[RISCV GlobalISel] Adding initial GlobalISel infrastructure

Summary:
Add an initial GlobalISel skeleton for RISCV. It can only run ir translator for `ret void`.

Patch by Andrew Wei

Reviewers: asb, sabuasal, apazos, lenary, simoncook, lewis-revill, edward-jones, rogfer01, xiangzhai, rovka, Petar.Avramovic, mgorny, dsanders

Reviewed By: dsanders

Subscribers: pzheng, s.egerton, dsanders, hiraditya, rbar, johnrusso, niosHD, kito-cheng, shiva0217, jrtc27, MaskRay, zzheng, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, psnobl, benna, Jim, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65219

llvm-svn: 369467
diff --git a/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp b/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
index c9614cc..5ffc6ed 100644
--- a/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
+++ b/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
@@ -17,6 +17,10 @@
 #include "TargetInfo/RISCVTargetInfo.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/CodeGen/GlobalISel/IRTranslator.h"
+#include "llvm/CodeGen/GlobalISel/InstructionSelect.h"
+#include "llvm/CodeGen/GlobalISel/Legalizer.h"
+#include "llvm/CodeGen/GlobalISel/RegBankSelect.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
 #include "llvm/CodeGen/TargetPassConfig.h"
@@ -30,6 +34,7 @@
   RegisterTargetMachine<RISCVTargetMachine> X(getTheRISCV32Target());
   RegisterTargetMachine<RISCVTargetMachine> Y(getTheRISCV64Target());
   auto PR = PassRegistry::getPassRegistry();
+  initializeGlobalISel(*PR);
   initializeRISCVExpandPseudoPass(*PR);
 }
 
@@ -80,6 +85,10 @@
 
   void addIRPasses() override;
   bool addInstSelector() override;
+  bool addIRTranslator() override;
+  bool addLegalizeMachineIR() override;
+  bool addRegBankSelect() override;
+  bool addGlobalInstructionSelect() override;
   void addPreEmitPass() override;
   void addPreEmitPass2() override;
   void addPreRegAlloc() override;
@@ -101,6 +110,26 @@
   return false;
 }
 
+bool RISCVPassConfig::addIRTranslator() {
+  addPass(new IRTranslator());
+  return false;
+}
+
+bool RISCVPassConfig::addLegalizeMachineIR() {
+  addPass(new Legalizer());
+  return false;
+}
+
+bool RISCVPassConfig::addRegBankSelect() {
+  addPass(new RegBankSelect());
+  return false;
+}
+
+bool RISCVPassConfig::addGlobalInstructionSelect() {
+  addPass(new InstructionSelect());
+  return false;
+}
+
 void RISCVPassConfig::addPreEmitPass() { addPass(&BranchRelaxationPassID); }
 
 void RISCVPassConfig::addPreEmitPass2() {