2 files changed, 49 insertions, 17 deletions

diff --git a/llvm/lib/Target/X86/X86Subtarget.cpp b/llvm/lib/Target/X86/X86Subtarget.cpp
index bada96df869..493084f795f 100644
--- a/llvm/lib/Target/X86/X86Subtarget.cpp
+++ b/llvm/lib/Target/X86/X86Subtarget.cpp
@@ -353,6 +353,33 @@ X86Subtarget &X86Subtarget::initializeSubtargetDependencies(StringRef CPU,
   return *this;
 }
 
+namespace {
+
+struct X86GISelActualAccessor : public GISelAccessor {
+  std::unique_ptr<CallLowering> CallLoweringInfo;
+  std::unique_ptr<LegalizerInfo> Legalizer;
+  std::unique_ptr<RegisterBankInfo> RegBankInfo;
+  std::unique_ptr<InstructionSelector> InstSelector;
+
+  const CallLowering *getCallLowering() const override {
+    return CallLoweringInfo.get();
+  }
+
+  const InstructionSelector *getInstructionSelector() const override {
+    return InstSelector.get();
+  }
+
+  const LegalizerInfo *getLegalizerInfo() const override {
+    return Legalizer.get();
+  }
+
+  const RegisterBankInfo *getRegBankInfo() const override {
+    return RegBankInfo.get();
+  }
+};
+
+} // end anonymous namespace
+
 X86Subtarget::X86Subtarget(const Triple &TT, StringRef CPU, StringRef FS,
                            const X86TargetMachine &TM,
                            unsigned StackAlignOverride)
@@ -377,29 +404,35 @@ X86Subtarget::X86Subtarget(const Triple &TT, StringRef CPU, StringRef FS,
     setPICStyle(PICStyles::StubPIC);
   else if (isTargetELF())
     setPICStyle(PICStyles::GOT);
+  X86GISelActualAccessor *GISel = new X86GISelActualAccessor();
 
-  CallLoweringInfo.reset(new X86CallLowering(*getTargetLowering()));
-  Legalizer.reset(new X86LegalizerInfo(*this, TM));
+  GISel->CallLoweringInfo.reset(new X86CallLowering(*getTargetLowering()));
+  GISel->Legalizer.reset(new X86LegalizerInfo(*this, TM));
 
   auto *RBI = new X86RegisterBankInfo(*getRegisterInfo());
-  RegBankInfo.reset(RBI);
-  InstSelector.reset(createX86InstructionSelector(TM, *this, *RBI));
+  GISel->RegBankInfo.reset(RBI);
+  GISel->InstSelector.reset(createX86InstructionSelector(TM, *this, *RBI));
+  setGISelAccessor(*GISel);
 }
 
 const CallLowering *X86Subtarget::getCallLowering() const {
-  return CallLoweringInfo.get();
+  assert(GISel && "Access to GlobalISel APIs not set");
+  return GISel->getCallLowering();
 }
 
 const InstructionSelector *X86Subtarget::getInstructionSelector() const {
-  return InstSelector.get();
+  assert(GISel && "Access to GlobalISel APIs not set");
+  return GISel->getInstructionSelector();
 }
 
 const LegalizerInfo *X86Subtarget::getLegalizerInfo() const {
-  return Legalizer.get();
+  assert(GISel && "Access to GlobalISel APIs not set");
+  return GISel->getLegalizerInfo();
 }
 
 const RegisterBankInfo *X86Subtarget::getRegBankInfo() const {
-  return RegBankInfo.get();
+  assert(GISel && "Access to GlobalISel APIs not set");
+  return GISel->getRegBankInfo();
 }
 
 bool X86Subtarget::enableEarlyIfConversion() const {
diff --git a/llvm/lib/Target/X86/X86Subtarget.h b/llvm/lib/Target/X86/X86Subtarget.h
index 2d9eef978df..427a0001bef 100644
--- a/llvm/lib/Target/X86/X86Subtarget.h
+++ b/llvm/lib/Target/X86/X86Subtarget.h
@@ -20,10 +20,7 @@
 #include "X86SelectionDAGInfo.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Triple.h"
-#include "llvm/CodeGen/GlobalISel/CallLowering.h"
-#include "llvm/CodeGen/GlobalISel/InstructionSelector.h"
-#include "llvm/CodeGen/GlobalISel/LegalizerInfo.h"
-#include "llvm/CodeGen/GlobalISel/RegisterBankInfo.h"
+#include "llvm/CodeGen/GlobalISel/GISelAccessor.h"
 #include "llvm/IR/CallingConv.h"
 #include "llvm/MC/MCInstrItineraries.h"
 #include "llvm/Target/TargetMachine.h"
@@ -317,11 +314,10 @@ protected:
   /// Instruction itineraries for scheduling
   InstrItineraryData InstrItins;
 
-  /// GlobalISel related APIs.
-  std::unique_ptr<CallLowering> CallLoweringInfo;
-  std::unique_ptr<LegalizerInfo> Legalizer;
-  std::unique_ptr<RegisterBankInfo> RegBankInfo;
-  std::unique_ptr<InstructionSelector> InstSelector;
+  /// Gather the accessor points to GlobalISel-related APIs.
+  /// This is used to avoid ifndefs spreading around while GISel is
+  /// an optional library.
+  std::unique_ptr<GISelAccessor> GISel;
 
 private:
   /// Override the stack alignment.
@@ -350,6 +346,9 @@ public:
   X86Subtarget(const Triple &TT, StringRef CPU, StringRef FS,
                const X86TargetMachine &TM, unsigned StackAlignOverride);
 
+  /// This object will take onwership of \p GISelAccessor.
+  void setGISelAccessor(GISelAccessor &GISel) { this->GISel.reset(&GISel); }
+
   const X86TargetLowering *getTargetLowering() const override {
     return &TLInfo;
   }