[PATCH] D45354: [XRay][clang] Add a flag to enable/disable linking XRay deps explicitly

[Dean Michael Berris via Phabricator via cfe-commits]

dberris created this revision.
dberris added reviewers: eizan, echristo, chandlerc.

This change introduces `-fxray-link-deps` and `-fnoxray-link-deps`. The
`-fnoxray-link-deps` allows for directly controlling which specific XRay
runtime to link. The default is for clang to link the XRay runtime that
is shipped with the compiler (if there are any), but users may want to
explicitly add the XRay dependencies from other locations or other
means.


https://reviews.llvm.org/D45354

Files:
  clang/include/clang/Driver/Options.td
  clang/include/clang/Driver/XRayArgs.h
  clang/lib/Driver/XRayArgs.cpp
  clang/test/Driver/XRay/xray-nolinkdeps.cpp


Index: clang/test/Driver/XRay/xray-nolinkdeps.cpp
===================================================================
--- /dev/null
+++ clang/test/Driver/XRay/xray-nolinkdeps.cpp
@@ -0,0 +1,6 @@
+// RUN: %clang -v -o /dev/null -fxray-instrument -fnoxray-link-deps %s -### \
+// RUN:     2>&1 | FileCheck --check-prefix DISABLE %s
+// RUN: %clang -v -o /dev/null -fxray-instrument -fxray-link-deps %s -### \
+// RUN:     2>&1 | FileCheck --check-prefix ENABLE %s
+// ENABLE: clang_rt.xray
+// DISABLE-NOT: clang_rt.xray
Index: clang/lib/Driver/XRayArgs.cpp
===================================================================
--- clang/lib/Driver/XRayArgs.cpp
+++ clang/lib/Driver/XRayArgs.cpp
@@ -76,6 +76,10 @@
                      options::OPT_fnoxray_always_emit_customevents, false))
       XRayAlwaysEmitCustomEvents = true;
 
+    if (!Args.hasFlag(options::OPT_fxray_link_deps,
+                      options::OPT_fnoxray_link_deps, true))
+      XRayRT = false;
+
     // Validate the always/never attribute files. We also make sure that they
     // are treated as actual dependencies.
     for (const auto &Filename :
Index: clang/include/clang/Driver/XRayArgs.h
===================================================================
--- clang/include/clang/Driver/XRayArgs.h
+++ clang/include/clang/Driver/XRayArgs.h
@@ -25,14 +25,15 @@
   bool XRayInstrument = false;
   int InstructionThreshold = 200;
   bool XRayAlwaysEmitCustomEvents = false;
+  bool XRayRT = true;
 
 public:
   /// Parses the XRay arguments from an argument list.
   XRayArgs(const ToolChain &TC, const llvm::opt::ArgList &Args);
   void addArgs(const ToolChain &TC, const llvm::opt::ArgList &Args,
                llvm::opt::ArgStringList &CmdArgs, types::ID InputType) const;
 
-  bool needsXRayRt() const { return XRayInstrument; }
+  bool needsXRayRt() const { return XRayInstrument && XRayRT; }
 };
 
 } // namespace driver
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -1107,6 +1107,12 @@
 def fnoxray_always_emit_customevents : Flag<["-"], "fno-xray-always-emit-customevents">, Group<f_Group>,
   Flags<[CC1Option]>;
 
+def fxray_link_deps : Flag<["-"], "fxray-link-deps">, Group<f_Group>,
+  Flags<[CC1Option]>,
+  HelpText<"Tells clang to add the link dependencies for XRay.">;
+def fnoxray_link_deps : Flag<["-"], "fnoxray-link-deps">, Group<f_Group>,
+  Flags<[CC1Option]>;
+
 def ffine_grained_bitfield_accesses : Flag<["-"],
   "ffine-grained-bitfield-accesses">, Group<f_clang_Group>, Flags<[CC1Option]>,
   HelpText<"Use separate accesses for bitfields with legal widths and alignments.">;


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