Move lib/Codegen/RegAlloc into lib/Target/Sparc, as it is sparc specific

llvm-svn: 10728

1 files changed, 416 insertions, 0 deletions

diff --git a/llvm/lib/Target/Sparc/RegAlloc/LiveRangeInfo.cpp b/llvm/lib/Target/Sparc/RegAlloc/LiveRangeInfo.cpp
new file mode 100644
index 00000000000..380680448d3
--- /dev/null
+++ b/llvm/lib/Target/Sparc/RegAlloc/LiveRangeInfo.cpp
@@ -0,0 +1,416 @@
+//===-- LiveRangeInfo.cpp -------------------------------------------------===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+// 
+//  Live range construction for coloring-based register allocation for LLVM.
+// 
+//===----------------------------------------------------------------------===//
+
+#include "IGNode.h"
+#include "LiveRangeInfo.h"
+#include "RegAllocCommon.h"
+#include "RegClass.h"
+#include "llvm/Function.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetRegInfo.h"
+#include "Support/SetOperations.h"
+
+namespace llvm {
+
+unsigned LiveRange::getRegClassID() const { return getRegClass()->getID(); }
+
+LiveRangeInfo::LiveRangeInfo(const Function *F, const TargetMachine &tm,
+			     std::vector<RegClass *> &RCL)
+  : Meth(F), TM(tm), RegClassList(RCL), MRI(tm.getRegInfo()) { }
+
+
+LiveRangeInfo::~LiveRangeInfo() {
+  for (LiveRangeMapType::iterator MI = LiveRangeMap.begin(); 
+       MI != LiveRangeMap.end(); ++MI) {  
+
+    if (MI->first && MI->second) {
+      LiveRange *LR = MI->second;
+
+      // we need to be careful in deleting LiveRanges in LiveRangeMap
+      // since two/more Values in the live range map can point to the same
+      // live range. We have to make the other entries NULL when we delete
+      // a live range.
+
+      for (LiveRange::iterator LI = LR->begin(); LI != LR->end(); ++LI)
+        LiveRangeMap[*LI] = 0;
+      
+      delete LR;
+    }
+  }
+}
+
+
+//---------------------------------------------------------------------------
+// union two live ranges into one. The 2nd LR is deleted. Used for coalescing.
+// Note: the caller must make sure that L1 and L2 are distinct and both
+// LRs don't have suggested colors
+//---------------------------------------------------------------------------
+
+void LiveRangeInfo::unionAndUpdateLRs(LiveRange *L1, LiveRange *L2) {
+  assert(L1 != L2 && (!L1->hasSuggestedColor() || !L2->hasSuggestedColor()));
+  assert(! (L1->hasColor() && L2->hasColor()) ||
+         L1->getColor() == L2->getColor());
+
+  set_union(*L1, *L2);                   // add elements of L2 to L1
+
+  for(ValueSet::iterator L2It = L2->begin(); L2It != L2->end(); ++L2It) {
+    //assert(( L1->getTypeID() == L2->getTypeID()) && "Merge:Different types");
+
+    L1->insert(*L2It);                  // add the var in L2 to L1
+    LiveRangeMap[*L2It] = L1;           // now the elements in L2 should map 
+                                        //to L1    
+  }
+  
+  // set call interference for L1 from L2
+  if (L2->isCallInterference())
+    L1->setCallInterference();
+  
+  // add the spill costs
+  L1->addSpillCost(L2->getSpillCost());
+
+  // If L2 has a color, give L1 that color.  Note that L1 may have had the same
+  // color or none, but would not have a different color as asserted above.
+  if (L2->hasColor())
+    L1->setColor(L2->getColor());
+
+  // Similarly, if LROfUse(L2) has a suggested color, the new range
+  // must have the same color.
+  if (L2->hasSuggestedColor())
+    L1->setSuggestedColor(L2->getSuggestedColor());
+  
+  delete L2;                        // delete L2 as it is no longer needed
+}
+
+
+//---------------------------------------------------------------------------
+// Method for creating a single live range for a definition.
+// The definition must be represented by a virtual register (a Value).
+// Note: this function does *not* check that no live range exists for def.
+//---------------------------------------------------------------------------
+
+LiveRange*
+LiveRangeInfo::createNewLiveRange(const Value* Def, bool isCC /* = false*/)
+{  
+  LiveRange* DefRange = new LiveRange();  // Create a new live range,
+  DefRange->insert(Def);                  // add Def to it,
+  LiveRangeMap[Def] = DefRange;           // and update the map.
+
+  // set the register class of the new live range
+  DefRange->setRegClass(RegClassList[MRI.getRegClassIDOfType(Def->getType(),
+                                                             isCC)]);
+
+  if (DEBUG_RA >= RA_DEBUG_LiveRanges) {
+    std::cerr << "  Creating a LR for def ";
+    if (isCC) std::cerr << " (CC Register!)";
+    std::cerr << " : " << RAV(Def) << "\n";
+  }
+  return DefRange;
+}
+
+
+LiveRange*
+LiveRangeInfo::createOrAddToLiveRange(const Value* Def, bool isCC /* = false*/)
+{  
+  LiveRange *DefRange = LiveRangeMap[Def];
+
+  // check if the LR is already there (because of multiple defs)
+  if (!DefRange) { 
+    DefRange = createNewLiveRange(Def, isCC);
+  } else {                          // live range already exists
+    DefRange->insert(Def);          // add the operand to the range
+    LiveRangeMap[Def] = DefRange;   // make operand point to merged set
+    if (DEBUG_RA >= RA_DEBUG_LiveRanges)
+      std::cerr << "   Added to existing LR for def: " << RAV(Def) << "\n";
+  }
+  return DefRange;
+}
+
+
+//---------------------------------------------------------------------------
+// Method for constructing all live ranges in a function. It creates live 
+// ranges for all values defined in the instruction stream. Also, it
+// creates live ranges for all incoming arguments of the function.
+//---------------------------------------------------------------------------
+void LiveRangeInfo::constructLiveRanges() {  
+
+  if (DEBUG_RA >= RA_DEBUG_LiveRanges) 
+    std::cerr << "Constructing Live Ranges ...\n";
+
+  // first find the live ranges for all incoming args of the function since
+  // those LRs start from the start of the function
+  for (Function::const_aiterator AI = Meth->abegin(); AI != Meth->aend(); ++AI)
+    createNewLiveRange(AI, /*isCC*/ false);
+
+  // Now suggest hardware registers for these function args 
+  MRI.suggestRegs4MethodArgs(Meth, *this);
+
+  // Now create LRs for machine instructions.  A new LR will be created 
+  // only for defs in the machine instr since, we assume that all Values are
+  // defined before they are used. However, there can be multiple defs for
+  // the same Value in machine instructions.
+  // 
+  // Also, find CALL and RETURN instructions, which need extra work.
+  //
+  MachineFunction &MF = MachineFunction::get(Meth);
+  for (MachineFunction::iterator BBI = MF.begin(); BBI != MF.end(); ++BBI) {
+    MachineBasicBlock &MBB = *BBI;
+
+    // iterate over all the machine instructions in BB
+    for(MachineBasicBlock::iterator MInstIterator = MBB.begin();
+        MInstIterator != MBB.end(); ++MInstIterator) {  
+      MachineInstr *MInst = *MInstIterator; 
+
+      // If the machine instruction is a  call/return instruction, add it to
+      // CallRetInstrList for processing its args, ret value, and ret addr.
+      // 
+      if(TM.getInstrInfo().isReturn(MInst->getOpCode()) ||
+	 TM.getInstrInfo().isCall(MInst->getOpCode()))
+	CallRetInstrList.push_back(MInst); 
+ 
+      // iterate over explicit MI operands and create a new LR
+      // for each operand that is defined by the instruction
+      for (MachineInstr::val_op_iterator OpI = MInst->begin(),
+             OpE = MInst->end(); OpI != OpE; ++OpI)
+	if (OpI.isDef()) {     
+	  const Value *Def = *OpI;
+          bool isCC = (OpI.getMachineOperand().getType()
+                       == MachineOperand::MO_CCRegister);
+          LiveRange* LR = createOrAddToLiveRange(Def, isCC);
+
+          // If the operand has a pre-assigned register,
+          // set it directly in the LiveRange
+          if (OpI.getMachineOperand().hasAllocatedReg()) {
+            unsigned getClassId;
+            LR->setColor(MRI.getClassRegNum(
+                                OpI.getMachineOperand().getAllocatedRegNum(),
+                                getClassId));
+          }
+	}
+
+      // iterate over implicit MI operands and create a new LR
+      // for each operand that is defined by the instruction
+      for (unsigned i = 0; i < MInst->getNumImplicitRefs(); ++i) 
+	if (MInst->getImplicitOp(i).isDef()) {
+	  const Value *Def = MInst->getImplicitRef(i);
+          LiveRange* LR = createOrAddToLiveRange(Def, /*isCC*/ false);
+
+          // If the implicit operand has a pre-assigned register,
+          // set it directly in the LiveRange
+          if (MInst->getImplicitOp(i).hasAllocatedReg()) {
+            unsigned getClassId;
+            LR->setColor(MRI.getClassRegNum(
+                                MInst->getImplicitOp(i).getAllocatedRegNum(),
+                                getClassId));
+          }
+	}
+
+    } // for all machine instructions in the BB
+  } // for all BBs in function
+
+  // Now we have to suggest clors for call and return arg live ranges.
+  // Also, if there are implicit defs (e.g., retun value of a call inst)
+  // they must be added to the live range list
+  // 
+  suggestRegs4CallRets();
+
+  if( DEBUG_RA >= RA_DEBUG_LiveRanges) 
+    std::cerr << "Initial Live Ranges constructed!\n";
+}
+
+
+//---------------------------------------------------------------------------
+// If some live ranges must be colored with specific hardware registers
+// (e.g., for outgoing call args), suggesting of colors for such live
+// ranges is done using target specific function. Those functions are called
+// from this function. The target specific methods must:
+//    1) suggest colors for call and return args. 
+//    2) create new LRs for implicit defs in machine instructions
+//---------------------------------------------------------------------------
+void LiveRangeInfo::suggestRegs4CallRets() {
+  std::vector<MachineInstr*>::iterator It = CallRetInstrList.begin();
+  for( ; It != CallRetInstrList.end(); ++It) {
+    MachineInstr *MInst = *It;
+    MachineOpCode OpCode = MInst->getOpCode();
+
+    if ((TM.getInstrInfo()).isReturn(OpCode))
+      MRI.suggestReg4RetValue(MInst, *this);
+    else if ((TM.getInstrInfo()).isCall(OpCode))
+      MRI.suggestRegs4CallArgs(MInst, *this);
+    else 
+      assert( 0 && "Non call/ret instr in CallRetInstrList" );
+  }
+}
+
+
+//--------------------------------------------------------------------------
+// The following method coalesces live ranges when possible. This method
+// must be called after the interference graph has been constructed.
+
+
+/* Algorithm:
+   for each BB in function
+     for each machine instruction (inst)
+       for each definition (def) in inst
+         for each operand (op) of inst that is a use
+           if the def and op are of the same register type
+	     if the def and op do not interfere //i.e., not simultaneously live
+	       if (degree(LR of def) + degree(LR of op)) <= # avail regs
+	         if both LRs do not have suggested colors
+		    merge2IGNodes(def, op) // i.e., merge 2 LRs 
+
+*/
+//---------------------------------------------------------------------------
+
+
+// Checks if live range LR interferes with any node assigned or suggested to
+// be assigned the specified color
+// 
+inline bool InterferesWithColor(const LiveRange& LR, unsigned color) {
+  IGNode* lrNode = LR.getUserIGNode();
+  for (unsigned n=0, NN = lrNode->getNumOfNeighbors(); n < NN; n++) {
+    LiveRange *neighLR = lrNode->getAdjIGNode(n)->getParentLR();
+    if (neighLR->hasColor() && neighLR->getColor() == color)
+      return true;
+    if (neighLR->hasSuggestedColor() && neighLR->getSuggestedColor() == color)
+      return true;
+  }
+  return false;
+}
+
+// Cannot coalesce if any of the following is true:
+// (1) Both LRs have suggested colors (should be "different suggested colors"?)
+// (2) Both LR1 and LR2 have colors and the colors are different
+//    (but if the colors are the same, it is definitely safe to coalesce)
+// (3) LR1 has color and LR2 interferes with any LR that has the same color
+// (4) LR2 has color and LR1 interferes with any LR that has the same color
+// 
+inline bool InterfsPreventCoalescing(const LiveRange& LROfDef,
+                                     const LiveRange& LROfUse) {
+  // (4) if they have different suggested colors, cannot coalesce
+  if (LROfDef.hasSuggestedColor() && LROfUse.hasSuggestedColor())
+    return true;
+
+  // if neither has a color, nothing more to do.
+  if (! LROfDef.hasColor() && ! LROfUse.hasColor())
+    return false;
+
+  // (2, 3) if L1 has color...
+  if (LROfDef.hasColor()) {
+    if (LROfUse.hasColor())
+      return (LROfUse.getColor() != LROfDef.getColor());
+    return InterferesWithColor(LROfUse, LROfDef.getColor());
+  }
+
+  // (4) else only LROfUse has a color: check if that could interfere
+  return InterferesWithColor(LROfDef, LROfUse.getColor());
+}
+
+
+void LiveRangeInfo::coalesceLRs()  
+{
+  if(DEBUG_RA >= RA_DEBUG_LiveRanges) 
+    std::cerr << "\nCoalescing LRs ...\n";
+
+  MachineFunction &MF = MachineFunction::get(Meth);
+  for (MachineFunction::iterator BBI = MF.begin(); BBI != MF.end(); ++BBI) {
+    MachineBasicBlock &MBB = *BBI;
+
+    // iterate over all the machine instructions in BB
+    for(MachineBasicBlock::iterator MII = MBB.begin(); MII != MBB.end(); ++MII){
+      const MachineInstr *MI = *MII;
+
+      if( DEBUG_RA >= RA_DEBUG_LiveRanges) {
+	std::cerr << " *Iterating over machine instr ";
+	MI->dump();
+	std::cerr << "\n";
+      }
+
+      // iterate over  MI operands to find defs
+      for(MachineInstr::const_val_op_iterator DefI = MI->begin(),
+            DefE = MI->end(); DefI != DefE; ++DefI) {
+	if (DefI.isDef()) { // this operand is modified
+	  LiveRange *LROfDef = getLiveRangeForValue( *DefI );
+	  RegClass *RCOfDef = LROfDef->getRegClass();
+
+	  MachineInstr::const_val_op_iterator UseI = MI->begin(),
+            UseE = MI->end();
+	  for( ; UseI != UseE; ++UseI) { // for all uses
+ 	    LiveRange *LROfUse = getLiveRangeForValue( *UseI );
+	    if (!LROfUse) {             // if LR of use is not found
+	      //don't warn about labels
+	      if (!isa<BasicBlock>(*UseI) && DEBUG_RA >= RA_DEBUG_LiveRanges)
+		std::cerr << " !! Warning: No LR for use " << RAV(*UseI)<< "\n";
+	      continue;                 // ignore and continue
+	    }
+
+	    if (LROfUse == LROfDef)     // nothing to merge if they are same
+	      continue;
+
+	    if (MRI.getRegTypeForLR(LROfDef) ==
+                MRI.getRegTypeForLR(LROfUse)) {
+	      // If the two RegTypes are the same
+	      if (!RCOfDef->getInterference(LROfDef, LROfUse) ) {
+
+		unsigned CombinedDegree =
+		  LROfDef->getUserIGNode()->getNumOfNeighbors() + 
+		  LROfUse->getUserIGNode()->getNumOfNeighbors();
+
+                if (CombinedDegree > RCOfDef->getNumOfAvailRegs()) {
+                  // get more precise estimate of combined degree
+                  CombinedDegree = LROfDef->getUserIGNode()->
+                    getCombinedDegree(LROfUse->getUserIGNode());
+                }
+
+		if (CombinedDegree <= RCOfDef->getNumOfAvailRegs()) {
+		  // if both LRs do not have different pre-assigned colors
+		  // and both LRs do not have suggested colors
+                  if (! InterfsPreventCoalescing(*LROfDef, *LROfUse)) {
+		    RCOfDef->mergeIGNodesOfLRs(LROfDef, LROfUse);
+		    unionAndUpdateLRs(LROfDef, LROfUse);
+		  }
+
+		} // if combined degree is less than # of regs
+	      } // if def and use do not interfere
+	    }// if reg classes are the same
+	  } // for all uses
+	} // if def
+      } // for all defs
+    } // for all machine instructions
+  } // for all BBs
+
+  if (DEBUG_RA >= RA_DEBUG_LiveRanges) 
+    std::cerr << "\nCoalescing Done!\n";
+}
+
+/*--------------------------- Debug code for printing ---------------*/
+
+
+void LiveRangeInfo::printLiveRanges() {
+  LiveRangeMapType::iterator HMI = LiveRangeMap.begin();   // hash map iterator
+  std::cerr << "\nPrinting Live Ranges from Hash Map:\n";
+  for( ; HMI != LiveRangeMap.end(); ++HMI) {
+    if (HMI->first && HMI->second) {
+      std::cerr << " Value* " << RAV(HMI->first) << "\t: "; 
+      if (IGNode* igNode = HMI->second->getUserIGNode())
+        std::cerr << "LR# " << igNode->getIndex();
+      else
+        std::cerr << "LR# " << "<no-IGNode>";
+      std::cerr << "\t:Values = "; printSet(*HMI->second); std::cerr << "\n";
+    }
+  }
+}
+
+} // End llvm namespace