MIRParser: Rewrite register info initialization; mostly NFC

This changes MachineRegisterInfo to be initializes after parsing all
instructions. This is in preparation for upcoming commits that allow the
register class specification on the operand or deduce them from the
MCInstrDesc.

This commit removes the unused feature of having nonsequential register
numbers. This was confusing anyway as the vreg numbers would be
different after parsing when you had "holes" in your numbering.

This patch also introduces the concept of an incomplete virtual
register. An incomplete virtual register may be used during .mir parsing
to construct MachineOperands without knowing the exact register class
(or register bank) yet.

NFC except for some error messages.

Differential Revision: https://reviews.llvm.org/D22397

llvm-svn: 283848

1 files changed, 65 insertions, 43 deletions

diff --git a/llvm/lib/CodeGen/MIRParser/MIParser.cpp b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
index 78f9e907295..98bc8a1c69f 100644
--- a/llvm/lib/CodeGen/MIRParser/MIParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
@@ -44,6 +44,17 @@ PerFunctionMIParsingState::PerFunctionMIParsingState(MachineFunction &MF,
   : MF(MF), SM(&SM), IRSlots(IRSlots) {
 }
 
+VRegInfo &PerFunctionMIParsingState::getVRegInfo(unsigned Num) {
+  auto I = VRegInfos.insert(std::make_pair(Num, nullptr));
+  if (I.second) {
+    MachineRegisterInfo &MRI = MF.getRegInfo();
+    VRegInfo *Info = new (Allocator) VRegInfo;
+    Info->VReg = MRI.createIncompleteVirtualRegister();
+    I.first->second = Info;
+  }
+  return *I.first->second;
+}
+
 namespace {
 
 /// A wrapper struct around the 'MachineOperand' struct that includes a source
@@ -68,7 +79,7 @@ class MIParser {
   SMDiagnostic &Error;
   StringRef Source, CurrentSource;
   MIToken Token;
-  const PerFunctionMIParsingState &PFS;
+  PerFunctionMIParsingState &PFS;
   /// Maps from instruction names to op codes.
   StringMap<unsigned> Names2InstrOpCodes;
   /// Maps from register names to registers.
@@ -89,7 +100,7 @@ class MIParser {
   StringMap<unsigned> Names2BitmaskTargetFlags;
 
 public:
-  MIParser(const PerFunctionMIParsingState &PFS, SMDiagnostic &Error,
+  MIParser(PerFunctionMIParsingState &PFS, SMDiagnostic &Error,
            StringRef Source);
 
   /// \p SkipChar gives the number of characters to skip before looking
@@ -112,7 +123,7 @@ public:
   bool parse(MachineInstr *&MI);
   bool parseStandaloneMBB(MachineBasicBlock *&MBB);
   bool parseStandaloneNamedRegister(unsigned &Reg);
-  bool parseStandaloneVirtualRegister(unsigned &Reg);
+  bool parseStandaloneVirtualRegister(VRegInfo *&Info);
   bool parseStandaloneStackObject(int &FI);
   bool parseStandaloneMDNode(MDNode *&Node);
 
@@ -122,7 +133,9 @@ public:
   bool parseBasicBlockLiveins(MachineBasicBlock &MBB);
   bool parseBasicBlockSuccessors(MachineBasicBlock &MBB);
 
-  bool parseRegister(unsigned &Reg);
+  bool parseNamedRegister(unsigned &Reg);
+  bool parseVirtualRegister(VRegInfo *&Info);
+  bool parseRegister(unsigned &Reg, VRegInfo *&VRegInfo);
   bool parseRegisterFlag(unsigned &Flags);
   bool parseSubRegisterIndex(unsigned &SubReg);
   bool parseRegisterTiedDefIndex(unsigned &TiedDefIdx);
@@ -255,7 +268,7 @@ private:
 
 } // end anonymous namespace
 
-MIParser::MIParser(const PerFunctionMIParsingState &PFS, SMDiagnostic &Error,
+MIParser::MIParser(PerFunctionMIParsingState &PFS, SMDiagnostic &Error,
                    StringRef Source)
     : MF(PFS.MF), Error(Error), Source(Source), CurrentSource(Source), PFS(PFS)
 {}
@@ -438,7 +451,7 @@ bool MIParser::parseBasicBlockLiveins(MachineBasicBlock &MBB) {
     if (Token.isNot(MIToken::NamedRegister))
       return error("expected a named register");
     unsigned Reg = 0;
-    if (parseRegister(Reg))
+    if (parseNamedRegister(Reg))
       return true;
     MBB.addLiveIn(Reg);
     lex();
@@ -683,7 +696,7 @@ bool MIParser::parseStandaloneNamedRegister(unsigned &Reg) {
   lex();
   if (Token.isNot(MIToken::NamedRegister))
     return error("expected a named register");
-  if (parseRegister(Reg))
+  if (parseNamedRegister(Reg))
     return true;
   lex();
   if (Token.isNot(MIToken::Eof))
@@ -691,11 +704,11 @@ bool MIParser::parseStandaloneNamedRegister(unsigned &Reg) {
   return false;
 }
 
-bool MIParser::parseStandaloneVirtualRegister(unsigned &Reg) {
+bool MIParser::parseStandaloneVirtualRegister(VRegInfo *&Info) {
   lex();
   if (Token.isNot(MIToken::VirtualRegister))
     return error("expected a virtual register");
-  if (parseRegister(Reg))
+  if (parseVirtualRegister(Info))
     return true;
   lex();
   if (Token.isNot(MIToken::Eof))
@@ -791,33 +804,39 @@ bool MIParser::parseInstruction(unsigned &OpCode, unsigned &Flags) {
   return false;
 }
 
-bool MIParser::parseRegister(unsigned &Reg) {
+bool MIParser::parseNamedRegister(unsigned &Reg) {
+  assert(Token.is(MIToken::NamedRegister) && "Needs NamedRegister token");
+  StringRef Name = Token.stringValue();
+  if (getRegisterByName(Name, Reg))
+    return error(Twine("unknown register name '") + Name + "'");
+  return false;
+}
+
+bool MIParser::parseVirtualRegister(VRegInfo *&Info) {
+  assert(Token.is(MIToken::VirtualRegister) && "Needs VirtualRegister token");
+  unsigned ID;
+  if (getUnsigned(ID))
+    return true;
+  Info = &PFS.getVRegInfo(ID);
+  return false;
+}
+
+bool MIParser::parseRegister(unsigned &Reg, VRegInfo *&Info) {
   switch (Token.kind()) {
   case MIToken::underscore:
     Reg = 0;
-    break;
-  case MIToken::NamedRegister: {
-    StringRef Name = Token.stringValue();
-    if (getRegisterByName(Name, Reg))
-      return error(Twine("unknown register name '") + Name + "'");
-    break;
-  }
-  case MIToken::VirtualRegister: {
-    unsigned ID;
-    if (getUnsigned(ID))
+    return false;
+  case MIToken::NamedRegister:
+    return parseNamedRegister(Reg);
+  case MIToken::VirtualRegister:
+    if (parseVirtualRegister(Info))
       return true;
-    const auto RegInfo = PFS.VirtualRegisterSlots.find(ID);
-    if (RegInfo == PFS.VirtualRegisterSlots.end())
-      return error(Twine("use of undefined virtual register '%") + Twine(ID) +
-                   "'");
-    Reg = RegInfo->second;
-    break;
-  }
+    Reg = Info->VReg;
+    return false;
   // TODO: Parse other register kinds.
   default:
     llvm_unreachable("The current token should be a register");
   }
-  return false;
 }
 
 bool MIParser::parseRegisterFlag(unsigned &Flags) {
@@ -927,7 +946,6 @@ bool MIParser::assignRegisterTies(MachineInstr &MI,
 bool MIParser::parseRegisterOperand(MachineOperand &Dest,
                                     Optional<unsigned> &TiedDefIdx,
                                     bool IsDef) {
-  unsigned Reg;
   unsigned Flags = IsDef ? RegState::Define : 0;
   while (Token.isRegisterFlag()) {
     if (parseRegisterFlag(Flags))
@@ -935,7 +953,9 @@ bool MIParser::parseRegisterOperand(MachineOperand &Dest,
   }
   if (!Token.isRegister())
     return error("expected a register after register flags");
-  if (parseRegister(Reg))
+  unsigned Reg;
+  VRegInfo *RegInfo;
+  if (parseRegister(Reg, RegInfo))
     return true;
   lex();
   unsigned SubReg = 0;
@@ -984,11 +1004,13 @@ bool MIParser::parseRegisterOperand(MachineOperand &Dest,
       return error("inconsistent type for generic virtual register");
 
     MRI.setType(Reg, Ty);
-  } else if (PFS.GenericVRegs.count(Reg)) {
+  } else if (TargetRegisterInfo::isVirtualRegister(Reg)) {
     // Generic virtual registers must have a size.
     // If we end up here this means the size hasn't been specified and
     // this is bad!
-    return error("generic virtual registers must have a size");
+    if (RegInfo->Kind == VRegInfo::GENERIC ||
+        RegInfo->Kind == VRegInfo::REGBANK)
+      return error("generic virtual registers must have a size");
   }
   Dest = MachineOperand::CreateReg(
       Reg, Flags & RegState::Define, Flags & RegState::Implicit,
@@ -1305,7 +1327,7 @@ bool MIParser::parseCFIRegister(unsigned &Reg) {
   if (Token.isNot(MIToken::NamedRegister))
     return error("expected a cfi register");
   unsigned LLVMReg;
-  if (parseRegister(LLVMReg))
+  if (parseNamedRegister(LLVMReg))
     return true;
   const auto *TRI = MF.getSubtarget().getRegisterInfo();
   assert(TRI && "Expected target register info");
@@ -1540,8 +1562,8 @@ bool MIParser::parseLiveoutRegisterMaskOperand(MachineOperand &Dest) {
   while (true) {
     if (Token.isNot(MIToken::NamedRegister))
       return error("expected a named register");
-    unsigned Reg = 0;
-    if (parseRegister(Reg))
+    unsigned Reg;
+    if (parseNamedRegister(Reg))
       return true;
     lex();
     Mask[Reg / 32] |= 1U << (Reg % 32);
@@ -2166,36 +2188,36 @@ bool llvm::parseMachineBasicBlockDefinitions(PerFunctionMIParsingState &PFS,
   return MIParser(PFS, Error, Src).parseBasicBlockDefinitions(PFS.MBBSlots);
 }
 
-bool llvm::parseMachineInstructions(const PerFunctionMIParsingState &PFS,
+bool llvm::parseMachineInstructions(PerFunctionMIParsingState &PFS,
                                     StringRef Src, SMDiagnostic &Error) {
   return MIParser(PFS, Error, Src).parseBasicBlocks();
 }
 
-bool llvm::parseMBBReference(const PerFunctionMIParsingState &PFS,
+bool llvm::parseMBBReference(PerFunctionMIParsingState &PFS,
                              MachineBasicBlock *&MBB, StringRef Src,
                              SMDiagnostic &Error) {
   return MIParser(PFS, Error, Src).parseStandaloneMBB(MBB);
 }
 
-bool llvm::parseNamedRegisterReference(const PerFunctionMIParsingState &PFS,
+bool llvm::parseNamedRegisterReference(PerFunctionMIParsingState &PFS,
                                        unsigned &Reg, StringRef Src,
                                        SMDiagnostic &Error) {
   return MIParser(PFS, Error, Src).parseStandaloneNamedRegister(Reg);
 }
 
-bool llvm::parseVirtualRegisterReference(const PerFunctionMIParsingState &PFS,
-                                         unsigned &Reg, StringRef Src,
+bool llvm::parseVirtualRegisterReference(PerFunctionMIParsingState &PFS,
+                                         VRegInfo *&Info, StringRef Src,
                                          SMDiagnostic &Error) {
-  return MIParser(PFS, Error, Src).parseStandaloneVirtualRegister(Reg);
+  return MIParser(PFS, Error, Src).parseStandaloneVirtualRegister(Info);
 }
 
-bool llvm::parseStackObjectReference(const PerFunctionMIParsingState &PFS,
+bool llvm::parseStackObjectReference(PerFunctionMIParsingState &PFS,
                                      int &FI, StringRef Src,
                                      SMDiagnostic &Error) {
   return MIParser(PFS, Error, Src).parseStandaloneStackObject(FI);
 }
 
-bool llvm::parseMDNode(const PerFunctionMIParsingState &PFS,
+bool llvm::parseMDNode(PerFunctionMIParsingState &PFS,
                        MDNode *&Node, StringRef Src, SMDiagnostic &Error) {
   return MIParser(PFS, Error, Src).parseStandaloneMDNode(Node);
 }