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			804 lines
		
	
	
		
			24 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			804 lines
		
	
	
		
			24 KiB
		
	
	
	
		
			C++
		
	
	
	
| //===-------------- MIRCanonicalizer.cpp - MIR Canonicalizer --------------===//
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| //
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| //                     The LLVM Compiler Infrastructure
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| //
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| // This file is distributed under the University of Illinois Open Source
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| // License. See LICENSE.TXT for details.
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| //
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| //===----------------------------------------------------------------------===//
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| //
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| // The purpose of this pass is to employ a canonical code transformation so
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| // that code compiled with slightly different IR passes can be diffed more
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| // effectively than otherwise. This is done by renaming vregs in a given
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| // LiveRange in a canonical way. This pass also does a pseudo-scheduling to
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| // move defs closer to their use inorder to reduce diffs caused by slightly
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| // different schedules.
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| //
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| // Basic Usage:
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| //
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| // llc -o - -run-pass mir-canonicalizer example.mir
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| //
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| // Reorders instructions canonically.
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| // Renames virtual register operands canonically.
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| // Strips certain MIR artifacts (optionally).
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| //
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| //===----------------------------------------------------------------------===//
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| 
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| #include "llvm/ADT/PostOrderIterator.h"
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| #include "llvm/ADT/STLExtras.h"
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| #include "llvm/CodeGen/MachineFunctionPass.h"
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| #include "llvm/CodeGen/MachineInstrBuilder.h"
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| #include "llvm/CodeGen/MachineRegisterInfo.h"
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| #include "llvm/CodeGen/Passes.h"
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| #include "llvm/Support/raw_ostream.h"
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| 
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| #include <queue>
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| 
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| using namespace llvm;
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| 
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| namespace llvm {
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| extern char &MIRCanonicalizerID;
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| } // namespace llvm
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| 
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| #define DEBUG_TYPE "mir-canonicalizer"
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| 
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| static cl::opt<unsigned>
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|     CanonicalizeFunctionNumber("canon-nth-function", cl::Hidden, cl::init(~0u),
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|                                cl::value_desc("N"),
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|                                cl::desc("Function number to canonicalize."));
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| 
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| static cl::opt<unsigned> CanonicalizeBasicBlockNumber(
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|     "canon-nth-basicblock", cl::Hidden, cl::init(~0u), cl::value_desc("N"),
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|     cl::desc("BasicBlock number to canonicalize."));
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| 
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| namespace {
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| 
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| class MIRCanonicalizer : public MachineFunctionPass {
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| public:
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|   static char ID;
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|   MIRCanonicalizer() : MachineFunctionPass(ID) {}
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| 
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|   StringRef getPassName() const override {
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|     return "Rename register operands in a canonical ordering.";
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|   }
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| 
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|   void getAnalysisUsage(AnalysisUsage &AU) const override {
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|     AU.setPreservesCFG();
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|     MachineFunctionPass::getAnalysisUsage(AU);
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|   }
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| 
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|   bool runOnMachineFunction(MachineFunction &MF) override;
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| };
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| 
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| } // end anonymous namespace
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| 
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| enum VRType { RSE_Reg = 0, RSE_FrameIndex, RSE_NewCandidate };
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| class TypedVReg {
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|   VRType type;
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|   unsigned reg;
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| 
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| public:
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|   TypedVReg(unsigned reg) : type(RSE_Reg), reg(reg) {}
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|   TypedVReg(VRType type) : type(type), reg(~0U) {
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|     assert(type != RSE_Reg && "Expected a non-register type.");
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|   }
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| 
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|   bool isReg() const { return type == RSE_Reg; }
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|   bool isFrameIndex() const { return type == RSE_FrameIndex; }
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|   bool isCandidate() const { return type == RSE_NewCandidate; }
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| 
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|   VRType getType() const { return type; }
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|   unsigned getReg() const {
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|     assert(this->isReg() && "Expected a virtual or physical register.");
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|     return reg;
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|   }
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| };
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| 
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| char MIRCanonicalizer::ID;
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| 
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| char &llvm::MIRCanonicalizerID = MIRCanonicalizer::ID;
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| 
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| INITIALIZE_PASS_BEGIN(MIRCanonicalizer, "mir-canonicalizer",
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|                       "Rename Register Operands Canonically", false, false)
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| 
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| INITIALIZE_PASS_END(MIRCanonicalizer, "mir-canonicalizer",
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|                     "Rename Register Operands Canonically", false, false)
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| 
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| static std::vector<MachineBasicBlock *> GetRPOList(MachineFunction &MF) {
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|   ReversePostOrderTraversal<MachineBasicBlock *> RPOT(&*MF.begin());
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|   std::vector<MachineBasicBlock *> RPOList;
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|   for (auto MBB : RPOT) {
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|     RPOList.push_back(MBB);
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|   }
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| 
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|   return RPOList;
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| }
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| 
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| static bool
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| rescheduleLexographically(std::vector<MachineInstr *> instructions,
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|                           MachineBasicBlock *MBB,
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|                           std::function<MachineBasicBlock::iterator()> getPos) {
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| 
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|   bool Changed = false;
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|   using StringInstrPair = std::pair<std::string, MachineInstr *>;
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|   std::vector<StringInstrPair> StringInstrMap;
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| 
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|   for (auto *II : instructions) {
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|     std::string S;
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|     raw_string_ostream OS(S);
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|     II->print(OS);
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|     OS.flush();
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| 
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|     // Trim the assignment, or start from the begining in the case of a store.
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|     const size_t i = S.find("=");
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|     StringInstrMap.push_back({(i == std::string::npos) ? S : S.substr(i), II});
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|   }
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| 
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|   llvm::sort(StringInstrMap,
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|              [](const StringInstrPair &a, const StringInstrPair &b) -> bool {
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|                return (a.first < b.first);
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|              });
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| 
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|   for (auto &II : StringInstrMap) {
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| 
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|     LLVM_DEBUG({
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|       dbgs() << "Splicing ";
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|       II.second->dump();
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|       dbgs() << " right before: ";
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|       getPos()->dump();
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|     });
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| 
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|     Changed = true;
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|     MBB->splice(getPos(), MBB, II.second);
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|   }
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| 
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|   return Changed;
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| }
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| 
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| static bool rescheduleCanonically(unsigned &PseudoIdempotentInstCount,
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|                                   MachineBasicBlock *MBB) {
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| 
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|   bool Changed = false;
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| 
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|   // Calculates the distance of MI from the begining of its parent BB.
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|   auto getInstrIdx = [](const MachineInstr &MI) {
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|     unsigned i = 0;
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|     for (auto &CurMI : *MI.getParent()) {
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|       if (&CurMI == &MI)
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|         return i;
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|       i++;
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|     }
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|     return ~0U;
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|   };
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| 
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|   // Pre-Populate vector of instructions to reschedule so that we don't
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|   // clobber the iterator.
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|   std::vector<MachineInstr *> Instructions;
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|   for (auto &MI : *MBB) {
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|     Instructions.push_back(&MI);
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|   }
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| 
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|   std::map<MachineInstr *, std::vector<MachineInstr *>> MultiUsers;
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|   std::vector<MachineInstr *> PseudoIdempotentInstructions;
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|   std::vector<unsigned> PhysRegDefs;
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|   for (auto *II : Instructions) {
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|     for (unsigned i = 1; i < II->getNumOperands(); i++) {
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|       MachineOperand &MO = II->getOperand(i);
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|       if (!MO.isReg())
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|         continue;
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| 
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|       if (TargetRegisterInfo::isVirtualRegister(MO.getReg()))
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|         continue;
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| 
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|       if (!MO.isDef())
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|         continue;
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| 
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|       PhysRegDefs.push_back(MO.getReg());
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|     }
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|   }
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| 
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|   for (auto *II : Instructions) {
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|     if (II->getNumOperands() == 0)
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|       continue;
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|     if (II->mayLoadOrStore())
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|       continue;
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| 
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|     MachineOperand &MO = II->getOperand(0);
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|     if (!MO.isReg() || !TargetRegisterInfo::isVirtualRegister(MO.getReg()))
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|       continue;
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|     if (!MO.isDef())
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|       continue;
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| 
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|     bool IsPseudoIdempotent = true;
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|     for (unsigned i = 1; i < II->getNumOperands(); i++) {
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| 
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|       if (II->getOperand(i).isImm()) {
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|         continue;
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|       }
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| 
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|       if (II->getOperand(i).isReg()) {
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|         if (!TargetRegisterInfo::isVirtualRegister(II->getOperand(i).getReg()))
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|           if (llvm::find(PhysRegDefs, II->getOperand(i).getReg()) ==
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|               PhysRegDefs.end()) {
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|             continue;
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|           }
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|       }
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| 
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|       IsPseudoIdempotent = false;
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|       break;
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|     }
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| 
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|     if (IsPseudoIdempotent) {
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|       PseudoIdempotentInstructions.push_back(II);
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|       continue;
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|     }
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| 
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|     LLVM_DEBUG(dbgs() << "Operand " << 0 << " of "; II->dump(); MO.dump(););
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| 
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|     MachineInstr *Def = II;
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|     unsigned Distance = ~0U;
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|     MachineInstr *UseToBringDefCloserTo = nullptr;
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|     MachineRegisterInfo *MRI = &MBB->getParent()->getRegInfo();
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|     for (auto &UO : MRI->use_nodbg_operands(MO.getReg())) {
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|       MachineInstr *UseInst = UO.getParent();
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| 
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|       const unsigned DefLoc = getInstrIdx(*Def);
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|       const unsigned UseLoc = getInstrIdx(*UseInst);
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|       const unsigned Delta = (UseLoc - DefLoc);
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| 
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|       if (UseInst->getParent() != Def->getParent())
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|         continue;
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|       if (DefLoc >= UseLoc)
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|         continue;
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| 
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|       if (Delta < Distance) {
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|         Distance = Delta;
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|         UseToBringDefCloserTo = UseInst;
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|       }
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|     }
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| 
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|     const auto BBE = MBB->instr_end();
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|     MachineBasicBlock::iterator DefI = BBE;
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|     MachineBasicBlock::iterator UseI = BBE;
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| 
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|     for (auto BBI = MBB->instr_begin(); BBI != BBE; ++BBI) {
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| 
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|       if (DefI != BBE && UseI != BBE)
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|         break;
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| 
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|       if (&*BBI == Def) {
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|         DefI = BBI;
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|         continue;
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|       }
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| 
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|       if (&*BBI == UseToBringDefCloserTo) {
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|         UseI = BBI;
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|         continue;
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|       }
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|     }
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| 
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|     if (DefI == BBE || UseI == BBE)
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|       continue;
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| 
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|     LLVM_DEBUG({
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|       dbgs() << "Splicing ";
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|       DefI->dump();
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|       dbgs() << " right before: ";
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|       UseI->dump();
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|     });
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| 
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|     MultiUsers[UseToBringDefCloserTo].push_back(Def);
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|     Changed = true;
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|     MBB->splice(UseI, MBB, DefI);
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|   }
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| 
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|   // Sort the defs for users of multiple defs lexographically.
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|   for (const auto &E : MultiUsers) {
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| 
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|     auto UseI =
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|         std::find_if(MBB->instr_begin(), MBB->instr_end(),
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|                      [&](MachineInstr &MI) -> bool { return &MI == E.first; });
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| 
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|     if (UseI == MBB->instr_end())
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|       continue;
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| 
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|     LLVM_DEBUG(
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|         dbgs() << "Rescheduling Multi-Use Instructions Lexographically.";);
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|     Changed |= rescheduleLexographically(
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|         E.second, MBB, [&]() -> MachineBasicBlock::iterator { return UseI; });
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|   }
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| 
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|   PseudoIdempotentInstCount = PseudoIdempotentInstructions.size();
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|   LLVM_DEBUG(
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|       dbgs() << "Rescheduling Idempotent Instructions Lexographically.";);
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|   Changed |= rescheduleLexographically(
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|       PseudoIdempotentInstructions, MBB,
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|       [&]() -> MachineBasicBlock::iterator { return MBB->begin(); });
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| 
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|   return Changed;
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| }
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| 
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| static bool propagateLocalCopies(MachineBasicBlock *MBB) {
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|   bool Changed = false;
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|   MachineRegisterInfo &MRI = MBB->getParent()->getRegInfo();
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| 
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|   std::vector<MachineInstr *> Copies;
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|   for (MachineInstr &MI : MBB->instrs()) {
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|     if (MI.isCopy())
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|       Copies.push_back(&MI);
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|   }
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| 
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|   for (MachineInstr *MI : Copies) {
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| 
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|     if (!MI->getOperand(0).isReg())
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|       continue;
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|     if (!MI->getOperand(1).isReg())
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|       continue;
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| 
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|     const unsigned Dst = MI->getOperand(0).getReg();
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|     const unsigned Src = MI->getOperand(1).getReg();
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| 
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|     if (!TargetRegisterInfo::isVirtualRegister(Dst))
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|       continue;
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|     if (!TargetRegisterInfo::isVirtualRegister(Src))
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|       continue;
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|     if (MRI.getRegClass(Dst) != MRI.getRegClass(Src))
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|       continue;
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| 
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|     for (auto UI = MRI.use_begin(Dst); UI != MRI.use_end(); ++UI) {
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|       MachineOperand *MO = &*UI;
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|       MO->setReg(Src);
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|       Changed = true;
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|     }
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| 
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|     MI->eraseFromParent();
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|   }
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| 
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|   return Changed;
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| }
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| 
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| /// Here we find our candidates. What makes an interesting candidate?
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| /// An candidate for a canonicalization tree root is normally any kind of
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| /// instruction that causes side effects such as a store to memory or a copy to
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| /// a physical register or a return instruction. We use these as an expression
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| /// tree root that we walk inorder to build a canonical walk which should result
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| /// in canoncal vreg renaming.
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| static std::vector<MachineInstr *> populateCandidates(MachineBasicBlock *MBB) {
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|   std::vector<MachineInstr *> Candidates;
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|   MachineRegisterInfo &MRI = MBB->getParent()->getRegInfo();
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| 
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|   for (auto II = MBB->begin(), IE = MBB->end(); II != IE; ++II) {
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|     MachineInstr *MI = &*II;
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| 
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|     bool DoesMISideEffect = false;
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| 
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|     if (MI->getNumOperands() > 0 && MI->getOperand(0).isReg()) {
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|       const unsigned Dst = MI->getOperand(0).getReg();
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|       DoesMISideEffect |= !TargetRegisterInfo::isVirtualRegister(Dst);
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| 
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|       for (auto UI = MRI.use_begin(Dst); UI != MRI.use_end(); ++UI) {
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|         if (DoesMISideEffect)
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|           break;
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|         DoesMISideEffect |= (UI->getParent()->getParent() != MI->getParent());
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|       }
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|     }
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| 
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|     if (!MI->mayStore() && !MI->isBranch() && !DoesMISideEffect)
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|       continue;
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| 
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|     LLVM_DEBUG(dbgs() << "Found Candidate:  "; MI->dump(););
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|     Candidates.push_back(MI);
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|   }
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| 
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|   return Candidates;
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| }
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| 
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| static void doCandidateWalk(std::vector<TypedVReg> &VRegs,
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|                             std::queue<TypedVReg> &RegQueue,
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|                             std::vector<MachineInstr *> &VisitedMIs,
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|                             const MachineBasicBlock *MBB) {
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| 
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|   const MachineFunction &MF = *MBB->getParent();
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|   const MachineRegisterInfo &MRI = MF.getRegInfo();
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| 
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|   while (!RegQueue.empty()) {
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| 
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|     auto TReg = RegQueue.front();
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|     RegQueue.pop();
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| 
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|     if (TReg.isFrameIndex()) {
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|       LLVM_DEBUG(dbgs() << "Popping frame index.\n";);
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|       VRegs.push_back(TypedVReg(RSE_FrameIndex));
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|       continue;
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|     }
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| 
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|     assert(TReg.isReg() && "Expected vreg or physreg.");
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|     unsigned Reg = TReg.getReg();
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| 
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|     if (TargetRegisterInfo::isVirtualRegister(Reg)) {
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|       LLVM_DEBUG({
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|         dbgs() << "Popping vreg ";
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|         MRI.def_begin(Reg)->dump();
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|         dbgs() << "\n";
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|       });
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| 
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|       if (!llvm::any_of(VRegs, [&](const TypedVReg &TR) {
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|             return TR.isReg() && TR.getReg() == Reg;
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|           })) {
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|         VRegs.push_back(TypedVReg(Reg));
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|       }
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|     } else {
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|       LLVM_DEBUG(dbgs() << "Popping physreg.\n";);
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|       VRegs.push_back(TypedVReg(Reg));
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|       continue;
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|     }
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| 
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|     for (auto RI = MRI.def_begin(Reg), RE = MRI.def_end(); RI != RE; ++RI) {
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|       MachineInstr *Def = RI->getParent();
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| 
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|       if (Def->getParent() != MBB)
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|         continue;
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| 
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|       if (llvm::any_of(VisitedMIs,
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|                        [&](const MachineInstr *VMI) { return Def == VMI; })) {
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|         break;
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|       }
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| 
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|       LLVM_DEBUG({
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|         dbgs() << "\n========================\n";
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|         dbgs() << "Visited MI: ";
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|         Def->dump();
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|         dbgs() << "BB Name: " << Def->getParent()->getName() << "\n";
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|         dbgs() << "\n========================\n";
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|       });
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|       VisitedMIs.push_back(Def);
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|       for (unsigned I = 1, E = Def->getNumOperands(); I != E; ++I) {
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| 
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|         MachineOperand &MO = Def->getOperand(I);
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|         if (MO.isFI()) {
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|           LLVM_DEBUG(dbgs() << "Pushing frame index.\n";);
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|           RegQueue.push(TypedVReg(RSE_FrameIndex));
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|         }
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| 
 | |
|         if (!MO.isReg())
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|           continue;
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|         RegQueue.push(TypedVReg(MO.getReg()));
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|       }
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|     }
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|   }
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| }
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| 
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| namespace {
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| class NamedVRegCursor {
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|   MachineRegisterInfo &MRI;
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|   unsigned virtualVRegNumber;
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| 
 | |
| public:
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|   NamedVRegCursor(MachineRegisterInfo &MRI) : MRI(MRI) {
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|     unsigned VRegGapIndex = 0;
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|     const unsigned VR_GAP = (++VRegGapIndex * 1000);
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| 
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|     unsigned I = MRI.createIncompleteVirtualRegister();
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|     const unsigned E = (((I + VR_GAP) / VR_GAP) + 1) * VR_GAP;
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| 
 | |
|     virtualVRegNumber = E;
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|   }
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| 
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|   void SkipVRegs() {
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|     unsigned VRegGapIndex = 1;
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|     const unsigned VR_GAP = (++VRegGapIndex * 1000);
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| 
 | |
|     unsigned I = virtualVRegNumber;
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|     const unsigned E = (((I + VR_GAP) / VR_GAP) + 1) * VR_GAP;
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| 
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|     virtualVRegNumber = E;
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|   }
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| 
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|   unsigned getVirtualVReg() const { return virtualVRegNumber; }
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| 
 | |
|   unsigned incrementVirtualVReg(unsigned incr = 1) {
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|     virtualVRegNumber += incr;
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|     return virtualVRegNumber;
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|   }
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| 
 | |
|   unsigned createVirtualRegister(const TargetRegisterClass *RC) {
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|     std::string S;
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|     raw_string_ostream OS(S);
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|     OS << "namedVReg" << (virtualVRegNumber & ~0x80000000);
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|     OS.flush();
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|     virtualVRegNumber++;
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| 
 | |
|     return MRI.createVirtualRegister(RC, OS.str());
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|   }
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| };
 | |
| } // namespace
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| 
 | |
| static std::map<unsigned, unsigned>
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| GetVRegRenameMap(const std::vector<TypedVReg> &VRegs,
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|                  const std::vector<unsigned> &renamedInOtherBB,
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|                  MachineRegisterInfo &MRI, NamedVRegCursor &NVC) {
 | |
|   std::map<unsigned, unsigned> VRegRenameMap;
 | |
|   bool FirstCandidate = true;
 | |
| 
 | |
|   for (auto &vreg : VRegs) {
 | |
|     if (vreg.isFrameIndex()) {
 | |
|       // We skip one vreg for any frame index because there is a good chance
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|       // (especially when comparing SelectionDAG to GlobalISel generated MIR)
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|       // that in the other file we are just getting an incoming vreg that comes
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|       // from a copy from a frame index. So it's safe to skip by one.
 | |
|       unsigned LastRenameReg = NVC.incrementVirtualVReg();
 | |
|       (void)LastRenameReg;
 | |
|       LLVM_DEBUG(dbgs() << "Skipping rename for FI " << LastRenameReg << "\n";);
 | |
|       continue;
 | |
|     } else if (vreg.isCandidate()) {
 | |
| 
 | |
|       // After the first candidate, for every subsequent candidate, we skip mod
 | |
|       // 10 registers so that the candidates are more likely to start at the
 | |
|       // same vreg number making it more likely that the canonical walk from the
 | |
|       // candidate insruction. We don't need to skip from the first candidate of
 | |
|       // the BasicBlock because we already skip ahead several vregs for each BB.
 | |
|       unsigned LastRenameReg = NVC.getVirtualVReg();
 | |
|       if (FirstCandidate)
 | |
|         NVC.incrementVirtualVReg(LastRenameReg % 10);
 | |
|       FirstCandidate = false;
 | |
|       continue;
 | |
|     } else if (!TargetRegisterInfo::isVirtualRegister(vreg.getReg())) {
 | |
|       unsigned LastRenameReg = NVC.incrementVirtualVReg();
 | |
|       (void)LastRenameReg;
 | |
|       LLVM_DEBUG({
 | |
|         dbgs() << "Skipping rename for Phys Reg " << LastRenameReg << "\n";
 | |
|       });
 | |
|       continue;
 | |
|     }
 | |
| 
 | |
|     auto Reg = vreg.getReg();
 | |
|     if (llvm::find(renamedInOtherBB, Reg) != renamedInOtherBB.end()) {
 | |
|       LLVM_DEBUG(dbgs() << "Vreg " << Reg
 | |
|                         << " already renamed in other BB.\n";);
 | |
|       continue;
 | |
|     }
 | |
| 
 | |
|     auto Rename = NVC.createVirtualRegister(MRI.getRegClass(Reg));
 | |
| 
 | |
|     if (VRegRenameMap.find(Reg) == VRegRenameMap.end()) {
 | |
|       LLVM_DEBUG(dbgs() << "Mapping vreg ";);
 | |
|       if (MRI.reg_begin(Reg) != MRI.reg_end()) {
 | |
|         LLVM_DEBUG(auto foo = &*MRI.reg_begin(Reg); foo->dump(););
 | |
|       } else {
 | |
|         LLVM_DEBUG(dbgs() << Reg;);
 | |
|       }
 | |
|       LLVM_DEBUG(dbgs() << " to ";);
 | |
|       if (MRI.reg_begin(Rename) != MRI.reg_end()) {
 | |
|         LLVM_DEBUG(auto foo = &*MRI.reg_begin(Rename); foo->dump(););
 | |
|       } else {
 | |
|         LLVM_DEBUG(dbgs() << Rename;);
 | |
|       }
 | |
|       LLVM_DEBUG(dbgs() << "\n";);
 | |
| 
 | |
|       VRegRenameMap.insert(std::pair<unsigned, unsigned>(Reg, Rename));
 | |
|     }
 | |
|   }
 | |
| 
 | |
|   return VRegRenameMap;
 | |
| }
 | |
| 
 | |
| static bool doVRegRenaming(std::vector<unsigned> &RenamedInOtherBB,
 | |
|                            const std::map<unsigned, unsigned> &VRegRenameMap,
 | |
|                            MachineRegisterInfo &MRI) {
 | |
|   bool Changed = false;
 | |
|   for (auto I = VRegRenameMap.begin(), E = VRegRenameMap.end(); I != E; ++I) {
 | |
| 
 | |
|     auto VReg = I->first;
 | |
|     auto Rename = I->second;
 | |
| 
 | |
|     RenamedInOtherBB.push_back(Rename);
 | |
| 
 | |
|     std::vector<MachineOperand *> RenameMOs;
 | |
|     for (auto &MO : MRI.reg_operands(VReg)) {
 | |
|       RenameMOs.push_back(&MO);
 | |
|     }
 | |
| 
 | |
|     for (auto *MO : RenameMOs) {
 | |
|       Changed = true;
 | |
|       MO->setReg(Rename);
 | |
| 
 | |
|       if (!MO->isDef())
 | |
|         MO->setIsKill(false);
 | |
|     }
 | |
|   }
 | |
| 
 | |
|   return Changed;
 | |
| }
 | |
| 
 | |
| static bool doDefKillClear(MachineBasicBlock *MBB) {
 | |
|   bool Changed = false;
 | |
| 
 | |
|   for (auto &MI : *MBB) {
 | |
|     for (auto &MO : MI.operands()) {
 | |
|       if (!MO.isReg())
 | |
|         continue;
 | |
|       if (!MO.isDef() && MO.isKill()) {
 | |
|         Changed = true;
 | |
|         MO.setIsKill(false);
 | |
|       }
 | |
| 
 | |
|       if (MO.isDef() && MO.isDead()) {
 | |
|         Changed = true;
 | |
|         MO.setIsDead(false);
 | |
|       }
 | |
|     }
 | |
|   }
 | |
| 
 | |
|   return Changed;
 | |
| }
 | |
| 
 | |
| static bool runOnBasicBlock(MachineBasicBlock *MBB,
 | |
|                             std::vector<StringRef> &bbNames,
 | |
|                             std::vector<unsigned> &renamedInOtherBB,
 | |
|                             unsigned &basicBlockNum, unsigned &VRegGapIndex,
 | |
|                             NamedVRegCursor &NVC) {
 | |
| 
 | |
|   if (CanonicalizeBasicBlockNumber != ~0U) {
 | |
|     if (CanonicalizeBasicBlockNumber != basicBlockNum++)
 | |
|       return false;
 | |
|     LLVM_DEBUG(dbgs() << "\n Canonicalizing BasicBlock " << MBB->getName()
 | |
|                       << "\n";);
 | |
|   }
 | |
| 
 | |
|   if (llvm::find(bbNames, MBB->getName()) != bbNames.end()) {
 | |
|     LLVM_DEBUG({
 | |
|       dbgs() << "Found potentially duplicate BasicBlocks: " << MBB->getName()
 | |
|              << "\n";
 | |
|     });
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   LLVM_DEBUG({
 | |
|     dbgs() << "\n\n  NEW BASIC BLOCK: " << MBB->getName() << "  \n\n";
 | |
|     dbgs() << "\n\n================================================\n\n";
 | |
|   });
 | |
| 
 | |
|   bool Changed = false;
 | |
|   MachineFunction &MF = *MBB->getParent();
 | |
|   MachineRegisterInfo &MRI = MF.getRegInfo();
 | |
| 
 | |
|   bbNames.push_back(MBB->getName());
 | |
|   LLVM_DEBUG(dbgs() << "\n\n NEW BASIC BLOCK: " << MBB->getName() << "\n\n";);
 | |
| 
 | |
|   LLVM_DEBUG(dbgs() << "MBB Before Canonical Copy Propagation:\n";
 | |
|              MBB->dump(););
 | |
|   Changed |= propagateLocalCopies(MBB);
 | |
|   LLVM_DEBUG(dbgs() << "MBB After Canonical Copy Propagation:\n"; MBB->dump(););
 | |
| 
 | |
|   LLVM_DEBUG(dbgs() << "MBB Before Scheduling:\n"; MBB->dump(););
 | |
|   unsigned IdempotentInstCount = 0;
 | |
|   Changed |= rescheduleCanonically(IdempotentInstCount, MBB);
 | |
|   LLVM_DEBUG(dbgs() << "MBB After Scheduling:\n"; MBB->dump(););
 | |
| 
 | |
|   std::vector<MachineInstr *> Candidates = populateCandidates(MBB);
 | |
|   std::vector<MachineInstr *> VisitedMIs;
 | |
|   llvm::copy(Candidates, std::back_inserter(VisitedMIs));
 | |
| 
 | |
|   std::vector<TypedVReg> VRegs;
 | |
|   for (auto candidate : Candidates) {
 | |
|     VRegs.push_back(TypedVReg(RSE_NewCandidate));
 | |
| 
 | |
|     std::queue<TypedVReg> RegQueue;
 | |
| 
 | |
|     // Here we walk the vreg operands of a non-root node along our walk.
 | |
|     // The root nodes are the original candidates (stores normally).
 | |
|     // These are normally not the root nodes (except for the case of copies to
 | |
|     // physical registers).
 | |
|     for (unsigned i = 1; i < candidate->getNumOperands(); i++) {
 | |
|       if (candidate->mayStore() || candidate->isBranch())
 | |
|         break;
 | |
| 
 | |
|       MachineOperand &MO = candidate->getOperand(i);
 | |
|       if (!(MO.isReg() && TargetRegisterInfo::isVirtualRegister(MO.getReg())))
 | |
|         continue;
 | |
| 
 | |
|       LLVM_DEBUG(dbgs() << "Enqueue register"; MO.dump(); dbgs() << "\n";);
 | |
|       RegQueue.push(TypedVReg(MO.getReg()));
 | |
|     }
 | |
| 
 | |
|     // Here we walk the root candidates. We start from the 0th operand because
 | |
|     // the root is normally a store to a vreg.
 | |
|     for (unsigned i = 0; i < candidate->getNumOperands(); i++) {
 | |
| 
 | |
|       if (!candidate->mayStore() && !candidate->isBranch())
 | |
|         break;
 | |
| 
 | |
|       MachineOperand &MO = candidate->getOperand(i);
 | |
| 
 | |
|       // TODO: Do we want to only add vregs here?
 | |
|       if (!MO.isReg() && !MO.isFI())
 | |
|         continue;
 | |
| 
 | |
|       LLVM_DEBUG(dbgs() << "Enqueue Reg/FI"; MO.dump(); dbgs() << "\n";);
 | |
| 
 | |
|       RegQueue.push(MO.isReg() ? TypedVReg(MO.getReg())
 | |
|                                : TypedVReg(RSE_FrameIndex));
 | |
|     }
 | |
| 
 | |
|     doCandidateWalk(VRegs, RegQueue, VisitedMIs, MBB);
 | |
|   }
 | |
| 
 | |
|   // If we have populated no vregs to rename then bail.
 | |
|   // The rest of this function does the vreg remaping.
 | |
|   if (VRegs.size() == 0)
 | |
|     return Changed;
 | |
| 
 | |
|   auto VRegRenameMap = GetVRegRenameMap(VRegs, renamedInOtherBB, MRI, NVC);
 | |
|   Changed |= doVRegRenaming(renamedInOtherBB, VRegRenameMap, MRI);
 | |
| 
 | |
|   // Here we renumber the def vregs for the idempotent instructions from the top
 | |
|   // of the MachineBasicBlock so that they are named in the order that we sorted
 | |
|   // them alphabetically. Eventually we wont need SkipVRegs because we will use
 | |
|   // named vregs instead.
 | |
|   NVC.SkipVRegs();
 | |
| 
 | |
|   auto MII = MBB->begin();
 | |
|   for (unsigned i = 0; i < IdempotentInstCount && MII != MBB->end(); ++i) {
 | |
|     MachineInstr &MI = *MII++;
 | |
|     Changed = true;
 | |
|     unsigned vRegToRename = MI.getOperand(0).getReg();
 | |
|     auto Rename = NVC.createVirtualRegister(MRI.getRegClass(vRegToRename));
 | |
| 
 | |
|     std::vector<MachineOperand *> RenameMOs;
 | |
|     for (auto &MO : MRI.reg_operands(vRegToRename)) {
 | |
|       RenameMOs.push_back(&MO);
 | |
|     }
 | |
| 
 | |
|     for (auto *MO : RenameMOs) {
 | |
|       MO->setReg(Rename);
 | |
|     }
 | |
|   }
 | |
| 
 | |
|   Changed |= doDefKillClear(MBB);
 | |
| 
 | |
|   LLVM_DEBUG(dbgs() << "Updated MachineBasicBlock:\n"; MBB->dump();
 | |
|              dbgs() << "\n";);
 | |
|   LLVM_DEBUG(
 | |
|       dbgs() << "\n\n================================================\n\n");
 | |
|   return Changed;
 | |
| }
 | |
| 
 | |
| bool MIRCanonicalizer::runOnMachineFunction(MachineFunction &MF) {
 | |
| 
 | |
|   static unsigned functionNum = 0;
 | |
|   if (CanonicalizeFunctionNumber != ~0U) {
 | |
|     if (CanonicalizeFunctionNumber != functionNum++)
 | |
|       return false;
 | |
|     LLVM_DEBUG(dbgs() << "\n Canonicalizing Function " << MF.getName()
 | |
|                       << "\n";);
 | |
|   }
 | |
| 
 | |
|   // we need a valid vreg to create a vreg type for skipping all those
 | |
|   // stray vreg numbers so reach alignment/canonical vreg values.
 | |
|   std::vector<MachineBasicBlock *> RPOList = GetRPOList(MF);
 | |
| 
 | |
|   LLVM_DEBUG(
 | |
|       dbgs() << "\n\n  NEW MACHINE FUNCTION: " << MF.getName() << "  \n\n";
 | |
|       dbgs() << "\n\n================================================\n\n";
 | |
|       dbgs() << "Total Basic Blocks: " << RPOList.size() << "\n";
 | |
|       for (auto MBB
 | |
|            : RPOList) { dbgs() << MBB->getName() << "\n"; } dbgs()
 | |
|       << "\n\n================================================\n\n";);
 | |
| 
 | |
|   std::vector<StringRef> BBNames;
 | |
|   std::vector<unsigned> RenamedInOtherBB;
 | |
| 
 | |
|   unsigned GapIdx = 0;
 | |
|   unsigned BBNum = 0;
 | |
| 
 | |
|   bool Changed = false;
 | |
| 
 | |
|   MachineRegisterInfo &MRI = MF.getRegInfo();
 | |
|   NamedVRegCursor NVC(MRI);
 | |
|   for (auto MBB : RPOList)
 | |
|     Changed |=
 | |
|         runOnBasicBlock(MBB, BBNames, RenamedInOtherBB, BBNum, GapIdx, NVC);
 | |
| 
 | |
|   return Changed;
 | |
| }
 |