[MachineOutliner] NFC: Move EnableLinkOnceODROutlining into MachineOutliner.cpp

This moves the EnableLinkOnceODROutlining flag from TargetPassConfig.cpp into
MachineOutliner.cpp. It also removes OutlineFromLinkOnceODRs from the
MachineOutliner constructor. This is now handled by the moved command-line
flag.

llvm-svn: 330373

llvm/include/llvm/CodeGen/Passes.h

@@ -419,7 +419,7 @@ namespace llvm {
 
   /// This pass performs outlining on machine instructions directly before
   /// printing assembly.
-  ModulePass *createMachineOutlinerPass(bool OutlineFromLinkOnceODRs = false);
+  ModulePass *createMachineOutlinerPass();
 
   /// This pass expands the experimental reduction intrinsics into sequences of
   /// shuffles.

llvm/lib/CodeGen/MachineOutliner.cpp

@@ -71,6 +71,7 @@
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Mangler.h"
 #include "llvm/Support/Allocator.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 #include <functional>
@@ -87,6 +88,17 @@ using namespace ore;
 STATISTIC(NumOutlined, "Number of candidates outlined");
 STATISTIC(FunctionsCreated, "Number of functions created");
 
+// Set to true if the user wants the outliner to run on linkonceodr linkage
+// functions. This is false by default because the linker can dedupe linkonceodr
+// functions. Since the outliner is confined to a single module (modulo LTO),
+// this is off by default. It should, however, be the default behaviour in
+// LTO.
+static cl::opt<bool> EnableLinkOnceODROutlining(
+    "enable-linkonceodr-outlining",
+    cl::Hidden,
+    cl::desc("Enable the machine outliner on linkonceodr functions"),
+    cl::init(false));
+
 namespace {
 
 /// \brief An individual sequence of instructions to be replaced with a call to
@@ -813,8 +825,7 @@ struct MachineOutliner : public ModulePass {
     ModulePass::getAnalysisUsage(AU);
   }
 
-  MachineOutliner(bool OutlineFromLinkOnceODRs = false)
-      : ModulePass(ID), OutlineFromLinkOnceODRs(OutlineFromLinkOnceODRs) {
+  MachineOutliner() : ModulePass(ID) {
     initializeMachineOutlinerPass(*PassRegistry::getPassRegistry());
   }
 
@@ -910,8 +921,8 @@ struct MachineOutliner : public ModulePass {
 char MachineOutliner::ID = 0;
 
 namespace llvm {
-ModulePass *createMachineOutlinerPass(bool OutlineFromLinkOnceODRs) {
-  return new MachineOutliner(OutlineFromLinkOnceODRs);
+ModulePass *createMachineOutlinerPass() {
+  return new MachineOutliner();
 }
 
 } // namespace llvm
@@ -1425,6 +1436,10 @@ bool MachineOutliner::runOnModule(Module &M) {
     return false;
   }
 
+  // If the user specifies that they want to outline from linkonceodrs, set
+  // it here.
+  OutlineFromLinkOnceODRs = EnableLinkOnceODROutlining;
+
   InstructionMapper Mapper;
 
   // Build instruction mappings for each function in the module. Start by

llvm/lib/CodeGen/TargetPassConfig.cpp

@@ -114,11 +114,6 @@ static cl::opt<bool> VerifyMachineCode("verify-machineinstrs", cl::Hidden,
 static cl::opt<bool> EnableMachineOutliner("enable-machine-outliner",
     cl::Hidden,
     cl::desc("Enable machine outliner"));
-static cl::opt<bool> EnableLinkOnceODROutlining(
-    "enable-linkonceodr-outlining",
-    cl::Hidden,
-    cl::desc("Enable the machine outliner on linkonceodr functions"),
-    cl::init(false));
 // Enable or disable FastISel. Both options are needed, because
 // FastISel is enabled by default with -fast, and we wish to be
 // able to enable or disable fast-isel independently from -O0.
@@ -907,7 +902,7 @@ void TargetPassConfig::addMachinePasses() {
   addPass(&PatchableFunctionID, false);
 
   if (EnableMachineOutliner)
-    PM->add(createMachineOutlinerPass(EnableLinkOnceODROutlining));
+    addPass(createMachineOutlinerPass());
 
   // Add passes that directly emit MI after all other MI passes.
   addPreEmitPass2();