2 files changed, 36 insertions, 6 deletions

diff --git a/llvm/lib/CodeGen/MachineOutliner.cpp b/llvm/lib/CodeGen/MachineOutliner.cpp
index 8e92cd482d8..da084d961f6 100644
--- a/llvm/lib/CodeGen/MachineOutliner.cpp
+++ b/llvm/lib/CodeGen/MachineOutliner.cpp
@@ -688,6 +688,12 @@ struct MachineOutliner : public ModulePass {
   /// linkonceodr linkage.
   bool OutlineFromLinkOnceODRs = false;
 
+  /// Set to true if the outliner should run on all functions in the module
+  /// considered safe for outlining.
+  /// Set to true by default for compatibility with llc's -run-pass option.
+  /// Set when the pass is constructed in TargetPassConfig.
+  bool RunOnAllFunctions = true;
+
   // Collection of IR functions created by the outliner.
   std::vector<Function *> CreatedIRFunctions;
 
@@ -806,8 +812,10 @@ struct MachineOutliner : public ModulePass {
 char MachineOutliner::ID = 0;
 
 namespace llvm {
-ModulePass *createMachineOutlinerPass() {
-  return new MachineOutliner();
+ModulePass *createMachineOutlinerPass(bool RunOnAllFunctions) {
+  MachineOutliner *OL = new MachineOutliner();
+  OL->RunOnAllFunctions = RunOnAllFunctions;
+  return OL;
 }
 
 } // namespace llvm
@@ -1331,6 +1339,20 @@ bool MachineOutliner::runOnModule(Module &M) {
   const TargetRegisterInfo *TRI = STI.getRegisterInfo();
   const TargetInstrInfo *TII = STI.getInstrInfo();
 
+  // If the user passed -enable-machine-outliner=always or
+  // -enable-machine-outliner, the pass will run on all functions in the module.
+  // Otherwise, if the target supports default outlining, it will run on all
+  // functions deemed by the target to be worth outlining from by default. Tell
+  // the user how the outliner is running.
+  LLVM_DEBUG(
+    dbgs() << "Machine Outliner: Running on ";
+    if (RunOnAllFunctions)
+      dbgs() << "all functions";
+    else
+      dbgs() << "target-default functions";
+    dbgs() << "\n"
+  );
+
   // If the user specifies that they want to outline from linkonceodrs, set
   // it here.
   OutlineFromLinkOnceODRs = EnableLinkOnceODROutlining;
@@ -1355,6 +1377,9 @@ bool MachineOutliner::runOnModule(Module &M) {
     if (!MF)
       continue;
 
+    if (!RunOnAllFunctions && !TII->shouldOutlineFromFunctionByDefault(*MF))
+      continue;
+
     // We have a MachineFunction. Ask the target if it's suitable for outlining.
     // If it isn't, then move on to the next Function in the module.
     if (!TII->isFunctionSafeToOutlineFrom(*MF, OutlineFromLinkOnceODRs))
diff --git a/llvm/lib/CodeGen/TargetPassConfig.cpp b/llvm/lib/CodeGen/TargetPassConfig.cpp
index dfdf676e40f..3fca2f4ee4f 100644
--- a/llvm/lib/CodeGen/TargetPassConfig.cpp
+++ b/llvm/lib/CodeGen/TargetPassConfig.cpp
@@ -111,11 +111,11 @@ static cl::opt<bool> VerifyMachineCode("verify-machineinstrs", cl::Hidden,
     cl::desc("Verify generated machine code"),
     cl::init(false),
     cl::ZeroOrMore);
-enum RunOutliner { AlwaysOutline, NeverOutline };
+enum RunOutliner { AlwaysOutline, NeverOutline, TargetDefault };
 // Enable or disable the MachineOutliner.
 static cl::opt<RunOutliner> EnableMachineOutliner(
     "enable-machine-outliner", cl::desc("Enable the machine outliner"),
-    cl::Hidden, cl::ValueOptional, cl::init(NeverOutline),
+    cl::Hidden, cl::ValueOptional, cl::init(TargetDefault),
     cl::values(clEnumValN(AlwaysOutline, "always",
                           "Run on all functions guaranteed to be beneficial"),
                clEnumValN(NeverOutline, "never", "Disable all outlining"),
@@ -914,8 +914,13 @@ void TargetPassConfig::addMachinePasses() {
   addPass(&PatchableFunctionID, false);
 
   if (TM->Options.EnableMachineOutliner && getOptLevel() != CodeGenOpt::None &&
-      EnableMachineOutliner == AlwaysOutline)
-    addPass(createMachineOutlinerPass());
+      EnableMachineOutliner != NeverOutline) {
+    bool RunOnAllFunctions = (EnableMachineOutliner == AlwaysOutline);
+    bool AddOutliner = RunOnAllFunctions ||
+                       TM->Options.SupportsDefaultOutlining;
+    if (AddOutliner)
+      addPass(createMachineOutlinerPass(RunOnAllFunctions));
+  }
 
   // Add passes that directly emit MI after all other MI passes.
   addPreEmitPass2();