X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FMachineRegisterInfo.cpp;h=5fb938f3400dafe23d7c7cbad1d3c5b204ebd21c;hb=3e2d76c946ba753c2b11af192a52e25b6f9b46ff;hp=b41a1e748cc3b6329db0899939fa420c75e553c2;hpb=a91a7d594ff1e1503731ca92f72e627bdfd18f3f;p=oota-llvm.git

diff --git a/lib/CodeGen/MachineRegisterInfo.cpp b/lib/CodeGen/MachineRegisterInfo.cpp
index b41a1e748cc..5fb938f3400 100644
--- a/lib/CodeGen/MachineRegisterInfo.cpp
+++ b/lib/CodeGen/MachineRegisterInfo.cpp
@@ -12,36 +12,185 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetMachine.h"
 using namespace llvm;
 
-MachineRegisterInfo::MachineRegisterInfo(const MRegisterInfo &MRI) {
+MachineRegisterInfo::MachineRegisterInfo(const TargetRegisterInfo &TRI)
+  : TRI(&TRI), IsSSA(true), TracksLiveness(true) {
   VRegInfo.reserve(256);
-  UsedPhysRegs.resize(MRI.getNumRegs());
-  
+  RegAllocHints.reserve(256);
+  UsedPhysRegs.resize(TRI.getNumRegs());
+  UsedPhysRegMask.resize(TRI.getNumRegs());
+
   // Create the physreg use/def lists.
-  PhysRegUseDefLists = new MachineOperand*[MRI.getNumRegs()];
-  memset(PhysRegUseDefLists, 0, sizeof(MachineOperand*)*MRI.getNumRegs());
+  PhysRegUseDefLists = new MachineOperand*[TRI.getNumRegs()];
+  memset(PhysRegUseDefLists, 0, sizeof(MachineOperand*)*TRI.getNumRegs());
 }
 
 MachineRegisterInfo::~MachineRegisterInfo() {
 #ifndef NDEBUG
-  for (unsigned i = 0, e = VRegInfo.size(); i != e; ++i)
-    assert(VRegInfo[i].second == 0 && "Vreg use list non-empty still?");
+  clearVirtRegs();
+  for (unsigned i = 0, e = UsedPhysRegs.size(); i != e; ++i)
+    assert(!PhysRegUseDefLists[i] &&
+           "PhysRegUseDefLists has entries after all instructions are deleted");
 #endif
   delete [] PhysRegUseDefLists;
 }
 
-/// HandleVRegListReallocation - We just added a virtual register to the
-/// VRegInfo info list and it reallocated.  Update the use/def lists info
-/// pointers.
-void MachineRegisterInfo::HandleVRegListReallocation() {
-  // The back pointers for the vreg lists point into the previous vector.
-  // Update them to point to their correct slots.
-  for (unsigned i = 0, e = VRegInfo.size(); i != e; ++i) {
-    MachineOperand *List = VRegInfo[i].second;
-    if (!List) continue;
-    // Update the back-pointer to be accurate once more.
-    List->Contents.Reg.Prev = &VRegInfo[i].second;
+/// setRegClass - Set the register class of the specified virtual register.
+///
+void
+MachineRegisterInfo::setRegClass(unsigned Reg, const TargetRegisterClass *RC) {
+  VRegInfo[Reg].first = RC;
+}
+
+const TargetRegisterClass *
+MachineRegisterInfo::constrainRegClass(unsigned Reg,
+                                       const TargetRegisterClass *RC,
+                                       unsigned MinNumRegs) {
+  const TargetRegisterClass *OldRC = getRegClass(Reg);
+  if (OldRC == RC)
+    return RC;
+  const TargetRegisterClass *NewRC = TRI->getCommonSubClass(OldRC, RC);
+  if (!NewRC || NewRC == OldRC)
+    return NewRC;
+  if (NewRC->getNumRegs() < MinNumRegs)
+    return 0;
+  setRegClass(Reg, NewRC);
+  return NewRC;
+}
+
+bool
+MachineRegisterInfo::recomputeRegClass(unsigned Reg, const TargetMachine &TM) {
+  const TargetInstrInfo *TII = TM.getInstrInfo();
+  const TargetRegisterClass *OldRC = getRegClass(Reg);
+  const TargetRegisterClass *NewRC = TRI->getLargestLegalSuperClass(OldRC);
+
+  // Stop early if there is no room to grow.
+  if (NewRC == OldRC)
+    return false;
+
+  // Accumulate constraints from all uses.
+  for (reg_nodbg_iterator I = reg_nodbg_begin(Reg), E = reg_nodbg_end(); I != E;
+       ++I) {
+    const TargetRegisterClass *OpRC =
+      I->getRegClassConstraint(I.getOperandNo(), TII, TRI);
+    if (unsigned SubIdx = I.getOperand().getSubReg()) {
+      if (OpRC)
+        NewRC = TRI->getMatchingSuperRegClass(NewRC, OpRC, SubIdx);
+      else
+        NewRC = TRI->getSubClassWithSubReg(NewRC, SubIdx);
+    } else if (OpRC)
+      NewRC = TRI->getCommonSubClass(NewRC, OpRC);
+    if (!NewRC || NewRC == OldRC)
+      return false;
+  }
+  setRegClass(Reg, NewRC);
+  return true;
+}
+
+/// createVirtualRegister - Create and return a new virtual register in the
+/// function with the specified register class.
+///
+unsigned
+MachineRegisterInfo::createVirtualRegister(const TargetRegisterClass *RegClass){
+  assert(RegClass && "Cannot create register without RegClass!");
+  assert(RegClass->isAllocatable() &&
+         "Virtual register RegClass must be allocatable.");
+
+  // New virtual register number.
+  unsigned Reg = TargetRegisterInfo::index2VirtReg(getNumVirtRegs());
+  VRegInfo.grow(Reg);
+  VRegInfo[Reg].first = RegClass;
+  RegAllocHints.grow(Reg);
+  return Reg;
+}
+
+/// clearVirtRegs - Remove all virtual registers (after physreg assignment).
+void MachineRegisterInfo::clearVirtRegs() {
+#ifndef NDEBUG
+  for (unsigned i = 0, e = getNumVirtRegs(); i != e; ++i)
+    assert(VRegInfo[TargetRegisterInfo::index2VirtReg(i)].second == 0 &&
+           "Vreg use list non-empty still?");
+#endif
+  VRegInfo.clear();
+}
+
+/// Add MO to the linked list of operands for its register.
+void MachineRegisterInfo::addRegOperandToUseList(MachineOperand *MO) {
+  assert(!MO->isOnRegUseList() && "Already on list");
+  MachineOperand *&HeadRef = getRegUseDefListHead(MO->getReg());
+  MachineOperand *const Head = HeadRef;
+
+  // Head points to the first list element.
+  // Next is NULL on the last list element.
+  // Prev pointers are circular, so Head->Prev == Last.
+
+  // Head is NULL for an empty list.
+  if (!Head) {
+    MO->Contents.Reg.Prev = MO;
+    MO->Contents.Reg.Next = 0;
+    HeadRef = MO;
+    return;
+  }
+  assert(MO->getReg() == Head->getReg() && "Different regs on the same list!");
+
+  // Insert MO between Last and Head in the circular Prev chain.
+  MachineOperand *Last = Head->Contents.Reg.Prev;
+  assert(Last && "Inconsistent use list");
+  assert(MO->getReg() == Last->getReg() && "Different regs on the same list!");
+  Head->Contents.Reg.Prev = MO;
+  MO->Contents.Reg.Prev = Last;
+
+  // Def operands always precede uses. This allows def_iterator to stop early.
+  // Insert def operands at the front, and use operands at the back.
+  if (MO->isDef()) {
+    // Insert def at the front.
+    MO->Contents.Reg.Next = Head;
+    HeadRef = MO;
+  } else {
+    // Insert use at the end.
+    MO->Contents.Reg.Next = 0;
+    Last->Contents.Reg.Next = MO;
+  }
+}
+
+/// Remove MO from its use-def list.
+void MachineRegisterInfo::removeRegOperandFromUseList(MachineOperand *MO) {
+  assert(MO->isOnRegUseList() && "Operand not on use list");
+  MachineOperand *&HeadRef = getRegUseDefListHead(MO->getReg());
+  MachineOperand *const Head = HeadRef;
+  assert(Head && "List already empty");
+
+  // Unlink this from the doubly linked list of operands.
+  MachineOperand *Next = MO->Contents.Reg.Next;
+  MachineOperand *Prev = MO->Contents.Reg.Prev;
+
+  // Prev links are circular, next link is NULL instead of looping back to Head.
+  if (MO == Head)
+    HeadRef = Next;
+  else
+    Prev->Contents.Reg.Next = Next;
+
+  (Next ? Next : Head)->Contents.Reg.Prev = Prev;
+
+  MO->Contents.Reg.Prev = 0;
+  MO->Contents.Reg.Next = 0;
+}
+
+/// replaceRegWith - Replace all instances of FromReg with ToReg in the
+/// machine function.  This is like llvm-level X->replaceAllUsesWith(Y),
+/// except that it also changes any definitions of the register as well.
+void MachineRegisterInfo::replaceRegWith(unsigned FromReg, unsigned ToReg) {
+  assert(FromReg != ToReg && "Cannot replace a reg with itself");
+
+  // TODO: This could be more efficient by bulk changing the operands.
+  for (reg_iterator I = reg_begin(FromReg), E = reg_end(); I != E; ) {
+    MachineOperand &O = I.getOperand();
+    ++I;
+    O.setReg(ToReg);
   }
 }
 
@@ -50,12 +199,129 @@ void MachineRegisterInfo::HandleVRegListReallocation() {
 /// register or null if none is found.  This assumes that the code is in SSA
 /// form, so there should only be one definition.
 MachineInstr *MachineRegisterInfo::getVRegDef(unsigned Reg) const {
-  assert(Reg-MRegisterInfo::FirstVirtualRegister < VRegInfo.size() &&
-         "Invalid vreg!");
-  for (reg_iterator I = reg_begin(Reg), E = reg_end(); I != E; ++I) {
-    // Since we are in SSA form, we can stop at the first definition.
-    if (I->isDef())
-      return I->getParent();
-  }
+  // Since we are in SSA form, we can use the first definition.
+  def_iterator I = def_begin(Reg);
+  assert((I.atEnd() || llvm::next(I) == def_end()) &&
+         "getVRegDef assumes a single definition or no definition");
+  return !I.atEnd() ? &*I : 0;
+}
+
+/// getUniqueVRegDef - Return the unique machine instr that defines the
+/// specified virtual register or null if none is found.  If there are
+/// multiple definitions or no definition, return null.
+MachineInstr *MachineRegisterInfo::getUniqueVRegDef(unsigned Reg) const {
+  if (def_empty(Reg)) return 0;
+  def_iterator I = def_begin(Reg);
+  if (llvm::next(I) != def_end())
+    return 0;
+  return &*I;
+}
+
+bool MachineRegisterInfo::hasOneNonDBGUse(unsigned RegNo) const {
+  use_nodbg_iterator UI = use_nodbg_begin(RegNo);
+  if (UI == use_nodbg_end())
+    return false;
+  return ++UI == use_nodbg_end();
+}
+
+/// clearKillFlags - Iterate over all the uses of the given register and
+/// clear the kill flag from the MachineOperand. This function is used by
+/// optimization passes which extend register lifetimes and need only
+/// preserve conservative kill flag information.
+void MachineRegisterInfo::clearKillFlags(unsigned Reg) const {
+  for (use_iterator UI = use_begin(Reg), UE = use_end(); UI != UE; ++UI)
+    UI.getOperand().setIsKill(false);
+}
+
+bool MachineRegisterInfo::isLiveIn(unsigned Reg) const {
+  for (livein_iterator I = livein_begin(), E = livein_end(); I != E; ++I)
+    if (I->first == Reg || I->second == Reg)
+      return true;
+  return false;
+}
+
+bool MachineRegisterInfo::isLiveOut(unsigned Reg) const {
+  for (liveout_iterator I = liveout_begin(), E = liveout_end(); I != E; ++I)
+    if (*I == Reg)
+      return true;
+  return false;
+}
+
+/// getLiveInPhysReg - If VReg is a live-in virtual register, return the
+/// corresponding live-in physical register.
+unsigned MachineRegisterInfo::getLiveInPhysReg(unsigned VReg) const {
+  for (livein_iterator I = livein_begin(), E = livein_end(); I != E; ++I)
+    if (I->second == VReg)
+      return I->first;
+  return 0;
+}
+
+/// getLiveInVirtReg - If PReg is a live-in physical register, return the
+/// corresponding live-in physical register.
+unsigned MachineRegisterInfo::getLiveInVirtReg(unsigned PReg) const {
+  for (livein_iterator I = livein_begin(), E = livein_end(); I != E; ++I)
+    if (I->first == PReg)
+      return I->second;
   return 0;
 }
+
+/// EmitLiveInCopies - Emit copies to initialize livein virtual registers
+/// into the given entry block.
+void
+MachineRegisterInfo::EmitLiveInCopies(MachineBasicBlock *EntryMBB,
+                                      const TargetRegisterInfo &TRI,
+                                      const TargetInstrInfo &TII) {
+  // Emit the copies into the top of the block.
+  for (unsigned i = 0, e = LiveIns.size(); i != e; ++i)
+    if (LiveIns[i].second) {
+      if (use_empty(LiveIns[i].second)) {
+        // The livein has no uses. Drop it.
+        //
+        // It would be preferable to have isel avoid creating live-in
+        // records for unused arguments in the first place, but it's
+        // complicated by the debug info code for arguments.
+        LiveIns.erase(LiveIns.begin() + i);
+        --i; --e;
+      } else {
+        // Emit a copy.
+        BuildMI(*EntryMBB, EntryMBB->begin(), DebugLoc(),
+                TII.get(TargetOpcode::COPY), LiveIns[i].second)
+          .addReg(LiveIns[i].first);
+
+        // Add the register to the entry block live-in set.
+        EntryMBB->addLiveIn(LiveIns[i].first);
+      }
+    } else {
+      // Add the register to the entry block live-in set.
+      EntryMBB->addLiveIn(LiveIns[i].first);
+    }
+}
+
+#ifndef NDEBUG
+void MachineRegisterInfo::dumpUses(unsigned Reg) const {
+  for (use_iterator I = use_begin(Reg), E = use_end(); I != E; ++I)
+    I.getOperand().getParent()->dump();
+}
+#endif
+
+void MachineRegisterInfo::freezeReservedRegs(const MachineFunction &MF) {
+  ReservedRegs = TRI->getReservedRegs(MF);
+}
+
+bool MachineRegisterInfo::isConstantPhysReg(unsigned PhysReg,
+                                            const MachineFunction &MF) const {
+  assert(TargetRegisterInfo::isPhysicalRegister(PhysReg));
+
+  // Check if any overlapping register is modified.
+  for (MCRegAliasIterator AI(PhysReg, TRI, true); AI.isValid(); ++AI)
+    if (!def_empty(*AI))
+      return false;
+
+  // Check if any overlapping register is allocatable so it may be used later.
+  if (AllocatableRegs.empty())
+    AllocatableRegs = TRI->getAllocatableSet(MF);
+  for (MCRegAliasIterator AI(PhysReg, TRI, true); AI.isValid(); ++AI)
+    if (AllocatableRegs.test(*AI))
+      return false;
+  return true;
+}