeDeps(const ToolChain &TC, ArgStringList &CmdArgs) {
+  CmdArgs.push_back("--no-as-needed");
+  CmdArgs.push_back("-lpthread");
+  CmdArgs.push_back("-lrt");
+  CmdArgs.push_back("-lm");
+  CmdArgs.push_back("-latomic");
+  if (TC.getTriple().getOS() != llvm::Triple::FreeBSD)
+    CmdArgs.push_back("-ldl");
+}
+
 static bool areOptimizationsEnabled(const ArgList &Args) {
   // Find the last -O arg and see if it is non-zero.
   if (Arg *A = Args.getLastArg(options::OPT_O_Group))
@@ -4582,6 +4604,17 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
 
   Args.AddAllArgs(CmdArgs, options::OPT_finstrument_functions);
 
+  if (Args.hasFlag(options::OPT_fxray_instrument,
+                   options::OPT_fnoxray_instrument, false)) {
+    CmdArgs.push_back("-fxray-instrument");
+    if (const Arg *A =
+            Args.getLastArg(options::OPT_fxray_instruction_threshold_,
+                            options::OPT_fxray_instruction_threshold_EQ)) {
+      CmdArgs.push_back("-fxray-instruction-threshold");
+      CmdArgs.push_back(A->getValue());
+    }
+  }
+
   addPGOAndCoverageFlags(C, D, Output, Args, CmdArgs);
 
   // Add runtime flag for PS4 when PGO or Coverage are enabled.
@@ -9390,6 +9423,7 @@ void gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("--no-demangle");
 
   bool NeedsSanitizerDeps = addSanitizerRuntimes(ToolChain, Args, CmdArgs);
+  bool NeedsXRayDeps = addXRayRuntime(ToolChain, Args, CmdArgs);
   AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs);
   // The profile runtime also needs access to system libraries.
   getToolChain().addProfileRTLibs(Args, CmdArgs);
@@ -9416,6 +9450,9 @@ void gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
       if (NeedsSanitizerDeps)
         linkSanitizerRuntimeDeps(ToolChain, CmdArgs);
 
+      if (NeedsXRayDeps)
+        linkXRayRuntimeDeps(ToolChain, CmdArgs);
+
       bool WantPthread = Args.hasArg(options::OPT_pthread) ||
                          Args.hasArg(options::OPT_pthreads);